Cervical radiculopathy and coexisting distal entrapment neuropathies: double-crush syndromes?

The Incidence of Double Crush Syndrome in Surgically Treated Patients

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVES

Cervical radiculopathy and peripheral entrapment neuropathies often have overlapping symptoms that are difficult to distinguish on physical examination. Small-scale studies have attempted to report the incidence of this phenomenon, often called double crush syndrome (DCS), with varying results. The present study aims to determine the incidence of concomitant cervical radiculopathy and peripheral nerve compression and to determine if the DCS hypothesis, which states that compression of a nerve at one site leaves it more susceptible to compression at another, is valid.

METHODS

The PearlDiver database was queried from 2010 to 2020. The incidence of peripheral neuropathy in cervical radiculopathy was assessed. Propensity score matching was used to determine if patients with cervical radiculopathy were more likely to have peripheral nerve compression compared to controls, and vice versa, to test the DCS hypothesis.

RESULTS

The database contains records of 90,772 632 patients. The incidence of carpal tunnel syndrome (CTS) or peripheral ulnar nerve compression (PUnC) in cervical radiculopathy was 9.98% and 3.15%, respectively. The incidence of both carpal tunnel syndrome and PUnC in cervical radiculopathy was 1.84%. Patients with cervical radiculopathy were more likely than matched controls to have both CTS (P < .001) and PUnC (P < .001). Patients with CTS (P < .001) and with PUnC (P < .001) were more likely to have cervical radiculopathy than the control cohort.

CONCLUSIONS

The incidence of DCS is reported. Patients with cervical radiculopathy are more likely than matched controls to have peripheral nerve compression, and vice versa, in support of the DCS hypothesis.

Outcomes of ulnar nerve decompression for double crush syndrome

BACKGROUND

Double crush syndrome (DCS) of the ulnar nerve, including cubital tunnel syndrome with ulnar tunnel syndrome (UTS), is uncommon. This study compares the postoperative outcomes of patients with isolated ulnar tunnel syndrome versus those with double crush syndrome of the elbow and ulnar tunnel.

METHODS

This study enrolled 22 patients: 12 underwent cubital tunnel surgery and ulnar tunnel surgery (double crush group); and 10 underwent only ulnar tunnel decompression (isolated UTS group). Postoperative effect evaluation of patients in both groups after at least 2.6 years (mean, 5.1 years and 5.7 years, respectively). Statistical analysis compared postoperative function, physical examination, and patient-reported satisfaction between groups.

RESULTS

In terms of postoperative grip strength, there was no difference between the postoperative states of the two groups (0.88 ± 0.04 versus 0.87 ± 0.05), while there was statistical difference in terms of the increment of the grip strength (p = 0.036); the two-point discrimination of isolated UTS group is better than the double crush group (90% versus 83.3%); double crush patients reported lower satisfaction than the UTS group (90% versus 83.3%).

CONCLUSIONS

At a minimum of 2.6 years after the nerve decompression, the patients of isolated UTS group are likely to have superior grip strength increment than patients with a history of double crush surgery, and there is no big difference in the final recovery situation. The sensation and satisfaction of isolated UTS group after nerve release were better compared with patients following double crush surgery.

Patients With and Without Double Crush Syndrome Achieve Similar Rates of Clinical Improvement Following Carpal Tunnel Release

BACKGROUND

The purpose of this study is to compare outcomes of carpal tunnel release (CTR) in patients with and without double crush syndrome (DCS), defined as concurrent carpal tunnel syndrome (CTS) and cervical radiculopathy at C5-T1 on preoperative nerve conduction studies.

METHODS

Patients with preoperative nerve conduction studies who underwent unilateral, isolated CTR were retrospectively identified. All patients completed preoperative and 3-month postoperative Patient-Reported Outcomes Measurement Information System (PROMIS) upper extremity (UE) and pain interference (PI), and Disabilities of the Arm, Shoulder and Hand (QuickDASH) questionnaires, and responded to the anchor question: "Since your treatment, how would you rate your overall function?" (much worse, worse, slightly worse, no change, slightly improved, improved, much improved). Preoperative, postoperative, and changes in scores for UE, PI, and QuickDASH were compared, as were the anchor question responses and rates of achieving the minimal clinically important difference (MCID).

RESULTS

Sixty-three patients with DCS and 115 patients with CTS only were included. At 3- to 4-month follow-up, absolute and change in UE, PI, and QuickDASH scores were not statistically different between patients with DCS and CTS. Rates of anchor question response and MCID achievement were comparable for patients with CTS only and DCS on each questionnaire. The MCID achievement ranged from 48.4% to 68.8% in the unmatched cohort and 48.4% to 60% in the matched group.

CONCLUSIONS

At 3 to 4 months, patients with DCS experience similar patient-reported symptomatic and functional improvement, and achieve MCID of outcome measures at comparable rates to patients with CTS only. For patients with nerve compression at the carpal tunnel and cervical spine, CTR is a reasonable first step prior to proceeding with cervical spine decompression.

Postoperative Functional Analysis of Double Crush Versus Single Peripheral Nerve Decompression: A Retrospective Study

BACKGROUND

Double crush (DC) syndrome patients presenting with C6-7 radiculopathy and median nerve compression in the carpal tunnel report greater nerve irritability and weakness postdecompression than isolated peripheral nerve decompression. We hypothesize that patient-reported outcome is inferior following release at both cervical spine and wrist versus a single site of decompression.

