Mohs micrographic surgery: a technique for total margin assessment in veterinary cutaneous oncologic surgery.

Mohs micrographic surgery (MMS) is the gold standard for the excision of locally invasive cutaneous malignancies in human dermatological surgery. Using a unique horizontal sectioning technique, MMS enables 100% surgical margin assessment and provides the lowest recurrence rates for locally invasive tumours. The purposes of this preliminary study were to explore the feasibility of application of MMS in the veterinary setting and to establish practical advantages and limitations of its use in a pilot programme. It was hypothesized that MMS technique could provide 100% tumour margin assessment using frozen and/or formalin-fixed horizontal histopathologic sections. Tumour excision and colour-coded mapping were performed, and specimen tissue was fixed using either frozen sections or formalin-fixed sections. Horizontal sections were assessed for quality and presence and location of neoplastic cells based on the mapped orientation. The MMS technique was used in the excision of six squamous cell carcinomas and five mast cell tumours. In all cases, the MMS permitted 100% tumour margins examination.

Deionised water as an adjunct to surgery for the treatment of canine cutaneous mast cell tumours.

Medical records of 55 dogs with a diagnosis of cutaneous mast cell tumour were reviewed. Twenty-seven of the dogs were treated with surgery plus deionized water and the remaining 28 with surgery alone. A survival analysis was performed to determine whether deionized water, as an adjunct to surgery for cutaneous mast cell tumour, affected survival time or time to tumour recurrence. Dogs in which mast cell tumour recurred had a significantly shorter survival time compared with dogs with no recurrence (P = 0.05), regardless of the method of treatment. A significant negative association between tumour recurrence and method of treatment (P = 0.0097) and clinical stage (P = 0.0223) was observed. Dogs treated with surgery and deionized water had a significantly shorter time to recurrence of their mast cell tumour (P = 0.0113). Based on these results, deionized water does not appear to be beneficial in prolonging survival time or time to tumour recurrence for dogs with cutaneous mast cell tumours.

Immunohistochemical and clinical evaluation of p53 in canine cutaneous mast cell tumors.

One hundred twenty-six cutaneous mast cell tumors obtained by excisional biopsy from 106 dogs were evaluated using immunohistochemical staining for the presence of p53 protein. A standard avidin-biotin immunohistochemical protocol was used incorporating a polyclonal antibody of rabbit origin (CM-1) as the primary antibody. Histopathologic grading of tumors was performed on hemotoxylin and eosin-stained samples. There was a significant difference in the percentage of cells staining positive for p53 for the histopathologic grades (P = 0.0005). Grade III tumors had a significantly greater p53 content than did grade I or II tumors (P < 0.05). Clinical data obtained retrospectively was available for 54 dogs. Tumor recurred in 19 of 54 (35.2%) dogs. Twenty-nine dogs died by the end of the study; 9 of 29 (31.0%) died of mast cell tumor disease. Histopathologic grade showed a significant negative association with survival time. Both clinical stage and histopathologic grade showed a significant negative association with time to recurrence. The percentage of cells staining positive for p53 did not significantly improve the forward analysis. Immunohistochemical detection of p53 did not appear useful in characterizing the clinical association between cutaneous mast cell tumor cellular features and survival time or time to tumor recurrence in dogs.

Prepubic urethrostomy for permanent urinary diversion in two Vietnamese pot-bellied pigs.

Two Vietnamese pot-bellied pigs were evaluated because of disruption of the distal portion of the urethra. In 1 pig, disruption was a complication of castration; in the other, disruption was associated with a stricture at the junction of the membranous and penile portions of the urethra. Prepubic urethrostomy was performed in the first pig, because the urethra and penis had been damaged extensively during castration and primary repair of the urethra was not considered possible. Prepubic urethrostomy was performed in the second pig, because the stricture was too close to the vesicourethral junction for perineal urethrostomy to be successful. Both pigs recovered without complications and maintained urinary continence. Lack of tension at the urethrostomy site, atraumatic tissue handling, spatulation of the urethral orifice, and accurate apposition of the urethral mucosa to the skin margin are essential to maintain urinary continence and to prevent stricture of, and urine-induced dermatitis around, the urethrostomy site.

