The use of skull fixed stereotactic head frames remains an integral part of neurosurgical practice. Methods for the positioning, anesthesia, and fixation have been described in various publications. The authors describe the steps used currently that reflect a 25-year experience with stereotactic frame application. Photographs were obtained throughout the set-up and frame application process. The step-by-step methods were described with accompanying figures. Consent was obtained from that patient to allow for photographs throughout the frame application process. Consent was also obtained from a separate patient for videotaping the entire application process. Descriptive tags are embedded in the video to assist with the instruction of the senior author's (MWM) methods. The senior author has used the described method in over 1,000 cases. A recent analysis of the patient pain experience has been reported and is well tolerated. Supplemental devices beyond the manufacturers' standard equipment have been employed or developed: ethyl chloride spray, angled front posts, frame positioner, and torque wrenches. There have been no shunt perforations, no cranial vault penetrations, one titanium mesh cranioplasty deformation, three pin site infections (3 patients; 4,000 pin sites; 0.075%), and one thermal injury (0.025%). Stereotactic head frame application remains an important part of neurosurgical practice. The steps in application employed here after a 25-year experience appear to make the procedure well tolerated by patients. The authors hope this instructional article will be of value to new users who practice stereotactic radiosurgery, frame-based biopsy, depth electrode placement, or deep brain stimulator implantation.

An 86-year-old woman was admitted to the intensive care unit with a chronic subdural hematoma (CSDH) and rapid onset of worsening neurological symptoms. She was taken to the operating room for a mini-craniotomy for evacuation of the CSDH including excision of the dura and CSDH membrane. Postoperatively, a subdural evacuation port system (SEPS) was integrated into the craniotomy site and left in place rather than a traditional subdural catheter drain to evacuate the subdural space postoperatively. The patient had a good recovery and improvement of symptoms after evacuation and remained clinically well after the SEPS was removed. We offer the technique of dura and CSDH membrane excision plus SEPS drain as an effective postoperative alternative to the standard craniotomy leaving the native dura intact with traditional subdural drain that overlies the cortical surface of the brain in treating patients with CSDH.

A craniotomy over the superior cerebellar convexity for approaches to this region typically involves a small infratentorial craniotomy and then drilling down of the bone to expose some portion of the transverse/sigmoid sinuses. The authors describe the anatomy of the region and the method for a two-part paramedian occipital and suboccipital craniotomy (supra and infratentorial) that may have time-saving, safety, and cosmetic advantages. For this technique, a supratentorial craniotomy is used to expose the transverse sinus from above, and subsequently, dissection across the sinus over the cerebellar convexity can be done under direct vision. The two bone pieces are joined on the inner table side while plates for fixation above the superior nuchal line can be counter-sunk to avoid post-operative pain from the prominence of screws. There is no need for cranioplasty materials since there is no burring down of bone for adequate exposure of the transverse sinus. The technique has been used by two senior surgeons over the years convincing them of the speed, safety, and utility of the technique. Here, the authors present a single example of the technique.

We report the case of a highly vascular facline meningioma removed following surgical ligation of a large callosomarginal feeding branch via a contralateral interhemispheric approach. Successfully addressing this vessel via a contralateral interhemispheric approach prior to any debulking allowed for en bloc Simpson Grade 1 tumor removal with minimal blood loss and short term tumor control without evidence of recurrence at 2 year follow up. A 56 year old man presented with first time generalized tonic-clonic seizure. Imaging revealed a right sided 5 cm falcine meningioma. The patient underwent pre-operative embolization of feeding branches, however, the most significant supply, arising from the right callosomarginal artery, could not be occluded. A bipartite frontotemporal craniotomy was performed. From a left sided interhemispheric approach the pericallosal and callosomarginal arteries were identified and the large callosomarginal tumor feeding branch were occluded using a straight Yasargil aneurysm clip. From the right the superior sagital sinus was ligated anteriorly and posteriorly. The sinus, falx, and adherent tumor were then removed en bloc. We present the case of a highly vascular falcine meningioma with a large callosomarginal feeding branch which was successfully occluded using surgical clipping of this vessel via a contralateral interhemispheric approach. This case provides an excellent example of one approach to directly dealing with large, deep interhemispheric feeding vessels unsuitable for embolization. A 3D animation of the surgical approach is provided for instructional purposes.

Introduction  As the limits of advanced skull base malignancies that can be managed through an endoscopic endonasal approach continue to be expanded, the resultant anterior skull base defects are of increasing size and complexity. In the absence of nasoseptal or turbinate flaps, the vascularized pericranial flap has been employed at our institution with excellent results. Objective  The study aimed to review the outcomes of patients who underwent endonasal anterior craniofacial resection with anterior skull base reconstruction using a vascularized pericranial flap. Design  Retrospective chart review of patients treated by the University of California - San Francisco minimally invasive skull base service from the years 2011 to 2017. Average duration of follow-up was 16.4 months. Setting  This study was conducted at Academic tertiary referral center. Participants  A total of nine patients with advanced anterior cranial base malignancies were identified who were treated with a minimally invasive, endoscopic anterior craniofacial resection from the years 2011 to 2017. Due to the nature of the resection in these patients, nasoseptal flaps and inferior/middle turbinate flaps were unavailable or insufficient for anterior skull base defect repair. Each patient underwent reconstruction of the anterior cranial base defect using an anteriorly based pericranial flap harvested by bicoronal incision, and tunneled anteriorly to the nasal cavity through a frontoethmoidal incision.

