Barbara Zarino

Role of Intraoperative Neurophysiologic Monitoring in the Resection of Thalamic Astrocytomas

BACKGROUND The thalamus is a deep-seated and crucial structure for the sensorimotor system. It has been long considered a surgically inaccessible area because of the morbidity associated with surgical resections. Astrocytomas of the thalamus are usually treated with bioptic procedures followed by adjuvant treatments. Intraoperative neurophysiologic monitoring (IONM) allows safe and satisfactory resections of lobar gliomas, but few data are available for thalamic lesions. The aim of this study was to review the outcome of a small series of patients with thalamic astrocytomas that were treated with surgical resection with the aid of IONM. METHODS Surgical resection with IONM was performed in 5 patients with thalamic astrocytomas (1 grade I, 1 grade II, 2 grade III, 1 grade IV). Two astrocytomas were in the dominant hemisphere. Preoperative and postoperative neuropsychological assessments were performed in 3 patients. IONM was tailored to the individual patient and consisted of transcranial motor evoked potential monitoring, cortical motor evoked potential monitoring, somatosensory evoked potential monitoring, direct electrical stimulation, electroencephalography, and electrocorticography. RESULTS None of the patients experienced permanent motor deficits; 2 patients had a transient hemiparesis requiring rehabilitation; 1 patient had a transient aphasia, and 1 patient had permanent aphasia. None of the patients had intraoperative seizures, but 1 patient experienced postoperative transient status epilepticus. The extent of resection on postoperative volumetric magnetic resonance imaging was >70% in all cases. CONCLUSIONS Surgical resection of thalamic astrocytomas appeared to be effective and relatively safe when guided by IONM. Larger series of patients are required to confirm these preliminary data.

Supplementary Tests in Idiopathic Normal Pressure Hydrocephalus: A Single-Center Experience with a Combined Lumbar Infusion Test and Tap Test

BACKGROUND The lumbar infusion test (LIT) and tap test (TT) have previously been described for the diagnosis and selection of appropriate surgical candidates in idiopathic normal pressure hydrocephalus (iNPH). METHODS We retrospectively reviewed 81 consecutive patients with a clinical diagnosis of iNPH selected for supplementary testing. Clinical evaluation was scored with the Japanese Grading Scale for Normal Pressure Hydrocephalus, the Global Deterioration Score, and the modified Rankin Scale (mRS). The test protocol included a cerebrospinal fluid pressure monitoring (PMi), an LIT, and a TT. Patients were selected for surgery if outflow resistance was ≥14 mm Hg/mL/minute or if a clinical improvement was recorded after TT. RESULTS Sixty-eight patients were selected for ventriculoperitoneal shunting; 72.8% had a positive PMi or LIT, 74.1% had a positive TT, and 63.0% were positive to both tests. Complications were all transient. Clinical evaluation at 12 months after shunting showed a global improvement in 60 patients (88.2%). Overall, 75.0% of patients had no significant disability (mRS score, 1 and 2), 20.6% had an mRS score of 3 or 4, and 4.4% had severe disability after surgery. The positive predictive value of PMi/LIT, TT, or both combined was similar (89.8, 90.0, and 88.2%); however, 21.7% of patients who improved after surgery were selected with either a positive LIT or TT alone. CONCLUSIONS LIT and TT are complementary and they can easily be combined in sequence with a low complication rate and high probability of selecting patients with iNPH who may benefit from ventriculoperitoneal shunt surgery.

Selection of Elderly Meningioma Patients for Surgery Using a Clinical-Radiological Grading System as a Predictor of Outcome

Based on a retrospective study, in a previous report we developed a grading system, called ‘Clinical Radiological Grading System’ (CRGS), in order to standardise surgical indications in patients older than 70 years affected by intracranial meningiomas. Various prognostic factors were taken into consideration: clinical conditions, comorbidities, neurological status, size and size of the lesion and peritumoral edema. We then performed a prospective cross-sectional study including 90 consecutively recruited patients (from 1990 to 2000), 70 years of age or older, affected by meningiomas in whom the decision whether to operate was based on the CRGS score. Our findings showed that patients with a score lower than 10 had a poor prognosis regardless of surgical treatment, those with a score between 10 and 12 had a prognosis positively influenced by surgery, and those with a score higher than 12 had a good prognosis regardless of surgical treatment. A further validation of our scale has been made in a second prospective study, which is discussed in the present chapter. We also analyzed similar studies performed by other authors and compare our grading system to alternative scores which have been created afterwards.