Outcome following Nerve Repair of High Isolated Clean Sharp Injuries of the Ulnar Nerve

Objective

The detailed outcome of surgical repair of high isolated clean sharp (HICS) ulnar nerve lesions has become relevant in view of the recent development of distal nerve transfer. Our goal was to determine the outcome of HICS ulnar nerve repair in order to create a basis for the optimal management of these lesions.

Methods

High ulnar nerve lesions are defined as localized in the area ranging from the proximal forearm to the axilla just distal to the branching of the medial cord of the brachial plexus. A meta-analysis of the literature concerning high ulnar nerve injuries was performed. Additionally, a retrospective study of the outcome of nerve repair of HICS ulnar nerve injuries at our institution was performed. The Rotterdam Intrinsic Hand Myometer and the Rosén-Lundborg protocol were used.

Results

The literature review identified 46 papers. Many articles presented outcomes of mixed lesion groups consisting of combined ulnar and median nerves, or the outcome of high and low level injuries was pooled. In addition, outcome was expressed using different scoring systems. 40 patients with HICS ulnar nerve lesions were found with sufficient data for further analysis. In our institution, 15 patients had nerve repair with a median interval between trauma and reconstruction of 17 days (range 0–516). The mean score of the motor and sensory domain of the Rosen''s Scale instrument was 58% and 38% of the unaffected arm, respectively. Two-point discrimination never reached less then 12 mm.

Conclusion

From the literature, it was not possible to draw a definitive conclusion on outcome of surgical repair of HICS ulnar nerve lesions. Detailed neurological function assessment of our own patients showed that some ulnar nerve function returned. Intrinsic muscle strength recovery was generally poor. Based on this study, one might cautiously argue that repair strategies of HICS ulnar nerve lesions need to be improved.     

The position of crossing branches of the medial antebrachial cutaneous nerve during cubital tunnel surgery in humans

The posterior branch of the medial antebrachial cutaneous nerve courses in proximity to the cubital tunnel and is particularly prone to injury during ulnar nerve release at the elbow. Inadvertent injury to medial antebrachial cutaneous nerve branches during surgery can result in the formation of painful neuromas that can be misdiagnosed as recurrent disease. It is important to understand the relevant anatomy of the medial antebrachial cutaneous nerve branches during cubital tunnel surgery to avoid significant postoperative morbidity. This prospective observational anatomic study examined the position of the posterior branch of the medial antebrachial cutaneous nerve in relationship to a standard approach to the cubital tunnel in a randomly selected group of 97 patients undergoing primary surgery over a 3-year period. Medial antebrachial cutaneous nerve branches were noted to cross at or proximal to the medial humeral epicondyle 61 percent of the time at an average proximal distance of 1.8 cm. Medial antebrachial cutaneous nerve branches were noted to cross distal to the medial humeral epicondyle 100 percent of the time at an average distal distance of 3.1 cm. Understanding the general position of crossing medial antebrachial cutaneous nerve branches during ulnar nerve release at the elbow may help to prevent iatrogenic injury to this cutaneous nerve.     

The impact of extended electrodiagnostic studies in Ulnar Neuropathy at the elbow

Background  

This study aimed to explore the value of extended motor nerve conduction studies in patients with ulnar nerve entrapment at the elbow (UNE) in order to find the most sensitive and least time-consuming method. We wanted to evaluate the utility of examining both the sensory branch from the fifth finger and the dorsal branch of the ulnar nerve. Further we intended to study the clinical symptoms and findings, and a possible correlation between the neurophysiological findings and pain.     

Brachial plexus injury.

A 28-year-old man shot himself in the left posterior triangle of the neck with a shotgun. At the initial operation secondary repair of the resultant brachial plexus injury was decided upon in view of the difficulty in assessing lesions in continuity at this point after injury. The patient had total brachial plexus palsy. Nine weeks after the injury sensory and motor function were returning and the only element of the brachial plexus not showing evidence of nerve fibre continuity was the musculocutaneous nerve. Sural nerve autografts were sutured between the trimmed proximal and distal stumps of this nerve. By 4 months after the injury there was further improvement in both sensory and motor function, and by 18 months there was sensation in the autonomous zones of both median and ulnar nerves and good return of muscle power.     

