Proximal pain in patients with carpal tunnel syndrome: a clinical-neurophysiological study

Carpal tunnel syndrome

Median neuropathy at the wrist, commonly referred to as carpal tunnel syndrome (CTS), is the most common entrapment neuropathy. It is caused by chronic compression of the median nerve at the wrist within the space-limited carpal tunnel. Risk factors that contribute to the etiology of compression include female gender, obesity, work-related factors, and underlying medical conditions, such as hypothyroidism, pregnancy, and amyloidosis. The diagnosis is made on clinical grounds, although these can be confounded by anatomical variations. Electrodiagnostic studies, which are specific and sensitive in diagnosing CTS, support the diagnosis; however, a subgroup may present with normal results. The advent of imaging techniques, including ultrasound and MRI, further assists the diagnostic process. The management of CTS is divided into the nonsurgical approaches that include hand therapy, splinting and corticosteroid injection, and surgical decompression of the carpal tunnel. Although several surgical techniques have been developed, no one method is more effective than the other. Each of these management approaches are effective at providing symptom relief and are utilized at different severities of the condition. There is, however, a lack of consensus on standardized diagnostic criteria, as well as when and to whom to refer patients for surgery.

Carpal Tunnel Syndrome: Neuropathic Pain Associated or Not with a Nociplastic Condition

Carpal tunnel syndrome (CTS) has been traditionally classified as primarily a neuropathic condition with or without pain. Precision medicine refers to an evidence-based method of grouping patients based on their susceptibility to biology, prognosis of a particular disease, or in their response to a specific treatment, and tailoring specific treatments accordingly. In 2021, the International Association for the Study of Pain (IASP) proposed a grading system for classifying patients into nociceptive, neuropathic, or nociplastic phenotypes. This position paper presents data supporting the possibility of subgrouping individuals with specific CTS related-pain into nociceptive, neuropathic, nociplastic or mixed-type phenotypes. Carpal tunnel syndrome is a neuropathic condition but can also be comorbid with a nociplastic pain condition. The presence of extra-median symptoms and the development of facilitated pain processing seem to be signs suggesting that specific CTS cases can be classified as the nociplastic pain phenotype. The clinical responses of therapeutic approaches for the management of CTS are inconclusive. Accordingly, the ability to identify the predominant pain phenotype in patients with CTS could likely be problematic for producing efficient treatment outcomes. In fact, the presence of a nociplastic or mixed-type pain phenotype would explain the lack of clinical effect of treatment interventions targeting the carpal tunnel area selectively. We propose a clinical decision tree by using the 2021 IASP classification criteria for identifying the predominant pain phenotype in people with CTS-related pain, albeit CTS being a priori a neuropathic pain condition. The identification of a nociplastic-associated condition requires a more nuanced multimodal treatment approach to achieve better treatment outcomes.

Automatic Electrodiagnosis of Carpal Tunnel Syndrome Using Machine Learning

Recent literature has revealed a long discussion about the importance and necessity of nerve conduction studies in carpal tunnel syndrome management. The purpose of this study was to investigate the possibility of automatic detection, based on electrodiagnostic features, for the median nerve mononeuropathy and decision making about carpal tunnel syndrome. The study included 38 volunteers, examined prospectively. The purpose was to investigate the possibility of automatically detecting the median nerve mononeuropathy based on common electrodiagnostic criteria, used in everyday clinical practice, as well as new features selected based on physiology and mathematics. Machine learning techniques were used to combine the examined characteristics for a stable and accurate diagnosis. Automatic electrodiagnosis reached an accuracy of 95% compared to the standard neurophysiological diagnosis of the physicians with nerve conduction studies and 89% compared to the clinical diagnosis. The results show that the automatic detection of carpal tunnel syndrome is possible and can be employed in decision making, excluding human error. It is also shown that the novel features investigated can be used for the detection of the syndrome, complementary to the commonly used ones, increasing the accuracy of the method.

