Mitsunori Shigetomi

Recalcitrant posttraumatic nonunion of the humerus: 23 patients reconstructed with vascularized bone graft

We treated 23 patients with recalcitrant posttraumatic humeral shaft nonunion with vascularized bone grafts (fibula 10, femur 10 and scapula 3). 21/23 patients healed primarily. Venous thrombosis in the graft necessitated postoperative thrombectomy in 2 patients. Complications at the donor site were trivial. We used a vascularized fibular graft in patients with a large bone defect and with poor intrinsic stability of the nonunion site and a corticoperiosteal femoral graft in atrophic nonunion without a substantial bone defect. The scapula graft is easy to transfer to the surgical neck of the humerus on its pedicle.

Significance of elbow extension in reconstruction of prehension with reinnervated free-muscle transfer following complete brachial plexus avulsion.

&NA; Thirty‐one patients with complete avulsion of the brachial plexus underwent reconstruction of elbow extension by intercostal nerve transfer following reconstruction of prehension with either a single or double free‐muscle transfer. Long‐term results of elbow extension were evaluated in 24 patients. Reinnervation of the triceps muscle took longer than that of the transferred muscle on serial electromyographic examinations, and the eventual strength of the triceps muscle was weak. None attained M5 grade, 2 achieved M4 grade, 4 achieved M3 grade, 8 achieved M2 grade, 5 achieved M1 grade, and another 5 achieved MO grade. However, despite the weak recovery, 14 patients were able to obtain useful functional recovery of the triceps muscle, enabling it to stabilize the elbow joint against the transferred muscle, which acted as simultaneous elbow flexor and wrist or finger extensor. Elbow stability is imperative in order to obtain voluntary finger function following free‐muscle transfer. Should the triceps muscle fail to recover following intercostal nerves neurotization, transferring the reinnervated infraspinatus to the triceps is an optional procedure to provide stabilization of the elbow. (Plast. Reconstr. Surg. 100: 364, 1997.)

Functioning muscle transplantation after wide excision of sarcomas in the extremity

Free functioning muscle transplantation was performed after resection of 23 sarcomas in the extremity. There were 21 soft tissue sarcomas and two malignant bone tumors. The tumor resection was performed with a wide margin in all except two patients who had a marginal margin in a limited area. The consequent extensive soft tissue defect received free musculocutaneous flaps, the motor nerve of which was repaired in the recipient site. The most frequent procedure was latissimus dorsi transplantation to replace thigh muscles in 17 cases. The other donors included gracilis, tensor fascia lata, and rectus femoris, which were selected according to the site of defects. Patients were followed up for a mean of 60 months (range, 13-119 months). The grafted muscles showed reinnervation at a mean of 6 months postoperatively in all patients except for a 75-year-old patient. Obtained contraction of the muscles was powerful in 18 patients and fair in four patients. Performance of the salvaged limb significantly improved after recovery of the muscles. Although there were five distant recurrences, local recurrence was seen in one patient with systemic metastases. Because muscle loss could be compensated functionally for by the innervated free muscle transfer, the method encouraged surgeons to perform more radical tumor excisions and this may have contributed to the excellent local tumor control that was achieved. Thus, functioning muscle transplantation was extremely useful in limb salvage surgery from the functional and oncologic viewpoints.

Longer survival of rat limb allograft. Combined immunosuppression of FK-506 and 15-deoxyspergualin.

We studied the individual and synergistic effect of 3 immunosuppressive drugs, FK-506 (1 mg/kg/day), 15-deoxyspergualin (2.5 mg/kg/day) and cyclosporine (15 mg/kg/day) in a DA/Lewis rat limb allotransplantation model. 74 right hindlimb transplantations were performed. The median time for onset of rejection was 4 days in animals without immunosuppression, 37 days in animals receiving cyclosporine immunosuppression for 30 days, 61 days in animals receiving FK-506 for 30 days, 36 days in animals receiving a 30-day course of cyclosporine and, in the first 15 days, a course of 15-deoxyspergualin, and 76 days in animals receiving a 30-day course of FK-506 and 15-deoxyspergualin in the first 15 days. The combination of cyclosporine with 15-deoxyspergualin did not prolong graft survival and no synergistic effect was evident. In contrast, survival time in rat limb allografts receiving FK-506 and 15-deoxyspergualin was longer than in those receiving single FK-506 therapy. Our findings suggest a positive synergistic immunosuppressive effect with FK-506 and 15-deoxyspergualin in limb allotransplantation.

