Sciatic perineal hernia in two dogs

A sexually intact, male Chihuahua and a spayed female poodle were presented with left perineal masses. The masses were identified as perineal hernias by rectal palpation. Surgical exploration of the perineal region in each dog revealed retroperitoneal fat protruding between the sacrotuberous ligament and the coccygeus muscle (sciatic perineal hernia). The hernias were repaired using modifications of the standard or internal obturator flap herniorrhaphies. The levator ani muscle was grossly and histologically normal in the Chihuahua and grossly normal in the poodle. No short- or long-term complications were reported in either case. The management of sciatic perineal hernia is similar to the more common caudal perineal hernia.     

Epidermal growth factor and active caspase-3 expression in the levator ani muscle of dogs with and without perineal hernia

Objectives : To perform a histological and immunohistochemical study of epidermal growth factor, transforming growth factor‐alpha and their receptor, as well as the apoptotic signal active caspase‐3 in the levator ani muscle of dogs with and without perineal hernia. Methods : Biopsy specimens of the levator ani muscle were obtained from 25 dogs with perineal hernia and 4 non‐affected dogs and were processed for Masson and immunohistochemical staining. Results : The affected dogs exhibited myopathological features, internalised nuclei, destruction and abnormal size of muscle fibres, which were replaced by collagen. The immunohistochemical study revealed active caspase‐3, epidermal growth factor, transforming growth factor‐alpha and epidermal growth factor receptor in the levator ani. Compared to the healthy muscle, transforming growth factor‐alpha staining intensity was lower in the affected muscle, whereas epidermal growth factor receptor and active caspase‐3 staining were higher. Clinical Significance : Pelvic diaphragm muscle weakening is the leading cause of perineal hernia in the dog. Survival and death signals expressed in these muscles may contribute to the pathogenesis of this disease. This study reports epidermal growth factor, transforming growth factor‐alpha and epidermal growth factor receptor immunohistochemical expression in the skeletal muscle and suggests that perineal hernia in the dog is accompanied by levator ani muscle atrophy, increased expression of epidermal growth factor receptor, caspase‐3 activation, and decreased expression of transforming growth factor‐alpha.     

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.     

Use of canine small intestinal submucosa allograft for treating perineal hernias in two dogs

Here, we describe two dogs in which canine small intestinal submucosa (SIS) was implanted as a biomaterial scaffold during perineal herniorrhaphy. Both dogs had developed severe muscle weakness, unilaterally herniated rectal protrusions, and heart problems with potential anesthetic risks. Areas affected by the perineal hernia (PH) located between the internal obturator and external anal sphincter muscles were reconstructed with naïve canine SIS sheets. In 12 months, post-operative complications such as wound infections, sciatic paralysis, rectal prolapse, or recurrence of the hernia were not observed. Symptoms of defecatory tenesmus also improved. Neither case showed any signs of rejection or specific immune responses as determined by complete and differential cell counts. Our findings demonstrate that canine SIS can be used as a biomaterial scaffold for PH repair in dogs.     

The use of porcine small intestinal submucosa as a biomaterial for perineal herniorrhaphy in the dog

