< PreviousAbstracts AnnualForum’19 10ANNUAL FORUM ’19 | LAS VEGAS, NEVADA | OCT. 31–NOV. 2, 2019 CONCURRENT SESSION 2A: EMERGING & NAVIGATION FREE PAPERS Results: All the procedures were deemed successful, without device-related tears. Sufficient bone removal was obtained using the device in 96% of the procedures. In some cases of multi- level complicated fusions, the time reduction using the device was estimated at several hours. Lumbar foraminotomy using the device required, on average, 2 minutes/foramen. Osteophyte removal required, on average, 3.2 minutes. The device was successfully used in both open and minimal invasive settings. Conclusions: The results of the study found that the device is safe and effective for performing osteophyte removal and foraminotomy in both open and minimal invasive settings. Procedure time reduction was noted as the most significant advantage by the surgeons. Disclosures: J. Peloza: None. L. Khoo: B; Carevature Medical Ltd. M. Millgram: B; Carevature Medical Ltd. S. Kutz: B; Carevature Medical Ltd. R. Guyer: B; Carevature Medical Ltd. E. Ashkenazi: B; Carevature Medical Ltd.. D; Carevature Medical Ltd. Paper #4 Stem Cell Injections for Axial Back Pain: A Systematic Review of Associated Risks and Complications with Case Illustration of Diffuse Hyperplastic Gliosis Resulting in Cauda Equina Syndrome Salah Aoun, MD; Valery Peinado Reyes, PA; Tarek El Ahmadieh, MD; and Carlos Bagley, MD Introduction: Axial lower back pain is a disease of epidemic proportions that exerts a heavy global toll on the active workforce, and results in more than half a trillion dollars in annual costs. Stem cell injections are being increasingly advertised as a restorative solution for various degenerative diseases and are becoming more affordable and attainable by the public. Aims/Objectives: There have been multiple reports in the media of these injections being easily available abroad outside of clinical trials, but scientific evidence supporting them remains scarce. We present the case of a serious complication after a stem cell injection for back pain and provide a systematic review of the literature of their efficacy and associated risks and complications. Methods: We performed a systematic review of the literature using the PubMed, Google Scholar, and Scopus online electronic databases for articles reporting stem cell injections for axial back pain in accordance with the PRISMA guidelines. Primary focus was on outcomes and complications. We also report a case of glial hyperplasia of the roots of the cauda equina directly related to stem cell injections performed abroad. Results: We identified 14 studies with 147 patients that met our search criteria. Follow-up periods ranged from 6 months to 6 years, and 50% of the studies had a follow-up of 1 year or less. Most studies reported favorable outcomes although 33% were using subjective measures. There was a tendency for pain relief to wane after 6 months to 2 years, with patients seeking a surgical solution. Only one study was a randomized controlled trial. Conclusions: There is still insufficient data to support stem cell injections for back pain. Additional randomized controlled trials with long term follow-up are necessary before statements regarding their efficacy and safety can be made. Disclosures: S. Aoun: None. V. Peinado Reyes: None. T. El Ahmadieh: None. C. Bagley: None. Paper #5: Minimally Invasive TLIF with Expandable Articulating Interbody Spacers Significantly Improves Radiographic Outcomes Compared to Static Interbody Spacers Anthony Russo, MD 1 ; Steven Schopler, MD 2 ; Katelyn Stetzner, FNP-C 1 ; Samantha Greeley, BS 3 ; Torrey Shirk, BA 3 ; and Charles Ledonio, MD, CCRP 3 Montana Orthopedics, Butte, MT 1 ; Southern California Orthopedic Institute, Bakersfield, CA 2 ; and Globus Medical, Inc., Audubon, PA 3 Introduction: The goal of minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) is to restore and maintain disc height and lordosis until arthrodesis occurs while minimizing muscle disruption and improving recovery time. The radiographic outcomes of an articulating expandable spacer in MIS TLIFs have yet to be thoroughly investigated in comparison to more traditionally used static spacers. Aims/Objectives: The purpose of this study is to compare the radiographic outcomes of an articulating expandable spacer to a static spacer used in MIS-TLIF. Methods: This was a multi-site, multi-surgeon, retrospective clinical study from a prospectively collected database with Institutional Review Board exemption. It included 48 patients with a diagnosis of degenerative disc disease at one level from L3 to S1 with or without Grade 1 spondylolisthesis who underwent MIS TLIF using either an articulating expandable or static interbody spacer for the treatment of low back pain and/ or radiculopathy. Twenty-seven patients were in the articulating Abstracts AnnualForum’19 11ANNUAL FORUM ’19 | LAS VEGAS, NEVADA | OCT. 31–NOV. 2, 2019 CONCURRENT SESSION 2A: EMERGING & NAVIGATION FREE PAPERS expandable interbody spacer group, while 21 patients were in the static interbody spacer group. Radiographic records were assessed for disc height, neuroforaminal height and lordosis at baseline, 3 months, 6 months, and final follow-up. Results: The articulating expandable spacer group displayed significantly greater improvement in anterior disc height, posterior disc height, and neuroforaminal height from baseline compared to the static spacer group. Increases in intervertebral angle from baseline were significantly greater in the expandable group than the static group at 3 months, 6 months, and final follow-up by averages of 2.5°, 2.8°, and 3.1°, respectively (p<0.05). The articulating expandable spacer group resulted in a significantly greater improvement in lumbar lordosis from baseline to 3 months and 6 months than the static spacer group by 4.4° and 4.0°, respectively (p<0.05). Conclusions: MIS TLIF with articulating expandable interbody spacers provides significant restoration and maintenance of disc height, neuroforaminal height, and lordosis compared to static spacers in this comparative cohort. Long-term clinical outcomes are needed to correlate with these radiographic improvements. Disclosures: A. Russo: A; Globus Medical, Orthofix. B; Globus Medical, Orthofix, SurGenTec. F; Globus Medical. S. Schopler: A; Globus Medical. B; Organogenesis, Arthrex. F; RTI