Bone Transfer Research Articles

Application of High-Tech Three-Dimensional Imaging and Computer-Generated Models in Complex Facial Reconstructions with Vascularized Bone Grafts

We present a series of six patients with eight flaps in whom computer-generated models were used for fabrication of vascularized bone grafts in complex facial restorations. Preoperative CT data, digitalized on tape, were converted by the CEMAX (Santa Clara, Calif.) 1500 Integrated Hardware and Software System to a three-dimensional visualization of the bone and soft-tissue deficiencies. These data were transmitted by direct computer link to a CNC milling machine that produced full-size slices "stacked" into a three-dimensional template. The acrylic replica aided selection of appropriate donor sites and intraoperative "carving" of bone transfers. Reconstructions included three zygomas, two maxillae, two mandibles, and one frontal bone. Donor sites were iliac crest, scapula, and outer calvarium. Four were free flaps and four island pedicle flaps. All healed without infection. Bone resorption was less than 10 percent. One flap was lost to thrombosis. Other complications included a transient facial palsy in one patient and temporary radial palsy from shoulder traction in another. Computer-generated templates for vascularized grafts are expensive and thus are not indicated or necessary in every patient. The advantages, however, are several. Custom models facilitate preoperative planning, with less guesswork of size, contour, and orientation of the graft, which is especially desirable with vascularized grafts, since the position of the pedicle is critical. Anesthesia time is decreased. Grafts can be fitted exactly, without reshaping and "nibbling." Nuances of depth and tapering are directly carved into the bone. By merging high-tech imaging and microsurgery, the best chance of optimal results can be achieved.

Alpha-Adrenergic Receptor Responsiveness in Vascular Smooth Muscle of Canine Bone

In an ex vivo canine tibial preparation, an alpha-1-adrenergic antagonist (prazosin, 212 ng.ml-1.minute-1) markedly attenuated the effect of high intraluminal doses (greater than 0.5 mg) of norepinephrine but was less effective at lower doses. An alpha-2-adrenergic antagonist (rauwolscine, 198 ng/ml/minute) was more effective than prazosin in blocking the vascular smooth muscle contraction evoked by low doses of norepinephrine (greater than 0.125 mg). Cirazoline, an alpha-1-adrenergic agonist, had a potent contractile effect on smooth muscle at high concentrations (5 x 10(-6) M), whereas the alpha-2-adrenergic agonist UK14304 was more effective at low concentrations (1 x 10(-7) M). Thus, in the vascular smooth muscle of canine tibia there is a mixed population of postjunctional alpha-1 and alpha-2-adrenergic receptors that exhibits a dose-dependent responsiveness. Adrenergic receptor mechanisms may contribute to alterations in bone blood flow. This may be relevant to impaired reperfusion after microvascular bone transfer. Furthermore, adrenergic receptor mechanisms may help explain variations in bone blood flow related to systemic, regional humoral, or metabolic factors.

Mandibular reconstruction: Experience with the free vascularized fibula transfer

Mandibular resection, following surgery for tumor or osteoradionecrosis, leaves a patient with a swallowing, speech, and cosmetic disability. Repair of the oromandibular defect is difficult and various prostheses and grafts have been used and reported. The most popular form of mandibular reconstruction is the use of the free, vascularized bone transfer. We report our experience with the free vascularized fibula bone transfer in eight patients.

Histological evaluation of free revascularized iliac crest bone after transplantation for mandibular reconstruction.

Differing views on the nutritional status of revascularized bone in animal studies and in human transfer have been expressed. Normal viability is reported as well as single cell necrosis and devitalized areas and, finally, necrosis of the complete graft. From 19 patients with revascularized bone transfer into injured recipient tissues, we obtained 32 drill biopsies out of the centre of the graft and near the mandibular stump during the removal of the osteosynthesis plates. The histological preparations were examined for bone viability. In 58% of all patients, there occurred partial necroses in the grafted bone and in 26% single cell necroses; 16% of the transplants maintained normal viability. The areas with disturbed nutrition were found more frequently in peripheral areas than in central regions of the graft (p < 0.05, chi 2 test). The overall graft failure rate was 6.8%. The results of this clinical study are discussed with particular reference to the technical procedure, the recipient tissue quality, and the design of the graft. The indication for using revascularized bone transfer in difficult local conditions of the recipient tissues has been confirmed. The viability of the grafts cannot always be maintained entirely. The particular risk to the viability of the graft in the peripheral regions requires careful technical procedures.

Vascularized bone transfer.

