Motor and sensory reinnervation in the hand after an end-to-side median to ulnar nerve coaptation in the forearm.

End-to-side coaptation of the median to ulnar nerve through an epineurial window was performed 5 cm proximal to the wrist in a patient with high median nerve injury associated with a 35 cm long nerve gap. Forty-three months after the operation, sensory examination revealed the presence of diminished protective sensation (3.61-4.31 NCM Semmes-Weinstein monofilament) in the large part of the median nerve dermatome. In the two-point discrimination test, single point was perceived in the median nerve dermatome pointing to the presence of protective sensation. MRI and EMG studies indicated limited motor reinnervation in the opponens pollicis muscle. This novel method of nerve repair may be chosen in the management of very long nerve gaps, where conventional methods are likely to give an unsuccessful result.     

Optimizing skeletal muscle reinnervation with nerve transfer

Denervation as a consequence of nerve injury causes profound structural and functional changes within skeletal muscle and can lead to a marked impairment in function of the affected limb. Prompt reinnervation of a muscle with a sufficient number of motion-specific motor axons generally results in good structural and functional recovery, whereas long-term denervation or insufficient or improper axonal recruitment uniformly results in poor functional recovery. Only nerve transfer has been highly efficacious in changing the clinical outcomes of patients with skeletal muscle denervation, especially in the case of proximal limb nerve injuries. Rapid reinnervation with an abundant number of motor axons remains the only clinically effective means to restore function to denervated skeletal muscles.     

Tendon transfer for median nerve palsy

A large number of tendon transfers have been described that restore opposition to the thumb and provide thumb and finger flexion. To provide optimal results following tendon transfers, one needs to follow the principles of tendon transfer: normal tissue equilibrium, movable joints, and a scar-free bed. Once these are present, we must look to available tables to determine an appropriate tendon transfer, matching up the lost muscle mass, fiber length, and cross-sectional area and then pick out muscle-tendon units of similar size, strength, and potential excursion. For low median nerve palsy (Table 4), we have found from our experimental and clinical studies that the FDS of the long and ring fingers or the wrist extensors (ECR or ECRL) best approximate the force and motion required for full thumb opposition and strength. These transfers are preferred in median nerve palsy or combined median ulnar nerve palsy when both strength and motion are required. In circumstances where only thumb mobility is desired, the EIP is an ideal transfer. Also, the extensor digitorum quinti (EDQ) and ADQ have sufficient mean fiber length (muscle excursion) to provide full thumb opposition. The palmaris longus transfer (Camitz transfer) is an abduction rather than an opposition transfer and should be reserved for selected cases of long-term carpal tunnel syndrome. For high median nerve palsy (Table 5), transfers of the brachioradialis or ECRL to restore lost thumb flexion (FPL) and side-to-side transfer of the FDP of the index finger are generally sufficient. A separate transfer to restore independent flexion of the index finger could be performed by utilizing the pronator teres or extensor carpi radialis ulnaris tendon muscle units. As they combine a proper direction of action, pulley location, and tendon insertion, tendon transfers for median nerve palsy are usually quite successful. In considering any of these elective procedures, however, it is important to remember that tendon transfers are muscle balance operations. The effect of transfer on restoring function must be carefully studied to assess the loss of function that such a transfer may endure.     

Tendon transfer for median nerve palsy

The article describes the approach practiced by the author from 1995. Mainly Hansen''s patients and lower forearm injuries formed the bulk of these. In Opponen''s transfer ECU was used only when others were not available as the wrist developed a tendency to radial deviation even when FCU was acting. PL with palmar aponeurosis as extension was used again in limited cases. The main stay was FDS and EIP. The Guyan''s canal and lower end of ulna were the common pulleys. APB and EPL two slip inserts yielded good results. The approach describes the procedure under three distinct headings of choosing motor, Pulley and insert. Varying combinations of these can be used as per requirement.KEY WORDS: Opponensplasty, opponens palsy, low median paralysis, tendon transfer for median nerve paralysis     

Thenar eminence quantitative sensory testing in the diagnosis of proximal median nerve compression.

Diagnosis of proximal median nerve compression (PMNC) remains a clinical challenge. The authors hypothesized that measurement of the sensibility of the thenar eminence might identify PMNC by demonstrating abnormal function in the palmar cutaneous branch of the median nerve. This hypothesis was evaluated by means of quantitative sensory testing of the thenar eminence in 33 healthy volunteers, 14 patients with carpal tunnel syndrome, and 35 patients with PMNC. The cutaneous pressure thresholds for one-point static touch (1PS) and two-point static touch (2PS) were measured with the Pressure-specified Sensory Device (Sensory Management Services, Baltimore, Maryland). There was no significant difference in thenar eminence sensibility between the healthy volunteers and the patients with carpal tunnel syndrome. In contrast, patients with PMNC had higher cutaneous pressure thresholds for 1PS (p<0.001), 2PS-pressure (p<0.001), and 2PS-distance (p<0.001) than did patients with carpal tunnel syndrome. The p values were less than 0.001 for each of these three comparisons between the healthy volunteers and the patients with PMNC. For the diagnosis of PMNC, quantitative sensory testing of the thenar eminence has a sensitivity of 90.3%, a specificity of 83.3%, and a positive predictive value of 87.5%.     

