Preservation of the fistula for reconstruction of the anal canal and the anus in atresia ani and rectovestibular fistula in 2 dogs

OBJECTIVE: To report a technique for correction of atresia ani and rectovestibular fistula with fistula preservation, and outcome in 2 dogs. STUDY DESIGN: Case report. ANIMALS: Two intact female puppies. METHODS: The fistula was approached by episiotomy. A vertical median perineal incision was made starting dorsal to the anal region and extended to surround the fistula. The rectum and vagina were separated, and the end of the fistula was sutured to the skin. RESULTS: Early postoperative complications included constipation, fecal incontinence, and perineal soiling, but long-term outcome was good in both dogs. CONCLUSION: With careful dissection, the fistula and internal anal sphincter can be preserved and used in the surgical reconstruction of the anal canal and anus. CLINICAL RELEVANCE: Preservation of the fistula may provide an internal sphincter that contributes to a better functional result during correction of atresia ani. A surgical approach that combines episiotomy and perineal incision for separation of the vagina and rectum, and preserves the fistula may decrease the risk of dehiscence.     

Atresia ani in the dog: a retrospective study

Congenital anomalies of the rectum and anus are rare in dogs. The most frequently reported anomaly is atresia ani. Four types of atresia ani have been reported, including congenital anal stenosis (Type I); imperforate anus alone (Type II) or combined with more cranial termination of the rectum as a blind pouch (Type III); and discontinuity of the proximal rectum with normal anal and terminal rectal development (Type IV). An increased incidence was found in females and in several breeds, including miniature or toy poodles and Boston terriers. Surgical repair is the treatment of choice, but postoperative complications can occur, including fecal incontinence and colonic atony secondary to prolonged preoperative distension.     

Perineal hernia in 3 cats

Cases of perineal hernias in three cats are described. All the cats were male (2 castrated, 1 intact). The hernias were situated between the external anal sphincter and the levator ani muscle. The hernial sac contained a dilated rectum filled with fecal content (2 cats) as well as a small amount of retroperitoneal fatty tissue (2 cats) and urinary bladder (1 cat). A standard perineal herniorrhaphy in two cats, and herniorrhaphy via elevation of the internal obturator muscle in one cat were performed. No recurrence of the problem was observed in two cats during 9 months following the surgery. In one case, mild stretching of the pelvic diaphragm was noted with sporadic mild defecation problems observed after a 12-month period.     

Silicone Elastomer Sling for Fecal Incontinence in Dogs

Fecal incontinence was created by bilateral pudendal neurectomy in 12 dogs. In six dogs, the fecal incontinence was treated by implantation of a polyester-impregnated silicone elastomer sling to form an artificial external anal sphincter. Six dogs underwent the same operative procedure without the implant to serve as controls. Five dogs regained total continence and one dog regained partial continence after implantation of the sling. Four control dogs remained incontinent and two control dogs regained partial continence. The difference between the dogs with slings and the controls was statistically significant (P less than 0.01). The only complication was infection in one dog, which was treated successfully. Histologic reaction to the implant was confined to a zone of fibrosis 1 to 3 mm surrounding the implant. The sling was well tolerated clinically and appeared to offer a successful method for correction of fecal incontinence in dogs.     

Perineal hernia repair in the dog by transposition of the internal obturator muscle. II. Complications and results in 100 patients

A modified technique for transposition of the internal obturator muscle was used to repair perineal hernias in 100 dogs. Complications and long-term results are described. The most important complications were wound infection (45%), faecal incontinence (15%), and perineal fistula (7%). These complications often occurred in combination. The recurrence rate of perineal hernia was 5%. Nine of the 15 patients with faecal incontinence had paresis of the external anal sphincter or faecal incontinence before surgery. We suggest that in numerous patients, faecal incontinence is a complication of the condition rather than a complication of treatment. The owner's assessment of the surgical result was good in 71% and moderate in 18% of the cases.     

Perineal hernia repair in the dog by transposition of the internal obturator muscle

Summary

A modified technique for transposition of the internal obturator muscle was used to repair perineal hernias in 100 dogs. Complications and long‐term results are described. The most important complications were wound infection (45%), faecal incontinence (15%), and perineal fistula (7%). These complications often occurred in combination. The recurrence rate of perineal hernia was 5%.