Surgical. K. Stetzner: None. S. Greeley: E; Globus Medical. T. Shirk: E; Globus Medical. C. Ledonio: E; Globus Medical. Paper #6: Comparative Effectiveness of Minimally Invasive Bilateral Transforaminal Lumbar Interbody Fusions Using 2 Intervertebral Titanium Expandable Versus Peek Static Interbody Spacers: 1-year Radiographic Outcomes Steven Schopler, MD 1 ; Nickul Jain, MD 1 ; Emily Fish, PA-C 1 ; Jessica Riggleman, BS 2 ; Samantha Greeley, BS 2 ; and Charles Ledonio, MD, CCRP 2 Southern California Orthopedic Institute, Bakersfield, CA 1 and Globus Medical, Inc., Audubon, PA 2 Introduction: Transforaminal lumbar interbody fusion (TLIF) using static spacers is a recognized procedure for the treatment of degenerative disc disease (DDD) with or without spondylolisthesis, which is commonly performed either as an open or minimally invasive procedure. The advantage of minimally invasive surgery (MIS) has been reported to have less blood loss, minimal tissue disruption, and earlier recovery time. MIS bilateral TLIF with 2 interbody spacers has been developed to improve restoration of sagittal alignment, which is essential for better patient outcomes. As with any new technique, clinical outcome studies are essential to determine its efficacy. Aims/Objectives: This study compares the radiographic outcomes of patients who underwent bilateral TLIF with 2 intervertebral interbody expandable or 2 static spacers. Methods: This is a single-surgeon, retrospective, Institutional Review Board-exempt chart review of 73 consecutive patients with DDD who underwent single-level bilateral MIS-TLIF using either 2 PEEK static (38) or 2 titanium expandable interbody spacers (35) within the same vertebral level. Mean differences of radiographic outcomes were compared from preoperative to postoperative 12-month follow-up. Statistical results were significant when p<0.05. Results: Seventy-three consecutive patients were evaluated with an average age of 56.6±14.5 years; 50.7% (37/73) were female. Of the 73 patients, 31.5% had spacers placed at L4- L5 (23/73) and 64.4% (47/73) at L5-S1. Mean improvement of anterior disc height from preoperative to 12 months was higher in the expandable group [93.2% (6.1±5.3mm)] than in the static group [54.7% (4.0±2.7mm)] (p>0.05). For posterior disc height, mean improvement from preoperative to 12 months was significantly higher in the expandable group [234.8% (7.4±2.6)] than in the static group [77.7% (3.7±2.6)] (p<0.05). There was no significant difference in lumbar lordosis between the two groups (p>0.05). Conclusions: This study showed significant positive radiographic outcomes for patients who underwent MIS bilateral TLIF using 2 intervertebral titanium expandable interbody spacers based on significant changes in disc height compared to PEEK static interbody spacers; with the results sustained up to 12-month follow-up. Further studies with larger sample sizes and longer follow-up are needed to determine the durability of this new procedure. Disclosures: S. Schopler: A; Globus Medical. B; Organogenesis, Arthrex. F; RTI Surgical. N. Jain: A; Globus Medical. B; Spineart. E. Fish: None. J. Riggleman: D; Globus Medical. E; Globus Medical. S. Greeley: D; Globus Medical. E; Globus Medical. C. Ledonio: E; Globus Medical.Abstracts AnnualForum’19 12ANNUAL FORUM ’19 | LAS VEGAS, NEVADA | OCT. 31–NOV. 2, 2019 CONCURRENT SESSION 2A: EMERGING & NAVIGATION FREE PAPERS Paper #7: Implementation of Enhanced Recovery After Surgery (ERAS) Program for Patients Undergoing Same Day Outpatient Elective Minimally Invasive Transforaminal Lumbar Interbody Fusion (MIS TLIF) Samuel Joseph, MD 1 ; Uhuru Smith, MD 2 ; and Ashley Urso, BS 3 Joseph Spine Institute, Tampa, FL 1; Sweet Dreams Anesthesia, Tampa, FL 2 ; and University of South Florida, Tampa, FL 3 Introduction: Enhanced recovery after surgery (ERAS) programs for improving spinal fusion surgery are possible and necessary. To date no programs have been described for minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) to allow for same day discharge in a safe and effective manner. Aims/Objectives: In this report, the authors review the development of an outpatient ERAS program for MI TLIF, with a focus on multimodal analgesia combined with pre-induction spinal anesthesia and local infiltration prior to emergence. Methods: A prospective review of the first 30 consecutive patients in which the ERAS program was implemented for elective 1 and 2-level MIS TLIF with bilateral pedicle screw instrumentation. A synergistic protocol including multimodal preoperative analgesics, intrathecal anesthesia, combined general and local anesthesia, and postoperative medication was implemented. Data collection was performed by review of medical records. Data included number of levels fused, age, operative time, Body Mass Index (BMI), ASA Physical Status Classification, time to discharge, visual analog pain (VAS) level at discharge, readmission rate, after hours calls to office, wound complications, postoperative narcotic use till first postoperative visit, and rates of postoperative urinary retention. Results: A total of 20 1-level and 10 2-level MI TLIFs were performed. Patients consisted of 17 females and 13 males. Mean age was 49 years (range, 34-64), mean BMI was 33 (range, 26- 44), mean ASA was 2 (range, 1-3), mean operative time was 109 minutes (range, 44-227), mean time to discharge was 161 minutes (range, 65-321), mean VAS was 4.5 (range, 1-10). There was no premature refill of narcotic, no readmission, no premature return or call to office due to pain, no postoperative urinary retention, and no wound complications at latest follow-up. Conclusions: Inadequate pain control after surgery has been shown to prolong rehabilitation and opioid use, increase morbidity, impair quality of life, and increase health care costs. We employed the use of multimodal analgesia to achieve adequate pain control while decreasing the use of opioids and their potential for respiratory depression and postoperative operative cognitive dysfunction. This report describes the first ERAS protocol for MIS TLIF. Pre-, intra-, and postoperative interventions were associated with no complications and no readmissions. Disclosures: S. Joseph: B; Osseus, Arthrex, Alphatec Spine, MiRus. D; Osseus, MiRus. F; Osseus, Alphatec Spine. U. Smith: None. A. Urso: None. Paper #8: Virtual/Mixed Reality Technologies for Minimally Invasive and