Chapter 39 - Rectum and Anus Flashcards
1
Q
A
2
Q
What is the approximate length of the rectum in an adult horse?
A
The rectum is approximately 30 cm long in an adult horse.
3
Q
What factors influence the distance from the anus to the peritoneal reflection?
A
The distance from the anus to the peritoneal reflection is highly variable and is shorter in young horses and in horses with little body fat.
4
Q
How is the peritoneal part of the rectum attached dorsally?
A
The peritoneal part of the rectum is attached dorsally by the mesorectum, which is a continuation of the mesocolon.
5
Q
What forms the dilation in the retroperitoneal part of the rectum?
A
The retroperitoneal part of the rectum forms a dilation called the rectal ampulla, which has thick longitudinal muscle bundles.
6
Q
What structures enclose the anal canal?
A
The anal canal is enclosed by the internal anal sphincter, a thickening of the circular smooth muscle, and the external anal sphincter, composed of striated muscle.
7
Q
From where does the levator ani muscle arise, and what is its action?
A
The levator ani muscle arises from the ischiatic spine and sacrotuberal ligament. Its action overcomes the tendency of the anus to prolapse during defecation.
8
Q
Why are rectal tears considered life-threatening injuries?
A
due to the risk of peritonitis and endotoxic shock. The risk of a malpractice claim against the veterinarian is influenced by the standard of care applied after the tear.
9
Q
What are the minimal measures required to prevent iatrogenic rectal tears during examination?
A
Copious lubrication of the hand and forearm and adequate restraint of the horse, including sedation if necessary, are regarded as the minimal measures required to prevent iatrogenic rectal tears during examination.
10
Q
What causes most rectal tears resulting from palpation per rectum?
A
Most rectal tears caused by palpation per rectum result from rupture of the rectal wall as it contracts around the examiner’s hand or forearm and not from penetration with the fingertips.
11
Q
Which horse breeds, gender, and age groups are most prone to rectal tears?
A
Arabian horses, American Miniature Horses, mares, and horses older than 9 years are the breeds, gender, and age groups most prone to rectal tears.
12
Q
How are rectal tears classified based on severity?
A
Rectal tears are classified into four grades based on severity:
grade I involves the mucosa and submucosa,
grade II involves the muscular layer
grade III involves all layers except the serosa (grade IIIa) or mesorectum and retroperitoneal tissues (grade IIIb),
grade IV involves all layers and allows fecal contamination of the peritoneal cavity.
13
A
a) Grade I: disruption of mucosa and submucosa, while muscularis andserosal layers remain intact.
14
Q
A
Grade II: disruption of muscularis layers, while mucosa, submucosa and serosal layers remain intact.
15
Q
A
Grade IIIa: disruption of mucosa, submucosa and muscularis layers while serosa remains intact
16
Q
A
Grade IIIb: all 4 layers of the rectum
are disrupted dorsally into the mesocolon, but the mesocolon remains intact.
17
Q
A
Grade IV: all 4 layers are torn resulting in direct
communication between the rectal lumen and the peritoneal cavity
18
Q
Where do most rectal tears involve the dorsal aspect of the rectum (cm from anus), and how are they oriented?
A
Most rectal tears involve the dorsal aspect of the rectum, **located 4 to 60 cm from the anus**, and are oriented parallel to the longitudinal axis.
19
Q
The cause that appears to influence the size of the tear is ____(1w)
A
dystocia, with a median size of 25 cm in one study
20
Q
What is the initial treatment for rectal tears, and why is early diagnosis essential?
A
Early diagnosis is essential for successful treatment and to avoid legal repercussions. Initial treatment includes (1) reduction of activity of the rectum,
(2) gentle removal of feces from the tear and rectum,
(3) treatment of septic shock and peritonitis, and
(4) administration of epidural anesthesia and packing of the rectum
21
Q
What materials are used for rectal packing to prevent conversion of a grade III to a grade IV tear?
A
Rectal packing is done using a 7.5-cm stockinette filled with 0.25 kg of moistened rolled cotton, sprayed with povidone-iodine, and lubricated with surgical gel.
22
Q
Which medications are administered for treatment of rectal tears?
A
Flunixin meglumine (1.1 mg/kg IV BID), sodium or potassium penicillin (22,000 IU/kg BW IV QID), gentamicin (6.6 mg/kg IV SID), and metronidazole (15 mg/kg PO QID) are administered for treatment.
Intravenous fluids are required to treat shock.
23
Q
How can rectal tears be assessed and treated after initial first aid?
A
Rectal tears can be assessed through epidural anesthesia, xylazine (0.1-0.2 mg/kg), butorphanol tartrate (0.1 mg/kg IV), or butylscopolamine bromide (0.3 m/kg IV) slow, followed by lidocaine enema (12 mL of 2% lido in 50 mL tap water) or lidocaine jelly application.
Rectal tears are treated with appropriate antibiotics, and daily inspection and careful evacuation of the rectum may be sufficient for grade I and II tears.
24
Q
Which grades require surgery?
