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Study Design: Retrospective cohort study., Objective: Decompression for the treatment of lumbar spinal stenosis (LSS) has shown excellent clinical outcomes. In patients with symptomatic single level stenosis and asymptomatic adjacent level disease, it is unknown whether decompressing only the symptomatic level is sufficient. The objective of this study is to compare outcomes between single level and dual level minimally invasive (MIS) decompression in patients with adjacent level stenosis., Methods: The current study is a retrospective review of patients undergoing primary single or dual level MIS decompression for LSS. Radiographic stenosis severity was graded using the Schizas grading. Patients undergoing single level decompression (SLD) with moderate stenosis at the adjacent level were compared with patients undergoing dual level decompression (DLD) for multi-level LSS. Clinical outcomes, complications, and reoperations were compared. Subgroup analysis was performed on patients with the same Schizas grade at the adjacent level in the SLD group and the second surgical level in the DLD group., Results: 148 patients were included (126 SLD, 76 DLD). There were no significant differences in patient reported outcomes between the two groups at any timepoint up to 2 years postoperatively, including in the matched stenosis severity subgroups. Operative time was longer in the DLD cohort ( P < 0.001). There were no significant differences in complications or reoperation rates., Conclusion: In patients with single level symptomatic LSS and adjacent level stenosis, decompression of only the symptomatic level provided equivalent clinical outcomes compared to dual level decompression. The additional operative time and potential incremental risk of dual level surgery may not be justified., Competing Interests: Declaration of conflicting interestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: State: HS2, LLC Ownership/Equity/Investment Innovasis Research Support (either personally or through HSS) Globus Medical, Inc. Speakers’ Bureau Intrinsic Therapeutics Inc. Other Bioventus Consulting HSS AND ASC Development Network Ownership/Equity/Investment. Sheeraz Qureshi has the following disclosures: AMOpportunities: Other financial or material support; Annals of Translational Medicine: Editorial or governing board; Association of Bone and Joint Surgeons: Board or committee member; Cervical Spine Research Society: Board or committee member; Contemporary Spine Surgery: Editorial or governing board; Globus Medical: IP royalties; Paid consultant; Paid presenter or speaker; Hospital Special Surgery Journal: Editorial or governing board; HS2, LLC: Stock or stock Options; International Society for the Advancement of Spine Surgery (ISASS) - Program Committee member: Board or committee member; Lifelink.com: Other financial or material support; Lumbar Spine Research Society: Board or committee member; Minimally Invasive Spine Study Group: Board or committee member; North American Spine Society: Board or committee member; Simplify Medical, Inc.: Other financial or material support; Society of Minimally Invasive Spine Surgery (SMISS) - Program Committee member: Board or committee member; Spinal Simplicity: Other financial or material support; SpineGuard, Inc.: Paid consultant; Stryker: IP royalties; Paid consultant; Surgalign: Paid consultant; Tissue Differentiation Intelligence: Stock or stock Options; Viseon, Inc.: Paid consultant; Research support. Sravisht Iyer has the following disclosures: Globus Medical: Paid presenter or speaker; Stryker: Paid presenter or speaker; Vertebral Columns/International Society for the Advancement of Spine Surgery (ISASS): Editorial or governing board.

Study Design: Cross-sectional radioanatomic study., Objective: To determine the feasibility of performing an anterior column realignment (ACR) using an anterior-to-psoas (ATP) approach at L1-L5., Methods: Axial magnetic resonance images (MRI) of the L1-L5 disc levels obtained at a single institution were obtained and analyzed. The feasibility of performing an ACR was assessed using a combination of the size of the left oblique corridor (OC), the psoas morphology using the modified Moro classification, and the anterior disc edge to great vessel distance., Results: Three hundred MRI studies obtained from 300 patients were included. All patients had a measurable left OC at the L1-L4 levels. Twenty patients (6.7%) had no measurable OC at the L4-L5 level. According to the modified Moro's classification, a high-rising psoas was seen in 4 patients (1.3%) at the L3-L4 level and 57 patients (19.0%) at the L4-L5 level. An ALL release was considered high risk due to no measurable space between the anterior disc edge and the great vessels in 54 patients (18.0%) at the L1-L2 level, 39 patients (13.0%) at the L2-L3 level, 119 patients (39.7%) at the L3-L4 level, and 226 patients (75.3%) at the L4-L5 level., Conclusion: ACR using an ATP approach is the most radioanatomically feasible at L2-L3. The L4-L5 level has the highest risk with regards to both the ATP approach and the ALL release for an ACR due to high rates of unmeasurable left OC and space between the anterior disc edge and the great vessels., Competing Interests: Declaration of Conflicting InterestThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Rex Marco has the following disclosures: DePuy, A Johnson & Johnson Company: Paid presenter or speaker Globus Medical: IP royalties.

