Giuseppe de Scisciolo

Monitoring of somatosensory evoked potentials during carotid endarterectomy

SummarySomatosensory evoked potentials (SEPs) were monitored in the course of 368 carotid endarterectomies (CEAs) carried out in 312 patients. In an initial group of 26 patients the shunt was used routinely while in a second group, involving 342 CEAs, it was applied selectively on the basis of modifications which the SEP underwent during clamping. The criterion for shunting was the progressive reduction, up to 50%, of the N20-P25 amplitude. New postoperative neurological deficits appeared in 6 patients, all of whom displayed a transitory SEP flattening. The SEPs of 2 of these returned to normal by the time they awoke and both showed a clinical deficit homolateral to the operated side. In only 2 cases did the deficit fail to regress completely and their postoperative CT scans revealed ischaemic lesions. A positive relationship emerged between SEP changes and back pressure values; nonetheless, as many as 75% of the patients with low residual back pressure values (< 25 mm Hg) tolerated the clamping. SEP monitoring appears to provide a reliable basis for selectively applying a shunt when there is a high risk of haemodynamic ischaemia during clamping.

Diagnosis and therapy for neurogenic bladder dysfunctions in multiple sclerosis patients

Neurogenic lower urinary tract dysfunctions are common in patients with multiple sclerosis and for most of them urinary dysfunction has the most negative impact on their social life. No correlation exists between clinical urinary symptoms and urodynamic patterns. Abnormal urodynamic patterns may be present in asymptomatic patients. Both clinical and urodynamic findings may change during the course of the illness. Early diagnostic approach and scheduled follow-ups are mandatory in order to prevent upper urinary tract complications and improve quality of life (QoL).

Neurological damage in patients irradiated twice on the spinal cord: a morphologic and electrophysiological study

We reviewed the files of 950 patients treated for Hodgkins disease since 1966 and were able to find five patients treated with radiochemotherapy and irradiated twice on volumes including a cord segment, at various time intervals, and surviving until now. Seven patients with comparable clinical and therapeutic features, but not reirradiated on the cord, were chosen as a control group and were examined with the same diagnostic procedures. The cumulative cord dose in the reirradiated patients was recalculated and ranged from 50 to 70 Gy. All these patients and the control cases were followed up for more than 10 years and presented no or only minor neurological symptoms. We compare the results of both magnetic resonance imaging (MRI) and electrophysiological studies (spinal and scalp recorded somatosensory evoked potentials--SEPs) in an attempt to define the characteristics of the subclinical damage present in these patients. While no cord abnormality was demonstrated with MRI, electrophysiological studies evidenced a clear difference between cases and controls, as far as the D10-P1 conduction time and SEPs average amplitude are concerned. Advantages and drawbacks of a wider use of electrophysiological methods in research work on cord radiation damage are presented, along with the possible implications of the results obtained for the understanding of the pathogenesis and of the dose dependence of radiation myelitis (RM).

Anesthetic induction with thiopental: its effect on scalp topography of median nerve somatosensory evoked potentials

The effects on median nerve somatosensory evoked potentials (SEPs) of analgesic doses of fentanyl, meperidine or morphine and of sodium thiopental (STP) anesthesia (4 mg/kg) were tested in 36 surgical patients. We also explored changes in SEP components as a function of their scalp location. Before and after medication, responses were recorded from the scalp overlying the parietal cortex (ipsi‐ and contralateral to the stimulated arm) and the precentral (contralateral) cortex. None of the three opiates affected SEP latencies or amplitudes. The barbiturate increased the amplitudes of subcortical and early cortical components (N18, N20, P22, P25), whose latencies, however, were not significantly modified. The effect of STP on later SEP cortical components depended on their scalp topography: parietal N33 and P45 underwent significant changes in both latency and amplitude, whereas precentral N30 showed a significant amplitude increase only. Thiopental anesthesia produces clearer short‐latency SEP recordings, from both parietal (components N20—P25) and precentral (P22, N30) areas.

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.