Bilateral subdural hematoma caused by spontaneous intracranial hypotension originating from a discogenic microspur successfully treated with duraplasty: A case report.

Introduction: Discogenic microspurs are calcified outgrowths from the intervertebral disc which can perforate the dura, causing a leak of cerebrospinal fluid (CSF). Spontaneous leaks of the CSF present a recognized cause of spontaneous intracranial hypotension (SIH). Moreover, subdural hematomas (SDH) are a potentially severe complication of SIH. Research question: We present a case of a bilateral subdural hematoma without orthostatic headaches caused by a discogenic microspur protruding from the T1-2 intervertebral disc. The microspur is conjectured to be the culprit of the leak by ventrally perforating the dura and catalyzing the causal chain leading to the formation of the subdural hemorrhage. Material and methods: A 79-year woman noticed a progressive gait disturbance accompanied by a decline of short-term memory over several months without experiencing orthostatic headaches. Magnetic resonance imaging (MRI) showed extensive bilateral subdural fronto-parietal hematoma, signs of CSF hypotension (dilated venous compartments), and computed tomography (CT) myelography revealed a CSF leak originating at the T1-2 level. Results: The leakage site was treated with microsurgical duraplasty leading to a regression of the symptoms and complete resolution of the subdural hematomas within five postoperative months. Discussion and conclusion: Discogenic microspurs can perforate the dura causing a CSF leak, leading to spontaneous intracranial hypotension, finally resulting in a bilateral subdural hematoma. This constellation of symptoms does not necessarily induce orthostatic headaches and can be treated with microsurgical duraplasty.

Three-dimensional structure of the basal lamella of the middle turbinate.

The middle turbinate's basal lamella (3BL) is a variable landmark which needs to be understood in endoscopic transnasal skull base surgery. It comprises an anterior frontal and a posterior horizontal part and appears in its simplest depiction to be "L"-shaped, when viewed laterally. In this study we analyzed its 3D morphology and variations focusing on a precise and systematic description of the anatomy. CBCTs of 25 adults, 19 cadavers and 6 skulls (total: 100 sides) were investigated with the 3DSlicer software, creating 3D models of the 3BL. We introduced a novel geometrical classification of the 3BL's shape, based on segments. We analyzed their parameters and relationship to neighboring structures. When viewed laterally, there was no consistent "L"-shaped appearance of the 3BL, as it is frequently quoted. A classification of 9 segment types was used to describe the 3BL. The 3BLs had in average of 2.95 ± 0.70 segments (median: 3), the most frequent was the horizontal plate (23.05% of all segments), next a concave/convex plate (22.71%), then a sigma plate (22.37%). Further types were rare. We identified a horizontal plate in 68% of all lateral views whilst 32% of the 3BLs were vertical. A sigma-concave/convex-horizontal trisegmental 3BL was the most common phenotype (27%). Globally, the sigma-concave/convex pattern was present in 42%. The 3BL adhered the ethmoidal bulla in 87%. The segmenting method is eligible to describe the 3BL's sophisticated morphology.

The endoscope-assisted supraorbital "keyhole" approach for anterior skull base meningiomas: an updated meta-analysis.

INTRODUCTION: The gold-standard treatment for symptomatic anterior skull base meningiomas is surgical resection. The endoscope-assisted supraorbital "keyhole" approach (eSKA) is a promising technique for surgical resection of olfactory groove (OGM) and tuberculum sellae meningioma (TSM) but has yet to be compared with the microscopic transcranial (mTCA) and the expanded endoscopic endonasal approach (EEA) in the context of existing literature. METHODS: An updated study-level meta-analysis on surgical outcomes and complications of OGM and TSM operated with the eSKA, mTCA, and EEA was conducted using random-effect models. RESULTS: A total of 2285 articles were screened, yielding 96 studies (2191 TSM and 1510 OGM patients). In terms of effectiveness, gross total resection incidence was highest in mTCA (89.6% TSM, 91.1% OGM), followed by eSKA (85.2% TSM, 84.9% OGM) and EEA (83.9% TSM, 82.8% OGM). Additionally, the EEA group had the highest incidence of visual improvement (81.9% TSM, 54.6% OGM), followed by eSKA (65.9% TSM, 52.9% OGM) and mTCA (63.9% TSM, 45.7% OGM). However, in terms of safety, the EEA possessed the highest cerebrospinal fluid leak incidence (9.2% TSM, 14.5% OGM), compared with eSKA (2.1% TSM, 1.6% OGM) and mTCA (1.6% TSM, 6.5% OGM). Finally, mortality and intraoperative arterial injury were 1% or lower across all subgroups. CONCLUSIONS: In the context of diverse study populations, the eSKA appeared not to be associated with increased adverse outcomes when compared with mTCA and EEA and offered comparable effectiveness. Case-selection is paramount in establishing a role for the eSKA in anterior skull base tumours.

