The controversy of the normal values of ultrasonography in carpal tunnel syndrome: diagnostic accuracy of wrist-dependent CSA revisited.

INTRODUCTION: No consensus exists about the upper limit of normal (ULN) of the cross-sectional area (CSA) of the median nerve in diagnosing carpal tunnel syndrome (CTS). Previously, we demonstrated a strong positive correlation between wrist circumference and CSA. ULN depending on wrist circumference turned out to have a low sensitivity, which was hypothesized to be caused by an age mismatch. The aim of this study was to re-evaluate the found invariance by augmentation of the healthy control group, adding older subjects, and to determine the diagnostic accuracy of the updated normal values. METHODS: CSA and wrist circumference were measured in an additional 42 healthy controls in the ages of 40-60. Univariable and multivariable linear regression analyses were applied to determine predicting factors for CSA. Diagnostic accuracy was assessed in a prospective cohort of 253 patients. RESULTS: A strong correlation was found between wrist circumference and CSA (r = 0.61). Wrist circumference is the most important independent predictor for ULN (r2 = 0.37). We managed to simplify our newly derived regression equations, which turned out to be unrelated to age. Sensitivity of our new equations is low, but higher than a general fixed cut-off value (53.4% and 47.4%, respectively). DISCUSSION: Wrist circumference is the most important independent predicting factor of CSA. By using our updated equations and taking wrist circumference into account, one can determine a more precise ULN for each individual, which will lead to the improvement of the diagnostic accuracy of ultrasonography (US). Sensitivity for US in diagnosing CTS remains low and it can therefore not replace EDX.

Outcome after carpal tunnel release: effects of learning curve.

INTRODUCTION: In carpal tunnel release, it is yet unclear whether a learning curve exists among surgeons. The aim of our study was to investigate if outcome after carpal tunnel release is dependent on surgeon's experience and to get an impression of the learning curve for this procedure. METHODS: A total of 188 CTS patients underwent carpal tunnel release. Patients completed the Boston Carpal Tunnel Questionnaire at baseline and 6-8 months postoperatively together with a six-point scale for perceived improvement. RESULTS: Patients operated by an experienced resident or certified surgeon reported a favorable outcome more often than patients operated by an inexperienced resident (adjusted OR 3.23 and adjusted OR 3.16, respectively). In addition, a negative association was found between surgeon's years of experience and postoperative Symptom Severity Scale and Functional Status Scale scores. DISCUSSION: Outcome after carpal tunnel release seems to be dependent on surgical experience, and there is a learning curve in residents.

Long-term outcome after carpal tunnel release and identification of prognostic factors.

BACKGROUND: The effectiveness of the surgical treatment of carpal tunnel syndrome (CTS) is well known on short term. However, limited data is available about long-term outcome after carpal tunnel release (CTR). The aims of this study were to explore the long-term outcome after CTR and to identify prognostic factors for long-term outcome. METHODS: Patients with clinically defined CTS underwent CTR and completed the Boston Carpal Tunnel Questionnaire at baseline (T0), at about 8 months (T1), and after a median follow-up of 9 years (T2), as well as a 6-point scale for perceived improvement (at T1 and T2). Potentially prognostic factors were identified by logistic regression analysis and correlation. RESULTS: At long-term follow-up, 87 patients (40.3%) completed the questionnaires. Mean score on Symptom Severity Scale (2.87 to 1.54; p < 0.001) and Functional Status Scale (2.14 to 1.51; p < 0.001) improved at 8 months and did not change significantly after 8 months. A favorable outcome was reported in 81.6%. A good treatment outcome after 8 months and to a lesser extent a lower FSS score at T0 were associated with a better long-term outcome. CONCLUSIONS: CTR is a robust treatment for CTS and its effect persists after a period of 9 years. The most important factor associated with long-term outcome is treatment outcome after about 8 months and to a lesser extent functional complaints preoperatively. Outcome is independent of patient characteristics, electrodiagnostic test results, or findings at the initial neurological examination.

