Surgical Strategy in Modification of the Transpetrosal Approach to Avoid Postoperative Venous Complications: A Report of 74 Consecutive Cases.

BACKGROUND: The transpetrosal approach is a complex skull base procedure with a high risk of complications, particularly caused by injury of the venous system. It is in part related to variability of blood outflow pathways and their distinctive patterns in each individual patient. OBJECTIVE: To evaluate outcomes and complications after skull base surgery with use of the petrosal approach modifications, which selection was based on the detailed preoperative assessment of venous drainage patterns. METHODS: Overall, 74 patients, who underwent surgery via the transpetrosal approach at our institution between 2000 and 2017, were included in this study. In all cases, the venous drainage pattern was assessed preoperatively and categorized according to the predominant blood outflow pathway into four types as previously suggested by Hacker: (1) sphenoparietal sinus (SpPrt), (2) sphenobasal vein (SpB), (3) sphenopetrosal sinus (SpPS), and (4) cortical. The blood outflow through the bridging petrosal vein and the vein of Labbé was also taken into consideration. In patients with SpPrt- and a cortical-type venous drainage, the transpetrosal approach was used in a standard way. In patients with SpB-type venous drainage, limited extradural anterior petrosectomy was combined with intradural anterior petrosectomy after dural opening, superior petrosal sinus transection, tentorial cutting, Meckel's cave opening, and trigeminal nerve mobilization. In patients with SpPS-type venous drainage, after standard petrosectomy, dural opening, and tentorial cutting, SpPS ligation was done followed by 2-week interval before staged definitive tumor resection. RESULTS: Gross total, near-total, and subtotal resection of the lesion (meningioma, 48 cases; retrochiasmatic craniopharyngioma, 11 cases; brain stem cavernoma, 7 cases; other tumors, 8 cases) was achieved in 30 (40.5%), 24 (32.4%), and 20 (27.0%) patients, respectively. Postoperative complications that were possibly related to venous compromise were noted in 18 patients (24.3%), but neither one was major. Of these 18 patients, 9 were symptomatic, but all symptoms-aphasia (4 cases), seizures (2 cases), and confusion (3 cases)-fully resolved after conservative treatment. Overall, 13 patients, including 4 symptomatic, had signal changes on T2-weighted brain MRI, which were permanent only in 3 cases (all asymptomatic). CONCLUSION: Our suggested surgical strategy can be applied to any type of the venous drainage pattern. Preoperative evaluation and intraoperative preservation of the blood outflow pathways are crucial means for safe and effective application of the transpetrosal approach.

[Use of Neurosurgical Patty].

The neurosurgical patty is used in almost every neurosurgical procedure. It has a diverse range of functions, including tissue protection, tissue manipulation, fluid management, and hemostasis. The author prefers to use two different types of patties; one is hard, in consistency with a thickness of 0.8 mm, and the other is soft, with a thickness of 0.2 mm. The former is used in retracting the brain with a spatula, and the latter for manipulating very delicate parts. To avoid adhesion at the interface between the patty and the brain, a collagen sheet is inserted under the patty. Care should be taken to avoid any iatrogenic damage to the brain surface, especially if the patty is placed under a spatula for a prolonged period. In such a situation, collagen sheets may remain. In tumor surgery, the patty is very useful for dissecting the gliotic layer of the brain from a relatively hard tumor, such as a large meningioma with pial invasion. Blunt dissection of the tumor by rotating the patty on the tumor surface, along with the gliotic layer, under the microscope, enables quick and accurate dissection of the tumor. Since surgical instruments are used by surgeons with varying levels of experiences, it is difficult to verify their correct evidence-based use. Here, the author's experience with the best use of the neurosurgical patty is described.

Surgical management for large vestibular schwannomas: a systematic review, meta-analysis, and consensus statement on behalf of the EANS skull base section.

