Turcotte, Evelyn L.

BACKGROUND: Minimally invasive surgical techniques have reinvigorated the role of surgical options for spontaneous intracranial hematomas; however, they are limited by the lack of real-time feedback on the extent of hematoma evacuation. OBJECTIVE: To describe the development of a MRI-guided catheter-based aspiration system, the ClearPoint Pursuit Neuroaspiration Device (ClearPoint Neuro) and validation in phantom models. METHODS: In this preclinical experimental trial, 8 phantom brains with skull models were created to simulate an intracranial hematoma with 2 clot sizes, 30 cc (small clot) and 60 cc (large clot). After registration, the aspiration catheter (Pursuit device) was aligned to the desired planned trajectory. The aspiration of the clot was performed under real-time MRI scan in 3 orthogonal views. The primary end point was reduction of the clot volume to less than 15 cc or 70% of the original clot volume. RESULTS: Successful completion of clot evacuation was achieved in all models. The average postaspiration clot volume was 9.5 cc (8.7 cc for small clots and 10.2 cc for large clots). The average percentage reduction of clot volume was 76.3% (range 58.7%-85.2%). The average total procedure time (from frame registration to final postaspiration clot assessment) was 50 min. The average aspiration time was 6.9 min. CONCLUSION: This preclinical trial confirms the feasibility and efficacy of MRI-guided aspiration under real-time image guidance in simulation models for intracranial hematoma. Clinical use of the system in patients would further validate its efficacy and safety.

Abstract Arteriovenous malformations (AVMs) are highly complex vascular lesions characterized by abnormal connections between arteries and an intervening nidus. Definitive and safe treatment of AVMs may require the combination of multiple treatment modalities to address the various complex features of the AVM. 1 Endovascular embolization can be used as an adjuvant to surgery in order to control deep feeders, reduce flow, and address high-risk features such as aneurysms. In addition, by progressively reducing the AVM flow, staged embolization can lead to normalization of peri-AVM hemodynamics and therefore may decrease the risk of postresection hemorrhage. 2,3 In this operative video, we present a case of a 41-yr-old female who presented with progressively worsening left-sided hemiparesis. Magnetic resonance imaging (MRI) and angiography revealed a complex right fronto-parietal AVM with significant associated edema, likely due to the vascular steal phenomenon. The area of edema, which included the motor cortex, was thought to be at high risk for postoperative hemorrhage from normal perfusion pressure breakthrough. We therefore decided to proceed with staged presurgical embolization to gradually normalize the perilesional hemodynamics, and therefore possibly reduce the risk of postoperative morbidity. The patient underwent 3 embolization sessions at 6-wk intervals. An MRI after the last embolization showed near-complete resolution of the fluid-attenuated inversion-recovery (FLAIR) signal around the AVM. Microsurgical resection was performed on the day after the last embolization. The patient tolerated the procedure well and was discharged at her neurological baseline with mild contralateral hemiparesis, which has continued to improve at follow-up. Postoperative angiography showed complete resection of the AVM. The patient consented to the procedure as shown in this operative video and gave informed written consent for use of her images in publication.

Abstract Surgical approaches to lesions of the fourth ventricle (FV) have been modified over the years to reduce the complications associated with splitting the inferior cerebellar vermis (ICV) and disrupting the brainstem and critical surrounding structures. 1-4 Two common approaches to lesions of this region include the transvermian approach (TVA) and telovelar approach (TeVA). 2 The TVA was initially considered the conventional route of access to lesions of the FV 1 but has been associated with significant risks, including possible gait ataxia and dysarthria. 3 The TeVA is advantageous, as it involves dissection along natural clefts and division of non-neural tissue and provides good exposure of the superolateral recess with modest exposure of the rostral FV. The TeVA approach can be augmented by opening the tonsilouvular fissures (TUFs). This added dissection allows greater lateral and superior exposure with less need for retraction. In this operative video, we demonstrate a case in which we augmented the TeVA with a TUF dissection to access a dorsal pontine cavernous malformation. We performed a midline suboccipital craniotomy with a C1 posterior laminectomy. TUF dissection was followed by division of the tela choroidea (TC), which allowed for more lateral exposure of the FV and excellent visualization of the cavernous malformation without the need to traverse neural tissue. TeVA augmented by TUF dissection provided adequate access to the dorsal pons for complete resection of the cavernous malformation. The patient consented to the procedure as shown in this operative video and gave informed written consent for use of her images in publication. Anatomic images provided by courtesy of © The Rhoton Collection. http://rhoton.ineurodb.org/. Video © Mayo Foundation for Medical Education and Research, 2021. Used with permission.