Syndrome of transient headache and neurological deficits with cerebrospinal fluid lymphocytosis (HaNDL): A case report with serial electroencephalography (EEG) recordings.. Is there an association with human herpes virus type 7 (HHV-7) infection?

Introduction The syndrome of transient headache and neurological deficits with cerebrospinal fluid lymphocytosis (HaNDL) is a diagnosis made by exclusion. In the literature, different etiological explanations are proposed for HaNDL, including an immune-mediated reaction after a viral infection. Case description We present a case of a 23-year-old woman with several episodes of transient headache, neurological deficits and cerebrospinal fluid lymphocytosis. All diagnostic criteria for the HaNDL syndrome were fulfilled; however, additional cerebrospinal fluid analysis showed a positive polymerase chain reaction (PCR) for human herpes virus type 7 (HHV-7). Discussion The possible role of a (prodromal) viral infection in the etiology of HaNDL is discussed. Also the role of electroencephalography (EEG) recordings is discussed. Serial EEG recordings showed generalized slowing, frontal intermittent rhythmic delta activity (FIRDA) and symmetric triphasic frontal waves with a dilation lag.

Ultrasound of the cervical roots and brachial plexus in neonates.

INTRODUCTION: In this exploratory study we investigated whether ultrasound can visualize the neonatal cervical roots and brachial plexus. METHODS: In 12 healthy neonates <2 days old, the neck region was studied unilaterally with ultrasound using a small-footprint 15-7-MHz transducer. RESULTS: The C5-C8 nerve roots and brachial plexus could be imaged with sufficient delineation of the root exits to assess their integrity. The brachial plexus was more difficult to discern from the surrounding area in neonates compared with adults, especially in the interscalene region because of the smaller amount of connective tissue in and surrounding muscles and nerves. In addition, the large deposits of brown fat make for a different ultrasound appearance of the neonatal neck compared with adults. CONCLUSIONS: Ultrasound of the neonatal cervical nerve roots is feasible and may be used as a non-invasive screening technique to assess nerve root integrity in obstetric brachial plexus injury.

Bifid median nerve in carpal tunnel syndrome: do we need to know?

INTRODUCTION: We tested the hypothesis that a bifid median nerve predisposes to development of carpal tunnel syndrome (CTS) and investigated differences in electrophysiological findings and outcome. METHODS: A total of 259 consecutive patients with clinically defined CTS were included and investigated clinically, electrophysiologically, and ultrasonographically. Fifty-four healthy asymptomatic volunteers were investigated ultrasonographically. RESULTS: The prevalence of bifid median nerves is equal in patients with CTS and controls. Electrophysiological and ultrasonographic abnormalities are more pronounced in patients with non-bifid median nerves. Some outcome data are better in patients with non-bifid median nerves, but others do not show significant differences. CONCLUSIONS: A bifid median nerve is not an independent risk factor for development of CTS. Some of our data suggest outcome after surgical decompression to be different, but others do not. The surgical technique in these patients may therefore have to be reevaluated.

The necessity of electrodiagnostic studies and ultrasound in ulnar nerve entrapment according to surgeons in the Netherlands.

BACKGROUND: Ulnar nerve entrapment at the elbow (UNE) is the second most prevalent entrapment neuropathy after carpal tunnel syndrome. The objective of this study was to evaluate the expert opinion of different surgical disciplines regarding the need for electrodiagnostic or ultrasound confirmation of UNE and, if so, which test was preferred for confirmation. METHODS: A questionnaire was sent to all neurosurgeons and plastic or hand surgeons in the Netherlands to evaluate the current practice in planning surgical treatment of UNE. RESULTS: The response rate was 36.4 % (134 out of 368). 94 % of surgeons reported that > 95 % of their patients had EDX or ultrasound studies before surgery. 80.6 % of all surgeons who responded reported that they seldom operated on UNE without electrodiagnostic confirmation. Hand surgeons (25.9 %) were more willing to operate on clinically diagnosed UNE without EDX than neurosurgeons (9.4 %) CONCLUSIONS: Dutch surgeons prefer diagnostic confirmation of UNE either by ultrasound or EDX, with a preference for EDX and the vast majority of operated patients do have either EDX or ultrasound or both before surgery. Compared to neurosurgeons, hand surgeons are more willing to operate on patients with clinically defined UNE but normal electrodiagnostic studies.