BACKGROUND AND OBJECTIVE: The optimal management of large vestibular schwannomas continues to be debated. We constituted a task force comprising the members of the EANS skull base committee along with international experts to derive recommendations for the management of this problem from a European perspective. MATERIAL AND METHODS: A systematic review of MEDLINE database, in compliance with the PRISMA guidelines, was performed. A subgroup analysis screening all surgical series published within the last 20 years (January 2000 to March 2020) was performed. Weighted summary rates for tumor resection, oncological control, and facial nerve preservation were determined using meta-analysis models. This data along with contemporary practice patterns were discussed within the task force to generate consensual recommendations regarding preoperative evaluations, optimal surgical strategy, and follow-up management. RESULTS: Tumor classification grades should be systematically used in the perioperative management of patients, with large vestibular schwannomas (VS) defined as > 30 mm in the largest extrameatal diameter. Grading scales for pre- and postoperative hearing (AAO-HNS or GR) and facial nerve function (HB) are to be used for reporting functional outcome. There is a lack of consensus to support the superiority of any surgical strategy with respect to extent of resection and use of adjuvant radiosurgery. Intraoperative neuromonitoring needs to be routinely used to preserve neural function. Recommendations for postoperative clinico-radiological evaluations have been elucidated based on the surgical strategy employed. CONCLUSION: The main goal of management of large vestibular schwannomas should focus on maintaining/improving quality of life (QoL), making every attempt at facial/cochlear nerve functional preservation while ensuring optimal oncological control, thereby allowing to meet patient expectations. Despite the fact that this analysis yielded only a few Class B evidences and mostly expert opinions, it will guide practitioners to manage these patients and form the basis for future clinical trials.

Safety and accuracy of spinal instrumentation surgery in a hybrid operating room with an intraoperative cone-beam computed tomography.

Although spinal instrumentation technique has undergone revolutionary progress over the past few decades, it may still carry significant surgery-related risks. The purpose of the present study was to assess the radiological accuracy of spinal screw instrumentation using a hybrid operating room (OR) and quantify the related radiation exposure. This retrospective study included 33 cases of complex spine fusion surgeries that were conducted using a hybrid OR with a flat panel detector (FPD) angiography system. Twelve cases (36.4%) were cervical, and 21 (63.6%) were thoracolumbar. The average number of spine fusion levels was 3 and 4.8, respectively, at the cervical and thoracolumbar spine levels. A FPD angiography system was used for intraoperative cone-beam computed tomography (CBCT) to obtain multi-slice spine images. All operations were conducted under optimized radiation shielding. Entrance surface doses (ESDs) and exposure times were recorded in all cases. A total of 313 screws were placed. Satisfactory screw insertion could be achieved in all cases with safe screw placement in 97.4% and acceptable placement in 2.6%. None of the cases showed any significant anatomical violation by the screws. The radiation exposure to the patients was absolutely consistent with the desired ESD value, and that to the surgeons, under the annual dose limit. These results suggest that the hybrid OR with a FPD angiography system is helpful to achieve safe and precise spinal fusion surgery, especially in complex cases.

[Multiple Brain Embolism Due to Brachiocephalic Artery:A Case Report].

Embolisms arising from the brachiocephalic artery are very rare, of which there are few reports. We treated a patient with cerebral embolism originating from the brachiocephalic artery. The patient was a 71-year-old man with high blood pressure, diabetes, and hyperlipidemia, who presented with a sudden disturbance of consciousness and left hemiparesis, and cerebral infarction of the right frontal lobe, right parietal lobe, bilateral occipital lobe, and bilateral hemisphere of cerebellum. There was no significant stenosis of a major artery or atrial fibrillation. A floater in the blood vessel from the calcified part of the origin of the brachiocephalic artery was confirmed and assessed to be an occurrence due to cerebral embolism of the right internal carotid artery and basilar artery domains. Anticoagulant medical treatment was continued and the floating thrombus disappeared three months after onset. It was thought that it originated from the brachiocephalic artery, due to an embolism with clot adhesion. When treating a patient with a cerebral embolism that does not accord with the vascular territory, it was thought that elucidating the etiology using various modalities is important.

Surgical management of solitary nerve sheath tumors originating around the epiconus or conus medullaris: a retrospective case analysis based on neurological function.