Effects of neural mobilizations through movement representation techniques for the improvement of neural mechanosensitivity of the median nerve region: a randomized controlled trial

PURPOSE

The main objective was to compare the effects of neural mobilization (NM), NM performed through mirror therapy (MT), NM performed through action observation (AO) training and finally classic rehabilitation program (mobility and strength) exercises on neural mechanosensitivity, widespread of proximal and distal pain and pressure pain thresholds (PPT). The second objective was to assess the effects of these interventions on handgrip strength, conditioned pain modulation, motor imagery ability and temporal summation.

MATERIALS AND METHODS

Single-blinded randomized controlled trial. Fifty-four healthy subjects were randomly assigned to each group. Neural mechanosensitivity, widespread pain and PPT were the main variables. The secondary variables included handgrip strength, conditioned pain modulation, motor imagery ability and temporal summation.

RESULTS

All groups showed significant differences in time*factor for neural mechanosensitivity (p = 0.001), PPT in the dermatome of the median nerve (p = 0.007), PPT at carpal tunnel (p < 0.05) and proximal widespread (p = 0.01). No differences were found for distal widespread, conditioned pain modulation, handgrip strength motor imagery ability or temporal summation (p > 0.05). There is an absence of statistically significant differences between groups.

CONCLUSIONS

NM through movement representation techniques can reduce mechanosensitivity and mechanical hyperalgesia in the median nerve dermatome and forearm, although no differences were found between groups.

The Utilization of Joint Mobilization As Part of a Comprehensive Program to Manage Carpal Tunnel Syndrome: A Systematic Review

OBJECTIVE

The purpose of this review is to identify the role of joint mobilization for individuals with Carpal tunnel syndrome (CTS).

METHODS

A systematic search of 5 electronic databases (PubMed, CINAHL, Scopus, Cochrane Central Register of Controlled Trials, and SPORTDiscus) was performed to identify eligible full-text randomized clinical trials related to the clinical question. Joint mobilization had to be included in one arm of the randomized clinical trials to be included. Two reviewers independently participated in each step of the screening process. A blinded third reviewer assisted in cases of discrepancy. The PEDro scale was used to assess quality.

RESULTS

Ten articles were included after screening 2068 titles. In each article where joint mobilization was used, positive effects in pain, function, or additional outcomes were noted. In most cases, the intervention group integrating joint mobilization performed better than the comparison group not receiving joint techniques.

CONCLUSION

In the articles reviewed, joint mobilization was associated with positive clinical effects for persons with CTS. No studies used joint mobilization in isolation; therefore, results must be interpreted cautiously. This review indicates that joint mobilization might be a useful adjunctive intervention in the management of CTS.

Understanding central sensitization for advances in management of carpal tunnel syndrome

Carpal tunnel syndrome is the most common nerve compression disorder of the upper extremity, and it is traditionally considered a peripheral neuropathy associated with a localized compression of the median nerve just at the level of the carpal tunnel. Surgery and physiotherapy are treatment approaches commonly used for this condition; however, conflicting clinical outcomes suggest that carpal tunnel syndrome may be more complex. There is evidence supporting the role of peripheral nociception from the median nerve in carpal tunnel syndrome; however, emerging evidence also suggests a potential role of central sensitization. The presence of spreading pain symptoms (e.g. proximal pain), widespread sensory changes, or bilateral motor control impairments in people presenting with strictly unilateral sensory symptoms supports the presence of spinal cord changes. Interestingly, bilateral sensory and motor changes are not directly associated with electrodiagnostic findings. Other studies have also reported that patients presenting with carpal tunnel syndrome exhibit neuroplastic brainstem change supporting central sensitization. Current data would support the presence of a central sensitization process, mediated by the peripheral drive originating in the compression of the median nerve, in people with carpal tunnel syndrome. The presence of altered nociceptive gain processing should be considered in the treatment of carpal tunnel syndrome by integrating therapeutic approaches aiming to modulate long-lasting nociceptive barrage into the central nervous system (peripheral drive) and strategies aiming to activate endogenous pain networks (central drive).

Disturbance of somatotopic spatial cognition and extra-territorial pain in carpal tunnel syndrome

BACKGROUND

Several studies on carpal tunnel syndrome have reported pain that exists beyond the median nerve territory of the affected hand. However, the mechanism is unknown.

PURPOSE

We investigated the cause of extra-territorial pain by the analysis of clinical assessments and cortical activity using magnetoencephalography.

