Expression of choline acetyltransferase within spinal motoneurons following brachial plexus avulsion.

Avulsion of the brachial plexus is considered the most severe injury of the peripheral nerve. The present study provides a description of the response of ChAT within the ventral horn of the rat cervical spinal cord following avulsion of the brachial plexus. The result demonstrates that the intensity of immunoreactivity of ChAT positive neurons and neuropil background increases in the first 3 days following avulsion and then decreases. The number of ChAT-positive motorneurons in the ventral horn in the lesion side is 84.4% compared to the normal side during the first 3 days post-avulsion, at 7 days the number of ventral horn neurons drops to 64.4% and at 21 days post-avulsion it becomes 44.1%. In the sixth week post-avulsion, only 24.8% of the ventral horn neurons still persist.

Sensations from surgically transferred glabrous skin; central versus peripheral factors.

In reinnervated skin transferred from the foot to the hand, sensory thresholds approach normal values--an observation not predicted by the theoretical relationship between innervation density and tactile acuity. Therefore, we suggest that innervation density is not the major factor determining tactile acuity. Rather, the hand region of the central somesthetic map may be specialized to provide a calibre of function unavailable to other regions.

Sensory mapping.

The primary aim in reconstructive surgery of the upper extremity is to provide tactile gnosis to sensory depleted areas. It is essential for restoration of function and successful rehabilitation of the injured hand. Neurovascular free flaps may provide the answer to this catastrophic problem and transform a useless appendage into a functional gripping hand. Sensory mapping techniques can greatly assist the surgeon in precisely defining new donor sites for these transfers. Cutaneous sensibility, cutaneous sensation, and hand function are subjects of great complexity. Much more investigative and clinical work is needed in this challenging field to improve our evaluation of the sensory injury to the hand and to provide new avenues for restoring functional sensibility in the upper extremity.

The anatomy of free vascularized nerve grafts.

Nerve grafting has made advances in the last 100 years. One of the most significant of these was realizing the importance of adequate blood supply for successful nerve grafting. The vascular anatomy of the six potential vascularized donor nerves we have reviewed may prove to be extremely useful in reconstructing proximal nerve lesions, large nerve defects, and compromised recipient beds.

Strategies in the microsurgical management of brachial plexus injuries.

The authors' experience in the management of brachial plexus injuries over three periods of evolution is presented. Developments in microsurgery have expanded the strategies in brachial plexus management, and these are discussed in full.

Carbonic anhydrase histochemistry. A potential diagnostic method for peripheral nerve repair.

Many large-diameter myelinated axons in spinal dorsal roots contain carbonic anhydrase activity, whereas few small-diameter ventral root axons stain for this enzyme. This differential localization of carbonic anhydrase in sensory and motor nerve fibers is indicative of the potential of carbonic anhydrase histochemistry to provide a convenient method for identifying predominantly motor or sensory fascicles in cut ends of peripheral nerves, thereby facilitating coaptation of fascicles in peripheral nerve repair.

Pectoralis minor: a unique muscle for correction of facial palsy.

The author introduced this muscle for the first time almost a decade ago, and this is the first extensive description of the intricate microanatomy of this complex but unique microneurovascular muscle unit. Advantages and disadvantages and indications and contraindications for its use in facial paralysis are presented in detail from an extensive clinical experience of almost 50 such microneurovascular transfers. Pitfalls that the reconstructive microsurgeon should beware and strengths in using this muscle for facial palsy are highlighted. The detailed operative approach is presented, with promise of undetectable scars and minimal functional loss. The strategies for how to inset this muscle unit in the new recipient site are given, along with the thought processes involved in selecting the actual sites of anchoring the muscle to reproduce a mirror image of the contralateral normal face. Finally, an exemplary clinical case demonstrating the use of the pectoralis minor muscle for both eye and lower face reanimation is presented in detail, demonstrating the dual nerve supply and the resulting independent eye and smile movements with total lack of mass action and/or synkinesis. Restorations of eye blink and of a symmetrical and coordinated smile are the frequent rewards of using this unique muscle for the correction of facial palsy.

Functional aspects of reinnervation of free skin grafts.

The reinnervation of full-thickness skin grafts has been studied with single mechanosensory unit recordings. Shortly after transplantation of the skin, most of the incoming fibers conduct impulses at slow velocities, which correspond to the unmyelinated group of sensory fibers. The older skin grafts demonstrated an increasing amount of myelinization as shown by the shorter latencies and faster conduction velocities. However, the critical balance between myelinated and unmyelinated fibers that characterizes normal cutaneous innervation was still disrupted in the grafted groups at 15 months. Whether this imbalance persists indefinitely is uncertain. The introduction of electrophysiological techniques into the study of peripheral nerve injuries, in experimental animals and in man, has given us some insight into the unexplored nature of this field of experimental and clinical investigation. The future promises to be exciting.

