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Biomedical subjects

F C Wei

Publications and source records attributed to F C Wei.

At least 37 records · Page 2Linked to original sources
PubMed2001

Mandibular reconstruction with fibula osteoseptocutaneous free flap and osseointegrated dental implants.

The fibula osteoseptocutaneous free flap is ideal for reconstruction of composite mandible defects. Osseointegration is possible and advantageous. Primary osseointegration of dental implants is a safe and reliable procedure in selected groups of patients, promoting early total oral rehabilitation with restoration of both function and cosmesis. Further studies are necessary to assess the specific indications for osseointegration teeth in patients with malignant tumors and in those patients who have received radiation therapy.

Adult↗
PubMed2001

[Experimental study on bioglass application in extending alveolar bone crest in rabbit].

OBJECTIVE: To observe the effect of Bioglass guiding bone regeneration and forming normal new bone in extending alveolar bone crest by surgery. METHODS: Thirty-six rabbits were randomly divided into three groups. The first group was treated with Bioglass and the second with hudroxyapectite (HA). The third group was control group. At 4 8 12 weeks after surgery, the condition of bone regeneration was observed with radiological and pathological methods. RESULTS: Statistical analysis showed that there was a significant difference between the third group and the other two groups (P<0.05). In addition, Bioglass can guide bone regeneration faster than hydroxyapatite, and it can be substituted by new bone to form completely normal bone. CONCLUSION: Since Bioglass is more effective than HA in guiding bone regeneration, it is an ideal bone graft substitute.

English Abstract↗
PubMed2000

Free flaps for reconstruction of the lower back and sacral area.

Free flap reconstruction of the lower back and sacrum is complicated by a paucity of recipient vessels and difficulties in postoperative care. From 1983 to 1997, six patients with intractable wounds of the lower back and sacral area were treated with free flaps. The flaps used were latissimus dorsi (three), combined latissimus dorsi and serratus anterior (one), and filleted leg tissue (two). The recipient vessels were the deep femoral vessels, the perforator vessels of the deep femoral system, the inferior epigastric vessels, and the superior gluteal and inferior gluteal vessels. The patients were observed in the intensive care unit for 1 week and kept in prone position for 4 weeks. All flaps survived and wounds healed primarily. For large or multiple defects of the lower back and sacrum, free tissue transfer is effective in achieving primary healing, particularly when local flaps are inadequate or have failed.

Adult↗
PubMed2000

Microcirculatory changes following reperfusion insult in diabetic rat skeletal muscles.

We investigated the microcirculatory changes of ischemia/reperfusion injury in the diabetic rat cremaster muscle as well as the therapeutic effect of insulin. Streptozotocin-induced diabetic rats were maintained hyperglycemic for up to 8 weeks or were treated with insulin in the diabetic period. The rat cremaster muscle was prepared as an island flap and subjected to 2-h clamp ischemia followed by 1-h reperfusion. In nonischemic conditions, effective concentrations for 50% response (EC50) of serial orders of arterioles to norepinephrine were higher in diabetic muscles. Ischemia/reperfusion insult significantly decreased the EC50 of arterioles in the normal group, but not in the diabetic group. Light microscopy showed that the diabetic cremasters had more collapsed capillaries and smooth muscle-disarranged arterioles. Insulin therapy showed significant improvement in the diabetes-caused reduction of perfused capillary density, but not in the contractility of the diabetic arterioles. These results indicate that diabetes mellitus may damage the skeletal muscle microvasculature irreversibly and make it less responsive to autonomic regulation. Insulin therapy can improve capillary perfusion, but not the microvascular reactivity of diabetic muscles.

Animals↗
PubMed2000

An outcome study of thumb reconstruction using microvascular toe transfer.

The purpose of this study was to evaluate outcomes following microvascular toe to thumb transfer in a cohort study using the Michigan Hand Outcomes Questionnaire, the 36-item Short-Form Health Survey, the Lower Limb Function Questionnaire, and standardized hand function tests. Twenty-one patients who had unilateral, isolated thumb amputations at the metacarpophalangeal joints were studied: 16 patients had toe transfer and 5 patients did not have reconstruction. The mean follow-up period was 7.2 years (range, 3-13 years). Toe transfer patients showed statistically significantly better overall hand function (effect size = 1.4), ADL (effect size = 3.4), work performance (effect size = 2.1), aesthetics (effect size = 1.9), and satisfaction (effect size = 1.1). Functional testing showed that strength and dexterity of the toe transfer hands were comparable to the opposite normal hands. Foot donor site morbidity was minimal. No significant difference was found in the mean Lower Limb Function Questionnaire scores between the toe transfer patients (1.4) and the amputation patients who did not undergo reconstruction (1.6). The results of our study showed that patients with toe transfer have better hand function than patients with thumb amputations at the level of the metacarpophalangeal joints.

