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Intraoperative diagnosis is essential for providing safe and effective care during cancer surgery.sup.1. The existing workflow for intraoperative diagnosis based on hematoxylin and eosin staining of processed tissue is time, resource and labor intensive.sup.2,3. Moreover, interpretation of intraoperative histologic images is dependent on a contracting, unevenly distributed, pathology workforce.sup.4. In the present study, we report a parallel workflow that combines stimulated Raman histology (SRH).sup.5-7, a label-free optical imaging method and deep convolutional neural networks (CNNs) to predict diagnosis at the bedside in near real-time in an automated fashion. Specifically, our CNNs, trained on over 2.5 million SRH images, predict brain tumor diagnosis in the operating room in under 150 s, an order of magnitude faster than conventional techniques (for example, 20-30 min).sup.2. In a multicenter, prospective clinical trial (n = 278), we demonstrated that CNN-based diagnosis of SRH images was noninferior to pathologist-based interpretation of conventional histologic images (overall accuracy, 94.6% versus 93.9%). Our CNNs learned a hierarchy of recognizable histologic feature representations to classify the major histopathologic classes of brain tumors. In addition, we implemented a semantic segmentation method to identify tumor-infiltrated diagnostic regions within SRH images. These results demonstrate how intraoperative cancer diagnosis can be streamlined, creating a complementary pathway for tissue diagnosis that is independent of a traditional pathology laboratory. A prospective, multicenter, case-control clinical trial evaluates the potential of artificial intelligence for providing accurate bedside diagnosis of patients with brain tumors., Author(s): Todd C. Hollon [sup.1] , Balaji Pandian [sup.2] , Arjun R. Adapa [sup.2] , Esteban Urias [sup.2] , Akshay V. Save [sup.3] , Siri Sahib S. Khalsa [sup.1] , [...]

This document includes three abstracts from the Journal of Clinical & Translational Science. The first abstract discusses the development and validation of an artificial intelligence model to predict spinopelvic parameters in patients with adult spinal deformity. The second abstract examines the use of neuroimaging and hospitalization for transient ischemic attacks (TIAs) in the United States. The third abstract focuses on the prediction of dementia, disability, or death in elderly individuals using machine learning techniques. These abstracts provide valuable insights into the potential applications of artificial intelligence in healthcare and the management of various medical conditions. [Extracted from the article]

Rigorous computational fluid dynamics (CFD) codes can accurately simulate complex coupled processes within an arbitrary geometry. CFD can thus be a cost-effective and time-efficient method of guiding receiver design and testing for concentrating solar power technologies. However, it can be computationally prohibitive to include a large multifaceted dish concentrator or a field of hundreds or thousands of heliostats in the model domain. This paper presents a method to allow the CFD code to focus on a cavity receiver domain alone, by rigorously transforming radiance distributions calculated on the receiver aperture into radiance boundary conditions for the CFD simulations. This method allows the incoming radiation to interact with participating media such as falling solid particles in a high-temperature cavity receiver. The radiance boundary conditions of the CFD model can take into consideration complex beam features caused by sun shape, limb darkening, slope errors, heliostat facet shape, multiple heliostats, off-axis aberrations, atmospheric effects, blocking, shading, and multiple focal points. This paper also details implementation examples in ANSYS FLUENT for a heliostat field and a dish concentrator, which are validated by comparison to results from DELSOL and the ray-tracing code ASAP, respectively. [ABSTRACT FROM AUTHOR]

