Incidence and risk factors of postoperative symptomatic spinal epidural hematoma in cervical spine surgery: a single center, retrospective study of 18,220 patients.

PURPOSE: The goal of this research is to explore the incidence and risk factors of symptomatic spinal epidural hematoma (SSEH) following cervical spine surgery. METHODS: Patients with SSEH from January 2009 to February 2019 were identified as hematoma group. Two control subjects without SSEH were randomly selected for each patient in SSEH group as control group. We collected gender, age, body mass index (BMI), ossification of the posterior ligament (OPLL), comorbidities, anti-platelet or anti-coagulate treatment, coagulation function, segments, instrumental fixation, surgical approach, surgical procedure, duration of surgery and estimated blood loss, which might affect the occurrence of symptomatic epidural hematoma. T-test and Chi-square test were used to univariable test. Multifactor logistic regression analysis was used to investigate the correlation with symptomatic epidural hematoma, furthermore its causes were explored. RESULTS: Among 18,220 patients, 43 subjects developed SSEH, the incidence was 0.24%. The median time from the end of index surgery to SSEH was 150  min (25 and 75 percentile: 85  min to 290  min). The neurologic function before evacuation by modified Frankel scale is grade B in 5 patients, C in 32 patients, grade D in 6 patients. All patients' symptoms relieved partially or completely after evacuation. All patients with neurologic deficit worse than grade C pre-evacuation had at least one-grade improvement except for one patient. Multifactor logistic regression revealed OPLL involved segments are significantly correlated to the incidence of postoperative symptomatic epidural hematoma (P < 0.05), with a cut-off value of 1.5 levels. CONCLUSION: OPLL involved segments are significantly correlated to the incidence of postoperative symptomatic epidural hematoma.

Single versus dual operative spine fractures in ankylosing spondylitis.

OBJECTIVE: Ankylosing spondylitis, the most common spondyloarthritis, fuses individual spinal vertebrae into long segments. The unique biomechanics of the ankylosed spine places patients at unusually high risk for unstable fractures secondary to low-impact mechanisms. These injuries are unique within the spine trauma population and necessitate thoughtful management. Therefore, the authors aimed to present a richly annotated data set of operative AS spine fractures with a significant portion of patients with simultaneous dual noncontiguous fractures. METHODS: Patients with ankylosing spondylitis with acute fractures who received operative management between 2012 and 2020 were reviewed. Demographic, admission, surgical, and outcome parameters were retrospectively collected and reviewed. RESULTS: In total, 29 patients were identified across 30 different admissions. At admission, the mean age was 71.7 ± 11.8 years. The mechanism of injury in 77% of the admissions was a ground-level fall; 30% also presented with polytrauma. Of admissions, 50% were patient transfers from outside hospitals, whereas the other half presented primarily to our emergency departments. Fifty percent of patients sustained a spinal cord injury, and 35 operative fractures were identified and treated in 32 surgeries. The majority of fractures clustered around the cervicothoracic (C4-T1, 48.6%) and thoracolumbar (T8-L3, 37.11%) junctions. Five patients (17.2%) had simultaneous dual noncontiguous operative fractures; these patients were more likely to have presented with a higher-energy mechanism of injury such as a bicycle or motor vehicle accident compared with patients with a single operative fracture (60% vs 8%, p = 0.024). On preoperative MRI, 56.3% of the fractures had epidural hematomas (EDHs); 25% were compressive of the underlying neural elements, which dictated the number of laminectomy levels performed (no EDH, 2.1 ± 2.36; noncompressive EDH, 2.1 ± 1.85; and compressive EDH, 7.4 ± 4 [p = 0.003]). The mean difference in instrumented levels was 8.7 ± 2.6 with a mean estimated blood loss (EBL) of 1183 ± 1779.5 mL. Patients on a regimen of antiplatelet therapy had a significantly higher EBL (2635.7 mL vs 759.4 mL, p = 0.015). Overall, patients had a mean hospital length of stay of 15.2 ± 18.5 days; 5 patients died during the same admission or after transfer to an outside hospital. Nine of 29 patients (31%) had died by the last follow-up (the mean follow-up was 596.3 ± 878.9 days). CONCLUSIONS: Patients with AS who have been found to have unstable spine fractures warrant a thorough diagnostic evaluation to identify secondary fractures as well as compressive EDHs. These patients experienced prolonged inpatient hospitalizations with significant morbidity and mortality.

Atypical Teratoid/Rhabdoid Tumor of the Conus Medullaris.