METHODS

To compare patients with and without extra-territorial pain, fourteen patients with carpal tunnel syndrome were assessed using clinical examination, such as patients' profile, paresthesia, physical tests, and psychological tests. The physical assessment included tactile threshold and static and moving two-point discrimination sensations on digital pulp. Neural activation in the cerebral cortex was also measured using z-scores calculated by magnetoencephalography.

RESULTS

Among fourteen patients, ten patients had pain in the affected median nerve territory only and four patients had extra-territorial pain. When comparing the groups, the static and moving two-point discrimination sensation values in patients with extra-territorial pain were larger than those of patients without the pain (p < 0.05). The supra-marginal gyrus, mid-part of the precentral sulcus, angular gyrus in the left hemisphere, bilateral sensorimotor areas for legs, and bilateral isthmus-cingulate areas showed larger z-scores in patients with extra-territorial pain than in patients without the pain (p < 0.05).

CONCLUSIONS

The static and moving two-point discrimination sensations signify the ability of tactile spatial acuity. Bilateral sensorimotor areas were activated in sites that were not the hand. Furthermore, the inferior parietal lobule in the left hemisphere, which synthesizes and integrates multiple sensations showed high activation. Our findings suggested that the mechanism of extra-territorial pain was associated with dysfunction of spatial cognition.

Peripheral nerve injuries, pain, and neuroplasticity

INTRODUCTION

Peripheral nerve injuries (PNIs) cause both structural and functional brain changes that may be associated with significant sensorimotor abnormalities and pain.

PURPOSE OF THE STUDY

The aim of this narrative review is to provide hand therapists an overview of PNI-induced neuroplasticity and to explain how the brain changes following PNI, repair, and during rehabilitation.

METHODS

Toward this goal, we review key aspects of neuroplasticity and neuroimaging and discuss sensory testing techniques used to study neuroplasticity in PNI patients.

RESULTS

We describe the specific brain changes that occur during the repair and recovery process of both traumatic (eg, transection) and nontraumatic (eg, compression) nerve injuries. We also explain how these changes contribute to common symptoms including hypoesthesia, hyperalgesia, cold sensitivity, and chronic neurogenic pain. In addition, we describe how maladaptive neuroplasticity as well as psychological and personality characteristics impacts treatment outcome.

DISCUSSION AND CONCLUSION

Greater understanding of the brain's contribution to symptoms in recovering PNI patients could help guide rehabilitation strategies and inform the development of novel techniques to counteract these maladaptive brain changes and ultimately improve outcomes.

Carpal tunnel syndrome: just a peripheral neuropathy?

Carpal tunnel syndrome (CTS) is considered just a peripheral neuropathy of the upper extremity associated to the compression of the median nerve. There is evidence suggesting the presence of complex sensitization mechanisms in CTS. These processes are manifested by symptoms in extra-median regions and the presence of bilateral sensory and motor impairments. These sensory and motor changes are not associated to electrodiagnostic findings. The presence of sensitization mechanisms suggests that CTS should not be considered just as a peripheral neuropathy. The presence of altered nociceptive gain processing should be considered for therapeutic management of CTS by considering the application of therapeutic interventions that modulate nociceptive barrage into the CNS.

Nerve conduction studies and EMG in carpal tunnel syndrome: Do they add value?

This paper summarises the views of four experts on the place of neurophysiological testing (EDX) in patients presenting with possible carpal tunnel syndrome, in guiding their treatment, and in reevaluations. This is not meant to be a position paper or a literature review, and heterogeneous viewpoints are presented. Nerve conduction studies should be performed in patients presenting with possible carpal tunnel syndrome to assist diagnosis, and may need to be repeated at intervals in those managed conservatively. There is evidence that local corticosteroid injection is safe and effective for many patients, thereby avoiding or deferring surgical decompression. All patients should undergo EDX studies before any invasive procedure for CTS (injection or surgery). Needle EMG studies are not obligatory, but may be needed in those with severe disease and those in whom an alternate or concomitant diagnosis is suspected.

