Thermocoagulation of the Ictal Onset Zone Using SEEG (Thermo-SEEG)

Stereo-EEG (SEEG)-guided radiofrequency thermocoagulation (thermo-SEEG), is a stereotactic lesioning procedure in which the SEEG electrodes are used to deliver a radiofrequency current. This technique offers drug-resistant epileptic patients undergoing phase 2 investigations the possibility to benefit from lesions of the ictal onset zone without any additional invasive stereotactic procedure. A SEEG recording site can be considered eligible for thermo-SEEG if bipolar recordings through two adjacent contacts of the same electrode, located in cortical grey matter, show evidence of either spike-wave discharges or low-amplitude fast pattern at the onset of seizures. Electrical stimulations are systematically performed during video-SEEG recording sessions to avoid possible side-effects of a lesion. After 1-year follow-up, 45.6% of patients show greater than 50% improvement in terms of seizure frequency and 11.9% are seizure-free. Moreover, thermo-SEEG is safer than conventional surgery, with only a 3.2% rate of side-effects, which are almost always transient, including the expected ones.

Stereotactic radiosurgery for secreting pituitary tumors

Radiosurgery (SRS) or Stereotactic Radiotherapy (SRT) is a standard procedure as second-line treatment in patients with pituitary adenoma, when cure with the initial surgical and/or hormonal treatment is not possible. When compared to conventional Radiotherapy (RT), the stereotactic procedure shows a reduction of risks especially in visual and pituitary alterations. The prognosis of this type of intervention in the long-term control of tumor growth is excellent in 95 to 100% of the cases. In patients who have secreting tumors, reduction or normalization of elevated hormone levels are observed (40 to 92%). In general, the latency time is more than16 months and is dependent on the dose and the number of fractions. The best results are observed in Acromegaly, followed by Cushing`s Disease and Prolactinoma.

An Analysis of the Respective Risks of Hematoma Formation in 361 Consecutive Morphological and Functional Stereotactic Procedures

ABSTRACT OBJECTIVE The risk of hematoma formation in stereotactic procedures is generally considered to range between 1 and 4%, and it has been speculated that morphological procedures may have a higher risk of bleeding than functional procedures. METHODS Between 1989 and 1999, all patients who underwent a stereotactic procedure performed by the same surgeon were enrolled sequentially onto the study. All patients had normal preoperative prothrombin time, partial thromboplastin time, and platelet count. High-resolution computed tomography or magnetic resonance imaging with a 1.5-T machine were used for the target definition. None of the patients had an angiogram before surgery. RESULTS A total of 361 procedures was performed comprising 175 morphological procedures (139 biopsies, 18 lesion evacuations [cysts, abscesses, and hematomas], and 18 drain implantations) and 186 functional procedures (137 lesions [thalamotomy or pallidotomy], 47 deep brain electrode implantations, and two physiological explorations without lesions or implantations). There were no infections or seizures in either group. Three hematomas (1.7%) occurred in the morphological group, two of them in inflammatory lesions in immunocompromised patients (one death) and one in a pineal tumor. Three hematomas (1.6%) occurred in the functional group (no mortality). There was no statistically significant difference (P > 0.05; Fisher's exact test) in the risk of hematoma formation between morphological and functional stereotactic procedures. The morbidity and mortality related to bleeding also were not statistically different (P > 0.05; Fisher's exact test) between these two groups. CONCLUSION In this series, the risk of bleeding was not higher for morphological procedures than for functional procedures. This suggests that the risk of bleeding for stereotactic procedures is related more to the patient than to the type of procedure performed. Our study confirms an overall risk of bleeding of 1.7% for any type of stereotactic procedure, resulting in a mortality of 0.3% and a morbidity of 1.4%.