Transfer of the phrenic nerve to musculocutaneous nerve via sural nerve graft after total brachial plexus injury

A middle age male presented a right total brachial plexus injury after motorcycle fall one year ago. Subsequent electromyographic evaluation was consistent with C5, C6, C7, C8 and T1 root avulsion. The patient was submitted to a right transfer of the phrenic nerve to musculocutaneous nerve , using rural nerve graft.

[Anatomical variants of the median and musculocutaneous nerve - a case report]

Traumatische Schädigungen des Plexus brachialis resultieren häufig in einer eingeschränkten oder aufgehobenen Flexionsbewegung des Ellenbogens. Die Wiederherstellung dieser Bewegung ist ein wichtiges Ziel der chirurgischen Therapie 1 2. Maßgeblich für die Flexionsbewegung und Innervation der Zielmuskeln ist der N. musculocutaneus (MSC). Dieser bildet einen der beiden Endäste des Fasciculus lateralis des Plexus brachialis (C5-C7). In den meisten Fällen verläuft er an der ventralen Oberarmseite, in der Flexorenloge, zwischen dem M. brachialis und M. biceps brachii nach distal und gibt Äste zur motorischen Innervation der beiden Muskeln ab. Er verläuft anschließend durch den Sulcus bicipitalis lateralis und durchbricht die Fascia brachii in der Ellenbeuge 3 um als Nervus cutaneus antebrachii lateralis, sensibel den Unterarm zu versorgen. Variable Verläufe des Plexus brachialis in Zusammenschau mit dem N. musculocutaneus sind beschrieben und können auf vielseitige Art und Weisen imponieren 4 5. So kann der N. musculocutaneus direkte Verbindungen zum N.medianus aufweisen, oder diesen als direkter dritter Zuschuss anteilweise bilden. Der N. medianus kann also sowohl Äste an den N. musculocutaneus abgeben als auch solche von diesem erhalten. Vorliegende Kadaverstudien zeigen in über 50+% der Fälle Verbindungen zwischen dem N. musculocutaneus und dem N. medianus, wobei ein Großteil solcher Verbindungen proximal des Eintrittes des N. musculocutaneus in den M. coracobrachialis liegt 6. Trotzdem sind diese Variationen im klinischen Alltag meist Zufallsbefunde bei chirurgischen Interventionen 7.

A favourable suture method for size-mismatched nerve transfer: a case series of intercostal-to-musculocutaneous nerve transfer for brachial plexus injury

We review a nerve suture method for size-mismatched nerve transfers and report a case series involving patients with brachial plexus injury who underwent intercostal-to-musculocutaneous nerve transfer using this method.

The utility of selective partial neurectomy of the musculocutaneous nerve in children with bilateral spastic elbow

PURPOSE

This study aims to determine the utility of selective partial neurectomy of the musculocutaneous nerve (MCN) in pediatric patients with bilateral spastic elbow.

METHODS

A prospective, cross-sectional, case series study was performed in nine pediatric patients (four females and five males) with bilateral spastic elbow, all with a 11.4-year-old average age, where 18 selective partial neurectomies of the MCN were carried out. They were evaluated with goniometry of both spastic elbows at resting position and active amplitude, and staging spasticity employing the Modified Ashworth Scale (MAS) in the preoperative and postoperative period. The results are reported 1 year after surgery.

RESULTS

The etiology of the spasticity was secondary to cerebral palsy in eight patients (88.8%) and in one patient (11.11%) secondary to traumatic brain injury. A clinical improvement was observed in goniometry comparing the preoperative and postoperative resting position, a mean preoperative of 44.38 degrees (SD ± 7.61) versus 98.05 degrees (SD ± 24.44), respectively, and preoperative active amplitude a mean of 86.55 degrees (SD ± 15.97) versus the mean postoperative of 47.33 (SD ± 17.86). A relevant decrease on the MAS after surgical intervention was observed, resulting from an average preoperative state according to MAS of 3.78 (SD ± 0.42) to a postoperative state according to MAS of 1.44 (SD ± 0.51), these changes being statistically significant (p ≤ 0.001). No postoperative complications were observed.

CONCLUSIONS

Selective partial neurectomy of the MCN has shown good results in patients with bilateral spastic elbow in whom antispastic drugs and physical therapy have failed, and has prove permanent effects.

[Modification of intercostobrachial neurotization of musculocutaneous and axillary nerves in total brachial plexopathy: description of technique and literature review]

BACKGROUND

Intercostobrachial neurotization is one of the few approach for partial motor recovery of extremity in patients with total trauma of brachial plexus. However, direct coaptation with musculocutaneous nerve is often impossible due to different anatomy of intercostal nerves and their functional failure at several levels. This necessitates the use of intermediate graft that deteriorates the final outcome.

OBJECTIVE

To develop an alternative method for direct coaptation of musculocutaneous nerve with insufficiently long intercostal donor nerves.

MATERIAL AND METHODS

The study included 26 patients with total post-traumatic plexitis. All patients underwent intercostobrachial neurotization of musculocutaneous and axillary nerves. Original technique of direct selective neurotization of motor fascicular groups of musculocutaneous and axillary nerves was used in 11 cases.

RESULTS AND DISCUSSION

A modified variant of intercostobrachial neurotization of musculocutaneous and axillary nerves consists in mobilization and transposition of recipient nerves in axillary region. This makes it possible to reduce the distance to donor nerves and, in most cases, to carry out direct neurotization without autologous grafts. Among 11 patients, restoration of shoulder abduction and elbow flexion was obtained in 7 patients (77 %).

CONCLUSION

The proposed adaptive technique makes it possible to avoid graft lengthening in some cases and provides satisfactory results.

Acellular nerve graft enriched with mesenchymal stem cells in the transfer of the phrenic nerve to the musculocutaneous nerve in a C5-C6 brachial plexus avulsion in a rat model

INTRODUCTION

Phrenic nerve transfer has been shown to achieve good nerve regeneration in brachial plexus avulsion. Acellular nerve allografts (ANAs) showed inferior results to autografts, which is why its use with mesenchymal stem cells (MSCs) is currently being studied. The aim is to study the effect of BM-MSCs associated with ANAs in a rat model of phrenic nerve transfer to the musculocutaneous nerve in a C5-C6 avulsion.

MATERIAL AND METHODS

42 Wistar-Lewis rats underwent a C5-C6 lesion in the right forelimb by excising a 3 mm segment from both roots, followed by a phrenic nerve transfer to the musculocutaneous nerve associated with the interposition of a three types of nerve graft (randomly distributed): control (autograft) group (n = 12), ANAs group (n = 12), and ANAs + BM-MSCs group (n = 18) After 12 weeks, amplitude and latency of the NAP and the compound motor action potential (CMAP) were measured. Biceps muscles were studied by histological analysis and nerve grafts by electron microscopy and fluorescence analysis.

RESULTS

Statistically significant reductions were found in latency of the CMAP between groups control (2.48 ± 0.47 ms) and experimental (ANAs: 4.38 ± 0.78 ms, ANAs + BM-MSCs: 4.08 ± 0.85 ms) and increases in the amplitude of the CMAP between groups control (0.04388 ± 0.02 V) and ANAs + BM-MSCs (0.02275 ± 0.02 V), as well as in the thickness of the myelin sheath between groups control (0.81 ± 0.07 μm) and experimental (ANAs: 0.72 ± 0.08 μm, ANAs + BM-MSCs: 0.72 ± 0.07 μm) and in the area of the myelin sheath between groups control (13.09 ± 2.67 μm² ) and ANAs (10.01 ± 2.97 μm² ) (p < .05). No statistically significant differences have been found between groups ANAs and ANAs + BM-MSCs.