A
Grade 1 & 2 tears RARELY require sx
*Grade 1 respond well to abx (TMPS),flunixin, mineral oil & dietary changes i.e. bran mashes,moistened pellets, or grass, to reduce fecal volume and soften the consistency
*Grade 3 can require sx BUT medical management can be successful (less ££)
Mair 2000 EVJ Supp –6/8 tx successfully with medical management grade 3b tearsALL developed septic peritonitis,3/6 developed rectal diverticulum in the tear – WITHOUT apparent C/S (onlymanually evacuate rectum if the tear becomes impacted)
*Full-thickness tears into retroperitoneal space maybe treated with manual evacuation of feces, abx, fecal softener, & packing with gauze soaked in antiseptic solution until defect fills with granulation tissue *
25
What are the repair techniques?
1.TEMPORARY INDWELLING RECTAL LINER
2.COLOSTOMY: LOOP COLOSTOMY
3.COLOSTOMY: END COLOSTOMY
4.COLOSTOMY REVERSAL
5.TEMPORARY VS PERMANENT COLOSTOMY
6. LAPAROSCOPIC REPAIR
7. DIRECT SUTRE
Faecal diversion procedures are 2 types of colostomy:
Loop - stoma in antimesenteric tenia of SC withouth completly transect the bowel
End colostomy - involves complete transection of SC
26
What is the purpose of bypass procedures in rectal tears, and how do they prevent complications?
Bypass procedures, such as Temporary Indwelling Rectal Liner (TIRL) and colostomy, divert feces away from grade III and grade IV rectal tears, preventing contamination, impaction, tear enlargement, and progression of peritonitis.
27
What is the procedure being performed?
Fig 8: Placement of an indwelling rectal liner in the distal small colon(a, b) with application of acircumferential ligature and simple interrupted retention sutures (c) and oversewing the circumferential ligature with an inverting continuous Lembert suture pattern (d).
28
How is a Temporary Indwelling Rectal Liner (TIRL) constructed, and what materials are used?
A temporary indwelling rectal liner can be assembled usinga plastic rectal prolapse ring (ProFix Tube), No. 5 Dacronsuture, a heavy plastic palpation sleeve or arthroscopiccamera sleeve (Video Camera Cover), a rubber band andcyanoacrylic glue (Super Glue).
To assemble a rectal liner, the plastic rectal ring must becut to a length of approximately 5–7.5 cm.
Small holes, 2 mmin diameter, are then drilled into the ring at one end of thecentral groove in a circumferential manner, approximately4 mm apart.
Dacron suture is threaded through the drill holesto act as an anchor for securing the rectal liner withinthe lumen of the small colon.
After removing the handportion of the sleeve, the wrist portion of the sleeve isfastened to the rectal ring using a rubber band and cyanoacrylic glue and is inverted after attachment toprotect intestinal mucosa from irritation by the plastic of therectal ring (Fig 6).The indwelling
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Figure 7 - Placement of an indwellingrectal liner in the distal small colon.
Fig 6: Assembly of a temporaryindwelling rectal liner by cutting oneend of a porcine rectal ring to alength of 5–7.5 cm and drillingadditional holes into the ring (a andb), threading the holes with No. 5Dacron suture (c), applying a rectalsleeve (after the hand has beenremoved) around the rectal ringand holding it in place with a rubberband (d), gluing the rectal sleeve tothe rectal ring with cyanoacrylicglue (e) and inverting the rectalsleeve over the rectal ring (f).
30
Once you have the indwelling rectal liner ready what is the procedure?
GA - DR - The indwelling rectal liner is manipulated into placethrough a ventral midline celiotomy after an assistant passesthe ring and sleeve through the anus and into the proximalportion of the rectum.
The surgeon manipulates the rectal ringintra-abdominally until it is in the most distal portion of the smallcolon orad to the rectal tear.
Using No. 3 chromic gut, acircumferential ligature is applied around the small colonat the level of the central grove of the rectal ring to constrictthe serosal surface.
4 equidistant simple interrupted retention sutures ofNo. 3 chromic gut are placed around thecircumference of the small colon, incorporatingthe circumferential ligature, the small colon wall and theDacron anchor sutures (Fig 7).
Serosal surface is apposed over the circumferential suture with 3-0 polydioxanonesuture in an inverting suture patterncontinuous Lembert pattern (Fig 8).
PF enterotomy
Flush and cleaning of the SC with hoose directed thorugh ring and liner from anus
31
What is the goal of the 4 equidistant sutures in TIRL?
*four retention sutures help maintain the ring in a coaxial relationship with thesmall colon so that it doesnot twist and obstruct the lumen
32
How does the circumferential suture function in TIRL, and when is it expected to cut through the rectal wall?
The circumferential suture in TIRL prevents passage of the ring and liner for approximately 9 to 12 days, allowing time for the apposed colon walls to heal. It is expected to cut through the rectal wall by this time.
33
What are the complications of temporary indwelling rectal liner (TIRL)? What can you do to prevent?
