A. Cassardo

Proposal of a new criterion for electrodiagnosis of meralgia paresthetica by evoked potentials

We examined 19 subjects with meralgia paresthetica (bilateral in three cases), recording bilateral somatosensory-evoked potentials (SSEPs) after stimulation of the tibial posterior nerve (TPN) and cutaneous stimulation in the region of the lateral femoral cutaneous nerve (LFCN). We calculated the difference between TPN SSEPs and LFCN SSEPs cortical potentials, identifying a temporal parameter that we termed DSEP. We defined DSEP normal values in a control group. DSEP evaluation showed good sensitivity and specificity (85.7% and 82.4%, respectively; accuracy, 83.3%) in discriminating affected limbs from unaffected. The main advantage of this method is to disengage from the necessity of contralateral comparison of LFCN recordings, joined with a reduction of interindividual variability of LFCN SSEPs amplitude and latency that often causes a lower sensitivity of other methods. As an interesting consideration, DSEP evaluation appears to mark out a possible subclinical involvement of LFCN in the asymptomatic side of patients with meralgia paresthetica.

29. Can the neurophysiologic study help for the right diagnosis of narrow canal

Spinal stenosis is an abnormal narrowing of the spinal column that may occur in any of the regions of the spine. The most common clinical features are lumbar spinal stenosis (LSS). There are three major types of lumbar stenosis, and accurate identification is vital to stenosis treatment: lateral, central and foraminal. If the narrowing is substantial, it causes compression of the nerves, which causes the painful symptoms of LSS. In our laboratory were studied 136 patients (41–81 years), both asymptomatic and symptomatic neurophysiological test were performed in all patients. EMG/ENG was abnormal in all symptomatic patients. In accordance with many studies there was no correlation between clinical symptoms and radiological findings; in fact, even if the neuroimaging investigation can distinguish mono- and multisegmental stenosis and its severity, often there is not correlation between the pain and functional symptoms. The electrophysiological recordings indicate a lumbar root involvement that is complementary to the history and neurological examination of the patient as well as the neuroimaging Therefore we think that for a correct diagnosis of LSS only the combination of clinical, radiological and neurophysiological recordings could be useful and may be helpful for the planning and selection of appropriate and early therapeutic approaches.

90. Cost-benefit analysis of multimodal intraoperative monitoring during spine surgery

Multimodal intraoperative neurophysiological monitoring (IOM) during spine surgery was introduced in clinical practice to reduce the risk of permanent neurological deficit post-surgery. The early detection of changes in neurophysiological parameters during surgical procedure, makes it possible to reverse the damage before it becomes permanent. The economic impact of the IOM, a rather difficult topic, was estimated with sufficient accuracy. We have done a review of the costs, in our department, ranging into a minimum of 220 euro for the peripheral nervous system and a maximum of 630 euro for spine surgery. Even if the rate of complications during IOM remains very low (about 1%), the costs of performing IOM surely do not exceed those of health care for the injured patients, so that the economic burden of neurological damage justifies widely the cost of the procedure. Moreover, indirect costs are often underestimated: loss of job, career setbacks of the patient or a family member close to him. One aspect that can not be measured is the impact of a possible psychological and social permanent deficit, especially when the affection of a specific function limits the chances of social relationship.

89. Segmental muscular neurogenic hypertrophy: Two case reports with different site of lesion

The usual semiotic sign of motor neuron damage is hypotrophy of target muscle. However, in rare cases, a motor neuron damage results in hypertrophy: this is principally due to a chronic triggering of spontaneous activity in affected motor units, with continuous or subcontinuous activation of target muscular fibers. Muscular neurogenic hypertrophy was reported during radiculopathy, mononeuropathy, focal myelopathy, tethered cord syndrome, chronic inflammatory demyelinating polyneuropathy. In this report we present classification of muscular neurogenic hypertrophy, based on topography, etiology and type of spontaneous activity possibly observed. We present also two cases: the first one due to spondyloarthrosis associated with T11–T12 discopathy, the second one due to ischiatic nerve neuropathy related to proximal femur fracture.

