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Background: There has been heightened interest in performing percutaneous lumbar interbody fusions (percLIFs) through Kambin's triangle, an anatomic corridor allowing entrance into the disc space. However, due to its novelty, there are limited data regarding the long-term benefits of this procedure. Our objective was to determine the long-term efficacy and durability of the percutaneous insertion of an expandable titanium cage through Kambin's triangle without facetectomy., Methods: A retrospective review of patients undergoing percLIF via Kambin's triangle using an expandable titanium cage was performed. Demographics, visual analog scale (VAS) scores, Oswestry Disability Index (ODI), radiographic measurements, perioperative variables, and complications were recorded. VAS, ODI, and radiographic measurements were compared with baseline using the generalized estimating equations assuming normally distributed data. Fusion was assessed with computed tomography (CT) at 1 and 2 years after the procedure., Results: A total of 49 patients were included. Spondylolisthesis, lumbar lordosis (LL), sacral slope, pelvic tilt, and anterior/posterior disc space height were all significantly improved postoperatively at each time point of 3, 6, 12, and 24 months ( P < 0.001). Pelvic incidence-LL mismatch decreased significantly at each follow-up ( P < 0.001) with a mean reduction of 4° by 24 months. VAS back scores reduced by >2 points at the 6, 12, and 24 month follow-ups. ODI scores reduced by >15 points at the 12- and 24-month follow-ups. Of the patients who had 1- and 2-year CT images, fusion rates at those time points were 94.4% (17/18) and 87.5% (7/8), respectively. The mean annual rate of surgically significant adjacent segment disease was 2.74% through an average follow-up of 2.74 years., Conclusion: These results highlight that percLIF, a procedure done without an endoscope or facetectomy, can be performed using an expandable titanium cage through Kambin's triangle with excellent radiographic and clinical results., Clinical Relevance: percLIF via Kambin's triangle is a safe and succesful procedure with long-term improvements in both clinical and radiographic outcomes., Competing Interests: Declaration of Conflicting Interests : Dr Abd-El-Barr is a consultant for Spineology, TrackX, and Depuy. Dr Shaffrey has financial relationships with NuVasive, Medtronic, SI Bone, and Proprio. Dr Wiggins is a strategic advisor for Qure.ai. Dr Chi discloses consulting fees from DePuy and K2M. The authors report that there are no other relevant disclosures pertaining to the content of this manuscript., (This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery. Copyright © 2023 ISASS. To see more or order reprints or permissions, see http://ijssurgery.com.)

Background: Enterothecal fistulas are pathological connections between the gastrointestinal system and subarachnoid space. These rare fistulas occur mostly in pediatric patients with sacral developmental anomalies. They have yet to be characterized in an adult born without congenital developmental anomaly yet must remain on the differential diagnosis when all other causes of meningitis and pneumocephalus have been ruled out. Good outcomes rely on aggressive multidisciplinary medical and surgical care, which are reviewed in this manuscript., Case Description: A 25-year-old female with history of a sacral giant cell tumor resected via anterior transperitoneal approach followed by posterior L4-pelvis fusion presented with headaches and altered mental status. Imaging revealed that a portion of small bowel had migrated into her resection cavity and created an enterothecal fistula resulting in fecalith within the subarachnoid space and florid meningitis. The patient underwent a small bowel resection for fistula obliteration, and subsequently developed hydrocephalus requiring shunt placement and two suboccipital craniectomies for foramen magnum crowding. Ultimately, her wounds became infected requiring washouts and instrumentation removal. Despite a prolonged hospital course, she made significant recovery and at 10-month following presentation, she is awake, oriented, and able to participate in activities of daily living., Conclusions: This is the first case of meningitis secondary to enterothecal fistula in a patient without a previous congenital sacral anomaly. Operative intervention for fistula obliteration is the primary treatment and should be performed at a tertiary hospital with multidisciplinary capabilities. If recognized quickly and appropriately treated, there is a possibility of good neurological outcome., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jss.amegroups.com/article/view/10.21037/jss-22-89/coif). The authors have no conflicts of interest to declare., (2023 Journal of Spine Surgery. All rights reserved.)