The objective of this retrospective case analysis was to evaluate the surgical impact on neurological functional recovery in cases of solitary spinal nerve sheath tumors (NSTs) originating around the epiconus, conus medullaris, or cauda equina and not associated with neurofibromatosis. This 10-year surgical study included 30 cases of spinal NSTs originating around the spine level of T12-L1 (epiconus-to-conus medullaris: Epi-CM group), and 15 cases of spinal NSTs originating below the spine level of L2 (cauda equina: CE group). A minimally invasive posterior unilateral approach was applied in 22 of 30 subjects in the Epi-CM group and in 14 of 15 subjects in the CE group. Total removal of the tumor was achieved in all cases except in two cases of subpial growth and foraminal extension in the Epi-CM group at the initial surgery. Functional assessment revealed satisfactory or acceptable neurological recovery in both groups. Twelve of 30 patients (40%) in the Epi-CM group demonstrated significant motor weakness of the ipsilateral leg, predominantly manifested as drop foot before surgery, and only 4 of 12 patients demonstrated complete recovery. Ten of 30 patients (33%) in the Epi-CM group demonstrated a significant disturbance of urination before surgery, and only 6 of 10 demonstrated complete recovery. No patients in the CE group demonstrated unsatisfactory recovery of leg motor weakness or urinary disturbance. The present study suggests that surgeons should be aware that spinal NSTs originating around the epiconus or conus medullaris may result in delayed or inadequate functional recovery, even after successful surgical resection of tumors.

Safe maximal resection of primary cavernous sinus meningiomas via a minimal anterior and posterior combined transpetrosal approach.

OBJECTIVE Meningiomas arising from the cavernous sinus (CS) continue to be a significant technical challenge, and resection continues to carry a relatively higher risk of neurological morbidity in patients with these lesions because of the tumor's proximity to neurovascular structures. The authors report the surgical outcomes of 9 patients with primary CS meningiomas (CSMs) that were surgically treated using a minimal anterior and posterior combined (MAPC) transpetrosal approach, and they emphasize the usefulness of the approach. METHODS This retrospective study included 9 patients who underwent surgery for CSM treatment between 2015 and 2016 via the MAPC transpetrosal approach. Two patients were men and 7 were women, with a mean age of 58.5 years (39-72 years). Five patients (55.5%) had undergone previous treatment. The surgical technique consisted of a temporo-occipito-suboccipital craniotomy and exposure of the posterolateral part of the CS via the presigmoidal MAPC approach. After opening Meckel's cave and identifying the 3rd-5th cranial nerves in the prepontine cistern, Parkinson's triangle and supratrochlear triangles were opened. Finally, the tumor occupying the posterolateral part of the CS was removed. RESULTS All lesions were safely and maximally removed, with preservation of external ocular movements and preoperative Karnofsky Performance Scale scores. The mean extent of resection was 77.0% (range 58.7%-95.4%). Six patients underwent adjuvant therapy in the form of stereotactic radiosurgery (SRS) or stereotactic radiotherapy (SRT) during the follow-up period; none of these patients experienced recurrence. CONCLUSION The authors conclude that the MAPC transpetrosal approach could be superior to other approaches for CSMs, as it provides direct visual access to the posterolateral portion of the CS. In their experience, this approach is an alternative and better option for safe maximal resection of CSMs.

Schwannoma-like tumor in the anterior cranial fossa immunonegative for Leu7 but immunopositive for Schwann/2E.

Schwannoma arising from the olfactory system, often called olfactory groove schwannoma (OGS), is rare, as the olfactory bulb and tract, belonging to the central nervous system, should lack Schwann cells. Another rare entity called olfactory ensheathing cell tumor (OECT) has been reported, which mimics clinical and radiological characteristics of OGS. Here, we report two rare cases of schwannoma-like tumor in the anterior cranial fossa that showed negative staining for Leu7, but positive staining for Schwann/2E, and discuss their origin. Two cases of mass lesions in the anterior cranial fossa in a 26-year-old man and a 24-year-old woman were successfully removed. Morphological examination of these tumors was compatible with a diagnosis of schwannoma. Immunohistochemically, both cases were negative for Leu7, yielding a diagnosis of OECT, but were positive for the schwannoma-specific marker, Schwann/2E. Immunohistochemical staining results in our two cases question the current assumption that OGS and OECT can be distinguished only by Leu7 staining pattern. In conclusion, the origins of OGS and OECT remain to be determined, and further studies in larger numbers of cases are needed to characterize these rare tumors in the anterior cranial fossa.