Are extramedian symptoms associated with peripheral causes in patient with carpal tunnel syndrome? Electrodiagnostic and ultrasonographic study

OBJECTIVE

To evaluate the relationship between extramedian spreading of sensorial symptoms and median and ulnar nerve cross-sectional area (CSA) and to compare the ultrasonographic and electrophysiological findings in patients with carpal tunnel syndrome (CTS) with or without extramedian sensory symptoms.

DESIGN

Cross-sectional study.

MATERIALS AND METHODS

Patients with CTS were divided into two groups as with or without extramedian symptoms and were assessed clinically, electrophysiologically and ultrasonographically by three blind investigators. In electrophysiological tests, median and ulnar nerve conduction studies were performed. Nerve cross-sectional areas were measured at hook of hamate, psiform bone, radio-ulnar joint, one-third distal part of forearm, and medial epicondyle by ultrasonography.

FINDINGS

The study was completed with 61 patients (108 hands). Extramedian symptoms were present in 31 patients (54 hands). Finger grip strength was lower, pain values evaluated with visual analogue scale were higher in patients with extramedian symptoms (p<0.05). There was no statistically significant difference in electrophysiological and ultrasonographic parameters.

CONCLUSION

According to our results, extramedian symptoms are not related to nerve conduction studies or nerve ultrasonography, these symptoms may be explained with central sensitization in patient with CTS.

Patient education for carpal tunnel syndrome: analysis of readability

BACKGROUND

The National Institutes of Health and American Medical Association recommend a sixth grade reading level for patient-directed content. This study aims to quantitatively evaluate the readability of the most commonly used resources for surgical treatment of carpal tunnel syndrome.

METHODS

A web search for "carpal tunnel surgery" was performed using an Internet search engine, and the 13 most popular sites were identified. Relevant, patient-directed articles immediately accessible from the main site were downloaded and formatted into plain text. A total of 102 articles were assessed for readability using ten established analyses: first overall, then by website for comparison.

RESULTS

Patient information about carpal tunnel surgery had an overall average reading level of 13.1. Secondary analysis by website revealed a range of mean readability from 10.8 (high school sophomore level) to 15.3 (university junior level). All sites exceeded the recommended sixth grade reading level.

CONCLUSIONS

Online patient resources for carpal tunnel surgery uniformly exceed the recommended reading level. These are too difficult to be understood by a large portion of American adults. A better understanding of readability may be useful in tailoring more appropriate resources for average patient literacy.

Timing and appropriate use of electrodiagnostic studies

Electrodiagnostic studies are powerful tools used to objectively examine the physiologic status of a nerve. These consist of nerve conduction studies, which directly examine motor and sensory function of the nerve, and electromyography, which examines spontaneous and voluntary motor unit action potentials in the muscle. Together these studies enable characterization, localization, and duration of nerve pathology. Appropriate timing and use of electrodiagnostic studies assist medical providers in treating nerve pathology.

Clinical presentation and manual therapy for upper quadrant musculoskeletal conditions

In recent years, increased knowledge of the pathogenesis of upper quadrant pain syndromes has translated to better management strategies. Recent studies have demonstrated evidence of peripheral and central sensitization mechanisms in different local pain syndromes of the upper quadrant such as idiopathic neck pain, lateral epicondylalgia, whiplash-associated disorders, shoulder impingement, and carpal tunnel syndrome. Therefore, a treatment-based classification approach where subjects receive matched interventions has been developed and, it has been found that these patients experience better outcomes than those receiving non-matched interventions. There is evidence suggesting that the cervical and thoracic spine is involved in upper quadrant pain. Spinal manipulation has been found to be effective for patients with elbow pain, neck pain, or cervicobrachial pain. Additionally, it is known that spinal manipulative therapy exerts neurophysiological effects that can activate pain modulation mechanisms. This paper exposes some manual therapies for upper quadrant pain syndromes, based on a nociceptive pain rationale for modulating central nervous system including trigger point therapy, dry needling, mobilization or manipulation, and cognitive pain approaches.

Increased pain sensitivity is not associated with electrodiagnostic findings in women with carpal tunnel syndrome

OBJECTIVE

To determine the differences in widespread pressure pain and thermal hypersensitivity in women with minimal, moderate, and severe carpal tunnel syndrome (CTS) and healthy controls.

