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Study Design: In vitro analysis., Objective: The aim of this study was to assess the effect of three-dimensional (3D) printing of porous titanium on human mesenchymal stem cell (hMSC) adhesion, proliferation, and osteogenic differentiation., Summary of Background Data: A proprietary implant using three-dimensional porous titanium (3D-pTi) that mimics trabecu-lar bone structure, roughness, porosity, and modulus of elasticity was created (Ti-LIFE technology™, Spineart SA Switzerland). Such implants may possess osteoinductive properties augmenting fusion in addition to their structural advantages. However, the ability of 3D-pTi to affect in vitro cellular proliferation and osteogenic differentiation remains undefined., Methods: Disks of 3D-pTi with a porosity of 70% to 75% and pore size of 0.9 mm were produced using additive manufacturing technology. 2D Ti6Al4V (2D-Ti) and 2D polyetheretherketone (2D-PEEK) disks were prepared using standard manufacturing process. Tissue culture plastic (TCP) served as the control surface. All discs were characterized using 2D-micros-copy, scanning electron microscopy (SEM), and x-ray micro-computed tomography. Forty thousand hMSCs were seeded on the disks and TCP and cultured for 42 days. hMSC morphology was assessed using environmental SEM and confocal imaging following phalloidin staining. hMSC proliferation was evaluated using DNA fluorescent assay. hMSC differentiation was assessed using RT-qPCR for genes involved in hMSC osteogenic differentiation and biochemical assays were performed for alkaline phosphatase activity (ALP) and calcium content., Results: 3D-pTi lead to a higher cell number as compared to 2D-Ti and 2D-PEEK at D21, D28 and D42. ALP activity of hMSCs seeded into 3D-pTi scaffolds was as high as or higher than that of hMSCs seeded onto TCP controls over all time points and consistently higher than that of hMSCs seeded onto 2D-Ti scaffolds. However, when ALP activity was normalized to protein content, no statistical differences were found between all scaffolds tested and TCP controls., Conclusion: 3D-pTi provides a scaffold for bone formation that structurally mimics cancellous bone and improves hMSC adhesion and proliferation compared to 2D-Ti and PEEK., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective Database Study., Objective: Investigate utilization of bone morphogenetic protein (BMP-2) between 2004 and 2014., Summary of Background Data: The utilization, particularly off-label utilization, of BMP-2 has been controversial and debated in the literature. Given the concerns regarding cancer and potential complications, the risk benefit profile of BMP must be weighed with each surgical case. The debate regarding the costs and potential side effects of BMP-2 compared with autologous iliac crest bone harvest has continued., Methods: The National Inpatient Sample (NIS) database was queried for the use of BMP-2 (ICD-9-CM 84.52) between 2004 and 2014 across 44 states. The NIS database represents a 20% sample of discharges, weighted to provide national estimates. BMP-2 utilization rates in spine surgery fusion procedures were calculated as a fraction of the total number of thoracic, lumbar, and sacral spinal fusion surgeries performed each year., Results: Between 2004 and 2014, BMP-2 was utilized in 927,275 spinal fusion surgeries. In 2004, BMP-2 was utilized in 28.3% of all cases (N=48,613). The relative use of BMP-2 in spine fusion surgeries peaked in 2008 at 47.0% (N=112,180). Since then, it has continued to steadily decline with an endpoint of 23.6% of cases in 2014 (N=60,863)., Conclusions: Throughout the United States, the utilization of BMP-2 in thoracolumbar fusion surgeries increased from 28.3% to 47.0% between 2004 and 2008. However, from 2008 to 2014, the utilization of BMP-2 in thoracolumbar spine fusion surgeries decreased significantly from 47.0% to 23.4%. While this study provides information on the utilization of BMP-2 for the entire United States over an 11-year period, further research is needed to the determine the factors affecting these trends., Competing Interests: C.S. has stocks in Vertera Acquisition by Nuvasive and in Gilead. Z.S. has speaking/teaching arrangements with Medtronic and Stryker. A.J.P. has consulted for Globus Medical, United Healthcare and Medtronic. He has also received royalties from Globus Medical. V.M.A. had consulted for Medtronic, Stryker, Zimmer, Camber Spine, Spine Up, Johnson and Johnson and NuVasive. The remaining authors declare no conflict of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Background Context: Modernization of 3D printing has allowed for the production of porous titanium interbody cages (3D-pTi) which purportedly optimize implant characteristics and increase osseointegration; however, this remains largely unstudied in vivo., Purpose: To compare osseointegration of three-dimensional (3D) titanium cages without bone graft and Polyether-ether-ketone (PEEK) interbody cages with autologous iliac crest bone graft (AICBG)., Study Design: Animal study utilizing an ovine in vivo model of lumbar fusion., Methods: Interbody cages of PEEK or 3D-pTi supplied by Spineart SA (Geneva, Switzerland) were implanted in seven living sheep at L2-L3 and L4-L5, leaving the intervening disc space untreated. Both implant materials were used in each sheep and randomized to the aforementioned disc spaces. Computed tomography (CT) was obtained at 4 weeks and 8 weeks. MicroCT and histological sections were obtained to evaluate osseointegration., Results: MicroCT demonstrated osseous in-growth of native cancellous bone in the trabecular architecture of the 3D-pTi interbody cages and no interaction between the PEEK cages with the surrounding native bone. Qualitative histology revealed robust osseointegration in 3D-pTi implants and negligible osseointegration with localized fibrosis in PEEK implants. Evidence of intramembranous and endochondral ossification was apparent with the 3D-pTi cages. Quantitative histometric bone implant contact demonstrated significantly more contact in the 3D-pTi implants versus PEEK (p<.001); region of interest calculations also demonstrated significantly greater osseous and cartilaginous interdigitation at the implant-native bone interface with the 3D-pTi cages (p=.008 and p=.015, respectively)., Conclusions: 3D-pTi interbody cages without bone graft outperform PEEK interbody cages with AICBG in terms of osseointegration at 4 and 8 weeks postoperatively in an ovine lumbar fusion model., Clinical Significance: 3D-pTi interbody cages demonstrated early and robust osseointegration without any bone graft or additive osteoinductive agents. This may yield early stability in anterior lumbar arthrodesis and potentially bolster the rate of successful fusion. This could be of particular advantage in patients with spinal neoplasms needing post-ablative arthrodesis, where local autograft use would be ill advised., Competing Interests: Declarations of competing interests This study received grant funding through Spineart SA (Geneva, Switzerland). Spineart SA is the manufacturer of the tested implant devices in which this study sought to evaluate. The results from this manuscript were presented in abstract form at 35th Annual Meeting of the North American Spine Society on 1 September 2020. The manuscript has not been previously published nor is it under review in any other journal. No known or perceived conflicts of interest exist amongst any of the authors regarding the material presented within this manuscript, with the exception of Dr. Joseph Laratta, MD who reports the following in the interest of full disclosure: consulting roles with Stryker/K2M, NuVasive, 4Webb, Spineart, Evolution Spine, and Gerson Lehrman Group; receives royalties from Spineart, Evolution Spine, has intellectual property with Combination biologic and ICBG/BMAC system; receives grants from Medtronic, NuVasive, Stryker/K2M, Orthopaedic Science Research Foundation; receives travel and accommodations from American Institute of Minimally Invasive Surgery, NuVasive, Stryker/K2M, Spineart, Fisher Owen Fund; serves on the editorial board of Spine, Global Spine Journal, and Journal of Spine Surgery., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background Context: There are situations that require the replacement of pedicle screws. They are often exchanged when loose or broken or to accommodate a different sized rod or pedicle screw system. Traditionally, pedicle screws are replaced by up-sizing the core diameter until an interference fit is obtained. However, this method carries a risk of pedicle screw breach., Purpose: To determine if dual pitch screws, with cancellous pitch in the vertebral body and cortical pitch throughout the pedicle, allows for in-line screw revision without upsizing screw diameter., Study Design: Cadaveric biomechanical Study PATIENT SAMPLE: Not applicable OUTCOME MEASURES: Not applicable METHODS: Pedicle screws were tested in the lumbar vertebrae from eleven cadavers. Standard pitch 5.5 mm screws were inserted and loaded using a "break-in" protocol. Screws were removed and replaced with one of four screw types: 5.5 mm Standard Pitch, 5.5 mm Dual Pitch, 6.0 mm Standard Pitch, or 6.0 mm Dual Pitch. Failure testing was done using a stepwise increasing cyclic loading protocol for 100 cycles at each increasing load level. The loading consisted of a combined axial and bending load simulating the load seen by the most inferior screw., Results: Failure was consistent, with the tip of the screw displacing inferiorly into the vertebral body while simultaneously pulling out. Failure strength was lowest in the 5.5mm Standard (135.8±29.4N) followed by 6.0mm Standard (141.8±38.6N), 5.5mm Dual (158.1±53.8N), and 6.0mm Dual (173.6±52.1N, p=.023). There was no difference in the failure strength between the 5.5mm Dual and 6.0mm Standard. Lumbar level (p=.701) and donor spine (p=.062) were not associated with failure strength., Conclusions: After pedicle screw removal, screws with a larger core diameter or with a dual pitch have similar failure strengths. Dual pitch screws may allow for in-line revision of screws without upsizing screw diameter, minimizing the risk of pedicle breach or fracture., Clinical Significance: Dual pitch screws, with cancellous pitch in the vertebral body and cortical pitch through the pedicle, allows for in-line revision of pedicle screws without upsizing screw diameter; reducing the risk of pedicle breach or fracture when exchanging screws., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Study Design: Multicenter retrospective study., Objective: Flexion-extension radiographs are frequently used to assess motion in patients with degenerative spondylolisthesis. However, they expose patients to additional radiation and increase cost. The aim of this study is to determine if flexion-extension radiographs provide additional information not seen on upright neutral radiographs and supine magnetic resonance imaging (MRI) that may guide surgical decision making., Summary of Background Data: Supine MRI and upright neutral radiographs are routinely performed in patients with degenerative spondylolisthesis. It is unclear whether additional flexion-extension views play a significant role in surgical planning for this patient population., Methods: From the Quality Outcomes Database, patients who had surgery for grade 1 degenerative spondylolisthesis were identified. Magnitude of slip on pre-op supine MRI, upright neutral, flexion, and extension radiographs were measured. Additional motion was defined as 3 mm or more slip difference between radiographs. For the purpose of this analysis, patients with a slip of 7 mm or more on upright neutral radiographs were assumed to require a fusion., Results: A total of 191 patients were identified. Mean age was 61.6 years (114 females, 60%). Only 31 patients (16%) had additional motion on flexion-extension views not seen on upright neutral x-rays versus supine MRI. Of these 31 patients, 19 had slips less than 7 mm on upright x-ray, generating equipoise for fusion., Conclusion: Flexion-extension radiographs may play a limited role in management of degenerative spondylolisthesis. The subset of patients for which flexion-extension views were most likely to provide value were patients with smaller slips (<7 mm) with no evidence of motion on standing radiographs versus MRI. In 90% of spondylolisthesis cases, information used for surgical planning may be ascertained by comparing motion between supine MRI and upright lateral radiographs.Level of Evidence: 3., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Recent work has shed light on the potential benefits of cannabinoids for multimodal pain control following orthopedic procedures. The objective of this review was to summarize the available evidence of analgesic and opioid-sparing effects cannabinoids have in orthopedic surgery and identify adverse events associated with their use., Methods: A systematic review of the literature using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines including PubMed, EMBASE, MEDLINE, PsycINFO, and Google Scholar was performed to include all primary, therapeutic studies published on the use of cannabis, and cannabis-derived products in orthopedic surgery., Results: The literature review returned 4292 citations. Thirteen publications were found to meet inclusion criteria. Four randomized controlled trials were evaluated while the remaining studies were of quasi-experimental design., Conclusion: Research on cannabinoids in orthopedic surgery is mostly of a quasi-experimental nature and is mainly derived from studies where orthopedics was not the primary focus. The overall results demonstrate potential usefulness of cannabinoids as adjunctive analgesics and in mitigating opioid use. However, the current evidence is far from convincing. There is a need to produce rigorous evidence with well-designed randomized controlled trials specific to orthopedic surgery to further establish these effects.

Background: The opioid epidemic is at epic proportions currently in the United States. Exposure to opioids for surgery and subsequent postoperative pain management is a known risk factor for opioid dependence. In addition, opioids can have a negative impact on multiple aspects including clinical outcomes, length of hospital stay, and overall cost of care. Thus, the greatest effort to reduce perioperative opioid use is necessary and a multimodal pain control (MMPC) has been gaining popularity. However, its efficacy in spine surgery is not well known. We aimed to evaluate the efficacy of a MMPC protocol in patients undergoing lumbar single-level anterior lumbar interbody fusion (ALIF)., Methods: This is a retrospective comparative study. From a prospective, single-surgeon, surgical database, consecutive patients undergoing single-level ALIF with or without subsequent posterior fusion for degenerative lumbar conditions were identified before and after initiation of the MMPC protocol. The MMPC protocol consisted of a preoperative oral regimen of cyclobenzaprine (10 mg), gabapentin (600 mg), acetaminophen (1 g), and methadone (10 mg). Postoperatively they received a bilateral transverse abdominis plane block with 0.5% Ropivacaine prior to extubation. We compared in-hospital opioid consumption between the MMPC and non-MMPC cohorts as well as baseline demographic, the length of hospital stay, cost, and rate of postoperative ileus. Opioid consumption was calculated and normalized to the morphine milligram equivalents (MMEs)., Results: In total, 68 patients in the MMPC cohort and 39 in the non-MMPC cohort were identified. There was no difference in baseline demographics including sex, body mass index, smoking status, or preoperative opioid use between the two groups. Although there was no difference in the MMEs on the day of surgery (58.5 vs. 66.9, P=0.387), cumulative MMEs each day after surgery was significantly lower in the MMPC cohort, with final cumulative MMEs being reduced by 62% (120.2 vs. 314.8, P<0.001). There was no difference in postoperative ileus, length of stay, and hospital costs., Conclusions: The use of a MMPC protocol in patients undergoing single-level ALIF for degenerative conditions reduced opioid consumption starting on the first day after surgery, resulting in a cumulative reduction of 62%., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/jss-20-629). Dr. JLG reports personal fees from Acuity, personal fees from Medtronic, personal fees from DePuy, personal fees from Alphatec, from Stryker, from Acuity, from K2M, from NuVasive, personal fees from Pfizer, outside the submitted work; Dr. CHC 3rd reports personal fees from Alphatec, personal fees from Medtronic, personal fees from NuVasive, personal fees from Alphatec, personal fees from Medtronic, personal fees from Titan, personal fees from SRS Committee, personal fees from NASS Committee, outside the submitted work; Dr. MD reports personal fees from Medtronic, personal fees from NuVasive, outside the submitted work; Dr. RKO 2nd reports personal fees from Medtronic, personal fees from NuVasive, grants from Pfizer, grants from Texas Scottish Rite Hospital, grants from Alan L. & Jacqueline B. Stuart Spine Research, grants from Cerapedics, grants from SRS, grants from Medtronic, grants from OREF, grants from ISSG, outside the submitted work; Dr. JRD 2nd reports personal fees from Medtronic, personal fees from DePuy, other from Federation Of Spine Association, other from SRS, personal fees from Pfizer, outside the submitted work; Dr. SDG reports personal fees from Medtronic, outside the submitted work; Dr. LYC reports personal fees from AO spine, personal fees from Center for Spine Surgery and Research of the University of Southern Denmark, personal fees from University of Louisville Institutional Review Board, grants from Scoliosis Research Society Research, grants from Orthopedic Educational Research Fund, grants from Integra, grants from Pfizer, personal fees from Pfizer, outside the submitted work. The other authors have no conflicts of interest to declare., (2020 Journal of Spine Surgery. All rights reserved.)

Objective: Unexpected nonhome discharge causes additional costs in the current reimbursement models, especially to the payor. Nonhome discharge is also related to longer length of hospital stay and therefore higher healthcare costs to society. With increasing demand for spine surgery, it is important to minimize costs by streamlining discharges and reducing length of hospital stay. Identifying factors associated with nonhome discharge can be useful for early intervention for discharge planning. The authors aimed to identify the drivers of nonhome discharge in patients undergoing 1- or 2-level instrumented lumbar fusion., Methods: The electronic medical records from a single-center hospital administrative database were analyzed for consecutive patients who underwent 1- to 2-level instrumented lumbar fusion for degenerative lumbar conditions during the period from 2016 to 2018. Discharge disposition was determined as home or nonhome. A logistic regression analysis was used to determine associations between nonhome discharge and age, sex, body mass index (BMI), race, American Society of Anesthesiologists grade, smoking status, marital status, insurance type, residence in an underserved zip code, and operative factors., Results: A total of 1502 patients were included. The majority (81%) were discharged home. Factors associated with a nonhome discharge were older age, higher BMI, living in an underserved zip code, not being married, being on government insurance, and having more levels fused. Patients discharged to a nonhome facility had longer lengths of hospital stay (5.6 vs 3.0 days, p < 0.001) and significantly increased hospital costs ($21,204 vs $17,518, p < 0.001)., Conclusions: Increased age, greater BMI, residence in an underserved zip code, not being married, and government insurance are drivers for discharge to a nonhome facility after a 1- to 2-level instrumented lumbar fusion. Early identification and intervention for these patients, even before admission, may decrease the length of hospital stay and medical costs.

Background: The utilization of the S2 Alar-Iliac (S2AI) screw provides an optimal method of spinopelvic fixation. The free-hand placement of these screws obviates the use of intra-operative fluoroscopy and relies heavily on sacropelvic anatomy; variations of this anatomy could alter the ideal screw trajectory. The S2AI corridor is near several neurovascular structures, thus an accurate trajectory is critical. The reported angles of trajectory vary within the literature and a paucity of data exists on how patient morphometry influences ideal screw trajectory. We sought to examine the relationship between ideal screw trajectory and pelvic parameters., Methods: The records of 99 consecutive patients with degenerative thoracolumbar pathology were reviewed and pelvic parameters including sacral slope, pelvic tilt, and pelvic incidence were measured with preoperative standing radiographs. Using 3-dimensional computed tomography (CT) reconstructions, an ideal S2AI trajectory was defined and anteroposterior (horizontal) and cephalocaudal (sagittal) angles were recorded., Results: Pelvic tilt was found to have a moderate inverse correlation with cephalocaudal screw trajectory ( r =-0.467, p-value=0.006). Pelvic incidence and sacral slope had weaker correlations with cephalocaudal screw angle. In subgroup analysis, patients with high pelvic tilt (>20°) had a significantly lower cephalocaudal screw trajectory (24.9 ± 3.7° versus 29.8 ± 2.8°, p-value=<0.001) compared to those with a normal pelvic tilt ( ≤ 20°)., Conclusions: This study found an inverse relationship between pelvic tilt and cephalocaudal S2AI screw trajectory. Therefore, the sagittal angle of insertion becomes increasingly more perpendicular to the floor (less caudally orientated) as pelvic tilt increases in reference to a patient positioned prone on an operating table parallel to the floor. This may bolster safety and efficacy when utilizing the free-hand technique for placement of the S2AI screw as it allows the surgeon to plan a more ideal trajectory by accounting for pelvic parameters., Competing Interests: None., (© 2020 The Authors. Published by Elsevier Ltd on behalf of North American Spine Society.)

Study Design: Literature review., Objectives: Posterior cervical interfacet cages are an alternative to lateral mass fixation in patients undergoing cervical spine surgery. Recently, a percutaneous, tissue-sparing system for interfacet cage placement has been developed, however, there is limited clinical evidence supporting its widespread use. The aim was to review studies published on this system for patient reported outcomes, radiographic outcomes, intraoperative outcomes, and complications., Methods: Four electronic databases (PubMed, EMBASE, Scopus, and MEDLINE) were queried for original published studies that evaluated the percutaneous, tissue-sparing technique for posterior cervical fusion with interfacet cage placement. All studies reporting on open techniques and purely biomechanical studies were excluded., Results: The extensive literature search returned 7852 studies. After systematic review, a total of 7 studies met inclusion criteria. Studies were independently classified as retrospective or prospective cohort studies and each assessed by the GRADE criteria. Patient reported outcomes, radiographic outcomes, intraoperative outcomes, and complications were extracted from each study and presented., Conclusions: Tissue-sparing, posterior cervical fusion with interfacet cages may be considered a safe and effective surgical intervention in patients failing conservative management for cervical spondylotic disease. However, the quality of evidence in the literature is lacking, and controlled, comparative studies are needed for definitive assessment., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article. Dr Joseph Laratta reports personal fees for consultancy from Spineart, Evolution Spine, and Gerson Lehrman Group, royalties from Spineart and Evolution Spine, intellectual property with Combination Biologic and ICBG/BMAC system, grants from Medtronic, NuVasive, Orthopaedic Science Research Foundation, Orthopaedic Research and Education Foundation, personal fees for travel expenses/meeting accommodations from American Institute of Minimally Invasive Surgery (AIMIS), NuVasive, Stryker, K2M, and Fisher Owen Fund, and is on the editorial board for Spine, Global Spine Journal, and Journal of Spine Surgery. Dr William Smith reports personal fee for consultancy from NuVasive, Spineology, Pediguard, Providence, and Ortho Bio Design, grants from MDT, NuVasive, Providence, and Spineology, ownership interest in NuVasive, Pediguard, and SpineSmith, royalty from NuVasive and Spineology, and is on the speakers’ bureau for NuVasive and Pediguard., (© The Author(s) 2019.)

Although primary tumors of the spine and neural elements are rare, metastatic disease to the spine is quite common. Traditionally, surgical treatment for spinal tumor patients involves open decompression with or without stabilization. The single-position minimally invasive (MIS) lateral approach, which has been recently described over the recent decade, allows simultaneous access to the anterior and posterior columns with the patient positioned in the lateral decubitus position. Herein, we review the application of single-position MIS lateral surgery for the treatment of spinal neoplasm. The aim was to review the evolution, operative technique, outcomes, and complications associated with MIS lateral approaches for spinal tumors. The history of spinal tumor diagnosis and management are reviewed and discussed as well as the author's experience and literature regarding spinal tumor treatment outcome and surgical complications, with particular attention to single-position, MIS lateral approaches. In addition, the author's surgical technique is outlined in detail for thoracic, thoracolumbar and lumbar tumors. Furthermore, there are specific indications and complications associated with the surgical treatment of spinal tumors, and the MIS, single-position lateral approach, when applied appropriately, allows for concurrent access to the anterior and posterior column while mitigating the complications associated with traditional, open posterior-based approaches. In the treatment of spinal neoplasms, the goals of surgery are dictated by a number of tumor-specific and patient-specific factors. Therefore, operative treatment of tumors in the future may be a consolidation of historical surgical techniques and MIS, single-position lateral approaches. Regardless, multidisciplinary management is imperative for the individualized treatment of the patient and optimization of outcome., Competing Interests: Conflicts of Interest: Dr. Laratta reports personal fees from Stryker/K2m, NuVasive, Spineart, Evolution Spine, American Institute of Minimally Invasive Surgery, and Gerson Lehrman Group; grants from Medtronic, NuVasive, Orthopaedic Science Research Foundation, and Fisher-Owen Fund; and Editorial Board of the following: Spine, Global Spine Journal, and Journal of Spine Surgery. Dr. Smith reports personal fees from NuVasive, Spineology, Pediguard, Providence, and Ortho Bio Design; as well as grants from NuVasive, Providence, Spineology, and Medtronic. The other authors have no conflicts of interest to declare., (2020 Journal of Spine Surgery. All rights reserved.)

Background: Cortical bone trajectory (CBT) screws have been recently described as a method of lumbosacral fixation. These screws are typically inserted under fluoroscopic guidance with a medial-to-lateral trajectory in the axial plane and a caudal-to-cephalad trajectory in the sagittal plane. In an effort to reduce surgeon radiation exposure and improve accuracy, CBT screws may be inserted under navigation with intraoperative cone beam computed tomography (CT). However, the accuracy of CBT screw placement under intraoperative navigation has yet to be assessed in the literature. The purpose of the study was to evaluate the accuracy of CBT screw placement using intraoperative cone beam CT navigation., Methods: One hundred and thirty-four consecutive patients who underwent CBT fixation with 618 screws under intraoperative navigation were analyzed from May 2016 through May 2018. Screws were placed by one of three senior spine surgeons using the Medtronic O-Arm Stealth Navigation. Screw position and accuracy were assessed on intraoperative and postoperative CT scans using 2D and 3D reconstructions with VitreaCore software., Results: The majority of surgeries were primary cases (73.1%). The mean age at the time of surgery was 61.5±10.0 years and the majority of patients were female (61.2%). Most patients underwent surgery for a diagnosis of degenerative spondylolisthesis (47.8%) followed by mechanical collapse with foraminal stenosis (22.4%). Ten violations of the vertebral cortex were noted with an average breach distance of 1.0±0.7 mm. Three breaches were lateral (0.5%) and seven were medial (1.1%). The overall navigated screw accuracy rate was 98.3%. The accuracy to within 1 mm of error was 99.2%. There were no intra-operative neurologic, vascular, or visceral complications related to the placement of the CBT screws., Conclusions: CBT screw fixation under an intraoperative cone beam CT navigated insertion technique is safe and reliable. Despite five breaches greater than 1mm, there were no complications related to the placement of the CBT screws in this series., Competing Interests: Conflicts of Interest: JL Laratta—consulting (Spineart, Evolution Spine, Gerson Lehrman Group), royalties (Spineart, Evolution Spine), Intellectual Property (Combination Biologic, ICBG/BMAC system), grants (Medtronic, Nuvasive, Orthopaedic Science Research Foundation, Orthopaedic Research and Education Foundation), editorial board (Spine, Global Spine Journal, Journal of Spine Surgery). JL Gum—consulting (Medtronic, Depuy, Alphatec, Stryker, Acuity, K2M, NuVasive, Pacmed), royalties (Acuity), editorial board (American Journal of Orthopedics), grants (Fischer Owen Fund), research support (Integra, Intellirod Spine Inc., Pfizer, International Spine Study Group Foundation, NuVasive). M Djurasovic—consulting (Medtronic), royalties (Medtronic, NuVasive), research support (NuVasive, Pfizer, Norton Healthcare), speaker (Medtronic). CH Crawford—consulting (Alphatec, Medtronic), speaker (Norton Hospital), research funding (Norton Hospital). The other authors howe no conflicts of interest to declare., (2019 Journal of Spine Surgery. All rights reserved.)

Background: Adult spinal deformity (ASD) is a prevalent condition in individuals over the age of 65; leading to impaired standing balance and abnormal gait patterns. This functional impairment may be due to the fixed sagittal or coronal malalignment; associated spinal stenosis or deconditioning. The Berg balance scale (BBS) was developed to measure balance by assessing the performance of functional tasks. The purpose of this study is to determine if BBS is a useful metric for evaluating functional status in ASD patients., Methods: ASD patients who required fusion from the thoracic spine to the pelvis from 2014 to 2016 were enrolled and asked to complete the BBS prior to and six months after surgery. BBS were obtained by a certified physical therapist. Standard demographic; radiographic and surgical data were collected. The Oswestry disability index (ODI), EuroQOL-5D and numeric rating scales (0 to 10) for back and leg pain were assessed at baseline and post-intervention., Results: Of 21 patients enrolled; 19 completed pre- and post-surgery BBS. The mean age was 59.8±13.3 years with 14 females. There was a statistically significant improvement in all outcome scores and radiographic parameters after surgery; but no difference in BBS. Only one patient had a BBS score low enough to be considered a medium fall risk. There was no difference in the pre-op BBS scores in the four patients that had revision surgery compared to those that did not., Conclusions: In this small pilot study; BBS did not appear to be associated with measures of clinical and radiographic improvement in ASD patients. The test was also potentially problematic in that it has a ceiling effect and required significant time with a trained physical therapist for administration. Continued effort to identify a viable measure of balance dysfunction in ASD patients is warranted., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare., (2019 Journal of Spine Surgery. All rights reserved.)

A survey was administered to a random sampling of the American Academy of Orthopaedic Surgeons (AAOS) members to determine the rate at which recently trained orthopedic surgeons switch their first job and to identify factors affecting the job selection process. There were 351 (21%) respondents. Respondents considered practice location (41%), practice type (28%), and family proximity (23%) as most important while research opportunity (54%) and signing bonus (33%) were considered least important in their first job. Half of the respondents (51%) left their first job before the completion of their fifth year; most left for financial reasons (34%) or because the practice was not as advertised (31%). Many (53%) stated they had minimal training in selecting their first job and most (88%) felt inadequately prepared for the business side of orthopedics. Further studies are needed to evaluate the high rate of initial post-training job attrition to decrease the personal and societal costs of this phenomenon., Competing Interests: The authors have declared financial relationships, which are detailed in the next section., (Copyright © 2019, Laratta et al.)

Image guidance (IG) and robotics systems are becoming more widespread in their utilization and can be invaluable intraoperative adjuncts during spine surgery. Both are highly reliant upon stereotaxy and either pre- or intraoperative radiographic imaging. While user-operated IG systems have been commercially available longer and subsequently are more widely utilized across centers, robotics systems provide unique theoretical advantages over freehand and IG techniques for placing instrumentation within the spine. While there is a growing plethora of data showing that IG and robotic systems decrease the incidence of malpositioned screws, less is known about their impact on clinical outcomes. Both robotics and IG may be of particular value in cases of substantial deformity or complex anatomy. Indications for the use of these systems continue to expand with an increasing body of literature justifying their use in not only guiding thoracolumbar pedicle screw placement, but also in cases of cervical and pelvic instrumentation as well as spinal tumor resection. Both techniques also offer the potential benefit of reducing occupational exposures to ionizing radiation for the operating room staff, the surgeon, and the patient. As the use of IG and robotics in spine surgery continues to expand, these systems' value in improving surgical accuracy and clinical outcomes must be weighed against concerns over cost and workflow. As newer systems incorporating both real-time IG and robotics become more utilized, further research is necessary to better elucidate situations where these systems may be particularly beneficial in spine surgery., (Copyright © 2019 by the Congress of Neurological Surgeons.)

