Surgical description and outcome of ultrasound-guided minimally invasive parathyroidectomy in 50 dogs with primary hyperparathyroidism.

OBJECTIVE: To describe the surgical technique and clinical outcome of minimally invasive parathyroidectomy for primary hyperparathyroidism (PHPT) in the dog. ANIMALS: Fifty client-owned dogs with PHPT that underwent minimally invasive parathyroidectomy. STUDY DESIGN: Retrospective cohort study. METHODS: An ultrasound-guided mini lateral approach was made via a plane established between the sternocephalicus muscle and sternohyoideus muscles to expose the thyroid gland and enlarged parathyroid gland. Abnormal parathyroid glands were removed en bloc via partial thyroidectomy. The technique for bilateral disease was similar, the skin incision was made on midline and moved laterally to develop the above-mentioned plane of dissection. Age, sex, breed, bodyweight, ultrasound findings, histopathological diagnosis, surgical time, preoperative clinical signs, and clinical outcome were extracted from the records for descriptive statistics. RESULTS: A total of 62 glands were surgically removed, including 17 hyperplastic glands (17/62, 27.4%), 34 adenomas (34/62, 54.8%), and two carcinomas (2/62, 3.2%). Hypercalcemia resolved shortly after surgery in 44 dogs (44/45, 97.8%). One dog had recurrent hypercalcemia (1/45, 2.2%), one dog had persistent hypercalcemia (1/45, 2.2%), two dogs had permanent hypocalcemia requiring life-long calcitriol supplementation (2/45, 4.4%), and one dog died from clinical hypocalcemia (1/45, 2.2%). CONCLUSION: Minimally invasive parathyroidectomy was associated with a low morbidity and led to favorable outcomes in 44/45 dogs in this series. CLINICAL SIGNIFICANCE: The results of this study supports the use of minimally invasive parathyroidectomy to treat PHPT in dogs.

Balloon catheter as an extraction device for caudal vena cava adrenal tumor thrombectomy in a dog: A case report.

OBJECTIVE: To report the use of a balloon catheter as an extraction device for a posthepatic caval thrombus in a dog with a right adrenal tumor. ANIMALS: Twelve-year-old male neutered Chihuahua mix dog. STUDY DESIGN: Case report METHODS: The dog presented for the evaluation of a hepatic mass. Computed tomography of thorax and abdomen was performed, and a right lateral liver lobe mass and a right adrenal mass were noted. The adrenal mass had a caval thrombus extending almost to the level of the right atrium. Traditional methods of tumor thrombectomy were unsuccessful. Extraction of the thrombus was facilitated by passing a balloon catheter through the caudal vena cavotomy until it was cranial to the thrombus, inflating the balloon and slowly withdrawing the catheter. RESULTS: A malignant pheochromocytoma was diagnosed on histology. The dog had a subjectively assessed good quality of life until it was euthanized 118 days postoperatively for acute dyspnea. CONCLUSION: Balloon catheter-assisted thrombectomy was successful in removing an extensive caval thrombus that was otherwise difficult to extract via conventional methods. This technique can be considered in cases with extensive tumor thrombus either as a method of choice or when other methods of thrombus extraction have failed.

Evaluation of the superior and inferior labial musculomucosal flaps in cats: An angiographic study and case series.

OBJECTIVE: To evaluate the angiosomes of the superior and inferior labial arteries in the cat and describe the use of a musculomucosal axial pattern flap incorporating each artery for reconstruction of palatal defects in cats. STUDY DESIGN: Cadaveric study and a series of two clinical cases. SAMPLE POPULATION: Five feline cadavers and two client-owned cats. METHODS: The common carotid arteries of five feline cadavers were injected with barium sulfate. Radiographs of excised tissue specimens were examined to map the location of the superior and inferior labial arteries and to visualize each angiosome available for an axial pattern flap. Labial musculomucosal flaps were utilized to reconstruct palatal defects in two live cats. RESULTS: The superior and inferior labia were predominantly perfused by the superior and inferior labial arteries, respectively, and the angiosome of each artery encompassed the majority of its respective labium. Comparative positive contrast angiograms revealed the vascular supply was located within the musculomucosal layer. Reconstruction of recurrent palatal defects utilizing musculomucosal flaps based on these angiosomes in two clinical cases was successful with complete survival of the flaps. CONCLUSION: The upper and lower lips were found to have robust vascular supplies within the musculomucosal layer which can support musculomucosal axial pattern flaps. CLINICAL SIGNIFICANCE: This information provides the veterinary surgeon with additional surgical options for reconstruction of central and caudal palatal defects in the cat.