Endoscopic unilateral transethmoid-paraseptal approach to the central skull base.

Objectives: The endoscopic technique in transnasal skull base surgery offers optimal visualization and free manipulation in the surgical field. However, it may cause approach-related sinonasal injury, influencing patients' quality of life (QOL). To minimize rhinological morbidity without restrictions in surgical manipulation and tumor resection, we introduced the unilateral transethmoidal-paraseptal approach. In this article, we analyzed the long-term results and sinonasal outcome of this technique. Study Design: Retrospective analysis of medical records. Methods: Forty-two consecutive patients underwent surgery between June 2010 and March 2014 using the transethmoid-paraseptal approach. Perioperative work-up included neurological, radiological, endocrinological, ophthalmological, and rhinological analysis. Patients' preoperative, 1-month and 1-year postoperative QOL was measured using the Sino-Nasal Outcome Test (SNOT-22). Results: At all individuals, a unilateral transethmoid-paraseptal approach was performed. Removal of the turbinates, posterior septal resection or a conversion to biportal surgery could be avoided in all cases. There were no intraoperative neurovascular complications. All patients had a notable improvement in any disease-related symptoms, as well as by objective criteria. Complete tumor resection was aimed in 39 cases and achieved in 31 of them. The SNOT-22 scores transiently worsened 1 month after surgery and non-significantly improved after 1 year, compared with the preoperative status. A subgroup of 7 patients with preoperative sinonasal disease evidence showed continuous significant improvement (p < .05) of SNOT-22 scores across time. The smell screening tests showed no significant difference across time. Conclusion: The described approach allows safe removal of various skull base lesions without deterioration in sinonasal QOL and smell function. Level of Evidence: 4.

How I do it: The expanded trans/supraorbital approach for large space-occupying lesions of the anterior fossa.

BACKGROUND: The supraorbital rim often interferes with the required upward movement of the instruments for resection of large frontal-lobe tumours through a classic supraorbital craniotomy. Here, we present the expanded trans/supraorbital approach to overcome these limitations. METHODS: After an eyebrow skin incision, a one-piece bone flap was created incorporating the orbital rim and roof. Basal extension of the craniotomy allowed for a better intracranial visualisation with improved manoeuvrability and angulation of the instruments without using brain retraction. CONCLUSIONS: This approach poses a feasible alternative to large frontal craniotomies for frontal-lobe tumours, for which a regular supraorbital craniotomy is insufficient.

How I do it: the mononostril endonasal transethmoidal-paraseptal approach.

BACKGROUND: The use of endoscopes in transnasal surgery offers increased visualization. To minimize rhinological morbidity without restriction in manipulation, we introduced the mononostril transethmoidal-paraseptal approach. METHODS: The aim of the transethmoidal-paraseptal approach is to create sufficient space within the nasal cavity, without removal of nasal turbinates and septum. Therefore, as a first step, a partial ethmoidectomy is performed. The middle and superior turbinates are then lateralized into the ethmoidal space, allowing a wide sphenoidotomy with exposure of the central skull base. CONCLUSIONS: This minimally invasive transethmoidal-paraseptal approach is a feasible alternative to traumatic transnasal concepts with middle turbinate and extended septal resection.

