Kim Hk

Intracranial dural arteriovenous fistulas: clinical characteristics and management based on location and hemodynamics.

Objective A dural arteriovenous fistula (DAVF) generally refers to a vascular malformation of the wall of a major venous sinus. These lesions have diverse symptoms according to the location and venous drainage, and require multidisciplinary treatment. We report on our experience and analyze the treatment outcome of intracranial DAVFs for a nine-year period. Methods Between January 2000 and December 2008, 95 patients with intracranial DAVFs were enrolled in this study. A retrospective review of clinical records and imaging studies of all patients was conducted. Endovascular embolization, surgical interruption, gamma knife stereotactic radiosurgery (GKS), or combinations of these treatments were performed based on clinical symptoms, lesion location, and venous drainage pattern. Results Borden type I, II, and III were 34, 48, and 13 patients, respectively. Aggressive presentation was reported in 6% of Borden type I, 31% of Borden type II, and 77% of Borden type III DAVFs, respectively, and DAVFs involving transverse, sigmoid, and superior sagittal sinus. Overall, the rate of complete obliteration was 68%. The complete occlusion rates with a combination treatment of endovascular embolization and surgery, surgery alone, and endovascular embolization were 89%, 86%, and 80%, respectively. When GKS was used with embolization, the obliteration rate was 83%, although it was only 54% in GKS alone. Spontaneous obliteration of the DAVF occurred in three patients. There were a few complications, including hemiparesis (in microsurgery), intracranial hemorrhage (in endovascular embolization), and facial palsy (in GKS). Conclusion The hemorrhagic risk of DAVFs is dependent on the location and hemodynamics of the lesions. Strategies for treatment of intracranial DAVFs should be decided according to the characteristic of the DAVFs, based on the location and drainage pattern. GKS can be used as an optional treatment for intracranial DAVFs.

Meningeal Layers Around Anterior Clinoid Process as a Delicate Area in Extradural Anterior Clinoidectomy : Anatomical and Clinical Study

Objective Removal of the anterior clinoid process (ACP) is an essential process in the surgery of giant or complex aneurysms located near the proximal internal carotid artery or the distal basilar artery. An extradural clinoidectomy must be performed within the limits of the meningeal layers surrounding the ACP to prevent morbid complications. To identify the safest method of extradural exposure of the ACP, anatomical studies were done on cadaver heads. Methods Anatomical dissections for extradural exposure of the ACP were performed on both sides of seven cadavers. Before dividing the frontotemporal dural fold (FTDF), we measured its length from the superomedial apex attached to the periorbita to the posterolateral apex which connects to the anterosuperior end of the cavernous sinus. Results The average length of the FTDF on cadaver dissections was 7 mm on the right side and 7.14 mm on the left side. Cranial nerves were usually exposed when cutting FTDF more than 7 mm of the FTDF. Conclusion The most delicate area in an extradural anterior clinoidectomy is the junction of the FTDF and the anterior triangular apex of the cavernous sinus. The FTDF must be cut from the anterior side of the triangle at the periorbital side rather than from the dural side. The length of the FTDF incision must not exceed 7 mm to avoid cranial nerve injury.

Endoscope-Assisted Microsurgical Removal of an Epidermoid Tumor within the Cavernous Sinus

Epidermoid tumor of the cavernous sinus is rare. The aim of this case report is to discuss the role of neuroendoscopes in the removal of such lesions. A 21-year-old man presented with 6-year history of progressive headache, diplopia, and visual disturbance. Work-up revealed an epidermoid tumor located in the right cavernous sinus. An extradural transcavernous approach was utilized via a traditional frontotemporal craniotomy with endoscopic assistance. The postoperative course was uneventful with immediate improvement of the patients headache. Postoperative magnetic resonance imaging demonstrated complete removal of the tumor. There were no signs of recurrence during a 2-year follow-up period. The endoscope is a useful tool for removing epidermoid tumors from the cavernous sinus and enhances visualization of areas that would otherwise be difficult to visualize with microscopes alone. Endoscopes also help minimize the retraction of neurovascular structures.