CONCLUSIONS

This study presents a model for the study of lesions of the upper trunk and validates the autologous graft as the gold standard.

Differences in strength fatigue when using different donors in traumatic brachial plexus injuries

BACKGROUND

The purpose of this study was to assess the results of elbow flexion strength fatigue, rather than the maximal power of strength, after brachial plexus re-innervation with phrenic and spinal accessory nerves. We designed a simple but specific test to study whether statistical differences were observed among those two donor nerves.

METHOD

We retrospectively reviewed patients with severe brachial plexus palsy for which either phrenic nerve (PN) or spinal accessory nerve (SAN) to musculocutaneous nerve (MCN) transfer was performed. A dynamometer was used to determine the maximal contraction strength. One and two kilograms circular weights were utilized to measure isometrically the duration of submaximal and near-maximal contraction time. Statistical analysis was performed between the two groups.

RESULTS

Twenty-eight patients were included: 21 with a PN transfer while 7 with a SAN transfer for elbow flexion. The mean time from trauma to surgery was 7.1 months for spinal accessory nerve versus 5.2 for phrenic nerve, and the mean follow-up was 57.7 and 38.6 months, respectively. Statistical analysis showed a quicker fatigue for the PN, such that patients with the SAN transfer could hold weights of 1 kg and 2 kg for a mean of 91.0 and 61.6 s, respectively, while patients with transfer of the phrenic nerve could hold 1 kg and 2 kg weights for just a mean of 41.7 and 19.6 s, respectively. Both differences were statistically significant (at p = 0.006 and 0.011, respectively). Upon correlation analysis, endurances at 1 kg and 2 kg were strongly correlated, with r = 0.85 (p < 0.001).

CONCLUSIONS

Our results suggest that phrenic to musculocutaneous nerve transfer showed an increased muscular fatigue when compared with spinal accessory nerve to musculocutaneous transfer. Further studies designed to analyze this relation should be performed to increase our knowledge about strength endurance/fatigue and muscle re-innervation.

Double Motor Nerve Transfer for All Finger Flexion in Cervical Spinal Cord Injury: An Anatomical Study and a Clinical Report

PURPOSE

To explore the feasibility of restoring all finger flexion after a cervical spinal cord injury.

METHODS

Double nerve transfer was conducted in 22 cadaver upper extremities. Donor nerves were the brachialis branch of the musculocutaneous nerve and the extensor carpi radialis brevis (ECRB) branches of the radial nerve. Recipient nerves were the anterior interosseous nerve (AIN) and the flexor digitorum profundus (FDP) branch of ulnar nerve (ulnar-FDP). Nerve transfers were evaluated on 3 parameters: surgical feasibility, donor-to-recipient axon count ratio, and distance from the coaptation site to the muscle entry of recipient nerve. A complete C6 spinal cord injury reconstruction was accomplished in a patient using a double nerve transfer of ECRB to ulnar-FDP and brachialis to AIN.

RESULTS

In the cadaver study, nerve transfers from ECRB to AIN, brachialis to AIN, and ECRB to ulnar-FDP were all feasible. The transfer from the brachialis to ulnar-FDP was not possible. Mean myelinated axon counts of AIN, brachialis, ulnar-FDP, and ECRB were 2,903 ± 1049, 1,497 ± 606, 753 ± 364, and 567 ± 175, respectively. The donor-to-recipient axon count ratios of ECRB to AIN, brachialis to AIN, and ECRB to ulnar-FDP were 0.24 ± 0.15, 0.55 ± 0.38, and 0.98 ± 0.60, respectively. The distance from coaptation of the ECRB to the ulnar-FDP muscle entry was shorter than for the other nerve transfers (54 ± 14.29 mm). At 18 months, there was restoration of flexion in all fingers and functional improvement from double nerve transfer of the brachialis to the AIN and the ECRB to the ulnar-FDP.

CONCLUSIONS

Restoration of all finger flexion may be feasible by the ECRB to ulnar-FDP and brachialis to AIN double nerve transfer.

CLINICAL RELEVANCE

Double nerve transfer can be used in C6-C7 spinal cord injury and patients with lower arm-type brachial plexus injury who have no finger flexion but have good brachialis and ECRB.

Microsurgical anatomy of branches of musculocutaneous nerve: clinical relevance for spastic elbow surgery

PURPOSE

The neurotomy of musculocutaneous nerve is a treatment for patients who suffer from spastic elbow flexion when medical and reeducative treatments have failed. It consists in sectioning motor branches of musculocutaneous nerve which are destined to the biceps brachii and brachialis muscles, both being the main elbow flexor muscles. The aim of this study was to analyse the distance, where each motor branch arises from the musculocutaneous nerve to both biceps brachii and brachialis muscles, to establish precisely the localisation and length of the necessary incision to reach its branches for surgery.

MATERIALS AND METHODS

Eighteen musculocutaneous nerves from ten cadavers were dissected. None of them reported with a previous pathology. The cadavers were laid on the back with 30-35° of abduction, a complete extension, and supination of the upper limb.

RESULTS

The localization of motor branches was to be found in the middle third of the upper arm, with an average from the base of the humeral major tubercle of 11.46, 12.40, and 12.87 cm for the biceps brachii and 16.36, 19.10, and 16.88 cm for the brachialis muscle.

CONCLUSION

The incision needed to reach the motor branches of the musculocutaneous nerve should be localised between 10 and 20 cm from the major humeral tubercle and may be shorter than usual.

Outcome following phrenic nerve transfer to musculocutaneous nerve in patients with traumatic brachial palsy: a qualitative systematic review

BACKGROUND

The phrenic nerve can be transferred to the musculocutaneous nerve in patients with traumatic brachial plexus palsy in order to recover biceps strength, but the results are controversial. There is also a concern about pulmonary function after phrenic nerve transection. In this paper, we performed a qualitative systematic review, evaluating outcomes after this procedure.

METHOD

A systematic review of published studies was undertaken in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement. Data were extracted from the selected papers and related to: publication, study design, outcome (biceps strength in accordance with BMRC and pulmonary function) and population. Study quality was assessed using the "strengthening the reporting of observational studies in epidemiology" (STROBE) standard or the CONSORT checklist, depending on the study design.

RESULTS

Seven studies were selected for this systematic review after applying inclusion and exclusion criteria. One hundred twenty-four patients completed follow-up, and most of them were graded M3 or M4 (70.1 %) for biceps strength at the final evaluation. Pulmonary function was analyzed in five studies. It was not possible to perform a statistical comparison between studies because the authors used different parameters for evaluation. Most of the patients exhibited a decrease in pulmonary function tests immediately after surgery, with recovery in the following months. Study quality was determined using STROBE in six articles, and the global score varied from 8 to 21.

CONCLUSIONS

Phrenic nerve transfer to the musculocutaneous nerve can recover biceps strength ≥M3 (BMRC) in most patients with traumatic brachial plexus injury. Early postoperative findings revealed that the development of pulmonary symptoms is rare, but it cannot be concluded that the procedure is safe because there is no study evaluating pulmonary function in old age.

Basal cell carcinoma preferentially arises from stem cells within hair follicle and mechanosensory niches

Basal cell carcinoma (BCC) is characterized by frequent loss of PTCH1, leading to constitutive activation of the Hedgehog pathway. Although the requirement for Hedgehog in BCC is well established, the identity of disease-initiating cells and the compartments in which they reside remain controversial. By using several inducible Cre drivers to delete Ptch1 in different cell compartments in mice, we show here that multiple hair follicle stem cell populations readily develop BCC-like tumors. In contrast, stem cells within the interfollicular epidermis do not efficiently form tumors. Notably, we observed that innervated Gli1-expressing progenitors within mechanosensory touch dome epithelia are highly tumorigenic. Sensory nerves activate Hedgehog signaling in normal touch domes, while denervation attenuates touch dome-derived tumors. Together, our studies identify varying tumor susceptibilities among different stem cell populations in the skin, highlight touch dome epithelia as "hot spots" for tumor formation, and implicate cutaneous nerves as mediators of tumorigenesis.