Ultrasonography in severe carpal tunnel syndrome.

INTRODUCTION: In up to 30% of patients with carpal tunnel syndrome (CTS), the cross-sectional area (CSA) of the median nerve may not be enlarged. We hypothesize that this could be the result of secondary atrophy of the nerve in severe CTS. The aim of this study was to measure the ultrasonographic CSA of the median nerve at the wrist in patients with severe CTS. METHODS: In 14 consecutive patients with clinically and electrophysiologically defined severe CTS, the CSA of the median nerve was measured and compared with that of control subjects. RESULTS: CSA of the median nerve exceeded the upper limit of normal in the majority of patients with severe CTS. CONCLUSIONS: Atrophy of the median nerve in severe CTS does not explain negative ultrasonographic test results. Instead, the CSA of the median nerve is enlarged in most patients with severe CTS.

A novel seven-octapeptide repeat insertion in the prion protein gene (PRNP) in a Dutch pedigree with Gerstmann-Sträussler-Scheinker disease phenotype: comparison with similar cases from the literature.

Human prion diseases can be sporadic, inherited or acquired by infection and show considerable phenotypic heterogeneity. We describe the clinical, histopathological and pathological prion protein (PrP(Sc)) characteristics of a Dutch family with a novel 7-octapeptide repeat insertion (7-OPRI) in PRNP, the gene encoding the prion protein (PrP). Clinical features were available in four, neuropathological features in three and biochemical characteristics in two members of this family. The clinical phenotype was characterized by slowly progressive cognitive decline, personality change, lethargy, depression with anxiety and panic attacks, apraxia and a hypokinetic-rigid syndrome. Neuropathological findings consisted of numerous multi- and unicentric amyloid plaques throughout the cerebrum and cerebellum with varying degrees of spongiform degeneration. Genetic and molecular studies were performed in two male family members. One of them was homozygous for valine and the other heterozygous for methionine and valine at codon 129 of PRNP. Sequence analysis identified a novel 168 bp insertion [R2-R2-R2-R2-R3g-R2-R2] in the octapeptide repeat region of PRNP. Both patients carried the mutation on the allele with valine at codon 129. Western blot analysis showed type 1 PrP(Sc) in both patients and detected a smaller ~8 kDa PrP(Sc) fragment in the cerebellum in one patient. The features of this Dutch kindred define an unusual neuropathological phenotype and a novel PRNP haplotype among the previously documented 7-OPRI mutations, further expanding the spectrum of genotype-phenotype correlations in inherited prion diseases.

Guillain-Barré syndrome subtypes related to Campylobacter infection.

BACKGROUND: In Guillain-Barré syndrome (GBS), the diversity in electrophysiological subtypes is unexplained but may be determined by geographical factors and preceding infections. Acute motor axonal neuropathy (AMAN) is a frequent GBS variant in Japan and one study proposed that in Japan, Campylobacter jejuni infections exclusively elicit AMAN. In The Netherlands C jejuni is the predominant type of preceding infection yet AMAN is rare. This may indicate that not all Dutch GBS patients with C jejuni infections have AMAN. OBJECTIVE: To determine if GBS patients with a preceding C jejuni infection in The Netherlands exclusively have AMAN. METHODS: Retrospective analysis of preceding infections in relation to serial electrophysiology and clinical data from 123 GBS patients. C jejuni related cases were defined as having preceding diarrhoea and positive C jejuni serology. Electrophysiological characteristics in C jejuni related cases were compared with those in viral related GBS patients. In addition, eight GBS patients from another cohort with positive stool cultures for C jejuni were analysed. RESULTS: 17 (14%) of 123 patients had C jejuni related GBS. C jejuni patients had lower motor and higher sensory action potentials compared with viral related cases. Nine (53%) C jejuni patients had either AMAN or inexcitable nerves. However, three (18%) patients fulfilled the criteria for acute inflammatory demyelinating polyneuropathy (AIDP). Also, two (25%) of eight additional patients with a C jejuni positive stool sample had AIDP. CONCLUSION: In The Netherlands, C jejuni infections are strongly, but not exclusively, associated with axonal GBS. Some patients with these infections fulfil current criteria for demyelination.

