Eduardo Carvalhal Ribas

Surgical Anatomy of Microneurosurgical Sulcal Key Points

OBJECTIVE: The brain sulci constitute the main microanatomic delimiting landmarks and surgical corridors of modern microneurosurgery. Because of the frequent difficulty in intraoperatively localizing and visually identifying the brain sulci with assurance, the main purpose of this study was to establish cortical/sulcal key points of primary microneurosurgical importance to provide a sulcal anatomic framework for the placement of craniotomies and to facilitate the main sulci intraoperative identification. METHODS: The study was performed through the evaluation of 32 formalin-fixed cerebral hemispheres of 16 adult cadavers, which had been removed from the skulls after the introduction of plastic catheters through properly positioned burr holes necessary for the evaluation of cranial–cerebral relationships. Three-dimensional anatomic and surgical images are displayed to illustrate the use of sulcal key points. RESULTS: The points studied were the anterior sylvian point, the inferior rolandic point, the intersection of the inferior frontal sulcus with the precentral sulcus, the intersection of the superior frontal sulcus with the precentral sulcus, the superior rolandic point, the intersection of the intraparietal sulcus with the postcentral sulcus, the superior point of the parieto-occipital sulcus, the euryon (the craniometric point that corresponds to the center of the parietal tuberosity), the posterior point of the superior temporal sulcus, and the opisthocranion, which corresponds to the most prominent point of the occipital bossa. These points presented regular neural and cranial–cerebral relationships and can be considered consistent microsurgical cortical key points. CONCLUSION: These sulcal and gyral key points can be particularly useful for initial intraoperative sulci identification and dissection. Together, they compose a framework that can help in the understanding of hemispheric lesion localization, in the placement of supratentorial craniotomies, as landmarks for the transsulcal approaches to periventricular and intraventricular lesions, and in orienting the anatomic removal of gyral sectors that contain infiltrative tumors.

Role of endoscopic third ventriculostomy and ventriculoperitoneal shunt in idiopathic normal pressure hydrocephalus: preliminary results of a randomized clinical trial.

BACKGROUND Currently, the most common treatment for idiopathic normal pressure hydrocephalus (INPH) is a ventriculoperitoneal shunt (VPS), generally with programmable valve implantation. Endoscopic third ventriculostomy (ETV) is another treatment option, and it does not require prosthesis implantation. OBJECTIVE To compare the functional neurological outcome in patients after 12 months of treatment with INPH by using 2 different techniques: ETV or VPS. METHODS Randomized, parallel, open-label trial involving the study of 42 patients with INPH and a positive response to the tap test, from January 2009 to January 2012. ETV was performed with a rigid endoscope with a 30° lens (Minop, Aesculap), and VPS was performed with a fixed-pressure valve (PS Medical, Medtronic). The outcome was assessed 12 months after surgery. The neurological function outcomes were based on the results of 6 clinical scales: mini-mental, Berg balance, dynamic gait index, functional independence measure, timed up and go, and normal pressure hydrocephalus. RESULTS There was a statistically significant difference between the 2 groups after 12 months of follow-ups, and the VPS group showed better improvement results (ETV = 50%, VPS = 76.9%). CONCLUSION Compared with ETV, VPS is a superior method because it had better functional neurological outcomes 12 months after surgery.

Use of low intensity laser treatment in neuropathic pain refractory to clinical treatment in amputation stumps

Debilitating stump pain following amputation surgery is a major problem when it affects the patient’s quality of life, often making the patient totally dependent on others for their day-to-day care. Attempts have been made to treat those patients through pharmacological, psychological, and physical therapies, but in many cases these fail to relieve the pain. This article focuses on three patients with chronic, intense, and debilitating stump pain who were previously treated with pain medications, but with little success. These patients underwent nine sessions of low-intensity laser therapy (LILT) to the stump – this is a new treatment that has been used to treat other pain disorders. All patients reported a decrease in the intensity of their pain and increased ability to perform daily living activities during a 4-month follow-up.