A minimum 2-year comparative study of autologous cancellous bone grafting versus beta-tricalcium phosphate in anterior cervical discectomy and fusion using a rectangular titanium stand-alone cage.

Although titanium stand-alone cages are commonly used in anterior cervical discectomy and fusion (ACDF), there are several concerns such as cage subsidence after surgery. The efficacy of ß-tricalcium phosphate (ß-TCP) granules as a packing material in 1- or 2-level ACDF using a rectangular titanium stand-alone cage is not fully understood. The purpose of this study is to investigate the validity of rectangular titanium stand-alone cages in 1- and 2-level ACDF with ß-TCP. This retrospective study included 55 consecutive patients who underwent ACDF with autologous iliac cancellous bone grafting and 45 consecutive patients with ß-TCP grafting. All patients completed at least 2-year postoperative follow-up. Univariate and multivariate analyses were performed to examine the associations between study variables and nonunion after surgery. Significant neurological recovery after surgery was obtained in both groups. Cage subsidence was noted in 14 of 72 cages (19.4 %) in the autograft group and 12 of 64 cages (18.8 %) in the ß-TCP group. A total of 66 cages (91.7 %) in the autograft group showed osseous or partial union, and 58 cages (90.6 %) in the ß-TCP group showed osseous or partial union by 2 years after surgery. There were no significant differences in cage subsidence and the bony fusion rate between the two groups. Multivariate analysis using a logistic regression model showed that fusion level at C6/7, 2-level fusion, and cage subsidence of grades 2-3 were significantly associated with nonunion at 2 years after surgery. Although an acceptable surgical outcome with negligible complication appears to justify the use of rectangular titanium stand-alone cages in 1- and 2-level ACDF with ß-TCP, cage subsidence after surgery needs to be avoided to achieve acceptable bony fusion at the fused segments. Fusion level at C6/7 or 2-level fusion may be another risk factor of nonunion.

Characteristic of optic canal invasion in 31 consecutive cases with tuberculum sellae meningioma.

Optic canal invasion by tuberculum sellae meningiomas (TSMs) has been reported, but the characteristics of invasion remain unclear. This study was performed to clarify the incidence and characteristics of optic canal invasion by TSM and to determine whether optic canal invasion could be predicted preoperatively by magnetic resonance imaging (MRI). Between February 2002 and August 2014, 31 patients with TSM underwent tumor resection in our institute. In all cases, the optic canal was explored to identify any tumor invasion. We classified the characteristics of optic canal invasion from intraoperative findings. Invasion was classified into four types: type 1: no invasion; type 2: secondary invasion; type 3: partial wall invasion (two subtypes); and type 4: invasion into the supero-medial-inferior walls of the optic canal. Thirty of 31 cases showed optic canal invasion. Of these 30 cases, 9 (30 %) showed bilateral optic canal invasion. The most common finding was type 1 (23 sides). Among cases with optic canal invasion (39 sides), type 4 was the most common pattern (17 sides), followed by type 3-infero-medial (13 sides), type 2 (5 sides), and type 3-supero-medial (4 sides). Blinded prediction of tumor invasion was accurate in 61 % of cases, but characteristics of tumor invasion were undeterminable from preoperative MRI. In conclusion, optic canal invasion was frequently seen in our consecutive series of TSM, characteristics of which were unpredictable preoperatively. Neurosurgeons should be aware of the high incidence and variety of optic canal invasion in planning strategies for TSM treatment.

Aggressive surgery based on an anatomical subclassification of craniopharyngiomas.

