Stanislav Voháňka

Conservative treatment versus surgery in spondylotic cervical myelopathy: a prospective randomised study

Abstract A prospective randomised 2-year study was performed to compare the conservative and operative treatment of mild and moderate forms of spondylotic cervical myelopathy (SCM). Forty-eight patients presenting with the clinical syndrome of SCM, with a modified Japanese Orthopaedic Association (mJOA) score of 12 points or more, were randomised into two groups. Group A, treated conservatively, consisted of 27 patients, mean age 55.6 ± 8.6 years, while group B was treated surgically (21 patients, mean age 52.7 ± 8.1 years). The clinical outcome was measured by the mJOA score, recovery rate (RR), timed 10 m walk, score of daily activities (recorded by video and evaluated by two observers blinded to the therapy), and by the subjective assessment of the patients at 6, 12, and 24 months of the follow-up. There was, on average, no significant deterioration in mJOA score, recovery ratio, or timed 10 m walk within either group during the 2 years of follow-up. In the surgery group there was a slight decline in the scores for daily activities and subjective evaluation. A comparison of the two groups showed no significant differences in changes over time in mJOA score or quantified gait, but there were significant differences in the score of daily activities recorded by video at 24 months, which was a little lower in the surgical group, and also in RR and subjective evaluation, which were both worse in the surgical group at months 12 and 24. However, at month 6, this last parameter was significantly better in the surgical than in conservative group. Surgical treatment of mild and moderate forms of SCM in the present study design, comprising the patients with no or very slow, insidious progression and a relatively long duration of symptoms, did not show better results than conservative treatment over the 2-year follow-up.

The value of somatosensory- and motor-evoked potentials in predicting and monitoring the effect of therapy in spondylotic cervical myelopathy. Prospective randomized study.

STUDY DESIGN A 2-year follow-up prospective randomized electrophysiologic and clinical study of patients with spondylotic cervical myelopathy. OBJECTIVE To assess the value of somatosensory- and motor-evoked potentials in the evaluation and prediction of the effect of therapy. SUMMARY OF BACKGROUND DATA Previous studies have yielded conflicting data concerning the correlation between the changes in evoked potential parameters and the clinical postsurgical outcome in spondylotic cervical myelopathy. METHODS Sixty-one patients with magnetic resonance images suggesting spondylotic cervical cord compression and clinical signs of cervical myelopathy were divided into two groups according to the degree of clinical cervical cord involvement. The 49 patients with mild and moderate spondylotic cervical myelopathy were randomized into groups that underwent either surgical or conservative therapy. Patients were evaluated clinically and by the means of somatosensory- and motor-evoked potentials. RESULTS The clinical and evoked potential changes showed good correlation on the group level, but poor correlation intraindividually. There were no significant evoked potential and clinical group changes after 6 months and 2 years in the mild myelopathy group treated either surgically and conservatively, whereas patients with severe myelopathy displayed significant improvement in clinical and evoked potential parameters after surgery. In a subgroup of patients, the isolated segmental medullar N13 abnormality could potentially predict favorable postsurgical clinical outcome. CONCLUSIONS Longitudinal evoked potentials showed limited use for evaluating the results of therapy in an individual patient. They could be useful in the group assessment of therapy results and in labeling a subgroup of patients with potentially favorable postsurgical outcome.

The value of somatosensory and motor evoked potentials in pre-clinical spondylotic cervical cord compression

Abstract Previous studies have yielded conflicting data concerning the value of evoked potential parameters in the assessment of clinical relevance of cervical cord compression in clinically “silent” cases. The aim of this study was to assess the value of somatosensory (SEP) and motor evoked potentials (MEP) in the evaluation and prediction of the clinical course, by means of a 2-year follow-up prospective electrophysiological and clinical study performed in patients with clinically “silent” spondylotic cervical cord compression. Thirty patients with MR signs of spondylotic cervical cord compression but without clinical signs of myelopathy were evaluated clinically and using SEPs and MEPs during a 2-year period. The results of the study showed that SEPs and MEPs documented subclinical involvement of cervical cord in 50% of patients with clinically “silent” spondylotic cervical cord compression. During the 2-year period clinical signs of cervical myelopathy were observed in one-third of patients with entry EP abnormality in comparison with no patients with normal EP tests. Combined SEPs and MEPs proved to be a valuable tool in the assessment of the functional relevance of subclinical spondylotic cervical cord compression. Normal EP findings predict a favourable 2-year clinical outcome.