METHODS

A total of 72 women with CTS (19 with minimal, 18 with moderate, and 35 with severe) and 19 healthy age-matched women participated. Pressure pain thresholds were bilaterally assessed over the median, ulnar, and radial nerves, the C5 to C6 zygapophyseal joint, the carpal tunnel, and the tibialis anterior muscle. In addition, warm and cold detection thresholds and heat and cold pain thresholds were bilaterally assessed over the carpal tunnel and the thenar eminence. All outcome parameters were assessed by an assessor blinded to the participant's condition.

RESULTS

No significant differences in pain parameters among patients with minimal, moderate, and severe CTS were found. The results showed that PPT were significantly decreased bilaterally over the median, ulnar, and radial nerve trunks, the carpal tunnel, C5 to C6 zygapophyseal joint, and the tibialis anterior muscle in patients with minimal, moderate, or severe CTS as compared with healthy controls (all, P<0.001). In addition, patients with CTS also showed lower heat pain threshold and reduced cold pain threshold compared with controls (P<0.001). No significant sensory differences between minimal, moderate, or severe CTS were found.

CONCLUSIONS

The similar widespread pressure and thermal hypersensitivity in patients with minimal, moderate, or severe CTS and pain intensity suggests that increased pain sensitivity is not related to electrodiagnostic findings.

Women with carpal tunnel syndrome show restricted cervical range of motion

STUDY DESIGN

A case control, blinded study.

OBJECTIVES

To compare the amount of cervical range of motion in women with minimal, mild/moderate, and severe carpal tunnel syndrome (CTS) to that of healthy control participants. We also assessed the relationships between cervical range of motion and clinical variables related to the intensity and temporal profile of pain within each CTS group.

BACKGROUND

It is plausible that the cervical spine may be involved in individuals with CTS. No study has investigated the relationship between cervical range of motion and symptoms associated with CTS severity.

METHODS

Cervical range of motion was assessed in 71 women with CTS (18 with minimal, 18 with mild/moderate, and 35 with severe signs and symptoms) and in 20 similar, healthy women. Those with CTS were aged 35 to 59 years (mean ± SD, 45 ± 8 years) and those in the healthy group were aged 31 to 60 years (45 ± 8 years). An experienced therapist, blinded to the participants' conditions, used a cervical range-of-motion (CROM) device to assess cervical range of motion. Mixed-model analyses of variance (ANOVAs) were conducted to evaluate the differences in cervical range of motion among the 3 groups of patients with CTS and healthy controls. A corrected P value of less than .025 was used as threshold for significance (Bonferroni correction).

RESULTS

The mixed-model ANOVAs revealed that the individuals with CTS exhibited restricted cervical range of motion compared to healthy controls (P<.001), with no significant differences among the groups with minimal, mild/moderate, or severe CTS (P>.356). A significant negative correlation between pain intensity and cervical spine lateral flexion away from the affected side was identified: the greater the mean pain intensity, the lesser the cervical lateral flexion away from the affected side.

CONCLUSIONS

Women with minimal, mild/moderate, or severe CTS exhibited less cervical range of motion compared to women of a similar age, suggesting that restricted cervical range of motion may be a common feature in individuals with CTS, independent of severity subgroups, as defined by electrodiagnosis. Future research should investigate cervical range of motion as a possible consequence or causative factor of CTS and related symptoms.

Specific mechanical pain hypersensitivity over peripheral nerve trunks in women with either unilateral epicondylalgia or carpal tunnel syndrome

STUDY DESIGN

Case-control study with blinded examiner.

OBJECTIVE

To investigate if pressure pain sensitivity is related to specific nerve trunks in the upper extremity of patients with either unilateral lateral epicondylalgia (LE) or carpal tunnel syndrome (CTS).

BACKGROUND

In the clinical setting, patients with LE tend to exhibit radial nerve trunk tenderness, whereas patients with CTS exhibit median nerve tenderness. No studies have investigated if specific nerve pressure pain hypersensitivity exists in patients with either LE or CTS.

