Ovaries and Uterus

Question 1

Parts of the oviduct

Answer 1

1. Infundibulum - (funnel-shaped portion nearest the ovary)
2. Ampulla (expanded middle portion)
3. Isthmus (narrowed portion connecting the ampulla to the uterine horn)

Question 2

Site of fertilisiation

Answer 2

Junction of the ampulla and isthmus within the oviduct

Question 3

Treatment of oviductal blockage

Answer 3

1. Laparoscopic PGE2 gel application 2. Hysteroscopic PGE2 gel application at the tip of the horn

Question 4

Role of PGE2 in oviductal blockage

Answer 4

Relaxation of circular smooth muscle facilitating oviductal transport of oocyte/embryo May also contract longitudinal smooth muscle (shown in rabbits and pigs)

Question 5

What day does the fertilised embryo enter the uterus of the mare?

Answer 5

Between days 6-7 after ovulation

PGE2 gel application best performed day 4-5 post ovulation to facillitate passage of the embryo

Question 6

Advantages & disadvantages of laparoscopic vs other methods of ovariectomy

Answer 6

+ Superior visualisation

+ Tension free haemostasis

+ Direct observation of the pedicle during ligation and ability to act if haemostasis is deemed inadequate

+ Minimally invasive = lower morbidity and faster recovery

• Increased equipment cost
• Requirement for expertise

Question 7

List possible surgical approaches for ovariectomy

Answer 7

1) Laparoscopic (unilateral or bilateral approaches)
2) Colpotomy (traditional approach with ecraseur)
3) Ventral midline lap
4) Flank lap
5) Caudal or diagonal paramedian lap
6) Transvaginal natural orifice trans-luminal endoscopic surgery via colpotomy

Question 8

Which 2 methods are available for unilateral left PLF approach for bilateral ovariectomy

Answer 8

1) Left approach with dorsocranial retraction of the mesocolon (Colbath et al 2017 VS)
2) Left approach with mesocolon fenestration for access to the right ovary (Devick and Hendrickson 2019 VS)

Question 9

Indications for bilateral ovariectomy

Answer 9

1) Control of undesirable behaviour
2) Creation of jump mares
3) Prevention of pregnancy
4) Elimination of oestrus related abdo pain
5) Control of oestrus induced laminitis
6) Use as an ET recipient
7) Removal of bilateral neoplasms
8) Chronic pyo non-responsive to medical tx (without hysterectomy)- Jones EVE CR 2020

Question 10

Ligaments of the ovary

Answer 10

1) Suspensory ligament - lies in the cranial free border of the mesovarium, attaching to the sublumbar region
2) Mesovarium - peritoneal bilayer containing vasculature and lymphatics and providing support. Continuous with mesosalpinx and mesometrium. Suspended from lateral sublumbar and pelvic walls
3) Proper ligament of the ovary. Attaches the caudal pole of the ovary to the uterine horn

Question 11

Surgical approach described by Devick and Hendrickson (2019 VS) for unilateral left laparoscopic bilateral ovariectomy

Answer 11

1. Three portal left PLF technique - standard portal and a 5cm craniodorsal and caudoventral portal
2. Used 57cm 30° scope insufflated to 12mmHg
3. Blocked the left mesovarium
4. ID an avascular region in the mesocolon and made 5–6cm vertical incision half way between the root of the mesocolon and the attachment to the descending colon with laparoscopic scissors following splash block
   5) Right ovary visualised through the fenestration, mesovarium blocked
   6) Grasped right ovary, mesosalpinx and proper ligament were transected with laparoscopic scissors just caudal to the ovary and extending 1–2 cm dorsally
   7) Placed 2 ligatures w 4S modified Roeder knot with USP 1 polyglyconate (Maxon) placed in a knot pusher with extra-corporeal knot tying
   8) Pedicle transected with laparoscopic scissors and ovary dropped and maintained within the abdomen. Procedure repeated for the left ovary
   9) Mesocolon incision closed w laparoscopic staples spaced at 5mm intervals
   10) Cruciate skin sutures for portals

Question 12

Outcomes for left PLF bilateral ovariectomy reported by Devick and Hendrickson (2019 VS)

Answer 12

No intra-op complications

Mild incisional complications (emphysema) in 2/5 which was self-resolving

All 5 cases returned to intended use with owner satisfaction by 90d PO

Question 13

Possible complications of colpotomy

Answer 13

1) Fatal haemorrhage
2) Peritonitis
3) Adhesion formation
4) Eventration
5) Abscess formation
6) Delayed incisional healing
7) Tearing of cervical musculature
8) Intermittent straining
9) Colpotomy is not appropriate for mares with urine pooling or an infection of the vagina, cervix, or uterus

Risk of most of these complications is increased by 2 portal approaches, such as transvaginal natural orifice transluminal endoscopic surgery

Question 14

How many times can a ligasure likely be re-used and what sterilisation method was reported by Valenzano et al 2019 (VS)

Answer 14

5mm jaw handpieces, mean cycles to failure 7.7 (range 4-12). Usually failed by inability to activate the handset (11/12).

Only 1/12 failed by inability to hold adequate vascular seal > 300mmHg

Hydrogen peroxide gas sterilisation was used

Question 15

Maximum vessel diameter that a Ligasure can safely ligate and vessel seal bursting pressure

Answer 15

7mm vessel diameter

360mmHg bursting pressure

Question 16

Key features of ovarian anatomy in the mare

Answer 16

Approx 8x5cm

Palpable depression along the ventral free border = ovulation fossa

Suspended dorsally by mesovarium (contributes to borad lig and cr border is suspensory lig)

Cortex and medulla are inverted

Flat ovarian surface - large follicles/corpora lutea only protrude slightly (cf the cow)

Question 17

Briefly describe uterine blood supply

Answer 17

1. Uterine artery - a branch of the external iliac. This anastomoses with 2 and 3
2. Uterine branch of ovarian aa (a branch of aorta)
3. Uterine branch of vaginal aa (from internal pudendal)

Question 18

Main anatomical features of the uterus

Answer 18

T-shaped, horns and body roughly equal length

Bifurcation most dependent

Most positioned in the peritoneal cavity, caudal body and cervix retro-peritoneal / within pelvic cavity

Suspended by the mesometrium; continuous w mesosalpinx and mesovarium to form broad ligament

Question 19

What are the 3 categories/ tissue origins of ovarian neoplasm?

Which tumour type is the most common & what category does it come into?

Answer 19

1. Surface germinal epithelium origin
2. Sex cord-stromal tissue origin
3. Germ cell origin

Most common equine neoplasm is granulosa theca cell tumour (GCT) → sex cord stromal neoplasm

Question 20

Clinical singns of GCTs

Answer 20

Usually display 1 of 3 behavioural traits - Anoestrus (approx 32%), intermittent or continuous oestrus (nymphomania) (approx 22%), or stallion-like behaviour (approx 46%)

Less common CSs incl lameness, colic and wt loss as well as incr. muscle mass and enlarged clitoris

Most common ovarian neoplasm, accounts for 85% equine reproductive tumours

Question 21

Dx of GCT

Answer 21

1. US appearance - variable but commonly multicystic/honeycombed. Can be solid mass or singular large fluid filled cyst. Multiple US better than single to help differentiate (eg HAF). Affected ovary often has thick capsule/tunica albuginea surrounding a multicystic core. Contralateral ovary usually small v little/no follicular activity
2. Hormonal assays;
   a) testosterone elevated above that in normal cycling mares in 40-50% affected mares - 48% sensitivity
   b) inhibin - 80% sensitivity
   c) AMH - 98% sensitivity
   d) testosterone/inhibin combined - 94% sensitivity
   e) progesterone - invariably low dt absence of luteal tissue, P4>1ng/ml suggest no GCT
3. A jeuvenille form of GCT has been reported. Presents w haemoabdomen

Question 22

Differential diagnoses for GCT

Answer 22

1. Other ovarian neoplasms incl. teratoma, cystadenoma, adenocarcinoma, lymphosarcoma, melanoma, dysgerminoma, and arrhenoblastoma
2. Non-neoplastic conditions incl haematoma, abscessation, cysts

Question 23

Discuss indications and technique for ovariectomy by conventional colpotomy

Answer 23

Indications are removal of normal sized ovaries for breeding control, teasers etc

• Performed in dioestrus/anoestrus (less vascular) - use epidural, evacuate rectum & cath bladder
• 1-2cm colpotomy incision made w bistoury or guarded scalpel 4-5cm caudolateral to the cervix at either 2,4,8 or 10 o’clock position.
• Digitally enlarge the incision to accomodate a hand; locate the ovary and ensure not covered by any other tissue (eg intestinal mesentery).
• Lido soaked gauze held on the pedicle for 1 min
• The chain loop of the écraseur is placed around an ovary, excluding ALL other tissues & gradually tightened over 3-4mins until the overy becomes loose in your hand
• Repeat for the other side via same colpotomy
• Vaginal incision heals by 2° intention - manage X-tied 2-3d to help prevent eventration
• Caslick may help reduce contamination of the caudal repro tract PO
• 5d NSAID and AB

Question 24

Which modifications of the conventional colpotomy technique may reduce complications

Answer 24

• Hand assisted laparoscopic techniques; colpotomy made under lap visualisation from the abdominal side at the 10 o’clock position then enlarged by a hand in the vagina
• Transection of the pedicle can be achieved with Ligasure laparoscopically or via a chain ecraseur through the colpotomy
• Ovary is removaed vaginally & procedure repeated for contralateral side
• 19/21 were achievable with left flank approach - 2 needed additional right flank approach for visualisation
• Other techniques desc. closure of the colpotomy under lap guidance or 2° intention healing

Question 25

Which laparotomy approaches are available/appropriate for ovariectomy?