Aneurysm Surgery with Preoperative Three-Dimensional Planning in a Virtual Reality Environment: Technique and Outcome Analysis.

OBJECTIVE: Aneurysm surgery demands precise spatial understanding of the vascular anatomy and its surroundings. We report on a decade of experience planning clipping procedures preoperatively in a virtual reality (VR) workstation and present outcomes with respect to mortality, morbidity, and aneurysm occlusion rate. METHODS: Between 2006 and 2015, the clipping of 115 intracranial aneurysms in 105 patients was preoperatively planned with the Dextroscope, a stereoscopic, patient-specific VR environment. The outcome data for all cases, planned and performed in 3 institutions, were analyzed based on clinical charts and radiologic reports. RESULTS: Eighty-five incidental, unruptured aneurysms in 77 patients were electively planned and treated surgically. Mortality was 0% and morbidity (modified Rankin Scale score >2) was 2.6%. The rate of complete aneurysm obliteration on postoperative imaging was 91.8%. In addition, 30 aneurysms were treated in 28 patients with previous subarachnoid hemorrhage. Mortality in these cases was 3.6%, morbidity (modified Rankin Scale score >2) 7.1%, and the rate of complete aneurysm clipping was 90%. CONCLUSIONS: Meticulous three-dimensional surgical planning in a VR environment enhances the surgeon's spatial understanding of the individual vascular anatomy and allows clip preselection and positioning as well as anticipation of potential difficulties and complications. VR planning was associated, in this multi-institutional series, with excellent clinical outcomes and rates of complete aneurysm closure equivalent to benchmark cohorts.

Endoscopic fenestration of intraventricular cerebrospinal fluid cysts: the contralateral approach.

OBJECTIVE: The endoscopic fenestration of intraventricular CSF cysts has evolved into a well-accepted treatment modality. However, definition of the optimal trajectory for endoscopic fenestration may be difficult. Distorted ventricular anatomy and poor visibility within the cyst due to its contents can make endoscopic fenestration challenging if approached from the ipsilateral side. In addition, transcortical approaches can theoretically cause injury to eloquent cortex, particularly in patients with dominant-sided lesions. The aim of this study was to examine the value of the contralateral transcortical transventricular approach in patients with dominant-sided ventricular cysts. METHODS: During a 5-year period between 2007 and 2011, 31 patients with intraventricular CSF cysts underwent surgery by the senior author (R.R.). Fourteen of these patients had cysts located on the dominant side. An image-guided endoscopic cyst fenestration via the contralateral transcortical transventricular approach was performed in 11 patients. A retrospective chart review was performed in all these patients to extract data on clinical presentation, operative technique, and surgical outcome. RESULTS: The most common presenting symptom was headache, followed by memory deficits and cognitive deterioration. In all cases CSF cysts were space occupying, with associated obstructive hydrocephalus in 8 patients. Image-guided endoscopic fenestration was successfully performed in all cases, with septum pellucidotomy necessary in 6 cases, and endoscopic third ventriculostomy in 1 case for additional aqueductal occlusion. Postoperative clinical outcome was excellent, with no associated permanent neurological or neuropsychological morbidity. No recurrent cysts were observed over a mean follow-up period of 2 years and 3 months. CONCLUSIONS: The contralateral approach to ventricular cysts can achieve excellent surgical outcomes while minimizing approach-related trauma to the dominant hemisphere. Careful case selection is essential to ensure that the contralateral endoscopic trajectory is the best possible exposure for sufficient cyst fenestration and restoration of CSF circulation.

Minimally invasive keyhole approaches in spinal intradural tumor surgery: report of two cases and conceptual considerations.

Despite their predominantly histologically benign nature, intradural tumors may become symptomatic by virtue of their space-occupying effect, causing severe neurological deficits. The gold standard treatment is total excision of the lesion; however, extended dorsal and dorsolateral approaches may cause late complications due to iatrogenic destruction of the posterolateral elements of the spine. In this article, we describe our concept of minimally invasive spinal tumor surgery. Two illustrative cases demonstrate the feasibility and safety of keyhole fenestrations exposing the spinal canal.

