Florid Suprascapular Neuropathy after Primary Rotator Cuff Repair Attributed to Suprascapular Notch Constriction in the Setting of Double Crush Syndrome

This report describes a patient who had an open repair of a small supraspinatus tendon tear performed 6 months after an arthroscopic acromioplasty with debridement had failed to provide pain relief. Three months prior to the tendon repair, he had a two-level cervical spine discectomy and fusion (C4–5, C5–6) that improved his neck pain. Florid suprascapular neuropathy was detected 10 weeks after the open rotator cuff repair. Evidence of some nerve recovery resulted in a long period of observation. But unsatisfactory improvement warranted decompression of the suprascapular notch, which was found to be very stenotic. At surgery, there was no evidence of neuroma, cyst, or other compressing lesion or tissue. Therefore, it was ultimately hypothesized that there was an exacerbation of a preexisting, but clinically unrecognized, entrapment of the suprascapular nerve in the suprascapular notch in the setting of cervical radiculopathy (primarily C5). Retrospectively it was also concluded that had this compressive etiology been recognized, it would have favored prompt decompression rather than the long observation period. Three years was required to achieve a good result following suprascapular notch decompression. The underlying C5 radiculopathy may have created a “double crush syndrome” that contributed to the propensity for injury and the prolonged recovery. There should be heightened awareness of this problem in patients who do not have satisfactory improvement in shoulder pain from previous shoulder and neck surgery.     

Morphometry and Contents of the Suprascapular Notch with Potential Clinical Implications: Α Cadaveric Study

Background  The suprascapular notch (SN) represents the point along the route of the suprascapular nerve (SSN) with the greatest potential risk for injury and compression. Thus, factors reducing the area of the notch have been postulated for suprascapular neuropathy development. Methods  Thirty-one fresh-frozen shoulders were dissected. The contents of the SN were described according to four types as classified by Polguj et al and the middle-transverse diameter of the notch was measured. Also, the presence of an ossified superior transverse scapular ligament (STSL) was identified. Results  The ligament was partially ossified in 8 specimens (25.8%), fully ossified in 6 (19.35%), and not ossified in the remaining 17 (54.85%). The mean middle-transverse diameter of the SN was 9.06 mm (standard deviation [SD] = 3.45). The corresponding for type-I notches was 8.64 mm (SD = 3.34), 8.86 mm (SD = 3.12) was for type-II, and 14.5 mm (SD = 1.02) was for type III. Middle-transverse diameter was shorter when an ossified ligament was present (mean = 5.10 mm, SD = 0.88 mm), comparing with a partially ossified ligament (mean =7.67 mm, SD = 2.24 mm) and a nonossified one (mean = 11.12 mm, SD = 2.92 mm). No statistically significant evidence was found that the middle-transverse diameter depends on the number of the elements, passing below the STSL. Conclusion  Our results suggest that SSN compression could be more likely to occur when both suprascapular vessels pass through the notch. Compression of the nerve may also occur when an ossified transverse scapular ligament is present, resulting to significant reduction of the notch''s area.     

Long head of the triceps branch transfer to axillary nerve in C5, C6 brachial plexus injuries: anterior approach

Shoulder abduction is a very complex movement and quite important for upper limb function, as more distal functions depend on a stable shoulder, especially in C5, C6 brachial plexus injuries. Various studies in the literature have emphasized the importance of improved functional outcome and shoulder reanimation with concomitant neurotization of suprascapular nerve and axillary nerve in C5, C6 brachial plexus injuries. A number of approaches to axillary nerve transfer in brachial plexus injuries have been reported. The author describes an innovative anterior deltopectoral approach for axillary nerve transfers in five patients with C5, C6 brachial plexus injuries. The spinal accessory nerve was neurotized with the suprascapular nerve through a transverse supraclavicular incision. The axillary nerve and the long head of the triceps branch were identified through the anterior deltopectoral approach and neurotized at the posterior cord level. This approach gives easy access to other donors such as the medial pectoral, thoracodorsal, and median and ulnar nerves. Oberlin's transfer was also performed for elbow flexion by extending the deltopectoral incision. The regained shoulder active abduction (M5) averaged 120 degrees and active external rotation averaged 65 degrees at the final follow-up of 26 months (average). This anterior deltopectoral approach is an excellent alternative for axillary nerve transfer in brachial plexus injuries and produces results comparable with those of other approaches. All brachial plexus surgeons must understand the anatomy and the relationship of the axillary nerve to the surrounding structures. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.     