What are the main advantages and disadvantages of each?

Answer 25

1. Flank laparotomy - Best suited if <15cm. Limited by narrow PLF in horses vs cows. Main complication is (allbeit usually mild) incisional complications. Can use grid (<10cm), modified grid or sharp dissection techniques. Not well suited for bilateral procedures; either need to op from both sides or ligate contralat OV blind w ecraseur. Can be done standing. Incisions can be painful PO
2. Ventral midline - technique of choice for v large ovaries with stretched pedicles. Easy to extend. Can perform bilateral procedure. Good cosmesis providing adequate closure and lack of incisional complications. Hard to achieve ligation v minimal tension on pedicle; effect on BP…myopathy etc
3. Ventral paramedian - more haemorrhage and harder closure vs midline (most suited for cypts or access to the bladder in males - suprapubic paramedian). Otherwise similar to ventral midline. Contralateral ovary transected blind through same incision or have 2 incisions.
4. Diagonal paramedian - useful for normal or enlarged ovaries (20-25cm). Less tension applied to the pedicle during ligation vs ventral midline as incision placed v close to intra-abdominal position of ovary. Improved visualisation for same reason. Thinner body wall means greater exposure/visualisation of pedicle. Need 2 incisions for bilateral procedure and has to be GA obv. Layers incised are skin, SQ, ext rectus sheath, rectus abdo, int rectus sheath & peritoneum. Usually good cosmesis, PO confinement 2-4wk; full exercise 60-90d

Question 26

Mares undergoing ovariectomy by colpotomy should be in what stage of the estrous cycle?

a. immediately after ovulation
b. diestrus or anestrus
c. actively cycling
d. pregnant
e. seasonal transition

Answer 26

b. diestrus or anestrus

Vascualture least engorged at these times

Question 27

The initial vaginal incision for the colpotomy approach to ovariectomy should be in which position?

a. directly dorsal
b. on the medial wall
c. on the lateral wall
d. cranioventral or craniodorsal
e. directly ventral

Answer 27

d. cranioventral or craniodorsal

Craniodorsal at the 2- or 10- o’clock or a cranioventral at the 4- or 8-o’clock position.

Potential complications of a misplaced incision include entering the rectum (incision too dorsal), injuring the urethra or bladder (incision too ventral), and incising the caudal uterine branch of the urogenital artery (incision too medial or lateral (at the 3- or 9- o’clock position)).

The incision should be started 3-5cm caudal to the os cervix to avoid disruption of cervical musculature

Schumacher says incision should be at 13:30 for right handed and 10:30 for left handed surgeons to avoid the vaginal artery by going dorsal to it. Aa can usually be palpated in a distended vagina

Question 28

Oversewing the mesovarium following transection is recommended for which of the following reasons?

a. decrease adhesion formation
b. prevent eventration
c. provide analgesia
d. ensure adequate hemostasis
e. complete sterilisation

Answer 28

a. decrease adhesion formation

Question 29

Which of the following is considered the main advantage to the ventral midline celiotomy approach to ovariectomy?

a. little interference from abdominal viscera
b. ease of performing a bilateral procedure
c. optimal visualisation of ovaries on short pedicles
d. most tension-free ligation
e. the ability to extend the incision as needed

Answer 29

e. the ability to extend the incision as needed

Bilateral procedure can also be performed with relative ease

Ligation is only tension free when dealing with v large ovaries with stretched mesovarium; technique of choice for very large ovaries

Question 30

Which of the following is generally not used for hemostasis when performing laparoscopic ovariectomy?

a. suture ligatures
b. staples
c. chain ecraseur
d. laser energy
e. electrosurgical instrumentation

Answer 30

d. laser energy

Depending on approach; TA-90 staplers, ligasure, suturing and chain ecreaseur all described

Question 31

What is the main theory for why intraoperative hypotension is associated with traditional ovariectomy procedures performed under general anesthesia?

a. Tension on the mesovarium decreases arterial blood pressure.
b. Blood loss from the surgical incision causes hypovolemia.
c. Hypoventilation causes decreased arterial oxygen content.
d. Anaesthetic agents cause decreased systemic BP
e. Abdominal viscera interfere with venous return to the heart.

Answer 31

a. Tension on the mesovarium decreases arterial blood pressure.

Tension placed on the mesovarium during the process of exteriorising an ovary is speculated to cause a decrease in arterial blood pressure and potentially lead to inadequate peripheral circulation

Question 32

Which incision location has been associated with a higher incidence of complications?

a. ventral midline
b. paramedian
c. laparoscopic
d. flank
e. diagonal paramedian

Answer 32

d. flank

Flank incisions generally assoc. with higher rates of complications. Mainly swelling, seroma, pain. Catastrophic complications (hernia formation) are uncommon with flank incisions

Question 33

What percentage of mares stop showing oestrous behavior following bilateral ovariectomy?

a. 100%
b. 60%
c. 75%
d. 50%
e. 30%

Answer 33

b 60%

Ovariectomised mares may continue to display signs of oestrus after ovariectomy; approx 60% of ovariectomised mares will cease oestrous behavior PO

If previous hormonal therapy has been successful in altering the mare’s behavior and/or performance favorably, then bilateral ovariectomy is likely to be successful at meeting the client’s expectations.

Prospective “jump” mares to be used for stallion collection should stand well during estrus as an intact mare; otherwise, the individual is not likely to be a good candidate for ovariectomy for this purpose.

Question 34

Which of the following are advantages to laparoscopic ovariectomy approaches compared with the traditional laparotomy approaches?

a. smaller incisions for access to the abdomen
b. superior visualisation of the ovary and mesovarium
c. tension-free ligation of the mesovarium
d. shorter, less complicated PO recovery
e. all of the above

Answer 34

e. all of the above

Laparoscopy excellent for ovariectomy. Main downside is requirement for equipment and expertise

Question 35

Which of the following is not a reported complication following equine ovariectomy?

a. septic peritonitis
b. eventration
c. neurologic deficits
d. hemorrhage
e. hindlimb pain

Answer 35

c. neurologic deficits

Not been reported post ovariectomy

Question 36

Indications for bilateral ovariectomy

Answer 36

1. Prevention of pregnancy (100% effective)
2. Prevention of oestrus behaviour - 80% will improve. Approx 30-40% may continue to show some signs of oestrus behaviour.
3. Elimination of colic signs assoc. with ovulation
4. Management of mares with chronic pyometra &/or endometritis that are resistant to routine tx
5. Use as a ‘jump’ / teaser mare

Question 37

What is the name of this instrument?

Answer 37

Tenaculum forceps; provide a secure grasp of the ovary with complete jaw closure, reducing instrument interference during morcellation

Question 38

Key points in standing laparoscopy for bilateral ovariectomy

(from laparoscopy book)

Answer 38

1. Perform in dioestrus/anoestrus. Ideally rectal pre-op - evacuate rectum, check PLF region etc
2. Sx generally easier standing dt to dorsally suspended ovary.
3. Decrease GI bulk pre-op; aim for PLF concavity - can vary from 12-72 hrs
4. Portal locations for 2 portal techniques; left - ventral TC in ICS 17 for scope, instrument 5cm ventral to the dorsal crus of IAO mm in the centre of PLF. Right scope caudal to last rib just dorsal to IAO mm and instrument 5cm caudal and ventral to this (additional portals can be made if required intra-op)
5. All but the first portal on the left are made under lap visualisation
6. Mesovarium blocked. Ligasure used to ligate/transect the pedicle from cranial or caudal (cranial easier but can dissect too far caudal down mesometrium)
7. Leave 5mm mesovaium attachment but make sure the proper ligament of ovary is transected or will risk morcellating the uterine horn
8. Introduce morcellator (need to enlarge portal to 15mm) and forceps grasp ovary through the portal of the morcellator
9. Morcellation must be visualised; ovary peeled and removed in sections (typically 3-7)
10. Repeat for the other side, decompress abdo and close; skin only usually sufficient

Question 39

Potential complications of laparoscopic ovariectomy

Answer 39

1. Risk of damage to internal organs (e.g., spleen, kidney, cecum, mesovarium, mesocolon, and descending colon) or failure to enter the peritoneal cavity during portal creation; best avoided using canulas that can be placed with the scope inside them. Also helpful to establish first scope portal in the LEFT 17th ICS where the peritoneum is tightly adherent to the ribs and less likely to create retroperitoneal space that degrades the field of view. NB this is not the case on the right where the peritoneum is NOT well adhered to the ribs
2. Other complications are few. May see transient peritonitis w CO2 insufflation. Depending on method of haemostasis, haemorrage.. all quite uncommon