Objectives: To integrate morphological, haemodynamic and mechanical analysis of carotid atheroma driving plaque disruption., Materials and Methods: First, we analysed the phenotypes of carotid endarterectomy specimens in a photographic dataset A, and matched them with the likelihood of preoperative stroke. Second, laser angioscopy was used to further define the phenotypes in intact specimens (dataset B) and benchmark with histology. Third, representative vascular geometries for each structural phenotype were analysed with Computational Fluid Dynamics (CFD), and the mechanical strength of the complicated atheroma to resist penetrating forces was quantified (n=14)., Results: In dataset A (n=345), ulceration (fibrous cap disruption) was observed in 82% of all plaques, intraplaque haemorrhage in 68% (93% subjacent to an ulcer) and false luminal formation in 48%. At least one of these 'rupture' phenotypes was found in 97% of symptomatic patients (n=69) compared with 61% in asymptomatic patients. In dataset B (n=30), laser angioscopy redemonstrated the structural phenotypes with near-perfect agreement with histology. In CFD, haemodynamic stress showed a large pulse magnitude, highest upstream to the point of maximal stenosis and on ulceration the inflow stream excavates the necrotic core cranially and then recirculates into the true lumen. Based on mechanical testing (n=14), the necrotic core is mechanically weak and penetrated by the blood on fibrous cap disruption., Conclusions: Fibrous cap ulceration, plaque haemorrhage and excavation are sequential phenotypes of plaque disruption resulting from the chiselling effect of haemodynamic forces over unmatched mechanical tissue strength. This chain of events may result in thromboembolic events independently of the degree of stenosis., Competing Interests: Competing interests: EJS participates in royalty sharing with his employer related to angioscopy, the University of Washington, which has ownership of patents that may gain or lose financially through this publication. LS is the CMO of VerAvanti, company commercialising laser angioscopy., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Retropleural, retrodiaphragmatic, and retroperitoneal approaches are utilized to access difficult thoracolumbar junction (T10-L2) pathology. The authors present a 58-year-old man with chronic low-back pain who failed years of conservative therapy. Preoperative radiographs demonstrated significant levoconvex scoliosis with coronal and sagittal imbalance. He underwent a retrodiaphragmatic/retroperitoneal approach for T12-L1, L1-2, L2-3, and L3-4 interbody release and fusion in conjunction with second-stage facet osteotomies, L4-5 TLIF, and T10-iliac posterior instrumented fusion. This video focuses on the retrodiaphragmatic approach assisted by 3D navigation. The video can be found here: https://stream.cadmore.media/r10.3171/2022.3.FOCVID2215., Competing Interests: Disclosures Dr. Park reported personal fees from Globus, NuVasive, DePuy Synthes, and Accelus; and grants from DePuy Synthes, Cerapedics, SI-BONE, and ISSG, outside the submitted work.Dr. Park reported personal fees from Globus, NuVasive, DePuy Synthes, and Accelus; and grants from DePuy Synthes, Cerapedics, SI-BONE, and ISSG, outside the submitted work., (© 2022, The Authors.)

Background: Accurate specimen analysis of skull base tumors is essential for providing personalized surgical treatment strategies. Intraoperative specimen interpretation can be challenging because of the wide range of skull base pathologies and lack of intraoperative pathology resources., Objective: To develop an independent and parallel intraoperative workflow that can provide rapid and accurate skull base tumor specimen analysis using label-free optical imaging and artificial intelligence., Methods: We used a fiber laser-based, label-free, nonconsumptive, high-resolution microscopy method (<60 seconds per 1 × 1 mm2), called stimulated Raman histology (SRH), to image a consecutive, multicenter cohort of patients with skull base tumor. SRH images were then used to train a convolutional neural network model using 3 representation learning strategies: cross-entropy, self-supervised contrastive learning, and supervised contrastive learning. Our trained convolutional neural network models were tested on a held-out, multicenter SRH data set., Results: SRH was able to image the diagnostic features of both benign and malignant skull base tumors. Of the 3 representation learning strategies, supervised contrastive learning most effectively learned the distinctive and diagnostic SRH image features for each of the skull base tumor types. In our multicenter testing set, cross-entropy achieved an overall diagnostic accuracy of 91.5%, self-supervised contrastive learning 83.9%, and supervised contrastive learning 96.6%. Our trained model was able to segment tumor-normal margins and detect regions of microscopic tumor infiltration in meningioma SRH images., Conclusion: SRH with trained artificial intelligence models can provide rapid and accurate intraoperative analysis of skull base tumor specimens to inform surgical decision-making., (Copyright © Congress of Neurological Surgeons 2022. All rights reserved.)

