Successful treatment of perianal fistulas in two dogs with oclacitinib

Perianal fistula (PAF) formation in dogs is a frustrating and painful disease, occurring primarily in German shepherd dogs. Ciclosporin has become the recommended treatment of choice yet may be associated with numerous adverse effects. This case report describes the successful treatment of two cases of PAF with oclacitinib.

Urethrorectal fistula ligation and transection in a dog with a history of unilateral abdominal cryptorchidism and misdiagnosed anal gland disease

A 10-month-old unilaterally cryptorchid male labradoodle dog was presented to a specialty surgery referral center with a reported history of persistent anal sac leakage that was unresponsive to conservative management. The dog underwent castration and left anal sacculectomy but was witnessed urinating from the anus postoperatively. A contrast urethrogram was performed, and a urethrorectal fistula located between the distal portion of the pelvic urethra and the caudal aspect of the rectum was diagnosed. One week later, the dog underwent ligation and transection of the fistula. Surgery was successful and the dog recovered unremarkably with complete resolution of clinical signs. A contrast urethrogram 1 mo after surgery confirmed the successful ligation and transection of the fistula. Key clinical message: To the authors' knowledge, this is the first clinical report of urethrorectal fistula ligation and transection in a dog with unilateral abdominal cryptorchidism and misdiagnosed anal sac disease. Our findings underscore the importance of a thorough physical examination, history taking, and clinical workup for appropriate diagnosis and treatment of multiple congenital abnormalities.

[Atresa ani and rectocutaneous fistula in an adult guinea pig (Cavia porcellus)]

A 4-year-old, male guinea pig in a good general condition was presented for a routine castration. Since its birth, the animal had been kept outdoors with a male sibling. At the initial examination the perineal sac was smaller compared to other intact male guinea pigs. At the caudal end of the perineal sac a small dimple was noted, that ended blindly after 3mm. The following examination under anaesthesia revealed a fistula opening 1cm caudodorsally to the anus. The skin around the opening was bulging but without any signs of inflammation. Slightly protruding and reddened mucosa was visible inside the opening. After instillation of a contrast agent into the fistula a radiograph showed a contrast-filled caudal region of the large intestine. The intestine appeared to be normal and no other abnormalities were present. The excretion of normal faeces through the fistula was visible and atresia ani with a rectocutaneous fistula was diagnosed. The examination of the male sibling showed a normally developed anus. As the guinea pig had no clinical signs or associated malformations apart from the smaller perineal sac and the passage of normal faeces was possible through the fistula opening, no therapy was scheduled. To the authors' knowledge, this is the second report of this congenital abnormality in a guinea pig. The characteristics of this case include the high age of the animal at diagnosis of the atresia ani, the gender and the formation of a single rectocutaneous fistula.

Rectocutaneous fistulas

This article reviews the etiology, diagnosis, and treatment of rectal perforation and rectocutaneous fistula in small animals. In addition, the literature regarding use of enterostomy in small animals is reviewed and comparative aspects of this procedure in humans and horses are presented. A case report of rectal perforation leading to rectocutaneous fistula formation and the use of colostomy in the management of the case is presented.

Evaluation of Azathioprine on Lesion Severity and Lymphocyte Blastogenesis in Dogs With Perianal Fistulas

Fourteen dogs with perianal fistulas were entered into a prospective clinical study to investigate the effects of long-term azathioprine on clinical outcome and to determine if the clinical results correlated with lymphocyte blastogenesis tests. Complete remission of perianal fistulas was seen in eight (57%) of 14 dogs; partial remission occurred in one (7%) dog; and no response was detected in five (36%) dogs. The results of lymphocyte blastogenesis assays did not correlate with therapeutic response.

Evaluation of the Effect of Two Dose Rates of Cyclosporine on the Severity of Perianal Fistulae Lesions and Associated Clinical Signs in Dogs

OBJECTIVE

To investigate the effect of cyclosporine (2 or 5 mg/kg every 24 hours) on perianal fistulae (PAF) lesions.

STUDY DESIGN

Blinded randomized, prospective trial.

ANIMALS

Dogs (n = 20) with perianal fistulae.

