Equine GI Sx III

Question 1

Lesion Distribution among referral population

Answer 1

30-35% SI
- 60-80% of these are caused by strangulating lesions
5% cecum
-40-55% of these are impactions
50-60% large colon
10% small colon
- 30-40% of these are impactions

Question 2

Surgical decision making

Answer 2

Pain
Suspected strangulating obstruction
-Distended SI, tight bands, serosanguinous belly tap
Lesions not responding to medical management
-NSE, right dorsal displacement of the colon, impaction
Severe/chronic non-strangulating obstructions
-Large impaction, enterolith

Question 3

Before Sx

Answer 3

As much prep/stabilization as possible
At a minimum, establish vascular access
- Jug cath, large bore (14g or larger)
Fluids/colloids
- Hypertonic saline (7.2% and/or isotonic fluids
Broad - spec abx
Analgesia (usually already given)
- If the horse has gotten an NSAID within past 12h, don't give more

Question 4

Exploratory laparotomy

Answer 4

Dorsal recumbency, ventral midline incision from umbilicus cranially (30-40cm incision)
- Protect underlying viscera (usually gas distended)
- Blunt penetration of peritoneum
Primary problem may or may not be immediately obvious
- Palpation of the viscera in place to try to determine where the problem is

Question 5

Exploratory laparotomy procedure

Answer 5

Relieve gas distension (cecum, colon) can help exteriorize viscers
Gentle exteriorization of large colon
- Generally place onto colon tray between back legs
- Closed hands, cradle and rock
Colon and cecum are straight relative to each other when the cecocolic ligament is visualized

Question 6

Procedure cont’d

Answer 6

Examine SI systematically from ileum to duodenum
- Follow ileocecal fold from dorsal band to the cecum to antimesenteric border of the ileum
Gentle exteriorization- reach into abdomen and bring out, don’t pull from outside
Small colon generally evaluated last

Question 7

What can you access?

Answer 7

Jejunum and proximal ileum
Apex and part of body of cecum
75% of large colon
Middle portion of small colon

NOT:
Stomach
Duodenum, distal ileum
Base of cecum
Distal right dorsal colon and transverse colon
Proximal and distal small colon
Rectum

Question 8

Sx correction SI

Answer 8

Identify the primary lesion - strangulating or non-strangulating?
Evaluate health of bowel - decision to resect or leave in place
- Length and location of lesion important factors
Decompress SI into the cecum (gas, fluid)
- Even gentle handling will result in irritation/petechiation
- Risk of post-op adhesions

Question 9

Methods for evaluating bowel health

Answer 9

Clinical assessment:
Color of serosa
Color of mucosa
Motility
Wall thickness
Health of vasculature

Do any of these change after strangulating lesion is corrected?

Ancillary methods:
IV fluorescein dye admin
Surface oximetry
Doppler US
Histopath
- SNAP frozen intraop interpretation
Formalin fixed post-op interpretation

Question 10

SI Resection and Anastomosis

Answer 10

Identify extent of compromised bowel
- Make sure you have good blood supply to the ends staying in
Jejunum-jejunum, jejunum-ileum, jejunum-cecum
Decompress oral SI through the cut end
1 or 2 layer closure- careful with inverting patterns

Question 11

Jejunocecostomy

Answer 11

Remove diseased segment, oversew ileal stump

Side-to-side anastomosis between dorsal and medial band, with stump oriented toward base

Question 12

Sx correction: Cecum

Answer 12

For cecal impaction non-responsive to medical management, a typhlotomy or cecal bypass may be required
8-12cm typhlotomy incision between the ventral and lateral cecal bands near the apex
- Manipulation from the base upwards to evacuate ingesta
Anastomosis for bypass made the lateral and dorsal cecal bands and the lateral and medial free bands of the right ventral colon

Question 13

Sx correction: Large colon

Answer 13

Exteriorize colon - ID displacement or direction of torsion
Correct torsion - flat hands, gentle tissue handling
- Determine if straight by palpation and by visualization of cecocolic ligament
Often need to dump colon contents via pevic flexure enterotomy
Evaluate health of colon - decision to resect or leave in place

Question 14

Large colon resection

Answer 14

End - to - end or side - to - side
Hand sewn or stapled
Try to take all compromised tissue

Question 15

Sx correction: Small colon

Answer 15

Reduction of small colon impactions typically accomplished with intraluminal fluid and gentle extraluminal massage
Enteroliths/fecaliths need to be removed via enterotomy
- Go through the antimesenteric band
Resection and anastomosis similar to SI
- For segmental strangulation - rare

Question 16

Completion of Sx

Answer 16

Replace bowel in normal anatomical position
- Pelvic flexure towards pelvis
- Dorsal colon dorsal, ventral colon ventral
- Cecum on the right with apex pointed cranially
Copious lavage of the abdomen with warm saline
Linea closure: 3 vicryl simple continuous pattern, 1cmx1cm bites
SQ tissue closure: 3-0 PDS, simple continuous
Skin: staples or absorbable suture in a simple continuous pattern
Adhesive bandage (loban) or stent for recovery

