Spine patient care with wearable medical technology: state-of-the-art, opportunities, and challenges: a systematic review.

BACKGROUND CONTEXT: Healthcare reforms that demand quantitative outcomes and technical innovations have emphasized the use of Disability and Functional Outcome Measurements (DFOMs) to spinal conditions and interventions. Virtual healthcare has become increasingly important following the COVID-19 pandemic and wearable medical devices have proven to be a useful adjunct. Thus, given the advancement of wearable technology, broad adoption of commercial devices (ie, smartwatches, phone applications, and wearable monitors) by the general public, and the growing demand from consumers to take control of their health, the medical industry is now primed to formally incorporate evidence-based wearable device-mediated telehealth into standards of care. PURPOSE: To (1) identify all wearable devices in the peer-reviewed literature that were used to assess DFOMs in Spine, (2) analyze clinical studies implementing such devices in spine care, and (3) provide clinical commentary on how such devices might be integrated into standards of care. STUDY DESIGN/SETTING: A systematic review. METHODS: A comprehensive systematic review was conducted in adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Guidelines (PRISMA) across the following databases: PubMed; MEDLINE; EMBASE (Elsevier); and Scopus. Articles related to wearables systems in spine healthcare were selected. Extracted data was collected as per a predetermined checklist including wearable device type, study design, and clinical indices studied. RESULTS: Of the 2,646 publications that were initially screened, 55 were extensively analyzed and selected for retrieval. Ultimately 39 publications were identified as being suitable for inclusion based on the relevance of their content to the core objectives of this systematic review. The most relevant studies were included, with a focus on wearables technologies that can be used in patients' home environments. CONCLUSIONS: Wearable technologies mentioned in this paper have the potential to revolutionize spine healthcare through their ability to collect data continuously and in any environment. In this paper, the vast majority of wearable spine devices rely exclusively on accelerometers. Thus, these metrics provide information about general health rather than specific impairments caused by spinal conditions. As wearable technology becomes more prevalent in orthopedics, healthcare costs may be reduced and patient outcomes will improve. A combination of DFOMs gathered using a wearable device in conjunction with patient-reported outcomes and radiographic measurements will provide a comprehensive evaluation of a spine patient's health and assist the physician with patient-specific treatment decision-making. Establishing these ubiquitous diagnostic capabilities will allow improvement in patient monitoring and help us learn about postoperative recovery and the impact of our interventions.

Assessing the cone of economy in patients with spinal disease using only a force plate: an observational retrospective cohort study.

STUDY DESIGN: This is a retrospective cohort with multiple regression modeling. OBJECTIVE: The aim is to develop a new method for estimating cone of economy (CoE) using a force plate rather than traditional motion capture. BACKGROUND: Currently, most spinal deformity surgeons rely on static radiographic parameters for alignment, balance, and outcomes data alongside patient-reported outcome measures. The CoE, the stable region of upright posture, can be objectively measured to determine the efficiency and balance of the spine. Motion capture technology is currently used to collect data to calculate CoE, but this requires expensive and complex equipment, which is a barrier to widespread adoption and clinical use of CoE measurements. Force plates, which measure pressure, are less expensive and can be used in a clinical setting. METHODS: Motion capture and a force plate were used to quantify the CoE of 473 subjects (423 spinal surgical candidates; 50 healthy controls; 271 females; age: 58.60 ± 15.27; height: 1.69 ± 0.13; weight: 81.07 ± 20.91), and a linear multiple regression model was used to predict CoE using force plate data in a human motion laboratory setting. Patients were required to stand erect with feet together and eyes open in their self-perceived balanced and natural position for a full minute while measures of sway and center of pressure (CoP) were recorded. RESULTS: The CoP variable regression model successfully predicted CoE measurements. The variables that were used to predict vertical CoE were CoP coronal sway, CoP sagittal sway, and CoP total sway in several combinations. The coefficient of determination for the head total sway model indicated a 87.0% correlation (F(3,469) = 1044.14, p < 0.001). The coefficient of determination for the head sagittal sway model indicated a 69.2% correlation (F(3,469) = 351.70, p < 0.001). The coefficient of determination for the head coronal sway model indicated a 85.2% correlation (F(3,469) = 899.27, p < 0001). CONCLUSION: Cone of economy was estimated from force plate data using center of pressure with high correlation without the use of motion capture in healthy controls and a variety of spine patients. This could lower the entry burden for measurement of the CoE in patients, enabling widespread use. This would provide surgeons objective global balance data, along with Haddas' CoE classification system, that could assist with surgical decision-making and facilitate objective monitoring surgical outcomes.

Reporting and tracking objective functional outcome measures: implementation of a summary report for gait and balance measures.

