Lateral Anterior Column Release in Short Lumbar Fusion Is It Worth It?

BACKGROUND: Radiographic adjacent segment disease (ASD) ranges from 10% to 84%, depending on technique. Occurrence of symptomatic ASD is lower, with a range of 1.9% to 13%. ASD can be very debilitating and necessitate further procedures, leading to high morbidity. Herein, we explore the occurrence of adjacent segment disease when performing anterior column release in lateral interbody fusion. METHODS: After institutional review board approval, 120 total patients who underwent lateral lumbar interbody fusion (LLIF) at our facility from 2013 to 2020 were retrospectively reviewed, allowing for a minimum of 3 years for follow-up time. Surgical variables and spinopelvic parameters were measured and collected by our team. Statistical measures of significance were calculated using IBM SPSS Statistics Version 29. RESULTS: One hundred twenty total patients were included. 73.3% of patients had percutaneous screws, and 11.7% had open. Thirteen patients underwent LLIF with anterior column release (ACR). The mean lumbar lordosis (LL) was 50.1 ± 12.9, pelvic incidence (PI) was 52.8 ± 11.2, sacral slope was 33.6 ± 9.2, pelvic tilt was 18.1 ± 6.8, and sagittal vertical axis was 6.8 mm ± 30.5.Twenty four total patients had ASD after LLIF. In univariable analysis, ACR (P < 0.001) and PI-LL Mismatch (P < 0.035) were risk factors for developing ASD. In multivariable analysis, greater PI-LL mismatch was predictive of ASD (P < 0.005, OR = 1.097, and 95% confidence interval = 1.029-1.171), as was ACR (P < 0.001, OR = 9.667, and 95% confidence interval = 2.669-35.09). CONCLUSIONS: Higher PI-LL mismatch after lumbar interbody fusion, and performance of an ACR during LLIF increased the likelihood of developing symptomatic ASD in our patients. Considering ACR to achieve the goal of correcting spinopelvic parameters should be carefully evaluated when undertaking a lateral approach.

Application of Topographical Anatomy of the Trochlear Nerve in Transtentorial Approaches: An Anatomic Study.

BACKGROUND AND OBJECTIVES: Transection of the free edge of tentorium (FET) might be necessary when approaching cavernous sinus lesions, clip placement in certain posterior communicating artery aneurysms, or during transpetrosal and retrosigmoid transtentorial approaches. No anatomic study has investigated the relationship of the trochlear and oculomotor nerve and FET in an attempt to identify a safe zone for such maneuver. METHODS: Ten embalmed specimens (20 sides) were studied and the following morphometric measurements were taken using digital microcalipers: trochlear (TP) to oculomotor porus (OP), length of the intratentorial segment of cranial nerve (CN) IV, nerve free FET, and distance along the oculomotor (CN III) from its OP to CN III/trochlear (CN IV) crossing and angle between the long-axis petrous ridge and TP (petrotrochlear angle). RESULTS: The CN IV pierced the deep layer of the FET in all cases at a mean distance 8.11 mm (4.43-11.33) posterior to the OP, measured along the FET. CN IV continued within the tentorial edge for a mean of 6.17 mm (3.18-11.33) before entering the cavernous sinus at a mean distance of 1.9 mm (0-5.46 mm) from the posterior-most aspect of the OP. A nerve-free portion of FET was 1.93 mm (mean) (0-5.46). No nerve-free FET segment (<1 mm) was observed in 4 sides (20%), and a nerve-free FET segment <2.00 mm was seen in 55% of cases. The mean distance from OP to the CN III/IV crossing was 10.17 mm (1.00-15.57). The mean petrotrochlear angle was 164.49° (140.01-183.85), and >175° in 4 specimens (20%). CONCLUSION: Our data confirm presence of the intratentorial segment of CN IV. Transection of the FET carries the lowest risk of CN IV injury if performed < 2 mm or >10 mm posterior to the OP, or posterior to intersection of the FET and a virtual extension of a petrous ridge.

Timing of Embolization, Radiosurgery, and Resection of Arteriovenous Malformations in Pediatric Patients: A Retrospective, Descriptive Study.

