Incomplete ossification of the humeral condyle in two Labrador retrievers

Incomplete ossification of the humeral condyle (IOHC) was identified in two Labrador retrievers using computed tomography. Both dogs were non-weightbearing on the affected forelimbs. The dogs were treated by means of a bone screw placed across the humeral condyle. IOHC was originally reported in spaniel and chondrodystrophic breeds. The pathogenesis of the condition remains unknown, but may be related to impaired antebrachial bone growth, similarly to the pathogeneses of elbow dysplasia and radius curvus.     

Efficacy of Polycaprolactone in Maintenance of Bone Defects in Ulnar Osteotomies

Polycaprolactone (PCL), a synthetic polyester, was investigated as an interpositional material to delay bone healing following partial ulnar osteotomies. Bone healing did not occur in 6 of 10 osteotomy sites 8 to 24 weeks following surgery in which a PCL cap was placed over the proximal cut end of the ulna, or in four of six ostectomy sites filled with melted PCL that hardened into a plug. Bone healing occurred in ulnectomy sites in which technical problems in positioning and stabilizing the polymer implants occurred. The PCL was well tolerated by the dogs and was an effective mechanical barrier to tissue bridging when adequately stabilized.     

The repair of segmental bone defects with porous bioglass: an experimental study in goat

This study was exclusively conducted to evaluate healing of surgically created defects on the radius of adult Black Bengal goat after implantation of porous bioglass blocks and compare the process kinetics with normal healing. Twelve Black Bengal goats were divided randomly into two groups: control and experimental group implanted with bioglass blocks. Unicortical bone defects in radius were generated in all animals under aseptic condition. Local inflammatory reaction and healing of wound, radiological investigations, histological studies, oxytetracycline leveling and angiographic studies were performed up to 90th day post-operatively and compared with normal healing. It has been found that extensive new bone formation originating from host bone towards the implant whereas in control, the process was active from both the ends; the defect site appeared as homogenous nonfluorescent area. Thus, porous bioglass promoted bone formation over the entire extension of the defect independent of size of block in comparison to control group.     

Accuracy of radiography, nuclear scintigraphy, and histopathology for determining the proximal extent of distal radius osteosarcoma in dogs

OBJECTIVE--To compare the accuracy of radiography, nuclear scintigraphy, and histopathology for determining the proximal extent of distal radius osteosarcoma in dogs. STUDY DESIGN--Retrospective clinical study. SAMPLE POPULATION--Twenty client-owned dogs taken to Colorado State University with osteosarcoma of the distal radius. METHODS--Medical records of 20 dogs with confirmed osteosarcoma that underwent a limb-salvage procedure were reviewed. Measurements were performed directly from the lateral view of each radius, from both the scintigram and the radiograph, to determine the length of the radius and the distance from the proximal extent of the tumor to the distal radiographic or scintographic extent of the radius. The ratio of distal radial involvement to total radius length was calculated. A similar ratio was also determined using the macroslide, which included the entire portion of bone that was excised during the limb-salvage procedure. All 3 methods of measurement were compared. RESULTS--Nuclear scintigraphy significantly overestimated tumor length when compared with macroslide specimen measurements. Radiography also overestimated tumor length, but these results were not significantly different from macroslide specimen measurements. CONCLUSIONS--Both radiography and nuclear scintigraphy overestimate the extent of distal radius osteosarcoma in dogs when compared with histopathologic macroslides of the same lesions. Nuclear scintigraphy overestimated tumor extent to a larger degree than did radiography. CLINICAL RELEVANCE--Although radiography is a more accurate method of measurement of the extent of distal radius osteosarcoma, because nuclear scintigraphy overestimates tumor length to a greater degree, scintigraphy may provide a larger margin of safety for determining the site of proximal osteotomy during a limb-salvage procedure. However, caution should be taken when utilizing scintigraphy, because this method may overestimate length of radius involved to such an extent as to cause the surgeon to believe that a patient is not a suitable limb-salvage candidate.     