Study Design: Cadaveric study., Objective: Compare discectomy performance between transforaminal lumbar interbody fusion (TLIF) done via an endoscopic versus a tubular technique., Summary of Background Data: Performance of an adequate discectomy is essential to lumbar fusion when performing a TLIF. Previous cadaveric studies comparing open and minimally invasive techniques have reported 36.6%-80% discectomy. There is controversy whether an endoscopic TLIF (E-TLIF) can allow for an adequate discectomy., Materials/methods: An E-TLIF was performed on 14 discs (T12-L5) and a minimally invasive tubular TLIF (T-TLIF) was performed on 15 discs (T12-L4, L5-S1). Fellowship trained surgeons performed the TLIFs. Each disc was transected after discectomy and a digital image was analyzed using an imaging processing software to determine the percent of discectomy. Each quadrant of the discectomy was compared. Quadrant one was defined as the left posterior-ipsilateral quadrant of the disc, with each quadrant numbered 2-4 clockwise around the disc. The time to perform the discectomy was compared. Pedicle screws were placed contralaterally to the TLIF and the change in interpedicular distance was compared between techniques after expandable cage implantation as a marker for indirect decompression. A student's t-test was used to determine statistical significance., Results: There was no difference in discectomy performance between techniques (48.86%+/-6.98% T-TLIF vs. 50.26%+/-7.38% E-TLIF, P=0.61). There was no statistical difference between T-TLIF vs E-TLIF at quadrants 1, 3 and 4. There was a difference in discectomy performance at quadrant 2 (39.02%+/-10.18% T-TLIF vs 50.13%+/-14.00% E-TLIF, P=0.02). There was no statistical difference between interpedicular distance created (2.20 mm+/-1.97 mm T-TLIF vs 1.36 mm+/-1.82 mm E-TLIF, P=0.24). E-TLIF took less time than MIS-TLIF (20.00 min+/-7.12 min vs 15.22 min+/-4.42 min, P=0.048)., Conclusion: Our cadaveric study demonstrates that an adequately performed E-TLIF discectomy may be comparable to a T-TLIF discectomy. Further research is required to maximize the efficiency and instrumentation of this technique., Competing Interests: Conflict of Interest: Sohrab Virk is a consultant for LifeSpine., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Single center, retrospective cohort study., Objectives: Little is known about the surgical outcomes and quality of life in patients with C2-sacrum posterior spinal fusion (PSF). Though it is thought to be a "final" construct, it remains unknown how patients fare postoperatively. We sought to evaluate the surgical outcomes and quality of life of patients after C2-sacrum PSF., Methods: Consecutive patients undergoing C2-Sacrum PSF from 2015-2020 by 4 surgeons at a single institution were included. The study time period for each patient began after their index operation that led to the C2-sacrum fusion. Dates of surgery, complications, reoperations, patient reported outcomes (PROs) including EuroQol 5 Dimensions (EQ-5D), Oswestry Disability Index (ODI), Scoliosis Research Society (SRS) questionnaires, and activities of daily living (ADL) questions were collected and analyzed. Descriptive statistics, paired t-tests, student t-tests, and linear regression were used., Results: Of the 23 patients who underwent C2-sacrum PSF, 6 patients (26%) required a total of 10 reoperations after a mean of 1.5 years (range 0-4 years) after C2-sacrum PSF. Five reoperations were for mechanical failure; 3 for wound complications/infection; and 2 for instrumentation and spinous process prominence. PROs were collected on 18 patients with mean follow-up of 2.4 years (range .5-4.5) after their C2-sacrum PSF. At 6-months, both SRS-22 and ODI scores improved significantly after C2-sacrum PSF (SRS: 57.5 to 76.3, P = .0014; ODI: 47.0 to 31.7, P = .013). Similarly, at a mean 2.4 years postoperatively, mean ODI improved significantly (47.0 to 30.4, P = .0032). Six patients (33%) had minimal symptoms (ODI <20). The median postoperative EQ-5D score was .74 (range .19 to 1.0), which compares favorably to patients with hip/knee osteoarthritis (EQ-5D .63) and diabetes mellitus (DM) (EQ-5D .69) and hypertension (HTN). In terms of activities of daily living (ADL), 10 patients (56%) exercised regularly-a mean 4.5 days/week. 11 (61%) could do light aerobic activity (e.g. stationary bike). 10 (55%) were able to play with children/grandchildren as desired. Eight patients (44%) hiked, and 2 (11%) drove independently. 11 (61%) could tolerate short air-travel comfortably. Of the 17 patients who could toilet and perform basic hygiene preoperatively, 16 (94%) were able to do so postoperatively., Conclusion: Though C2-sacrum PSF is thought to be a "final" construct, approximately 1 in 4 patients require subsequent operations. However, C2-sacrum PSF patients had a significant improvement in SRS and ODI scores by 6 months postop. Over 60% of patients were regularly performing light aerobic activity 2 years after their C2-sacrum PSF. EQ-5D suggests that this population fares better than those with degenerative hip/knee arthritis and similarly to those with common chronic conditions like DM and HTN., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objective: /Hypothesis: Patients undergoing C2-sacrum PSF have unique medical histories and multiple prior operations over an extended period., Design: Single center, retrospective cohort., Methods: Consecutive C2-sacrum PSF patients operated on by 4 surgeons at a single-center from 2015-2020 were reviewed. Demographics, comorbidities, indications, surgical history, and radiographic parameters were collected., Results: 23 patients underwent C2-sacrum PSF. 13 (57%) were male, and 21 (91.3%) were adults. Mean age at time of first spine surgery was 44 years (range 5-71) and 53 years (range 14-72) at the time of C2-sacrum PSF. Six patients (26%) had osteoporosis, and 6 patients (26%) had neurologic comorbidities-including Parkinson's disease (4), cerebral palsy (1), and Brown Sequard syndrome (1). Four (17%) had connective tissue disease. Two patients underwent C2-sacrum PSF as an index procedure: (1) 67M with myelomatous fractures and 124° of cervicothoracic kyphosis; (2) 28F with severe Marfan syndrome with 140° thoracic scoliosis and 130° thoracic kyphosis. The remaining 21 (91%) underwent C2-sacrum PSF as a revision following prior spinal surgeries on average, 4 previous surgeries (range 1-13) over 10.5 years (range .3-37.4). Indications for the remaining 21 C2-sacrum PSF revision procedures included 17 (81%) for kyphosis (5 of whom also had significant coronal deformity), 1 (5%) for only coronal malalignment, 2 (10%) for instrumentation failure, and 1 (5%) for myelopathy., Conclusions: 91% (21/23) of patients requiring C2-sacrum PSF were treated as revisions of prior fusions, with a mean of 4 prior surgeries over 10 years. Over 80% of these patients underwent C2-sacrum PSF to address kyphosis. 26% had neurologic conditions, and 26% had osteoporosis., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Case: A 19-year-old man underwent arthroscopic posterior glenoid reconstruction with a distal tibia allograft (DTA) after failing 2 posterior, soft-tissue instability surgeries. Although he experienced near-complete resolution of symptoms and return to sport, graft resorption was noted 7 months postoperatively. The patient underwent revision surgery for screw removal., Conclusion: Graft resorption has not previously been reported in the setting of arthroscopic DTA use for posterior instability. It is believed that stress shielding contributed to resorption. In such situations, screw removal may be warranted. Consideration of alternative fixation techniques and additional investigation into the causes, clinical significance, and optimal management of posterior DTA resorption are warranted., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSCC/C318)., (Copyright © 2024 by The Journal of Bone and Joint Surgery, Incorporated.)