***tearing of the sleeve**
retraction of the sleeve into the rectum and uncovering the tear,
and formation of a **rectoperitoneal fistula**
*Mineral oil post op** soften feces and prevent impactionat the prolapse ring
34
When do you perform direct suturing?
Because a grade III tear often progresses to a grade IV tear, direct suturing of these tears may be indicated
Direct suturing is very difficult if tears are notlocated close to the anus because visualisation of the tear isoften poor and manipulation of instruments within the rectummay be difficult because of limited surgical access
Repairs made by direct suturing are oftenperformed blindly.
Elongated instruments, such as the Deschamps needle and a rectal speculum have beendesigned specifically for repair of rectal tears, but may not beavailable in all referral hospitals because they are infrequently used and expensive.
Elevating the tail after caudal epiduralanaesthesia may aid in enlarging the anal orifice, improving access --> ballon of rectum allows better space for suture
A rectal tear that cannot be accessedthrough the anus might be repaired through an antimesentericenterotomy via a ventral midline celiotomy.
35
Figure 39-1. Impaction of feces into a grade IIIb rectal tear (a), causing progressive enlargement of the perirectal space and bacterial leakage across the peritoneum (b), swelling of the rectal wall (c), and small colon impaction (d). (From Freeman DE, Richardson DW, Tulleners EP, et al. Loop colostomy for management of rectal tears and small colon injuries in horses: 10 cases
36
Figure 39-2. Placement of a temporary indwelling rectal liner to divert feces from a rectal tear. The expanded view demonstrates the construction of the liner and the method of securing it in place. 1, Tear; 2, rectal liner; 3, rectal prolapse ring; 4, Dacron anchor suture; 5, circumferential suture; 6, retention suture; 7, interrupted Lembert suture.
37
Figure 39-3. (A) View through the transverse section of the abdomen shows the placement of the loop in the body wall. (B) Loop colostomy created with a double-incision technique with the high flank approach (broken lines) and placement of the stoma in a small low flank incision. The left opening (1) is the orad opening, and the right opening (2) is the aborad opening through which the aborad part of the small colon is flushed to prevent atrophy. (Redrawn from Freeman DE, Richardson DW, Tulleners EP, et al. Loop colostomy for management of rectal tears and small colon injuries in horses: 10 cases [
38
Suture should be long for direct repair of rectal tears why?
Suture used for direct repair of rectal tears should be longenough to allow knot tying outside the rectum, have lowmemory, resist stretching and resist faecal digestion.
Large-diameter suture should be used as small-diameter suturetends to cut through friable tissue edges
39
What type of suture is not recommend for direct repair?
Chromic gut is not recommended for direct repairs because ittends to stretch.
Simple interrupted or cruciate suture patternsare preferred over a simple continuous suture pattern becausecontinuous patterns tend to reduce luminal diameter(Freeman 2012).
40
What are the considerations in choosing the location for a loop colostomy, and why is a double-incision loop colostomy used as a standing procedure?
Exploration of the abdomen through the ventral midline is necessary if the horse has a surgical colic
that preceded the tear, if intraabdominal repair of the tear is considered feasible, or if the surgeon elects to empty the large and small colons to reduce stress on the colostomy and risk of impaction.
The double incision technique is ideal as a standing procedure, because it allows placement of the colostomy in a small but secure incision in the ventral body wall
colostomy should not be placed in the anesthetized horse for the following reasons:
(1) accurate placement ofthe stoma is difficult because muscle layers shift and landmarksbecome distorted in the recumbent horse compared with thestanding horse;
(2) it is expensive; and
(3) dehiscence ofthe stoma is a risk of rough anesthetic recovery
41
42
The loop-colostomy technique is preferred over the end-colostomy technique WHY?
*Loop-colostomy involves creating enterotomy incision stoma through antimesenteric taenia without resecting completly the SC
*EASIER and QUICKER to construct and reverse
43
Why is the loop colostomy technique preferred over the end colostomy, and what advantages does it offer?
The loop colostomy is preferred due to its ease of establishment, quick reversal, and prevention of fecal passage into the aboral end. Advantages include gravity assistance, complete fecal diversion, and access for daily flushing to prevent atrophy.
44
When should you decide to go for colostomy?
When the tear envolves **more than 25% of the circumference** of the rectum
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Loop colostomy - What is the difference between 1 single incision colostomy and double incision colostomy?
Single-incision colostomy involves placing the stoma in the same incision used to explore the abdomen and prepare the colon loop, whereas a double incision colostomy involves a separate flank incision for the stoma
46
What does loop colostomy consist?
**The loop colostomy** consists in placing the opening to the oral and aboral segment of colon for daily flushing (to prevent the atrophy of that segment) in a stoma created in left low flank. Failure to flush the aborad segment causes atrophy.
47
What are the abdominal approaches to create the loop colostomy?
Colostomy approach can be performed via
- left high flank
- left low flank
- ventral midline incision with advantages and disadvantages.