P1026: Neurophysiological examinations in two cases of rare syndrome: Hirayama disease and Fraccaro syndrome

Result: Clinical diagnosis was mainly based on dysmorphic features and concentric needle EMG changes showing spontaneous, continuous high frequency myotonic and/or complex repetitive discharges. The study group comprised 3 males and 3 females with a diagnosis of SJS, aged between 2 and 7 years. All except one had consanguineous parents. Physical examination revealed generalized muscle hypertrophy in four cases, in addition to muscle stiffness, joint contractures, orthopedic problems of varying severity and typical facial features like blepharophimosis, pursed lips, and microstomia, observed in all cases. All patients except one had short stature. In one patient molecular analysis confirmed homozygosity for p.R1550C mutation in exon 37 of the perlacan gene. Analysis of perlecan expression by fibroblast cells revealed deficiency of perlecan mRNA and reduced perlecan immunstaining in two patients. We considered 2 cases who had metaphyseal dysplasia from birth and were more severely affected corresponded to SJS-type 1b and the others corresponded to SJS type 1a. A needle EMG examination in all the patients showed continuous spontaneous activity including myotonia and complex repetitive discharges. In two patients, the myotonia was responsive to carbamazepine and in one, to phenytoin. Conclusion: Clinical features of SJS may vary from mild myotonia with subtle radiological signs to severe myotonia with contractures. Although the diagnosis is mainly clinical and confirmed by immunohistochemical and molecular studies, EMG examination supports the diagnosis.

119. Dermatomal sensory evoked potentials in sensory neuropathies of lower limb

Peripheral neuropathies of sensory nerves in thighs and legs are uncommon and also hard to confirm by neurophysiologic tests. Often neurography and somatosensory evoked potentials from mixed nerve stimulation are not enough selective, sensitive or even useable in those clinical hypothesis. Dermatomal sensory evoked potentials (dSEP) obtained stimulating cutaneous regions with a specific innervation can be an useful tool to investigate those neuropathies. The key of this method, because of frequent anatomic variants and topographic embedding of terminal nerve fibres, is that maximum care must be placed in the choice of cutaneous regions to stimulate. In our experience, we found some cases in which dSEP confirmed a clinical suspicion of sensitive neuropathy. We studied Genitofemoral, Iliohypogastric, Ilioinguinal, Lateral Femoral Cutaneous, Saphenous, Calcanear nerves. We will present our normative data and some case reports.

115. The role of neurophysiological technician in pelvic floor practice

Based on our current understanding of the neuroanatomy and neurophysiology of the pelvic floor, we can choose which neurophysiological tests could be record, in order to perform an accurate instrumental examination of central and peripheral nervous system. That’s useful for a correct diagnosis and therapy for each specific clinical picture (neurogenic bladder, incontinence, constipation, urinary retention, male impotence, pelvic pain…). A skillful neurophysiological technician should have confidence with rationale, clinical utility, strengths and potential pitfalls for each of the commonly used neurophysiological tests of the pelvic floor: pudendal somatosensory evoked potential (SEPs), sympathetic skin response (SSR), sacral reflex (SR), perineal muscles electromyography (EMG), motor evoked potential (MEP). Moreover a good technician must have an adequate competence and experience in recording these specific exams in that contest; his role include also instrument’s sterilization and care, collection of case history, test’s explanation, guide of patients in positioning, tasks and movements, keep them calm and relaxed to get collaboration and allow examination’s good recording.

34. The neurophysiological evaluation in spinal cord injury during acute stage

ASIA Impairment Scale, (AIS) is essential to assess acute spinal cord injury. Could the neurophysiological investigations (NI) add value to AIS during acute stage? We have to consider if instrumental evaluation could add more information in diagnosis-prognosis and in therapy – rehabilitative treatment. 1. Timing 2. Which exam 3. Added prognostic value of each exam 1. Right timing is not indicate in literature. However Authors agree about no effect of spinal shock over early components of SEPs, SSR and (electrical) MEPs. Moreover only NI is useful to asses diagnostic-prognostic overview of uncooperative or sedated patients. 2. To evaluate site and extension of the lesion, SEPs and MEPs are common performed. SSR could give useful information about the possibility to occur in autonomic dysriflexia. 3. Hand ability outcome is related to Median-Ulnar nerves SEPs; lesions seriousness and ambulatory outcome are related to both Tibial posterior nerve and sacral SEP; bladder somatic function is related to Pudendal nerve SEP. In cooperative patients no more information are added to clinical examination by MEPs even if these exams have good correlation, but MEPs could add more information about site lesion. Combination of AIS and NI can increase significantly predictivity of functional outcome with high reliability.