Tyler S. Cole and Robert F. Spetzler
Nícollas Nunes Rabelo, Manoel Jacobsen Teixeira, Robert F. Spetzler and Eberval Gadelha Figueiredo
Tim E. Darsaut and Jean Raymond
M. Yashar S. Kalani, Robert F. Spetzler, Rudolf Fahlbusch and James K. Liu
M. Yashar S. Kalani, Kaan Yağmurlu, Nikolay L. Martirosyan and Robert F. Spetzler
The lateral supracerebellar infratentorial (SCIT) approach provides advantageous access to lesions located in the lateral mesencephalon and mesencephalopontine junction. For lesions that abut the pial surface, a direct approach is ideal and well tolerated. For deep-seated lesions, the lateral mesencephalic sulcus (LMS) can be used to access lesions with minimal morbidity to the patient. This video demonstrates the use of the SCIT approach via the LMS to remove a cavernous malformation at the level of the mesencephalopontine junction. The use of somatosensory and motor evoked potential monitoring and intraoperative neuronavigation is essential for optimizing patient outcomes. Meticulous, multilayered closure is critical for optimal results in the posterior fossa. For optimal patient outcomes, approach selection for deep-seated lesions should combine the two-point method with safe entry zones. At follow-up, the patient had persistent sensory changes but was otherwise neurologically intact.
The video can be found here: https://youtu.be/bHFEZhG8dHw.
M. Yashar S. Kalani, Kaan Yağmurlu, Nikolay L. Martirosyan and Robert F. Spetzler
Dorsal pons lesions at the facial colliculus level can be accessed with a suboccipital telovelar (SOTV) approach using the superior fovea safe entry zone. Opening the telovelar junction allows visualization of the dorsal pons and lateral entry at the level of the fourth ventricle floor. Typically, a lateral entry into the floor of the fourth ventricle is better tolerated than a midline opening. This video demonstrates the use of the SOTV approach to remove a cavernous malformation at the level of the facial colliculus. This case is particularly interesting because of a large venous anomaly and several telangiectasias in the pons. Dissections in the video are reproduced with permission from the Rhoton Collection (http://rhoton.ineurodb.org).
The video can be found here: https://youtu.be/LqzCfN2J3lY.
Daniel Dutra Cavalcanti, Bárbara Albuquerque Morais, Eberval Gadelha Figueiredo, Robert F. Spetzler and Mark C. Preul
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.
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.
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.
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.
Eberval Gadelha Figueiredo, Saul Almeida da Silva, Manoel Jacobsen Teixeira, Evgenii Belykh, Alessandro Carotenuto, Leandro Borba Moreira, Robert F. Spetzler, T. Forcht Dagi and Mark C. Preul
Fedor Krause, the father of German neurosurgery, traveled to Latin America twice in the final years of his career (in 1920 and 1922). The associations and motivations for his travels to South America and his work there have not been well chronicled. In this paper, based on a review of historical official documents and publications, the authors describe Krause’s activities in South America (focusing on Brazil) within the context of the Germanism doctrine and, most importantly, the professional enjoyment Krause reaped from his trips as well as his lasting influence on neurosurgery in South America. Fedor Krause’s visits to Brazil occurred soon after World War I, when Germany sought to reestablish economic, political, cultural, and scientific power and influence. Science, particularly medicine, had been chosen as a field capable of meeting these needs. The advanced German system of academic organization and instruction, which included connections and collaborations with industry, was an optimal means to reestablish the economic viability of not only Germany but also Brazil. Krause, as a de facto ambassador, helped rebuild the German image and reconstruct diplomatic relations between Germany and Brazil. Krause’s interactions during his visits helped put Brazilian neurosurgery on a firm foundation, and he left an indelible legacy of advancing professionalism and specialization in neurosurgery in Brazil.
Peyton L. Nisson, Salman A. Fard, Christina M. Walter, Cameron M. Johnstone, Michael A. Mooney, Ali Tayebi Meybodi, Michael Lang, Helen Kim, Heidi Jahnke, Denise J. Roe, Travis M. Dumont, G. Michael Lemole Jr., Robert F. Spetzler and Michael T. Lawton
The objective of this study was to evaluate the existing Spetzler-Martin (SM), Spetzler-Ponce (SP), and Lawton-Young (LY) grading systems for cerebellar arteriovenous malformations (AVMs) and to propose a new grading system to estimate the risks associated with these lesions.
Data for patients with cerebellar AVMs treated microsurgically in two tertiary medical centers were retrospectively reviewed. Data from patients at institution 1 were collected from September 1999 to February 2013, and at institution 2 from October 2008 to October 2015. Patient outcomes were classified as favorable (modified Rankin Scale [mRS] score 0–2) or poor (mRS score 3–6) at the time of discharge. Using chi-square and logistic regression analysis, variables associated with poor outcomes were assigned risk points to design the proposed grading system. The proposed system included neurological status prior to treatment (poor, +2 points), emergency surgery (+1 point), age > 60 years (+1 point), and deep venous drainage (deep, +1 point). Risk point totals of 0–1 comprised grade 1, 2–3 grade 2, and 4–5 grade 3.
A total of 125 cerebellar AVMs of 1328 brain AVMs were reviewed in 125 patients, 120 of which were treated microsurgically and included in the study. With our proposed grading system, we found poor outcomes differed significantly between each grade (p < 0.001), while with the SM, SP, and LY grading systems they did not (p = 0.22, p = 0.25, and p = 1, respectively). Logistic regression revealed grade 2 had 3.3 times the risk of experiencing a poor outcome (p = 0.008), while grade 3 had 9.9 times the risk (p < 0.001). The proposed grading system demonstrated a superior level of predictive accuracy (area under the receiver operating characteristic curve [AUROC] of 0.72) compared with the SM, SP, and LY grading systems (AUROC of 0.61, 0.57, and 0.51, respectively).
The authors propose a novel grading system for cerebellar AVMs based on emergency surgery, venous drainage, preoperative neurological status, and age that provides a superior prognostication power than the formerly proposed SM, SP, and LY grading systems. This grading system is clinically predictive of patient outcomes and can be used to better guide vascular neurosurgeons in clinical decision-making.