OBJECTIVE: Cerebral arteriovenous malformations (AVMs) are a challenging pathology in pediatric patients, carrying a high risk of morbidity and mortality. Treatment modalities include resection, endovascular embolization, and stereotactic radiosurgery. There is currently no consensus favoring one modality over another. Timing of multimodal therapy with embolization/stereotactic radiosurgery and resection is not well explored in the literature. We present a series of pediatric patients with AVMs, with special attention directed to the timing of treatment. METHODS: Electronic medical records of all pediatric patients (<18 years old at treatment) with AVMs treated at our institution were retrospectively reviewed after institutional review board approval. Demographic information, AVM characteristics, treatment variables, and outcomes were recorded. RESULTS: In our cohort of 27 patients, 21 (77.8%) presented with a ruptured AVM. Of these patients, 6 (28.6%) had a Glasgow Coma Scale score of 3-10 and underwent treatment within 24 hours of presentation, and 10 (47.6%) with a Glasgow Coma Scale score of 12-15 were treated between 24 and 120 hours after presentation. The remaining 5 patients (23.8%) were treated 3 weeks to 14 months after AVM rupture. Regardless of rupture status, 96% of our cohort had a modified Rankin Scale score of 1-2 at most recent follow-up. CONCLUSIONS: We present our institution's experience with pediatric AVMs, focusing on the timing of treatment. Based on our experience, early treatment of AVMs seems to be safe and effective regardless of rupture status.

Temporal lobe injury with middle fossa approach to intracanalicular vestibular schwannomas: a systematic review.

There are several surgical approaches for vestibular schwannoma (VS) resection. However, management has gradually shifted from microsurgical resection, toward surveillance and radiosurgery. One of the arguments against microsurgery via the middle fossa approach (MFA) is the risk of temporal lobe retraction injury or sequelae. Here, we sought to evaluate the incidence of temporal lobe retraction injury or sequela from a MFA via a systematic review of the existing literature. This systematic review was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Relevant studies reporting temporal lobe injury or sequela during MFA for VS were identified. Data was aggregated and subsequently analyzed to evaluate the incidence of temporal lobe injury. 22 studies were included for statistical analysis, encompassing 1522 patients that underwent VS resection via MFA. The overall rate of temporal lobe sequelae from this approach was 0.7%. The rate of CSF leak was 5.9%. The rate of wound infection was 0.6%. Meningitis occurred in 1.6% of patients. With the MFA, 92% of patients had good facial outcomes, and 54.9% had hearing preservation. Our series and literature review support that temporal lobe retraction injury or sequelae is an infrequent complication from an MFA for intracanalicular VS resection.

A Nod for Meckel: A Novel Surgical Position Utilizing Meckel's Cave Anatomy for Percutaneous Glycerol Rhizotomy in Trigeminal Neuralgia.

Objective We aim to describe a novel positioning technique using a specific surgical table to achieve the optimal angle during percutaneous glycerol rhizotomy (PGR) for trigeminal neuralgia (TN). Design This is a descriptive and photographic analysis of successful cases for future implementation. Setting This study was conducted at a single-institution, academic center. Participants The participants were adult patients with TN who underwent PGR and provided consent for publication. Main Outcome Measures Primary outcomes of this study were TN symptomatic relief and surgical complications. Results The use of a beach chair sliding headboard surgical table for PGR is plausible and ensures precise and immobile head flexion for 1 hour postglycerol injection. There were no intraoperative or postoperative complications. All patients achieved successful reduction of TN symptoms. Conclusions Utilizing this new method of intraoperative navigation with a unique surgical table in the upright position, surgeons may achieve precise head adjustments post-PGR. Head flexion has been postulated as a means of ensuring glycerol containment in Meckel's cave. This method can help standardize this procedure for future systematic studies on the importance of head positioning post-PGR.

C1-C2 intraarticular distraction with anterior cervical cages for basilar invagination realignment: Operative technique nuances and review of literature.