Cooling potentiates lidocaine inhibition of median nerve sensory fibers

To determine the effect of cooling on lidocaine potency, nine consenting volunteers underwent bilateral median nerve blocks using 1% lidocaine HCl solution. Room-temperature and ice-cold lidocaine were injected into either dominant or nondominant wrists. Subjects were blinded to the temperature of the anesthetic. Inhibition of A alpha sensory and motor fibers was assessed as the decline in sensory nerve action potentials and compound motor action potentials, respectively. Inhibition of C fibers was measured as an increase in skin temperature and a decline in galvanic skin potentials. All indices of nerve function demonstrated profound (P less than 0.001) time-related changes after injection of local anesthetic. When ice-cold lidocaine was injected, inhibition of sensory nerve action potentials was significantly greater at all time points (P = 0.001) than when room-temperature lidocaine was injected. Inhibition of C fibers as assessed by galvanic skin potentials was marginally faster (P = 0.07) when ice-cold lidocaine was used compared with room-temperature lidocaine. No differences between room-temperature and ice-cold lidocaine were observed in inhibition of compound motor action potentials, or in the increase in skin temperature. We conclude that inhibition of median sensory fibers may be increased by cooling 1% lidocaine HCl in an ice bath before injection.     

应用神经转位重建足底感觉功能

[目的]探讨神经转位方法重建足底感觉功能的效果。[方法]对足踝以下感觉均丧失者，选用隐神经为供体神经：于小腿中上1／3内后缘作纵行切口长约10cm，于皮下分离出隐神经后切断。于胫骨内后缘分开小腿三头肌显露胫神经，切断部分神经纤维后将隐神经近断端植入其中后行束外膜联合缝合。对于足背及外侧感觉存在而足底足趾感觉丧失者，选用腓肠神经作为供体神经：于外踝后缘向远端行纵切口长约5cm，游离出腓肠神经切断。内踝后方作长约5cm弧形切口，显露胫神经，切开神经外膜并切断部分神经纤维。于跟腱前方间隙打通隧道，将腓肠神经经隧道引至胫神经切开处植入，行束外膜联合缝合。[结果]本组9例患者均得到术后1．5～2年（平均21个月）的随访，顺向电生理检测法测定胫神经感觉传导速度为36．1～41．2（平均38．3）m／s：波幅（峰-峰波幅）在7～15．3μV（平均11．2μV）。9例患者均恢复了足底部痛、触觉。3例患者的两点辨别觉恢复正常。所有患者对行走过程满意，基本无定位错觉等不适情况。所有患者的足部肌肉未出现萎缩。神经供区感觉缺失在腓肠神经者只出现在外踝下方足的外侧区，在隐神经者出现在踝前方的小片区域，对下肢的功能无影响。[结论]应用神经转位的方法可有效的重建足底感觉功能。     

The sensory reinnervation of muscles following immediate and delayed nerve repair in the cat

An experiment has been performed on adult cats to investigate the sensory reinnervation of muscle spindles and tendon organs in peroneus brevis following immediate and delayed repair of the divided muscle nerve. The results demonstrate that delaying nerve repair for up to 6 weeks does not give rise to any significant detrimental effect on such reinnervation.     

Restoration of sensibility in irreparable ulnar and median nerve lesions with use of sensory nerve transfer: long-term follow-up of 20 cases

A prospective study was conducted to evaluate patient outcomes following sensory nerve transfer. Twenty patients with irreparable ulnar or median nerve lesions underwent the procedure. Nerve involvement was bilateral in 5 cases. The mean age of the patients at the time of surgery was 29 years. The mean paralysis time and the average length of follow-up were 59 and 78 months, respectively. Eighteen of 20 patients attended a sensory re-education program after surgery. Outcome was assessed objectively by functional sensory recovery testing and by the British Medical Research Council standards. Subjective outcome was assessed by a questionnaire. Two-point discrimination of less than 10 mm was achieved in 15 of 25 hands. The mean functional sensory recovery score was 83. Eighteen of 20 patients reported that the function of their hands improved after the procedure. Good or excellent results were associated with immediate transfer of the nerve, young age, and patients' attendance to the sensory re-education program after surgery. No differences were found between the recovery of ulnar and median nerves. Based on these results we suggest that sensory nerve transfer is a simple and reliable way of restoring sensibility to the hand with favorably comparable results over conventional nerve grafting in selected cases.     

Reconstruction of high ulnar nerve lesions by distal double median to ulnar nerve transfer

Ulnar nerve lesions around the elbow often carry an unfavorable prognosis due to insufficient sensory and intrinsic muscle recovery. We present a series of 7 cases in which restoration of ulnar innervated intrinsic muscles of the hand and of skin sensibility was achieved. This was accomplished by a distal connection of the anterior interosseous nerve and the superficial sensory palmar branch of the median nerve to the motor and sensory components of the ulnar nerve at Guyon's canal. The length of the follow-up period ranged from 1 to 3.5 years. Results were graded by the Highet-Zachary scale. Good motor and sensory recovery was obtained in 6 cases; only return of protective sensation occurred in the remaining case.     

Location of impaired sensory conduction of the median nerve in carpal tunnel syndrome

Sensory conduction of the median nerve at the carpal tunnel for eight consecutive 1 cm segments of the nerve was evaluated in 217 hands of 153 of our patients with carpal tunnel syndrome. Impairment was found to be highly focal and often confined to a single 1 cm segment of the nerve. The section of the nerve at or just distal to the distal margin of the carpal tunnel was affected most frequently, the section within the tunnel was affected less often, and the section proximal to the tunnel at the level of the mid-carpal and radio-carpal joints was affected least. The greatest contrast between frequencies of slowing at adjacent segments occurred at the proximal and distal margins of the carpal tunnel. The distribution of the nerve impairment was similar between the sexes; however, among the men the segment affected most frequently was located 1 cm distal to the segment affected most frequently among the women. The general pattern of slowing which we found does not substantiate some commonly-held opinions about the aetiology of carpal tunnel syndrome.