Burak Cabuk

Fluorescein sodium-guided surgery in glioblastoma multiforme: a prospective evaluation

We have evaluated the influence of fluorescein-guided resection on gross total resection (GTR) and survival in a series of patients with GBM. Group 1 consisted of 47 patients given fluorescein and group 2 comprised 33 patients, on whom fluorescein was not used. Median survival time was 43.9 weeks in the patients given fluorescein and was 41.8 weeks in the non-fluorescein group. There was no statistically significant difference in survival between the two groups. However, the extent of resection had a powerful influence on the median survival time. Survival was 34.3 weeks after partial resection and 46.5 after GTR. Our data shows that the use of fluorescein injection is a simple procedure, which allows a significant increase in the number of patients having GTR (83 vs. 55%). Our findings are similar to a recently published multicentre Phase III randomized trial in which 5-aminolevulinic acid was used to facilitate resection of malignant glioma.

The learning curve in endoscopic pituitary surgery and our experience

Experience is the important point in reduction of the complications and in the effectiveness of the surgical procedure in pituitary surgery. Endoscopic pituitary surgery differs from microscopic surgery, since it requires a steep learning curve for endoscopic skills. In this article, we evaluate our learning curve in two groups, as early and late experience. Purely endoscopic transsphenoidal operations were performed on 78 patients, which were retrospectively reviewed and grouped as early and late experience groups. We used the purely endoscopic endonasal approach to the sella that was performed via an anterior sphenoidotomy, without the use of a transsphenoidal retractor. All patients with adenomas were evaluated considering operation time, endocrinology, ophthalmology, total removal and, especially, modifications of standard technique. On the basis of the experience gained with the use of the endoscope in transphenoidal surgery over the years, modifications can be performed on the different phases of the endoscopic approach. Reviewing our cases in two groups of period due to our experience showed that the effectiveness of endoscopic surgery increases and operation time decreases. In our study, we identified a learning curve in endoscopic pituitary surgery.

Immunohistochemical analysis of TIMP-2 and collagen types I and IV in experimental spinal cord ischemia-reperfusion injury in rats

Abstract Background Thoracic and thoracoabdominal aortic intervention carries a significant risk of spinal cord ischemia. The pathophysiologic mechanisms that cause hypoxic/ischemic injury to the spinal cord have not been totally explained. In normal spinal cord, neurons and glial cells do not express type IV collagen. Type IV collagen produced by reactive astrocytes is reported to participate in glial scar formation. Tissue inhibitors of metalloproteinases (TIMPs) are endogenous inhibitors that regulate the activity of the matrix metalloproteinases (MMPs). TIMP-2 binds strongly with MMP-2, facilitating activation by membrane-type MMP. Imbalance between TIMPs and MMPs can lead to excessive degradation of matrix components. Type IV collagen involved in the blood–brain barrier disruption and glial scar formation, TIMP-2 influences MMP-2 that controls degradation of collagen I and IV. Objective To examine the immunohistochemical analysis of TIMP-2 and collagen types I–IV in experimental spinal cord ischemia–reperfusion in rats. Methods Thirty-two male Wistar rats weighing 250–300 g were divided into four groups: group S: sham group (n = 8); group 0P: 30-minute occlusion without perfusion (n = 8); group 3P: 30-minute occlusion and 3-hour perfusion (n = 8); and group 24P: 30-minute occlusion and 24-hour perfusion (n = 8). Infrarenal aorta was cross-clamped at two sites by using two aneurysm clips for 30 minutes. Reperfusion was provided after removal of the clips. Lumbar spinal cord segments were removed for immunohistochemical analysis. Results TIMP-2 and collagen staining in 3-hour perfused (3P) group were nearly the same with sham group (S). TIMP-2 and collagen staining increased in the 24-hour perfused group. Conclusion Alterations in collagen levels may relate to the biphasic breakdown of the blood–brain barrier and collagen staining in new cell types with relation to glial scar formation. Our results demonstrate that 3-hour perfusion after occlusion in hypoxic/ischemic spinal cord injury seems to be the critical reversible period.