METHODS

Patients that underwent either anterior cervical decompression and fusion (ACDF) for C6-C7 radiculopathy, carpal tunnel release (CTR), or both within 5 years (DC) were identified. A total of 477 patients were analyzed (157 DC, 203 CTR, and 117 ACDF). Post-operative outcome Disabilities of the Arm, Shoulder, and Hand (QuickDASH), Neck Disability Index, and visual analog scale (VAS) scores were collected at an average of 2 years postoperatively.

RESULTS

QuickDASH scores were higher in the DC group versus CTR group (36 vs 22, P < .0002). Postoperative disability in the ACDF group was significantly higher than the DC group (50 vs 36, P < .017). There were no differences between ACDF and DC groups in arm pain intensity, but the CTR group demonstrated significantly greater arm pain intensity than the DC group (5.7 vs 3.6, 10-point scale, P < .01).

CONCLUSIONS

Patients undergoing ACDF and CTR have greater postoperative disability than those undergoing CTR alone, but less postoperative functional disability and pain than ACDF alone, indicating cervical radiculopathy may contribute a greater proportion of long-term disability postoperatively. Additionally, CTR had greater postoperative arm pain than DC patients, potentially indicating high rates of undiagnosed cervical radiculopathy or other sources of arm pain in these patients.

The prevalence of double- and multiple crush syndromes in patients surgically treated for peripheral nerve compression in the upper limb

OBJECTIVE

The double crush syndrome describes a condition characterized by multifocal entrapment of a nerve. In the upper limb, the high prevalence of carpal tunnel syndrome makes it a common diagnosis of assumption in the setting of median neuropathy. More proximal compressions may tend to be overlooked, under-diagnosed and under-treated in the population. This study aims to map the prevalence of peripheral upper limb nerve compressions among patients undergoing peripheral nerve decompression.

METHODS

A prospective case series was conducted on 183 patients undergoing peripheral nerve decompression in a private hand surgery clinic. Level(s) of nerve compression in the median, ulnar and radial nerves were determined by history and physical examination. The prevalence of each nerve compression syndrome or combination of syndromes was analyzed.

RESULTS

A total of 320 upper limbs in 183 patients were analyzed. A double crush of the median nerve at the levels of the lacertus fibrosus and carpal tunnel was identified in 78% of upper limbs with median neuropathy, whereas isolated lacertus syndrome and carpal tunnel syndrome were present in only 5% and 17% of affected limbs respectively. Cubital tunnel syndrome affected 12.5% of upper limbs, and 80% of these had concomitant lacertus and carpal tunnel syndromes, compared to only 7.5% with isolated cubital tunnel syndrome.

CONCLUSION

A high prevalence should prompt clinicians towards more routine assessment for double crush syndrome to avoid misdiagnosis, inadequate treatment, recurrence, and revision surgeries.

Subacute Ulnar Nerve Compression Neuropathy Following Hand Crush Injury in the Setting of Intracanal Accessory Abductor Digiti Minimi: A Double Crush Phenomenon

Anatomical variations within Guyon's canal such as an accessory abductor digiti minimi are described as causes of ulnar nerve compression. Here we present a unique case of delayed ulnar neuropathy following treatment of left fourth metacarpal base fracture with percutaneous pinning fixation and an uncomplicated two month postoperative course. He returned with new ulnar sensory loss and motor weakness. EMG demonstrated nerve compression with CT identifying an accessory abductor digiti minimi in Guyon's canal. Following Guyon's canal release with partial accessory muscle resection, there was immediate sensory and progressive motor recovery with resolution of clawing. Delayed compression by an accessory abductor digiti minimi following trauma has not been described, suggestive of double-crush phenomenon. The accessory muscle was an asymptomatic variable (first "crush") and with the second "crush" of post-surgical changes resulting in pathological nerve compression. With delayed onset ulnar neuropathy after trauma, surgeons should consider possible accessory structures.

Molecular Insights of Plant Phytochemicals Against Diabetic Neuropathy

Diabetes and its associated complications including diabetic neuropathy have become a menacing headache for health workers and scientists all over the world. The number of diabetic individuals has been growing exponentially every day while the entire medical fraternity feels crippled and unable to handle such an enormous and anarchical scenario. The disease also demonstrates itself in the patients in numerous ways ranging from a little discomfort to death. Diabetic neuropathy has a poor prognosis since it might go unnoticed for years after the onset of diabetes. The etiology of the disease has been linked to oxidative stress caused by increased free radical production. Hyperglycemia causes multiple metabolic pathways to be activated, as well as significant oxidative stress, which becomes the major cause of cell death, culminating in Diabetic Neuropathy. So, it is the need of the hour to find out permanent treatment for this life-threatening disease. The primary goal of this study is to emphasize the potential importance of numerous processes and pathways in the development of diabetic neuropathy as well as the possible role of plant metabolites to control the disease at a molecular level. A possible mechanism was also summarized in the study about scavenging the reactive oxygen species by a flavonoid component. The study also covered the in vivo data of various plants and some of the flavonoid compounds actively studied against Diabetic Neuropathy by inhibiting or reducing the contributing factors such as proinflammatory cytokines, ROS, RNS inhibition, and upregulating the various cellular antioxidants such as GSH, SOD, and CAT.

