Retrograde peripheral nerve regeneration from sensory to motor pathways in rats: a new experimental concept in nerve repair

BACKGROUND

The polarity of nerve grafts does not interfere with axon growth. Our goal was to investigate whether axons can regenerate in a retrograde fashion within sensory pathways and then extend into motor pathways, leading to muscle reinnervation.

METHODS

Fifty-four rats were randomized into four groups. In Group 1, the ulnar nerve was connected end-to-end to the superficial radial nerve after neurectomy of the radial nerve in the axilla. In Group 2, the ulnar nerve was connected end-to-end to the radial nerve distal to the humerus; the radial nerve then was divided in the axilla. In Group 3, the radial nerve was divided in the axilla, but no nerve reconstruction was performed. In Group 4, the radial nerve was crushed in the axilla. Over 6 months, we behaviorally assessed the recovery of toe spread in the right operated-upon forepaw by lifting the rat by its tail and lowering it onto a flat surface. Six months after surgery, rats underwent reoperation, nerve transfers were tested electrophysiologically, and the posterior interosseous nerve (PIN) was removed for histological evaluation.

RESULTS

Rats in the crush group recovered toe spread between 5 and 8 days after surgery. Rats with nerve transfers demonstrated electrophysiological and histological findings of nerve regeneration but no behavioral recovery.

CONCLUSIONS

Ulnar nerve axons regrew into the superficial radial nerve and then into the PIN to reinnervate the extensor digitorum communis. We were unable to demonstrate behavioral recovery because rats cannot readapt to cross-nerve transfer.

Reconstruction of C5-C8 (T1 Hand) Brachial Plexus Paralysis in a Series of 52 Patients

PURPOSE

A C5-C8 brachial plexus root injury, also known as a T1 hand, is associated with paralysis of shoulder abduction or external rotation and elbow flexion, accompanied by variable elbow, wrist, thumb, or finger extension deficits. We report the results of reconstruction for C5-C8 brachial plexus paralysis in 52 patients operated upon within 12 months of injury and having at least 24 months of follow-up.

METHODS

We considered surgery to be indicated if, by the fifth month after trauma, shoulder abduction and external rotation and elbow flexion remained paralyzed. Root grafting was possible in 35% of the patients and was performed concomitantly with nerve transfers. Shoulder motion was reconstructed by transferring the spinal accessory to the suprascapular nerve. Elbow flexion was restored by transferring fascicles from either the median or ulnar nerve to the biceps motor branch. When needed, elbow extension was reconstructed by transferring 1 motor branch of the flexor carpi ulnaris to the triceps lower medial head motor branch. Wrist extension was restored by transferring the distal anterior interosseous nerve to the extensor carpi radialis brevis motor branch.

RESULTS

Within 12 months of injury, we observed preserved or spontaneous recovery of elbow, wrist, finger, and thumb extension in 25%, 12%, 50%, and 68% of patients, respectively. After surgical reconstruction, improved range of motion for shoulder, elbow flexion, and wrist extension scoring at least M3 was present in 90% of our patients. All 10 patients in whom a motor branch of the flexor carpi ulnaris was used for triceps reconstruction recovered elbow extension, while flexor carpi ulnaris function was preserved.

CONCLUSIONS

In approximatively 90% of our patients, distal nerve transfers resulted in functional recovery of shoulder abduction, elbow flexion or extension, and wrist extension.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Reconstruction of a C7-T1 brachial plexus lower root injury by transferring multiple nerves and a free gracilis muscle: Case report

