Yuzo Komuro

The histologic analysis of distraction osteogenesis of the mandible in rabbits

The process of bone formation in mandibular lengthening by distraction was studied in 30 rabbits. The mandible was subjected to a corticotomy, held in a neutral position for 2 weeks, and then lengthened at 0.18 mm per 12 hours for 24 days using a unilateral external fixation device (Orthofix M-100). On completion of the distraction, x-ray analysis showed that the distracted gap was filled with callus organized into three zones, namely, two sclerotic zones with a central radiolucent zone. These zones became indistinguishable from the adjacent preexisting mandible at 10 weeks after distraction. Histologically, new bone, which was formed by both intramembranous and endochondral ossification, underwent remodeling and resulted in cortical bone by 8 to 10 weeks after completion of distraction.

Mandibular lengthening by gradual distraction: analysis using accurate skull replicas

Bone lengthening in the upper and lower extremities by gradual distraction has become an accepted procedure. We have used an extraoral device to lengthen the mandible in four patients with unilateral mandibular hypoplasia. Using an accurate skull replica, the proposed corticotomy line, intended direction of lengthening, and appropriate position for the screws were determined. Following distraction, a significant increase in the dimensions of the affected mandible was obtained in each case. In this series, accurate skull replicas proved very useful for defining the anatomy, for surgical simulation and for pre- and postoperative evaluation.

correction of Pectus Excavatum and Pectus Carinatum Assisted by the Endoscope

&NA; Six patients with pectus excavatum and two patients with pectus carinatum had their conditions corrected by a partial costal cartilage resection with a sternal osteotomy through a 2.5‐cm to 4‐cm skin incision located just above the xyphoid process assisted by an endoscope. In addition to the incision, stab wounds of less than 3 mm in diameter were also made, in some cases, for insertion of the surgical instruments to facilitate the operation. The ribs and rib cartilages were exposed beyond the affected area through a prexyphoid incision under endoscopic control. The mobility of the skin incision site was thus enhanced, and it was possible to perform most of the subperichondrial partial costal cartilage resection under direct visualization. The pleura was freed from the sternum under endoscopic visualization. The advantages of this technique include minimal operative scars and the ability to free the pleura from the sternum under endoscopically magnified visualization, which prevents rupturing of the pleura in the retrosternal area.

Correction of the cleft nasal deformity with an L-shaped iliac bone graft.

We describe our technique for correcting a cleft lip nasal deformity using L-shaped iliac bone grafts to achieve additional structural support and the desired nasal projection and profile. Augmenting the nasal bridge creates the illusion of a narrower nose. Further, the columellar portion of the L-shaped graft provides stabilization, eliminating the “seesaw” effect of the bridge graft on the fulcrum of the bony bridge, which can lead to a depressed tip and loss of the root indentation. Clinical and radiographic observation has revealed that this method of correction has consistently produced satisfactory results.

Proliferating Trichilemmal Tumor on the Dorsum of the Hand

A patient with a proliferating trichilemmal tumor on the dorsum of a hand is described. A surgical excision was performed, and the skin defect was covered with a distally based posterior interosseous island flap. In the operation, an iron fragment was found beneath the mass, and this was thought to have triggered development of the tumor.

Experience with U-shaped gluteal thigh flap for reconstruction of radionecrosis in the sacral region.

The gluteal thigh flap first reported by Hurwitz in 1980 can provide a large reliable flap for coverage of the sacrogluteal and perineal regions. This flap can be extended quite some way along its axial inferior gluteal vessels, but its width is limited to approximately 10 cm if direct approximation of the donor site defect is required. In this article, we report a U-shaped modification of the gluteal thigh flap for efficient use of the flap in covering a large defect in the sacrogluteal region.

Multiple neurilemomas of the ulnar nerve: a case report.

Multiple neurilemomas in a patient involving the same peripheral nerve is quite rare. We report a case of multiple neurilemomas involving the ulnar nerve.

Endoscopic correction of pectus excavatum

Pectus excavatum has been most commonly corrected by either the sternal elevation or turnover methods. Both of these procedures require a long skin incision in the anterior chest wall. Endoscopic techniques have been introduced into the treatment of pectus excavatum since 1994 to minimize the skin incision to approximately 1 inch. Thirty patients with pectus excavatum (25 men and 5 women) underwent surgery employing the centimeter incision method assisted by the endoscope. The mean age at the time of surgery was 11.9 years (range, 4-45 years). The patients were classified as having one of three types of pectus excavatum: Type I (symmetrical and localized) was seen in 18 patients (60%), type II (symmetrical and diffuse) was seen in 5 patients (17%), and type III (localized or diffuse but asymmetrical) was seen in 7 patients (23%). Although the results of the thoracic cage correction achieved using our procedure were excellent overall, the results were best for type I, with clear improvement achieved in the funnel index-0.48 to 0.63. All of the patients recovered well without any severe complications, and both the patients and their families found the results obtained using this method to be quite satisfactory, especially because of the minimal postoperative scar.

Experimental study on growth of epiphysial plate: free graft in rabbits

The growth potential of a free graft of an epiphysial plate was investigated in rabbits. Two epiphysial plate grafts were harvested from each iliac crest. One was grafted to the head (onto bone) and the other to the ear (onto cartilage). Both of the epiphysial plates enlarged to a maximum height of 1.4 cm and became similar to iliac crests. Enchondral ossification was observed up till approximately 28 weeks of age. We conclude that an epiphysial plate has growth potential after free heterotopic transplantation.

Accessory scrotum: a case report and review of the literature

An accessory scrotum is a rare congenital anomaly. The authors report the case of an accessory scrotum in the mid-perineum which was not associated with any other anomalies, and describe the surgical result.