Schwannomas are typically benign tumors that arise from the sheaths of nerves in the peripheral nervous system. In the spine, schwannomas usually arise from spinal nerve roots and are therefore extramedullary in nature. Surgical resection-achieving a gross total resection, is the main treatment modality and is typically curative for patients with sporadic tumors. In this video, we present the case of a 38-yr-old male with worsening left leg radiculopathy, found to have a lumbar schwannoma. Preoperative imaging demonstrated that the tumor was at the level of L4-L5. A laminectomy at this level was performed with gross total resection of the tumor. The key points of the video include use of intraoperative fluoroscopy to confirm surgical level and help plan surgical exposure, use of ultrasound for intradural tumor localization, and advocating for maximum safe resection using neurostimulation. The patient tolerated the surgery well without any complications. He was discharged home with no additional therapy needed. Appropriate patient consent was obtained., (© Congress of Neurological Surgeons 2021.)

Enabling technologies include surgical planning software, computer-assisted navigation, intraoperative three-dimensional (3D) imaging, and robotic systems. Presently, these technologies are in various stages of refinement. Spinal robots in particular are currently limited to the positioning of an alignment guide for pedicle screw placement. Current generation spinal robots, therefore, play a more limited role in spinal surgery. In contrast to spinal robots, intraoperative imaging technology has been developed further, to a stage that allows accurate 3D spinal image acquisition that can be readily utilized for spinal navigation. The integration of these various technologies has the potential to maximize the safety, consistency, reliability, and efficacy of surgical procedures. To that end, the trend for manufacturers is to incorporate various enabling technologies into the spinal robotic systems. In the near-term, it is expected that integration of more advanced planning software and navigation will result in wider applicability and value. In the long-term, there are a variety of enabling technologies such as augmented reality that may be a component of spinal robots. This article reviews the features of currently available spinal robots and discusses the likely future advancements of robotic platforms in the near- and long-term., (© Congress of Neurological Surgeons 2021.)

Myxopapillary ependymomas are slow-growing tumors that are located almost exclusively in the region of the conus medullaris, cauda equina, and filum terminale of the spinal cord. Surgical intervention achieving a gross total resection is the main treatment modality. If, however, a gross total resection cannot be achieved, surgery is augmented with radiation therapy. In this video, we present the case of a 27-yr-old male with persistent back pain and radiculopathy who was found to have a myxopapillary ependymoma that was adherent to the conus. Preoperative imaging demonstrated that the tumor was displacing the conus and nerve roots ventrally. A laminoplasty at L1-L2 was performed with near-total resection because of the intimate involvement of neural tissue. The key features of the video include performing laminoplasty and rationale, and performing maximum safe tumor resection with a combination of bipolar cautery, suction, and ultrasonic aspiration augmented with frequent stimulation, gel foam pledgets intradurally, and achieving a watertight closure of the dura and fascia. The patient tolerated the surgery well without any complications. Given his gross residual disease along the conus and young age, he was at a high risk for continued tumor growth without adjuvant therapy, with a recurrence rate of roughly 33% to 45% in patients who underwent subtotal resection. With the addition of adjuvant radiation therapy, the recurrence rate is 20% to 29%.1,2 He was discharged to home with a plan for conventional fractionated external beam radiation. At the most recent follow-up, he reported decreased back pain and radiculopathy. Appropriate patient consent was obtained., (© Congress of Neurological Surgeons 2021.)

