Purpose: The purpose of this study was to establish the map of the motor branches of the median and ulnar nerves of the forearm and to count the Martin-Gruber anastomoses. Knowledge of anatomic variability would be useful for hyponeurotisation surgery of the spastic hand. Variations in the antebrachial emergence of the six motor branches of the medial nerve and the three motor branches of the ulnar nerve were studied. Material and methods: This study was conducted on twenty anatomic specimens obtained from five men and five women. We measured the length of the forearm and identified the origin of each motor branch of the medial and ulnar nerves using a horizontal line between the meidal and lateral epicondyles as the reference line. Results: Mean length of the forearm was 26.93±2.6 cm. Unlike the origin of the superior and inferior pronator teres nerves, and the palmaris longus, flexor carpi radialis, and flexor digitorum superficialis nerves which were very variable (coefficient of variation 49%–113%), the origin of the anterior interosseous nerve of the forearm (CV=39%) and its branches, and the flexor pollicis longus nerve and the flexor digitorum profondus nerves (CV =23% and 29% respectively) were much more regular. The superior and inferior origins of the flexor carpi ulnaris nerve were variable (CV = 157 and 22%) while the origin of the nerves for the deep flexor of the IV and V fingers showed a better coefficient of variation (13%). We observed four Martin-Gruber anastomoses (20%). Conclusion: This study demonstrated the wide anatomic variability of the medial and ulnar nerves both interin-dividually and intraindividually. Emergence of certain nerve branches appeared to be more regular, particularly the lower group of the median nerve and the anterior interosseous nerve of the forearm. It was however impossible to identify two groups exhibiting a statistically significantly greater frequency for the median nerve. The anatomic variations of the ulnar nerve were less pronounced. The inconsistency of the inferior flexor carpi ulnaris is noteworthy

Aims

The sensitivity and specificity of electrodiagnostic parameters in diagnosing carpal tunnel syndrome (CTS) have been reported differently, and this study aims to address this gap.

Introduction: End-to-side nerve repair is an experimental technique for repairing peripheral nerves when severe injury renders the proximal nerve stump not available for end-to-end repair or for conventional nerve grafting techniques. This study uses a large animal model to compare two variations of end-to-side neurorrhaphy techniques with conventional clinically established methods of nerve repair to assess the feasibility of end-to-side suture as a technique for possible future clinical use. Methods: 12 age and weight matched sheep underwent end-to-side neurorrhaphy of the distal stump of the transected median nerve to the lateral side of the adjacent intact ulnar nerve through an epineurial window. 12 sheep underwent the same procedure as above but with the proximal stump of the transected median nerve similarly attached 2cm proximal to the first neurorrhaphy site to create a double end-to-side model. 18 sheep underwent conventional methods of nerve repair. All the experiments were randomized and the author performed all the surgery. The nerve repairs were assessed electrophysiologically and histologically and the muscles supplied by the repaired nerves were assessed physiologically at one-year post repair. Normal median nerves and donor ulnar nerves were also tested in the same ways. Results: There were no significant differences in the outcomes of nerve repair between different conventional techniques. Half the end-to-side repairs failed but the double end-to-side repair consistently supported nerve regeneration. Both end-to-side methods were inferior to conventional techniques of nerve repair in all measures of outcome except twitch and tetanic muscle tensions. The function of the donor ulnar nerves in terms of conduction velocity was compromised in the double end-to-side repair but not the end-to-side repair. Discussion and Conclusions: End–to-side nerve repair did support nerve regeneration but it was all or nothing. It is likely that the double end-to-side neurorrhaphies regenerated more consistently than the single end-to-side neurorrhaphies due the conduit effect of the donor ulnar nerve bridge supporting axon growth. Donor ulnar nerve damage in the double end-to-side group suggests regeneration may have occurred from terminal sprouts rather than collateral sprouts. Although end-to-side neurorrhaphy did support nerve regeneration with sometimes good return of muscle function, the use of this technique as a clinical tool at this time cannot be recommended