Lower-type brachial plexus injuries (BPI) are uncommon, and traditional reconstruction with tendon transfer procedures generally produce mediocre results. However, the advent of nerve transfers has rejuvenated the reconstructive options for peripheral nerve and spinal cord injuries. In this paper, we report the case 32 year-old patient with a C7-T1 avulsion BPI in whom multiple motor and sensory nerve transfers, combined with a free gracilis muscle flap transfer, were used to restore upper-limb functional defects. Five months after injury, several nerves were transferred (posterior division of the axillary nerve to motor nerve branches of the triceps, extensor carpi radialis brevis to flexor pollicis longus, supinator to the posterior interosseous nerve, brachialis to the ulnar nerve, and a cutaneous branch to the palm of the median nerve to the ulnar proper palmar digital nerve of the little finger). No complications occurred. M4 strength elbow extension, complete active finger extension and ulnar protective sensation were obtained. However, unsuccessful finger flexion reconstruction required a free gracilis muscle flap transfer motorized by the distal branch of the pronator teres, performed 43 months after the first surgery and resulting in complete finger flexion. Multiple nerve transfers might be a valid strategy for reconstructing lower BPIs, either in their early or late stage, which might be combined with a free gracilis muscle flap transfer.

Outcomes of Radial Nerve Grafting In Children After Distal Humerus Fracture

PURPOSE

To report the results of radial nerve grafting in 7 children who sustained a radial nerve injury following a distal humeral fracture.

METHODS

Seven children, mean age 6 years (range, 4-11 years), underwent nerve grafting for radial nerve injuries following distal humeral fractures. The mean interval between injury and surgery was 6.7 months (range, 6-9 months). In all cases, 3 sural nerve graft cables were used, of mean length 8.6 cm (range, 6-12 cm). Mean follow-up was 19.9 months (range, 12-24 months). Wrist, finger, and thumb extension range of motion and strength were evaluated at final follow-up, using the British Medical Research Council (BMRC) rating scale.

RESULTS

The radial nerve was entrapped within the fracture site in 2 patients, and in 5, it was completely interrupted without entrapment. All patients obtained full active wrist extension with grade M4 BMRC strength. For finger extension, all patients were graded as M4, obtaining full metacarpophalangeal finger and thumb extension, with the wrist in neutral in 3 patients and fully extended in 4. During the thumbs-up test, 4 patients achieved complete extension of all thumb joints, and 3 exhibited metacarpophalangeal extension lag, averaging 30°.

CONCLUSIONS

Nerve grafting of radial nerve injuries at the level of the distal humerus in children can yield excellent outcomes.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic V.

Transfer of the musculocutaneous nerve branch to the brachialis muscle to the triceps for elbow extension: anatomical study and report of five cases

We report the study of the anatomical feasibility of transferring the nerve to the brachialis muscle to the upper medial head motor branch that innervate the triceps, and outcomes of such transfers in restoring elbow extension in five patients with posterior cord lesion of the brachial plexus. The length of the branches to the brachialis muscle measured 7.6 cm and the triceps upper medial head motor branch was 5 cm in 10 adult cadavers. Five male patients were treated with this transfer 5 months after the injury (range 4 to 6 months) after posterior cord injury of the brachial plexus with a mean follow-up of 31 months (range 28 to 36 months). Elbow extension scored M4 in all cases. No complications occurred. These preliminary results suggest that transferring the nerve to the brachialis muscle is an effective technique for the reconstruction of elbow extension after posterior cord brachial plexus injuries.

LEVEL OF EVIDENCE

IV.

Patterns of Brachial Plexus Stretch Palsy in a Prospective Series of 565 Surgically Treated Patients

PURPOSE

To report the distribution of the different patterns of stretch brachial plexus injuries (BPIs) in a retrospective cohort of patients operated at our institution during an 11-year period.

METHODS

From September 2002 to June 2012, we evaluated and operated on 565 patients with traction injuries of the brachial plexus. Average age was 26.8 years (SD ±9.3 years); the interval between the injury and surgery was 5.4 months (SD ±2.8 months). The pattern of injury was defined based on data obtained from a standardized clinical examination, preoperative helical computed tomography myelography after intradural contrast injection, surgical findings, and intraoperative electric stimulation.