Complicated Spinal Surgery Norihiro Isogai 1 ; Haruki Funao 1 ; Maki Sugimoto 2 ; Wataru Narita 3 ; Aeru Hayashi 4 ; Yutaka Sasao 1 ; Makoto Nishiyama 1 ; Keijyu Aokage 5 ; Masahiro Tsuboi 5 ; and Ken Ishii 1 International University of Health and Welfare, Tokyo, Japan 1 ; The University of Tokyo, Tokyo, Japan 2 ; Kameoka City Hospital, Kameoka, Japan 3 ; International University of Health and Welfare Mita Hospital, Tokyo, Japan 4 ; National Cancer Center Hospital East, Tokyo, Japan 5 Introduction: Although intraoperative fluoroscopy and computed tomography (CT)-based navigation are useful in spinal surgery, the drawbacks of fluoroscopy are radiation exposure and limitation of two-dimensional images for a three-dimensional (3D) configuration, and CT-based navigation systems are not universally available due to costs. Virtual reality (VR) is computer- generated scenario that simulates a realistic experience. Mixed reality (MR) is another terminology, merging of real and virtual worlds to produce new environments and visualizations in real time. MR can be applied for image overlay technique, in which we can utilize true 3D viewing in spine surgery. Aims/Objectives: To describe a new technology which combines VR and MR "image overlay technique," in which dynamic 3D images were superimposed on the patient's actual body surface, as a reference for minimally invasive and complicated spinal surgeries. Methods: Three patients with degenerative spondylolisthesis, degenerative lumbar scoliosis, and lung cancer metastasis to the thoracic spine were included in this study. Two-level lateral lumbar interbody fusion, circumferential spinal fusion from Th10 to the pelvis, and total en block spondylectomy combined with right upper lobectomy were performed. Raw data obtained from CTs were reconstructed to volume rendering as polygon data. A Mac and DICOM workstation OsiriX was used for image analysis. OsiriX was set to reproduce the patient body surface, and the positional coordinates of the pelvis or rib cage were fixed as physiological markers on the body surface. Results: The surgeons and surgical team could plan surgical strategies based on VR/MR images simulating minimally Abstracts AnnualForum’19 13ANNUAL FORUM ’19 | LAS VEGAS, NEVADA | OCT. 31–NOV. 2, 2019 invasive and complicated surgical procedures preoperatively. Intraoperative image overlay technique was helpful for anatomical identification of surgical targets, and for 3D trajectories of both cage and screw insertion. Unexpected nerve, vessel, and organ injuries could be avoided in all procedures. Postoperative radiographs and CT images showed accurate instrumentation placements. Conclusions: Although VR/MR technologies for spine surgery is still in research and development phase, preoperative planning and intraoperative image overlay technique were useful for both minimally invasive and complicated spine surgeries. These technologies could be used safely to provide more information, especially for hidden structures and unusual anatomy. Disclosures: N. Isogai: None. H. Funao: None. M. Sugimoto: None. W. Narita: None. A. Hayashi: None. Y. Sasao: None. M. Nishiyama: None. K. Aokage: None. M. Tsuboi: None. K. Ishii: None. Paper #9: Navigated Robotic Assistance Improves Pedicle Screw Accuracy In Minimally Invasive Surgery of the Lumbosacral Spine: 600 Pedicle Screws in a Single Institution David Wallace, MD 1 ; Arnold Vardiman, MD 1 ; Grant Booher, MD 1 ; Neil Crawford, PhD 2 ; Jessica Riggleman, BS 2 ; Samantha Greeley, BS 2 ; and Charles Ledonio, MD, CCRP 2 University of Texas Health San Antonio, San Antonio, TX 1 and Globus Medical, Inc., Audubon, PA 2 Introduction: In the emerging field of robot-assisted spine surgery, radiographic evaluation of pedicle screw accuracy in the surgical setting is of high interest. Advances in medical imaging have improved the accuracy of pedicle screw placement, from fluoroscopic-guided to computer-aided navigation. Aims/Objectives: This study describes pedicle screw accuracy of the first 106 consecutive cases in which navigated robotic assistance was used in a private practice clinical setting. Methods: A retrospective, Institutional Review Board-exempt review of the first 106 navigated robot-assisted spine surgery cases was performed. Radiographic evaluation of screw tip and screw tail offset distance and angulation from preoperative plan to actual final placement based on intraoperative computerized tomography (CT) images was calculated. Additionally, pedicle screw malposition, reposition, and return to operating room (OR) rates were collected. A CT-based Gertzbein and Robbins System (GRS) was used to classify pedicle screw accuracy. Screws with an A or B grade were deemed as accurate while screws with a C, D, or E grade were considered inaccurate. The number of accurate screws divided by the number of total screws placed with robotic navigation resulted in an accuracy percentage for the first 106 cases. Results: In the first 106 cases, 630 lumbosacral pedicle screws were placed. Thirty screws (5 patients) were placed without the robot due to surgeon discretion. Of the 600 pedicle screws inserted by navigated robotic guidance, only 1.5% (9/600) were repositioned intraoperatively. The average age of patients was 64.8 years, and 55% were female. The average body mass index of the patients was 31 kg/m2. The majority of the surgery diagnoses were degenerative disc disease (79) and adjacent segment disease (19). The average offset from preoperative plan to actual final placement was 1.7±1.3 mm from the tip, 1.8±1.2 mm from the tail, and 2.0±1.6 degrees of angulation. Based on the GRS CT-based grading, 98.2% (589/600) screws were graded A or B, 1.5% (9/600) screws were graded C, and 0.3% (2/600) screws were graded D. Two complications, interbody removal and wound vacuum-assisted closure, were reported as requiring a return to the OR, but these were not related to robotic guidance or pedicle screws. Conclusions: This study demonstrated a high level of accuracy (98.2%) in the clinical use of navigated, robot-assisted surgery in the first 106 robotic cases, with only 2 non-screw-related complications requiring return to the OR. Disclosures: D. Wallace: None. A. Vardiman: A; Globus Medical. C; Medtronic, Abbott. F; Globus Medical. G. Booher: None. N. Crawford: E; Globus Medical. F; Globus Medical. J. Riggleman: E; Globus Medical. S. Greeley: E; Globus