Study Design: Systematic Review., Objective: 3DP technology use has become increasingly more common in the field of medicine and is notable for its growing utility in spine surgery applications. Many studies have evaluated the use of pedicle screw placement guides and spine models in adult spine patients, but there is little evidence assessing its efficacy in pediatric spine patient populations. This systematic review identifies and evaluates the current applications and surgical outcomes of 3-Dimensional Printing (3DP) technology in pediatric spinal surgery., Methods: A search of publications was conducted using literature databases and relevant keywords in concordance with PRISMA guidelines. Inclusion criteria consisted of original studies, and studies focusing on the use of 3DP technology in pediatric spinal surgery. Studies with a focus on adult populations, non-deformity surgery, animal subjects, systematic or literature reviews, editorials, or non-English studies were excluded from further analysis., Results: After application of inclusion/exclusion criteria, we identified 25 studies with 3DP applications in pediatric spinal surgery. Overall, the studies found significantly improved screw placement accuracy using 3DP pedicle screw placement guides but did not identify significant differences in operative time or blood loss. All studies that utilized 3D spine models in preoperative planning found it helpful and noted an increased screw placement accuracy rate of 89.9%., Conclusions: 3DP applications and techniques are currently used in pre-operative planning using pedicle screw drill guides and spine models to improve patient outcomes in pediatric spinal deformity patients., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Prerana Katiyar, Venkat Boddapati, Josephine Coury, and Benjamine Roye have no financial interests. Michael Vitale receives royalties from Zimmer Biomet, is a consultant for NuVasive and Stryker, is on the board of directors for Children’s Spine Foundation and Pediatric Orthopedic Society of North America, and has current grant/research support from Scoliosis Research Society, Children’s Spine Foundation and Pediatric Orthopedic Society of North America, and the Orthopedic Scientific Research Foundation. Lawrence Lenke has received royalties from Medtronic, consulting fees from Medtronic and Acuity Surgical, and is a reviewer for the following journals: Spine, The Spine Journal, European Spine Journal, AO Spine Deformity Knowledge Forum, JBJS, GSJ, ISSG, Spine Deformity.

Study Design: Systematic review., Objective: To examine the outcomes of customized 3-dimensional (3D) printed implants for spinal reconstruction after tumor resection., Summary of Background Data: Various techniques exist for spinal reconstruction after tumor resection. Currently, there is no consensus regarding the utility of customized 3D-printed implants for spinal reconstruction after tumor resection., Materials and Methods: A systematic review was registered with PROSPERO and performed according to "Preferred Reporting Items for Systematic Reviews and Meta-analyses" guidelines. All level I-V evidence studies reporting the use of 3D-printed implants for spinal reconstruction after tumor resection were included., Results: Eleven studies (65 patients; mean age, 40.9 ± 18.1 y) were included. Eleven patients (16.9%) underwent intralesional resections with positive margins and 54 patients (83.1%) underwent en bloc spondylectomy with negative margins. All patients underwent vertebral reconstruction with 3D-printed titanium implants. Tumor involvement was in the cervical spine in 21 patients (32.3%), thoracic spine in 29 patients (44.6%), thoracolumbar junction in 2 patients (3.1%), and lumbar spine in 13 patients (20.0%). Ten studies with 62 patients reported perioperative outcomes radiologic/oncologic status at final follow-up. At the mean final follow-up of 18.5 ± 9.8 months, 47 patients (75.8%) had no evidence of disease, 9 patients (14.5%) were alive with recurrence, and 6 patients (9.7%) had died of disease. One patient who underwent C3-C5 en bloc spondylectomy had an asymptomatic subsidence of 2.7 mm at the final follow-up. Twenty patients that underwent thoracic and/or lumbar reconstruction had a mean subsidence of 3.8 ± 4.7 mm at the final follow-up; however, only 1 patient had a symptomatic subsidence that required revision surgery. Eleven patients (17.7%) had one or more major complications., Conclusion: There is some evidence to suggest that using customized 3D-printed titanium or titanium alloy implants is an effective technique for spinal reconstruction after tumor resection. There is a high incidence of asymptomatic subsidence and major complications that are similar to other methods of reconstruction., Level of Evidence: Level V, systematic review of level I-V studies., Competing Interests: T.H. was supported by a Burroughs Wellcome Fund Physician Scientist Institutional Award to the Texas A&M University Academy of Physician Scientists. C.S.: Acquisition of Vertera Inc. by NuVasive’ Shares: stock or stock options. R.A.W.M.: Globus Medical: Royalties. J.E.B.: GT Medical Technologies: paid consultant. The remaining authors declare no conflict of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Cadaveric specimens., Objective: To perform a pathomorphological analysis of the degree of facet joint (FJ) degeneration utilizing fresh cadaveric models and correlating these structural changes with imaging findings., Methods: L1-L5 FSU including all tissue between the anterior longitudinal ligament to the posterior spinal structures were obtained on 28 patients at a mean of 5.7 hours post-mortem. The samples were fixed in an agar medium and CT and MRI were performed. The level of FJ degeneration was identified based on prior classifications Osteoarthritis Research Society International (OARSI), as was the facet angle and tropism. Pathomorphological assessment including articular cartilage cell density was performed according to prior established methodology., Results: Radiographically, a direct association was identified between FJ degeneration and patient age. Facet angle and tropism did not significantly vary by patient age. Pathomorphologically, there was a decrease in the cellular density of articular cartilage with increasing patient age. Similarly, there was a significant direct correlation between radiographic degree of degenerative changes in FJs with the age of cadavers and the degree of degeneration of FJs according to the morphological classification of OARSI, as well as a significant inverse correlation with cell density., Conclusion: A comprehensive assessment of various signs of FJ degeneration using cadaveric material has established that, based on radiographic imaging, it is possible to assess the microstructural state of FJ, including at an early stage of the disease. This data may be useful for surgeons in guiding therapeutic strategies based on individual biometric parameters of the FJ., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Neck injury is a common and often debilitating injury among athletes participating in American football. Limited data exists regarding neck injuries among elite athletes in the National Football League (NFL). To characterize the epidemiology of non-season ending, season-ending, and career-ending neck injuries in the NFL from 2016 through 2021., Methods: Athletes who sustained neck injuries were identified using the NFL's injured reserve (IR) list between the 2016 and 2021 seasons. Demographics and return to sport (RTS) data were collected. Available game footages were reviewed to identify the mechanism of injury (MOI). Injury incidence rates were calculated based on per team play basis., Results: During the 6-year study period, 464 players (mean age 26.8 ± 3.2 years) were placed on the injury reserve list due to neck injuries. There were 285 defensive players and 179 offensive players injured (61.4 vs 38.6%, respectively, p < 0.001). Defensive back was the most common position to sustain a neck injury (111 players, 23.9%). 407 players (87.7%) sustained non-season-ending injuries with a mean RTS at 9.2 ± 11.3 days. 36 players (7.8%) sustained season-ending injuries with a mean RTS at 378.6 ± 162.0 days. 21 players (4.5%) sustained career-ending injuries. The overall incidence of neck injuries was 23.5 per 10,000 team plays. The incidence of season-ending injuries and career-ending injuries were 1.82 and 1.06 per 10,000 team plays, respectively. There were 38 injuries with available footages for MOI assessment (23 non-season-ending, 9 season-ending, 6 career-ending). Head-to-head contact was seen in 15 injuries (39.5%), head-down tackling in 11 injuries (28.9%), direct extremity-to-head contact in 7 injuries (18.4%), and head-to-ground contact in 5 injuries (13.2%). There was no significant difference in age, position, or MOI among players sustaining non-season-ending, season-ending, and career-ending injuries., Conclusion: There is a high incidence of neck injuries among NFL athletes with predictable MOIs including head-to-head contact, head-down tackling, direct extremity-to-head contact, and head-to-ground contact. Defensive players were more likely to sustain neck injuries compared to offensive players. Defensive back was the most common position to sustain a neck injury., Level of Evidence: III., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Study Design: Prospective single-cohort analysis., Objectives: To compare the outcomes/complications of 2 robotic systems for spine surgery., Methods: Adult patients (≥18-years-old) who underwent robot-assisted spine surgery from 2016-2019 were assessed. A propensity score matching (PSM) algorithm was used to match Mazor X to Renaissance cases. Preoperative CT scan for planning and an intraoperative O-arm for screw evaluation were preformed. Outcomes included screw accuracy, robot time/screw, robot abandonment, and radiation. Screw accuracy was measured using Vitrea Core software by 2 orthopedic surgeons. Screw breach was measured according to the Gertzbein/Robbins classification., Results: After PSA, a total of 65 patients (Renaissance: 22 vs. X: 43) were included. Patient/operative factors were similar between robot systems ( P > .05). The pedicle screw accuracy was similar between robots (Renaissance: 1.1%% vs. X: 1.3%, P = .786); however, the S2AI screw breach rate was significantly lower for the X (Renaissance: 9.5% vs. X: 1.2%, P = .025). Robot time per screw was not statistically different (Renaissance: 4.6 minutes vs. X: 3.9 minutes, P = .246). The X was more reliable with an abandonment rate of 2.3% vs. Renaissance:22.7%, P = .007. Radiation exposure were not different between robot systems. Non-robot related complications including dural tear, loss of motor/sensory function, and blood transfusion were similar between robot systems., Conclusion: This is the first comparative analyses of screw accuracy, robot time/screw, robot abandonment, and radiation exposure between the Mazor X and Renaissance systems. There are substantial improvements in the X robot, particularly in the perioperative planning processes, which likely contribute to the X's superiority in S2AI screw accuracy by nearly 8-fold and robot reliability by nearly 10-fold.

