Rungsak Siwanuwatn

Quantitative anatomic study of three surgical approaches to the anterior communicating artery complex.

OBJECTIVE: To compare the angles of approach and area of exposure to the anterior communicating artery (AComA) complex associated with pterional (PT), orbitopterional (OPT), and orbitozygomatic (OZ) craniotomies before and after gyrus rectus resection. METHODS: PT, OPT, and OZ craniotomies were performed on both sides of four heads, and the angles of approach and area of exposure to the AComA complex were measured before and after resection of the gyrus rectus. RESULTS: The vertical angle of approach increased significantly among the PT and OPT (P = 0.001), PT and OZ (P = 0.001), and OPT and OZ approaches (P = 0.005). The horizontal angle of approach was significantly larger between the PT to OPT (P = 0.001) and PT to OZ (P = 0.001) approaches but not between the OPT and OZ approaches (P = 0.757). After gyrus rectus resection, the vertical and horizontal angles of approach increased significantly for the PT approach but not for the OPT and OZ approaches. The area of exposure to the AComA complex increased progressively from the PT to OPT to OZ approach but did not reach statistical significance (P = 0.124). Resection of the gyrus rectus resulted in significant relative gains in the area of exposure for the PT (P = 0.01) and OPT (P = 0.04) approaches but not for the OZ approach (P = 0.88). CONCLUSION: The vertical and horizontal angles of approach to the AComA complex are significantly larger for the OPT and OZ approaches compared with the PT approach. Use of the OZ approach may decrease the need for frontal lobe retraction and resection of the gyrus rectus.

MICROSURGICAL ANATOMY AND QUANTITATIVE ANALYSIS OF THE TRANSTEMPORAL-TRANSCHOROIDAL FISSURE APPROACH TO THE AMBIENT CISTERN

OBJECTIVE: Surgical approaches to ambient cistern lesions are complex. We investigated the microanatomy of the transtemporal-transchoroidal fissure approach to the ambient cistern with emphasis on exposure of the posterior cerebral artery. METHODS: Dissections were performed bilaterally in five silicone-injected cadaveric heads. Critical anatomic distances, specifically with reference to the P2 segment of posterior cerebral artery in relation to the inferior choroidal point and P2–P3 junction, were measured with digital calipers. Other landmarks (temporal lobe tip, points from the temporal base to the choroidal fissure) were included for quantitative analysis. RESULTS: The transtemporal-transchoroidal fissure approach provided adequate exposure of the ambient cistern, minimized temporal lobe retraction, and allowed assessment of regional microanatomy. The mean distance from the temporal base to the choroidal fissure measured 18.09 mm (range, 16.9–21.9 mm). The distances from the choroidal fissure to P2 varied at the coronal plane of the inferior choroidal point (mean, 6.96 mm; range, 3.6–12.0 mm) and the P2–P3 junction (mean, 6.02 mm; range, 4.3–6.9 mm), respectively. CONCLUSION: The transtemporal-transchoroidal fissure approach provides a corridor to the ambient cistern and P2–P3 junction while minimizing temporal lobe retraction and avoiding interruption of temporal lobe venous drainage. Because of widely variable vascular anatomy, access to posterior cerebral artery lesions using this approach requires preoperative imaging to identify the specific location of the P2–P3 junction.

Three-Dimensional Cortical Surface Reconstruction Versus Operative Findings: Their Similarity and Applications

BACKGROUNDnThree-dimensional cortical surface reconstruction (3DCSR) is an important tool for operations involving cerebral cortex, but data on its similarity to actual cortical architecture are lacking. In this study, the authors systematically tested the similarity between operative findings and 3DCSR built by a neuronavigation system and illustrated its applications.nnnMETHODSnThe authors retrospectively retrieved operative photographs and 3DCSR of patients who underwent craniotomy with the aid of 3DCSR and asked 4 evaluators to perform a series of matching tests. Test 1 was to match 3DCSR and operative photographs. Test 2 was a repetition of test 1 to determine the consistency of matching ability. Test 3 was to match detailed anatomy of the 3DCSR with operative photographs. Scores on all tests were analyzed to measure the degree of similarity between 3DCSR and operative findings. The scores between patients with and without cortical distortion were compared to determine the impact of distortion on matching ability.nnnRESULTSnTests of similarity were performed on 22 patients. Mean scores of tests 1, 2, and 3 were 84.09%, 93.18%, and 89.77%, respectively. The Kappa statistic for agreement between test 1 and 2 ranged from 0.76 to 0.88. There was no statistically significant difference between average score of patients with and without cortical distortion in all tests.nnnCONCLUSIONSnAuthors have systematically demonstrated that 3DCSR built by neuronavigation system in this study provides detailed anatomy of cortical surface with a high degree of similarity to operative findings even in the presence of cortical distortion, leading to various applications beyond navigation alone.

Localizing Value of Pain Distribution Patterns in Cervical Spondylosis

Study Design Prospective observational study. Purpose To investigate the value of pain distribution in localizing appropriate surgical levels in patients with cervical spondylosis. Overview of Literature Previous studies have investigated the value of pain drawings in its correlation with various features in degenerative spine diseases including surgical outcome, magnetic resonance imaging findings, discographic study, and psychogenic issues. However, there is no previous study on the value of pain drawings in identifying symptomatic levels for the surgery in cervical spondylosis. Methods The study collected data from patients with cervical spondylosis who underwent surgical treatment between August 2009 and July 2012. Pain diagrams drawn separately by each patient and physician were collected. Pain distribution patterns among various levels of surgery were analyzed by the chi-square test. Agreement between different pairs of data, including pain diagrams drawn by each patient and physician, intra-examiner agreement on interpretation of pain diagrams, inter-examiner agreement on interpretation of pain diagrams, interpretation of pain diagram by examiners and actual surgery, was analyzed by Kappa statistics. Results The study group consisted of 19 men and 28 women with an average age of 55.2 years. Average duration of symptoms was 16.8 months. There was no difference in the pain distribution pattern at any level of surgery. The agreement between pain diagram drawn by each patient and physician was moderate. Intra-examiner agreement was moderate. There was slight agreement of inter-examiners, examiners versus actual surgery. Conclusions Pain distribution pattern by itself has limited value in identifying surgical levels in patients with cervical spondylosis.