Partial cystectomy for urinary bladder neoplasia: surgical technique and outcome in 11 dogs

Partial cystectomy was performed in 11 dogs with bladder neoplasia (10 with transitional cell carcinoma and one with rhabdomyosarcoma). Between 40 and 70 per cent of the bladder was excised during the partial cystectomies. In eight dogs, all the grossly visible tumour was excised but on histopathological examination of the excised tissue, neoplastic tissue was found to extend to the surgical margins in four of these dogs. A ureteral stoma was excised with the tumour in four dogs necessitating ureteral reimplantation; one dog had both ureteral stomas excised and bilateral ureteral reimplantation. The bladder incision dehisced in two dogs, necessitating a second surgery. Six dogs were polla-kiuric after surgery. Pollakiuria resolved within two months in four dogs and persisted in two dogs. None was incontinent. Local tumour recurrence was suspected in nine dogs based on imaging studies and confirmed in five dogs during post mortem examination. Five dogs were euthanased two to seven months after surgery. Six dogs survived at least one year, two of these dogs remain alive at 17 and 27 months after surgery. It is concluded that partial cystectomy may provide local control of bladder neoplasia.     

Effect of prostaglandin E2 on rib fracture healing in beagles: histomorphometric study on periosteum adjacent to the fracture site

A histomorphometric study was done on healing defects in the ribs of Beagles. A transverse fracture was made in the left 9th and 10th ribs. Beagles were given either ethanol vehicle (n = 6) or prostaglandin (PG) E2 orally (n = 5) for the 30-day period after surgical manipulation to time of necropsy. Double fluorescent labels to measure bone matrix mineralization were given with each of 2 fluorochrome markers--calcein before dogs were surgically manipulated and oxytetracycline hydrochloride before they were euthanatized. The objectives were to determine the effects of fracture on regional remodeling in the periosteum, the effects of PGE2 on the regional remodeling changes in the periosteum induced by the fracture, and the systemic effect of PGE2 on remodeling changes of the contralateral matching sites. The fracture in the nontreated dogs (ethanol only) stimulated remodeling activity in the periosteum with increased resorption (P less than 0.01). However, after surgical manipulation (necropsy) was done, the extent of mineralization on the bone surface was decreased and was decreased more on the nonfractured ribs (right side) than on the fractured (healing) ribs (left side) (P less than 0.05). In the treated dogs, the administration of PGE2 increased the extent of mineralization on the bone surface on the healing ribs. However, as in the nontreated dogs, the administration of PGE2 did not alter the decreasing pattern of mineralization when comparing the bone surfaces at necropsy with the bone surfaces before surgical manipulation was done.(ABSTRACT TRUNCATED AT 250 WORDS)     

Partial Ulnar Osteotomy With Free Autogenous Fat Grafting for Treatment of Radius Curvus in the Dog

The efficacy of free autogenous fat grafts in inhibiting healing of partial ulnar ostectomies was investigated. Fat grafts did impede or prevent bone union in the treated ulnar ostectomies. Protection from forced weight bearing on the operated limb by splinting minimized varus deformity of the radius and ulna, and enhanced the survival of the fat graft and the formation of an ulnar nonunion. The procedure was then applied to treatment of radius curvus resulting from surgically induced premature distal ulnar physeal closure. Partial ulnar ostectomy with free autogenous fat grafting released the ulnar restraint on radial growth and allowed partial correction of the degree of radial curve associated with premature distal ulnar physeal closure.     

The Radiographic and Histologic Appearance of Controlled Surgical Manipulation of the Equine Periosteum

This study documented the normal histologic features of the equine metacarpal and metatarsal periosteum and characterized its osteogenic response to surgical manipulation. Two periosteal flaps were elevated from the dorsomedial matacarpal and metatarsal diaphysis in each of three limbs of four yearling and four adult lightbreed horses. The superficial metacarpal cortex under the flap was resected with a bone chisel in one-half of the horses and was undisturbed in the remainder. One periosteal flap in each limb was excised and the other flap was replaced and secured by sutures. All limbs in the horses were radiographed at regular intervals postoperatively. Horses were killed either 30 or 120 days after surgery. Periosteal bone production occurred only at treatment sites of young horses treated by periosteal flap replacement and was limited to approximately 50% of these sites, as determined by radiography and microradiography. Cortical abrasion resulted in an increased incidence of bone production in the periosteum adjacent to the flap perimeter. The histologic features of the periosteum were similar to those reported in other species; young horses had active osteogenesis referable to appositional growth and adults had an inactive periosteum. Histologically, osteogenesis induced by surgery resembled accentuated appositional growth in both yearlings and adults. In the horse, the cambial (osteogenic) layer is included in sharply elevated periosteal flaps. It should be removed in surgical procedures where bone production is to be avoided, and preserved where osteogenesis is desired.     

