Spontaneous cerebrospinal fluid leaks of the temporal bone - clinical features and management outcomes.

OBJECTIVE: METHODS: A retrospective cohort study over seven-years from 2013 to 2020 was conducted at five tertiary referral centres. Patients identified with biochemically confirmed spontaneous cerebrospinal fluid leaks of the temporal bone manifesting as middle ear fluid with no other obvious cause were included. Demographics (age, gender, body-mass-index), symptomatology, past medical history, examination, investigation (biochemical and radiological), management and outcomes were recorded. RESULTS: 90 adult patients with spontaneous cerebrospinal fluid otorrhoea were identified. Right sided leaks were most common (58%), and a majority of the cohort overweight (mean body-mass-index = 29.2 kg/m2). Unilateral hearing loss was the commonest presenting symptom (81%). Two patients presented to hospital with meningitis presumed secondary to spontaneous cerebrospinal fluid otorrhoea. Over half (54%) of patients were observed who tended to be older (mean age of 71 years vs 62 years) whilst the remainder underwent surgical repair with middle-fossa craniotomy the most common approach (87%). Eight patients managed surgically had recurrent leaks (21%). CONCLUSIONS: This is one of the largest cohorts of spontaneous cerebrospinal fluid otorrhoea reported in the literature and reiterates the importance for clinicians to have a high index of suspicion for this condition in patients presenting with a unilateral middle ear effusion, especially in those who are overweight. Surgical intervention carries a risk of recurrence and further studies are needed to determine the risk of intra-cranial infection in order to guide management.

Endonasal endoscopic resection of suprasellar craniopharyngioma: A retrospective single-center case series.

INTRODUCTION: Endoscopic endonasal approach (EEA) has recently been proposed as an option for resection of primary and recurrent suprasellar craniopharyngioma. However, surgical outcome has not yet been fully evaluated, especially in regards to recurrent cases. METHODS: We analysed our institution (Sir Charles Gairdner University Hospital, Perth, Australia) case-series retrospectively. There were 16 patients operated through an endonasal endoscopic approach from February 2014 to February 2019 for suprasellar craniopharyngiomas. There were 14 primary, and two recurrent lesions. Extent of resection, complications, visual and endocrinological outcomes are presented. RESULTS: Mean age of the patients was 42.9 ± 19.3 years old, with 56% female. The most common clinical symptoms were headaches (9 patients, 56%) and bi-temporal hemianopsia (9 patients, 56%), followed by unilateral optic neuropathy (5 cases, 31%), memory loss (1 case, 6%), hydrocephalus (1 case, 6%), delayed growth and puberty (1 case, 6%), and secondary amenorrhoea (1 case, 6%). Only two cases (12%) initially presented with normal visual function. Gross total resection (GTR) was achieved in 10/16 patients (62.5%), with subtotal resection (STR) in the remainder. Visual symptoms improved in 13/16 patients (81%) and remained unchanged in 3/16 patients (19%). Most common complications included new endocrinological deficit in nine patients (56%), mostly diabetes insipidus, and cerebrospinal fluid leak requiring a new intervention in three patients (19%). There was one mortality case (complicated meningitis, stroke and vasospasm). Mean follow-up time was 22.05 ± 14 months and three patients (19%) had a recurrence of the disease during this period and were referred for radiation therapy. CONCLUSION: Endonasal endoscopic approach is a safe and effective surgical option for both primary and recurrent suprasellar craniopharyngiomas.

Modulation of saccades in humans by electrical stimulation of the posterior subthalamic area.

OBJECTIVE: Posterior subthalamic area (PSA) deep brain stimulation (DBS) targeting the zona incerta (ZI) is an emerging treatment for tremor syndromes, including Parkinson's disease (PD) and essential tremor (ET). Evidence from animal studies has indicated that the ZI may play a role in saccadic eye movements via pathways between the ZI and superior colliculus (incerto-collicular pathways). PSA DBS permitted testing this hypothesis in humans. METHODS: Sixteen patients (12 with PD and 4 with ET) underwent DBS using the MRI-directed implantable guide tube technique. Active electrode positions were confirmed at the caudal ZI. Eye movements were tested using direct current electrooculography (EOG) in the medicated state pre- and postoperatively on a horizontal predictive task subtending 30°. Postoperative assessments consisted of stimulation-off, constituting a microlesion (ML) condition, and high-frequency stimulation (HFS; frequency = 130 Hz) up to 3 V. RESULTS: With PSA HFS, the first saccade amplitude was significantly reduced by 10.4% (95% CI 8.68%-12.2%) and 12.6% (95% CI 10.0%-15.9%) in the PD and ET groups, respectively. With HFS, peak velocity was reduced by 14.7% (95% CI 11.7%-17.6%) in the PD group and 27.7% (95% CI 23.7%-31.7%) in the ET group. HFS led to PD patients performing 21% (95% CI 16%-26%) and ET patients 31% (95% CI 19%-38%) more saccadic steps to reach the target. CONCLUSIONS: PSA DBS in patients with PD and ET leads to hypometric, slowed saccades with an increase in the number of steps taken to reach the target. These effects contrast with the saccadometric findings observed with subthalamic nucleus DBS. Given the location of the active contacts, incerto-collicular pathways are likely responsible. Whether the acute finding of saccadic impairment persists with chronic PSA stimulation is unknown.