Adult↗
PubMed2000

The versatile anterolateral thigh flap: a musculocutaneous flap in disguise in head and neck reconstruction.

In search of an alternative soft tissue free flap donor site to radial forearm flap and rectus abdominis flap in head and neck reconstruction, we used the anterolateral thigh flap for reconstruction of various defects in the head and neck in 59 patients. The aim was to demonstrate the versatility of this donor site and propose a new approach to achieve a safer flap dissection. With the exception of three cases, all defects resulted from excision of malignant tumours. The defects were categorised as full thickness defects of the mandible (33.9%), full thickness defects of the cheek (52.5%) and others (13.6%). During the flap dissection a direct septocutaneous pedicle was observed in 12% of the cases. In the remaining cases there were only musculocutaneous perforators and the flaps were raised either as a split vastus lateralis musculocutaneous flap (72%) or as a perforator flap (16%), depending on the required thickness. Total flap survival was 96.7% with one total and one partial failure and two re-explorations (3.3%). The mean follow-up time was 7.1 months (range: 1-12 months). In conclusion, the anterolateral thigh flap is a versatile and dependable flap that can be adapted to any type of defect by modifying the flap design and composition. It should be considered to be a musculocutaneous flap of the vastus lateralis muscle that can also be raised as a perforator flap. When harvested and used in this context, the flap dissection becomes very safe and consistent, nullifying the only major disadvantage associated with this donor site.

Adolescent↗
PubMed2000

Free colon transfer for pharyngo-oesophageal reconstruction.

This report describes free transfer of transverse colon for reconstruction of the hypopharynx and cervical oesophagus. The transverse colon based on the middle colic vessels was used in three patients following laryngo-pharyngo-oesophagectomy for hypopharyngeal squamous carcinoma. There were no flap failures or intra-abdominal complications. Solid diet was well tolerated. Transverse colon is easy to harvest, has a long vascular pedicle, wide diameter and good ischaemic tolerance. Contrast studies showed it to be a wide bore passive conduit. Compared with currently available options these features may allow better outcome in pharyngo-oesophageal reconstruction and warrant further evaluation.

Adult↗
PubMed2000

Selection of donor nerves--an important factor in end-to-side neurorrhaphy.

We have examined the effects of end-to-side neurorrhaphy on peripheral nerve regeneration using the median nerve as recipient nerve and either the antagonistic radial nerve or the agonistic ulnar nerve as donor nerves in rat upper limbs. A perineural window was created in all cases. Motor recovery up to 16 weeks postoperation was tested with the grasping test. No recovery of motor function was evident after end-to-side neurorrhaphy of the median nerve to the antagonistic radial nerve, whereas six of eight rats with end-to-side neurorrhaphy to the agonistic ulnar nerve achieved 367 g +/- 47 g grasping power as compared to 526 g +/- 6 g in end-to-end coapted control animals. No significant difference in flexor digitorum sublimus-motor nerve conduction velocity was found among all three groups. Radial nerve stimulation produced simultaneous contraction of both extensor and flexor muscles of the lower arm that disabled any coordinated movement of the paw. Histology (toluidine blue, acetylcholinesterase-stain) showed multiple regenerated (motor)-axons distal to the coaptation site in the median nerve. Reinnervation of the median nerve solely by the respective donor nerve was demonstrated by a retrograde double labelling technique. These results show that averaged 70% muscle power as compared to end-to-end neurorrhaphy with well coordinated muscle function can be achieved by axonal sprouting through end-to-side neurorrhaphy if an agonistic nerve is used as donor nerve. However, satisfying results are unpredictable. Antagonistic nerves show the ability to induce axonal regeneration, but no useful function can be expected.

Anastomosis, Surgical↗
PubMed2000

Nerve transfer to the median nerve using parts of the ulnar and radial nerves in the rabbit--effects on motor recovery of the median nerve and donor nerve morbidity.

In this study, motor re-innervation of the median nerve by transfer of one-third, one-half, and two-thirds of either the agonistic ulnar nerve or the antagonistic radial nerve was investigated in both extremities of 20 rabbits. Recipient median nerve: Muscle contraction force of the flexor digitorum sublimus muscle after a one-third and a one-half of the ulnar nerve transfer achieved an average of 75 and 97% muscle power respectively as compared to conventional end-to-end neurorrhaphy. Muscle contraction force after one-third or one-half of the radial nerve transfer was significantly lower (36%). Donor nerves: Extensor carpi radialis muscle or flexor carpi ulnaris muscle contraction force 6 months postoperatively demonstrated a significant decrease after a one-half ulnar nerve and a two-thirds ulnar or radial nerve transfer, but not after a one-third transfer of either radial or ulnar nerves. Histologically, the number of axons in the re-innervated median nerve and both donor nerves distal to the coaptation site seemed to follow variable patterns. It was concluded that in the rabbit use of one-third of the agonistic ulnar nerve for re-innervation of the median nerve results in useful motor recovery with negligible donor site morbidity. Clinically, this technique may offer an alternative option for proximal nerve injuries or for free functioning muscle transplantations.