Wrist Circumference-Dependent Upper Limit of Normal for the Cross-Sectional Area Is Superior Over a Fixed Cut-Off Value in Confirming the Clinical Diagnosis of Carpal Tunnel Syndrome.

Introduction: In confirming the clinical diagnosis of carpal tunnel syndrome (CTS), ultrasonography (US) is the recommended first diagnostic test in The Netherlands. One of the most important parameters for an abnormal US result is an increase of the CSA of the median nerve at the carpal tunnel inlet. An earlier study showed that a wrist-circumference dependent cut-off for the upper limit of normal of this CSA might be superior to a fixed cut-off of 11 mm2. In this study we compared three ultrasonography (US) parameters in three large Dutch hospitals. Methods: Patients with a clinical suspicion of CTS and with reasonable exclusion of other causes of their symptoms were prospectively included. A total number of 175 patients were analysed. The primary goal was to compare the number of wrists with an abnormal US result while using a fixed cut-off of 11 mm2 (FC), a wrist circumference-dependent cut-off (y = 0.88 * x-4, where y = ULN and x = wrist circumference in centimetres; abbreviated as WDC), and an intraneural flow related cut-off (IFC). Results: The WDC considered more US examinations to be abnormal (55.4%) than the FC (50.3%) did, as well as the IFC (46.9%), with a statistically significant difference of p = 0.035 and p = 0.001, respectively. The WDC detected 12 abnormal median nerves while the FC did not, and 18 while the IFC did not. The wrist circumference of the patients of these subgroups turned out to be significantly smaller (p < 0.001) when compared with the rest of the group. Conclusion: According to these study results, the wrist-circumference dependent cut-off value for the CSA of the median nerve at the wrist appears to have a higher sensitivity than either a fixed cut-off value of 11 mm2 or cut-off values based on intraneural flow, and may add most value in patients with a smaller wrist circumference.

Neurovestibular Dysfunction and Falls in Parkinson's Disease and Atypical Parkinsonism: A Prospective 1 Year Follow-Up Study.

Our primary aim was to determine whether neurovestibular laboratory tests can predict future falls in patients with either Parkinson's disease (PD) or atypical parkinsonism (AP). We included 25 healthy subjects, 30 PD patients (median Hoehn and Yahr stage 2.5, range 1-4), and 14 AP patients (6 multiple system atrophy, 3 progressive supranuclear palsy, and 5 vascular parkinsonism) in a case-control study design (all matched for age and gender). At baseline, all subjects underwent clinical neurological and neurotological assessments, cervical and ocular vestibular evoked myogenic potentials (VEMP), brainstem auditory evoked potentials (BAEP), subjective visual vertical measurements (SVV), and video nystagmography with caloric and rotary test stimulation. After 1 year follow-up, all subjects were contacted by telephone for an interview about their fall frequency (based upon fall diaries) and about their balance confidence (according to the ABC-16 questionnaire); only one participant was lost to follow-up (attrition bias of 1.4%). Cervical and ocular VEMPs combined with clinical tests for postural imbalance predicted future fall incidents in both PD and AP groups with a sensitivity of 100%. A positive predictive value of 68% was achieved, if only one VEMP test was abnormal, and of 83% when both VEMP tests were abnormal. The fall frequency at baseline and after 1 year was significantly higher and the balance confidence scale (ABC-16) was significantly lower in both the PD and AP groups compared to healthy controls. Therefore, VEMP testing can predict the risk of future fall incidents in PD and AP patients with postural imbalance.

Augmented Diagnostic Accuracy of Ultrasonography for Diagnosing Carpal Tunnel Syndrome Using an Optimised Wrist Circumference-Dependent Cross-Sectional Area Equation.

