Evaluation of Cold Sensitivity in Patients With Upper Extremity Nerve Compression Syndromes: A Scoping Review.

PURPOSE: The aim of this study was to review the literature to determine the prevalence of cold sensitivity in upper extremity nerve compression syndromes and the impact of treating nerve compression syndromes on cold sensitivity. METHODS: Following a standardized scoping review protocol, this study included interventional and observational study designs assessing patients with cold sensitivity and upper extremity nerve compression syndromes. Review articles, case reports, and small case series (n < 5) were excluded. The abstracts and eligible full texts were screened by 2 independent reviewers. Data were extracted and reported according to PRISMA extension for scoping reviews statement. RESULTS: Three databases were searched (Ovid MEDLINE, Ovid EMBASE, and CINAHL on EBSCO); 274 references were reviewed. Fifteen studies from the database search and 8 studies from the reference search were eligible for this review (n = 23). Two interventional and 21 observational studies were identified. The most common method for assessing cold sensitivity was cold pain threshold testing (n = 12), followed by subjective patient reporting (n = 4). The Cold Intolerance Symptom Severity questionnaire was the most common validated patient-reported outcome questionnaire used in the studies (n = 3). Cold sensitivity was most commonly reported in carpal tunnel syndrome (96% of the studies). The prevalence of cold sensitivity in nerve compression syndromes ranged from 20% to 69%. Nerve decompression improved the severity of cold sensitivity in 5 of 6 studies where cold sensitivity was studied. CONCLUSIONS: There is heterogenicity in the studies assessing cold sensitivity in nerve compression syndromes. Despite moderate prevalence in patients with carpal tunnel syndrome, cold sensitivity is understudied. Within the limitations of eligible studies reviewed, surgical decompression improved the severity of cold sensitivity in some studies. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Ontario wait times for delayed surgical treatment of traumatic peripheral nerve injury.

BACKGROUND: To better understand the occurrence and operative treatment of peripheral nerve injury (PNI) and the potential need for additional resources, it is essential to define the frequency and distribution of peripheral nerve procedures being performed. The objective of this study was to evaluate Ontario's wait times for delayed surgical treatment of traumatic PNI. METHODS: We retrieved data on wait times for peripheral nerve surgery from the Ontario Ministry of Health and Long-Term Care Wait Time Information System. We reviewed the wait times for delayed surgical treatment of traumatic PNI among adult patients (age ≥ 18 yr) from April 2009 to March 2018. Data collected included total cases, mean and median wait times, and demographic characteristics. RESULTS: Over the study period, 7313 delayed traumatic PNI operations were reported, with variability in the case volume distribution across Local Health Integration Networks (LHINs). The highest volume of procedures (2788) was performed in the Toronto Central LHIN, and the lowest volume (< 6) in the Waterloo Wellington and North Simcoe Muskoka LHINs. The population incidence of traumatic PNI requiring surgery was 5.1/10 000. The mean and median wait times from surgical decision to surgical repair were 45 and 27 days, respectively. Both the longest and shortest wait times occurred in LHINs with low case volumes. The provincial target wait time was met in 93% of cases, but women waited significantly longer than men (p < 0.001). CONCLUSION: The provincial distribution of traumatic PNI surgery was variable, and the highest volumes were in the LHINs with large populations. The provincial wait time strategy for traumatic PNI surgery is effective, but women waited longer than men. Precise reporting from all hospitals is necessary to accurately capture and understand the delivery of care after traumatic PNI.

Effect of Forearm Warming Compared to Hand Warming for Cold Intolerance Following Upper Extremity Trauma.