Functional and morphometric evaluation of end-to-side neurorrhaphy for muscle reinnervation

This study was undertaken to quantify the effect of motor collateral sprouting in an end-to-side repair model allowing end organ contact. Besides documentation of the functional outcome of muscle reinnervation by end-to-side neurorrhaphy, this experimental work was performed to determine possible downgrading effects to the donor nerve at end organ level. In 24 female New Zealand White rabbits, the motor nerve branch to the rectus femoris muscle of the right hindlimb was dissected, cut, and sutured end-to-side to the motor branch to the vastus medialis muscle after creating an epineural window. The 24 rabbits were divided into two groups of 12 each, with the second group receiving additional crush injury of the vastus branch. After a period of 8 months, maximum tetanic tension in the reinnervated rectus femoris and the vastus medialis muscles was determined. The contralateral healthy side served as control. The reinnervated rectus femoris muscle showed an average maximum tetanic force of 24.9 N (control 26.2 N, p = 0.7827), and the donor- vastus medialis muscle 11.0 N (control 7.3 N, p = 0.0223). There were no statistically significant differences between the two experimental groups (p = 0.9914). The average number of regenerated myelinated nerve fibers in the rectus femoris motor branch was 1,185 +/- 342 (control, 806 +/- 166), and the mean diameter was 4.6 +/- 0.6 microm (control, 9.4 +/- 1.0 microm). In the motor branch to the vastus medialis muscle, the mean fiber number proximal to the coaptation site was 1227 (+/-441), and decreased distal to the coaptation site to 795 (+/-270). The average difference of axon counts in the donor nerve proximal to distal regarding the repair site was 483.7 +/- 264.2. In the contralateral motor branch to the vastus medialis muscle, 540 (+/- 175) myelinated nerve fibers were counted. In nearly all cross-section specimens of the motor branch to the vastus medialis muscle, altered nerve fibers could be identified in one fascicle distal and proximal to the repair site. The results show a relevant functional reinnervation by end-to-side neurorrhaphy without functional impairment of the donor muscle. It seems to be evident that most axons in the attached segment were derived from collateral sprouts. Nonetheless, the present study confirms that end-to-side neurorrhaphy is a reliable method of reconstruction for damaged nerves, which should be applied clinically in a more extended manner.     

T2-Signal of Ulnar Nerve Branches at the Wrist in Guyon’s Canal Syndrome

Objective

To evaluate T2-signal of high-resolution MRI in distal ulnar nerve branches at the wrist as diagnostic sign of guyon’s-canal-syndrome (GCS).

Materials and Methods

11 GCS patients confirmed by clinical/electrophysiological findings, and 20 wrists from 11 asymptomatic volunteers were prospectively included to undergo the following protocol: axial T2-weighted-fat-suppressed and T1-weighted-turbo-spin-echo-sequences (3T-MR-scanner, Magnetom/Verio/Siemens). Patients were examined in prone position with the arm extended and wrist placed in an 8-channel surface-array-coil. Nerve T2-signal was evaluated as contrast-to-noise-ratios (CNR) from proximal-to-distal in ulnar nerve trunk, its superficial/sensory and deep/motor branch. Distal motor-nerve-conduction (distal-motor-latency (dml)) to first dorsal-interosseus (IOD I) and abductor digiti minimi muscles was correlated with T2-signal. Approval by the institutional review-board and written informed consent was given by all participants.

Results

In GCS, mean nerve T2-signal was strongly increased within the deep/motor branch (11.7±4.8 vs.controls:−5.3±2.4;p = 0.001) but clearly less and not significantly increased in ulnar nerve trunk (6.8±6.4vs.−7.4±2.5;p = 0.07) and superficial/sensory branch (−2.1±4.9vs.−9.7±2.9;p = 0.08). Median nerve T2-signal did not differ between patients and controls (−9.8±2.5vs.−6.7±4.2;p = 0.45). T2-signal of deep/motor branch correlated strongly with motor-conduction-velocity to IOD I in non-linear fashion (R² = −0.8;p<0.001). ROC-analysis revealed increased nerve T2-signal of the deep/motor branch to be a sign of excellent diagnostic performance (area-under-the-curve 0.94, 95% CI: 0.85–1.00; specificity 90%, sensitivity 89.5%).

