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Biomedical subjects

F C Wei

Publications and source records attributed to F C Wei.

At least 73 records · Page 4Linked to original sources
PubMed1999

Free fibula osteoseptocutaneous-pedicled pectoralis major myocutaneous flap combination in reconstruction of extensive composite mandibular defects.

Lateral composite mandibular defects resulting from excision of advanced oral carcinoma often require mandible, intra-oral lining, external face, and soft-tissue bulk reconstruction. Ignorance of importance soft-tissue deficit in those patients may cause significant morbidity and functional loss. Such defects, therefore, can be reconstructed best with a double free flap technique. However, this procedure may not be feasible for every patient or surgeon. An alternative procedure is a free fibula osteoseptocutaneous flap combined with a pedicled pectoralis major myocutaneous flap. This combination was used in reconstruction of extensive composite mandibular defects in 14 patients with T3/T4 oral squamous cell carcinoma. All patients were men, and the average age was 54.3 years. The septocutaneous paddle of the fibula flap was used for the mucosal lining of the defects while the bony part established the rigid mandibular continuity. The pectoralis major flap then covered the external skin defect in the face and cheek, and the dead spaces left by the extirpated masticator muscles, buccal fat, and parotid gland. One free fibula flap failed totally, and one pectoralis major flap developed marginal necrosis. At the time of final evaluation, nine patients (64.3 percent) were alive, surviving an average of 25.7 months. All patients eventually regained their oral continence and an acceptable cosmetic appearance. In conclusion, the fibula osteoseptocutaneous flap plus regional myocutaneous flap choice is a successful and technically less demanding alternative to the double free flap procedures in reconstruction of extensive lateral mandibular defects.

Adult↗
PubMed1999

Management of secondary soft-tissue deficits following microsurgical head and neck reconstruction by means of another free flap.

Secondary soft-tissue deficits may develop following a microsurgical reconstruction in the head and neck region because of inadequate planning or chronic effects of radiotherapy. Although most cases could be managed with alternative methods, free flaps might be necessary in difficult cases. Herein are described 11 cases of microsurgical head and neck reconstruction in which secondary soft-tissue deficits required transfer of another soft-tissue free flap. All patients had malignant tumors treated with surgical resection, and their defects were reconstructed with free flaps. Seven patients received either preoperative or postoperative adjunctive radiotherapy. These patients gradually developed signs and symptoms of soft-tissue deficiency in the reconstructed area, and a soft-tissue free flap transfer was required for treatment within an average of 21.5 months of their initial reconstruction. Five rectus abdominis, one rectus femoris, one latissimus dorsi, one tensor fasciae latae myocutaneous, one radial forearm, one medial arm, and one dorsalis pedis flap were used for this purpose. All flaps survived completely. The average follow-up time was 32 months. Significant improvement was achieved in all cases, and no further major surgical procedures were required. Secondary soft-tissue deficits that could not be predicted or prevented during the initial microsurgical reconstruction may be treated successfully by a subsequent free soft-tissue transfer in selected cases.

Adult↗
PubMed1999

Outcome comparison in traumatic lower-extremity reconstruction by using various composite vascularized bone transplantation.

Lower-extremity injury may present as a composite soft-tissue and bone defect, resulting directly from trauma or subsequent debridements. These composite defects often require vascularized osteocutaneous flaps for an effective, staged reconstruction. Among various donor sites, the vascularized fibular flap is generally considered the best option because of its inherent advantages. However, when the fibular flap is not available, iliac and rib flaps become the alternative choices. The purpose of this retrospective study was to compare the functional results of the alternatively chosen bone flaps (iliac and rib flaps) with those of the fibular flaps.

Adolescent↗
PubMed1999

Reconstruction of bilateral metacarpal hands with multiple-toe transplantations.