Spondylolisthesis is a common cause of lower back and leg pain in adults. The initial treatment for patients is typically nonoperative in nature. However, when patients fail conservative management and their back and/or leg pain is recalcitrant, surgical intervention is warranted. Spinal decompression, either directly or indirectly, as well as fusion is often considered at this point. There are numerous approaches to fuse the spine, including anterior, lateral, or posterior, each with their own advantages and disadvantages.   This video illustrates a case of symptomatic spondylolisthesis occurring after laminectomy treated by lateral lumbar interbody fusion for indirect decompression and stabilization. The approach utilizes 3-dimensional navigation rather than traditional fluoroscopy, resulting in markedly decreased radiation exposure for the surgeon and staff while maintaining accuracy. Appropriate patient consent was obtained. This video demonstrates the technique for a lateral lumbar interbody fusion using navigation assistance, which is a minimally invasive technique for the treatment of spondylolisthesis., (Copyright © 2020 by the Congress of Neurological Surgeons.)

Lateral recess stenosis is a common cause of lumbar radiculopathy in adults. A lumbar nerve root travels in the lateral recess prior to exiting the spinal canal via the neural foramen. In the lateral recess, the traversing nerve root is susceptible to compression by the degenerative hypertrophy of the medial facet in addition to hypertrophied ligamentum flavum and herniated intervertebral disc.1 These degenerative changes are also typically associated with neural foraminal stenosis. Surgical treatment in unilateral cases consists of hemilaminectomy, medial facetectomy, foraminotomy, and, if applicable, microdiscectomy. In this video, we present a case of a 64-yr-old male presenting with progressive left L5 radiculopathy refractory to conservative management, with magnetic resonance imaging (MRI) findings of left L4-5 foraminal and lateral recess stenosis. We demonstrate the operative steps to complete a left L4-5 hemilaminectomy, medial facetectomy, foraminotomy, and microdiscectomy. Appropriate patient consent was obtained., (Copyright © 2020 by the Congress of Neurological Surgeons.)

Objective: The lateral lumbar interbody fusion (LLIF) technique is used to treat many common spinal degenerative pathologies including kyphoscoliosis. The use of spinal navigation for LLIF has not been broadly adopted, especially in adult spinal deformity. The purpose of this study was to evaluate the feasibility as well as the intraoperative and navigation-related complications of computer-assisted 3D navigation (CaN) during multiple-level LLIF for spinal deformity., Methods: Retrospective analysis of clinical and operative characteristics was performed for all patients > 18 years of age who underwent multiple-level CaN LLIF combined with posterior instrumentation for adult spinal deformity at the University of Michigan between 2014 and 2020. Intraoperative CaN-related complications, LLIF approach-related postoperative complications, and medical postoperative complications were assessed., Results: Fifty-nine patients were identified. The mean age was 66.3 years (range 42-83 years) and body mass index was 27.6 kg/m2 (range 18-43 kg/m2). The average coronal Cobb angle was 26.8° (range 3.6°-67.0°) and sagittal vertical axis was 6.3 cm (range -2.3 to 14.7 cm). The average number of LLIF and posterior instrumentation levels were 2.97 cages (range 2-5 cages) and 5.78 levels (range 3-14 levels), respectively. A total of 6 intraoperative complications related to the LLIF stage occurred in 5 patients. Three of these were CaN-related and occurred in 2 patients (3.4%), including 1 misplaced lateral interbody cage (0.6% of 175 total lateral cages placed) requiring intraoperative revision. No patient required a return to the operating room for a misplaced interbody cage. A total of 12 intraoperative complications related to the posterior stage occurred in 11 patients, with 5 being CaN-related and occurring in 4 patients (6.8%). Univariate and multivariate analyses revealed no statistically significant risk factors for intraoperative and CaN-related complications. Transient hip weakness and numbness were found to be in 20.3% and 22.0% of patients, respectively. At the 1-month follow-up, weakness was observed in 3.4% and numbness in 11.9% of patients., Conclusions: Use of CaN in multiple-level LLIF in the treatment of adult spinal deformity appears to be a safe and effective technique. The incidence of approach-related complications with CaN was 3.4% and cage placement accuracy was high.

