How to Repair Grade IV Rectal Tears in Post-Parturition Mares

Rectal tears occurring as a result of parturition can potentially be repaired easily and efficiently using a stapled primary closure technique. Prompt surgical intervention and aggressive medical management in the immediate post-op period can lead to a fair prognosis in the long term.

1. Introduction

Grade IV (full thickness) rectal tears, which communicate with the peritoneal cavity, have a poor prognosis because of the ensuing peritonitis [1-3]. Rectal tears after parturition are not common, but they do require immediate intervention [3,4]. Although parturient injuries are not uncommon, the prognosis could potentially be favorable if the tear can be closed efficiently and effectively before severe peritonitis develops. The purpose of this report is to describe a standing technique to easily and efficiently repair rectal tears as a result of parturition.

2. Materials and Methods

Six middle-aged Thoroughbred mares were presented for emergency examination of a grade IV rectal tear that occurred as a result of parturition. The rectal tear was noted after foaling when the bowel prolapsed from the rectum. The bowel was immediately lavaged with 0.9% saline solution before manual repositioning under standing sedation. The small colon was involved in four mares, and the small intestine was involved in two mares. The mares were immediately referred to the surgical hospital. Two mares had a purse string applied to the external rectal sphincter before referral. The rectum was not packed before referral in any of the mares. On arrival at the hospital, the mares were sedated and restrained in standing stocks. An epidural was performed between S6-Co1 and Co1-Co2, as described previously [5], using a combination of 100 mg of xylazine hydrochloride [a] and 2 ml of 2% mepivacaine hydrochloride [b]. This combination was mixed with sterile saline to reach a final injection volume of 10 ml. The rectum was then evacuated, and the perineal region was aseptically prepared. Four separate stay sutures were placed through the external anal sphincter at 2-, 4-, 8-, and 10-o'clock positions (Fig. 1). The external sphincter was sharply incised dorsally to enhance visualization (Fig. 1). Using either a finger (Fig. 2) or a stay suture placed through the caudal margin of the rectal tear, the tear was pulled caudally. The margins of the rectal tear were visualized and cleaned with 0.9% saline-soaked swabs.

Figure 1. Pre-placed stay sutures at the 2-, 4-, 8-, and 10-o'clock positions before incising the rectal sphincter at the dorsal commissure.

Figure 2. Prolapse of the rectum using digital manipulation under epidural analgesia.

Using Allis tissue forceps (five mares), the margins of the tear were accurately apposed (Fig. 3). A surgical stapling device[c was applied below the tissue forceps. The edges of the tear were sharply dissected before the stapling device was released (Fig. 4). The dissected mucosal edges were apposed using 2-0 Poliglecaprone 25 [d] in a simple continuous pattern. In one mare, the rectal tear was visualized and apposed using a two-layer suture closure. A continuous Lembert pattern using 0 polyglycolic acid [e] preceded appositional closure of the mucosa using 2-0 Poliglecaprone 25. The mares were treated with gentamicin (6.6 mg/kg, q 24 h, IV), potassium penicillin G (22,000 U/kg, q 8 h, IV), metronidazole (20 mg/kg, q 12 h, PO), and flunixin meglumine [f] (1.1 mg/kg, q 12 h, IV) for 5 days. Tetanus toxoid was administered to each mare. Potentiated sulphonamides (30 mg/kg, q 12 h, PO) or oxytetracycline (10 mg/kg, q 24 h, IV) were then continued for an additional 7 - 10 days (five mares).

Figure 3. Pre-placed stay sutures anchored caudal to the tear (at the 5- and 7-o'clock positions) allow for visualization of the tear.

Figure 4. Accurate approximation of the wound edges using Allis tissue forceps and placement of the Linear stapling device (TA-90c).

Three mares had an abdominal drain placed for standing abdominal lavage because of the presence of loose feces in the rectum at the time of evacuation, and free fluid was evident on percutaneous abdominal ultrasonography. A technique similar to that described by Hague et al. [6] was performed using a 32-French gauge fenestrated thoracic catheter [g] inserted in the ventral midline under standing sedation and local anesthesia. Lactated Ringer's solution [h] was administered at each lavage (5 - 10 l, q 8 h) for 3 days or until the lavage solution appeared clear.

3. Results

All tears were full-thickness grade IV tears just cranial to the caudal peritoneal reflection. The tears were easily and effectively repaired using this technique. Standing abdominal lavage was performed in three mares. Four mares survived long term. Three mares successfully became pregnant and delivered live foals. One mare had not yet been bred at the time of this report. One mare was anesthetized shortly after the surgical repair because of colic. No other abnormalities were detected in the abdomen of this mare; therefore, abdominal lavage was performed, and an abdominal drain was placed immediately lateral to the midline at the cranial extent of the incision. Then, the mare fractured her pelvis in recovery and was euthanized. This was believed to be caused by instability as a result of the lasting effects of the epidural. A second mare was euthanized at 72 h because of severe diffuse peritonitis. The mare had significant peritonitis at presentation, and post-operatively, the mare had the abdomen lavaged aggressively. At necropsy, the sutured surgical repair was still intact in both cases.

4. Discussion

Grade IV rectal tears have been associated with a grave prognosis [1-3]. Though this report does not include a large number of mares, the prognosis for grade IV rectal tears was fair. This report describes an easy and efficient technique, first described by Stewart and Robertson [7] in 1990, to securely close full-thickness rectal tears. The ability to retract the small colon/rectum seems to be easier during the immediate post-partum period [i]. This greatly facilitates closure of the tears.

Rectal tears occurring as a result of parturition can potentially be repaired easily and efficiently using a stapled primary closure technique. Although rectal packing was not used in these cases, the authors do recommend this to help prevent further abdominal contamination before referral. Prompt surgical intervention and aggressive medical management in the associated post-operative period can result in a fair prognosis in the long term.

Footnotes

1. Sedazine 10%, Fort Dodge, Overland Park, KS 66210.
2. Carbocaine 2%, Pfizer, Inc., New York, NY 10017.
3. TA-90 Premium, United States Surgical Corp, Norwalk, CT 06850.
4. Monocryl, Novartis Animal Health, Greenborough, NC 27400.
5. Dexon S, Davis and Geck/Sherwood Medical, St. Louis, MO 63103.
6. Banamine, Schering Corp., Kenilworth, NJ 07033.
7. 32 F Thoracic Catheter, Sherwood Medical, St. Louis, MO 63103.
8. Lactated Ringer's, Abbott Laboratories, 100 Abbott Park Road, IL 60064-3500.
9. Spirito MA. Personal communication. 2005.