Avoiding the Radial Paradox: Neuroendovascular Femoral Access Outcomes After Radial Access Adoption.

BACKGROUND: Transradial access (TRA) for neuroendovascular procedures is increasing in prevalence. The safety benefits of TRA at a patient level may be offset at a population level by a paradoxical increase in transfemoral access (TFA) vascular access site complications (VASCs), the so-called "radial paradox." OBJECTIVE: To study the effect of TRA adoption on TFA performance and outcomes in neuroendovascular procedures. METHODS: Data were collected for all procedures performed over a 10-mo period after radial adoption at a single center. RESULTS: Over the study period, 1084 procedures were performed, including 719 (66.3%) with an intent to treat by TRA and 365 (33.7%) with an intent to treat by TFA. Thirty-two cases (4.4%) crossed over from TRA to TFA, and 2 cases (0.5%) crossed over from TFA to TRA. TFA was performed in older patients (mean [standard deviation] TFA, 63 [15] vs TRA, 56 [16] years) using larger sheath sizes (≥7 French; TFA, 56.2% vs TRA, 2.3%) ( P < .001 for both comparisons). Overall, 29 VASCs occurred (2.7%), including 27 minor (TFA, 4.6% [18/395] vs TRA, 1.3% [9/689], P = .002) and 2 major (TFA, 0.3% [1/395] vs TRA, 0.1% [1/689], P > .99) complications. Independent predictors of VASC included TFA (OR 2.8, 95% confidence interval [CI] 1.1-7.4) and use of dual antiplatelet therapy (OR 4.2, 95% CI 1.6-11.1). CONCLUSION: TFA remains an important access route, despite a predominantly radial paradigm, and is disproportionately used in patients at increased risk for VASCs. TFA proficiency may still be achieved in predominantly radial practices without an increase in femoral complications.

Transradial cerebral angiography becomes more efficient than transfemoral angiography: lessons from 500 consecutive angiograms.

BACKGROUND: Transradial arterial access (TRA) for cerebral diagnostic angiography is associated with fewer access site complications than transfemoral access (TFA). However, concerns about increased procedure time and radiation exposure with TRA may slow its adoption. Our objective was to measure TRA rates of success and fluoroscopy time per vessel after 'radial-first' adoption and to compare these rates to those obtained with TFA. METHODS: We examined 500 consecutive cerebral angiograms on an intent-to-treat basis during the first full year of radial-first adoption, recording patient and procedural characteristics and outcomes. RESULTS: Over a 9-month period at a single center, 457 of 500 angiograms (91.4%) were performed with intent-to-treat via TRA, and 431 cases (86.2%) were ultimately performed via TRA. One patient (0.2%) experienced a temporary neurologic deficit in the TRA group, and none (0%) did in the TFA group (p=0.80). The mean±SD fluoroscopy time per vessel decreased significantly from the first half of the study to the second half for TRA (5.0±3.8 vs 3.4±3.5 min/vessel; p<0.001), while TFA time remained unchanged (3.7±1.8 vs 3.5±1.4 min/vessel; p=0.69). The median fluoroscopy time per vessel for TRA became faster than that for TFA after 150 angiograms. CONCLUSION: Of 500 consecutive angiograms performed during the first full year of radial-first implementation, 86.2% were performed successfully using TRA. TRA efficiency exceeded that of TFA after 150 angiograms. Concerns about the length of procedure or radiation exposure should not be barriers to TRA adoption.

Percutaneous transorbital direct puncture to obliterate a cavernous sinus dural arteriovenous fistula.

Cavernous sinus dural arteriovenous fistulas (CS-DAVF) can have an indolent course, with insidious onset, but still showing a high likelihood of spontaneous resolution.1 Nevertheless, symptoms in a subset of patients evolve more rapidly, with malignant signs on imaging, warranting intervention.2 We report on a patient in his 40s presenting with redness and proptosis of the right eye, intermittent blurred vision and diplopia. Once ophthalmological examination revealed increased intraocular pressure and imaging showed cortical venous congestion, the decision was made to obliterate a CS-DAVF involving the posteromedial right cavernous sinus.Multiple arteries including branches of the ascending pharyngeal artery, occipital artery and bilateral meningohypophyseal trunks supplied the fistula. Once transarterial embolization was deemed unsafe and both inferior petrosal sinuses did not grant access to the right cavernous sinus, a direct puncture to the cavernous sinus was performed to successfully coil the involved compartments.3-5 The aid of DynaCT imaging and needle guidance software is emphasized (video 1). neurintsurg;13/12/1190/V1F1V1Video 1.

