Results of nerve grafting in severe soft tissue injuries

Nerve grafting was performed in a series of patients, 81% of whom had associated severe soft tissue injuries in the area in which nerve grafting was done. Other factors that have been shown to have an adverse effect on nerve grafting results were analyzed and were not thought to be major factors influencing results. Results were worse than those of previous reports in which the initial injury was less severe. The initial soft tissue injury is very important in predicting how well a nerve graft will function. Nerve grafting is a valuable procedure even in the face of severe soft tissue injuries, since it alone can restore protective sensation.

Reconstruction of the facial nerve in acoustic neurinoma surgery. Juxtapontine-intratemporal nerve graft

Five cases of large acoustic neurinomas (diameter 2.5 cm) with involvement of the facial nerve in the tumour capsule are presented. The preoperative function of the facial nerve was normal. During surgery, in order to achieve a radical tumour removal, the facial nerve was severed juxtapontine. Reconstruction was performed at the same procedure using a 5-6 cm long sural nerve graft. Thus the central juxtapontine stump was joined to the peripheral stump in the facial nerve canal of the petrous bone. After six months, all five patients exhibited a well functioning mimic and a good eyelid function. At the one year control four patients had normal nerve function clinically and one patient still showed asymmetrical mimic.

The free vascularized sural nerve graft

The sural nerve was described as a new donor nerve of the free vascularized nerve graft in a fresh cadaver's dissection and in four clinical cases. The vascularized sural nerve is nourished by the cutaneous branch of the peroneal artery or the muscular perforating branch of the posterior tibial artery in our grafts. Compared to other vascularized nerve grafts, the sural nerve has many advantages: 1) A "two- or three-fold nerve graft" can be designed on itself without damage to the blood supply of the nerve, 2) survival of the nerve can be reasoned by the accompanying flap and the flap can close the skin defect simultaneously without additional vascular anastomosis, and 3) sensory loss at the donor site is negligible. The final extent of sensory recovery in our clinical cases could require several months, but a quickly advanced Tinel's sign suggested the technique's superiority.

Cross-face nerve grafting followed by free muscle transplantation in young patients with long-standing facial paralysis. Reanimation of the cheek and the angle of the mouth

For reanimation of the cheek in 8 young patients with long-standing facial palsy a method with cross-face nerve grafting followed by free muscle transplantation has been used. The sural nerve was used as nerve graft and placed in a subcutaneous tunnel across the face. In the normal cheek 3-4 fascicles of the nerve were anastomosed to facial nerve branches innervating muscles elevating the angle of the mouth. Four to 13 months later the extensor digitorum brevis muscle to the second toe or the palmaris longus was transplanted to the paralysed cheek. It was attached between the zygomatic arch and the angle of the mouth. The end of the nerve was sutured to the muscle after taking a biopsy. The follow-up period has been 7-30 months. At 7 months 6 patients had positive EMG, either on voluntary movement or on stimulation of the contralateral facial nerve. Three of them had also a slight movement in the cheek. Two patients are as yet only 7 months postoperative. In the remaining two cases, No. 2 and 4, there were no signs of reinnervation. At 18 months 4 out of 6 patients had a synchronous natural contraction in the cheek giving increased balance to the mouth. These patients had a positive EMG. In patients No. 2 and 4 there was neither innervation nor improvement. At 30 months there was additional improvement in two cases but as previously in patients No. 2 and 4 there was neither improvement nor signs of innervation of the muscle on the EMG. The other 4 patients have not reached this postoperative stage.(ABSTRACT TRUNCATED AT 250 WORDS)

Motor unit numbers, motor unit sizes and innervation of single muscle fibres in hyperinnervated adult mouse soleus muscle

The sural and the lateral plantar nerves were implanted simultaneously into the denervated soleus muscle of adult mice. Each of these nerves contained approximately the normal number of soleus motor axons. This procedure therefore allowed a study of how an initial excessive number of motor axons provided by two different, foreign nerves and terminating into the soleus muscle affected the final pattern of muscle innervation. In muscles examined two months or more after the implantation of the foreign nerves all muscle fibres were innervated. The fraction of the muscle innervated by either nerve varied widely from one preparation to another. However, all the motor axons which were implanted into the muscle appeared to make permanent synapses. Moreover, the distribution of motor unit sizes of each foreign nerve relative to the total number of muscle fibres innervated by that nerve was similar to the distribution of motor unit sizes in muscles cross-innervated by that nerve alone, although the absolute motor unit sizes were reduced. Estimated by intracellular recording, 20-30% of the muscle fibres were polyneuronally innervated. A similar fraction of teased muscle fibres stained for acetylcholinesterase had more than one end-plate.