48
When do you need to perform a ventral midline?
sx colic that preceded the tear, ifintraabdominal repair of the tear is considered feasible, or if the surgeonelects to empty the large and small colons to reduce stress on the colostomyand risk of impaction
*BUT COLOSTOMY IDEALLY NOT DONE UNDER GA
49
With single-incision colostomies, incorporation of the colostomy inthe abdominal closure weakens the body wall repair and makesthe ventrally placed stomas, such as the low flank and ventralmidline placements, prone to prolapse and herniation
50
Figure 39-4. Loop colostomy placed in the low flank by a double-incision technique as a standing procedure 2 days earlier. Congestion in the mucosal shelf separating the orad and aborad parts of the small colon is typical for this stage.
51
Figure 39-5. Loop colostomy placed in the low flank by a double-incision technique as a standing procedure, 60 days later (horse is not that shown in Figure 39-4). The stoma is mature and healed to the surrounding skin; the mucosal shelf is evident as a small bulge in its midpoint.
52
Describe the procedure
Dobule-incision loop colostomy
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Where can you apporach if is double incision?
**High flank** to prepare the colon loop and guide it to separate low flank incision
**Low flank i**ncision midway between the flank fold and the costal arch at same level as the fold
54
Explain how you would construct regardless the approach the stoma for loop colostomy
The stoma is made in a segment of SC orad to rectal tear
At least 1 maway from the rectum
*Exteriorize the colon and SC isfolded to form a loop
*2 arms of the loop are sutured together 8 cmc ontinuous Lembert pattern size 0 polydioxanone midway between the mesentericand antimesenteric teniae.
*As the suture line approaches the end loop it should be close to the mesocolon so that antimesenteric band is outermost
55
How do you perform bypass with double incision loop colostomy?
**Ideal as standing procedure** - allows placement of the colostomy in a small but secure incision in the ventral body wall
**Highflank incision** - prepare colon loop, guide it intoa separate low flank incision, midway between the flank fold (just in front ofthe stifle) & the costal arch, and at the same level as the fold
*Fecal balls can drop away from thestoma without contacting and soiling the abdominal skin
**Lowflank incision** (8-10 cm long) - extends throughall layers, with deep dissection guided by a hand through high flank incision- angled dorsad from cranial to caudalby 20-30 degrees **Small transverse incisions** are made in muscles & fascia to eliminate constricting bands that could restrict fecal passage
56
How do you create the double loop colostomy?
**1st the high flank incision** is made to prepare the colon loop - midway between the flank fold (just in front of the stifle) and the costal arch
2nd incision of **8 cm long in the ventral flank** through all layers - same level as the fold flank **angled dorsad from cranial to caudal by 20 to 30 degrees**
The sutured loop of SC is manipulated until it **protudes from skin 5 to 8 cm**
**Stoma** - at least **1m from rectum** –SC can be easily exteriorized for colostomy reversal
This **segment of SC is folded** = loop, 2arms of the loop are sutured together **with an absorbable material** in a **continuous Lembert pattern for 8-10 cm**, midway between the mesenteric & antimesenteric teniae (if not done before under GA)
*Prepared loop of SC - **oral segment** must be **cranioventral** in the incision & **antimesenteric tenia projects** beyond the skin by at least **3cm**
**Seromuscular layer** of loop is sutured to abdominal muscles & fascia (several interrupted sutures of 0 or 2-0absorbable) **6-8 mm apart**
*CARE – do not puncture/occlude **mesenteric vessels**
*To form the stoma - **8-cm incision** made along exposed antimesenteric tenia of the colon
Full thickness cut edge folded back & sutured to skin with simple-interrupted sutures of **2-0 nylon/polypropylene** to form the stoma
*Stoma = same size as SC lumen
Fecal drops fall directly in the floor without contacting the abdominal wall and skin;
57
If your stoma is large and loose what can cause?
Herniation and prolapse
58
If general anesthesia is required when should it be performed? before or after colostomy?
BEFORE this stage of the surgery should be completed as needed before the colostomy is made.
59
If you prepared the loop during ventralmidline approach how do you proceed?
The loop of small colon can be prepared during the ventral midline surgery with **heavy retrieval suture (size 2 nylon)** being placed on the **antimesenteric band**.
The two ends of the retrieval suture are placed on a **long needle**, and each end is directed from within the abdomen **through the body wall** at the **skin site marked preoperatively**.
The suture is tied without tension atthis site to guide subsequent dissection to the small colon.
60
End colostomy how do you perform?
For the end colostomy, the **colon is transected**, the **aborad segment** is **closed by the Parker-Kerr method**
- and the **orad end is incorporated** into the **bodywall** as for the loop colostomy.
The aborad segment tends to** atrophy,** so its diameter and length may become **reduced by 50%**.
This makes colostomy reversal by future anastomosis difficult and may cause anastomotic impactions and dehiscence.
Because only one segment of small colon is inserted through the body wall, an end colostomy might be preferable for the rare horse that requires a permanent colostomy
61
Under what circumstances might a **permanent colostomy** be considered, and what are the concerns associated with it?