Objective: While Kambin's Triangle has become an ever more important anatomic window given its proximity to the exiting nerve root, there have been limited studies examining the effect of disease on the corridor. Our goal was to better understand how pathology can affect Kambin's Triangle, thereby altering the laterality of approach for percutaneous lumbar interbody fusion (percLIF)., Methods: The authors performed a single-center retrospective review of patients evaluated for percLIF. The areas of Kambin's Triangle were measured without and with nerve segmentation. For the latter, the lumbosacral nerve roots on 3-dimensional T2 magnetic resonance imaging were manually segmented. Next, the borders of Kambin's Triangle were delineated, ensuring no overlap between the area and nerve above., Results: Fifteen patients (67.5 ± 9.7 years, 46.7% female) were retrospectively reviewed. We measured 150 Kambin's Triangles. The mean areas from L1-S1 were 50.0 ± 12.3 mm 2 , 73.8 ± 12.5 mm 2 , 83.8 ± 12.2 mm 2 , 88.5 ± 19.0 mm 2 , and 116 ± 29.3 mm 2 , respectively. When pathology was present, the areas significantly decreased at L4-L5 (P = 0.046) and L5-S1 (P = 0.049). Higher spondylolisthesis and smaller posterior disk heights were linked with decreased areas via linear regression analysis (P < 0.05). When nerve segmentation was used, the areas were significantly smaller from L1-L5 (P < 0.05). Among 11 patients who underwent surgery, none suffered from postoperative neuropathies., Conclusions: These results illustrate the feasibility of preoperatively segmenting lumbosacral nerves and measuring Kambin's Triangle to help guide surgical planning and determine the ideal laterality of approach for percLIF., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: The accuracy of pedicle screws placed with instrument tracking and robotic navigation are individually comparable or superior to placement using standard fluoroscopy, however head-to-head comparisons between these adjuncts in a similar surgical population have yet to be performed., Methods: Consecutive patients undergoing percutaneous thoracic and lumbosacral spinal instrumentation were retrospectively enrolled. Instrumentation was performed using either fluoroscopy-based instrument tracking system (TrackX, TrackX Technologies) or robotic-navigation (ExcelsiusGPS, Globus Medical). Postinstrumentation computed tomography scans were graded for breach according to the Gertzbein-Robbins scale, with "acceptable" screws deemed as Grade A or B and "unacceptable" screws deemed as Grades C through E. Accuracy data was compared between both instrumentation modalities., Results: Fifty-three patients, comprising a total of 250 screws (167 robot, 83 instrument tracking) were included. The overall accuracy between both modalities was similar, with 96.4% and 97.6% of screws with acceptable accuracy between instrument tracking and robotic navigation, respectively (I-squared 0.30, df = 1, P = 0.58). Between instrument tracking and robotic navigation, 92.8% and 95.8% of screws received Grade A, 3.6% and 1.8% a Grade B, 1.2% and 1.2% a Grade C, 1.2% and 0.6% a Grade D, and 1.2% and 0.6% a Grade E, respectively. The robot was abandoned intraoperatively in 2 cases due to unrecoverable registration inaccuracy or software failure, leading to abandonment of 8 potential screws (4.8%)., Conclusions: In a similar patient population, there is a similarly high degree of instrumentation accuracy between fluoroscopy-based instrument tracking and robotic navigation. There is a rare chance for screw breach with either surgical adjunct., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Purpose: Prone transpsoas fusion (PTP) is a minimally invasive technique that maximizes the benefit of lateral access interbody surgery and the prone positioning for surgically significant adjacent segment disease. The authors describe the feasibility, reproducibility and radiographic efficacy of PTP when performed for cases of lumbar ASD., Methods: Adult patients undergoing PTP for treatment of lumbar ASD at three institutions were retrospectively enrolled. Demographic information was recorded, as was operative data such as adjacent segment levels, operative time, blood loss, laterality of approach, open versus percutaneous pedicle screw instrumentation and need for primary decompression. Radiographic measurements including segmental and global lumbar lordosis, pelvic incidence, pelvic tilt, sacral slope and sagittal vertical axis were recorded both pre- and immediately post-operatively., Results: Twenty-four patients met criteria for inclusion. Average age was 60.4 ± 10.4 years and average BMI was 31.6 ± 5.0 kg/m 2 . Total operative time was 204.7 ± 83.3 min with blood loss of 187.9 ± 211 mL. Twenty-one patients had pedicle screw instrumentation exchanged percutaneously and 3 patients had open pedicle screw exchange. Two patients suffered pulmonary embolism that was treated medically with no long-term sequelae. One patient had transient lumbar radicular pain and all patients were discharged home with an average length of stay of 3.0 days (range 1-6). Radiographically, global lumbar lordosis improved by an average of 10.3 ± 9.0 degrees, segmental lordosis by 10.1 ± 13.3 degrees and sagittal vertical axis by 3.2 ± 3.2 cm., Conclusion: Single-position prone transpsoas lumbar interbody fusion is a clinically reproducible minimally invasive technique that can effectively treat lumbar adjacent segment disease., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

