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.
Nícollas Nunes Rabelo, Bruno Braga Sisnando da Costa, Manoel Jacobsen Teixeira and Eberval Gadelha Figueiredo
Eberval Gadelha Figueiredo, Joseph M. Zabramski, Pushpa Deshmukh, Neil R. Crawford, Mark C. Preul and Robert F. Spetzler
The management of wide-necked, giant, or unsuccessfully coil-treated basilar apex aneurysms requires a wide exposure, for both working area and linear visualization of the basilar artery (BA). Cranial-based approaches, such as the transcavernous approach, have been proposed to deal with such aneurysms; whether abbreviated forms of this approach might provide similar exposure remains controversial. The authors examine this issue quantitatively.
Four alcohol-preserved cadaveric heads injected with pigmented silicone were prepared for bilateral dissection. After completing an orbitozygomatic craniotomy, the surgeons worked in a reverse direction, performing the transcavernous approach in five steps: 1) posterior clinoidectomy; 2) cavernous sinus opening; 3) anterior clinoidectomy; 4) cutting of the distal dural ring; and 5) cutting of the proximal dural ring.
Performing the complete transcavernous approach significantly increased the working area and linear exposure of the BA compared with abbreviated forms of the approach (p < 0.05). Opening the roof of the cavernous sinus significantly increased the working area compared with posterior clinoidectomy alone (p = 0.014); however, additional gains in exposure required completing the transcavernous approach. Resection of the anterior clinoid process combined with opening of only the distal dural ring did not significantly increase the working area or linear exposure of the BA.
The complete transcavernous approach significantly increases the working area and linear exposure of the BA compared with the more conservative forms of approach.
Jose Weber Vieira de Faria, Manoel Jacobsen Teixeira, Leonardo de Moura Sousa Júnior, Jose Pinhata Otoch and Eberval Gadelha Figueiredo
The authors sought to construct, implement, and evaluate an interactive and stereoscopic resource for teaching neuroanatomy, accessible from personal computers.
Forty fresh brains (80 hemispheres) were dissected. Images of areas of interest were captured using a manual turntable and processed and stored in a 5337-image database. Pedagogic evaluation was performed in 84 graduate medical students, divided into 3 groups: 1 (conventional method), 2 (interactive nonstereoscopic), and 3 (interactive and stereoscopic). The method was evaluated through a written theory test and a lab practicum.
Groups 2 and 3 showed the highest mean scores in pedagogic evaluations and differed significantly from Group 1 (p < 0.05). Group 2 did not differ statistically from Group 3 (p > 0.05). Size effects, measured as differences in scores before and after lectures, indicate the effectiveness of the method. ANOVA results showed significant difference (p < 0.05) between groups, and the Tukey test showed statistical differences between Group 1 and the other 2 groups (p < 0.05). No statistical differences between Groups 2 and 3 were found in the practicum. However, there were significant differences when Groups 2 and 3 were compared with Group 1 (p < 0.05).
The authors conclude that this method promoted further improvement in knowledge for students and fostered significantly higher learning when compared with traditional teaching resources.
Almir Ferreira de Andrade, Eberval Gadelha Figueiredo, Robson Luis Oliveira de Amorim, Wellingson S. Paiva, Guilherme Lepski and Manoel Jacobsen Teixeira
Rungsak Siwanuwatn, Pushpa Deshmukh, Eberval Gadelha Figueiredo, Neil R. Crawford, Robert F. Spetzler and Mark C. Preul
The authors quantitatively assessed the working areas and angles of attack associated with retrosigmoid (RS), combined petrosal (CP), and transcochlear (TC) craniotomies.
Four silicone-injected cadaveric heads were bilaterally dissected using three approaches progressing from the least to the most extensive. Working areas were determined using the Optotrak 3020 system on the upper and middle thirds of the petroclivus and brainstem. Angles of attack were studied using the Elekta SurgiScope at the Dorello canal and the origin of the anterior inferior cerebellar artery (AICA).
The TC approach provided significantly greater (p < 0.001) working areas at the petroclivus (755.6 ± 130.1 mm2) and brainstem (399.3 ± 68.2 mm2) than the CP (354.1 ± 60.3 and 289.7 ± 69.9 mm2) and RS approaches (292.4 ± 59.9, 177.2 ± 54.2 mm2, respectively). The brainstem working area associated with the CP approach was significantly larger (p < 0.001) than that associated with the RS route. There was no difference in the petroclival working area comparing the CP and RS approaches (p = 0.149). The horizontal and vertical angles of attack achieved using the TC approach were wider than those of the CP and RS at the Dorello canal and the origin of the AICA (p < 0.001).
The CP approach offers a more extensive working area than the RS for lesions involving the anterolateral surface of the brainstem, but not for petroclival lesions. The TC approach provides the widest corridor, improving the working area and angle of attack to both areas, but hearing must be sacrificed and the facial nerve is at risk.
Giselle Coelho, Eberval Gadelha Figueiredo, Nícollas Nunes Rabelo, Manoel Jacobsen Teixeira and Nelci Zanon
Craniosynostosis is a premature cranial suture junction and requires a craniectomy to decrease cranial compression and remodel the affected areas of the skull. However, mastering these neurosurgical procedures requires many years of supervised training. The use of surgical simulation can reduce the risk of intraoperative error. The authors propose a new instrument for neurosurgical education, which mixes reality with virtual and realistic simulation for repair of craniosynostosis (scaphocephaly type).
This study tested reality simulators with a synthetic thermo-retractile/thermosensitive rubber joined with different polymers. To validate the model, 18 experienced surgeons participated in this study using 3D videos developed using 3DS Max software. Renier’s “H” technique for craniosynostosis correction was applied during the simulation. All participants completed questionnaires to evaluate the simulator.
An expert surgical team approved the craniosynostosis reality and virtual simulators. More than 94% of participants found the simulator relevant, considering aspects such as weight, surgical positioning, dissection by planes, and cranial reconstruction. The consistency and material resistance were also approved on average by more than 60% of the surgeons.
The virtual simulator demands a high degree of effectiveness with 3D perception in anatomy and operative strategies in neurosurgical training. Physical and virtual simulation with mixed reality required psychomotor and cognitive abilities otherwise acquired only during practical surgical training with supervision.
Nícollas Nunes Rabelo, Manoel Jacobsen Teixeira, Robert F. Spetzler and Eberval Gadelha Figueiredo
Nícollas Nunes Rabelo, Renan Salomão Rodrigues, Arthur Araújo Massoud Salame, Paulo Henrique Braz-Silva, Manoel Jacobsen Teixeira and Eberval Gadelha Figueiredo
Eberval Gadelha Figueiredo, Manoel J. Teixeira, Robert F. Spetzler and Mark C. Preul