Question 40

Key points for standing laparoscopic removal of abnormal/oversized ovaries

(Limitations, contraindications etc)

Answer 40

1. Main limitation in removing ovaries >15cm is phyically getting them out of the abdomen; tension free haemostasis remains achievable with electrosurgical instruments. Large flank incisions are assoc w incr. complications incl haem, prolonged sx time, seroma formation, wound dehiscence & infection. Size of the ovary itself does NOT limit ability for standing lap approaches
2. Alternativec incl morcellators (expensive), retrieval bags, intraabdominal suction, & dissection
3. No true contraindications for laparoscopic ovariectomy but need to be prepared to convert to GA ventral midline approach if there are significant adhesions to abdominal viscera

Question 41

Equipment required for standing laparoscopic ovariectomy (for unilateral oversize ovary removal)

Answer 41

1. 10 mm, 32-cm rigid 0° or 30° laparoscope (angled may facillitate visualisation) (long laparoscope is less practical but needed if trying to perform bilateral procedures from same side - 57cm)
2. 3 × 10-mm-diameter, 20-cm-long trocar-cannula unit (1 for the scope, 2 for instruments)
3. Reducers from 10 to 5 mm (so air doesn’t escape around 5mm instruments)
4. Laparoscopic injection needle (for blocking ovarian pedicle)
5. Laparoscopic scissors (5 or 10 mm)
6. Largest size claw grasping forceps
7. Retrieval bag; Strong and large sterile plastic bag (e.g., sterile laparoscopic instrument bag or sterile plastic cover for X-ray cassette), OR commercial retrieval bag (largest diameter ±15cm)
8. 30-40cm long, 5-10-mm diameter cannula with semisharp trocar and suction for fluid aspiration from ovary
9. LigaSure or other electrosurgical vessel- sealing instruments

Question 42

Portal sites sx procedure for standing laparoscopic ovariectomy (unilateral diseased ovary)

From laparoscopy book

Answer 42

1. Scope portal is ICS 17 at or upto 5cm ventral to the ventral aspect of the tuber coxa (care re going too dorsal as will penetrate pleural cavity (see diagram) & 2 instrument portals in PLF
2. Alternatively, all 3 portals can be in the PLF
3. First portal placed blind without insufflation, made at the dorsal margin of the internal abdominal oblique muscle (mid tuber coxae level) midway between the last rib and the tuber coxae. Others placed w insufflation and lap visualisation (avoids injury to the spleen for eg)
4. Scope then changed to ICS 17 portal and 2nd instrument portal made +/-10cm ventral to 1st
5. Pedicle identified and blocked w 15-20ml 2% lido
6. Grasping forceps introduced through ventral instrument portal; some are heavy and hard to manipulate but should be able to lift to see proper ligament and uterine horn
7. 10mm LigaSure handpiece through dorsal portal; place jaws round cranial mesovarium approx 1cm dorsal to ovary dissected free with care to avoid uterus. Dissection can also be started in the caudal to cranial direction starting with dividing the proper ligament, salpinx, and mesosalpinx (technically harder but avoids dissexting down mesometrium)
8. Suture ligation for alternative haemostasis - 5- to 8-metric vicryl suture is placed around the pedicle and an extracorporeal 4S modified Roeder knot is tied and advanced using a knot pusher - can split mesovarium and place cranial and caudal sutures if large (better haemostasis and less slippage)
9. Ovary removal; enlarge instrument portal if <10cm. For larger ovaries, connect the 2 instrument portals and attmept size reduction of the ovary by aspiration of fluid (need pre-op UD and blunt cannula w suction), retrieval bags if solid ovary (introduced pre-pedicle dissection and via 15mm cannula or hand assisted technique) or morcellator
10. Close skin only if small incisions. Larger incisions closed in 3 layers; skin, SQ and muscle (either EAO alone or all together)

Question 43

Abdominal insufflation pressures for laparoscopic procedures

Answer 43

10-15mmHg

Some use cutoff of 12mmHg - safe bet

Question 44

Methods for reducing ovarian size for laparoscopic removal

Answer 44

1. Fluid aspiration - if ++ fluid filled on pre-op US. Blunt suction trachar can be push through the capsule and attahed to sunction, or small incision with scissors in capsule to facillitate its entry
2. For large solid mass ovaries that cannot be drained or ovaries that remain too big after fluid removal, intra-abdominal dissection within a strong retrieval bag is indicated. Commerical bags available upto 15cm, if larger need to improvise w sterile plastic bag.
   For commercial bags; introduce via 15mm cannula & opened by pulling the colored tabs using 5-mm grasping forceps, placed around ovary, drawstring partially closed then pedicle ligated/transected. Ovary can then be dissected within the bag for remova. For larger ovaries strong sterile plastic bag can be introduced intra- abdominally and the ovary manipulated into it, either by a hand-assisted intra-abdominal technique or by the use of grasping forceps (all need enlargement of a portal & may need 3rd instrument portal). Can be time consuming. Polypropelene bag of Hans Wildehans may be easier (pictured). Bring bag to incision and dissect portions of the ovary - care not to cut the bag
3. Motorised morcellator - stainless steel cylinder with a cone-shaped knife at its intra-abdominal end. A grasping forceps is inserted through this cylinder with the knife, and the ovary is grasped and pushed against the rotating knife. Cylindrical tissue blocks from 8-10mm thick & up to 30cm long can be cut from the ovary and removed from the abdomen using the grasping forceps. This is then repeated numerous times until the entire ovary is removed. The morcellator can also be used on a bagged ovary to prevent intra-abdominal contamination

Question 45

Expected outcome following laparoscopic GCT removal

Answer 45

The extreme behavioral changes like aggressiveness and stallion-like behavior will disappear quickly after surgery. Time to resumption of normal cyclical activity will range from a couple of weeks to 6 months depending on the duration of inhibition of the contralateral ovary.

Question 46

Potential complications during/following laparoscopic removal of large GCTs

Answer 46

1. Haemorrhage from the enlarged flank incisions (usually caudal circumflex iliac aa) - avoid w grid technique. Ligate if encountered
2. Adhesions between GCT and viscera or body wall may be encountered; most can be laparoscopically dissected using a 5 or 10mm LigaSure or monopolar/bipolar laparoscopic dissection probe; if not possible can ligate pedicle and convert to ventral midline lap
3. Bleeding from mesovarium uncommon - reapply LigaSure/ligature
4. Wound healing complications - much fewer with smaller incisions. Larger incisions may expedite surgical time but more prone to complicaitons & poorer cosmetic outcome
5. Abdominal contamination - prevent with bagging where possilbe

Question 47

Surgical technique for dorsally recumbent laparoscopic ovariectomy

Answer 47

1. Abdomen insufflated to 10-15mmHg via teat cannula through stab incision at the umbilicus
2. Teat cannula replaced w 10mm trochar/cannula unit
3. Tilt to Trendellenberg and create 2 instrument portals under visual guidance approx 20cm abaxial and 20cm caudal to the umbilicus (care re caudal superficial epigastric vessels either side of rectus abdominis)
4. Grasping forceps used to ID and grasp ovary & the proper ligament of the ovary is transected with the coagulating/dividing device
5. Mesovarium now ligated/transected (electrosurgery, ligating loops, Roeder knots, polyamide tie wraps, harmonic scalpel, endoscopic stapling devices all reported)
6. Once detached, either ‘park’ the ovary on the pelvis while you do the other side, or create another portal to grasp it
7. Repeat for other side if bilateral
8. Place both in specimen bag or remove w grasping forceps by enlarging the umbilical portal
9. Once the ovaries are removed, the linea is apposed with #1 vicryl in a cruciate pattern. The skin is closed with 3-0 vicryl in a simple continuous pattern. 5mm instrument portals have skin only closed. 10mm portals have the external fascia of the rectus closed with #1 vicryl in an inverted cruciate pattern and the skin closed with 3-0 vicryl.

Question 48

Possible complications of dorsally recumbent laparoscopic ovariectomy

Answer 48

1. Haemorrhage - have several methods available incase 1 fails
2. Inadequate visualisation of the ovaries - poor starvation, bladder distension or v short mesovarium (better done standing)
3. Damage to adjacent viscera
4. PO colic - responds to analgesia in the majority

Question 49

Indications for removal of uterine cysts

List possible methods that this can be done

Answer 49

Can remove if suspicious of causing/contributing to infertility

High number or large size (may interfere with embryonic migration/MRP) or positioned at the base of horns (site of fixation). May also be a hx of early embryonic loss

Methods for removal incl:

mechanical curettage, rupturing the cyst manually or with endometrial biopsy forceps, uterine lavage with a hypertonic saline or magnesium sulphate solution, electrocoagulation of the cyst, and laser ablation

Question 50

Describe the procedure for laser ablation of uterine cysts

What is the expected outcome following this procedure?