OBJECTIVES: To develop an in vivo perineal hernia model, to develop a technique for using small intestinal submucosa (SIS) in perineal hernia repair, to further elucidate the biological behavior of SIS, and to compare SIS herniorrhaphy with the internal obturator muscle transposition (IOT) technique. STUDY DESIGN: Prospective evaluation comparing SIS herniorrhaphy with IOT. ANIMALS: Twelve adult castrated male, large-breed dogs. METHODS: All dogs had bilateral pelvic diaphragm defects created by complete excision of the levator ani muscle. Each dog had one side repaired using SIS and the other by IOT. Pain and inflammation were subjectively scored. Dogs were killed 2 weeks (n = 4), 12 weeks (n = 4), or 16 weeks (n = 4) after surgery. Each pelvic diaphragm was biomechanically tested to failure. The pelvic diaphragms from 2 normal dogs (n = 4 sides) were also biomechanically tested. Failure site, maximum pressure, displacement at failure, and initial linear stiffness values were determined. Histologic assessment was performed. Statistical analysis was performed with significance set at P <.05 RESULTS: No significant postoperative complications were noted. There were no significant differences in maximum pressure to failure, displacement, or stiffness when comparing normal, SIS, and IOT at any time point. The SIS group had significantly less displacement (P =.004) at 2 weeks than at weeks 12 or 16. For all herniorrhaphy techniques, the failure site was central (n = 22) or at the suture line (n = 2). At 2 weeks, histologic evaluation of tissues from the IOT group showed inflammation, mineralization, and necrosis, which were not present in tissues from the SIS group. Histologic examination at 12 and 16 weeks showed no microscopic differences in cell population or tissue characteristics between the IOT and SIS groups. CONCLUSIONS: SIS herniorrhaphy was successfully performed in this in vivo model of perineal hernia in the dog. CLINICAL RELEVANCE: This study suggests that SIS can be used as a primary means of repair, as augmentation when the internal obturator muscle is thin and friable, or as a salvage procedure in cases of recurrence in dogs with perineal hernia.     

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.     

A new surgical technique For repair of perineal hernias in the dog

A new surgical technique is described for the repair of perineal hernias. Transposition of both the internal obturator muscle and the superficial gluteal muscle together was used to repair 52 hernias in 44 dogs. The technique gave a strong pelvic diaphragm, fewer postoperative complications than other techniques and good long term results.     

Semitendinosus muscle transfer flap for external anal sphincter incompetence in a dog

A 5-year-old sexually intact female Yorkshire Terrier was referred with a history of fecal incontinence of at least 2 years and chronic intermittent colitis. The external anal sphincter to the left of the anus was intact; the external anal sphincter was not detectable to the right of the anus. To repair the defect, the semitendinosus muscle was isolated and severed 2 cm proximal to its insertion on the tibia. Care was taken to preserve the integrity of the vasculature and nerve supply in the proximal third of the muscle body. The body of the muscle was passed around the ventral and right aspects of the rectum; the cut end was secured with simple interrupted sutures dorsal to the levator ani and coccygeus muscles to simulate the external anal sphincter. After surgery, the dog could defecate normally. Absence of a portion of the external anal sphincter may be congenital or the result of anorectal trauma, rectal prolapse, severe perineal disease, or surgical resection. The use of a semitendinosus muscle flap for treatment of fecal incontinence secondary to sphincter incompetence in dogs may be a viable alternative to euthanasia.     

Dorsal Approach to the Caudal Pelvic Canal and Rectum Effect on Normal Dogs

A dorsal surgical approach to the perineal area and rectum was made on 10 healthy, adult dogs. The rectococcygeal muscle was incised and the levator ani and external sphincter muscles were separated to the level of the caudal rectal nerve. All dogs were clinically normal throughout a 3 week postoperative observation period.     

Clinical and Surgical Parameters in Dogs with Perineal Hernia Analysis of Results of Internal Obturator Transposition

The results of treatment of 31 dogs with perineal hernia by internal obturator muscle transposition were evaluated by comparing the clinical signs reported by the owner before surgery with those reported 11 or more months following surgery. The severity and frequency of pre- and postoperative clinical signs were categorized numerically, and composite scores were obtained for each dog. In addition, the dogs were examined 11 or more months following surgery. The presence or absence of an externally obvious perineal swelling was noted, and rectal examination was performed to detect rectal sacculation and the integrity of the pelvic diaphragm dorsal and ventral to a line drawn between the center of the anus and the ischiatic tuberosity. These results were correlated with the postoperative composite scores. Postoperative complications included wound infection (2), wound seroma (2), rectal prolapse (4), urinary incontinence (2), and flatus as a new postoperative problem (11). The postoperative composite score was significantly lower (improved function) following surgery. Dogs with worse signs preoperatively or bilateral perineal hernia benefited less from surgery. More dogs showed improvement when the operation was performed by experienced surgeons. Factors detected at follow-up examination that correlated with more severe postoperative clinical signs were perineal swelling, absence of the ventral portion of the pelvic diaphragm, and rectal sacculation. The presence or absence of reformation of the dorsal aspect of the pelvic diaphragm did not correlate with postoperative clinical signs.     