In recent years, physicians and institutions have come to recognize the increasing opioid epidemic in the United States, thus prompting a dramatic shift in opioid prescribing patterns. The lack of well-studied alternative treatment regimens has led to a substantial burden of opioid addiction in the United States. These forces have led to a huge economic burden on the country. The spine surgery population is particularly high risk for uncontrolled perioperative pain, because most patients experience chronic pain preoperatively and many patients continue to experience pain postoperatively. Overall, there is a large incentive to better understand comprehensive multimodal pain management regimens, particularly in the spine surgery patient population. The goal of this review is to explore trends in pain symptoms in spine surgery patients, overview the best practices in pain medications and management, and provide a concise multimodal and behavioral treatment algorithm for pain management, which has since been adopted by a high-volume tertiary academic medical center., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Objective: Minimally invasive surgery (MIS) for adult spinal deformity (ASD) can offer deformity correction with less tissue manipulation and damage. However, the impact of obesity on clinical outcomes and radiographic correction following MIS for ASD is poorly understood. The goal of this study was to determine the role, if any, that obesity has on radiographic correction and health-related quality-of-life measures in MIS for ASD., Methods: Data were collected from a multicenter database of MIS for ASD. This was a retrospective review of a prospectively collected database. Patient inclusion criteria were age ≥ 18 years and coronal Cobb angle ≥ 20°, pelvic incidence-lumbar lordosis mismatch ≥ 10°, or sagittal vertical axis (SVA) > 5 cm. A group of patients with body mass index (BMI) < 30 kg/m2 was the control cohort; BMI ≥ 30 kg/m2 was used to define obesity. Obesity cohorts were categorized into BMI 30-34.99 and BMI ≥ 35. All patients had at least 1 year of follow-up. Preoperative and postoperative health-related quality-of-life measures and radiographic parameters, as well as complications, were compared via statistical analysis., Results: A total of 106 patients were available for analysis (69 control, 17 in the BMI 30-34.99 group, and 20 in the BMI ≥ 35 group). The average BMI was 25.24 kg/m2 for the control group versus 32.46 kg/m2 (p < 0.001) and 39.5 kg/m2 (p < 0.001) for the obese groups. Preoperatively, the BMI 30-34.99 group had significantly more prior spine surgery (70.6% vs 42%, p = 0.04) and worse preoperative numeric rating scale leg scores (7.71 vs 5.08, p = 0.001). Postoperatively, the BMI 30-34.99 cohort had worse Oswestry Disability Index scores (33.86 vs 23.55, p = 0.028), greater improvement in numeric rating scale leg scores (-4.88 vs -2.71, p = 0.012), and worse SVA (51.34 vs 26.98, p = 0.042) at 1 year postoperatively. Preoperatively, the BMI ≥ 35 cohort had significantly worse frailty (4.5 vs 3.27, p = 0.001), Oswestry Disability Index scores (52.9 vs 44.83, p = 0.017), and T1 pelvic angle (26.82 vs 20.71, p = 0.038). Postoperatively, after controlling for differences in frailty, the BMI ≥ 35 cohort had significantly less improvement in their Scoliosis Research Society-22 outcomes questionnaire scores (0.603 vs 1.05, p = 0.025), higher SVA (64.71 vs 25.33, p = 0.015) and T1 pelvic angle (22.76 vs 15.48, p = 0.029), and less change in maximum Cobb angle (-3.93 vs -10.71, p = 0.034) at 1 year. The BMI 30-34.99 cohort had significantly more infections (11.8% vs 0%, p = 0.004). The BMI ≥ 35 cohort had significantly more implant complications (30% vs 11.8%, p = 0.014) and revision surgery within 90 days (5% vs 1.4%, p = 0.034)., Conclusions: Obese patients who undergo MIS for ASD have less correction of their deformity, worse quality-of-life outcomes, more implant complications and infections, and an increased rate of revision surgery compared with their nonobese counterparts, although both groups benefit from surgery. Appropriate counseling should be provided to obese patients.

Background: There has been an increased interest in lumbar interbody fusions through Kambin's triangle. In this study, we describe percutaneous access to the lumbar disc and insertion of an expandable titanium cage through Kambin's triangle without facetectomy. The objective of this study is to determine the feasibility as well as clinical and radiographical outcomes of completely percutaneous lumbar interbody fusion (percLIF) using an expandable titanium cage through Kambin's triangle., Methods: A retrospective review of patients undergoing single-level percLIF for grade 1 lumbar spondylolisthesis via Kambin's triangle using an expandable titanium cage was performed. Demographic information, Oswestry Disability Index (ODI), preoperative and postoperative radiographic factors, perioperative data, and complications were recorded. Fusion was assessed with 1-year postoperative computed tomography scan or lumbar spine x-ray and defined as bridging disc or posterolateral fusion without evidence of hardware fracture or perihardware lucency., Results: A total of 16 patients (3 males) were included in this study. Spondylolisthesis, anterior disc height, and posterior disc height were significantly improved at 6 weeks, 6 months, and 12 months, postoperatively ( P < 0.05). ODI was significantly improved by 24.4% at 12 months postoperatively ( P = 0.0036). One patient was readmitted within 30 days for pain control but otherwise there were no complications including permanent neurological injury, infection, deep vein thrombosis, pulmonary embolism, or cardiac events. Fifteen (93.8%) patients had radiographic fusion at their 1-year postoperative imaging., Conclusion: Our initial experiences have shown that percLIF can be performed using an expandable titanium cage through Kambin's triangle with excellent radiographic and clinical results. In this series, percLIF is a safe and clinically efficacious procedure for reducing grade 1 lumbar spondylolisthesis and improving radiculopathy. This procedure is completed percutaneously without the use of an endoscope., Clinical Relevance: This study highlights improvements in outcomes of minimally invasive surgery., Level of Evidence: IV., Competing Interests: Declaration of Conflicting Interests: Vikram A. Mehta, MD, MPH: none, Timothy Y. Wang, MD: none, Eric W. Sankey, MD: none, Alexia Bwensa BA: none, Mostafa Gabr, MD: none, C. Rory Goodwin, MD, PhD: Received grants from the Burroughs Wellcome Fund, North Carolina Spine Society, and the NIH/NINDS K12 NRCDP Physician Scientist Award, Robert Wood Johnson Harold Amos Medical Faculty Development Program. Isaac O. Karikari, MD: Consultant for Nuvasive; Receives Fellowship funding from Nuvasive. Member of Advisory Board for Johnson&Johnson Adult Deformity Group. John H. Chi, MD, MPH: Consulting for K2M, Muhammad M. Abd-El-Barr, MD, PhD: Consultant for Spineology, (This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery. Copyright © 2021 ISASS. To see more or order reprints or permissions, see http://ijssurgery.com.)