Concurrent variations of median and musculocutaneous nerves and their clinical correlation--a cadaveric study

Variations of median nerve, musculocutaneous nerve and their communicating branches are of interest for anatomists and surgeons. These variations may be vulnerable to damage in surgical procedures. We examined median nerve and musculocutaneous nerve concurrently in 58 cadavers, i.e. 116 superior extremities, and found median nerve innervating muscle of the anterior compartment of arm in the absence of musculocutaneous nerve in 11.2% superior extremities, splitting of median nerve in the arm into median nerve proper and musculocutaneous nerve in 5.12% superior extremities, and communication between median and musculocutaneous nerves in 20.7% superior extremities. Knowledge of such anatomical variations is helpful for surgeons treating neoplasm or repairing trauma.

Results of c5 root grafting to the musculocutaneous nerve using pedicled, vascularized ulnar nerve grafts

PURPOSE

Vascularized nerve grafts are indicated for the repair of large nerve defects. In brachial plexus injuries, the poor prognosis for functional hand reconstruction when the lower roots are avulsed makes the ulnar nerve a potential donor for vascularized nerve grafts. We report on the results we obtained with reconstruction of elbow flexion using long pedicled ulnar nerve grafts that connected the C5 root to the musculocutaneous nerve.

METHODS

We prospectively studied 8 young adults with complete brachial plexus palsy with avulsion of the lower roots, who had surgical repair an average of 4.6 months after trauma. Pedicled ulnar nerve grafts, averaging 30 cm long, connected the C5 root to the musculocutaneous nerve. In order to rescue misdirected axons that could have regenerated into the cutaneous branch of the musculocutaneous nerve, we transferred this branch to the motor branch of the extensor carpi radialis brevis muscle. Outcomes for all 8 patients were assessed an average of 26.7 months after surgery, focusing on recovery of muscle strength, categorized using the Medical Research Council scale.

RESULTS

None of the patients recovered elbow flexion or wrist extension greater than M2.

CONCLUSIONS

In brachial plexus injuries, reconstruction of elbow flexion using a long, pedicled, vascularized nerve graft produces unsatisfactory results.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

End-to-side nerve repair: Attachment of a distal, compared with a proximal and distal, nerve segment

Regeneration occurs if a distal nerve segment is attached end-to-side to an intact donor nerve after the nerve has been injured. We investigated if attachment of a proximal nerve segment as well, as an extra source of axons, had any advantage over the single attachment of a distal nerve segment to the same donor nerve. In rats, a single distal radial nerve, or both the proximal and distal radial nerve segments, were attached end-to-side to the musculocutaneous nerve, and effects were examined up to eight months after the repair. Cell profiles were double-labelled, indicating recruitment of axons by collateral sprouting, but there were few such cells. There was a shift in the distribution of retrograde labelled neuronal cell profiles in spinal cord and in DRGs between the two types of repair. Both procedures resulted in axonal outgrowth and some functional recovery, but there was no improvement if a proximal nerve segment was also used as a source for axons.

[Axillary wound with complete vasculo-nervous section. Functional outcomes]

Axillary wound with complete vasculonervous section are rare in adults, males between 20 and 30 years being more affected. In children these lesions are even more rarely encountered. Immediate surgical repair of vascular and nervous sections is recommended. Neurological impalement may be severe when all nervous trunks in the axilla are affected. Recovery of the motor and sensitive deficit is a long process and is often partial, good functional outcome being rare. Recovery in children is supposed to be better due to a more rapid regenerative capacity of the nerves. We present the case of a 9-year-old boy with axillary wound and complete section of axillary artery, median, ulnar, radial and musculocutaneous nerves and medial cutaneous nerve of arm. Vascular reconstruction with venous graft and epiperineural nerve reconstruction was done. Kinetotherapy and physiotherapy was part of recovery treatment. Follow up at 15 months confirmed very good functional outcomes with almost complete motor and sensitive function of the limb.

Quantitative Characterization of Regenerating Axons after End-to-Side and End-to-End Coaptation in a Rat Brachial Plexus Model: A Retrograde Tracer Study

The efficacy of end-to-side repair as a method of nerve reconstruction has been questioned, and most studies that characterize the mode of re-innervation are marred by inappropriate experimental design and lack quantitative analysis. This makes characterization of re-innervating neurons confusing and consequently controversy remains as to the extent and source of reinnervating axons. In an experimental brachial plexus rat model, we transected the musculocutaneous nerve, labeled its neuron pool with Fast-Blue and joined the distal stump to the side of the intact ulnar nerve, or to the proximal stump of the divided ulnar nerve, to characterize neurons that reinnervate the recipient nerve. Tetramethyl-rhodamine dextran (TMRD) or fluoro-gold was used to map the reinnervating motor and sensory neurons at 12 weeks post-transection. No neurons originally labeled from musculocutaneous nerve were subsequently labeled with TMRD or fluoro-gold, showing that this original neuron pool does not contribute to re-innervation of the distal musculocutaneous nerve, but that reinnervation occurs solely by ulnar nerve motor and sensory axons. In the end-to-side group, 16.4% of the motor and 7% of the sensory donor ulnar nerve neurons re-innervated the musculocutaneous nerve exclusively, and a further 10% motor and 11.6% sensory innervated the musculocutaneous nerve by collateral sprouting of their axons. This compared to re-innervation by 62.6% of motor and 70.4% of ulnar nerve sensory neurons in the positive control that underwent end-to-end repair. Our results confirm the concept of collateral sprouting and support the use of end-to-side repair.

Physiological and clinical advantages of median nerve fascicle transfer to the musculocutaneous nerve following brachial plexus root avulsion injury

Object

Loss of biceps muscle function is a significant disability after brachial plexus root avulsion injuries. Nerve grafting techniques to reestablish anatomical and functional continuity between the spinal cord and the avulsed root have not proven successful. Using nerve transfers for functional restoration of root avulsion injuries appears to be effective and has physiological advantages for reducing regeneration distances. Since the early 1990s, the Oberlin technique of transferring ulnar nerve fascicles to the motor branch of the musculocutaneous nerve has been the preferred operative technique for reinnervation and restoration of biceps muscle function. In the current study the authors examine the efficacy of an alternative technique using median nerve fascicles transferred to the musculocutaneous nerve to reinnervate the biceps muscle.

Methods

Forty consecutive patients with combined C5–6 brachial plexus root avulsions were evaluated pre- and postoperatively according to the British Medical Research Council Motor Grading Scale. Personal interviews concerning quality of life (QOL) after surgery were conducted and scored based on standards set by the World Health Organization. All patients showed some degree of improvement in biceps muscle function. Thirty-six (90%) of the 40 patients regained movement against gravity. The patients had a 77% improvement in overall QOL after the surgery; most notably, 92% of the patients reported their lack of need for medication and 75% a significant lessening of postoperative pain. Redirection of part of the healthy median nerve resulted in no measurable functional deficits, and only 28 patients reported minor sensory disturbances in the first web space for an average of 3 months after surgery.

Conclusions

Median nerve fascicle transfer resulted in a significant improvement in biceps muscle function with an acceptable level of morbidity and should be considered an effective, and in many cases preferable, alternative to ulnar nerve fascicle transfer.