METHODS

Sixteen women with unilateral LE (mean±SD age, 43±7 years), 17 women with unilateral CTS (43±6 years), and 17 healthy women (43±6 years) were included in this study. Pressure pain thresholds (PPT) were bilaterally assessed over the median, ulnar, and radial nerve trunks, as well as over the C5-6 zygapophyseal joints, by an examiner blinded to the subjectsí condition. A mixed-model analysis of variance was used to evaluate differences in PPT among groups (LE, CTS, or controls) and between sides (affected/nonaffected or dominant/nondominant).

RESULTS

The individuals in both the LE and CTS groups demonstrated lower PPT bilaterally over the median (group, P<.001; side, P=.437), radial (group, P<.001; side, P=.556), and ulnar (group, P<.001; side, P=.938) nerve trunks as compared to controls. Additionally, radial (P<.001) and ulnar (P=.005) nerves were more sensitive bilaterally in patients with LE than in patients with CTS. The median nerve was more sensitive bilaterally in patients with CTS than patients with LE (P=.002). Lower PPT over the cervical spine (group, P<.001; side, P=.233) were found bilaterally in both the LE and CTS groups. Further, patients with CTS exhibited lower cervical PPT than patients with LE (P<.001). PPT was negatively correlated with both pain intensity and duration of symptoms in both the LE and CTS groups (P<.001).

CONCLUSIONS

Bilateral mechanical nerve pain hypersensitivity is related to specific and particular nerve trunks in women with either unilateral LE or CTS. Our results suggest the presence of central and peripheral sensitization mechanisms in individuals with either LE or CTS.

Median nerve small- and large-fiber damage in carpal tunnel syndrome: a quantitative sensory testing study

We explored the contribution of median nerve small (Aδ, C)-and large (Aβ)-fiber damage to the severity and topographic distribution of sensory symptoms in carpal tunnel syndrome (CTS) and the timing of fiber damage across CTS stages. We recruited 106 CTS patients. After selection, 49 patients were included. They underwent electrodiagnostic and quantitative sensory testing (QST) study and were asked on the severity of Boston Carpal Tunnel Questionnaire (BCTQ) Symptoms Severity Scale, daytime pain (DP), night pain and paresthesia, on the distribution of hand symptoms, and the presence of proximal symptoms. BCTQ Symptoms Severity Scale and DP severity was significantly correlated with Aδ-fiber damage. Small-fiber QST measures were impaired in electrodiagnostic-negative CTS patients and did not change across CTS neurographic stages. QST findings were not correlated to the topographical distribution of symptoms. Aδ-fiber damage contributes to CTS symptoms and in particular to DP. Night pain and paresthesia might be ascribed to ectopic fiber discharges secondary to median nerve enhanced mechanosensitivity. Small-fiber damage takes place earlier than large fiber. Median nerve fiber involvement does not directly contribute to extraterritorial symptoms spread. Our data may help understanding CTS pathophysiology and explain the well-known discrepancy between CTS symptoms and electrodiagnostic findings.

PERSPECTIVE

We explored the involvement of median nerve small and large fibers in carpal tunnel syndrome (CTS). We found a significant correlation between Aδ-fiber function and CTS symptoms. Small-fiber involvement took place in milder disease stages. These findings could help reconcile the discrepancy between CTS symptoms and electrodiagnostic data.

Revised definition of neuropathic pain and its grading system: an open case series illustrating its use in clinical practice

The definition of neuropathic pain has recently been revised by an expert committee of the Neuropathic Pain Special Interest Group of the International Association for the Study of Pain (NeuPSIG) as "pain arising as direct consequence of a lesion or disease affecting the somatosensory system," and a grading system of "definite," "probable," and "possible" neuropathic pain has been introduced. This open case series of 5 outpatients (3 men, 2 women; mean age 48 +/- 12 years) demonstrates how the grading system can be applied, in combination with appropriate confirmatory testing, to diagnosis neuropathic conditions in clinical practice. The proposed grading system includes a dynamic algorithm that enhances the physician's ability to determine with a greater level of certainty whether a pain condition is neuropathic. Its clinical use should be further validated in prospective studies.

EVIDENCE OF IMPROVEMENT IN DISTAL CONDUCTION OF ULNAR NERVE SENSORY FIBERS AFTER CARPAL TUNNEL RELEASE

OBJECTIVE

The aim of this study was to verify any effect of carpal tunnel release (CTR) on distal ulnar nerve conduction findings, using the database of a previous study performed to establish a protocol for CTR outcome.

