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This is a description of the development of an animal model for intercostal nerve transfer and saphenous nerve grafting to lumbar nerve roots in the dog. Further, the technical feasibility of intercostal nerve transfer and autogenous sural nerve grafting to the lumbar and sacral nerve roots in the adult and infant human cadaaver is demonstrated graphically.
These are the neuropathologic findings in dogs 8-11 months after a unilateral intercostal nerve transfer and anastomosis to a lumbar nerve root were performed. This is a follow-up study of a procedure that was initially carried out in the adult and infant human cadaver and subsequently in an animal model by Malik and Buhr, as reported in this issue of Spine. At the time of sacrifice, the animals in this study had lost the limp that they had postoperatively. The results demonstrate the viability of the intercostal nerve transfer and its anastomosis to the lumbar motor root. There was supplied by a lumbar nerve root that had been operated upon, but the basis of this was not definitely established.
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.
The anterior interosseous nerve was transferred to the recurrent branch of the median nerve and the deep branch of the ulnar nerve respectively to restore the function of the intrinsic hand muscles. Twelve Rhesus monkeys were used with 24 nerves for transference and 24 for direct suturing. Gross, histological, and ultrastructural observations, electrophysiological evaluation and computer-imaging analysis system were employed to assess the nerve regeneration process in 1,3,6, and 12 months after operation. The results showed that the rate of maturity and the number of regenerating nerves in the distal segment approached the normal level and the passing rate of the myelinated axons reached to 156.16 +/- 14.45% 12 months after operation. According to the histological findings and the recovery of the intrinsic hand muscle function, reinnervation in the transferred nerves occurred 1 to 3 months earlier than that in the directly sutured ones.
There are a variety of methods for treating unilateral vocal cord paralysis, but to date there are few objective studies that evaluate the functional results of nerve transfer from the ansa cervicalis. Six dogs underwent unilateral recurrent laryngeal nerve section with immediate reanastamosis to the sternothyroid branch of the ansa cervicalis. After 5 to 6 months, measurements of vocal efficiency and acoustic parameters, videolaryngoscopy, videostroboscopy, and evoked electromyography were performed. Identical measurements were made in eight control dogs during normal electrically induced phonation and a simulated unilateral recurrent laryngeal nerve paralysis. Histologic analysis of both vocalis muscles, recurrent laryngeal nerves, ansa cervicalis, and the ansa-recurrent laryngeal nerve anastamosis site was performed. Evidence of reinnervation was found in all of the animals that underwent nerve transfer. The vocal efficiency and acoustic quality after ansa cervicalis nerve transfer were dependent on the degree of electrical stimulation from the transferred nerve to the reinnervated cord during phonation. In the absence of electrical stimulation to the nerve transfer, physiologic vocal cord motion could not be elicited from the reinnervated cord.
Brachial plexus palsy due to traction injury, especially spinal nerve-root avulsion, represents a severe handicap for the patient. Despite recent progress in diagnosis and microsurgical repair, the prognosis in such cases remains unfavorable. Nerve transfer is the only possibility for repair in cases of spinal nerve-root avulsion. This technique was analyzed in 37 patients with 64 reinnervation procedures of the musculocutaneous and/or axillary nerve using upper intercostal, spinal accessory, and regional nerves as donors. The most favorable results, with an 83.8% overall rate of useful functional recovery, were obtained in patients with upper brachial plexus palsy in which regional donor nerves, such as the medial pectoral, thoracodorsal, long thoracic, and subscapular nerves, had been used. The overall rates of recovery for the spinal accessory and upper intercostal nerves were 64.3% and 55.5%, respectively, which are significantly lower. The authors evaluate the results of nerve transfer and analyze different donor nerves as factors influencing the prognosis of surgical repair.
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.
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.
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.
Anastomosis of the superficial radial nerve, the dorsal cutaneous branch of the ulnar nerve, or both to the distal cut end of a widely resected median nerve in monkeys was followed by successful sensory reinnervation of the thumb, index finger, and long finger within thiry-five to forty weeks. Success was ascertained by the presence of an intact anastomosis as observed grossly without any evidence of spontaneous regeneration of the median nerve. Reinnervation was confirmed by histological and histochemical reactions observed in the Meissner's corpuscles in the skin innervated by the median nerve. The demonstration of nerve fiber and the presence of normal specific and non-specific cholinesterase reactions exhibited by the Meissner's corpuscles in the cholinesterase preparations were considered the histological criteria for successful reinnervation. These histological and histochemical observations may explain the reported functional sensory recovery in clinical cases when similar nerve transfers were done.