Bilateral metacarpal hands, if not treated properly, leave a patient without prehensile ability in both hands. Since 1990, six patients with bilateral metacarpal hands caused by accidents have undergone reconstruction with multiple-toe transplantations. Four or five toes were used for each patient, with a total of 27 toes transplanted to the hands. There was no toe loss. One nonunion in a middle-finger reconstruction was treated successfully with bone grafting. Secondary operations for functional improvement included one joint fusion and one flexor tendon tenolysis. Only one patient required excision of a plantar callus 42 months postoperatively, whereas the other five patients reported no major donor-site problems in an average 57 months of follow-up time. The six patients continue all their daily activities independently. Although their jobs were changed, all adult male patients were able to return to regular work. Principles of reconstruction to achieve satisfying prehensile function combined with minor donor-site morbidity in bilateral metacarpal hands include an adequate soft-tissue coverage before toe transplantations, selection of digits to be reconstructed based on functional and individual requirements, selection of toes and number of toes to be harvested based on consideration of usefulness for the hands and of foot morbidity, and consideration of thenar function in planning the sequence of transplantations. In conclusion, given thorough planning, multiple toe-to-hand transplantations can provide adequate prehensile function in reconstructed bilateral metacarpal hands with acceptable donor-site morbidity.

Adult↗
PubMed1999

Prefabrication of jejunum for challenging reconstruction of cervical esophagus.

A significant benefit exists for a jejunal replacement of the cervical esophagus, if indicated. The absence of available recipient vessels may impede free tissue transfer. If vascular induction between a vascular carrier and the selected jejunal segment is done as a kind of flap prefabrication, the jejunal interposition flap can be used without the need for complex microsurgery.

Adult↗
PubMed1999

Systematic mutation analysis of the catechol O-methyltransferase gene as a candidate gene for schizophrenia.

OBJECTIVE: Catechol O-methyltransferase (COMT) is involved in the degradation of catecholamine neurotransmitters. Recent linkage studies of schizophrenia and molecular studies of velocardiofacial syndrome suggest that the COMT gene might be a candidate gene for schizophrenia. METHOD: The authors systematically searched for mutations and microdeletion of the COMT gene in 177 Chinese schizophrenic patients from Taiwan; 99 comparison subjects were also studied. RESULTS: Five molecular variants were identified: c.186C > T at exon 3, c.408C > G at exon 4, c.472G > A at exon 4, c.597G > A at exon 5, and c.821-827insC at the 3' untranslated region. However, no differences in the genotype and haplotype frequencies of these molecular variants between the schizophrenic and comparison subjects were detected. Furthermore, no microdeletion was identified among the patients. CONCLUSIONS: These data suggest that the COMT gene does not play a major role in the pathogenesis of schizophrenia, and the genotypic overlap between schizophrenia and velocardiofacial syndrome was rare in this cohort.

Catechol O-Methyltransferase↗
PubMed1999

Development of a biodegradable antibiotic delivery system.

Antibiotic beads have been used as a drug delivery system for the treatment of various surgical infections. In this study, the copolymer 50:50 poly(DL-lactide):co-glycolide was mixed with vancomycin powder and hot compressing molded at 55 degrees C to form five types of biodegradable antibiotic beads. The beads were placed in 1 mL of phosphate buffered saline and incubated at 37 degrees C. The phosphate buffered saline was changed daily, and the removed buffer solutions were stored at -70 degrees C until the antibiotic concentration in each sample was determined by high performance liquid chromatography system assay. The concentration of vancomycin in each sample was well above the breakpoint sensitivity concentration (the antibiotic concentration at the transition point between bacterial killing and resistance to the antibiotic) for more than 32 days. The release was most marked during the first 48 hours. All copolymer 50:50 poly(DI lactide):co-glycolide biodegradable beads released high concentrations of the antibiotics in vitro for the time needed to treat bone infections (4 to 6 weeks). The diameter of the sample inhibition zone ranged from 6.5 mm to 10 mm, and the relative activity of vancomycin ranged from 12.5% to 100%. Copolymers with low heat of formation temperatures are required for making a controlled release system to prevent antibiotic decomposition, which occurs when using the hot compressing molded method. The rate and duration of release from the antibiotic beads can be adjusted by varying the diameter of the beads. This offers a convenient method to adjust the release rate to meet the specific antibiotic requirements for different patients.

Absorbable Implants↗
PubMed1999

Reverse venous outflow of a free fibular osteocutaneous flap: a salvage procedure.