Matrix metalloproteinase-9 and tissue inhibitor of matrix metalloproteinase-2: Prognostic biological markers in invasive prolactinomas

In this study, the predictive roles of matrix metalloproteinase (MMP)-9 and tissue inhibitor of matrix metalloproteinase (TIMP)-1 and 2 in invasive and noninvasive prolactinomas were examined. Prognostic biomarkers to distinguish between invasive and noninvasive pituitary adenomas are required for the effective treatment of pituitary adenoma patients. We analyzed 57 prolactinoma patients classified as having invasive and noninvasive adenomas for MMP-9, TIMP-1 and TIMP-2 expression using immunohistochemical methods. Significantly higher MMP-9 expression was detected in invasive prolactinomas (p=0.004). There was also a significant relationship between TIMP-2 expression and invasive behavior (p=0.004) and TIMP-2 expression and recurrence (p=0.005). Because MMP-9 expression is significantly increased in invasive prolactinomas, MMP-9 has potential as a marker for invasion. TIMP-2 may be a marker for both invasion and recurrence. These findings require further examination in large scale prospective studies.

Endoscopic transphenoidal approach for fibrous dysplasia of clivus, tuberculum sellae and sphenoid sinus; report of three cases.

AIM Fibrous dysplasia is a benign disease in which medullary bone is replaced by fibro-osseous tissue, and causes distortion and overgrowth of the involved bone and represents about 3% of all bone tumors. There is variability in the manifestation of Fibrous Dysplasia lesions with imaging techniques due to their proportional variations of fibrous to osseous tissue. Radiological differential diagnoses include meningioma, chordoma on MRI and Paget disease on CT imagings. MATERIAL AND METHODS We report three cases of monostotic fibrous dysplasia, affecting clivus, tuberculum sellae, and sphenoid sinus through the pterygopalatine fossa. We performed pure endoscopic transphenoidal approach for those three cases with the guide of neuronavigation. Extended approach was used via binostril for fibrous dysplasia of clivus and Tuberculum sellae. RESULTS Radiologic report revealed chordoma and meningioma for the two cases and fibrous dysplasia for the last case. Total resection of tuberculum sellae, subtotal resection of clivus and partial resection of sphenoid sinus lesions were performed. Pathology diagnosis were fibrous dysplasia in all three patients. CONCLUSION Histopathological sampling provided by surgical approach should be obtained to establish the final diagnosis. Endoscopic approaches are convenient for skull base lesions even for biopsy or curative resections providing panoramic view and avoid brain retraction.

Detection and Evaluation of Intracranial Aneurysms with 3D-CT Angiography and Compatibility of Simulation View with Surgical Observation.

AIM The aim of this study was to report our experience with a 64-channel computerized tomography (CT) scanner as the primary choice on the detection of intracranial aneurysms. Comparison of intracranial aneurysms with the simulated images obtained via three-dimensional computed tomography angiography (3D-CTA) in pterional approach was also aimed. MATERIAL AND METHODS Among 288 consecutive patients who had intracranial aneurysms detected on 64-slice CTA, a total of 337 aneurysms were detected. CTA simulation images and intraoperative images were compared with regards to size, shape, and orientation. RESULTS In one of the 22 CTA-negative cases, one aneurysm was detected in DSA and an additional aneurysm was detected in a patient operated with CTA. Aneurysm size, shape and direction were error free except a few cases. However, CTA was found to be insufficient to show particularly perforating arteries that were smaller than 2 mm in size. CONCLUSION As a fast and noninvasive technique, CTA can be used as an initial examination in subarachnoid hemorrhage. Keeping the fact that there can be insufficiency in showing particularly small aneurysms in mind, DSA should be performed on CTA-negative cases and required cases.

The utility of preoperative acth/cortisol ratio for the diagnosis and prognosis of cushing's disease

Purpose: Cushings syndrome (CS) is a rare disease having diagnostic difficulties. Many diagnostic tests have been defined but none of these are diagnostic alone. Determination of the cause is another problem which sometimes requires more sophisticated and invasive procedures. Therefore, we aimed to evaluate the utility of pretreatment plasma adrenocorticotropic hormone (ACTH)/cortisol ratios in patients with confirmed endogenous CS for the diagnosis and differential diagnosis of CS. Materials and Methods: This retrospective evaluation included 145 patients with the diagnosis of CS, 119 patients with Cushings disease (CD), and 26 patients with ACTH-independent CS (AICS), in a university hospital. Furthermore, 114 individuals in whom CS diagnosis was excluded with at least one negative screening test were enrolled to the study as control group. The clinical, laboratory, imaging, postsurgical pathologic records and also clinical follow-up data of all patients were evaluated. Results: The median basal ACTH/cortisol ratio of the patients with CD was significantly higher than AICS and controls. A cutoff ACTH/cortisol ratio >2.5 was found to be diagnostic for CD with 82% specificity and 63% sensitivity. Among CD group, patients with recurrent disease had higher preoperative ACTH levels and ACTH/cortisol ratio than patients with sustained remission. Furthermore, these patients had more invasive, atypical, and larger tumors. Conclusion: An ACTH/cortisol ratio >2.5 would be beneficial to diagnose CD together with other diagnostic tests. It is a simple test with no additional cost. Higher ratios might be related with larger, invasive, and atypical adenoma and also might be helpful to predict recurrence.