Abstract The optic canal (OC) is a bony channel that transmits the optic nerve (ON) and ophthalmic artery (OphA) as they course through the lesser wing of the sphenoid bone to the orbital apex. The OC is involved in a variety of intracranial and extracranial pathologies, 1 and opening of the canal may be necessary in order to achieve adequate exposure, better disease control, and vision preservation. 2 Depending on the location of the pathology and its relationship with the optic nerve, the OC may be decompressed through an open transcranial approach or an endoscopic endonasal approach. 1,3 OC drilling can be tailored based on the location of the pathology and its extension. Anterior clinoid process and optic strut drilling can be added based on these factors as well. 4,5 In this video, we demonstrate the steps of OC drilling in both transcranial microscopic and endoscopic endonasal approaches through a combination of animated illustrations and operative videos. We present 4 cases, including 2 transcranial microscopic and 2 endoscopic endonasal approaches, 6 demonstrating OC decompression and its technical nuances. Each case was selected to represent the range of pathologies relevant to OC drilling to allow for a complete understanding of the techniques and concepts required for optimal treatment. An informed written consent has been obtained from each of the patients in this publication. Video © Mayo Foundation for Medical Education and Research. All rights reserved. Images at 1:03-1:10 © The Rhoton Collection. Images at 3:56-4:07 Reprinted from World Neurosurgery , vol 124, Caporlingua et al, 3 Copyright 2019, with permission from Elsevier. Images at 9:02-9:48 reprinted from Bendok et al, 6 by permission of the Congress of Neurological Surgeons.

Abstract BACKGROUND Trigeminal neuralgia (TN) refractory to medical management is often treated with microvascular decompression (MVD) involving the intracranial placement of Teflon. The placement of Teflon is an effective treatment, but does apply distributed pressure to the nerve and has been associated with pain recurrence. OBJECTIVE To report the rate of postoperative pain recurrence in TN patients who underwent MVD surgery using a transposition technique with fibrin glue without Teflon. METHODS Patients were eligible for our study if they were diagnosed with TN, did not have multiple sclerosis, and had an offending vessel that was identified and transposed with fibrin glue at our institution. All eligible patients were given a follow-up survey. We used a Kaplan-Meier (KM) model to estimate overall pain recurrence. RESULTS A total of 102 patients met inclusion criteria, of which 85 (83%) responded to our survey. Overall, 76 (89.4%) participants responded as having no pain recurrence. Approximately 1-yr pain-free KM estimates were 94.1% (n = 83), 5-yr pain-free KM estimates were 94.1% (n = 53), and 10-yr pain-free KM estimates were 83.0% (n = 23). CONCLUSION Treatment for TN with an MVD transposition technique using fibrin glue may avoid some cases of pain recurrence. The percentage of patients in our cohort who remained pain free at a maximum of 17 yr follow-up is on the high end of pain-free rates reported by MVD studies using Teflon. These results indicate that a transposition technique that emphasizes removing any compression near the trigeminal nerve root provides long-term pain-free rates for patients with TN.

Abstract Adolescent idiopathic scoliosis (AIS) is an abnormal lateral curvature of the spine that arises during the pubescent growth spurt. AIS mainly affects females in the age group of 10 to 16 yr, with a prevalence of about 1% to 3% in the at-risk population. 1 Treatment options vary depending on disease presentation and severity. Mild curvature mainly requires periodic observation for disease progression, whereas more moderate curvature can necessitate bracing or corrective surgery. 2 Here, we present the use of a temporary rod and neuroimaging for the correction of Lenke type 1 spinal curvature in an AIS patient. An inferior facetectomy is performed, and a Lenke probe is used for entry into the pedicle and vertebral body. The channel is sounded before and after tapping to check for adequate walls prior to insertion of the pedicle screw. The ARTIS pheno is brought into the field, which uses fluoroscopy to create a 3-dimensional (3D) representation of the instrumentation within the spine. A temporary rod is placed in the concavity, and a combination of corrective techniques, including a rod roll, apical translation, and reduction, is performed to bring up the concavity, derotate the spine, and translate the spine. The permanent rod is then placed in the convexity, and compression is performed to bring down the scapular prominence. The temporary rod is then removed, and a final rod is placed to complete the 3D correction. The patient consented to the procedure, and an informed written consent was obtained from the patient to use her photographs and video recordings for publication.

Cavernomas at the posterolateral pontomesencephalic surface can be approached from a lateral infratentorial supracerebellar corridor. In this surgical video, we demonstrate two cases of brainstem cavernomas resected through a lateral supracerebellar infratentorial approach. A supine position with lateral turn of the head was used along with significant reverse Trendelenburg to allow the cerebellum to fall away with gravity from the tentorium. After exposure of the posterior surface of the brainstem between the tentorium and the superior cerebellar surface with aid of neuronavigation, the cavernomas were safely resected. The video can be found here: https://youtu.be/fUDdaprg26Y .