When a wide polygonal dural window is created, a short dural incision length is preferred by surgeons because suturing a wastefully long incision line during closure is troublesome. A locator to facilitate making the shortest dural incision when creating a polygonal dural window would be helpful. We geometrically analyzed the shortest incision design for a pentagonal dural window and produced a simple locator for intraoperatively implementing this design. The design for a pentagonal dural window with the shortest incision is the same as the design for a minimum Steiner tree (MST) problem with five vertices. The MST consists of three interconnected Steiner points (SPs) with three equal, radiating branches. We produced a template of the features of the MST for a polygon (MST template) as a locator. The MST template consists of several uniform Steiner units (SUs), each of which has an SP at the center and three wings that branch off of the SP, and each SU also has three slits through which the wings of another unit can pass. This mechanism allows us to freely adjust the distance between the SPs of separate SUs. In clinical practice, we can create the shortest incision design for a quadrilateral or pentagon by arranging MST templates combining two or three SUs. If we open a wide dural window, the total incision lengths created using our method are 1–5 cm shorter than conventional incisions. The MST template accurately and easily reveals the shortest incision design.
Definitive radiotherapy is an important alternative treatment for meningioma patients who are inoperable or refuse surgery. We evaluated the efficacy and toxicity of CyberKnife-based stereotactic radiosurgery (SRS) and hypofractionated stereotactic radiotherapy (hSRT) as first-line treatments for intracranial meningiomas that were diagnosed using magnetic resonance imaging (MRI) and/or computed tomography (CT). Between February 2005 and September 2015, 41 patients with intracranial meningiomas were treated with CyberKnife-based SRS or hSRT. Eleven of those tumors were located in the skull base. The median tumor volume was 10.4 ml (range, 1.4–56.9 ml). The median prescribed radiation dose was 17 Gy (range, 13–20 Gy to the 61–88% isodose line) for SRS (n = 9) and 25 Gy (range, 14–38 Gy to the 44–83% isodose line) for hSRT (n = 32). The hSRT doses were delivered in 2 to 10 daily fractions. The median follow-up period was 49 months (range, 7–138). The 5-year progression-free survival rate (PFS) for all 41 patients was 86%. The 3-year PFS was 69% for the 14 patients with tumor volumes of ≥13.5 ml (30 mm in diameter) and 100% for the 27 patients with tumor volumes of <13.5 ml (P = 0.031). Grade >2 toxicities were observed in 5 patients (all of them had tumor volumes of ≥13.5 ml). SRS and hSRT are safe and effective against relatively small (<13.5 ml) meningiomas.
To estimate the duration of postoperative headache after surgery for acoustic neuroma and the effects of age, sex, tumor size, extent of tumor resection, type of skin incision, surgical duration, hearing preservation, and postoperative facial nerve palsy. This retrospective review analyzed clinical data from 97 patients who had undergone surgery for unilateral acoustic neuroma via the retrosigmoid approach >1 year previously. We investigated whether patients had headache at hospital discharge and during attendance at outpatient clinics. We classified postoperative headache as grade 0 (no headache), 1 (tolerable headache without medication), or 2 (headache requiring medication). The period of headache was defined as the interval in days between surgery and achievement of grade 0. The period of medication for headache was defined as the interval in days between surgery and achievement of grade 0 or 1. Kaplan-Meier analysis revealed median durations of medication and headache of 81 and 641 days, respectively. Headache was cured significantly earlier in patients who underwent surgery using a C-type skin incision (P < 0.001). Headache persisted significantly longer among patients who underwent a shorter surgical procedure (P < 0.02). Multivariate analysis confirmed the type of skin incision as a factor independently associated with duration of postoperative headache. Postoperative headache was cured in the majority of patients within about 2 years after surgery. The C-type skin incision is likely beneficial for reducing the duration of postoperative headache, although headache persisted in a small number of patients.