Epineurial vs. perineurial repair.

Previous work concerning the efficacy of different types of nerve repair has been reviewed. We describe a model in which epineurial and perineurial suture techniques were studied by quantitative ultramicroscopy and electrophysiology. In this model, we believe suture of the perineurium was shown to have a slight advantage over suture of the epineurium. Microscopic control and fascicular alignment are advocated to increase the percentage of axons growing into the distal stump and the periphery. The model described should lend itself to the study of other traumatic peripheral neuropathies.

The nerve gap: suture under tension vs. graft.

Conduction velocities and amplitudes of evoked responses were used in experimental models to compare reinnervation through nerve gaps sutured under tension or bridged with nerve grafts. The best results were obtained when end-to-end suture was done without tension. Regeneration through mildly stretched nerve repairs was equivalent to applying a properly tailored graft. Minimal axonal activity was exhibited by severely stretched repair sites.

Analysis of 100 cases of free-muscle transplantation for facial paralysis.

Free-muscle transplantation is the treatment of choice for long-standing facial paralysis. It enables the reconstructive surgeon to restore facial movement and some emotional animation. Despite all technical innovations and 20 years of experience with free-muscle transplantation, the aesthetic and functional outcomes of the surgery are still unpredictable. The present report reviews 100 free-muscle transplantations to the face by a single surgeon and analyzes various preoperative, intraoperative, and postoperative factors in relation to the functional recovery of the muscle transplants. These factors were demographic variables such as age, gender, and etiology as well as intraoperative variables such as choice of muscles, number of nerve coaptations, and ischemia time of the muscle. Additionally, four independent raters not involved in the care of these patients rated standardized preoperative and postoperative videos and judged the functional and aesthetic outcomes. From 1981 to 1993, 93 patients with facial paralysis underwent free-muscle transplantation. A total of 100 muscles were transplanted, since 7 patients received two muscle transplants. There were 33 male and 60 female patients ranging in age from 3 to 57 years, with an average of 22.2 +/- 14.9 years. The gracilis muscle was used in 63 cases of free-muscle transplantation, while the pectoralis minor was used in 34 cases. In 2 patients a segment of the rectus abdominis was transferred, and in 1 patient a small segment of the latissimus dorsi was transferred. In 89 patients the onset of muscle function was reported. The range was from 6 to 48 weeks postoperatively. The average was 21.6 +/- 9.14 weeks after muscle transplantation. The correlations showed a trend to earlier onset of function and higher aesthetic rating in young female patients. The intraoperative ischemia of the free muscle did not correlate with the onset of muscle function. Using a five-step scale of judgments, a higher postoperative rating was seen in 94 percent of the patients, and 80 percent of all patients achieved a moderate or better result.

The surgical treatment of brachial plexus injuries in adults.

Posttraumatic brachial plexus palsy is a severe injury primarily affecting young individuals at the prime of their life. The devastating neurological dysfunction inflicted in those patients is usually lifelong and creates significant socioeconomic issues. During the past 30 years, the surgical repair of these injuries has become increasingly feasible. At many centers around the world, leading surgeons have introduced new microsurgical techniques and reported a variety of different philosophies for the reconstruction of the plexus. Microneurolysis, nerve grafting, recruitment of intraplexus and extraplexus donors, and local and free-muscle transfers are used to achieve optimal outcomes. However, there is yet no consensus on the priorities and final goals of reconstruction among the various centers.

Neurovascular free flaps. A preliminary report.

An experimental, anatomical, and clinical study has confirmed the feasibility of free neurovascular flaps. The interrelationship between the cutaneous vascular and neural supply has been defined and demonstrated electrophysiologically, both in man and in experimental animals. A potential donor site in man has been explored. Free neurovascular flap transfers by microneurovascular anastomoses are technically feasible. Clinical success will occur with the identification of suitable donor sites.

Sensory skin flaps for coverage of pressure sores in paraplegic patients. A preliminary report.

Sensory skin flaps represent a possible solution for the paraplegic who has the problem of recurrent pressure sores. An intercostal neurovascular island flap has been used in 3 cases to provide coverage for sacral ulcers. Sensation was retained to a variable degree in both adults and children. An attempt at coverage of an ischial ulcer with an intercostal neurovascular free flap is also reported. The practical and theoretical aspects of these procedures are discussed.

Efficacy of intervention strategies in a brachial plexus global avulsion model in the rat.