Arterial supply to the scrotum: A cadaveric angiographic study.

OBJECTIVE: To determine the dominant arterial supply to the scrotum. STUDY DESIGN: Experimental anatomic study. ANIMALS: Intact male canine cadavers (n = 10). METHODS: Barium sulfate was injected into the internal iliac artery (n = 7) or into the pudendoepigastric trunk (n = 3). The perineal, scrotal, and prescrotal skin was sharply dissected from cadavers and radiographed. Angiograms were subjectively reviewed by 3 investigators. RESULTS: Angiograms were completed successfully in all 10 dogs, with no difference between frozen and fresh cadavers. The dominant blood supply to the scrotum was consistently identified as arising from the ventral perineal arteries, originating from the internal pudendal arteries, coursing ventrally and cranially toward the caudal scrotum before terminating as the dorsal scrotal arteries (n = 7). The blood supply to the cranial scrotum was more limited (n = 3) as only the cranial border of the scrotum was perfused by the ventral scrotal arteries. CONCLUSION: Based on this anatomic perfusion study, the dorsal scrotal arteries appear to supply a larger area than the ventral scrotal arteries. CLINICAL SIGNIFICANCE: These results provide evidence to justify further consideration of a scrotal flap using the caudal perineal skin as the main cutaneous pedicle to reconstruct defects located on the caudal, medial, and lateral thighs in dogs. Such a flap should be based on the caudal blood supply and the base of this flap should be located caudal to the scrotum to preserve its main blood supply.

Identification of cutaneous arteries of the perineal and caudal thigh region: A cadaveric study in 12 cats.

OBJECTIVE: To describe the location of the dorsal perineal artery in cats and identify landmarks for axial pattern flaps based on this vessel. STUDY DESIGN: Anatomic study. ANIMALS: Twelve feline cadavers. METHODS: Nonselective barium sulfate angiography was performed via injection of the descending aorta. Skin excised from the perineum and thighs was evaluated via gross inspection and radiography to identify angiosomes. RESULTS: The dorsal perineal artery had a robust angiosome on the caudal thigh in 10 of 12 cadavers. The artery exited the ischiorectal fossa along the muscular furrow between the biceps femoris and semitendinosus muscles and passed sagittally toward the popliteal fossa in those 10 specimens. All cadavers had a consistent angiosome based on the ventral perineal artery, which was located on the caudomedial thigh. All cadavers also had a consistent angiosome from a cutaneous branch of the popliteal artery, which traveled in a distal to proximal direction starting at the popliteal fossa. CONCLUSION: The dorsal perineal artery had a large cutaneous angiosome on the caudal thigh, which was consistent in most cats. The ventral perineal artery and cutaneous branch of the popliteal artery had consistent but smaller cutaneous angiosomes. CLINICAL SIGNIFICANCE: The axial pattern flaps of the cutaneous branches of the dorsal and ventral perineal arteries and the popliteal artery provide a robust arterial blood supply to the skin of the perineum and the caudal thigh. These three flaps may therefore have adequate vascular supply to consistently survive in most cats.

Evaluation of the Superior Labial Musculomucosal Flap in Dogs: An Angiographic Study and Case Report.

