Assessment of forces during side-posture adjustment with the use of a table-embedded force plate: Reference values for education.

OBJECTIVE: Force-sensing treatment tables are becoming more commonly used by chiropractic educational institutions. However, when a table-embedded force platform is the sole measurement method, there is little information available about what force-time values instructors and students should expect for side-posture spinal manipulative thrusts. The purpose of this report is to provide force-time values recorded with such a system during side-posture manipulation with human recipients. METHODS: Student volunteers were examined by and received lumbar or pelvic side-posture manipulation from experienced chiropractors who were diplomates of the Gonstead Clinical Studies Society. Forces were recorded using proprietary software of a Bertec force platform; force and time data were analyzed with a custom-programmed software tool in Excel. RESULTS: Seven doctors of chiropractic performed 24 thrusts on 23 student recipients. Preload forces, averaging 69.7 N, and thrust loading duration, averaging 167 milliseconds, were similar to previous studies of side-posture manipulation. Peak loads were higher than previous studies, averaging 1010.9 N. Other variables included prethrust liftoff force, times from thrust onset to peak force and peak load to resolution of thrust, and average rates of force loading and unloading. CONCLUSION: The values we found will be used for reference at our institution and may be useful to instructors at other chiropractic educational institutions, in the teaching of lumbar side-posture manipulation. A caveat is that the values of this study reflect multiple sources of applied force, not solely the force applied directly to the spine.

Spinal Kinematic Assessment of Chiropractic Side-Posture Adjustments: Development of a Motion Capture System.

OBJECTIVE: The purpose of this study was to develop a protocol and a data analysis system for the assessment of postures and movements of doctors of chiropractic during side-posture adjustments (SPAs), otherwise known as side-posture chiropractic spinal manipulation. METHODS: For this study, an experienced chiropractor performed Gonstead-style lumbar SPAs on 10 participants. We used an inertial measurement unit system to record spinal angular motions and analyzed data with a custom application written in Microsoft Excel. RESULTS: Data collection was successful for all trials. We identified postural angles at the time of set-up and thrust and maximum and minimum angles in a period centered on the thrust. All spinal regions of the chiropractor were flexed during the entire period; otherwise, movement patterns were characterized by biphasic wavelike motions, which begin before the time of the thrust and finish afterward. Within each region and plane of motion, patterns were qualitatively similar between participants, but time of thrust was not consistent within the patterns. There was a wide range of angular velocities, and the fastest was measured in the chiropractor's cervical and thoracic regions. CONCLUSION: In this study, we developed a protocol and a data analysis system for assessment of chiropractors' postures and movements during SPAs. The protocol may be useful to future investigators who wish to use similar methods for educational purposes or to examine the role of optimal or suboptimal movement patterns in occupational injuries of doctors of chiropractic.

Development of a mannequin lab for clinical training in a chiropractic program.

OBJECTIVE: Faced with COVID-19 safety protocols that severely limited the ability to conduct chiropractic technique instruction in the usual manner, our university invested the resources to develop a new mannequin lab for hands-on training, which would help supplement the loss of person-to-person contact. METHODS: Training mannequins could enable student learning of palpation and adjustment skills while avoiding close human-human contact. The university had developed a mannequin over the previous 4 years consisting of a full-sized human torso with individually movable and palpable vertebrae, pelvis, and thighs. In the mannequin, 64 pressure sensors are attached to particular vertebral and skeletal landmarks and provide feedback on palpation location and level of force applied. We assembled 3 teams to produce 20 copies of that mannequin for student use. RESULTS: Mannequins were produced in 7 weeks, and space was built out for a special lab. Faculty members are developing classroom procedures to introduce the mannequin to students, phase in the skills from static and motion palpation, and practice thrust performance. CONCLUSION: The production run was successful, and the resulting equipment, well-received by students and faculty. In addition to helping teach manual skills, the lab serves as a platform for educational research to test the efficacy of mannequin-based training protocols. With the pressure sensors on known locations along the spine, future research may be able to test the ability of students to identify and contact specific target locations for adjustive thrusts.