Single-Piece Titanium Plate Cranioplasty Reconstruction of Complex Defects.

BACKGROUND: Different methods have been described for the reconstruction of cranial defects and orbital defects. The complex contouring between the orbital roof and frontal bone creates significant design challenges for prefabricated cranio-orbital reconstructions. In describing the first reported patient of combined skull and orbital roof reconstruction with a single-piece titanium plate cranioplasty, the authors present a new method of combined complex cranio-orbital reconstruction. METHODS: A 63-year-old lady presented with a large, right-sided frontal en-plaque meningioma involving the right orbit and sphenoid wing. Complete resection would require reconstruction of both the skull and the orbital roof. Surgical preplanning involved marking resection margins on a three-dimensional (3D) printed acrylonitrile-butadiene-styrene model. This margin was used to virtually resect the tumor and generate a repaired surface. A titanium plate was then fabricated using hydrostatic pressing into a 3D-printed mold and the orbital roof portion (a reentrant surface) was hand-finished. Lateral canthus and temporalis muscle suspension holes were prefabricated into the cranioplasty plate. RESULTS: The patient underwent hemicraniectomy and tumor resection guided by a custom-made 3D-printed cutting guide. The surgical defect was reconstructed with the prefabricated titanium plate achieving a good functional and cosmetic result. CONCLUSION: Single-piece titanium plate cranioplasty is an effective novel reconstruction method for complex cranio-orbital defects.

Spinal subarachnoid hemorrhage secondary to rupture of an isolated radicular artery aneurysm.

Aneurysmal subarachnoid hemorrhage (aSAH) of spinal origin is an uncommon entity and comprises less than 1% of all aSAH. The paucity of clinical cases creates challenges to its diagnosis and management. We present the case of a 58-year-old male, who presented with a spinal subarachnoid hemorrhage secondary to a de novo spinal radicular artery aneurysm. Spinal subarachnoid hemorrhages typically occur secondary to arteriovenous malformations or arterial wall weakness seen in collagen vascular disease. Fewer than 20 cases of isolated spinal arterial aneurysms have been published. SAHs of spinal origin are exceedingly rare and thus a high index of suspicion is required for an accurate and timely diagnosis.

Retinal vein pulsation is in phase with intracranial pressure and not intraocular pressure.

PURPOSE: As efforts to noninvasively measure intracranial pressure (ICP) increase, we thought it important to investigate the timing of retinal venous pulsation in relation to the intraocular and intracranial pressure pulses. METHODS: Neurosurgical patients undergoing continuous direct ICP monitoring had video recordings of ICP, IOP, and retinal venous pulsation waveforms taken with constant timing relative to the cardiac cycle using pulse oximetry. Video frames of the maxima and minima of these parameters, including retinal vein diameter, were identified. The times from pulse oximetry "beep" to these parameters were measured and converted into a percentage of the respective cardiac cycle. RESULTS: A total of 338 measurements from nine subjects with a mean age of 39 years, mean ICP of 4.4 mm Hg and IOP 15.1 mm Hg were taken. Vein diameter minima occurred an insignificant 0.6% of cardiac cycle before ICP minima (P = 0.6620) and a significant 3.2% after IOP minima (P = 0.0097) and significantly later than IOP (51%) and ICP maxima (74%, all P < 0.0001). Maximum vein diameter occurred an insignificant 2.0% before IOP maxima (P = 0.2267) and was significantly different from IOP and ICP minima (P < 0.00001). Mean venous pulsation pressure between the two eyes was significantly associated with ICP (r = 0.89, P = 0.0075). CONCLUSIONS: During pulsation, central retinal vein collapse occurs in time with IOP and ICP diastole. Venous collapse is not induced by intraocular systole. These results suggest that ICP pulse pressure dominates the timing of venous pulsation.

Accuracy of magnetic resonance imaging-directed frame-based stereotaxis.

BACKGROUND: Accurate placement of a probe to the deep regions of the brain is an important part of neurosurgery. In the modern era, magnetic resonance image (MRI)-based target planning with frame-based stereotaxis is the most common technique. OBJECTIVE: To quantify the inaccuracy in MRI-guided frame-based stereotaxis and to assess the relative contributions of frame movements and MRI distortion. METHODS: The MRI-directed implantable guide-tube technique was used to place carbothane stylettes before implantation of the deep brain stimulation electrodes. The coordinates of target, dural entry point, and other brain landmarks were compared between preoperative and intraoperative MRIs to determine the inaccuracy. RESULTS: The mean 3-dimensional inaccuracy of the stylette at the target was 1.8 mm (95% confidence interval [CI], 1.5-2.1. In deep brain stimulation surgery, the accuracy in the x and y (axial) planes is important; the mean axial inaccuracy was 1.4 mm (95% CI, 1.1-1.8). The maximal mean deviation of the head frame compared with brain over 24.1 ± 1.8 hours was 0.9 mm (95% CI, 0.5-1.1). The mean 3-dimensional inaccuracy of the dural entry point of the stylette was 1.8 mm (95% CI, 1.5-2.1), which is identical to that of the target. CONCLUSION: Stylette positions did deviate from the plan, albeit by 1.4 mm in the axial plane and 1.8 mm in 3-dimensional space. There was no difference between the accuracies at the dura and the target approximately 70 mm deep in the brain, suggesting potential feasibility for accurate planning along the whole trajectory.