Stereoscopic neuroanatomy lectures using a three-dimensional virtual reality environment.

INTRODUCTION: Three-dimensional (3D) computer graphics are increasingly used to supplement the teaching of anatomy. While most systems consist of a program which produces 3D renderings on a workstation with a standard screen, the Dextrobeam virtual reality VR environment allows the presentation of spatial neuroanatomical models to larger groups of students through a stereoscopic projection system. MATERIALS AND METHODS: Second-year medical students (n=169) were randomly allocated to receive a standardised pre-recorded audio lecture detailing the anatomy of the third ventricle accompanied by either a two-dimensional (2D) PowerPoint presentation (n=80) or a 3D animated tour of the third ventricle with the DextroBeam. Students completed a 10-question multiple-choice exam based on the content learned and a subjective evaluation of the teaching method immediately after the lecture. RESULTS: Students in the 2D group achieved a mean score of 5.19 (±2.12) compared to 5.45 (±2.16) in the 3D group, with the results in the 3D group statistically non-inferior to those of the 2D group (p<0.0001). The students rated the 3D method superior to 2D teaching in four domains (spatial understanding, application in future anatomy classes, effectiveness, enjoyableness) (p<0.01). CONCLUSION: Stereoscopically enhanced 3D lectures are valid methods of imparting neuroanatomical knowledge and are well received by students. More research is required to define and develop the role of large-group VR systems in modern neuroanatomy curricula.

The supraorbital keyhole approach: how I do it.

BACKGROUND: Improvements in image guidance, endoscopy, and instruments, have significantly advanced "keyhole" neurosurgery. We describe the concept and technique of the supraorbital keyhole approach. METHODS: The supraorbital keyhole approach is performed through an eyebrow skin incision. Image guidance may be used to define the optimal surgical trajectory. A limited supraorbital craniotomy is fashioned. The frontal lobe is mobilized and the central skull base approached, without the need for brain retractors. Endoscopy is used to enhance visualization, and tube-shaft instruments to improve manipulation through the narrow surgical corridor. CONCLUSIONS: The supraorbital keyhole approach provides a safe method to access selected skull base lesions.

The supraorbital endoscopic approach for aneurysms.

OBJECTIVE: To review our surgical experience in minimally invasive transcranial endoscope-assisted microsurgical treatment of intracranial aneurysms, using the supraorbital keyhole craniotomy. METHODS: The supraorbital keyhole approach was performed through an eyebrow skin incision in 793 cases for treatment of 989 intracranial aneurysms. Of patients, 474 were operated on after subarachnoid hemorrhage, and 319 were operated on under elective conditions. After lateral frontobasal burr hole trephination, a limited subfrontal craniotomy was created. To achieve adequate intraoperative exposure through the limited approach, endoscopes were used routinely. Surgical outcome was assessed using the modified Rankin scale. RESULTS: The transcranial endoscope-assisted microneurosurgery technique was used routinely via a supraorbital approach. In 152 operations (19.1%), the endoscope provided important visual information in the vicinity of the aneurysm, revealing subsequent clip repositioning. The results of incidental aneurysms were excellent with a modified Rankin scale score ≤2 in 96.52%. The overall outcome of ruptured aneurysms was good with a modified Rankin scale score ≤2 in 72.2% of patients. There were no approach-related intraoperative or postoperative complications. CONCLUSIONS: The minimally invasive supraorbital keyhole approach allowed safe surgical treatment of intracranial aneurysms, including after subarachnoid hemorrhage. The markedly improved endoscopic visualization increased the assessment of clip placement with ideal control of surrounding vessels including perforators for identification of incorrect clip position.

Combined transnasal and transcranial removal of a giant clival chordoma.

Clival chordomas confront the surgeon with the task of resecting an aggressively invasive and destructive tumor in a critical surrounding. For many, mainly smaller, chordomas, the transnasal transclival approach is a feasible and safe surgical access. Larger tumors and especially those with extensive intradural, retrochiasmal, and/or deep cervical expansion are mostly approached by open craniotomy. Staged procedures are also commonly used in the case of expansive tumor growth. We present the first case of a single-session combined transnasal and transcranial approach to radically resect a large clival chordoma.

