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Biomedical subjects

F C Wei

Publications and source records attributed to F C Wei.

At least 19 recordsLinked to original sources
PubMed2006

Functional MR imaging of the human sensorimotor cortex after toe-to-finger transplantation.

BACKGROUND: A model of toe-to-finger transplantation has been used in studying peripheral nerve regeneration and central reorganization. It was found that recovery of sensory perception depends not only on peripheral reinnervation but also on central integrative mechanisms. OBJECTIVE: Our aim was to investigate functional changes of the brain and somatotopic representation of the transplanted toes after toe-to-finger transplantation. MATERIALS AND METHODS: Six patients who had toe-to-finger transplantation from 3 to 8 years earlier underwent motor and sensory functional MR imaging studies of transplanted toes and opposite corresponding normal fingers. The motor task was performed by repetitively tapping of the transplanted toe or finger against the thumb, whereas the sensory task was applied by tactilely stimulating the pulp of the transplanted toe or finger. RESULTS: The main activation areas from both types of stimulations were located in the expected location of the finger homunculus of the primary sensorimotor cortex. In addition, activated volumes from the transplanted toes were significantly greater than those from the opposite fingers (P = .017 for motor task and P = .005 for tactile sensory task, paired samples Student t test). CONCLUSIONS: Functional recruitment in the primary sensorimotor cortex seemed to have occurred following toe-to-finger transplantation. The transplanted toe was somatotopically represented in the hand area.

Adolescent↗
PubMed2002

Clinical experience of 1284 free anterolateral thigh flaps.

The past decade has witnessed yet another rebirth in reconstructive surgery with the introduction of the so-called "perforator flaps". The demonstration of safe harvest of skin flaps based on dissection of cutaneous pedicles regardless of the course taken (through muscle or septum) has been revolutionary in allowing much greater choice in donor sites. Based on our experience in 1284 cases, the anterolateral thigh (ALT) region has proven itself to be an ideal donor site with reliable vascularity, ease of harvest and tremendous versatility. Inclusive in this flap is a large cutaneous territory, multiple components (adipofascial, muscle, fascia and skin) and possibility of chimeric applications. Although particularly useful in the head and neck (911 cases), the ALT flap was applied to reconstruct defects throughout the body. Donor site morbidity is limited as well. In short, the anterolateral thigh flap represents one of the most useful soft tissue flaps for free tissue transplantation.

Anastomosis, Surgical↗
PubMed2001

Free vascularized bone grafts for reconstruction of traumatic bony defects of mandible and maxilla.

Small bone defects of the mandible and maxilla can be surgically treated with conventional bone grafts provided local conditions are optimal for bone healing. However, when the bone defect is large, is associated with soft tissue loss, or when conventional bone grafting fails, a free vascularized bone graft often becomes an important alternative to ensure adequate healing. As free vascularized bone grafting is today considered a more reliable procedure for bone reconstruction, with success rates over 96%, we prefer to treat even smaller segmental bone defects with this technique when local conditions are less than ideal. The technique also allows for simultaneous insertion of osteointegrated dental implants at the time of vascularized bone grafting, thereby facilitating earlier total oral rehabilitation.

Bone Transplantation↗
PubMed2001

Specificity of reinnervation and motor recovery after interposition of an artificial barrier between transected and repaired nerves in adjacency--an experimental study in the rat.

Non-specific re-innervation of target organs caused by misdirected axonal growth at the repair site is regarded as one reason for a poor functional outcome after peripheral nerve transsection and repair. This study investigates the rate of aberrant re-innervation and its influence on motor recovery in the rat sciatic nerve using artificial sheets as barrier between tibial and peroneal nerves. The sciatic nerve was transsected and repaired as follows: epineural sutures (A x 6), fascicular repair of tibial and peroneal nerves respectively (B x 8), and the same as in group B, but separating both nerves using an Integra-sheet with silicone (C x 8), or Integra without silicone (D x 8). As control, solely the tibial nerve was transsected and repaired (E x 5). Final investigations after 4 months revealed that in group C, 50% of the Integra-silicone sheets were dislocated. No dislocation was found in group D. Muscle contraction force of the gastrocnemius muscle was significantly higher in group E as compared to all other groups. However although not significant, group D showed a consistently higher muscle contraction force than groups A, B, and C. Histology in groups A, B, and C with dislocated sheets demonstrated multiple axons growing from the tibial to the peroneal nerve and vice versa. In groups D and E, no such axonal growth was visible. These findings were confirmed by a significantly higher rate of specific reinnervation of the soleus muscle using sequential retrograde double labelling technique. Results of this study suggest that an artificial sheet such as Integra bears the potential of preventing aberrant re-innervation between repaired adjacent nerves resulting in improved motor recovery. Clinically, this technique may be of importance for brachial plexus, sciatic nerve, and facial nerve repair.