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.     

三通道电刺激仪的研制及对臂丛神经损伤的临床疗效

目的:研制可用于臂丛神经损伤治疗的三通道电刺激仪,并且将之应用于临床臂丛神经损伤患者,观察该仪器治疗臂丛神经损伤的临床效果。方法:由主控模块、显示模块、键盘模块、三个通道的电刺激发生器模块以及电源模块组成系统,可以连续交替释放脉冲刺激,针对不同神经和肌肉,选择不同的刺激位点。将60例臂丛神经损伤术后的患者随机分成试验组(30例)和对照组(30例),试验组术后第三周使用三通道电刺激仪治疗,对照组不做处理,患者术后随访6-12月后,观察患者上肢肩部、肘部功能恢复情况。结果:试验组治疗后上臂丛、全臂丛、下臂丛的肩部、肘部功能均好于治疗前,差异明显,均有统计学意义(P0.05);试验组上臂丛、全臂丛、下臂丛的肩部、肘部治疗效果均显著优于对照组,差异有统计学意义(P0.05)。结论:三通道电刺激仪可以有效地促进臂丛神经损伤后上肢功能的康复,可以对三组神经和肌肉交替进行电刺激,使用方便,并且便于携带,患者较为满意。     

Intact radial and median nerve after open third degree distal fracture of the humerus

A 54 year old man sustained a third degree open fracture at the distal part of the right humerus with massive soft tissue defect involving most of the upper arm. The radial and median nerves were completely bared and exposed by 6 cm for radial and 3 cm for median nerve. The nerves were in continuity, but there was complete rupture of surrounding muscles: biceps, triceps and brachialis. The fracture was stabilized by external fixation method--reinforced by wires. Preoperative and postoperative sensorimotor status of the right hand was good. One year later sensory and motoric status of right hand showed no deficiencies, but flexion and extension in elbow were limited to 100 and 180 degrees respectively. Pronosupination was restricted. This case report is consistent with results of biomechanical studies in vitro confirming high tolerance of radial and median nerve to stretching injury.     

Clinical and neuropathological study about the neurotization of the suprascapular nerve in obstetric brachial plexus lesions

Background

The lack of recovery of active external rotation of the shoulder is an important problem in children suffering from brachial plexus lesions involving the suprascapular nerve. The accessory nerve neurotization to the suprascapular nerve is a standard procedure, performed to improve shoulder motion in patients with brachial plexus palsy.

Methods

We operated on 65 patients with obstetric brachial plexus palsy (OBPP), aged 5-35 months (average: 19 months). We assessed the recovery of passive and active external rotation with the arm in abduction and in adduction. We also looked at the influence of the restoration of the muscular balance between the internal and the external rotators on the development of a gleno-humeral joint dysplasia. Intraoperatively, suprascapular nerve samples were taken from 13 patients and were analyzed histologically.

Results

Most patients (71.5%) showed good recovery of the active external rotation in abduction (60°-90°). Better results were obtained for the external rotation with the arm in abduction compared to adduction, and for patients having only undergone the neurotization procedure compared to patients having had complete plexus reconstruction. The neurotization operation has a positive influence on the glenohumeral joint: 7 patients with clinical signs of dysplasia before the reconstructive operation did not show any sign of dysplasia in the postoperative follow-up.

Conclusion

The neurotization procedure helps to recover the active external rotation in the shoulder joint and has a good prevention influence on the dysplasia in our sample. The nerve quality measured using histopathology also seems to have a positive impact on the clinical results.     