Accuracy of postoperative computed tomography and magnetic resonance image fusion for assessing deep brain stimulation electrodes.

BACKGROUND: Knowledge of the anatomic location of the deep brain stimulation (DBS) electrode in the brain is essential in quality control and judicious selection of stimulation parameters. Postoperative computed tomography (CT) imaging coregistered with preoperative magnetic resonance imaging (MRI) is commonly used to document the electrode location safely. The accuracy of this method, however, depends on many factors, including the quality of the source images, the area of signal artifact created by the DBS lead, and the fusion algorithm. OBJECTIVE: To calculate the accuracy of determining the location of active contacts of the DBS electrode by coregistering postoperative CT image to intraoperative MRI. METHODS: Intraoperative MRI with a surrogate marker (carbothane stylette) was digitally coregistered with postoperative CT with DBS electrodes in 8 consecutive patients. The location of the active contact of the DBS electrode was calculated in the stereotactic frame space, and the discrepancy between the 2 images was assessed. RESULTS: The carbothane stylette significantly reduces the signal void on the MRI to a mean diameter of 1.4 ± 0.1 mm. The discrepancy between the CT and MRI coregistration in assessing the active contact location of the DBS lead is 1.6 ± 0.2 mm, P < .001 with iPlan (BrainLab AG, Erlangen, Germany) and 1.5 ± 0.2 mm, P < .001 with Framelink (Medtronic, Minneapolis, Minnesota) software. CONCLUSION: CT/MRI coregistration is an acceptable method of identifying the anatomic location of DBS electrode and active contacts.

High-frequency pallidal stimulation for camptocormia in Parkinson disease: case report.

BACKGROUND AND IMPORTANCE: Camptocormia is characterized by abnormal flexion of the thoracolumbar spine that increases during upright posture and abates in the recumbent position and has been reported to occur in patients with Parkinson disease. Camptocormia causes significant spinal and abdominal pain, impairment of balance, and social stigma. CLINICAL PRESENTATION: A 57-year-old woman with Parkinson disease developed severe camptocormia, which did not improve with trials of antiparkinsonian and muscle relaxant medications. The patient was successfully treated with bilateral globus pallidus interna deep brain stimulation surgery under general anesthesia. High-frequency neuromodulation afforded relief of camptocormia and improvement in Parkinson disease symptoms. CONCLUSION: Camptocormia in Parkinson disease may represent a form of dystonia and can be treated effectively with chronic pallidal neuromodulation.

Does remote ischemic preconditioning prevent delayed hippocampal neuronal death following transient global cerebral ischemia in rats?

OBJECTIVE: To determine if remote ischemic preconditioning (RIPC) induced by transient limb ischemia is protective against delayed hippocampal neuronal death in rats undergoing transient global cerebral ischemia (GCI). METHOD: Animals were randomized into 3 groups: Group I (Control, n = 5) underwent sham procedure, namely, general anesthesia x 2, without cerebral ischemia; Group II (RIPC + GCI, n = 5) was subjected to RIPC, induced by transient left hind limb ischemia under general anesthesia prior to GCI; Group III (GCI only, n = 5) underwent sham procedure under general anesthesia prior to GCI. Twenty-four hours after the RIPC or sham procedure, a transient GCI was induced for 8 minutes in Groups II and III by means of bilateral common carotid artery occlusion and hypotension. Hippocampal CA1 neurons were histologically examined at 7 days after ischemia. RESULTS: There was no significant difference between the RIPC group and the ischemia only group. The number of neurons in the RIPC group were 0.90 (95% CI 0.20, 4.08) times the number in the ischemia group (p=0.89). The number of neurons in the RIPC group were 0.03 (95% CI 0.01, 0.10) times the number in the Control group (p=0.0001). CONCLUSION: Second window of the RIPC does not prevent hippocampal CA1 neuronal death at 7 days after transient global cerebral ischemia.

Spinal chondromyxoid fibroma of C2.

Chondromyxoid fibroma of bone (CMF) is a rare benign primary bone neoplasm accounting for less than 0.5% of all primary bone neoplasms. The spine is an uncommon site for this tumour, with forty-two cases reported in the modern English literature. They have clinical features similar to CMF arising at other sites. Local recurrence is well documented. We report an incidentally discovered lytic lesion of the C2 vertebra. The patient underwent stereotactic CT guided trans-oral curettage of the lesion with iliac bone graft and anterior fusion of C2 and C3. Microscopic examination of the surgical specimen demonstrated CMF. This is the second reported case of this rare tumour in this location. We review the literature and the unique radiological and pathological features and management of spinal CMF. Local recurrence of spinal CMF and its management is also discussed in light of the five previously reported cases of local spinal recurrence.