The far lateral approach is used for accessing pathology at the craniovertebral junction but can be complicated by postoperative suboccipital muscle atrophy. In addition to significant cosmetic deformity, this atrophy can lead to head and neck pain and potentially could contribute to cranio-cervical instability. To address this issue, the senior author began using a single myocutaneous flap without a muscle cuff and securing it directly to the bone using predrilled holes in the bone that resemble a chevron. The method is described and illustrated with an example case. Results from seven consecutive cases are reported since the technique was adopted. Muscle atrophy was measured by calculating area at the level of the occipital condyle and compared with the contralateral side. No significant differences were noted. In conclusion, we have found this to be an excellent closure technique and wanted to present our initial results for consideration by other skull base surgeons.

Patients with space-occupying lesions adjacent to the superior sagittal sinus (SSS) present several technical considerations. For craniotomies crossing the SSS, a two-part method allows for dissection of the epidural space and dura under direct vision after removing a more lateral parasagittal bone flap. However, when the inner table surface of the medial component of the two-part bone flap is irregular, this can be difficult. We describe a method for channel drilling of the diploic bone, which allows for the piecemeal removal of the inner table using an upbiting rongeur. This article presents the case of meningioma with documented growth and provides a technical note of this technique to facilitate safe dissection of the midline dura. A patient presented with headaches and an anterior one-third parasagittal meningioma with documented growth. She selected surgical removal for treatment. A right frontal two-part parasagittal craniotomy was recommended. The preoperative imaging showed that the frontal bone was thick, with irregularity of the inner table. Intraoperatively, a channel was drilled in the diploic space of the bone, leaving the outer table intact. This provided a thin lip of the inner table that could be dissected over a short distance and then removed with a 2-mm upbiting rongeur. This allowed for further dissection of the dura crossing the midline under direct vision and safe secondary bone piece removal. The dura was opened to the edge of the SSS, allowing full exposure of the parasagittal region and interhemispheric fissure, thus limiting retraction of the medial right frontal lobe. The bone flap was removed in two pieces without a dural tear over the midline in spite of inner table irregularities. A Simpson grade 1 removal was accomplished, including excision of the affected falx, and the postoperative course was uncomplicated. In conclusion, diploic bone channel drilling is a technique that can be used to create a thin lip of the inner table, which can be removed piecemeal for safe dissection of the midline dura crossing the midline.

Background

Providing the standard of care to patients with glioblastoma (GBM) during the novel coronavirus of 2019 (COVID-19) pandemic is a challenge, particularly if a patient tests positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Further difficulties occur in eloquent cortex tumors because awake speech mapping can theoretically aerosolize viral particles and expose staff. Moreover, microscopic neurosurgery has become difficult because the use of airborne-level personal protective equipment (PPE) crowds the space between the surgeon and the eyepiece. However, delivering substandard care will inevitably lead to disease progression and poor outcomes.

Observations

A 60-year-old man with a left insular and frontal operculum GBM was found to be COVID-19 positive. Treatment was postponed pending a negative SARS-CoV-2 result, but in the interim, he developed intratumoral hemorrhage with progressive expressive aphasia. Because the tumor was causing dominant hemisphere language symptomatology, an awake craniotomy was the recommended surgical approach. With the use of airborne-level PPE and a surgical drape to protect the surgeon from the direction of potential aerosolization, near-total gross resection was achieved.

Lessons

Delaying the treatment of patients with GBM who test positive for COVID-19 will lead to further neurological deterioration. Optimal and timely treatment such as awake speech mapping for COVID-19-positive patients with GBM can be provided safely.

A feared complication of ventricular access for drainage or shunting is ventriculitis. Early diagnosis and treatment is vital to prevent morbidity and mortality. Efficacy of directed antibiotic therapy in ventriculitis is limited by increasing multidrug resistant microorganisms and insufficient systemic antibiotic absorption into the cerebrospinal fluid. Treatment may involve intravenous and/or intrathecal antibiotics as well as external ventricular drainage. We present the first case report suggesting a potential role of a novel technique - direct ventricular catheter-mediated continuous saline irrigation and serial prone patient positioning - to treat a fulminant bacterial ventriculitis. This novel technique promotes egress of purulence from the ventricles and may result in more rapid control of intraventricular infectious burden.

Tuberculum sellae meningiomas frequently produce visual loss by direct compression from tumor, constriction of the optic nerve (ON) under the falciform ligament, and/or ON ischemia. The authors hypothesized that changes in visual function after tumor removal may be related to changes in blood supply to the ON that might be seen in the pial circulation at surgery. Indocyanine green (ICG) angiography was used to attempt to document these changes at surgery. The first patient in whom the technique was used had a left-sided, 1.4-cm, tuberculum meningioma. Time-lapse comparison of images was done postsurgery, and the comparison of video images revealed both faster initial filling and earlier complete filling of the ON pial circulation, suggesting improved pial blood flow after surgical decompression. In follow-up the patient had significant improvements in both visual acuity and visual fields function. Intraoperative ICG angiography of the ON can demonstrate measurable changes in pial vascular flow that may be predictive of postoperative visual outcome. The predictive value of this technique during neurosurgical procedures around the optic apparatus warrants further investigation in a larger cohort.