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Intraoperative diagnosis is essential for providing safe and effective care during cancer surgery1. The existing workflow for intraoperative diagnosis based on hematoxylin and eosin staining of processed tissue is time, resource and labor intensive2,3. Moreover, interpretation of intraoperative histologic images is dependent on a contracting, unevenly distributed, pathology workforce4. In the present study, we report a parallel workflow that combines stimulated Raman histology (SRH)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)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.

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 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.)