Patients' cosmetic satisfaction, pain, and functional outcomes after supraorbital craniotomy through an eyebrow incision.

OBJECT: The supraorbital approach through an eyebrow incision offers the opportunity to access a wide variety of lesions of the anterior, middle, and even the posterior fossa. The minimally invasive keyhole craniotomy limits brain exploration and retraction and offers the potential for improved surgical outcomes and reduced approach-related complications. Patient satisfaction, however, has not yet been reported in the literature. METHODS: From January 2002 through December 2011, the lead author (R.R.) used a supraorbital approach through an eyebrow incision for 418 patients with cerebral aneurysms, brain tumors or cystic lesions, and other miscellaneous pathological conditions. For 408 of these patients, a detailed retrospective case note review was conducted to extract data on surgical outcomes and complications, and 375 patients completed a follow-up patient satisfaction questionnaire. RESULTS: During the early perioperative period, 8 patients died (overall mortality rate 2.0%). Among patients surveyed, the overall level of satisfaction was high. Patients rated pain from the scar and headache on a scale from 1 to 5 (1 = no pain, 5 = severe pain) as follows: pain was a score of 1 for 289 patients (77.0%), 2 for 46 (12.3%), 3 for 22 (5.9%), 4 for 12 (3.2%), and 5 for 6 (1.6%). Patients also rated cosmetic outcome on a scale from 1 to 5 (1 = very pleasant, 5 = very unpleasant) as follows: outcome was a score of 1 for 315 patients (84.0%), 2 for 33 (8.8%), 3 for 14 (3.7%), 4 for 10 (2.7%), and 5 for 3 (0.8%). Postoperative chewing difficulty was reported for 8 patients (8 [2.1%] temporary, 0 permanent); palsy of the frontal muscle for 21 patients (5.6%; 13 [3.5%] temporary, 8 [2.1%] permanent); frontal hypesthesia for 31 patients (8.3%; 18 [4.8%] temporary, 13 [3.4%] permanent); and hyposmia for 11 patients (2.9%; 3 [0.8%] temporary, 8 [2.1%] permanent). CONCLUSIONS: The supraorbital approach to the anterior, middle, and posterior fossae through an eyebrow incision offers a favorable rate of approach-associated surgical complications and high patient satisfaction with cosmetic outcome.

Mulitmodality management of rare solitary fibrous tumor can be associated with extended survival.

BACKGROUND: Little is known on the long-term course of patients treated for intracranial solitary fibrous tumors (iSFT). We therefore retrospectively reviewed the charts of our patients who underwent Gamma Knife radiosurgery (GKRS) for iSFT at Klinik Im Park in Zurich and who were treated by one of the authors. Between 1994 and 2009, two patients underwent GKRS for iSFT at Klinik Im Park. CASE DESCRIPTION: One patient underwent altogether five radiosurgical treatments and two craniotomies for iSFT and its local recurrences. The other patient underwent two craniotomies and one radiosurgical treatment for iSFT. Both patients maintained a Karnofsky performance score 100 during follow-up and both were long-term survivors with a follow-up of 9 and 17 years, respectively. CONCLUSION: A close follow-up of patients with iSFT and repeat radiosurgery or surgery when indicated seems to lead to a favorable long-term outcome.

Keyhole supracerebellar transtentorial transcollateral sulcus approach to the lateral ventricle.