Patients having surgery for ulnar nerve compression at the elbow rarely have affection of the spinal nerve root at C8-Th1 levels

Cervical pathology may contribute to residual problems after surgery for ulnar nerve compression. We aimed to evaluate the presence of pathological conditions in spinal cord and cervical spinal nerve roots in patients surgically treated for ulnar nerve compression at elbow. In a cohort of patients, surgically treated for ulnar nerve compression at elbow, magnetic resonance images (MRI; performed 3 years pre/postoperatively) were evaluated by a neuroradiologist blinded to patient characteristics and outcome of surgery. Cervical conditions were assessed and related to patient characteristics, preoperative McGowan grade, and outcome. Among 62 patients (45 unilaterally and 17 bilaterally), only one had spinal nerve root affection of nerve roots contributing to the ulnar nerve (C8-Th1). About half of the patients, mainly those at higher age, had alterations affecting C3-C7 spinal nerve roots at both surgically treated and contralateral, non-surgically treated, sides. Only few other changes were observed at cervical levels. A high McGowan grading was related to a high frequency of spinal nerve root affection. Smokers were more frequently observed among those with spinal nerve root affection at C3-C7 levels at surgically treated side. Residual problems, expressed as patient dissatisfaction and DASH score ≥40, were common. Spinal nerve roots, contributing to the ulnar nerve, are rarely affected in surgically treated patients with ulnar nerve compression at elbow even though pathology is often observed at other cervical levels. Pathology is often detected at other cervical spinal nerve root levels at surgically treated and contralateral sides, particularly among older patients, smokers, and in conjunction with worse preoperative McGowan grade. No relation between cervical pathology and outcome of ulnar nerve surgery is seen.

10 Hypotheses in Hand Surgery

I have put together 10 topics and labeled them as hypotheses, which outline my preferred practices. The topics relate to questionable nerve compression, double crush syndrome of nerves, motion therapy after surgery, delayed primary tendon repair, proximal pole fracture of the scaphoid, short splint, and indications for postoperative hand elevation. I found no proof whether my preferred methods are better than or inferior to alternative methods that others use. The 10 hypotheses are presented to stimulate thinking, clinical observation, or investigations and highlight several areas of research. Investigation into these hypotheses may avoid unnecessary treatment or improve postsurgical comfort for patients and long-term outcomes of treatment.

Double Crush Syndrome of the Upper Extremity

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The double crush hypothesis originally proposed that compression of a peripheral nerve at a proximal site increases its susceptibility to additional distal lesions.

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The etiology of double crush syndrome is likely multifactorial as mechanical, systemic, pharmacologic, or environmental factors may increase a patient's susceptibility to this syndrome.

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To date, there remains no standardized definition of double crush syndrome, and there is no consensus on its exact pathophysiology or diagnostic criteria.

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Patients with double crush syndrome should be counseled that surgical repair may produce inferior outcomes compared with those who are treated for isolated entrapment neuropathies.

Double crush syndrome: Epidemiology, diagnosis, and treatment results

BACKGROUND

Double Crush Syndrome (DCS) is a clinical condition that involves multiple compression sites along a single peripheral nerve. The present study aims to describe the epidemiology of DCS and surgical results.

METHODS

A retrospective observational analytic study included patients with clinical diagnosis of cervical radiculopathy and carpal tunnel syndrome who underwent surgery between January 2009 and January 2019. General demographic characteristics were noted, and 3 groups were distinguished: spinal surgery, carpal tunnel release, and bimodal decompression (BD); statistical differences were analyzed between them.

RESULTS

The sample comprised 32 patients. DCS prevalence was 10.29%. Mean age at presentation was 59.25±10.98 years. There was female predominance (75%). Paresthesia was the main symptom (65.6%). Post-surgical results of BD showed significant improvement in sensory nerve conduction velocity, motor nerve conduction velocity (both P=0.008), and disability on Douleur Neuropathique 4 questions, Neck Disability Index, and Boston Carpal Tunnel Questionnaire (P=0.001, 0.004, 0.008, respectively).

CONCLUSIONS

Diagnosis and management of DCS are a challenge. It is necessary to determine the site with maximal compression and risk of complications to decide on treatment. If first-line surgery is adequate, proximal and distal symptomatology can be improved. To maximize success, we recommend BD, according to the present results.

Neuromuscular Mimics of Entrapment Neuropathies of Upper Extremities

Introduction: Carpal tunnel syndrome and ulnar neuropathy are such common maladies affecting the upper extremties that they often become the default diagnosis when patients complain of numbness, pain, or weakness of the hands. While often correct, there are a number of other conditions that can also cause sensory or motor loss of the hands, which should be considered when appropriate, as they can mimic upper extremity entrapment syndromes. Methods: In this review, we will discuss such mimics, including Charcot-Marie-Tooth disease, multifocal motor neuropathy, hereditary neuropathy with pressure palsies, mononeuropathy multiplex, Lewis-Sumner syndrome, brachial plexitis (Parsonage-Turner syndrome), myotonic dystrophy, inclusion body myopathy, and distal myopathy of Welander. We will discuss the clinical presentation, as well as diagnostic testing, treatment (if available), and prognosis. Conclusion: The objective is to provide a differential diagnosis for those patients who do not fit well clinically or respond to usual therapy for entrapment neuropathy of the upper extremities.