Purpose: Despite the extensive use of PROs in ankle fracture research, no study has quantified which PROs are most commonly used for assessing outcomes of patients who sustain fractures of the posterior malleolus. The purpose of this study was therefore to quantify which PROs are most commonly used for outcome research after posterior malleolus fractures., Methods: A systematic search was performed using the preferred reporting items for systematic reviews and meta-analyses guidelines. Articles were identified through Pubmed, EMBASE, Web of Science, and cochrane central register of controlled trials through May of 2021. Included articles were analyzed for the primary outcome of the most commonly reported PRO., Results: The American orthopedic foot and ankle ankle-hindfoot score (AOFAS) was the most commonly used PRO for assessment of posterior malleolus fracture outcomes, used in 37 of 72 studies (51.4%). The second and third most common were the olerud-molander ankle score (OMAS) (22 studies, 30.6%) and the visual analogue score (VAS) (21 studies, 29.2%). Eleven different PROs were used only once. Quality of evidence was graded as low given the percentage of studies that were observational or case series (68 of 72 studies, 94.4%)., Conclusion: Investigators have used many different PROs to assess outcomes for posterior malleolus fractures, the most common of which are the AOFAS, OMAS, and VAS. Future investigators should attempt to unify outcome reporting for these injuries., (© 2022. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Study Design: Retrospective cohort., Objective: Provide a comparison of surgical approach in the treatment of degenerative cervical myelopathy in patients with OPLL., Methods: A national database was queried to identify adult (≥18 years) patients with OPLL, who underwent at least a 2-level cervical decompression and fusion for cervical myelopathy from 2012-2014. A propensity-score-matching algorithm was employed to compare outcomes by surgical approach., Results: After propensity-score matching, 627 patients remained. An anterior approach was found to be an independent predictor for higher inpatient surgical complications(OR 5.9), which included dysphagia:14%[anterior]vs.1.1%[posterior] P -value < 0.001, wound hematoma:1.7%[anterior]vs.0%[posterior] P -value = 0.02, and dural tear:9.4%[anterior]vs.3.2%[posterior] P -value = 0.001. A posterior approach was an predictor for longer hospital length of stay by nearly 3 days(OR 3.4; 6.8 days[posterior]vs.4.0 days[anterior] P -value < 0.001). The reasons for readmission/reoperation did not vary by approach for 2-3-level fusions; however, for >3-level fusions, patients with an anterior approach more often had respiratory complications requiring mechanical ventilation( P -value = 0.038) and required revision fusion surgery( P -value = 0.015)., Conclusions: The national estimates for inpatient complications(25%), readmissions(9.9%), and reoperations(3.5%) are substantial after the surgical treatment of multi-level OPLL. An anterior approach resulted in significantly higher inpatient surgical complications, but this did not result in a longer hospital length of stay and the overall 90-day complication rates requiring readmission or reoperation was similar to those seen after a posterior approach. For patients requiring >3-level fusion, an anterior approach is associated with significantly higher risk for respiratory complications requiring mechanical ventilation and revision fusion surgery. Precise neurological complications and functional outcomes were not included in this database, and should be further assessed in future studies.

