Takeshi Miyawaki

Clinical outcome in cranioplasty: critical review in long-term follow-up.

Various materials have been proposed for cranial reconstruction. Bone autograft and alloplasts such as polymethylmethacrylate (PMMA) and hydroxyapatite (HA) cement are most commonly used at the present time. Patients submitted for cranioplasty were evaluated. The prognostic factors influencing the results and the outcome were analyzed. Three hundred twelve patients who had 449 procedures performed by a single surgeon to reconstruct a calvarial deformity between 1981 and 2001 were studied. Post-tumor resection deformity was the main reason for cranioplasty (32.4%). Bone graft was the material of choice (69.5%). The main surgical site was the frontal bone (53.2%). Complications were observed in 23.6% of cases and were responsible for the least satisfactory results (P > 0.001), with infection and material exposure being the most critical complications. The eventual outcome was considered good in 91.8% of cases. The use of HA cement was associated with the worst results (P > 0.001). Bone grafts showed a high grade of partial resorption and required further surgery for correction. Multiple surgical procedures were correlated with a high rate of complications and an unsatisfactory outcome. Bone graft and PMMA are still the best materials in calvarial reconstruction. Even though HA cement is an osteoconductive material, it seems to induce what appears to be an immunoguided delayed inflammatory reaction that leads to thinning of the skin and exposure of the material, making secondary repair difficult. Before deciding which reconstructive option to use, a careful evaluation of the patient in terms of diagnosis, number of previous surgeries, and surgical site should be undertaken. If this is adopted, good results and a satisfactory outcome can be achieved on long-term follow-up.

Augmentation of the craniomaxillofacial region using porous hydroxyapatite granules

&NA; Augmentation of the craniomaxillofacial region is required for many aesthetic and reconstructive procedures. A variety of different materials and techniques have been used. Coralline hydroxyapatite has proved to have biocompatible properties as a bone graft substitute. This study further analyzes the use of porous coral‐derived hydroxyapatite granules in craniomaxillofacial augmentation for cosmetic and reconstructive purposes and evaluates the long‐term clinical result. This retrospective study reviewed the use of porous coral‐derived hydroxyapatite granules over a 20‐year period, between 1981 and 2001, in 180 patients, in whom 393 procedures were performed. The surgical technique is described and discussed. Statistical significance was evaluated by descriptive statistics and the correlation bivariate Spearmans test (p > 0.05). For 61.6 percent of the procedures, the surgical indication was reconstructive and in 38.4 percent, cosmetic. The maxilla was the most common site of surgery (44.3 percent), followed by the mandible (21.6 percent) and zygoma (15.4 percent). The complication rate was 5.6 percent (n = 22 of 393), with contour irregularities being responsible for 59 percent (n = 13 of 22). Both infection and granule extrusion were responsible for 1.3 percent of the complications. Good results were achieved in 96.4 percent of the procedures. Porous coral‐derived hydroxyapatite granules have shown considerable efficacy and versatility in craniofacial contour refinement and augmentation. They are stable, biocompatible, and safe. A sterile technique is advised, with care taken not to tear the periosteum in the pocket design and with subperiosteal placement of the granules, compaction of the granules at the site, overcorrection of 15 percent of the required total volume, watertight closure, and postoperative taping to prevent mobilization. The correct surgical indications and adherence to the principles stated above will result in a very satisfactory long‐term outcome. (Plast. Reconstr. Surg. 111: 1808, 2003.)

Bone-Lengthening for Symbrachydactyly of the Hand with the Technique of Callus Distraction

Background: Bone-lengthening in the hand and foot is a relatively new application for distraction osteogenesis. We present the operative treatment and postoperative outcome for four patients with Müller type-D symbrachydactyly of the hand who underwent metacarpal lengthening with use of a distraction device to establish pinch function. Methods: Four patients who underwent distraction osteogenesis for the treatment of congenital symbrachydactyly of the hand were evaluated over a thirteen-year period. The nondominant right hand was treated in two patients, and the nondominant left hand was treated in the other two. The patients included three boys and one girl; all patients had the operation between the ages of five and eleven years. Distraction osteogenesis was performed on the fifth metacarpal in one patient and on the fourth and fifth metacarpals in the remaining three, in whom both bones were lengthened simultaneously with use of a single device. Postoperative bone elongation was analyzed with radiographs made at the time of removal of the distractor. The sensory function of the treated fingers and any growth disturbance of the distracted bones were evaluated. Results: The mean duration of distraction was 37.3 days (range, thirty-two to forty-nine days), and the distractor was removed at a mean of eighty-four days after surgery. The bones were lengthened by a mean of 22.3 mm (81.6% of their original length) at a rate of 0.6 mm/day. Pinch function was improved in all patients. Conclusions: On the basis of our limited experience, we found that distraction osteogenesis of the metacarpals was an effective technique for the establishment of pinch function. We also found that an intramedullary Kirschner wire could maintain the alignment of the osteotomized bone. Although distraction requires a longer treatment period, it is apparently more effective than bone-grafting in terms of achieving adequate bone length. Simultaneous lengthening of two metacarpals also was found to be an effective technique.