Quantitation of the lower subscapular nerve for potential use in neurotization procedures

Object

New information regarding nerve branches of the brachial plexus can be useful to the surgeon performing neurotization procedures following patient injury. Nerves in the vicinity of the axillae have been commonly used for neural grafting procedures, with the exception of the lower subscapular nerve (LSN).

Methods

The authors dissected and measured the LSN in 47 upper extremities (left and right sides) obtained in 27 adult cadavers, and determined distances between the LSN and surrounding nerves to help quantify it for possible use in neurotization procedures.

The mean diameter of the LSN was 2.3 mm. The mean length of the LSN from its origin at the posterior cord until it branched to the subscapularis muscle was 3.5 cm, and the mean distance from this branch until its termination in the teres major muscle was 6 cm. Therefore, the mean length of the entire LSN from the posterior cord to the teres major was 9.5 cm.

When the LSN was mobilized to explore its possible use in neurotization, it reached the entrance site of the musculocutaneous nerve into the coracobrachialis muscle in all but three sides and was within 1.5 cm from this point in these three. In the other specimens, the mean length of the LSN distal to this site of the musculocutaneous nerve was 2 cm. The mobilized LSN reached the axillary nerve trunk as it entered the quadrangular space in all specimens. The mean length of the LSN distal to this point on the axillary nerve was 2.5 cm. Furthermore, on all but one side the LSN was found within the confines of an anatomical triangle previously described by the authors.

Conclusions

The authors hope that these data will prove useful to the surgeon for both identifying the LSN and planning for potential neurotization procedures of the brachial plexus.

Quantitative assessment of the ability of collateral sprouting of the motor and primary sensory neurons after the end-to-side neurorrhaphy of the rat musculocutaneous nerve with the ulnar nerve

In view of the Lack of theoretical information, end-to-side neurorrhaphy is a frequent object of experimental interest. End-to-side neurorrhaphy is based on collateral sprouting of an intact axon. The quantitative assessment of collateral sprouts sent by an intact motor and sensory axon was the goal of the present study. End-to-side neurorrhaphy of the distal stump of transected musculocutaneous nerve (MCN) with intact ulnar nerve (UN) was performed in a rat model. Collateral sprouts were quantitatively evaluated by counting of motoneurons and DRG neurons following their retrograde labeling by Fluoro-Ruby and Fluoro-Emerald applied to the UN and MCN, respectively. The results suggest a comparable capacity of both intact sensory and motor axons to send collateral sprouts into a denervated nerve stump. The ratio of sensory/motor neurons, the axons of which reinnervated distal MCN stumps, was very similar to that of intact UN (6.500 and 6.747, respectively), but different from intact MCN (5.029). This suggests that the pruning process occurred to balance the collateral sprouts at a ratio of sensory/motor neurons for the donor UN, but not according to the number of sensory and motor bands of Bungner available in the distal stump of the MCN. The present experimental study confirms end-to-side neurorrhaphy as a suitable method of nerve reconstruction.

Neuronal survival, regeneration and musclemorphology after posterior C7 nerve transfer:An experimental study

C7 nerve transfer has been widely used in treating brachial plexus avulsion injuries. Little is known regarding the survival and regeneration of C7 motor and sensory neurons including their morphological changes after this procedure and also the possible change of muscle fibre phenotype. In this experimental study, the posterior division of C7 nerve was transferred to the musculocutaneous nerve ipsilaterally, and using fluorescent tracing techniques, the C7 spinal cord segment and dorsal root ganglion were found to contain 630.9 +/- 86.7 motor neurons and 3916.0 +/- 517.3 sensory neurons, respectively. Six months following transfer, 90% of the motor neurons and 78% of the sensory neurons survived and approximately 40% of them had regenerated and all displayed normal soma size. After posterior C7 transfer and reinnervation, the target muscles showed a percentage pattern of distribution and mean fibre diameters similar to those seen in normal biceps muscle. The present study suggests that the posterior C7 nerve transfer provides sufficient number of neurons and satisfactory results for regeneration to obtain an acceptable functional recovery.

[Clinical comparison of vascularized and non-vascularized full-length phrenic nerve]

OBJECTIVE

To investigate the clinical effect of vascularized and non-vascularized full-length phrenic nerve transfer on treating brachial plexus injury.

METHODS

From August 1999 to March 2000, full-length phrenic nerve transfer to musculocutaneous nerve was conducted with the technique of Video-Assisted-Thoracic-Surgery in 15 patients (M 13, F 2) that all suffered from avulsion. Three kinds of procedures were carried out. The first was retaining initial point of phrenic nerve and dissecting full-length distal nerve (group A). The second was keeping cervical segment and isolating thoracic segment of phrenic nerve (group B). The last was vascularized phrenic nerve transfer (group C). All these phrenic nerves were sutured to musculocutaneous nerves. The results of electrophysiology and function of biceps brachii muscle were compared.

RESULTS

The length of the dissecting full-length distal nerves in group A, group B and group C compared with that of conventional operation increased by 17.8 +/- 1.1 cm, 10.2 +/- 1.0 cm and 8.8 +/- 0.5 cm respectively. There was significant difference when group A was compared with group B and group C, when group B was compared with group C. All three procedures had no significant difference and led to the same function recovery of biceps brachii muscle to grade II about 6 months later.

CONCLUSION

There is no difference in treating effect between vascularized and non-vascularized full-length phrenic nerve transfer, when the recipient bed has normal vascularity.

Restoration of elbow flexion by performing contralateral lateral thoracic and thoracodorsal nerve transfers after experimental musculocutaneous nerve transection

OBJECT

The immediate transfer of the right lateral thoracic nerve (LTN) and the thoracodorsal nerve (TDN) to the transected left musculocutaneous nerve (MCN), leading to nerve cross-neurotization, was performed in cats to evaluate reinnervation of the biceps brachii muscle (BBM).

METHODS

Surgery to produce cross-neurotization of the MCN was performed in 12 cats (treatment group). Transection of the MCN was performed without attempts at neurotization in three cats (control group). Reinnervation of the BBM was assessed by performing electromyography (EMG) 6 months (14 cats) and 26 months (one cat) postsurgery. True Blue retrograde axonal tracing studies, tensile force measurements (muscle extensometry), and histopathological analyses were performed. All cats in the treatment group recovered voluntary contraction of the BBM and regained elbow flexion. Electromyography revealed no abnormal spontaneous activity in the BBM. Muscle evoked potentials were recorded in that muscle after right C-8 ventral branch stimulation. The muscle contraction strength in the left BBM varied from 108 to 557 g. The BBMs regained their normal appearances. The region of the MCN distal to the anastomosis displayed a normal histological appearance. Fluorescence was detected in the ventral horn of the spinal cord in the right C-8 and T-1 segments. In contrast, in all cats in the control group there was atrophy of the BBM, no EMG signal, and no clinical sign of recovery. There was no contraction of the BBM, no labeled neuron in the spinal cord, and the MCN displayed major degenerative changes.

CONCLUSIONS

These findings demonstrate that the LTN and TDN can be used to neurotize injured contralateral brachial plexus nerves and obtain successful reinnervation in cats.

Traumatic musculocutaneous neuropathy: a case report

Isolated injury of the musculocutaneous nerve is a rare disorder. Reported cases are claimed to present with loss of biceps and brachialis power without a disturbing pain. The injury generally occurs after strenuous exercise and could be demonstrated by electrophysiological examination. We report a case of musculocutaneous nerve injury which occurred after a vigorous push and which presented with unusual symptoms and findings. The patient complained of episodic severe pain attacks which started from the axilla and radiated over the musculocutaneous nerve distribution including the lateral antebrachial cutaneous nerve area. He did not respond to 3 months of conservative treatment including multiple corticosteroid injections and finally required surgical release. Surgical epineurotomy resulted in immediate relief. This is the first reported case of acute musculocutaneous nerve injury presenting with unusual symptoms and findings. The operative release procedure performed was also not required in any of the other reported cases. An excellent result was obtained with epineurotomy.

