Andreu Gabarrós

Language and motor mapping during resection of brain arteriovenous malformations: indications, feasibility, and utility.

BACKGROUND:Microsurgical resection of arteriovenous malformations (AVMs) located in the language and motor cortex is associated with the risk of neurological deterioration, yet electrocortical stimulation mapping has not been widely used. OBJECTIVE:To demonstrate the usefulness of intraoperative mapping with language/motor AVMs. METHODS:During an 11-year period, mapping was used in 12 of 431 patients (2.8%) undergoing AVM resection (5 patients with language and 7 patients with motor AVMs). Language mapping was performed under awake anesthesia and motor mapping under general anesthesia. RESULTS:Identification of a functional cortex enabled its preservation in 11 patients (92%), guided dissection through overlying sulci down to the nidus in 3 patients (25%), and influenced the extent of resection in 4 patients (33%). Eight patients (67%) had complete resections. Four patients (33%) had incomplete resections, with circumferentially dissected and subtotally disconnected AVMs left in situ, attached to areas of eloquence and with preserved venous drainage. All were subsequently treated with radiosurgery. At follow-up, 6 patients recovered completely, 3 patients were neurologically improved, and 3 patients had new neurological deficits. CONCLUSION:Indications for intraoperative mapping include preoperative functional imaging that identifies the language/motor cortex adjacent to the AVM; larger AVMs with higher Spetzler-Martin grades; and patients presenting with unruptured AVMs without deficits. Mapping identified the functional cortex, promoted careful tissue handling, and preserved function. Mapping may guide dissection to AVMs beneath the cortical surface, and it may impact the decision to resect the AVM completely. More conservative, subtotal circumdissections followed by radiosurgery may be an alternative to observation or radiosurgery alone in patients with larger language/motor cortex AVMs.

Contralateral clipping of middle cerebral artery aneurysms: rationale, indications, and surgical technique.

BACKGROUND: Contralateral clipping of middle cerebral artery (MCA) aneurysms seems dangerous and ill advised but could become an important technique because of the prevalence of MCA aneurysms, the limitations of endovascular therapy, and increasing interest in less invasive techniques. OBJECTIVE: To define patient selection, surgical technique, and results with contralateral MCA aneurysm clipping. METHODS: Forty-two patients with bilateral MCA aneurysms were treated either in 1 stage with a single craniotomy and contralateral aneurysm clipping (group 1, 11 patients) or in 2 stages with bilateral craniotomy (group 2, 31 patients). Surgical technique consisted of ipsilateral sylvian fissure split, subfrontal dissection, contralateral sylvian fissure split, mobilization of medial orbital gyrus, and contralateral aneurysm clipping. RESULTS: Group 1 patients were older than group 2 patients (60.3 vs 55.4 years, respectively). Clinical presentation with subarachnoid hemorrhage was less common in group 1. Nine group 1 patients (82%) had left-sided craniotomies, and the ipsilateral aneurysm was larger than the contralateral aneurysm. All aneurysms were clipped without intraoperative complications (136 aneurysms). Mean neurosurgical charges were decreased by contralateral MCA aneurysm clipping:

Words are not enough: nonword repetition as an indicator of arcuate fasciculus integrity during brain tumor resection

39 297 in group 1 vs

Assessment of the Endoscopic Endonasal Transclival Approach for Surgical Clipping of Anterior Pontine Anterior-Inferior Cerebellar Artery Aneurysms

57 977 in group 2. CONCLUSION: Contralateral MCA aneurysm clipping can be viewed as an extreme microsurgical technique or as a less invasive technique that spares patients a second craniotomy in the management of bilateral aneurysms. This technique is acceptable in selected patients with contralateral aneurysms that are unruptured, have simple necks, project inferiorly or anteriorly, are associated with short M1 segments, and reside in older patients with sylvian fissures widened by brain atrophy. ABBREVIATIONS: ACA, anterior cerebral artery ICA, internal carotid artery MCA, middle cerebral artery mRS, modified Rankin Scale

Brain metastasis of carcinoma ex pleomorphic adenoma of the parotid gland: case report and review of the literature.