OBJECTIVE Craniopharyngiomas remain a particularly formidable challenge in the neurosurgical field. Because these lesions involve the hypothalamus and ophthalmological systems, their resection is associated with either higher rates of mortality and recurrence or a lower rate of radical resection. The authors report the outcomes of aggressive surgeries based on an anatomical subclassification of craniopharyngiomas. METHODS Clinical and ophthalmological examinations, imaging studies, endocrinological studies, neuropsychological function, and surgical complications in all patients who had undergone microsurgical resection for craniopharyngioma at Osaka City University hospital between January 2000 and December 2014 were retrospectively reviewed through the medical records. Radical resections were planned in all of the patients. To help choose the correct surgical approach, craniopharyngiomas were classified based on tumor origin. The 4 possible groups included the intrasellar type, prechiasmatic type, retrochiasmatic type, and intra-third ventricle type. A multistage surgery was planned in some cases. RESULTS Seventy-two cases of craniopharyngioma were resected. Thirty-two patients (44.4%) had undergone previous surgical procedures at other institutions. Thirty-five cases (48.6%) were classified as retrochiasmatic, 19 (26.4%) as prechiasmatic, 12 (16.7%) as intra-third ventricle, and 6 (8.3%) as intrasellar. In 26 cases (36.1%), multistage surgery was required to complete the radical resection. Overall, 41 cases involved an orbitozygomatic approach; 21, a transpetrosal approach; 21, an interhemispheric approach; and 14, a transsphenoidal approach. In 3 cases, other approaches were applied. Gross-total resection was achieved in 43 patients (59.7%), near-total resection in 28 (38.9%), and partial resection in only 1 patient (1.4%). The mean follow-up period after resection was 4.7 years. Tumor recurrence or regrowth occurred in 15 (20.8%) of the 72 patients, with 14 of the 15 cases successfully controlled after additional resections and stereotactic radiosurgery. However, 1 patient died of uncontrollable tumor progression, and 2 patients died of unrelated diseases during the follow-up. Overall, disease in 69 (95.8%) of 72 patients was well controlled at the last follow-up. CONCLUSIONS Aggressive tumor resection is the authors' treatment policy for craniopharyngioma. Using an anatomical subclassification of craniopharyngioma to choose the most appropriate surgical approach is helpful in achieving that goal of aggressive resection.

Glioblastoma in long-term survivors of acute lymphoblastic leukemia: Report of two cases.

Acute lymphoblastic leukemia (ALL) is the most common form of cancer in children. Second neoplasms as late effects of therapy for ALL have been recognized as a significant clinical issue given the increasing number of long-term survivors of ALL, because they can be the cause of death in such cases. In contrast, glioblastoma (GBM) is the most common primary brain tumor in adults. It is a malignant brain tumor that most often occurs in elderly patients, and GBM in young adults or adolescents appears to be rare. Here, we describe our experience of two cases of GBM in young long-term survivors of ALL, and emphasize the necessity of careful follow up of patients treated for ALL for the potential occurrence of central nervous system second neoplasms, especially when the patients have previously undergone cranial radiotherapy.

Ability of NT-pro-BNP to Diagnose Cardioembolic Etiology in Patients with Acute Ischemic Stroke.

Background Cardioembolic stroke (CE) is usually associated with a larger ischemic area leading to higher morbidity and mortality rates. No biomarkers for CE are available, which causes difficulty in differential diagnosis of CE from other subtypes of acute ischemic stroke. Methods: We prospectively evaluated consecutive patients with acute ischemic stroke to identify biomarkers that could distinguish between CE and other subtypes of acute ischemic stroke. Etiological diagnoses were identified according to the National Institute of Neurological Disorders and Stroke (NINDS) 111 classification using clinical examinations, computed tomography (CT), magnetic resonance imaging (MRI), cardiac evaluations, and other tests. The biomarkers N-terminal pro-brain natriuretic peptide (NT-pro-BNP), Thrombin-Antithrombin III Complex (TAT), and D-dimer were determined in blood samples collected within 48 hours of onset and compared between groups with and without CE. Non- CE consisted of atherothrombotic brain infarction (ATBI), lacunar infarction (LI), and other stroke subtypes of unknown cause (other). Results: This study included 279 patients diagnosed with acute ischemic stroke. Serum levels of NT-pro- BNP were significantly higher in those with than in those without CE stroke (p<0.0001). Analysis of receiver operating characteristics (ROC) curves indicated that an NT-pro-BNP cutoff of 332 pg/mL provided optimal sensitivity (98.3%) and specificity (75.8%) for distinguishing CE from non-CE. Conclusions: Serum levels of NT-pro-BNP may help in diagnosis of CE during the acute phase and thus allow appropriate therapy t6 prevent subsequent cardiogenic stroke.

An innovative technique for detecting the caudal end of occluded inferior petrosal sinus in cavernous arteriovenous fistula using intravascular ultrasonography--technical note.