We evaluated the results of reconstruction of a skeletal defect with use of a vascularized bone graft from the iliac crest or fibula in 160 patients who had been managed consecutively between 1979 and 1989. The indications for the procedure were a skeletal defect including non-union, resulting from resection of a tumor; traumatic bone loss; osteomyelitis; or a congenital anomaly. The average duration of follow-up was forty-two months (range, twelve to 112 months). For the entire series, the rate of union after the primary procedure was 61 per cent and the over-all rate at the latest follow-up examination (including the patients who had a secondary procedure) was 81 per cent. In a subgroup of seventy-six patients who had union after the primary procedure and did not have additional treatment, the average interval until union was six months and the average interval until full activity was sixteen months. The results were more favorable for the patients who had had reconstruction for resection of a tumor (of sixty-nine patients, fifty-six had union), for a congenital anomaly (of six patients, five had union), or for a non-union without infection (of twenty-five patients, twenty-three had union). The results were less satisfactory for patients who had had the reconstruction for bone loss due to osteomyelitis (of sixty patients, forty-six had union). Our data suggest that vascularized bone transfer for the reconstruction of large skeletal defects is a valuable procedure in appropriately selected patients.

VASCULARIZED BONE GRAFTS TO THE UPPER EXTREMITY

Massive autogenous bone grafts with an intact vascular pedicle decrease the time to bony union and immobilization required for treatment of segmental bony defects. These techniques have been shown to be effective in treatment of segmental defects of more than 6 cm after trauma or tumor resection in relatively avascular beds. Additionally, in the upper extremity, the free vascularized bone graft is in the developmental phase for employment in the reconstruction of epiphyseal arrest and congenital radial club hand. There are disadvantages to free vascularized bone transfers compared with conventional techniques. For example, a free vascularized fibular transfer requires a team skilled in microvascular technique, a long operative time (6 to 10 hours), and the sacrifice of a major vessel to the lower extremity. If the anastomosis fails, however, the free vascularized fibula will act as a conventional bone graft, thereby minimizing adverse effects. We think that by proper patient selection, appropriate evaluation and preparation of the bony defect, meticulous microvascular anastomosis, and correct fixation and immobilization of the graft a good outcome can be achieved in those patients with large bony defects that defy the use of conventional methods.

Free Microvascular Fibular Transfer for Idiopathic Femoral Head Necrosis: Long-Term Follow-Up

The authors discuss free microvascular bone transfers in general, and propose a new classification for idiopathic femoral head necrosis. They then present a technique they have been using for 11 years, with the goals of providing both mechanical support and an improved blood supply to the femoral head. This technique involves clearing the necrotic area of the femoral head, filling the area with cancellous bone taken from the greater and lesser trochanters, and transferring a fibular microvascular graft. The approach is transtrochanteric and spares the capsule. Vascular anastomosis is done with the lateral branches of the deep femoral artery, sparing the anterior circumflex artery which is important to the blood supply of the femoral head. Forty-five cases have been surgically managed over 11 years. Eighteen cases with follow-up longer than five years were analyzed, providing an 84 percent successful outcome with both very good and good results.

Vascularised bone transfer for defects and pseudarthroses of forearm bones

During a five-year period, 15 patients with defects or pseudarthroses of the forearm bones were operated on. All had previously undergone one to six conventional operations. A vascularised fibular graft was used in ten cases, a radial graft in three cases and a humeral graft in two cases. Bone graft viability and healing were assessed clinically and patients have been observed for seven months to five years. 14 patients have finished treatment: 13 were cured and only two repeat osteosyntheses were required. In one case there was resorption of the central part of the fibular graft. Primary bony union was achieved in three to six months. Care must be taken in precise pre-operative assessment of the state of the forearm arteries. We advocate wider usage of vascularised radial and humeral grafts.

Experimental transplantation of vascularized autologous and allogenic bone grafts for mandibular defects: Anatomical, immunological and surgical basis for vascularized bone transfer in the Göttingen minipig

The Göttingen minipig serves as a suitable animal model for studying microsurgically reanastomosed iliac crest grafts for reconstruction of bone defects of the mandible. Because of the vascularization pattern of the hip bones of the Göttingen minipig, the cranioventral region of the ilium is especially suitable as a donor site. The separate vascularization of this area allows the excision of a bone block with sufficient volume, mechanical strength and a reliable vascular pedicle. The high degree of immunological variability of the minipigs demonstrated by isoelectric focusing and subsequent immunoblotting of lymphocyte membrane proteins offers possibilities for allogenic transplantation models. The surgical technique of harvesting and transplantation of the bone graft is described in detail.

Microsurgical free bone transfer in the dog

Bone grafts have been used extensively for the reconstruction of skeletal injury in dogs. Cancellous and corticocancellous chip autografts are used for their osteoinductive and osteoconductive properties. Fresh, fresh-frozen, freeze-dried, and ethylene oxide-sterilized cortical allografts have been recommended for the reconstruction of segmental cortical defects. Donor sites for microsurgical bone transfer have been identified experimentally in the dog, but these remain to be used clinically. This paper reviews the anatomy and structural characteristics of donor sites for microsurgical bone transfer. Potential clinical indications for microsurgical bone transfer in the dog are described.