Background: Robotic-assisted surgery is becoming more widely applied in surgical subspecialties due to its intraoperative and postoperative advantages such as minimally invasive approach, reduced blood loss, shorter hospital stay, and decreased incidence of postoperative complications. However, robotic devices were only recently introduced in the field of spinal surgery. Specifically, percutaneous approaches involving computer-assisted image guidance are relatively new in iliac screw fixation. Previous methods focused on the use of S2-alar-iliac (S2AI) screw fixation which allows for pelvic fixation without a need for side connectors. However, for patients with destructive lesions of the sacrum, placement of these S2AI screws may not be feasible. The purpose of this technical note is to illustrate the implementation of robotic-assisted percutaneous iliac screw fixation in two cases which allows for minimally invasive attachment to the proximal lumbar screws without a side connector and eliminates a potential source of instrumentation failure., Methods: Robotic-assisted percutaneous iliac screw fixation was performed on two patients. The robotics system was used to merge the fluoroscopic images with intraoperative computed tomography (CT) images to plan the trajectories for placement of bilateral pedicle and iliac screws. Intraoperative CT scan was again performed to confirm proper placement of all screws. Rods were then engaged bilaterally with the pedicle and iliac screws without the use of side connectors., Results: The patients did not experience immediate postoperative complications and had stable hardware at one-month follow-up. Our cases demonstrate the surgical efficiency of robotic-assisted lumbo-iliac instrumentation which obviates the need to use a side connector, which is commonly used in iliac fixation. This eliminates a step, which can reduce the possibility of instrumentation failure., Conclusion: Robotic-assisted percutaneous iliac screw fixation is a safe and feasible technique to improve operative and clinical outcomes in complex spinal instrumentation surgeries., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Primary spine tumors are rare neoplasms that affect about 0.62 per 100,000 individuals in the US. Intramedullary spinal cord tumors (IMSCTs) are the rarest of all primary tumors involving the spine and can cause pain, imbalance, urinary dysfunction and neurological deficits. These types of tumors oftentimes necessitate surgical treatment, yet there is a lack of data on hospital length of stay and complication rates following treatment. Given that treatment candidacy, quality of life, and outcomes are tied so closely to potential for prolonged length of stay and postoperative complications, it is important to better understand the factors that increase the risk of these outcomes in patients with IMSCTs., Methods: The National Surgical Quality Improvement Program (NSQIP) database was queried for all patients undergoing surgery for treatment of intramedullary spinal cord tumors between 2005 and 2017. Univariate and multivariate analysis were performed to assess patient risk factors influencing prolonged length of stay and post-op complications., Results: A total of 638 patients were included in the analysis. Pre-operative American Society of Anesthesiology (ASA) physical status classification of 3 and above (OR 1.89; p = 0.0005), dependent functional status (OR 2.76; p = 0.0035) and transfer from facilities other than home (OR 8.12; p <0.0001) were independent predictors of prolonged length of stay (>5 days). The most commonly reported complications were pneumonia (5.7%), urinary tract infection (9.4%), septic shock (3.8%), superficial incisional infection (5.7%), organ or space infection (5.7%), pulmonary embolism (11.3%), DVT requiring therapy (15.1%) and wound dehiscence (5.7%)., Conclusion: Our study demonstrated the significant influence of clinical variables on prolonged hospitalization of IMSCT patients. This should be factored into clinical and surgical decision making and when counseling patients of their expected outcomes., Competing Interests: Disclosures Disclosures unrelated to the current work include Romaric Waguia, Msc received funding support from the American Society of Clinical Oncoly (ASCO) Medical Student Rotation. Meghan Price, BS and Tara Dalton, Msc Received funding support from the Neurosurgery Research & Education Foundation (NREF) summer medical student fellowship. C. Rory Goodwin, MD, PhD: Received grants from the Robert Wood Johnson Harold Amos Medical Faculty Development Program, Burroughs Wellcome Fund, North Carolina Spine Society, and the NIH/NINDS K12 NRCDP Physician-Scientist Award. Daniel Sciubba, MD: Consulting Fee-Baxter International, Inc, Consulting Fee-DePuySynthes, Consulting Fee-Medtronic, Inc., Consulting Fee-Stryker. Isaac O. Karikari: consultant for NuVasive, consultant for Johnson and Johnson. Muhammad M. Abd-El-Barr, MD: consultant for spineology. No other authors have any financial disclosures, (Copyright © 2021. Published by Elsevier Ltd.)