Animals↗
PubMed2000

Indications and limitations of angiography before free-flap transplantation to the distal lower leg after trauma: prospective study in 36 patients.

The necessity for routine angiography in evaluation of the vasculature of recipient legs prior to microsurgical free-tissue reconstruction still remains controversial. This prospective study was designed to determine the indications and limitations of angiography pertinent to this issue. The protocol consisted of palpation of dorsalis pedis and posterior tibial artery pulsation and lower-limb angiography prior to surgery, as well as intraoperative observation of the posterior tibial, anterior tibial, and peroneal arteries. Thirty-six patients were included who were treated from November, 1993 to December 1998. In five patients either the posterior tibial pulse (1), the dorsalis pedis pulse (3), or both pedal pulses, including the popliteal pulse (1) were not palpable preoperatively. These clinical findings correlated with the vascular lesion images on angiography. In two patients, pedal pulse palpation could not clearly be evaluated because of the injury. Among the 29 patients with both pedal pulses palpable, three patients angiographically presented an injury of the peroneal artery, and one patient a pseudoaneurysm of the anterior tibial artery. In none of the cases with at least one palpable pedal pulse (33), did preoperative angiography add relevant information which led to a plan change in the free-flap transfer. However, in two cases, severe scarring and fibrosis required an intraoperative change of the recipient vessel in one case, and a change of the anastomosis level and use of a vein graft, in the other case, although the angiography had demonstrated normal vascularity in both. The authors conclude that preoperative angiography is indicated only when both pedal pulses are not palpable, and that normal preoperative angiography does not guarantee the presence of vessels suitable for anastomosis.

Adolescent↗
PubMed2000

Role of the target in end-to-side neurorrhaphy: reinnervation of a single muscle vs. multiple muscles.

The authors examined the effects of end-to-side neurorrhaphy for reinnervation of the musculocutaneous nerve (Group A) which innervates the biceps muscle, compared to reinnervation of the median nerve which innervates multiple muscles in a rat model. Additionally, end-to-end neurorrhaphy to the musculocutaneous nerve using one-third of the median nerve (Group B) was investigated. End-to-end coaptation of the musculocutaneous nerve served as a control (Group C). In a grooming test, the biceps muscle function in Group A animals demonstrated a slower but nearly similar good recovery to Groups B and C. Biceps muscle contraction force investigated after 24 weeks demonstrated no statistically significant differences among all groups. In Groups A and B, no significant impairment of the donor median nerve function was found in a grasping test and the muscle contraction force of the flexor carpi radialis muscle, and histologic evaluation of the musculocutaneous nerve showed multiple regenerated axons distal to the coaptation site. Retrograde double-labeling in Group A animals showed reinnervation of the musculocutaneous nerve by median nerve axons located at the coaptation site. These results validate that end-to-side neurorrhaphy to a nerve innervating a single muscle is more efficient than to a nerve innervating multiple muscles, as demonstrated in an earlier study. The reason for this phenomenon is most likely that all sprouting axons are directed toward one target rather than toward multiple targets, with the latter situation resulting in a smaller number of axons and a variable distribution of axons per target. Since donor nerve sprouting axons were observed at the coaptation site, a relevance of the selected site for end-to-side neurorrhaphy is suggested. Both end-to-side neurorrhaphy and end-to-end neurorrhaphy, using one-third of the median nerve, led to useful functional recovery in this rat model, if an agonistic donor nerve is employed.

Anastomosis, Surgical↗
PubMed2000

Immediate Camitz opponensplasty in acute thenar muscle injury.

Thenar function impairment or destruction is not uncommon in hand crush injury or thumb avulsion injury. Although complete evaluation of thenar muscle function is difficult during an emergency setting because of skeletal instability and pain, if left untreated the injured hand may result in deficiency of opposition and may require secondary reconstruction. When the palmaris longus tendon is available from the open wound, a Camitz opponensplasty can be performed in the emergency operation setting even as an augmentation procedure for opposition if there is any suspicion of thenar muscle impairment. Seven patients with such injuries who underwent immediate Camitz opponensplasty were assessed to have an 80% angle of separation, a 90% angle of circumduction, and an 88% Kapandji test of the normal opposite hand. An emergency Camitz procedure provided a reliable, immediate one-stage reconstruction of thenar function.

Amputation, Traumatic↗
PubMed2000

Filleted toe flap for chronic forefoot ulcer reconstruction.

