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Biomedical subjects

C C Chuang

Publications and source records attributed to C C Chuang.

10 recordsLinked to original sources

Emergency free-flap transfer for reconstruction of acute complex extremity wounds.

Nine patients with complex extremity injuries were treated with emergency free-flap transfers over a 3 1/2-year period. The transferred emergency free flaps were performed to cover exposed vital structures. All flaps survived without infection. Complete and careful assessment of the systemic condition of the patient and the nature of the injured extremity is mandatory. Emergency free-flap transfers may salvage the limb or finger and may improve the functional and aesthetic results with the shortest possible hospital stay.

Accidents

Molecular cloning of a member of a new class of low-molecular-weight GTP-binding proteins.

We report the cloning of a low-molecular-weight GTP-binding protein that appears to be the first member of a new class of G proteins. This G protein was cloned from the HT4 neural cell line and has the closest homology to the rab, sec4, and ypt1 members of the low-molecular-weight (LMW) G-protein family. The amino acid sequence identity is only 30% with these other LMW G proteins, but in the four conserved GTP-binding domains, amino acid identity increases to 50-100%. A unique feature that distinguishes this G protein from other LMW G proteins is its carboxy-terminal amino acid sequence -Cys-Cys-Pro. In keeping with the current nomenclature for other members of the ras superfamily, we will designate this new class as rah (ras-related homolog). On the basis of sequence homology, rah may function in vesicular trafficking and possibly in neurotransmitter secretion.

Amino Acid Sequence

Combined second and third toe transfer.

Historically, restoration of hand function following multiple digital amputation has been unsatisfactory. The evolution of digital reconstruction with toe transfer has enabled surgeons to reestablish prehension in these severely injured hands. A 4-year experience with 26 consecutive combined second and third toe transfers to replace missing adjacent fingers was reviewed in order to delineate the indications and technical considerations and to emphasize prevention of donor-site complications. Combined second and third toe transfer is reserved for adjacent finger amputations proximal to the digital web space with remaining fingers no longer than the small finger. Radial amputations are replaced with contralateral combined toe units, while ipsilateral toes are more ideal for ulnar amputations. Limited dorsal and plantar skin flaps extending only to the midpoint of the first and third digital web spaces allow for direct donor-site closure and uncomplicated healing. Maintenance of the plantar metatarsal arch by avoiding metatarsal shaft osteotomies or bone grafting-shortened metatarsals eliminates potential gait disturbances. When properly applied in selected patients, this single-stage microsurgical procedure can restore prehensile function, improve the appearance of the hand with multiple digital amputations, and preserve near-normal donor-foot function.

Adolescent

Simultaneous multiple toe transfers in hand reconstruction.

Our experience with simultaneous transfer of two or more toe units to the same hand where multiple digits were missing is presented. Forty-six toes from 38 feet were transferred to reconstruct 19 hands in 19 patients. The transfers consisted of 7 combined second and third toe units and 32 single toes. Three patients had a primary and 16 patients had a secondary reconstruction. There was one complete and one partial failure. The two-point discrimination ranged from 6 mm to protective sensation. Total active movement averaged 57 degrees in the thumb and 127, 93, 71, and 68 degrees, respectively, in the fingers reconstructed at middle phalanx, proximal phalanx, metacarpophalangeal joint, and metacarpal head. Pulp-to-pulp pinch averaged 2.4 kg in patients who had thumbs reconstructed and averaged 3.0 kg in patients who had normal thumbs. There was no cold intolerance, and no significantly disabled foot occurred except one with scissoring deformity. Simultaneous multiple toe transfer in hand reconstruction is feasible without increased complications both in primary and secondary wound conditions. It is time-effective and cost-effective.

Accidents, Occupational

Reconstruction of Achilles tendon and calcaneus defects with skin-aponeurosis-bone composite free tissue from the groin region.