Animals↗
PubMed2001

Mimicking lip features in free-flap reconstruction of lip defects.

This paper introduces a technique of lip reconstruction using free flaps in which recognisable landmarks are mimicked by strategic placement of flap junctions. The technique was applied in 15 patients undergoing reconstruction of combined cheek and lip defects using single (n= 9) or double (n= 6) free flaps. Attention to flap design and strategic placement of flap junctions successfully created the vermilion-cutaneous junction, oral commissure and labiomental groove. The presence of these distinguishing features improved the appearance of the reconstructed lip.

Adult↗
PubMed2001

Concomitant ipsilateral pedicled fibular transfer and free muscle flap for compound tibial defect reconstruction.

Three patients with compound injuries of the lower extremities were treated with pedicle fibular grafts and a free muscle flap concomitantly. There were 1 female and 2 male patients, all of whom sustained high-energy trauma in a motor vehicle accident. The bone defect of the tibia ranged from 8 to 12 cm. The size of the soft-tissue defect ranged from 24 x 15 cm to 28 x 15 cm. All patients underwent preoperative angiography to ensure the patency of the peroneal artery and to avoid its use by risking viability of the leg. All patients were treated with an antegrade-flow pedicle fibular graft. The fibular graft was inserted as a single strut in 2 patients and as a double-barrel strut in 1 patient. The pedicle of the free muscle flap was anastomosed to the distal runoff of the fibular bone flap. All free muscle flap transfers succeeded without complication. Bone scans performed on postoperative day 7 showed viability of transferred bone. The average time to radiological union was 9 months, and the average time to full weight bearing was 12 months. Screw loosening occurred in 2 patients and osteomyelitis was noted in another patient who was treated successfully with sequestrectomy and antibiotics. Indications for this technique are a large segmental bone defect with a huge soft-tissue defect, and patency of the peroneal artery and at least one other major artery. This method provides the advantages of one-stage reconstruction, avoidance of contralateral donor site morbidity, easy control of infection, and chance for early weight bearing. When selected carefully, this technique can be considered when one wants to avoid a two-stage, two free flap transfer.

Accidents, Traffic↗
PubMed2001

Interposition of a pedicle fat flap significantly improves specificity of reinnervation and motor recovery after repair of transected nerves in adjacency in rats.

Despite highest standards in nerve repair, functional recovery following nerve transection still remains unsatisfactory. Nonspecific reinnervation of target organs caused by misdirected axonal growth at the repair site is regarded as one reason for a poor functional outcome. This study was conducted to establish a method for preventing aberrant reinnervation between transected and repaired nerves in adjacency. Rat sciatic nerve was transected and repaired as follows: epineural sutures of the sciatic nerve (group A, n = 6), fascicular repair of tibial and peroneal nerves respectively (group B, n = 8), and, as in group B, separating both nerves using a pedicle fat flap as barrier (group C, n = 8). As control only, the tibial nerve was transected and repaired (group D, n = 5). Muscle contraction force of the gastrocnemius muscle was significantly higher in group C as compared with groups A and B after 4 months. Muscle weight showed significantly lower values in group A as compared with groups B, C, and D. Histologic examination in group C revealed little growth of axons from the tibial to the peroneal nerve and vice versa. This axon crossing was observed only when gaps between the fat cells were available. These findings were confirmed by a significantly lower rate of misdirected axonal growth as compared with groups A and B using sequential retrograde double labeling technique of the soleus motoneuron pool. We conclude that a pedicle fat flap significantly prevents aberrant reinnervation between repaired adjacent nerves resulting in significantly improved motor recovery in rats. Clinically, this is of importance for brachial plexus, sciatic nerve, and facial nerve repair.

Adipose Tissue↗
PubMed2001

Bilateral small radial forearm flaps for the reconstruction of buccal mucosa after surgical release of submucosal fibrosis: a new, reliable approach.

