Endoscope-assisted resection of calcified thoracic disc herniations.

PURPOSE: Resection of calcified thoracic disc herniations carries significant risks of neurological worsening, particularly in case of concomitant central location. Transthoracic approaches are a first-choice option to avoid spinal cord manipulation but entail drawbacks such as postoperative pain and the risk of bronchopulmonary complications. The purpose of this report is to describe a novel approach to resect calcified herniations, even centrally located, from a posterior perspective. METHODS: Unilateral lamino-arthrectomy is performed, uncovering few millimeters of the disc space beside the dura. Following discectomy and drilling of the vertebral endplates, an angled endoscope is introduced allowing resection of the calcified herniation through an anterior perspective. The spinal cord can now be decompressed with a no-touch technique. Each maneuver aimed at resecting the calcified mass up to the contralateral side can be done under visual control. RESULTS: The technique was used in two patients. The first was a 38-year-old man with a calcified mediolateral T9-T10 disc herniation and mild myelopathic symptoms. The second patient was a 73-year-old obese woman, with a T6-T7 central, calcified disc herniation and severe compression myelopathy. In both cases, complete decompression of the spinal cord could be achieved and rapid neurological recovery was observed postoperatively. No surgery-related complications were observed. CONCLUSIONS: The endoscope-assisted posterior approach afforded safe and complete resection of calcified discs. The technique is particularly useful for central disc herniations, where transthoracic approaches are normally deemed mandatory.

Can exoscope improve brain AVMs surgery?

The advantages of the surgical view provided by the exoscope have been described before, although reports of its application to brain arteriovenous malformation (AVM) surgery are lacking. The ampler field of view and magnification up to ×24 allow for enhanced visualization during microsurgical procedures. Furthermore, the live visualization provided by indocyanine green video angiography (ICG-VA) helps emphasize the hemodynamics of AVMs, even allowing the detection of possible residual vein arterialization as an indirect expression of nidal remnants. With this illustrative video showing the resection of a hemorrhagic right frontoinsular Spetzler-Martin grade III AVM, the authors describe the technical implications of exoscope brain AVM surgery using the Olympus ORBEYE 4K-3D, with a final focus on ICG-VA as an asset. The video can be found here: https://stream.cadmore.media/r10.3171/2023.10.FOCVID23114.

Temporal lobe tumors modify local venous drainage.

OBJECTIVE: Superficial Middle Cerebral Vein (SMCV) is an anastomotic vein frequently exposed during surgery. Changes in the pattern of cerebral venous outflow can occur in many pathological settings. We explored the hypothesis that the growth of an intracranial tumor could determine alterations in the venous outflow. We analyzed SMCV anatomical variants in patients undergoing surgery for intracranial tumors; we furthermore focused on association with histology. METHODS: We retrospectively collected data of 120 patients undergoing surgery, 60 presenting intracranial tumor and 60 presenting cerebral aneurysms (control group). Tumor series was divided into "Low Growth-Rate tumors" (WHO grade I and II) and "High Growth-Rate tumors" (WHO grade III and IV). Anatomical variants of SMCV were analyzed on intraoperative videos and then classified as Type 1 (normotrophic), 2 A (hypotrophic) and Type 2B (absent/atrophic). We furthermore defined as Type 2 any alteration of the SMCV (2 A+2B) encountered. Relationships among SMCV types and both populations were analyzed using the chi-squared test; values of p < 0.05 were considered statistically significant. RESULTS: We found a positive correlation between the presence of a primary brain tumor and Type 2B SMCV (PC.004, p < 0.05) and Type 2 SMCV (PC.000, p < 0.05). Specifically, we found a strong correlation between the absence of SMCV (Type 2B) and both tumors subgroups. Thus, the growth of a primary brain tumor seems to affect the cerebral local outflow. CONCLUSIONS: Primary brain tumors seem to alter local venous network of SMCV. Clinical and oncological implications remain subject of further investigation.

Intraoperative Mapping of the Sensory Root of the Trigeminal Nerve in Patients with Pontocerebellar Angle Pathology.