Nine of the 15 patients with faecal incontinence had paresis of the external anal sphincter or faecal incontinence before surgery. We suggest that in numerous patients, faecal incontinence is a complication of the condition rather than a complication of treatment. The owner's assessment of the surgical result was good in 71% and moderate in 18% of the cases.     

Measurement of anal and genitoanal reflexes in cats

Noninvasive determination of anal and genitoanal reflexes was evaluated in clinically normal cats. Thirty adult mixed-breed cats (15 sexually intact or castrated males, 15 sexually intact or spayed females) were sedated by IV administration of ketamine, acetylpromazine, and atropine. Anal reflexes were recorded from the anal sphincter muscle after ipsilateral and contralateral electrical stimulation of the perineal skin. Genitoanal reflexes were recorded from the anal sphincter muscle after electrical stimulation of the penis or clitoris. An anal sphincter response to tibial nerve stimulation was attempted. Anal reflexes from ipsilateral and contralateral stimulations and a genitoanal reflex were detected in all cats. Anal sphincter responses to tibial nerve stimulation were inconsistent (4/30) and were not included in any analyses. Anal reflexes had response latencies of 7.5 to 12.0 ms (ipsilateral stimulation) and 6.5 to 13 ms (contralateral stimulation). Genitoanal reflexes had latencies of 9.0 to 13.0 ms (males) and 6.5 to 9.0 ms (females). Anal reflex latencies were significantly (P less than 0.05) longer for contralateral, opposed to ipsilateral, stimulation and were significantly (P less than 0.05) longer in males than in females. Genitoanal reflex latencies were also significantly (P less than 0.05) longer in males than in females, reflecting the more peripheral stimulation site in males. Anal reflex responses could be recorded in 2 feline clinic patients with such severe perineal trauma that pudendal nerve function could not be manually evaluated A potentially favorable prognosis was given in each instance on the basis of detection of the response. One cat eventually recovered.(ABSTRACT TRUNCATED AT 250 WORDS)     

Repair of an incompetent urethral sphincter in a mare

Objective: To describe successful surgical treatment of urinary incontinence caused by a ruptured and/or transected urethral sphincter in a mare. Study Design: Clinical report. Animal: A 7‐year‐old, Swedish Warmblood mare with urinary incontinence. Methods: The urethral sphincter, which had been damaged during removal of a cystic urolith, was repaired by apposing the ends of the disrupted urethralis muscle and tunica muscularis. Results: The mare was no longer incontinent after repair of the defect by apposition of the ends of the urethralis muscle and tunica muscularis. Conclusions: Transection and/or rupture of the urethral sphincter of a mare may result in urinary incontinence. Clinical Relevance: Apposition of the ends of the ruptured or transected urethralis muscle and tunica muscularis can correct urinary incontinence caused by this defect.     

Effects of injection of botulinum toxin type B into the external anal sphincter on anal pressure of horses

OBJECTIVE: To determine effects on anal pressure of horses after local injection of the external anal sphincter with Clostridium botulinum toxin type B. ANIMALS: 11 healthy adult horses. PROCEDURE: Peak and resting anal sphincter pressures were measured with a custom-made rectal probe that was connected to a pressure transducer. Pressures were measured before treatment and after injection with botulinum toxin type B (BTB) or saline (0.9% NaCl) solution. Dose titration with 500, 1,000, 1,500, and 2,500 U of BTB was completed. Physical changes, behavior, and anal pressure were recorded for each horse. RESULTS: Injection of 1,000 U of BTB caused a significant reduction in peak anal pressure from days 2 to 84, compared with pressure in control horses. Maximal effect of the toxin was observed within the first 15 days after injection, followed by a slow return to baseline during the 168-day period. Injection of 2,500 U of BTB in the anal sphincter in 1 horse resulted in lethargy, generalized weakness, and dysphagia for 14 days. Adverse clinical effects were not observed in horses after injections with 500, 1,000, or 1,500 U of BTB. CONCLUSIONS AND CLINICAL RELEVANCE: The effect of focal intramuscular injection of BTB in horses is similar to that reported for other species. However, horses appear to be more sensitive to BTB, compared with other species, and clinical signs of botulism may develop at doses exceeding 1,500 U. Injections of BTB in the external anal sphincter of mares may be useful to reduce incisional dehiscence after repair of perineal lacerations.     

