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Biomedical subjects

D C Chuang

Publications and source records attributed to D C Chuang.

8 recordsLinked to original sources

Intercostal nerve transfer of the musculocutaneous nerve in avulsed brachial plexus injuries: evaluation of 66 patients.

Intercostal nerve transfer is a well-established and effective technique for irreparable avulsed brachial plexus injuries. Between 1987 and 1989, 66 patients with brachial plexus injuries were treated by means of intercostal nerve transfer to the musculocutaneous nerve, with or without nerve grafts to obtain elbow flexion. The results were evaluated. Five clinical signs--(1) induction of chest pain by squeezing of biceps, (2) proximal biceps contraction, (3) distal biceps contraction, (4) active elbow flexion against gravity, and (5) active elbow flexion against weight--were identified and used as a guide for functional recovery. The overall success rate with motor function of grade 4 or more was 67%. The motor results were better in 1989 (81%) because of greater familiarity with the anatomy and improved surgical technique. The important factors in obtaining a good result are (1) early exploration (less than 5 months after trauma), (2) use of three intercostal nerves, (3) mixed nerve-to-mixed nerve coaptation, (4) nerve repair without grafts and under no tension, and (5) shoulder stability.

Adolescent

Compound functioning free muscle flap transplantation (lateral half of soleus, fibula, and skin flap).

The functioning free-muscle transfer is a microneurovascular technique that has proven effective for patients who have a major muscle or muscle group loss for which no other less complicated procedures are available. A new functioning muscle (lateral half of the soleus) transfer was used for forearm reconstruction. This functioning muscle can be transferred alone, or it can be used with overlying skin or nearby fibular bone or both. It was used in a selective complicated case in which not only were major functional muscles lost, but a bone deficiency and skin loss also were seen. The operation was done in one stage with the composite flap (muscle plus bone plus skin). The recovered transferred muscle provided adequate strength and excursion for a functional hand and forearm.

Adolescent

Technique of foot lengthening and shaping with free vascularized iliac osteocutaneous flap.

The iliac osteocutaneous flap has been used widely to replace bony defects of the mandible and the extremities. We report a further application of this flap in foot reconstruction. The iliac osteocutaneous flap proved to be of value to augment both soft tissue and bone in a transmetatarsally amputated foot. This resulted in satisfactory function and an appealing cosmetic result, allowing the patient to wear normal shoes. Flap design and secondary contouring procedures are described for the success of this reconstruction.

Adult

Root reconstruction for bladder reinnervation: an experimental study in rats.

Nerve transfer (or nerve crossover) is a well established technique for achieving reinnervation of a valuable sensory or motor territory by reconnection using a functional nerve of lesser value. Patients with lower spinal cord lesions causing neurogenic bladder dysfunction could theoretically benefit from such an approach for return of useful micturition. Based on the known anatomical details of the spinal nerve, a new reconstructive method was created to provide intradural ventral root transfer for pure motor-to-motor reinnervation and extradural postganglionic spinal nerve transfer for pure sensory-to-sensory reinnervation. Experimental studies in rats were performed, demonstrating the feasibility of this approach. A modified method is further suggested that would use nerve grafts for extradural approaches to pure motor and sensory transfers, without the need for extensive laminectomy and dura opening. This proposed approach is anticipated to minimize the associated morbidity and mortality with such spinal nerve reconstruction.

Animals

Second toe wrap-around flap.

The microsurgical second toe wrap-around technique is an ideal treatment option for reconstruction of the distal half of the finger with circumferential loss of skin and nail associated with an uninjured proximal interphalangeal joint and an intact insertion of the flexor digitorum superficialis tendon. Follow-up of 13 flaps in 10 patients from 1986 to 1989 demonstrates rapid and adequate functional recovery as well as satisfactory aesthetic appearance in all patients.

Adolescent

"Smile" reconstruction in facial paralysis.

Reanimation of the face following facial nerve paralysis, especially the socially important smile, presents a complex surgical challenge requiring an individualized approach. Both neural and non-neural operative procedures have been used in an attempt to achieve the goal of a symmetrical synchronous smiling expression. A retrospective review of the results of both neural and nonneural methods was made to determine the relative efficacy of various methods. Of the neural techniques, early direct nerve repair primarily consistently achieved the best functional recovery. Double nerve grafts were found to be superior to a single nerve graft in nerve severance with a nerve gap at the facial nerve trunk bifurcation in delayed cases. In long-standing cases, ipsilateral or cross-face nerve grafting followed by functioning muscle transfer gives the most acceptable synchronous smile. Although cross-face nerve graft only, hypoglossal facial transfer, or non-neural techniques such as temporal muscle transfer achieved restoration of the smile, their inconsistent results and asynchronous action still limited the patient's confidence in social interactions.

Facial Expression

Groin flap design and versatility.

The groin flap is a reliable and well-established reconstructive option for pedicled or free-tissue transfer. Concern regarding its variable vascular origin and caliber has limited its use. To overcome this, a simplified guideline based on the transverse diameter of the patient's index and long fingers at the distal interphalangeal level has been developed. Thus "rule of two finger widths" positions the origin of the vascular pedicle from the femoral vessels two finger widths below the inguinal ligament, the upper flap border two finger widths above the inguinal ligament, the lower flap border two finger widths below the vascular origin, and both parallel to the flap axis, which lies along a line from the vascular origin to the anterosuperior iliac spine. This new groin flap design provides the necessary guidelines for vascular identification, accommodates pediatric and adult stature, and ensures primary donor-site closure if flap dimensions are within the prescribed boundaries. In addition, a new sartorius-cutaneous groin flap is presented. This combines the cutaneous groin flap with the proximal sartorius muscle (up to 15 cm), which is supplied by the deep vessels of the superficial circumflex iliac system. The sartorius-cutaneous groin flap further emphasizes the concept of single-pedicle compound or combined flaps and additionally enhances the extensive reconstructive versatility of previously described groin flaps. Over 200 pedicled and free groin flaps have been performed according to the "rule of two finger widths" over the past 5 years. There have been no complications related to flap design, such as difficulty with flap elevation, marginal necrosis, or donor-site closure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Experience of 73 free groin flaps.

The free groin flap has gradually lost its popularity due to the disadvantages relating to the pedicle and the plethora of new donor sites. The purpose of this article is to re-evaluate this time-honoured free flap and to demonstrate its reliability and versatility through a review of 73 free groin flaps performed between 1985 and 1990. 7% of free transfers (total 1096 cases) in our institution were free groin flaps. The complication rate was 8% (three complete failures and three partial failures). This result is acceptable and not so high as other reports have described. The artery discrepancy is the main cause of the complication rate. Two special techniques to gain additional diameter of vessel size to overcome the pedicle disadvantages are stressed. The groin flap has proved to be useful and still deserves consideration in reconstructive procedures.

Adolescent