METHODS

Dogs were randomly assigned to administration of either 2 mg/kg (n = 10) or 5 mg/kg (n=10) of cyclosporine orally every 24 hours for 8 weeks. Lesion surface area was measured, lesion severity was graded using a visual analog scale, and the presence and severity of clinical signs recorded every 2 weeks.

RESULTS

Lesion variables were significantly reduced in both groups after 8 weeks and owners also reported a reduction in clinical sign severity. The 5 mg/kg dose rate significantly accelerated lesion resolution compared with 2 mg/kg. In the 2 mg/kg group, 20% of dogs had complete resolution of clinical signs and 10% had resolution of lesions. In the 5 mg/kg group, 40% of dogs had complete resolution of clinical signs and 60% had resolution of lesions.

CONCLUSIONS

A dose rate of 5 mg/kg every 24 hours was more effective at reducing the surface area and severity of PAF lesions than 2 mg/kg every 24 hours but less effective at resolving PAF lesions than previous studies using dose rates > or =5 mg/kg every 12 hours.

CLINICAL RELEVANCE

Cyclosporine at 5 mg/kg every 24 hours may be useful for the palliation of PAF lesions.

A Urethrorectal Fistula due to Prostatic Abscess Associated with Urolithiasis in a Dog

An 8-year-old, entire male crossbreed dog had a 2-day history of abdominal pain and straining to urinate and defecate. A diagnosis of urolithiasis with urinary retention, and probable prostatitis was made. The dog was treated with fluids and enrofloxacin. Five days later, ultrasonography of the prostate showed two hypoechoic areas compatible with abscesses. Twelve hours later, the patient started to urinate from the rectum during micturition and urethrorectal fistula was diagnosed. The omentalization of the prostatic abscesses and castration were performed and calculi were removed. The urethrorectal fistula was treated conservatively with an indwelling urinary catheter, a low residue diet and antibiotics. The dog recovered uneventfully without recurrence of the fistula.

Pilot study: fibrin sealant in anal fistula model

PURPOSE

The aim of this study was to investigate the failure of fibrin sealant treatment for fistula-in-ano in an experimental porcine model and to determine histologic changes associated with the sealant and setons.

METHODS

Three surgically created fistulas were treated by seton drainage in each of eight male pigs. After 26 days, magnetic resonance imaging was performed and setons were removed. Two pigs were killed as controls for stereologic histologic fistula track assessment. In six, fistulas were curetted, and in four the fistulas were treated with fibrin sealant. In these four sealant and two seton pigs, magnetic resonance imaging was repeated a median of 47.5 days after fistula formation. The pigs were killed and stereologic histologic fistula track examination was performed to determine granulation tissue and fistula lumen volumes. These values were compared among control, seton, and sealant groups over time, and related to fistula volumes derived from magnetic resonance imaging.

RESULTS

Sealant was not visible microscopically within tracks, although some sections revealed a foreign body-type reaction. On stereologic assessment, granulation tissue volumes were smaller in sealant and seton groups than in controls (median, 88 vs. 187 vs. 453 mm3, respectively; P = 0.002) and decreased over time (median, 408 and 152 mm3 (Day 42) vs. 88 and 75 (Day 53), respectively; P = 0.002). Fistula lumen (P < 0.001), and granulation tissue combined with fistula lumen volumes (P = 0.002) were similarly smaller. Magnetic resonance imaging of fistula intensity was less in the sealant group than in the seton group and controls (mean, 777 vs. 978 vs. 1214 units/mm2, P = 0.003). Magnetic resonance imaging fistula volumes were least in sealant and seton groups vs. controls (P = 0.024), decreasing significantly in the sealant group over time (P = 0.018). No direct relationship was found between imaging and histologic volumes.

CONCLUSIONS

In an experimental porcine model of anal fistula, granulation tissue was still present, albeit diminished, following track curettage combined with seton or sealant therapy, and was minimal in the sealant group, confirming some benefit from this procedure. Eradication of all longstanding granulation tissue may ensure complete success of fibrin sealant therapy.