The aim of this manuscript is to describe knowledge gaps in the literature, future directions, and emerging applications of gait and balance analysis in spine surgery with regard to functional outcomes measurement. Functional outcome measurement has been established as a useful clinical and research investigational tool in musculoskeletal disease. Evidence currently supports its use in the diagnosis, treatment, and outcome measurement of multiple musculoskeletal disease states, including spinal disease, and its usefulness continues to grow as literature develops. Gait and balance analysis has proven to be broadly applicable, but most clinicians remain unfamiliar and untrained in its usage. The logistical and communication barriers are also described with the potential solutions that are on the near horizon of research. This article describes our methodology for improving conveyance of functional outcome measures in spine surgery. Additionally, we provide a case example of an adult patient with spinal deformity who is examined pre and post operatively using our methodology.

Kinematic Analysis of Combined Suture-Button and Suture Anchor Augment Constructs for Ankle Syndesmosis Injuries.

BACKGROUND: Syndesmosis injuries are common, with up to 25% of all ankle injuries being reported to involve an associated syndesmosis injury. These injuries are typically treated with cortical screw fixation or suture-button implants when indicated, but the addition of a suture anchor augment implant has yet to be evaluated. The purpose of this study was to evaluate the ability of a suture anchor augment to add sagittal plane translational and transverse plane rotational constraint to suture-button constructs with syndesmosis injuries. We hypothesized that the suture anchor augment oriented in parallel with the fibers of an injured anterior-inferior tibiofibular ligament (AITFL) in addition to a suture-button construct would achieve physiological motion and stability at the syndesmosis through increased rotational and translational constraint of the fibula. METHODS: Eleven fresh-frozen cadaver ankles were stressed in external rotation using a custom-made ankle rig. Each ankle had simultaneous recording of ultrasound video, 6 degrees-of-freedom kinematics of the fibula and tibia, and torque as the ankle was stressed by an examiner. The ankles were tested in 6 different states: native uninjured; injured with interosseous ligament and AITFL sectioned; 1× suture button; 2× suture buttons, divergent; 1× suture anchor augment with 2× suture buttons, divergent; and 1× suture anchor augment with 1× suture buttons. RESULTS: Only the suture anchor augment + 2× suture buttons and suture anchor augment + 1× suture-button constructs were found to be significantly different from the injured state (P = .0003, P = .002) with mean external rotation of the fibula. CONCLUSION: Overall, the most important finding of this study was that the addition of a suture anchor augment to suture-button constructs provided a mechanism to increase external rotational constraint of the fibula. CLINICAL RELEVANCE: This study provides a mechanistic understanding of how the combined suture-button and suture anchor augment construct provides an anatomically similar reconstruction of constraints found in the native ankle. However, none of the constructs examined in this study were able to fully restore physiologic motion.

Muscular architecture of the popliteus muscle and the basic science implications.

BACKGROUND: The function of the popliteus muscle is largely treated as a static stabilizer and has a lack of basic muscular architectural data to enable study of its dynamic function. A large volume of literature supports its static function and the essential need for reconstruction in the posterolateral knee when injured to restore knee stability. HYPOTHESIS/PURPOSE: We hypothesize that the popliteus muscle is more significant as a dynamic presence in the knee. METHODS: A collection of popliteus architectural data was collected from 28 cadaver specimens (mean (SD) 76 years (11)). Physiological cross-sectional area of the popliteus and semimembranosus muscles were calculated from muscle volume and fiber length to power future muscle force prediction models. Posterior knee muscle trajectories were measured with respect to the longitudinal axis of the tibia. A 2-tailed T test was performed. RESULTS: Significant differences between males and females were found for both the popliteus (p = 1.1E-05) and semimembranosus (p = 2.0E-05) muscle volumes. Significant differences between males and females were also found in PCSA for the popliteus (p = 0.005) and semimembranosus (p = 4.1E-05) muscles. There were no significant differences in fiber length, overall muscle length (with tendon removed), age, and orientation. CONCLUSION: Further consideration should be given to include the popliteus muscle as a dynamic entity in the knee given its mechanical properties, trajectory, and prior biomechanical evidence showing when and how it is activated. The present study provides data that may shape future directions of research and treatment with regard to posterolateral corner injuries and ligamentous balancing of the knee.

Diagnostic capability of dynamic ultrasound evaluation of supination-external rotation ankle injuries: a cadaveric study.