Study Design: Retrospective cohort study., Objective: Respiratory compromise (RC) is a rare but catastrophic complication of anterior cervical spine surgery (ACSS) commonly due to compressive fluid collections or generalized soft tissue swelling in the cervical spine. Established risk factors include operative duration, size of surgical exposure, myelopathy, among others. The purpose of this current study is to identify the incidence and clinical course of patients who develop RC, and identify independent predictors of RC in patients undergoing ACSS for cervical spondylosis., Methods: A large, prospectively-collected registry was used to identify patients undergoing ACSS for spondylosis. Patients with posterior cervical procedures were excluded. Baseline patient characteristics were compared using bivariate analysis, and multivariate analysis was employed to compare postoperative complications and identify independent predictors of RC., Results: 298 of 52,270 patients developed RC (incidence 0.57%). Patients who developed RC had high rates of 30-day mortality (11.7%) and morbidity (75.8%), with unplanned reoperation and pneumonia the most common. The most common reason for reoperations were hematoma evacuation and tracheostomy. Independent patient-specific factors predictive of RC included increasing patient age, male gender, comorbidities such as chronic cardiac and respiratory disease, preoperative myelopathy, prolonged operative duration, and 2-level ACCFs., Conclusion: This is among the largest cohorts of patients to develop RC after ACSS identified to-date and validates a range of independent predictors, many previously only described in case reports. These results are useful for taking preventive measures, identifying high risk patients for preoperative risk stratification, and for surgical co-management discussions with the anesthesiology team.

Study Design: Narrative Review., Objectives: The objective of this study was to compare publication status of clinical trials in adult spine surgery registered on ClinicalTrials.gov by funding source as well as to identify other trends in clinical trials in adult spine surgery., Methods: All prospective, comparative, therapeutic (intervention-based) trials of adult spinal disease that were registered on ClinicalTrials.gov with a start date of January 1, 2000 and completion date before December 17, 2018 were included. Primary outcome was publication status of published or unpublished. A bivariate analysis was used to compare publication status to funding source of industry vs non-industry., Results: Our search identified 107 clinical trials. The most common source of funding was industry (62 trials, 57.9% of total), followed by University funding (26 trials, 24.3%). The results of 76 trials (71.0%) were published, with industry-funded trials less likely to be published compared to non-industry-funded trials (62.9% compared to 82.2%, P = .03). Of the 31 unpublished studies, 13 did not report any results on ClinicalTrials.gov, and of those with reported results, none was a positive trial., Conclusions: Clinician researchers in adult spine surgery should be aware that industry-funded trials are less likely to go on to publication compared to non-industry-funded trials, and that negative trials are frequently not published. Future opportunities include improvement in result reporting and in publishing negative studies.

Objectives: This current systematic review sought to identify and evaluate all current research-based spine surgery applications of AI/ML in optimizing preoperative patient selection, as well as predicting and managing postoperative outcomes and complications., Methods: A comprehensive search of publications was conducted through the EMBASE, Medline, and PubMed databases using relevant keywords to maximize the sensitivity of the search. No limits were placed on level of evidence or timing of the study. Findings were reported according to the PRISMA guidelines., Results: After application of inclusion and exclusion criteria, 41 studies were included in this review. Bayesian networks had the highest average AUC (.80), and neural networks had the best accuracy (83.0%), sensitivity (81.5%), and specificity (71.8%). Preoperative planning/cost prediction models (.89,82.2%) and discharge/length of stay models (.80,78.0%) each reported significantly higher average AUC and accuracy compared to readmissions/reoperation prediction models (.67,70.2%) ( P < .001, P = .005, respectively). Model performance also significantly varied across postoperative management applications for average AUC and accuracy values ( P < .001, P < .027, respectively)., Conclusions: Generally, authors of the reviewed studies concluded that AI/ML offers a potentially beneficial tool for providers to optimize patient care and improve cost-efficiency. More specifically, AI/ML models performed best, on average, when optimizing preoperative patient selection and planning and predicting costs, hospital discharge, and length of stay. However, models were not as accurate in predicting postoperative complications, adverse events, and readmissions and reoperations. An understanding of AI/ML-based applications is becoming increasingly important, particularly in spine surgery, as the volume of reported literature, technology accessibility, and clinical applications continue to rapidly expand.

Study Design: Retrospective study., Objective: To examine the associated indications, procedures, and postoperative outcomes after revision ACDA., Methods: We utilized a national database to identify adult(≥18 years) patients who underwent either a primary ACDA or removal of ACDA over a 10-year period(2008-2017). An in-depth assessment of the reasons for revision surgery and the subsequent procedures performed after the removal of ACDA was done by using both Current Procedural Terminology(CPT) and International Statistical Classification of Diseases (ICD-9,10) coding., Results: From 2008 to 2017, a total of 3,350 elective, primary ACDA cases were performed. During this time, 69 patients had a revision surgery requiring the removal of ACDA. The most common reasons for revision surgery included cervical spondylosis(59.4%) and mechanical complications(27.5%). After removal of ACDA, common procedures performed included anterior cervical fusion with or without decompression(69.6%), combined anterior/posterior fusion/decompression (11.6%), and replacement of ACDA (7.2%). The indications for surgery did not vary significantly among the different procedures performed (p = 0.318). Patients requiring revision surgery for mechanical complications or those who underwent a combined surgical approach were at significantly higher risk for subsequent short-term complications (p<0.05)., Conclusion: Over a 10-year period, the rate of revision surgery for ACDA was low (2.1%). Nearly 90% of revision cases were due to either cervical spondylosis or mechanical complications. These indications for surgery did not vary significantly among the different procedures performed. These findings will be important during the shared-decision making process for patients undergoing primary or revision ACDA.