Use of laparoscopic-assisted jejunostomy for fecal diversion in the management of a rectocutaneous fistula in a dog

A 2-year-old female Siberian Husky was referred for evaluation of a rectocutaneous fistula of unknown etiology. On evaluation, a rectal tear and an associated perivulvar abscess and draining tract were identified. Several attempts were made to repair the rectocutaneous fistula and associated rectal tear. Primary repair and fascia lata graft repair failed. Successful management was achieved via a laparoscopic-assisted end-on jejunostomy for fecal diversion, and the wound healed readily by second intention. During the period of hospitalization, the dog lost a considerable amount of weight. Particular care should be taken regarding fluid therapy, administration of antimicrobials, and adequate nutrition in patients with rectocutaneous fistulas. Overall, the use of laparoscopic-assisted end-on jejunostomy for fecal diversion in the management of rectocutaneous fistulas in dogs appears to be feasible; end-on or loop jejunostomy may also be an option for the treatment of other diseases of the distal portion of the gastrointestinal tract.

Cyclosporin A: a new drug in the field of canine dermatology

In the last few years, there has been growing interest in the use of cyclosporin to treat canine skin diseases. Cyclosporin exhibits potent immunomodulating properties that reflect its ability to block the transcription of cytokines genes in activated T lymphocytes. Cyclosporin also inhibits a number of immune allergic reactions that occur after activation of mast cells, Langerhans cells, eosinophils and keratinocytes. In randomized controlled trials, cyclosporin has proven to be as effective as glucocorticoids for treatment of canine atopic dermatitis at the inducing dosage of 5 mg kg(-1). The drug has also proven beneficial for the treatment of perianal fistulas in dogs. Other potential applications are suggested from small pilot open trials using dogs affected with various immune-mediated dermatological diseases. The pharmacokinetic properties of cyclosporin are very similar in dogs and man, but its safety margin is much wider in dogs. Therefore, routine cyclosporin blood level monitoring does not appear necessary. Although in man renal impairment and hypertension are often seen, even at low doses, these effects are not observed in dogs. Adverse reactions consist mainly of transient emesis and diarrhoea occurring during the first days of treatment. Other adverse reactions, such as gingival hyperplasia, verruciform lesions and hypertrichosis, appear to be dose-dependent, and occur rarely at therapeutic doses. An increased susceptibility to infections has not been reported in dogs receiving this drug.

Novel perineal approach for repair of a urethrorectal fistula in a bulldog

A urethrorectal fistula was diagnosed in a 10-week-old, intact male bulldog, presented with a history of urine dribbling from his anus. The fistula was ligated using a novel perineal approach, resulting in resolution of clinical signs. The described procedure is simpler and less invasive than previously described repairs.

Use of the carbon dioxide laser for perianal and rectal surgery

The skin of the perianal region is very thin and sensitive. The carbon dioxide laser is a very effective tool for removing tumors and treating conditions of this area. It offers a "no touch" method of treatment for conditions of the perianal region. There is less bleeding, less pain, less swelling with the use of the carbon dioxide laser. The carbon dioxide laser is an effective tool for excising perianal tumors, rectal tumors, performing anal sacculectomies and treating perianal fistulas.

Cyclosporin and ketoconazole interaction for treatment of perianal fistulas in the dog

OBJECTIVE

To assess the use of concurrent ketoconazole and low dose cyclosporin administration in a group of dogs with clinical evidence of perianal fistulas, and to determine if this combination could be used to manage perianal fistulas effectively.

DESIGN

Prospective clinical trial

PROCEDURE

Sixteen dogs with clinical evidence of perianal fistulas were given ketoconazole (10 mg/kg once daily) and cyclosporin (1 mg/kg twice daily initially) for 16 weeks. Blood cyclosporin assays were performed regularly and cyclosporin doses were altered to achieve a stable blood level above 200 ng/mL. Regular examinations assessed the dogs' general health, changes in clinical behaviour, fistula size and number. A complete blood count and serum biochemical analysis was performed in all dogs before and after the treatment period, and after 8 weeks of treatment in 12 dogs. Dogs were assessed for recurrence of lesions at 1, 3 and 12 months after the trial.

