Biomedical subjects
Publications and source records attributed to Y D Gu.
A rat model for free second toe replantation, free hallux-to-thumb transplantation, and combined free hallux-to-thumb transplantation and free second-toe-to-index transfer is described. Experimental devices, operative methods, and the keys to success are discussed.
The survival rate and elastic properties of the anterior abdominal skin flap in Sprague-Dawley rats were studied in three groups of animals. In group 1 where the flaps were supplied by a normal artery, arterial flaps (1A) had better survival rate and elastic properties than venous flaps (1B). In group 2, where the flaps were supplied by an artery with diminished perfusion pressure, the arterial flaps (2A) still had slightly better results than venous flaps (2B). However, in group 3 where the flaps were supplied by a vein, venous flaps (3B) had better results than arterial flaps (3A).
Cervical root nerve transfer from the contralateral side has been used for the treatment of brachial plexus root avulsion in 49 patients. Resection of C7 root from the healthy side has produced no long-term symptoms or signs. Nine patients with ten recipient nerves have been followed up for more than two years and seven have obtained a functional recovery. This operation offers a new approach for the treatment of brachial plexus root avulsion.
One hundred cases of toe transfer were subjected to histopathologic vessel examination. Results indicated that vascular injuries are crucially responsible for perioperative and postoperative crisis. A thorough resection of the abnormal vessel segment can prevent circulatory crisis and elevate the survival rate.
This study compared the functional results of contralateral C7 root neurotization with homolateral phrenic nerve transfer for repairing root avulsion of brachial plexus in rats. It was found that in the C7 nerve root group all the parameters of evoked muscle potential amplitude (EMPA), regenerating axon count, biceps weight and muscle fibre area, and muscular maximal tetanus tension were statistically superior (P < 0.05-0.01) to those in the phrenic nerve group; while there were no significant differences between these two groups in motor nerve latency regenerating axon area and persisting time of muscular maximal tetanus tension (P > 0.05). The reasons why C7 root neurotization is superior to phrenic nerve transfer were also discussed.
In order to evaluate the effects of various nerve transfers, experimental rat models simulating root avulsions of the brachial plexus were created, using four different types of nerve transfers. Four groups of 160 rats were randomly divided, and phrenic nerves, double intercostal nerves, accessory nerves, and single intercostal nerves were transferred. Electrophysiologic and histologic examinations and functional evaluations were performed at different postoperative intervals. Phrenic nerve transfer was found to be superior to the other types most likely on the basis of superior neural regeneration. A single phrenectomy in the rat was found to have no apparent effect on pulmonary function.
The effect of T-PA on experimental thrombosis in 116 rats was studied. Following intravenous administration of T-PA, plasma content of T-PA and its activity elevated in 2 minutes, at peak in 6 minutes, declined in 15 minutes and disappeared at 24 hours. In animals treated with T-PA, the endothelial areas, where thrombi occurred covered with fibrin and were ready for endothelialization, as was shown under electron microscope. It was proved that small dose of T-PA (1/3 mg/100 g) could work as a thrombolytic agent, not evoking hemorrhage resulting in death of the animals.
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The authors had designed cervical root nerve transfer from the contralateral normal side for the treatment of brachial plexus root avulsions in August 1986. Since then, the operation was performed in 50 cases. Follow-up studies showed that resection of C-7 root from the healthy side produced no long-term ill effect except numbness and pain of the fingers and weakness of gripping strength shortly after the procedure. In 10 recipient nerves of 9 cases with follow-ups of more than 2 years, satisfactory results were seen in 7. This is a new approach for the treatment of persistent cases of brachial plexus avulsion.
Phrenic nerve transfer was performed in 164 patients with root avulsion of the brachial plexus. The methods of operation consisted of phrenic nerve transfer to and anastomosis with the musculocutaneous nerve, the phrenic nerve bridging to the musculocutaneous nerve, phrenic nerve anastomosis with or bridging to the median nerve, and phrenic nerve anastomosis with other nerves. Follow-up of 65 patients for more than 2 years showed an effective rate of 84.6%. The result indicated that this operation has no deleterious effects on respiration, and the surgical effects are related to severity of injury, duration, mode of operation and patient's age.