INTRODUCTION: Atypical teratoid/rhabdoid tumor (AT/RT) is a rare tumor of the central nervous system, especially when involving the spinal column or spinal cord. CASE PRESENTATION: We present a case of a 5-year-old girl with progressive bilateral lower extremity pain found to have a discrete nodular lesion of the conus with mild heterogeneous enhancement. Surgical decompression and resection demonstrated a pathologic tumor consistent with AT/RT with loss of INI1 protein on immunohistochemistry. DISCUSSION AND CONCLUSION: AT/RT lesions of the conus medullaris are exceedingly rare and associated with extensive disease. We report a rare case of AT/RT with selective involvement of the conus medullaris, as well as describe the surgical, radiographic, and pathologic findings of this tumor.

Surgical considerations in posterior C1-2 instrumentation in the presence of vertebral artery anomalies: case illustration and review of literature.

Vascular anomalies involving the V3 segment of the vertebral artery are common and may complicate posterior atlantoaxial instrumentation. We report a patient with a fenestrated vertebral artery that underwent successful C1-2 instrumentation and fusion. Various vertebral artery anomalies are discussed with a review of pertinent literature.

Quantitative and qualitative analyses of spinal canal encroachment during cervical laminectomy using the kerrison rongeur versus High-Speed burr.

BACKGROUND: Several cervical laminectomy techniques have been described. One commonly used method involves making bilateral trough laminotomies using either a Kerrison rongeur or a high speed burr, and then removing the lamina en-bloc. Alternatively, some surgeons prefer to thin the lamina with the burr, and then remove the lamina in a piecemeal fashion using Kerrison rongeurs. Some surgeons have warned against the potential risk of iatrogenic spinal cord injury from inserting the Kerrison footplate into a stenotic canal. We aim to quantify the amount of canal encroachment for various methods of cervical laminectomies. METHODS: Three attending spine surgeons and two fellows each performed laminectomies using C5 sawbones models. The canal was completely filled with modeling putty to simulate a stenotic spinal cord. Bilateral trough laminotomies were performed using a 1 mm Kerrison, a 2 mm Kerrison, and a 3 mm matchstick high-speed burr. Piecemeal laminectomies were performed with a 2 mm Kerrison. A blinded spine surgery fellow performed all quantitative measurements. Three blinded researchers qualitatively ranked the amount of "canal encroachment". RESULTS: The average canal encroachment was 0.50 ± 0.45mm for the burr, 1.37 ± 0.68 mm for the 1 mm Kerrison, and 1.47 ± 0.37 mm for the 2 mm Kerrison (p = .002). There was a statistically significant difference between the burr and 1 mm Kerrison (p = .01) and between the burr and the 2 mm Kerrison (p = .001). There was no statistical difference between the 1 mm and 2 mm Kerrison (p = .78). The mean rank of the burr group, the Kerrison rongeur group, and the piecemeal group were 1.41, 1.94, and 2.65, respectively, on an ordinal scale of 1-3. CONCLUSION: When performing a trough laminotomy, the high-speed burr results in less canal encroachment compared to 1 mm or 2 mm Kerrison rongeurs. In the setting of a stenotic spinal canal, spine surgeons should consider using the burr to perform laminectomy to minimize the degree of canal encroachment.

Anterior cervical osteotomy: operative technique.

PURPOSE: Correction of rigid cervical deformities often requires osteotomies to realign the spine. Cervical pedicle subtraction osteotomy can be technically challenging due to the presence of cervical nerve roots and usually can only be performed at C7 or T1 due to the presence of vertebral arteries. In contrast, anterior cervical osteotomy can be performed throughout the cervical spine and is a safe and effective method for correction of both sagittal and coronal cervical deformities. We describe the anterior cervical osteotomy technique with a review of the pertinent literature. METHODS: A step-by-step technical guide for anterior cervical osteotomy is provided with a focus on surgical nuances and complication avoidance. Two illustrative cases of fixed sagittal and coronal deformities are included to demonstrate the substantial amount of deformity correction achievable using the anterior cervical osteotomy technique. RESULTS: Both patients in the illustrative cases had successful clinical and radiographic outcome following deformity correction utilizing the anterior cervical osteotomy technique. CONCLUSION: Anterior cervical osteotomy is a safe and effective technique for correction of rigid cervical deformities. Spine surgeons should be familiar with this technique to optimize clinical outcome in patients undergoing cervical deformity correction.

Anterior Temporal Sulcus: A Reliable Intraoperative Landmark for Accurately Delineating the Superior Limit of Amygdala Resection during Anterior Temporal Lobectomy.