Medical. C. Ledonio: E; Globus Medical. Paper #10: Combining Technologies— Robotic-Assisted Endoscopic Transforaminal Lumbar Interbody Fusion Jason Liounakos, MD and Michael Wang, MD University of Miami, Miami, FL Introduction: The overarching goal of robotic surgery is to improve outcomes by facilitating minimally invasive procedures, improving manual dexterity, and standardizing workflow. While many surgical fields have embraced robotics, spine surgery has not yet seen a global adoption. This likely owes to the innate complexities and multiple exquisitely distinct steps involved in each operation. Whereas master-slave systems are ideally suited for general surgery, this is not the case for spine surgery, where semi-active robotic guidance systems dominate. Such systems have traditionally only been used for the placement of spinal instrumentation. By combining both robotic and CONCURRENT SESSION 2A: EMERGING & NAVIGATION FREE PAPERS Abstracts AnnualForum’19 14ANNUAL FORUM ’19 | LAS VEGAS, NEVADA | OCT. 31–NOV. 2, 2019 endoscopic technologies, we aim to push the boundaries of minimally invasive spine surgery. Aims/Objectives: We describe our initial experience utilizing a next-generation robotic guidance system with navigation (Mazor X Stealth, Medtronic, Minneapolis, MN) for the placement of percutaneous pedicle screws, as well as the novel targeting of a disc space for endoscopic discectomy and interbody fusion. Methods: Procedural workflow involves robotic-assisted placement of percutaneous pedicle screws under live navigation. The disc space is then targeted robotically and safety is assessed with triggered electromyography. The endoscope is inserted and discectomy and end-plate preparation proceed, followed by delivery of an expandable interbody device. Demographic and surgical data is being collected for this initial series of patients undergoing robotic- assisted endoscopic transforaminal lumbar interbody fusion (TLIF). Data includes procedure length, robot time, time-per- screw, need for screw revision, blood loss, complications, and length of stay. Results: Five patients with an average age of 67 years (range, 55-72) underwent surgery. One 2-level and 4 1-level lumbar procedures were performed. Mean procedure length and robot time was 135 minutes and 67.6 minutes for 1-level surgeries, respectively. Twenty-two screws were placed percutaneously under robotic guidance with navigation. Appropriate position was confirmed with fluoroscopy, and no screws required revision. Mean time per screw was 359 seconds. Mean blood loss was 100 cc and mean hospital stay was 2 days. There were no complications. Conclusions: Utilizing robotic guidance for disc space access for discectomy and interbody fusion is one way to expand the role of robotics in spine surgery to more than pedicle screw placement. Through the ongoing assessment of where different technologies intersect, we may positively alter their trajectories for advancement. Doing so is necessary to harmoniously blend tools with distinct purposes to obtain the best outcome through improved surgical efficiency and minimal invasiveness. Our early positive preliminary results show that this is possible. Disclosures: J. Liounakos: None. M. Wang: A; Department of Defense. B; Vallum, DePuy Synthes, Stryker K2M, Spineology, Globus Medical. D; Innovative Surgical Devices. E; University of Miami. F; Children’s Hospital of Los Angeles, DePuy Synthes, Springer Publishing, Quality Medical Publishing. Paper #11: Surgical Testing Comparison of Single Position Robot-Assisted Navigation Versus Conventional MIS Bilateral Screw Trajectory During LLIF Procedure: An In-vitro Study Themistocles Protopsaltis, MD 1 ; Jeffery Larson, MD 2 ; Richard Frisch, MD 3 ; Kade Huntsman, MD 4 ; Todd Lansford, MD 5 ; Robert Brady, MD 6 ; Chris Maulucci, MD 7 ; Gerald Hayward II, BS 8 ; Jonathan Harris, MS 8 ; Jorge Gonzalez, BS 9 ; and Brandon Bucklen, PhD 8 Rothman Institute, Millburn, NJ 1 ; Coeur d’Alene Spine and Brain, Coeur d’Alene, ID 2 ; Southeastern Spine Institute, Mt Pleasant, SC 3 ; Salt Lake Orthopaedic Clinic, Salt Lake City, UT 4 ; South Carolina Sports Medical and Orthopaedic, North Charleston, NC 5 ; Coastal Orthopaedics, Norwalk, CT 6 ; Tulane Medical Center, New Orleans, LA 7 ; Globus Medical, Inc., Audubon, PA 8 ; and Drexel University, Philadelphia, PA 9 Introduction: Lateral lumbar interbody fusion (LLIF) provides indirect decompression of the neural elements while minimizing the potential vascular complications associated with anterior lumbar interbody fusion (ALIF). Posterior fixation may be applied through various techniques such as conventional minimally invasive surgery (CMIS), requiring the patient to be repositioned prone to provide access to both pedicles. Conversely, robot- assisted navigation (RAN) of pedicle screws can be performed from a single position without flipping the patient. RAN is theorized to reduce patient surgical time, radiation, and blood loss due to positioning and workflow effects. Aims/Objectives: Evaluate the effect of RAN compared to CMIS methods in terms of surgical time and radiation exposure. Methods: Twelve unembalmed human torsos were implanted with 2 level static LLIF cages, followed by posterior bilateral pedicle screw fixation using either CMIS (n=6) or RAN (n=6). Preoperative computed tomography (CT) RAN workflow utilized CT scans of the specimen taken offsite and transferred to the robotic system during setup. Screw planning was performed using these CT scans, which were merged with intraoperative fluoroscopy. Surgical times, radiation exposure, and breach score were measured. Patient flip time from a consecutive patient series was included. Results: Significant differences in surgical time and radiation dosages were found between groups. Surgical times for RAN and CMIS were 64.7±4.1 and 123.0±13.7 minutes, respectively. Posterior fixation times were 29.2±4.9 and 30.8±7.1 minutes, respectively (p>0.05). Times per screw for RAN and CMIS were 2.7±0.6 and 4.3±1.3 minutes, respectively (p<0.05). RAN resulted in significantly lower surgical time compared to CMIS (p<0.05). Radiation dosage and time were separated into interbody and posterior fixation, and sorted by imaging workflow. RAN and CMIS radiation exposure during screw CONCURRENT SESSION 2A: EMERGING & NAVIGATION FREE PAPERS Abstracts AnnualForum’19 15ANNUAL FORUM ’19 | LAS VEGAS, NEVADA | OCT. 