Background: Objective of this study is to evaluate demographics, risk factors, and incidence of instrumentation related complications (IRC) in spinal surgeries from 2009-2012. The Scoliosis Research Society (SRS) morbidity and mortality (M&M) database has tremendous value in orthopaedic surgery. SRS gathers surgeon-reported complications, including instrumentation failure, visual complications, neurological deficits, infections, and death. Limited literature exists on the incidence of perioperative instrumentation complications in deformity surgery. We utilized the SRS database to evaluate demographics, risk factors, and incidence of IRC in spinal surgeries from 2009-2012., Methods: The SRS M&M database was queried for IRC in patients undergoing surgery for scoliosis, spondylolisthesis, and kyphosis from 2009-2012. Demographics, comorbidities, diagnoses, curve magnitude, and intraoperative characteristics were analyzed. Intraoperative characteristics included surgical approach, performance of fusion or osteotomy, operative times, blood loss, instrumentation used, and documented instrumentation complication., Results: A total of 167,972 patients were identified, including 311 IRC. The overall IRC rate was 0.19% (18.5 per 10,000 patients), which decreased significantly from 2009-2012 (0.37% vs. 0.19%, P<0.001). The mean age of patients with IRC was 38.5±25.5 years. Most common comorbidities included hypertension (23.5%), pulmonary disease (13.5%), diabetes (10.6%), smoking (8.7%), and vascular disease (7.1%). IRC occurred in 206 (66.2%) patients with scoliosis, 58 (18.6%) with spondylolisthesis, and 45 (14.5%) with kyphosis. Compared to patients with spondylolisthesis, patients with kyphosis (0.27% vs. 0.11%, P<0.001) and scoliosis (0.21% vs. 0.11%, P<0.001), experienced significantly more IRC. IRC included implant failure (23.3%), migration (28.3%), and malpositioned implants (48.6%). New perioperative neurologic deficits were reported in 146 (46.9%) patients, and 84 (27%) of these implants were removed., Conclusions: IRC occur in approximately 18.5 per 10,000 deformity patients, with a rate significantly higher in patients with kyphosis. The potentially avoidable occurrence of implant malpositioning represents nearly 50% of these complications. Closer attention to posterior bony anatomy, improved intraoperative imaging with utilization of navigation or robotic guidance may decrease these complications., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare.

Objective To define the critical elements of common procedures in arthroscopic surgery. Methods A survey was administered to surgeons associated with the American Orthopaedic Society for Sports Medicine (AOSSM) to determine the critical elements for four common arthroscopic procedures: anterior cruciate ligament (ACL) reconstruction, knee arthroscopy with meniscal debridement or repair, rotator cuff repair (RCR), and capsulorrhaphy for anterior glenohumeral instability (Bankart repair). Respondents were asked which steps necessitated their direct supervision. The level of experience and practice demographics were also recorded. Results For all applicable procedures, patient positioning and closure were not considered critical steps. Establishing arthroscopic portals was critical for all procedures, except knee arthroscopy. Diagnostic arthroscopy was only critical in ACL reconstruction. Private practice surgeons considered every step of these common procedures to be critical elements. Less experienced surgeons were more likely to regard certain aspects of a procedure critical. Surgeons with >15 years of experience considered diagnostic arthroscopy critical to all procedures, whereas those with <15 years of experience did not. Unlike surgeons with a resident as first assist, surgeons with a physician assistant (PA) or nurse practitioner (NP) found every step of each procedure to be critical except closure and positioning. Conclusion Across all procedures, only patient positioning and closure were consistently regarded as non-critical elements. There were significant differences in responses according to experience and practice setting. Future research is necessary to determine the implications of these findings and guide the definition of the "critical portions" of surgery., Competing Interests: The authors have declared that no competing interests exist.

Background: Tethered drains are a complication of drain usage and may result in unintentional retained broken drains, as well as anxiety and uncertainty for the surgeon and the patient. To date, no study has examined the optimal approach for management and removal of tethered drains., Methods: The study design sought to identify suture size, mechanism of drain fixation (through versus around), points of constriction (one versus multiple) and the efficacy of weighted traction as potential sources of tethered drains by means of four study arms. (1) Arm one compared drains sutured through the tubing versus a tight closure of the surrounding fascia, which were then subjected to weighted suspension. (2) Arm two compared drains sutured into the fascia using eight each of 4-0, 2-0 and 0 vicryl and then subject to manual traction. (3) Arm three compared drains sutured to the fascia through the tubing versus local tissue incarceration followed by manual traction. (4) Lastly, group four examined drains tethered at two distinct points after which they were subject to manual traction., Results: Our results showed a 25% drain retention rate when manual traction was applied to 0 vicryl and 2-0 vicryl suture. In contrast, there were no instances of drain retention when suture was closed with 4-0 vicryl. When evaluating for multiple points of fixation, drains tethered in two locations were retained in 87.5% of trials versus drains with a single tether point (25%) representing a statistical significance (P = 0.041). There was no difference in rates of drain retention when pierced through the tubing versus incarcerated in local fascia. Only one of the 16 drains was successfully removed by weighted suspension (8.3%). Attempts at manual traction following weighted suspension resulted in a 50% drain retention rate which was higher than the rates of immediate manual traction (18.8%)., Conclusion: Our results found that manual traction is a reasonable first line approach to address drains tethered by all methods and suture sizes. The use of weighted traction for the management of tethered drains is less effective than manual traction and may result in more retained drain fragments., Level of Evidence: Level IV.

Study Design: Retrospective matched cohort analysis., Objective: To compare the accuracy of S2 alar-iliac (S2AI) screw placement by robotic guidance versus free hand technique., Summary of Background Data: Spinopelvic fixation utilizing S2AI screws provides optimal fixation across the lumbosacral junction allowing for solid fusion, especially in long segment fusion constructs. Traditionally, S2AI screw placement has required fluoroscopic guidance for accurate screw placement. Herein, we present the first series comparing a free hand and robotic-guided technique for S2AI screw placement., Methods: Sixty-eight consecutive patients who underwent S2AI screw placement by either a free hand or robotic technique between 2015 and 2016 were reviewed. Propensity score-matching was utilized to control for preoperative characteristic imbalances. Screw position and accuracy were evaluated using three-dimensional manipulation of computed tomography scan reconstructions from intraoperative O-arm imaging., Results: A total of 51 patients (105 screws) were matched, 28 (59 screws) in the free hand group (FHG) and 23 (46 screws) in the robot group (RG). The mean age in the FHG and RG were 57.9 ± 14.6 years and 61.6 ± 12.0 years (P = 0.342), respectively. The average caudal angle in the sagittal plane was significantly larger in the RG (31.0 ± 10.0° vs. 25.7 ± 8.8°, P = 0.005). There was no difference between the FHG and RG in the horizontal angle, measured in the axial plane using the posterior superior iliac spine (PSIS) as a reference (41.1 ± 8.1° vs. 42.8 ± 6.6°, P = 0.225), or the S2AI to S1 screw angle (9.4 ± 7.0° vs. 11.3 ± 9.9°, P = 0.256), respectively. There was no difference in the overall accuracy between FHG and RG (94.9% vs. 97.8%, P = 0.630). Additionally, there were no significant intraoperative neurovascular or visceral complications associated with S2AI screw placement., Conclusion: Free hand and robotic-guided S2AI screw placement both prove to be safe, accurate, and reliable techniques for achieving spinopelvic fixation., Level of Evidence: 3.

Background Context: Limited or no data exist evaluating risk factors associated with prolonged opioid use following cervical arthrodesis., Purpose: The objectives of this study were to assess trends in postoperative narcotic use among preoperative opioid users (OUs) versus non-opioid users (NOUs) and to identify factors associated with postoperative narcotic use at 1 year following cervical arthrodesis., Study Design/setting: This is a retrospective observational study., Patient Sample: The patient sample included 17,391 patients (OU: 52.4%) registered in the Humana Inc claims dataset who underwent anterior cervical fusion (ACF) or posterior cervical fusion (PCF) between 2007 and 2015., Outcome Measures: Prolonged opioid usage was defined as narcotic prescription filling at 1 year following cervical arthrodesis., Methods: Based on preoperative opioid use, patients were identified as an OU (history of narcotic prescription filled within 3 months before surgery) or a NOU (no preoperative prescription). Rates of opioid use were evaluated preoperatively for OU and trended for 1 year postoperatively for both OU and NOU. Multivariable regression techniques investigated factors associated with the use of narcotics at 1 year following ACF and PCF. Based on the model findings, a web-based interactive app was developed to estimate 1-year postoperative risk of using narcotics following cervical arthrodesis (http://neuro-risk.com/opiod-use/ or https://www.neurosurgerycost.com/opioid/opioid&#95;use)., Results: Overall, 87.4% of the patients (n=15,204) underwent ACF, whereas 12.6% (n=2187) underwent PCF. At 1 month following surgery, 47.7% of NOUs and 82% of OUs had a filled opioid prescription. Rates of prescription opioids declined significantly to 7.8% in NOUs versus 50.5% in OUs at 3 months, but plateaued at the 6- to 12-month postoperative period (NOU: 5.7%-6.7%, OU: 44.9%-46.9%). At 1 year, significantly higher narcotic prescription filling rates were observed in OUs compared with NOUs (45.3% vs. 6.3%, p<.001). Preoperative opioid use was a significant driver of 1-year narcotic use following ACF (odds ratio [OR]: 7.02, p<.001) and PCF (OR: 6.98, p<.001), along with younger age (≤50 years), history of drug dependence, and lower back pain., Conclusions: Over 50% of the patients used opioids before cervical arthrodesis. Postoperative opioid use fell dramatically during the first 3 months in NOU, but nearly half of the preoperative OUs will remain on narcotics at 1 year postoperatively. Our findings serve as a baseline in identifying patients at risk of chronic use and encourage discontinuation of opioids before cervical spine surgery., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Study Design: Retrospective review of prospectively collected data., Objective: Analyze the Scoliosis Research Society (SRS) Morbidity & Mortality (M&M) database to assess the incidence and characteristics related to postoperative surgical site infection (SSI) after spinal deformity surgery., Summary of Background Data: Infections involving spinal instrumentation are associated with greater rates of disability. Rates of postoperative SSI after spinal deformity surgery range from 1.9% to 4.4%. Postoperative SSI rates of 4.2% for adult kyphosis, 2.1% for adult spondylolisthesis, and 3.7% for adult scoliosis have been reported., Methods: The SRS M&M database was evaluated to define patient demographics, perioperative factors, and infection characteristics of spinal deformity patients with postoperative spine infections after deformity surgery in 2012., Results: Of the 47,755 procedures reported to the SRS in 2012, there were 578 (1.2%) diagnosed SSIs. Infection rates for patients with kyphosis were significantly higher compared with patients with scoliosis (2.4% vs. 1.1%, p < .0001) or spondylolisthesis (2.4% vs. 1.1%, p < .0001). Spinal fusions were performed in 86.3% of patients, 75.1% of which were performed posteriorly. Osteotomies were performed in 30.1% of patients. Deep infections below the fascia accounted for 68.0% of infections. Methicillin-sensitive (41.9%) and methicillin-resistant (17.0%) Staphylococcus aureus were the most commonly isolated pathogens, whereas gram-negative bacteria accounted for 25.4% of cases. Long-term antibiotic suppression was required in 18.9% of patients, and overall complications from antibiotics occurred in 4.5% of patients. Operative treatment was required in 81.8% of SSI cases., Conclusion: SSIs occur in 1.2% of spine deformity patients, with a rate significantly higher in patients with kyphosis. Approximately 25% of these infections are secondary to gram-negative species. Antibiotic complications occur in 4.5% of patients being treated for SSI. Despite advancements in surgical technique and infection prophylaxis, postoperative SSI remains one of the most common complications in spinal deformity surgery., Level of Evidence: Level III., (Copyright © 2018 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)

Objective: The S2-alar-iliac (S2AI) screw is an increasingly popular method for spinopelvic fixation. The technique of freehand S2AI screw placement has been recently described. The purpose of this study was to demonstrate, through a CT imaging study of patients with spinal deformity, that screw trajectories based on the posterior superior iliac spine (PSIS) and sacral laminar slope result in reliable freehand S2AI trajectories that traverse safely above the sciatic notch., Methods: Fifty consecutive patients (age ≥ 18 years) who underwent primary spinal deformity surgery were included in the study. Simulated S2AI screw trajectories were analyzed with 3D visualization software. The cephalocaudal coordinate for the starting point was 15 mm cephalad to the PSIS. The mediolateral coordinate for the starting point was in line with the lateral border of the dorsal foramina. The cephalocaudal screw trajectory was perpendicular to the sacral laminar slope. Screw trajectories, lengths, and distance above the sciatic notch were measured., Results: The mean sagittal screw angle (cephalocaudal angulation) was 44.0° ± 8.4° and the mean transverse angle (mediolateral angulation) was 37.3° ± 4.3°. The mean starting point was 5.9 ± 5.8 mm distal to the caudal border of the S1 foramen. The mean screw length was 99.9 ± 18.6 mm. Screw trajectories were on average 8.5 ± 4.3 mm above the sciatic notch. A total of 97 of 100 screws were placed above the sciatic notch. In patients with transitional lumbosacral anatomy, the starting point on the lumbarized/sacralized side was 3.4 mm higher than on the contralateral unaffected side., Conclusions: The PSIS and sacral laminar slope are two important anatomical landmarks for freehand S2AI screw placement.

Study Design: A retrospective review of the Scoliosis Research Society (SRS) morbidity and mortality (M&M) database., Objective: The aim of this study was to investigate visual related complications in spinal deformity patients undergoing spine surgery., Summary of Background Data: The SRS compiles surgeon-reported complications into an M&M database, tracking postoperative complications including visual loss, neurological deficits, infections, and death. Limited literature exists on postoperative visual complications, a rare but devastating complication following spine surgery., Methods: We utilized the SRS M&M database to determine demographics, perioperative risk factors, and prognosis for visual related complications in spinal deformity patients undergoing corrective spine surgery from 2009 to 2012., Results: A total of 167,972 spinal deformity patients from 2009 to 2012 were identified with a visual acuity complication (VAC) rate of 0.01%, or 12.5 per 100,000 patients. VAC rates for patients with kyphosis were significantly higher than patients with scoliosis (0.049% vs. 0.010%, P = 0.002) and spondylolisthesis (0.049% vs. 0.005%, P = 0.001). Postoperative visual loss rates significantly decreased from 2010 to 2012 (0.022% vs. 0.004%, P = 0.029). Twenty-one patients identified with VACs had a mean age of 34.8 ± 24.3 years. Two (9.5%) patients had preoperative vision changes, two (9.5%) were diabetic, two (9.5%) had vascular disease, one (4.8%) had a history of thromboembolic disease, and five (23.8%) had hypertension. Extent of VAC was bilateral-partial in four (19.0%), bilateral-total in five (23.8%), unilateral-partial in eight (38.1%), and unilateral-total in three (14.3%) patients. Four (19.0%) patients developed anterior ischemic optic neuropathy, four (19.0%) had posterior ischemic optic neuropathy (PION), five (23.8%) had central retinal artery occlusion, and five (23.8%) developed cortical blindness (CB). Greater than 50% of the VACs occurred on, or before, the first postoperative day. Ten (47.6%) patients recovered complete vision and four (19.0%) improved. All patients with CB and 50% with posterior ischemic optic neuropathy experienced complete resolution., Conclusion: VACs occur in approximately 12.5 per 100,000 deformity patients, with a rate five times higher in patients with kyphosis. More than 50% of these complications occur within 24 hours postoperatively. Nearly half of these complications resolve completely, and another 19% improve postoperatively., Level of Evidence: 4.

Background: Anterior cervical discectomy and fusion (ACDF) for cervical degenerative disease is an accepted treatment for symptomatic cervical radiculopathy and myelopathy. One- and two-level fusions are much more common and more widely studied. Outcomes and revision rates for three- and four-level ACDF have not been well described. The purpose of this study is to report on clinical outcomes and revision rates following multilevel ACDF., Methods: Patients who underwent three- or four-level anterior cervical discectomy with plate fixation between 2006 and 2011 from a single-center multi-surgeon practice for symptomatic cervical degenerative disease were identified. Improvements in neck disability index (NDI), neck and arm pain scores two years after surgery and revision rates were analyzed., Results: Forty-six patients with a mean age of 55.9 years were included in the analysis. Twenty-one (46%) were male, 10 (22%) were smokers. Forty-one (89%) underwent three-level fusion and 5 (11%) underwent four-level fusion. NDI improved from 34.46 at baseline to 25.47 at 2 years. Neck pain improved from 7.04 at baseline to 3.95 and arm pain improved from 6.24 to 3.09 at 2 year follow up. Sixteen patients (35%) returned to surgery within 2 years with 11 of these patients (24%) returning for non-union. The average number of days to revision surgery was 750.6±570.3 days., Conclusions: Patients undergoing three- and four-level ACDF for multilevel cervical disease demonstrate substantial improvement in outcomes. However, the two-year revision rate is relatively high at 35% with the majority of these patients returning due to non-union., Competing Interests: Conflicts of Interest: Dr. JL Laratta reports consulting for Evolution Spine and research support from Orthopaedic Science Research Foundation and Norton Healthcare. Dr. LY Carreon reports consulting for AO Spine, trips/travel for Center for Spine Surgery and Research of the University of Southern Denmark and University of Louisville Institutional Review Board, and research support from the Scoliosis Research Society, Orthopedic Educational Research Fund, Integra and Pfizer. Dr. R. Kirk Owens reports consulting for Medtronic, Nuvasive and Alphatec, trips/travel from Depuy Synthes, Medtronic, and Nuvasive, research support from Pfizer and Integra, and fellowship support from Norton Healthcare. The other authors have no conflicts of interest to declare.

Achieving fixation and fusion across the lumbosacral junction has been a challenge for spinal deformity surgeons ever since the development of instrumentation. The S2 alar-iliac (S2AI) trajectory has been introduced as a method of pelvic fixation to decrease strain on S1 screws. The S2AI screws differ in several ways from traditional iliac screws. The trajectory of these screws helps avoid the use of offset connectors due to the screws alignment with the proximal pedicle screw instrumentation. Current literature shows that S2AI screws are effective with low complication rates, but the path of these screws is intimately associated with major neural and vascular structures. Use of robotic guidance to obtain the correct trajectory has been shown to be both safe and effective in obtaining proper trajectory of S2AI screws with over 95% accuracy. Herein, we report on the technical considerations and radiographic outcomes surrounding robotic and freehand insertion of S2AI screws., Competing Interests: Conflicts of Interest: JL Laratta, MD—Research funding: Orthopaedic Science Research Foundation, Norton Healthcare; Consulting: Evolution Spine; Review Board: Spine, Global Spine Journal. JL Gum, MD—Consultant: Medtronic, Dupuy, Alphatec, Stryker, Acuity, K2M, Nuvasive, Pacmed (1/15); Royalties: Acuity; Honorarium: MiMedx (11/14), Pacira Pharmaceuticals; Advisory/Editorial Board: American Journal of Orthopedics; Grants: Fischer Owen Fund—Travel Funds (12/31/16); Journal Reviewer: The Spine Journal, American Journal of Orthopedics; Research Support: Integra, Intellirod Spine Inc., Pfizer, International Spine Study Group Foundation—Funds to institution only, NuVasive—Database support only; Norton Healthcare: Research Funding. LG Lenke, MD—Board Membership OREF and GSO: Unpaid position; Personal Fees: Consultancy—Dupuy Synthes Spine, K2M, Medtronic—monies donated to a charitable foundation; Personal Fees: Expert Testimony—Fox Rothschild, LLP; Grants: AO Spine; Scoliosis Research Society; DePuy Synthes Spine; Setting Scoliosis Straight Foundation; EOS—monies paid to institution; Royalties: Medtronic; Quality Medical Publishing; Travel accommodations/meeting expenses: AO Spine; Broadwater, Seattle Science Foundation; Scoliosis Research Society; The Spinal Research Foundation—Reimbursement for airfare/hotel only; Fellowship Grant: AO Spine North America—institutional support for fellowship; Grant: Philanthropic Research funding—Fox Family Foundation; Evans Family. RA Lehman, MD—Grant: PRORP (Department of Defense Peer Reviewed Orthopaedic Research Program—paid directly to organization; Personal Fees/Financial Support: Dupuy Synthes Spine—Honoraria for Speakers Bureau, Travel paid for any speaking arrangements; Stryker—Honoraria for Speakers Bureau, Travel paid for any speaking arrangements; Medtronic—Consulting fees, Honoraria for Speakers Bureau, Travel paid for any speaking arrangements. The other authors have no conflicts of interest to declare.

Background: To identify temporal changes to the demographics and utilization of intraoperative neuromonitoring (IONM) throughout the United States (U.S.)., Methods: The National Inpatient Sample (NIS) database was queried for IONM of central and peripheral nervous electrical activity (ICD-9-CM 00.94) between 2008 and 2014. The NIS database represents a 20% sample of discharges from U.S. Hospitals, weighted to provide national estimates. Demographic and economic data were obtained which included the annual number of surgeries, age, sex, insurance type, location, and frequency of routine discharge., Results: The estimated use of IONM of central and peripheral nervous electrical activity increased 296%, from 31,762 cases in 2008 to 125,835 cases in 2014. Based on payer type, privately insured patients (45.0%), rather than Medicare (36.8%) or Medicaid patients (9.2%), were more likely to undergo IONM during spinal procedures. When stratifying by median income for patient zip code, there was a substantial difference in the rates of IONM between low (19.9%) and high-income groups (78.1%). IONM was significantly more likely to be utilized at urban teaching hospitals (72.9%) rather than nonteaching hospitals (25.0%) or rural centers (2.2%)., Conclusions: Over the last decade, there has been a massive increase of 296% in utilization of IONM during spine surgery. This is likely due to its proven benefit in reducing neurologic morbidity in spinal deformity surgery, while introducing minimal additional risk. While IONM may improve patient care, it is still rather isolated to teaching hospitals and patients from higher income zip codes., Competing Interests: Conflicts of Interest: Dr. Ronald A. Lehman reports grants from PRORP (Department of Defense Peer Reviewed Orthopaedic Research Program), personal fees and non-financial support from DePuy Synthes Spine, personal fees and non-financial support from Stryker, and personal fees and non-financial support from Medtronic outside the submitted work. Dr. Lawrence G. Lenke reports Board Membership from OREF and GSO, personal fees from Consultancy—DePuy Synthes Spine, K2M, Medtronic, personal fees from Expert Testimony—Fox Rothschild, LLP, grants from AO Spine, Scoliosis Research Society, DePuy Synthes Spine, Setting Scoliosis Straight Foundation, EOS, Royalties from Medtronic and Quality Medical Publishing, patent from Medtronic, personal fees from Travel accommodations/meeting expenses—AO Spine, Broadwater, Seattle Science Foundation, Scoliosis Research Society, The Spinal Research Foundation, grants from Fellowship Grant—AO Spine, North America, and grants from Philanthropic research funding. The other authors have no conflicts of interest to declare.

Study Design: Retrospective database study., Objectives: Analysis of economic and demographic data concerning interspinous device (ID) placement throughout the United States to improve value-based care and health care utilization., Methods: The National Inpatient Sample (NIS) database was queried for patients who underwent insertion of an interspinous process spinal stabilization device (ICD-9-CM 84.80) between 2008 and 2014 across 44 states. Demographic and economic data were obtained which included the annual number of surgeries, age, sex, insurance type, location, and frequency of routine discharge. The NIS database represents a 20% sample of discharges from US hospitals, which is weighted to provide national estimates., Results: There was a 73% decrease in ID implanted from 2008 to 2014. The mean cost associated with insertion of the device increased 28% from $13 653 in 2008 to $17 515 in 2014. The mean length of stay (LOS) increased from 1.8 to 2.4 days. Patients aged 45 to 64 years increased from 14.1% to 34.3% while patients aged 65 to 84 years decreased from 74.4% to 60.6%. By region, 34% of ID placement occurred in the South followed by 19.7% that occured in the Northeast. When stratifying by median income for patient zip code, the procedure was performed more in cities designated as higher rather than lower income areas (74.2% and 19.5%, respectively)., Conclusions: Throughout the United States, there was a progressive decline in the insertion of interspinous spacers by 73% over the study period. The total costs for the procedure increased by 28% while the aggregate national charges decreased by 55.6% between 2008 and 2014., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Dr Ronald A. Lehman Jr reports grants from PRORP (Department of Defense Peer Reviewed Orthopaedic Research Program), personal fees and nonfinancial support from DePuy Synthes Spine, personal fees and nonfinancial support from Stryker, personal fees and nonfinancial support from Medtronics outside the submitted work. Dr Lawrence Lenke reports unpaid positions from Board Membership OREF and GSO, personal fees from Consultancy–DePuy Synthes Spine, K2M, Medtronic, personal fees from Expert Testimony–Fox Rothschild, LLP, grants from AO Spine; Scoliosis Research Society; DePuy Synthes Spine; Setting Scoliosis Straight Foundation; EOS, Royalties from Patents–Medtronic, personal fees from Travel accommodations/meeting expenses–AOSpine, Broadwater, Seattle Science Foundation, Scoliosis Research Society, The Spinal Research Foundation, grants from Fellowship Grant–AOSpine, North America, grants from Philanthropic research funding outside the submitted work. No other authors report potential conflicts of interest.

Study Design: Survey., Objective: To define the critical elements of common spine surgeries., Summary of Background Data: Despite significant relevance to the field of spine surgery, the term "critical element" of surgery has not been clearly defined. Every surgical procedure involves numerous steps, each with its own potential for complications and harm to the patient. Despite its crucial role in surgical training, billing, and the ethicality of concurrent surgery, the term "critical element" of surgery has not been defined., Methods: A survey was administered to surgeons associated with AO Spine North America and the Society for Minimally Invasive Spine Surgery to determine the critical elements for four common spine procedures: open lumbar laminectomy and fusion, microdiscectomy, anterior cervical discectomy and fusion (ACDF), and posterior cervical laminectomy and fusion. Respondents were asked which steps necessitated their direct supervision. Surgical subspecialty, level of experience, and practice demographics were also recorded., Results: For all applicable procedures, decompression, instrumentation, and fusion were designated as critical elements. Patient positioning and fascial closure were not. Radiographic localization was considered critical for all procedures, except posterior cervical laminectomy and fusion. Exposure was not considered critical for any procedures, except ACDF. Certain substeps of decompression in ACDF and open lumbar laminectomy and fusion were not considered critical. Orthopaedic surgeons considered exposure and fusion in ACDF procedures to be critical whereas neurosurgeons did not. Surgeons operating in private practice considered every step of these common procedures to be critical elements., Conclusion: Decompression, instrumentation, and fusion were considered critical elements of common spine surgeries. There were significant differences in responses according to surgical specialty and practice setting. Future research is necessary to determine the implications of these findings and guide the definition of the "critical portions" of surgery., Level of Evidence: 1.

Study Design: Biological augmentation spinal arthrodesis trial in athymic rats., Objective: To assess the efficacy of tissue-engineered bone to promote L4-L5 intertransverse process fusion in an athymic rat model., Summary of Background Data: Each year in the United States, over 400,000 spinal fusion surgeries are performed requiring bone graft. The current gold standard for posterolateral lumbar fusion is autogenous iliac crest bone graft (ICBG), but the harvesting of ICBG is associated with increased operative time and significant complications. This being the case, an alternative cost-effective bone graft source is needed., Methods: Bovine bone cores were sterilized and decellularized for scaffold production. Human adipose derived mesenchymal stem cells (ADSC) were obtained and verified by tridifferentiation testing and seeded onto dried scaffolds. The seeded cores were cultured for 5 weeks in culture medium designed to mimic endochondral ossification and produce hypertrophic chondrocytes. Single-level intertransverse process fusions were performed at the L4-L5 level of 31 athymic rats. Fifteen rats were implanted with the hypertrophic chondrocyte seeded scaffold and 16 had scaffold alone. Half of the study rats were sacrificed at 3 weeks and the other half at 6 weeks. Spinal fusion was assessed using 2D and 3D micro computed tomography (μCT) analysis and tissue histology., Results: At 3 weeks, none of the tissue engineered rats had partial or complete fusion, whereas 62.5% of the decellularized rats fused and another 12.5% had partial fusions (P = 0.013). At 6 weeks, none of the tissue engineered rats fused and 50% had partial fusions, whereas 87.5% of the decellularized rats fused (P = 0.002)., Conclusion: Tissue engineered bone composed of hypertrophic chondrocytes inhibits posterolateral fusion in an athymic rat model and therefore does not represent a promising cost-effective bone graft substitute., Level of Evidence: N/A.

Study Design: Retrospective review of high-dose tranexamic acid (TXA) use in consecutive patients., Objective: To determine the safety profile of a high-dose TXA protocol in complex adult spinal deformity patients., Summary of Background Data: Adult spinal deformity (ASD) surgery may involve significant amounts of blood loss, especially when various osteotomy techniques are used. Antifibrinolytic agents such as TXA have been used to reduce intraoperative blood loss. However, there is no universally accepted dosing protocol for its use during complex ASD surgery., Methods: Consecutive patients undergoing spinal deformity correction over a 14-month period at a single institution were identified. Inclusion criteria were adults (age ≥18 years) who underwent posterior spinal fusion of at least 5 levels and use of our standard TXA protocol of 50 mg/kg intravenous loading dose followed by a 5-mg/kg/h infusion until skin closure. Patient demographics, estimated blood loss (EBL), operative time, transfusion rates, complications, and other procedure-specific information were recorded., Results: A total of 100 adult patients were included. All operative procedures were performed by the senior surgeon. The mean age was 47.3 years, and 71% of patients were female. Average body mass index was 24.9. The average fusion length was 14 levels; 33/100 patients had fusion constructs of 17 levels or more. Pedicle subtraction osteotomy was performed in 9 patients and vertebral column resections were performed in 14 patients. There were 45/100 patients who had a primary procedure, whereas the rest were revisions. Mean EBL was 1,336 mL (98 mL/level, 31% estimated blood volume). There were three thromboembolic complications, including one pulmonary embolism and two deep vein thromboses (DVTs), which were all treated successfully with anticoagulation. There were no cases of myocardial infarction, seizure, stroke, or acute renal failure., Conclusions: This is the first study to demonstrate the use of high-dose TXA in a complex ASD population. Larger prospective studies are needed to assess the efficacy and safety of high-dose TXA in ASD., Level of Evidence: Level IV, therapeutic., (Copyright © 2017 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)

Study Design: Case series., Objectives: To determine the safety and feasibility of S2 alar-iliac (S2AI) screw placement under robotic guidance., Summary of Background Data: Similar to standard iliac fixation, S2AI screws aid in achieving fixation across the sacropelvic junction and decreasing S1 screw strain. Fortunately, the S2AI technique minimizes prominent instrumentation and the need for offset connectors to the fusion construct. Herein, we present an analysis of the largest series of robotic-guided S2AI screws in the literature without any significant author conflicts of interest with the robotics industry., Methods: Twenty-three consecutive patients who underwent spinopelvic fixation with 46 S2AI screws under robotic guidance were analyzed from 2015 to 2016. Screws were placed by two senior spine surgeons, along with various fellow or resident surgical assistants, using a proprietary robotic guidance system (Renaissance; Mazor Robotics Ltd., Caesara, Israel). Screw position and accuracy was assessed on intraoperative CT O-arm scans and analyzed using three-dimensional interactive viewing and manipulation of the images., Results: The average caudal angle in the sagittal plane was 31.0° ± 10.0°. The average horizontal angle in the axial plane using the posterior superior iliac spine as a reference was 42.8° ± 6.6°. The average S1 screw to S2AI screw angle was 11.3° ± 9.9°. Two violations of the iliac cortex were noted, with an average breach distance of 7.9 ± 4.8 mm. One breach was posterior (2.2%) and one was anterior (2.2%). The overall robotic S2AI screw accuracy rate was 95.7%. There were no intraoperative neurologic, vascular, or visceral complications related to the placement of the S2AI screws., Conclusions: Spinopelvic fixation achieved using a bone-mounted miniature robotic-guided S2AI screw insertion technique is safe and reliable. Despite two breaches, no complications related to the placement of the S2AI screws occurred in this series., Level of Evidence: Level IV, therapeutic., (Copyright © 2017 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)

Background: Controversy exists over the ability of various lumbar interbody fusion techniques to realign global and regional balance and their effect on patient outcomes. This is a retrospective cohort study to compare thirty-day postoperative outcomes between anterior and posterior interbody fusion techniques within a large national database., Methods: A retrospective cohort study utilizing the National Surgical Quality Improvement Program (NSQIP) database included 2,372 (29.9%) single-level anterior/direct lateral interbody fusions (ALIF/DLIF) and 5,563 (70.1%) single-level posterior/transforaminal lateral interbody fusions (PLIF/TLIF) between 2013 and 2014. Emergent cases, fracture cases, and preoperative compromised wounds were not analyzed. Primary thirty-day outcomes included mortality, return to operating room, readmission, length of stay, and other major complications. Minor outcomes included urinary tract infection, superficial incisional site infection, and perioperative blood transfusion within 72 hours., Results: ALIF/DLIF was performed more for degenerative lumbar disc disease (31.0% vs. 13.9%, P<0.001), whereas PLIF/TLIF was utilized more for spondylolisthesis (19.1% vs. 24.4%, P<0.001). Thirty-day mortality was significantly higher with ALIF/DLIF (0.3% vs. 0.1%, P=0.021) in the univariate analysis and persisted in the multivariate analysis (OR =12.8; 95% CI, 1.37-119.6; P=0.025). Significantly more PLIF/TLIF patients required blood transfusions within 72 hours of surgery (9.6% vs. 7.6%, P=0.005). This difference did not persist in the multivariate analysis after controlling for covariates. Elevated ASA physical status classification, age >60, prior bleeding disorder, and preoperative anemia were significantly associated with blood transfusion requirement. More deep venous thrombosis occurred (DVT) with ALIF/DLIF compared to PLIF/TLIF (1.0% vs. 0.6%, P=0.025), which persisted in the multivariate analysis (OR =2.03; 95% CI, 1.13-3.65; P=0.017)., Conclusions: Although numerous techniques can be utilized in the treatment approach to various lumbar pathologies, anterior approaches have an increased risk of developing a perioperative DVT and early mortality. Transfusion risk is more strongly associated with elevated American Society of Anesthesiologists (ASA) class, increased age, preoperative anemia, and patients with bleeding disorders., Competing Interests: Conflicts of Interest: Dr. Ronald Lehman Jr reports grants from PRORP (Department of Defense Peer Reviewed Orthopaedic Research Program), personal fees and non-financial support from DePuy Synthes Spine, personal fees and non-financial support from Stryker, and personal fees and non-financial support from Medtronic outside the submitted work. The other authors have no conflicts of interest to declare.

The prevalence of patients with adult spinal deformity (ASD) has been reported as high as 68%. ASD often leads to significant pain and disability. Recent emphasis has been placed on sagittal plane balance and restoring normal sagittal alignment with regards to the three dimensional deformity of ASD. Optimal sagittal alignment has been known to increase spinal biomechanical efficiency, reduce energy expenditure by maintaining a stable posture with improved load absorption, influence better bony union, and help to decelerate adjacent segment deterioration. Increasingly positive sagittal imbalance has been shown to correlate with poor functional outcome and poor self-image along with poor psychological function. Compensatory mechanisms attempt to maintain sagittal balance through pelvic rotation, alterations in lumbar lordosis as well as knee and ankle flexion at the cost of increased energy expenditure. Restoring normal spinopelvic alignment is paramount to the treatment of complex spinal deformity with sagittal imbalance. Posterior osteotomies including posterior column osteotomies, pedicle subtraction osteotomies, and posterior vertebral column resection, as well anterior column support are well known to improve sagittal alignment. Understanding of whole spinal alignment and dynamics of spinopelvic alignment is essential to restore sagittal balance while minimizing the risk of developing sagittal decompensation after surgical intervention.

Background: Spinopelvic fixation is an integral part of achieving solid fusion across the lumbosacral junction, especially in deformity procedures requiring substantial correction or long-segment constructs. Traditional S2-alar-iliac (S2AI) screw-placement techniques utilize fluoroscopy, increasing operative time and radiation exposure to the patient and surgeon. We describe a novel free-hand technique for S2AI screw placement in patients with adult spinal deformity., Methods: We reviewed the records of 45 consecutive patients who underwent spinopelvic fixation performed with use of S2AI screws by the senior surgeon and various fellows or residents over a 12-month period (2015 to 2016). In each case, the S2AI screws were placed utilizing a free-hand technique without fluoroscopic or image guidance. Screw position and accuracy were assessed by intraoperative O-arm imaging and analyzed using 3-dimensional interactive manipulation of computed tomography images., Results: A total of 100 screws were placed, 51 by the senior surgeon and 49 by trainees. The mean patient age was 57.4 ± 12.7 years at the time of surgery; 37 (82.2%) of the patients were female. Preoperative diagnoses included adult idiopathic scoliosis (n = 19), adult degenerative scoliosis (n = 15), flatback syndrome (n = 2), fixed sagittal imbalance (n = 6), and distal junctional kyphosis (n = 3). Five (5%) of the screws were placed with moderate to severe cortical breaches, all of which perforated the pelvis posteriorly, with no clinically notable neurovascular or visceral complications. The breach rate did not differ significantly between the senior surgeon and trainees., Conclusions: The free-hand technique for S2AI screw placement, when performed in a standardized manner, was demonstrated to be safe and reliable in constructs requiring spinopelvic fixation. The accuracy of screw placement relies on visible and palpable anatomic landmarks that obviate the need for intraoperative fluoroscopy or image guidance, potentially reducing operative time and radiation exposure., Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Study Design: Systematic review., Objectives: Degenerative disc disease and spondylosis resulting in radiculopathy and retrodiscal myelopathy are among the most frequently encountered cervical spinal disorders. Traditionally, anterior cervical discectomy and fusion (ACDF) has successfully achieved neural decompression and restored intradiscal height in these conditions. Unfortunately, nonunion and iatrogenic adjacent segment pathology associated with fusion procedures in the cervical spine has led to an interest in motion-preserving procedures. Cervical disc arthroplasty (CDA) was developed in hopes of preserving cervical biomechanics while mitigating the complications associated with ACDF. Through a systematic review of both published and ongoing studies on single- and multilevel CDA, and hybrid surgeries, we aim to provide evidence for their safety and efficacy in the treatment of various cervical pathologies., Methods: A systematic search of several large databases, including Cochrane Central, PubMed, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry was conducted to identify published studies and ongoing clinical trials on CDA and hybrid surgery., Results: Among the relevant studies reviewed, 3 were randomized controlled trials, 2 systematic reviews, as well as multiple prospective case series, biomechanical studies, and meta-analyses., Conclusion: Over the past decade, multiple high-quality studies have shown that single-level CDA can offer equivalent clinical outcomes with a reduction in secondary procedures and total cost when compared to ACDF. However, more recently there has been an increasing prevalence of 2-level CDA and hybrid surgery. Although the data regarding these multilevel procedures is less robust, it appears that they may be as effective as their single-level counterparts., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Dr Riew reports personal fees from AOSpine, various universities for visiting professorships, personal fees from Biomet, Medtronic, other support from Expanding Orthopaedics, personal fees from Expert Testimony, grants from Medtronic, other support from Amedica, Benvenue, Nexgen Spine, Paradigm Spine, Spinal Kinetics, Spineology, Vertiflex, and outside the submitted work.

Study Design: Literature review., Objective: The aim of this study was to provide an overview of the available intraoperative monitoring techniques and the evidence around their efficacy in vertebral column resection., Methods: The history of neuromonitoring and evolution of the modalities are reviewed and discussed. The authors' specific surgical techniques and preferred methods are outlined in detail. In addition, the authors' experience and the literature regarding vertebral column resection and surgical mitigation of neurologic alarms are discussed at length., Results: Risk factors for signal changes have been identified, including preoperative neurologic deficit, severe kyphosis, increased curve magnitude, and significant cord shortening. Even though no evidence-based treatment algorithm exist for signal changes, strategies are discussed that can help prevent alarms and address them appropriately., Conclusion: Through implementation of multimodal intraoperative monitoring techniques, potential neurologic injuries are localized and managed in real time. Intraoperative monitoring is a valuable tool for improving the safety and outcome of spinal deformity surgery., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Dr Lenke reports board membership in OREF and GSO; personal consultancy fees from DePuy Synthes Spine, K2M, and Medtronic; personal expert testimony fees from Fox Rothschild, LLP; grants from AO Spine, Scoliosis Research Society, DePuy Synthes Spine, Setting Scoliosis Straight Foundation, EOS, and philanthropic research funding; royalties from Medtronic; and personal travel accommodation/meeting expenses from AOSpine, Broadwater, Seattle Science Foundation, Scoliosis Research Society, and the Spinal Research Foundation. Dr Lehman reports grants from Department of Defense Peer Reviewed Orthopaedic Research Program (PRORP); personal fees and nonfinancial support from DePuy Synthes Spine; personal fees and nonfinancial support from Stryker; and personal fees and nonfinancial support from Medtronic.