Objective: Normal percentile growth charts for head circumference, length, and weight are well-established tools for clinicians to detect abnormal growth patterns. Currently, no standard exists for evaluating normal size or growth of cerebral ventricular volume. The current standard practice relies on clinical experience for a subjective assessment of cerebral ventricular size to determine whether a patient is outside the normal volume range. An improved definition of normal ventricular volumes would facilitate a more data-driven diagnostic process. The authors sought to develop a growth curve of cerebral ventricular volumes using a large number of normal pediatric brain MR images., Methods: The authors performed a retrospective analysis of patients aged 0 to 18 years, who were evaluated at their institution between 2009 and 2016 with brain MRI performed for headaches, convulsions, or head injury. Patients were excluded for diagnoses of hydrocephalus, congenital brain malformations, intracranial hemorrhage, meningitis, or intracranial mass lesions established at any time during a 3- to 10-year follow-up. The volume of the cerebral ventricles for each T2-weighted MRI sequence was calculated with a custom semiautomated segmentation program written in MATLAB. Normal percentile curves were calculated using the lambda-mu-sigma smoothing method., Results: Ventricular volume was calculated for 687 normal brain MR images obtained in 617 different patients. A chart with standardized growth curves was developed from this set of normal ventricular volumes representing the 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentiles. The charted data were binned by age at scan date by 3-month intervals for ages 0-1 year, 6-month intervals for ages 1-3 years, and 12-month intervals for ages 3-18 years. Additional percentile values were calculated for boys only and girls only., Conclusions: The authors developed centile estimation growth charts of normal 3D ventricular volumes measured on brain MRI for pediatric patients. These charts may serve as a quantitative clinical reference to help discern normal variance from pathologic ventriculomegaly.

The discovery of a new mass involving the brain or spine typically prompts referral to a neurosurgeon to consider biopsy or surgical resection. Intraoperative decision-making depends significantly on the histologic diagnosis, which is often established when a small specimen is sent for immediate interpretation by a neuropathologist. Access to neuropathologists may be limited in resource-poor settings, which has prompted several groups to develop machine learning algorithms for automated interpretation. Most attempts have focused on fixed histopathology specimens, which do not apply in the intraoperative setting. The greatest potential for clinical impact probably lies in the automated diagnosis of intraoperative specimens. Successful future studies may use machine learning to automatically classify whole-slide intraoperative specimens among a wide array of potential diagnoses.

Nerve root compression by foraminal pathology is challenging for a surgeon to decompress without violating the facet joint, which may necessitate a fusion procedure. One nonfusion approach to foraminal pathology is a combination intracanal approach for a laminotomy/foraminotomy followed by a paraspinal Wiltse approach for far lateral decompression. Unfortunately, even with the combination approach, it continues to be difficult to achieve adequate decompression without violating much of the facet joint overlying the nerve root. Spine endoscopy offers the ability to decompress the foraminal portion of the nerve without significant violation of the facet joint. We present a surgical video describing the technique for performing a percutaneous endoscopic contralateral L5-S1 foraminal decompression via an interlaminar approach, for a patient presenting with a left L5 radiculopathy due to L5-S1 foraminal stenosis. We explain the differences in the endoscopic channel docking point between ipsilateral and contralateral interlaminar approaches. The steps of an endoscopic foraminotomy are then described: dissect soft tissue and ligamentum flavum off the medial left S1 lamina and superior articulating process (SAP), undercut the superior articulating process of S1 and the inferior articulating process (IAP) of L5 with a drill, resect lateral ligamentum flavum off SAP and IAP exposing epidural fat, and finally dissect the left L5 nerve root and remove compressive lesions throughout its course in the lateral recess, foramen, and laterally. The presentation ends with an intraoperative photograph showing a decompressed L5 nerve root and postoperative imaging confirming this decompression. Appropriate patient consent was obtained., (Copyright © 2019 by the Congress of Neurological Surgeons.)