PURPOSE: This study evaluated the effect of forearm or hand warming versus bare hand conditions to improve cold-induced symptoms and skin temperatures in hand trauma patients. METHODS: Adults with symptoms of cold intolerance at least 3 months following hand trauma and age-/sex-matched controls were included. Testing sessions (bare hand, hand warming, forearm warming) were completed in a climate laboratory with continuous temperature monitoring. Outcomes included physical findings (skin temperature) and self-report symptoms (thermal comfort, pain). RESULTS: Eighteen participants (9 hand trauma patients, 9 control subjects) underwent testing. More severe cold intolerance was associated with higher Disabilities of the Arm, Shoulder, and Hand scores. With bare hands, skin temperatures changed significantly from baseline to cold exposure and to rewarming. Hand trauma patients had the lowest skin temperatures with cold exposure in the injured digits (14.3°C ± 3.5°C) compared with the contralateral uninjured (16.9°C ± 4.1°C) digits. Compared with bare hands, wearing gloves significantly increased the minimum temperature during cold exposure and the maximum temperature after rewarming. Patients reported higher pain with cold exposure. All participants reported significantly more comfort with less coldness with forearm and hand warming. CONCLUSIONS: There was cold response variability in hand trauma patients and control subjects. Hand trauma patients had greater changes in skin temperature during cold exposure that improved with glove warming. Continuous temperature monitoring identified subtle physiological changes associated with cold-induced pain and with warming interventions. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic III.

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.

A Case of Posterior Tibial Nerve Injury After Arthroscopic Calcaneoplasty.

We report the first case of distal posterior tibial nerve injury after arthroscopic calcaneoplasty. A 59-year-old male had undergone right arthroscopic calcaneoplasty to treat retrocalcaneal bursitis secondary to a Haglund's deformity. The patient complained of numbness in his right foot immediately after the procedure. Two years later and after numerous assessments and investigations, a lateral plantar nerve and medial calcaneal nerve lesion was diagnosed. In the operating room, the presence of an iatrogenic lesion to the distal right lateral plantar nerve (neuroma incontinuity involving 20% of the nerve) and the medial calcaneal nerve (complete avulsion) was confirmed. The tarsal tunnel was decompressed, and both the medial and the lateral plantar nerve were neurolyzed under magnification. To the best of our knowledge, our case report is the first to describe iatrogenic posterior tibial nerve injury after arthroscopic calcaneoplasty. It is significant because this complication can hopefully be avoided in the future with careful planning and creation of arthroscopic ports and treated appropriately with early referral to a nerve specialist if the patient's symptoms do not improve within 3 months.

Variations in procedure time based on surgery resident postgraduate year level.

BACKGROUND: With increasing scrutiny being placed on the allocation of health care dollars, data supporting the increased resources used to teach residents in the operating room (OR) are lacking. METHODS: All cases of patients undergoing laparoscopic cholecystectomies (LCs) and pancreaticoduodenectomies (PDs) from July 1, 2006 to July 1, 2011 were analyzed. Procedures were excluded based on the following: more than one resident listed in the operative report, with the exception of interns; LC requiring cholangiogram or conversion to an open procedure; or if a PD required additional procedures. Multiple linear regression was used to evaluate the association between procedure time and postgraduate year (PGY), adjusting for patient age and estimated blood loss. RESULTS: A total of 236 PDs and 357 LCs were included in the study. For LCs, after multiple linear regression, the association between procedure time and resident PGY was marginally significant (P = 0.0519) and suggested an inverse relationship; for every increase in resident PGY, there was a 2.66-min decrease in OR time. Based on our institution's figure of $18.13/min of OR time, the cost difference between PGYs 1 and 5 performing a LC would be $192.90 per case. For PDs, however, the association between procedure time and resident PGY was not significant. CONCLUSIONS: Junior residents likely prolong procedure times for more basic procedures such as LC but not for more complex procedures such as PD.

The Impact of COVID-19 on the Surgical Wait Times for Plastic and Reconstructive Surgery in Ontario.

Purpose: The aim of this study was to assess the impact of COVID-19 on surgical wait times for Plastic and Reconstructive Surgery (PRS) in Ontario, Canada. Methods: Ontario's wait time data has fourteen reporting categories for PRS. For each category, the mean wait time for consultation and for surgery were reported. Each category was given a priority ranging from 1 to 4. Two periods, three-month and six-month, were selected and compared to the same calendar months of the previous year. Wait times, surgical volume and percent change to the provincial wait time target were reported and compared to the baseline data. Results: This study reviewed 9563 consults and 15,000 operative cases. There was a 50% reduction in the volume of surgical consults during the study period compared to the baseline period (P = 0.004). The reduction ranged from 46% to 75% based on the reporting category. The volume of surgical cases decreased by 43% during the study period compared to the baseline period (P = 0.005). A statistically significant increase in the mean wait times for surgery was observed, involving priorities 2 to 4 (overall mean = 32 days, P ≤ 0.01). There was a 15% decrease in the percentage of surgeries meeting the provincial target times (P < 0.0001). Conclusion: COVID-19 has caused a significant reduction in the volume of cases performed in the majority of PRS categories with an overall increase in the wait times for consultation and for surgery. Recovery following COVID-19 will require strategies to address the growing volume of cases and wait times for surgery across all PRS categories.