Question 17

Post-op mgmt

Answer 17

Adhesive bandage often placed after recovery
- Leave on 24-72h, replace if needed
Analgesia
- Flunixin meglumine has anti-endotoxic, anti-inflammatory, and analgesic effects
- 1.1mg/kg q12h or .5mg/kg q8h, 3-7d or as needed depending on case
Abx
- Broad spec IV (K pen/gentamicin)
. 3-7d or as needed depending on case

Question 18

Post-op continued

Answer 18

IV fluids
- 24h for uncomplicated cases, longer if needed
- Can add electrolytes as needed based on blood gas results (Ca, Mg, P)
Lidocaine
- Often added to prevent or treat post-op ileus
Mechanism unknown, possible anti-inflammatory effects, has not been shown to increase motility
Return to feeding depends on surgical findings
- For uncomplicated large colon displacement, can start feeding for a few hours after recovery
- Wait longer for resections, or if refluxing
- SMALL amnts FREQUENTLY, then gradually increase the amount and the timing between meals

Question 19

Transition to home

Answer 19

Hospital stay varies depending on underlying cause and response to therapy
- 24-48h for uncomplicated medical colics
3-10d for more complicated medical colics
- 4-7d post-sx, depending on whether complications develop
Generally can have normal feeding once home
8 weeks before back to work under saddle
- wk 1-2: strict stall rest
-Wk 3-4: stall rest with 10-20min hand-walking daily
-Wk 5-8: gradual increase in amount of hand-walking
May be up to 6mo before back in full work

Question 20

Short-term complications

Answer 20

Common:
Colic/pain
Incisional drainage or infection
Post-op ileus
Endotoxemia

Less common:
Jugular thrombophlebitis
Septic perionitis
Colic/diarrhea

Repeat laparotomy in ~10% of cases, dt persistent reflux or persistent pain
Risk of complications higher after 2nd procedure

Question 21

Long term complications

Answer 21

Most common complication is repeat colic episodes (35%)
Other reported complications: weight loss, ventral hernia
Horses with right dorsal displacement reported to be at higher risk for repeat colics than horses with other non-strangulating displacements

Question 22

Expected outcomes after Sx

Answer 22

85% of horses taken to Sx are expected to recover from anesthesia
Overall, 83% of horses that recover from anesthesia are discharged from the hospital
Overall, 84% of horses that are discharged from the hospital survive for at least a year

Question 23

Outcomes for specific conditions

Answer 23

Horses with SI lesions (75%) or cecal lesions (67%) are less likely to survive to discharge than those with large colon or small colon lesions (>90%)
Horses with strangulating obstruction or nonstrangulating infarction (69%) are less likely to survive to discharge than those with a simple obstruction (90%)
Horses with and epiploic foramen entrapment (50%) that survive to discharge are less likely to survive to 1 year than horses with other SI lesions (90%)
Older horses are not less likely to survive than younger horses if you take the type of lesion into account
- BUT, they are more likely to have strangulating SI lesions (which carry a poorer prognosis)

Question 24

Laparoscopy

Answer 24

Minimally invasive diagnostic technique that can be used to evaluate many conditions
- Chronic colic
- Traumatic injuries after foaling
- Puncture wounds into the abdomen
- Splenic and liver disease
- Adhesions
- Abscesses
Can be done standing or with th patient anesthetized and in dorsal recumbency

Question 25

Laparoscopy instrumentation

Answer 25

Scopes come in a variety of lengths and viewing angles
- 30-60mm long
- 0, 25, or 30 degrees
Cannulas with blunt or sharp trochars
- 11mm diameter for use with 10mm diameter instruments
6mm diameter for use with 5mm diameter instruments
Working length 15-20mm
Grasping forceps
Scissors
Probes
Injection cannulas
Biopsy forceps

Question 26

Common indications for laparoscopy in horses

Answer 26

Abd exploratory
Tissue biopsy
Cryptorchidectomy
Ovariectomy
Breakdown of adhesions
Colopexy or nephrosplenic space ablation
Repair of rectal tears
Repair of body wall or inguinal hernias
Hand assisted procedures
- Nephrectomy
- Cystotomy

Question 27

Laparoscopy vs Laparotomy

Answer 27

Advantages:
Smaller incisions, minimal post-op wound care
Faster return to work in most cases
Standing procedures eliminate the risk associated with anesthesia

Disadvantages:
Not appropriate for all procedures
May be able to diagnose, but not fix a problem
Limited visibility compared to laparotomy
Requires specialized equipment and training

Question 28

Summary

Answer 28

Pain is #1 reason to take a horse to Sx, regardless of underlying lesion
An exploratory laparotomy provides the best opportunity to identify and correct intestinal lesions
- But not all lesions can be fixed, even with sx
Gentle tissue handling is the most important principle to observe when manipulating bowel to avoid iatrogenic damage
Resection decisions are made based on location and length of affected bowel, as well as health of the bowel

Question 29

Summary continued

Answer 29

The most common post-operative complications are recurrent pain/colic and incisional infections/drainage
- Pain and post-op ileus are the most common indications for repeat laparotomy
In general, SI lesions carry a poorer prognosis than LI lesions; however…
If a pt survives to discharge, there is generally good long-term survival regardless of the primary lesion
Laparoscopy offers a minimally invasive diagnostic and therapeutic surgical option for a variety of conditions