A propensity-adjusted comparison of middle meningeal artery embolization versus conventional therapy for chronic subdural hematomas.

OBJECTIVE: Middle meningeal artery (MMA) embolization is a promising treatment strategy for chronic subdural hematomas (cSDHs). However, studies comparing MMA embolization and conventional therapy (surgical intervention and conservative management) are limited. The authors aimed to compare MMA embolization versus conventional therapy for cSDHs using a propensity-adjusted analysis. METHODS: A retrospective study of all patients with cSDH who presented to a large tertiary center over a 2-year period was performed. MMA embolization was compared with surgical intervention and conservative management. Neurological outcome was assessed using the modified Rankin Scale (mRS). A propensity-adjusted analysis compared MMA embolization versus surgery and conservative management for all individual cSDHs. Primary outcomes included change in hematoma diameter, treatment failure, and complete resolution at last follow-up. RESULTS: A total of 231 patients with cSDH met the inclusion criteria. Of these, 35 (15%) were treated using MMA embolization, and 196 (85%) were treated with conventional treatment. On the latest follow-up, there were no statistically significant differences between groups in the percentage of patients with worsening mRS scores. Of the 323 total cSDHs found in 231 patients, 41 (13%) were treated with MMA embolization, 159 (49%) were treated conservatively, and 123 (38%) were treated with surgical evacuation. After propensity adjustment, both surgery (OR 12, 95% CI 1.5-90; p = 0.02) and conservative therapy (OR 13, 95% CI 1.7-99; p = 0.01) were predictors of treatment failure and incomplete resolution on follow-up imaging (OR 6.1, 95% CI 2.8-13; p < 0.001 and OR 5.4, 95% CI 2.5-12; p < 0.001, respectively) when compared with MMA embolization. Additionally, MMA embolization was associated with a significant decrease in cSDH diameter on follow-up relative to conservative management (mean -8.3 mm, 95% CI -10.4 to -6.3 mm, p < 0.001). CONCLUSIONS: This propensity-adjusted analysis suggests that MMA embolization for cSDH is associated with a greater extent of hematoma volume reduction with fewer treatment failures than conventional therapy.

Propensity-Adjusted Comparative Analysis of Radial Versus Femoral Access for Neurointerventional Treatments.

BACKGROUND: Transradial artery (TRA) catheterization for neuroendovascular procedures is associated with a lower risk of complications than transfemoral artery (TFA) procedures. However, the majority of literature on TRA access pertains to diagnostic procedures rather than interventional treatments. OBJECTIVE: To compare TRA and TFA approaches for cerebrovascular interventions. METHODS: All patients with an endovascular intervention performed at a single center from October 1, 2018 to December 31, 2019 were retrospectively analyzed. Patients were grouped into 2 cohorts on the basis of whether TRA or TFA access was used. Outcomes included complications, fluoroscopy times, and total contrast administered. RESULTS: A total 579 interventional treatments were performed during the 15-mo study period. TFA procedures (n = 417) were associated with a significantly higher complication rate than TRA (n = 162) procedures (43 cases [10%] vs 5 cases [3%]; P = .008). After excluding patients who underwent thrombectomy and performing a propensity adjustment (including age, sex, pathology, procedure, sheath size, and catheter size), TRA catheterization was associated with decreased odds of a complication (odds ratio, 0.25; 95% CI 0.085-0.72; P = .01), but no significant difference in the amount of contrast administered (6.7-mL increase; 95% CI, -7.2 to 20.6; P = .34) or duration of fluoroscopy (2.1-min increase; 95% CI, -2.5 to 6.7; P = .37) compared with TFA catheterization. CONCLUSION: Neurointerventional procedures and treatments for a variety of pathologies can be performed successfully using the TRA approach, which is associated with a lower risk of complications and no difference in fluoroscopy duration compared with the TFA approach.

Endovascular Treatment of Aneurysms Using Flow-Diversion Embolization: 2-Dimensional Operative Video.

