A comparison of vascularized and nonvascularized bone transfer in rabbits: a roentgenographic, scintigraphic, and histologic evaluation

Value of a skin island flap as a postoperative predictor of vascularized fibula graft viability in extensive diaphyseal bone defect reconstruction

PURPOSE

To evaluate the feasibility and reliability of free vascularized fibular graft with skin island flap for reconstruction of large diaphyseal bone defect.

METHOD

The clinical results of vascularized fibular graft and experiences related to the importance and reliability of a monitoring island flap for the reconstruction of various long-bone defects were reviewed in 87 patients.

RESULTS

Bony reconstruction was achieved in 82 of the 87 patients. Arterial thrombosis of anastomosed vessel in two patients and venous congestion of monitoring flap in nine patients occurred in the early postoperative periods. All of them were managed by immediate thrombectomy and reanastomosis, alternatively the thrombotic veins were replaced by new veins to anastomose with the superficial veins in five patients. Partial flap necrosis was noted in six patients, but additional surgical intervention was not required. The vascularized fibula survived and bony fusion was achieved in all patients. Postoperative stress fractures of the fibula graft occurred in 19 (21.8%) patients (once in seven patients, twice in five patients, three or more times in seven) as the mechanical stress to the graft increased. Included fracture on the tibia in 12 patients, humerus in one and femur in six. Treatments included casting in 11 patients, percutaneous pinning in one case, and adjustment of external fixator in seven patients. Bony union was finally achieved an average of 9.6 months after fracture.

CONCLUSIONS

Correct alignment between the recipient bone and the external fixator is a prerequisite to preventing graft fracture. Vascularized fibula transfer is a valuable procedure for long-bone defects, and a skin island-monitoring flap is a simple, extremely useful, and reliable method for assessing the vascular status of vascularized fibula.

LEVEL OF EVIDENCE

Level IV. Retrospective study.

Vascular anatomy of the palmar surfaces of the distal radius and ulna: its relevance to pedicled bone grafts at the distal palmar forearm

The potential for harvesting vascularized bone grafts from the palmar surface of the distal radius has been studied in 40 arms of fresh cadavers which had previously been injected with coloured latex solution. It was found that vascularized grafts can be pedicled on the radial part of the palmar carpal arterial arch. If a longer pedicle is required, the bone graft can be pedicled on the anterior branch of the anterior interosseous artery with retrograde flow occurring from the palmar carpal arch.

Free vascularized osteocutaneous fibular graft to the tibia

We reviewed the clinical results of reconstruction performed for extensive tibial bone and soft tissue defect with a free vascularized osteocutaneous fibular graft in 46 patients (43 male and 3 female). The mean duration of follow-up was 30 months (range 13-76 months). The mean age at the time of reconstruction was 41 years (range 15-66 years). In the 46 consecutive procedures of free vascularized osteocutaneous fibular grafts, bony union was achieved in 43 grafted fibulae at an average of 3.75 months after operation. There were two delayed unions and one non-union. Forty-four cutaneous flaps survived, and two cutaneous flaps failed due to deep infection and venous insufficiency. One necrotized cutaneous flap was replaced with a latissimus dorsi free flap and the other with a soleus muscle rotational flap without replacing the grafted fibulae; unions were obtained without significance complications. All grafted fibulae hypertrophied during the follow-up periods. The most common complication was fracture of the grafted fibulae in 15 patients, and it occurred at an average of 9.7 months after the reconstruction. The fractured fibulae were treated with long leg above-the-knee cast immobilization or internal fixation with conventional cancellous bone graft. Free vascularized osteocutaneous fibular graft is a good treatment modality for the reconstruction of extensive bone and soft tissue defect in the leg. Fracture of the grafted fibula, one of the most common complications after this operation, can easily be treated with cast immobilization or internal fixation with conventional cancellous bone graft.

Infection of vascularized fibular grafts

Between June 1978 and July 1991, 64 limb reconstructions were done using vascularized fibular grafts. Of these, 10 became infected. Five grafts were proven viable, whereas the other 5 were proven nonviable based on the survival of the skin in the composite osteocutaneous graft and from bone scans, angiograms, and biopsies. A distinct difference in the radiologic manifestation and clinical course of the infection was noted between the viable grafts and nonviable grafts. The viable grafts showed radiologic changes of osteomyelitis that were localized, and the graft incorporated, healed with antibiotics, and exhibited graft hypertrophy. In the nonviable grafts, the radiologic changes were extensive, evidence that resorption of the grafts had resulted. This suggests that, because of the poor prognosis associated with infection of the nonviable vascularized fibular grafts, the infected grafts should be removed early to minimize the morbidity and to shorten the protracted course associated with infection. With the infected viable grafts, efforts at salvaging the graft with multiple debridements and systemic antibiotics were rewarding.

