Silvia Marani

Extra-median spread of sensory symptoms in carpal tunnel syndrome suggests the presence of pain-related mechanisms.

Abstract Patients with carpal tunnel syndrome (CTS) may complain of sensory symptoms outside the typical median nerve distribution. The study is aimed to understand which clinical features are associated with the extra‐median distribution of symptoms in CTS. We recruited 241 consecutive CTS patients. After selection, 103 patients (165 hands) were included. The symptoms distribution was evaluated with a self‐administered hand symptoms diagram. Patients underwent objective evaluation, neurographic study and a self‐administered questionnaire on subjective complaints. No clinical or electrodiagnostic signs of ulnar nerve involvement were found in the 165 hands. Median distribution of symptoms was found in 60.6% of hands, glove distribution in 35.2% and ulnar distribution in 4.2%. Objective measures of median nerve lesion (tactile hypaesthesia and thenar muscles hypasthenia) and neurographic involvement were significantly more severe in median hands than in the other groups. Subjective complaints (nocturnal pain, numbness and tingling sensations) were significantly more severe in glove hands. Neurophysiological and objective measures were not correlated with subjective complaints. The severity of the objective examination and neurographic involvement and the intensity of sensory complaints appear to be independent factors that influence the symptoms distribution. Extra‐median spread of sensory symptoms was associated with higher levels of pain and paresthesia. We suggest that central nervous system mechanisms of plasticity may underlie the spread of symptoms in CTS.

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

Abstract  Patients with carpal tunnel syndrome (CTS) usually complain of pain and paresthesia in the hand or wrist, but pain proximally to the wrist has been frequently reported in this condition. This study was aimed at understanding which clinical features are associated with the presence of proximal pain (PP) in the upper limb of CTS patients. We recruited 250 patients with clinical and neurophysiological evidence of CTS. After thorough selection to rule out concomitant upper limb painful conditions, 112 patients (175 hands) were included. PP was defined as the presence of pain in the upper limb proximally to the wrist (neck excluded) in association with sensory complaints in the hand. Patients were asked about the presence and severity of proximal sensory complaints, the distribution of sensory complaints in the hand, and underwent an objective evaluation and neurographic study. Thenar muscle strength was significantly larger, the neurophysiological measures were significantly less severe, and hand paresthesia was significantly greater in patients with PP. The neurographic score and the measures of median nerve damage were inversely correlated with the severity of PP. PP was related to extramedian spread of symptoms in the hand. None of the objective/neurographic variables was related to severity of sensory complaints restricted to the hand. PP may be found in a consistent number of CTS patients. PP may represent a clinical marker of mild median nerve damage. The presence of proximal complaints might be related to peripheral or central nervous system mechanisms.

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

ObjectivePatients 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.MethodsWe 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.ResultsHW 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.ConclusionsMotor 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.

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.

132 ULNAR NERVE IMPAIRMENT AT THE WRIST IS NOT CORRELATED WITH EXTRAMEDIAN SPREAD OF SENSORY SYMPTOMS IN CARPAL TUNNEL SYNDROME

Background & Aims: Pain is the most prominent but least well-studied feature of osteoarthritis (OA). Retrograde labelling of neurons innervating the OA joint decreases 40% at 31 days of disease progression, with the total number of DRG cells remaining unaltered, but increasing the number of medium-large cells. Therefore, we hypothesized that neuronal damage might be occurring during OA, and to test this hypothesis we evaluated the expression of ATF-3 and NPY (known to be increased by neuronal damage) in DRG neurons. Since ATF-3 has also been associated with the regeneration of injured cells, we also evaluated its colocalization with the regeneration marker GAP-43. Methods: All procedures were performed according to the ethical guidelines for the study of experimental pain in conscious animals. OA was induced by injection of 2mg of mono-iodoacetate in the knee joint of adult Wistar rats. Animals were sacrificed at 3, 7 and 14 days post-injection. L3-L5 DRGs were used for immunohistochemistry for NPY, ATF-3 and GAP-43. Results: An increase in the number of ATF-3-positive cells was observed 3 days after the induction of OA. Such increase diminished over time, but the percentage of ATF-3 cells positive for GAP43 increased at days 7 and 14. NPY expression showed a similar pattern as ATF-3 expression. Conclusion: The increased ATF-3 and NPY expression suggests that damage in DRG neurons innervating the OA joint may be occurring. The increased co-localization of ATF-3 and GAP-43 over time indicates that neuronal regeneration may be taking place as a response to neuronal damage.

215 EXTRAMEDIAN AND PROXIMAL SPREAD OF SENSORY SYMPTOMS IN CARPAL TUNNEL SYNDROME: A CLINICAL—NEUROPHYSIOLOGICAL STUDY

Background and aims. The early presence of cold and mechanical hyperalgesia, sympathetic nervous system dysfunction and moderate pain and disability are predictive of poor outcome following whiplash. As this condition is often managed in primary care it is important that these features are easily detected. The aims were: (1) determine neuropathic pain components of acute whiplash, (2) investigate the relationship of S-LANSS scores to sensory features of acute whiplash, and (3) determine relationships of S-LANSS scores and pain and disability levels. Methods. Participants (85) with acute (<3 weeks) whiplash (WAD II) participated. The S-LANSS and NDI were completed. Measures included: cold and pressure pain thresholds at both local (cervical) and remote sites; sympathetic vasoconstrictor responses (SVR); brachial plexus provocation test (BPPT). Participants were classified into 2 groups (S-LANSS: P12 neuropathic; <12 non-neuropathic). Group differences were analyzed using ANOVA. Stepwise regression analyses were performed to predict S-LANSS and NDI scores p < 0.05. Results. 30% of participants demonstrated a neuropathic component (S-LANSS P12). This group showed higher pain and disability (NDI), cold hyperalgesia and heightened responses to the BPPT (all p < 0.015). Item 4 (pain in bursts predicted cold hyperalgesia) and items 4, 5 (burning pain) and 7 (pain with pressure) predicted NDI scores (r = 32%, p = 0.04). Conclusions. A predominant neuropathic pain component is prevalent in acute whiplash and is related to a more complex presentation of higher pain and disability and hypersensitivity. The S-LANSS may be a useful tool in the early assessment of whiplash, particularly in primary care practice.