Background: The objective of this study was to compare inpatient mortality rates for patients with operatively treated closed femoral shaft fractures (AO/OTA 32 A-C) who received venous thromboembolism (VTE) prophylaxis with either low molecular weight heparin (LMWH) or unfractionated heparin., Methods: This was a retrospective cohort study of a national database of patients presenting to Level I through IV trauma centers in the United States. All patients ≥18 years of age who sustained an operatively treated closed femoral shaft fracture were included. The primary outcome of inpatient mortality was compared between two groups: those who received LMWH or unfractionated heparin for VTE prophylaxis. Secondary outcomes were complications including VTE and bleeding events. Groups were compared using a multivariate regression model., Results: There were 2058 patients included in the study. Patients who received VTE prophylaxis with LMWH had lower odds of inpatient mortality compared to patients who received VTE prophylaxis with unfractionated heparin (OR 0.19; 95% CI 0.05 to 0.68, p = 0.011)., Conclusions: VTE prophylaxis with LMWH is associated with lower inpatient mortality compared to VTE prophylaxis with unfractionated heparin for patients undergoing operative treatment of closed femoral shaft fractures. To our knowledge this is the first study to report these associations for a specific subset of orthopedic trauma patients., (© 2022.)

Background: The ulnar collateral ligament (UCL) of the elbow is subject to repetitive stress in overhead throwing athletes. This can lead to morphologic changes at the bony attachments of the UCL and hypertrophy of the sublime tubercle. The purpose of this case series is to describe the surgical details and clinical outcomes of a series of competitive baseball pitchers with hypertrophic sublime tubercles who underwent UCL reconstruction (UCLR)., Methods: All baseball pitchers who were treated for UCL injuries with significant hypertrophy of the sublime tubercle on preoperative imaging were included in the series. Clinical history, preoperative imaging, intraoperative findings during UCLR, and postoperative outcomes measured with the Conway scale were described., Results: Ten players (average age of 22.9 years [range 13-39]) were included (average follow-up 20.4 months [range 3-38 months]). Five patients also had symptoms of ulnar nerve compression, with 4 requiring transposition at the time of ULCR and 1 at 3 months postoperatively. Bony hypertrophy of the sublime tubercle was confirmed intraoperatively in all cases and excised before UCLR with the docking technique. Of the 7 patients with at least 12-month follow-up postoperatively, 6 had excellent outcomes, and 1 had a fair outcome., Conclusion: Although UCLR in the setting of hypertrophic sublime tubercle can be more complex than typical UCLR, excellent outcomes are achievable with preoperative recognition and surgical planning., (© 2022 The Author(s).)

Study Design: Retrospective cohort., Objective: To provide a national-level assessment of the short-term outcomes after spinal deformity surgery in pediatric patients with cerebral palsy., Methods: A national, prospectively collected database was queried to identify pediatric (≤18 years) patients with cerebral palsy, who underwent spinal fusion surgery from 2012 to 2017. Separate multivariate analyses were performed for the primary outcomes of interest including extended length of stay (>75th percentile, >8 days), and readmissions within 90 days after the index admission., Results: A total of 2856 patients were reviewed. The mean age ± standard deviation was 12.8 ± 2.9 years, and 49.4% of patients were female. The majority of patients underwent a posterior spinal fusion (97.0%) involving ≥8 levels (79.9%) at a teaching hospital (96.6%). Top medical complications (24.5%) included acute respiratory failure requiring mechanical ventilation (11.4%), paralytic ileus (8.2%), and urinary tract infections (4.6%). Top surgical complications (40.7%) included blood transfusion (35.6%), wound complication (4.9%), and mechanical complication (2.7%). The hospital cost for patients with a length of hospital stay >8 days ($113 669) was nearly double than that of those with a shorter length of stay ($68 411). The 90-day readmission rate was 17.6% (mean days to readmission: 30.2). The most common reason for readmission included wound dehiscence (21.1%), surgical site infection (19.1%), other infection (18.9%), dehydration (16.9%), feeding issues (14.5%), and acute respiratory failure (13.1%). Notable independent predictors for 90-day readmissions included preexisting pulmonary disease (odds ratio [OR] 1.5), obesity (OR 3.4), cachexia (OR 27), nonteaching hospital (OR 3.5), inpatient return to operating room (OR 1.9), and length of stay >8 days (OR 1.5)., Conclusions: Efforts focused on optimizing the perioperative pulmonary, hematological, and nutritional status as well as reducing wound complications appear to be the most important for improving clinical outcomes.

Study Design: Consecutively collected cases., Objective: To determine if a machine-learning (ML) program can accurately predict the postoperative thoracic kyphosis through the uninstrumented thoracic spine and pelvic compensation in patients who undergo fusion from the lower thoracic spine (T10 or T11) to the sacrum., Methods: From 2015 to 2019, a consecutive series of adult (≥18 years old) patients with adult spinal deformity underwent corrective spinal fusion from the lower thoracic spine (T10 or T11) to the sacrum. Deidentified data was processed by a ML system-based platform to predict the postoperative thoracic kyphosis (TK) and pelvic tilt (PT) for each patient. To validate the ML model, the postoperative TK (T4-T12, instrumented thoracic, and uninstrumented thoracic) and the pelvic tilt were compared against the predicted values., Results: A total of 20 adult patients with a minimum 6-month follow-up (mean: 22.4 ± 11.3 months) were included in this study. No significant differences were observed for TK (predicted 37.6° vs postoperative 38.3°, P = .847), uninstrumented TK (predicted 33.9° vs postoperative 29.8°, P = .188), and PT (predicted 23.4° vs postoperative 22.7°, P = .754). The predicted PT and the TK of the uninstrumented thoracic spine correlated well with postoperative values (uninstrumented TK: R 2 = 0.764, P < .001; PT: R 2 = 0.868, P < .001). The mean error with which kyphosis through the uninstrumented thoracic spine can be measured was 4.8° ± 4.0°. The mean error for predicting PT was 2.5° ± 1.7°., Conclusion: ML algorithms can accurately predict the spinopelvic compensation after spinal fusion from the lower thoracic spine to the sacrum. These findings suggest that surgeons may be able to leverage this technology to reduce the risk of proximal junctional kyphosis in this population.