The authors report 2 patients with a massive bony defect of the tibia due to chronic osteomyelitis. They reconstructed the defect using a free vascularized fibular osteocutaneous flap. Unfortunately, venous insufficiency was diagnosed 24 hours postoperatively. The previous anastomosed veins were promptly explored. The peroneal veins of the vascularized fibular bone graft were noted to be full of thrombi. After thrombectomy, the vessels became very fragile and broke down easily. It was impossible to achieve normal antegrade venous outflow from the previous vein of the donor graft; however, they found that distal runoff of the peroneal vein achieved a reverse venous outflow from the donor graft. The great saphenous vein was dissected and reanastomosed to achieve adequate venous drainage. This procedure may offer an alternative treatment for a flap with venous insufficiency.

Humans↗
PubMed1999

In vitro and in vivo photosensitizing capabilities of 5-ALA in vascular endothelial cells.

BACKGROUND: The object of our study is to evaluate the feasibility of photodynamic therapy for complicated hemangiomas. We studied the effect of the photosensitizing agent 5-aminolevulinic acid (5-ALA) in both in vitro and in vivo models. METHODS: The in vitro photosensitizing activity of 5-ALA was examined in a microvascular endothelial cell (MEC) culture system. 5-ALA was added in various concentrations and the cells were illuminated at 630 nm. The percentage of MEC killed was measured by either a Live/Dead assay or an lactate dehydrogenase (LDH) assay. The effect of varying the light energy dose delivered at 630 nm after the administration of 5-ALA was studied by determining the amount of necrosis produced in chicken combs. RESULTS: The combination of 5-ALA at a concentration of 35 micrograms/ml, and illumination by 100 mW/cm2 of laser light at 630 nm wavelength, caused 50% cell kill in the MEC culture system. Chicken combs of animals that received 200 mg/kg of 5-ALA and illumination at a power density of 80 mW/cm2 had a depth of injury of 362.5 +/- 27.6 microns upon histological examination. Those combs that received 100 or 120 mW/cm2 showed a depth of injury of 732.5 +/- 29.1 and 792.5 +/- 36.0 microns respectively. CONCLUSION: 5-ALA is effective in sensitizing human MEC to laser illumination. However, the degree of absorption and tissue destruction in different anatomical structures should be considered in future clinical studies.

Aminolevulinic Acid↗
PubMed1999

Soft tissue management using palatal mucosa around endosteal implants in vascularized composite grafts in the mandible.

Excessive thickness and mobility of the skin flap and lack of a vestibular sulcus in composite vascularized bone grafts for mandibular reconstruction limit the usefulness of endosteal implants to support a prosthetic device. Palatal mucosal grafts and a simple acrylic stent are an excellent means to overcome these problems. The technique is presented in this paper.

Acrylic Resins↗
PubMed1999

Free flaps for soft tissue coverage in the hand and fingers.

With mastery of conventional methods, free flaps are indicated in selected cases for coverage of the hand and fingers. Careful preoperative planning, delicate intraoperative management, and postoperative physiotherapy are the mainstays for success in functional recovery and aesthetic result. Thin flaps of good vascularity are favored for coverage of the hand and finger. For hand surgeons, the lateral arm fasciocutaneous or fascia flap, toe flaps, and the latissimus dorsi flap seem to be the easiest and most useful free flaps applicable to most situations.

Contracture↗
PubMed1999

Combined third and fourth toe transplantation.

Multiple toe transplantation has been established as an effective technique for restoring prehensile ability in the metacarpal hand. The combined third and fourth toe transplant is a new toe transplant that has been developed for bilateral metacarpal hand reconstruction. Since 1991, the combined third and fourth toe transplant was added to the armamentarium of toe transplants for metacarpal hands, although its role in metacarpal hand reconstruction has not been described previously. This article introduces the indications for combined third and fourth toe transplant, outlines relevant vascular anatomy, and discusses technical considerations pertaining to toe harvest and transplantation.

Adult↗
PubMed1999

Strategies in multiple toe transplantation for bilateral type II metacarpal hand reconstruction.

Multiple toe transplantation has been established as an effective means of restoring prehensile function in the metacarpal hand. The attainable outcome, however, must be weighed against potential donor site morbidity. Restoration of prehensile function in bilateral type II metacarpal hands can be achieved by reconstructing three opposable digits in the dominant hand and two opposable digits in the nondominant hand. This article outlines the strategy for optimizing functional outcome and discusses the rationale behind toe selection to reduce donor morbidity.