Skeletal reconstruction by vascularized allogenic bone transplantation: effects of statin in rats.

Background. Some statins have been reported to suppress the immune system and increase the expression of bone morphogenetic protein-2 gene that plays a pivotal role in bone regeneration. Methods. The effects of cerivastatin on skeletal reconstruction by vascularized bone allograft were investigated in a rat tibia-fibula graft model. After transplantation, the recipient rats were treated with vehicle, low-dose cerivastatin, high-dose cerivastatin, or cyclosporine A. Results. Transplanted bones treated with low-dose cerivastatin and vehicle failed to unite with the recipient bones. In contrast, high-dose cerivastatin induced the bone union as effectively as cyclosporine A. Histologically, high-dose cerivastatin-treated transplanted bones were nonvital, but new bone formation occurred at the outer layer of the nonvital cortex. Conclusion. These results indicate that statins could promote fracture healing. Because transplant recipients have the increased risks of osteoporotic fracture and hypercholesterolemia, statins may be a good choice in the treatment of these patients.

Successful nerve regeneration and persistence of donor cells after a limited course of immunosuppression in rat peripheral nerve allografts.

BACKGROUND The origin of Schwann cells and effect of a limited course of immunosuppression using cyclosporine (CsA) were examined in rat peripheral nerve allotransplants. METHODS Phenotypes of Schwann cells in groups without, with continuing, and with limited (12 weeks) CsA treatment were examined immunohistochemically in allogeneically and syngeneically transplanted animals from 4 to 36 weeks after transplantation. RESULTS In the group receiving no CsA, little nerve regeneration was obtained; donor Schwann cells were rejected and replaced by recipient cells. In continuing and limited-course CsA groups, successful nerve regeneration was achieved at postoperative week 36, as was also observed in the syngeneic group. Schwann cells in the continuing CsA group remained donor-derived. In the limited-course CsA group, graft rejection and loss of function occurred after the withdrawal of CsA, and donor Schwann cells were replaced by recipient cells in the part of the graft where rejection had been complete. However, many donor Schwann cells remained at week 36, when the rejection response subsided. CONCLUSION Possible clinical use of a limited course of immunosuppression was supported by this demonstration of long term persistence of donor Schwann cells.

Posttraumatic Radioulnar Synostosis Treated With a Free Vascularized Fat Transplant and Dynamic Splint : A Report of Two Cases

Two cases of posttraumatic radioulnar synostosis are presented. The patients were treated with excision of the cross-union and interposition of a free vascularized fat transplant. A newly devised pronation-supination dynamic splint was employed for 3 months postoperatively in both patients. After a 1-year postoperative follow-up, an increased range of motion was restored in both cases, and there was no evidence of recurrent synostosis formation in subsequent radiographs. We suggest that an interposed vascularized fat graft may be an ideal biologic barrier to fill the space created by cross-union excision.

Revascularized intercalary bone allografts with short-term immunosuppression with cyclosporine in the canine.