Oral submucous fibrosis is a collagen disorder affecting the submucosal layer and often severely limiting mouth opening. Previous surgical treatments have been disappointing. This article introduces a new surgical approach: reconstructing the bilateral buccal mucosa with two small radial forearm flaps. The surgical method includes the complete surgical release of fibrotic buccal mucosa and, if necessary, a bilateral coronoidectomy and temporalis muscle myotomy. From 1997 to 1999, 15 patients with moderate-to-severe trismus received reconstructive surgery, for a total of 30 small radial forearm flaps after surgical release. The flap size was between 1.5 x 5 and 2.5 x 7 cm. All donor sites were directly closed, and all flaps survived completely, except for one with partial necrosis. Six flaps required minor revisions because of size redundancy. Two patients developed buccal cancer in the area of reconstruction. At an average of 12 months' follow-up, the inter-incisal distance averaged 33 mm, an increase of 17 mm compared with the preoperative value. The donor-site morbidity was minimal, except in one heavy smoker who developed dry gangrene of his fingertips. The use of two small free forearm flaps for buccal mucosa reconstruction allows more radical release of fibrotic tissue. Coronoidectomy and temporal muscle myotomy further contribute to the effect of trismus release. The combined effects of this approach have consistently given good results. An aggressive approach toward surgical treatment of this precancerous lesion also facilitates the detection of cancer at an early stage.

Adult↗
PubMed2001

Free anterolateral thigh flap for extremity reconstruction: clinical experience and functional assessment of donor site.

From August of 1995 through July of 1998, 38 free anterolateral thigh flaps were transferred to reconstruct soft-tissue defects. The overall success rate was 97 percent. Among 38 anterolateral thigh flaps, four were elevated as cutaneous flaps based on the septocutaneous perforators. The other 34 were harvested as myocutaneous flaps including a cuff of vastus lateralis muscle (15 to 40 cm3), either because of bulk requirements (33 cases) or because of the absence of a septocutaneous perforator (one case). However, vastus lateralis muscle is the largest compartment of the quadriceps, which is the prime extensor of the knee. Losing a portion of the vastus lateralis muscle may affect knee stability. Objective functional assessments of the donor sites were performed at least 6 months postoperatively in 20 patients who had a cuff of vastus lateralis muscle incorporated as part of the myocutaneous flap; assessments were made using a kinetic communicator machine. The isometric power test of the ratios of quadriceps muscle at 30 and 60 degrees of flexion between donor and normal thighs revealed no significant difference (p > 0.05). The isokinetic peak torque ratio of the quadriceps and hamstring muscles, including concentric and eccentric contraction tests, showed no significant difference (p > 0.05), except the concentric contraction test of the quadriceps muscle, which revealed mild weakness of the donor thigh (p < 0.05). In summary, the functional impairment of the donor thighs was minimal after free anterolateral thigh myocutaneous flap transfer.

Adult↗
PubMed2001

The outcome of failed free flaps in head and neck and extremity reconstruction: what is next in the reconstructive ladder?

The indications for free flaps have been more or less clarified; however, the course of reconstruction after the failure of a free flap remains undetermined. Is it better to insist on one's initial choice, or should surgeons downgrade their reconstructive goals? To establish a preliminary guideline, this study was designed to retrospectively analyze the outcome of failed free-tissue transfers performed in the authors hospital. Over the past 8 years (1990 through 1997), 3361 head and neck and extremity reconstructions were performed by free-tissue transfers, excluding toe transplantations. Among these reconstructions, 1235 flaps (36.7 percent) were transferred to the head and neck region, and 2126 flaps (63.3 percent) to the extremities. A total of 101 failures (3.0 percent total plus the partial failure rate) were encountered. Forty-two failures occurred in the head and neck region, and 59 in the extremities. Evaluation of the cases revealed that one of three following approaches to handling the failure was taken: (1) a second free-tissue transfer; (2) a regional flap transfer; or (3) conservative management with debridement, wound care, and subsequent closure by secondary intention, whether by local flaps or skin grafting. In the head and neck region, 17 second free flaps (40 percent) and 15 regional flaps (36 percent) were transferred to salvage the reconstruction, whereas conservative management was undertaken in the remaining 10 cases (24 percent). In the extremities, 37 failures were treated conservatively (63 percent) in addition to 17 second free flaps (29 percent) and three regional flaps (5 percent) used to salvage the failed reconstruction. Two cases underwent amputation (3 percent). The average time elapsed between the failure and second free-tissue transfer was 12 days (range, 2 to 60 days) in the head and neck region and 18 days (range, 2 to 56 days) in the extremities. In a total of 34 second free-tissue transfers at both localizations, there were only three failures (9 percent). However, in the head and neck region, seven of the regional flaps transferred (47 percent) and four cases that were conservatively treated (40 percent) either failed or developed complications that lengthened the reconstruction period because of additional procedures. Six other free-tissue transfers had to be performed to manage these complicated cases. Conservative management was quite successful in the extremities; most patients' wounds healed, although more than one skin-graft procedure was required in 10 patients (27 percent). In conclusion, a second free-tissue transfer is, in general, a relatively more reliable and more effective procedure for the treatment of flap failure in the head and neck region, as well as failed vascularized bone flaps in the reconstruction of the extremities. Conservative treatment may be a simple and valid alternative to second (free) flaps for soft-tissue coverage in extremities with partial and even total losses.