A permanent colostomy might be considered for cases where the **aboral segment cannot be reversed** due to permanent changes - **SCC** in one mare describe. Concerns include lack of experience, durability, and **increased risk of prolapse or herniation.**
62
What is the purpose of daily flushing in loop colostomy after granulation, and how does it contribute to postoperative management?
Daily flushing exercises the aboral part of the small colon, preventing atrophy and reducing the risk of anastomotic complications after colostomy reversal.
63
What anastomosis technique is typically used for colostomy reversal, and why is the stapled side-to-side technique not recommended?
A **single layer of interrupted Lembert** sutures is typically used for anastomosis. The stapled side-to-side technique is not recommended due to the **risk of septic peritonitis, adhesions, and anastomotic complications.**
64
What is the role of antibiotics and laxatives in the aftercare of colostomy, and what dietary recommendations are made postoperatively?
Antibiotics and laxatives are continued for 3 to 5 days in aftercare. Horses are held off feed or fed grass and alfalfa hay at half the usual amounts for the first 2 to 3 days. Petrolatum-based ointment is applied to protect the stoma.
65
What is the expected **time frame** for **granulation** of the **stoma in loop colostomy,** and how is the aboral loop exercised during this period?
Granulation of the stoma occurs after **5 to 7 days.** The **aboral loop is exercised by daily flushing with warm water** through a garden hose, starting when the tear has granulated.
66
How/when is colostomy reversal performed, and what are the considerations during stoma resection and anastomosis?
Colostomy reversal is **performed 6 weeks** or more after the colostomy.
The **stoma is resected en bloc**, and a colonic **anastomosis** is performed **through** the resulting **flank incision**. Considerations include transecting the aborad segment along an acute mesenteric angle.
67
Describe the colostomy reversal technique
**GA - RL** recumbency, the **stoma is resected en bloc,** and a **colonic anastomosis** is performed through the **resulting flank incision.**
Even if the colon is not penetrated during dissection, **incisional infection** is a **common complication** of stomal resection.
For anastomosis, the **aborad segment** is transected along amore **acute mesenteric angle** than the **orad segment to correct** for a slight reduction in diameter.
A single layer of **interrupted Lembert sutures** with 2-0 polydioxanone (PDS) is used for anastomosis (Figure 39-6), but other methods are also suitable.
The postoperative feeding, antibiotic, and laxative regimens aresimilar to those used after the colostomy procedure.
68
What suture material and technique are typically used for colostomy reversal anastomosis, and what complications are associated with the stapled side-to-side technique?
aborad segment is transected along a more acute mesenteric angle than the orad segment to correct for a slight reduction in diameter. A single layer of interrupted Lembert sutures with 2-0 polydioxanone (PDS) is typically used. The stapled side-to-side technique is associated septic peritonitis and adhesions
69
What is the concern regarding the durability of a permanent colostomy in horses, and what potential issues might arise during increased intraabdominal pressure?
Concerns regarding the durability of a permanent colostomy include a lack of experience, potential prolapse, and herniation during increased intraabdominal pressure, as seen during parturition and athletic activity.
70
How does the loop colostomy method prevent atrophy of the aboral segment, and what is the recommended approach when the aborad segment is missing or inaccessible in a broodmare?
The loop colostomy method prevents atrophy by allowing daily flushing of the aboral segment. If the aborad segment is missing or inaccessible in a broodmare, an end colostomy may be preferable to avoid the need for flushing.
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In direct suture you should use which hand?
What is the preferred suture size?
The **left hand is used for tears on the right side,** and vice versa, and gloves are not worn. The preferred suture is **size 5 Dacron, 100 to 150 cm long, with a 6- to 8-cm half-circle cutting** or trocar point needle placed in the middle of the suture
72
What are the types of pattern used in direct suture?
A **cruciate or simple-interrupted pattern** is used. With both ends of the suture outside the rectum, the needle is manually advanced to the tear. The **first bite is placed** in the **center of the caudal edge of the tear**, holding the needle with the thumb and first two fingers. The needle is inserted approximately **1.5 cm from the edge of the wound** and guided into the defect subserosally by the second or third finger
73
Where do you palce the first bite?
The first bite is placed in the center of the caudaledge of the tear, holding the needle with the thumb and firsttwo fingers.
The needle is inserted approximately 1.5 cm from the edge of the wound and guided into the defect subserosally by the second or third finger.
74
Once you place the first bite of suture in the caudal edge (1.5cm from edge) of the tear what is the next step?
The **needle is pulled through the tissue**, again **grasped with the thumb and first two fingers,** and then placed in the c**enter of the cranial edge**. This bite begins subserosally within the defect and exits **1.5 cm from the edge**. The third finger is used to guide the exit point and press the tissue onto the needle. The **needle** is subsequently **brought out the rectum**, leaving a single strand of suture in the tear with the other **end extending 10 to 15 cm aborad to the anal sphincter**. The suture is then clamped with a hemostat between the needle and the point of exit from the tear and the needle remains threaded on the orad half of the suture. An **assistant holds the clamped suture** to one side to close the defect into a transverse plane, and the **needle is carried into the rectum**. The suture is then passed **through both cranial and caudal edges of the defect in one bite using digital manipulation** as before, and **finally the needle is brought out the rectum**. The hemostat is released and the needle end of the suture is drawn through to form a **cruciate suture**. The **knots are tied outside the rectum** and **pushed inside with one hand while tension is maintained** on the suture with the other hand. Additional throws are placed to secure
the knot.