Background: Minimally invasive surgical techniques have resulted in improved patient outcomes. One drawback has been the increased reliance on fluoroscopy and subsequent exposure to ionizing radiation. We have previously shown the efficacy of a novel instrument tracking system in cadaveric and preliminary clinical studies for commonplace orthopedic and spine procedures. In the present study, we examined the radiation and operative time using a novel instrument tracking system compared with standard C-arm fluoroscopy for patients undergoing minimally invasive lumbar fusion., Methods: The radiation emitted, number of radiographs taken, and time required to complete 2 tasks were recorded between the instrument tracking systems and conventional C-arm fluoroscopy. The studied tasks included placement of the initial dilator through Kambin's triangle during percutaneous lumbar interbody fusion and placement of pedicle screws during both percutaneous lumbar interbody fusion and minimally invasive transforaminal lumbar interbody fusion with or without instrument tracking., Results: A total of 23 patients were included in the analysis encompassing 31 total levels. For the task of placing the initial dilator into Kambin's triangle, an average of 4.21 minutes (2.4 vs. 6.6 minutes; P = 0.002), 15 fluoroscopic images (5.4 vs. 20.5; P = 0.002), and 8.14 mGy (3.3 vs. 11.4; P = 0.011) were saved by instrument tracking. For pedicle screw insertion, an average of 5.69 minutes (3.97 vs. 9.67; P < 0.001), 14 radiographs (6.53 vs. 20.62; P < 0.001), and 7.89 mGy (2.98 vs. 10.87 mGy; P < 0.001) were saved per screw insertion., Conclusions: Instrument tracking, when used for minimally invasive lumbar fusion, leads to significant reductions in radiation and operative time compared with conventional fluoroscopy., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Unruptured intracranial saccular aneurysms occur in 3-5% of the general population. As the use of diagnostic medical imaging has steadily increased over the past few decades with the increased availability of computed tomography (CT) and magnetic resonance imaging (MRI), so has the detection of incidental aneurysms. The management of an unruptured intracranial saccular aneurysm is challenging for both patients and physicians, as the decision to intervene must weigh the risk of rupture and resultant subarachnoid hemorrhage against the risk inherent to the surgical or endovascular procedure. The purpose of this paper is to provide an overview of factors to be considered in the decision to offer treatment for unruptured intracranial aneurysms in adults. In addition, we review aneurysm and patient characteristics that favor surgical clipping over endovascular intervention and vice versa. Finally, the authors propose a novel, simple, and clinically relevant algorithm for observation versus intervention in unruptured intracranial aneurysms based on the PHASES scoring system., (© 2020. Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: Instrument-navigation modalities including CT-guided and robot-assisted methods claim both efficacy and accuracy when applied to spine surgery, yet often increase setup and operating times which can translate to increased costs. To see the impact of different technologies on surgical efficiency, we studied the impact of a single surgeon's experience with a multitude of instrument navigational technologies., Methods: Consecutive patients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) were analyzed. Consecutive cases were done with assistance of a robot (Mazor, Medtronic, Minneapolis, MN), with the assistance of fluoroscopic instrument-tracking (TrackX, North Carolina, USA), or fluoroscopy alone without adjunctive navigation in consecutive blocks of time. The cases done without assistance were used to normalize for number of interbody implants and decompressions performed as well as hardware removal if needed. Age, body mass index (BMI), sex, operative levels, laminectomy, need for hardware removal, and total operative time were recorded., Results: A total of 119 cases (74 conventional, 13 robot-assisted, 32 instrument-tracking) were included in analysis. There were no significant differences in age, sex, or BMI between modalities. Average total operative time for robot-assisted, and instrument-tracking-assisted cases was 175.46 ± 46.86 min 119.63 ± 34.33 min, respectively, for each level (p < 0.05 across each group). After normalization against operative times from similar cases performed with conventional fluoroscopy, robotic-navigation added an average of 42.25 ± 28.35 min while use of instrument-tracking saved an average of 13.88 ± 38.69 min. There was no learning curve seen using robotic navigation, as operative times remained consistently longer than similar cases using conventional fluoroscopy and showed no sign of improvement over time. Cases using instrument-tracking were initially slower but trended downwards through approximately 11 patients, at which point operative times were consistently quicker (R 2 = 0.39). None of the assisted cases were abandoned in favor of standard fluoroscopy or required hardware revision., Conclusion: Enabling technology can have a significant impact on surgical efficiency. Compared to MIS-TLIFs performed with standard fluoroscopy, those done with robotic-assistance consistently negatively impacted operative times while instrument-tracking was associated with a short learning curve and in the majority of cases studied showed improved operative times., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Spinal fusion has undergone significant evolution and improvement over the past 50 yr. Historically, spine fusion was noninstrumented and arthrodesis was based entirely on autograft. Improved understanding of spinal anatomy and materials science ushered in a new era of spinal fusion equipped with screw-based technologies and various interbody devices. Osteobiologics is another important realm of spine fusion, and the evolution of various osteobiologics has perhaps undergone the most change within the past 20 yr. A new element to spinal instrumentation has recently gained traction-namely, surface technology. New data suggest that surface treatments play an increasingly well-recognized role in inducing osteogenesis and successful fusion. Until now, however, there has yet to be a unified resource summarizing the existing data and a lack of consensus exists on superior technology. Here, authors provide an in-depth review on surface technology and its impact on spinal arthrodesis., (© Congress of Neurological Surgeons 2021.)