Investigations on the Incorporation of a Tritiated Ganglioside, GM1, in the Injured and Intact Sciatic Nerves of the Rat

Following injury of their left sciatic nerves by means of a standardized procedure, male rats received intravenous injections of a tritiated ganglioside. GM1, on different days during the process of regeneration. The rats were killed at two different times after the injection and the concentrations of the total radioactivity, nonvolatile radioactivity, and labelled GM1 were estimated in six segments of the crushed and intact sciatic nerves. The segments of the damaged nerves showed higher concentrations of radioactivity and a higher content of GM1 than the corresponding segments of the contralateral nerves. Within the immediate area of the lesion the highest levels were found on the 3rd and 6th days after the injury; the segments distal from the lesion showed the highest levels of activity on days 9 and 12. The nerve segments proximal to the site of the injury showed a low rate of radioactivity incorporation. The higher concentrations of [3H]GM1 in damaged nerves as well as the rate of incorporation as a function of time indicate that exogenous gangliosides may be involved in the processes of regeneration and have a bearing on the latter.     

The contribution of the supraspinatus muscle at sub-maximal contractions

During maximum effort, the supraspinatus muscle contributes approximately 50% of the torque need to elevate the arm, but this has not been examined at sub-maximal levels. The purpose of this study was to determine the contribution of the supraspinatus muscle to shoulder elevation at sub-maximal levels. Seven healthy subjects (four males, three females) performed isometric ramp contractions at the shoulder. Middle deltoid electromyography (EMG) and force applied at the wrist were collected before and after a suprascapular nerve block. For the same level of deltoid EMG, less external force will be measured after the nerve block as the supraspinatus muscle no longer contributes. The difference between the EMG/force curve was the contribution of the supraspinatus muscle. The supraspinatus contributed 40%, 95% CI [32%–48%], to shoulder elevation. The effect of angle (p = .67) and % maximal voluntary contraction (p = .13) on supraspinatus contribution were not significant. The maximum is slightly less than reported in a previous suprascapular nerve block study using maximal contractions. The results from this study can be used to assess supraspinatus contribution in rotator cuff tears, after rehabilitation interventions, and as a restraint in computation modelling.     

Changes in the concentration of enolase isozymes and S-100 protein in degenerating and regenerating rat sciatic nerve

Levels of enolase isozymes (alpha alpha, alpha gamma, and gamma gamma forms) and S-100 protein in rat sciatic nerves were determined during their degeneration and regeneration processes. The sciatic nerves were unilaterally crushed or severed. The rats were killed 1, 2, 6, and 8-9 weeks later, and both the proximal and distal portions of the damaged nerves were dissected. Control samples were obtained from the untreated contralateral hindlimbs. Enolase isozymes and S-100 protein in the nerve segments were determined with the enzyme immunoassay method. The control nerves contained about 40, 90, and 30 pmol/mg protein of alpha alpha, alpha gamma, and gamma gamma enolases, respectively, and 0.85 microgram/mg protein of S-100 protein. These levels were not affected by repetitive electrical stimulation of the nerve fibers in vivo. The levels of the nervous system-specific forms of enolase (alpha gamma and gamma gamma) and S-100 protein decreased markedly within a week in the distal portion of the crushed nerve (alpha gamma, 27 pmol/mg; gamma gamma, 5.5 pmol/mg; S-100 protein, 0.36 microgram/mg) with apparently no change in the concentration of alpha alpha enolase. These levels in the proximal portion of the crushed nerve remained unaltered. The sensory and motor functions impaired by the sciatic nerve crush showed a recovery more or less after 4-9 weeks. This recovery was accompanied by a gradual regaining of the specific proteins in the distal portion of injured nerves (alpha gamma, 64 pmol/mg; gamma gamma, 13 pmol/mg; S-100 protein, 0.63 microgram/mg at the 8-9th week).     