当科におけるＪ‐２型人工骨頭置換術の成績

We studied a group of 22 patients (7 males and 15 females) which consist of 20 cases of femoral neck fracture and 2 cases of idiopathic femoral head necrosis, treated by J-2 type prosthesis during 1984-1990. Age distribution of these cases were 45 to 92 years old (mean: 75.4 years), and were followed from 2 months to 6 years and 7 months (mean: 2 years and 6 months).Postoperative OA hip score of the Japanese Orthopaedic Association (J. O. A. Score) was 80.1 points on an average. Rsults were discussed to J. O. A. score, ability of transfer, bone atrophy, thinness or thickness of cortical bone, central migration, sinking and pathology of one death case.

Laser doppler bone probe: An experimental study in dogs

Immediate reintervention is necessary when vascular insufficiency is suspected in free bone transfers. We tested the reliability of the laser doppler bone probe in recording steady state and arterial and venous occlusion. During steady state the flux signal was not constant but fluctuated. During arterial occlusion an immediate and reproducible decrease in flux signal was seen. No evident changes were seen during venous occlusion. These results have clinical importance in monitoring free bone transfers.

Vascularized autogenous canine coccygeal bone transfer

Based on cadaver studies in dogs, the 8th, 9th, or 10th canine coccygeal vertebra with overlying skin was designed for free vascularized bone transfer. In six dogs the coccygeal osteocutaneous flap was transferred to fill a defect of the tibia, anastomosing the median caudal artery and one of the two caudal veins to the tibial vessels. The overlying skin provided a reliable monitoring system for the transferred tissue. The behavior of the vascularized coccygeal vertebrae was then evaluated with radiographic and histologic examination and compared with control vertebrae transferred without reconnection of the blood vessels. The results revealed that the canine coccygeal bone graft is a reliable vascularized osteocutaneous flap, which can be applied either in clinical veterinary surgery or in orthopedic microsurgical research.

Mandibular reconstruction with composite microvascular tissue transfer

Microvascular free tissue transfer has provided a variety of methods of restoring vascularized bone and soft tissue to difficult defects created by tumor resection and trauma. Over 7 years, 26 patients have undergone 28 free flaps for mandibular reconstruction, 15 for primary squamous cell carcinoma of the floor of the mouth or tongue, 7 for recurrent tumor, and 6 for other reasons [lymphangioma (1), infection (1), gunshot wound (1), and osteoradionecrosis (3)]. Primary reconstruction was performed in 19 cases and secondary in 9. All repairs were composite flaps including 12 scapula, 5 radial forearm, 3 fibula, 2 serratus, and 6 deep circumflex iliac artery. Mandibular defects included the symphysis alone (7), symphysis and body (5), symphysis-body-ramus condyle (2), body or ramus (13), and bilateral body (1). Fourteen patients had received prior radiotherapy to adjuvant or curative doses. Eight received postoperative radiotherapy. All patients had initially successful vascularized reconstruction by clinical examination (28) and positive radionuclide scan (22 of 22). Bony stability was achieved in 25 of 26 patients and oral continence in 24 of 26. One complete flap loss occurred at 14 days. Complications of some degree developed in 22 patients including partial skin necrosis (3), orocutaneous fistula (3), plate exposure (1), donor site infection (3), fracture of reconstruction (1), and fracture of the radius (1). Microvascular transfer of bone and soft tissue allows a reliable reconstruction--despite previous radiotherapy, infection, foreign body, or surgery--in almost every situation in which mandible and soft tissue are absent. Bony union, a healed wound, and reasonable function and appearance are likely despite early fistula, skin loss, or metal plate or bone exposure.

FEMORAL HEAD ALLOGRAFT BONE BANKING

Prior to 1986, there was no uniform protocol for the collection, storage and safe transfer of allograft bone in South Australia. A programme was instituted that resulted in the collection of 100 femoral heads, of which 46 heads were used for a variety of orthopaedic procedures in 31 patients. Wastage was high with 46 femoral heads being discarded because of infection or failure to adhere to all aspects of the protocol. The donor population was found to be a safe source of bone with no cases of unsuspected hepatitis, syphilis, human immunodeficiency virus, or malignancy being detected. There was no infection in recipients. By observing strict criteria for the acceptance of donor bone and aided by a diligent clerical service, this type of allograft can provide a way of dealing with extensive bone deficiency in a number of surgical settings.

Effects of Vascularized Bone Graft on Surrounding Necrotic Bone: An Experimental Study

Several difficult problems arise in the treatment of necrotic bone disorders such as femoral head necrosis or Kienböck's disease for which no definitive treatment as yet exists. The recent literature has recommended vascularized bone transfers as suitable for these disorders, but there have been few experimental studies done and resulting effects are still currently obscure. Using a rabbit model, the effects of vascularized bone graft on the surrounding necrotic bone were analyzed. Results suggest that the periosteal muscle cuff remains as fibrous or fatty tissue and interferes with the bony union between the graft and the host bone; the graft was found to be gradually resorbed. The main function of the procedure appears to be the provision of vessels into avascular bone.