Presentation and Treatment of a Combined Median Nerve Schwannoma and a C7 Discogenic Radiculopathy

Cervical radiculopathy and peripheral nerve pathology often compete in the differential diagnosis of extremity pain, weakness, and numbness, and frequently, coexist. In this report, we describe a 73-year-old male with a previously asymptomatic left anteromedial proximal upper arm mass, who presented with progressive radicular arm pain, proximal and distal upper extremity weakness, and hand numbness. Clinical investigation revealed a prominent C6-7 disc herniation and a median nerve sheath tumor, with electromyography (EMG)/nerve conduction velocity (NCV) studies suggestive of acute radiculopathy. He was treated in a staged surgical fashion, with the nerve sheath tumor resection first, followed by a standard C6-7 anterior cervical discectomy and fusion (ACDF) two weeks later. The patient made a full recovery. We provide a literature review and discussion of the "double crush" hypothesis.

Investigation of the Effect of Cervical Radiculopathy on Peripheral Nerves of the Upper Extremity With High-Resolution Ultrasonography

STUDY DESIGN

Prospective, cross-sectional observational study.

OBJECTIVE

We aimed to investigate the effects of chronic cervical radiculopathy (CR) on the cross-sectional area (CSA) values of the cervical nerve roots (CNRs), median, ulnar, and radial nerves with high-resolution ultrasonography.

SUMMARY OF BACKGROUND DATA

Symptomatic nerve roots are wider than asymptomatic nerve roots due to the presence of edema. Peripheral nerves have also been shown to develop edema, fibrosis, and changes distal to the affected nerve as a result of mechanical compression. In addition according to "double-crush syndrome" hypothesis, the peripheral nerves are more sensitive to pressure, and a proximal nerve lesion makes the distal segment of the nerve more susceptible to anatomic deterioration by causing interruption in the axoplasmic conduction due to compression.

METHODS

Forty patients with chronic CR were included to the study. Both affected CNRs and the contralateral nerve roots (control group) were evaluated with high-resolution ultrasonography. Ulnar and median nerve CSA measurements were performed at four measurement points and radial nerve measurements at a single measurement point.

RESULTS

CSA measurements were statistically significantly higher at the CNR of the affected side compared to the unaffected side. There was no statistically significant difference when affected and unaffected sides were compared in terms of measurements performed from median, ulnar, and radial nerves at all measurement points.

CONCLUSION

The results of the present study indicate that the changes in the CNR caused by CR do not have any effect on the peripheral nerves. We did not find any affection in peripheral nerve CSA that might have been suggestive of double-crush syndrome in CR.

LEVEL OF EVIDENCE

2.

Case-study of a user-driven prosthetic arm design: bionic hand versus customized body-powered technology in a highly demanding work environment

BACKGROUND

Prosthetic arm research predominantly focuses on "bionic" but not body-powered arms. However, any research orientation along user needs requires sufficiently precise workplace specifications and sufficiently hard testing. Forensic medicine is a demanding environment, also physically, also for non-disabled people, on several dimensions (e.g., distances, weights, size, temperature, time).

METHODS

As unilateral below elbow amputee user, the first author is in a unique position to provide direct comparison of a "bionic" myoelectric iLimb Revolution (Touch Bionics) and a customized body-powered arm which contains a number of new developments initiated or developed by the user: (1) quick lock steel wrist unit; (2) cable mount modification; (3) cast shape modeled shoulder anchor; (4) suspension with a soft double layer liner (Ohio Willowwood) and tube gauze (Molnlycke) combination. The iLimb is mounted on an epoxy socket; a lanyard fixed liner (Ohio Willowwood) contains magnetic electrodes (Liberating Technologies). An on the job usage of five years was supplemented with dedicated and focused intensive two-week use tests at work for both systems.

RESULTS

The side-by-side comparison showed that the customized body-powered arm provides reliable, comfortable, effective, powerful as well as subtle service with minimal maintenance; most notably, grip reliability, grip force regulation, grip performance, center of balance, component wear down, sweat/temperature independence and skin state are good whereas the iLimb system exhibited a number of relevant serious constraints.

CONCLUSIONS

Research and development of functional prostheses may want to focus on body-powered technology as it already performs on manually demanding and heavy jobs whereas eliminating myoelectric technology's constraints seems out of reach. Relevant testing could be developed to help expediting this. This is relevant as Swiss disability insurance specifically supports prostheses that enable actual work integration. Myoelectric and cosmetic arm improvement may benefit from a less forgiving focus on perfecting anthropomorphic appearance.

Multifocal Neuropathy: Expanding the Scope of Double Crush Syndrome

Double crush syndrome (DCS), as it is classically defined, is a clinical condition composed of neurological dysfunction due to compressive pathology at multiple sites along a single peripheral nerve. The traditional definition of DCS is narrow in scope because many systemic pathologic processes, such as diabetes mellitus, drug-induced neuropathy, vascular disease and autoimmune neuronal damage, can have deleterious effects on nerve function. Multifocal neuropathy is a more appropriate term describing the multiple etiologies (including compressive lesions) that may synergistically contribute to nerve dysfunction and clinical symptoms. This paper examines the history of DCS and multifocal neuropathy, including the epidemiology and pathophysiology in addition to principles of evaluation and management.

Frequency of Radiculopathy in Patients With Carpal Tunnel Syndrome and Paracervical Pain

OBJECTIVES

Patients with carpal tunnel syndrome (CTS) and paracervical pain (PCP) are often incorrectly diagnosed with cervical radiculopathy. The objective of the study is to determine how frequently such patients have electrophysiologic evidence of radiculopathy.

METHODS

We reviewed charts of patients with clinical features of CTS and at least 1 median nerve conduction parameter showing slowing across the wrist. Patients were divided into those with and without PCP. Radiculopathy was defined electrophysiologically. We assessed group differences in the frequency of radiculopathy and how radiculopathy frequency varied with median nerve entrapment severity.