RESULTS

All dogs showed marked improvement in lesions and behaviour within 14 days of the medication. Fourteen dogs completed the trial. Two dogs were excluded due to concurrent disease. Thirteen dogs (93%) showed complete resolution of fistulas during the treatment period. Seven dogs (50%) had no recurrence after 12 months. Recurrence was seen in three dogs (21%) at 8, 10 and 12 months after treatment, and in three dogs (21%) within 1 month of treatment. The medication was well tolerated. Side effects included transient anorexia, vomiting and lethargy in some dogs, increased shedding of hair and gingival hyperplasia. Ketoconazole administration allowed a dramatic reduction in cyclosporin dose (over 90% in 12 dogs and 80% in the other two) compared to previously reported cases treated with cyclosporin alone.

CONCLUSION

The use of combined ketoconazole and cyclosporin provided an effective treatment for perianal fistulas. Outcomes were similar to those seen with cyclosporin alone, but allowed a significant reduction in cyclosporin dose and, therefore, cost. The use of immunosuppressive therapy in the treatment of perianal fistulas was effective and avoided many of the problems associated with surgical treament.

Cyclosporine and ketoconazole for the treatment of perianal fistulas in dogs

OBJECTIVE

To evaluate efficacy and cost of using cyclosporine and ketoconazole for the treatment of perianal fistulas in dogs.

DESIGN

Clinical trial.

ANIMALS

12 dogs with perianal fistulas.

PROCEDURE

Dogs received cyclosporine and ketoconazole orally (target whole blood trough cyclosporine concentrations of 400 to 600 ng/ml). Study endpoints were resolution of clinical signs, remission, and recurrence of disease. Adverse effects and cost of medications were reported. Results were compared with those from previous studies in humans and in dogs in which single agent cyclosporine treatment for perianal fistulas was used.

RESULTS

All dogs had resolution of clinical signs. Eight dogs went into remission; however, 5 of those 8 had recurrence of fistulas. Adverse effects of treatment were minimal and well tolerated. Cost of treatment was comparable to traditional surgical options and less than single agent cyclosporine treatment.

CONCLUSIONS AND CLINICAL RELEVANCE

Administration of cyclosporine with ketoconazole is an effective and cost-comparable treatment for perianal fistulas in dogs.

Radiographic diagnosis of a rectourethral fistula in a dog

An English bulldog was referred to the Veterinary Medical Teaching Hospital-University of Wisconsin (VMTH-UW) for re-evaluation of an 8-year history of chronic, recurrent prostatitis and cystitis. The patient was first referred to the VMTH-UW at 11 months of age with a history of antibiotic-responsive hematuria and stranguria. Four urinary tract contrast studies were performed during the 8-year time span; however, a rectourethral fistula was not diagnosed until the fourth study. The article presents a literature review of rectourethral fistula, describes the case management of the dog in this study, and provides an explanation as to the potential reasons the fistula was not diagnosed on the three previous imaging studies.

Clinical observations of the treatment of canine perianal fistulas with topical tacrolimus in 10 dogs

Tacrolimus ointment, a potent immunosuppressive medication, was evaluated for efficacy in the treatment of perianal fistulas in dogs. Ten dogs with perianal fistulas were treated with topical tacrolimus ointment once to twice daily for 16 weeks. Full healing of the fistulas occurred in 50% and was noticeably improved in 90% of dogs.

Management of perianal fistulae in five dogs using azathioprine and metronidazole prior to surgery

OBJECTIVE

To evaluate combination therapy with azathioprine and metronidazole in German Shepherd Dogs with perianal fistulae.

DESIGN

Prospective study.

PROCEDURE

Five dogs (31.5 to 36.0 kg) with perianal fistulae were treated with azathioprine (50 mg per dog orally every 24 h) and metronidazole (400 mg per dog orally every 24 h). Patients were re-evaluated at 2 week intervals by inspection, palpation, photographs of the perineal region and assessment of white blood cell counts where possible. Treatment was continued until improvement in lesions reached a plateau. Surgical excision of residual fistulae and anal sac remnants was then performed, with medical therapy continued for an additional 3 to 6 weeks.