Fate of stem cell transplants in peripheral nerves

While damaged peripheral nerves demonstrate some potential to regenerate, complete functional recovery remains infrequent, owing to a functional loss of supportive Schwann cells distal to the injury. An emerging solution to improve upon this intrinsic regenerative capacity is to supplement injured nerves with stem cells derived from various tissues. While many of these strategies have proven successful in animal models, few studies have examined the behavior of transplanted stem cells in vivo, including whether they survive and differentiate. In previous work, we demonstrated that cells derived from neonatal rodent dermis (skin-derived precursor cells, or SKPs) could improve regenerative parameters when transplanted distal to both acute and chronic nerve injuries in Lewis rats. The aim of this work was to track the fate of these cells in various nerve injury paradigms and determine the response of these cells to a known glial growth factor. Here, we report that SKPs survive, respond to local cues, differentiate into myelinating Schwann cells, and avoid complete clearance by the host's immune defenses for a minimum of 10 weeks. Moreover, the ultimate fate of SKPs in vivo depends on the nerve environment into which they are injected and can be modified by inclusion of heregulin-1β.     

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.     

Management of iatrogenic injury to the spinal accessory nerve

Spinal accessory nerve injury results in a debilitating shoulder dysfunction. The trapezius is a major suspensory muscle of the shoulder girdle, and paralysis results in chronic pain and debility from disruption of synchronous scapulohumeral rhythm. This injury usually follows a simple posterior triangle lymph node biopsy and is treatable if appropriate measures are taken in a timely fashion. A major pitfall in early management is either failure to recognize or acknowledge the injury or hoping that it will resolve with conservative treatment. Variation of innervation of the trapezius alters clinical presentation and can make diagnosis difficult. We present a series of six patients with iatrogenic spinal accessory nerve injury following a neck node biopsy. Pain was the most common presenting symptom, and a loss of sustained abduction was the most common physical sign. Three patients had a primary nerve repair and the other three patients had nerve grafting. Maximum recovery time ranged from 4 to 10 months. All patients had varying degrees of recovery of motor function, and all six patients were 100 percent painfree. An algorithm for the management of this distressing condition emphasizes the importance of early referral and highlights the pitfalls in making an accurate diagnosis. Whereas conservative therapy is less predictable and needs careful selection, it also runs the risk of delaying a more effective surgical management. Early operative intervention is more definitive and has the best functional results. Prevention is key and is best achieved by avoiding unnecessary biopsies of the posterior triangle lymph node. When operating, knowledge of posterior neck anatomy and judicious use of the bipolar cautery and magnifying loupes are essential in preventing this problem.     

Traumatic Pseudoaneurysm of Axillary Artery Combined with Brachial Plexus Injury

Traumatic pseudoaneurysm of the axillary artery combined with brachial plexus injury is extremely rare. The factors that influence the symptoms and functional recovery related to this condition are unclear. Nine patients who had sustained this trauma were surgically treated at our unit between June 1999 and November 2010. The cause of trauma, symptoms, signs and examinations of neurological and vascular deficits, and the surgical findings of the involved nerves and vessels were recorded in detail. The functional recovery of vessels and nerves, as well as the extent of pain, were evaluated, respectively. The average length of patient follow-up was 4.5 years (range, 24 months to 11.3 years). After vessel repair, whether by endovascular or operative treatment, the distending, constant, and pulsating pain was relieved in all patients. Furthermore, examination of the radial artery pulse on the repaired side appeared normal at last follow-up. All patients showed satisfactory sensory recovery, with motor recovery rated as good in five patients and fair in four patients. The symptom characteristics varied with the location of the damage to the axillary artery. Ultrasound examination and computed tomography angiography are useful to evaluate vascular injury and provide valuable information for operative planning. Surgical exploration is an effective therapy with results related to the nerve injury condition of the brachial plexus.     

Electrophysiological experiments on the mechanism and accuracy of neuromuscular specificity in the axolotl.