Adult↗
PubMed1999

Vascularized toe joint transplantation.

The vascularized toe joint transfer is an alternative to arthrodesis. For optimal functional results, the patient must have normal-functioning muscle and associated tendons, effecting joint motion. Although vascularized toe joint transfer permits long-term preservation of joint architecture and cartilage, the goal of achieving normal range of motion for a reconstructed digit is still elusive. Reconstruction of the extensor mechanism can be worthwhile in selected patients because more useful motion can be achieved even if the result falls short of normal.

Adolescent↗
PubMed1999

Endoscopic carpal tunnel release.

BACKGROUND: Endoscopic carpal tunnel release was developed by Okutsu and Chow in 1989. Many reports have indicated that endoscopic carpal tunnel release diminishes postoperative pain and accelerates the recovery time. METHODS: In a series of 1278 carpal tunnel release procedures (in 948 patients), 1214 were performed with a modified Menon endoscopic method and the remaining 64 with an open procedure. The patients with idiopathic carpal tunnel syndrome were followed for at least 3 months. RESULTS: Of the endoscopic release patients, 80.9% recovered grip strength equal to or greater than preoperative levels within 4 weeks, whereas in the open procedure group, the rate was only 59.3%. The difference was statistically significant (p = 0.00011). An immediate complication was one median motor nerve severance. There were 24 conversions to a conventional open procedure during endoscopic release. In the endoscopic group, 81% developed scar tenderness over the thenar crease, 31% developed new sensory disturbance, and 4% developed pillar pain. CONCLUSION: Endoscopic release facilitated the recovery of grip strength and diminished the frequency of scar tenderness. However, neurovascular injury should be carefully prevented.

Adult↗
PubMed1999

Donor-site morbidity comparison between endoscopically assisted and traditional harvest of free latissimus dorsi muscle flap.

Endoscopically assisted harvest of free latissimus dorsi muscle flaps is being used more frequently in reconstructive microsurgery because it requires a smaller incision and leaves a more acceptable scar in the donor site. Donor-site morbidity was compared between groups of 22 latissimus dorsi muscles harvested using the endoscopically assisted technique and 26 using the traditional technique. The results revealed no statistically significant differences in the amount of intraoperative bleeding, the incidence of postoperative hematoma and seroma, and the incidence of donor-site wound infection as assessed by the surgeon. However, a patient questionnaire revealed that even though it did not reach a statistically significant difference, endoscopically assisted harvest of the latissimus dorsi muscle had less pain and allowed earlier and better movement of the upper extremity of the donor site. The patients' attitudes and feelings about the scar and overall satisfaction were also higher in the endoscopic group, which demonstrated a statistically significant difference.

Endoscopy↗
PubMed1998

Reversible metabolism of clozapine and clozapine N-oxide in schizophrenic patients.

1. To characterize the interconversion process between clozapine and its metabolite clozapine N-oxide (CNO), eight healthy male schizophrenics were administered a single dose of clozapine or CNO in a randomized crossover manner. 2. Using a general pharmacokinetic model for the interconversion process, the mean total clearances of clozapine and CNO were 28.45 L/hr and 45.30 L/hr, respectively. These values were similar to the values obtained by the usual model-independent method of pharmacokinetic analysis. 3. When administered clozapine, mean CNO plasma concentrations of 17.7 +/- 16.4 ng/ml were slightly lower than the other clozapine metabolite-desmethylclozapine (DCLOZ) plasma levels of 24.4 +/- 8.6 ng/ml at the 12 hour time point. When CNO was administered, plasma concentrations at the 12 hour time point of clozapine were twice the amount of CNO (28.1 +/- 8.9 ng/ml vs 14.4 +/- 8.8 ng/ml). 4. DCLOZ plasma concentrations were detected in all patients upon clozapine administration. Upon CNO administration, only one patient had detectable plasma DCLOZ levels. 5. The interconversion process of clozapine and CNO could partially account for the wide interpatient variability reported for clozapine plasma concentrations in schizophrenic patients.

Adult↗