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What do you use the third finger for?
To guide the exit point and press the tissue onto the needle
76
When is direct suturing contra-indicated?
it is notrecommended to use this method of repair on tears that are **larger than half the circumference of the rectum** as this method of repair may significantly reduce luminal diameter.
77
If grade IV rectal tear is close proximity to the anus what can you attempt?
If a grade IV rectal tear is located in close proximity to the anus, **direct surgical stapling of the wound can be attempted.** Full-thickness **stay sutures **using **a heavy suture material** can be placed **craniodorsal** and **cranioventra**l to the** tear** to **intussuscept the rectum partially** and bring the tear close to the anus. **TA 90 Premium surgical stapler**
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What instruments are required for direct suture repair?
***Long-handled instruments** with pistol grips and **60 cm long rectal speculum** facilitate the rectal tear.
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What conservative option could you try if you cannot manage to achive the rectal tear for suture?
The wound can be left open and the defect packed with antiseptic soaked gaze to prevent fecal impaction and dissectio.
80
Figure 39-8. (A) Deschamps needles, showing the rightandleft-handed configurations with 20-cm needles (right)and the 45-cm needle that is suitable for rectal tears (left).(B) Close view of the end of a Deschamps needle. Thethreaded eye near the pointed tip allows easy retrieval ofthe suture without the need for complete penetration bythe needle. Once the suture is grasped at the tip of theneedle, the instrument is rotated backward out of the tissueand can be rethreaded for the next bite.abcABCFigure 39-9. (A) Method of inserting the Deschamps needle into therectum and guiding it to the tear while protecting the tissues with theright hand. (B) The Deschamps needle grasps both sides of the tear andpulls the suture through it as well. (C) Suture placement for a grade IVtear. a, Serosa; b, muscularis; c, mucosa.
81
What should be care and prevent when suturing?
*Care must be taken to prevent:
-lumen reduction
-the suture ends are cut long to facilitate their removal
-check sutures at 24- to 48-hour intervals
-remove sutures in 12 to 14 days.
82
Laparoscopic repair has some limitations what are they?
currently available instruments may be too short in somecases.
83
What was the surgical approach in laparosocopy?
The flank approach dependes on the side of the rectal tear. Right was used as the tear wason the right side, at the junction of the retroperitoneal reflection and small colon.
An assistant surgeon placed a hand per rectum to stabilize the small colon and present the tear to the surgeon for closure
The laparoscope was used to assess the peritonealcavity for fecal contamination and to guide placement of the suture line.
A single-layer, simple continuous pattern with size 0 polydioxanone was placed through to the submucosa, butexcluding the mucosa, with a handheld 18-cm Mayo-Hegarneedle holder.
*Ventral midline celiotomy then performed to lavage abdomen
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What is the postop considerations for laparoscopy?
- AB
- Laxatives (mineral oil 2-4L/450kg andmagnesium sulfate 1g/KG) continued for 3 to 5 days.
- Held off feed or feed grass and alfafa hayat half amount for first 2-3 days.
- Protect around the colostomy the skinwith petrolatum-based (vaseline).
- Cradles as most horses mutilate thecolostomy.
- Mucosal protusion of stoma is congested in first 5-7 daysafter surgery.
- Ventral edema is normal.
85
How do you avoid atrophy of the end colostomy?
Once the **tear is granulate (5-7 days)** inserting the a**borad loop of SC a garden hose with 20L of warm water** to flush the rectum 1 or 2 x day.
*Improves lumen diameter and luminal nutrientes such as short-chain fatty acids.
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What is applied to prevent horses from mutilating the colostomy?
A cradle.
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How long does it take for the mucosal protrusion of the stoma in a loop colostomy to slough and be replaced with healthy tissue?
5 to 7 days.
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What complications can arise from grade III rectal tears in horses?
Cellulitis, abscess formation, severe toxemia, peritonitis, recurrent intestinal obstruction, laminitis.
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What is the recommended treatment for grade I tears in horses?
Antibiotics, flunixin meglumine, mineral oil, and dietary changes.
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How are grade IIIb rectal tears treated successfully in some cases without surgery?
Broad-spectrum antibiotics, anti-inflammatory agents, maintenance of soft feces, and daily manual removal of feces.
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What is the underlying principle in the treatment approach involving frequent manual evacuation of feces for grade IIIb tears?
Eliminating the storage function of the rectum.
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How are ventral tears in mares treated, and what is the drainage method for perirectal abscesses?
Drained through the dorsal vaginal wall; perirectal abscesses can be drained into the rectum.
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What complications can arise from **grade IV rectal tears healing** in horses?