Answer 50

• Preferably in dioestrus/anoestrus so uterine insufflation is maintained
• Hysteroscopy (sterile scope), distend the uterus with air/CO2; care not to over-inflate (damage endometrium)
• Diode laser through biopsy channel at 20W to puncture and drain each cyst, then continue lasering until the remaining cystic tissue has been ablated and the base is charred. Smoke and fluid often need evacuated during the procedure
• Can distend with sterile fluid and do ‘underwater’ to avoid smoke production - helpful if numerous cysts but requires more laser energy per cyst as fluid absorbs some energy
• Uterine lavage and AB infusion daily for 2-3d PO. Systemic NSAIDs 5d
• Scan per rectum approx 30d PO before breeding

A report of Nd:YAG laser ablation in 55 mares demonstrated improved fertility

Another study, 46 mares. 56% of mares bred the same year delivered a live foal and 73% of mares bred the subsequent year

Mares <17 years were more likely (96%) to produce a live foal than those older - (58%)

Number and location of cysts didn’t have an effect on post-op fertility

Question 51

What feature about the position of the uterus in older, multiparaous mares may rx in infertility dt poor uterine clearance and persistent mataing induced endometritis?

What can be done to treat this?

Answer 51

The nongravid uterus is normally oriented horizontally within the abdominal cavity, but the weight of numerous foals may result in stretching of the mesometrium, causing the uterine body and horns to become oriented ventrally → stregth of contractions ∴ insufficient to clear intra-uterine debris

A ventrally positioned uterus can be returned to a normal, horizontal orientation by imbricating the two mesometria that suspend the uterine body and each horn

Question 52

Describe the laparoscopic technique for mesometrial imbrication of the uterus

Answer 52

1. Std portals; sx from left 1st so caecum drops from right flank when abdo pressure equilibrates. Sites are (1) ICS 17 at ventral TC level (cranial portal), (2) midway between the ventral TC & last rib at dorsal crus of IAO mm (middle portal), & (3) 6cm ventral & 2cm caudal to 2 (caudal portal)
2. Need larger trochar/canula units - 14mm and 25mm for middle portal (can use 60ml syringe if ++ insufflation not required)
3. Scope cranially, needle holder & suture (PG910 1.5m on large round bodied needle) (or EndoStitch w 3.5-metric (0) braided, polyglycolide colactide attached to the center of a 9mm long, 0.9mm wide needle sharp on both ends) via larger middle & instrument caudal portal
4. Imbrication begins caudally at the body; through seromuscular layers of the dorsolateral aspect of the body of the uterus, adjacent to the reflection of the mesometrium onto the uterus, and then through the mesometrium about 3cm dorsal to its uterine attachment
5. First suture anchored by passing through pre-made loop, then continue cranially to horn tip - sutures are placed 1.5cm apart, & about 10–14 suture bites are required
6. Suture is not placed near the tip of the uterine horn to avoid damaging the uterine opening of the oviduct. The cranial end of the continuous suture line can be tied extra or intracorporeally depending on the skill of the surgeon
7. Repeat for right side
8. Close EAO, skin, SQ on larger portals and skin/SQ only on smaller

Question 53

What procedure is being performed?

Which horses are likey to benefit?

What is the expected outcome WRT fertility?

Answer 53

Laparoscopic imbrication of the mesometrium

Used to treat older multiparous mares that have ventrally positioned uteri rx in poor uterine clearance, endometritis & infertility

No large studies to verify effect on fertility

In one report (Brink 2010), 3 of 4 chronically infertile mares became pregnant and delivered a foal after uteropexy (barren upto 5 yrs)

The procedure also rx in immediate improvement in vulvar conformation, since enlarged/pendulous uterine horns drag the rectum and vagina cranially, which rx in a sunken anus and a horizontal tilt to the vulva.

Authors also suggest the technique would be valuable for correction of urine pooling, which is often associated with poor perineal and uterine conformation. Some mares with chronic endometritis have experienced resolution of bacterial infection and endometritis without other treatments.

Question 54

Indications for complete or partial ovariohysterectomy (OVH)

Answer 54

Complete: chronic pyometra, neoplasia (NB leiomyoma mainly), uterine torsions with ischaemia, mucometra w cervical adhesions

Partial: solitary masses, even if large (NB usually leiomyoma)

Question 55

Possible approaches for complete OVH.

Briefly describe each

Answer 55

1) Caudal ventral midline laparotomy - difficult as maximal tension rx in minimal exteriorisation dt dorsal location of repro tract. Ovariectomy first (LigaSure preferably) & cont dissection caudally. Transect ut body as far caudal as possible. Pre-place sutures caudally. Transect in 5cm sections and close each section w USP 2 cont Lembert. Then oversew entire stump in same suture/pattern.
2) Laparoscopic assisted - mesovarium and mesometrium transected as far caudally as possible laparoscopically (standing or GA). Then GA caudal ventral midline incision for transection/closure of uterus as above
3) Laparosopcic trasection of the mesovarium and mesometrium, followed by inversion of the uterus through the cervix and into the vagina, for resection of the uterus

Question 56

Describe the procedure for dorsally recumbent laparoscopic assisted OVH

(from laparoscopy book)

Answer 56

1. GA dorsal. Scope at umbilicus & 2 instrument portals on each side of the abdo (see dia) in the axial half of the rectus muscle to avoid the deep epigastric vessels. The cranial portals are 1/2 between umbilicus & mammary gland. Caudal portals are several cm caudolateral to this
2. 30° Trendel after scope portal established.
3. Initallly as for ovariectomy - Semm claw forceps in the right caudal instrument portal to grasp RO & a Chambers mare catheter in the left caudal instrument portal to elevate UT horn
4. LigaSure in right cranial portal for right mesovarium ligation/transection
5. Repeat for left side. Ovaries placed in specimen bags or morcellated/removed
6. Tip of the horn is grasped and elevated to expose the broad ligament, which is divided w Ligasure ideally; vascular clips or staples could be needed when transecting the uterine artery (may exceed 7mm). Dissection is continued until both horns are freed just caudal to the body
7. Scope placed in a lateral portal and Semm forceps in umb portal to grasp tips of horns
8. Midline incision extended from umb to mammary and horns exteriorised
9. Traction applied for max exposure & 2 Doyen clamps applied across caudal body
10. Transect between clamps and close stump in 2 layers: simple continuous appositional then continuous inverting pattern w USP1 monofilament absorbable suture
11. Close midline in 2 layers (LA and intra-derm) and smaller portals in 1, larger in 2 layers

Question 57

List possible treatment options for chronic pyometra

Answer 57

1. Initially uterine lavage, ABs (C+S) and cervical adhesiolysis
2. If unsuccessful, cervical wedge resection can be performed; standing with caudal epidural - stay sutures in the cervix to retract caudally - a full thickness wedge defect is (3-4cm wide with the apex pointing cranially from the external os extending to the internal os) is removed from the dorsolateral aspect of the cervix using long Mayo scissors. Not sutured - establishes permanent drainage into the uterus
3. OVH required if wedge resection fails

Question 58

What procedure is being performed?

What are the possible complications of this procedure (by this or other methods)?

Answer 58

Ovariohysterectomy

Most commonly see abdominal pain and incisional drainage or infection

Haemorrhage, septic peritonitis, uterine stump infection (avoid transfixation of the uterine stump), necrosis, and abscessation are less common but potentially life threatening complications

Cervical scarring or adhesions assoc. with incr complicaiton rate. Perform cervical wedge resection or leave indewlling Foley PO to try and improve drainage/reduce complications

Question 59

Indications and approaches for partial OVH

Expeted outcomes

Answer 59

• Solitary masses - even if large
• Approaches incl. caudal ventral midline/paramedian laparotomy & standing flank laparoscopy.
• Live foals have been produced from mares with some uterine horn removed
• Although impossible to quantify accurately, it appears that most mares can maintain a pregnancy with up to 50% of a uterine horn removed, but fertility decreases proportionally to the amount of horn removed beyond that

Question 60

When during gestation is uterine torsion most likely?

What is the estimated incidence and what might the aitiology be?

Answer 60

Usually third trimester - months 7-11

Months 9-11 most commonly. May occur at term

Present primarily with colic or dystocia (if term)

Estimated incidence <5-10% of severe dystocias

May occur dt foetal movement or rolling of the mare. Aitiology not well understood

Question 61

Diagnosis of uterine torsion

Answer 61

Rectal exam is the cornerstone - taught broad ligament is palpable, coursing dorsal to the caudal aspect of the uterus in the direction of the torsion. Usually can’t palpate the contralateral broad lig and ovary as pulled ventrally. Described as clockwise and anticlockwise in the standing position from behind the mare; ie clockwise = left BL coursing dorsally across the right, difficult to palpate the right BL and ovary. Can be difficult to determine direction esp if GI distension. Foetus displaced cranially by the torsion. Can be 180-540° torsion

Vaginal exam usually not diagnostic in the mare (vs cow where torsion commonly caudal to the cervix) although can be useful to assess for cervical dilation and discharge (NB scrupulous asepsis needs to be adhered to and use spec rather than hand)

US to assess for foetal viability/HR etc

Roughly equal incidence of clockwise/anti-clockwise torsions. Some say 60% clockwise some say 60% anticlockwise

Question 62

Non-surgical management options for corection of uterine torsion

Answer 62

1) Manual rotation through the cervix: only available in those mares at term (not many) w cervical dilation to accomodate a hard. Foetal membranes manually ruptured to ↓weight & foetus grasped and rocked in increasing arc until de-torsed. Upto 80% of torsions ≤270° can be corrected. Mare needs to remain standing. Epidural beneficial. Needs to enter 2nd stage labour immediately after (can give oxy if not)
2) Rolling: GA & roll in same direction of torsion ie w clockwise torsion → start in right and with a plank against the abdo, roll 360° into sorsal, left lat, sternal then back to right lat. Rectal in sternal after each attempt. Several attempts may be required but don’t persist for >1hr. Do not use close to term - ↑ risk of uterin rupture & other complications incl, premature placental separation, foetal death & abortion. Best suited for light-breed mares at 7-10 mo gestation where there are financial limits

Question 63

Surgical management options for uterine torsion

Answer 63

1) Standing flank laparotomy: Incision is on the side of the torsion (ie R for CW & vice versa), but have both sides prepared. Modified grid approach; place a hand under the gravid horn. Uterus is gradually rocked back and forth eventually allowing the uterus to flip back into its normal position. Alternatively, the foetal hocks may be gently grasped. To decrease the chance of uterine perforation, the uterus should be lifted and pushed, rather than pulled, into position. In the later stages of pregnancy, correction of torsion by a single flank incision may be difficult due to the size and weight of the foetus. Not well suited if v painful. The status of the foetus and of the uterus should be evaluated. Closure is routine.