Neurosurgical management of basilar invagination (BI) has traditionally been aimed at direct cervicomedullary decompression through transoral dens resection or suboccipital decompression with supplemental instrumented fixation. Dr. Goel introduced chronic atlantoaxial dislocation (AAD) as the etiology in most cases of BI and described a technique for distracting the C1-C2 joint with interfacet spacers to achieve reduction and anatomic realignment. We present our modification to Goel's surgical technique, in which we utilize anterior cervical discectomy (ACD) cages as C1-C2 interfacet implants. A young adult male presented to our institution with BI, cervicomedullary compression, occipitalization of C1, and Chiari 1 malformation. There was AAD of C1 over the C2 lateral masses. This reduced some with preoperative traction. He underwent successful C1-C2 interfacet joint reduction and arthrodesis with anterior cervical discectomy (ACD) cages and concomittant occiput to C2 instrumented fusion. BI can be effectively treated through reduction of AAD and by utilizing ACD cages as interfacet spacers.

Nasofrontal meningiomas: retrospective series and review of literature.

INTRODUCTION: Lesions affecting the anterior skull base and involving the paranasal sinuses (PNS), nasal cavity (NC), and orbit are infrequent and include predominantly a wide variety of sinonasal malignancies. Less than 3% of intracranial meningiomas extend extracranially and involve PNS and NC. Given their relatively low incidence, little is known about the treatment outcome of this subset of meningiomas. METHODS: Systematic literature and retrospective review of own institutional series of midline anterior skull base meningiomas with significant PNS and NC involvement were performed. RESULTS: Overall, 21 patients-16 in the literature review group and 5 of our institutional series-were included. Eleven (52.4%) patients had had a prior surgery for midline anterior skull base meningioma. Of patients having reported WHO grade, two were WHO II. Gross total resection was achieved in 16 (76.2%) of patients, utilizing solely transcranial approach in 15 patients, combined endoscopic and transcranial in five patients and purely endoscopic in one patient. Postoperative radiotherapy was administered in three (14.3%) patients, all after total resection via transcranial route, without a history of prior treatment. A postoperative cerebrospinal fluid leak was reported in four (10%) patients, requiring surgical repair in two. There were no reports of postoperative meningitis. No neurological complications were observed except of a reported worsening of vision in one patient. CONCLUSION: Midline anterior skull base meningiomas infrequently extend significantly into the PNS and NC. Despite their significant involvement, along with concomitant involvement of orbit, gross total resection is possible in the majority of cases with low morbidity using either purely transcranial or combined endoscopic/transcranial approach.

Percutaneous Vertebroplasty and Upper Instrumented Vertebra Cement Augmentation Reducing Early Proximal Junctional Kyphosis and Failure Rate in Adult Spinal Deformity: Case Series and Literature Review.

BACKGROUND AND OBJECTIVES: One of the risks involved after long-segment fusions includes proximal junctional kyphosis (PJK) and proximal junctional failure (PJF). There are reported modalities to help prevent this, including 2-level prophylactic vertebroplasty. In this study, our goal was to report the largest series of prophylactic cement augmentation with upper instrumented vertebra (UIV) + 1 vertebroplasty and a literature review. METHODS: We retrospectively reviewed our long-segment fusions for adult spinal deformity from 2018 to 2022. The primary outcome measures included the incidence of PJK and PJF. Secondary outcomes included preoperative and postoperative Oswestry Disability Index, visual analog scale back and leg scores, surgical site infection, and plastic surgery closure assistance. In addition, we performed a literature review searching PubMed with a combination of the following words: "cement augmentation," "UIV + 1 vertebroplasty," "adjacent segment disease," and "prophylactic vertebroplasty." We found a total of 8 articles including 4 retrospective reviews, 2 prospective reviews, and 2 systematic reviews. The largest cohort of these articles included 39 patients with a PJK/PJF incidence of 28%/5%. RESULTS: Overall, we found 72 long-segment thoracolumbar fusion cases with prophylactic UIV cement augmentation with UIV + 1 vertebroplasty. The mean follow-up time was 17.25 months. Of these cases, 8 (11.1%) developed radiographic PJK and 3 (4.2%) required reoperation for PJF. Of the remaining 5 patients with radiographic PJK, 3 were clinically asymptomatic and treated conservatively and 2 had distal fractured rods that required only rod replacement. CONCLUSION: In this study, we report the largest series of patients with prophylactic percutaneous vertebroplasty and UIV cement augmentation with a low PJK and PJF incidence of 11.1% and 4.2%, respectively, compared with previously reported literature. Surgeons who regularly perform long-segment fusions for adult spinal deformity can consider this in their armamentarium when using methods to prevent adjacent segment disease because it is an effective modality in reducing early PJK and PJF that can often result in revision surgery.

