C.L.A.M. Vleggeert-lankamp

Electrophysiology and morphometry of the Aα- and Aβ-fiber populations in the normal and regenerating rat sciatic nerve

We studied electrophysiological and morphological properties of the Aa- and Ah-fibers in the regenerating sciatic nerve to establish whether these fiber types regenerate in numerical proportion and whether and how the electrophysiological properties of these fiber types are adjusted during regeneration. Compound action potentials were evoked from isolated sciatic nerves 12 weeks after autografting. Nerve fibers were gradually recruited either by increasing the stimulus voltage from subthreshold to supramaximal levels or by increasing the interval between two supramaximal stimuli to obtain the cumulative distribution of the extracellular firing thresholds and refractory periods, respectively. Thus, the mean conduction velocity (MCV), the maximal charge displaced during the compound action potential (Qmax), the mean firing threshold (V50), and the mean refractory period (t50) were determined. The number of myelinated nerve fibers and their fiber diameter frequency distributions were determined in the peroneal nerve. Mathematical modeling applied to fiber recruitment and diameter distributions allowed discrimination of the Aa- and Ah-fiber populations. In regenerating nerves, the number of Aa-fibers increased fourfold while the number of Ah-fibers did not change. In regenerating Aa- and Ah-fibers, the fiber diameter decreased and V50 and t50 increased. The regenerating Aa-fibers’ contribution to Qmax decreased considerably while that of the Ah-fibers remained the same. Correlation of the electrophysiological data to the morphological data provided indications that the ion channel composition of both the Aa- and Ah-fibers are altered during regeneration. This demonstrates that combining morphometric and electrophysiological analysis provides better insight in the changes that occur during regeneration.

Management of lumbar spinal stenosis: a survey among Dutch spine surgeons

BackgroundVarious surgical and non-surgical treatments for lumbar spinal stenosis (LSS) are widely adopted in clinical practice, but high quality randomised controlled trials to support these are often lacking, especially in terms of their relative benefit and risk compared with other treatment options. Therefore, an evaluation of agreement among clinicians regarding the indications and the choice for particular treatments seems appropriate.MethodsOne hundred and six Dutch neurosurgeons and orthopaedic spine surgeons completed a questionnaire, which evaluated treatment options for LSS and expectations regarding the effectiveness of surgical and non-surgical treatments.ResultsResponders accounted for 6,971 decompression operations and 831 spinal fusion procedures for LSS annually. Typical neurogenic claudication, severe pain/disability, and a pronounced constriction of the spinal canal were considered the most important indications for surgical treatment by the majority of responders. Non-surgical treatment was generally regarded as ineffective and believed to be less effective than surgical treatment. Interlaminar decompression was the preferred technique by 68xa0% of neurosurgeons and 52xa0% orthopaedic surgeons for the treatment of LSS. Concomitant fusion was applied in 12xa0% of all surgery for LSS. Most surgeons considered spondylolisthesis as an indication and spinal instability as a definite indication for additional fusion.ConclusionsThe current survey demonstrates a wide variety of preferred treatments of symptomatic LSS by Dutch spine surgeons. To minimise variety, national and international protocols based on high-quality randomised controlled trials and systematic reviews are necessary to give surgeons more tools to support everyday decision-making.

Cervical high-intensity intramedullary lesions in achondroplasia: Aetiology, prevalence and clinical relevance

AbstractObjectivesIn achondroplastic patients with slight complaints of medullary compression the cervical spinal cord regularly exhibits an intramedullary (CHII) lesion just below the craniocervical junction with no signs of focal compression on the cord. Currently, the prevalence of the lesion in the general achondroplastic population is studied and its origin is explored.MethodsEighteen achondroplastic volunteers with merely no clinical signs of medullary compression were subjected to dynamic magnetic resonance imaging (MRI). The presence of a CHII lesion and craniocervical medullary compression in flexed and retroflexed craniocervical positions was explored. Several morphological characteristics of the craniocervical junction, possibly related to compression on the cord, were assessed.ResultsA CHII lesion was observed in 39% of the subjects and in only one of these was compression at the craniocervical junction present. Consequently, no correlation between the CHII lesion and compression could be established. None of the morphological characteristics demonstrated a correlation with the CHII lesion, except thinning of the cord at the site of the CHII lesion.ConclusionsCHII lesions are a frequent finding in achondroplasia, and are generally unaccompanied by clinical symptoms or compression on the cord. Further research focusing on the origin of CHII lesions and their clinical implications is warranted.Key Points• MRI now reveals exquisite detail of the cervical spinal cord.n • Cervical cord lesions are observed in one third of the achondroplastic population.n • These lesions yield high signal intensity on T2 weighted MRI.n • They are generally unaccompanied by clinical symptoms or cord compression.n • Their aetiology is unclear and seems to be unrelated to mechanical causes.