OBJECTIVE Subcortical electrical stimulation during brain surgery may allow localization of functionally crucial white matter fibers and thus tailoring of the tumor resection according to its functional limits. The arcuate fasciculus (AF) is a white matter bundle connecting frontal, temporal, and parietal cortical areas that is often disrupted by left brain lesions. It plays a critical role in several cognitive functions related to phonological processing, but current intraoperative monitoring methods do not yet allow mapping of this tract with sufficient precision. In the present study the authors aimed to test a new paradigm for the intraoperative monitoring of the AF. METHODS In this report, the authors studied 12 patients undergoing awake brain surgery for tumor resection with a related risk of AF damage. To preserve AF integrity and the cognitive processes sustained by this tract in the intraoperative context, the authors used real word repetition (WR) and nonword repetition (NWR) tasks as complements to standard picture naming. RESULTS Compared with the errors identified by WR or picture naming, the NWR task allowed the detection of subtle errors possibly related to AF alterations. Moreover, only 3 patients demonstrated phonological paraphasias in standard picture naming, and in 2 of these patients the paraphasias co-occurred with the total loss of WR and NWR ability. Before surgery, lesion volume predicted a patients NWR performance. CONCLUSIONS The authors suggest that monitoring NWR intraoperatively may complement the standard naming tasks and could permit better preservation of the important language production functions subserved by the AF.

Evaluation of the High-Frequency Monopolar Stimulation Technique for Mapping and Monitoring the Corticospinal Tract in Patients With Supratentorial Gliomas. A Proposal for Intraoperative Management Based on Neurophysiological Data Analysis in a Series of 92 Patients

OBJECTIVE Aneurysms of the anterior pontine segment of the anterior-inferior cerebellar artery (AICA) are uncommon. Their treatment is challenging because critical neurovascular structures are adjacent to it and the available surgical corridors are narrow and deep. Although endoscopic endonasal approaches are accepted for treating midline skull base lesions, their role in the treatment vascular lesions remains undefined. The present study is aimed to assess the anatomic feasibility of the endoscopic endonasal transclival (EET) approach for treating anterior pontine AICA aneurysms and compare it with the subtemporal anterior transpetrosal (SAT) approach. METHODS Twelve cadaveric specimens were prepared for surgical simulation. The AICAs were exposed using both EET and SAT approaches. Surgical window area and the length of the exposed artery were measured. The distance from the origin of the artery to the clip applied for proximal control was measured. The number of AICA perforators exposed and the anatomic features of each AICA were recorded. RESULTS The EET approach provided a wider surgical window area compared with the SAT (P < 0.001). More AICA perforators were visualized using the EET approach (P < 0.05). To obtain proximal control of the AICA, an aneurysm clip could be applied closer to the origin of AICA using EET (0.2 ± 0.42 mm) compared with SAT (6.26 ± 3.4 mm) (P < 0.001). CONCLUSION Clipping anterior pontine AICA aneurysms using the EET approach is feasible. Compared with SAT, the EET approach provides advantages in surgical window area, ensuring proximal control before aneurysm dissection, visualization of perforating branches, and better proximal control.

Radiologic Predictors for Extent of Resection in Pituitary Adenoma Surgery. A Single-Center Study

We present an extremely infrequent case of brain metastasis of a parotid tumor. To our knowledge, this is the second case reported of a brain metastasis of a malignant parotid tumor, carcinoma ex pleomorphic adenoma. Pleomorphic adenoma represents 60% of tumors of the parotid gland, and although it is a benign tumor, it can transform into carcinoma ex pleomorphic adenoma in 5% of cases, one of the most aggressive neoplasms of the salivary glands. We want to note the need for an accurate diagnostic. Thanks to aggressive surgical management, our patient survived more than 1½ years.

