The Insertion of Electrodes in the Brain for Electrophysiological Recording or Chronic Stimulation Is Not Associated With Any Biochemically Detectable Neuronal Injury

OBJECTIVE

The aim of this study was to evaluate the degree of brain tissue injury that could be potentially induced by the introduction of a) microrecording electrodes, b) macrostimulation electrodes, or c) chronic stimulation electrodes. We aimed to evaluate whether the use of five simultaneous microrecording tracks is associated with any brain injury not detectable by conventional imaging such as CT or MRI.

MATERIALS AND METHODS

The study included 61 patients who underwent surgery for implantation of 121 DBS leads. In all cases, five simultaneous tracts were utilized for microelectrode recordings. All patients underwent measurements of serum S-100b at specific time points as follows: a) prior to the operation, and b) intraoperatively at specific stages of the procedure: 1) after opening the burr hole, 2) after the insertion of microrecording electrodes, 3) during macrostimulation, 4) at the end of the operation, and 5) on the first postoperative day.

RESULTS

The levels of serum S-100B protein remained within the normal range during the entire period of investigation in all patients with the exception of two cases. In both patients, the procedure was complicated by intraparenchymal hemorrhage visible in neuro-imaging. The first patient developed a small intraparenchymal hemorrhage, visible on the postoperative MRI, with no neurological deficit. The second patient experienced a focal epileptic seizure after the insertion of the right DBS chronic lead and the postoperative CT scan revealed a right frontal lobe hemorrhage.

CONCLUSION

These results strongly indicate that the insertion of either multiple recording electrodes or the implantation of chronic electrodes in DBS does not increase the risk of brain hemorrhage or of other intracranial complications, and furthermore it does not cause any biochemically detectable brain tissue damage.

Stereotactic neurosurgery for disabling tremor in multiple sclerosis: thalamotomy or deep brain stimulation?

Disabling tremor is common in multiple sclerosis and up to 75% of patients experience tremor at some point during their disease. The treatment of this tremor, however, remains challenging. Pharmacotherapy in general has been disappointing and stereotactic neurosurgery is becoming increasingly popular. However, the results of stereotactic treatments reported are variable and no systematic review has been performed. The aim of this study was to assess the role of thalamotomy and deep brain stimulation in the treatment of tremor in multiple sclerosis, and to compare the differences in efficacy and safety between the two techniques. We identified the relevant published studies and cases by searching the MEDLINE, EMBASS and the references lists of related articles, and performed a systematic review and assessment of the full texts of all articles selected. Initial tremor suppression was seen in 93.8% of patients who had thalamotomy and 96% in those who had deep brain stimulation. A total of 63.5% of patients had persistent tremor suppression at 12 months or more after thalamotomy. Twelve results for deep brain stimulation were not available in the reviewed literature. Functional improvement was seen only in 47.8% of those who underwent thalamotomy as opposed to 85.2% of those who had deep brain stimulation. While three of the four reported deaths were in patients who underwent thalamotomy, three of the four procedure-related haemorrhages followed DBS. Other common adverse effects like hemiparesis, dysarthria, swallowing difficulties, balance disorder, etc., was reported in both procedures. Numerous studies have attempted to assess the efficacy and safety of thalamotomy and DBS in the treatment of MS tremor, but no standardized outcome measures were used. Nonetheless, the data suggest that both thalamotomy and thalamic DBS are comparable procedures for tremor suppression and that adverse effects can occur with both procedures.

The prognostic value of serum S-100B protein in spontaneous subarachnoid haemorrhage

BACKGROUND

Despite the major progress in neurophysiological monitoring, there are still difficulties in the early identification and quantification of cerebral damage after a stroke. In this prospective study we examined the associations between serum S-100B protein, a serum marker of brain injury, and initial neurological-neuroimaging severity, secondary deterioration, external ventricular drainage (EVD: therapeutic intervention) and outcome in patients with subarachnoid haemorrhage (SAH).

METHOD

We recorded all pertinent clinical data of 52 patients with SAH and measured S-100B serum levels on admission and every 24 h for a maximum of 9 consecutive days. Mann-Whitney U-test and Kruskal Wallis analysis were employed to assess the association of S-100B levels with all variables of interest. Log-rank test was used to evaluate survival and Cox's proportional hazard regression analysis to define the significant predictors of survival rate.