RESULTS

Supraclavicular injuries accounted for 91% of all cases (N = 512) whereas 9% of injuries were infraclavicular. Within the supraclavicular injuries, 50% of cases involved the entire plexus and in 12% there was avulsion of all 5 roots. Among them, 94% involved the upper plexus (C5 to C6 ± C7 ± C8), and 6% the lower plexus (C8 to T1 ± C7). C5 to C6 injuries accounted for 23% of partial BPI, C5 to C7 19%, C5 to C8 52%, C7 to T1 4%, and C8 to T1 2%.

CONCLUSIONS

The most relevant findings of this study were that most panplexal BPIs showed at least one graftable root, there was a high prevalence of C5 to C8 BPI, C7 to T1 root injury was the most common pattern of lower type of injury, and infraclavicular BPI was uncommon.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic IV.

The Towel Test: A Useful Technique for the Clinical and Electromyographic Evaluation of Obstetric Brachial Plexus Palsy

The towel test consists of covering an infant’s face with a towel and seeing if he/she can remove it with either arm. In this study it has been used to aid the clinical and electromyographic assessment of 21 infants with obstetric brachial plexus palsy. At 2 to 3 months, none of the 21 infants succeeded in removing the towel, either with their normal or affected arm. At 6 months, all the infants succeeded in removing the towel with their normal arm, but 11 could not with their affected arm, and the same was observed at a further assessment at 9 months. The towel test is a reliable technique for evaluating children with obstetric brachial plexus injuries.

Nerve transfer for sensory reconstruction of C8-T1 dermatomes in tetraplegia

OBJECTIVES

Absence of sensation in C8-T1 dermatome is a common finding in midcervical spinal cord injury. The goal was to restore sensation on the C8-T1 dermatomes by transferring sensory nerves with afferents on C5-C6 roots.

METHODS

A mean 10 months post spinal cord injury, we operated on 10 upper limbs from 5 tetraplegics averaging 23 years old. Cutaneous branches of the median nerve were transferred to the palm to the ulnar proper digital nerve of the little finger. In two patients, the lateral antebrachial cutaneous nerve was also transferred to the medial antebrachial cutaneous nerve.

RESULTS

At a mean 20 months after surgery, on the ulnar side of the hand and little finger, all patients were able to perceive 19.3 g Semmes-Weinstein monofilament pressure. Nociception was restored on the medial side of the elbow, forearm, and hand. Faulty location was a common finding, but not as a major complaint.

CONCLUSIONS

Sensory nerve transfers should be incorporated into the reconstruction of the upper limb in tetraplegics. © 2015 Wiley Periodicals, Inc. Microsurgery 36:637-641, 2016.

Nerve transfers for restoration of finger flexion in patients with tetraplegia

OBJECTIVE The purpose of this paper was to report the authors' results with finger flexion restoration by nerve transfer in patients with tetraplegia. METHODS Surgery was performed for restoration of finger flexion in 17 upper limbs of 9 patients (8 male and 1 female) at a mean of 7.6 months (SD 4 months) after cervical spinal cord injury. The patients' mean age at the time of surgery was 28 years (SD 15 years). The motor level according to the ASIA (American Spinal Injury Association) classification was C-5 in 4 upper limbs, C-6 in 10, and C-7 in 3. In 3 upper limbs, the nerve to the brachialis was transferred to the anterior interosseous nerve (AIN), which was separated from the median nerve from the antecubital fossa to the midarm. In 5 upper limbs, the nerve to the brachialis was transferred to median nerve motor fascicles innervating finger flexion muscles in the midarm. In 4 upper limbs, the nerve to the brachioradialis was transferred to the AIN. In the remaining 5 upper limbs, the nerve to the extensor carpi radialis brevis (ECRB) was transferred to the AIN. Patients were followed for an average of 16 months (SD 6 months). At the final evaluation the range of finger flexion and strength were estimated by manual muscle testing according to the British Medical Research Council scale. RESULTS Restoration of finger flexion was observed in 4 of 8 upper limbs in which the nerve to the brachialis was used as a donor. The range of motion was incomplete in all 5 of these limbs, and the strength was M3 in 3 limbs and M4 in 1 limb. Proximal retrograde dissection of the AIN was associated with better outcomes than transfer of the nerve to the brachialis to median nerve motor fascicles in the arm. After the nerve to the brachioradialis was transferred to the AIN, incomplete finger flexion with M4 strength was restored in 1 limb; the remaining 3 limbs did not show any recovery. Full finger flexion with M4 strength was demonstrated in all 5 upper limbs in which the nerve to the ECRB was transferred to the AIN. No functional downgrading of elbow flexion or wrist extension strength was observed. CONCLUSIONS In patients with tetraplegia, finger flexion can be restored by nerve transfer. Nerve transfer using the nerve to the ECRB as the donor nerve produced better recovery of finger flexion in comparison with nerve transfer using the nerve to the brachialis or brachioradialis.