Giant cell tumor of the accessory carpal bone in a dog

A 4-year-old Springer Spaniel was referred because of a 6-week history of progressive left forelimb lameness. A marked pain response was elicited by palpation over the left accessory carpal bone. Radiography revealed a lytic, markedly expansile lesion of the accessory carpal bone. The bone was excised, and pancarpal arthrodesis was performed. Histologic examination of the excised bone revealed giant cell tumor. At 14 months after surgery, the dog was using the limb normally. Radiography of the carpus revealed satisfactory progression of the arthrodesis, and thoracic radiographs were negative for metastases.     

Pasteurized tumoral autograft and adjuvant chemotherapy for the treatment of canine distal radial osteosarcoma: 13 cases

OBJECTIVE: To report outcome in 13 dogs with distal radial osteosarcoma, without evidence of metastasis, treated by a combination of adjuvant chemotherapy and a pasteurized autograft limb-sparing procedure. STUDY DESIGN: Prospective clinical study. ANIMALS: Thirteen dogs with distal radial osteosarcoma. METHODS: Limb-sparing procedure was performed using an autograft from the excised tumoral segment, pasteurized at 65 degrees C for 40 minutes. Adjuvant chemotherapy (cisplatin or cisplatin and doxorubicin) was administered in all dogs. RESULTS: Mean and median survival times were 531 and 324 days, respectively (range, 180 to 1,868 days). Overall survival was 100% at 6 months, 50% at 12 months, 44% at 18 months, and 22% at 24 months. Lung metastasis occurred in 5 (38%) dogs. Observed complications were local recurrence (2 dogs, 15%), allograft infection (4 dogs, 31%), and implant failure (3 dogs, 23%). Limb function was good in 12 dogs (92%) and fair in 1 dog. CONCLUSIONS: Pasteurized bone autograft derived from the tumoral bone segment was an effective alternative to cortical bone allograft for limb sparing in canine distal radial osteosarcoma, in terms of feasibility, pattern of healing, complications, and survival. CLINICAL RELEVANCE: Use of a pasteurized bone autograft eliminates the need for a canine bone allograft bank and has the added advantage of good fit to the recipient site.     

Canine calvarial subperiosteal hematomas are fluid to soft tissue attenuating mass‐like lesions with smoothly marginated peripheral mineralization on CT

Subperiosteal hematomas are accumulations of blood between a bone and the periosteum leading to elevation of the periosteum. When ossified they have a mineralized outer rim. For this retrospective, multi‐institutional case series, medical records were searched to identify dogs that underwent CT for focal calvarial swellings noted acutely after trauma. A total of four dogs were included. Computed tomography images were reviewed for each case. The focal swellings had progressed in size during the weeks after the head trauma until the time of imaging. Findings in all cases included a fluid to soft tissue attenuating mass‐like lesion with smoothly marginated peripheral mineralization. Diagnosis was confirmed in two cases by cytology and/or histopathology. Therefore, authors recommend that subperiosteal hematoma be included in the differential diagnosis list for dogs with these clinical and CT characteristics. Based on our review of the literature, this is the first report to describe the CT features of calvarial subperiosteal hematomas in dogs.     

Surgical treatment of canine nasal aspergillosis by rhinotomy combined with enilconazole infusion and oral itraconazole

OBJECTIVES: To evaluate the effectiveness of rhinotomy and surgical debridement associated with topical administration of 2 per cent enilconazole and oral itraconazole in dogs with severe or recurrent sinonasal aspergillosis. METHODS: A standard rhinotomy was performed on seven dogs. In the initial study, the bone flap was left attached cranially and replaced at the end of the procedure. In the main study group, the bone flap was discarded. Nasal passages were debrided and irrigated with enilconazole solution for one hour. Oral itraconazole was administered to four dogs for one month postoperatively. Follow-up rhinoscopy was performed in all dogs. RESULTS: All three dogs in the initial study had recurrence of the disease and two dogs had a second surgery to remove the flap. The main study group included four dogs in which the flap was initially removed, and the two dogs from the initial study that required a second surgery. At follow-up rhinoscopy, five dogs were free of aspergillus but had bacterial or inflammatory rhinitis and one dog had a small aspergilloma but was subsequently asymptomatic. Telephone follow-up revealed that four dogs were asymptomatic, one dog had intermittent sneezing and serous nasal discharge, and one dog had intermittent epistaxis. CLINICAL SIGNIFICANCE: Rhinotomy with removal of the flap combined with one-hour infusion of 2 per cent enilconazole and oral itraconazole resulted in satisfactory outcome in dogs with severe or recurrent aspergillosis.     