METHODS

The motor and sensory ulnar distal conduction findings of 251 consecutive hands belonging to 217 patients (175 women and 42 men; mean age, 55.6 years) with idiopathic carpal tunnel syndrome (CTS) were reanalyzed before and 1 and 6 months after CTR.

RESULTS

Before surgery, 115 hands (45.8%) showed reduction of ulnar nerve sensory action potential (SAP) amplitude; this number was reduced significantly to 85 (33.9%) after CTR. The SAP amplitude and sensory conduction velocity values of the ulnar nerve showed significant improvement 1 month after CTR; SAP amplitude values showed further significant improvement 6 months after CTR. Patients' ages and occupations were independent predictors of reduced baseline SAP amplitudes of the ulnar nerve in CTS.

CONCLUSION

These results demonstrate an improvement in conduction values in sensory ulnar fibers in a percentage of patients with CTS after CTR, providing further support for the conclusion that in CTS ulnar fibers may be subject to compressive forces in the Guyon canal as a consequence of high pressure in the carpal tunnel.

Increased forward head posture and restricted cervical range of motion in patients with carpal tunnel syndrome

STUDY DESIGN

Case control study.

OBJECTIVES

To compare the amount of forward head posture (FHP) and cervical range of motion between patients with moderate carpal tunnel syndrome (CTS) and healthy controls. We also sought to assess the relationships among FHP, cervical range of motion, and clinical variables related to the intensity and temporal profile of pain due to CTS.

BACKGROUND

It is plausible that the cervical spine may be involved in patients with CTS. No studies have investigated the possible associations among FHP, cervical range of motion, and symptoms related to CTS.

METHODS

FHP and cervical range of motion were assessed in 25 women with CTS and 25 matched healthy women. Side-view pictures were taken in both relaxed-sitting and standing positions to measure the craniovertebral angle. A CROM device was used to assess cervical range of motion. Posture and mobility measurements were performed by an experienced therapist blinded to the subjects' condition. Differences in cervical range of motion were examined using the nonparametric Mann-Whitney U test. A 2-way mixed-model analysis of variance (ANOVA) was used to evaluate differences in FHP between groups and positions.

RESULTS

The ANOVA revealed significant differences between groups (F = 30.4; P<.001) and between positions (F = 6.5; P<.01) for FHP assessment. Patients with CTS had a smaller craniovertebral angle (greater FHP) than controls (P<.001) in both standing and sitting. Additionally, patients with CTS showed decreased cervical range of motion in all directions when compared to controls (P<.001). Only cervical flexion (rs = -0.43; P = .02) and lateral flexion contralateral to the side of the CTS (rs = -0.51; P = .01) were associated with the reported lowest pain experienced in the preceding week. A positive association between FHP and cervical range of motion was identified in both groups: the smaller the craniovertebral angle (reflective of a greater FHP), the smaller the range of motion (r values between 0.27 and 0.45; P<.05). Finally, cervical range of motion and FHP were negatively associated with age in the control group but not in the group with CTS.

CONCLUSIONS

Patients with mild/moderate CTS exhibited a greater FHP and less cervical range of motion, as compared to healthy controls. Additionally, a greater FHP was associated with a reduction in cervical range of motion. However, a cause-and-effect relationship cannot be inferred from this study. Future research should investigate if FHP and restricted cervical range of motion is a consequence or a causative factor of CTS and related symptoms (eg, pain).

Topographical assessment of symptom resolution following open carpal tunnel release

PURPOSE

Patients with carpal tunnel syndrome commonly present with paresthesias and pain extending into the small finger and proximal to the hand. This study was conducted to assess the ability of carpal tunnel release to relieve symptoms outside of the median nerve distribution.

METHODS

We enrolled 34 consecutive surgical patients (40 wrists) diagnosed exclusively with carpal tunnel syndrome based on the history, physical examination, and electrodiagnostic studies. Preoperative symptoms were categorized as pain, numbness, tingling, or "burning and electrical shocks." The presence or absence of each symptom type was recorded in 5 topographical areas (zone I, palmar thumb/index/long; zone II, small finger; zone III, volar forearm; zone IV, volar arm; and zone V, dorsal hand/forearm/arm). Patients were contacted at 4 to 6 weeks postoperatively to assess resolution of each symptom type by topographic zone.