INTRODUCTION: Although cavernous sinus (CS) dural arteriovenous fistulas (d-AVFs) are usually treated with transvenous embolization (TVE) via the inferior petrosal sinus (IPS), IPSs are sometimes thrombosed and angiographically invisible. In such cases, the first obstacle to TVE is detecting the entry to the IPS. We report a new technique for TVE via IPS using intravascular ultrasonography (IVUS). METHODS: Three consecutive cases of CS d-AVF with ipsilateral or bilateral IPS occlusion were involved in this study. On TVE, the orifice of the IPS was investigated with IVUS placed in the jugular vein or jugular bulb. RESULTS: This technique has been successfully adapted in all three cases. In two of these cases, IPS was well visualized with the help of IVUS, and TVE was successfully performed. CONCLUSION: To our knowledge, this is the first report to mention the usefulness of IVUS for detecting angiographically occult IPS.

Staged 'intentional' bridging vein ligation: a safe strategy in gaining wide access to skull base tumors.

BACKGROUND: The venous drainage of the temporal lobe, through bridging veins to the middle cranial fossa, is pivotal in determining the surgical corridor for skull base lesions. In dealing with select cases, where venous drainage was an obstacle in the surgical approach, we hypothesized that staged 'intentional' ligation of the dominant pathway of venous drainage would provide a safer and wider access to skull base tumors. We study the indications and safety of this surgical strategy in the management of skull base lesions. MATERIALS AND METHODS: From 1995 to 2012, 318 patients with skull base tumors were treated at our institute by the fronto-orbito-zygomatic (FOZ) or transpetrosal approaches, eight of whom we planned for staged 'intentional' bridging vein ligation. Seven patients underwent planned ligation of the bridging veins from the temporal lobe to the middle cranial fossa floor in the first stage, followed by definitive surgery through the desired skull base approach, in the second stage, while in one patient the strategy was abandoned. These patients were evaluated with respect to their clinical presentation, pre- and post-operative radiology including venogram, intra-operative findings and post-operative course. RESULTS: Seven patients, four males and three females, with ages ranging from 16 to 63 years, underwent staged 'intentional' bridging vein ligation. The diagnoses were recurrent craniopharyngioma in four, and petroclival meningioma, sphenopetroclival meningioma and spheno-orbital meningioma in one each. Six of these lesions were approached from the dominant (left) side, while one lesion was on the right side. Venograms done after the first-stage procedure showed obliteration of the dominant venous drainage with opening up of anastomotic venous channels in all patients. All patients tolerated the first-stage procedure well; only one patient showed asymptomatic mild temporal lobe edema on MRI, which resolved in 3 weeks. None of the patients had venous complications after definitive surgery. One patient with recurrent chordoma, who was planned for staged ligation, did not undergo ligation as, intra-operatively, the draining channel turned out to be a cortical vein, which could be mobilized without ligation. CONCLUSION: In an attempt to detether the temporal lobe, the disconnection of the bridging veins from the temporal lobe to the middle cranial fossa floor in the first stage may lead to re-direction of the venous outflow over time. This may allow skull base surgeons a better surgical corridor and ensure safety of venous structures during the definitive surgery.

Purely endoscopic subtemporal keyhole anterior transpetrosal approach to access the petrous apex region: surgical techniques and early results.