2) Ventral midline laparotomy: most appropriate if uterine rupture, tearing, or devitalisation is suspected; if the foal is known to be dead and the mare is preterm; and if attempts at standing correction are unsuccessful. Alse required if can’t rule out concurrent GI abnormalities. Minimise wound length (15-20cm) so less strain at parturition. Catastrophic incisional dehiscence a genuine risk if in labour soon after sx. Help prevent by anaesthetising at onset of stage 2 to perfom controlled vaginal delivery. Hysterotomy can be performed at the same time if significant damage. Better access this approach & allows visualisation of other organs and uterine viability. Combine w caesarean if at term. May need to remove foetus before correction.

Question 64

Mare and foal survival following uterine torsion reported by Spoormakers 2016 (EVJ)

Answer 64

• After correction of UT, overall 90.5% mares and 82.3% foals survived to discharge
• For foals, survival was 88.7% after standing flank lap (SFL) vs 35% after other methods
• When UT occurred at <320 days, 90.6% of foals survived, compared with 56.1% at ≥320 days
• For mares, higher survival after SFL (97.1%) vs other methods (50%) at <320d gestation (& <360°rotation). When UT occurred at ≥320 days, mare survival did not differ between techniques (76 vs 68.8%)
• Of 123 mares that were bred again, 93.5% became pregnant; fertility did not differ between mares treated by SFL (93.9%) and other techniques (87.5%)
• Concluded that standing flank laparotomy is the surgical technique of choice for resolving uncomplicated equine UT occuring <320d gestation (i.e. with no coexisting gastrointestinal lesions)

Question 65

Mare and foal survival following uterine torsion reported by Chaney 2010

Answer 65

Overall mare survival was 84%; survival rate 97% if gestation < 320 days & 65% if gestation ≥320 d

Foal survival was 54%, survival rate 72% in foals <320d gestation and 32% in foals ≥320 d

Concluded that px for mare & foal improved if torsion occurred before 320 d gestation.

Increased foetal size/weight of the reproductive tract after 320 d may make correction more difficult, rx in ↓ survival dt compromised blood flow and tissue oxygenation

No significant difference in mare survival between methods of correction; however, when the torsion occurred before 320d gestation, standing flank laparotomy improved foal survival more than ventral midline laparotomy

Question 66

Clinical features of uterine prolapse

Answer 66

= Protrusion of uterus into and beyond the vaginal vault. Presents w highly vascular, red corrugated mass protruding from the vulva

Rare. Usually follows dystocia, RFM, or abortion (check uterus after dystocia - common for ovarian pole to be invaginated - can lead to complete prolapse if not corrected) within 48hrs of parturition

Relaxation of supporting tissue and elongation of broad lig facillitate occurrence

Manual removal of RFM or excessive oxytocin use have also been implicated

Life threatening emergency

Trauma to vessels can cause fatal haemorrhage

Question 67

Treatment of uterine prolapse

Answer 67

Best to manage on farm if poss

Support: Keep uterus positioned as high as pelvic brim to ↓ strain on vessels & supporting structures. Will be instantly more comfortable once supported

Cleanse: Aim to remove as much gross contam as poss w/ as little delay as poss. Clean with saline, warm water or dilute iodine

Evaluate: Remove placental attachments & evaluate thoroughly for tears; if present suture w 2 layer inverting pattern

Replace: Face mare downhill or into depression (can GA w HL elevation or Trendellenberg if unsuccessful standing). Heavy sedation +/- epidural (care latter if may need to GA). Manipuate w flat of the hand & even pressure, avoid fingertips (friable/rupture). Find everted horn tip, advance it through cervix and the rest will follow

Once reduced: Verify posn of both gravid and non-gravid horns to ensure no invagination, if not completely reduced, ↑ chance of colic, straining and recurrence. A rectal sleeve filled with water can be used to ensure complete eversion of the uterine horns (the tips of which are beyond the reach of the arm), or large volumes of warm, sterile saline may be infused and siphoned off. Tx with systemic and IU ABx. Pain relief. Suture vulva w umbilical tape or heavy suture material. Remove sutures and commence uterine lavage the next day. Oxytocin has been recommended post reduction, but may be best avoided for 1-2 days given discomfort and straining. Monitor closely for 72hrs - shock/sepsis etc

Question 68

Prognosis following uterine prolapse

Answer 68

Good if no uterine tears or artery damage (hypovolaemia, endotoxaemia)

Reproductive px is good; no tendency for repeat prolapse at subsequent pregnancies

Question 69

Clinical features of uterine tear/ruptures

Answer 69

CSs incl lethargy, depression, reduce appetite & fecal output, reduced milk production, pyrexia, tachycardia, hyperemic mucous membranes and abdominal guarding, may be mild colic

Usually present 1-3d post-partum (initially fine)

Commonly follow normal foalings; dt rapid thrusts of the foetal HLs ∴ more occur at the tip of the gravid horn (75%). Tears in the body/vagina are more likely dt penetration w foot/muzzle during dystocia (25%). Rare post uterine torsion

Occasionally, intestines or omentum may be identified within the uterine lumen, or even through the vulval opening

If large vessels damaged, may present w shock

Pre-term ruptures have been rarely reported - even a case report of a foetus discovered intra-abdominally at a later date following healing of the rupture and involution

Question 70

Dx of uterine rupture

Answer 70

Hx/CSs

Usually have ↑ free peritoneal fluid w elevated WCC and TP +/- bacteria (+ multinucleate trophoblasts)

May be able to palpate the tear at the tip of the horn by ‘walking’ fingertips down the horn

Question 71

Tx options for uterine tears

Answer 71

1) Conservative: oxytocin to facilitate expulsion of foetal membranes and uterine involution, IVFT, ABx, NSAIDs & anti-endotoxin therapy. +/- aminocaproic acid, laminitis prophylaxis, additional analgesia

2) Surgical:
a) ventral midline laparotomy, uterine closure (usually 2; continuous w inverting oversew w USP 2 multifilament suture) +/- abdominal lavage.
b) Tears in the caudal body have been reportedly repaired standing per vaginum w single layer simple USP2 sutures
c) Standing laparoscopic repair has also been reported in 3 mares (Diekstall 2020 EVE)
d) TOB does standing flank lap & sutures extracorporeally

Question 72

Expected prognosis following medical and surgical treatment of uterine tears

(Javsicas 2015 VS compares the 2 tx)

Answer 72

• No significant difference in STS between mares treated medically and surgically in 1 report (Javsicas et al 2015 VS) . Tx cost, duration of hosp, & days with a temp >101.51F or a HR >60/min were not sig diff between med and sx tx groups
• Overall 76% survival; 73% medical 76% surgical. No sig diff in survival rate for tear location (body versus horn; although Claunch 2015 suggests better px for horn (84%) vs body (58%)), detection of tear per vaginum, use of abdominal lavage, positive bacterial culture of p tap, presence of a polymicrobial infection, or use of oxytocin
• -ve px factors were presence of NG reflux, ↑ HR & anion gap, lower total CO2 & leukocyte counts
• 12/13 mares bred the same year conceived and carried the foal to term
• Most other texts suggest better px for sx tx and best (>90%) when performed within 24hr. Probably advisable to take surgical option if there is one, esp as the cost of medical management is likely to be high

Question 73

Outcomes following laparoscopic repair of uterine tears reported by Diekstall et al 2020 (EVE - Lichlingen)

Answer 73

3 mares presenting 1-3d post partum w classic CSs

All tx laparoscopically; 1 w hand assisted technique, 1 w extra-corporeal knots and 1 w barbed suture

2/3 alive at 12 months. 1/2 delivered a live foal 2yrs PO. 1 died 3mo PO of unknown cause

Question 74

PO management following uterine tear

Answer 74

Abdominal lavage for 2-3d PO and uterine lavage beginning 1d PO continuing for 3-4d