Chronic plantar and dorsal forefoot ulcer may result from injury, structural deformity, and abnormal sensation or circulation. It is not uncommon that the distal portion of the affected toes is deficient functionally in these patients. A filleted toe flap from the expendable functionless toe can provide a durable, stable, and sensate skin flap of 4 to 5.5 cm for coverage of the forefoot defect. In this report, five cases of dorsal forefoot defects and four cases of plantar forefoot defects due to ischemia (N = 3), trophic change (N = 2), and diabetes (N = 4) were treated with filleted toe flaps. One flap failed due to postoperative deep infection. The other eight filleted toe flaps survived but 2 patients underwent secondary amputations 7 months and 2 two years later because of secondary diabetic foot infections.

Adult↗
PubMed2000

Lateral-dorsal neurovascular island flaps for pulp reconstruction.

Finger pulp loss is often observed in daily practice. When the lateral and dorsal surfaces of the injured digit remain intact, a neurovascular island flap can be designed and raised from that part of the finger for pulp reconstruction. Two types of homodigital lateral-dorsal neurovascular island flaps were used in 17 patients (13 type I and 4 type II) for reconstruction of traumatic pulp loss on an emergent basis. The type I flap was used for the pulp defect less than 2.5 cm in length; the type II flap was designed for extensive pulp loss. The size of the pulp defect varied from 1.7 x 1.2 cm to 3.8 x 1.7 cm. All flaps survived completely without any partial loss. The mean follow-up was 17.7 months. The mean static two-point discrimination was 5.2 mm in type I flaps and 9.3 mm in type II flaps. All patients except five had full range of motion of the interphalangeal joint. These five patients (3 type I and 2 type II) had 10 to 20 deg reduction in flexion of the distal interphalangeal joints. The homodigital lateral-dorsal neurovascular island flap offers a durable, well-vascularized, sensate skin flap for one-stage pulp reconstruction in select patients. This technique is relatively simple, allows early postoperative mobilization, and has an acceptable surgical outcome.

Adult↗
PubMed2000

Devices for ischemic preconditioning of the pedicled groin flap.

BACKGROUND: Early division of the pedicled groin flap can be achieved by using ischemic preconditioning. The goal of this study was to investigate the devices available for ischemic preconditioning and determine which device is the most effective and results in lowest patient discomfort. METHODS: Rubber bands, custom-made Orthoplast sheets, long-nose locking pliers, intestinal clamps, and a pneumatic tourniquet device were used for ischemic preconditioning on 13 patients who sustained severe hand injuries with reconstruction of pedicled groin flaps. The devices were compared by using laser Doppler flowmetry and the patient's local pain levels. RESULTS: Twelve of 13 flaps were successfully divided at a mean period of 8.3 days by using a custom-made Orthoplast sheet or a pneumatic tourniquet device. All devices except the rubber bands could result in a biologic zero flow level. CONCLUSION: The pneumatic tourniquet device is the most desirable ischemic preconditioning device, having the advantages of excellent ischemic effect, easy application, and minimal discomfort.

Adult↗
PubMed2000

Conventional versus endoscopic free gracilis muscle harvest.

Compared with conventional techniques, the endoscopically assisted harvest of free tissue has advantages such as minimal interference with cosmesis and reduced donor-site morbidity. However, the procedure also requires training and has an extensive learning period. In this series of 22 patients, the initial gracilis muscle flaps were harvested using a conventional method; the subsequent flaps were harvested with the aid of endoscopic instrumentation. Endoscopically assisted gracilis muscle harvest in 16 patients was compared with open method harvest in six patients. The endoscopically assisted group had an average incision length of 6.5 cm; that of the conventional group was 15.5 cm. There was one reexploration in the endoscopically assisted group, but all flaps were transferred successfully. Using this minimally invasive technique of vascular and muscular dissection, assisted by endoscopic instruments designed for distal muscle dissection and transection, the gracilis muscles can be harvested within 40 minutes. We consider endoscopically assisted harvest of free gracilis muscle to be safe, relatively simple, and cost-effective.

Adult↗
PubMed2000

Widely split latissimus dorsi muscle flaps for reconstruction of long soft-tissue defects in lower extremities.

Although the latissimus dorsi is one of the largest and longest muscles in the human body, it is still sometimes inadequate for reconstruction of a soft-tissue defect of extensive length and dimension. Eight patients with such lower limb defects were treated with latissimus dorsi muscles split into two hemiflaps sequentially linked, one after the other like a chain. Six transfers were completely successful, one required reexploration for arterial occlusion, and two hemiflaps had a partial loss that could be managed by touching up the skin graft. The average split sequential-link muscle was 42 cm in length. Although two patients had a partial loss, we consider that the widely split single latissimus dorsi muscle can still be used reliably to reconstruct a long slender defect, or two separate, longitudinally located, medium-sized defects in the same leg.

Adult↗