Objectif: La présente étude vise à évaluer les effets de la COVID-19 sur les temps d'attente en vue de chirurgies plastiques et reconstructives (CPR) en Ontario, au Canada. Méthodologie: Les données sur les temps d'attente en Ontario comportent quatorze catégories de déclaration relatives aux CPR. Dans chaque catégorie, les chercheurs ont établi le temps d'attente moyen avant la consultation et l'opération et attribué à chaque catégorie une priorité de 1 à 4. Les chercheurs ont sélectionné deux périodes, de trois mois et de six mois, et les ont comparées aux mêmes mois civils de l'année précédente. Ils ont comparé le temps d'attente, le volume d'opérations et le pourcentage de changements avec les données de référence par rapport à la cible de temps d'attente ontarienne. Résultats: La présente étude portait sur 9 563 consultations et 15 000 opérations. Le nombre de consultations en chirurgie a baissé de 50% pendant la période de l'étude par rapport à la période de référence (p = 0.004). Cette baisse se situait entre 46% et 75%, en fonction de la catégorie de déclaration. Le nombre d'opérations a reculé de 43% par rapport à la période de référence (p = 0.005). Les chercheurs ont observé une augmentation statistiquement significative du temps d'attente moyen des opérations touchant les priorités 2 à 4 (moyenne globale = 32 jours, p ≤ 0.01). Le pourcentage d'opérations respectant les temps d'attente provinciaux a fléchi de 15% (p < 0.0001). Conclusion: La COVID-19 a suscité une importante réduction du nombre de cas dans la majorité des catégories de CPR et une augmentation globale des temps d'attente avant la consultation et l'opération. Des stratégies devront être mises en œuvre lors de la reprise qui suivra la COVID-19 pour tenir compte du nombre croissant de cas et des temps d'attente avant l'opération dans toutes les catégories de CPR.

Resilience is associated with cortical gray matter of the antinociceptive pathway in people with chronic pain.

Resilience is an important personal characteristic that influences health and recovery. Previous studies of chronic pain suggest that highly resilient people may be more effective at modulating their pain. Since brain gray matter in the antinociceptive pathway has also been shown to be abnormal in people with chronic pain, we examined whether resilience is related to gray matter in regions of interest (ROIs) of the antinociceptive pathway (rostral and subgenual anterior cingulate cortex (rACC, sgACC), anterior insula (aINS), dorsolateral prefrontal cortex (dlPFC)) normally and in people who are experiencing chronic pain. We extracted gray matter volume (GMV) and cortical thickness (CT) from 3T MRIs of 88 people with chronic pain (half males/females) and 86 healthy controls (HCs), who completed The Resilience Scale and Brief Pain Inventory. We found that resilience scores were significantly lower in people with chronic pain compared to HCs, whereas ROI GMV and CT were not different between groups. Resilience negatively correlated with average pain scores and positively correlated with GMV in the bilateral rACC, sgACC, and left dlPFC of people with chronic pain. Mediation analyses revealed that GMV in the right rACC and left sgACC partially co-mediated the relationship between resilience and average pain in people with chronic pain. The resilience-pain and some resilience-GMV relationships were sex-dependent. These findings suggest that the antinociceptive pathway may play a role in the impact of resilience on one's ability to modulate chronic pain. A better understanding of the brain-resilience relationship may help advance evidence-based approaches to pain management.

Radiation therapy for infiltrative giant cell tumor of the tendon sheath.