31–NOV. 2, 2019 and rod insertion were 0.4±0.2 and 2.7±1.6 rads, respectively (p<0.05). RAN had a single grade-2 breach, averaging a breach score of 1.03, while CMIS had 4 total breaches with 2 grade-2 breaches and 2 grade-5 breaches averaging a breach score of 1.28 (p<0.05). Conclusions: Significant differences were found between conventional MIS and RAN technigues, with RAN resulting in shorter surgical times, less radiation exposure to the surgeon, and lower breach scores than CMIS. Consideration should be given to single-position LLIF procedures that utilize RAN to instrument the spine with bilateral pedicle screws. Disclosures: T. Protopsaltis: B; Globus Medical. J. Larson: B; Globus Medical. R. Frisch: A; Globus Medical. B; Globus Medical. F; Globus Medical. K. Huntsman: B; NuVasive. F; NuVasive, Titan Spine, ODC-SCI. T. Lansford: A; Orthofix, Globus Medical. B; Stryker K2M. R. Brady: A; Globus Medical. C; Globus Medical. C. Maulucci: None. G. Hayward II: E; Globus Medical. J. Harris: E; Globus Medical. J. Gonzalez: None. B. Bucklen: E; Globus Medical. Paper #12: Cervical Pedicle Screw Insertion Using O-Arm-Based 3D Navigation: Technical Advancement to Improve Screw Accuracy Keiji Wada; Ryo Tamaki; Tomohisa Inoue; and Ken Okazaki Tokyo Women's Medical University, Shinjuku-ku, Tokyo, Japan Introduction: Posterior cervical pedicle screw (CPS) placement is widely used for cervical posterior reconstruction. However, CPS placement has remained technically demanding. O-arm navigation system improved the accuracy of CPS placement, though there were several technical pitfalls. As surgical instruments and techniques for O-arm based surgery have been advanced, the accuracy of CPS placement might have also improved. However, there have been no reports describing the accuracy of CPS placement using O-arm based navigation on advances in surgical instruments and techniques. Aims/Objectives: This study aimed to investigate the accuracy and technical advancement of CPS placement in the lower cervical spine using intraoperative O-arm navigation. Methods: Forty patients who underwent lower cervical spine surgery with CPS using intraoperative O-arm navigation system between 2013 and 2018 were included in this study. Three different surgeons in our hospital performed the surgeries. We divided the above period into 3 phases according to the development of surgical techniques. In the first phase, we placed a reference frame onto the spinous process of the cranial vertebrae and used it for CPS placement at a maximum of 3 vertebral levels. The navigation guide sleeve was used to drill a screw hole, and then to tap and insert screws. A power drill was used to make the screw hole. In the second phase, we introduced a reference frame that can hold the spinous processes of 3 vertebrae, navigation tap, and navigation screw drivers. In the third phase, we developed a drill guide sleeve to minimize bending of the drill tip. We evaluated the accuracy of screw placement using postoperative computed tomography (CT). Screw placement accuracy was assessed using Neo’s classification: grade (G) 0, no perforation; G1, perforation <2 mm; G2, perforation 2-4 mm; G3, perforation >4 mm. Complications related to screw malpositioning were also evaluated. Results: Mean age at surgery was 67 years (range, 19-85). A total of 198 CPS were inserted: 68 in the first phase, 46 in the second phase, and 84 in the third phase. The total proportion of malpositioning was 5.6% (11 screws) and all were G1; 7.4% (5/68 screws) in the first phase, 10.9% (5/46 screws) in the second phase, and 1.2% (1/84 screws) in the third phase (p<0.05). There were no complications related to screw malpositioning. Conclusions: O-arm use dramatically improved CPS placement accuracy with the advancement of techniques and instruments. Disclosures: K. Wada: None. R. Tamaki: None. T. Inoue: None. K. Okazaki: None. Paper #13: Radiation Reduction Using Image Enhancement Technology Better Than ALARA Practice Alone In Lateral, Single-Position Lumbar Surgery BrettBraly, MD and Sam Hasan, RT The Spine Clinic of OKC, Oklahoma City, OK Introduction: As the use of minimally invasive surgical (MIS) techniques for spinal surgery has expanded, so has the reliance on intraoperative fluoroscopic imaging for anatomic identification as well as to visualize procedural steps. While MIS procedures have generally benefited patients with lower morbidity and faster return to normal function, the operating room (OR) staff and surgeons are thought to be exposed to significantly more radiation in these cases, which can lead to elevated rates of a variety of, and sometimes terminal, disease. Aims/Objectives: The purpose of this study was to evaluate radiation emission and surgical workflow differences CONCURRENT SESSION 2A: EMERGING & NAVIGATION FREE PAPERS Abstracts AnnualForum’19 16ANNUAL FORUM ’19 | LAS VEGAS, NEVADA | OCT. 31–NOV. 2, 2019 between lumbar interbody fusion procedures performed with intraoperative fluoroscopic use at standard ALARA-dose versus ALARA-dose settings with software-enhancement of image quality and incorporation of surgical workflow efficiency tools. Methods: A retrospective review of prospectively collected data was undertaken from a single site. A total of 68 patients were treated with single-level or 2-level lumbar interbody fusion: 34 with ALARA-dose fluoroscopic setting and 34 with low-dose capture and real-time image enhancement (LessRay, NuVasive, Inc.). The image enhancement software also included surgical efficiency tools (e.g., tracking to reduce/eliminate scouting shots). All patients were treated in the lateral position for both interbody fusion and bilateral pedicle screw and rod fixation. Interbody fusion was performed using either transpsoas lateral interbody fusion (XLIF, NuVasive, Inc.) or lateral-position anterior lumbar interbody fusion (ALIF) approaches. Screws were placed percutaneously in all cases. Results: All cases were successfully performed with the patient maintained in the lateral position for both interbody fusion and bilateral pedicle screw fixation. Mean total operative C-arm radiation emission was found to be significantly lower in the image-enhanced group compared to the standard ALARA- dose group: 33.3 milligray (mGy; standard deviation [std]: 18.4 mGy) vs. 52.2 mGy (std: 36.8 mGy), respectively (p<0.01). Mean total fluoroscopy time was found to be significantly