Objective: The rate of symptomatic adjacent-segment disease (ASD) after newer minimally invasive techniques, such as lateral lumbar interbody fusion (LLIF), is not known. This study aimed to assess the incidence of surgically significant ASD in adult patients who have undergone index LLIF and to identify any predictive factors., Methods: Patients who underwent index LLIF with or without additional posterior pedicle screw fixation between 2010 and 2012 and received a minimum of 2 years of postoperative follow-up were retrospectively included. Demographic and perioperative data were recorded, as well as radiographic data and immediate perioperative complications. The primary endpoint was revision surgery at the level above or below the previous construct, from which a survivorship model of patients with surgically significant symptomatic ASD was created., Results: Sixty-seven patients with a total of 163 interbody levels were included in this analysis. In total, 17 (25.4%) patients developed surgically significant ASD and required additional surgery, with a mean ± SD time to revision of 3.59 ± 2.55 years. The mean annual rate of surgically significant ASD was 3.49% over 7.27 years, which was the average follow-up. One-third of patients developed significant disease within 2 years of index surgery, and 1 patient required surgery at the adjacent level within 1 year. Constructs spanning 3 or fewer interbody levels were significantly associated with increased risk of surgically significant ASD; however, instrument termination at the thoracolumbar junction did not increase this risk. Surgically significant ASD was not impacted by preoperative disc height, foraminal area at the adjacent levels, or changes in global or segmental lumbar lordosis., Conclusions: The risk of surgically significant ASD after LLIF was similar to the previously reported rates of other minimally invasive spine procedures. Patients with shorter constructs had higher rates of subsequent ASD.

Background Context: Preoperative optimization of medical comorbidities prior to spinal surgery is becoming an increasingly important intervention in decreasing postoperative complications and ensuring a satisfactory postoperative course. The treatment of preoperative anemia is based on guidelines made by the American College of Cardiology (ACC), which recommends packed red blood cell transfusion when hematocrit is less than 21% in patients without cardiovascular disease and 24% in patients with cardiovascular disease. The literature has yet to quantify the risk profile associated with preoperative pRBC transfusion., Purpose: To determine the incidence of complications following preoperative pRBC transfusion in a cohort of patients undergoing spine surgery., Study Design: Retrospective review of a national surgical database., Patient Sample: The national surgical quality improvement program database OUTCOME NEASURES: Postoperative physiologic complications after a preoperative transfusion. Complications were defined as the occurrence of any DVT, PE, stroke, cardiac arrest, myocardial infarction, longer length of stay, need for mechanical ventilation greater than 48 h, surgical site infections, sepsis, urinary tract infections, pneumonia, or higher 30-day mortality., Methods: The national surgical quality improvement program database was queried, and patients were included if they had any type of spine surgery and had a preoperative transfusion., Results: Preoperative pRBC transfusion was found to be protective against complications when the hematocrit was less than 20% and associated with more complications when the hematocrit was higher than 20%. In patients with a hematocrit higher than 20%, pRBC transfusion was associated with longer lengths of stay, and higher rates of ventilator dependency greater than 48 h, pneumonia, and 30-day mortality., Conclusion: This is the first study to identify an inflection point in determining when a preoperative pRBC transfusion may be protective or may contribute to complications. Further studies are needed to be conducted to stratify by the prevalence of cardiovascular disease., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Study Design: Literature review., Objectives: It has been reported that 2.4-3.7% of all blunt trauma victims suffer some element of cervical spine fracture, with the majority of these patients suffering from C3-7 (subaxial) involvement. With the improvement of first-response to trauma in the community, there are an increasing number of patients who survive their initial trauma and thus arrive at the hospital in need of further evaluation, stabilization, and management of these injuries., Methods: A comprehensive literature review compiled all relevant data on the biomechanics, imaging, evaluation, and medical and surgical management strategies for subaxial cervical spine fractures., Results: After review of the current literature on subaxial cervical spine biomechanics, imaging characteristics, evaluation strategies and surgical and orthopedic management techniques, the authors created a comprehensive review and protocol for management of subaxial cervical spine fractures., Conclusions: The subaxial cervical spine is biomechanically and anatomically unique from the remainder of the spinal axis. Evaluation of subaxial cervical spine injuries is nuanced, and improper management of these injuries can lead to significant patient morbidity and even death. This provides a comprehensive review combining anatomy, imaging characteristics, evaluation strategies, and surgical and orthopedic management principles for subaxial cervical spine fractures., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The cerebellum was long perceived to be a region of limited importance with primary functions in the regulation of motor control. A degree of its functional topography in motor modulation has been traditionally appreciated. However, an evolving body of evidence supports its role in a range of cognitive processes, including executive decision making, language, emotional processing, and working memory. To this end, numerous studies of cerebellar stroke syndromes as well as investigations with functional magnetic resonance imaging and diffusion tensor imaging have given clinicians a better model of the functional topography within the cerebellum and the essential lanes of communication with the cerebrum. With this deeper understanding, neurosurgeons should integrate these domains into the perioperative evaluation and postoperative rehabilitation of patients with cerebellar tumors. This review aims to discuss these understandings and identify valuable tools for implementation into clinical practice., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: Stereotactic body radiation therapy (SBRT) offers efficient, noninvasive treatment of spinal neoplasms. Single-fraction (SF) high-dose SBRT has a relatively