Angular Kinematics of Chiropractic Supine Cervical Spine Manipulation: Rotational Measures and Comparisons to Doctor and Recipient Perceptions.

OBJECTIVES: The primary purposes of this study were to measure axial rotation during supine cervical spinal manipulative therapy (cSMT) and to record recipients' and doctors' perceptions of rotational magnitudes. METHODS: Experienced doctors of chiropractic (DCs) provided supine cSMT and acted as recipients of cSMT. Participants who received SMT wore inertial measurement units attached to the forehead and sternum for motion capture. Afterward, recipients and DCs completed questionnaires asking about their perceptions of motion. Data were analyzed for magnitudes of axial rotation at peak thrust and correlations with patient and doctor perceptions. Secondary analyses included angular velocity, angular acceleration, and other kinematic variables. RESULTS: We recorded 23 SMT events with 14 DCs. Rotation at thrust peaks averaged 32.4° (17.4°). Doctors' and recipients' perceptions of rotation were higher than measured values 45% and 50% of the time, respectively. Maximum angular velocity and acceleration averaged 221.9°/s (124.9) and 4786.5°/s2 (2456.6), respectively. We found no correlation between perceptions and velocity or acceleration; doctors' perceptions had an inverse correlation with measurements. CONCLUSION: On average, we found rotation during supine cSMT to be 32°. Both DCs and SMT recipients overestimated rotation compared with actual measurements. These factors should be considered in discussions of rotation and SMT.

Assessing the feasibility of using an electronic records database system in use in a group of private chiropractic clinics for practice-based research.

OBJECTIVE: To explore the feasibility of collecting aggregated patient data from the electronic records of a group of private practices and to determine the suitability of the data for comparative effectiveness or other practice-based research (PBR). METHODS: Assess the type and quality of healthrelated variables contained in a commercially available electronic records system (Vitalogics) in use in consenting chiropractor's offices. Descriptively analyze baseline patient records to identify demographic variables, vital signs, case types and diagnoses. RESULTS: Of the 46,000 individual patient records that were analyzed, only a fraction had usable demographic data while more than half contained ICD-9 codes, including records for non-insurance case-types. None contained outcome variables. CONCLUSION: We did not find that the electronic record system we examined had the types of demographic and outcomes variables that would be useful for comparative effectiveness research. The addition of special fields to code chief complaint and health status indicators not typically included in an electronic records system would be most useful.

OBJECTIF: Examiner la possibilité de recueillir des macrodonnées de patients dans les dossiers électroniques d'un groupe de cliniques privées et déterminer leur utilité pour mener une recherche comparative d'efficacité ou mener d'autres recherches fondées sur la pratique. MÉTHODOLOGIE: Évaluer le type et la qualité des variables de santé contenus dans le logiciel de gestion de dossiers médicaux informatisés de Vitalogics en usage dans les cabinets des chiropraticiens consentants. Effectuer une analyse descriptive de dossiers de patients de référence pour trouver des variables démographiques, des signes vitaux, des cas types et des diagnostics. RÉSULTATS: Des 46 000 dossiers de patients examinés, seule une partie contenaient des données démographiques utiles alors que moins de la moitié contenaient les codes de la classification ICD-9, et des données sur des cas types non assurés. Aucun ne contenait de variables de résultats. CONCLUSION: À notre avis, le système de gestion de dossiers électroniques examinés ne fournit pas des types de variables démographiques et de variables de résultats qui seraient utiles pour mener une recherche comparative d'efficacité. L'ajout de champs spéciaux permettant de saisir le code du symptôme principal et des indicateurs de l'état de santé, ce qui d'habitude ne se trouve pas dans un logiciel de gestion de dossiers électroniques, s'avérerait très utile.

Mechanical properties of a thoracic spine mannequin with variable stiffness control.