PURPOSE: Giant cell tumor of the tendon sheath (GCTTS) has a high recurrence after excision and can be a management challenge. Although experience with radiation therapy for GCTTS is limited, it is purported to control infiltrative cases and prevent recurrence. We describe our approach to primary and recurrent GCTTS, as well as our identification of infiltrative cases and their treatment with radiation therapy. METHODS: We reviewed 58 patients (32 men and 26 women) with GCTTS in the hand excised at 1 center between 1998 and 2009. Mean age at the time of excision at our center was 50 years. A total of 14 patients who had undergone primary excision at other centers were referred to our center with recurrent disease. Intraoperatively, we found infiltrative disease in 4 patients undergoing primary excision at our center and in 10 of the 14 patients referred to our institution with recurrent disease. All infiltrative (4 primary and 10 recurrent) cases were referred for radiation therapy. RESULTS: Of 14 patients with infiltrative tumors, 10 received radiation therapy (3 patients declined and 1 had a major comorbidity that precluded therapy). Radiation dose was either 35 Gy in 14 fractions or 48 Gy in 24 fractions. At 3.1 years' follow-up, none of the 10 patients treated with radiation therapy had recurrence. No long-term complications were associated with radiation therapy, and hand function was not adversely affected. We identified 4 recurrences, 2 of which were in patients with primary tumors without infiltrative features. Of the 4 patients who were referred for radiation but did not receive it, 2 patients developed recurrence by 2 years after referral. CONCLUSIONS: In cases of infiltrative GCTTS, radiation therapy may provide local tumor control with preservation of hand function. Radiation therapy may be particularly helpful when further surgery is not a good option. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Carpal tunnel surgery dampens thalamocortical and normalizes corticocortical functional connectivity.

Carpal tunnel syndrome is the most common entrapment neuropathy and is associated with altered brain function and structure. However, little is understood of the central mechanisms associated with its pain, symptom presentation, and treatment-related resolution. This longitudinal study evaluated carpal tunnel syndrome-related alterations in brain network communication and relationships to behavioural signs of central sensitization before and after carpal tunnel release surgery. We tested the hypothesis that carpal tunnel syndrome is associated with condition- and treatment-related plasticity in brain regions involved in somatosensation. We used quantitative sensory testing and clinical and pain questionnaires to assess sensory and pain function in 25 patients with carpal tunnel syndrome before (18 women, 7 men) and after (n = 16) surgery, and 25 sex- and age-matched healthy controls. We also acquired resting-state functional MRI to determine functional connectivity of two key nodes in the somatosensory system, the thalamus and primary somatosensory cortex. Seed-to-whole brain resting-state static functional connectivity analyses revealed abnormally low functional connectivity for the hand area of the primary somatosensory cortex with the contralateral somatosensory association cortex (supramarginal gyrus) before surgery (P < 0.01). After clinically effective surgery: (i) Primary somatosensory functional connectivity was normalized with the contralateral somatosensory association cortex and reduced with the dorsolateral prefrontal cortex (a region associated with cognitive and emotional modulation of pain) and primary visual areas (P < 0.001) from pre-op levels; and (ii) Functional connectivity of the thalamus with the primary somatosensory and motor cortices was attenuated from pre-op levels (P < 0.001) but did not correlate with temporal summation of pain (a behavioural measure of central sensitization) or clinical measures. This study is the first to reveal treatment-related neuroplasticity in resting-state functional connectivity of the somatosensory system in carpal tunnel syndrome. The findings of dysfunctional resting-state functional connectivity point to aberrant neural synchrony between the brain's representation of the hand with regions involved in processing and integrating tactile and nociceptive stimuli and proprioception in carpal tunnel syndrome. Aberrant neural communication between the primary somatosensory hand area and the dorsolateral prefrontal cortex could reflect increased attention to pain, paraesthesia, and altered sensation in the hand. Finally, reduced thalamocortical functional connectivity after surgery may reflect central plasticity in response to the resolution of abnormal sensory signals from the periphery. Our findings support the concept of underlying brain contributions to this peripheral neuropathy, specifically aberrant thalamocortical and corticocortical communication, and point to potential central therapeutic targets to complement peripheral treatments.

Peripheral Nerve Focused Ultrasound Lesioning-Visualization and Assessment Using Diffusion Weighted Imaging.