Background: Private equity acquisition of medical specialty practices has increased in recent years. With the projected increase in the volume of elective, ambulatory orthopaedic procedures, especially in the outpatient setting, private equity firms are increasingly investing in orthopaedic practices. The purpose of this cross-sectional study was to report recent trends and variations in acquisitions of US orthopaedic practices by private equity firms and other institutional investors (venture capital firms, trusts, and large investment companies)., Methods: Acquisition data through January 1, 2020, were collected and analyzed using various financial databases, supplemented with publicly available information from financial news outlets, press releases, and financial analyst and industry reports. Disclosed financing data were also included, in addition to pertinent geographic information (state, city, and zip code) of the target practices., Results: Between 2004 and 2019, 41 orthopaedic practices and surgeon groups across 22 states were acquired by 34 private equity and other investment firms. A significant increase was observed in the number of acquisitions between 2017 and 2019, consisting of 70.7% of total transactions during the study period, with a statistically significant upward yearly trend (P = 0.002). The compound annual growth rate in acquisition volume was 29.2% during the study period. A disproportionate share of private equity acquisitions took place in the South, where more than half (51.2%) of the total transactions took place. Firms were markedly more likely to acquire or invest in practices located in major metropolitan areas (population more than 1 million) compared with those in mid-sized or rural areas (70.7%, 17.1%, 12.2%, respectively; P < 0.001)., Conclusions: Private equity acquisition of orthopaedic surgery practices has increased markedly in recent years. The effect of private equity acquisition on physician independence, practice management, and procedure reimbursement remains unclear and may be important to explore as practice management evolves., Level of Evidence: Prognostic Level III., (Copyright © 2022 by the American Academy of Orthopaedic Surgeons.)

Given the heightened focus on decreasing length of stay and readmissions following total joint arthroplasty, meticulous preoperative optimization has become increasingly important. The goal of this study was to evaluate the association between preoperative anemia and postoperative morbidity and mortality at 30 days. We used the National Surgical Quality Improvement Program database to identify patients who underwent primary total knee arthroplasty (TKA) between 2006 and 2016. Cohorts were defined based on preoperative hemoglobin and were evaluated for 30-day complications as well as 30-day readmission and non-home discharge. The survey of the National Surgical Quality Improvement Program database yielded 198,233 patients who underwent TKA between 2006 and 2016. Preoperative anemia was found to be a risk factor for all complications (4.73% vs 3.22%, P <.001) as well as non-home discharge (37.0% vs 24.2%, P <.001) and unplanned readmission (4.99% vs 3.14%, P <.001) using both bivariate analysis and multivariate analysis. Meticulous optimization of patients at risk for complications is critical in the era of bundled care and increased focus on rapid transition from inpatient to outpatient care. Preoperative anemia was associated with the total postoperative complication rate at 30 days following TKA as well as non-home discharge and unplanned readmission. Surgeons should attempt to identify patients with preoperative anemia and correct underlying low blood levels to help minimize the rate of postoperative complications. [ Orthopedics . 2022;45(2):e86-e90.].

Study Design: Retrospective National Database Study., Objective: Surgical intervention with spinal fusion is often indicated in cerebral palsy (CP) patients with progressive scoliosis. The purpose of this study was to utilize the National Readmission Database to determine the national estimates of complication rates, 90-day readmission rates, and costs associated with spinal fusion in adult patients with CP., Methods: The 2012-2015 NRD databases were queried for all adult (age ≥ 19 years) patients diagnosed with CP (ICD-9: 333.71, 343.0-4, and 343.8-9) undergoing spinal fusion (ICD-9: 81.00-08)., Results: 1166 adult patients with CP (42.7% female) underwent spinal fusion surgery between 2012 and 2015. 153 (13.1%) were readmitted within 90 days following the primary surgery, with a mean 33.8 ± 26.5 days. Mean hospital charge of the primary admission was $141,416 ± $157,359 and $167,081 ± $145,416 for the non-readmitted and readmitted patients, respectively (p = 0.06). The mean 90-day readmission charge was $72,479 ± $104,100. Most common complications with the primary admission included UTIs (no readmission vs. readmission: 7.6% vs. 4.8%; p = 0.18), respiratory (6.9% vs. 5.6%; p = 0.62), implant (3.8% vs. 6.0%; p = 0.21), and paralytic ileus (3.6% vs. 3.2%; p = 0.858). Multivariate analyses demonstrated the following as independent predictors for 90-day readmission: comorbid anemia (OR: 2.8; 95% CI: 1.6-4.9; p < 0.001), coagulopathy (2.9, 1.1-8.0, 0.037), perioperative blood transfusion (2.0, 1.1-3.8, 0.026), wound complication (6.4, 1.3-31.6, 0.023), and transfer to short-term hospital versus routine disposition (4.9, 1.0-23.3, 0.045)., Conclusion: Quality improvement efforts should be aimed at reducing rates of infection related complications as this was the most common reason for short-term complications and unplanned readmission following surgery., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Elbow flexion at late portions of the pitch has been associated with increased elbow varus torque, a kinetic surrogate associated with injury risk. Direct examinations of injury incidence with elbow flexion angles have not been conducted in professional pitchers., Purpose: To compare elbow and shoulder injury incidence among professional baseball players stratified by degree of elbow flexion at ball release (BR)., Study Design: Descriptive laboratory study., Methods: Professional pitchers (N = 314) were instructed to pitch between 8 and 12 fastballs while being evaluated using motion capture technology. Upper extremity injury incidence was recorded upon interview. Pitchers were subsequently subdivided into 3 groups based on increasing elbow flexion at BR. Analysis of variance was used to compare participant characteristics and kinematic and peak kinetic variables. An odds ratio (OR) was calculated to determine the risk of having a previous upper extremity injury based on the degree of elbow flexion at BR., Results: A total of 116 pitchers (132 documented injuries) had a previous upper extremity injury, with elbow injury (76 injuries; 57.6%) being the most common. Evaluation of kinetic values showed that pitchers with the smallest elbow flexion at BR had significantly less peak elbow flexion torque than did those with greatest elbow flexion at BR (3.8 ± 0.5 vs 4.1 ± 0.6 %weight × height; P = .003). Pitchers who demonstrated a greater than average degree of elbow flexion at BR when pitching were more likely to have a history of elbow injury (OR, 1.97; 95% CI, 1.14-3.40; P = .015) and olecranon spur formation or stress fracture (OR, 5.79; 95% CI, 1.25-26.85; P = .025)., Conclusion: Pitchers with greater elbow flexion at BR had significantly higher odds of previous injury of the elbow and olecranon. Increasing elbow flexion has been shown to place the medial elbow in a position to carry a greater amount of load, which may be exacerbated during the final moments of the pitching motion. Professional pitchers can consider decreasing elbow flexion at BR as a potential, modifiable risk factor for elbow injury, in particular for olecranon spur formation and fracture., Clinical Relevance: This study attempts to associate injury incidence with a modifiable, kinematic variable for an at-risk population.