Initially developed for large and giant wide-necked aneurysms of the internal carotid artery, flow diverter devices are now used in almost every location safely and with effectiveness.1-5 This video demonstrates a unique case of a giant aneurysm of the right petrous internal carotid artery in a 20-yr-old patient. This is an extremely rare location, and most of patients are asymptomatic.3-6 Signs of compression of the seventh and eight cranial nerves can be present and even Horner syndrome and lower cranial nerves neuropathies. Nevertheless, rupture can lead to epistaxis and otorrhagia, and ultimately to hemorrhagic shock. The patient in the current report was otherwise healthy but presented with lightheadedness and dizziness for 10 d. The patient consented to the procedure. There was no history of major trauma or head and neck infection. A transradial endovascular flow diversion embolization of a giant aneurysm of the petrous internal carotid artery is herein demonstrated in a stepwise manner. A triaxial system was used to deploy 3 overlapping devices. Concepts of J-wire technique, multiple coverage,1 and the so-called weld technique are emphasized. The role of adjunctive coiling and main reasons for failure are also discussed.7,8 Brief cases of flow diversion embolization of aneurysms of different morphologies at different locations are used to highlight the importance of assessing vessel wall apposition and follow-up imaging.

Middle meningeal artery embolization for chronic subdural hematoma: an institutional technical analysis.

BACKGROUND: Recently, middle meningeal artery (MMA) embolization has emerged as a potentially safe and effective method of treating chronic subdural hematoma (cSDH). OBJECTIVE: To report a single-center experience with MMA embolization and examines the type of embolic material used, the extent of penetration, and the number of MMA branches embolized. METHODS: A retrospective analysis of all patients with MMA embolization from 2018 through 2019 was performed. A failed outcome was defined as either surgical rescue and/or greater than 10 mm of hematoma residual or reaccumulation following embolization. RESULTS: Of 35 patients, surgery had failed for 9 (26%) and initial conservative treatment had failed for 6 (17%). Of 41 MMA embolizations, including those in six patients with bilateral cSDH who underwent bilateral MMA embolization, 29 (72%) were performed using ethylene vinyl alcohol copolymer (Onyx), 7 (17%) using particles, and 5 (12%) using n-butyl cyanoacrylate. Both the anterior and posterior MMA divisions were embolized in 29 cases (71%); distal penetration of these branches was achieved in 25 embolizations (61%). Twenty-six (63%) cSDHs completely resolved. Complete resolution was seen in 22 of 29 hematomas (76%) in which both anterior and posterior MMA branches were occluded versus 4 of 12 (33%) following single-branch embolization (p=0.014). Embolization of one cSDH (2%) failed. CONCLUSION: MMA embolization of cSDHs appears to be both safe and efficacious. Furthermore, embolization of both the anterior and posterior MMA branches may be associated with increased odds of complete resolution.

Comparison of aspiration-first versus stentriever-first techniques in performing mechanical thrombectomy for large vessel occlusions.

BACKGROUND: Both stentriever and direct-aspiration thrombectomy effectively treat large-vessel occlusions. However, data are limited comparing clinical outcomes after aspiration-first versus stentriever-assisted aspiration for thrombectomy. METHODS: A retrospective cohort study compared procedure times and radiographic outcomes after two mechanical thrombectomy techniques (aspiration first or stentriever). To minimize bias and variability inherent to multi-operator series, we assessed consecutive patients with cerebrovascular occlusions treated by a single surgeon during a 1 year period at two stroke centers. Expanded Thrombolysis in Cerebral Infarction (eTICI) grades were assessed by an investigator blinded to treatment. RESULTS: Data from 93 patients (median age 70 years) were analyzed: 73 patients (78.5%) were treated with a strentriever-first strategy and 20 (21.5%) were treated with aspiration first, with stentriever rescue therapy required in only three of these cases following unsuccessful aspiration. There were no significant differences in patient demographics, sites of occlusion, or rates of tandem occlusions between aspiration-first and stentriever-assisted groups (p≥0.36). The rate of first-pass eTICI ≥2b was 75.0% (15/20) for aspiration-first and 52.1% (38/73) for strentriever-first groups (p=0.07), while the rate of final eTICI ≥2b was 100% (20/20) and 82.2% (60/72), respectively (p=0.04). The aspiration-first technique was associated with procedural times ≤25 min in a multivariable analysis (adjusted OR 4.77, 95% CI 1.15 to 18.39; p=0.03). CONCLUSIONS: In this single-surgeon series, an aspiration-first technique was associated with a statistically significant improvement in eTICI outcomes and faster procedure times compared with stentriever-assisted aspiration. Further prospective studies are necessary to minimize selection bias inherent in this study design.