BACKGROUND: Reliable anatomical landmarks are essential to avoiding injuries to the optic tract, anterior choroidal artery and basal ganglia during anterior temporal lobectomy (ATL). We describe an anatomic landmark, specifically the anterior temporal sulcus (ATS), as a reliable method to define the anterior portion of the endorhinal sulcus and the superior limit of amygdala resection. METHODS: A total of 25 consecutive patients undergoing ATL at Rush University Medical Center (RUMC) were identified, and their preoperative brain magnetic resonance imaging (MRI) studies were analyzed. RESULTS: All patients underwent successful ATL without any complication. There was no injury to the optic tract, anterior choroidal artery or basal ganglia using ATS as the landmark for the superior limit of amygdala resection. The ATS was clearly identifiable on coronal preoperative MRI in 48 out of 50 temporal lobes (96%). The ATS was present in all 25 left temporal lobes (100%); 2 of the 25 right temporal lobes had absent ATS (8%). Following the ATS posteriorly on coronal MRI, it led to the endorhinal sulcus and accurately predicted the superior extent of amygdala resection in all 25 patients (48 temporal lobes). CONCLUSION: The ATS is a reliable anatomical landmark that accurately delineates the superior border of the amygdala during ATL.

Magnetic resonance imaging characteristics of typical and atypical/anaplastic meningiomas - Case series and literature review.

OBJECTIVE: The histologic grades of meningiomas have a significant impact on the risk of recurrence, prognosis, and the need for adjuvant treatment such as radiation therapy. The purpose of this study is to investigate the magnetic resonance imaging (MRI) characteristics of typical and atypical/anaplastic meningiomas. METHODS: The medical records of 32 consecutive patients who underwent meningioma resections between April 2004 and November 2006 were retrospectively reviewed. Preoperative MR studies were reviewed by board-certified neuroradiologists. Both univariate and multivariate analyses were used to analyze the MR characteristics of the typical and atypical/anaplastic meningiomas. A review of pertinent literature was also conducted. RESULTS: Thirty-two patients were identified during the study period. Histopathologic examination of the surgical specimens revealed 27 (84.4% - Group I) typical meningiomas and 5 (15.6% - Group 2) atypical/anaplastic meningiomas. The chi-square test showed that restricted diffusion was much more likely to be present in Group 2 (p < 0.01), and the choline-to-creatinine (Cho/Cr) ratio was significantly higher in Group 2 (8.8 vs. 5.1, p = 0.01). The multivariate analysis confirmed that the atypical/anaplastic group is much more likely to have restricted diffusion (p = 0.02) and higher Cho/Cr ratios (p = 0.03). CONCLUSION: Meningiomas with restricted diffusion and higher Cho/Cr ratio on MR spectroscopy are more likely to be atypical/anaplastic types. Preoperative MRI utilizing these sequences can provide important information which can be valuable to counsel patients regarding prognosis, risk of recurrence and the need for adjuvant radiation in addition to surgical resection.

Biomechanical effects of the transcondylar approach on the craniovertebral junction.

The transcondylar variation of the far-lateral, retrosigmoid approach is intended for pathologies in the anterolateral portion of the foramen magnum. That area is more clearly visualized when a fraction of the ipsilateral occipital condyle is removed. In this study, the biomechanical effect of this approach on occiput-C2 rotation was investigated. Our hypothesis was that the biomechanical characteristics are significantly altered following the transcondylar approach. Five human cadaveric upper cervical spine specimens (occiput-C7) were used in the study. Torsional moments were applied from zero to a maximum of 1.5 N m to the left and to the right using a mechanical testing machine. The resulting rotational motions of the O-C1, C1-2, and O-C2 segments were measured in the intact specimen and after a simulated right-sided transcondylar approach with resection of 2/3 of the condyle, confirmed by CT scanning and visual inspection. After the posterior two-thirds of the occipital condyle were removed, the neutral zone (NZ) increased 1.3° to the left and 2° to the right at C0-C1, and 7.4° to the left and 6.2° to the right at C1-2. The cumulative increase in NZ between O and C2 was 8.7° to the left and 8.2° to the right. The transcondylar approach also resulted in significant increases in range of motion (ROM) in axial rotation to both sides in all segments. ROM increased 2.8° to the left and 2.4° to the right between C0 and C1, 7.3° to the left and 5.4° to the right between C1 and C2, and 10.1° to the left and 7.8° to the right between CO and C2. Upon inspection, the area of the occipital condyle where the alar ligament attaches had been completely removed in three of the five specimens. Removing the posteromedial two-thirds of one occipital condyle alters the normal axial rotational movements of the craniovertebral junction on both sides. The insertion of the alar ligament can be inadvertently removed during condylar resection, and this could contribute to atlanto-axial instability. There is a biomechanical substrate to cranio-cervical instability following a transcondylar approach; these patients may need to be followed over several years to ensure it does not progress and necessitate occipito-cervical fusion.