Kimura disease: diagnostic imaging findings and surgical treatment.

We have encountered 11 cases of Kimura disease, comprising 10 males and 1 female. The ages at presentation ranged from 16 to 48 years, with a mean of 31.5 years. The sites of the subcutaneous masses were bilateral posterior auricularregions in two cases, frontal region in two cases, temporal region in two cases, head region in one case, parotid region in two cases, parotid and temporal regions in one case, and left earlobe in one case. The interval from onset to surgery ranged from 1 to 10 years, with a mean of 4.7 years. For diagnostic imaging, a combination of magnetic resonance imaging (MRI) and ultrasonography had a high diagnostic value. MRI depicted abnormalities at sites in contact with bone, such asposterior auricular regions, and sites with abundant soft tissue, such as parotid and cheek regions. Diffuse atrophy of subcutaneous fat was observed at the sites of the masses. On ultrasonography, the interior of lymph nodes was homogeneous and hyperechoic, whereas the periphery was hyperechoic, and blood vessels entering lymph nodes were clearly depicted. Surgery was performed in all cases. Postoperative adjuvant radiotherapy was conducted in one patient and radiotherapy and steroid therapy in one other patient. There were two relapses, and both were excised by repeated surgery. Surgical excision of the subcutaneous mass in Kimura disease has the advantages that the treatment period is short and precise histopathologic diagnosis can be obtained.

The effect of low-molecular-weight heparin in the survival of a rabbit congested skin flap.

Swelling and congestion of flaps are frequently seen postoperatively and can cause unexpected necrosis. According to previous reports, venous thrombosis seems to be a more frequent problem than arterial occlusion in both experimental and clinical surgery. Few satisfactory venous trauma models exist, and reports on experimental venous thrombosis are rare. The object of this study was to create a rabbit venous occlusion flap model and to evaluate the effect of low-molecular-weight heparin on this flap. Eight New Zealand rabbits were used in the pilot study, in which the ideal congested flap was investigated using a flap pedicle based on the central auricular artery with a skin pedicle 0, 1, 2, or 3 cm wide. The flap (3 x 6 cm) was designed on the central part of the left ear, and the central auricular vein and nerve, the former for venous return, were cut out at the base of the flap. The flaps with skin pedicles 0, 1, 2, or 3 cm wide showed mean necrosis length of 60.0, 9.3, 4.2, and 0.0 mm, respectively. The flaps with skin pedicles 0, 1, 2, or 3 cm wide showed mean necrosis of 100, 15.5, 7, and 0 percent, respectively. Therefore, the flap, based on a 1-cm-wide skin pedicle and the central auricular artery, was selected as an optimal congested flap model showing 15.5 percent necrosis. The congested flap was then elevated on the left ear of another 10 rabbits. Subcutaneous low-molecular-weight heparin (320 IU/kg) was administered immediately after surgery to five of the rabbits (the low-molecular-weight heparin group), and the remaining five were used as a control group. Fluorescein was injected 15 minutes after surgery to evaluate the circulatory territory of the flap, and the circulatory territory was measured 5 minutes after injection. The flaps were assessed 7 days after surgery by angiography, histology, and clinical findings. The circulatory territory was significantly greater in the low-molecular-weight heparin group (mean +/- SD, 39.2 +/- 3.0 mm) than the control group (mean +/- SD, 48.0 +/- 1.0 mm) (p < 0.001) assessed 7 days after surgery. The longest flap survival length in group A and group B ranged from 40 to 55 mm (mean +/- SD. 49.4 +/- 5.6 mm) and complete survival (mean +/- SD, 60.0 +/- 0.0 mm). The improvement in survival was statistically significant for group B compared with group A (p < 0.015). Histologic evaluation revealed moderate to severe venous congestion and inflammation in the control group, whereas there were minimal changes in the low-molecular-weight heparin group. Angiography of the flap revealed obvious venous occlusion in the periphery in the control group compared with the low-molecular-weight heparin group. The authors conclude that subcutaneous administration of low-molecular-weight heparin has a great potential to improve the survival length of a congested flap without major complications.

Easy tissue expansion of prelaminated mucosa-lined flaps for cheek reconstruction in a canine model