Stent-Assisted Coiling of a Sidewall Aneurysm of the Distal Middle Cerebral Artery: 2-Dimensional Operative Video.

Sidewall aneurysm treatment often requires complex management strategies. These can include advanced clipping techniques or stent-assisted coiling techniques. Endovascular coiling alone has been associated with high recurrence rates and is often not feasible.1-4 Flow-diversion embolization has recently become a standard of care for many aneurysms, demonstrating high occlusion rates.4,5 However, the third generation of coil-assist stents can be delivered with 0.0165" microcatheters, being an ideal adjunct to manage this group of aneurysms in more distal locations. In this video, a 16-yr-old teenager with Parry-Romberg syndrome and congenital adrenal hyperplasia had an incidental finding of a 6.5-mm sidewall aneurysm arising off the angular branch of the left middle cerebral artery, found during the work-up of complex partial seizures. The patient consented to the procedure. Due to his young age and aneurysm size, a decision was made to treat the aneurysm through an endovascular approach. Under general anesthesia, a transfemoral approach was carried out using a 6-French short sheath. A 6-French guiding catheter was left in the distal cervical left internal carotid artery; a 0.0165" microcatheter was used to first deploy a 3.0 × 15 mm Neuroform Atlas stent, completely covering the length of the aneurysm. Then, the stent was traversed with the microcatheter to coil the aneurysm. Follow-up cerebral angiogram confirmed complete occlusion of the aneurysm.

Using the Lateral Pontine Safe Entry Zone for Resection of Deep-Seated Cavernous Malformations in the Lateral Pons: 2-Dimensional Operative Video.

The retrosigmoid approach is one of the main approaches used in the surgical management of pontine cavernous malformations. It definitely provides a lateral route to large central lesions but also makes possible resection of some ventral lesions as an alternative to the petrosal approaches. However, when these vascular malformations do not emerge on surface, one of the safe corridors delimited by the origin of the trigeminal nerve and the seventh-eight cranial nerve complex can be used.1-5 Baghai et al2 described the lateral pontine safe entry zone in 1982, as an alternative to approaches through the floor of the fourth ventricle when performing tumor biopsies. They advocated a small neurotomy performed right between the emergence of the trigeminal nerve and the facial-vestibulocochlear cranial nerves complex. Accurate image guidance, intraoperative cranial nerve monitoring, and comprehensive anatomical knowledge are critical for this approach.4,5 Knowing the natural history of a brainstem cavernous malformation after bleeding,6 we sought to demonstrate in this video: (1) the use of the retrosigmoid craniotomy in lateral decubitus for resection of deep-seated pontine cavernous malformations; (2) the wide opening of arachnoid membranes and dissection of the superior petrosal vein complex to improve surgical freedom and prevent use of fixed cerebellar retraction; and (3) the opening of the petrosal fissure and exposure of the lateral pontine zone for gross total resection of a cavernous malformation in a 19-yr-old female with a classical crossed brainstem syndrome. She had full neurological recovery after 3 mo of follow-up. The patient consented in full to the surgical procedure and publication of the video and manuscript.

Outcomes in a Case Series of Elderly Patients with Aneurysmal Subarachnoid Hemorrhages in the Barrow Ruptured Aneurysm Trial (BRAT).