OBJECTIVE: The aim of this study was to evaluate the angiosome of the superior and inferior labial arteries within the superior and inferior labia and to describe superior and inferior labial musculomucosal axial pattern flaps that can be used for intra-oral wound reconstruction. This study also presents the clinical use of a superior labial musculomucosal flap in a dog. MATERIALS AND METHODS: The common carotid arteries of six canine cadavers were injected with barium sulphate. The skin of the face and labial mucosa was removed and radiographed to study the vascular supply of the superior and inferior labia. RESULTS: The angiograms in all dogs demonstrated that the superior and inferior labial arteries were located within the musculomucosal layer of the labia. At the junction of the rostral and caudal half of the upper lip, extensive choke anastomoses joined the angiosome of the infra-orbital artery. The inferior labial artery perfused the caudal half of the lower labium and had extensive choke anastomoses with the middle and rostral mental arteries. CLINICAL SIGNIFICANCE: The musculomucosal flaps of the superior and inferior labia contain a rich arterial blood supply, which suggests that these flaps may survive in live dogs. The superior labial musculomucosal flap was successfully used to reconstruct a large cleft palate in a single clinical case.

Benefits of pre- and intraoperative planning for tibial plateau leveling osteotomy.

OBJECTIVE: To determine (1) if preoperative and intraoperative osteotomy planning increases the likelihood that a surgeon will achieve a centered osteotomy during tibial plateau leveling osteotomy (TPLO) and (2) if that centered osteotomy reduces the risk of tibial tuberosity (TT) fractures. STUDY DESIGN: Retrospective case series. ANIMALS: Dogs (n = 406) with cranial cruciate ligament that had TPLO (n = 468). METHODS: Medical records (2007-2010) and radiographs of dogs that had TPLO were reviewed. Osteotomies from Group A (pre and intra-operative planning) were compared to Group B (free-hand osteotomy only) investigating the influence of osteotomy planning as well as 21 other variables, looking for any other confounding variables that may also contribute to TT fractures. Data were analyzed with logistic regression and χ(2) analysis. RESULTS: Actual osteotomies were closer to the centered-osteotomy position in Group A than in Group B (P ≤ .01). TT fractures occurred in 20 cases (4.3% overall). Group A had 0 fractures out of 172 surgeries and Group B had 20 fractures out of 296 surgeries (6.8%). Five variables were found to increase the risk of TT fractures: lack of osteotomy planning, bilateral same-session surgeries, osteotomy gap, anti-rotational pin location, and decreased tibial crest width at the insertion of the patellar ligament (P ≤ .05). CONCLUSIONS: Dogs that had osteotomy planning had a more centered osteotomy position and a reduced risk of developing TT factures.

Histomorphometric analysis and regional variations of full thickness skin grafts in dogs.

OBJECTIVE: To (1) compare thickness of the epidermis and dermis of anatomically different donor sites in dogs, and (2) evaluate hair follicle damage during full thickness skin grafts (FTSG) preparation from anatomically different donor sites. Another objective was to compare the extent of agreement between gross and histologic quality of graft preparation. STUDY DESIGN: Ex vivo study. ANIMALS: Healthy Beagle dogs (n = 12). METHODS: Skin samples were harvested from fresh cadavers free of gross dermatopathology and FTSG prepared. Regional, epidermal and dermal thickness, and hair follicle density in intact skin and FTSG specimens from different regions were determined by histomorphometric analysis. Hair follicle density in intact skin and FTSG specimens, and skin thickness measurements were compared among regions. RESULTS: Mean epidermis and dermis thickness of the dorsal lumbar and lateral neck regions were significantly greater when compared with other sites. Total hair follicle (superficial and deep dermis) densities were significantly less in prepared FTSG versus intact skin specimens. The dorsal lumbar region had the highest hair follicle density. CONCLUSIONS: Thickness of the epidermis and dermis is dependent on body region. Hair follicle density in the FTSG specimens was decreased compared with intact skin specimens, which may affect hair regrowth in FTSG.

Hilar liver resection in dogs.