lower in the image enhanced group compared to the standard-dose group: 110.6 seconds (std: 42.61 seconds) vs. 166.9 seconds (std: 51.87 seconds), respectively (p<0.0001). The effect of using intraoperative image enhancement of low-dose fluoroscopic images on both radiation emission and fluoroscopy time remained a significant factor when controlled for age, sex, BMI, procedure (XLIF vs. ALIF), and number of levels (single- vs. 2-level). Conclusions: Compared to ALARA-dose settings alone, the results of this preliminary comparative study suggest that using software enhancement of low-dose fluoroscopic images to perform lateral-position interbody fusion and posterior fixation reduces both radiation emission and fluoroscopic time. Disclosures: B. Braly: A; NuVasive. S. Hasan: None. Paper #14: Surgeons’ Intraoperative Radiation Exposure in Single- and Multi-level Minimally Invasive Transforaminal Lumbar Interbody Fusion Haruki Funao 1 ; Norihiro Isogai 1 ; Kodai Yoshida 2 ; Yutaka Sasao 1 ; Makoto Nishiyama 1 ; and Ken Ishii 1 International University of Health and Welfare, Tokyo, Japan 1 and International University of Health and Welfare Mita Hospital, Tokyo, Japan 2 Introduction: Surgeons risk exposure to fluoroscopic radiation in minimally invasive transforaminal lumbar interbody fusion (MIS TLIF). However, to date, only a few studies have prospectively evaluated radiation exposure with multiple measurements, therefore the radiation dose distribution of the whole body remains unclear. Aims/Objectives: To quantify the radiation doses received by surgeons during single- or multi-level MIS TLIF. Methods: Thirty-one consecutive patients who underwent 1- to 3-level MIS TLIF were prospectively enrolled in this study. The operating and assisting surgeons wore thermoluminescent dosimeter (TLD) badges at unshielded points—thyroid, chest, genitals, and right middle finger—and on the chest under a lead apron. The dose at the lens of the eye was calculated as the thyroid dose x 0.905. The effective dose was also calculated as defined by the International Commission on Radiation Units and Measurements. Patients’ demographics, fluoroscopic exposure time, and surgeons’ radiation doses were evaluated. Results: The patients included 16 males and 15 females, with a mean age of 59.7 years. MIS TLIF was performed at 1-level in 20 patients, at 2-level in 7 patients, and at 3-level in 4 patients. Mean fluoroscopy times were 38.7, 53.1, and 58.5 seconds for 1, 2, or 3 fusion levels, respectively. The mean radiation dose at the right middle finger was 0.33 millisievert (mSv) for the operating surgeon and 0.15 mSv for the assisting surgeon; for the operating surgeon, this dose was significantly higher than the doses measured elsewhere on the body (p<0.001), and significantly higher than the corresponding dose measured for the assisting surgeon (p<0.001). The assisting surgeon's mean dose at the right finger was also significantly higher than doses at the lens (p<0.001), thyroid (p<0.001), chest (p<0.001), or genitals (p=0.029). Interestingly, the operating surgeon's mean radiation dose at the genitals was 0.15 mSv, which was significantly higher than doses at the lens (p<0.001), thyroid (p<0.001), and chest (p=0.012); this dose was also significantly higher for the operating surgeon than for the assisting surgeon (p=0.014). The mean effective doses for the surgeon performing 1-, 2-, or 3-level MIS TLIF (0.06, 0.06, and 0.07 mSv) were not significantly different from those received by the assisting surgeon (0.04, 0.06, and 0.07 mSv). CONCURRENT SESSION 2A: EMERGING & NAVIGATION FREE PAPERS Abstracts AnnualForum’19 17ANNUAL FORUM ’19 | LAS VEGAS, NEVADA | OCT. 31–NOV. 2, 2019 Conclusions: The surgeons’ radiation exposure during MIS TLIF was within the safe level according to the International Commission on Radiological Protection's guidelines. However, the accumulated radiation exposure, especially to surgeon’s hands and genitals, should be carefully monitored. Disclosures: H. Funao: None. N. Isogai: None. K. Yoshida: None. Y. Sasao: None. M. Nishiyama: None. K. Ishii: None. Paper #15: A Review of Time-Demand, Radiation Exposure and Outcomes of Skin- Anchored Intraoperative 3D Navigation in Minimally Invasive Lumbar Spinal Surgery Avani Vaishnav, MBBS; Harvinder Sandhu, MD, MBA; Catherine Himo Gang, MPH; Steven McAnany, MD; Sravisht Iyer, MD; Todd Albert, MD; and Sheeraz Qureshi, MD, MBA Hospital for Special Surgery, New York, NY Introduction: Although 2D fluoroscopy has been the most commonly employed intraoperative imaging modality, intraoperative 3D navigation (ION) is increasingly being utilized. Currently, there is a paucity of literature on the use of skin- anchored ION for spinal surgery. Aims/Objectives: To evaluate the time-demand, radiation exposure, and outcomes of ION using a skin-anchored tracker in minimally invasive (MIS) lumbar surgery. Methods: A retrospective cohort study of all patients who underwent 1-level microdiscectomy, laminectomy or MIS transforaminal lumbar interbody fusions (TLIF) by single surgeon from Apr 2017-Jan 2019 was performed. Operative variables, radiation exposure, and perioperative outcomes were summarized using descriptive statistics. All cases were performed using Stryker SpineMask Tracker, Stryker SpineMap 3D Software and Stryker NAV3i Platform (Stryker Corp., Kalamazoo, MI). Results: Of the 232 patients, 92 underwent microdiscectomy, 65 laminectomy and 75 MIS TLIF. All procedures were performed using a tubular retractor system, operating microscope, and skin-anchored ION. Time for ION set-up (induction end to procedure start) was a median of 22, 23, and 24 minutes for microdiscectomy, laminectomy and MIS TLIF, respectively. This accounts for patient positioning, preparing and draping, placing the skin-anchored tracker, and intraoperative image-acquisition. Total fluoroscopy time was a median of 10 seconds for microdiscectomy, 9 for laminectomy, and 26 for MIS TLIF. Of this, average of 9 seconds was required for image-acquisition for ION, while the remaining was for the surgical procedure. Total radiation dose was a median of 15.2 mGy for microdiscectomy, 16.6 mGy for laminectomy and 44.6 mGy for MIS TLIF. Radiation dose for ION image-acquisition was 93%, 95%, and 37% of the total dose for microdiscectomy, laminectomy, and MIS TLIF, respectively, with the rest attributable to the surgical procedure. The