Allow at least 2 months before being re-bred, but ideally left until the following breeding season

Question 75

Risk factors and clinical features of peri-parturient haemorrhage

Answer 75

• Haemorrhage can occur pre (rare) during, or post partum; usually within 24hr
• Haemorrhage can occur into the abdomen, the broad ligament or the uterus
• Usually occurs in older, multiparous mares: atrophy of vascular smooth muscle (tunica media) & fibrosis of the wall (tunica intima) have been identified as predisposing factors, w disrupted/calcified internal elastic lamina. May be assoc w age-related ↓ serum copper
• NB: Bleeding @ prev foaling does not ↑ risk further (contradicted on VetStream)
• Rare in maidens

Question 76

CSs of peri-parturient haemorrhage

Answer 76

• Pale mms
• Weak/thready pulse
• Tachycardia (often >100bpm)
• Anxiousness
• Sweating
• Colic with broad ligament haematoma
• Shock & sudden death
• Can see swelling on 1 side of the perineum 24-48hr post foaling
• Uncommon to see external bleeding (intra-uterine haemorrhage less common than BL or intra-abdomial)
• Occasionally subclinical - found at first post foaling exam

Question 77

Potential vessels involved in peri-parturient haemorrhage

Answer 77

• Uterine artery most commonly (middle uterine artery)
• External iliac
• Utero-ovarian
• Utero-vaginal (unilateral vulval swelling…?)
• Internal pudendal
• Other less common incl. internal iliac artery (n=1), and caudal mesenteric artery (n=1)

Higher propensity for vessels to bleed on the right. Dt position of the caecum? displaces uterus to left → ↑ tension on right uterine aa

Question 78

Dx of peri-parturient haemorrhage

Answer 78

1. CSs of shock
2. Rectal palpation - large firm mass in the broad ligament; don’t repeat once dx as can exacerbate bleeding
3. US +/- abdominocentesis for haemoabdomen

Question 79

Management & prognosis for peri-parturient haemorrhage

Answer 79

Management

1. Avoid excitement, keep in quiet, dark area and avoid stress (eg removing the foal). No transport
2. Restoring CV volume - volume expansion with colloids and crystalloids to maintain circulating volume & tx shock (beware can ↑BP and dislodge clot but usually have to treat; don’t over-expand clinically stable animals). Avoid hetastarch (fibrinolytic). Once recussitated, maintain low/normal BP to ↓risk of dislodging clot
3. Blood transfusion - often required; do if PCV <15% at 12-24hr (NB won’t △ acutely). Ideally X-match, otherwise obtain from large healthy donor. Not suitable for volume expansion as given slowly but req. for oxygen carrying capacity. Can auto-transuse if intra-ab haem → sterile collection in ACD and re-administer IV. NB remember NI in subsq pregnancies post transfusion
4. Pain control - NSAIDs +/- opiods etc
5. Enhancing haemostasis - eg aminocaproic (2-40mg/kg IV) or tranexamic acid (5-25mg/kg IV)
6. Avoid repeated rectal/vaginal exams unless absolutely necessary
7. Preventing infection - BS ABx
8. Surgery is CONTRAINDICATED; need to differentiate other dz eg uterine rupture (can also get haemoabdomen), bladder rupture
9. Some controversy over ACP: ↓BP may ↓rate of bleeding but can precipitate shock if sufficiently hypovolaemic; prob best avoided
10. Corticosteroids (anti-shock dose 1-2mg/kg IV) to stabilise endothelial membranes
11. Oxygen insufflation

Prognosis

Guarded to poor. Many die at initial bleed or in the subsequent days. Biggest cause of peri-partum death in several studies. Contradicting literature on risk of fatal haem in subsequent pregnancies;

Some Suggestion that SURVIVING MARES ARE AT INCREASED RISK OF FATAL HAEMORRHAGE AT SUBSEQUENT PREGNANCIES, but other studies suggest that 49% affected mares will produce at least 1 more foal

Question 80

Ddx for colic in the pregnant or peri-parturient mare

Answer 80

INTESTINAL

• Large colon torsion
• Large colon impaction
• Small intestine incarceration through mesenteric rent
• Rupture (caecum/colon esp)
• Mesocolon tear with segmental ischaemic necrosis of the small colon
• Rectal prolapse
• Uterine tear +/- bowel prolapse

EXTRA-INTESTINAL

• Placental expulsion & uterine involution
• RFM
• Uterine torsion
• Uterine inversion/invagination or prolapse
• Uterine rupture
• Peri-parturient haemorrhage (broag ligament most painful, intra-abdo ususally sudden death)
• Ruptured bladder

HERNIAS

• Prepubic tendon rupture
• Body wall ruptures
• Diapgragmatic hernia

Question 81

Indications for elective caesarean in the mare

Answer 81

• Compromised birth canal dt previous pelvic fracture or soft tissue injury within the reprotract
• Previously difficult dystocia
• Previous severe uterine artery haemorrhage
• ? permanent trach? dt decreased abdo pressure. May not all need C-se but need to be assisted and option for C-secion ideally

Question 82

Methods of timing elective C-sections

Answer 82

1. Surgery performed when the mare enters stage 1 labour
2. Measurement of milk electrolytes - at term Ca²⁺ rises to >10mmol/L and Na⁺: K⁺ reverse; K⁺ increases to ≥30-35mmol/L and Na⁺ decreases to ≤20-30mmol/L. Electrolyte scoring system has been developed (see table, score >35 points indicates safe for parturition)
3. Milk pH - decline around the time of parturition - majority of mares with a pH <7 have been shown to foal within 24 h (still in its infancy)

Question 83

Indications for emergency C-Section

Answer 83

1. For delivery of a live foal where assisted or controlled vaginal delivery has failed to deliver the foal within 15-30 mins. Most common reason is foetal malposition/malpresentation/malposture. Some foetal positions (eg transverse, dog sitters) are seldom born vaginally so caesarean should be performed soon in the course of labour to achieve best outcomes for both mare and foal
2. Uterine torsions presenting at or very close to term, or where the mare is the key priority (ie not leaving to foal and risk incisional dehiscence shortly after sx)
3. Foetal abnormalities incl emphysema, foetal monsters, severe arthropgryphosis (usually carpal) & other deformites preventing foetal manipulations and exit via the birth canal

Question 84

Surgical procedure for caesarean

Answer 84

• GA; ventral midline clipped and prepped while attempting controlled vaginal deliver
• Dorsal recumb +/- horse tilted slightly toward the surgeon
• Make 35-40cm ventral midline incision beginning at or 10cm caudal to the umbilicus
• Locate and exteriorise the gravid horn which usually contains the hind limbs of the foetus
• Seromuscular stay sutures either end of proposed incision can help manipulation and prevent abdominal contamination
• Incision is made through the uterine wall & chorioallantois from foetal hocks to fetlocks/feet
• Make large hysterotomy - often tears during foetal extraction
• If the hind limbs are not present in a horn, the uterine incision is made at the base of a horn and body of the uterus with the uterus in the abdomen; this may lead to significant abdominal contamination
• Incise amnion, exteriorise and grasp foal. May need chains above fetlocks. Need assistants to lift and take foal
• Clamp umbilicus close the body of the foal; cut between 2 clamps. Maternal clamp can be left in the uterus for later removal (if plastic)
• The chorioallantois is separated from the endometrium for 3-4cm along the hysterotomy incision. Can be removed in entirety if it separates easily, however usually well attached
• Incised edge of the uterine wall bleeds profusely; should place a haemostatic suture line ‘Whipstitch’ → continuous Ford interlocking along the edge with individual vessel ligation where req. Although some texts suggest no difference in outcome +/- whipstich, it really should be done - negligent not to if bleeds to death
• Uterine closure in 2 layers - USP 1 or 2 absorbable suture. Appositional then inverting pattern necessary in the outer layer to provide a serosa-to-serosa seal. Repro book = USP 2 or 3 Vicryll Lembert in the first row (better haemostasis than Cushing) and Cushing oversew (Lembert bites would be far away from incision during second row)
• 20IU oxytocin once closed
• Abdominal lavage and routine closure

Question 85

Approaches for terminal caesarean

Answer 85

1. Ventral midline - need to prop in dorsal (depends on facilities)
2. Low flank (Marcenac) - caudoventral aspect of the last rib to the flank fold
3. Flank (not easy to do normal PLF incision)

Question 86

Caesarean aftercare

Answer 86

• Care re RFM - can use IV OT (40IU in 1 L) over 30-60mins. Manual removal may be req.
• Uterine lavage SID 3-4d depending on RFM status
• ABs and flunixin 3-5d PO. IVFT if necessary (+/- blood transfusion(s) if indicated)
• Care re POI (intestinal manipulation or bruising)
• Diet should be laxative = grass preferable
• 30d box rest then small paddock if incision OK

Question 87

Possible complications following caesarean

Answer 87

• Peritonitis rare after c-section - may be more likely after protracted vag delivery?
• Care re pre-GA epidural → may need assistance to stand
• Older mares (>10yrs) esp TB ↑ risk of long bone fracture (esp tibia)
• Risk of RFM ↑ after c-section (incl. elective - dt removal of foal before onset of 1st stage labour) and dystocia. RFM also more likely after delivery of live foal vs dead foal
• Blood loss/req. for transfusions
• Incisional complications
• Care re high volume lavage - can disrupt hysterotomy. Probably better to do sterile 5L lavage
• Uterine tears → peritonitis
• Cervical tears → decreased fertility.
• Vaginal tears → rectovaginal/vestibular tears, perineal lacerations, abscesses.
• PO uterine adhesions (allow gentle walking, some advocate daily rectal palpation but probably pointless)

Question 88

Expected outcomes following caesarean for both mare and foal

Answer 88

Mare: Survival >80% - approaching 100% for elective c-section. (61-100% depending upon cause of dystocia).