BACKGROUND: Ankle syndesmosis injuries are common and range in severity from subclinical to grossly unstable. Definitive diagnosis of these injuries can be made with plain film radiographs, but are often missed when severity or image quality is low. Computed tomography (CT) and magnetic resonance imaging (MRI) can provide definitive diagnosis, but are costly and introduce the patient to radiation when CT is used. Ultrasonography may circumvent many of these disadvantages by being inexpensive, efficient, and able to detect injuries without radiation exposure. The purpose of this study was to evaluate the ability of ultrasonography to detect early stage supination-external rotation (SER) ankle syndesmosis injuries with a dynamic external rotational stress test. METHODS: Nine, all male, fresh frozen specimens were secured to an ankle rig and stress tested to 10 Nm of external rotational torque with ultrasonography at the tibiofibular clear space. The ankles were subjected to syndesmosis ligament sectioning and repeat stress measurements of the tibiofibular clear space at peak torque. Stress tests and measurements were repeated three times and averaged and analyzed using a repeated one-way analysis of variance (ANOVA). There were six ankle injury states examined including: Intact State, 75% of AITFL Cut, 100% of AITFL Cut, Fibula FX - Cut 8 cm proximal, 75% PITFL Cut, and 100% PITFL Cut. RESULTS: Dynamic external rotation stress evaluation using ultrasonography was able to detect a significant difference between the uninjured ankle with a tibiofibular clear space of 4.5 mm and the stage 1 complete injured ankle with a clear space of 6.0 mm (P < .02). Additionally, this method was able to detect significant differences between the uninjured ankle and the stage 2-4 injury states. CONCLUSION: Dynamic external rotational stress evaluation using ultrasonography was able to detect stage 1 Lauge-Hansen SER injuries with statistical significance and corroborates criteria for diagnosing a syndesmosis injury at ≥6.0 mm of tibiofibular clear space widening.

Protecting the PCL During Total Knee Arthroplasty Using a Bone Island Technique.

BACKGROUND: Prior studies have shown that the posterior cruciate ligament (PCL) may be partially resected during cruciate retaining (CR) total knee arthroplasty (TKA) using highly experienced hands and standard surgical technique; therefore, proper surgical technique is aimed at preservation and balance of the PCL during CR TKA. The central objective of this study is to evaluate the effectiveness of a simple surgical technique to prevent PCL damage during performance of a CR TKA. METHODS: Sixty embalmed cadaver specimens were randomized into 2 groups, experimental and control. The control group consisted of standard tibial resection without the use of an osteotome. The experimental group utilized an osteotome in addition to standard technique to preserve a bone island anterior to the tibial attachment of the PCL. RESULTS: In the control group, PCL damage was noted in 73% (22/30) of specimens. In the experimental group, where an osteotome was used, PCL damage was found in 23% (7/30) of specimens. The use of an osteotome was found to have an absolute risk reduction of 50% when compared to the control group which did not use an osteotome to protect the PCL. CONCLUSION: In the setting of minimal surgical experience, the use of an osteotome to preserve the PCL during CR TKA by forming a bone island was found to be an effective means of protecting the PCL over standard technique. In addition, standard technique with the use of a Y-shaped PCL retractor was found to provide questionable protection to the PCL.

Effect of Posterior Tibial Slope on Flexion and Anterior-Posterior Tibial Translation in Posterior Cruciate-Retaining Total Knee Arthroplasty.

Reduced posterior tibial slope (PTS) and posterior tibiofemoral translation (PTFT) in posterior cruciate-retaining (PCR) total knee arthroplasty (TKA) may result in suboptimal flexion. We evaluated the relationship between PTS, PTFT, and total knee flexion after PCR TKA in a cadaveric model. We performed a balanced PCR TKA using 9 transfemoral cadaver specimens and changed postoperative PTS in 1° increments. We measured maximal flexion and relative PTFT at maximal flexion. We determined significant changes in flexion and PTFT as a function of PTS. Findings showed an average increase in flexion of 2.3° and average PTFT increase of 1mm per degree of PTS increase when increasing PTS from 1° to 4° (P<.05). Small initial increases in PTS appear to significantly increase knee flexion and PTFT.

One-bead, one-compound peptide library sequencing via high-pressure ammonia cleavage coupled to nanomanipulation/nanoelectrospray ionization mass spectrometry.

Biological screening of one-bead, one-compound (OBOC) combinatorial peptide libraries is routinely carried out with the peptide remaining bound to the resin bead during screening. After a hit is identified, the bead is isolated, the peptide is cleaved from the bead, and its sequence is determined. We have developed a new technique for cleavage of peptides from resin beads whereby exposure of a 4-hydroxymethyl benzoic acid (HMBA)-linked peptide to high-pressure ammonia gas led to efficient cleavage in as little as 5min. Here we also report a new method of extracting peptide from individual library beads for its introduction into a mass spectrometer that uses nanomanipulation combined with nanoelectrospray ionization mass spectrometry (NSI MS). Single beads analyzed by nanomanipulation/NSI MS were found to give identical MS results to those of bulk samples. Detection of 18 unique cleaved peptides 1 to 8 amino acids in length, and sequencing of 14 different peptide sequences 4 to 8 amino acids in length, was demonstrated on a combination of bulk samples and ones from individual beads of an OBOC library. The method was highly reproducible, with 100% of attempts to extract peptide resulting in high-quality MS data. This new collection of techniques allows rapid, reliable, environmentally responsible sequencing of hit beads from combinatorial peptide libraries.