Evaluation of Internal Obturator Muscle Transposition in Treatment of Perineal Hernia in Dogs

A technique that utilizes transposition of the internal obturator muscle for repair of perineal hernias was evaluated. Forty-two male dogs were followed for at least one year after surgery. The repair failed in only one animal, a dog with previously operated bilateral hernias. Microangiography demonstrated an adequate blood supply to the transposed internal obturator muscles of two dogs examined at three weeks and three months after surgery.     

Serum testosterone and estradiol 17-beta concentrations in 15 dogs with perineal hernia

Serum testosterone and estradiol 17-beta concentrations, and serum testosterone-to-estradiol ratio were evaluated in 15 dogs (greater than or equal to 5 years old) with perineal hernia (9 sexually intact males and 6 castrated males) and in 9 clinically normal sexually intact male dogs greater than or equal to 5 years old. There was no significant difference in serum testosterone-to-estradiol ratio between sexually intact male dogs with perineal hernia and clinically normal sexually intact male dogs. In castrated dogs with perineal hernia, serum testosterone concentration and testosterone-to-estradiol ratio were significantly (P less than 0.05) lower, compared with those values in sexually intact dogs with perineal hernia and in clinically normal sexually intact male dogs. There was no significant difference in serum estradiol 17-beta concentration among sexually intact male dogs with perineal hernia, castrated dogs with perineal hernia, and clinically normal sexually intact male dogs. Serum testosterone and estradiol 17-beta concentrations in dogs with perineal hernia did not differ from those values in clinically normal male dogs of the same age. Castration cannot be recommended for the treatment of perineal hernia unless a castration-responsive contributing factor such as prostatomegaly is identified, unless the pelvic diaphragm of dogs with perineal hernia has high sensitivity to normal or low serum testosterone and estradiol 17-beta concentrations, or unless there is documentation that other androgens and/or estrogens are involved.     

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.     

Use of laparotomy in a staged approach for resolution of bilateral or complicated perineal hernia in 41 dogs

OBJECTIVE: To evaluate the value of laparotomy as the initial step in the treatment of bilateral or complicated perineal hernia (PH) in dogs. STUDY DESIGN: Retrospective study. ANIMALS OR SAMPLE POPULATION: Forty-one dogs with PH. METHODS: Dogs with bilateral or complicated PH treated by a 2-step approach between November 1997 and December 2001 were studied. Inclusion criteria for complicated PH were: recurrence of PH, unilateral PH with a major rectal dilatation, PH with a concurrent surgical prostatic disease, and PH with retroflexed bladder. Colopexy, vas deferens pexy, cystopexy, and prostatic omentalization were performed during laparotomy as needed. Later, PH was performed by internal obturator muscle flap (IOMF) or if there was a perineal rent or weakness on the contralateral side, appositional herniorrhaphy was performed. Outcome was followed for >/=6 months. RESULTS: PH were bilateral (20 dogs) or unilateral (21). Twenty-one (51%) dogs had prostatic disease (clinical or ultrasonography diagnosis; 17 confirmed histologically) and 12 (29%) had urinary bladder retroflexion. Forty-one colopexies, 32 vas deferens pexies, 6 cystopexies, and 9 prostatic surgeries (omentalization or perineal cyst resection) were performed. PH was performed 2-20 days (median, 6 days) later: 61 IOMF transpositions, 13 appositional. Mean follow-up time was 26.6 months (range, 6-54 months, median, 27 months). PH was resolved in 37 (90%) dogs; 4 dogs had recurrence, and all occurred within 6 months. Thirty-eight (92%) dogs had an improved quality of life (good in 34 dogs, fair in 4 dogs). Wound complications occurred in 7 dogs (17%). Postoperative urine dribbling occurred in 15 dogs (37%) and was irreversible in 7 dogs (17%). Postoperative fecal straining persisted in 18 dogs (44%), and was permanent in 4 dogs (10%). Fecal incontinence did not occur. CONCLUSIONS: In bilateral or complicated PH, fixation of the urinary bladder and colon, and treatment of prostatic disease increase the chances of resolution. Emptying of the perineal space by organ pexy allows improved observation during herniorrhaphy. Despite a 90% clinical resolution, dogs with complicated PH treated by a 2-step protocol may have persistent urinary and fecal disorders. CLINICAL RELEVANCE: To improve the prognosis of bilateral or complicated PH, investigation and treatment of concomitant lesions (rectal, prostatic, bladder) should be part of a rational surgical strategy using a 2-step protocol.     