Risk Factors for Adjacent Segment Disease in Short Segment Lumbar Interbody Fusion-A Case Series.

BACKGROUND: Adjacent segment disease (ASD) is a common problem after lumbar spinal fusions. Ways to reduce the rates of ASD are highly sought after to reduce the need for reoperation. OBJECTIVE: To find predisposing factors of ASD after lumbar interbody fusions, especially in mismatch of pelvic incidence and lumbar lordosis (PI-LL). METHODS: We conducted a retrospective cohort study of all patients undergoing lumbar interbody fusions of less than 4 levels from June 2015 to July 2020 with at least 1 year of follow-up and in those who had obtained postoperative standing X-rays. RESULTS: We found 243 patients who fit inclusion and exclusion criteria. Fourteen patients (5.8%) developed ASD, at a median of 24 months. Postoperative lumbar lordosis was significantly higher in the non-ASD cohort (median 46.4° ± 1.4° vs 36.9° ± 3.6°, P < .001), pelvic tilt was significantly lower in the non-ASD cohort (16.0° ± 0.66° vs 20.3° ± 2.4°, P = .002), PI-LL mismatch was significantly lower in the non-ASD cohort (5.28° ± 1.0° vs 17.1° ± 2.0°, P < .001), and age-appropriate PI-LL mismatch was less common in the non-ASD cohort (34 patients [14.8%] vs 13 [92.9%] of patients with high mismatch, P < .001). Using multivariate analysis, greater PI-LL mismatch was predictive of ASD (95% odds ratio CI = 1.393-2.458, P < .001) and age-appropriate PI-LL mismatch was predictive of ASD (95% odds ratio CI = 10.8-970.4, P < .001). CONCLUSION: Higher PI-LL mismatch, both age-independent and when adjusted for age, after lumbar interbody fusion was predictive for developing ASD. In lumbar degenerative disease, correction of spinopelvic parameters should be a main goal of surgical correction.

Transcarotid artery revascularization (TCAR) stenting or angioplasty for intracranial carotid artery stenosis: Case series and novel application.

BACKGROUND: Carotid artery stenting is associated with a higher rate of stroke compared to carotid endarterectomy (CEA). This is likely due to procedural emboli resulting from plaque disruption. The transcarotid artery revascularization (TCAR) method aims to reduce the stroke rate by flow-reversal. TCAR, which has yet to be utilized for intracranial atherosclerotic disease (ICAD), may be particularly valuable given the lack of surgical treatment options for intracranial arterial stenosis. OBJECTIVE: Presented here are five cases of angioplasty or stenting that demonstrate the feasibility of TCAR for intracranial Internal Carotid Artery (ICA) stenosis treatment. METHODS: Five cases were reviewed retrospectively and summarized using PROCESS and CARE guidelines. RESULTS: All patients who underwent intervention between the petrous and ophthalmic segment of the ICA had no new neurologic deficit nor detected embolic stroke. One patient experienced an asymptomatic 5 mm hemorrhage on postoperative routine Computed Tomography (CT) head imaging. CONCLUSIONS: This highlights a new method for treating intracranial ICA stenosis with a potentially reduced stroke risk. Given the historically higher stroke rates for cervical ICA stenting compared to carotid artery endarterectomy, this method may improve the previously higher stroke rates in endovascular carotid artery treatment, compared to CEA. Although this series is small, it illustrates a novel use for a rising technique that should be further evaluated in a larger study to validate its efficacy as a new treatment modality for surgically inaccessible intracranial disease.