OBJECTIVE: To test the posterior-to-anterior stiffness (PAS) of a new thoracic spine training simulator under different conditions of "fixation." METHODS: We constructed a thoracic spine model using plastic bones and ribs mounted in a wooden box, with skin and soft tissue simulated by layers of silicone and foam. The spine segment could be stiffened with tension applied to cords running through the vertebrae and ribs. We tested PAS at 2 tension levels using a custom-built device to apply repetitive loads at the T6 spinous process (SP) and over adjacent soft tissue (TP) while measuring load and displacement. Stiffness was the slope of the force-displacement curve from 55 to 75 N. RESULTS: Stiffness in the unconstrained (zero tension) condition over the SP averaged 11.98 N/mm and 6.72 N/mm over the TP. With tension applied, SP stiffness increased to 14.56 N/mm, and TP decreased to 6.15 N/mm. CONCLUSION: Thoracic model compliance was similar to that reported for humans. The tension control system increased stiffness by 21.3% only over the SP. Stiffness over the TP was dominated by the lower stiffness of the thicker foam layer and did not change. The mannequin with these properties may be suitable for use in manual training of adjusting or PAS testing skills.

Chronic Progressive External Ophthalmoplegia and Bilateral Vestibular Hypofunction: Balance, Gait, and Eye Movement Before and After Multimodal Chiropractic Care: A Case Study.

OBJECTIVE: The purpose of this report is to describe care of a patient with chronic progressive external ophthalmoplegia and bilateral vestibular hypofunction. CLINICAL FEATURES: A 66-year-old patient presented with limited eye movement and mild ptosis, which led to a diagnosis of chronic progressive external ophthalmoplegia. Rotary chair testing suggested vestibular involvement. Other symptoms included dizziness, problems with balance, and chronic stiffness in his cervical and thoracic regions. He had anxiety about loss of function and limited exercise habits because of fear of falling. Examination methods included balance assessment, kinetic aspects of walking, and videonystagmography. INTERVENTION AND OUTCOME: He had already begun regular practice of vestibular rehabilitation exercises before receiving 18 sessions of manual and instrument-assisted chiropractic manipulation, along with mobilization, stretching, and transverse massage, over 37 weeks. In addition to self-reported improvements, there was substantially decreased postural sway during balance assessment and there were small improvements in eye movement, ptosis, and walking. CONCLUSION: This patient showed improvements in balance, eye movements, and walking while undergoing multimodal chiropractic care and practicing eye and balance exercises.

Walking Gait Before and After Chiropractic Care Following Fifth Metatarsal Fractures: A Single Case Kinetic and Kinematic Study.

OBJECTIVES: The purpose of this report is to describe the kinetic and kinematic analysis of walking gait following healed left proximal fifth metatarsal fractures. CLINICAL FEATURES: A 62-year-old female presented at a chiropractic clinic with concerns that recent metatarsal fractures had not fully resolved and reported abnormal gait due to pain and several weeks use of a "walking boot." The patient's walking gait was evaluated with a force-sensor treadmill and an inertial measurement unit motion capture system. Recordings were made before, at midpoint, and post-chiropractic care (11 visits total). Data were analyzed for spatio-temporal gait parameters, vertical ground reaction forces, and ranges of motion of the hip, knee, and ankle. INTERVENTION AND OUTCOME: Pre-care, the patient's self-rated disability in walking was 50 out of 80 on a Lower Extremity Functional Scale, which improved to 80 out of 80, post-care. Her self-selected preferred walking speed increased, as did step length, cadence, and single support time. Increased symmetry was seen in timing of peak ground reaction forces, stance phase percentages of loading and pre-swing, and ranges of motion for hip and knee flexion and extension. CONCLUSIONS: The patient recovered completely, and the post-injury kinematic and kinetic data allowed for quantification of gait patterns and changes in the clinical environment.

Changes in adjustment force, speed, and direction factors in chiropractic students after 10 weeks undergoing standard technique training.