The conventional surgical approach to far lateral lumbar disk herniations is a paraspinal Wiltse approach. During the Wiltse approach, it is sometimes necessary to resect some of the facet or pars interarticularis to achieve an adequate exposure. The endoscopic transforaminal route can be of benefit in far lateral disk herniations due to direct access to the epidural space through Kambin's triangle, without the need for any bony removal or nerve retraction. In this video, we describe a percutaneous endoscopic transforaminal approach for far lateral discectomy in a patient presenting with a left L4 radiculopathy due to a far lateral L4-5 disk herniation. We describe Kambin's triangle anatomy and its relevance to the transforaminal route. The steps of the procedure are then described: dissection of soft tissue and removal of free disk fragments on the inferior aspect of the foramen far from the compressed exiting nerve route above to decrease the risk of retraction injury, gentle maneuvering of endoscope superiorly with removal of further compressive disk fragments, exposure of the exiting nerve root superiorly after adequate decompression is achieved and removal of any remaining fragments in close proximity to the nerve, and finally evaluation of traversing nerve root for any compressive lesions. The presentation ends with postoperative imaging confirming decompression of the far lateral disk herniation., (Copyright © 2019 by the Congress of Neurological Surgeons.)

Spinal cord herniation is an uncommon surgically treatable cause of thoracic myelopathy and progressive paraplegia. The thoracic spinal cord focally protrudes through a defect in the dura, resulting in progressive weakness, numbness, and spasticity affecting the lower extremities, in addition to possible urinary symptoms. In this video, we present the case of a 69-yr-old female who presented with 3 yr of progressive thoracic myelopathy due to a thoracic spinal cord herniation at T4-T5. We demonstrate the surgical steps to lyse arachnoid webs, mobilize the spinal cord, reduce the spinal cord herniation, and repair the dural defect. Appropriate patient consent was obtained., (Copyright © 2019 by the Congress of Neurological Surgeons.)

Spinal dural arteriovenous fistulas are diagnostically challenging lesions, and they are not well described in patients with a history of a spinal deformity correction. The authors present the challenging case of a 74-year-old woman who had previously undergone correction of a spinal deformity with subsequent revision. Several years after the last deformity operation, she developed a progressive myelopathy with urinary incontinence over a 6-month period. After evaluation at the authors' institution, an angiogram was obtained, demonstrating a fistula at the T12-L1 region. Surgical ligation of the fistula was performed with subsequent improvement of the neurological symptoms. This case is thought to represent the first fistula documented in an area of the spine that had previously been operated on, and to the authors' knowledge, it is the first case report to be associated with spinal deformity surgery. A brief historical overview and review of the pathophysiology of spinal dural arteriovenous fistulas is also included.

Cervical spondylotic myelopathy is a common cause of progressive quadriparesis in adults. It is characterized by compression of the cervical spinal cord due to degenerative changes including intervertebral disc protrusion, ligamentum flavum hypertrophy, and osteophyte formation. Clinically, patients can present with declining motor control in the extremities, gait imbalance, spasticity, hyperreflexia, or possibly frank weakness. Surgical treatment options include ventral and dorsal approaches, whose indications vary depending on spinal alignment, number of levels requiring decompression, the dorsal/ventral/circumferential location of compression, and patient-specific anatomic constraints. Posterior cervical decompression and instrumented fusion is a mainstay of treatment for cervical spondylotic myelopathy when a dorsal approach is indicated. In this video, we present a case of a 60-yr-old female who presented with signs and symptoms of cervical myelopathy, with MRI findings of C3 on C4 anterolisthesis and circumferential central stenosis worst at C4-5 and C5-6. We demonstrate the operative steps to complete a C3 to C6 decompression and instrumented fusion with lateral mass screws. Appropriate patient consent was obtained., (Copyright © 2018 by the Congress of Neurological Surgeons.)