Retrosigmoid approach for resection of an extraventricular choroid plexus papilloma in the cerebellopontine angle.

Choroid plexus papillomas (CPP) are uncommon benign brain tumors that usually arise in the fourth ventricle in adults and lateral ventricles in children. Extraventricular CPPs are rare and can be found primarily in the cerebellopontine angle (CPA). We present a case of primary extraventricular CPP in the right CPA successfully resected with retrosigmoid approach. Detailed surgical techniques of retrosigmoid craniotomy and tumor dissection are presented in high definition video with narration. The video can be found here: http://youtu.be/6591en3nWlY .

Retrosigmoid approach for resection of cerebellopontine angle meningioma and decompression of the trigeminal nerve.

Cerebellopontine angle (CPA) lesions account for up to 10% of all intracranial tumors. The most common CPA lesions are vestibular schwannomas (70-80%), meningiomas (10-15%) and epidermoid cysts (5%). CPA tumors are estimated to be the secondary cause for up to 9.9% patients with trigeminal neuralgia. We demonstrate a case of medically refractory trigeminal neuralgia caused by a CPA meningioma that was successfully treated via retrosigmoid approach. The patient had immediate and dramatic symptomatic improvement after surgery. Detailed surgical techniques of retrosigmoid craniotomy and tumor dissection are presented in high definition video with narration. The video can be found here: http://youtu.be/55j9QCQEsH8 .

Minimally invasive surgery for synchronous, same-level lumbar intradural-extramedullary neoplasm and acute disc herniation.

Schwannomas are the most common intradural-extramedullary spinal tumors, with an estimated incidence of 3 to 10 cases per 100,000 people. With continued advances in minimally invasive surgery (MIS) over recent years, MIS techniques have been utilized by spine surgeons in the resection of intradural spinal neoplasms with favorable surgical results and clinical outcomes. This video demonstrates a rare case of symptomatic, synchronous, same-level lumbar intradural-extramedullary neoplasm and acute disc herniation, both of which were successfully treated using a single MIS approach. Surgical pearls and nuances are discussed to better delineate technique and minimize potential complications. The video can be found here: http://youtu.be/78ibbicBRUk.

Surgical resection of subependymoma of the cervical spinal cord.

Subependymomas can rarely occur in the spinal cord, and account for about 2% of symptomatic spinal cord tumors. It most often occurs in the cervical spinal cord, followed by cervicothoracic junction, thoracic cord and conus medullaris. It often has an eccentric location in the spinal cord and lacks gadolinium enhancement on magnetic resonance imaging. We present a rare case of symptomatic subependymoma of the cervical spinal cord, which underwent successful gross total resection. Surgical pearls and nuances are discussed to help surgeons to avoid potential complications. The video can be found here: http://youtu.be/Rsm9KxZX7Yo.

Y-stent-assisted coil embolization of cerebral aneurysms.

Y-stent-assisted coiling is a technique used by neuroendovascular surgeons to treat complex, wide-necked, bifurcation aneurysms in locations such as basilar tip and middle cerebral artery bifurcation. Several recent studies have demonstrated low complication rate and favorable clinical and angiographic outcomes. The Y-stent technique is illustrated here in detail and the intraoperative nuances are also discussed to minimize potential complications associated with technique. The video can be found here: http://youtu.be/77pEmqx_fyQ .

Endovascular transarterial embolization of cerebral arteriovenous malformation with ethylene-vinyl alcohol copolymer.

Cerebral arteriovenous malformations (AVMs) have an estimated 2-4% annual risk of hemorrhage. Treatment options for AVMs include microsurgical resection, stereotactic radiosurgery, and endovascular embolization. As endovascular technology and techniques continue to advance and mature, endovascular embolization is becoming an increasingly vital component of AVM treatment not only as a presurgical treatment to reduce microsurgical risks, but also as a stand-alone curative method in some cases. This case illustrates the successful and curative transarterial embolization of a right frontal AVM in a 17-year-old boy with ethylene-vinyl alcohol copolymer (Onyx). The video can be found here: http://youtu.be/L4hE1MvCZCY .