RESULTS

Of 108 patients meeting criteria, 56 had PCP and 52 did not. Eight of 56 patients with PCP and 4 of 52 without pain had cervical radiculopathy (P = 0.36). There was no difference in the frequency of radiculopathy related to the severity of median nerve entrapment (P = 0.64).

DISCUSSION

In patients with CTS, PCP is not associated with cervical radiculopathy. Cervical radiculopathy is not more frequent in more severe CTS.

The quantitative relationship between physical examinations and the nerve conduction of the carpal tunnel syndrome in patients with and without a diabetic polyneuropathy

OBJECTIVE

To understand the quantitative correlation between the clinical severity and physical examinations along with the electrodiagnostic findings by subjects with carpal tunnel syndrome (CTS) and also the influence of diabetic polyneuropathy (DPN) on physical examinations by subjects with CTS.

METHODS

Among 200 patients suffering from hand tingling sensations, 68 patients were diagnosed with CTS on at least one hand by nerve conduction tests. Therefore, the Phalen test (PT), hand elevation test (HET), Tinel sign (TS) results were recorded on both hands. The physical examination grades were compared with the electrophysiological CTS grades in 126 hands of 68 patients. Also the comorbidity effect of DPN to CTS was evaluated. For the evaluation of the severity correlations between CTS, PT, HET, and TS, the Spearman analysis was used. An attempt was started to create a formula which could depict the electrophysiological severity of CTS.

RESULTS

Out of the 68 tested subjects, 31 were diagnosed with both DPN and CTS, and 37 with CTS only. Both PT and HET correlated well with the severity of CTS where the correlation of PT was higher than that of HET. The formula were the motor distal latency (MDL)=(72.4-PT)/5.3 and MDL=(76-HET)/7.2. Both PT and HET showed in the presence of DPN a relatively higher relation with CTS without significance.

CONCLUSION

PT and HET would be useful screening tools for the diagnosis and treatment of CTS as the grade of PT and HET present the severity of CTS well. During this study, a formula was created expecting the severity of nerve conduction study with PT and HET through the time domain value of physical examinations.

The double crush syndrome revisited--a Delphi study to reveal current expert views on mechanisms underlying dual nerve disorders

A high prevalence of dual nerve disorders is frequently reported. How a secondary nerve disorder may develop following a primary nerve disorder remains largely unknown. Although still frequently cited, most explanatory theories were formulated many years ago. Considering recent advances in neuroscience, it is uncertain whether these theories still reflect current expert opinion. A Delphi study was conducted to update views on potential mechanisms underlying dual nerve disorders. In three rounds, seventeen international experts in the field of peripheral nerve disorders were asked to list possible mechanisms and rate their plausibility. Mechanisms with a median plausibility rating of ≥7 out of 10 were considered highly plausible. The experts identified fourteen mechanisms associated with a first nerve disorder that may predispose to the development of another nerve disorder. Of these fourteen mechanisms, nine have not previously been linked to double crush. Four mechanisms were considered highly plausible (impaired axonal transport, ion channel up or downregulation, inflammation in the dorsal root ganglia and neuroma-in-continuity). Eight additional mechanisms were listed which are not triggered by a primary nerve disorder, but may render the nervous system more vulnerable to multiple nerve disorders, such as systemic diseases and neurotoxic medication. Even though many mechanisms were classified as plausible or highly plausible, overall plausibility ratings varied widely. Experts indicated that a wide range of mechanisms has to be considered to better understand dual nerve disorders. Previously listed theories cannot be discarded, but may be insufficient to explain the high prevalence of dual nerve disorders.

[Diagnostic pitfalls in carpal tunnel syndrome]

BACKGROUND

This review focuses on the main aspects of positive and differential diagnosis of carpal tunnel syndrome (CTS) in different clinical situations encountered in daily practice.

STATE OF THE ART

Authentic CTS can be discovered in situations, which alter the usual presentation or therapeutic management. This is the case for instance in pregnant women or in the elderly subject or with acute motor forms where CTS discloses a focal intratunnel disorder (neuroma, lipoma, arterial condition, bone disorder) or a general disease (hereditary neuropathy, amylosis). In certain situations, the clinical manifestations suggest a more proximal compression of the medial nerve (round pronator, Struthers arcade, or superficial flexor) or an inflammatory condition (mononeuritis, inflammatory demyelinising neuropathy). Locoregional disease may also be involved, for instance a plexus (thoracobrachial outlet syndrome, post-radiation plexitis) or radicular condition. The clinical presentation of diffuse polyneuropathy with initial manifestations involving the upper limb (ganglioneuropathies, polyradiculoneuritis, small-fiber neuropathies) may also be misleading. Finally central conditions can sometimes be confused with CTS.

CONCLUSION

A rigorous physical examination and an electroneuromyogram are determining to avoid diagnostic pitfalls.

Screening for head, neck, and shoulder pathology in patients with upper extremity signs and symptoms

NARRATIVE REVIEW: Conditions of the head, neck, thorax, and shoulder may occur simultaneously with arm pathology or produce symptoms perceived by the patient to originate in the elbow, wrist, or hand. Identification of the tissue disorder and associated impairments, followed by matching the rehabilitative intervention to address these issues, leads to optimal outcomes. With this goal in mind, the hand therapist needs to recognize clinical findings that signal potentially serious medical conditions of the brain, cervical region, chest, or shoulder. Additionally, less serious but potentially debilitating, musculoskeletal or neurogenic pain from proximal sources must also be differentiated from somatic pain originating in the elbow, wrist, or hand so that the clinician can decide to further examine and intervene or refer to an appropriate health care provider. This article describes clinical findings that suggest the presence of serious medical pathology in the head, neck, or thorax and presents a screening algorithm to assist in discriminating pain derived from local structures in the distal arm from referred pain originating in the more proximal regions of the shoulder, thorax, neck, or brain.