The use of thoracodorsal nerve transfer in restoration of irreparable C5 and C6 spinal nerve lesions

There are only a few reports on the use of thoracodorsal nerve (TDN) transfer to the musculocutaneous or axillary nerves in cases of directly irreparable brachial plexus injuries. In this study, we analysed outcome and time-course of recovery in correlation with recipient nerves and type of nerve transfer (isolated or in combination with other collateral branches) for 27 patients with transfer to the musculocutaneous or axillary nerves. Using this nerve as donor, we obtained useful functional recovery in all 12 cases for the musculocutaneous nerve, and in 14 (93.3%) of 15 nerve transfers for the axillary nerve. Although, we found no significant statistical difference between analysed patients according to the percentage of recoveries and mean values, we established a better quality and shorter time of recovery for the musculocutaneous nerve. According to obtained results, we consider that transfer may be a valuable method in reconstruction after directly irreparable C5 and C6 spinal nerve lesions.

Analysis of activity of motor units in the biceps brachii muscle after intercostal-musculocutaneous nerve transfer

We examined respiratory activity of motor units (MUs) in the internal intercostal nerves (IICNs)-transferred biceps brachii muscle (IC-biceps) in cats. MUs of IC-biceps showed respiratory discharges in inspiratory and expiratory phases, and these were enhanced by CO2 inhalation. Narrowing the airway also enhanced inspiratory and expiratory MUs activity. A mechanical load to the thorax immediately enhanced inspiratory MUs activity and weakened expiratory MUs activity. We analyzed the cross-correlation of MUs activity in interchondral muscle and IC-biceps to characterize the respiratory spinal descending inputs to motoneurons. We confirmed the short-term synchronization from interchondral muscles indicating divergence of a single respiratory presynaptic axon to thoracic motoneurons, but could not find synchronization from IC-biceps. The motor axonal conduction velocity (axonal CV) of IC-biceps MUs was lower than that of interchondral muscles. There was no correlation between the respiratory recruitment order of IC-biceps MUs and their axonal CV. These results indicate that IC-biceps shows the respiratory activities and afferent inputs from intercostal muscle spindles in the neighboring segments remain influential on activity of IC-biceps. In addition, the short-term synchronization from IC-biceps could not be found, suggesting that the intercostal nerve transfer alters the respiratory spinal descending inputs to thoracic motoneurons.

Innervation of biceps brachii and brachialis: Anatomical and surgical approach

This study describes the anatomy of the musculocutaneous nerve (MCN) in the middle and lower thirds of the arm, with special reference to the motor branches to the biceps and brachialis muscles, given their importance in certain clinical, particularly surgical, procedures. In each dissection (46 upper limbs) we recorded the course of the MCN and its variations, and the number, type of distribution pattern and length of the motor branches to the biceps brachii and brachialis muscles. We also recorded the position at which those branches arose from the MCN trunk. We found three branching patterns for biceps brachii: 1) one branch (60.5%); 2) two branches, one for each biceps head (27.9%); and 3) two branches, one for the two biceps heads and one for the common belly (11.6%). The mean distance between the acromion and the motor branches to biceps brachii was 133.8 mm, 45.3% of the acromion-lateral epicondyle distance. The mean length of those branches was 31.2 mm. We found two branching patterns for brachialis: 1) one branch (72.1%); and 2) two branches (27.9%). These motor nerves to brachialis arose from the MCN at a mean distance of 185.3 mm, 61.5% of the acromion-lateral epicondyle distance, and their average length was 33.0 mm. The data were expressed as the percentage of the distance between the acromion and the lateral epicondyle of the humerus, to make their clinical use easy and to avoid errors caused by anthropometric differences.

[Aanalysis of the brachial plexus traumatic lesions reconstructive procedures unfavourable results]

AIM

The aim of this study is to analyze unfavourable results of nerve transfers to the musculocutaneous nerve, using upper intercostal nerves.

METHODOLOGY

The trial group included 7 patients with traction injuries of the brachial plexus, who were treated surgically, using intercostal nerves as nerve transfers. The follow-up period was at least 3 years. The analysis of the motor function recovery depended on the respective patient's age and the operation time.

RESULTS

In not a single case a functional recovery of the musculocutaneous nerve was achieved.

CONCLUSION

The time gap between the injury and the operation, the level and the extent of the nerve injury and the type of the reconstructive procedure, all the above are the main prognostic factors for the functional recovery of the paralyzed muscles, resulting from its traction injury.

Contralateral motor rootlets and ipsilateral nerve transfers in brachial plexus reconstruction

Object. The goal of this study was to evaluate outcomes in patients with brachial plexus avulsion injuries who underwent contralateral motor rootlet and ipsilateral nerve transfers to reconstruct shoulder abduction/external rotation and elbow flexion.

Methods. Within 6 months after the injury, 24 patients with a mean age of 21 years underwent surgery in which the contralateral C-7 motor rootlet was transferred to the suprascapular nerve by using sural nerve grafts. The biceps motor branch or the musculocutaneous nerve was repaired either by an ulnar nerve fascicular transfer or by transfer of the 11th cranial nerve or the phrenic nerve. The mean recovery in abduction was 90° and 92° in external rotation. In cases of total palsy, only two patients recovered external rotation and in those cases mean external rotation was 70°. Elbow flexion was achieved in all cases. In cases of ulnar nerve transfer, the muscle scores were M5 in one patient, M4 in six patients, and M3+ in five patients. Elbow flexion repair involving the use of the 11th cranial nerve resulted in a score of M3+ in five patients and M4 in two patients. After surgery involving the phrenic nerve, two patients received a score of M3+ and two a score of M4. Results were clearly better in patients with partial lesions and in those who were shorter than 170 cm (p < 0.01). The length of the graft used in motor rootlet transfers affected only the recovery of external rotation. There was no permanent injury at the donor sites.

Conclusions. Motor rootlet transfer represents a reliable and potent neurotizer that allows the reconstruction of abduction and external rotation in partial injuries.

Painful entrapment of the lateral antebrachial cutaneous nerve at the elbow

PURPOSE

The purpose of this study was to report the diagnosis and management of entrapment neuropathy of the lateral antebrachial cutaneous nerve (LABCN) presenting as lateral elbow pain.

METHODS

Twenty-three patients with lateral elbow pain were diagnosed with entrapment of the LABCN. Six patients also had paresthesia of the distal forearm. Diagnosis was made by clinical evaluation and confirmed with diagnostic injection of 1% lidocaine. Electrodiagnostic evaluation was positive in all patients. All patients were treated conservatively. Seven patients improved and 16 patients had surgical decompression of the LABCN at the elbow and distal arm with partial resection of the lateral margin of the biceps tendon. Postoperative follow-up evaluation averaged 45 months.

RESULTS

Fourteen patients had complete relief of pain and 2 patients continued to have minimal to mild pain. Of the 6 patients who had preoperative paresthesia only 1 patient had persistent mild paresthesia of the radial side of the distal forearm. Range of motion and grip and pinch strength returned to normal values. All patients returned to their preoperative daily and work activities.

CONCLUSIONS

Entrapment neuropathy of the LABCN should be considered in the differential diagnosis of elbow pain. Electrodiagnostic evaluation can be very useful in establishing and confirming the diagnosis. Surgical treatment of patients who do not respond to conservative treatment is simple yet effective in improving the patients' symptoms. Patients who present with paresthesia usually require surgical intervention because paresthesia represents a more progressive stage of the nerve entrapment.