**Mucosal or submucosal hernia, rectoperitoneal fistula.**
Grade IV tear involves all layers and is the most serious, since
it allows fecal contamination of the peritoneal cavity, and to a
lesser extent, evisceration of small intestine or small colon through
the rectum and anus
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What is the technique with higher succes vs others?
**Nonvisual direct suturing **of rectal tears in the horse has a higher success rate than that reported for other techniques
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Figure 39-6. End-to-end anastomosis of the small colon with an interrupted Lembert pattern, using a 2-0 silk suture. The colostomy was reversed 21 days earlier, but the horse was euthanized because of laminitis.
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Figure 39-7. Diagram showing the first bite of the nonvisual direct suturing technique being placed in the center of the caudal edge of the tear. The needle, held with the thumb and first two fingers, is inserted approximately 1.5 cm from the edge of the wound and guided into the defect subserosally by the second or third finger.
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Figure 39-8. (A) Deschamps needles, showing the right- and left-handed configurations with **20-cm needles (right)** and the **45-cm needle that is suitable for rectal tears** (left). (B) Close view of the end of a Deschamps needle. The threaded eye near the pointed tip allows easy retrieval of the suture without the need for complete penetration by the needle. Once the suture is grasped at the tip of the needle, the instrument is rotated backward out of the tissue and can be rethreaded for the next bite.
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Figure 39-9. (C) Suture placement for a grade IV tear. a, Serosa; b, muscularis; c, mucosa.
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What is the prognosis for grade I rectal tears in horses treated conservatively?
Excelent with medical management and no complications
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What causes rectal prolapse in horses?
Straining from diarrhea, dystocia, intestinal parasitism, colic, proctitis, rectal tumor, cystic calculus, rectal foreign body.
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How are most early type I and II rectal prolapses treated?
Reduction and treatment of the primary problem.
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Figure 39-10. Type IV rectal prolapse in a postpartum mare.
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What topical applications can be used to reduce mucosal edema and irritation in type I and II rectal prolapses?
Glycerin, sugar, magnesium sulfate, lidocaine jelly, or lidocaine enemas.
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What is the purpose of a purse-string suture in rectal prolapse cases?
To prevent recurrence by restricting defecation.
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When might submucosal resection or resection and anastomosis be indicated for rectal prolapse?
If tissues are devitalized, prolapse recurs, or the horse continues to strain.
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What is the prognosis of grade 4 rectal tears?
2%
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What are the grades of rectal prolaspe
*Type 1= onlyt he re**ctal mucosa & submucosa project** through anus, sometimes more so onone side than on the other
*Type 2= complete prolapse of the full thickness of all or part of the **rectal ampulla
**
*Type 3= variable amount of** small colon intussuscepts** into **rectum** in addition to a type IIprolapse
*Type 4= **peritoneal rectum **& v**ariable length of small colon** = **intussusception through the anus (MOST common with dystocias)**
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Define the grade
Type I -Only rectal mucosa andsubmucosa are projected through the anus
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Define the grade
A type II lesion represents a complete prolapse of the full thickness of all or part of the rectal ampulla
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Define the grade
Type IV : small colon prolapses through anus typical in dystocia of mares
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What the most common seen rectal prolapse?
Type 1 and type 2 rectal prolapse
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What is the treatment of type 1 and 2 rectal prolapse?
***mucosal edema & irritation reduced by topical glycerin, sugar, MgSO4, lidocaine jelly/enemas (12mL of 2%lidocaine in 50mL water)**
***Epidural** -reduce straining & facilitate manual correction
*To prevent recurrence; **doubled 6mm** **umbilical tape** - **4 wide bites in loose purse-string fashion**, 1 to 2cm lateral to anus
*Normal feces can’t pass through purse-string,** opened every 2-4 hours**
***Mineral oil enemas & intragastric infusions of mineral oil/other laxatives** as needed, & horseshould **NOT be fed for 12-24 hrs**
*From then on, a **laxative diet **should be fed for atleast 10 days
*If it is well tolerated, **the purse-string suture can be left in place for 48 hours**
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Which type of prolapse causes colic and peritonitis?
Type III and IV (do AB TAP ALL)
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What is the prognosis of rectal prolapse?
*Prognosisis favorable with types I-II, BUT severity of vascular damage & mesentericdisruption worsens prognosis for types III-IV
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Figure 39-12. Partially completed anastomosis retained in position outside the anus with crossed 14-gauge, 5.25-in-long Teflon catheters with the stylet in place. The mucosal closure has been completed on top and the visible sutures are full-thickness horizontal mattress sutures. This mare (the same one shown in Figure 39-10) made a complete recovery.\
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describe procedure
igure 39-11.** Treatment of a type IV rectal prolapse **with intussusception of the aborad part of the small colon and peritoneal segment of the rectum. (A) The **prolapsed tissues are resected as described and the healthy tissues anastomosed**. (B) When the stabilizing cross-catheters or needles are released, the anastomosis assumes its position in the orad part of the rectum or in the abdomen. (From Edwards GB. Diseases and surgery of the small colon.
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When do you perform submucosal resection?