High Median Nerve Injury: Motor and Sensory Nerve Transfers to Restore Function

This article describes the clinically significant motor and sensory deficits that follow high median nerve injuries and addresses the indications, limitations, and outcomes of nerve transfers, when striving to overcome the deficits these patients' experiences. Preferred surgical reconstructive strategy using motor and sensory nerve transfers, and surgical techniques used to perform these transfers, are described.

Injury mechanisms in supraclavicular stretch injuries of the brachial plexus

The aim of this study was to describe the mechanisms involved in stretch injuries of the brachial plexus. One hundred and fifty consecutive patients with supraclavicular brachial plexus injuries (BPI) were asked about the mechanism of injury during the actual injury event, particularly about the type of trauma to their shoulder, shoulder girdle and head. Fifty-seven of the patients provided enough information about their accident to allow for analysis of the shoulder trauma. The injury mechanism for all patients having upper root or total palsy (n=46) was described as a direct vertical impact to the shoulder. In 44 of these patients, the trauma followed a motorcycle accident and, in most of them, the patient hit a fixed vertical structure before falling to the ground. The injury mechanism for the lower root palsy cases (n=11) was variable. The most frequent mechanism was forceful anterior shoulder compression by a car seat belt. We found that injury mechanisms differed significantly from the ones commonly discussed in published studies.

Reappraisal of Clinical Deficits Following High Median Nerve Injuries

PURPOSE

To describe clinically apparent motor and sensory deficits in a cohort of 11 patients with isolated injury of the median nerve above the elbow and compare them against similar cases reported in the literature.

METHOD

Eleven patients of mean age 30 years (SD ± 14 years; 6 males, 5 females) were examined a mean of 21 weeks (SD ± 16 weeks) after an isolated high median nerve injury. Pronation, wrist flexion, and finger flexion range of motion and strength (British Medical Research Council scale) were evaluated. Grasp and lateral pinch strength were assessed bilaterally using a dynamometer. Thumb opposition was evaluated using the Kapandji score. Sensory impairment was considered significant when there was no perception of a 2.0-g Semmes-Weinstein filament.

RESULTS

Pronation was largely preserved in all patients to a mean range of motion of 52° (SD ± 13°), and pronation strength was M4 in 10 of 11 patients. Wrist flexion scored M5 in all patients. Thumb and index distal interphalangeal joint flexion were absent in all patients. In all patients, middle, ring, and little finger flexion was complete and scored M5. Thumb function scored above 5 in all patients, averaging 7.5 (SD ± 1.2) on the Kapandji scale. Grasp and pinch strength were 43% (SD ± 12%) and 36% (SD ± 11%) of the contralateral (normal) limb, respectively. Impaired sensation of a 2.0-g monofilament was found only in the palmar region over the middle and distal phalanges of the index and middle fingers and the distal phalanx of the thumb.

CONCLUSIONS

Noteworthy discrepancies were identified between the clinical motor and sensory deficits described in the literature and those observed in our patients.

CLINICAL RELEVANCE

In most patients with a high median nerve injury, only thumb and index flexion and palmar sensation warrant surgical reconstruction. Decreased grasp and pinch strength was a major finding that should also be addressed by surgery.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic IV.