Conclusions

Nerve T2-signal increase of distal ulnar nerve branches and in particular of the deep/motor branch is highly accurate for the diagnostic determination of GCS. Furthermore, for the first time it was found in nerve entrapment injury that T2-signal strongly correlates with electrical-conduction-velocity.     

Distal, dorsal superior extremity plasty

Multiple deep wrinkles and redundant skin over the dorsal hand, wrist, and forearm develop and become of cosmetic importance to some patients as they age. Distal, dorsal superior extremity plasty was performed in selected patients by excising redundant skin and wrinkles from the dorsal hands, wrists, and forearms. The area of skin to be excised is elliptical, with the long axis of the ellipse centered over the wrinkles on the dorsal wrist. The amount of skin to be excised (i.e., the short axis of the ellipse) is determined by grasping the dorsal wrist skin, hence advancing the dorsal forearm and hand skin, while the patient flexes the wrist. This maneuver is performed to avoid excessive excision of dorsal wrist skin, which would cause decreased wrist flexion. The surgical procedure is performed with use of magnification to avoid sensory nerve injury. A relatively large volume of lidocaine is injected subcutaneously to increase the distance between the skin and nerves and therefore decrease the risk of nerve injury. The skin edges are undermined for 1 to 1(1/2) cm, and the wound is closed in two layers. The wrist is splinted in 30 to 45 degrees of extension to decrease wound tension. The procedure produces long-lasting, good to excellent cosmetic improvement and patient satisfaction. The dorsal wrist, hand, and forearm appear smoother and more youthful, and scars are relatively inconspicuous. Potential significant complications include injury to the superficial branch of the radial nerve and dorsal branch of the ulnar nerve, wound dehiscence, and decreased range of motion of the wrist. Use of magnification, a bloodless field, injection of a relatively large volume of local anesthetic (10 to 12 cc), knowledge of regional anatomy, and careful surgical technique decrease the risk of nerve injury. Avoidance of injury to the superficial sensory branches of the radial and ulnar nerves is absolutely necessary for patient satisfaction. Avoidance of injury to the wound edges with good surgical technique, postoperative immobilization with the wrist in an extended position, and subsequent advancement of the wrist to a neutral position for several weeks decrease the risk of wound dehiscence. Avoidance of excessive skin excision and prolonged wrist immobilization lowers the risk of decreasing range of motion. There have been no complications in patients who underwent this procedure.     

Significance of shoulder function in the reconstruction of prehension with double free-muscle transfer after complete paralysis of the brachial plexus

Reconstruction of shoulder stability and movement in cases with complete paralysis of the brachial plexus was performed to improve the outcomes for universal function of prehension after double free-muscle transfer (Doi's procedure). In cases in which the C5 or C6 nerve root was available as a donor, neurotization of the supra-scapular nerve was performed with a nerve graft. If the C5 or C6 nerve root was not available, then the contralateral C7 nerve root was chosen as the donor motor nerve and was transferred to the suprascapular nerve by using a vascularized ulnar nerve graft. Seven cases with ipsilateral C4, C5, or C6 nerve root transfer to the suprascapular nerve and one with contralateral C7 transfer were evaluated, and the functional outcomes for the range of shoulder motion were compared with those for patients who had undergone arthrodesis of the humeroscapular joint or had undergone no procedures for shoulder function reconstruction. The patients who underwent supra-scapular nerve repair demonstrated statistically significantly better ranges of motion for flexion and abduction of the shoulder, compared with the other two groups. Shoulder function is important for achieving prehensile function among patients with complete paralysis of brachial function, when they undergo double free-muscle transfer.     

Retrograde tracing and toe spreading after experimental autologous nerve transplantation and crush injury of the sciatic nerve: a descriptive methodological study

