Shigeru Mizumoto

Vascularised fibular grafts for reconstruction of the femur

From 1979 to 1990 we treated 20 patients with large bone defects or established nonunion of the femur by vascularised fibular grafts. There were 18 men and two women with an average age at operation of 36.6 years (16 to 69). Ten patients had infected nonunion, three had post-traumatic nonunion or a bone defect without infection, four had a defect after tumour resection, and three had other lesions. The mean length of the fibular grafts was 18.1 cm. Postoperative circulatory disturbances needed revision surgery in five patients, including three with circulatory problems in the monitoring flap, but not at their anastomoses. The outcome was successful in 19 of the 20 patients with bone union at means of 6.1 months at the proximal site and 6.6 months at the distal site. Three patients had fractures of the fibular grafts but all these united in two to three months after cast immobilisation.

Vascularized fibular grafts in the treatment of osteomyelitis and infected nonunion.

From 1976 to 1989, 33 patients with osteomyelitis and infected nonunion of lower extremity bones were treated with vascularized fibular grafts. There were 30 males and three females, and the ages at operation ranged from 17 to 69 years. There were 24 tibial lesions and nine femoral lesions. The fibular graft was performed immediately after lesional debridement in eight patients, but in 25 it was done secondarily after debridement and successful subsidence of inflammation. The mean interval between the last debridement and fibular grafting was ten weeks. Thirty of 33 grafts survived. The mean periods required to obtain radiographic bone union was 6.2 months at the proximal site and 6.3 months at the distal site. Local recurrence of infection occurred in four patients; all but one healed well with saucerization. Vascularized fibular graft is an effective procedure for the treatment of destructive osteomyelitis and infected nonunion.

Vascularized tail bone grafts in rats.

A new experimental model for vascularized cortico-cancellous bone grafts was established by investigation of vascular anatomy of the tail in 15 adult Fischer 344 rats and determination of the viability of vascularized tail bone grafts into the abdominal wall in 22 7-week-old rats. The tail bones of 40 rats were then raised on the pedicle of the caudal artery and its venae comitantes, transferred to a resected portion in the femur, and observed for 16 weeks. The vascularized graft showed marked reactive periosteal bone formation during the first and second weeks following transfer, and thereafter, the graft continued to show active bone formation. In transverse section, the sharp processes became rounded. In the cancellous bone, both bone resorption and bone formation were noticeably activated early after transfer, although resorption predominated and the amount of the cancellous bone consequently diminished. The nonvascularized grafts showed “creeping substitution.” The results suggest that morphologic adaptation occurs if living (i.e., vascularized) tail bones are transferred to long-bone femurs. (Plast. Reconstr. Surg. 91:502, 1993.)

Innervated radial thenar flap combined with radial forearm flap transfer for thumb reconstruction.

A radial thenar flap combined with radial forearm flap was used for the reconstruction of the ipsilateral thumb in four patients. Vascular supply of the combined flap was based on the radial artery and extending the vascular pedicle to the superficial palmar branch of the radial artery. The flap was sensated by the palmar branch of the superficial radial nerve. The size of the flap averaged 15 x 5 cm and the innervated region of the thenar eminence was an area approximately 5 x 3 cm located over the proximal parts of the abductor pollicis brevis and opponens pollicis muscles. The flap was transferred as a free flap in three patients and as an advancement flap in one patient. The flaps survived completely without complications. Satisfactory restoration of sensation was achieved in the flap area, as shown by 6 mm of average moving two-point discrimination. This combined flap may be a feasible reconstructive option for large palmar defects of the fingers such as degloving injuries.

Continuous local intra-arterial infusion of antithrombotic agents for replantation (comparison with intravenous infusion)

The success rate of replantation of amputated digits and limbs appears to be improved by local continuous intra-arterial infusion of urokinases, heparin and PGE1 at a daily dose of 240,000 I.U., 10,000 U, and 40 micrograms, respectively, for ten days, in comparison to intravenous infusion of the drugs. The purpose of this study was to investigate the difference between the haematological effects of intra-arterial and intravenous infusion. Accordingly coagulation and fibrinolytic enzyme levels were examined before, and at 4 and 12 hours after the start of infusion and on the 3rd and 10th postoperative days. Intra-arterial infusion was advantageous over intravenous infusion probably because the effect of general metabolism on drug levels was small, drugs exhibited immediate action and efficacy was localised. No particular side effects were demonstrated.

Experimental study of vascularized bone grafts in rat : Effect of mechanical loading on bone dynamics

We studied the etiology of postoperative hypertrophy of vascularized bone grafts in a murine experimental model. Syngeneic grafting of revascularized ulna to rat tibia was performed with (group 1) or without (group 2) mechanical loading. The effect of simple overloading on intact bone was studied by segmental resection of the radius (group 3). Bone dynamics were examined by histomorphological measurements. Significant hypertrophy was observed in the early postoperative period in both groups 1 and group 2. After the initial phase, bone growth continued and extensive remodeling was observed in group 1, while marked bone resorption was observed in group 2. Adaptive remodeling was also observed in group 3 after surgery, but was slower than that in groups 1 and 2. Early hypertrophy of vascularized grafts did not correspond to mechanical loading. These results suggest that mechanical loading is the principal factor responsible for remodeling in vascularized bone grafts for their adaptation to a new environment.

Treatment of Kienbock's disease with vascular bundle implantation and triscaphe arthrodesis

Since 1986, 21 patients with advanced Kienbock’s disease have been treated with vascular bundle implantation into the lunate and with triscaphe arthrodesis. The former is a biological approach for Kienbock’s disease and the latter is a biomechanical approach, both of which decrease the longitudinal stress on the diseased lunate as well as treat the accompanying rotary subluxation of the scaphoid. The 18 cases which were followed-up for more than 1 year were analyzed.

Non-radioactive coloured microsphere measurement of regional tissue blood flow for axial pattern flaps in rabbits

We administered non-radioactive coloured microspheres (NRACM) to measure the regional tissue blood flow (RTBF) of eight axial pattern flaps and four kidneys in four rabbits using four repeated injections into each animal. As a control, we used radioactive microspheres (RAM) for six kidneys in three rabbits. There were no significant differences for RTBF values between NRACM and RAM, between the numbers of microspheres used (2 x 10(6) and 4 x 10(6)), or between the number of injections. These results showed that NRACM is a useful and safe laboratory method.

Continuous Local Heparinization

After Komatsu and Tamai first performed the successful replantation of an amputated thumb in 1965 [1], 78 medical institutions in Japan reported 3126 cases of digit replantation up to July 1981 [2]. Thus, replantation had become an established surgical technique in Japan within little more than a decade after the world’s first digit replantation.

Vascularized Ulna Graft in the Rat

When a vascularized fibula graft was performed for a bone defect in the extremity long bones, significant hypertrophy was observed when the graft was transferred to a mechanically loaded lower extremity, but less hypertrophy was observed when it was transfered to the upper extremities. This phenomenon of hypertrophy is related to the imposed mechanical stress load [1–3]. We designed a murine experiment to clarify the etiology of postoperative hypertrophy of vascularized bone grafts. We performed syngeneic vascularized ulna transfer to a segmental bone defect in the rat, with or without mechanical loading. The bone dynamics of the grafts were examined by fluarochrome bone labeling and histomorphological measurement.