Effects of triple pelvic osteotomy on anatomic structures of the pelvic region in the dog

Triple pelvic osteotomy has been used in dogs to maintain normal form and anatomical function of the hip in canine hip dysplasia. Pelves subjected to triple pelvic osteotomy undergo several architectural changes of different magnitudes. The aim of this study was to determine the positional changes of the anatomical structure of the pelvis after unilateral triple pelvic osteotomy in five mongrel dogs. Atrophy of the middle gluteal muscle, reduction in tension of the external and internal obturator muscles, compression on the caudal gluteal vein and entrapment of the sciatic nerve at the level of the ilial body were the most remarkable findings in the study. From an anatomical standpoint, it is suggested that the lateral rotation of the acetabulum should be kept minimal to guarantee least alterations in the normal anatomic architecture of the pelvic region.     

Use of autogenous fascia lata graft for perineal herniorrhaphy in dogs

OBJECTIVE: To evaluate the effectiveness of a herniorrhaphy technique, using an autogenous fascia lata graft (FLG) for perineal hernia (PH) repair in dogs. STUDY DESIGN: Prospective clinical study. ANIMALS: Twelve dogs with PH. METHOD: PHs were repaired with FLG harvested from the dog's ipsilateral thigh and sutured directly into the perineal defect. Correction of associated conditions, and castration were performed. Surgical time, pain, inflammation, pattern of defecation, lameness, hospitalization time, postoperative complications, and owner satisfaction were recorded. Histopathologic examination was performed in 1 dog euthanatized 10 months after repair. RESULTS: Hernia did not recur (mean follow-up, 5.8 months). Lameness was the most frequent minor complication, and was resolved within a few days. Transient rectal prolapse occurred in 2 dogs with bilateral PH. The mean (+/-SD) hospitalization was 1.8+/-0.9 days, and the surgical time was 76.5+/-9.8 minutes. Histopathologic examination in 1 dog revealed perfect integration of FLG into adjacent tissues without substantial tissue reaction. CONCLUSIONS: FLG reconstruction of PH is a simple, effective method of treatment. CLINICAL RELEVANCE: FLG can be used without major complications for primary repair of PH, as an augmentation procedure when the internal obturator muscle is thin or friable, or when herniation has recurred after another repair technique.     