operative time was a median of 42 minutes for microdiscectomy, 50 minutes for laminectomy, and 92 minutes for MIS TLIF. For all procedures, median blood loss was 25 mL; the only intra-operative complication was a durotomy in 1 patient undergoing laminectomy, and the most common in-hospital complication was urinary retention requiring catheterization occurring in 0%, 3.1%, and 6.7% of microdiscectomies, laminectomies, and MIS-TLIF, respectively. There were no wrong-level surgeries in any patients. Conclusions: The results of our study show that the use of intraoperative navigation using a skin-anchored tracker is a feasible, safe, and accurate approach. For decompression surgeries, a majority of the radiation is attributable to ION image-acquisition, whereas it accounts for <50% of the radiation exposure in MIS TLIF. Overall, the use of ION results in low radiation exposure, short operative times, and minimal complications. Disclosures: A. Vaishnav: None. H. Sandhu: B; BioRestorative Therapies. D; Amedica, BioRestorative Therapies, Paradigm Spine, Prosidyan, Providence Medical Technology, Spine Wave. C. Gang: None. S. McAnany: B; Titan, NuVasive, Stryker K2M. S. Iyer: A; NASS. B; Healthgrades. T. Albert: B; NuVasive, Facet-Link. D; Gentis, Bonovo Orthopedics, Biometrix, InVivo Therapeutics, Spinicity, Crosstrees Medical, Paradigm Spine, Invuity, ASIP, PMIG, Vital 5, Innovative Surgical Designs, CytoDyn, Morphogenesis, Surg. io, Nutriceutical Holdings PRN, Strathspey Crown, Pulse Equity Partners, Augmedics, UnitedHealth Group. F; Zimmer Biomet, DePuy Synthes. S. Qureshi: B; Stryker K2M, Globus Medical, Paradigm Spine, Spinal Simplicity, Lifelink.com. D; Avaz Surgical, Vital 5. F; RTI, Stryker K2M. CONCURRENT SESSION 2A: EMERGING & NAVIGATION FREE PAPERS Abstracts AnnualForum’19 18ANNUAL FORUM ’19 | LAS VEGAS, NEVADA | OCT. 31–NOV. 2, 2019 Paper #16: Defining MIS TLIF: A Systematic Review of Techniques and Technologies Used by Surgeons Worldwide Sertac Kirnaz, MD; Robert Nick Hernandez, MD; Sara Lener, MD; Christoph Wipplinger, MD; Franziska Schmidt, MD; and Roger Hartl, MD Weill Cornell Medicine, New York, NY Introduction: Since its introduction, the MIS TLIF has demonstrated fewer complications, less intraoperative blood loss, shorter hospital stay and recovery time, and less postoperative narcotic use with similar clinical outcomes and fusion rates compared to conventional open TLIF. To date there is no consensus among surgeons as to what defines an MIS TLIF compared to an open or mini-open TLIF. Aims/Objectives: This systematic review aimed to examine the MIS TLIF techniques reported in the recent body of literature to help provide a definition of what constitutes MIS TLIF, based on the consensus of the majority of surgeons. Methods: We created a database of articles published about MIS TLIF between 2010 and 2018. We evaluated the technical components of the MIS TLIF including instruments and incisions used as well the order in which key steps are performed. Results: A total of 75 studies with 7808 patients (4920 treated with MIS TLIF) were included in the analysis. We could identify several patterns for MIS TLIF performance that seemed agreed upon by the majority of MIS surgeons: Use of paramedian incisions; use of a tubular retractor to perform a total facetectomy, decompression, and interbody cage implantation; and percutaneous insertion of the pedicle-screw rod constructs with intraoperative imaging. Conclusions: Based on this review of the literature, the key features used by surgeons performing MIS- TLIF include the use of non-expandable or expandable tubular retractors, a paramedian or lateral incision, and the use of a microscope or endoscope for visualization. Approaches using expandable non- tubular retractors, those that require extensive subperiosteal dissection from the midline laterally, or specular-based retractors with wide pedicle to pedicle exposure are far less likely to be promoted as an MIS-based approach. A definition is necessary to improve the communication among spine surgeons in research as well as patient education. Disclosures: S. Kirnaz: None. R. Hernandez: None. S. Lener: None. C. Wipplinger: None. F. Schmidt: None. R. Hartl: B; Ulrich, Brainlab, DePuy Synthes. F; Zimmer Biomet. Paper #17: A Comparison of Minimally Invasive and Open Transforaminal Lumbar Interbody Fusion for Grade 1 Degenerative Lumbar Spondylolisthesis: An Analysis of the Prospective, Quality Outcomes Database Andrew Chan, MD 1 ; Erica Bisson, MD, MPH 2 ; Mohamad Bydon, MD 3 ; Steven Glassman, MD 4 ; Kevin Foley, MD 5 ; Christopher Shaffrey, MD 6 ; Eric Potts, MD 7 ; Mark Shaffrey, MD 8 ; Domagoj Coric, MD 9 ; John Knightly, MD 10 ; Paul Park, MD 11 ; Michael Wang, MD 12 ; Kai-Ming Fu, MD, PhD 13 ; Jonathan Slotkin, MD 14 ; Anthony Asher, MD 9 ; Michael Virk, MD, PhD 13 ; Panagiotis Kerezoudis, MD, M.S. 3 ; Mohammed Alvi, M.B.BS 3 ; Jian Guan, MD 2 ; Brenton Pennicooke, MD 13 ; Regis Haid, MD 15 ; and Praveen Mummaneni, MD 1 University of California, San Francisco, San Francisco, CA 1 ; University of Utah, Salt Lake City, UT 2 ; Mayo Clinic, Rochester, MN 3 ; Norton Leatherman Spine Center, Louisville, KY 4 ; Semmes-Murphey Neurologic and Spine Institute, Memphis, TN 5 ; Duke University, Durham, NC 6 ; Goodman Campbell Brain and Spine, Indianapolis, IN 7 ; University of Virginia, Charlottesville, VA 8 ; Carolina Neurosurgery & Spine Associates, Charlotte, NC 9 ; Atlantic Neurosurgical Specialists, Morristown, NJ 10 ; University of Michigan, Ann Arbor, MI 11 ; University of Miami, Miami, FL 12 ; Weill Cornell Medical Center, New York, NY 13 ; Geisinger Health, Danville, PA 14 ; and Atlanta Brain and Spine Care, Atlanta, GA 15 Introduction: Minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) has been applied to degenerative lumbar spondylolisthesis and is associated with expedited recovery, reduced operative blood loss, and shorter lengths of hospitalization compared to traditional, open TLIF. However, the impact of MIS TLIF on long-term patient-reported outcomes (PROs) is less clear. Aims/Objectives: Here, we compare MIS TLIF to traditional, open TLIF for Grade 1 degenerative lumbar spondylolisthesis in the largest study to date by sample size. Methods: We utilized the multicenter, prospective Quality Outcomes Database registry and queried patients with Grade 1 degenerative lumbar spondylolisthesis who underwent