OBJECTIVE: To describe hepatic vasculobiliary anatomy important to hilar liver lobe resection in the dog. STUDY DESIGN: Experimental study. ANIMALS: Canine cadavers (n=7). METHODS: The vasculobiliary system of 7 fresh canine livers was injected with a polymer. The parenchyma was dissected at the level of the hilus to determine the vascular and biliary supply to each liver lobe, and then macerated with a corrosion preparation. The information gathered was used to describe a surgical approach for hilar liver lobe resection. RESULTS: Each liver lobe had a single hepatic artery and biliary duct. The location of these structures was consistent, although minor variations existed (dorsal versus ventral to the lobar portal vein) in the left lateral lobe and papillary process in 2 specimens. Most liver lobes (34/49) were supplied by 1 lobar portal vein and drained by 1 lobar hepatic vein (39/49). The location of the portal and hepatic veins was consistent among specimens. CONCLUSIONS: The left division is the most mobile of the liver lobes and each lobe can be removed separately or en bloc. Because of the location of the hepatic veins, the central division is best removed as a single unit. The right lateral lobe can be removed individually or together with the caudate process. The papillary process is removed by itself. CLINICAL RELEVANCE: A hilar liver lobectomy technique can provide an alternative approach to conventional procedures for tumors that encroach upon the hilus of the liver.

Rectus abdominis free muscle flap for reconstruction in nine dogs.

OBJECTIVE: To evaluate the clinical use and outcome of a rectus abdominis microvascular free flap for wound closure in dogs. STUDY DESIGN: Retrospective case series. ANIMALS: Dogs (n=9) with complex extremity or oral wounds. METHODS: Medical records (2002-2006) of dogs that had a rectus abdominis free tissue transfer to close an extremity or oral wound were reviewed. RESULTS: Nine dogs were identified: 5 had distal extremity wounds, 3 had oral palatal defects, and 1 had a large hygroma excised. A rectus abdominis free tissue transfer with a caudal epigastric vascular pedicle was successfully used for management of these wounds. No major complications occurred with the donor site and a good cosmetic and functional outcome occurred in all dogs. CONCLUSION: The rectus abdominis is a versatile muscle that can be used for reconstructing cutaneous and oral defects with repeatable success. CLINICAL RELEVANCE: Free tissue transfer of the rectus abdominis muscle is a clinically useful technique for closure of a variety of difficult soft tissue wounds.

Medical and surgical management of traumatic elbow luxation in a juvenile ferret.

Elbow luxation is a common orthopedic injury in the ferret. The injury is usually caused by trauma but can also occur spontaneously. The most successful treatment involves a combination of surgical and medical intervention. Surgical treatment includes open reduction of the elbow joint and stabilization with orthopedic implants. Medical treatment includes external coaptation, analgesia, and prevention of infection. Owner compliance also plays an important role in return to full function of the luxated ferret elbow joint.

Surgical approaches to recipient vessels of the fore- and hindlimbs for microvascular free tissue transfer in dogs.

OBJECTIVE: To develop and evaluate surgical approaches to the arteries and veins of the fore- and hindlimbs for use as potential recipient vessels for free tissue transfer. STUDY DESIGN: Experimental anatomic study. SAMPLE POPULATION: Canine cadavers (11): 2 preserved and 9 fresh cadavers. METHODS: Fore- and hindlimbs from 1 preserved cadaver injected with a pigmented silicone/barium mixture, through the common carotid artery and external jugular vein, were cut in 1 cm cross-sections. Tissue sections were used to identify the location of vessels >1 mm that could be used as recipient vessels for free tissue transfer. The other preserved cadaver was used to develop surgical approaches to these vessels. Three surgeons evaluated the written descriptions and illustrations for these approaches using fresh cadavers. Modifications to the surgical approaches were made based on recommendations from these surgeons. RESULTS: Six approaches were developed to isolate forelimb recipient vessels: palmar access, distal medial antebrachial, mid-antebrachial, proximal antebrachial, distal humeral, and mid-humeral vascular access. Twelve approaches were developed to isolate recipient vessels of the hindlimb: plantar access, dorsal tarsal, cranial distal tibial, craniomedial distal tibial, lateral distal tibial, medial distal tibial, medial femorotibial, lateral distal femoral, medial femoral, proximal medial femoral, groin, and proximal lateral femoral vascular access. CONCLUSIONS: Six forelimb and 12 hindlimb sites were identified for surgical access to recipient vessels (>1 mm diameter) suitable for use in free tissue transfer for wound reconstruction. CLINICAL RELEVANCE: For reconstruction of complex wounds of the extremities of dogs, surgeons should consider use of readily accessible recipient vessels that would allow for free tissue transfer to the fore- and hindlimbs.