Transfer of a Terminal Motor Branch Nerve to the Flexor Carpi Ulnaris for Triceps Reinnervation: Anatomical Study and Clinical Cases

PURPOSE

To analyze the anatomical feasibility of transferring a motor branch nerve to the flexor carpi ulnaris (FCU) to the triceps upper medial head motor branch (UMHM) and to report the resultant outcome of the restoration of elbow extension in 5 patients with extensive brachial plexus injury.

METHODS

The ulnar and radial nerves were dissected in 10 cadavers. We measured the length and diameter of the branches to the FCU and the UMHM branch and counted the axons. Then, 5 male patients, mean age 30 years, underwent FCU nerve branch transfer for reconstruction of elbow extension. Elbow flexion was restored via a median nerve branch to biceps transfer.

RESULTS

Mean UMHM nerve length and diameter were 86 and 1.5 mm, respectively. Mean number of branches to the FCU muscle was 2.9. Mean FCU nerve length and diameter were 50 and 1.0 mm, respectively. Mean number of myelinated fibers was 818 and 743 for the UMHM and the longest branch to the FCU, respectively. Coaptation between nerves was possible without tension. All patients recovered functional active elbow extension at a mean follow-up of 19 months with a British Medical Research Council score of M4. After surgery, all patients retained a functional FCU with a British Medical Research Council score of M4.

CONCLUSIONS

Nonselective ulnar nerve fascicles at the root of the limb might not be adequate to restore elbow extension when combined with a median nerve branch transfer for elbow flexion. A selective distal ulnar motor fascicle such as a FCU motor branch could be harvested and connected to a triceps branch to restore elbow extension. Such a nerve transfer would also allow for later transfer of the still functional FCU tendon to the digital extensors.

CLINICAL RELEVANCE

For patients with extensive brachial plexus injury and a preserved medial cord, transferring a motor branch nerve to the FCU is an effective technique for the reconstruction of elbow extension.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Thoracodorsal nerve transfer for triceps reinnervation in partial brachial plexus injuries

PURPOSE

To report the clinical outcomes of thoracodorsal nerve (TDN) transfers to the triceps motor branches for elbow extension restoration in patients with partial brachial plexus injuries (BPI).

METHODS

Eight male patients of mean age 23 years and suffering from a partial BPI underwent direct coaptation of the TDN to the nerve of the upper medial and long heads of the triceps, an average 6 months after their accident.

RESULTS

Seven patients achieved M4 elbow extension strength and one patient M3, according to the BMRC scale, after a mean follow-up of 21 months.

DISCUSSION

Direct TDN transfer might be a valid surgical procedure for the restoration of elbow extension in patients with partial BPI.

Stretch-induced nerve injury: a proposed technique for the study of nerve regeneration and evaluation of the influence of gabapentin on this model

The rat models currently employed for studies of nerve regeneration present distinct disadvantages. We propose a new technique of stretch-induced nerve injury, used here to evaluate the influence of gabapentin (GBP) on nerve regeneration. Male Wistar rats (300 g; n=36) underwent surgery and exposure of the median nerve in the right forelimbs, either with or without nerve injury. The technique was performed using distal and proximal clamps separated by a distance of 2 cm and a sliding distance of 3 mm. The nerve was compressed and stretched for 5 s until the bands of Fontana disappeared. The animals were evaluated in relation to functional, biochemical and histological parameters. Stretching of the median nerve led to complete loss of motor function up to 12 days after the lesion (P<0.001), compared to non-injured nerves, as assessed in the grasping test. Grasping force in the nerve-injured animals did not return to control values up to 30 days after surgery (P<0.05). Nerve injury also caused an increase in the time of sensory recovery, as well as in the electrical and mechanical stimulation tests. Treatment of the animals with GBP promoted an improvement in the morphometric analysis of median nerve cross-sections compared with the operated vehicle group, as observed in the area of myelinated fibers or connective tissue (P<0.001), in the density of myelinated fibers/mm² (P<0.05) and in the degeneration fragments (P<0.01). Stretch-induced nerve injury seems to be a simple and relevant model for evaluating nerve regeneration.