Value of physical tests in diagnosing cervical radiculopathy: a systematic review

BACKGROUND CONTEXTnIn clinical practice, the diagnosis of cervical radiculopathy is based on information from the patients history, physical examination, and diagnostic imaging. Various physical tests may be performed, but their diagnostic accuracy is unknown.nnnPURPOSEnThis study aimed to summarize and update the evidence on diagnostic performance of tests carried out during a physical examination for the diagnosis of cervical radiculopathy.nnnSTUDY DESIGNnA review of the accuracy of diagnostic tests was carried out.nnnSTUDY SAMPLEnThe study sample comprised diagnostic studies comparing results of tests performed during a physical examination in diagnosing cervical radiculopathy with a reference standard of imaging or surgical findings.nnnOUTCOME MEASURESnSensitivity, specificity, likelihood ratios are presented, together with pooled results for sensitivity and specificity.nnnMETHODSnA literature search up to March 2016 was performed in CENTRAL, PubMed (MEDLINE), Embase, CINAHL, Web of Science, and Google Scholar. The methodological quality of studies was assessed using the QUADAS-2.nnnRESULTSnFive diagnostic accuracy studies were identified. Only Spurlings test was evaluated in more than one study, showing high specificity ranging from 0.89 to 1.00 (95% confidence interval [CI]: 0.59-1.00); sensitivity varied from 0.38 to 0.97 (95% CI: 0.21-0.99). No studies were found that assessed the diagnostic accuracy of widely used neurological tests such as key muscle strength, tendon reflexes, and sensory impairments.nnnCONCLUSIONSnThere is limited evidence for accuracy of physical examination tests for the diagnosis of cervical radiculopathy. When consistent with patient history, clinicians may use a combination of Spurlings, axial traction, and an Arm Squeeze test to increase the likelihood of a cervical radiculopathy, whereas a combined results of four negative neurodynamics tests and an Arm Squeeze test could be used to rule out the disorder.

Decompression with or without concomitant fusion in lumbar stenosis due to degenerative spondylolisthesis: a systematic review

PurposeThe primary objective of this systematic review is to compare the outcome after decompression with and without concomitant instrumented fusion in patients with lumbar stenosis and degenerative spondylolisthesis. Does adding fusion to simple decompression lead to better results?MethodsPubMed, Embase, CENTRAL, Cochrane, Web of Science, CINAHL and Academic Search Premier were searched. All studies comparing outcome of decompression alone to decompression with concomitant-instrumented fusion in patients suffering from symptomatic lumbar stenosis with degenerative spondylolisthesis were included. Risk of bias was assessed using an adapted version of the Cowley checklist.ResultsEleven studies were included in the analysis involving 3119 patients in total. In the majority of studies, including two RCTs, clinical outcome of both patient groups was comparable regarding most clinical outcome measures.ConclusionCurrently there is not enough evidence that adding instrumented fusion to a decompression leads to superior outcomes compared to decompression only in patients with lumbar stenosis and degenerative spondylolisthesis. The most important clinical outcome measures, including the ODI, show comparable results. Therefore, the least invasive and least costly procedure, being decompression alone, is preferred in patients with low-grade spondylolisthesis with predominant leg pain.Graphical abstractThese slides can be retrieved under Electronic Supplementary Material.

Lumbar spinal canal dimensions measured intraoperatively after decompression are not properly rendered on early postoperative MRI.

BackgroundIn cases of lumbar spinal stenosis (LSS) treated with surgical decompression, a postoperative magnetic resonance imaging (MRI) is sometimes required. In the experience of the investigators of this study, the obtained decompression observed on early postoperative MRI tends to be disappointing compared to the decompression achieved intraoperatively. This raises the question of whether the early postoperative MRI, performed after lumbar decompression, is a fair representation of the ‘real’ decompression. This study investigated the correlation between intraoperative and postoperative measurements of the lumbar spinal canal.MethodTwenty patients with LSS underwent surgical decompression on a single level. The orthopaedic surgeon performed direct intraoperative measurements of width, length and height of the spinal canal. Preoperative supine MR images and postoperative prone and supine MR images were acquired. Two radiologists (R.B. and M.G.) measured width, length and height of the spinal canal on the preoperative and postoperative MRIs. Intraoperative measurements were compared to measurements on postoperative MRI in prone position (thus reproducing the intraoperative situation) to avoid positioning bias. Preoperative and postoperative measurements on MR images were also compared. In addition to this, postoperative measurements on supine and prone MR images were also compared.ResultsInterobserver reliability for MRI measurements by both radiologists was generally excellent (intraclass correlation coefficients ≥0.71). The postoperative spinal canal dimensions improved on both prone and supine MRI compared to the preoperative imaging (Pu2009<u20090.05). Intraoperatively measured dimensions demonstrated a significantly greater height (difference 2.8u2009±u20093.3 [R.B.] and 1.9u2009±u20093.7 [M.G.]) and greater width (difference 2.1u2009±u20093.2 [R.B.] and 2.5u2009±u20092.7 [M.G.]) compared to postoperative MRI in the prone position (Pu2009<u20090.05). Postoperative dural sac height was greater on the supine MRI compared to the prone MRI (Pu2009<u20090.05).ConclusionsSurgical decompression of the spinal canal effectively decreases the compression of the dural sac. However, early postoperative MRI after lumbar decompression does not adequately represent the decompression achieved intraoperatively.