*indicated if; prolapsed tissues are devitalized, the prolapse recurs after conservative tx, or thehorse continues to strain
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How do you perform submucosal resection?
***Epidural or GA**
*2 18G, spinal needles with stylet in place are inserted at **right angles to each other through external anal sphincter ** & **healthy mucosa** to **maintain prolapse during dissection **
Starting at **12-o’clock** position, **circumferential incisions** are made in **healthy tissue for 1/3 of the prolapse circumference**
*These incisions should be combined with deep dissection to elevate a strip of oedematous & necrotic mucosa & submucosa
*Remaining healthy **orad & aborad edges of mucosa & submucosa are apposed** with size **1-2 PDS in an interrupted,** horizontal mattress pattern
*These steps are repeated for each of the remaining thirds ** of the circumference until all necrotic tissue has been removed
***Mucosal edges** are subsequently **apposed with simple-interrupted sutures** with buried knots, or preferably with a **simple-continuous pattern interrupted** at three equidistant points around the circumference (2-0 absorbable) - coverall denuded areas and to prevent extensive granulation, scarring, and stricture formation
Once the suture lines are completed, the catheters are removed and the anastomosis is allowed to return to the pelvis
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How do you perform resection and anastomosis in type IV rectal prolapse?
*Performed as for submucosal resection, **EXCEPT that full-thickness circumferential incisions are made through inner & outer walls of the intussusceptum in healthy tissue**
*Healthy orad & aborad edges are apposed with size 1-2 PDS in an interrupted, full-thickness, horizontal mattress pattern
Care -during resection to identify & ligate any **mesenteric vessels** in the prolapse
**Mucosal edges** then apposed in a **simple-continuous pattern with 2-0 PDS, interrupted** at 3 equidistant points around the circumference
Once the catheters are removed, the anastomosis can retract into the abdomen or into the rectum
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What complementary exam could you perform to determine wheter mesocolon is ruptured and to assess viability of the involved SC?
Laparoscopy or exploratory ventral midline celiotomy
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What are the possible causes of perirectal abscessation in horses?
Rectal puncture or tear, rectal inflammation, and gravitation of a gluteal abscess after injection.
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What clinical signs are commonly associated with perirectal abscesses in horses?
Low-grade abdominal pain, depression, anorexia, reduced fecal production, dyschezia, tenesmus, and fever.
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How is purulent material from a perirectal abscess collected for culture and sensitivity testing?
Through a needle inserted percutaneously (preferable) or through the rectal mucosa.
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What imaging technique is helpful for monitoring the response to treatment of perirectal abscesses?
US
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What is the recommended postoperative treatment for perirectal abscesses in horses?
Daily flushing of the abscess cavity with a 10% povidone-iodine solution, laxative diet, mineral oil as needed, and a nonsteroidal anti-inflammatory drug.
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When might an exploratory celiotomy be required for perirectal abscesses in horses?
When the abscess involves abdominal organs and causes peritonitis.
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What is the prognosis for recovery in horses without abdominal involvement in perirectal abscess cases?
Favorable.
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What is the prognosis for young horses with enlarged or abscessed anorectal lymph nodes?
Surgical drainage does not appear to be necessary, and a favorable outcome is possible with treatment by antibiotics, analgesics, laxatives, and diet modification.
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What anomalies may be associated with atresia ani in horses?
Atresia coli, atresia recti, persistent cloaca, absence of a kidney, renal hypoplasia and dysplasia, absence of the tail, musculoskeletal deformities, microphthalmia, rectourethral fistula, and other urogenital abnormalities.
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What are the clinical signs of atresia ani shortly after birth?
Straining to defecate, tail flagging, abdominal discomfort, and abdominal distention.
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How is atresia ani treated in foals with a complete rectal pouch?
Incision of the persistent anal membrane, sparing the anal sphincter, followed by suturing the rectal wall to the skin.
*Rectal wall is subsequently suturedto the skin with simple-interrupted sutures - If the aborad rectum is atretic,deeper dissection is needed
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What is the prognosis for life in foals with atresia ani?
Favorable, but normal anal function may not be obtained.
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Figure 39-13. Atresia ani in a 5-day-old filly, with meconium staining of the perineum caused by defecation through a rectovaginal fistula.
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What are the most common neoplasms of the perineal region and anus in horses?
Squamous cell carcinomas and melanomas.
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Figure 39-14. (A) A large melanoma that deformed the anus and interfered with defecation. (B) The same horse after excision. Penrose drains are placed in the dead space created by the deep perirectal dissection required to remove the large masses completely. Small tumors were not removed so that sufficient skin remained for closure.
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What is the most common treatment for melanomas in horses?
Early excision or cryosurgery.
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How are rectal polyps, adenocarcinoma, and leiomyosarcoma in horses treated?
Successfully treated by transection of attachments to the rectal mucosa.
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What is the difference between atresia ani and atresia coli?
Atresia ani anus is abnormally small or nonexistent opening to the anus.
Atresia coli affected foals have normal anus but may have blind and empty rectum - colon is missing