ABSTRACT: Evaluation of functional and structural recovery after peripheral nerve injury is crucial to determine the therapeutic effect of a nerve repair strategy. In the present study, we examined the relationship between the structural evaluation of regeneration by means of retrograde tracing and the functional evaluation analysis of toe spreading. Two standardized rat sciatic nerve injury models were used to address this relationship. As such, animals received either a 2 cm sciatic nerve defect (neurotmesis) followed by autologous nerve transplantation (ANT animals) or a crush injury with spontaneous recovery (axonotmesis; CI animals). Functional recovery of toe spreading was observed over an observation period of 84 days. In contrast to CI animals, ANT animals did not reach pre-surgical levels of toe spreading. After the observation period, the lipophilic dye DiI was applied to label sensory and motor neurons in dorsal root ganglia (DRG; sensory neurons) and spinal cord (motor neurons), respectively. No statistical difference in motor or sensory neuron counts could be detected between ANT and CI animals. In the present study we could indicate that there was no direct relationship between functional recovery (toe spreading) measured by SSI and the number of labelled (motor and sensory) neurons evaluated by retrograde tracing. The present findings demonstrate that a multimodal approach with a variety of independent evaluation tools is essential to understand and estimate the therapeutic benefit of a nerve repair strategy.     

Functional Recovery Occurs Even After Partial Remyelination of Axon-Meshed Median and Ulnar Nerves in Mice

Upper limb nerve injuries are common, and their treatment poses a challenge for physicians and surgeons. Experimental models help in minimum exploration of the functional characteristics of peripheral nerve injuries of forelimbs. This study was conducted to characterize the functional recovery (1, 3, 7, 10, 14, and 21 days) after median and ulnar nerve crush in mice and analyze the histological and biochemical markers of nerve regeneration (after 21 days). Sensory–functional impairments appeared after 1 day. The peripheral nerve morphology, the nerve structure, and the density of myelin proteins [myelin protein zero (P0) and peripheral myelin protein 22 (PMP22)] were analyzed after 21 days. Cold allodynia and fine motor coordination recovery occurred on the 10th day, and grip strength recovery was observed on the 14th day after injury. After 21 days, there was partial myelin sheath recovery. PMP22 recovery was complete, whereas P0 recovery was not. Results suggest that there is complete functional recovery even with partial remyelination of median and ulnar nerves in mice.

     

Electrophysiological and histopathological changes in peripheral nerves of postnatally undernourished and rehabilitated young rhesus monkeys

Nerve condition velocity of ulnar and tibial nerves and qualitative histology of ulnar nerve were studied in young rhesus monkeys. Motor nerve condition velocity of both the nerves and amplitude of sensory response of ulnar nerve were significantly decreased in even moderate protein calorie malnourished (PCM) group of monkeys. Increased paranodal gap, segmental demyelination, thin myelinated fibres and prominent Schmidt Lanterman Clefts were also observed in PCM group. There was complete recovery in motor nerve conduction velocity in the nerves of both limbs while partial in amplitude of sensory response in proximal segment of ulnar nerve on nutritional rehabilitation of 10-12 weeks.     

The 'loge de Guyon'. A contribution to the clinical anatomy of the human hand

In 40 hands of adults the 'loge de Guyon', a narrow bounded area within the proximal hypothenar region, has been dissected to realize an exact determination of the important characteristics of size. Beside measurements of the wall structures in the region of the pisiform bone, the hook of hamate and the entrances of the loge, variations of muscles and the position of the ulnar artery and nerve with their terminal branches have also been examined. The deep palmar branch of the ulnar artery crosses the rami of the ulnar nerve on the palmar side in 65% of cases. The branch of the artery crosses on the dorsal side in 30% and in 5% the ramus profundus of the ulnar artery runs between both terminal branches of the ulnar nerve. The clinical significance of the loge is emphasized, whereas the irregular nomenclature in the national and international literature is discussed in detail.     

The effect of two episodes of denervation and reinnervation on skeletal muscle contractile function.

Sensory or motor "baby-sitting" has been proposed as a clinical strategy to preserve muscle integrity if motion-specific axons must regenerate over a long distance to reach denervated target muscles. Denervated muscles are innervated temporarily by using axons from nearby sensory or motor nerves. After motion specific motor axons have reached the target, the baby-sitter nerve is severed and motion-specific axons are directed to the target. Although this strategy minimizes denervation time, the requisite second episode of denervation and reinnervation might be deleterious to muscle contractile function. This study was designed to test the hypothesis that two sequential episodes of skeletal muscle denervation and reinnervation result in greater force and power deficits than a single peripheral nerve injury and repair. Adult Lewis rats underwent either transection and epineurial repair or sham exposure of the left peroneal nerve. After a 4-month recovery period, the contractile properties of the extensor digitorum longus muscle of the sham exposure group (control, n = 9) and one of the nerve division and repair groups (repair group 1, n = 9) were evaluated with measurements of the maximum tetanic isometric force, peak power, and maximal sustained power. A third group of rats underwent a second cycle of nerve division and repair (repair group 2, n = 9) at this same time point. Four months postoperatively, contractile properties of the extensor digitorum longus muscles were evaluated. Maximum tetanic isometric force and peak power were significantly reduced in repair group 2 rats as compared with repair group 1 and control rats. Maximal sustained power was not significantly different between the groups. These data support our working hypothesis that skeletal muscle contractile function is adversely affected by two cycles of denervation and reinnervation as compared with a single episode of nerve division and repair.     