Introduction: In diagnosing carpal tunnel syndrome (CTS) there is no consensus about the upper limit of normal (ULN) of the cross-sectional area (CSA) of the median nerve at the carpal tunnel inlet. A previous study showed wrist circumference is the most important independent predictor for the ULN. In this study we optimised a wrist circumference-dependent ULN equation for optimal diagnostic accuracy and compared it to the generally used fixed ULN of 11 mm2. Methods: CSA and wrist circumference were measured in a prospective cohort of 253 patients (clinically defined CTS) and 96 healthy controls. An equation for the ULN for CSA was developed by means of univariable regression analysis. We calculated z-scores for all patients and healthy controls, and analysed these scores in a ROC curve and a decision plot. Sensitivity and specificity were determined and compared to fixed ULN values. Results: We found augmented diagnostic accuracy of our newly developed equation y = 0.88 * x -4.0, where y = the ULN of the CSA and x = wrist circumference. This equation has a corresponding sensitivity and specificity of 75% compared to a sensitivity of 70% while using a fixed cut-off value of 11 mm2 (p = 0.015). Conclusion: Optimising the regression equation for wrist circumference-dependent ULN cross-sectional area of the median nerve at the wrist inlet might improve diagnostic accuracy of ultrasonography in patients with carpal tunnel syndrome and seems to be more accurate than using fixed cut-off values.

The Diagnostic Sensitivity for Ulnar Neuropathy at the Elbow Is Not Increased by Addition of Needle EMG of ADM and FDI When Nerve Conduction Studies Are Normal.

Introduction: The main objective of this study was to investigate whether electromyography (EMG) has additional value in the confirmation of the clinical diagnosis of ulnar nerve entrapment at the elbow (UNE) if nerve conduction studies (NCS) are normal. Methods: A prospective cross-sectional cohort observational study was conducted among patients with the clinical suspicion of UNE. A total of 199 arms were included, who were examined according to a standard neurophysiological protocol, i.e., NCS and EMG relevant to the ulnar nerve. Results: NCS were normal in 76 (38.2%) arms. No abnormal spontaneous muscle fiber activity was found with EMG in any of these cases. In 9 arms with normal NCS (11.8%), isolated abnormal MUAP configurations were found with EMG. Of these nine arms one UNE was diagnosed clinically, in which additional ultrasound and repeated NCS/EMG were negative. One had already been diagnosed with neuralgic amyotrophy and one with CTS. The other 6 arms had additional diagnostics which did not reveal an UNE. Conclusion: EMG as part of the standard neurophysiological protocol exclusively in the confirmation of the clinical diagnosis of UNE has limited added value if NCS are normal in a high prior-odds setting. However, removing EMG may prevent detecting concomitant and/or additional differential diagnoses.

Motor Nerve Conduction Tests in Carpal Tunnel Syndrome.

Background: For the preoperatively often required confirmation of clinically defined carpal tunnel syndrome (CTS), sensory as well as motor nerve conduction studies can be applied. The aim of this study was to test the sensitivity of specific motor nerve conduction tests in comparison with, as well as in addition to, sensory nerve conduction tests. Methods: In 162 patients with clinically defined CTS, sensory and motor nerve conduction tests were performed prospectively. Sensitivity and specificity of all tests were computed. Also, Receiver Operating Characteristic (ROC) analyses were conducted. Results: Sensitivity for all sensory tests was at least 79.4% (DIG1). All tests had a specificity of at least 95.7%. The motor conduction test with the highest sensitivity was the TLI-APB (81.3%); its specificity was 97.9%. Conclusion: In the electrophysiological confirmation of CTS, sensory nerve conduction tests and terminal latency index have a high sensitivity. If, however, sensory nerve action potentials cannot be recorded, all motor nerve conduction tests have a high sensitivity.

Validation of the Dutch Version of the Boston Carpal Tunnel Questionnaire.