narrow therapeutic window, while hypofractionated delivery of SBRT may have an improved safety profile with similar efficacy. Because the optimal approach of delivery is unknown, the authors examined whether hypofractionated SBRT improves pain and/or functional outcomes and results in better tumor control compared with SF-SBRT., Methods: This is a single-institution retrospective study of adult patients with spinal metastases treated with SF- or three-fraction (3F) SBRT from 2008 to 2019. Demographics and baseline characteristics, radiographic data, and posttreatment outcomes at a minimum follow-up of 3 months are reported., Results: Of the 156 patients included in the study, 70 (44.9%) underwent SF-SBRT (median total dose 1700 cGy) and 86 (55.1%) underwent 3F-SBRT (median total dose 2100 cGy). At baseline, a higher proportion of patients in the 3F-SBRT group had a worse baseline profile, including severity of pain (p < 0.05), average use of pain medication (p < 0.001), and functional scores (p < 0.05) compared with the SF-SBRT cohort. At the 3-month follow-up, the 3F-SBRT cohort experienced a greater frequency of improvement in pain compared with the SF-SBRT group (p < 0.05). Furthermore, patients treated with 3F-SBRT demonstrated a higher frequency of improved Karnofsky Performance Scale (KPS) scores (p < 0.05) compared with those treated with SF-SBRT, with no significant difference in the frequency of improvement in modified Rankin Scale scores. Local tumor control did not differ significantly between the two cohorts., Conclusions: Patients who received spinal 3F-SBRT more frequently achieved significant pain relief and an increased frequency of improvement in KPS compared with those treated with SF-SBRT. Local tumor control was similar in the two groups. Future work is needed to establish the relationship between fractionation schedule and clinical outcomes.

Spine surgery has been disproportionately impacted by medical liability and malpractice litigation, with the majority of claims and payouts related to procedural error. One common area for the potential avoidance of malpractice claims and subsequent payouts involves misplaced pedicle and/or lateral mass instrumentation. However, the medicolegal impact of misplaced screws on spine surgery has not been directly reported in the literature. The authors of the current study aimed to describe this impact in the United States, as well as to suggest a potential method for mitigating the problem.This retrospective analysis of 68 closed medicolegal cases related to misplaced screws in spine surgery showed that neurosurgeons and orthopedic spine surgeons were equally named as the defendant (n = 32 and 31, respectively), and cases were most commonly due to misplaced lumbar pedicle screws (n = 41, 60.3%). Litigation resulted in average payouts of $1,204,422 ± $753,832 between 1995 and 2019, when adjusted for inflation. The median time to case closure was 56.3 (35.2-67.2) months when ruled in favor of the plaintiff (i.e., patient) compared to 61.5 (51.4-77.2) months for defendant (surgeon) verdicts (p = 0.117).

Split cord malformation (SCM) is a developmental disorder that is usually symptomatic and diagnosed in childhood. The majority of these lesions are in the thoracic and lumbar spine, with only 1%-3% of cases found in the cervical spine. This is a case report of a 55-year-old female patient with an unremarkable medical history who presented with neck pain. Upon workup, she was found to have extensive developmental anomalies throughout her cervical and thoracic spine, including an incidentally found type 2 SCM and multiple autofused vertebrae. There are only 6 similar studies published in the literature. There was extensive facet degeneration in her cervical spine, which was suspected to be the etiology of her neck pain. This case illustrates the rare finding of asymptomatic adult cervical SCM and the likely significance of her autofused vertebrae causing accelerated symptomatic facet spondylosis., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Introduction: As minimally invasive spine surgery gains popularity, a focused effort must be made to reduce intraoperative radiation exposure to levels as low as reasonably achievable. Here, we demonstrate the clinical efficacy of a novel technology to aid in instrument navigation that aims to reduce intraoperative radiation exposure, number of fluoroscopic images, and time required to perform the most radiation intensive portions of a multitude of spinal procedures., Methods: An internally randomized controlled study was performed over a 1-month period in order to clinically evaluate the effect of the C-arm assisted instrument tracking system, TrackX, on surgeon workflow, time, and radiation emitted. Three surgeons performed multiple spinal procedures on a total of 10 study patients and an additional 3 control patients. The surgeries encompassed minimally invasive spinal techniques and spanned extreme lateral interbody fusion, oblique lumbar interbody fusion, transforaminal lumbar interbody fusion along with percutaneous iliac screw placement, hardware removal, and kyphoplasty. The tasks studied included skin marking, first dilator insertion, localization for hardware placement and hardware removal., Results: Overall radiation reduction was 83% ( P < .0001). Overall reduction in x-rays taken was 78% ( P < .0001). Overall time reduction was 81% ( P = .0003). Statistical significance held for each surgeon studied and for nearly every procedure type. In these 10 study procedures, over 2 hours of overall operating room time was saved, all while requiring negligible set up time and no system calibration or supplementary x-rays to be taken. There were no adverse outcomes for any study patient, and there was no case where TrackX was not able to successfully complete a given portion of a procedure., Conclusions: TrackX instrument navigation is a clinically efficacious and accurate instrument tracking modality. This is the first instrument navigational technology that reduces radiation exposure and images required to complete a procedure while decreasing operative time. TrackX thus allows increased surgical efficiency while increasing operative efficiency and improving intraoperative safety., Level of Evidence: 2., Competing Interests: Disclosures and COI: The authors, with the exception of Farah Hamouda, report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper. Ms Hamouda is a research scientist at TrackX and helped to collect and analyze the data. Ms Hamouda receives salary payment from a company involved in the manufacture of a device examined in this study. This author's role was instrumental in supplying the equipment used in this article, and her experience with the technical aspects of the imaging system were necessary to conduct this study., (©International Society for the Advancement of Spine Surgery 2020.)