Analysis of histopathologic and molecular pathologic findings in Czech LGMD2A patients

Limb‐girdle muscular dystrophy type 2A (LGMD2A) is an autosomal‐recessive disorder characterized by selective atrophy and progressive weakness of proximal girdle muscles. LGMD2A, the most prevalent form of LGMD, is caused by mutations in the CAPN3 gene that encodes the skeletal muscle–specific member of the calpain family, calpain‐3 (p94). We examined the histopathologic and molecular pathologic findings in 14 Czech LGMD2A patients. Analysis of the CAPN3 gene was performed at the mRNA level, using reverse transcription–polymerase chain reaction (RT‐PCR) and sequencing, and/or DNA level, using PCR and denaturing high‐performance liquid chromatography (DHPLC). Our results confirm that mutation 550delA is the most frequent CAPN3 defect in Czech LGMD2A patients (9 alleles of 28). Furthermore, we established that, in a patient with the 550delA/R490W genotype, mRNA carrying frameshift mutation 550delA was not detected, probably due to its degradation by nonsense‐mediated mRNA decay. In muscle biopsies of two LGMD2A patients, a neurogenic pattern simulating a neurogenic lesion was observed. Immunoblot analysis revealed the deficiency of p94 in all genetically confirmed cases of LGMD2A, and secondary dysferlin deficiency was demonstrated on muscle membranes in 6 patients using immunofluorescence. Thus, we find a combination of DNA and mRNA mutational analysis to be useful in the diagnosis of LGMD2A. Moreover, our study expands the spectrum of calpainopathies to cases that simulate a neurogenic lesion in muscle biopsies, and the knowledge of possible secondary deficiencies of muscular proteins also contributes to a diagnosis of LGMD2A. Muscle Nerve, 2006

Median nerve mononeuropathy in spondylotic cervical myelopathy:double crush syndrome?

Abstract We studied the association between spondylotic cervical myelopathy (SCM) and median nerve mononeuropathy (MNM) and examined the validity of the double-crush hypothesis. Sixty consecutive patients with clinically overt spondylotic cervical myelopathy were examined by means of nerve conduction studies, electromyography, and median nerve somatosensory evoked potentials; the frequency of the electrophysiological signs of focal MNM at the wrist was compared with that of a control group comprising 100 sex- and age-matched patients. Electrophysiological signs of MNM were found in 20 myelopathic patients (33%) in comparison with an 11% prevalence in the control group (P < 0.05). The signs of motor anterior horn cell lesion at the C8-Th1 level and concomitant motor axonal MNM ipsilaterally were found in three hands, while the signs of sensory axonal loss at C6-7 segments due to ganglionic or postganglionic sensory lesion outside the wrist and concomitant sensory axonal MNM were present in one hand. While demonstrating a statistically significant association between SCM and MNM, we found no evidence of an etiological relationship between these two conditions. Electrophysiological signs of MNM fail anatomical (segmental level and side) and pathophysiological (axonal type of lesion) requirements of the double-crush hypothesis in most of patients with concomitant SCM and MNM.

CLCN1 Mutations in Czech Patients with Myotonia Congenita, In Silico Analysis of Novel and Known Mutations in the Human Dimeric Skeletal Muscle Chloride Channel

Myotonia congenita (MC) is a genetic disease caused by mutations in the skeletal muscle chloride channel gene (CLCN1) encoding the skeletal muscle chloride channel (ClC-1). Mutations of CLCN1 result in either autosomal dominant MC (Thomsen disease) or autosomal recessive MC (Becker disease). The ClC-1 protein is a homodimer with a separate ion pore within each monomer. Mutations causing recessive myotonia most likely affect properties of only the mutant monomer in the heterodimer, leaving the wild type monomer unaffected, while mutations causing dominant myotonia affect properties of both subunits in the heterodimer. Our study addresses two points: 1) molecular genetic diagnostics of MC by analysis of the CLCN1 gene and 2) structural analysis of mutations in the homology model of the human dimeric ClC-1 protein. In the first part, 34 different types of CLCN1 mutations were identified in 51 MC probands (14 mutations were new). In the second part, on the basis of the homology model we identified the amino acids which forming the dimer interface and those which form the Cl- ion pathway. In the literature, we searched for mutations of these amino acids for which functional analyses were performed to assess the correlation between localisation of a mutation and occurrence of a dominant-negative effect (corresponding to dominant MC). This revealed that both types of mutations, with and without a dominant-negative effect, are localised at the dimer interface while solely mutations without a dominant-negative effect occur inside the chloride channel. This work is complemented by structural analysis of the homology model which provides elucidation of the effects of mutations, including a description of impacts of newly detected missense mutations.

Quantitative analysis of CAPN3 transcripts in LGMD2A patients: involvement of nonsense-mediated mRNA decay.