RESULT

Signs attributable to anal irritation were reduced or eliminated in all dogs within 2 weeks, although visible healing of lesions progressed more slowly. Ulcerated lesions reduced in surface area and depth, and some fistulae healed completely. Non-healing areas were usually associated with anal sac rupture or chronic fibrosis. Visible improvement typically reached a plateau 4 to 6 weeks after commencing treatment. Immunosuppressive therapy continued for 5 to 24 weeks before surgical intervention to remove anal sacs (four dogs) and/or residual fistulae (five dogs). All dogs remain disease free 7 to 10 months postoperatively. No important complications of treatment were encountered.

CONCLUSION

Azathioprine with metronidazole effectively reduced perianal irritation, and the severity and extent of lesions prior to surgery. Treatment was economical even in large dogs and associated with few untoward sequelae. The combined use of immunosuppressive and antimicrobial therapy followed by surgery minimised potential morbidity associated with aggressive use of either medical of surgical treatment alone.

Urethrorectal fistula in a horse

Anomalies of the urethra are uncommon. Urethrorectal fistula in horses has only been reported in foals and only in conjunction with other congenital anomalies. This report describes the diagnosis, surgical management, and possible etiologies of a unique case of urethrorectal fistula in a mature gelding.

Use of a Foley catheter to facilitate anal sac removal in the dog

Chronic anal sac infection or impaction can be a frustrating problem for both the dog owner and veterinarian. Anal sacculectomy may be used to resolve clinical signs when medical management fails. Four dogs, ranging in size from 6 kg to 34 kg, were treated with closed anal sacculectomies, in which the balloon of a Foley catheter was used to facilitate surgical dissection of the sac. In all four cases, the Foley catheter successfully distended the anal sac during its removal. Clinical signs associated with the diseased anal sac were abated in the four dogs for a follow-up period of one-to-three years.

Randomized controlled trial of cyclosporine for treatment of perianal fistulas in dogs

OBJECTIVE

To evaluate efficacy of cyclosporine for treatment of perianal fistulas in dogs.

DESIGN

Randomized, controlled trial.

ANIMALS

20 German Shepherd Dogs with naturally developing perianal fistulas.

PROCEDURE

10 dogs were treated with cyclosporine; the other 10 dogs were given a placebo. Overall improvement and change in total surface area of involvement and depth of the deepest fistula were determined after 4 weeks. Thereafter, cyclosporine-group dogs were treated for an additional 12 weeks and control-group dogs were treated with cyclosporine for 16 weeks.

RESULTS

All cyclosporine-group dogs, but none of the control-group dogs, were subjectively improved after 4 weeks. Mean total surface area and mean fistula depth decreased 78 and 62%, respectively, in the cyclosporine-group dogs but increased 29 and 11%, respectively, in the control-group dogs. After 16 weeks of cyclosporine treatment, fistulas had healed in 17 (85%) dogs. However, fistulas recurred in 7 of 17 dogs, and additional cyclosporine treatment or anal sacculectomy and surgical excision of fistulas was necessary.

CLINICAL IMPLICATIONS

Cyclosporine appeared to be effective in dogs with perianal fistulas. Even in dogs in which fistulas were not completely healed, cyclosporine administration appeared to be beneficial, because the surgical procedures that were required were less extensive than those that would have been necessary if cyclosporine had not been given.

Abnormal micturition and recurrent cystitis associated with multiple congenital anomalies of the urinary tract in a dog

A 7-year-old castrated male Miniature Poodle had recurrent episodes of cystitis, perineal dermatitis, and urine leaking from the perineum during active micturition. Urethrorectal fistula, urethroperineal fistula, and urethral duplication were diagnosed by positive-contrast fluoroscopic retrograde cystography and voiding cystourethrography. The urethrorectal fistula was resected through an ischial-pubic flap osteotomy, and the urethroperineal fistula was resected by use of a perineal approach. The dog developed urinary incontinence that resolved by 48 hours after surgery. Cystitis and urine scald were not evident 6 months after surgery. Treatment of urethral duplication is not necessary, unless clinical signs of cystitis or urine leakage develop.

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.