Contrast-induced encephalopathy is a very rare complication associated with endovascular treatment of intracranial aneurysms. Patients with renal dysfunction may be prone to developing contrast medium neurotoxicity as a result of delayed elimination of the contrast medium in renal metabolism. This article focuses on our experience with contrast-induced encephalopathy in patients with end-stage renal disease requiring hemodialysis. The authors retrospectively reviewed five patients diagnosed with contrast-induced encephalopathy who underwent aneurysm coil embolization at their institution from January 2006 to December 2015. During the 10-year period, embolization was performed in 755 cases, among which contrast-induced encephalopathy occurred in five patients (0.66%). Three of the five patients were undergoing dialysis for chronic renal failure (one male and two female; mean age 66.7). Embolization for hemodialysis patients was performed in eight during the same period and the incidence of contrast-induced encephalopathy in hemodialysis patients is quite high in our series (3 of 8; 38%). Procedures were performed in one for recurrence of unruptured anterior-communicating artery aneurysm and in two for unruptured basilar-tip aneurysm. Mean approximately 220 ml of contrast media was used among three hemodialysis patients. All three patients showed an improvement or a control in symptoms soon after hemodialysis. Recovery of neurological symptoms was complete in two and almost normal in one within 1 week after intervention. Contrast-induced encephalopathy should be kept in mind as an expected complication of aneurysm embolization in hemodialysis patients. In hemodialysis patients with contrast-induced encephalopathy, performing hemodialysis is an effective treatment to improve symptoms early.
Percutaneous endoscopic lumbar foraminotomy (ELF) is a novel minimally invasive technique used to treat lumbar foraminal stenosis. However, the validity of foraminal decompression based on quantitative assessment using magnetic resonance imaging (MRI) has not yet been established. The objective of this study was to investigate the radiographic efficiency of ELF using MRI. Radiographic changes of neuroforamen were measured based on pre- and postoperative MRI findings. Images were blindly analyzed by two observers for foraminal stenosis grade and foraminal dimensions. The intraclass correlation coefficient (ICC) and k statistic were calculated to determine interobserver agreement. Thirty-five patients with 40 neuroforamen were evaluated. The mean visual analog scale (VAS) score improved from 8.4 to 2.1, and the mean Oswestry disability index (ODI) improved from 65.9 to 19.2. Overall, 91.4% of the patients achieved good or excellent outcomes. The mean grade of foraminal stenosis significantly improved from 2.63 to 0.68. There were significant increases in the mean foraminal area (FA) from 50.05 to 92.03 mm2, in mean foraminal height (FH) from 11.36 to 13.47 mm, in mean superior foraminal width (SFW) from 6.43 to 9.27 mm, and in mean middle foraminal width (MFW) from 1.47 to 78 mm (P < 0.001). Interobserver agreements for preoperative and postoperative measurements were good to excellent with the exception of SFW. In conclusion, foraminal dimensions and grades of foraminal stenosis significantly improved after ELF. These findings may enhance the clinical relevance of endoscopic lumbar foraminal decompression.
With advanced understanding of molecular background and correlation with therapeutic outcomes, the revised 4th edition of World Health Organization (WHO) classification of central nervous system (CNS) tumors incorporated molecular information into the definition of diffuse gliomas. Indeed, oligodendroglioma and astrocytoma are now defined by molecular signature, with diagnosis of glioblastoma being made by histology. In parallel, numerous clinical trials are underway all over the world, and important findings are being produced every year that have an impact on patient outcomes. Moreover, novel therapies/technologies are also being actively developed; however, there are still many CNS tumors for which no effective therapy has been established except radiotherapy. In this article, the authors review the recent results of major clinical trials and present their treatment recommendations for patients with adult, supratentorial diffuse gliomas of grades II and III stratified according to the new WHO classification.
Although current treatment advances prolong patient survival, treatment for glioblastoma (GBM) in the elderly has become an emerging issue. The definition of “elderly” differs across articles; GBM predominantly occurs at an age ≥65 years, and the prognosis worsens with increasing age. Regarding molecular markers, isocitrate dehydrogenase (IDH) mutations are less common in the elderly with GBM. Meanwhile, O6-methylguanine DNA methyltransferase (MGMT) promoter methylation has been identified in approximately half of patients with GBM. Surgery should be considered as the first-line treatment even for elderly patients, and maximum safe resection is recommended if feasible. Concurrently, radiotherapy is the standard adjuvant therapy. Hypofractionated radiotherapy (e.g., 40 Gy/15 Fr) is suitable for elderly patients. Studies also supported the concurrent use of temozolomide (TMZ) with radiotherapy. In cases wherein elderly patients cannot tolerate chemoradiation, TMZ monotherapy is an effective option when MGMT promoter methylation is verified. Conversely, tumors with MGMT unmethylated promoter may be treated with radiotherapy alone to reduce the possible toxicity of TMZ. Meanwhile, the efficacy of bevacizumab (BEV) in elderly patients remains unclear. Similarly, further studies on the efficacy of carmustine wafers are needed. Based on current knowledge, we propose a treatment diagram for GBM in the elderly.