Radioguided surgery in brain tumors with thallium-201.

RATIONALE: Malignant astrocytomas show thallium uptake with a high target-to-background ratio, allowing the use of radioguided surgery. METHOD: We report on 6 patients (3 men) diagnosed with malignant astrocytoma. All patients signed informed consent documents. Previous thallium-201 SPECT was performed, showing uptake in tumors. In the operating room we injected 37 MBq (1 mCi) of thallium-201 at the same time the craniotomy was performed. With the gamma probe we confirmed the tumor uptake, and a biopsy sample was taken. After conventional tumor resection, we scanned the surgical bed with the gamma probe. All areas of abnormal uptake were evaluated by the surgeon and, if possible, removed. RESULTS: In all patients the biopsy confirmed a high-grade astrocytoma. In all cases we found residual uptake in the surgical bed that was confirmed as residual tumor by pathologic examination. In 3 cases it was not possible to remove all the sites of pathologic uptake because critical areas were involved. In the other 3 patients, only background activity was found after the procedure. CONCLUSION: Radioguided surgery in brain tumors with thallium-201 is a complex technique and expertise in radioguided surgery and neuroimaging is needed, but we think that it is promising.

Multiple filum terminale hemangioblastomas symptomatic during pregnancy. Case report.

Hemangioblastomas are low-grade, highly vascular tumors commonly associated with von Hippel-Lindau (VHL) syndrome and most often appearing in the cerebellum. They very rarely occur in the spinal nerve roots, and an origin in the filum terminale is exceptional with no instances of multiple hemangioblastomas of the filum terminale reported in the literature. Because of their vascular nature, these lesions can enlarge and become symptomatic in the context of the changes that take place during pregnancy, as has been noted with cerebellar hemangioblastomas. In any case, the evolution of spinal hemangioblastomas during pregnancy is not well known given its rarity. The conjunction of both processes--that is, multiple hemangioblastomas arising in the filum terminale and pregnancy--is unique. The authors describe the case of a 41-year-old woman with multiple hemangioblastomas of the filum terminale and no other evidence of VHL syndrome, in whom pregnancy precipitated symptoms. The interruption of gestation led to a remission of the symptoms. The literature concerning filum terminale hemangioblastomas and pregnancy is also reviewed.

Severe intraoperative air embolism during convexity meningioma surgery in the supine position. Case report.

BACKGROUND: Acute venous air embolism (AE) is a well-known intraoperative complication of neurosurgical procedures, especially during surgical procedures performed in the sitting position, but it is a rare complication in the supine position. A case of a patient who developed an AE during a supratentorial craniotomy in the supine position is presented and the literature is reviewed. CASE DESCRIPTION: A 45-year-old man had a large left frontal convexity meningioma. He was operated upon and, during craniotomy in the supine position, suffered a massive episode of air embolism with severe respiratory and hemodynamic changes. The AE episode occurred while we were cutting the bone for the craniotomy before turning the bone flap. Because the patient was bleeding profusely, the bone flap was quickly removed to achieve hemostasis. Aspiration of irrigant into the cut bone surfaces through several venous diploic channels in the bone edges was observed. The procedure was terminated when hemostasis was achieved. The meningioma was successfully removed in a second operation. CONCLUSION: We think that our case should serve to warn the neurosurgical community about the risk of AE in supratentorial procedures in the supine or semisitting positions when preoperative radiological imaging studies show the presence of important venous channels in relation to the site of the tumor.