FINDINGS

Admission S-100B was statistically significantly associated with initial neurological status, neuroimaging severity, and one-year outcome (p = 0.0002, 0.001, and 0.017, Kruskal Wallis analysis). Admission S-100B above 0.3 microg/L predicted unfavourable outcome (p < 0.0001, log rank test) and constituted an independent predictor of short-term survival (p = 0.035 Cox's proportional hazard regression analysis) with a hazard ratio of 2.2 (95% C.I.: 1.06-4.6) indicating a more than doubling of death probability. Secondary neurological deterioration associated with S-100B increase (p < 0.0001) and external ventricular drainage (EVD) with S-100B reduction (p = 0.003, Wilcoxon signed rank test).

CONCLUSIONS

Serum S-100B protein seems to be a useful biochemical indicator of neurological - neuroimaging severity, secondary deterioration, EVD (therapeutic intervention), and outcome in patients with SAH.

Serum S-100B as an Indicator of Early Postoperative Deterioration after Meningioma Surgery

Background: S-100B protein is an established serum marker of primary and secondary brain damage in head injury and stroke. Despite major progress in neurophysiologic monitoring, there are still difficulties in the early identification and quantification of evolving edema or trauma after craniotomy for tumor. In this study we aimed to correlate serum S-100B values with early postoperative neurologic course as well as late outcome in meningioma surgery.

Methods: We enrolled 50 consecutive patients who underwent meningioma resection. Serum S-100B was measured preoperatively and postcraniotomy for 7 consecutive days. Twenty-five patients (50%) developed immediate postoperative neurologic deterioration, and 15 (30%) had unfavorable 6-month outcomes. We used the Mann–Whitney U-test to assess the association of S-100B with all variables of interest. We used multiple logistic regression to search for the most significant predictor of postoperative deterioration.

Results: Increased S-100B was highly correlated with larger tumors, intraoperative difficulties, postcraniotomy acute deterioration, and long-term poor outcome. In addition, multiple logistic regression showed that age, sex, site, preoperative edema, history of meningioma resection, extent of resection, and histologic type did not correlate with postoperative increases in S-100B. Furthermore, patients with postoperative S-100B values &gt;0.4 μg/L had increased risk of deterioration (relative risk = 9.0; 95% confidence interval, 2.4–34; P &lt;0.0001) and of poor ultimate outcome (relative risk = 11; 95% confidence interval, 1.6–77; P = 0.002).

Conclusions: After meningioma excision, postcraniotomy increases in serum S-100B appear to be an early indicator of short-term postoperative neurologic deterioration and of a poor longer-term outcome.

Elevated Serum S-100B Protein as a Predictor of Failure to Short-Term Return to Work or Activities after Mild Head Injury

Protein S-100B is an established serum marker of primary and secondary brain damage and stroke. A group of patients after mild head injury (MHI) develop post-concussion symptoms that interfere with the ability in the short-term to return to work or undertake certain activities. The aim of this study was to examine the correlation of serum S-100B with short-term outcome after MHI. We studied 100 subjects who were referred to the Emergency Department (ED) after a MHI. All subjects had a GCS of 15 either with or without loss of consciousness (LOC) and/or post-traumatic amnesia (PTA). Serum S-100B was collected within 3 h from the injury and a value of > or = 0.15 microg/L was considered as abnormal. Subjects with other injuries, including scalp or cervical spine, were excluded, as well as those with alcohol/narcotic drug consumption or history of serious physical/mental illness. An independent observer measured the return to work/activities within one week. Thirty-two (32%) subjects had elevated S-100B. The failure to return to work/activities was significantly correlated with elevated S-100B: subjects with increased S-100B had a failure rate of 37.5% versus 4.9% of those with normal values (p = 0.0001). In MHI, the elevated S-100B seemed to correlate with an unfavorable short-term outcome. This might be useful in (1) selecting patients who need closer observation, hospitalization, and further investigations (such as CT scan or MRI), and (2) the prognosis of genuine post-concussion symptoms, that interfere with return to work or activities, versus other causes such as premorbid personality, labyrinthine dysfunction, whiplash syndrome, postinjury stress, occupational injury, litigation, and malingering.