Evaluation of primary critical ischemia time for the deep circumflex iliac cutaneous flap in cats.

OBJECTIVE: To evaluate the primary critical ischemia time for the deep circumflex iliac (DCI) cutaneous flap in cats. STUDY DESIGN: In vivo model. ANIMALS: Thirteen young adult female cats. METHODS: An island skin flap was created on the right side of each cat based on the angiosome of the ventral branches of the DCI vessels. The cats were randomly assigned to a flap ischemia time ranging from 1 to 3 hours in 10-minute intervals. Microvascular clamps were used to occlude the artery and vein for the designated time. Flaps were sutured into position after the ischemic period. On day 3, fluorescein dye was administered and the flaps were evaluated under ultraviolet light to assess percent area of perfusion. On days 7 and 14, the percent area of survival was determined for each flap based on cutaneous morphometry. RESULTS: All flaps had 100 percent area of survival throughout the study. On day 3, all flaps fluoresced uniformly compared with the surrounding skin. On days 7 and 14, all flaps were uniformly viable as confirmed by skin color, consistency, bleeding, and hair re-growth. CONCLUSION: The DCI cutaneous flap in cats can withstand up to 3 hours of ischemia with predictable survival. CLINICAL RELEVANCE: In a clinical setting, high success rates can be expected with microvascular transfer of the DCI cutaneous flap in cats when the ischemia time is <3 hours and precise surgical technique is used.

Surgical approaches to recipient vessels of the head and neck for microvascular free tissue transfer in dogs.

OBJECTIVE: To develop and evaluate surgical approaches to the arteries and veins of the head and neck for use as potential recipient vessels for free tissue transfer. STUDY DESIGN: Experimental anatomic study. SAMPLE POPULATION: Eleven canine cadavers; 2 preserved cadavers and 9 fresh cadavers. METHODS: The head and neck of one preserved cadaver injected with pigmented silicone/barium, through the common carotid artery and external jugular vein, was cut in 1 cm sagittal sections and cross-sections. These tissue sections were used to identify the location of recipient vessels >1 mm that could be used as recipient vessels for free tissue transfer. The other preserved cadaver was used to develop surgical approaches to these vessels. Three board certified surgeons evaluated the written descriptions and illustrations of the approaches using fresh cadavers. Modifications to the surgical approaches were made based on recommendations from these surgeons. RESULTS: Seven approaches were developed to isolate recipient vessels of the head and neck region. The infraorbital, temporal, and sublingual approaches were easily performed and provided excellent access to the vessels in the region. The approach to the caudal auricular vessels was found to be more difficult but modification of the approach resolved this problem. Access to the facial artery was difficult; it was consistently <1 mm in diameter and thus its use could not be recommended. The approach to the vessels in the cervical region was easily performed. Because of the large size of the external jugular vein and the common carotid artery, end-to-side anastomosis of the donor to recipient vessels is necessary. The large superficial cervical vessels were easily accessed by a lateral shoulder approach. CONCLUSIONS: Surgical approaches to potential recipient vessels of the head and neck were consistently achieved and provided relatively easy access to the vessels. Clinical Relevance- The surgical approaches described in this report can be used to isolate arteries and veins of the head and neck that are >1 mm in diameter. These vessels are suitable for use as recipient vessels for free tissue transfer for reconstruction of complex wounds of the head and neck.

Deep circumflex iliac cutaneous free flap in cats.