Surgical rehabilitation of the paralyzed larynx is currently performed by Teflon injection, thyroplasty, and reinnervation techniques. Proponents of the two newer techniques maintain that they are preferred to Teflon injection because superior phonatory quality is achievable. This paper was written in an attempt to dissect the issues regarding this question. Teflon remains the quickest and least expensive procedure, but further experience with stroboscopic and other voice analyses reveals that the other procedures demonstrate some superiority in phonatory quality over Teflon. In this author's hands, the nerve transfer offers the best opportunity to achieve a normal phonatory voice. In addition, it is the only one of the three procedures that leaves the vocal cord entirely undisturbed--important in the event one of the other two procedures becomes necessary.
There is a lack of agreement regarding the potential for peripheral nerve cells with short axons to regenerate and innervate the terminal end organs of nerve cells with long axons. We designed a study to evaluate experimentally the possibility of neurons to reconstitute much longer axonal segments. Twenty Wistar rats were used. The brachial plexus was isolated and the radial nerve transected immediately after its origin. The proximal end of the axillary nerve (previously cut) then was coapted tot he distal stump of the radial nerve. In 10 other rats, the cut radial nerve was simply recoapted to itself without involvement of the axillary nerve; these animals served as controls. Finally, in 10 rats, nerves were cut without repair to evaluate the degenerative changes. After 90 days, the distal part of the radial nerve was examined by light microscopy, calculating the number and area of regenerated axons. We also checked the motor end-plates of reinnervated muscles. In the nerve-transferred group, good axonal regeneration with good reinnervation of the muscles was seen. In this way, we have experimentally demonstrated a plasticity of regeneration in peripheral nerves. This suggests that the surgeon may use nerves connected to proximal muscles to neurotize avulsed nerves of distal muscles.
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.
The rate of entry of albumin into the endoneurial space and its content within that compartment during development were investigated by measuring the permeability coefficient-surface area product to 125I-albumin (PSA) of the blood-nerve interface (BNI), endoneurial residual plasma volume (Vp), blood-nerve interface index to albumin, and endoneurial water content in sciatic nerves of rats ranging in age from 1 to 24 weeks. There was a 30-fold reduction in PSA and a 4-fold decrease in Vp from 2 to 24 weeks, indicating that the endoneurial capillaries and perineurium become less permeable during development. On the other hand, the Alb-BNI index was relatively small at 1 week, increased to a peak value around 6-8 weeks, and then decreased to adult values by 13 weeks. The smaller Alb-BNI index in the neonatal period is consistent with endoneurial albumin being cleared across a permeable perineurium by epineurial lymphatics. Subsequently, as the perineurium becomes less permeable, endoneurial albumin content increases. It then decreases as the endoneurial capillary permeability also decreases. Additionally, metabolic clearance of albumin, especially during the first 2-3 weeks, by axons and glia to meet the nutritive requirements of rapid axonal growth and myelination could be partly responsible for a lower Alb-BNI index. It is suggested that in the developing nerve, the combination of epineurial lymphatics and a relatively permeable perineurium, together with axonal and glial uptake and protein catabolism aid in the clearance of plasma-derived osmolytes from the endoneurial space, and thus prevent the elevation of endoneurial hydrostatic pressure and onset of oedema that would have been seen in an adult nerve with a comparably permeable BNI.
This paper describes the application of re-routing neighbouring vessels and nerves to restore circulation and sensation in cases where there are vessel and nerve loss. The sources of donor vessels and nerves are discussed. Its use in salvaging the degloved and avulsed digits and skin in the hand is established. The extension of this technique in restoring sensation in paraplegic patients is promising.
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.
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Nerve growth factor (NGF) interacts with both high affinity (Kd = 10(-10)-10(-11)M) and low affinity (Kd = 10(-8)-10(-9)M) receptors; the binding of NGF to the high affinity receptor is correlated with biological actions of NGF. To determine whether a single NGF binding protein is common to both forms of the receptor, a full-length receptor cDNA was introduced in the NR18 cell line, an NGF receptor-deficient variant of the PC12 pheochromocytoma cell line. The transformant displayed (i) both high and low affinity receptors detectable by receptor binding; (ii) an affinity cross-linking pattern with 125I-labeled NGF similar to that of the parent PC12 cell line; and (iii) biological responsiveness to NGF as assayed by induction of c-fos transcription. These findings support the hypothesis that a single binding protein is common to both forms of the NGF receptor and suggest that an additional protein is required to produce the high affinity form of the NGF receptor.