Aims: Multiple nerve repair by means of a Y-shaped nerve guide represents a good model for studying the specificity of peripheral nerve fiber regeneration. Here we have employed this model for investigating the specificity of axonal regeneration in mixed nerves of the rat forelimb model. Specificity of nerve regeneration can be defined as the ability of the nerve fibers of a peripheral nerve, after a lesion. Tree types of specificity on nerve regeneration has been postulated: “tissue specificity” (the preferential reinnervation of distal nerve tissue versus other types of tissue), topographic specificity (regenerating nerve fibers are preferentially attracted by analogous distal pathways (e.g. preferential regeneration along tibial nerve pathways by tibial nerve fibers), and end-organ specificity, which is the hypothesis that distal end-organs (muscle vs. sensory targets) specifically attracts the respective (motor vs. sensory) regenerating nerve fibers. Exists no agreement regarding the presence and features of the two last type of specificity. Methods: The left median and ulnar nerves, in adult female rats, were transected and repaired with a 14-mm Y-shaped conduit. The proximal end of the Y-shaped conduit was sutured to the proximal stump of either the median nerve or the ulnar nerve. Ten months after surgery, rats were tested for functional recovery of each median and ulnar nerve. Quantitative morphology of regenerated myelinated nerve fibers was then carried out by the two-dimensional disector technique. Results: Results showed that partial recovery of both median and ulnar nerve motor function was regained in all experimental groups. Performance in the grasping test was significantly lower when the ulnar nerve was used as the proximal stump. Ulnar test assessment showed no significant difference between the two Y-shaped repair groups. The number of regenerated nerve fibers was significantly higher in the median nerve irrespectively of the donor nerve, maintaining the same proportion of myelinated fibers between the two nerves (about 60% median and 40% ulnar). On the other hand, nerve fiber size and myelin thickness were significantly larger in both distal nerves when the median nerve was used as the proximal donor nerve stump. G-ratio and myelin thickness/ axon diameter ratio returned to normal values in all experimental groups. Conlusions: These results demonstrate that combined Y-shaped-tubulization repair of median and ulnar nerves permits the functional recovery of both nerves, independently from the proximal donor nerve employed, and that tissue, and not topographic, specificity guides nerve fiber regeneration in major forelimb mixed nerves of rats

Introduction The close proximity of the cutaneous and major nerves around the elbow have caused orthopaedic surgeons to feel uncomfortable about the prospect of performing basic and advanced elbow arthroscopy. The aim of this study was to review the proximity of the nerves with arthroscopic vision in a cadaveric model and selected clinical cases. Methods Open exploration of the major nerves in the elbow was performed in alcohol preserved cadaveric specimens. Arthroscopic assessment of the elbow joint was performed before and after the capsule adjacent to the nerve was excised. The arthroscopic assessment of the major nerves in these specimens provided an excellent way to visualise the nerves. Results The radial nerve was found to be in contact with the anterior capsule of the joint and was at great risk with portal placement, lateral sided procedures including synovectomy, radial head excision, capsulotmy and capsulectomy. The medial nerve was protected by the brachialis muscle. The ulnar nerve was also at risk in the medial gutter. Conclusions The close proximity of the major nerves to the elbow joint places them at risk, with elbow arthroscopy. The radial and ulnar nerves are particularly close and their exact position can be dissected free with arthroscopic techniques

Purpose: We present a 12 year follow up of a patient who presented with a multiple plexiform schwannoma of the median nerve with multiple recurrences, where it was possible to salvage the limb. Patients and Methods: Multiple plexiform Schwannomas are rare nerve sheath tumours. In this case the tumour presented as a soft non-tender swelling in the palm of a child. On exploration the lesion was found to involve the median nerve from the digital nerves to the antecubital fossa. Histology confirmed a plexiform schwannoma. The tumour was locally very aggressive with multiple recurrences initially in the median nerve and ulnar nerves and later in the nerve grafts used following excision of the primary tumour. We present a pictorial review of the mode of presentation of the tumour; discuss different modalities used for limb salvage and the differential diagnosis of this rare tumour. Conclusion: There are very few reports of PS involving main nerve trunks and none describe the long term follow-up. We report a twelve year follow up of a PS involving the main nerve trunks of the upper limb with salvage despite multiple recurrences. The clinical course of the tumour is presented up to the age of sixteen where the growth tumour appears to have regressed

Aims: We studied the ulnar nerves of five cadaveric specimens at Guyon’s canal to determine the presence, incidence and position of Renaut bodies. These are fusiform structures composed of fibroblast-like cells found within the endoneurium. Although their aetiology and role is unconfirmed, they do show a predilection for sites of nerve entrapment. Methods: Following dissection of the ulnar nerve sections were stained with toluidine blue and immunostains to demonstrate either Schwann cells, basal laminae, or axons. Fascicular topography, the number of perineurial cell layers and the number and distribution of Renaut bodies were recorded for each section. Results: Two points arise from our demonstration of a consistent appearance of Renaut bodies at the deep distal hiatus of Guyon’s canal. First, markers of subclinical nerve compression are present. Second, our results show that this subclinical compression occurs not in Guyon’s canal itself, but at its deep exit, the deep distal hiatus. Conclusion: These findings have clinical implications for the relief of Guyon’s canal syndrome. Decompression of the space alone may not be adequate. It would seem reasonable to argue that to optimise conditions for nerve recovery, the deep distal hiatus should be released as routine in all Guyon’s canal decompression procedures

