The Anatomic Basis of a Free Vascularized Bone Graft Based on the Canine Distal Ulna

The anatomy of the canine distal ulna was evaluated to determine its potential as a free vascularized bone graft. Twelve cadavers were studied by gross dissection and nonselective and selective angiography. The caudal interosseous artery consistently served as a source artery to the distal ulnar periosteal vasculature in all dogs. The diameters of the caudal interosseous artery and venae comitantes were large enough to permit microvascular anastomoses. Nonselective perfusions of the brachial artery demonstrated large barium-filled vessels within soft tissues surrounding the ulna with anastomotic connections between medullary and periosteal vasculature. Grafts selectively perfused through the caudal interosseous artery (periosteal circulation only) had barium-filled vessels within the muscular cuff, periosteum, cortical bone, and medullary canal of the ulna. A surgical approach to remove the distal ulna along with an intact musculoperiosteal cuff and its associated vasculature is described.     

Evaluation of Canine Cortical Bone Graft Remodeling

A stable cortical bone fracture model was developed to evaluate the remodeling rate of cortical bone grafts. Samples of cortical bone were harvested with a trephine and press fit into predrilled holes in the femoral diaphyses of four live dogs. The percentages of new bone, unremodeled graft bone, porosity, forming bone surface area, and resorbing bone surface area were determined morphometrically and compared in cortical autografts, cortical allografts sterilized with 84% ethylene oxide (EO), and allografts sterilized with 12% EO. The host-graft interfaces healed without formation of fibrous tissue or cartilage, indicating a stable fracture surface. The amount of new bone formed in cortical autografts and allografts sterilized with 84% EO was significantly greater than the amount of new bone in allografts sterilized with 12% EO. There was no significant difference between the amounts of new bone formed in the allografts sterilized with 84% EO and the cortical autografts. No significant differences were detected in percentages of porosity or bone surface areas.     

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.     

A Developmental Model for Free Vascularized Bone Transfers in the Dog

An autogenous free vascular bone transfer using a segment of ulna along with its periosteum and vascular pedicle was developed. The vascular pedicle, based on the common interosseous artery and vein, emerged where muscular branches from the cranial interosseous artery enter the extensor carpi ulnaris and lateral digital extensor muscles. Four autogenous heterotopic (ulna to tibia) vascular transfers by microvascular anastomosis and two avascular transfers were performed to compare the osteogenic potential and viability of free revascularized grafts with avascular bone grafts. Successful microvascular anastomosis was demonstrated in three of the four vascular transfers by early bone scanning using technetium-labeled polyphosphate. Radiographically, there was more periosteal new bone and callus formation in the successfully revascularized bone transfers than in the failed vascular transfer and the avascular controls. Histologically, viable bone with an intact medullary and periosteal vascular supply was recognized in the grafts successfully revascularized by microvascular anastomosis.     

Asynchronous Growth of the Canine Radius and Ulna: Surgical Correction following Experimental Premature Closure of the Distal Radial Physis

Marked lameness and elbow incongruity occurred in seven 21-week-old dogs following experimental premature closure of the distal radial physis at 10 weeks of age. Midradial transverse osteotomies and bone plate stabilization performed on five dogs resulted in marked reduction of elbow incongruity and forelimb lameness. Two dogs had no surgery and served as controls for the surgical procedure. At 50 weeks of age the proximal radial articular surface was displaced 5.3 mm farther from the coronoid process in control dogs as compared to dogs having transverse radial osteotomy. Markedly worse clinical, radiographic, and pathologic changes in the control group demonstrated the importance of reestablishing and preserving elbow congruity when treating asynchronous growth of the canine forelimb caused by premature closure of the distal radial physis. The technique described is recommended as one method to treat premature distal radial physeal closure clinically.     