[Sural nerve removal using a nerve stripper]

In 19 patients the sural nerve was removed for nerve grafting by a specially designed nerve stripper. This technique provides a safe and time-saving removal of the nerve in length up to 34 cm (depending on the length of the stripper used). From a single short incision at the level of the lateral malleolus the nerve is stripped proximally tearing some small branches of the distal nerve. The relatively blunt tip avoids inadvertent transection of the nerve at a lower level or dissection of the nerve at a point where branching occurs. Finally the nerve is cut by the divided cylinder at the tip of the stripper.

[Microsurgical method of transplantation of peripheral nerves]

The authors present the microsurgical technique of grafting thin cutaneous nerves at the site of peripheral nerve defect. The application of grafts in place of end-to-end suture makes possible elimination of nerve stretching at the time of suturing and at the time of rehabilitation. The use of cutaneous nerves makes possible good revascularization of grafts and their correct regeneration. The use of the microsurgical technique makes possible a good evaluation of the fascicular structure of nerve trunks, their adequate resection, and good adaptation of nerve stumps and grafts connecting the corresponding nerve fascicles. The use of the technique of nerve gluing with autologous plasma enables a stable connection of grafts and stumps to be obtained, with simultaneous elimination of foreign material (threads) from the area of connection.

Intercostal nerve transfer in brachial plexus injuries: an experimental study

Eighteen adult mongrel dogs underwent unilateral surgical disruption of the brachial plexus. Twelve animals (Group I) had as a second-stage procedure transfer of T4 and T5 intercostal nerves and their accompanying vascular bundles to the distal musculocutaneous nerve stump. Six animals (Group II) had restoration of musculocutaneous nerve continuity with conventional interpositional sural nerve cable grafts. Group I animals demonstrated significantly better electromyographic evidence of reinnervation and, comparing appearance and weight of operated and unoperated biceps muscles at the time of animal sacrifice, maintained greater gross weight and more normal overall appearance of muscle. Histologic study of muscle tissue showed no significant difference between the two groups whereas musculocutaneous nerve histology distal to all anastomoses revealed less fibrous tissue and a greater number of healthy-appearing axons in Group I. It is concluded that vascularized intercostal nerve transfer as performed in this study has theoretical advantages over conventional nonvascularized intercostal nerve transfer but additional investigation is required to make this determination. The superiority of vascularized intercostal nerve transfers over conventional interpositional sural nerve cable grafts has been demonstrated.

Electrophysiological study of nerve grafting

After using the sural nerve for cable grafting in three children with nerve defects of the upper limb, we conducted electrophysiological studies on the regeneration of the nerve. After nerve grafting, nerve regeneration was delayed as compared to that of the end-to-end suture, but muscle power recovered to 80% of normal. Electromyography showed isolated motor unit potentials with high amplitude and polyphasic waves at maximum voluntary contraction. The motor conduction velocity recovered to about 70% of the normal level, but the sensory conduction velocity was less than this. The motor conduction velocity was delayed in the graft site, which, for measurement purposes, included the two suture lines.

[Nerve transplantations in the upper extremity with autologous grafts]

The paper deals with the technique and indications of interfascicular nerve grafting. The operative technique and problems as well as new ideas are described. When the results published in this operative technique are compared, the following tendency is seen: some teams of microsurgeons have nearly the same excellent results after transplantation as after primary suture, while other teams have significantly more failures with transplantation. The problems with follow-up studies and the different methods of postoperative examination are discussed, as are the results of some of the teams.

Interfascicular nerve grafting

Interfascicular nerve grafting is a useful method to repair nerves with gaps. Good motor recovery can be obtained, and return of some degree of sensibility is possible. The procedure can be used to overcome small gaps that result from neglected sharp lacerations or after failure of primary repair, or large gaps that result from loss of nerve substance or traction lesions. Primary nerve repair should be done for acute lacerations. However, in old lacerations (more than three weeks old) and in nerve gaps of more than 2 cm in length, a functional recovery can still be expected after nerve grafting. The recovery of intrinsic function in median and ulnar nerve lesions above the elbow was poor. The intrinsic recovery in these patients will be reported when long-term follow-up results are available. Recovery of intrinsic function in median nerve grafts at the wrist level was much better than for lesions of the ulnar nerve at the same level. This may be related to the anatomy of the ulnar nerve in this area. By separating the dorsal cutaneous branch from the main trunk of the nerve, using it as a donor graft, better results are to be expected.