Pyovagina and stump pyometra in a neutered XX sex-reversed beagle: a case report.

An 18-month-old, neutered male beagle presented with acute abdominal signs and a suppurative infection of the urogenital tract. Chromosomal sex was female (78, XX), gonadal sex was male (testicles), and phenotypic sex was ambiguous, with evidence of both male and female duct systems. The internal and external genitalia consisted of epididymides, an underdeveloped uterus with an immature spermatic cord, communication between the uterus or cranial vagina and the membranous urethra, a urethrographically male urethra, a hypoplastic os penis, and a hypoplastic penis with hypospadia. Based on these findings and the familial history of a similarly affected litter mate, the dog was diagnosed as having the XX male syndrome with pyovagina and uterine stump pyometra. Radiographic and ultrasonographic investigations are described, and abnormalities of chromosomal sex, gonadal sex, and phenotypic sex are discussed.

Liposarcoma associated with a glass foreign body in a dog.

An 11-year-old spayed female mixed-breed dog was referred for evaluation of a mass on the right forelimb of 4 months' duration. Cytologic examination of a fine-needle aspirate of the mass resulted in a diagnosis of liposarcoma. The 3 x 3 x 1.5-cm firm mass was surgically removed. Histopathologic observations confirmed the diagnosis of liposarcoma. During processing, a 1 x 0.8-cm piece of glass was found within the mass. Association between a glass foreign body and liposarcoma is discussed.

Large bowel transit times using radiopaque markers in normal cats.

Seven normal, young adult, female cats each had its colon evacuated with warm-water enemas (at 24 hours, 12 hours, and one hour) before oral administration of a gelatin capsule containing 20 radiopaque markers to determine normal colonic transit times. Abdominal radiographs were taken twice daily until all markers were expelled. There were no significant differences between animals or trials (p = 0.05 or less). Markers accumulated in the first section of large bowel within eight hours. Evacuation from the colon took another 40 hours. Cecum (right side midline), left side midline, and rectum were defined radiographically. This study establishes large bowel transit times in normal cats and provides the basis for similar evaluation in constipated cats.

Perineal herniorrhaphy: perioperative data from 100 dogs.

One hundred dogs (83 intact males, 15 castrated males, and two intact females) underwent 110 perineal herniorrhaphy procedures. Mixed-breed dogs (n = 32), miniature poodles (n = 14), Boston terriers (n = 11), and Pekingese (n = 9) were represented most frequently. Perineal swelling (n = 48) and a perineal defect on rectal palpation (n = 31) were common clinical signs. Twenty dogs had urinary bladder retroflexion and were significantly more likely to have elevated serum urea nitrogen and creatinine concentrations, hyperkalemia, hyperphosphatemia, and neutrophilic leukocytosis. Only five of 43 dogs evaluated radiographically had prostatomegaly. Of 30 dogs receiving oral barium, all had rectal deviation. The most frequent complications during the hospitalization period were incisional (n = 35), followed by rectal prolapse (n = 9), tenesmus (n = 8), and depression (n = 8). Fifty-six of 70 dogs with follow-up had no complications.

Omental pedicle used to manage a large dorsal wound in a dog.

An eight-year-old miniature schnauzer was presented with full thickness skin necrosis over most of the back, probably caused by a chemical burn. Management consisted of debridement, bandaging, hyperbaric oxygen therapy, topical application of tris-EDTA and oral administration of antimicrobials. A pedicle created from the greater omentum was used to fill the wound and provide a vascular bed for a full thickness meshed skin graft. Despite epidermal loss from the majority of the graft, the wound healed with acceptable appearance and function. This is the first clinical case described in the veterinary literature using an omental pedicle in prepare a free skin graft bed.