Outcomes after Anterior Interosseous Nerve to Ulnar Motor Nerve Transfer

Background  Ulnar nerve lesions proximal to the elbow can result in loss of intrinsic muscle function of the hand. The anterior interosseous nerve (AIN) to deep motor branch of the ulnar nerve (DBUN) transfer has been demonstrated to provide intrinsic muscle reinnervation, thereby preventing clawing and improving pinch and grip strength. The purpose of this study was to evaluate the efficacy of the AIN to DBUN transfer in restoring intrinsic muscle function for patients with traumatic ulnar nerve lesions. Methods  We performed a prospective, multi-institutional study of outcomes following AIN to DBUN transfer for high ulnar nerve injuries. Twelve patients were identified, nine of which were enrolled in the study. The mean time from injury to surgery was 15 weeks. Results  At final follow-up (mean postoperative follow-up 18 months + 15.5), clawing was observed in all nine patients with metacarpophalangeal joint hyperextension of the ring finger averaging 8.9 degrees (+ 10.8) and small finger averaging 14.6 degrees (+ 12.5). Grip strength of the affected hand was 27% of the unaffected extremity. Pinch strength of the affected hand was 29% of the unaffected extremity. None of our patients experienced claw prevention after either end-to-end ( n  = 4) or end-to-side ( n  = 5) AIN to DBUN transfer. Conclusion  We conclude that, in traumatic high ulnar nerve injuries, the AIN to DBUN transfer does not provide adequate intrinsic muscle reinnervation to prevent clawing and normalize grip and pinch strength.     

Forearm compartment syndrome: anatomical analysis of surgical approaches to the deep space

Forearm compartment syndrome is a surgical emergency that usually requires release of the superficial muscle compartments. In some clinical situations it is imperative to also explore the deep muscle compartments. There are no anatomical guides for surgical exploration of the deep compartments that would minimize collateral damage to surrounding vessels, nerves, and muscles. Surgical injury in the setting of ischemia, especially vascular injury, compounds the tissue damage that has already occurred. The authors evaluated four surgical approaches (three volar and one dorsal) to the deep forearm by performing detailed anatomical dissections on 10 embalmed and plastinated cadavers. They used a scoring system to rate the approaches for their ability to visualize the deep space without causing iatrogenic injury to superficial muscles, arteries, and nerves. In the volar forearm, an ulnar approach to the deep space is simple, causes the least iatrogenic surgical injury, and provides access to the deep volar forearm structures. The plane of dissection is between the flexor carpi ulnaris and the flexor digitorum superficialis. Dividing one or two distal segmental branches of the ulnar artery to the distal flexor digitorum superficialis exposes the pronator quadratus. Lifting the ulnar neurovascular bundle with the flexor digitorum superficialis in the middle third of the forearm exposes the flexor digitorum profundus and the flexor pollicis longus. This approach to the deep space requires no sharp dissection. In the dorsal forearm, a midline approach between the extensor digitorum communis and the extensor carpi radialis brevis is simple and safe.     

Ramification pattern of intermetacarpal branches of the deep branch (ramus profundus) of the ulnar nerve in the human hand.