Kyphoplasty of C2 Pathological Fractures Using an Anterior Midline Approach and Steerable Osteotome: Technical Note and Case Series.

BACKGROUND: Malignant lesions involving the C2 vertebral body (axis) may be challenging to treat, and not all patients with cancer are good candidates for posterior cervical or occipitocervical instrumentation. OBJECTIVE: To describe a modified technique of the direct anterolateral C2 kyphoplasty using a steerable osteotome, commonly used for the treatment of thoracolumbar spinal lesions. We also report a case series of 11 patients treated with this technique at our institution. METHODS: The authors performed a retrospective review of all patients who underwent a C2 kyphoplasty using the anterior midline approach from 2010 to 2020. Patient demographics, tumor characteristics, pain severity (visual analog scale), Karnofsky performance status , perioperative complications, and postoperative spinal stability were assessed. RESULTS: The main indication for a C2 kyphoplasty was refractory neck pain. All patients tolerated the procedure well. There were no intraoperative complications. One patient developed transient dysphagia. Visual analog scale scores were 9.00 ± 1.10 preoperative and 3.73 ± 1.85 at 2 weeks and 1.67 ± 1.66 at 3 months after the procedure and continued to stay low during the remainder of the follow-up (4-60 months). The Karnofsky performance status improved from 72.73 ± 11.04 preoperatively to 82.22 ± 8.33 at 2 weeks and 86.67 ± 5.00 at 3 months after the procedure. There was no evidence of new occurrence or progression of C2 fractures. CONCLUSION: The anterior kyphoplasty using a steerable osteotome for tumors of the axis can result in lasting pain reduction and improved cervical stability while demonstrating a low complication rate.

Neuromuscular Scoliosis: A Dual-Surgeon Approach.

OBJECTIVE: Neuromuscular Scoliosis (NMS) causes severe deformity and operative correction for these patients carries high complication rates. We present a retrospective study comparing a series of consecutive patients who underwent posterior fusion via a single-surgeon (SS) approach with a consecutive series of patients treated via a dual-surgeon (DS) approach. METHODS: Patients with NMS who underwent posterior fusion via a SS approach from 2019 to 2022 were analyzed and compared to a series of patients with NMS who underwent posterior fusion via a DS approach. RESULTS: In the SS group, the average estimated blood loss (EBL) was 675 mL, average length of stay (LOS) was 6.3 days, average operative time (OT) was 6.5 hours, average packed red blood cell transfusion was 1.5 units, with a complication rate of 30%. The DS group had an average EBL of 400 mL, a LOS of 4.8 days, an OT of 4.75 hours, an average packed red blood cell transfusion of 0.8 units, with a complication rate of 20%. The DS approach was significant for a lower EBL, OT (P < 0.001), and LOS (P < 0.03). CONCLUSIONS: This study suggests that for patients with NMS the DS approach decreases OT, EBL, complication rates, and LOS. This further supports that this approach may benefit outcomes in NMS patients.

Postoperative magnetic resonance imaging signal changes in middle cerebral peduncle after vestibular schwannoma surgery.

BACKGROUND AND PURPOSE: Preoperative compression of middle cerebellar peduncle (MCP) is often observed in vestibular schwannomas. Its re-expansion is expected after tumour resection, however, frequently its thickness remains unchanged or undergoes further atrophy. Similarly, increased MCP FLAIR signal is often observed and thought to be associated with intraoperative MCP injury. This study investigates the dynamics of MCP FLAIR signal changes over time and their implications in long-term MCP atrophy. MATERIALS AND METHODS: Retrospective analysis of patients operated between 2011 and 2019 was performed. Measurements of FLAIR signals and MCP thickness were performed preoperatively, postoperatively and at follow-up. RESULTS: 28 patients (15 females, mean age 51.94 years) were included. The mean follow-up was 23.98 months. The mean tumour size was 2.99 cm. The MCP FLAIR signal was elevated preoperatively in 10 (35.7%) patients and further increased postoperatively in 22 (78.6%), followed by its decrease at follow up (7 patients, 25%). An immediate postoperative re-expansion of middle cerebellar peduncle was observed in 24 (85.7%) patients. No association between tumour size and preoperative FLAIR was established, however tumour size was negatively associated with the MCP thickness. A significant negative association between a postoperative FLAIR and follow-up thickness (p < 0.001) was noted, even if controlling for tumour size and both tumour size and preoperative MCP thickness. CONCLUSION: In patients with vestibular schwannomas undergoing surgical resection, the middle cerebellar peduncle FLAIR signal seems to associated with long term thickness of MCP, regardless of its initial size, however does not seem to correlate with the clinical outcome.