Introduction and Aims: The close proximity of the major nerves to the elbow places them at risk with elbow arthroscopy. New techniques of endoscopic ulnar nerve release, biceps bursoscopy and anterior elbow arthroscopy portal will be presented. Method: In a cadaveric model needles were used to transfix the major nerves to the elbow joint capsule. From an arthroscopic perspective the needles were located to assess the position of each nerve. Capsular windows were created to provide arthroscopic visualisation of each nerve. A technique of endoscopic ulnar nerve release using the Agee system will be presented including a cadaveric study assessing its safety. Endoscopic biceps bursoscopy will also be demonstrated. Results: The ulnar nerve passes on the postero-medial capsule and is at risk with debridement of the medial gutter. The radial nerve passes on the anterior-lateral capsule and is at risk during lateral portal placement, anterior capsular release, synovectomy and radial head excision. The median nerve passes anterior to the brachialis muscle and is protected. In a cadaveric model we were able to reproducibly perform a release of the arcade of Struthers, cubital retinaculum and Osborne’s FCU fascia with no injuries to the ulnar nerve or branches. Biceps bursoscopy can be performed for partial tears of the biceps tendon. Through the biceps bed an anterior elbow arthroscopy portal can safely be created. Conclusion: An understanding of the proximity radial and ulnar nerves allows elbow arthroscopy to be more safely performed. The endoscopic ulnar nerve release, biceps bursoscopy and anterior elbow arthroscopy portal are new techniques extending the therapeutic options

Over 75% of combat casualties from Iraq and Afghanistan sustain injuries to the extremities, with 70% resulting from the effects of explosions. Damage to peripheral nerves may influence the surgical decision on limb viability in the short-term, as well as result in significant long-term disability. To date, there have been no reports of the incidence and severity of nerve injury in the current conflicts. A prospective assessment of United Kingdom (UK) Service Personnel attending a specialist nerve injury clinic was performed. For each patient the mechanism, level and severity of injury to the nerve was assessed and associated injuries were recorded. Fifty-six patients with 117 nerve injuries (median 2, range 1–5) were eligible for inclusion. This represents 12.9% of casualties sustaining an extremity injury. The most commonly injured nerves were the tibial (19%), common peroneal (16%) and ulnar nerves (16%). 25% (29) of nerve injuries were conduction block, 41% (48) axonotmesis and 34% (40) neurotmesis. The mechanism of injury did not affect the severity of injury sustained (explosion vs gunshot wound (GSW), p=0.53). An associated fracture was found in only 48% of nerve injuries and a vascular injury in 35%. The presence of an associated vascular injury resulted in more severe injuries (conduction vs axonotmesis and neurotmesis, p< 0.05). Nerves injured in association with a fracture, were more likely to develop axonotmesis (p< 0.05). The incidence of peripheral nerve injury from combat wounds is higher than previously reported. This may be related to increasing numbers of casualties surviving with complex extremity wounds. In a polytrauma situation, it may be difficult to assess a discrete peripheral neurological lesion. As only 35% of nerves injured are likely to have anatomical disruption, the presence of an intact nerve at initial surgery should not preclude the possibility of an injury. Therefore, serial examinations combined with appropriate neurophysiologic examination in the post-injury period are necessary to aid diagnosis and to allow timely surgical intervention. In addition, conduction block nerve injuries can be expected to make a full recovery. As this accounts for 25% of all nerve injuries, we recommend that the presence of an insensate extremity should not be used as an indicator for assessing limb viability