Limb girdle muscular dystrophy type 2A (LGMD2A) is caused by single or small nucleotide changes widespread along the CAPN3 gene, which encodes the muscle-specific proteolytic enzyme calpain-3. About 356 unique allelic variants of CAPN3 have been identified to date. We performed analysis of the CAPN3 gene in LGMD2A patients at both the mRNA level using reverse transcription-PCR, and at the DNA level using PCR and denaturing high performance liquid chromatography. In four patients, we detected homozygous occurrence of a missense mutation or an in-frame deletion at the mRNA level although the DNA was heterozygous for this mutation in conjunction with a frame-shift mutation. The relationship observed in 12 patients between the quantity of CAPN3 mRNA, determined using real-time PCR, and the genotype leads us to propose that CAPN3 mRNAs which contain frame-shift mutations are degraded by nonsense-mediated mRNA decay. Our results illustrate the importance of DNA analysis for reliable establishment of mutation status, and provide a new insight into the process of mRNA decay in cells of LGMD2A patients.

Are subjects with spondylotic cervical cord encroachment at increased risk of cervical spinal cord injury after minor trauma

The aim of the study was to analyse the risk of symptomatic myelopathy after minor trauma in patients with asymptomatic spondylotic cervical spinal cord encroachment (ASCCE). In a cohort of 199 patients with ASCCE, previously followed prospectively in a study investigating progression into symptomatic myelopathy, the authors looked retrospectively for traumatic episodes that may have involved injury to the cervical spine. A questionnaire and data file analysis were employed to highlight whatever hypothetical relationship might emerge with the development of symptomatic myelopathy. Fourteen traumatic episodes in the course of a follow-up of 44 months (median) were recorded in our group (who had been instructed to avoid risky activities), with no significant association with the development of symptomatic myelopathy (found in 45 cases). Only three minor traumatic events without fracture of the cervical spine were found among the symptomatic myelopathy cases, with no chronological relationship between trauma and myelopathy. Furthermore, 56 traumatic spinal cord events were found before the diagnosis of cervical cord encroachment was established, with no correlation to either type of compression (discogenic vs osteophytic). In conclusion, the risk of spinal cord injury after minor trauma of the cervical spine in patients with ASCCE appeared to be low in our cohort provided risky activities in these individuals are restricted. Implementation of preventive surgical decompression surgery into clinical practice in these individuals should be postponed until better-designed studies provide proof enough for it to take precedence over a conservative approach.

Autosomal recessive limb-girdle muscular dystrophies in the Czech Republic

BackgroundAutosomal recessive limb-girdle muscular dystrophies (LGMD2) include a number of disorders with heterogeneous etiology that cause predominantly weakness and wasting of the shoulder and pelvic girdle muscles. In this study, we determined the frequency of LGMD subtypes within a cohort of Czech LGMD2 patients using mutational analysis of the CAPN3, FKRP, SGCA, and ANO5 genes.MethodsPCR-sequencing analysis; sequence capture and targeted resequencing.ResultsMutations of the CAPN3 gene are the most common cause of LGMD2, and mutations in this gene were identified in 71 patients in a set of 218 Czech probands with a suspicion of LGMD2. Totally, we detected 37 different mutations of which 12 have been described only in Czech LGMD2A patients. The mutation c.550delA is the most frequent among our LGMD2A probands and was detected in 47.1% of CAPN3 mutant alleles. The frequency of particular forms of LGMD2 was 32.6% for LGMD2A (71 probands), 4.1% for LGMD2I (9 probands), 2.8% for LGMD2D (6 probands), and 1.4% for LGMD2L (3 probands).Further, we present the first results of a new approach established in the Czech Republic for diagnosis of neuromuscular diseases: sequence capture and targeted resequencing. Using this approach, we identified patients with mutations in the DYSF and SGCB genes.ConclusionsWe characterised a cohort of Czech LGMD2 patients on the basis of mutation analysis of genes associated with the most common forms of LGMD2 in the European population and subsequently compared the occurrence of particular forms of LGMD2 among countries on the basis of our results and published studies.

Muscular dystrophies and myopathies: the spectrum of mutated genes in the Czech Republic

Inherited neuromuscular disorder (NMD) is a wide term covering different genetic disorders affecting muscles, nerves, and neuromuscular junctions. Genetic and clinical heterogeneity is the main drawback in a routine gene‐by‐gene diagnostics. We present Czech NMD patients with a genetic cause identified using targeted next‐generation sequencing (NGS) and the spectrum of these causes. Overall 167 unrelated patients presenting NMD falling into categories of muscular dystrophies, congenital muscular dystrophies, congenital myopathies, distal myopathies, and other myopathies were tested by targeted NGS of 42 known NMD‐related genes. Pathogenic or probably pathogenic sequence changes were identified in 79 patients (47.3%). In total, 37 novel and 51 known disease‐causing variants were detected in 23 genes. In addition, variants of uncertain significance were suspected in 7 cases (4.2%), and in 81 cases (48.5%) sequence changes associated with NMD were not found. Our results strongly indicate that for molecular diagnostics of heterogeneous disorders such as NMDs, targeted panel testing has a high‐clinical yield and should therefore be the preferred first‐tier approach. Further, we show that in the genetic diagnostic practice of NMDs, it is necessary to take into account different types of inheritance including the occurrence of an autosomal recessive disorder in two generations of one family.