RESULTS

Preoperatively, the cohort reported symptoms in all zones: zone I, 120 reports; zone II, 47 reports; zone III, 33 reports; zone IV, 7 reports; and zone V, 23 reports. Numbness (n = 40) and tingling (n = 38) were the most common symptoms, followed by pain (n = 29) and "burning/shocks" (n = 16). Postoperatively, the total number of reports within the 5 zones decreased from 230 to 20. The probability that surgery would eliminate patient symptoms was 88% (104 of 120) in zone I, 96% (45 of 47) in zone II, 97% (32 of 33) in zone III, 86% (6 of 7) in zone 4, and 100% (23 of 23) in zone V. Across zones, the overall probability of symptom resolution was as follows: pain > 80%, numbness/tingling > 85%, and "burning/shocks" > 90%.

CONCLUSIONS

Symptoms experienced outside of the median nerve distribution had a high likelihood of resolution after carpal tunnel release. Over 85% of symptoms in each of the anatomic zones studied resolved. Feelings of burning or shock-like sensations were most reliably relieved at early follow-up.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Ulnar nerve impairment at the wrist does not contribute to extramedian sensory symptoms in carpal tunnel syndrome

OBJECTIVE

Extramedian spread of sensory symptoms is frequent in carpal tunnel syndrome (CTS) but its mechanisms are unclear. We explored the possible role of subtle ulnar nerve abnormalities in the pathogenesis of extramedian symptoms.

METHODS

We recruited 350 CTS patients. After selection, 143 patients (225 hands) were included. The hand symptoms distribution was graded with a diagram into median (MED) and extramedian (EXTRAMED) pattern. We tested the correlation of ulnar nerve conduction measures with the distribution and the severity of symptoms involving the ulnar territory. The clinical significance of ulnar nerve conduction findings was explored with quantitative sensory testing (QST).

RESULTS

EXTRAMED distribution was found in 38.7% of hands. The ulnar neurographic measures were within normal values. Ulnar nerve sensory measures were significantly better in EXTRAMED vs MED hands and not significantly correlated to ulnar symptoms severity. Ulnar and median nerve sensory measures were significantly correlated. QST showed normal function of ulnar nerve alphabeta-fibers.

CONCLUSIONS

Ulnar nerve sensory abnormalities do not contribute to the spread of sensory symptoms into the ulnar territory.

SIGNIFICANCE

Our data favour the hypothesis that spinal and supraspinal neuroplastic changes may underlie extramedian spread of symptoms in CTS.

Pain and motor function in carpal tunnel syndrome: a clinical, neurophysiological and psychophysical study

OBJECTIVE

Patients with carpal tunnel syndrome (CTS) complain of motor symptoms. The study is aimed to understand which features are associated with the presence of motor symptoms in CTS.

METHODS

We recruited 282 consecutive CTS patients. After selection, 129 patients (203 hands) were included. Patients were asked about the presence and severity of hand weakness (HW) and hand clumsiness (HC). They underwent a self-administered questionnaire on symptoms, clinical evaluation and neurographic study. Quantitative sensory testing (QST) was performed on the patients with unilateral right CTS.

RESULTS

HW and HC may be found in 56 % and 48 % of CTS hands, respectively. HW was related to the severity of sensory symptoms (pain, numbness and tingling) but not to clinical-neurographic measures of median nerve involvement. HC was related to the severity of sensory symptoms and to the clinical-neurographic signs of motor but not sensory nerve damage. Motor symptoms were significantly more frequent in right hands. QST showed a relationship between the presence and severity of HW and HC and the warm threshold.

CONCLUSIONS

Motor symptoms may be found in approximately half of CTS hands. Clinical and neurographic signs of median nerve motor damage appear to be poorly correlated to motor symptoms. The factor that can help reconcile the discrepancy between motor symptoms and motor signs is pain. Pain modulation on motor function may take place at various anatomical levels in CTS. Nociceptive C-fibers may be involved in pain-motor interactions finally leading to motor symptoms.