Dystocia overall: 82-91%. Fetotomy: 90-96%. CVD: 94%. C-section: 82-89%.

NB: TB may req 6 wks recovery before natural cover

Foal: Dystocia overall: 11-44% initially (approx 30%). Survival to discharge: 5-30%. CVD: 32%. C-section: 0-31%

Duration of dystocia has huge effect on outcome. Survival rate ↓ rapidly if > 45-60mins between rupture of chorioallantois and delivery, ∴ when foal alive - req. fast assessment & decision making

In 1 study: Foals that survived dystocia were all delivered within 90 mins. 154 mins was the longest time recorded for delivery of live foal in another study. No foal survived to discharge following dystocia >162mins.

NB: Following live birth, most common reason for euthanasia or foal death was malformation or neonatal maladjustment syndrome

GENERAL RULE:

For every 10 mins after 30mins - risk of foal mortality ↑ by 10%

Retrospective analysis of 95 mares undergoing cesarean section yielded an 84% mare survival rate and a 35% foal survival rate

Fertility: Pre-dystocia live foaling rates vs post-dystocia live foaling rates: 84% vs 62%

Mares breed the same year following C- section had 51% preg rates and 41% foaling rate compared to 69% and 61% respectively in the second year

Decreased fertility can be caused by uterine adhesions, inability of uterine wall to adapt to foetal growth, focal endometrial destruction, trauma and damage to other area of the reproductive tract.

Question 89

Relationship between foetal position and deformities

Answer 89

By 8months gestation, almost every foetus in anterior longitudinal presentation; posterior longitudinal = abnormal. Anomolies proportional to presentation:

Posterior → foetal malformation 20x more likely

Transverse → foetal malformation 200x more likely

May also be the case with malposture eg. Head retained (neck flexion) → neck vertebrae forced to ossify w neck flexed → wry-neck

When severe enough → c-section.

Px may appear dismal but spont recovery is poss! -> Delay euthanasia until obvious

Body pregnancy - likely has similar issues but no clear link in the literature

Question 90

Definitions of presentation, position and posture WRT the foetus in the uterus

Answer 90

Presentation: Orientation of fetal spinal axis to spine of mare. Described as longitudinal or transverse. Portion of fetus entering vag canal 1st; Cranial/caudal or ventral/dorsal ∴ cranial or caudal longitudinal OR ventro or dorso-transverse

Position: Relationship of fetal dorsum (in longit presentation) or head (in transverse presentation) w mare’s pelvis: ∴ dorsosacral or right/left dorsoilial or dorsopubic or right/left cephalo-ilial

Posture: Relationship of fetal extremities (head/neck/limbs) w its body. Most common cause of dystocia - difficult to correct as v long head, neck, limbs of foal

Question 91

Key points on vaginal bleeding during pregnancy

Answer 91

Placental detachment & impending abortion NOT assoc w haemorrhage from cervix (unlike human), ∴ blood at vulval lips usually unimportant & most likely dt vaginal varicosities (or occas vag trauma)

Speculum exam to confirm (scrupulous asepsis) & rule out urinary tract pathology

Varicose vein etiology unknown - ↑ bloodflow dt pregnancy oestrogens may contribute to distension

Occassinally rupture - haemorrhage rarely severe. Vessels can be 4-5mm diam - usually dorsocaudal vagina

Can be ligated or LigaSure. Laser and cryotherapy also described

Question 92

Vaginal trauma during foaling - dx & management

Answer 92

Some can be fatal with profuse haemorrhage

If profuse & cannot be ligated, create large tampon from roll of CW & use as pressure bandage

Cover w petroleum jelly + oily ABs prep to help removal

W vaginal haematomas, may have difficulty defaecating; use laxative diets until haematoma ↓ in size

Question 93

Predisposing factors and clinical signs for prepubic tendon rupture & abdominal wall rupture/hernia

Answer 93

Predisposing factors: Dz of the heavily pregnant mare. Incr risk w hydrops, twins, foetal giants. More commonly affects older, multiparaous mares. Rare in maidens. Draft breeds & SBs overrepresented (same breeds as inguinal hernias)

CSs:

• Abdominal pain
• Change in ventral abdo shape or excessive ventral/ventrolateral oedema - from mammary to xiphoid - makes palpation of defects difficult. Most severe & rapidly progressive for PPT rupture
• PPT or rectus abdominus m. most common. External, internal abd oblique & transverse abdominal mms may also be involved. May have POP of body wall
• ↑ HR, ↑ RR, distress (HR 80+ usualy. NB HR in late gestation upto 60bpm)
• With PPT rupture, may be reluctant to move, sawhorse stance characteristic;
• characteristic stance as the pelvis tips cranially without stabilisation by the abdominal wall. Fank is poorly defined & lordosis develops w elevation of tubera sacrale, tubera ischia & tailhead
• Mamm glands may be displaced cranially or flattened & their secretions may be bloody
• Often haematoma assoc with the tear (can → abscess)

Question 94

Anatomy of the pre-pubic tendon (PPT)

Answer 94

Extends ventrally from the brim of the pelvis; it runs along the pectin of the pelvis from 1 iliopubic eminence to the other & is comprised of the linea alba and the insertion of the rectus abdominis muscle, which crosses such that fibres from either side of midline insert onto the PPT

It is the origin of the pectineus mm (running from iliopubic eminence to the pelvic symphysis) & origin of the gracilis mm, running from cranial PPT to the inner thigh.

Complete rupture of the PPT leads to complete loss of support to the ventrolateral abdominal wall

Question 95

Main ddx for prepubic tendon rupture

Answer 95

1. Ventral/ventrolateral body wall rupture (mostly rectus abdominis but can affect any abdo mm)
2. Hydrops (hydroallantois or hydroamnion); also presents w progressive abdominal enlargement & accompanying ventral oedema

Question 96

Management/decision making in PPT rupture/ventral body wall rupture

Answer 96

Management will vary case by case depending on priorities (mare vs foal), severity (pain & ability to control it) and case progression

If the mare is the priority - if condition deteriorating, induction of abortion/parturition

If the foal is the priority - aim is to maximise gestation length until the foal is mature enough for delivery, since this occurs mainly in the last 10d gestation. Don’t induce unless confident of foetal maturity

Conservative management (avoiding induction /caesarian) = providing supportive care until parturition occurs naturally at term → tx of choice if possible ie if pain is controllable and condition is slowly progressive

• Attempt to prevent further tearing. Confine. Use abdo support bandage (eg CM Equine hernia belt, care re spine pressure necrosis). NSAIDs (+ other analgesia if necessary) to ↓ inflam + pain +/- systemic ab’s to ↓ chance of abscessation. Continual assessment of fetus w electrocardiogram/US necessary. Reduce dietary bulk and promote soft faeces
• If there are signs of foetal stress/compromise → intervene either with induction (preferable) or C-section (less ideal - select if foetus mature or terminal C-section)
• Induction is usually preferable over C section, as often systemically compromised & pronounced oedema makes incisional complications common.

NB: late term mares can be induced w 100mg dex/day over 5-7 days, whic can ↑ viability and enhance foetal maturity

• Daily monitoring for foetal stress; presentation (transverse or posterior presentations indicating likely dystocia), foetal HR (with bradycardia of<60 bpm or tachycardia >120 indicating stress). Some foetal activity should be observed within 30 mins
• Foaling needs to be attended - no abdo effort. Can induce if deteriorating or confident of foetal readiness → use oxytocin at 5–10 IU IV, repeated if necessary in 20–30min (higher doses can be painful and rapid)

Surgical repair:

• Not possible in acute phase as tissue fragile
• May be possible in select cases post foaling when oedema is improved/resolved depending on size and location of defect (recommended 3-4 months post-foaling); scar tissue req’d to secure suture/mesh
• Can use direct suturing or mesh repair
• Generally not necessary small defects - many mares with abdominal wall defects can successfully carry further pregnancies, and foal successfully, with assistance
• Mesh complications incl. adhesions, chronic implant infection
• PPT rupture is NOT a surgical condition in the horse - surgical repair of PPR not documented in the horse. It is likely that no repair would have sufficient strength given the considerable tension of the ventrolateral abdominal wall in the horse. Re-breeding NOT recommended

Question 97

Expected px for PPT rupture

Px for ventral abdominal wall rupture/hernia

Answer 97

PPT rupture can be fatal -dt evisceration, rupture of a GI viscus or fatal haemorrhage as the uterus looses the support of the body wall

Mare & foal survival rate vary greatly

Mare - guarded-grave - 3/4 mares died in 1 study but 10/13 survived in another (2008).