Primary rib tumors in 54 dogs.

Fifty-four dogs with primary tumors of the rib were evaluated. Thirty-four dogs had osteosarcomas, 15 dogs had chondrosarcomas, three dogs had hemangiosarcomas, and two dogs had fibrosarcomas. Forty-nine dogs had en bloc excision. Within the osteosarcoma group, nine animals received postoperative adjuvant chemotherapy. These animals had significantly longer median disease-free intervals (225 days) and median survival times (240 days) than dogs with osteosarcoma treated by surgery alone (median disease-free interval, 60 days; median survival, 90 days). Chondrosarcoma had a better prognosis (median disease-free interval, 1,080 days; median survival, 1,080 days) than osteosarcoma, hemangiosarcoma, or fibrosarcoma of the rib. Age, weight, sex, number of ribs resected, tumor volume, and total cisplatin dose did not influence survival nor disease-free interval.

Tracheostomies in the management of canine and feline upper respiratory disease.

Permanent tracheostomy and tube tracheostomy are both important for patients' supportive care; neither procedure cures any particular disease. Permanent tracheostomy is indicated to by-pass upper airway obstructions in the ambulatory patient needing an alternate airflow route for a long period. Temporary or tube tracheostomy is indicated to facilitate anesthetic management during head and neck surgery, long-term mechanical ventilation, and emergency patient care. Perioperative problems are expected with both procedures. Obstruction of the tube or stoma is the most common life-threatening problem. Most problems can be circumvented with careful and diligent patient management.

Esophagotomy closure in the dog. A comparison of a double-layer appositional and two single-layer appositional techniques.

Esophagotomies were performed on 36 dogs and closed with 3-0 polydioxanone in double-layer simple interrupted, single-layer simple interrupted, or single-layer simple continuous patterns. The operative time was shortest for single-layer simple continuous closure, followed by single-layer simple interrupted and double-layer simple interrupted, respectively. Three dogs with each suture pattern were euthanatized at hours 0 and 1, and days 4 and 28 after surgery. The esophagotomy incisions were subjected to bursting strength testing and examined microscopically. The bursting wall tension was higher for all three suture pattern groups at 28 days than at 0 and 1 hour. The double-layer closure had higher bursting wall tension than the single-layer closures at 0 hour and 4 days. Single-layer simple continuous closure had the lowest bursting wall tension for each time period. Single-layer simple interrupted closure had the highest bursting wall tension at 28 days. Microscopic examination revealed close approximation of tissue planes for the double-layer closure and mucosal eversion for the simple interrupted and simple continuous single-layer closures. Healing was superior histologically with the double-layer closure.

Clinical evaluation of axial pattern skin flaps in dogs and cats: 19 cases (1981-1990).

Nineteen axial pattern skin flaps were used in 16 dogs and cats to provide skin for repair of extensive cutaneous defects. Retrospective evaluation of medical records was used to determine percentage flap survival, postoperative complications, and long-term outcome of axial pattern skin flaps. The most common indication for use of axial pattern flaps was to augment wound closure following tumor resection (n = 7). Other indications included trauma (n = 5), chronic nonhealing wounds (n = 4), urine-induced cellulitis (n = 1), idiopathic dermal necrosis (n = 1), and chronic lymphoplasmocytic dermatitis (n = 1). Mean flap survival (+/- SD) was 96% (+/- 8). Postoperative complications included wound drainage (n = 15), partial dehiscence of the sutured flap (n = 7), distal flap necrosis (n = 6), infection (n = 3), edema (n = 3), and seroma formation (n = 2). After a median follow-up time of 5 months, evaluation of animals indicated that surgery provided successful wound reconstruction with good cosmetic results. Reconstruction of large cutaneous defects is facilitated by axial pattern flap application regardless of cause of wound. Postoperative complications are common but amenable to standard wound management techniques such as drain placement and surgical debridement of devitalized distal flap skin.