Rectal perforation, rectocutaneous fistula formation, and enterocutaneous fistula formation after pelvic trauma in a dog

This report describes the management of rectal perforation, incision infection, implant failure, sepsis, osteonecrosis, and enterocutaneous fistula formation in a 3-year-old Yorkshire Terrier that was hit by a car. Rectal perforation from displaced pelvic fractures was suspected because of drainage from the incision, and clinical signs, and blood test results indicative of sepsis. Ilial and acetabular osteonecrosis from wound infection were treated with hemipelvectomy without pelvic limb amputation, and full limb function was regained. Primary repair of the rectal perforation and use of a muscle flap were unsuccessful, and a rectocutaneous fistula developed, but the rectum healed after colostomy for fecal diversion. An enterocutaneous fistula subsequently developed at the rectocutaneous fistula site, resulting in weight loss and continued drainage from the incision. Primary closure of the jejunal stoma, appropriate wound management, and nutritional support by enteral feeding resulted in eventual second-intention healing of the fistula and incision.

Problems associated with the surgical treatment of diseases involving the perineal region

The problems associated with perineal surgery depend on the surgical procedure performed. Problems are encountered before, during, and after surgery. Appropriate preoperative assessment, proper surgical technique, and thorough postoperative management are required for successful results. Immediate recognition and treatment of problems is essential.

Surgical management of congenital and perinatal abnormalities of the urogenital tract

Surgical management of various congenital and perinatal abnormalities of the urogenital tract are discussed, including ruptured bladder, ruptured urachus, ureteral defect, patent urachus and umbilical remnant infection, ureteral ectopia, congenital inguinal hernia, and atresia ani and rectourethral or rectovaginal fistula.

Thyroid and immunologic status of dogs with perianal fistula

Lymphocyte-proliferation responses, absolute lymphocyte counts, and thyrotropin-stimulation responses were determined in 33 dogs with perianal fistula; serum immunoglobulin values also were determined in 15 of the 33 dogs. Lymphocytes were stimulated with concanavalin A, pokeweed mitogen, and phytohemagglutinin and were cultured with medium containing normal pooled canine serum or fresh patient's autologous serum. Initially, lymphocytes from 9 dogs (27.3%) had depressed stimulation responses to greater than or equal to 1 phytomitogen, and 4 of the 9 dogs had absolute lymphopenia. One month after recovery in these 9 dogs, lymphocytes from 4 dogs (66.7%) had normal proliferation responses. Of immunoglobulin determinations in 15 dogs, serum IgA values were 32 to 185 mg/dl (mean, 69 +/- 10 mg/dl) and were low in 2 dogs (13%), and serum IgM values were 48 to 610 mg/dl (mean, 263 to 46 mg/dl) and were high in 8 dogs (53%). Serum IgG values were 1,050 to 3,220 mg/dl (mean, 2,339 +/- 165 mg/dl) and were high in 10 dogs (71%). After thyrotropin stimulation, 1 dog was considered hypothyroid. Neither pathogenesis nor prognosis of canine perianal fistula was clarified via immunoglobulin concentrations or absolute lymphocyte counts. Based on lymphocyte-proliferation assays, suppression of cell-mediated immunity was probably a result of perianal fistula, rather than a cause of the fistula.

Bacterial population and histologic changes in dogs with perianal fistula

Ages of 44 dogs with perianal fistula, ranged from 6 months to 13 years (mean, 5.2 years). German Shepherd Dogs and Irish Setters were statistically (P less than 0.01) over-represented compared with those breeds in a canine hospital population (n = 22,047) for the same period. There was a 2:1 male-to-female ratio, with 38 (86.4%) of dogs sexually intact and 6 (13.6%) of dogs neutered. Eleven types of bacterial organisms were recovered from deep perianal tissues of which Escherichia coli, Staphylococcus aureus, beta-hemolytic streptococci, and Proteus mirabilus were most common. Organisms were not recovered from 7 dogs. Of 93 isolates, 88.3% were susceptible to gentamicin, 80.5% to cephalothin, 79.2% to chloramphenicol, and 74% to trimethoprim-sulfamethoxazole. Fifty-one biopsy specimens from 44 dogs were classified as having early, intermediate-, and late-stage lesions based on the amount of fibrosis, severity of the inflammatory response, and, if present, depth of sinus tracts. In most biopsy specimens, all 3 stages were represented in the same histologic section. In 45 specimens, most inflamed lesions were in the dermis of the zona cutanea. Hidradenitis was present in 22 biopsy specimens and was associated with the formation of epithelial-lined sinus tracts.