The supracoracoideus muscle of the axolotl shoulder girdle is innervated by two nerves, the supracoracoideus nerve (SC) supplying most of the muscle and the posterior supracoracoideus (PSC) supplying the posterior corner. All the muscle fibres are multiply innervated and at the border between the two innervations many muscle fibres, when penetrated by a microelectrode, show junction potentials from both nerves. In such cases one junction potential is often very small, below the threshold for exciting muscle contraction, the other large and effective at exciting the muscle. If the SC nerve is cut, the territory of the PSC nerve expands over several weeks. Upon regrowth of the cut nerve it reinnervates its old muscle fibres and removes the previous foreign innervation, the borderline between the two nerve territories being established exactly as before. This depends upon two processes, sprouting of nerves and a competitive repression of transmission from nerves ending on foreign muscle fibres.     

大白鼠交感节前神经再生的研究Ⅰ.生化、组化与功能观察

用液氮骤冻造成大白鼠交感节前神经变性后,通过神经末梢乙酰胆碱含量、胆碱酯酶活性测定以及电刺激交感干时外周反应等研究其再生规律。结果表明冻伤后3周内再生过程进展迅速,神经结构与功能均有相当程度的恢复;3周后再生过程转慢,直至一年时各指标仍远未达到正常。这证明交感节前神经的再生过程不同于中枢及其它外周神经而独具特征。     

Loss and recovery of the blood–nerve barrier in the rat sciatic nerve after crush injury are associated with expression of intercellular junctional proteins

The blood–nerve barrier in peripheral nerves is important for maintaining the environment for axons. Breakdown of the barrier by nerve injury causes various pathologies. We hypothesized that the breakdown and recovery of the blood–nerve barrier after injury are associated with the changes in the expression of intercellular junctional proteins. To test this hypothesis, we induced crush injuries in the rat sciatic nerve by ligation and analyzed spatiotemporal changes of claudin-1, claudin-5, occludin, VE-cadherin, and connexin43 by immunoconfocal microscopy and morphometry and compared them with changes in the permeability of the blood–nerve barrier by intravenous and local administration of Evans blue–albumin (EBA). On day 1 after removal of the ligature EBA leaked into the connective tissue in the endoneurium and then the leakage gradually decreased and disappeared on day 7. On day 1 claudin-1, claudin-5, occludin, VE-cadherin, and connexin43 had totally disappeared from the perineurium and endoneurium. Thereafter, claudin-1, claudin-5, occludin, and VE-cadherin recovered from day 2, whereas connexin43 was redetected on day 5. These results indicate that the breakdown and following recovery of the blood–nerve barrier are closely associated with changes in the expression of claudins, occludin, VE-cadherin, and connexin43 and that the recovery time course is similar but nonidentical.     

Postinjury Changes in Platelet-Derived Growth Factor-Like Activity in Fish and Rat Optic Nerves

The poor regenerative ability of the CNS of mammals has been attributed, at least in part, to the presence of mature oligodendrocytes, which have been shown to inhibit axonal growth. Proliferation of oligodendrocyte progenitor cells in the rat optic nerve during development, and thereby the timing of oligodendrocyte differentiation, has been shown to depend on a factor derived from type 1 astrocytes, later characterized as platelet-derived growth factor (PDGF). In the present study we examine whether injury to the optic nerve induces changes in the levels of PDGF in spontaneously regenerating systems, compared with nonregenerating systems. Soluble substances, derived from nonneuronal cells surrounding injured fish and rat optic nerves, were prepared and examined for the presence of PDGF immunoreactivity and biological mitogenic activity on PDGF-responsive cells. The results suggest that PDGF-like mitogenic activity and immunoreactivity are present in both fish and rat optic nerves. However, in the rat optic nerve PDGF levels increased after axonal injury, whereas in the fish optic nerve injury was accompanied by an apparent decrease in PDGF-like levels. The results are discussed with respect to the possible role of PDGF in regeneration.