Aspirated dental calculus in a dog.

Aspiration of a dental calculus, with lodgement of the calculus in a mainstem bronchus, was identified in a dog after dental prophylaxis. The calculus was located by use of radiography and bronchoscopy, and was removed via thoracotomy. Aspiration is a possible complication of dental prophylaxis. Endotracheal intubation with a properly inflated cuff, and thoroughly rinsing the oral cavity after prophylaxis, may avoid this and similar complications.

Resection of a cervical tracheal bronchus in a foal.

A 3-day-old Thoroughbred foal developed a large, air-distended, midcervical swelling that was diagnosed as a congenital tracheal bronchus with associated ectopic lung tissue. Clinical signs consisted of a compressible air-filled sac that enveloped the trachea. The nature and extent of the defect were evaluated endoscopically and radiographically. Surgical resection of the bronchus and associated air-filled sac resulted in a functionally and cosmetically acceptable outcome.

Tracheostomy.

Tracheostomies are performed to bypass life-threatening obstructions of the upper airway or to facilitate surgical procedures in the head and neck region. Neither tube tracheostomy nor permanent tracheostomy is a cure for any particular disease; however, both can be important for patients' supportive or palliative care. Perioperative problems are anticipated with either tube tracheostomy or permanent tracheostomy. Obstruction of the tube or stoma is the most common and devastating problem. Careful and diligent management of tracheostomy patients can circumvent many problems and allow the patient to breath with less difficulty.

Tracheal resection and reconstruction.

Tracheal resection and reconstruction may be required in patients with tracheal obstruction due to foreign bodies, trauma, parasitic granulomas, or tracheal tumors. Primary end-to-end anastomosis is the best means of reconstruction after the diseased tissue is resected. If anastomosis can be accomplished without excessive tension, few complications occur. However, if there is tension at the anastomotic site, the incision may separate, causing scar tissue to form and stenosis to occur. Many techniques may be used to prevent anastomotic stenosis, including tracheal mobilization, tension-relieving sutures, and head-neck immobilization. Grafts or prosthesis may be required when primary end-to-end anastomosis is impossible. More frequent complications are associated with the use of grafts and prostheses than with end-to-end anastomosis. These most commonly include stenosis, prosthesis migration, and erosion of adjacent blood vessels.

Tracheal collapse.

Tracheal collapse, one form of tracheal obstruction, is classically described as occurring in middle-aged or older toy breed dogs with a history of chronic "goose-honk" cough. Many dogs with tracheal collapse fit this description, but others are young and may wheeze, hack, or have no cough at all. Patients with a history and physical examination compatible with tracheal collapse are definitively diagnosed based on the findings of the following respiratory tract examinations: inspiratory/expiratory radiographs, fluoroscopy, culture and susceptibility, and a thorough endoscopic evaluation. Prosthetic ring tracheoplasty relieves many of the signs of tracheal obstruction but does not cure the disease. Early diagnosis and treatment are expected to give the dog a better quality life. Following prosthetic ring tracheoplasty, most dogs are more active, breathe easier, cough less, and require less medical treatment for respiratory disease.

Use of ultrasonography to diagnose Sertoli cell neoplasia and cryptorchidism in a dog.

Unilateral cryptorchidism and Sertoli cell tumor in the descended testis were provisionally diagnosed by use of ultrasonography in a 7-year-old Keeshond. The left testis was thought to have degenerated, but ultrasonography of the scrotum did not reveal evidence of testicular or epididymal tissue. The contralateral testis contained a hypoechoic mass believed to be a testicular tumor. Surgery and histopathologic findings confirmed the diagnosis. Ultrasonography of the scrotum and its contents should be considered for use in animals with suspected testicular neoplasia and/or degeneration.