BACKGROUND AND IMPORTANCE: Meningiomas of the lateral ventricles are commonly located in the atria. Surgical access to such tumors is challenging because of their deep location and proximity to critical neurovascular structures, particularly if situated on the dominant side. Although a number of approaches have been described in the literature, most carry the risk of postoperative neuropsychological, visual, or speech deficits, especially when operating on the dominant hemisphere. The supracerebellar transtentorial transcollateral sulcus (STTCS) approach offers the potential to circumvent functionally important structures, reducing the risk of these approach-related neurological deficits. CLINICAL PRESENTATION: Two patients with dominant hemisphere trigonal meningiomas underwent surgical resection with the use of the STTCS approach. Neuronavigation was used to carefully plan the incision, craniotomy, and exposure, and also intraoperatively to orientate the operating surgeon at key steps, particularly when raising the tentorial flap in line with the tumor. Endoscopy was used to provide increased light intensity, an extended viewing angle, and higher magnification in comparison with a microscope. Specially designed tube-shaft instruments were also used to assist with manipulation through the narrow surgical corridor. In both cases, the tumors were fully resected without approach-related morbidity. CONCLUSION: The STTCS approach provides good access to tumors located in the trigonal region, reducing the risk of iatrogenic language or visual field deficits. In dominant hemisphere lesions, in the hands of an experienced neurosurgeon, the STTCS approach is an effective alternative to existing techniques.

The keyhole concept in neurosurgery.

OBJECTIVE: Improvements in preoperative diagnostic imaging as well as in microsurgical techniques significantly advanced the development of transcranial neurosurgery, allowing the treatment of complicated diseases through smaller and more specific approaches. METHODS: In this article, authors overviewed their experience in transcranial endoscope-assisted microsurgery, using limited-sized keyhole craniotomies. Over a 10-year period, authors treated more than 3000 patients according to the transcranial endoscope-assisted microsurgery concept, advanced by the pioneer of minimally invasive neurosurgery, Axel Perneczky. RESULTS AND CONCLUSION: In all cases, meticulous preoperative planning was done for determining the site, size, and optimal placement of the craniotomy as well as the trajectory toward the surgical target. Most importantly, the surgical approach was performed either completely or at least under permanent presence of the responsible senior surgeon from the moment of patient positioning until wound closure. The minimally invasive keyhole approaches allowed safe intraoperative control and adequate dealing with intracranial lesions. Essential preconditions for keyhole surgery were 1) careful selection of cases, 2) accurate preoperative planning, 3) placement of the craniotomy tailored to the individual case, and 4) intraoperative use of transcranial endoscope-assisted microsurgery techniques. Advantages of intraoperative endoscopic visualization were increased light intensity, extended viewing angle, and clear depiction of details even in hidden parts of the surgical field.

Image-guided neurosurgery with 3-dimensional multimodal imaging data on a stereoscopic monitor.

BACKGROUND: In the past 2 decades, intraoperative navigation technology has changed preoperative and intraoperative strategies and methodology tremendously. OBJECTIVE: To report our first experiences with a stereoscopic navigation system based on multimodality-derived, patient-specific 3-dimensional (3-D) information displayed on a stereoscopic monitor and controlled by a virtual user interface. METHODS: For the planning of each case, a 3-D multimodality model was created on the Dextroscope. The 3-D model was transferred to a console in the operating room that was running Dextroscope-compatible software and included a stereoscopic LCD (liquid crystal display) monitor (DexVue). Surgery was carried out with a standard frameless navigation system (VectorVision, BrainLAB) that was linked to DexVue. Making use of the navigational space coordinates provided by the VectorVision system during surgery, we coregistered the patient's 3-D model with the actual patient in the operating room. The 3-D model could then be displayed as seen along the axis of a handheld probe or the microscope view. The DexVue data were viewed with polarizing glasses and operated via a 3-D interface controlled by a cordless mouse containing inertial sensors. The navigational value of DexVue was evaluated postoperatively with a questionnaire. A total of 39 evaluations of 21 procedures were available. RESULTS: In all 21 cases, the connection of VectorVision with DexVue worked reliably, and consistent spatial concordance of the navigational information was displayed on both systems. The questionnaires showed that in all cases the stereoscopic 3-D data were preferred for navigation. In 38 of 39 evaluations, the spatial orientation provided by the DexVue system was regarded as an improvement. In no case was there worsened spatial orientation. CONCLUSION: We consider navigating primarily with stereoscopic, 3-D multimodality data an improvement over navigating with image planes, and we believe that this technology enables a more intuitive intraoperative interpretation of the displayed navigational information and hence an easier surgical implementation of the preoperative plan.