Disseminated spinal myxopapillary ependymoma in an adult at initial presentation: a case report and review of the literature.

Disseminated spinal myxopapillary ependymoma (MPE) is extremely rare in adults. We report a 63-year-old man with chronic low-back pain found to have multiple MPEs in the thoracic, lumbar and sacral spine. Diagnostic and management strategies of disseminated MPE are discussed with a review of pertinent literature.

Risk factors for C5 palsy: a systematic review and multivariate analysis.

OBJECTIVE: Postoperative C5 palsy (C5P) is a known complication in cervical spine surgery. However, its exact pathophysiology is unclear. The authors aimed to provide a review of the current understanding of C5P by performing a comprehensive, systematic review of the existing literature and conducting a critical appraisal of existing evidence to determine the risk factors of C5P. METHODS: A systematic search of PubMed/MEDLINE (January 1, 2019, to July 2, 2021), EMBASE (inception to July 2, 2021), and Cochrane (inception to July 2, 2021) databases was conducted. Preestablished criteria were used to evaluate studies for inclusion. Studies that adjusted for one or more of the following factors were considered: preoperative foraminal diameter (FD) at C4/5, posterior spinal cord shift at C4/5, preoperative anterior-posterior diameter (APD) at C4/5, preoperative spinal cord rotation, and change in C2-7 Cobb angle. Studies were rated as good, fair, or poor based on the Quality in Prognosis Studies (QUIPS) tool. Random effects meta-analyses were done using methods outlined by Cochrane methodologists for pooling of prognostic studies. Overall quality (strength) of evidence was based on Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methods for prognostic studies. The protocol for this review was published on the PROSPERO (CRD264358) website. RESULTS: Of 303 potentially relevant citations of studies, 12 met the inclusion criteria set a priori. These works provide moderate-quality evidence that preoperative FD substantially increases the odds of C5P in patients undergoing posterior cervical surgery. Pooled estimates across 7 studies in which various surgical approaches were used indicate that the odds of C5P approximately triple for each millimeter decrease in preoperative FD (OR 3.05, 95% CI 2.07-4.49). Preoperative APD increases the odds of C5P, but the confidence is low. Across 3 studies, each using different surgical approaches, each millimeter decrease in preoperative APD was associated with a more than 2-fold increased odds of C5P (pooled OR 2.51, 95% CI 1.69-3.73). Confidence that there is an association with postoperative C5P and posterior spinal cord shift, change in sagittal Cobb angle, and preoperative spinal cord rotation is very low. CONCLUSIONS: The exact pathophysiological process resulting in postoperative C5P remains an enigma but there is a clear association with foraminal stenosis, especially when performing posterior procedures. C5P is also related to decreased APD but the association is less clear. The overall quality (strength) of evidence provided by the current literature is low to very low for most factors. Systematic review registration no.: CRD264358 (https://www.crd.york.ac.uk/prospero/).

Minimally invasive transpedicular approach for evacuation of epidural abscess and debridement of disc space in a patient with discitis in the thoracic spine.

Spinal epidural abscess (SEA) often requires prompt surgical decompression to prevent potential devastating neurological deficits. Dorsally located SEA usually can be evacuated via simple laminectomies. Ventral SEA often requires an anterior approach such as thoracotomy to achieve adequate exposure and decompression. We report a case of ventral thoracic SEA associated with discitis and osteomyelitis that was successfully treated via minimally invasive transpedicular approach. The patient had immediate and dramatic symptomatic improvement and was ambulatory on post-operative Day 1. The minimally invasive transpedicular approach avoids the surgical morbidity associated with anterior approach and is effective surgical alternative to treat ventral SEA. The video can be found The video can be found here: http://youtu.be/do-K1VWYhi4.

Minimally invasive treatment of spinal dural arteriovenous fistula with the use of intraoperative indocyanine green angiography.

Spinal dural arteriovenous fistula (dAVF) is the most common vascular malformation of the spinal cord. Traditionally it is treated by the standard muscle-splitting midline approach with bilateral laminectomies extending from one level above to one level below the dAVF. We present a minimally invasive approach for ligation of dAVF with concurrent use of intraoperative indocyanine green (ICG) angiography. Minimally invasive watertight dural closure technique is also demonstrated and discussed. The minimally invasive approach with intraoperative ICG results in quicker recovery, early mobilization and shorter hospital stay compared to traditional open approach. The video can be found here: http://youtu.be/mNUeJKLxL3Q.