Objectives: Magnetic resonance-guided focused ultrasound (MRgFUS) is a non-invasive targeted tissue ablation technique that can be applied to the nervous system. Diffusion weighted imaging (DWI) can visualize and evaluate nervous system microstructure. Tractography algorithms can reconstruct fiber bundles which can be used for treatment navigation and diffusion tensor imaging (DTI) metrics permit the quantitative assessment of nerve microstructure in vivo. There is a need for imaging tools to aid in the visualization and quantitative assessment of treatment-related nerve changes in MRgFUS. We present a method of peripheral nerve tract reconstruction and use DTI metrics to evaluate the MRgFUS treatment effect. Materials and Methods: MRgFUS was applied bilaterally to the sciatic nerves in 6 piglets (12 nerves total). T1-weighted and diffusion images were acquired before and after treatment. Tensor-based and constrained spherical deconvolution (CSD) tractography algorithms were used to reconstruct the nerves. DTI metrics of fractional anisotropy (FA), and mean (MD), axial (AD), and radial diffusivities (RD) were measured to assess acute (<1-2 h) treatment effects. Temperature was measured in vivo via MR thermometry. Histological data was collected for lesion assessment. Results: The sciatic nerves were successfully reconstructed in all subjects. Tract disruption was observed after treatment using both CSD and tensor models. DTI metrics in the targeted nerve segments showed significantly decreased FA and increased MD, AD, and RD. Transducer output power was positively correlated with lesion volume and temperature and negatively correlated with MD, AD, and RD. No correlations were observed between FA and other measured parameters. Conclusions: DWI and tractography are effective tools for visualizing peripheral nerve segments for targeting in non-invasive surgical methods and for assessing the microstructural changes that occur following MRgFUS treatment.

Sex-Specific Abnormalities and Treatment-Related Plasticity of Subgenual Anterior Cingulate Cortex Functional Connectivity in Chronic Pain.

The subgenual anterior cingulate cortex (sgACC) is a key node of the descending antinociceptive system with sex differences in its functional connectivity (FC). We previously reported that, in a male-prevalent chronic pain condition, sgACC FC is abnormal in women but not in men. This raises the possibility that, within a sex, sgACC FC may be either protective or represent a vulnerability to develop a sex-dominant chronic pain condition. The aim of this study was to characterize sgACC FC in a female-dominant chronic pain condition, carpal tunnel syndrome (CTS), to investigate whether sgACC abnormalities are a common feature in women with chronic pain or unique to individuals with pain conditions that are more prevalent in the opposite sex. We used fMRI to determine the resting state FC of the sgACC in healthy controls (HCs, n = 25, 18 women; 7 men) and people with CTS before (n = 25, 18 women; 7 men) and after (n = 17, 13 women; 4 men) successful surgical treatment. We found reduced sgACC FC with the medial pre-frontal cortex (mPFC) and temporal lobe in CTS compared with HCs. The group-level sgACC-mPFC FC abnormality was driven by men with CTS, while women with CTS did not have sgACC FC abnormalities compared with healthy women. We also found that age and sex influenced sgACC FC in both CTS and HCs, with women showing greater FC with bilateral frontal poles and men showing greater FC with the parietal operculum. After surgery, there was reduced sgACC FC with the orbitofrontal cortex, striatum, and premotor areas and increased FC with the posterior insula and precuneus compared with pre-op scans. Abnormally reduced sgACC-mPFC FC in men but not women with a female-prevalent chronic pain condition suggests pain-related sgACC abnormalities may not be specific to women but rather to individuals who develop chronic pain conditions that are more dominant in the opposite sex. Our data suggest the sgACC plays a role in chronic pain in a sex-specific manner, and its communication with other regions of the dynamic pain connectome undergoes plasticity following pain-relieving treatment, supporting it as a potential therapeutic target for neuromodulation in chronic pain.

Reversal of cortical reorganization in human primary motor cortex following thumb reconstruction.

Deafferentation such as the amputation of a body part causes cortical reorganization in the primary motor cortex (M1). We investigated whether this reorganization is reversible after reconstruction of the lost body part. We tested two patients who had long-standing thumb amputations followed by thumb reconstruction with toe-to-thumb transfer 9 to 10 mo later and one patient who underwent thumb replantation immediately following traumatic amputation. Using transcranial magnetic stimulation, we measured the motor evoked potential (MEP) threshold, latency, short-interval intracortical inhibition (SICI), and intracortical facilitation (ICF) at different time points in the course of recovery in abductor pollicis brevis muscle. For the two patients who underwent late toe-to-thumb transfer, the rest motor threshold was lower on the injured side than that on the intact side before surgery and it increased with time after reconstruction, whereas the active motor threshold remained unchanged. The rest and active MEP latencies were similar on the injured side before and < or =15 wk after surgery and followed by restoration of expected latency differences. SICI was reduced before surgery and progressively normalized with the time after surgery. ICF did not change with time. These physiological measures correlated with the recovery of motor and sensory functions. All the measurements on the intact side of the toe-to-thumb transfer patients and in the patient with thumb replantation immediately following traumatic amputation remained stable over time. We conclude that chronic reorganization occurring in the M1 after amputation can be reversed by reconstruction of the lost body part.