Molecular determinants of outcomes in meningiomas.

Meningiomas are the most common intracranial primary tumor in adults. Surgery is the predominant therapeutic modality for symptomatic meningiomas. Although the majority of meningiomas are benign, there exists a subset of meningiomas that are clinically aggressive. Recent advances in genetics and epigenetics have uncovered molecular alterations that drive tumor meningioma biology with prognostic and therapeutic implications. In this review, we will discuss the advances on molecular determinants of therapeutic response in meningiomas to date and discuss findings of targeted therapies in meningiomas.

Paramedian Wiltse Approach for Giant Paraspinal Lumbar Schwannoma: Technical Note and Alternative Approaches.

BACKGROUND: Paraspinal lumbar schwannomas are primarily located outside of the spinal canal with minimal extension into the neural foramen. Approaching these tumors through a traditional posterior approach can be challenging given their lateral location to the spine and is likely to require extensive bony removal and potential destabilization of the spine. Alternatives approaches have been identified that may circumvent the need for extensive bony removal. OBJECTIVE: To examine the use of the paramedian Wiltse approach for giant extraspinal tumors and compare the approach with other nonposterior approaches. METHODS: We present 2 cases in which the paramedian Wiltse approach is used to effectively approach large paraspinal schwannomas and achieve complete tumor resection without destabilization of the spine. RESULTS: The paramedian Wiltse approach along with expandable retractors systems were able to achieve complete resection of the giant paraspinal schwannomas. Neural preservation was able to be achieved in one case which was facilitated by the exposure achieved through the posterior paramedian corridor that allowed for visualization of the proximal and distal ends of the tumor. CONCLUSION: The paramedian Wiltse approach is an ideal approach to target large extraspinal schwannomas for complete resection and potential neural preservation without the need for destabilization of the spine.

Resection of Giant Remote Recurrence of Ependymoma After 41 Years.

Ependymomas are rare primary tumors of the brain and spinal cord that arises from the ependymal cell layer. Cranial ependymomas commonly occur in the posterior fossa; however, approximately 30% of all tumors can be found in the supratentorial region. Supratentorial ependymomas have a shorter progression-free and overall survival than their infratentorial counterparts. We present the case of a 47-year-old man who presented with mild left-sided hemiparesis and confusion secondary to a right-sided 8.5 × 6.0 × 6.0 cm frontotemporal neoplasm encasing the ipsilateral internal and middle cerebral arteries. The patient had undergone a suboccipital craniectomy for resection of a posterior fossa ependymoma at 6 years of age (41 years ago). After multidisciplinary discussion, we performed a right frontotemporal craniotomy for tumor resection (Video) using intraoperative navigation, ultrasound, and intraoperative neurophysiological monitoring. While skeletonizing branches of the middle cerebral artery, an M3 branch was injured inadvertently and repaired immediately. Histopathologic specimens were consistent with ependymoma (World Health Organization grade II). A near-total resection was achieved. The patient developed a transient left-sided hemiparesis but improved to full strength on discharge from the hospital.

The Final Cut: Evolution of Cavernous Sinus Decompression Beyond the Dolenc Cut.