Variation in nerve autograft length increases fibre misdirection and decreases pruning effectiveness. An experimental study in the rat median nerve

OBJECTIVES

In the clinical set, autologus nerve grafts are the current option for reconstruction of nerve tissue losses. The length of the nerve graft has been suggested to affect outcomes. Experiments were performed in the rat in order to test this assumption and to detect a possible mechanism to explain differences in recovery.

METHODS

The rat median nerve was repaired by ulnar nerve grafts of different lengths. Rats were evaluated for 12 months by behavioural assessment and histological studies, including ATPase myofibrillary histochemistry and retrograde neuronal labelling.

RESULTS

It was demonstrated that graft length interferes in behavioural functional recovery that here correlates to muscle weight recovery. Short nerve grafts recovered faster and better. Reinnervation was not specific either at the trunk level or in the muscle itself. The normal mosaic pattern of Type I muscle fibres was never restored and their number remained largely augmented. An increment in the number of motor fibres was observed after the nerve grafting in a predominantly sensory branch in all groups. This increment was more pronounced in the long graft group. In the postoperative period, about a 20% reduction in the number of misdirected motor fibres occurred in the short nerve graft group only.

CONCLUSION

Variation in the length of nerve grafts interferes in behavioural recovery and increases motor fibres misdirection. Early recovery onset was related to a better outcome, which occurs in the short graft group.

Clinical findings in C5-C6 and C5-C7 root palsies with brachial plexus traction lesions

Stretch injuries of the C5-C7 roots of the brachial plexus traditionally have been associated with palsies of shoulder abduction/external rotation, elbow flexion/extension, and wrist, thumb, and finger extension. Based on current myotome maps we hypothesized that, as far as motion is concerned, palsies involving C5-C6 and C5-C7 root injuries should be similar. In 38 patients with upper-type palsies of the brachial plexus, we examined for correlations between clinical findings and root injury level, as documented by CT tomomyeloscan. Contrary to commonly held beliefs, C5-C7 root injuries were not associated with loss of extension of the elbow, wrist, thumb, or fingers, but residual hand strength was much lower with C5-C7 vs C5-C6 lesions.

Results and current approach for Brachial Plexus reconstruction

We review our experience treating 335 adult patients with supraclavicular brachial plexus injuries over a 7-year period at the University of Southern Santa Catarina, in Brazil. Patients were categorized into 8 groups, according to functional deficits and roots injured: C5-C6, C5-C7, C5-C8 (T1 Hand), C5-T1 (T2 Hand), C8-T1, C7-T1, C6-T1, and total palsy. To restore function, nerve grafts, nerve transfers, and tendon and muscle transfers were employed. Patients with either upper- or lower-type partial injuries experienced considerable functional return. In total palsies, if a root was available for grafting, 90% of patients had elbow flexion restored, whereas this rate dropped to 50% if no roots were grafted and only nerve transfers performed. Pain resolution should be the first priority, and root exploration and grafting helped to decrease or eliminate pain complaints within a short time of surgery.

Transfer of supinator motor branches to the posterior interosseous nerve to reconstruct thumb and finger extension in tetraplegia: case report

We treated a patient with tetraplegia who had paralysis of thumb and finger extension by transferring supinator motor branches to the posterior interosseous nerve. Surgery was performed bilaterally, 7 months after a spinal cord injury. Six months after surgery, with the wrist in neutral, extension of the thumb and finger were almost full, bilaterally. In tetraplegic patients with strong wrist extensors, supinator motor branch transfer is a promising new alternative for the reconstruction of thumb and finger extension.