Eight patients had reconstructive surgery for soft-tissue, associated Achilles tendon, and calcaneus defects on the posterior aspect of the ankle. In group A, those patients with skin, soft-tissue, and Achilles tendon loss were treated with free groin flaps that included sheets of the external oblique aponeurosis based on the superficial circumflex iliac vessel. The groin flap provided skin coverage, and the aponeurosis was rolled to form a tendon-like structure to replace the Achilles tendon. In group B, those patients with an additional calcaneus bone loss were treated with free iliac osteocutaneous flaps, together with the external oblique aponeurosis based on the deep circumflex iliac vessel. The iliac bone was then utilized to reconstruct the calcaneus defect. All composite free tissue transfers were successful, except in two group B patients who suffered partial skin loss. The advantages of this technique are (1) a single, one-stage procedure, (2) faster wound healing with fewer adhesions of the reconstructed Achilles tendon, and (3) good cosmesis and minimal morbidity at the donor site.

Achilles Tendon

Three successful digital replantations in a patient after 84, 86, and 94 hours of cold ischemia time.

Three successful digital replantations were performed on a patient after 84, 86, and 94 hours of prolonged cold ischemia time. Both the intraoperative and postoperative courses were smooth. Functional evaluation 8 months after operation revealed a normal speed of sensory recovery and nail growth. The atrophic changes in all three replants are mild. Total active movement was 45, 100, and 70 degrees in the replanted left thumb, left index finger, and right thumb, respectively. There is no cold intolerance. The overall functional result is satisfactory. Replantation of an amputated digit that is properly cooled immediately after injury should be attempted in selected patients even after prolonged ischemia time.

Adult

Reconstruction of the thumb with a trimmed-toe transfer technique.

The trimmed-toe transfer is a new modification of the existing great-toe transfer technique for thumb reconstruction. This procedure was devised to circumvent patient concerns regarding overly large reconstructed digits following total great-toe-to-hand transfer. This technique involves reduction of both the bony and soft-tissue elements along the medial aspect of the transferred great toe in order to produce a more normal sized thumb. Follow-up of the initial 20 patients from 1983 to 1986 demonstrates good stability, grip strength, and pinch strength. Although compared with total great-toe transfer a modest reduction in joint motion of trimmed toes has been observed, the overall appearance and usefulness of the reconstructed thumbs have been excellent.

Adolescent

Reconstruction of a hand, amputated at the metacarpophalangeal level, by means of combined second and third toes from each foot: a case report.

Reconstruction of all four fingers that were amputated at the metacarpophalangeal (MP) joints of the right hand of a 17-year-old male patient was performed by simultaneous transfer of the combined second and third toes from each foot at the level of the metatarsophalangeal joint. Fifteen-month follow-up showed acceptable cosmesis with satisfactory functional results. The patient had no foot discomfort, even after prolonged walking and running.

Adolescent

Fibular osteoseptocutaneous flap: anatomic study and clinical application.

The vascularized fibular graft has been expanded to an osteoseptocutaneous flap by including a cutaneous flap on the lateral aspect of the lower leg. The cutaneous flap can serve not only for postoperative monitoring of the grafted fibula, but also as extra skin coverage to replace substantial skin defects or prevent tight closure of the wound. From anatomic studies of 20 cadaver legs and 15 clinical cases, it has been possible to demonstrate adequate circulation to the skin of the lateral aspect of the lower leg from the septocutaneous branches of the peroneal artery alone. This finding has allowed the development of a new concept and technique to elevate the fibula as an osteoseptocutaneous flap for reconstruction which provides the following advantages: Elevation of the fibular osteoseptocutaneous unit is easy and fast. The cutaneous flap of the fibular osteoseptocutaneous unit can slide almost freely while attached to the paper-thin posterior crural septum without being tethered by a bulky muscle cuff, facilitating the setting of the fibular osteocutaneous flap when the bone and skin are widely separated. Intraoperatively, in a situation in which it is necessary to change from originally selected recipient vessels to ones more suitable, the thin posterior crural septum can be folded around the fibula allowing more flexibility in choice of recipient vessels. The fibular osteoseptocutaneous flap meets the criteria outlined for composite tissue reconstruction of defects of the extremities.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent