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Study Design: Retrospective clinical data analysis. Objective: To investigate the misplacement rate and related clinical complications of percutaneous pedicle screw insertion in the thoracic and lumbar spine. Summary Of Background Data: Percutaneous insertion of cannulated pedicle screws has been developed as a minimally invasive alternative to the open technique during instrumented fusion procedures of the thoraco-lumbar spine. The reported rate of screw misplacement using open techniques is well described, however data is lacking on the exact failure rate of the percutaneous technique. Methods: A total of 424 percutaneously inserted pedicle screws from 2007 to 2010 were analyzed in 88 patients, from a single surgeon series (RJM). Axial reformatted computer tomographic images were examined by 2 independent observers and individual and consensus interpretation was obtained for each screw position. A simple grading system was used for assessment of screw accuracy--Grade 0: screw within cortex of pedicle; Grade 1: screw thread breach of wall of pedicle <2 mm; Grade 2: significant breach >2 mm with no neurological compromise; Grade 3: complication including pedicle fracture, anterior breach with neuro-vascular compromise, and lateral or medial breach with neurological sequelae. Results: The indications for percutaneous pedicle screw insertion include: degenerative (78%), trauma (13%), tumour (8%), and infection (1%). Pedicle screws were inserted into level T4 to S1. The most common levels performed include L4 and L5 with the most common indication for surgery being an L4/5 spondylolisthesis. 383 out of 424 screws (90.3%) were placed in the cortical shell of the pedicle (Grade 0). Forty-one screws (9.7%) were misplaced from T4 to S1. Of these, the majority were Grade 1 pedicle violations (24 screws; 5.7%), with 15 Grade 2 violations (3.5%) and 2 Grade 3 violations (0.5%). Of the 2 Grade 3 pedicle violations, both were pedicle fractures but only 1 had associated neurological deficit (L4 radiculopathy postoperatively). Conclusion: Percutaneous insertion of cannulated pedicle screws in the thoracic and lumbar spine is an acceptable technique with a low complication rate in experienced hands. The overall rate of perforation is below the higher rates reported in the literature for the open technique. Complication rates including pedicle fracture were low. [ABSTRACT FROM AUTHOR]

Background: Gait analysis is a vital tool for evaluating overall health and predicting outcomes such as mortality and cognitive decline. This study explores how normal and obese BMI categories impact gait dynamics, addressing gaps in understanding the effect of body composition on specific gait parameters., Research Question: The primary objective is to investigate differences in spatiotemporal gait parameters-specifically, gait speed, step length, cadence, and double support time-between normal and obese BMI groups to understand the effects of obesity on gait., Methods: This observational case-control study analyzed spatiotemporal gait metrics from 163 participants, using inertial measurement units (IMUs) to collect data on various gait parameters. Statistical analyses explored the relationship between BMI categories and these metrics., Results: No significant differences were found in gait speed, cadence, stride duration, or double support time between the normal and obese groups. However, significant differences were identified in age, hypertension prevalence, balance problems, and the incidence of falls, emphasizing the complex effects of obesity on factors influencing gait stability., Significance: This study contributes to our understanding of obesity's impact on gait by highlighting the need to consider associated health and stability parameters. These findings prompt a re-evaluation of how BMI is integrated into clinical gait assessments and emphasize the necessity for personalized healthcare strategies. This research highlights the importance of future studies with larger, more diverse populations and a wider array of biomechanical measures to dissect the relationship between BMI, body composition, and gait dynamics.