BACKGROUND: Aneurysmal subarachnoid hemorrhage (aSAH) is debilitating in elderly patients, but literature regarding this population is scarce, and clinical decision-making remains debated. Outcomes of elderly patients with aSAH stratified by age and clinical presentation were analyzed. METHODS: Patients treated for aSAH were retrospectively analyzed. Patients were trichotomized into a young cohort (aged <60 years [n = 268]) and 2 elderly cohorts (aged 60-65 years [n = 60] and ≥65 years [n = 77]). The elderly cohorts were analyzed by poor or good scores at presentation (Hunt and Hess [HH] score >3 vs. ≤3, respectively) and poor functional outcome (modified Rankin Scale score >2). RESULTS: Of 137 elderly patients, 121 had a 6-year follow-up. The >65-year-olds (75% [52/69]) were more likely to have poor functional outcomes than the 60 to 65-year-olds (48% [25/52]) (odds ratio, 3.3; 95% confidence interval, 1.5-7.1; P = 0.002). Among those with an HH score ≤3 at presentation (n = 90), the >65-year-old cohort had poorer outcomes than the 60 to 65-year-old cohort at 6-year follow-up (69% [35/51] vs. 36% [14/39], respectively; odds ratio, 3.9; 95% confidence interval, 1.6-9.4; P = 0.003). Among patients with an HH score >3, no statistically significant differences in functional outcome were observed between the >65-year-old (n = 18) and 60 to 65-year-old (n = 13) cohorts. CONCLUSIONS: Elderly patients with aSAH are at high risk for poor functional outcomes. However, among those presenting with good HH scores, younger-elderly patients (aged 60-65 years) tend to fare better than older-elderly patients (aged >65 years). Elderly patients presenting with high-grade aSAH fare poorly regardless of age, which can inform clinical decision-making and prognostication.

Postembolization Change in Magnetic Resonance Imaging Contrast Enhancement of Meningiomas Is a Better Predictor of Intraoperative Blood Loss Than Angiography.

BACKGROUND: Preoperative embolization of meningiomas to reduce tumor vascularity and intraoperative blood loss remains controversial. Incomplete devascularization on angiography is not significantly correlated with intraoperative estimated blood loss (EBL). Magnetic resonance imaging (MRI) may provide a better assessment of devascularization and prediction of EBL. METHODS: We retrospectively analyzed patients undergoing preoperative embolization for intracranial meningiomas. Cohorts based on postembolization devascularization (>50% vs. ≤50%) were compared. RESULTS: Of 84 patients with meningioma undergoing preoperative embolization, 35 (42%) had a postembolization MRI before resection and met study inclusion criteria. The mean tumor diameter was 4.9 ± 1.3 cm, and mean intraoperative EBL was 576 ± 341 mL. Compared with MRI, angiography overestimated devascularization in 22 patients (63%). Using pre- versus postembolization MRIs, 17 (49%) patients had a >50% decrease in enhancement, which was associated with lower mean intraoperative blood loss (444 ± 255 mL) compared with 17 patients with ≤50% devascularization (700 ± 374 mL) (P = 0.03). On angiography, the 22 (63%) patients who demonstrated >50% devascularization during embolization did not statistically differ in intraoperative EBL when compared with 13 (37%) patients with <50% angiographic devascularization. Patients with a ≤50% decrease in contrast enhancement on postembolization MRI were 9 times more likely to lose >500 mL blood intraoperatively during resection (95% confidence interval 1.6-54, P = 0.01). CONCLUSIONS: Postembolization contrast-enhanced MRI is a better predictor of intraoperative blood loss during meningioma resection than postembolization angiography, which overestimates the degree of embolic devascularization. Postembolization preoperative MRI is warranted for optimal patient management.

Selective posterior cerebral artery amobarbital test: a predictor of memory following subtemporal selective amygdalohippocampectomy.

BACKGROUND: The selective posterior cerebral artery (PCA) amobarbital test, or PCA Wada test, is used to predict memory impairment after epilepsy surgery in patients who have previously had a failed internal carotid artery (ICA) amobarbital test. METHODS: Medical records from 2012 to 2018 were retrospectively reviewed for all patients with seizures who underwent a selective PCA Wada test at our institution following a failed or inconclusive ICA Wada test. Standardized neuropsychological testing was performed before and during the Wada procedure and postoperatively in patients who underwent resection. RESULTS: Thirty-three patients underwent a selective PCA Wada test, with no complications. Twenty-six patients with medically refractory epilepsy had a seizure focus amenable to selective amygdalohippocampectomy (AHE). Six patients (23%, n=26) had a failed PCA Wada test and did not undergo selective AHE, seven (27%) declined surgical resection, leaving 13 patients who underwent subtemporal selective AHE. Hippocampal sclerosis was found in all 13 patients (100%). Twelve patients (92%) subsequently underwent formal neuropsychological testing and all were found to have stable memory. Ten patients (77%) were seizure-free (Engel Class I), with average follow-up of 13 months. CONCLUSION: The selective PCA Wada test is predictive of memory outcomes after subtemporal selective AHE in patients with a failed or inconclusive ICA Wada test. Furthermore, given the low risk of complications and potential benefit of seizure freedom, a selective PCA Wada test may be warranted in patients with medically intractable epilepsy who are candidates for a selective AHE and who have a prior failed or inconclusive ICA Wada test.