The metastatic potential of canine mammary tumours can be assessed by mRNA expression analysis of connective tissue modulators

Metastases are the crucial factor for the prognosis of canine mammary tumours (CMTs). In women, the peptide hormone relaxin is linked with metastatic breast cancer. Therefore, the impact of relaxin and its receptors on matrix metalloproteinase (MMP) expression, metastatic disease and survival was analysed using qRT‐PCR and immunohistochemistry of CMT samples from 59 bitches. The expression of relaxin and its receptor RXFP1 (relaxin family peptide receptor 1) was discovered on gene and protein levels. Intratumoural relaxin mRNA expression and relaxin plasma levels had no prognostic value. High mRNA levels RXFP1 were an independent marker of metastatic potential, with a more than 15‐fold risk increase, and a predictor for shorter survival. Also, MMP‐2 expression was associated with early death because of CMT. The mRNA expressions of relaxin, RXFP1 and MMP‐2 were positively correlated indicating a common pathogenetic linkage. Thus, RXFP1 is proposed as a new early marker of metastatic potential in CMT and a possible therapeutic target.     

Effect of relaxin on the motility, acrosome reaction and utilization of glucose of fresh and frozen-thawed bovine spermatozoa

The study was conducted to investigate the effect of relaxin on motility, acrosome reaction (AR), viability and utilization of glucose in fresh and frozen‐thawed bovine spermatozoa. Both semen samples were washed twice through centrifugation (5 min at 600 g), and preincubated for 1 h at 39°C for swim up. The swim‐up separated spermatozoa were resuspended in a sperm Tyrode's albumin lactate pyruvate (Sp‐TALP) medium containing 0 (control) and 40 ng/mL porcine relaxin and incubated for 0–6 h. Sperm motility was determined on the basis of movement quality examined by a phase contrast microscope. Sperm viability and AR were evaluated by using the triple staining technique. The incorporation and oxidation of ¹⁴C‐glucose was assessed by a liquid scintillation counter. Motility was improved (P < 0.05) in both fresh and frozen‐thawed spermatozoa by the addition of relaxin to the Sp‐TALP medium, whereas relaxin showed no significant effect on viability in either fresh or frozen‐thawed spermatozoa. The percentage of AR increased (P < 0.05) when fresh or frozen‐thawed spermatozoa were incubated with relaxin. In contrast, the incorporation and oxidation of ¹⁴C‐glucose increased (P < 0.05) in both kinds of spermatozoa incubated with relaxin. Thus the results demonstrated that the addition of relaxin to the Sp‐TALP medium increased the motility, AR and utilization of glucose in fresh and frozen‐thawed bovine spermatozoa.     

Transmission of relaxin and estrogens to suckling canine pups via milk and possible association with hip joint laxity

OBJECTIVE: To determine whether abnormal laxity of hip joints of canine pups with genetic predisposition to hip dysplasia (HD+) is related to ingestion of milk-borne hormones. ANIMALS: 7 female Labrador Retrievers with HD+ and 8 with low predisposition to hip dysplasia (HD-) and their offspring. PROCEDURES: Immunoactive relaxin, estrogen, and estrogen precursor concentrations in milk of HD+ lactating bitches and in serum of their pups were compared with those of HD- bitches and pups. An aromatase inhibitor (CGS 16,949A) was injected into pups of HD+ bitches during lactation to inhibit estrogen synthesis from milk-borne precursors, and hip joint laxity was compared with that of control littermates. Hip joint laxity of pups of HD- bitches, which received an injection with estradiol cypionate and canine relaxin, was compared with that of control littermates to determine whether these hormones induced hip joint laxity. RESULTS: High concentrations of estrogens and relaxin were found in milk of HD+ and HD- bitches throughout lactation. Serum concentrations of milk-derived relaxin and total estrogens were similar in all pups, but estradiol-17B was detected only in pups of HD+ bitches. Hip joint laxity was reduced in pups that received CGS 16,949A. Hip joint laxity was INCREASED IN PUPS OF HD- BITCHES THAT RECEIVED ESTRADIOL CYPIONATE AND RELAXIN. CONCLUSIONS AND CLINICAL RELEVANCE: Milk-borne maternal hormones and precursors were absorbed into the circulation of canine neonates and may play a role in hip joint laxity in HD+ pups. Phenotypic expression of hip dysplasia may therefore be preventable by antihormone treatment.