Three-dimensional digital projection in neurosurgical education: technical note.

Three-dimensional images have become an important tool in teaching surgical anatomy, and its didactic power is enhanced when combined with 3D surgical images and videos. This paper describes the method used by the last author (G.C.R.) since 2002 to project 3D anatomical and surgical images using a computer source. Projecting 3D images requires the superposition of 2 similar but slightly different images of the same object. The set of images, one mimicking the view of the left eye and the other mimicking the view of the right eye, constitute the stereoscopic pair and can be processed using anaglyphic or horizontal-vertical polarization of light for individual use or presentation to larger audiences. Classically, 3D projection could be obtained by using a double set of slides, projected through 2 slide projectors, each of them equipped with complementary filters, shooting over a medium that keeps light polarized (a silver screen) and having the audience wear appropriate glasses. More recently, a digital method of 3D projection has been perfected. In this method, a personal computer is used as the source of the images, which are arranged in a Microsoft PowerPoint presentation. A beam splitter device is used to connect the computer source to 2 digital, portable projectors. Filters, a silver screen, and glasses are used, similar to the classic method. Among other advantages, this method brings flexibility to 3D presentations by allowing the combination of 3D anatomical and surgical still images and videos. It eliminates the need for using film and film developing, lowering the costs of the process. In using small, powerful digital projectors, this method substitutes for the previous technology, without incurring a loss of quality, and enhances portability.

Head positioning for anterior circulation aneurysms microsurgery

OBJECTIVE To study the ideal patients head positioning for the anterior circulation aneurysms microsurgery. METHOD We divided the study in two parts. Firstly, 10 fresh cadaveric heads were positioned and dissected in order to ideally expose the anterior circulation aneurysm sites. Afterwards, 110 patients were submitted to anterior circulation aneurysms microsurgery. During the surgery, the patients head was positioned accordingly to the aneurysm location and the results from the cadaveric study. The effectiveness of the position was noted. RESULTS We could determine mainly two patterns for head positioning for the anterior circulation aneurysms. CONCLUSION The best surgical exposure is related to specific head positions. The proper angle of microscopic view may minimize neurovascular injury and brain retraction.

Intraoperative ultrasonography for presumed brain metastases: a case series study

UNLABELLED Brain metastases (BM) are one of the most common intracranial tumors and surgical treatment can improve both the functional outcomes and patient survival, particularly when systemic disease is controlled. Image-guided BM resection using intraoperative exams, such as intraoperative ultrasound (IOUS), can lead to better surgical results. METHODS To evaluate the use of IOUS for BM resection, 20 consecutive patients were operated using IOUS to locate tumors, identify their anatomical relationships and surgical cavity after resection. Technical difficulties, complications, recurrence and survival rates were noted. RESULTS IOUS proved effective for locating, determining borders and defining the anatomical relationships of BM, as well as to identify incomplete tumor resection. No complications related to IOUS were seen. CONCLUSION IOUS is a practical supporting method for the resection of BM, but further studies comparing this method with other intraoperative exams are needed to evaluate its actual contribution and reliability.

Trends in the mortality of non-traumatic subarachnoid hemorrhage in Colombia: a 10-year analysis of a nationwide registry

OBJECTIVE To assess trends in mortality from 1999 to 2008 resulting from non-traumatic subarachnoid hemorrhage (SAH) in the Colombian population. METHOD This population-based study analyzed all deaths by assuming a Poisson model. RESULTS Subarachnoid hemorrhage-related deaths showed a statistically significant increase of 1.6% per year (p<0.001). The age-standardized analysis demonstrated an increased mortality trend of 3.3% per year (p<0.001) in people older than 70 years, but a decreased mortality trend in people younger than 50. It remained stable in patients 50-69 years old. CONCLUSION The overall SAH-related mortality rate in Colombia has increased because increased mortality among the elderly has been counterbalanced by reduced mortality rates in younger age groups. These disparities may reflect epidemiologic transition, treatment inequities, or a less favorable comorbid profile.