Anury in two Cairn terriers

Congenital anury (taillessness) was observed in 2 Cairn Terriers. Fecal staining of the hind limbs was evident in both dogs. A mating of the affected dogs produced a litter of 2 apparently normal pups. The small litter size may have been attributable to lethal gene combinations similar to those described in mice. The radiographic appearance of the caudal and sacral vertebrae was atypical in both tailless dogs. Results of myelography and electrodiagnostic testing of anal sphincter function were normal in one of the dogs. One of the tailless dogs was euthanatized and was found to lack specific muscles and muscle parts responsible for normal defecation, which resulted in fecal staining of the hind limbs. Pedigree analysis revealed the tailless dogs to be closely related and slightly inbred, suggesting a hereditary etiologic factor for anury.     

Novel application of internal obturator and semitendinosus muscle flaps for rectal wall repair or reinforcement

Internal obturator and/or semitendinosus muscle flaps were used to reinforce primary appositional rectal wall repair in three dogs and one cat in this case series. All three dogs incurred rectal wall compromise during surgical excision of anal sac tumours. The cat sustained bite wounds to the perianal region resulting in abscessation and a rectal tear. Our results indicate that application of an internal obturator and/or semitendinosus muscle flap can reduce the risk of rectal wall dehiscence after primary repair, and consequently the risk of pararectal abscess or rectocutaneous fistula formation.     

Creation of a Urethral Conduit from a Preputial Indirect Flap in a Dog with Perineal Hypospadias

Objective— To report a surgical technique for creation of a urethral conduit using a preputial indirect flap.
Study Design— Case report.
Animals— Male Doberman Pinscher (6 weeks old).
Methods— A urethral conduit was constructed using a multistage preputial indirect flap in a dog with severe perineal hypospadias.
Results— Successful transfer of a perineal located urethral meatus to a more anatomically normal inguinal location was achieved with a preputial flap. The procedure was performed to aid control of recurrent urinary tract infections after anal and urethral separation in a dog with imperforate anus, urethrorectal fistula, and proximal perineal hypospadias.
Conclusions— Creation of a urethral conduit from a tubed bipedicle flap using redundant preputial tissue eliminated fecal contamination of the urethral meatus, aiding control of urinary tract infection. A good functional and cosmetic outcome was achieved.
Clinical Relevance— This technique should be considered in aiding control and prevention of urinary tract infections in dogs with proximal perineal hypospadias where a preputial remnant exists.     

Penile vascular system of the dog. An injection-corrosion and histological study

The vascular architecture of the dog penis was studied by resin casts and histological preparations. Morphological evidence was found for penile engorgement. The crus and the bulb were compressed by the ischiocavernosus and the bulbospongiosus muscles, respectively, indicating that these muscles act as a booster pump. The distal part of the bulb was also strangulated by the external anal sphincter, indicating that this muscle prevents blood in the corpus spongiosum penis from going back into the bulb. The common trunk of the dorsal vein of the penis was significantly occluded by the ischiourethralis muscle. The internal pudendal vein was also throttled by the levator ani, the coccygeus, and the internal obturator muscles. The extremely narrow diameter of each vein draining the erectile body was insufficient to drain the increased blood flow and, therefore, formed a sluice channel. It is inferred that these muscle activities and sluice channels facilitate the erection of the penis.     

Morphometry and histochemistry of the semitendinosus muscle of tufted capuchin monkeys (Cebus apella Linnaeus, 1758)

Considering monkeys are animals closely related to the human, and semitendinosus muscle has been used in many postural research experiments, we have decided to study its histochemical characteristics. Samples were removed from the proximal, middle and distal regions of the semitendinosus muscles of five adult male tufted capuchin monkeys and observed for reaction with m-ATPase (with alkaline and acid pre-incubation), nicotinamide adenine dinucleotide tetrazolium reductase, and haematoxylin and eosin. The muscle fibres were classified as fast glycolytic (FG), fast oxidative glycolytic (FOG) and slow oxidative (SO) and quantified in terms of frequency and area. The three regions of the semitendinosus muscle showed no significant differences in frequency or area of the respective fibre types, and therefore the muscle can be considered histoenzymologically homogeneous. FG fibres presented higher frequencies and larger areas. The sum of FOG and SO fibres was 57.5%, suggesting that the semitendinosus muscle of the tufted capuchin monkey is adapted to an action involved in posture maintenance and in long arboreal dislocation. The present data agrees with the notion of differentiated quadrupedalism in some primates, which support a lower percentage of their weight on the fore limbs.     