普通T形骨板治疗玩具犬桡尺骨远端骨折的手术效果

旨在评估普通T形骨板内固定治疗玩具犬桡尺骨远端骨折的临床效果及并发症。回顾了在中国农业大学动物医院采用开放式复位和普通T形骨板内固定治疗桡尺骨远端骨折的玩具犬的病历记录,并对这些病例进行回访。入选病例满足：体重不超过7 kg;骨折位置位于前臂远端(远端骨段与桡骨长度比值<0.25);回访时间>12个月;病例信息记录完整。结果表明：共纳入29只犬的29例桡尺骨远端骨折,26例(89.7%)术后无跛行,3例(10.3%)术后勉强可见跛行。未发生严重并发症,轻微并发症的发生率是20.7%(n=6)。普通T形骨板内固定能有效治疗玩具犬桡尺骨远端骨折,临床效果良好,无严重并发症。     

Use of a Vascular Skeletal Muscle Graft for Canine Esophageal Reconstruction

A technique for reconstruction of the thoracic esophagus was evaluated in 13 dogs. A 9 x 10 cm section of transversus abdominis muscle was harvested, fashioned into a tubular graft, and vascularized via the greater omentum. The vascularized tube was advanced into the caudal thorax through the diaphragm at a second surgery 20 to 44 days after harvesting the section of the transversus abdominis muscle. A 5 cm section of caudal thoracic esophagus was replaced with the vascular tubular graft. One dog died because of incarceration of the intestine within the tube and two dogs were euthanized because of infected tubes. One dog died due to an anesthetic complication, one dog had a diaphragmatic hernia and died, and one dog died from pyothorax. Leakage of luminal contents at the anastomoses did not occur in any dog. Seven dogs survived both surgeries but showed deglutitory difficulty 6 days postoperatively due to the grafted esophageal segments becoming severely strictured in each case. Angiography demonstrated vascularization of the full thickness of the graft in each of the seven dogs. An unacceptably high incidence of infection and stricture formation made this technique unsuitable for clinical use.     

Orthotopic Osteochondral Transplantation of the Canine Proximal Femur

An 18-week study was conducted to evaluate orthotopic osteochondral transplantation of the proximal femur in the dog. Eighteen dogs were divided into 3 groups of 6 each. The first group received autografts, the second received fresh allografts, and the third received grafts that had been frozen in a bone bank for 24–28 days. The grafts were fixed in position using dynamic compression plates. The grafted limbs were maintained in a sling and thus were nonfunctional and non-weight bearing throughout the 18-week study. Postoperatively the dogs were given oral tetracycline to assess osteo- cyte viability. The dogs were radiographed at 2–week intervals and 1 dog in each group was euthanatized every 3 weeks. The femurs were examined using standard histopathologic and fluorescent labeling techniques. All femoral heads were luxated by the 2nd postoperative week. The bones of all the femoral heads underwent avascular necrosis and degenerative changes were present in the transplanted cartilage by the 6th postoperative week. During the first 18 weeks following transplantation there was little radiographic and histologic difference among the 3 types of grafts regarding the nature and rate of bone healing. Based on the data obtained from techniques utilized in this study, the femoral head, neck, and articular cartilage did not survive, while the femoral diaphysis did survive the transplantation process. Different techniques may alter to some degree the results obtained.     

Repair of a Mandibular Defect With a Free Vascularized Coccygeal Vertebra Transfer in a Dog

Bilateral mandibular defects in a male mongrel dog were repaired. On the left side, a free vascularized coccygeal bone graft that included the median caudal artery and caudal vein was used to correct the defect. On the right side, the defect was bridged with a bone plate and screws. For further immobilization, the muzzle was temporarily taped for 3 weeks and a pharyngostomy tube was used for nutritional support. The dog was able to eat dry commercial food satisfactorily within 2 months of surgery despite mild malocclusion. Radiographs taken 2 months and 18 months postoperatively showed bony union with graft hypertrophy in the left mandible, whereas the right mandibular defect showed protracted nonunion. The results indicate that vascularized coccygeal vertebra transfer provides an alternative for the management of canine mandibular defects.     