Painful neuroma of the posterior cutaneous nerve of the forearm after surgery for lateral humeral epicondylitis

PURPOSE

To describe a neuroma of the posterior cutaneous nerve of the forearm that can be the source of pain after surgery for lateral humeral epicondylitis.

METHODS

A retrospective chart review of 9 patients having pain after surgery for lateral humeral epicondylitis was conducted to evaluate their history of pain, surgical findings during exploration of their painful lateral elbow scar, and outcome of their surgical treatment.

RESULTS

In each of the 9 patients a neuroma of the posterior cutaneous nerve of the forearm was found to be within the scar of the original lateral epicondylitis surgery. For each of these patients the surgical treatment included resection of the neuroma and implantation of the proximal end of the nerve into the brachioradialis muscle proximal to the elbow joint. With this approach 8 of the patients had excellent pain relief and 1 had good pain relief at a mean follow-up time of 1.4 years (range, 1.0-2.6 years).

CONCLUSIONS

Pain in the region of the scar after surgery to treat lateral humeral epicondylitis can be caused by a neuroma of the posterior cutaneous nerve of the forearm and this painful neuroma can be treated successfully by neuroma resection and implantation of the nerve proximally into the brachioradialis muscle.

Comparative experimental study on treatment outcome of nerve transfer, using selective C7 nerve root vs. phrenic nerve

The treatment outcome of nerve transfer using the C7 nerve root or phrenic nerve was compared in a rat experiment. One hundred and twenty SD rats were divided into two groups, one undergoing phrenic nerve transfer to the musculocutaneous nerve, and the other partial ipsilateral C7 (anteriolateral fascicles of the anterior division) to the musculocutaneous nerve. Neurotization outcomes of the two groups were evaluated by comparing the electrophysiologic, histologic, and myophysiologic changes of the biceps muscle. No significant differences were found between parameters from the phrenic nerve transfer group and those from the ipsilateral C7 nerve transfer group. This indicates that the treatment outcome of selective ipsilateral C7 transfer is comparable to that of phrenic nerve transfer. It is the surgery of choice in treating brachial plexus upper-trunk avulsion accompanied by phrenic nerve injury.

Transfer of pectoral nerves to the musculocutaneous nerve in obstetric upper brachial plexus palsy

OBJECTIVE

To investigate the results of transfer of pectoral nerves to the musculocutaneous nerve for treatment of obstetric brachial palsy.

METHODS

In 25 cases of obstetric brachial palsy (20 after breech deliveries), branches of the pectoral nerve plexus were transferred directly to the musculocutaneous nerve. For all patients, the nerve transfer was part of an extended brachial plexus reconstruction. Results were tested both clinically and with the Mallet scale, at a mean follow-up time of 70 months (standard deviation, 34.3 mo).

RESULTS

There were two complete failures, which were attributable to disconnection of the transferred nerve endings. The results after transfer were excellent in 17 cases and fair in 5 cases. Steindler flexorplasty improved elbow flexion for three patients.

CONCLUSION

Transfer of pectoral nerves to the musculocutaneous nerve for treatment of obstetric upper brachial palsy may be effective, if the specific anatomic features of the pectoral nerve plexus are sufficiently appreciated.

Re-innervation of M. biceps by end-to-side nerve suture

End-to-side nerve suture (ETSNS) is a viable option to re-innervate a paralysed biceps muscle. The host or donor nerve could be any of the adjacent large nerves including the brachial plexus. It is important to adhere to certain principles when performing ETSNS, e.g. epineural window only, suture line without tension, the recipient nerve should not "kink" in any way and complete immobilisation for at least three weeks. The earlier this ETSNS is done after injury the better the outcome. Patient co-operation and motivation is of the utmost importance. The post-operative rehabilitation programme is essential to "awaken" and strengthen the dormant muscle. Our results are based on five patients. Good elbow flexion, i.e. biceps contraction can be regained after ETSNS of, for example, the musculo-cutaneous nerve into an appropriate viable host nerve.

Brachial plexus injury: factors affecting functional outcome in spinal accessory nerve transfer for the restoration of elbow flexion

OBJECT

Between 1994 and 1998, 44 nerve transfers were performed using a graft between a branch of the accessory nerve and musculocutaneous nerve to restore the flexion of the arm in patients with traumatic brachial plexus injuries. A retrospective study was conducted, including statistical evaluation of the following pre- and intraoperative parameters in 39 patients: 1) time interval between injury and surgery; and 2) length of the nerve graft used to connect the accessory and musculocutaneous nerves.

METHODS

The postoperative follow-up interval ranged from 23 to 84 months, with a mean +/- standard deviation of 36 +/- 13 months. Reinnervation of the biceps muscle was achieved in 72% of the patients. Reinnervation of the musculocutaneous nerve was demonstrated in 86% of the patients who had undergone surgery within the first 6 months after injury, in 65% of the patients who had undergone surgery between 7 and 12 months after injury, and in only 50% of the patients who had undergone surgery 12 months after injury. A statistical comparison of the different preoperative time intervals (0-6 months compared with 7-12 months) showed a significantly better outcome in patients treated with early surgery (p < 0.05). An analysis of the impact of the length of the interposed nerve grafts revealed a statistically significant better outcome in patients with grafts 12 cm or shorter compared with that in patients with grafts longer than 12 cm (p < 0.005).

CONCLUSIONS

Together, these results demonstrated that outcome in patients who undergo accessory to musculocutaneous nerve neurotization for restoration of elbow flexion following brachial plexus injury is greatly dependent on the time interval between trauma and surgery and on the length of the nerve graft used.

Functional magnetic resonance imaging and control over the biceps muscle after intercostal-musculocutaneous nerve transfer

OBJECT

Recent progress in the understanding of cerebral plastic changes that occur after an intercostal nerve (ICN)-musculocutaneous nerve (MCN) transfer motivated a study with functional magnetic resonance (fMR) imaging to map reorganization in the primary motor cortex.

METHODS

Eleven patients with traumatic root avulsions of the brachial plexus were studied. Nine patients underwent ICN-MCN transfer to restore biceps function and two patients were studied prior to surgery. The biceps muscle recovered well in seven patients who had undergone surgery and remained paralytic in the other two patients. Maps of neural activity within the motor cortex were generated for both arms in each patient by using fMR imaging, and the active pixels were counted. The motor task consisted of biceps muscle contraction. Patients with a paralytic biceps were asked to contract this muscle virtually. The location and intensity of motor activation of the seven surgically treated arms that required good biceps muscle function were compared with those of the four arms with a paralytic biceps and with activity obtained in the contralateral hemisphere regulating the control arms. Activity could be induced in the seven surgically treated patients whose biceps muscles had regained function and was localized within the primary motor area. In contrast, activity could not be induced in the four patients whose biceps muscles were paralytic. Neither the number of active pixels nor the mean value of their activations differed between the seven arms with good biceps function and control arms. The weighted center of gravity of the distribution of activity also did not appear to differ.

CONCLUSIONS

Reactivation of the neural input activity for volitional biceps control after ICN-MCN transfer, as reflected on fMR images, is induced by successful biceps muscle reinnervation. In addition, the restored input activity does not differ from the normal activity regulating biceps contraction and, therefore, has MCN acceptor qualities. After ICN-MCN transfer, cerebral activity cannot reach the biceps muscle following the normal nervous system pathway. The presence of a common input response between corticospinal neurons of the ICN donor and the MCN acceptor seems crucial to obtain a functional result after transfer. It may even be the case that a common input response between donor and acceptor needs to be present in all types of nerve transfer to become functionally effective.