Transfer of the supinator muscle to the extensor pollicis brevis for thumb extension reconstruction in C7-T1 brachial plexus palsy

With C7-T1 brachial plexus injuries, finger motion is absent while shoulder, elbow and wrist function are largely preserved. Previously, we have reconstructed finger flexion by transferring the brachialis muscle to the flexor digitorum profundus and flexor pollicis longus; and we have restored extension of thumb and finger by transferring the motor nerve to the supinator to the posterior interosseous nerve, which is only feasible in fresh injuries. We describe the transfer of the supinator muscle to the extensor pollicis brevis to reanimate thumb extension in patients with long standing C7-T1 brachial plexus palsy.

Pain after avulsion injuries and complete palsy of the brachial plexus: the possible role of nonavulsed roots in pain generation

OBJECTIVE

Pain after complete brachial palsy has been attributed to the deafferentation of the spinal cord subjected to root avulsion. However, the large majority of patients have at least one nonavulsed root. We postulated that pain, be it subacute or chronic, originates in the stump of the nonavulsed roots.

METHODS

Thirty-six patients underwent brachial plexus grafting within 8 months of their initial injury. Ten other patients with palsy that had lasted for more than 2 years underwent selective, computed tomography-guided anesthetic blocks of the nonavulsed root. Pain was evaluated at different intervals, using a numerical scale ranging from 0 (no pain) to 10 (severe pain).

RESULTS

In all groups, pain decreased substantially or disappeared after a local anesthetic block or grafting. In the patients who underwent grafting, pain reduction was noted the first day after surgery in 56% of the 36 patients. Three weeks after surgery, pain decreased dramatically, by 80% (P < 0.001). By 12 months after surgery, pain had decreased by 90%, and within 24 months, by 95%. Only the difference between 3 weeks and 24 months after surgery was significant (P < 0.001). At final evaluation, 80% of the patients receiving grafts reported either no or minimal pain.

CONCLUSION

Our data suggest that nonavulsed roots mediate pain in subacute and chronic complete brachial plexus palsy.

Triceps Motor Nerve Branches as a Donor or Receiver in Nerve Transfers

Objective:

The pattern of triceps innervation is complex and, as yet, has not been fully elucidated. The purposes of this study were 1) to clarify the anatomy of the triceps motor branches, and 2) to evaluate their possible uses as a donor or receiver for nerve transfer.

Methods:

The radial nerve and its motor and cutaneous branches were bilaterally dissected from the axilla and posterior arm regions of 10 embalmed cadavers.

Results:

A single branch innervates the triceps long head, whereas double innervation was identified for the lateral and medial heads. The upper branch to the lateral head originated from the radial nerve, whereas the lower branch to the lateral head stemmed from the lower medial head motor branch, which ultimately innervated the anconeus muscle. Both the long head and the upper medial head motor branches originated in the axillary region in the vicinity of the latissimus dorsi tendon.

Conclusion:

Each of the triceps’ motor branches might be used as a donor for transfer. The triceps long head motor branch should be used preferentially when the intention is to establish triceps reinnervation.

The course of aberrant reinnervation following nerve repair with fresh or denatured muscle autografts

Denatured muscle grafts obtained by freeze thawing have been proposed to replace losses in the peripheral nerves. In the present report, we compare the performance of such grafts with fresh grafts in the rat median nerve. A long-term effect of muscle interposition on reinnervation was studied by behavioral assessment, muscle ATPase histochemistry, and retrograde labeling of motoneurons. There was no difference in grasping strength recovery between fresh and denatured 10-mm-long muscle grafts. Recovery was delayed and incomplete. Twelve months after surgery, only 50% of the normal grasping strength was attained. Grasping recovery was not observed in the 20-mm-long graft groups. Pathway reinnervation was non-specific with a huge amount of motor fiber misdirection. A decrease in the number of misdirected motor fibers occurred with time and activity recovery. Muscle reinnervation was not specific with disturbance of the mosaic pattern and type-grouping formation. Preference of type I axons for reinnervating deeper zones was observed. Type I aberrant reinnervation was demonstrated in the muscle periphery. The mosaic distribution of type I and II muscle fibers was not stable, and readjustments were observed with time, correlating with grasping improvement. During grasping strength recovery, there was a decrease in the number of type I fibers peripherally located and an increase of those deeply disposed. A time- and activity-related recovery was associated with readjustment in the pathways and muscle fiber rearrangement. We suggest that muscle activity generates specificity.