Electrophysiological evaluation of cross-face nerve graft in treatment of facial palsy

A cross-face autogenous single graft was performed in eight patients with facial palsy. Several electrophysiological techniques have been used in a follow-up study of one to three years' duration. Clinical results are extremely disappointing. The only recovery observed could not be ascribed to the graft. The investigations and the motor unit count in the facial muscles led to the conclusion that the surgical technique employed is a failure. The orbicularis oculi muscle in particular has no chance whatsoever of being satisfactorily reinnervated. Various reasons for this poor recovery are analysed: too small a number of properly grafted axons, syncinesis, muscle degeneration and poor myelination. These observations nevertheless suggest some experimental fields which may lead to improvements in the technique to a point where it may become clinically useful.

Light- and electron microscopic findings in the distal end of human cross-face sural nerve grafts

In five patients with long-standing facial palsy we have tried to improve the possibility of elevating the angle of the mouth by bringing regenerating axons from the facial nerve on the normal side through a sural nerve graft to a transplanted free muscle in the paralyzed cheek. In order to expect clinical improvement a sufficient number of axons must grow into and through the sural nerve graft, neuromuscular contacts must be formed, and the transplanted muscle must be vascularized and survive. In order to find out if axons had regenerated, light- and electronmicroscopic examinations of a biopsy from the tip of the sural nerve graft were carried out at the time of muscle transplantation. All the cases showed a very large number of unmyelinated axons located within the fascicles of the sural nerve graft. A considerable fraction of myelinated axons were, however, present particularly in biopsies removed 12-13 months after the nerve operation. There was also a marked increase in endoneurial collagen and at the very tip a neuroma was present. This investigation thus shows that regeneration of a substantial number of axons had occurred and that they had reached the zone which was surgically sutured to the transplanted muscle. One essential requirement for reinnervation of the transplanted muscle therefore exists in these patients, but the clinical outcome has not yet been evaluated due to the short follow-up period.

Implications of the failure of nerve resection and graft to cure chronic pain produced by nerve lesions

Seven patients had developed pain and abnormal sensitivity in the area supplied by a single nerve which had been injured. They were treated unsuccessfully for periods ranging from 3 to 108 months by conservative methods including neurolysis, local anaesthesia, sympathetic blocks, guanethidine, transcutaneous stimulation and analgesics. All then had the damaged nerve resected and in five cases a sural nerve graft was inserted to bridge the resected gap. The patients were then examined 20 to 72 months after the operation. In all seven cases pain and abnormal sensitivity of some intensity recurred in the same area and with the same qualitative characteristic as experienced before the operation. This operation should not be done in patients with this condition. Reasons are given to suggest that peripheral nerve damage induces changes in the central nervous system which are not reversed by treatment directed at the area of the original injury.

Experimental study of interfascicular grafts in the peroneal nerve of the rabbit

To elucidate the nerve, especially motor nerve, regeneration after interfascicular grafting, the method most often used clinically, the nerve grafting was performed on 40 adult rabbits. By resecting 2.0 cm of the right peroneal nerve, the sural nerve was made into 4 interfascicular grafts under a operating microscope. The cross section area of the grafts was about the same as that of peroneal nerve. Histological and evoked electromyographic observations were conducted on the maturation of regenerating nerves of up to 24 post-operative months, when the maturation would have been completed. The present histological and evoked electromyographic observations revealed that about 70% of nerve, especially motor nerve, recovery was attained after interfascicular grafts as compared with normal nerve. In the nerve regeneration after interfascicular grafts, several factors differing from the case of suture are involved, and these factors were considered from the experimental findings.

Bilateral microneurosurgical reconstruction of inferior alveolar nerves via autogenous sural nerve transplantation

Microneurosurgical operative techniques permit satisfactory restoration of sensation in many lesions of the inferior alveolar nerve. Therefore, restoration of the sensory deficit is becoming increasingly more important in the total functional rehabilitation of individuals with mandibular continuity defects involving transection of or permanent damage to the inferior alveolar nerve. This article reviews the case history of a young man who underwent bilateral osseous mandibular reconstruction and microneurosurgical reconstruction of his inferior alveolar nerves following severe maxillofacial trauma. A new technique for isolating the sural nerve is introduced to facilitate harvesting of the graft. Scanning electron microscopic examination of the resected proximal inferior alveolar nerve is recommended to determine the prognosis for regeneration across the proximal anastomosis and to decide whether secondary resection and reanastomosis of the distal anastomosis is indicated when anesthesia persists 9 to 12 months after initial transplantation of a long donor nerve.