Background: Anterior lumbar interbody fusion (ALIF) uses a broad-footprint interbody cage designed to maximize fusion rates for treating degenerative disc disease. Bone graft substitutes are being increasingly utilized during ALIF to replace or supplement autologous iliac crest bone grafts. This approach aims to optimize fusion efficacy while minimizing associated postoperative complications. The objective of this systematic review was to examine recent studies on fusion rates and postoperative complications associated with bone graft substitutes used in ALIF., Methods: We conducted a systematic review of the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase, MEDLINE, and PubMed databases, to critically examine a decade of research (January 1, 2012, to July 6, 2023) on the effectiveness and safety of various bone graft substitutes in ALIF. This timeframe was chosen to build on a previous systematic review published in 2013. The PRISMA guidelines were used., Results: In total, 27 articles met our stringent inclusion and exclusion criteria. A substantial portion of these studies (67%) focused on recombinant human bone morphogenetic protein-2 (rhBMP-2) and highlighted its efficacy for achieving high fusion rates. However, the literature presents a dichotomy regarding the association of rhBMP-2 with increased postoperative complications. Notably, the methodologies for evaluating spinal fusion varied across studies. Only one-third of studies employed computed tomography to assess interbody fusion at 12 months postoperatively, highlighting the urgent need to establish uniform fusion criteria to facilitate more accurate comparative analyses. Moreover, there was considerable variability in the criteria used for diagnosing and detecting postoperative complications, significantly influencing the reported incidence rates., Conclusions: This review underscores the need for continued research into bone graft substitutes, particularly focusing on assessment of long-term complications. Future research endeavors should concentrate on developing comprehensive clinical guidelines to aid in the selection of the most suitable bone graft substitutes for use in ALIF, thereby enhancing patient outcomes and surgical efficacy., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jss.amegroups.com/article/view/10.21037/jss-24-24/coif). R.J.M. serves as the current Editor-in-Chief and G.M.M. serves as an unpaid editorial board member of Journal of Spine Surgery. R.J.M. is a consultant for Australian Biotechnologies, A-Spine, LifeHealthcare, and Medacta. G.M.M. is a consultant for Australian Biotechnologies, Globus, and LifeHealthcare. The other authors have no conflicts of interest to declare., (2024 AME Publishing Company. All rights reserved.)

The field of spinal robotics has witnessed considerable advances, which have primarily focused on enhancing pedicle screw placement. This article critically evaluates the current direction of spinal robotics development, raising concerns about the disproportionate emphasis on pedicle screw placement when existing techniques already yield commendable results. Discussions on various parameters, including quality, cost-effectiveness, and accessibility, highlight the need for a broader perspective in the development of robotics for spinal surgery. Comparative analyses reveal that navigation systems offer cost-effective and time-efficient alternatives to robotics, with similar accuracy levels. Patient demand for robotic interventions is influenced by perceived superiority, warranting careful consideration of public sentiment. This article also underscores the need for future spine surgeons to maintain proficiency in traditional techniques. The influence of industry and key opinion leaders in steering the focus toward pedicle screw placement is discussed, emphasizing the need for a more holistic approach. Accessibility issues and legal considerations in the evolving field of spinal robotics are addressed, and the potential for robotics to enhance various aspects of surgical procedures beyond pedicle screw placement is explored. In conclusion, we advocate for a shift in focus in spinal robotics, emphasizing the untapped potential to streamline common surgical procedures (such as discectomy, laminectomy, and endoscopy), enhance precision, and improve patient outcomes in areas beyond pedicle screw placement. Future advances in spinal robotics have the potential to transform the surgical landscape, benefitting all stakeholders, including patients, surgeons, and hospitals., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jss.amegroups.com/article/view/10.21037/jss-24-4/coif). R.J.M. serves as the Editor-in-Chief of Journal of Spine Surgery. G.M.M. and L.H.S. serves as the unpaid editorial board members of Journal of Spine Surgery. G.M.M. is a consultant for Australian Biotechnologies, Globus, and LifeHealthcare. T.A.W.Q. is an employee of LifeHealthcare. A.M.N. is a consultant for Mainstay and Evolution Surgical. R.J.M. is a consultant for Australian Biotechnologies, A-Spine, LifeHealthcare, and Medacta. L.H.S. is a consultant for Katomed and Kyocera. The authors have no other conflicts of interest to declare., (2024 AME Publishing Company. All rights reserved.)

Endoscopic spine surgery has evolved exponentially. However, the two-dimensional (2D) view results in lack of stereoscopic vision and depth perception, contributing to the steep learning curve. This case report recounts a world first trial of a three-dimensional (3D) endoscopic system that converts 2D to 3D images and explores its potential role in the surgical management of degenerative lumbar spine diseases. The 3D endoscopic system was used for two patient cases and both 2D and 3D images were displayed side by side and compared. Advantages of the 3D endoscopic system include increased perception of depth, rapid identification of bleeding points, and greater visualization of anatomical details. Field of view and exposure were identical in 2D and 3D views. Limitations include costs and need for additional equipment. Overall, 3D endoscopy improved depth perception, instrument manoeuvrability, and recognition of anatomical details. This case report can guide further research and training in endoscopic spine surgery., Competing Interests: The authors have no conflicts of interest., (Published by Oxford University Press and JSCR Publishing Ltd. © The Author(s) 2024.)

Background: Three-dimensional printing (3DP) is increasingly used to individualise surgery and may be an effective tool for representing patient anatomy. Current literature on patient-specific anatomical models (biomodels) for minimally invasive spinal surgery is a limited number of case series and cohort studies. However, studies investigating 3DP in other specialties have reported multiple benefits., Methods: This prospective study considered a series of patients (n=33) undergoing elective endoscopic spinal surgery, including combinations of microdiscectomy (n=27), foraminotomy (n=7), and laminectomy (n=3). These surgeries were conducted at vertebral levels ranging from L2/3 to L5/S1. The surgeon then recorded the impact on preoperational planning, intraoperative decision-making and accelerating the learning curve with a qualitative questionnaire., Results: There were benefits to planning in 54.5% of cases (n=18), improved intraoperative decision-making in 60.6% of cases (n=20). These benefits were reported more frequently earlier in the cases, with improvements to learning reported in 60% of the first five cases and not in subsequent cases. The surgeon commented that the biomodels were more useful on., Conclusions: The rates of preoperative and intraoperative benefits are consistent with existing studies, and the early benefit to the learning curve may be suitable for applications to surgical training. Additional research is required to determine the practicality of biomodels and their impact on patient outcomes for endoscopic spinal surgery., Competing Interests: Conflicts of Interest: Both authors have completed the ICMJE uniform disclosure form (available at https://jss.amegroups.com/article/view/10.21037/jss-23-103/coif). R.J.M. serves as the Editor-in-Chief of Journal of Spine Surgery. The authors have no other conflicts of interest to declare., (2024 Journal of Spine Surgery. All rights reserved.)

Background: Established health-related quality of life scores do not consider both subjective and objective indices of health. We propose the subjective and objective quality of life score (SOQOL) for the comprehensive assessment of health-related quality of life and aim to provide normative population data. The SOQOL is compatible with smartphone applications, allowing widespread use on a global scale., Methods: Normative SOQOL population data was sourced from pre-existing datasets on the EQ-5D-5L, daily step count, and walking speed. Normative values were calculated using weighted grand means. We trialled the SOQOL in a group of five patients presenting to a spinal neurosurgery clinic., Results: SOQOL scores decreased with age, and women had lower scores in every age group. In our case series, the spine patients with the biggest SOQOL deficit compared to age- and sex-matched population averages were found to be surgical while the rest were non-surgical., Conclusions: The SOQOL shows promise as a simple and effective scoring tool that is compatible with smartphones, potentially useful for screening in primary and specialized care settings, and for assessment following healthcare interventions. This study, however, is preliminary, and the findings are primarily suggestive. They underline the necessity for future, more comprehensive studies to validate and expand upon these initial observations. The conclusion of both this abstract and the full paper will clearly state these limitations and the preliminary nature of the study., (© 2024. The Author(s).)

Although placebo-controlled trials are considered the gold standard for evaluating the efficacy of healthcare interventions, they can be perceived to be controversial and challenging to conduct for surgical treatments. The SUcceSS trial is the first placebo-controlled trial of lumbar decompression surgery for symptomatic lumbar canal stenosis. The SUcceSS trial has experienced common issues affecting the implementation of randomised placebo-controlled surgery trials, accentuated by the COVID-19 pandemic. Using the SUcceSS trial as an example, we discuss key challenges and mitigation strategies specific to the conduct of a randomised placebo-controlled surgical trial. Overall, the key lessons learned were (i) involving key stakeholders early and throughout the trial design phase may increase clinician and patient willingness to participate in a placebo-controlled trial of surgical interventions, (ii) additional resources (e.g. budget, staff time) are likely required to successfully operationalise trials of this nature, (iii) the level of placebo fidelity, timing of randomisation relative to intervention delivery, and nuances of the surgical procedure under investigation should be considered carefully. Findings are based on one example of a placebo-controlled surgical trial; however, researchers may benefit from employing or building from the strategies described and lessons learned when designing or implementing future trials of this nature., (© 2023. The Author(s).)

Background: Surgical procedures involving the hip, knee, or spine represent a majority of orthopaedic procedures performed electively in the health care system. Postoperative care is a key aspect of surgery and mobilisation without injury is the primary objective. Recent advances in wearable technologies allow objective evaluation of walking metrics to inform and guide postoperative care following orthopaedic surgery., Purpose: The aim of this scoping review is to explore current applications of wearable devices, objective data capture and gait analysis in monitoring postoperative recovery following commonly performed elective orthopaedic procedures of the hip, knee and spine., Methods: A search against pre-defined criteria was performed on the following scientific databases from date of inception to February 28th, 2021: Medline (via OvidSP), Embase (via OvidSP) and Cochrane Library (via CENTRAL). Data were collected according to a predetermined checklist including study participants, surgery, wearable device (model), sensor location, and monitoring parameters such as mobility metrics, monitoring timepoints and monitoring duration for each study included in our review. Quality was assessed independently using the Newcastle Ottawa Scale (NOS)., Conclusions: To our knowledge, this is the first review of wearable monitoring (of postoperative recovery) following hip, knee and spine surgery. Patients undergoing elective orthopaedic procedures may benefit from wearable monitoring of their walking health and mobility metrics., (© 2023. The Author(s).)

Competing Interests: Declarations of Competing Interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Competing Interests: Conflicts of Interest: The authors are consultants for Medacta International.

Background and Objective: Recombinant human bone morphogenetic protein-2 (rhBMP-2) has been extensively studied in preclinical, animal, and human studies and has been used widely in spine fusion surgery. Evidence demonstrates that fusion rates with rhBMP-2 are similar to or higher than those achieved with autologous bone graft. However, there have been concerns regarding the cost, optimal dosage, and potential complications of rhBMP-2 use in spine surgery. The objective of this paper is to provide a current review of the available evidence regarding rhBMP-2 and other bone graft substitutes used for spinal surgery., Methods: We searched Ovid Medline, PubMed, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, American College of Physicians Journal Club, and Database of Abstracts of Review of Effectiveness for 2 studies regarding physiology of bone fusion in spine surgery, formulations and indications of rhBMP-2, cancer risk of rhBMP-2, and alternatives to rhBMP-2 published from 1965 to 2022 in English., Key Content and Findings: The debate regarding indications and cost effectiveness of rhBMP-2 is presented based on increasing data and use criteria. Here, we focus on the effectiveness and economic costs (both direct and indirect) of rhBMP-2 and alternative bone graft substitutes. Based on the cumulative literature, we provide recommendations for rhBMP-2 use in spine surgery., Conclusions: Based on our review of the literature, we recommend the following: (I) clear informed consent processes between surgeons and patients regarding current evidence of the benefits and risks of using rhBMP-2 and available alternative bone graft substitutes. (II) Consideration of rhBMP-2 for spinal fusion surgery (excluding anterior cervical procedures), especially adult spinal deformity (ASD) surgery, lumbar surgery for multilevel degenerative disease, revision surgery for pseudoarthrosis, and surgery in patients with a low-quantity or low-quality autograft. (III) Regulatory oversight of the type, volume, and dose of bone graft substitute (both per level and per procedure) to ensure appropriate indications, prevent excessive usage, and thereby enhance cost containment., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jss.amegroups.com/article/view/10.21037/jss-22-23/coif). The authors have no conflicts of interest to declare., (2022 Journal of Spine Surgery. All rights reserved.)

Objective: Using a chest-based inertial wearable sensor, we examined the quantitative gait patterns associated with lumbar disc herniation (LDH), lumbar spinal stenosis (LSS), and chronic mechanical low back pain (CMLBP). 'Pathological gait signatures' were reported as statistically significant group difference (%) from the 'normative' gait values of an age-matched control population., Methods: A sample of patients presenting to the Prince of Wales Private Hospital (Sydney, Australia) with primary diagnoses of LDH, LSS, or CMLBP were recruited. Spatial, temporal, asymmetry, and variability metrics were compared with age-matched (±2 years) control participants recruited from the community. Participants were fitted at the sternal angle with an inertial measurement unit, MetaMotionC, and walked unobserved (at a self-selected pace) for 120 m along an obstacle-free, carpeted hospital corridor., Results: LDH, CMLBP, and LSS groups had unique pathological signatures of gait impairment. The LDH group (n = 33) had marked asymmetry in terms of step length, step time, stance, and single-support asymmetry. The LDH group also involved gait variability with increased step length variation. However, distinguishing the CMLBP group (n = 33) was gait variability in terms increased single-support time variation. The gait of participants with LSS (n = 22) was both asymmetric and variable in step length., Conclusions: Wearable sensor-based accelerometry was found to be capable of detecting the gait abnormalities present in patients with LDH, LSS, and CMLBP, when compared to age-matched controls. Objective and quantitative patterns of gait deterioration uniquely varied between these subtypes of lumbar spine disease. With further testing and validation, gait signatures may aid clinical identification of gait-altering pathologies., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: The spine surgeon's understanding of an individual patient's burden of disease and functional disability in daily life is shaped by patient-reported outcome measures (PROMs). Although PROMs are useful in understanding the patient's perception of their disease, the use of PROMs constitutes a "snapshot" approach of single timepoint data capture, omitting day-to-day fluctuations in functional status. We introduce the concept of kinetics when considering continuous and objective postoperative patient monitoring with wearable sensors., Methods: A prospective single-centre series was performed using patients either undergoing lumbar decompression for lumbar spinal stenosis (LSS) (n=12), or posterior lumbar fusion for degenerative spondylolisthesis (n=12). The Oswestry Disability Index (PROM) was conducted preoperatively and 12-weeks postoperatively. During this timeframe, continuous measurements of step count and distance travelled were made using a wrist-based wearable accelerometer., Results: Over the 12-week study period, mean daily step count for all participants improved from 4,700 to 7,700 steps per day (P=0.013), following an initial dip in total steps taken. The mean daily distance travelled improved from 3,300 to 5,300 meters per day (P=0.003). Decompression group recovered at a faster rate than the fusion group., Conclusions: Although overall improvement was similar between the decompression and fusion groups, the recovery kinetics varied. The recovery kinetics approach of continuous postoperative monitoring provides additional insight to postoperative patient progress., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jss.amegroups.com/article/view/10.21037/jss-22-5/coif). RJM serves as an Editor-in-Chief of Journal of Spine Surgery, and reports funding of wearable equipment from Jasper Medical Innovations. KR reports administrative support from NeuroSpine Clinic. The other authors have no conflicts of interest to declare., (2022 Journal of Spine Surgery. All rights reserved.)

•The proposed GSi algorithm aims to objectively evaluate the walking impairment associated with lumbar disc herniation (LDH).•GSi is calculated as deviation from mean (age-matched) normative values for gait velocity, step time asymmetry and step length asymmetry.•Clinical performance was assessed in a prospective, single surgeon series of 33 lumbar disc herniation (LDH) patients.•GSi was lower in LDH participants with significant distribution between surgical and conservative management subgroups., Competing Interests: The authors declare that they have no competing interests., (© 2022 The Authors.)

Background: Musculoskeletal disorders can contribute to injurious falls and incur significant societal and healthcare burdens. Identification of fallers from non-fallers through wearable-based gait analysis can facilitate timely intervention to assist mobility and prevent falls whilst improving care and attention for high fall-risk patients. In this study, we use wearable sensor-based gait analysis to introduce a novel variable to assess walking stability in fallers and non-fallers - the Walking Orientation Randomness Metric. The WORM score quantifies the stability, or 'figure-of-eight' motion of a subject's trunk during walking as an indicator of a falls-predictive (pathological) gait., Methods: WORM is calculated as the 'figure-of-eight' oscillation mapped out in the transverse-plane by the upper body's centre-point during a walking bout. A sample of patients presenting to the Prince of Wales Hospital (Sydney, Australia) with a primary diagnosis of "falls for investigation" and age-matched healthy controls (non-fallers) from the community were recruited. Participants were fitted at the sternal angle with the wearable accelerometer, MetaMotionC (Mbientlab Inc., USA) and walked unobserved (at self-selected pace) for 5-50 m along an obstacle-free, carpeted hospital corridor., Results: Participants comprised of 16 fallers (mean age: 70 + 17) and 16 non-fallers (mean age: 70 + 9) based on a recent fall(s) history. The (median) WORM score was 17-fold higher (p < 0.001) in fallers (3.64 cm) compared to non-fallers (0.21 cm). ROC curve analyses demonstrate WORM can discriminate fallers from non-fallers (AUC = 0.97). Diagnostic analyses (cut-off > 0.51 cm) show high sensitivity (88%) and specificity (94%)., Conclusion: In this pilot study we have introduced the WORM score, demonstrating its discriminative performance in a preliminary sample size of 16 fallers. WORM is a novel gait metric assessing walking stability as measured by truncal way during ambulation and shows promise for objective and clinical evaluation of fallers., (© 2022. The Author(s).)

Objectives: To collate the current state of knowledge and explore differences in the spatiotemporal gait patterns of degenerative lumbar spine diseases: lumbar spinal stenosis (LSS), lumbar disc herniation (LDH) and low back pain (LBP)., Background: LBP is common presenting complaint with degenerative lumbar spine disease being a common cause. In particular, the gait patterns of LSS, LDH and mechanical-type (facetogenic and discogenic) LBP is not established., Methods: A search of the literature was conducted to determine the changes in spatial and temporal gait metrics involved with each type of degenerative lumbar spine disease. A search of databases including Medline, Embase and PubMed from their date of inception to April 18th, 2021 was performed to screen, review and identify relevant studies for qualitative synthesis. Seventeen relevant studies were identified for inclusion in the present review. Of these, 5 studies investigated gait patterns in LSS, 10 studies investigated LBP and 2 studies investigated LDH. Of these, 4 studies employed wearable accelerometry in LSS (2 studies) and LBP (2 studies)., Conclusions: Previous studies suggest degenerative diseases of the lumbar spine have unique patterns of gait deterioration. LSS is characterised by asymmetry and variability. Spatiotemporal gait deterioration in gait velocity, cadence with increased double-support duration and gait variability are distinguishing features in LDH. LBP involves marginal abnormalities in temporal and spatial gait metrics. Previous studies suggest degenerative diseases of the lumbar spine have unique patterns of gait deterioration. Gait asymmetry and variability, may be relevant metrics for distinguishing between the gait profiles of lumbar spine diseases., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jss.amegroups.com/article/view/10.21037/jss-21-91/coif). The series “Objective Monitoring and Wearable Technologies including Sensor-Based Accelerometers and Mobile Health Applications for the Spine Patient” was commissioned by the editorial office without any funding or sponsorship. RJM served as the unpaid Guest Editor of the series and serves as the Editor-in-Chief of Journal of Spine Surgery. RDF and PN served as the unpaid Guest Editors of the series and serve as unpaid Assistant Managing Editors of Journal of Spine Surgery. The authors have no other conflicts of interest to declare., (2022 Journal of Spine Surgery. All rights reserved.)

Background: Cervical spine range of motion (ROM) assessment has long been carried out via use of the universal goniometer (UG) as an objective tool in the evaluation of patient rehabilitation pre- and post-operatively. The advent of novel ROM assessment technology, such as HALO digital goniometer (DG), presents an avenue for research and potential application within clinical and surgical settings. The objective of this study was to examine the reliability and validity of the HALO DG in the assessment of the active ROM of the cervical spine., Methods: One hundred healthy subjects were recruited for the study and were split into two groups to be assessed by either physiotherapists or medical students. The methodology for cervical spine ROM assessment was carried out per the American Association of Orthopaedic Surgeons (AAOS) guidelines. The reliability analysis was completed using IBM SPSS Statistics 25, calculating the intraclass correlation coefficients (ICC) to determine both the intra- and inter-rater reliability of the device., Results: Inter-rater reliability within the physiotherapist cohort with the DG (ICCr =0.477, 0.718, 0.551) was higher compared to the UG (ICCr =0.380, 0.510, 0.255) for active cervical flexion, lateral flexion, and rotation, respectively. The UG (ICCr =0.819) showed better reliability versus the DG (ICCr =0.780) when assessing cervical extension. Similarly, in the medical student cohort, the DG outperformed the UG in all movement except cervical lateral flexion. When assessing for intra-rater reliability, the DG (ICCm =0.507, 0.773, 0.728, 0.691) performed better than the UG (ICCm =0.487, 0.529, 0.532, 0.585) in cervical flexion, extension, lateral flexion, and rotation, respectively., Conclusions: The present validation study identified the DG as a reliable substitute for the UG., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jss.amegroups.com/article/view/10.21037/jss-21-92/coif). The series “Objective Monitoring and Wearable Technologies including Sensor-Based Accelerometers and Mobile Health Applications for the Spine Patient” was commissioned by the editorial office without any funding or sponsorship. RJM served as the unpaid Guest Editor of the series and serves as the Editor-in-Chief of Journal of Spine Surgery. MHP and PR serve as the unpaid Associate Editors of Journal of Spine Surgery. The authors have no other conflicts of interest to declare., (2022 Journal of Spine Surgery. All rights reserved.)

Background: The purpose of this scoping review was to explore the current applications of objective gait analysis using inertial measurement units, custom algorithms and artificial intelligence algorithms in detecting neurological and musculoskeletal gait altering pathologies from healthy gait patterns., Methods: Literature searches were conducted of four electronic databases (Medline, PubMed, Embase and Web of Science) to identify studies that assessed the accuracy of these custom gait analysis models with inputs derived from wearable devices. Data was collected according to the preferred reporting items for systematic reviews and meta-analysis statement guidelines., Results: A total of 23 eligible studies were identified for inclusion in the present review, including 10 custom algorithms articles and 13 artificial intelligence algorithms articles. Nine studies evaluated patients with Parkinson's disease of varying severity and subtypes. Support vector machine was the commonest adopted artificial intelligence algorithm model, followed by random forest and neural networks. Overall classification accuracy was promising for articles that use artificial intelligence algorithms, with nine articles achieving more than 90% accuracy., Conclusions: Current applications of artificial intelligence algorithms are reasonably effective discrimination between pathological and non-pathological gait. Of these, machine learning algorithms demonstrate the additional capacity to handle complicated data input, when compared to other custom algorithms. Notably, there has been increasing application of machine learning algorithms for conducting gait analysis. More studies are needed with unsupervised methods and in non-clinical settings to better reflect the community and home-based usage., Competing Interests: Declaration of conflicting interests: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2022.)

Background: Wearable sensors, particularly accelerometers alone or combined with gyroscopes and magnetometers in an inertial measurement unit (IMU), are a logical alternative for gait analysis. While issues with intrusive and complex sensor placement limit practicality of multi-point IMU systems, single-point IMUs could potentially maximize patient compliance and allow inconspicuous monitoring in daily-living. Therefore, this review aimed to examine the validity of single-point IMUs for gait metrics analysis and identify studies employing them for clinical applications., Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses Guidelines (PRISMA) were followed utilizing the following databases: PubMed; MEDLINE; EMBASE and Cochrane. Four databases were systematically searched to obtain relevant journal articles focusing on the measurement of gait metrics using single-point IMU sensors., Results: A total of 90 articles were selected for inclusion. Critical analysis of studies was conducted, and data collected included: sensor type(s); sensor placement; study aim(s); study conclusion(s); gait metrics and methods; and clinical application. Validation research primarily focuses on lower trunk sensors in healthy cohorts. Clinical applications focus on diagnosis and severity assessment, rehabilitation and intervention efficacy and delineating pathological subjects from healthy controls., Discussion: This review has demonstrated the validity of single-point IMUs for gait metrics analysis and their ability to assist in clinical scenarios. Further validation for continuous monitoring in daily living scenarios and performance in pathological cohorts is required before commercial and clinical uptake can be expected., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://dx.doi.org/10.21037/mhealth-21-17). The authors have no conflicts of interest to declare., (2022 mHealth. All rights reserved.)