Complications of femoral versus radial access in neuroendovascular procedures with propensity adjustment.

BACKGROUND: The transradial artery (TRA) approach for neuroendovascular procedures continues to gain popularity, but neurointerventionalists still lag behind interventional cardiologists in the adoption of a TRA-first approach. This study compares the complications and efficiency of the TRA approach to the standard transfemoral artery (TFA) approach at our institution during our initial phase of adopting a TRA-first approach. METHODS: A retrospective analysis was performed on all consecutive neuroangiographic procedures performed at a large cerebrovascular center from October 1, 2018 to June 30, 2019. The standard TFA approach was compared with TRA access, with the primary outcome of complications analyzed via a propensity-adjusted analysis. RESULTS: A total of 1050 consecutive procedures were performed on 877 patients during this 9-month period; 206 (20%) procedures were performed via TRA and 844 (80%) via TFA. The overall complication rate was significantly higher with the TFA procedures than with the TRA procedures (7% (60/844) vs 2% (4/206), respectively; p=0.003). A propensity-adjusted analysis showed that the TFA approach was a significant risk factor for a complication (OR 3.6, 95% CI 1.3 to 10.2, p=0.01). However, the propensity analysis showed that fluoroscopy times were on average 4 min less for TFA procedures than for TRA procedures (p=0.003). CONCLUSION: The TRA approach for neuroendovascular procedures appears to be safer than the TFA approach. Although a steep learning curve is initially encountered when adopting the TRA approach, the transition to a TRA-first practice can be performed safely for neurointerventional procedures and may reduce complications.

Flow diverters as a scaffold for treating direct carotid cavernous fistulas.

BACKGROUND: Direct carotid-cavernous sinus fistulas (dCCFs) are high flow arteriovenous shunts between the internal carotid artery and the cavernous sinus. Recently, we have used the pipeline embolization device (PED) to treat dCCFs. METHODS: We describe our experience treating patients with dCCFs in whom the PED was placed as the primary treatment modality. RESULTS: Five patients with dCCFs were treated with PEDs deployed in the ipsilateral internal carotid artery spanning the fistula. All patients also underwent either adjunctive transvenous or transarterial embolization. The PED served both as the primary treatment modality and as a scaffold that facilitated safe and efficacious transvenous embolysate administration by altering the flow dynamics through the fistula and providing a physical barrier that protected the internal carotid artery. No intraoperative or perioperative complications occurred. One of the five patients exhibited complete angiographic resolution of the fistula immediately after the procedure. The remaining four patients experienced complete obliteration of the fistula without additional treatment, which suggests that the PED induced alteration promoted thrombosis of the fistula. Therefore, 100% of patients in this series exhibited complete and durable obliteration of the fistula and complete resolution of symptoms following treatment. CONCLUSIONS: We believe that use of the PED to treat dCCFs may be a safe and efficacious strategy that facilitates parent vessel protection during transvenous embolization. Furthermore, the flow alterations induced by the PED may promote thrombosis of incompletely occluded fistulas. This is the largest reported series of non-iatrogenic dCCFs treated with use of the PED as the primary initial treatment strategy.

The pretemporal approach to anterolateral midbrain cavernous malformations.

Operating on the anterolateral midbrain is challenging due to limited surgical freedom provided by classic approaches and restraints imposed by the basilar artery apex and branches, their perforators, and the oculomotor nerve (Abla et al., 2011; Bricolo and Turazzi, 1995; Cavalcanti et al., 2016). This video demonstrates the benefits provided by the pretemporal approach for resection of an anterolateral mesencephalic cavernous malformation (Chaddad-Neto et al., 2014; de Oliveira et al., 1995). Four steps are well demonstrated in the video: 1) section of temporal pole veins to the sphenoparietal sinus; 2) division of arachnoid attaching the oculomotor nerve to the tentorial edge and uncus; 3) releasing the arachnoid between the anterior choroidal artery and uncus; and 4) following the oculomotor nerve to its origin. The video can be found here: https://youtu.be/7ZuK-ewNo6w.

Median suboccipital craniotomy and telovelar approach for posterior pontine cavernous malformations.