OBJECTIVE Chiari malformation Type I (CM-I) is typically defined on imaging by a cerebellar tonsil position ≥ 5 mm below the foramen magnum. Low cerebellar tonsil position is a frequent incidental finding on brain or cervical spine imaging, even in asymptomatic individuals. Nonspecific symptoms (e.g., headache and neck pain) are common in those with low tonsil position as well as in those with normal tonsil position, leading to uncertainty regarding appropriate management for many patients with low tonsil position and nonspecific symptoms. Because cerebellar tonsil position is not strictly correlated with the presence of typical CM-I symptoms, the authors sought to determine if other 2D morphometric or 3D volumetric measurements on MRI could distinguish between patients with asymptomatic and symptomatic CM-I. METHODS The authors retrospectively analyzed records of 102 pediatric patients whose records were in the University of Michigan clinical CM-I database. All patients in this database had cerebellar tonsil position ≥ 5 mm below the foramen magnum. Fifty-one symptomatic and 51 asymptomatic patients were matched for age at diagnosis, sex, tonsil position, and tonsil morphology. National Institutes of Health ImageJ software was used to obtain six 2D anatomical MRI measurements, and a semiautomated segmentation tool was used to obtain four 3D volumetric measurements of the posterior fossa and CSF subvolumes on MRI. RESULTS No significant differences were observed between patients with symptomatic and asymptomatic CM-I related to tentorium length (50.3 vs 51.0 mm; p = 0.537), supraoccipital length (39.4 vs 42.6 mm; p = 0.055), clivus-tentorium distance (52.0 vs 52.1 mm; p = 0.964), clivus-torcula distance (81.5 vs 83.3 mm; p = 0.257), total posterior fossa volume (PFV; 183.4 vs 190.6 ml; p = 0.250), caudal PFV (152.5 vs 159.8 ml; p = 0.256), fourth ventricle volume to caudal PFV ratio (0.0140 vs 0.0136; p = 0.649), or CSF volume to caudal PFV ratio (0.071 vs 0.061; p = 0.138). CONCLUSIONS No clinically useful 2D or 3D measurements were identified that could reliably distinguish pediatric patients with symptoms attributable to CM-I from those with asymptomatic CM-I.

OBJECTIVE Previous studies have indicated an association of Chiari malformation Type I (CM-I) and a small posterior fossa. Most of these studies have been limited by 2D quantitative methods, and more recent studies utilizing 3D methodologies are time-intensive with manual segmentation. The authors sought to develop a more automated tool to calculate the 3D posterior fossa volume, and correlate its changes after decompression with surgical outcomes. METHODS A semiautomated segmentation program was developed, and used to compare the pre- and postoperative volumes of the posterior cranial fossa (PCF) and the CSF spaces (cisterna magna, prepontine cistern, and fourth ventricle) in a cohort of pediatric patients with CM-I. Volume changes were correlated with postoperative symptomatic improvements in headache, syrinx, tonsillar descent, cervicomedullary kinking, and overall surgical success. RESULTS Forty-two pediatric patients were included in this study. The mean percentage increase in PCF volume was significantly greater in patients who showed clinical improvement versus no improvement in headache (5.89% vs 1.54%, p < 0.05) and tonsillar descent (6.52% vs 2.57%, p < 0.05). Overall clinical success was associated with a larger postoperative PCF volume increase (p < 0.05). These clinical improvements were also significantly associated with a larger increase in the volume of the cisterna magna (p < 0.05). The increase in the caudal portion of the posterior fossa volume was also larger in patients who showed improvement in syrinx (6.63% vs 2.58%, p < 0.05) and cervicomedullary kinking (9.24% vs 3.79%, p < 0.05). CONCLUSIONS A greater increase in the postoperative PCF volume, and specifically an increase in the cisterna magna volume, was associated with a greater likelihood of clinical improvements in headache and tonsillar descent in patients with CM-I. Larger increases in the caudal portion of the posterior fossa volume were also associated with a greater likelihood of improvement in syrinx and cervicomedullary kinking.