OBJECTIVE: The aim of the present study was to determine the position of the 3 sensory branches of the trigeminal nerve in the preganglionic tract using intraoperative neurophysiological mapping. METHODS: We included consecutive adult patients who underwent neurosurgical treatment of cerebellopontine angle lesions. The trigeminal nerve was antidromically stimulated at 3 sites along its circumference with different stimulus intensities at a distance of ≤1 cm from the brainstem. The sensory nerve action potentials (SNAPs) were recorded from each main trigeminal branch (V1 [ophthalmic branch], V2 [maxillary branch], and V3 [mandibular branch]). RESULTS: We analyzed 13 patients. The stimulation points at which we obtained the greatest number of congruous and exclusive SNAPs (SNAPs only on the stimulated branch) was the stimulation point for V3 (20.7%). The stimulation intensity at which we obtained the highest number of congruent and exclusive SNAPs with the stimulated branch was 0.5 mA. CONCLUSIONS: Using our recording conditions, trigeminal stimulation is a reliable technique for mapping the V3 and V1 branches using an intensity not exceeding 0.5. However, reliable identification of the fibers of V2 is more difficult. Stimulation of the trigeminal nerve can be a reliable technique to identify the V3 and V1 branches if rhizotomy of these branches is necessary.

Feasibility of Intraoperative Visual Evoked Potential Monitoring by Cortical Strip Electrodes in Patients During Brain Surgery: A Preliminary Study.

OBJECTIVE: The role of visual evoked potentials (VEPs) monitoring during neurosurgical procedure in patient remains unclear. The purpose of our study was to determine the feasibility of intraoperative VEP recording using a strip cortical electrode during surgical resection of intracranial lesions. METHODS: In this prospective, monocentric, observational study, we enrolled consecutive patients undergoing neurosurgical procedure for intracranial lesions. After dural opening, a cortical strip was positioned on the lateral occipital surface. Flash VEPs were continuously recorded using both subdermal corkscrew electrodes and strip electrodes. An electroretinogram was also recorded to guarantee delivery of adequate flash stimuli to the retina. RESULTS: We included 10 patients affected by different intracranial lesions. Flash VEPs were recorded using subdermal corkscrew electrodes in all patients except 1 in whom they were never identified during the recording. Flash VEPs were recorded using strip electrodes in all patients and showed a polyphasic morphology with a significantly larger amplitude compared with that of flash VEPs measured using subdermal corkscrew electrodes. No patient reported worsened postoperative vision and a >50% decrease in the VEPs amplitude was never registered. CONCLUSIONS: We have reported for the first time in the literature that VEP monitoring during a neurosurgical procedure is feasible via a cortical strip located on the occipital surface. The technique demonstrated greater stability and a larger amplitude compared with recordings with scalp electrodes, facilitating identification of any changes. Studies with more patients are needed to assess the clinical reliability of the technique.

Extradural arteriovenous fistulas involving the vertebral artery in neurofibromatosis Type 1.

Spinal extradural arteriovenous fistulas (AVFs) are rare lesions that may be associated with neurofibromatosis Type 1 (NF1). In these patients, the shunt typically occurs between the V(2) segment of the vertebral artery and the epidural venous plexus. Previously, reported cases have been treated either by using endovascular embolization or, sporadically, by open surgery. In surgical reports, proximal deafferentation or manipulation of the venous portion of the shunt--including suture, resection, or open embolization of the epidural ectasia--was attempted with variable results. The authors report on a case of a young patient with NF1 who underwent emergency surgical disconnection of a cervical extradural AVF after previously unsuccessful endovascular and surgical therapy. The lesion drained into a giant intrathecal varix, causing severe myelopathy. After surgery, the patient recovered almost completely. This experience clarified the surgical anatomy of these malformations and showed that, when surgery is necessary, the optimal treatment providing complete and permanent cure of this condition is direct closure of the epidural shunt pedicle.

Symptomatic Spinal Cord Bending After Meningioma Resection: A Technical Case Report.

Resection of intradural tumors is often followed by bending of the spinal cord within the surgical cave. This event is known to be innocuous. The authors report a case where the position assumed by the spinal cord at the end of surgery was associated with significant motor evoked potential decline. The patient, a 44-year-old woman with a meningioma of the craniocervical junction, underwent tumor resection aided by intraoperative neurophysiological monitoring. At the time of dural closure, the motor evoked potentials were completely lost on the left side and reduced on the right side. Intraoperative maneuvers showed that worsening was related to the spinal cord position. Motor evoked potentials were restored by tethering the cord posteriorly, back to its original site. This report underlines the usefulness of maintaining intraoperative monitoring until the end of surgery and provides a technical nuance to manage a rare complication.