LEVEL OF EVIDENCE

5.

Cubital tunnel surgery in patients with cervical radiculopathy: double crush syndrome?

To determine differences in clinical outcomes in patients harboring both cubital tunnel syndrome (CuTS) and cervical radiculopathy and the influence of the so-called double crush syndrome. Both procedures were performed in 24 patients, mean age 55 years; first group of 14 patients underwent CuTS surgery as a first procedure. Second group of 10 patients underwent anterior cervical discectomy and fusion (ACDF) then ulnar nerve release (UNR). Two patients underwent bilateral nerve surgery and six multiple cervical discectomies. Surgeries consisted in 26 nerve releases with associated external neurolysis in five, and 34 ACDF procedures, with plating in six. Clinical complaints (mean time 12 months) were sensory in 20 arms, with associated motor weakness and hypothenar atrophy involvement in another six. Electromyography changes were mild (two arms), moderate (16 arms), and severe (eight arms). Mean time of follow-up was 3 years (range 18 months-14 years). Clinical improvement was evidenced in 14 patients. Sensory nerve symptoms improved in 13 limbs in both groups and motor improvement was evident in three patients with UNR as first surgery. A comparative cohort of 20 patients with UNR but without cervical radiculopathy was studied to disclose outcome differences. Of these, 13 patients had clinical improvement. No differences were found among groups. In patients with double crush syndrome, factors that seemed to influence a poor CuTS outcome were evolution of symptoms longer than a year, history of multiple neuropathies or radiculopathies, and ACDF performed before UNR.

Neurophysiological study to assess the severity of each site through the motor neuron fiber in entrapment neuropathy

Background

The double crush hypothesis (DCH) that had been widely accepted seems to have been dismissed recently. Prior to the DCH, retrograde changes in the proximal median nerve in carpal tunnel syndrome (CTS) were reported. There has been no report of quantitative analyzing about the effect of one site's compression on another site all through the same peripheral nerve in CTS patients.

Methods

We measured the central motor conduction time (CMCT), motor conduction latency of the cervical root region (CRL), peripheral path latency from the rootlet to the wrist (PL) and motor distal latency (MDL) in the median nerve and ulnar nerves, respectively in CTS patients.

Results

MDL, PL and CRL were prolonged selectively in the median nerve, but not in the ulnar nerve of CTS patients. And in the median nerve measurement, MDL was high (r = 0.59, p < 0.0001) while PL showed a significant (r = -0.28, p < 0.05) relationship with CRL. MDL was large (r = 0.58, p < 0.0001) and showed a close (r = 0.59, p < 0.0001) relationship with the amplitude of CMAP. There was no significant difference between the amplitude of the normal CRL group and that of the prolonged CRL group. This quantitative analysis showed a linear relationship among MDL, CRL and CMAP amplitude.

Conclusion

Dual entrapment lesions did not unexpectedly exaggerate the vulnerability or total damage. The vulnerability and the damage were proportional to the severity of each lesion. If the DCH term presented to an unexpectedly exaggerated degree, the cases of double crush symdrome in the CTS patients were rare, but if the term DCH refers to only this linear relationship, the DCH should not be dismissed.

Effects of traditional cupping therapy in patients with carpal tunnel syndrome: a randomized controlled trial

We investigated the effectiveness of cupping, a traditional method of treating musculoskeletal pain, in patients with carpal tunnel syndrome (CTS) in an open randomized trial. n = 52 outpatients (58.5 +/- 8.0 years) with neurologically confirmed CTS were randomly assigned to either a verum (n = 26) or a control group (n = 26). Verum patients were treated with a single application of wet cupping, and control patients with a single local application of heat within the region overlying the trapezius muscle. Patients were followed up on day 7 after treatment. The primary outcome, severity of CTS symptoms (VAS), was reduced from 61.5 +/- 20.5 to 24.6 +/- 22.7 mm at day 7 in the cupping group and from 67.1 +/- 20.2 to 51.7 +/- 23.9 mm in the control group [group difference -24.5mm (95%CI -36.1; -2.9, P < .001)]. Significant treatment effects were also found for the Levine CTS-score (-.6 pts: 95%CI -.9; -.2, P = .002), neck pain (-12.6mm; 95%CI -18.8; -6.4, P < .001), functional disability (DASH-Score) (-11.1 pts; 95%CI -17.1; -5.1, P < .001), and physical quality of life (.3; 95%CI .0; .3, P = .048). The treatment was safe and well tolerated. We conclude that cupping therapy may be effective in relieving the pain and other symptoms related to CTS. The efficacy of cupping in the long-term management of CTS and related mechanisms remains to be clarified.

PERSPECTIVE

The results of a randomized trial on the clinical effects of traditional cupping therapy in patients with carpal tunnel syndrome are presented. Cupping of segmentally related shoulder zones appears to alleviate the symptoms of carpal tunnel syndrome.