The Boston Carpal Tunnel Questionnaire (BCTQ) is a scale that has been developed specifically for carpal tunnel syndrome (CTS). It consists of the Functional Status Scale (FSS) and the Symptom Severity Scale (SSS). It is the most widely used patient reported outcome measure in CTS and has been validated in many languages. Although already widely used, psychometric properties of the Dutch version of the BCTQ are yet unknown. The aim of this study was to assess the validity, reliability, responsiveness, and acceptability of the Dutch version. Moreover, this paper focuses the longitudinal validity (the use after an intervention) of the BCTQ, which has not been investigated before. A total of 180 patients completed the BCTQ in addition to a six-point Likert scale for perceived improvement, before and about 6-8 months after carpal tunnel release (CTR). Principal factor analysis revealed that the FSS is unidimensional, consisting of a single latent factor ("functionality") and has a high internal consistency (Cronbach's α = 0.825). However, the SSS has three dimensions, which are all highly internally consistent: "daytime symptoms" (Cronbach's α = 0.805), "nighttime symptoms" (Cronbach's α = 0.835), and "operational capacity" (Cronbach's α = 0.723). Post-treatment, the FSS still consisted of one factor, but the SSS changed in dimensionality, as it had only two factors left post-treatment. The ΔFSS and ΔSSS had good correlation with the six-point Likert scale for perceived improvement (r = 0.524; p < 0.01 and r = 0.574; p < 0.01, respectively), a moderate correlation between FSS and pinch grip (r = 0.259; p < 0.01) was found, and a weak correlation between SSS and pinch grip (r = 0.231; p < 0.01) was found. Standard Response Mean for FSS and SSS was 0.76 and 1.49, respectively. Effect size was 0.92 and 1.96, respectively, both indicating a good responsiveness. Response rate was high (82-84%). We concluded that the Dutch version of the BCTQ has a proper reliability, validity, responsiveness, and acceptability to assess the symptom severity and functional disabilities of CTS patients. Because of multidimensionality, we would recommend to create sum scores of the four different dimensions instead of two. Caution is required when interpreting the results postoperatively, due to the insufficient longitudinal validity of the SSS.

Minimal clinically important difference for the Boston Carpal Tunnel Questionnaire: new insights and review of literature.

No consensus exists about the minimal clinically important difference for the Boston Carpal Tunnel Questionnaire, which hampers its clinical application. This study assessed the minimal clinically important difference of this questionnaire. The Boston Carpal Tunnel Questionnaire was completed by 180 patients, with clinically defined carpal tunnel syndrome, preoperatively and at about 8 months follow-up after carpal tunnel release, together with a six-point scale for perceived improvement. Receiver operator characteristics curves showed that relative changes in Symptom Severity Scale and Functional Status Scale scores correspond better to a clinically relevant improvement than absolute changes. The minimal clinically important difference should be individually calculated from baseline Symptom Severity Scale and Functional Status Scale scores, as patients experiencing more symptoms require more improvement to notice a clinically important difference. By taking this into account, the Boston Carpal Tunnel Questionnaire is more meaningful as an outcome measure in research and clinical practice.

Ultrasound imaging of the ulnar nerve: correlation of preoperative and intraoperative dimensions.

OBJECTIVES: Recently, ultrasonography of the ulnar nerve has been introduced to confirm the diagnosis of ulnar neuropathy at the elbow. The reported diameters appear to be small when compared to those known from surgery (=actual diameter). The actual diameter is compared with the diameter on ultrasonography. PATIENTS AND METHODS: Nine patients that were scheduled for decompression of the ulnar nerve at the elbow underwent an ultrasonographic examination preoperatively and intraoperatively. Longitudinal and transversal sonographical scans were made. The maximal diameters of the ulnar nerve at ultrasound were compared with the maximal diameter of the ulnar nerve intraoperatively. RESULTS: Pre- and intraoperatively on the longitudinal scans, the maximal diameter is smaller than the actual maximal diameter of the ulnar nerve. The difference was 3.7+/-1.0 mm (p<0.001) 3.0+/-1.1 mm (p<0.001), respectively. The same was true on the transverse scans: 1.5+/-1.3 mm (p=0.008) versus 1.1+/-0.6 mm (p=0.001). CONCLUSION: The diameter of the ulnar nerve as determined sonographically suggesting ulnar neuropathy does not correspond with the anatomically determined actual diameter. The maximal diameter can be best estimated with transverse scans.