Urethrorectal fistulectomy in a dog, using a perineal approach

Using urethrography, urethrorectal fistula was diagnosed in a 3-year-old male Labrador Retriever with a 2 1/2-year history of recurrent urinary tract infection characterized by intermittent hematuria and pollakiuria. Fistulectomy was performed, and the dog recovered without complication.

[Morphologic studies in swine with anal atresia]

33 piglets with anorectal malformations were investigated histologically. 24 animals were male, 9 female. 18 piglets had high deformities with recto-urethral, respectively recto-vaginal fistulas. 15 animals had low deformities. In all animals we were able to demonstrate a sphincter internus muscle and a sphincter externus muscle. The sphincter internus muscle was localised around the fistula. These fistulas also had other characteristics of a normal anal opening.

Chromosomal evaluation of a ewe lamb with atresia ani vaginalis

Chromosomes of a ewe lamb born with atresia ani vaginalis were examined after a 72-hour culture of peripheral whole blood. The 2n number of chromosomes was 54,XX, with no apparent deviation from normality. Pedigree analysis of the ewe lamb indicated that her sire and dam were only slightly related (Rsd = 0.59%); therefore, the amount of inbreeding of the lamb was small (Fx = 0.30%).

Anatomic predisposition to perianal fistulae formation in the German shepherd dog

Gross and microanatomic features which may predispose the German Shepherd Dog to perianal fistulae formation were studied in 2 groups of clinically healthy dogs: a predisposed group (German Shepherd Dogs) and a control group comprising breeds not ordinarily affected by perianal fistulae. The dimensions of the anal crypts (depth, base width, and length), measured and compared statistically between samples, identified no significant variation between groups (P greater than 0.05). Major tissue components of the anal canal were measured microscopically and were similarly evaluated: epithelial height in each zone, thickness of the lamina propria in each zone, thickness of the internal and external anal sphincter muscles, and density of the circumanal, sebaceous, and apocrine sweat glands. The only significant finding was an increase in density of apocrine sweat glands in the zona cutanea in the pre-disposed dog group. In a semiquantitative analysis of the inflammatory responses frequently seen in the anal glands, more mature fibroplasia was seen in the German Shepherd Dogs, indicating that inflammation was more longstanding in this group.

Results of surgical excision of perianal fistulas in dogs

Eighty-seven dogs that had perianal fistulas diagnosed at the Veterinary Medical Teaching Hospital, University of California, Davis, were treated by excision of the diseased tissues and bilateral anal sacculectomy. Males were affected more often than females (66 to 21), and the German Shepherd Dog was the predominant breed (59 of 87). Information from owners regarding long-term postoperative progress was available for 41 dogs. Twenty-two of the 41 dogs had been euthanatized, 15 (36.6%) because of complications related to perianal fistulas and 7 because of unrelated causes. The mean postoperative period, ie, from the time of surgery to the time of euthanasia, was 34.7 months (range, 1 to 82 months). The remaining 19 dogs were examined after a mean postoperative period of 42.3 months (range, 13 to 100 months). Postoperative complications included development of clinically evident fistulas in 23 of the 41 dogs (56.1%), lack of normal continence (26.8%), tenesmus (19.5%), flatulence (17.1%), and anal stricture (14.6%). Twenty-one of the 41 dogs (51.2%) were judged by their owners to be satisfactory pets or to have been satisfactory pets before euthanasia for unrelated reasons

Cryosurgical treatment of cancerous and noncancerous diseases of dogs, horses, and cats

Cryosurgery was used to treat a variety of cancerous and noncancerous diseases in dogs, horses, and cats. Follow-up evaluation on 52 animals revealed an overall "no recurrence" rate of 61%. Among the animals with no recurrence were 12 of 17 with cutaneous lesions and 5 of 8 (horses) with sarcoids. Seven of 10 dogs with anal fistulas healed after cryosurgery, but 2 had recurrence of the disease. Treatment of invasive neoplasms of the oral and nasal cavities was not successful. Side effects and complications were minimal.