Carpal tunnel syndrome and the "double crush" hypothesis: a review and implications for chiropractic

Upton and McComas claimed that most patients with carpal tunnel syndrome not only have compressive lesions at the wrist, but also show evidence of damage to cervical nerve roots. This "double crush" hypothesis has gained some popularity among chiropractors because it seems to provide a rationale for adjusting the cervical spine in treating carpal tunnel syndrome. Here I examine use of the concept by chiropractors, summarize findings from the literature, and critique several studies aimed at supporting or refuting the hypothesis. Although the hypothesis also has been applied to nerve compressions other than those leading to carpal tunnel syndrome, this discussion mainly examines the original application - "double crush" involving both cervical spinal nerve roots and the carpal tunnel. I consider several categories: experiments to create double crush syndrome in animals, case reports, literature reviews, and alternatives to the original hypothesis. A significant percentage of patients with carpal tunnel syndrome also have neck pain or cervical nerve root compression, but the relationship has not been definitively explained. The original hypothesis remains controversial and is probably not valid, at least for sensory disturbances, in carpal tunnel syndrome. However, even if the original hypothesis is importantly flawed, evaluation of multiple sites still may be valuable. The chiropractic profession should develop theoretical models to relate cervical dysfunction to carpal tunnel syndrome, and might incorporate some alternatives to the original hypothesis. I intend this review as a starting point for practitioners, educators, and students wishing to advance chiropractic concepts in this area.

Double crush syndrome: an analysis of age, gender and body mass index

OBJECTIVES

The aim of this study is to evaluate the role of age, gender, body mass index (BMI), wrist ratio and median sensory nerve conduction velocity as independent risk factors for double crush syndrome (DCS) and to analyze the strength of association of these factors.

PATIENTS AND METHODS

We have undertaken a case-control study in 142 patients (125 females) with carpal tunnel syndrome (CTS) and 109 controls. Based on clinical and electrophysiologic criteria 106 pure CTS patients and 36 DCS patients as well as 62 female and 47 male control subjects were selected from patients and their relatives referred to our tertiary referral hospital. Totally nerve conduction studies and electromyographic examination were done in 201 hands. Height, weight, BMI, wrist width, depth, circumference and ratio were measured in all patients and control group. Mean values of different risk factors for DCS group and controls were measured. A logistic regression analysis was conducted to evaluate odds ratio of different risk factors.

RESULTS

The mean values for age was greater in DCS patients than CTS group. Male gender and increasing age had odds ratio of 4.19 (CI 95%: 1.35-12.96) and 1.13 (CI 95%: 1.07-1.19), respectively.

CONCLUSION

Our study confirms that male gender and increased age are independent risk factors for DCS. We suggest that in elderly men presenting with CTS, electrophysiologic screening for cervical radiculopathy should be considered because the treatment of DCS differs from pure CTS.

Carpal tunnel syndrome and metabolic syndrome

Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy. Many factors such as diabetes mellitus, hypothyroidism, hormonal replacement therapy, corticosteroid use, rheumatoid arthritis and wrist fractures may cause CTS. Metabolic syndrome includes abdominal obesity, dyslipidemia, hyperglycemia, and hypertension that may cause CTS. In this study, we aimed to evaluate the relation between CTS and metabolic syndrome. We studied 107 (96 female and 11 male) right-handed patients who had a clinical and electrophysiologically confirmed diagnosis of CTS. We then divided the patients into two groups (patients with and without metabolic syndrome) according to the criteria of ATP III definition. Eighty (75%) of the patients with CTS had metabolic syndrome. Among the 80 patients with metabolic syndrome, CTS was found in 150 hands (43 mild, 58 moderate and 49 severe cases). Among the 27 patients without metabolic syndrome, CTS was found in 43 hands (27 mild, 14 moderate and 2 severe cases). The electrophysiological parameters (median nerve distal motor latency, median nerve motor amplitude, median nerve motor conduction velocity, median nerve sensory onset latency, median nerve sensory amplitude and median nerve sensory conduction velocity) were worse in patients with metabolic syndrome (P < 0.05). In conclusion, metabolic syndrome was found to be three times more common in patients with CTS and CTS was more severe in patients with metabolic syndrome when compared with those without metabolic syndrome.

Cervical radiculopathy: pathophysiology, presentation, and clinical evaluation

Cervical radiculopathy is a common condition that usually results from compression and inflammation of the cervical nerve root or roots in the region of the neural foramen. It is frequently caused by cervical disc herniation and cervical spondylosis. The diagnosis can be established by history and physical examination, but care should be taken, as diagnoses can mimic or coexist with cervical radiculopathy, such as entrapment neuropathies. The pathophysiology, presentation, and clinical evaluation of cervical radiculopathy are discussed.

Frequency and severity of carpal tunnel syndrome according to level of cervical radiculopathy: Double crush syndrome?

OBJECTIVE

The double crush hypothesis (DC) proposes that a proximal lesion along an axon predisposes it to injury at a more distal site along its course through impaired axoplasmic flow. The frequency and severity of carpal tunnel syndrome (CTS) according to the level of cervical radiculopathy were investigated to evaluate the hypothesis of DC.

METHODS

The frequency of CTS was investigated in 277 patients with C6, C7 or C8 radiculopathies and correlation between CTS and radiculopathy level was determined. We also investigated whether the degrees of abnormal sensory responses were more severe in C6, C7 radiculopathies and whether motor responses were more severe in C8 radiculopathy.