Foal - survival depends largely on stage of gestation. Good if delivered at term/mature. Otherwise poor

Mares with PPT should NOT be re-bred

AW rupture: Many mares with abdominal wall defects can successfully carry further pregnancies, and foal successfully, with assistance. ET may be a good option

Question 98

Clinical signs of hydrops and clinical features

Answer 98

• Hydoallantois more common than hydroamnion - but both rare
• Present w rapid abdominal enlargement over a period of days to 1-2 weeks, usually w previously uneventful gestation.
• Typically occurs mid to late gestation (>7 months). Usually multiparous mares
• Signs of discomfort - difficulty walking, lying down and standing, weight-shifting, dyspnea, anorexia, decreased fecal output.
• Ventral edema (pitting).
• Hydroallantois typically causes the mare’s abdomen to be barrel shaped when viewed from behind, whereas hydroamnios may make the abdomen more pear-shaped.
• Spontaneous abortion of deformed fetus sometime occurs in late gestation although can be complicated by uterine inertia dt stretching of uterine mm
• In hydroamnios, craniofacial fetal abnormalities may result in abnormal swallowing resulting in decreased clearance of amniotic fluid.
• Fetus is not always deformed in cases of hydroallantois, but poss deformities incl. torticollic, hydrocephalus, scoliosis, cerebral/cerebellar hypoplasia
• May be assoc. with ventral abdominal hernias or prepubic tendon rupture

Question 99

Dx of hydrops

Answer 99

Hx & PE

Rectal examination - reveals an enlarged uterus with abnormal fluid accumulation making palpation of the faetus impossible in some cases (should be palpable in normal late pregnancy) (*NB uterine torsion will displace foetus cranially and make foetal palpation difficult). The uterus typically bulges dorsally above the pelvic brim.

US - Excess fluid in the allantoic sac (hydroallantois)/amniotic sac (hydroamnios). NB US doesn’t always facilitate differentiation of allantoic and amniotic fluid. Foetus may be alive or dead, may show signs of intrauterine hypoxia, eg decreased movement, bradycardia. May or may not be placental/cord edema or torsion, uterine rupture or abdominal or prepubic tendon rupture

Question 100

Management of Hydrops

Answer 100

Terminate pregnancy - Risk to mare from pressure on internal organs, hypovolemic shock, or ventral musculature or pre-pubic tendon rupture is high if pregnancy continues, and the viability of the fetus is poor anyway.

Use manual cervical dilation and rupture of chorioallantois. PG (2x6 h apart) may facillitate this.

Plus oxytocin; 2.5-5IU IV q20-30min.

Drain allantoic/amniotic fluid via a uterine drain tube or sterile nasogastric tube (may be as much as 100 l) during stage I of parturition. The goal is slow release of the foetal fluid to enable the vascular system of the mare to adapt, and try to minimise the risk of hypvolemic shock.

Assist delivery; will have uterine inertia dt myometrial stretch. May need caesar if the foal is very ascitic, but the foal will not be viable. The fetus is often alive at delivery, but is not expected to survive.

IVFT: used prophylactically and started pre-partum. Can use hypertonic saline (2 l IV) to treat hypotensive shock; follow with a minimum of 20 l IV fluids.

Corticosteroids: Dexamethasone 0.5-1 mg/kg to help prevent hypovolemic shock.

RFM and delayed involution common

Question 101

Outcomes for hydrops

Answer 101

PROGNOSIS - Guarded - intervention is essential to prevent rupture of the abdominal wall, prepubic tendon or uterus, or death of mare.

If future normal pregnancies are possible, advise use of a different stallion.

In cases where mare has suffered ventral musculature rupture, secondary to hydrops, if the rupture is limited enough that she can be returned to good general health without compromising welfare it may be possible to breed from her or by using her as an embryo donor in future.

Fair to hopeless for foal - depends on maturity of foetus and degree of peripartum hypoxia when delivery is induced; a live fetus may be delivered but often it is not viable.

Question 102

Key points WRT foetal in-utero kinetics

Answer 102

Rotation of foetus within amniotic cavity & rotation of amniotic sac w/in allantoic cavity → characteristic twisting of umb cord

By 5-7 mths horns contract and fetus confined to uterine body

Neuro signals in maturing inner ear may orient fetal dorsum along concave ventral ut w/ head towards cx

By 7 mths, acute angle between horns and body means fetus must be in dorsal recumb before HLs can gain entry

From 9 mths, HLs enclosed within gravid uterine horn + hooves reach tip by 10 mths

Fetus now ‘locked’ into cranial (anterior) presentation w dorsopubic position (dorsal recumb) (ie can’t rotate from approx 8mo gestation)

Likely explains why 98.9% delivered in cranial position; 1.% caudal position, 0.1% transverse position

Close to term, gravid horn containing HLs comes to rest on dorsal surface uterine body - body and horn form a U-shape tapering towards tip

Possible for HL hooves to be pushed so far caudally overlying fetal head (palpable per-rectum)

HL thrusts can push hooves caudally past cervix into rectogenital pouch

May explain acute colic episodes

Gel-like pads on hooves help protect placenta + ut but tears at tip of gravid horn still poss

Question 103

Events in normal parturition

Answer 103

• ↑ uterine tone in stage 1 pushes cervical star against cervix → gradual dilation
• Contractions may stimulate fetus to position itself for delivery → FL extension - The live fetus plays an active role in positioning ready for delivery and if weak/dead this is compromised.
• Cranial aspect makes purposeful movements into dorsoilial position & head + FLs extend
• FLs & neck usually will not return to flexed posn once extended by active fetus in stage 1 BUT fetlock flexion can occur if hoof catches on pelvic brim/vag mucosa (can progress to carpal flexion w expulsive efforts of the mare)
• NB: Dystocia w/ dorsopubic posn + flexed extremities suggests fetus compromised before/early in parturition eg placentitis or fetal infection - submit samples if stillborn
• Mare’s side to side rolling also thought to assist w foal positioning
• While cranial part of foal traversing birth canal, HLs remain locked in ut horn. Once stifles contact pelvic brim, HLs forced to extend and released from horn
• At time of delivery, cranial aspect of contracting ut is only 12 inches from cervix

Question 104

Principles of mutation (foetal manipulation) in dystocia

Answer 104

• Use rope behind ears/through mouth to secure head and ropes/chains to secure limd (pasterns advised but less likely to slip off in above fetlocks)
• Limited space in pelvic canal ∴ repulsion usually necessary for manipulations
• Tocolytics helpful (clenbuterol, isuxiprine)
• Care re trauma to the tract caused by yourself or prev intervention by O; most body tears are iatrogenic. Ideally confirm no rupture before pumping large quantities of lubricated fluid (latter may provide some uterine relaxation + may provide extra space to mutate malposture)
• Malposture of limbs/head most common reason for intervention; don’t deliver without correction, risk serious damage to mare/foal
• Potential foal injuries incl: rib fracture, bruised rib costochondral junc, haemarthrosis of shoulder joints, internal haemorrhage/ruptured viscus
• Ensure full cervical dialtion and no more than 3 people applying traction

Question 105

What is this?

How should it be managed?

Answer 105

‘Red bag delivery’

= premature placental separation and failure of the chorioallantois to rupture

More common in induced parturition and w fescue toxicosis

Chorioallantois should be ruptured & provide gentle traction (can lacerate cervix or precipitate fractured ribs if excessive)

NB foal likely experienced profound hypoxaemia. Rapid intervention necessary for survival and foal will be v likley to require intensive care +/- CPCR

Question 106

Principles of correction for transverse presentations

Answer 106

• Very difficult to correct. C-section best bet if the foetus is alive
• 1/1000 presented transversely but accounts for 10-15% of referral dystocias
• Higher incidence of foetal malformations dt lack of room. Neither horn fully expanded. 1/3 have significant FLD, ALD or vertebral malformations
• Ventro-transverse (limbs in pelvic canal) more common; care re twins. Can attempt controlled vaginal delivery & conversion to caudal presentation UGA
• Dorso-transverse very uncommon; C-section only option even if foetus dead

Question 107

Principles of correction for caudal/posterior presentations

Answer 107

• If soles of hooves facing upwards - either cranial presentation that has failed to rotate or in caudal presentation. Palpation of hocks confirms dx - only 1% present caudally (15% of hosp dystocia referrals)
• ↑ risk fetal hypoxia by compression of umb cord under thorax w caudal presentations. Cord rupture while head still in uterus can → fetal death
• Uncomplicated caudal presentation may only need supplementary traction (ie when HLs are fully extended in the pelvic canal)\
• Most caudal presentations → dystocia as synchronised rotation of body and extension of limbs does not occur
• Often dorsoilial posn + many postural abnorms of long HLs - usually bilateral
• Billat hock and hip flexion extremely difficult to correct in field - v ltd space in birth canal
• For flexed hocks - repel (can use Kuhns crutch but care re uterine trauma), attempt extension of HLs by dorsolateral rotation of metatarsus and caudomedial traction on distal limb
• Hip flexion (breech) v difficult to correct. C-section best option for both