Context: Anterior lumbar interbody fusion (ALIF) is a common procedure for patients suffering degenerative, deformity, or posttraumatic pathologies of the lumbar spine., Aims: The aim of this study is to evaluate the clinical and radiological outcomes of a combination Titanium/Polyetheretherketone (Ti/PEEK) 3-screw fixation ALIF cage., Settings and Design: This was a prospective multisurgeon series of 87 patients (105 implants), with a minimum 24-month follow-up. Twelve patients (12/87) were supplemented with posterior percutaneous pedicle screw fixation for additional stability for pars defect spondylolisthesis correction. Radiological follow-up with fine-cut computed tomography (CT) scan occurred at 4-6 months, and again at 18-24 months if no fusion observed on initial CT, was performed to evaluate early and final fusion rates, and integration of the Ti/PEEK cage at the end-plate junction. Clinical follow-up included the subjective measures of pain and functional status and objective wearable device monitoring., Results: The fusion rate was 85% (97/105 implants) 6 months postoperatively, with no implant-related complications, and 95% at 24 months, based on independent radiological assessment. Patients experienced statistically significant improvement in subjective pain and functional outcomes compared to preoperative status. The objective measures revealed a daily step count with a 27% improvement, and gait velocity with a mean increase from 0.97 m/s to 1.18 m/s, at 3 months postoperatively., Conclusions: A Ti/PEEK cage, with allograft and bone morphogenetic protein-2 (BMP-2), achieved rapid interbody progression to fusion and is an effective implant for use in anterior lumbar surgery with high early fusion rates and no peri-endplate lucency. Supercritical CO 2 allograft provided an osteoconductive scaffold and combined well with BMP-2 to facilitate fusion., Competing Interests: Prof Ralph J. Mobbs is a research and design consultant for A-Spine ASIA. Prof William R. Walsh is a research and design consultant for SeaSpine, USA. Dr William C.H. Parr is founder and director of 3DMorphic Pty Ltd, Sydney, Australia. None of the other authors have any relevant conflicts of interest to declare., (Copyright: © 2022 Journal of Craniovertebral Junction and Spine.)

Hypothesis: The air-solution interface of supersaturated calcium hydrogen carbonate (Ca(HCO 3 ) 2 ) represents the highest saturation state due to evaporation/CO 2 -degassing, where calcite crystals are expected to nucleate and grow along the interface. Hence, it should be possible to form a free-standing mineral-only calcium carbonate (CaCO 3 ) microfilm at the air-solution interface of Ca(HCO 3 ) 2 . The air-solution interface of phosphate buffered saline (PBS) could represent a phase boundary to introduce a hybrid microstructure of CaCO 3 and carbonate-rich dicalcium hydroxide phosphate (carbonate-rich hydroxylapatite)., Experiments: Supersaturated Ca(HCO 3 ) 2 was prepared at high pressure and heated to form CaCO 3 microfilms, which were converted to bone-like microfilms at the air-solution interface of PBS by dissolution-recrystallisation. The microfilms were characterised by scanning electron microscopy, 3D confocal microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, laser Raman microspectroscopy, and X-ray photoelectron spectroscopy. An in situ X-ray diffraction (XRD) system that simulates the aforementioned interfacial techniques was developed to elucidate the microfilms formation mechanisms., Findings: The CaCO 3 and bone-like microfilms were free-standing, contiguous, and crystalline. The bone-like microfilms exhibited a hybrid structure consisting of a surface layer of remnant calcite and a carbonate-rich hydroxylapatite core of plates. The present work shows that the air-solution interface can be used to introduce hybrid microstructures to mineral microfilms., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)