&NA; To study the healing process of vascularized intercalary bone allograft after withdrawal of immunosuppressive drugs, allotransplantation of the tibia diaphysis with a vascular pedicle was performed in eight adult mongrel dogs (group 2) and assessments were made both during administration and after discontinuation of cyclosporin A. As controls, similar grafts with the vascular pedicles were removed and reimplanted back to the same animals (five dogs, group 1). Allotransplantation of frozen stored bone without a vascular pedicle (10 dogs, groups 3A and 3B) were also compared. No union occurred in most cases of frozen stored bone allotransplant because the transplanted bone was resorbed, leading to loosening and subsequent failure of osteosynthesis with the plate and screws used. Under cyclosporin A immunosuppression, bony union (i.e., when trabeculae were seen crossing the graft‐recipient junction with obliteration of the junction line) occurred at almost similar time intervals in all dogs of group 2 (bone allotransplant with a vascular pedicle) by 3 months postoperatively, which was similar to those of group 1. No systemic side effects of cyclosporin A were observed. Cyclosporin A was discontinued 3 months following graft implantation. The bone graft became avascular within a week following withdrawal of cyclosporin A. However, bone union was maintained, and the transplanted bone never showed bone resorption, sclerosis, or fracture on serial radiographs up to the time the animals were sacrificed, between 5 and 14 months later. Histology at sacrifice showed that the transplanted allografts were being replaced at both ends by fresh bone derived from the transplantation bed. We conclude on the basis of the results of this study that solid bony union can be obtained in allotransplanted bone with a vascular pedicle if cyclosporin A is given for a brief period. After cyclosporin A is withdrawn, although the bone becomes nonviable secondary to rejection occurring in the blood vessels, its skeletal structure remains intact, enabling it to maintain its structural support while awaiting replacement by bony ingrowth from both ends of the graft.

Pedicle or free musculocutaneous flaps for shoulder defects after oncological resection.

Management of soft-tissue defects of the shoulder is described. Extensive defects of soft tissues with or without overlying skin were created after resection of sarcomas in five patients. Reconstruction was performed using musculocutaneous flaps, which included three pedicle latissimus dorsi and two free tensor fascia lata flaps. Simultaneous functioning replacement of the defects of the trapezius and deltoid muscles were each achieved in two patients. Primary wound healing was achieved, and each patient recovered good contour of the shoulder. Functional results were satisfactory in all patients with an average score of 93.4% (range, 83%–100%) using the system of the Musculoskeletal Tumor Society. The four functioning muscles recovered active contraction in the transferred position. The shoulder elevation was normal in three patients, and was 90° and 30° in one patient each. All patients remained disease-free at the time of latest follow-up. Thus, shoulder defects of the soft tissues can be managed appropriately with the two representative musculocutaneous flaps.

Effects of vitamin D analog, 22-oxa-1,25-dihydroxyvitamin D3, on bone reconstruction by vascularized bone allograft

We previously reported that vascularized bone allograft using immunosuppressants, such as cyclosporine A (CsA), is one approach for reconstruction of large bone defects in both experimental animals (Microsurgery 15:663; 1994) and clinically in humans (Lancet 347:970, 1996). Because immunosuppressive agents such as CsA induce significant side effects, including bone loss, other therapeutic agents supporting successful vascularized bone allografts have been sought after. We investigated the effects of 22-oxa-1,25-dihydroxyvitamin D(3) (OCT) on vascularized bone allograft, and compared its effects with CsA. Twelve-week-old DA rats with the major histocompatibility antigen (MHC) RT-1(a) were used as donors and age-matched Lewis rats with MHC RT-1(l) used as recipients. Allografted bones in rats treated with vehicle were rejected completely. Soft X-ray examination demonstrated that administration of OCT (0.5 microg/kg per day) for 12 weeks after bone graft induced bone union as effective as treatment for 12 weeks with CsA (10 mg/kg per day). Transplanted bones in OCT-treated rats showed higher bone mineral density than that in CsA-treated rats. Histologically, transplanted bones in OCT-treated rats at 12 weeks were nonvital, but these bones united with recipient vital bones. After cessation of 12 week treatment with OCT, new bone formation occurred around the grafted nonvital bones during a 9 month period. Transplanted bones in CsA-treated rats were vital and formed union with recipient bones, whereas cortical bones became thin when compared with nonvital bones in OCT-treated rats. Urinary deoxypyridinoline levels in rats treated with CsA were significantly higher than levels in rats treated with OCT, suggesting accelerated bone resorption in CsA-treated rats. These results suggest that OCT exerts an anabolic action on bone reconstruction by allogeneic bone transplantation.