Extremities↗
PubMed2001

Microsurgical tissue transplantation or replantation in patients with psychoneurological impairment.

Sometimes patients with a psychoneurological impairment present with a traumatic injury that requires either microsurgical replantation or free-tissue transfer. We reviewed 38 patients undergoing 40 microvascular operations; the patients included 26 patients with psychological impairment (group 1), 3 with mental disability (group 2), and 9 with an acquired head injury and consciousness disturbance (Glasgow Coma Scale score < or =14) (group 3). Patients with a psychological impairment, especially those with a self-inflicted injury, are often uncooperative and do not recognize the necessity of restorative procedures. A multidisciplinary approach by the trauma surgeon, plastic surgeon, psychiatrist, and neurosurgeon, with coordinated assistance from the physician, nurse, therapist, and family, is required for treatment. In our study the success rate of replantation was 77.8 percent (14 of 18); for free tissue transfer the success rate was 95.5 percent (21 of 22). The overall success rate of microsurgical procedures (87.5 percent, 35 of 40) was similar to that in the population at large. Patients with psychological impairment tend to be lost during follow-up; therefore, their functional results may be poorer than expected. Nonetheless, patients with psychological impairment should not be deprived of the benefits of restorative surgery.

Adult↗
PubMed2001

Debrisoquine 4-hydroxylase (CYP2D6) genetic polymorphisms and susceptibility to schizophrenia in Chinese patients from Taiwan.

Debrisoquine 4-hydroxylase (CYP2D6) is one of the cytochrome P450 enzyme families that metabolize many compounds. Polymorphic activities of debrisoquine 4-hydroxylase were suggested to be associated with some complex diseases, such as cancer and Parkinson's disease. Schizophrenia is also a complex disorder, and hence we are interested in understanding if the CYP2D6 gene is a susceptibility gene for schizophrenia in Chinese. We determined the genotype and allele frequencies of four molecular variants of CYP2D6 gene (i.e. 188C/T, 1934G/A, 2938C/T and 4268C/G) in 162 Chinese schizophrenic patients and 94 non-psychotic control subjects from Taiwan. No significant differences of allele or genotype frequencies of three polymorphisms (i.e. 188T/C, 2938C/T and 4268C/G) were detected between patients and control subjects. The 1934A allele, which accounts for the majority of poor metabolizers in Caucasians, was not detected in either patients or control subjects, indicating that the 1934A allele is very rare in Chinese. Our data suggest that the CYP2D6 gene may not be a susceptibility gene for schizophrenia in Chinese schizophrenic patients.

Alleles↗
PubMed2001

Double-coping technique in prosthesis fabrication for osseointegrated teeth implantation: case report.

Reconstruction of segmental mandibular defects resulting from trauma, infection, or tumor resection still remains difficult. Although cosmetic improvement was seen in patients who had immediate reconstruction of the mandibular continuity, normal mastication and deglutition could not be achieved by conventional removable dentures. Since 1988, the treatment protocol has been modified to use endosseous root-form implants to support dental prostheses instead of the conventional removable prostheses in these patients. There are 2 types of prostheses that can be constructed over dental implants: (1) a removable implant overdenture and (2) a fixed detachable prosthesis. Although the latter better meets in patients' psychological needs, it may present problems such as phonetic discrepancies, food impaction, difficult home care, and poor esthetics if the patient has a high lip line. In addition, it is not easy to fabricate accurately in the laboratory. To overcome these problems, a case is presented to illustrate the use of another fixed-type prosthesis, a double-coping technique, for fabricating dentures so that any discrepancy between the inner and outer copings can be filled by cement. The technique not only improves the shortcomings of fixed detachable prostheses but also satisfactorily meets patients' desire for normal mastication and deglutition. Follow-up after 4 years showed no significant changes around the implants by clinical and radiographic examinations.

Dental Implantation↗