The branching pattern of the deep branch (ramus profundus) of the ulnar nerve and its relation with the target were analyzed in the human hand by an improved dissection method. After sending off branches to the hypothenar muscles, the r. profundus branched off an ulnar stem and a radial stem to the fourth, to the third and to the second intermetacarpal spaces, respectively, in this order, and an ulnar stem to the first to become terminal branches. The ulnar stems included an ulnar interosseous branch and a superficial articular branch in addition to a lumbrical branch in the third and fourth intermetacarpal spaces. The radial stems included only a radial interosseous branch. The branching pattern of the ulnar stems as well as its topographical relationship with the radial stems indicated a fundamental spatial arrangement of the branches in the intermetacarpal spaces: the lumbrical, superficial articular, ulnar interosseous and radial interosseous branches were arranged fundamentally in this order from ulnar to radial in each space; the first three branches may form a common trunk. The present observations demonstrate that individual nerves in the extremities may have a regular branching pattern, contrary to most of the previous observations.     

Incidence of early posterior shoulder dislocation in brachial plexus birth palsy

Background

Nerve transfers are commonly employed in the treatment of brachial plexus injuries. We report the use of a new donor for transfer, the platysma motor branch.

Methods

A patient with complete avulsion of the brachial plexus and phrenic nerve paralysis had the suprascapular nerve neurotized by the accessory nerve, half of the hypoglossal nerve transferred to the musculocutaneous nerve, and the platysma motor branch connected to the medial pectoral nerve.

Results

The diameter of both the platysma motor branch and the medial pectoral nerve was around 2 mm. Eight years after surgery, the patient recovered 45° of abduction. Elbow flexion and shoulder adduction were rated as M4, according to the BMC. There was no deficit after the use of the above-mentioned nerves for transfer. Volitional control was acquired for independent function of elbow flexion and shoulder adduction.

Conclusion

The use of the platysma motor branch seems promising. This nerve is expendable; its section led to no deficits, and the relearning of motor control was not complicated. Further anatomical and clinical studies would help to clarify and confirm the usefulness of the platysma motor branch as a donor for nerve transfer.     

A multivariate approach to the treatment of peripheral nerve transection injury: the role of electromagnetic field therapy

A multivariate approach to the treatment of peripheral nerve transection injury has been used in a rat model. A pilot study (48 animals, 8 groups) examined variables associated with the method and timing of surgical repair, the arrest of wallerian degeneration, and the role of pulsing electromagnetic field therapy (PEMF) in functional recovery. A second phase (90 animals, 6 groups) then studied the timing and duration of pulsing electromagnetic field therapy as the only variable in larger groups of animals. The pilot study revealed that a vein-graft conduit did not improve functional recovery compared with standard epineurial repair. Additionally, delayed repair compared favorably with immediate repair. The use of chlorpromazine to inhibit the toxic effects of calcium influx appeared to enhance early functional recovery, and the combination of delayed nerve repair and pulsing electromagnetic field therapy seemed to consistently improve function. The second phase of the study has demonstrated (for the first time) statistical improvement in ambulation in animals treated with delayed surgical repair and prolonged pulsing electromagnetic field therapy. We postulate that future treatment of nerve transection injuries will involve a combined treatment regimen consisting of the immediate arrest of wallerian degeneration, delayed surgery, and pulsing electromagnetic field therapy.     

Thenar and hypothenar muscles and their innervation by the ulnar and median nerves in the human hand.

The thenar and hypothenar muscles as well as their supplying nerves were analyzed with an improved dissecting method. Among the four thenar muscles, the m. abductor pollicis brevis (AbPB) has a separate muscle belly, whereas the m. opponens pollicis (OP), the superficial and deep heads of the flexor pollicis brevis (sFPB and dFPB), and the adductor pollicis (AdP) are fused with each other to make a single mass (deep thenar muscle group). These muscles are innervated by branches of the recurrent nerve and the accessory recurrent nerve from the median nerve as well as by terminal branches of the deep branch (ramus profundus) of the ulnar nerve. These three nerves frequently form a loop within the deep thenar muscle group (thenar loop), and a branch to the OP and one to deep parts of the sFPB often make a smaller loop (intrathenar loop), whereas the AbPB receives a separate nerve branch. Among the hypothenar muscle, the m. abductor digiti minimi and the m. flexor digiti minimi brevis are fused with each other, and their supplying nerves frequently form a loop in these muscles (intrahypothenar loop), whereas the m. opponens digiti minimi is separated from the others and receives a separate nerve branch. In the distribution pattern of supplying nerves to the thenar and hypothenar muscles, we find regularities in that they branch off in a regular manner from the ulnar and the median nerve, and that nerve branches to those muscles with fused bellies frequently communicate with each other to make loops.