OBJECTIVE: To assess the force profiles of high-velocity low-amplitude thrusts delivered to a mannequin on a force platform by novice students given only verbal instructions. METHODS: Student volunteers untrained in adjusting delivered a series of adjustments to a mannequin on a force platform. Participants performed 3 light, 3 normal, and 3 heavy thrusts on 5 listings specifying contact point, hand, and direction. Force profiles were analyzed for speed and amplitude, consistency, and force discrimination. Two recording sessions occurred 10 weeks apart. RESULTS: Sixteen participants (11 females, 5 male) completed the study. Peak forces ranged from 880 to 202 N for heavy thrusts and 322- to 66 N for light thrusts. Thrust rate was from 8.1 to 1.8 Newtons per millisecond. Average coefficients of variability (CV = STD/mean) at each load level (initial/final) were heavy: 17%/15%; normal: 16%/15%; and light: 20%/20%, with 0 as ideal. A force ratio measured students' abilities to distinguish thrust magnitude. The heavy/normal ratio (initial/final) was 1.35/1.39, and the light/normal ratio was 0.70/0.67. CONCLUSIONS: At this point, without force feedback being used in the classroom, novice students can produce thrusts that look like those of their teachers and of experienced practitioners, but they may not produce similar speed and force values. They are consistent within and between sessions and can discriminate between light and heavy loads. A natural next step in our educational research will be to measure adjustment factors on more experienced cohorts of students with and without the presence of force-feedback training apparatus.

Thrust Magnitudes, Rates, and 3-Dimensional Directions Delivered in Simulated Lumbar Spine High-Velocity, Low-Amplitude Manipulation.

OBJECTIVES: The purpose of this study was to measure faculty performance of simulated spinal manipulation on a mannequin to help identify teaching standards. METHODS: We measured 3-dimensional transmitted loads using a force plate mounted in the table. Thrusts were delivered through a compliant, jointed mannequin by faculty members along predefined "listings" as taught in lumbopelvic technique courses. RESULTS: Eleven chiropractic faculty members participated, delivering 9 thrusts at 3 loads (light, moderate, and heavy) along 9 different prone and side-posture listings, totaling 81 thrusts per participant. Single-hand Gonstead-style thrusts had variability in magnitude across participants and loads: light thrusts averaged 365 N (95% confidence interval [CI] 327-402), moderate thrusts 454 N (421-487), and heavy thrusts 682 N (623-740). All faculty members could easily distinguish the loads within their performances, but there was some crossover of load levels between participants. Thrust rates averaged 3.55 N/ms (95% CI 3.29-3.82). The dominant vector of prone thrusts was in the z direction (vertically downward), but side-to-side and inferior-to-superior vector components occurred. CONCLUSION: Faculty member performance of simulated spinal manipulation indicated that they are able to control the thrust magnitude and rate as well as direction. In this sample, there was significant variability in peak loads between participants, which needs to be considered in student learning standards. These findings may be useful in translating the understanding of force characteristics to the technique teaching lab.

Establishing force and speed training targets for lumbar spine high-velocity, low-amplitude chiropractic adjustments.

OBJECTIVE: We developed an adjusting bench with a force plate supporting the lumbar portion to measure loads transmitted during lumbar manual adjustment. It will be used to provide force-feedback to enhance student learning in technique labs. The study goal is to define the learning target loads and speeds, with instructors as expert models. METHODS: A total of 11 faculty members experienced in teaching Gonstead technique methods performed 81 simulated adjustments on a mannequin on the force plate. Adjustments were along 9 lumbopelvic "listings" at 3 load levels: light, normal, and heavy. We analyzed the thrusts to find preload, peak load, duration, and thrust rate. RESULTS: Analysis of 891 thrusts showed wide variations between doctors. Peak loads ranged from 100 to 1400 N. All doctors showed clear distinctions between peak load levels, but there was overlap between high and low loads. Thrust rates were more uniform across doctors, averaging 3 N/ms. CONCLUSION: These faculty members delivered a range of thrusts, not unlike those seen in the literature for high velocity, low amplitude manipulation. We have established at least minimum force and speed targets for student performance, but more work must be done to create a normative adjustment to guide refinement of student learning.