Evaluation of the incorporation of bone grafts used in maxillofacial surgery with [18F]fluoride ion and dynamic positron emission tomography

This study investigates the incorporation of bone grafts used in maxillofacial surgery by means of [18F]fluoride ion and positron emission tomography (PET). It considers patients who received pedicle grafts for mandibular reconstruction or onlay grafts for alveolar ridge augmentation. Dynamic PET images and arterialized venous blood samples were obtained within a 1-h period after i.v. injection of [18F]fluoride. Assuming a three-compartment model and applying multilinear least squares fitting, bone blood flow (K1) and fluoride influx (Kmlf) were determined. Additionally Patlak plot analysis was used to calculate fluoride influx (Kpat). In cervical vertebral bodies as the reference region, mean values for flow of K1 = 0.1162 +/- 0.0396 ml/min/ml and influx of Kmlf = 0.0508 +/- 0.0193 and Kpat = 0.0385 +/- 0.0102 ml/min/ml were found. Essentially these figures are comparable with physiological values in animal and man reported in the literature. Early after surgery a significant increase in flow and influx compared to vertebral bodies was observed in the regions of osteosyntheses between grafts used for reconstruction and recipient bone (K1 = 0.2181, Kmlf = 0.1000 and Kpat = 0.0666 ml/min/ml) and in onlay grafts (K1 = 0.2842, Kmlf = 0.1637 and Kpat = 0.0827 ml/min/ml). At the same time pedicle grafts showed a significant increase in flow but not in influx (K1 = 0.2042, Kmlf = 0.0774 and Kpat = 0.0529 ml/min/ml). Furthermore Kpat was significantly lower in pedicle grafts than in onlay grafts. In follow-up studies a significant decrease in flow occurred in pedicle grafts and the regions of osteosyntheses. Moreover the latter showed a significant decrease in Kmlf as well. It is concluded that [18F(-)] PET depicted increased blood flow and osteoblastic activity in onlay grafts and regions of osteosyntheses, indicating bone repair in the graft and adjacent host bone early after surgery. For the regions of osteosyntheses the decrease in both parameters corresponded to uncomplicated healing. The lack of increased influx, although flow was increased in pedicle grafts, most likely indicates that some necrosis occurred in these grafts despite patency of anastomoses. It may be concluded that [18F(-)] PET provides further insight into the biology of graft incorporation.

Bone scintigraphy in the evaluation of bone grafts used for mandibular reconstruction

Bone scintigraphy was applied in the follow-up of 24 patients who received bone grafts for reconstruction of the mandible after partial resection. Semiquantitative assessment of the grafts was done with a six-grade scoring system, based on comparison of tracer uptake in the graft and in the calvarium (as an internal control). Sixty-nine bone scans were evaluated. Late planar imaging was carried out in all cases, and single-photon emission tomography (SPET) was performed additionally in 34 of these cases. Complications were observed in four grafts. They occurred less frequently in revascularized grafts than in non-revascularized grafts. Planar scintigrams performed within 14 days after reconstruction showed a significantly higher tracer uptake in grafts with an uncomplicated further course than in those which developed complications. Follow-up scintigrams after 1 and 3 months revealed a significant increase in tracer uptake in grafts with an uncomplicated course. This was not apparent in grafts which developed complications. The tracer uptake was estimated to be higher on the basis of the SPET scans as compared with the planar scintigrams. It is concluded that bone scintigraphy is of prognostic value in the evaluation of bone grafts used for mandibular reconstruction. SPET seems to be more sensitive than planar imaging for the assessment of graft viability.

Treatment of congenital pseudarthrosis of the tibia by microsurgical fibula transfer

Conventional methods for the treatment of congenital pseudarthrosis of the tibia (CPT) often lead to unsatisfactory results and so microsurgical fibula transfer (MFT) has appeared as an option to treat this challenging problem. In this series of 27 patients with CPT, we obtained satisfactory results in 23 as assessed by the timing of bone union and bone hypertrophy of the fibular transplant. The overall functional results were also good; in 18 patients, the residual shortening was less than 2 cm (with no limb shortening in 4) and in 7, shortening ranged between 2 and 4 cm. All 25 patients resumed normal walking without the help of braces after an average of 12 months. This report suggests that microvascular fibula transfers provide superior results in the treatment of CPT, especially when considering that many of such cases represented previous surgical failures.

Refinements in the iliac crest microsurgical free flap for oromandibular reconstruction

Development of the iliac crest microsurgical free flap has greatly improved the surgical reconstruction of oromandibular defects. A decade of continuous utilization has established its efficacy and versatility. The utility of the flap has been continuously expanded by the introduction of new surgical techniques and adjunctive innovations. The advent of improved internal fixation systems, osteointegration, and neurocutaneous flaps has facilitated a more comprehensive oromandibular rehabilitation. The introduction of the split inner-cortex modification by the principle author served to refine the bony component and greatly reduces postoperative complications and donor site morbidity.

An experimental canine model of osteonecrosis: characterization of the repair process

Osteonecrosis of the femoral head was induced in dogs by a process of deep freezing, accompanied by stripping of the soft-tissue attachments from the femoral neck and intertrochanteric area, in an effort to develop an experimental model to study treatment modalities for avascular necrosis of the hip. Immediate uniform necrosis was created in a defined area. Thereafter, spontaneous healing originated mainly from the adjacent viable bone by migration of undifferentiated mesenchymal tissue into the necrotic bone, genesis of fibrosis, and, finally, formation of new bone. Osteogenesis occurred primarily through intramembranous ossification without a preexisting template. Quantitative measurements showed a difference in the rates of ingrowth and revascularization of the necrotic area during the fibrotic and osteogenic phases of the healing. The de novo osteogenesis was slower than the migration of fibrosis. These findings indicate that, without osteotomy, we can reproducibly create necrosis of bone in a defined area of the proximal femur and induce a reparative process that incompletely heals the defect. Although it does not fully simulate the human disorder of osteonecrosis, our experimental surgical model provides a basis for further laboratory investigation into the management of avascular necrosis of the femoral head.