Radiological follow-up after implanting cervical disc prosthesis in anterior discectomy: a systematic review

OBJECTIVEnThe objective of this study was to review current literature on the comparison of the radiological outcome of cervical arthroplasty with fusion after anterior discectomy for radiculopathy.nnnMATERIALS AND METHODSnA literature search was performed in PubMed, Embase, Web of Science, Cochrane, CENTRAL, and CINAHL using a sensitive search string combination. Studies were selected by predefined selection criteria (patients exclusively suffering from cervical radiculopathy), and risk of bias was assessed using a validated Cochrane checklist adjusted for this purpose. Additionally, an overview of results of articles published in 21 meta-analyses was added, considering a group of patients with myelopathy with or without radiculopathy.nnnRESULTSnSeven articles that compared intervertebral devices in patients with radiculopathy (excluding patients with myelopathy) were included in the study. Another 31 articles were studied as a mixed group, including patients with myelopathy and radiculopathy. Apart from three studies with low risk of bias, all other articles showed intermediate or high risk of bias. Heterotopic ossification was reported to be present in circa 10% of patients, seemingly predominant in patients with radiculopathy, with a very low level of evidence. Radiological signs of adjacent segment disease were present at baseline in 50% of patients, and there is a low level of evidence that this increased more (10%-20%) in the fusion group at long-term follow-up. However, this was only studied in the mixed study population, which is degenerative by diagnosis.nnnCONCLUSIONnAlthough the cervical disc prosthesis was introduced to decrease adjacent level disease, convincing radiological evidence for this benefit is lacking. Heterotopic ossification as a complicating factor in the preservation of motion of the device is insufficiently studied. Regarding purely radiological outcomes, currently, no firm conclusion can be drawn for implanting cervical prosthesis versus performing fusion.

Lumbar spinal canal MRI diameter is smaller in herniated disc cauda equina syndrome patients

Introduction Correlation between magnetic resonance imaging (MRI) and clinical features in cauda equina syndrome (CES) is unknown; nor is known whether there are differences in MRI spinal canal size between lumbar herniated disc patients with CES versus lumbar herniated discs patients without CES, operated for sciatica. The aims of this study are 1) evaluating the association of MRI features with clinical presentation and outcome of CES and 2) comparing lumbar spinal canal diameters of lumbar herniated disc patients with CES versus lumbar herniated disc patients without CES, operated because of sciatica. Methods MRIs of CES patients were assessed for the following features: level of disc lesion, type (uni- or bilateral) and severity of caudal compression. Pre- and postoperative clinical features (micturition dysfunction, defecation dysfunction, altered sensation of the saddle area) were retrieved from the medical files. In addition, anteroposterior (AP) lumbar spinal canal diameters of CES patients were measured at MRI. AP diameters of lumbar herniated disc patients without CES, operated for sciatica, were measured for comparison. Results 48 CES patients were included. At MRI, bilateral compression was seen in 82%; complete caudal compression in 29%. MRI features were not associated with clinical presentation nor outcome. AP diameter was measured for 26 CES patients and for 31 lumbar herniated disc patients without CES, operated for sciatica. Comparison displayed a significant smaller AP diameter of the lumbar spinal canal in CES patients (largest p = 0.002). Compared to average diameters in literature, diameters of CES patients were significantly more often below average than that of the sciatica patients (largest p = 0.021). Conclusion This is the first study demonstrating differences in lumbar spinal canal size between lumbar herniated disc patients with CES and lumbar herniated disc patients without CES, operated for sciatica. This finding might imply that lumbar herniated disc patients with a relative small lumbar spinal canal might need to be approached differently in managing complaints of herniated disc. Since the number of studied patients is relatively small, further research should be conducted before clinical consequences are considered.