Twenty-one patients, under 6 years of age, with root avulsion of the brachial plexus were treated from 1975 to 1987. Among them, 9 had root avulsion of the upper trunk, 2 root avulsion of the lower trunk with middle trunk broken, and 10 root avulsion of the whole brachial plexus. Follow-up of 16 patients showed excellent results in 2 patients, good in 11, fair in 1 and poor in 2. It is suggested that good results can be obtained if multi-paired nerve transfer is adopted in treatment. We conclude that owing to anatomical and physiological characteristics of the respiratory system in children, it is harmful to perform phrenic nerve transfer concomitantly with intercostal nerve transfer. Advisably, two-stage operation is required, otherwise dyspnea and pneumonia are liable to occur. In addition, the time of the operation could be extended to 4-5 years after injury in children, but best results are obtained if the operation is performed within 1 year.
A new embedding method in tendon suture was designed for interembedding of tendon ends to obtain interlock and strengthen antitension strength. Experiments showed that the embedding method might result in greater antitension strength than the conventional end-to-end method (Bunnell's method) or weaving method. Statistically, difference was significant. Dynamic studies on tendon healing showed that a prominent reaction of surrounding tissues occurred in 3 to 5 days after operation. In this period the antitension strength is likely to decrease and be broken with a rate of 28.1% in Bunnell's method, 5.25% in weaving method and 0% in embedding method. Clinically, the embedding method has been used in 125 cases of tendon-broken repair in which a 87.8% of good and excellent effect was resulted.
We report a series of 164 patients who underwent phrenic neurotization to elements of the brachial plexus with root avulsion injuries. Recipient nerves included musculocutaneous nerve in 125 patients (78 direct neurotizations and 48 with intervening autograft), median nerve in 10 patients, and a variety of other nerves in 28 patients. Sixty-five patients presented a follow-up period of 2 or more years. Of this group, 55 patients (84.6%) achieved a recovery of M-3 or better. We observed no long-term deleterious effects on respiratory function.
On the basis of experience with 226 patients undergoing free toe transfer for reconstruction of the thumb and fingers, circulatory crises during and after surgery are analyzed and classified according to the time of crisis occurrence. Prompt re-exploration is indicated when the crisis occurs within 24 hr postoperative. Crises occurring 48 hr and more postoperative are usually due to vasospasm, and antispasmodic therapy should be instituted. Surgical intervention in these later cases may prove fruitless.
In 1985, we applied an arterialized vein stem free flap in 4 cases with success in 3. In making this flap the superficial vein with the covered skin of the limb was used. In operation the flap was inverted and the 2 ends of the vein stem were anastomosed with the artery of the recipient area. Rapid arterial blood flow not only provided blood supply to the flap, but through the "venous network shunt" and "tidal pressure difference of artery" maintained blood circulation of the flap. The details of technique and the changes of blood circulation after flap transfer are described, as are indications advantages and mechanism of blood circulation of the flap, and factors affecting the circulation.
A new combined measure of nerve transfer, including antebrachial medial cutaneous nerve, and free musculocutaneous flap transfer was applied to the treatment of irreversible avulsion of the brachial plexus. 12 patients underwent this operation for restoring elbow and finger flexion. Good result was obtained in 71% for elbow and 60% for finger flexion restoration. The definition of irreversible avulsion and the methods, key points and value of the operation are described and discussed in detail.
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164 patients with injury of root avulsion of the brachial plexus was treated by way of ipsilateral phrenic nerve transfer through a time period from 1970 to 1987. The among 65 cases that had been followed up for 2-13.5 years on average, 55 cases (84.6%) regained muscular strength of 30 or more. None of the patients had any subjective feeling or objective signs of respiratory disturbance, although post- operative machinery tests and laboratory surveys had detected some impairment of pulmonary function, which gradually improved with lapse of time. In conclusion age of the patients, length of the time delayed for surgery, severity of the nerve injury and the operative choice are the determining factors of the final results.