Background: Fighting is often considered an essential part of professional hockey. Increased ticket sales, a means to self-regulate other dangerous gameplay, and helping teams win are a few of the reasons that fighting advocates provide for retaining fighting in the NHL. However, fighting trends have changed over the past 50 years. Given the recent data on concussions and player safety, an in-depth analysis of fighting is required to understand if fighting has a place in the future of the NHL., Methods: Seasonal statistical team data on NHL teams from the 1967 to 2019 seasons were collected and analyzed using publicly available databases. Specific outcome variables of interest related to fighting, penalties, the final team record for a given season, and final standing were recorded. The data were divided into subgroups according to "era of play" and before/after the implementation of the instigator rule. The trends in fighting, seasonal outcomes, and other minor penalties were assessed to determine the trends in fighting over the past 50 years, the relationship between fighting and winning, and the impact of the instigator rule., Results: Fights per game decreased significantly after the implementation of the instigator rule (0.71 to 0.51 fights per game, p  < 0.0001). There was no significant difference in fights per game when comparing Stanley Cup champions to nonplayoff teams in either the modern era (0.36 vs. 0.42, p  = 0.43) or the expansion era (0.45 vs. 0.51, p  = 0.49). Only two Stanley Cup champions (the Flyers 1974-1975 and the Ducks 2006-2007) led the league in fighting. A multivariate regression analysis comparing fights per game and points earned per season divided by the number of games played revealed a statistically significant inverse relationship (coefficient = -0.16, p  < 0.001)., Conclusion: Our analysis demonstrates that the Instigator rule achieved its intended effect to decrease the number of fights per game. In the current era of professional hockey, there is no compelling evidence that a team with more fights per game will achieve greater seasonal success. These results continue to cast doubt on the belief that fighting is a necessary strategy for winning games at the NHL level., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2022 Cole Morrissette et al.)

Study Design: Multicenter cohort., Objective: To compare the robot time/screw, radiation exposure, robot abandonment, screw accuracy, and 90-day outcomes between robot-assisted percutaneous and robot-assisted open approach for short lumbar fusion (1- and 2-level)., Summary of Background Data: There is conflicting literature on the superiority of robot-assisted minimally invasive spine surgery to open techniques. A large, multicenter study is needed to further elucidate the outcomes and complications between these two approaches., Methods: We included adult patients (≥18 yrs old) who underwent robot-assisted short lumbar fusion surgery from 2015 to 2019 at four independent institutions. A propensity score matching algorithm was employed to control for the potential selection bias between percutaneous and open surgery. The minimum follow-up was 90 days after the index surgery., Results: After propensity score matching, 310 patients remained. The mean (standard deviation) Charlson comorbidity index was 1.6 (1.5) and 53% of patients were female. The most common diagnoses included high-grade spondylolisthesis (grade >2) (48%), degenerative disc disease (22%), and spinal stenosis (25%), and the mean number of instrumented levels was 1.5(0.5). The operative time was longer in the open (198 min) versus the percutaneous group (167 min, P value = 0.007). However, the robot time/screw was similar between cohorts (P value > 0.05). The fluoroscopy time/ screw for percutaneous (14.4 s) was longer than the open group (10.1 s, P value = 0.021). The rates for screw exchange and robot abandonment were similar between groups (P value > 0.05). The estimated blood loss (open: 146 mL vs. percutaneous: 61.3 mL, P value < 0.001) and transfusion rate (open: 3.9% vs. percutaneous: 0%, P value = 0.013) were greater for the open group. The 90-day complication rate and mean length of stay were not different between cohorts (P value > 0.05)., Conclusion: Percutaneous robot-assisted spine surgery may increase radiation exposure, but can achieve a shorter operative time and lower risk for intraoperative blood loss for short-lumbar fusion. Percutaneous approaches do not appear to have an advantage for other short-term postoperative outcomes. Future multicenter studies on longer fusion surgeries and the inclusion of patient-reported outcomes are needed.Level of Evidence: 3., (Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc.)

Objective: Pedicle screw insertion for stabilization after lumbar fusion surgery is commonly performed by spine surgeons. With the advent of navigation technology, the accuracy of pedicle screw insertion has increased. Robotic guidance has revolutionized the placement of pedicle screws with 2 distinct radiographic registration methods, the scan-and-plan method and CT-to-fluoroscopy method. In this study, the authors aimed to compare the accuracy and safety of these methods., Methods: A retrospective chart review was conducted at 2 centers to obtain operative data for consecutive patients who underwent robot-assisted lumbar pedicle screw placement. The newest robotic platform (Mazor X Robotic System) was used in all cases. One center used the scan-and-plan registration method, and the other used CT-to-fluoroscopy for registration. Screw accuracy was determined by applying the Gertzbein-Robbins scale. Fluoroscopic exposure times were collected from radiology reports., Results: Overall, 268 patients underwent pedicle screw insertion, 126 patients with scan-and-plan registration and 142 with CT-to-fluoroscopy registration. In the scan-and-plan cohort, 450 screws were inserted across 266 spinal levels (mean 1.7 ± 1.1 screws/level), with 446 (99.1%) screws classified as Gertzbein-Robbins grade A (within the pedicle) and 4 (0.9%) as grade B (< 2-mm deviation). In the CT-to-fluoroscopy cohort, 574 screws were inserted across 280 lumbar spinal levels (mean 2.05 ± 1.7 screws/ level), with 563 (98.1%) grade A screws and 11 (1.9%) grade B (p = 0.17). The scan-and-plan cohort had nonsignificantly less fluoroscopic exposure per screw than the CT-to-fluoroscopy cohort (12 ± 13 seconds vs 11.1 ± 7 seconds, p = 0.3)., Conclusions: Both scan-and-plan registration and CT-to-fluoroscopy registration methods were safe, accurate, and had similar fluoroscopy time exposure overall.