Cutting your nerve changes your brain.

Following upper limb peripheral nerve transection and surgical repair, some patients regain good sensorimotor function while others do not. Understanding peripheral and central mechanisms that contribute to recovery may facilitate the development of new therapeutic interventions. Plasticity following peripheral nerve transection has been demonstrated throughout the neuroaxis in animal models of nerve injury. However, the brain changes that occur following peripheral nerve transection and surgical repair in humans have not been examined. Furthermore, the extent to which peripheral nerve regeneration influences functional and structural brain changes has not been characterized. Therefore, we asked whether functional changes are accompanied by grey and/or white matter structural changes and whether these changes relate to sensory recovery? To address these key issues we (i) assessed peripheral nerve regeneration; (ii) measured functional magnetic resonance imaging brain activation (blood oxygen level dependent signal; BOLD) in response to a vibrotactile stimulus; (iii) examined grey and white matter structural brain plasticity; and (iv) correlated sensory recovery measures with grey matter changes in peripheral nerve transection and surgical repair patients. Compared to each patient's healthy contralesional nerve, transected nerves have impaired nerve conduction 1.5 years after transection and repair, conducting with decreased amplitude and increased latency. Compared to healthy controls, peripheral nerve transection and surgical repair patients had altered blood oxygen level dependent signal activity in the contralesional primary and secondary somatosensory cortices, and in a set of brain areas known as the 'task positive network'. In addition, grey matter reductions were identified in several brain areas, including the contralesional primary and secondary somatosensory cortices, in the same areas where blood oxygen level dependent signal reductions were identified. Furthermore, grey matter thinning in the post-central gyrus was negatively correlated with measures of sensory recovery (mechanical and vibration detection) demonstrating a clear link between function and structure. Finally, we identified reduced white matter fractional anisotropy in the right insula in a region that also demonstrated reduced grey matter. These results provide insight into brain plasticity and structure-function-behavioural relationships following nerve injury and have important therapeutic implications.

Relationships among pain disability, pain intensity, illness intrusiveness, and upper extremity disability in patients with traumatic peripheral nerve injury.

PURPOSE: In patients with a peripheral nerve injury, a simple conceptualization assumes that pain disability is determined by pain intensity. This study evaluated the relationships among pain intensity, illness intrusiveness, and pain disability. METHODS: After we obtained ethics board approval, we enrolled English-speaking adult patients who had experienced an upper extremity peripheral nerve injury 0.5 to 15 years previously. Patients completed the Disabilities of the Arm, Shoulder, and Hand (DASH), Illness Intrusiveness Scale, Pain Disability Index, and McGill Pain questionnaires. We used multivariate linear regression to evaluate the variables that predicted pain disability. RESULTS: There were 124 patients (41 women, 83 men; mean ± SD, 41 ± 16 y of age). The median time since injury was 14 months (range, 6-145 months), and there were 43 brachial plexus nerve injuries. Mean ± SD scores were: pain disability, 29 ± 18; illness intrusiveness, 40 ± 18; DASH, 45 ± 22; and pain intensity, 4.6 ± 3.0. The pain disability, DASH, and illness intrusiveness scores were significantly higher in patients with brachial plexus injuries than in those with distal nerve injuries (p<.05). There was strong correlation between pain disability and DASH (r = 0.764, p<.001) and illness intrusiveness (r = 0.738, p<.001) and a weaker correlation with pain intensity (r = 0.549, p<.001). The final regression model predicting pain disability scores explained 70% of the variance with these predictors: DASH (ß = 0.452, p<.001), illness intrusiveness (ß = 0.372, p<.001), and pain intensity (ß = 0.143, p=.018). CONCLUSIONS: Pain disability was substantial after nerve injury, and pain intensity explained the least variance among the model variables. Pain intensity should be considered only one component of pain, and the impact of pain in the context of disability should be considered in patients with chronic nerve injury. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

Patient-reported outcome after peripheral nerve injury.