Intrapelvic Urethral Anastomosis A Comparison of Three Techniques

Three intrapelvic urethral anastomosis techniques were performed on 12 mature male dogs to compare the degree of stricture. The intrapelvic urethra was transected 1 cm caudal to the prostate, and anastomosis was performed using either suturing of the urethra over an indwelling catheter, suturing of the urethra without an indwelling catheter, or apposition of the urethra without sutures over an indwelling catheter. Postoperatively, the dogs were evaluated using clinical urination patterns, biochemical tests, radiography, and pathology. Three of four suture-catheter dogs and one of four catheter-only dogs had normal urinary patterns. Stricture (25-84%) with urethral dilation or fistulas tracts was visible on retrograde, positive contrast urethrograms of 3 of 12 intact dogs 20 weeks after surgery, and on all 12 excised lower urinary tracts. Suture-catheter dogs subjectively had the least amount of stricture. All eight dogs (1 suture-catheter dog, 4 suture-only dogs, and 3 catheter-only dogs) with severe stricture (greater than 60% lumen diameter reduction) had histopathologic signs of chronic, inflammatory urinary tract disease, including four with chronic, ascending lymphocytic pyelonephritis. Hydroureter and hydronephrosis developed in two catheter-only dogs. Complete urethral transection resulted in some degree of stricture, regardless of technique used for anastomosis. Urethral anastomosis over an indwelling catheter appeared to result in a lesser degree of stricture and clinical and histopathologic derangement.     

Healing of Canine Autogenous Cancellous Bone Graft Donor Sites

Autogenous cancellous bone was procured from the proximal ends of one humerus and the contralateral tibia of eight adult mixed-breed dogs. Greater weights of bone were consistently harvested from the humerus than from the tibia. Restoration of cancellous bone was more rapid and complete in the humerus than in the tibia. The tibia harvest site filled primarily with fibrous tissue rather than with cancellous bone.     

Radiographic, Densitometric, and Biomechanical Effects of Recombinant Canine Somatotropin in an Unstable Ostectomy Gap Model of Bone Healing in Dogs

Objective —To determine the effect of recombinant canine somatotropin (STH) on radiographic, densitometric, and biomechanical aspects of bone healing using an unstable ostectomy gap model.
Study Design —After an ostectomy of the midshaft radius, bone healing was evaluated over an 8–week period in control dogs (n = 4) and dogs receiving recombinant canine STH (n = 4).
Animals or Sample Population—Eight sexually intact female Beagle dogs, 4 to 5 years old. Methods—Bone healing was evaluated by qualitative and quantitative evaluation of serial radiographs every 2 weeks. Terminal dual-energy x-ray absorptiometry and three-point bending biomechanical testing were also performed.
Results —Dogs receiving STH had more advanced radiographic healing of ostectomy sites. Bone area, bone mineral content, and bone density were two to five times greater at the ostectomy sites of treated dogs. Ultimate load at failure and stiffness were three and five times greater in dogs receiving STH.
Conclusions —Using the ostectomy gap model, recombinant canine STH enhanced the radiographic, densitometric, and biomechanical aspects of bone healing in dogs. Clinical Relevance—Dogs at risk for delayed healing of fractures may benefit from treatment with recombinant canine STH.     

Evaluation of full cortical allografts in 25 dogs

Twenty-five dogs received 26 cortical allografts from Apr 9, 1976 through Jan 31, 1982. Cortical allografts were used to reconstruct fractures of the femur, humerus, tibia, radius, and ulna. These grafts were used to replace comminuted fragments; to lengthen bones; to correct malunions, delayed unions, and nonunions; and in one case, to replace bone lost to sequestrum formation in an infected fracture site. All fractures were stabilized by use of standard ASIF techniques and dynamic compression plates. Frozen bone allografts were used in all cases. These were harvested aseptically and stored in a household freezer for 3 days to one year before use. Clinically normal function was achieved in 96% of the dogs.     