小型犬尺桡骨,股骨远端骨折的钢板植入及取出手术

本文对小型犬尺桡骨和股骨远端骨折实施了钢板植入和愈合后钢板的取出手术。由于小型犬骨骼细,找不到合适的钢板。我们利用现有的材料根据骨折的具体情况,进行了钢板植入手术的尝试均取得了成功。     

Use of a Cortico-Cancellous Bone Graft in the Repair of a Cleft Palate in a Dog

We report the successful use of a cortico-cancellous bone graft to repair a cleft of the secondary palate in a 6-month-old Akita dog. The cleft extended from the incisal papilla to the posterior border of the soft palate. It was 10 mm wide in the hard palate and 16 mm in the soft palate. The cleft was repaired using the "push-back" method with single-pedicled mucoperiosteal flaps to close the cleft in the soft tissues, and a free bone graft from the tibia (cortex with cancellous bone attached) to fill the defect in the hard palate. Two and one-half years after the operation the graft was indistinguishable from surrounding bone on radiographs. Maxillary growth appeared to have progressed normally, resulting in normal occlusion.     

Cancellous Bone Graft Collection from the Tibia in Dogs

Autologous cancellous bone was collected from the metaphysis of the proximal end of the tibia in 30 medium and large dogs. Access to the metaphyseal cancellous bone was gained by making a medial opening in the cortex with a 5.6, 7.9, or 10 mm bone trephine. Sufficient bone was obtained from this site for grafting in each case. Four dogs had bilateral carpal arthrodesis that necessitated graft collection from both tibias. Complications arising from graft collection included wound disruption 5 days postoperatively (3/34 graft sites) and incomplete fracture of the tibial cortex created during the surgical procedure (1/34 graft sites). Collection of autologous cancellous bone from this sita in mature, medium and large dogs was found to be a safe procedure with a low incidence of donor site morbidity.     

Vascularized Patellar Tendon Graft Technique for Cranial Cruciate Ligament Substitution in the Dog—Vascular Evaluation

A method of repair of the dog's cranial cruciate ligament, using a vascular patellar tendon* graft (VPT), is described. The vascular anatomy of the graft was evaluated in an experimental study in 18 dogs. The blood supply to the VPTs was evaluated at various intervals from 0 to 16 weeks and was found to be preserved in all but two of the specimens examined. It was concluded that the VPT technique could maintain vascularity to the graft from the onset.     

Free Microvascular Transplantation of the Trapezius Musculocutaneous Flap in Dogs

A musculocutaneous flap based on the prescapular branch of the superficial cervical artery and including the cervical part of the trapezius muscle and overlying skin was transplanted over a defect created on the medial side of the contralateral tibia in four dogs by using microvascular technique. The donor and recipient sites in three dogs were examined clinically for 21 days, after which they were examined angiographically and histologically. All dogs were free of lameness by hour 48. Seromas formed at the donor site between days 7 and 15. One vascular pedicle was traumatized at hour 40, and the dog was euthanatized. Three flaps survived with minimal necrosis. Edema of the flaps was severe from days 5 to 11. Angiograms showed complete perfusion of the flaps, and survival was confirmed histologically. Esthetic appearance and function were good in one dog at month 7.     

犬污染骨异位寄养再回植的影像学评估

[目的]探讨犬游离长段桡骨通过寄养在血运丰富的隐静脉旁使其血管化来修复开放性骨折造成的骨缺损的可行性。[方法]选取12只成年健康犬随机分为实验组与对照组,2组分别截取右侧前肢桡骨中段约15 mm的桡骨骨段。模拟车祸环境,将截取的长段桡骨放置于外界泥土中1 h,取回的骨块用大量生理盐水冲洗,并放置在10%聚维酮碘中浸泡5 min,之后使用生理盐水冲洗1 min,沥干备用。实验组将其包埋在血管丰富的隐静脉处,对照组放置于-80℃低温无菌保存。8周后取出骨块,植回原位修复犬桡骨骨缺损。回植后第6、12周观察桡骨的大体形态。第4、8、12周通过X射线观察修复效果,使用Lane-Sandhu X线评分标准进行评分。[结果]在同一时间段内,实验组桡骨骨缺损修复的效果均好于对照组。[结论]通过寄养血管化的长段骨和低温保存长段骨均可修复犬桡骨骨缺损,与-80℃保存的骨块相比血管化的长段骨具有愈合时间短、骨吸收少的优点。