In head and neck reconstruction, there is sometimes the need for a skin flap lined with mucosa. The object of this study was to determine whether small pieces of mucosa grafted onto the undersurface of a skin flap can be expanded in a reasonable time to provide the material required to reconstruct a full-thickness cheek defect as a free flap. The study consisted of two phases: prelamination and expansion of the flap, and vascularized free-tissue transfer of the flap. Six adult mongrel dogs were used. First, a 5 x 10-cm flap based on the saphenous vessels was elevated on the lower leg, and then four 1 x 2-cm pieces of mucosa harvested from the tongue were grafted onto the undersurface of the flap. A tissue expander (5 x 10 cm) was then placed under the flap, and the incision was closed primarily. The expanders were initially filled with just enough normal saline to obliterate dead space immediately after surgery. The expansion was continued twice weekly for 3 weeks until sufficient expansion was obtained. Two of six flaps were followed for an additional 6 weeks after the 3-week expansion period to observe whether additional mucosa could be obtained. After measurement of the mucosal area, each flap was transferred as free flap to reconstruct an iatrogenic cheek defect. The increase of mucosal surface area was compared with the original graft, and differences were analyzed using the paired t test. All flaps were successfully expanded without any complications. Histologic evaluation revealed that grafted mucosa took well without evidence of graft necrosis, and the intergraft area was covered with histiocytes. Angiography revealed well-defined vascular structures covering the entire area of the flap. The new mucosal area (23.5 +/- 2.4 cm2) was significantly larger than the original mucosal graft (8.7 +/- 0.9 cm2) (p < 0.001). The net increase of the mucosal area was 172.9 +/- 32.4 percent. The increase of mucosal area in two flaps, following a 6-week consolidation period after 3 weeks of expansion, was only slightly greater (25.9 +/- 1.3 cm2) than those without the consolidation period (22.3 +/- 1.8 cm2). This increase of the mucosal area appears to be related to the amount of expansion, and not to the length of the consolidation period. The flaps were successfully transferred as free flaps to reconstruct the full-thickness cheek defects without major complications. Although a staged operation to allow flaps to mature is needed, the present procedure has the advantages of providing a mucosa-lined flap and allowing primary closure of the donor site. The authors conclude that expansion of this flap has great potential in reconstructive surgery.

Trapezoid bone fracture.

Fractures of the carpal bones involve only a single bone or complex bones with or without ligament rupture. However, fractures of the trapezoid are rarely seen. Because the trapezoid is fastened to the trapezium, capitate, and scaphoid by strong ligaments, fracture or dislocation is limited by this rigid fixation. The authors present a single bone fracture of the trapezoid in a 40-year-old man. A tomogram of the carpal bone was useful in diagnosing the trapezoid fracture. The mechanism for development of fracture of the trapezoid alone is unknown. However, fracture of the trapezoid seemed to occur when the wrist joint was forced with excessive flexion stress that was placed on the trapezoid through the second metacarpal bone indirectly. This occurred in the same manner that a walnut is broken with nutcrackers.

Multicenter study of wound healing in neurofibromatosis and neurofibroma.

Based on clinical experience, the senior author has become convinced that wounds produced to correct the deformities of patients with neurofibromatosis (NF-1) have produced remarkably good scars, the interesting feature being that progression to keloid or hypertrophic scar is rare. The other point noted was that this situation did not change, no matter the patients race or skin color. There have been few reports describing or discussing this hypothesis. The purpose of this study was to investigate whether wounds produced in the patients with NF-1 produce keloid or hypertrophic scars. The patients with solitary neurofibroma were also included in this study; these were compared with the NF-1 group. This was conducted as a multicenter study. Patients with neurofibromatosis/solitary neurofibroma, who were operated on from 1990 to 2000, were evaluated by reviewing their medical charts and photographs retrospectively. The patients were treated in centers from five different countries. The analysis was undertaken based on the following points: 1) age and sex at surgery; 2) race of the patients; 3) past and family histories of hypertrophic scar and keloid; 4) surgical site(s); 5) diagnosis, NF1 or solitary neurofibroma; 6) surgical complications; 7) number of reoperations to manage the complications; 8) adjuvant therapy for the tumor; 9) depth of the tumors; and 10) incidence of malignant degeneration. A total of 101 cases with neurofibromatosis or solitary neurofibroma was analyzed. The age at surgery ranged from 1 year 6 months to 74 years; sex ratio was 47 males and 54 females. The racial distribution of the patients was 13 white, 13 black, 3 Hispanic, and 58 Asian. There was no past or family history of hypertrophic scar or keloid. The surgical sites were head and neck in 70 cases, trunk in 20 cases, upper extremities in 22 cases, and lower extremities in 20 cases. The clinical diagnosis was NF-1 in 57 cases, solitary neurofibroma in 35 cases, plexiform neurofibroma in four cases, and no distinct clinical diagnosis in five cases. There were no other types of neurofibromatosis. Hematoma and white wide scar were the main postoperative complications found in six cases of NF-1. Infection was also noted in four cases. However, no patient developed hypertrophic scar or keloid in the neurofibromatosis group, whereas two cases showed hypertrophic scar in the solitary neurofibroma group. The outcome showed that the patients with NF-1 and plexiform neurofibroma, no matter the racial group, produce good scars without keloid or hypertrophic changes, whereas solitary neurofibroma has a potential to cause hypertrophic scar.

External filling ports in tissue expansion: confirming their safety and convenience.

After the senior author introduced tissue expanders with externalized filling ports, their use has continued to be standard in almost all of our tissue expansion cases.1–4 Its use has also been reported in other centers.5–9 Even though it has distinct clinical advantages for both the surgeon and the patient, there has been reluctance to use this technique because of an anticipated high infection rate. In this study, all patients who underwent tissue expansion with external filling ports in the last 10 years were surveyed. The purpose of this follow-up study was to document the complications and advantages of the technique

Osteochondroma of the mandibular body.

We have treated four cases of osseous ostechondromas arising on the mandibular body, where this tumor rarely presents on the craniomaxillofacial bones. There were no recurrences after simple surgical resection of these tumors.