The treatment of brachial plexus avulsion lesions invariably involves the use of neurotization procedures. Although some of these therapeutic strategies have been used for the past 20 years to restore selective function to the injured extremity, the individual efficacy of these nerve transfers has not been measured objectively, thereby rendering the prognostication of outcomes for these techniques a major problem. Using a true global avulsion model, the present study compares outcomes of the various neurotization procedures for the first time. The strength of this experimental model is that each nerve transfer tested leads to a common terminal pathway involving a single target-namely, the biceps muscle. Thus, quantitative measurements of biceps restoration will provide strong clues to the power of axonal regrowth of that particular motor pool. This study also introduces the Terzis grooming test, a modified behavioral test that can be quantified and that can provide an overall functional scale in the assessment of outcome. Thirty-five Sprague-Dawley rats were divided into seven groups, with each group testing a different motor donor for biceps reinnervation. The ipsilateral brachial plexus was globally avulsed in all animals, with the exception of the ipsilateral C7 group, and the respective motor donor coapted in an end-to-end fashion to the musculocutaneous nerve. Functional outcomes were measured by the Terzis grooming test, electromyography, biceps muscle force measurements, motor end plate counts, and quantitative axonal morphometry. The values of the different parameters were expressed as a standard score on a common scale. The relative standings of each group on each parameter were compared. Superior outcome was observed in the phrenic, the hypoglossal, and the ipsilateral C7 groups.

Outcomes of brachial plexus reconstruction in 204 patients with devastating paralysis.

Thus far, devastating injuries of the adult brachial plexus have had a poor prognosis. This article presents the possible outcomes of aggressive microsurgical reconstruction in the largest series of patients in North America to date. It should change the pessimistic outlook that has surrounded these lesions. In this study, the outcomes of surgery were analyzed in relation to the type and level of injury, the age of the patient, and the denervation time; stronger donors for neurotization in relation to the various targets were delineated. The results were analyzed in 204 patients with adequate follow-up from a total of 263 patients who were operated on between 1978 and 1996. The mean age of the patients was 25.9 years, and the injuries were caused by high-velocity motor accidents involving avulsion in 55 percent of the patients. Nerve reconstruction included 577 nerve repairs (140 direct neurotizations and 437 cases of nerve grafting). Microneurolysis was performed in 89 cases. Vascularized nerve grafts were used in 120 repairs. Muscle transfers (29 pedicled and 78 free) were used to enhance function. The results were good or excellent in 75 percent of suprascapular nerve reconstructions, 40 percent of deltoid reconstructions, 48 percent of biceps reconstructions, 30 percent of triceps reconstructions, 35 percent of finger-flexion reconstructions, and 15 percent of finger-extension reconstructions. The majority of the patients had protective sensation and pain relief postoperatively.

Reflex sympathetic dystrophy syndrome: consensus report of an ad hoc committee of the American Association for Hand Surgery on the definition of reflex sympathetic dystrophy syndrome.

This report proposes that reflex sympathetic dystrophy be defined as a pain syndrome in which the pain is accompanied by loss of function and evidence of autonomic dysfunction. In the clinical setting, this diagnosis is usually associated with other anatomic and psychological diagnoses and may be associated with a variety of systemic illnesses and medicolegal factors. All components should be assessed before a treatment plan is established. Priorities should go to emergency care, acute injuries, and systemic illness, psychiatric problems, and chronic anatomic problems, in that order. Early, accurate diagnosis improves prognosis.

Vascularized nerve grafts. A review.

The attempts to reconstruct a transected trunk nerve with a free nerve graft of equal diameter have been hindered by the problem of delayed establishment of blood supply to the nerve graft and development eventually of central necrosis and finally failure of nerve regeneration. The transfer of a nerve graft which maintains its blood supply through its vascular pedicle that is microsurgically anastomosed to the recipient site vessels, provided the reconstructive microsurgeon with a new perspective to the clinical problem. A vascularized nerve graft diminishes endoneurial scarring by maintaining the Schwann cell population and decreasing fibroblast infiltration providing, thus, an optimal nutritional environment that results in an increased rate of axonal regeneration.

Reinnervation of peripheral nerve grafts by spinal cord fibres tested by transcranial brain stimulation.

A scheme for surgery in patients with avulsed roots is represented by a rat model whose left sciatic nerve was grafted upon the right sciatic nerve, the proximal end of the graft being introduced into the spinal cord white matter. Transcranial stimulation, EMG recording, HRP and histological studies proved that the communication between the brain and the denervated muscles may be reestablished via the motoneurons, through the graft, bypassing the motor roots. Behavioral techniques were developed and will be tested in the future. The possibility of using neurotrophic drugs will be considered.

Management of obstetric brachial plexus palsy.

OBPP is a disease with deleterious medical, psychological, and socioeconomic sequelae for the patient and his or her family. The majority of patients show acceptable spontaneous recovery with nonoperative management, which includes aggressive physical rehabilitation and electrical stimulation. There are patients with guarded prognosis, however, who have no chance of recovery unless they undergo early aggressive surgical reconstruction of the injured brachial plexus. It is of great importance to diagnose the injury type as early as possible, especially if there is minimal recovery in the early weeks of follow-up. This allows timely reconstruction to take place, earlier than 3 months for global palsy cases and at 3 months in Erb's type lesions, for best functional results.