PURPOSE: This study evaluated patient-reported outcome and the factors associated with disability after an upper extremity nerve injury. We hypothesized that patients at least 6 months after injury would report considerable disability and that pain would be the strongest predictor of the Disabilities of the Arm, Shoulder, and Hand (DASH) score. METHODS: After research ethics board approval, the medical charts of patients with these inclusion criteria were reviewed: adults; presenting to a nerve surgeon; 6 months or greater after nerve injury. Patients completed the DASH questionnaire and the Short Form-36 (SF-36) as a routine part of the initial evaluation. These data were reviewed retrospectively to determine predictors of the DASH score. RESULTS: There were 84 patients (mean age, 39 years; SD, 14 years) with brachial plexus (n=27) and peripheral nerve (n=57) injuries. The mean time after injury was 38 months (SD, 47). For all SF-36 domains, the mean values of the nerve-injured patients were significantly lower than the normative data, indicating a lower health status. The mean DASH score was 52 (SD, 22) of 100. Significantly more disability was associated with more SF-36 bodily pain and with brachial plexus injuries. In the final regression model, SF-36 bodily pain, age, and nerve injured were significant predictors of the DASH score. SF-36 bodily pain accounted for 35% of the variance. CONCLUSIONS: Substantial long-term disability (high DASH scores) was found in patients after nerve injury that was predicted by higher pain, older age, and brachial plexus injury. Further investigation of this pain and the associated factors may provide the opportunity for improved health-related quality of life. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic II.

Factor Structure of the Disabilities of the Arm, Shoulder and Hand Questionnaire in Upper Extremity Nerve Injury.

BACKGROUND: This study evaluated the validity of the factor structure of the Disabilities of the Arm, Shoulder and Hand questionnaire to assess upper extremity disability in patients with upper extremity nerve injury. METHODS: Data were used from previous cross-sectional studies of patients with upper extremity nerve injuries. Research ethics approval was obtained for secondary data analyses. Descriptive and factor analyses were performed. RESULTS: Patients (n = 242; 170 men and 72 women) with upper extremity nerve injury included distal nerve (n = 131), brachial plexus (n = 88), and single proximal shoulder nerve (n = 23). The mean Disabilities of the Arm, Shoulder and Hand questionnaire score was 47.3 ± 22. For the questionnaire, a three-factor structure had the highest variance and no overlap between factors. The factors related to (1) light effort tasks, (2) greater effort tasks, and (3) work/social activity limitations and pain. Brachial plexus injuries had significantly higher overall questionnaire scores compared to distal and single proximal nerve injuries. The light effort factor scores were significantly lower in single proximal nerve injuries compared with brachial plexus and distal nerve injuries. Nondominant compared to dominant hand involvement revealed no difference in overall questionnaire scores but significantly higher dominant hand scores in the light effort factor (p = 0.001). CONCLUSIONS: In patients with nerve injury, the factor analysis of the Disabilities of the Arm, Shoulder and Hand questionnaire indicated a multifactor construct. These domains should be considered when using the questionnaire and may be helpful to assess disability related to specific tasks in different nerve injuries and with dominant hand involvement.

Cortical plasticity following nerve transfer in the upper extremity.

With increasing clinical experience, peripheral nerve surgeons have come to appreciate the important role that cortical plasticity and motor relearning play in functional recovery following a nerve transfer. Neurostimulation (transcranial magnetic stimulation), and neuroimaging (functional MRI, structural MRI, magnetoencephalography) measure different aspects of cortical physiology and when used together are powerful tools in the study of cortical plasticity. The mechanisms of cortical plasticity, according to current and widely accepted opinions, involve the unmasking of previously ineffective connections or the sprouting of intact afferents from adjacent cortical or subcortical territories. Although significant strides have been made in our understanding of cortical plasticity following nerve transfer and during motor relearning, a great deal remains that we do not understand. Cortical plasticity and its manipulation may one day become important contributors to improve functional outcome following nerve transfer.