The pons is the preferred location for cavernous malformations in the brainstem. When these lesions do not surface, it is critical to select the optimal safe entry zone to reduce morbidity.1-3 In this video, we demonstrate in a stepwise manner the medial suboccipital craniotomy and the telovelar approach performed in a lateral decubitus position. They were used to successfully resect a pontine cavernous malformation in a centroposterior location in a 19-year-old patient with diplopia, right-sided numbness, and imbalance. The paramedian supracollicular safe entry zone was used once the lesion did not reach the ependymal surface.2,3 Late magnetic resonance imaging demonstrated total resection and the patient was neurologically intact after 3 months of follow-up. The approach is also demonstrated in a cadaveric dissection to better illustrate all steps. The video can be found here: https://youtu.be/ChArkxA8kig.

Anatomical and Objective Evaluation of the Main Surgical Approaches to Pontine Intra-Axial Lesions.

OBJECTIVE: Apparently similar intra-axial pontine lesions may demand distinct surgical approaches. Selecting the optimal approach reduces unnecessary manipulation of tracts and nuclei. This study aims to reveal a quantitative analysis of main surgical corridors dealing with intrinsic pontine pathology. METHODS: Six approaches were performed repeatedly in 10 cadaveric heads: 1) retrosigmoid, 2) retrolabyrinthine, 3) subtemporal transtentorial, 4) anterior petrosectomy, 5) combined petrosal approach, and 6) suboccipital telovelar. Six safe entry zones were studied: peritrigeminal, supratrigeminal, lateral pontine, supracollicular, infracollicular, and median sulcus of fourth ventricle. A neuronavigation device was used to collect 3-dimensional coordinates from fixed points over the edge of craniotomies and brainstem surface; 4 variables were studied: 1) angles of attack; 2) areas of exposure; 3) lengths of exposure; and 4) trajectories. RESULTS: The mean area of exposure generated by the retrosigmoid approach over the brainstem was 538.6 ± 161.0 mm2, whereas that yielded by the retrolabyrinthine was 475.0 ± 173.4 mm2. There were no significant differences between both when considering areas of exposure and angles. Adding a tentorial cut to the subtemporal approach exposed the superior part of the lateral surface of pons; the area of exposure increased a mean of 33% (P < 0.001). CONCLUSIONS: In addition to producing similar areas and angles of attack, the retrolabyrinthine yields a more orthogonal trajectory to lateral pons than the retrosigmoid approach. Adding a tentorial cut and anterior petrosectomy significantly increased areas and lengths of exposure of a regular subtemporal approach. The combined approach significantly increased angles of attack to both the supratrigeminal and lateral pontine safe zones.

Accessing the Anterior Mesencephalic Zone: Orbitozygomatic Versus Subtemporal Approach.

BACKGROUND: Despite the latest developments in microsurgery, electrophysiological monitoring, and neuroimaging, the surgical management of intrinsic brainstem lesions remains challenging. Several safe entry points have been described to access the different surfaces of the brainstem. Knowledge of this entry zone anatomy is critical to performing a safe and less morbid approach. To access the anterior midbrain surface, a well-known entry point is the anterior mesencephalic (AM) zone. Our aim was to quantify surgical AM zone exposure through the orbitozygomatic (OZ) and subtemporal (ST) approaches. We also analyzed the angular exposure along the horizontal and vertical axis angles for the AM zone. METHODS: Ten cadaveric heads were dissected using the OZ and ST approaches for anterior midbrain surface exposure. A neuronavigation system was used to determine the 3-dimensional coordinates. The area of surgical exposure, angular exposure, and anatomical limits of each craniotomy were evaluated and determined using software analysis and compared for intersection areas and AM safe zone exposure. RESULTS: The median surgical exposure was 164.7 ± 43.6 mm2 for OZ and 369.8 ± 70.1 mm2 for ST (P = 0.001). The vertical angular exposure was 37.7° ± 9.92° for the OZ and 18.4° ± 2.8° for the ST opening (P < 0.001). The horizontal angular exposure to the AM zone was 37.9° ± 7.3° for the OZ and 47.0° ± 3.2° for the ST opening (P = 0.002). CONCLUSIONS: Although the OZ craniotomy offers reduced surgical exposure, it provides a better trajectory to the AM zone compared with the ST approach.