Surgical Results and Risk Factors for Recurrence of Lumbar Disc Herniation

Objective Recurrent lumbar disc herniation has been defined as disc herniation at the same level, regardless of ipsilateral or contralateral herniation, with a pain-free interval greater than 6 months. The aim of this study is to analyze outcomes and identify the potential risk factors for recurrent lumbar disc herniation. Methods The authors retrospectively reviewed the cases of 178 patients who underwent open discectomy for single-level lumbar disc herniation. Visual analogue scales and modified Macnab criteria were used to compare the clinical outcomes between the recurrent group and the non-recurrent group. Sex, age, discectomy level, degree of disc degeneration, type of disc herniation, pain-free interval after first-operation, smoking status, and trauma were investigated as potential recurrence risk factors. Results Of the 178 patients for whom the authors were able to definitely assess symptomatic recurrence status, 18 patients (10.1%) underwent revision surgery for recurrent disc herniation. The most common level involved was L4-L5 (61%) and the mean period of time to recurrence was 18.7 months (6-61 months). There were 17 cases of ipsilateral herniation and 1 case of contralateral herniation. The types of herniation for which revision surgery was done were protrusion (3 cases), and transligamentous extrusion (14 cases). There were five excellent, eight good, and two fair results. Conclusion Repeated discectomy for recurrent disc herniation produced unsatisfactory outcomes. Factors such as sex, type of disc herniation and traumatic events were found to be significant risk factors.

Cochlear line: a novel landmark for hearing preservation using the anterior petrosal approach

OBJECT The goal of this study was to develop a practical landmark for the safe and easy identification of the cochlea when performing anterior petrosectomy based on cadaver dissection results. METHODS The cochlear line was defined as the line drawn from the crossing point between the greater superficial petrosal nerve (GSPN) and the petrous internal carotid artery to the line drawn over the apex of the superior circumference of the dura of the internal auditory canal at a right angle. The validity of the cochlear line marking the anteromedial perimeter of the cochlea at the angle of the GSPN and the internal acoustic canal as a practical landmark were evaluated using 5 cadaver heads. RESULTS The mean distance (± SD) measured from the cochlear line to the margin of the cochlear cavity was 2.25 ± 0.51 mm (range 1.50-3.00 mm). CONCLUSIONS Anterior petrosectomy can be performed more efficiently by using the cochlear line as a key landmark to preserve the cochlea.

An Early Comparative Analysis of the Use of Autograft Versus Allograft in Anterior Cervical Discectomy and Fusion

Objective The purpose of this study is to verify the usefulness of autograft versus allograft in the radiographic and clinical outcome in early period after the surgery. Methods We performed a retrospective review of 38 patients who had undergone one- or two-level anterior cervical discectomy and fusion (ACDF) with rigid anterior plate fixation from March 2006 to May 2009. Interbody graft materials were iliac autograft (n=17) or with allograft (n=21). Fusion rate and graft collapse rate were assessed by radiographic analysis and clinical outcome was based on Odoms criteria. Results In autograft group, 13 patients achieved successful bone fusion (65%), whereas 7 patients (31.8%) in allograft group. There was statistically significant between two groups (p<0.05). Comparing immediate postoperative radiograph with last follow-up, the mean graft collapse was noted 1.3mm(15.5% change) in autograft group, whereas 2.0mm(24.7% change) in allograft group. There was no statistically significant collapse rate in autograft group (p>0.05), but statistically significant in allograft group (p<0.05). Clinical outcome was excellent or good in 94.1% in autograft group, and 90.5% in allograft group. Conclusion In study, anterior cervical interbody fusion with an allograft got a result of lower fusion rate and higher collapse rate compared with autograft in early period after surgery, and clinical outcome showed similar results in both groups.

Effectiveness of nicardipine for blood pressure control in patients with subarachnoid hemorrhage.

Objective The purpose of the study is to determine the effectiveness and safety of nicardipine infusion for controlling blood pressure in patients with subarachnoid hemorrhage (SAH). Methods We prospectively evaluated 52 patients with SAH and treated with nicardipine infusion for blood pressure control in a 29 months period. The mean blood pressure of pre-injection, bolus injection and continuous injection period were compared. This study evaluated the effectiveness of nicardipine for each Fisher grade, for different dose of continuous nicardipine infusion, and for the subgroups of systolic blood pressure. Results The blood pressure measurement showed that the mean systolic blood pressure / diastolic blood pressure (SBP/DBP) in continuous injection period (120.9/63.0 mmHg) was significantly lower than pre-injection period (145.6/80.3 mmHg) and bolus injection period (134.2/71.3 mmHg), and these were statistically significant (p < 0.001). In each subgroups of Fisher grade and different dose, SBP/DBP also decreased after the use of nicardipine. These were statistically significant (p < 0.05), but there was no significant difference in effectiveness between subgroups (p > 0.05). Furthermore, controlling blood pressure was more effective when injecting higher dose of nicardipine in higher SBP group rather than injecting lower dose in lower SBP group, and it also was statistically significant (p < 0.05). During the infusion, hypotension and cardiogenic problems were transiently combined in five cases. However, patients recovered without any complications. Conclusion Nicardipine is an effective and safe agent for controlling acutely elevated blood pressure after SAH. A more systemic study with larger patients population will provide significant results and will bring solid evidence on effectiveness of nicardipine in SAH.