OBJECTIVE: To develop and assess the survival of a microvascular cutaneous free flap based on the ventral branch of the deep circumflex iliac (DCI) artery and vein in cats. STUDY DESIGN: Experimental study. ANIMALS: Phase 1: 6 feline cadavers; Phase 2: 2 adult cats; Phase 3: 10 adult cats. METHODS: Phase 1: Selective angiographic study of the deep circumflex iliac artery was completed in 6 feline cadavers. After injection of the DCI artery with barium, high-detail radiographs were made of skin flaps harvested from the lateral flank and thigh region. The extent of the cutaneous angiosome was mapped with regard to the underlying anatomical landmarks. Phase 2: An island flap based on anatomic boundaries of the DCI angiosome derived from phase 1 of the study was elevated in 2 cats. Flaps were observed for 3 weeks for survival. Phase 3: Free skin flaps based on the DCI vessels were harvested in 10 cats and transferred to the dorsal interscapular region. Flaps were evaluated for 2 weeks for survival. Tissue samples were collected for histopathology, and angiograms of the flaps were completed. RESULTS: Phase 1: Angiograms revealed a large primary cutaneous angiosome of the DCI artery located over the lateral femoral region, which extended from the iliac crest to the level of the patella. Phase 2: All island flaps survived for 3 weeks. Phase 3: Six free flaps survived for 2 weeks, and 4 flaps failed completely. Failure of 1 flap occurred because of avulsion of the venous and arterial anastomosis postoperatively. Another cat had intraoperative hemorrhage, which resulted in anemia and hypovolemia and likely caused the flap to fail. The other 2 flaps that failed had poor perfusion intraoperatively and had the longest ischemia times. CONCLUSIONS: The cutaneous DCI free flap in cats may be clinically useful in reconstruction of large cutaneous wounds. The length of ischemia time for successful cutaneous free flap transfer in the cat may be shorter than in other species. CLINICAL RELEVANCE: Large wounds created by trauma or oncologic ablative surgery in cats could be reconstructed with cutaneous microvascular free flap. Additional studies assessing the critical ischemia time of cutaneous flaps in cats and evaluating the use of this flap clinically are needed.

Cutaneopulmonary fistula in a dog caused by migration of a toothpick.

A 6-year-old, neutered male, mixed-breed dog was presented for a chronic draining tract and cough. A contrast fistulogram demonstrated a cutaneopulmonary fistula. Excision of the fistulous tract retrieved a migrating foreign body (i.e., a toothpick) within the tract. Clinical signs resolved 2 weeks following surgery. Foreign body migration is a common problem seen in dogs, resulting in many different clinical syndromes. Definitive surgery depends upon complete removal of the foreign body and the diseased tissue. Sinography is an inexpensive, readily available diagnostic tool that can help define a draining tract and confirm a foreign body.

Microvascular free tissue transfer of the rectus abdominis muscle in dogs.

OBJECTIVE: To assess donor-site morbidity and survival of the rectus abdominis muscle with an overlying skin graft after free tissue transfer to a medial femorotibial defect in dogs. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Phase 1: 6 canine cadavers; phase 2: 7 adult mixed-breed dogs. METHODS: Phase 1: The rectus abdominis muscle was removed from canine cadavers, muscular and vascular dimensions were recorded, and angiography was performed. Phase 2: Muscular transfer was performed through anastomosis of the caudal epigastric artery and vein to the saphenous artery and medial saphenous vein. Transferred tissues were evaluated on postoperative days 3, 6, 10, and 13. Animals were examined daily until euthanasia between postoperative days 31 and 42. Postmortem angiograms were performed and tissues collected for histopathologic evaluation. RESULTS: Phase 1: Appropriate vascular dimensions for microvascular anastomosis were confirmed and surgical technique perfected. Phase 2: Muscular excision produced minimal donor-site morbidity. All muscles survived after microvascular transfer and angiography confirmed vascular patency. All of the skin grafts survived, with one graft undergoing partial necrosis. CONCLUSIONS: The rectus abdominis muscle can be successfully transferred to a medial femorotibial defect and can serve as a bed for acute skin grafting. No significant donor-site morbidity is associated with its removal. CLINICAL RELEVANCE: Microvascular free tissue transfer of the canine rectus abdominis muscle has not been previously described. This technique provides a new alternative for repair of appropriate wounds. Additional studies are needed to define its utility in clinical patients.