The decision to restart systemic anticoagulation after surgery requires a nuanced risk-benefit analysis. The potential for surgical site bleeding must be balanced against the risk of thromboembolic events. In the context of postoperative neurosurgical patients, the consequences of either hemorrhage or thromboembolism can be devastating. However, few studies to date have attempted to determine the optimal time to resume anticoagulation after craniotomy. As a result, the decision of when to restart anticoagulation remains largely subjective and highly variable between surgeons and institutions. In this study, we aim to develop an algorithm that incorporates existing metrics and expert opinion toward the goal of developing guidelines for restarting anticoagulation after elective craniotomy., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: More than 120,000 anterior cervical discectomy and fusions (ACDFs) are performed annually. Pseudarthrosis is a potential delayed adverse event that affects up to 33% of patients. The degree to which this adverse event affects both patient quality-of-life (QOL) outcomes and health care costs is poorly understood., Methods: Patients who underwent revision surgery for pseudarthrosis between 2007 and 2012 were identified and matched to controls not experiencing pseudarthrosis in a 1:2 fashion (case/control). Cases and controls were compared regarding total health care costs incurred in the year after the index ACDF and QOL outcomes on the following metrics: EuroQol Five-Dimensions Questionnaire, Patient Health Questionnaire-9, and Pain Disability Questionnaire., Results: Of 738 patients who underwent ACDF, 11 underwent surgery for pseudarthrosis. No differences were noted between cases and controls regarding any of the matched variables. Patients in the pseudarthrosis cohort had poorer postoperative scores on the EuroQol Five-Dimensions Questionnaire mobility, usual activities, pain/discomfort, and quality-adjusted life-year dimensions. In addition, 64% of patients with pseudarthrosis had worsened quality-adjusted life-year scores compared with only 9% of controls (P < 0.01). Patients with pseudarthrosis also had poorer mental health (P < 0.01) and pain disability outcomes (P < 0.01) than did controls. Pseudarthrosis was associated with significant increases in direct costs, direct postoperative costs, and total costs (all P < 0.01)., Conclusions: This is the first study to characterize the effect of surgical revision for pseudarthrosis on both QOL outcomes and care costs after ACDF. Patients requiring revision experienced significantly poorer QOL outcomes and higher care costs relative to controls., (Copyright © 2019 Elsevier Inc. All rights reserved.)

OBJECTIVE. Compared with open procedures, minimally invasive surgical procedures are associated with increased radiation exposure and long-term health risks. Ultralow radiation imaging coupled with image enhancement and instrument tracking (ULRI-IE/IT) is a new image modifier that allows a computer to show real-time movement of an instrument as it is adjusted, mimicking live fluoroscopy but without continuous radiation production. The purpose of this study was to determine the accuracy and radiation output of ULRI-IE/IT compared with unassisted conventional fluoroscopy in a variety of surgical procedures. MATERIALS AND METHODS. Physicians of various specialties were asked to identify the ideal location for instrumentation in various spinal, orthopedic, pain, and physiatric procedures and then place an instrument in this location in a cadaver both with and without ULRI-IE/IT assistance. Whether ULRI-IE/IT was used was randomly assigned to reduce the impact of learning. Radiation exposure, time to place the instrument, and the number of images required to achieve accurate positioning were recorded for each procedure. These were compared for unassisted and ULRI-IE/IT-assisted fluoroscopy to determine the utility of ULRI-IE/IT in minimally invasive instrumentation. RESULTS. Twenty-three trials of nine procedures by five physicians were completed both with and without assistance of ULRI-IE/IT. The procedures ranged from percutaneous pedicle screw insertion to foramen ovale ablation. Total time to localize the instrument for all 23 cases was 31.2% longer without assistance. Use of ULRI-IE/IT reduced the total number of images per case by 74.8% and radiation exposure by 91.8%. With ULRI-IE/IT, physicians were able to successfully place the instrument in the correct location on the first attempt in 82.6% of trials and in the second attempt in all trials versus a mean of 4.65 images needed for unassisted fluoroscopy. CONCLUSION. Use of ULRI-IE/IT can dramatically reduce radiation output and the number of images acquired and time required to perform fluoroscopic procedures.