Brachial plexus dorsal rhizotomy in the treatment of upper-limb spasticity

OBJECT

This study was conducted to evaluate the effects of dorsal rhizotomy on upper-limb spasticity, functional improvement, coordination, and hand sensibility.

METHODS

Fifteen spastic upper limbs in 13 patients were selected and prospectively studied. Brachial plexus dorsal rhizotomy was performed in which two, three, or four dorsal roots were completely sectioned. Patients were followed up for at least 12 months after surgery; the mean follow-up period was 15.6 months and the maximum period was 30 months. A remarkable relief of spasticity was observed in all cases. Recurrence was observed in only one patient and was caused by insufficient dorsal root section. Functional improvement was observed in all cases, and functional improvement in the hand was found to be related to the presence of active finger extension in the preoperative period. Even when extended dorsal root section was performed, no hand anesthesia, either total or partial, was observed. No patient lost movement ability in the postoperative period, and no ataxic limbs were observed.

CONCLUSIONS

Brachial plexus dorsal rhizotomy is very effective as a treatment for upper-limb spasticity and results in functional improvement without loss of sensation in the hand.

A surgical approach for concomitant spinal cord and brachial plexus surgery: an anatomical study

Spinal cord surgery is not the current treatment for brachial plexus avulsion injuries. However, several experimental and a few clinical cases have been reported with promising results. This surgical strategy in the near future, might prove to be useful. Different simultaneous anatomical approaches to the brachial plexus and spinal cord were studied in attempt to discover the best route to be used in the surgical reconstruction of avulsion lesions of the brachial plexus by spinal cord surgery. Eleven fresh subjects were used to compare: a) simultaneous dorsal approaches to the brachial plexus and spinal cord, b) the dorsal approach to the spinal cord and the anterior approach to the brachial plexus, c) a dorsal approach to the spinal cord combined with a dorsal approach through the triceps muscle to the terminal branches of the brachial plexus and d) a purely anterior approach to the spinal cord and brachial plexus. During the study, special attention was paid to the length of the grafts needed for repair, the possibility of entire exposure of the brachial plexus and the possibility of performing concomitant nerve transfers. As a result of the anatomical findings, we would suggest a dorsal approach to the spinal cord, suprascapular nerve and sometimes to the axillary nerve, combined with an anterior exposure to the brachial plexus in order to have the whole plexus explored and routine simultaneous nerve transfers performed. In selected cases, with limited root injuries, the dorsal approach to the brachial plexus and spinal cord and the anterior approach to the brachial plexus and spinal cord might be of interest.

Selective motor hyperreinnervation by using contralateral C-7 motor rootlets in the reconstruction of an avulsion injury of the brachial plexus. Case report

Brachial plexus avulsion injuries are a clinical challenge. In recent experimental studies the authors have demonstrated the high degree of muscle reinnervation attained when a C-4 motor rootlet was directly connected to the musculocutaneous nerve. This degree of reinnervation was attributed to the good chance that a muscle fiber can be reinnervated by a motor fiber when the number of regenerating motor neurons is increased and when competitive sensory fibers are excluded from the process. The authors present the first clinical case in which this phenomenon has been observed. This 26-year-old man, who was involved in an automobile accident, presented with an upper brachial plexus avulsion, for which he underwent operation 4 months later. The axillary and suprascapular nerves were directly surgically connected to the motor rootlets of the C-7 contralateral root by using two cables of sural nerve graft. Two years postsurgery, the patient was able to perform shoulder abduction of 120 degrees and hold an 800-g weight at 90 degrees. These results are encouraging, and in selected patients motor rootlet transfer might prove to be a useful surgical strategy.