BACKGROUND: Meningiomas involving the cavernous sinus (CS) represent a formidable challenge to neurosurgeons. Because of high morbidity, aggressive tumor resection within the CS has been largely replaced by extracavernous tumor resection and decompression of the CS. The widely used Dolenc method involves blind dural transection over the oculomotor nerve, potentially placing the crossing trochlear nerve at risk. OBJECTIVE: To provide a safer way for the decompression of the CS and at the same time, circumferential resection of the temporal lobe dura. METHODS: Cadaveric dissection of 8 cadaveric heads (16 sides) was performed. Frontotemporal craniotomy with zygomatic osteotomy was performed. Extradural and intradural dissection of the lateral wall of the CS and free edge of tentorium was performed. Photographic documentation, artistic illustrations, and illustrative video cases are provided. RESULTS: Three tether points were released: anterior-the meningo-orbital band, lateral-dura over the V2 and V3, and medial-superficial layer of the free edge of tentorium. Transection of the superficial layer of the free edge of the tentorium along its edge, in conjunction with a lateral cut over the temporal convexity, constitutes the final cut, allowing a resection of the lateral CS wall and the circumferential resection of temporal lobe dura. CONCLUSION: Using the "final cut" technique allows for a circumferential resection of the temporal lobe dura and lateral CS wall while avoiding blind cuts that could put cranial nerves at risk. All dural transections are performed in anatomically separated layers under constant visualization.

Factors associated with in-stent stenosis after cerebral aneurysm embolization using a Pipeline embolization device.

BACKGROUND: Flow-diverting (FD) stents, with or without coiling, are a mainstay in endovascular treatment of intracranial aneurysms (IAs). One observed complication from flow diverter stent (FDS) insertion has been in-stent stenosis. Though previously studied in the short-term period, the long-term history of this complication has yet to be described. METHODS: We performed a retrospective cohort study of consecutive IAs treated with Pipeline Embolization Device (PED), with or without coiling, at our centre between September 2014 and December 2018 that had at least one digital subtraction angiogram (DSA) during follow-up. In-stent stenosis was measured from DSA images, and associated patient and procedural characteristics were analysed. RESULTS: 94 patients treated with PED for IA were identified. On initial DSA during follow-up, 52 patients (55.3%) had in-stent stenosis within the PED. Of these 52 patients, 17 had a second DSA during follow-up. In this 2nd DSA, improvement and/or stable in-stent stenosis was seen 16 patients (94.1%). One patient in this group had worsening in-stent stenosis had a vertebrobasilar junction FD stent. Of the patients without in-stent stenosis on initial DSA, 15 had a second DSA during follow-up. Only one of these patients (6.7%) had new appearance of in-stent stenosis (measuring 5%). Multivariate analysis found statin use to be predictive of in-stent stenosis (p = 0.020, Odds ratio = 0.279 and 95% confidence interval = 0.095-0.821). CONCLUSIONS: In-stent stenosis after FDS placement was seen in 53.2% of cases, which had between 1-50% of stenosis. 82.4% had resolution/improvement of their stenosis. Statin use was protective of in-stent stenosis.

Changing Enhancement Pattern and Tumor Volume of Vestibular Schwannomas After Subtotal Resection.

BACKGROUND: Surgical strategy in vestibular schwannomas may require subtotal resection to preserve neurologic function. Residual tumor growth pattern and contrast enhancement in the immediate postresection period remain uncertain. We sought to evaluate changes in the enhancement pattern and volume of vestibular schwannomas after subtotal resection in the immediate postoperative period. METHODS: Volumetric analysis of tumor size and enhancement patterns of vestibular schwannomas were measured on magnetic resonance imaging (MRI) scans obtained within 3 days of surgery, 3 months after surgery, and 1 year after surgery. RESULTS: Nineteen patients were eligible for inclusion in the study (9 male and 10 female) with an average age of 47 years. Contrast enhancement was absent in 6 of 19 (32%) of cases on the immediate postresection MRI with return of expected enhancement on subsequent studies. Volumetric analysis identified that tumors decreased in size by an average of 35% in the first 3 months (P = 0.025) after resection and 46% in the first year after resection (P < 0.01). CONCLUSIONS: Vestibular schwannomas that undergo subtotal resection tend to decrease in size over the first 3 months after resection. Residual tumor volume may fail to enhance on the immediate postresection MRI. Both of these findings could lead surgeons to misinterpret degree of resection after surgery and have implications for clinical decision making and research reporting in the scientific literature for vestibular schwannomas after subtotal resection.