A Haptic Guided Robotic System for Endoscope Positioning and Holding.

AIM To determine the feasibility, advantages, and disadvantages of using a robot for holding and maneuvering the endoscope in transnasal transsphenoidal surgery. MATERIAL AND METHODS The system used in this study was a Stewart Platform based robotic system that was developed by Kocaeli University Department of Mechatronics Engineering for positioning and holding of endoscope. After the first use on an artificial head model, the system was used on six fresh postmortem bodies that were provided by the Morgue Specialization Department of the Forensic Medicine Institute (Istanbul, Turkey). RESULTS The setup required for robotic system was easy, the time for registration procedure and setup of the robot takes 15 minutes. The resistance was felt on haptic arm in case of contact or friction with adjacent tissues. The adaptation process was shorter with the mouse to manipulate the endoscope. The endoscopic transsphenoidal approach was achieved with the robotic system. The endoscope was guided to the sphenoid ostium with the help of the robotic arm. CONCLUSION This robotic system can be used in endoscopic transsphenoidal surgery as an endoscope positioner and holder. The robot is able to change the position easily with the help of an assistant and prevents tremor, and provides a better field of vision for work.

Visual Outcome of an Endoscopic Endonasal Transsphenoidal Approach in Pituitary Macroadenomas: Quantitative Assessment with Diffusion Tensor Imaging Early and Long-Term Results

BACKGROUND Postoperative visual recovery in patients with pituitary adenoma can be influenced by the duration of symptoms, age, and tumor volume. Diffusion tensor imaging (DTI) allows visualization of white matter structure along with quantitative information. The aims of our study were to predict the visual recovery process in the early and long-term periods and to define the parameters affecting the recovery course. METHODS A total of 200 patients with pituitary macroadenomas underwent endoscopic transsphenoidal surgery between January 2009 and July 2016. DTI and visual analysis including visual acuity and visual field analyses were performed for these patients at 5 periods, which included 3 years of follow-up. The effects of age, duration of symptoms, and tumor volume on visual recovery were evaluated. RESULTS Mean tumor volume was calculated as 8871 ± 2758 mm3 and mean symptom duration was 23.41 ± 3.72 weeks. Mean age of the patients was 43.8 ± 8.9 years in the full recovery group and 48.7 ± 15.1 years in the nonrecovery group. Visual field analysis results on a Humphrey visual chart showed a significant linear strong correlation with fractional anisotropy (FA) values and a reverse strong correlation with mean diffusivity (MD) values on DTI magnetic resonance. DTI FA and MD cutoff values for each group were respectively determined as 0.373 and 1386 (×10-6 mm2/second) for the preoperative period, 0.423 and 1383 (×10-6 mm2/second) for the initial period, 0.428 and 1265 (×10-6 mm2/second) for the early period, 0.432 and 1238 (×10-6 mm2/second) for the intermediate period, and 0.437 and 1198 (×10-6 mm2/second) for the late period. CONCLUSIONS DTI can assess and predict visual recovery after endoscopic transsphenoidal surgery of patients with pituitary macroadenomas causing chiasmal compression. FA values lower than or MD values greater than the cutoff values of the specific period reflect poor prognosis. Tumor volume was found to be the featured parameter that affects visual recovery. The postoperative first year is the most prominent interval evaluating the prognosis of visual recovery.

Endoscopic approach to cavernous sinus aneurysm.

Aneurysms protruding into sellae may mimic pituitary tumors by compressing adjacent cranial nerves. Carotid-Cavernous aneurysms are rarely associated with mortality, and surgical intervention is recommended especially for neuro-ophthalmologic progression. In this report we presented a 51-year-old woman who had severe headache and neuro-ophthalmologic signs with the initial diagnosis of pituitary apoplexy on MRI (Magnetic Resonanse Imaging). However preoperative CTA (Computed Tomography Angiography) revealed a carotid cavernous aneurysm protruding into sellae. The patient underwent endovascular intervention and endoscopic transphenoidal approach for the removal of the hematoma compressing the cranial nerves. The patients neuro-ophthalmologic symptoms were improved during the follow-up, which may be related due to rapid evacuation of the hematoma.