We performed a new operation for ulnar neuropathy caused by recurrent dislocation at the medial epicondyle. There were eleven patients, eight men and three women, with an average age of 52 years (24–74 years) at the time of surgery. The mean duration of symptoms was 23 months. The severity of the symptoms was McGowan grade 1 in five patients, grade 2 in five patients, and grade 3 in one patient. The operation consisted of ulnar groove plasty proximal to the cubital tunnel. The ulnar nerve was replaced into this reconstructed groove. The nerve was confirmed to be stable throughout the full range of elbow motion. The cubital tunnel retinaculum of all patients was hypoplastic and the dislocated portion of the ulnar nerves was hard. One nerve showed severe adhesion around the dislocation site. One patient had a pseudo-neuroma. All patients were relieved of discomfort, and motor and sensory function were recovered. The ulnar nerve in the groove showed neither irritation nor adhesion. In patients with grade 1, symptoms or numbness of the fingers was relieved within three months of the operation. Sensory disturbances in patients with grade 2 symptoms also improved within six months. Grade 2 patients with intrinsic muscle weakness regained normal muscular power, and these with patients with intrinsic muscle atrophy had showed increasing muscular power. The patient with grade 3 symptomes recovered normal sensation after 1 year; clawing of the ring and little fin-gers recovered, and the muscle volume was increased. Friction ulnar neuropathy has been treated traditionally by anterior transpositon or medial epicondylectomy. The ulnar nerve may become entrapped in scar tissue after these operations. We believe that this anatomical position is optimum for the nerve and that this procedure is essential for treatment of friction neuropathy

Aims: Muscle fat degeneration and fibrosis following long time denervation is today the main cause of poor functional recovery after peripheral nerve surgery especially for reconstruction of proximally located lesions of median and ulnar nerves such as those at brachial plexus level. External electro-stimulation is actually one possible way to avoid muscular atrophy and degeneration and is frequently used in the post-operative of patients with neurological palsy. A new approach that has been proposed to prevent denervation-related muscle atrophy is sensory protection performed by direct neurotization of a denervated muscle with a branch of a sensitive nerve passing nearby. The aim of this study was to study the effectiveness of sensory protection on denervated muscles as a technique to avoid their atrophic process. Methods: In four groups of rats (A,B,C and D), the median nerves were transected at right and left forearm. In group A,B and C, denervated muscles were “reinnervated” with a sensory nerve (sensory protection). Animals of group A was sacrificed after six months for a morphologic study of muscles. Animals of groups B and C were reinnervated after six months either keeping sensory protection (group B) or removing it (group C) and sacrificed after one year. Group D (without sensory protection) was reinnervated after six months and sacrificed after one year (control group). Muscle histology was performed on all samples. Functional comparison of different group was perfor-mend by means of the grasping test. Results: Histological analysis showed that sensory protection led to a better muscular trophism in all experimental groups. Also the functional testing showed better performances in sensory protected animals and especially in group C (de-protected before re-innervation) compared with group B (not de-protected before re-innervation) and D (control). Conclusions: Initial data analisys obtained in this study showed that sensory protection is effective in reducing denervation-related muscle atrophy. De-protection of the muscle before its reinnervation is also important to ameliorate post-surgical functional recovery. A new trial will be carried out with a larger number of cases in order to confirm these results which could have important applications in the clinical perspective

In combined high median and ulnar nerve injury, transfer of extensor digiti minimi (EDM) and extensor carpi ulnaris (ECU) nerve branches to restore intrinsic hand function is previously described. A segment of nerve graft is required in this operation. The aim of this study was to evaluate the feasibility of using the sensory branch of radial nerve (SRN) as an “in situ vascular nerve bridge'” (IVNB) instead of sural nerve graft. Twenty fresh cadavers were dissected. In proximal forearm incision, the feasibility of transferring the EDM/ECU branches to the distal stump of transected SRN was evaluated. In distal forearm incision, the two distal branches of the SRN were transected near the radial styloid process to determine whether transfer of the proximal stumps of these branches to the motor branches of the median (MMN) and ulnar (MUN) nerves is possible. The number of axons in each nerve was determined. The size of the dissected nerves and their location demonstrate that tension free nerve coaptation is easily possible in both proximal and distal incisions. Utilisation of the SRN as an IVNB instead of the conventional sural nerve graft has some advantages. Firstly, the sural nerve graft is a single branch and could be sutured to either the MMN or MUN, whereas the SRN has two terminal branches and can address both of them. Secondly, the IVNB has live Schwann cells and may accelerate the regeneration. Finally, this IVNB does not require leg incision and could be performed under regional anesthesia. The SRN as an IVNB is a viable option which can be used instead of conventional nerve graft in some brachial plexus or high median and ulnar nerve injuries when restoration of intrinsic hand function by transfer of EDM/ECU branches is attempted

The October 2015 Children’s orthopaedics Roundup³⁶⁰ looks at: Radiographic follow-up of DDH; When the supracondylar goes wrong; Apophyseal avulsion fractures; The ‘pulled elbow’; Surgical treatment of active or aggressive aneurysmal bone cysts in children; Improving stability in supracondylar fractures; Biological reconstruction may be preferable in children’s osteosarcoma; The paediatric hip fracture