Cortical reorganization in training

Plasticity within the human central motor system occurs and has been studied with transcranial magnetic stimulation in patients with amputations, spinal cord injuries, and ischemic nerve block. These studies have identified a pattern of motor system reorganization that results in enlarged muscle representation areas and large motor evoked potentials (MEPs) for muscles immediately proximal to the lesion. Some of these changes are apparent minutes after ischemic nerve block, weeks after spinal cord injury, and as early as six months after amputation.These studies motivated us to study the cortical motor reorganization after finger movement training in normals and after anastomosis of intercostal nerves to the musculocutaneous nerve in young patients with cervical root avulsions due to a traumatic motorcycle injury.

Nerve transfers to the biceps and brachialis branches to improve elbow flexion strength after brachial plexus injuries

OBJECT

In this study the authors evaluated the outcome in patients with brachial plexus injuries who underwent nerve transfers to the biceps and the brachialis branches of the musculocutaneous nerve.

METHODS

The charts of eight patients who underwent an ulnar nerve fascicle transfer to the biceps branch of the musculocutaneous nerve and a separate transfer to the brachialis branch were retrospectively reviewed. Outcome was assessed using the Medical Research Council (MRC) grade to classify elbow flexion strength in conjunction with electromyography (EMG). The mean patient age was 26.4 years (range 16-45 years) and the mean time from injury to surgery was 3.8 months (range 2.5-7.5 months). Recovery of elbow flexion was MRC Grade 4 in five patients, and Grade 4+ in three. Reinnervation of both the biceps and brachialis muscles was confirmed on EMG studies. Ulnar nerve function was not downgraded in any patient.

CONCLUSIONS

The use of nerve transfers to reinnervate the biceps and brachialis muscle provides excellent elbow flexion strength in patients with brachial plexus nerve injuries.

Full-length phrenic nerve transfer by means of video-assisted thoracic surgery in treating brachial plexus avulsion injury

Phrenic nerve transfer has been widely used in treating brachial plexus avulsion injury. However, the present method crosses the thoracic part of the phrenic nerve, and nerve graft is needed, resulting in a long period of regeneration and partly irreversible muscle atrophy. We present our early experience of using video-assisted thoracic surgery to harvest a full length of phrenic nerve for transfer. Fifteen patients (mean age, 28 years) were treated. The thoracic part of the phrenic nerve was freed by means of video-assisted thoracic surgery and taken out of the thoracic cavity, and a full-length phrenic nerve was transferred to the musculocutaneous nerve to recover elbow flexion. The patients were followed. Another 29 patients with long-term follow-up who underwent traditional cervical phrenic nerve to musculocutaneous nerve transfer in our institute between 1994 and 1997 were selected. The period of newborn potential appearing in the biceps and the period for biceps to achieve M3 between two groups were compared. The operation was safe and no complications occurred. The additional length of phrenic nerve was 12.3 +/- 4.5 cm. Eleven patients received sufficient follow-up. Eight patients achieved biceps recovery to M3 (elbow flexion against gravity), and mean time was 198.8 +/- 36.0 days, much earlier than that of the traditional method (p < 0.01). Pulmonary function recovered to the preoperative level 9 months after operation. This new method is safe and minimally invasive. The result of full-length phrenic nerve transfer is much better than that of the traditional method. It obviously shortens the time required for nerve reinnervation, and offers a promising method for patients who have had a long interval from injury to operation and for forearm muscle reconstruction by phrenic nerve transferred to the median nerve or combined with free-muscle transfer.

Patient outcome following a thoracodorsal to musculocutaneous nerve transfer for reconstruction of elbow flexion

This study reports patient outcome following a thoracodorsal to musculocutaneous nerve transfer. We retrospectively reviewed the charts of six patients who had undergone transfer of the thoracodorsal nerve to the musculocutaneous nerve for reconstruction of elbow flexion. The mean age was 47 years (standard deviation: 24 years; range: 17-72 years). The mean time from injury to surgery was 3 months (standard deviation: 2 months; range: 1-5 months). In all cases, the biceps muscle was successfully reinnervated; in one case the Medical Research Council (MRC) muscle grade was grade 5, in four cases it was grade 4, and in one case it was grade 2. No patients complained of functional weakness with shoulder adduction and/or internal rotation. In the majority of cases, transfer of the thoracodorsal nerve to the musculocutaneous nerve provides excellent recovery of elbow flexion.

Transfer of the medial pectoral nerve: myth or reality?

OBJECTIVE

Transfer of the medial pectoral nerve is one of the most controversial procedures used to reinnervate the paralyzed upper arm because of brachial plexus spinal nerve root avulsion or directly irreparable proximal lesions of spinal nerves. The purpose of this study was to determine the value of this type of nerve transfer to the musculocutaneous and axillary nerves.

METHODS

The 25 patients included in the study comprised 14 patients who had nerve transfer to the musculocutaneous nerve and 11 who underwent nerve transfer to the axillary nerve. These patients' functional recovery and the time course of their recovery were analyzed according to the type of transfer of one donor nerve or the donor nerve in combination with other donors.

RESULTS

Useful functional recovery was achieved in 85.7% of patients who had nerve transfer to the musculocutaneous nerve and in 81.8% of patients who underwent nerve transfer to the axillary nerve. There was no significant difference in results with regard to the type of nerve transfer and which recipient nerves were involved. A strong trend toward better results after procedures involving the use of a donor nerve combined with other donors was observed, however.

CONCLUSION

Our surgical results suggest that the transfer of the medial pectoral nerve to the musculocutaneous nerve and also to the axillary nerve may be a reliable and effective procedure.

Muscle preservation by prolonged sensory protection

The functional recovery of a muscle target following nerve repair is inversely related to the denervation time: i.e., the longer the muscle denervation, the poorer the functional outcome following nerve reconstruction. The trophic and protective effects of sensory innervation to a motor nerve, following prolonged denervation (greater than 6 months), have been studied. Following proximal transection of the musculocutaneous nerve (MC) close to its C6 origin in 10 adult male Sprague-Dawley rats, the severed nerve was coapted to supraclavicular purely sensory nerves originating from C3 and C4 (sensory protection [SP] group). In another 10 Sprague-Dawley rats, the transected MC nerve was not protected by coaptation to sensory nerves (control group). After prolonged denervation or "sensory protection" (6 months), the MC nerve was then coapted in both groups to the purely motor medial pectoral nerve. Behavioral testing (grooming test) was performed on a weekly basis during the reinnervation time, which lasted 4 weeks. Statistically significant differences (p<0.05) favoring the SP group, were found at the second week of the reinnervation period, but not at the end of the experiment. Evaluation also included intraoperative electrical stimulation of the MC nerve, biceps muscle dry weights, motor endplate counts, and nerve axon counts of the MC nerve. The biceps muscle dry weights were statistically higher in the SP group, along with a trend for a higher number of motor endplates. No statistically significant difference was found in the nerve axon counts of the MC nerve between the two groups. Statistically better intraoperative electrical stimulation results were also encountered in the sensory protection group. An interpretation of the results favors the hypothesis that sensory reinnervation of a motor target may provide the necessary trophic environment to minimize muscle atrophy, until a motor donor nerve becomes available.

Surgical treatment of painful neuroma in medial antebrachial cutaneous nerve

The branches of the medial antebrachial cutaneous nerve (MACN) are located at the medial site of the elbow. The MACN, especially the posterior branches, may be injured or transected during cubital tunnel surgery or other medial approaches to the elbow. Damage to the nerve can cause a neuroma, which leads to disabling pain and restriction of elbow movement. The initial treatment of the neuroma is nonsurgical, and includes local massage, desensitization, physiotherapy, and systemic medication. If after 6 months of these nonsurgical treatments there is no improvement, surgery is indicated. The authors report their experience with 12 patients treated surgically for painful neuroma by high resection of the proximal end or its implantation into the triceps muscle. After surgery there was a high success rate of pain relief and functional improvement in both elbow movement and handgrip strength.