Delayed surgical site infection 2 years after cervical disk arthroplasty. Case report and literature review

BACKGROUND Intraoperative identification and preservation of the corticospinal tract is often necessary for glioma resection. OBJECTIVE To make a proposal for intraoperative management with the high-frequency monopolar stimulation technique for monitoring the corticospinal tract. METHODS Ninety-two patients operated on with the assistance of the high-frequency monopolar stimulation. Clinical and neurophysiological data have been related with the motor status at 3 months to establish prognostic factors of motor deterioration. RESULTS Twenty-one patients (22.8%) presented intraoperative alterations in motor-evoked potentials (MEPs). Twelve (13%) presented an increment in the MEP threshold ≥5 mA (no deficit at 3 months). Two (2.2%) presented an MEP amplitude reduction >50% (100% deficit at 3 months). Seven (7.6%) had an intraoperative MEP loss (80% deficit at 3 months). Subcortical stimulation was positive in 75 patients (81.5%). Eighty-five patients were available for the analysis at 3 months. Fourteen presented new deficits (16.5%). Among them, 5 presented a deficit in nonmonitored muscles (5.9%) and 1 presented a new deficit not detected intraoperatively. The combination of patients with preoperative motor deficits, MEP deterioration, or loss and intensity of subcortical stimulation ≤3 mA showed the highest sensitivity and specificity in the prediction of new deficits. CONCLUSIONS Persistent MEP loss or deterioration is associated with a high probability of new deficits. It seems recommendable to stop the subcortical resection before obtaining a subcortical MEP threshold at 3 mA especially in patients with preoperative motor deficits. A careful selection of muscles for the registration of MEPs is mandatory to avoid deficits in nonmonitored muscles.

Treatment of cavernous malformations in supratentorial eloquent areas: experience after 10 years of patient-tailored surgical protocol

BACKGROUND Preoperative radiologic evaluation of pituitary adenomas is essential. Despite the efforts made to determine the achieved resection grade after pituitary adenoma surgery, there is a high level of disagreement among all the available classifications and measurement methods used. Our study aimed to determine pituitary adenoma imaging features, easily obtained from preoperative magnetic resonance, which could be used as resection predictor variables. Second, we analyzed the usefulness of the ellipsoid method in pituitary adenoma volume determination. METHODS Two-hundred and ninety-four pituitary adenomas, which were surgically treated in our department, were retrospectively analyzed. Age, gender, surgical approach, hormonal status, greater tumor diameter, volume, cavernous sinus invasion, and extent of resection were evaluated. RESULTS One-hundred and forty-eight surgical procedures were conducted with a microsurgical transsphenoidal approach whereas 146 were conducted with an endoscopic endonasal approach. Gross total resection was achieved in 54.08% of cases. There were no significant differences in the extent of resection regarding the approach used, age, gender, or hormonal production by the tumor. Only Knosp grade (P < 0.001) and tumor volume (P < 0.05) had a statistically and independent significant relationship with the extent of resection. Furthermore, we found a high correlation between the calculated volume, using the ellipsoid method, and the volume measurement obtained with complex planimetry methods. CONCLUSIONS Pituitary adenoma volume and cavernous sinus invasion, graded with the Knosp scale, are 2 pituitary tumor features that, when used in combination, predict the complexity of the surgery and the difficulty of achieving gross total resection in pituitary adenoma surgery.

Functional approach using intraoperative brain mapping and neurophysiological monitoring for the surgical treatment of brain metastases in the central region.

Anterior cervical discectomy has a low non-mechanical complication rate. In our literature review, we found 7 cases of delayed surgical site infection. We report a case of cervical prevertebral abscess due to Propionibacterium acnes 2 years after discectomy and arthroplasty, with a beta-2-transferrin false positive test as a complementary highlighted finding. We discuss the diagnosis and etiology of this rare delayed infectious complication.