single-segment surgery with fully minimally invasive or open TLIF methods. Outcomes were compared 24 months postoperatively: Oswestry Disability Index (ODI), Numeric Rating Scale Back Pain (NRS-BP), NRS Leg Pain (NRS-LP), EuroQol-5D (EQ-5D), North American Spine Society (NASS) Satisfaction Score, cumulative reoperation rate, and return to work (RTW) rate. Multivariate analyses were utilized to adjust for variables reaching p<0.20 on univariate analyses. Results: A total of 297 patients were included: 72 (24.2%) underwent MIS TLIF and 225 (75.8%) open TLIF. Average age was similar between MIS TLIF and open TLIF (62.1 years vs. 59.5 years, respectively; p=0.10). MIS TLIF surgeries were CONCURRENT SESSION 2B: DEGENERATIVE & POSTERIOR FREE PAPERS Abstracts AnnualForum’19 19ANNUAL FORUM ’19 | LAS VEGAS, NEVADA | OCT. 31–NOV. 2, 2019 associated with lower body mass index (29.5±5.1 vs. 31.3±7.0, p=0.0497) and more workman’s compensation cases (11.1% vs. 1.3%, p=0.001) compared with open TLIF. Patients did not differ significantly at baseline for ODI, NRS BP, NRS LP, and EQ-5D (p>0.05). MIS TLIF was associated with less blood loss (108.8±85.6 vs. 299.6±242.2 mL, p<0.001), longer operations (228.2±111.5 vs. 189.6±66.5 min, p<0.001), and a trend toward decreased length of hospitalization (2.9±1.8 vs. 3.3±1.6 days, p=0.08). Discharge disposition to home was similar (94.4% vs. 91.1%, p=0.38). Both cohorts improved significantly from baseline for 24-month ODI, NRS-BP, NRS-LP, and EQ- 5D (p>0.001). In adjusted analyses, MIS TLIF was associated with superior ODI ( β =-4.7; 95%CI 9.3— -0.04; p=0.048) and EQ-5D ( β =0.06;95%CI 0.009-0.11; p=0.02). Though trends for superiority were evident for MIS TLIF, they did not reach statistical significance for NRS-BP (p=0.06), NRS-LP (p=0.07), and NASS Satisfaction (p=0.06). Similarly, there was a trend for fewer reoperations following MIS TLIF, though this did not reach statistical significance (1.4% vs. 7.6%, p=0.10). A higher proportion of MIS TLIF patients were able to RTW following surgery (100% vs. 80%, p=0.02). Conclusions: For single-level Grade 1 degenerative lumbar spondylolisthesis, MIS TLIF was associated with superior outcomes for disability and quality of life compared with traditional, open TLIF. MIS TLIF was associated with higher rates of RTW and less blood loss, but longer operative times. These results suggest that in well-selected patients, MIS TLIF may be superior to traditional, open TLIF for Grade 1 degenerative lumbar spondylolisthesis. Disclosures: A. Chan: A; Research support for unrelated study from Orthofix, Inc. E. Bisson: B; nView. M. Bydon: None. S. Glassman: A; NuVasive (provides funds directly to the database company; no funds are paid directly to individual or institution). B; Medtronic. D; Medtronic. F; Medtronic. K. Foley: B; Medtronic. D; Medtronic, NuVasive, Spine Wave. F; Medtronic. C. Shaffrey: B; NuVasive, Zimmer Biomet. D; NuVasive. F; NuVasive, Medtronic, Zimmer Biomet. E. Potts: None. M. Shaffrey: None. D. Coric: B; Spine Wave, Stryker K2M, Medtronic, Premia Spine. D; Spine Wave, Premia Spine, Spinal Kinetics. J. Knightly: None. P. Park: B; Globus Medical, NuVasive, AlloSource, Medtronic. F; Globus Medical. M. Wang: A; Department of Defense. B; DePuy Synthes, JoiMax USA, Stryker K2M, Aesculap Spine, Vallum. D; Spinicity. F; DePuy Synthes. K. Fu: B; SI-BONE. J. Slotkin: B; Stryker K2M. A. Asher: None. M. Virk: B; Globus Medical, DePuy Synthes, Brainlab. P. Kerezoudis: None. M. Alvi: None. J. Guan: None. B. Pennicooke: None. R. Haid: B; NuVasive. D; Spine Universe. F; NuVasive, Medtronic. P. Mummaneni: A; NREF, AOSpine. B; DePuy Synthes, Globus Medical, Stryker K2M. C; Spineart. D; Spinicity. F; DePuy Synthes, Thieme Publishers, Springer Publishers. Paper #18: The Impact of Comorbidity Burden on Postoperative PROMIS Physical Function Following Minimally Invasive Transforaminal Lumbar Interbody Fusion Nathaniel W. Jenkins, MS; James M. Parrish, MPH; Thomas Brundage, BS; Nadia Hrynewycz, BS; Joon Yoo, BA; and Kern Singh, MD Rush University Medical Center, Chicago, IL Introduction: Patient-Reported Outcome Measurement Information System (PROMIS) has been widely implemented to evaluate patient health before and after a variety of orthopedic and spinal procedures. The PROMIS Physical Function (PF) domain has been particularly valuable in spine surgery due to its ability to accurately assess strength, mobility, and coordination. While previous studies have investigated the effect of comorbidity burden on perioperative outcomes, few have evaluated these variables in longterm clinical recovery following common spinal procedures such as minimally invasive transforaminal lumbar interbody fusion (MIS TLIF). Aims/Objectives: To assess the utility of PROMIS PF to differentiate the clinical recovery of patients with differing comorbidity burdens in the setting of MIS TLIF. Methods: Patients undergoing primary, 1- to 2-level MIS TLIF were retrospectively reviewed and stratified based on Charlson Comorbidity Index (CCI) score: 0 points (no comorbidities), 1-2 points (low CCI), ≥3 points (high CCI). CCI was tested for an association with demographic characteristics and perioperative variables using Chi-squared analysis and multivariate linear regression. Multivariate linear regression was utilized to determine the association between CCI cohorts and PROMIS PF. Results: A total of 187 patients were included: 53 had no comorbidities, 78 had a low CCI, and 56 a high CCI. Patients with higher comorbidities were older, more likely to be smokers, to be diabetics, and have hypertension. However, no differences in gender, BMI, and perioperative characteristics were identified amongst cohorts. Patients in the 3 cohorts reported similar PROMIS PF scores preoperatively and up to 1-year postoperatively. Additionally, each cohort experienced a similar improvement in PROMIS PF scores from baseline at each postoperative timepoint. For patients without comorbidities, the change in the postoperative PROMIS PF score from baseline was significant at every postoperative timepoint. However, for the patients with 1 or more comorbidities, the change in the postoperative PROMIS PF score from baseline was significant at the 3-month, 6-month, and 1-year time points (p≤0.003), however, the change from baseline to 6-weeks was not significant. CONCURRENT SESSION 2B: DEGENERATIVE & POSTERIOR FREE PAPERS Next >