Physiologic and morphologic aspects of nerve regeneration after end-to-end or end-to-side coaptation in a rat model of brachial plexus injury

The results of repairing a transected rat musculocutaneous nerve by suturing the distal stump, end to side or end to end, to the ipsilateral ulnar nerve were assessed at 3 months by retrograde labeling and morphologic and physiologic analysis. Unlike most other models of end-to-side repair in which the injured recipient and donor reinnervating nerves have overlapping neuron pools in the spinal cord, in this model the neurons of the injured musculocutaneous and the reinnervating ulnar nerves are located in mutually exclusive segments of the spinal cord. Using retrograde labeling we show that the reinnervating fibers are derived solely from the ulnar nerve pool. Both end-to-side and end-to-end coaptation resulted in reinnervation of the distal musculocutaneous nerve and significant functional reinnervation of its dependent biceps brachii muscle. Although end-to-end coaptation resulted in better axon morphology and muscle function, it resulted in total loss of donor nerve function. By contrast, end-to-side coaptation resulted in good recovery with only minimal donor nerve deficit. These results show that significant functional reinnervation of biceps brachii muscle can occur solely on the basis of collateral sprouting of intact axons from the adjacent ulnar nerve.

Intercostal nerve transfer classification

We report a new classification of intercostal nerve transfer. The specific application in brachial plexus reconstruction is described. This method was applied in intercostal nerve transfer to the musculocutaneous nerve in 15 patients. In type 1, "MOTOR to MIXED" transfer one harvest only the intercostal main motor branch which is connected at the trunk of the musculocutaneous nerve, without fascicular specificity. In type 2, "MIXED to MIXED" transfer, based on neural cartography, the main motor branch and its sensitive accessory anterior branches are connected to the musculocutaneous nerve trunk, in attempt to connect the motor fascicules together at the center and also the sensory fascicules together, at the circumference. In type 3, "MOTOR to MOTOR" transfer, the intercostal main motor branch is connected to the musculocutaneous motor branch directly destined to the biceps brachialis. The aim of this work is to evaluate the results between different series.

Use of intercostal nerves for neurotization of the musculocutaneous nerve in infants with birth-related brachial plexus palsy

OBJECT

The use of intercostal nerves (ICNs) for the neurotization of the musculocutaneous nerve (MCN) in adult patients with traumatic brachial plexus palsy has been well described. However, its use for brachial plexus palsy in infants has rarely been reported. The authors surgically created 31 ICN-MCN communications for birth-related brachial plexus palsy and present the surgical results.

METHODS

Thirty-one neurotizations of the MCN, performed using ICNs, were conducted in 30 patients with birth-related brachial plexus palsy. In most cases other procedures were combined to reconstruct all upper-extremity function. The mean patient age at surgery was 5.8 months and the mean follow-up period was 5.2 years. Intercostal nerves were transected 1 cm distal to the mammary line and their stumps were transferred to the axilla, where they were coapted directly to the MCN. Two ICNs were used in 26 cases and three ICNs in five cases. The power of the biceps muscle of the arm was rated Grade M4 in 26 (84%) of 31 patients. In the 12 patients who underwent surgery when they were younger than 5 months of age, all exhibited a grade of M4 (100%) in their biceps muscle power. These results are better than those previously reported in adults.

CONCLUSIONS

Neurotization of the MCN by surgically connecting ICNs is a safe, reliable, and effective procedure for reconstruction of the brachial plexus in patients suffering from birth-related palsy.

Entrapment of the lateral antebrachial cutaneous nerve exiting through the forearm fascia

Isolated lateral antebrachial cutaneous nerve entrapment syndromes are uncommon. This report describes the compression of the lateral antebrachial cutaneous nerve of the forearm at the level of its passage through the superficial antebrachial fascia, distal to the elbow crease. Numbness and a painful dysesthesia over the radial aspect of the volar forearm were documented. Failure of conservative treatment necessitated surgical decompression.

Surgical relationship of the medial pectoral nerve to the musculocutaneous nerve: a cadaveric study

OBJECTIVE

For purposes of neurotization of the musculocutaneous nerve (MCN) with the medial pectoral nerve (MPN) after upper trunk brachial plexus injuries, the anatomic relationship between these two nerves was defined in a cadaveric model.

METHODS

Thirty-five brachial plexuses in 18 adult cadavers were dissected. The distance between the origin of the MPN from the medial cord to the origin of the MCN from the lateral cord was measured. The length, diameter, branching, and location of the MPN were recorded. The diameter of the proximal MCN was recorded.

RESULTS

Thirty-seven percent of the MPNs, when detached from the pectoralis muscles, were too short to reach the proximal MCN by a mean distance of 15 mm. The MPN pierced the pectoralis minor muscle in 80% of the dissections. The cross sectional area of the MCN was always larger than the cross sectional area of the MPN by an average factor of 2.5.

CONCLUSION

When planning to use the MPN for neurotization of the MCN, one should be prepared to harvest an interposition graft, because over one-third of MPNs may not have enough length to reach the MCN in a tension-free manner. Diameter mismatch occurs predictably between the distal MPN and the proximal MCN.

The musculocutaneous nerve

We have analysed the results of repair of traumatic lesions of the musculocutaneous nerve in 85 patients, which were graded by Seddon's modification of the Medical Research Council system into three types of injury: open 'tidy', open 'untidy' and closed 'traction'. They were also correlated with associated arterial injury. There were 57 good, 17 fair and 11 poor results. The type of injury was the most important factor in determining the result; 12 of 13 open-tidy lesions gave good results compared with 30 of 48 closed-traction lesions. The results were better when the nerves were repaired within 14 days of injury and when grafts were less than 10 cm long. They were worse in the presence of associated arterial or bony injury.

Role of the target in end-to-side neurorrhaphy: reinnervation of a single muscle vs. multiple muscles

The authors examined the effects of end-to-side neurorrhaphy for reinnervation of the musculocutaneous nerve (Group A) which innervates the biceps muscle, compared to reinnervation of the median nerve which innervates multiple muscles in a rat model. Additionally, end-to-end neurorrhaphy to the musculocutaneous nerve using one-third of the median nerve (Group B) was investigated. End-to-end coaptation of the musculocutaneous nerve served as a control (Group C). In a grooming test, the biceps muscle function in Group A animals demonstrated a slower but nearly similar good recovery to Groups B and C. Biceps muscle contraction force investigated after 24 weeks demonstrated no statistically significant differences among all groups. In Groups A and B, no significant impairment of the donor median nerve function was found in a grasping test and the muscle contraction force of the flexor carpi radialis muscle, and histologic evaluation of the musculocutaneous nerve showed multiple regenerated axons distal to the coaptation site. Retrograde double-labeling in Group A animals showed reinnervation of the musculocutaneous nerve by median nerve axons located at the coaptation site. These results validate that end-to-side neurorrhaphy to a nerve innervating a single muscle is more efficient than to a nerve innervating multiple muscles, as demonstrated in an earlier study. The reason for this phenomenon is most likely that all sprouting axons are directed toward one target rather than toward multiple targets, with the latter situation resulting in a smaller number of axons and a variable distribution of axons per target. Since donor nerve sprouting axons were observed at the coaptation site, a relevance of the selected site for end-to-side neurorrhaphy is suggested. Both end-to-side neurorrhaphy and end-to-end neurorrhaphy, using one-third of the median nerve, led to useful functional recovery in this rat model, if an agonistic donor nerve is employed.