Study Design: Therapeutic anti-infective trial in rabbits., Objective: The purpose of the present study was to assess the efficacy of intrawound tobramycin powder in terms of eradicating a known bacterial contamination in an Escherichia coli-infected rabbit spinal implantation model., Summary of Background Data: Implant-associated surgical site infections (SSIs) remain a dreaded complication of spinal surgery. Currently, >30% of all spine SSIs are secondary to gram-negative bacteria., Methods: Twenty healthy New Zealand white female rabbits underwent simulated partial laminectomies and implantation of a 10-mm titanium wire at L5-L6. All surgical sites were inoculated with 100 μL of tobramycin-sensitive E coli (EC ATCC 25922, 1 × 10 colony-forming units [CFU]/mL). Before closure, tobramycin powder (120 mg) was placed into the wound of 10 rabbits. All rabbits were sacrificed on postoperative day 4. Tissue and wire samples were explanted for bacteriologic analysis. A Fisher exact test was used to assess differences in categorical variables and an independent samples t test was used to assess mean group differences., Results: The experimental and control rabbits were similar in weight (mean ± standard deviation, 3.22 ± 0.12 kg and 3.22 ± 0.14 kg, respectively, P = 1.0), sex distribution, and duration of surgery (13.1 ± 2.4 minutes and 11.6 ± 2.1 minutes, P = 0.39). Bacterial cultures of the tissue samples were negative for all 10 tobramycin-treated rabbits and positive for all 10 control rabbits (P < 0.0001). Bacterial growth occurred in 39 of 40 samples from control rabbits, but zero of the 40 samples from the tobramycin group (P < 0.0001). Blood culture samples from all rabbits were negative for bacterial growth. No rabbit had evidence of sepsis or tobramycin toxicity., Conclusion: In a rabbit spine-infection model, intrawound tobramycin eliminated E coli surgical site contamination. All rabbits without intrawound tobramycin had persistent E coli contamination., Level of Evidence: N /A.

Study Design: A randomized complete block animal spinal implant infection model with internal control., Objective: The aim of this study was to develop a spinal implant animal infection model to simulate postoperative gram-negative wound infection., Summary of Background Data: Implant-associated surgical site infections (SSIs) remain a dreaded complication of spinal surgery. Currently, over 30% of all spine SSIs are secondary to gram-negative bacteria. Traditional animal models have utilized gram-positive inoculums to simulate postoperative infection, but there exists no model in the literature for gram-negative infection in the setting of spinal instrumentation., Methods: Five New Zealand white female rabbits underwent simulated partial laminectomies and implantation of a 5 mm titanium wire adjacent to the spinous processes of vertebra T4, T9, L1, and L6 to mimic posterior spinal instrumentation. The second site, T9, was used as the sterile internal control sites, while all other sites were challenged with varying inoculums of Escherichia coli (EC American Type Culture Collection 25922): 10, 10, 10, 10, and 10 Colony Forming Units (CFU). The rabbits were sacrificed 4 days postoperatively and bacterial loads were assayed from the implants and surrounding tissue., Results: No evidence for infection was observed in any of the sterile control sites. The lowest inoculum of E. coli (10 CFU) did not produce a reliable infection. Inoculation with 10 CFU created a consistent soft tissue infection, but inconsistent infection on implants. Inoculation with 10 CFU was required to consistently produce both soft tissue and implant infection., Conclusion: Consistent soft tissue and implant infection was produced with inoculation of 10 CFU of E. coli. Gram-negative infections represent greater than 30% of all spinal SSIs, and this animal model can reliably reproduce such infections with spinal instrumentation that can guide future development of anti-infective therapies., Level of Evidence: 2.

Background: Given the increasing societal focus on health care utilization and value-based care, it is essential to understand the demographic and economic data surrounding percutaneous vertebral augmentation procedures performed in the United States. Double-blinded prospective randomized controlled trials have shown no benefit to the use of vertebroplasty over a sham procedure in the treatment of vertebral fractures. Contrastingly, kyphoplasty may be beneficial when appropriately indicated., Methods: The National Inpatient Sample (NIS) database was queried for patients who underwent either kyphoplasty (ICD-9-CM 81.66) or vertebroplasty (ICD-9-CM 81.65) procedures between 2006 and 2014 across 44 states. Demographic and economic data were obtained which included the annual number of surgeries, age, sex, insurance type, location, and frequency of routine discharge. The NIS database represents a 20% sample of discharges from U.S. hospitals, which is weighted to provide national estimates., Results: In 2014, an estimated total number of 19,420 kyphoplasty and 6,130 vertebroplasty procedures were performed across the United States. The number of vertebroplasty procedures decreased 53% from 13,128 in 2008. Similarly, the number of kyphoplasty procedures decreased 17% from 23,320 in 2007. Based on payer, Medicare patients comprised 83% of those billed for kyphoplasty and vertebroplasty, and 75% of procedures were utilized in areas designated as "not low income". In 2014, patients in the South Atlantic region comprised 24% of vertebroplasty and 28% of kyphoplasty cases, far more than any other region. Additionally, kyphoplasty and vertebroplasty were more often performed in teaching facilities rather than community hospitals (60% and 67%, respectively)., Conclusions: Since the publication of two double-blind, prospective randomized controlled trials showed no benefit of vertebroplasty over a sham procedure, there has been a significant decrease in both kyphoplasty and vertebroplasty procedures., Competing Interests: Conflicts of Interest: SC Ludwig, MD reports the following disclosures—AO Spine North America Spine Fellowship Support (Research support); ASIP, ISD (Stock or stock options); Cervical Spine Research Society (Board or committee member); DePuy, A Johnson & Johnson Company (IP royalties; Paid consultant; Paid presenter or speaker); Globus Medical (Paid consultant; Research support); Journal of Spinal Disorders and Techniques, The Spine Journal, Contemporary Spine Surgery (Editorial or governing board); K2Medical (Paid consultant, Research support); Synthes (Paid consultant; Paid presenter or speaker); Thieme, QMP (Publishing royalties, financial or material support). LG Lenke, MD reports the following disclosures—Board Membership in OREF and GSO; Personal fees from Consultancy-DePuy Synthes Spine, K2M, and Medtronic; Personal fees from Expert Testimony-Fox Rothschild, LLP; Grants from AO Spine, Scoliosis Research Society, DePuy Synthes Spine, Setting Scoliosis Straight Foundation, EOS; Royalties from Patents-Medtronic; Personal fees from Travel accommodations/meeting expenses-AOSpine, Broadwater, Seattle Science Foundation, Scoliosis Research Society, The Spinl Research Foundation; Other grants from Fellowship Grant-AOSpine, North America, and grants from Philanthropic research funding outside the submitted work. RA Lehman, MD reports the following disclosures—Grants from PRORP (Department of Defense Peer Reviewed Orthopaedic Research Program); Personal fees and non-financial support from DePuy Synthes Spine; Personal fees and non-financial support from Stryker; Personal fees and non-financial support from Medtronic. The other authors have no conflicts of interest to declare.

Study Design: Broad narrative review., Objective: To review the evolution, operative technique, outcomes, and complications associated with posterior vertebral column resection., Methods: A literature review of posterior vertebral column resection was performed. The authors' surgical technique is outlined in detail. The authors' experience and the literature regarding vertebral column resection are discussed at length., Results: Treatment of severe, rigid coronal and/or sagittal malalignment with posterior vertebral column resection results in approximately 50-70% correction depending on the type of deformity. Surgical site infection rates range from 2.9% to 9.7%. Transient and permanent neurologic injury rates range from 0% to 13.8% and 0% to 6.3%, respectively. Although there are significant variations in EBL throughout the literature, it can be minimized by utilizing tranexamic acid intraoperatively., Conclusion: The ability to correct a rigid deformity in the spine relies on osteotomies. Each osteotomy is associated with a particular magnitude of correction at a single level. Posterior vertebral column resection is the most powerful posterior osteotomy method providing a successful correction of fixed complex deformities. Despite meticulous surgical technique and precision, this robust osteotomy technique can be associated with significant morbidity even in the most experienced hands., Competing Interests: Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objectives: The purpose of this study was to evaluate current fixation techniques in the operative fixation of distal humerus fractures, both with conventional and locked plating in both parallel and orthogonal orientation., Methods: Twenty-eight upper extremities from 14 cadavers were prepared to create 4 implant testing constructs: Synthes locking plates (IMP1) (medial and posterolateral with lateral flange), Acumed parallel locking plates (IMP2), Smith & Nephew orthogonal locking plates (IMP3), and Synthes orthogonal 3.5-reconstruction plating (IMP4) (1 posterolateral and 1 medial). A 5-mm supracondylar osteotomy was made to simulate the fracture. Stiffness in axial and sagittal plane loading, fatigue properties (over 5000 cycles), and ultimate strength were determined for each construct by biomechanical testing., Results: The parallel locking plates (IMP2) exhibited the highest stiffness in axial load and the highest ultimate strength (P < 0.05). No significant differences in sagittal plane stiffness and in the fatigue properties were seen across the locking plate groups, regardless of orientation. Locked plating constructs performed significantly better in all categories when compared with conventional nonlocked plating. Plastic deformation and implant loosening were the main modes of failure after ultimate strength test., Conclusion: Parallel locking plate configuration showed significantly higher stiffness to axial load and ultimate failure strength when compared with orthogonal locked and nonlocked plating. Locked plating configurations performed significantly better than nonlocked plating configurations, regardless of orientation. Although parallel orientation seems biomechanically superior, translation to the clinical setting may prove difficult when taking surrounding soft tissue and exposure into consideration.

Originally described by Monteggia and later classified by Bado, elbow dislocations with concurrent radial and ulnar shaft fractures with distal radioulnar joint (DRUJ) disruption are considered operative cases with high-energy injurious etiologies. Here, we present an unclassifiable Monteggia variant fracture suffered through a high axial load mechanism in a 47-year-old female. The fracture pattern initially exhibited included a divergent elbow dislocation, a radial shaft fracture, plastic deformation of the distal ulna, and DRUJ instability. Here we describe the pattern in detail, along with definitive treatment and clinical outcome at 1 year follow-up.