RESULTS

Thirty-nine patients were diagnosed with CTS and concomitant cervical radiculopathy at the C6, 7, or C8 root levels. The frequency of coexisting CTS was not statistically different according to the level of radiculopathy. The electrophysiologic results revealed no significant correlation between median sensory parameters and C6, C7 cases, and no relationship was observed between median motor responses and C8 radiculopathy.

CONCLUSIONS

The frequency and electrophysiologic data of CTS analyzed according to cervical radiculopathy level do not support a neurophysiological explanation.

SIGNIFICANCE

Based on this study, the DC hypothesis could not be supported.

Effects of Reduction Mammoplasty on Upper-Limb Nerve Conduction Across the Thoracic Outlet in Women With Macromastia

Macromastia is a common problem. The physical complaints include upper body pain and aches. There have been anecdotal reports of neurologic deficits in the nerves emanating from the lower trunk of the brachial plexus. This is thought to be due to pressure on the lower trunk from both the first rib and tilting forward of the coracoid process. Other anecdotal reports have centered on the correction of neuropraxia of the ulnar nerve following bilateral breast reduction (BBR). We investigate the effect of BBR on the electrophysiological function of the nerve supply to the upper limbs in women with macromastia.

METHODOLOGY

Consecutive patients undergoing BBR were randomized into 2 groups, depending on time of surgery. None had any prior neurologic disorder. Each patient had a comprehensive neurologic assessment and 2 electrodiagnostic neurophysiologic tests. Group 1 had 2 tests, one before surgery and a second 3 months postsurgery, while Group 2 had 2 sets of tests, one initially and a second test 4 months later (control). The outcome measures include somatosensory evoked potential (SSEP) (median and ulnar), F-wave median and ulnar latencies. The F waves measure the integrity of neural conduction time from the anterior horn cells to the hypothenar and thenar muscles reflecting lower trunk function. The SSEP of the median nerve measure the integrity of the nerve fibers traversing the upper trunk of the brachial plexus and the ulnar nerve SSEP that of the lower trunk. There was no statistical difference in the conduction times. BBR does not have any effect on the upper limb nerve conduction times.

Development of a clinical prediction rule for the diagnosis of carpal tunnel syndrome

OBJECTIVES

To develop a clinical prediction rule (CPR) and to assess the reliability and diagnostic accuracy of individual clinical examination items for the diagnosis of carpal tunnel syndrome (CTS).

DESIGN

Prospective diagnostic test study with blind comparison to a reference criterion of a compatible clinical presentation and abnormal electrophysiologic findings.

SETTING

Multicenter medical center and community hospital with patient referrals from ambulatory primary care and specialty practice settings.

PARTICIPANTS

Eight-two consecutively referred patients (50% men; mean age, 45+/-12 y) with suspected cervical radiculopathy or CTS referred for electrophysiologic examination.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Sensitivity, specificity, and likelihood ratios.

RESULTS

The CPR identified in this study consisted of 1 question (shaking hands for symptom relief), wrist-ratio index greater than .67, Symptom Severity Scale score greater than 1.9, reduced median sensory field of digit 1, and age greater than 45 years. The likelihood ratio for the CPR was 18.3 when all 5 tests were positive. Interrater reliability was acceptable for all but 2 clinical examination items.

CONCLUSIONS

The CPR identified was more useful for the diagnosis of CTS than any single test item and resulted in posttest probability changes of up to 56%. Further investigation is required both to validate the test-item cluster and to improve point-estimate precision.

What symptoms are truly caused by median nerve compression in carpal tunnel syndrome?

OBJECTIVE

This study aims to identify the symptoms, signs and distributions which are associated with neurophysiological carpal tunnel syndrome (N-CTS), defined by the finding of a median nerve lesion at the wrist through neurophysiologic studies, and to compare them with those of patients with sensory or motor complaints in the upper limbs whose electrophysiologic investigation did not show evidence of this syndrome.

METHODS

A cross-sectional study was performed, with prospective gathering of data, following a predetermined protocol. We included all patients older than 12 years who were referred for nerve conduction studies and electromyography of at least one of the upper limbs between August 2001 and January 2003. The patients answered a clinicoepidemiologic questionnaire and painted the areas in which they felt pain and those in which they felt paresthesia, and were also examined to test for classical signs CTS.

RESULTS

A neurophysiological diagnosis of CTS was reached in 1549 upper limbs (39%). Approximately 6% of the upper limbs with N-CTS and 16% of those without median nerve lesion do not have any hand or wrist symptoms (P<0.001). Paresthesia, pain, hand weakness and cramps were the symptoms statistically associated to N-CTS, with paresthesia being the one with the greatest power of association. This is usually felt in median innervation's territory, and is frequently extended to the whole hand, but without association with N-CTS when felt in proximal region.

CONCLUSIONS

One concludes that the most characteristic manifestation of carpal tunnel syndrome (CTS) is paresthesia. Pain also occurs very frequently but it is less specific, and weakness, meanwhile, seems to have a low frequency. We believe that the variability in the clinical presentation of CTS is largely due to the presence of associated diseases and our results provide information which could help to better define the clinical criteria used in the diagnosis of this syndrome.

Double crush syndrome

Nerve entrapment conditions and peripheral neuropathies are sometimes related to injurious events, toxicosis, and repetitive microtrauma to soft tissue and nerve structures. An interesting theory concerning peripheral entrapment neuropathy has been discussed in the literature. This theory is called the double crush syndrome. This article briefly discusses the biologic/metabolic, structural, toxicogenic, and vasculopathic rationale for the pathogenesis of double crush syndrome.