OBJECTIVE: The anterior transpetrosal approach using a microscope to provide wider access to the petrous apex region has been described for radical resection of lesions of the middle and posterior skull base. The microscopic anterior transpetrosal approach (mATPA) requires a wide craniotomy and meticulous epidural procedures to minimize temporal lobe retraction. Recently, the clinical application of transcranial endoscopic keyhole approaches for minimally invasive surgery has been steadily expanding. In this study, the details of the purely endoscopic subtemporal keyhole ATPA (eATPA) for petrous apex lesions are described and its initial results are reported. METHODS: Between May 2022 and May 2023, the authors performed eATPA in 10 patients with petrous apex lesions, of which 6 were meningiomas, 3 were trigeminal schwannomas, and 1 was epidermoid cyst. The surgical procedure of the purely eATPA is as follows. After a small temporal craniotomy, the endoscopic procedure is started. The anterior rim of the petrous bone and Meckel's cave are exposed via an intradural subtemporal approach. The lesion is removed with additional drilling of Kawase's triangle, cutting the superior petrosal sinus, opening Meckel's cave, and cutting the tentorium. The authors also compared the outcomes of mATPA versus eATPA for consecutive cases of petrous apex lesions. RESULTS: Gross-total resection was achieved in 8 of the 10 patients. The average operative time was 4 hours 13 minutes. There were 3 cases of transient abducens nerve palsy and 1 case of trochlear nerve palsy in the postoperative period. No new-onset motor deficits or CSF leakage was noted in any of these patients. Only 1 patient exhibited postoperative asymptomatic temporal lobe edema. The Karnofsky Performance Scale (KPS) scores remained unchanged or improved for all patients postoperatively. Compared with mATPA, eATPA achieved a similar extent of resection and comparable postoperative KPS scores with a significantly shorter mean operative time, much smaller temporal craniotomy, and thus less mean blood loss during surgery with lower rates of new-onset temporal lobe edema in the postoperative period. CONCLUSIONS: An eATPA allows a direct route to access Meckel's cave and posterior cranial fossa lesions similar to conventional mATPA, with shortening the operative time and reducing the risk of postoperative temporal lobe edema. This eATPA is considered one of the new surgical techniques that can be expected to develop in the future.

Application and Advantages of the Trans-Unco-Discal (TUD) Approach for Cervical Spondylotic Myelopathy and Radiculopathy: Classification and Modification of Surgical Technique Based on the Location of Spinal Cord and/or Nerve Root Compression.

Purpose: We assess the application and advantages of modifying the trans-unco-discal (TUD) approach which we underwent for cervical myelo-radiculopathy. We present the surgical techniques of the modified TUD approach. Materials and Methods: The material was 180 cases where anterior cervical decompression (ACD) was performed by the modified TUD approach. We classified the material into four groups based on the location of the nerve root and/or spinal cord compression: I, compression of the root at intervertebral foramen (IVF); II, compression of the posterior margin of the vertebral body; III, compression of the IVF and posterior margin of the vertebral body; IV, compression of the bilateral IVF and posterior margin of the vertebral body. We applied the modified TUD approach to these four types. We present the surgical procedures and techniques for the modified TUD approach. The Japanese orthopedic association (JOA) score and neuroradiological alignment were examined. Results: The improvement rate of the JOA score was 78.4% at 6 months post-surgery and 77.5% in the most recent examinations. By the modified TUD approach, compressive lesions of the spinal cord and/or nerve roots were removed, and good alignment was acquired and sustained. Conclusions: ACD by the modified TUD approach safely achieved appropriate decompression for the spinal cord and/or nerve roots, and the patients had a high improvement rate and good alignment. Complications were less common than with other surgical procedures. If the TUD approach and endoscopic approaches can be combined, their application to new area is anticipated.

Simple and safe exposure of the sigmoid sinus with presigmoid approaches.

Although entire exposure of the sigmoid sinus has been recognized as a complicated procedure in presigmoid approaches, we developed a new technique to expose the sigmoid sinus quite safely and simply without tough bone work. This study aims to demonstrate our technique in detail and present the effect of the procedure. Between January 2004 and December 2010, 77 patients underwent operations via presigmoid approaches in our institute. In all cases, the sigmoid sinus was completely exposed with our new surgical technique. The key step to expose the sigmoid sinus in our technique is dissection of the sinus from the overlying inner cortical bone in an antegrade direction from the junction of the transverse-sigmoid sinus to the jugular bulb using a bone dissector, avoiding meticulous bone drilling. We retrospectively examined a surgical video of all cases and determined the operative time required to entirely expose the sigmoid sinus from the transverse-sigmoid junction to the jugular bulb. In all 77 cases, the sigmoid sinuses were safely exposed with our new technique, and there was no episode of sinus injury. The operative time required to expose the sigmoid sinus ranged from 9.4 to 28.2 min (mean, 14.5 min). Standard drilling techniques took 32.3 min (range, 18.4-46.6 min) in last 20 cases before adoption of new technique. The new technique significantly shortened the surgical time to expose the sigmoid sinus (p < 0.01, Welch's t test). Our new technique is very useful for safely and simply exposing the sigmoid sinus, especially for standard neurosurgeons.