Microsurgical Approaches to the Ambient Cistern Region: An Anatomic and Qualitative Study.

OBJECTIVE We used microscopy to conduct qualitative and quantitative analysis of 4 surgical approaches commonly used in the surgery of the ambient cistern: infratentorial supracerebellar (SC), occipital interhemispheric, subtemporal (ST), and transchoroidal (TC). In addition, we performed a parahippocampal gyrus resection in the ST context. METHODS Each approach was performed in 3 cadaveric heads (6 sides). After the microscopic anatomic dissection, the parahippocampal gyrus was resected through an ST approach. The qualitative analysis was based on anatomic observation and the quantitative analysis was based on the linear exposure of vascular structures and the area of exposure of the ambient cistern region. RESULTS The ST approach provided good exposure of the inferior portion of the cistern and of the proximal segments of the posterior cerebral artery. After the resection of the parahippocampal gyrus, the area of exposure improved in all components, especially the superior area. A TC approach provided the best exposure of the superior area compared with the other approaches. The posterolateral approaches (SC/occipital interhemispheric) to the ambient cistern region provided similar exposure of anatomic structures. There was a significant difference (P < 0.05) in linear exposure of the posterior cerebral artery when comparing the ST/TC and ST/SC approaches. CONCLUSIONS This study has demonstrated that surgical approaches expose dissimilarly the different regions of the ambient cistern and an approach should be selected based on the specific need of anatomic exposure.

The Role of Endoscopic Assistance in Ambient Cistern Surgery: Analysis of Four Surgical Approaches.

OBJECTIVE We used microscopy with endoscopic assistance to conduct an objective analysis of 4 surgical approaches commonly used in the surgery of the ambient cistern: infratentorial supracerebellar (SC), occipital interhemispheric (OI), subtemporal (ST), and transchoroideal (TC). In addition, we performed a parahippocampalis gyrus resection in the ST context. METHODS Each approach (SC, OI, ST, TC) was performed on 3 cadaveric heads (6 sides). After the microscopic anatomic dissection, the 30-degree endoscope was used to explore the exposure. The parahippocampalis gyrus was resected through an ST approach and the exposure was evaluated. The quantitative analysis was based on linear exposure of the vascular structures (linear exposure), such as the posterior choroidal artery (PChA), the P2 and P3 segments of the posterior cerebral artery (PCA) with their branches, the basal vein of Rosenthal, and the area of exposure of the ambient cistern region (area of exposure) limited by points on its superior, mesial, and anterior walls. In all cases, a P value of less than 0.05 was considered significant. RESULTS There was a significant difference (P < 0.05) in linear exposure of the PCA and medial PChA between microsurgery and endoscopic assistance using the ST approach. This approach also improved the medial, superior, and total exposure of the ambient cistern region. CONCLUSIONS This study demonstrates that endoscope assistance improved exposure of the ambient cistern region when using the ST approach. Endoscopic assistance provided similar surgical exposure compared with ST associated with parahippocampalis resection.

Survival score scales of patients operated with spinal metastases: retrospective application in a Brazilian population

Spinal cord epidural metastasis (SEM) is a common complication of systemic cancer. Predicting these patients survival is a key factor to select the proper treatment modality, but the three most used score scales to predict their survival (Tokuhashi revised score, Tomita score and Bauer modified score) were designed in single institutions and their reliability to predict correctly the patients survival were first tested only in those specific populations. This prognostication issue is addressed in this article, evaluating retrospectively the survival of 17 patients with SEM from a Brazilian general hospital with these score scales. Our results show that the actual survival of those patients were worse than the predicted of all three score scales, suggesting that differences between the different populations might have affected their reliability and alert that their usage as a major factor to select the most appropriate treatment have to be done with caution.