Emergency decompressive craniectomy after removal of convexity meningiomas.

BACKGROUND: Convexity meningiomas are benign brain tumors that are amenable to complete surgical resection and are associated with a low complication rate. The aim of this study was to identify factors that result in acute postoperative neurological worsening after the removal of convexity meningiomas. METHODS: Clinical evaluation and neuroradiological analysis of patients who underwent removal of a supratentorial convexity meningioma were reviewed. Patients were selected when their postoperative course was complicated by acute neurological deterioration requiring decompressive craniectomy. RESULTS: Six patients (mean age: 43.3 years) underwent surgical removal of a supratentorial convexity meningioma. Brain shift (mean: 9.9 mm) was evident on preoperative imaging due to lesions of varying size and perilesional edema. At various times postoperatively, patient consciousness worsened (up to decerebrate posture) with contralateral paresis and pupillary anisocoria. Computed tomography revealed no postoperative hematoma, however, did indicate increased brain edema and ventricular shift (mean: 12 mm). Emergency decompressive craniectomy and brief ventilator assistance were performed in all patients. Ischemia of the ipsilateral posterior cerebral artery occurred in 3 patients and hydrocephalus occurred in 2 patients. Outcome was good in 2, fair in 2, 1 patient had severe disability, and 1 patient died after 8 months. CONCLUSIONS: Brain shift on preoperative imaging is a substantial risk factor for postoperative neurological worsening in young adult patients after the removal of convexity meningiomas. Emergency decompressive craniectomy must be considered because it is effective in most cases. Other than consciousness impairment, there is no reliable clinical landmark to guide the decision to perform decompressive craniectomy; however, brain ischemia may have already occurred.

Sacral Tarlov cyst: surgical treatment by clipping.

BACKGROUND: This study reports the anatomopathological classification of Tarlov cysts and the various treatment techniques described in the literature. METHODS: The authors present their patient series (19 cases) with a long follow-up (range 9 months to 25 years) treated by cyst remodeling around the root using titanium clips. RESULTS: The technique is effective in both avoiding cerebrospinal fluid leakage and resolving bladder dysfunction when urinary symptoms are incomplete and discontinuous. CONCLUSIONS: The clipping technique for Tarlov cysts is easy, valid, safe, rapid, and effective.

En plaque sphenoid wing meningiomas: recurrence factors and surgical strategy in a series of 71 patients.

OBJECTIVE: En plaque sphenoid wing meningiomas are complex tumors involving the sphenoid wing, the orbit, and sometimes the cavernous sinus. Complete removal is difficult, so these tumors have high rates of recurrence and postoperative morbidity. The authors report a series of 71 patients with sphenoid wing meningiomas that were managed surgically. METHODS: The clinical records of 71 consecutive patients undergoing surgery for sphenoid wing meningiomas at Lariboisière Hospital, Paris, were prospectively collected in a database during a 20-year period and analyzed for presenting symptoms, surgical technique, clinical outcome, and follow-up. RESULTS: Among the 71 patients (mean age, 52. 7 years; range, 12-79 years), 62 were females and 9 were males. The most typical symptoms recorded were proptosis in 61 patients (85.9%), visual impairment in 41 patients (57.7%), and oculomotor paresis in 9 patients (12.7%). Complete removal was achieved in 59 patients (83%). At 6 months of follow-up, magnetic resonance imaging scans revealed residual tumor in 12 patients (9 in the cavernous sinus and 3 around the superior orbital fissure). Mean follow-up was 76.8 months (range, 12-168 months). Tumor recurrence was recorded in 3 of 59 patients (5%) with total macroscopic removal. Among the patients with subtotal resection, tumor progression was observed in 3 of 12 patients (25%; 2 patients with grade III and 1 patient with grade IV resection). Mean time to recurrence was 43.3 months (range, 32-53 months). CONCLUSION: Surgical management of patients with sphenoid wing meningiomas cannot be uniform; it must be tailored on a case-by-case basis. Successful resection requires extensive intra- and extradural surgery. We recommend optic canal decompression in all patients to ameliorate and/or preserve visual function.