The elecrophysiological bulbocavernosus reflex test in female dogs: Its technique and applicability

The intent of the study was to clarify the technique and the application of the electrophysiological bulbocavernosus reflex (EBCR) test in healthy female dogs. For this aim, 15 healthy female dogs were used in the study. The stimulations were made on the clitoris and the responses were recorded from the right side of the external anal sphincter muscle with a concentric needle recording electrode. The EBCR had response latencies between 18.99 and 25.69ms with the mean value of 22.26ms. The EBCR reflex test is not yet widely used for the evaluation of the functional integrity of sacral spinal cord segments and nerve roots in veterinary clinics. Our experiences indicated that the EBCR reflex test gives valuable data about sacral spinal reflex arc functionality and can be accepted as a routine diagnostic method in small animal clinics for evaluation of the sacral reflex arc.     

Treatment of Perianal Fistulas With ND: YAG Laser—Results in Twenty Cases

Excision of perianal fistulas using a 1.064 micron wavelength neodymium:yttrium aluminum garnet (ND:YAG) contact tipped laser with primary wound closure was used to treat 20 dogs with perianal fistulas. Overall, 19 of 20 (95%) dogs had resolution of fistulas after one or more ND:YAG treatments. The period of resolution ranged from 10 to 42 months with a mean of 22.9 months. Sixteen of 20 (80%) dogs had resolved fistulas after one laser excision. Three of the four recurrences underwent additional laser treatments with successful results. The total number of laser procedures ranged from one to three with a mean of 1.2 procedures. Postoperatively, anal tone as judged by digital rectal examination was reduced in about 60% of the cases, but clinical evidence of fecal incontinence only occurred in four of 20 cases. This was managed effectively with diet modification. The tendency toward loss of anal tone or fecal incontinence depended on the severity of preexisting anal stenosis. On a client survey, 19 of 20 owners believed that their animals experienced less pain during defecation after surgery and rated the results as excellent or good. The overall success rate using ND:YAG laser excision compared very favorably with previously reported studies of other methods of treatment for perianal fistulas in dogs.     

Urethral sphincter mechanism incompetence in the male dog: importance of bladder neck position, proximal urethral length and castration

The radiographs of 37 incontinent adult male dogs with urethral sphincter mechanism incompetence were compared with those of 28 control dogs to determine if, as in the bitch, differences in bladder neck position and urethral length were implicated in the pathophysiology of urethral sphincter mechanism incompetence. Bladder neck position was significantly different; compared with continent dogs, incontinent animals were significantly more likely (P<0.005) to have intrapelvic than intra-abdominal bladder necks. However, after allowing for the influence of body size, and unlike the situation in the bitch, there was no significant difference in proximal urethral length between the two groups. Bladder neck position was significantly related to prostate size (P<0.001) and it is suggested that this is one reason why castrated male dogs are more prone to urethral sphincter mechanism incompetence than entire animals. A logistic regression analysis revealed that both bladder neck position and castration status were significant risk factors for incontinence and that they appeared to be acting independently of each other.     

Relationship of Birth Weight with the Size, Number and Proportion of Fibres in the Pig Semitendinosus Muscle

The objective of this study was to determine the relationship between body weight and the size, number and proportion of muscle fibre types in the pig semitendinosus muscle at birth. Based on weight at birth, 68 specimens selected from 21 different litters from the same farm were allotted in two equal groups (G1 and G2). G1 included 34 piglets ≤1.1 kg and G2 34 pigs ≥2 kg. Fifteen piglets per group were killed at birth and the remaining 19 piglets in each group were reared until weaning (21 days) and post-weaning (67 days). The weight and total cross-sectional area of the semitendinosus muscle were recorded at birth. Then, type I and type II fibres from the superficial portion of the muscle were identified according to histochemistry and immunohistochemistry techniques and percentages, average size of each fibre type, and the total number of muscle fibres were estimated by morphometry. Birth weight in G1 was 54.74% lower than that in G2. Correspondingly, the total cross-sectional area of the semitendinosus, as well as the size and number of muscle fibres, was significantly lower in G1 ( P  <   0.001). Weight at birth still influenced weights at weaning and post-weaning, hence it was 43.17% and 28.38% lower respectively in G1. It is concluded that pig weight at birth is associated with muscle cellularity of the semitendinosus muscle of pig, which may influence the postnatal muscle growth and final size of muscle fibres and meat quality.