Resurfacing Canine Femoral Trochleoplasties with Free Autogenous Periosteal Grafts

Femoral trochleoplasties resurfaced with autogenous free periosteal grafts in six dogs were compared to femoral trochleoplasties performed without grafts in six dogs. The grafts produced cartilage as early as 4 weeks after surgery; however, it was fibrocartilage rather than normal hyaline articular cartilage. The trochleoplasties not resurfaced with periosteum also healed with fibrocartilage but not until 40 weeks postoperatively. The grafted stifles had less patellar cartilage damage when compared to trochleoplasties left to heal without resurfacing.     

Ipsilateral vascularised ulnar transposition autograft for limb-sparing surgery of the distal radius in 2 dogs with osteosarcoma

Canine osteosarcoma is the most commonly diagnosed primary bone tumour in the dog, affecting mainly large and giant breed dogs with the predilection site being the metaphysis of long bones, specifically the distal radius, proximal humerus, distal femur and proximal tibia and fibula. Treatment options are either palliative or curative intent therapy, the latter limb amputation or limb-sparing surgery together with chemotherapy. This article describes the use of an ipsilateral vascularised ulnar transposition autograft as well as chemotherapy in 2 dogs with osteosarcoma of the distal radius. Both dogs showed minimal complications with the technique and both survived over 381 days following the surgery. Complications seen were loosening of the screws and osteomyelitis. The procedure was well tolerated with excellent limb use. This technique is indicated for use in cases with small tumour size that have not broken through the bone cortex.     

COMPARISON OF DOPPLER-DERIVED AORTIC VELOCITIES OBTAINED FROM VARIOUS TRANSDUCER SITES IN HEALTHY DOGS AND CATS

In normal dogs and dogs with subaortic stenosis, it is known that the subcostal transducer site provides higher left ventricular ejection velocities than does the left apical site. We hypothesized that aortic flow velocities could also be obtained from the right parasternal long-axis view, optimized for the placement of the Doppler cursor as parallel as possible into the aortic root. In 15 healthy dogs and 13 healthy cats, high-pulsed repetition frequency Doppler flow velocity measurements in the proximal aorta were performed using two-dimensional echocardiographic guidance. The mean [ +/- standard error of the mean (SEM)] peak aortic flow velocities in healthy dogs were as follows: subcostal site 1.46 +/- 0.05 m/s; apical site 1.12 +/- 0.06 m/s; right parasternal long-axis site 1.09 +/- 0.05 m/s. In healthy cats, the following peak aortic flow velocities were observed: apical site 0.87 +/- 0.03m/s; right parasternal long-axis site 0.87 +/- 0.03 m/s. Aortic flow velocities obtained from the subcostal site were significantly higher in healthy dogs than those obtained from the left apical and right parasternal long-axis site (P< 0.001). There was no statistical difference between the peak aortic flow velocities obtained from right parasternal long-axis and left apical transducer position in all groups. We conclude therefore that right parasternal long-axis and left apical-derived aortic flow velocities are similar and may be used interchangeably in healthy dogs and cats.     

Treatment of degloving injuries with autogenous full thickness mesh scrotal free grafts

In this report, we evaluated the effectiveness of scrotal tissue as an autogenous free skin graft to treat cutaneous degloving injuries of the distal limb in dogs. Surgery was performed on two male intact dogs with distal extremity degloving wounds. Dog #1 had a tarsal degloving wound with exposure of the distal tibial and tarsal bones. Dog #2 had a degloving injury over the metacarpals. Wounds were treated with daily wet-to-dry bandages in order to develop a healthy bed of granulation tissue at the graft recipient site. Scrotal ablation castration was performed once the recipient site had been prepared. Subcutaneous and adipose tissue were excised from the scrotal graft and mesh slits were created. The graft was applied to the recipient site with monofilament absorbable simple interrupted sutures. Bandaging was performed postoperatively, and bandage changes occurred four, seven, nine and 11 days postoperatively. Follow-up was performed at 30 days. In dog #1, the tarsal degloving injury graft had first intention healing with 100% graft take on day 11. In dog #2, the metacarpal degloving injury graft had 90% graft take on day nine, with second intention healing adjacent to the fifth digit pad. The scrotum is often discarded at the time of scrotal ablation castration. Distal extremity wounds can be successfully treated with free skin grafts. In male dogs, the scrotum is a viable option as a full thickness mesh free graft for distal extremity reconstructive surgery.