Blood flow evaluation of vascularized bone transfers in a canine model

Blood flow in vascularized bone transfers was evaluated in a canine model. Cortical bone blood flow was determined in undisturbed control bone, vascularized heterotopic bone transfers, and nonvascularized cortical bone grafts by means of the radionuclide-labeled microsphere technique. Four animals were studied at 2 days, three at 1 week, eight at 2 weeks, four at 4 weeks, and three at 6 weeks postoperatively. In the 2-day animals, the vascularized bone transfers exhibited intermediate levels of blood flow (1.4 +/- 0.4 ml/100 g of bone/min) compared with undisturbed control bone (2.7 +/- 0.5 ml/100 g of bone/min) and conventional cortical bone grafts (0.0 +/- 0.0 ml/100 g of bone/min). At 1 week postoperatively, the differences in blood flow values of the vascularized transfers (1.7 +/- 0.7 ml/100 g of bone/min) and control bone (1.4 +/- 1.0 ml/100 g of bone/min) and of the nonvascularized grafts (0.2 +/- 0.1 ml/100 g of bone/min) and control bone (1.6 +/- 1.1 ml/100 g of bone/min) were no longer significant. At 2 weeks postoperatively, blood flow had increased in both graft groups. At 4 weeks postoperatively, the bone blood flow values in the vascularized transfers (4.8 +/- 1.4 ml/100 g of bone/min) were significantly greater than the bone blood flow in control specimens (1.6 +/- 0.5 ml/100 g of bone/min) and conventional cortical bone grafts (2.5 +/- 2.0 ml/100 g of bone/min).(ABSTRACT TRUNCATED AT 250 WORDS)

Femoral reconstruction by vascularized bone transfer

Thirty-five patients with extensive femoral defects or recalcitrant nonunions were reconstructed by microvascular bone transfer with a follow-up period exceeding 12 months. The cause of bone defect included trauma, debridement for osteomyelitis, or tumor resection, and the cause of nonunion included trauma or postirradiation osteonecrosis. Sixty-nine percent of patients healed primarily, whereas 83% of patients ultimately progressed to union following secondary surgery. One patient who initially healed later required amputation for late graft fracture with nonunion; therefore, at final follow-up, 80% of patients were fully healed. Vascularized bone transfer merits strong consideration for reconstruction of atypical and particularly difficult femoral nonunions.

Growth and Survival of Vascularized and Nonvascularized Membranous Bone

Although nonvascularized membranous bone grafts to the craniofacial skeleton demonstrate improved survival over similar grafts of endochondral origin, the comparative fate of vascularized membranous grafts is unknown. It is also unknown whether onlay membranous bone grafts in immature animals have the ability to grow. To examine these questions, a model was developed in New Zealand white rabbits in which a segment of the zygomatic arch was transferred to the subjacent mandible as either a vascularized or nonvascularized transfer. At harvest 16 weeks later, residual graft volume and bone architecture were analyzed. Results demonstrate no improved survival for vascularized membranous grafts in adult animals (n = 7), while in the immature animals (n = 6), growth of the vascularized bone transfers was documented. We conclude that in the majority of instances in craniofacial reconstruction, nonvascularized onlay membranous grafts are to be preferred. Specific instances for the use of vascularized transfers will be discussed.

Primary Placement of Osseointegrated Implants in Microvascular Mandibular Reconstruction

The goal of mandibular reconstruction is to rehabilitate the patient by restoring occlusal relationships, lower facial contour, oral continence, and a denture-bearing surface. One of the major advantages of the use of vascularized bone over all other methods of mandibular reconstruction is its ability to achieve dental rehabilitation rapidly. The use of osseointegrated dental implants is a valuable adjunct in oral rehabilitation. It provides the most rigid form of stabilization to withstand the forces of mastication. In situations in which soft tissue reconstruction or the height of the alveolar ridge is not sufficient for a tissue-borne denture, implants offer the most suitable alternative. Mandibular reconstruction with free tissue transfer techniques is ideally suited for the placement of implants. These can be inserted at the time of mandibular reconstruction. Four months after surgery, when the integration process has occurred, the implants are unroofed, loaded, and ready for prosthetic placement. We will present several representative patients who underwent mandibular reconstruction with microvascular free bone transfer who have been successfully rehabilitated by osseointegrated implants. The process of osseointegration, different types of dental implants, and issues regarding radiation and implants are discussed. This is the first report of dental rehabilitation by primary placement of dental implants in patients undergoing microvascular mandibular reconstruction.