ABSTRACT
Delayed ischemic neurologic deficit (DIND) is the main preventable cause of poor outcomes in aneurysmal subarachnoid hemorrhage (SAH) patients. Of 50% of survivors from a SAH, approximately 30% of patients will present clinical vasospasm (VS). The cornerstone of the DIND management comprises prevention and early identification. Several diagnostic methods have been proposed differing in efficacy, invasiveness, and costs. Serial neurological examination is the most reliable method to detect a new neurological deficit. On the other hand, comatose patients require advanced monitoring methods which identify changes in the microcirculatory environment, brain autoregulation, and spreading depolarization. Multimodality monitoring with continuous electroencephalography, microdialysis, and intracranial pressure monitoring represents altogether the current state-of-art technology for the intensive care of SAH patients. Moreover, advances in genetic biomarkers to predict clinical VS have shown consistent accuracy which may in the near future allow the early prediction of DIND through a simple blood test. Several clinical trials have tested drugs with theoretical effects on DIND prevention or treatment. Nevertheless, nimodipine remains the Holy Grail in the prevention of clinical VS. Among rescue therapies, the endovascular treatment through intra-arterial vasodilator (verapamil or nicardipine) infusion is the most employed method for DIND reversal; however, there is no good quality evidence comparing results of intra-arterial infusion of vasodilators versus balloon angioplasty. Although we have addressed the most refined technology in the management of SAH and DIND, the clinical experience and strict follow-up in neurointensive care will be determinant for favorable long-term outcomes.
ABSTRACT
OBJECTIVE: The brainstem is a compact, delicate structure. The surgeon must have good anatomical knowledge of the safe entry points to safely resect intrinsic lesions. Lesions located at the lateral midbrain surface are better approached through the lateral mesencephalic sulcus (LMS). The goal of this study was to compare the surgical exposure to the LMS provided by the subtemporal (ST) approach and the paramedian and extreme-lateral variants of the supracerebellar infratentorial (SCIT) approach. METHODS: These 3 approaches were used in 10 cadaveric heads. The authors performed measurements of predetermined points by using a neuronavigation system. Areas of microsurgical exposure and angles of the approaches were determined. Statistical analysis was performed to identify significant differences in the respective exposures. RESULTS: The surgical exposure was similar for the different approaches-369.8 ± 70.1 mm2 for the ST; 341.2 ± 71.2 mm2 for the SCIT paramedian variant; and 312.0 ± 79.3 mm2 for the SCIT extreme-lateral variant (p = 0.13). However, the vertical angular exposure was 16.3° ± 3.6° for the ST, 19.4° ± 3.4° for the SCIT paramedian variant, and 25.1° ± 3.3° for the SCIT extreme-lateral variant craniotomy (p < 0.001). The horizontal angular exposure was 45.2° ± 6.3° for the ST, 35.6° ± 2.9° for the SCIT paramedian variant, and 45.5° ± 6.6° for the SCIT extreme-lateral variant opening, presenting no difference between the ST and extreme-lateral variant (p = 0.92), but both were superior to the paramedian variant (p < 0.001). Data are expressed as the mean ± SD. CONCLUSIONS: The extreme-lateral SCIT approach had the smaller area of surgical exposure; however, these differences were not statistically significant. The extreme-lateral SCIT approach presented a wider vertical and horizontal angle to the LMS compared to the other craniotomies. Also, it provides a 90° trajectory to the sulcus that facilitates the intraoperative microsurgical technique.
ABSTRACT
OBJECTIVE: To describe and compare surgical exposure through microsurgical cadaveric dissection of the intercollicular region afforded by the median, paramedian, and extreme-lateral supracerebellar infratentorial (SCIT) approaches. METHODS: Ten cadaveric heads were dissected using SCIT variant approaches. A neuronavigation system was used to determine tridimensional coordinates for the intercollicular zone in each route. The areas of surgical and angular exposure were evaluated and determined by software analysis for each specimen. RESULTS: The median surgical exposure was similar for the different craniotomies: 282.9 ± 72.4 mm2 for the median, 341.2 ± 71.2 mm2 for the paramedian, and 312.0 ± 79.3 mm2 for the extreme-lateral (P = 0.33). The vertical angular exposure to the center of the intercollicular safe entry zone was also similar between the approaches (P = 0.92). On the other hand, the horizontal angular exposure was significantly wider for the median approach (P < 0.001). CONCLUSIONS: All the SCIT approaches warrant a safe route to the quadrigeminal plate. Among the different variants, the median approach had the smallest median surgical area exposure but presented superior results to access the intercollicular safe entry zone.
Subject(s)
Cerebellum/surgery , Craniotomy , Neuronavigation , Neurosurgical Procedures , Cadaver , Craniotomy/methods , Dissection/methods , Humans , Microsurgery/adverse effects , Microsurgery/methods , Neuronavigation/adverse effects , Neuronavigation/methods , Neurosurgical Procedures/methodsABSTRACT
A história natural dos schwanomas vestibulares ainda não é totalmente conhecida, mas a maioria destas lesões tende ao crescimento lento, algumas vezes sem qualquer manifestação clínica durante toda a vida do indivíduo, sendo em ocasiões achado de autópsias. Consideráveis avanços no conhecimento da anatomia da base do crânio, assim como os recursos tecnológicos de eletrofisiologia, como a monitorização intra-operatória têm possibilitado índices crescentes de preservação funcional do nervo facial e da audição. Devido a isso, a ressecção cirúrgica completa da lesão permanece sendo o tratamento de escolha quando possível. No entanto, em casos selecionados, o tratamento conservador é uma opção muito bem aceita, desde que haja um seguimento radiológico estrito. Opções terapêuticas como a radiocirurgia são também válidas e devem sempre ser consideradas no armamentarium neurocirúrgico. Novos estudos com quimioterápicos (bevacizumab) também podem mudar a conduta referente às indicações cirúrgicas. Neste artigo, apresentamos o caso de um paciente sexo feminino, de 35 anos de idade, com schwanoma vestibular à direita, intracanalicular, diagnosticado em 2006 com rápido crescimento volumétrico da lesão verificado em exame de seguimento realizado cinco anos após o diagnóstico inicial. É realizada também uma revisão da literatura mundial, envolvendo os padrões de crescimento do schwanoma vestibular, bem como opções de tratamento e seguimento lesional.
