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.

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.

Measurement of Lumbar Lordosis: A Comparison of 2 Alternatives to the Cobb Angle.

OBJECTIVE: The purpose of this study was to compare 2 alternative methods, the radiologic Harrison Posterior Tangent Method (HPTM) and the nonradiologic Spinal Mouse (SM), to the Cobb angle for measuring lumbar lordosis. METHODS: Sixteen participants with previously existing lateral lumbopelvic radiographs underwent nonradiographic lordosis assessment with a Spinal Mouse. Then 2 investigators analyzed each radiograph twice using the Harrison Posterior Tangent Method and Cobb angle. Correlations were analyzed between HPTM, the Cobb angle, and SM using the Spearman rank correlation coefficient; intraexaminer and interexaminer agreement were analyzed for HPTM and the Cobb angle using intraclass correlation coefficients. RESULTS: The HPTM correlated highly with the Cobb angle (Spearman ρ = 0.936, P < .001); SM had moderate to strong correlations with the Cobb angle (ρ = 0.737, P = .002) and HPTM (ρ = 0.707, P = .003). Intraexaminer and interexaminer agreement for the Cobb angle and HPTM were excellent (all intraclass correlation coefficients > 0.90). One participant had slight kyphosis according to HPTM and SM analyses (which consider the entire lumbar region), whereas the Cobb angle, based only on L1 and L5, reported mild lordosis for that participant. CONCLUSION: In this sample, HPTM measurements showed high correlation with the commonly used Cobb angle, but this method requires more time and effort, and normal values have not been established. The SM may be an alternative when radiographs are inappropriate, but it measures soft tissue contours rather than lordosis itself.

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.

On-Site Chiropractic Care as an Employee Benefit: A Single-Location Case Study.

OBJECTIVE: The purpose of this report is to describe the role of on-site chiropractic care in one corporate environment. METHODS: A part-time chiropractic practice that provides services to a single company on site, 1 day per week, is described. Most care is oriented toward "wellness," is paid for by the employer, and is limited only by the chiropractor's few weekly hours of on-site availability. With approval from the company, the authors conducted an absenteeism analysis after obtaining ethics approval and consent from employee-patients who received care between 2012 and 2014. Comparisons of absenteeism rates of the sample were compared with lost worktime rates from the US Bureau of Labor Statistics' Labor Force Statistics. RESULTS: Of 40 current employees, 35 used chiropractic services; 17 employee-patients met the inclusion criteria. The lost worktime rates of those using chiropractic services (0.72%, 0.55%, and 0.67%, for 2012, 2013, and 2014, respectively) were lower than corresponding rates from Labor Force Statistics (1.5%, 1.2%, and 1.1%). CONCLUSIONS: Absenteeism for the employee-patients was lower than equivalent national figures in this sample of workers. Though these results may or may not be related to the chiropractic care, these findings prompt further investigation into this relationship.

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.

Low Back Pain Response to Pelvic Tilt Position: An Observational Study of Chiropractic Patients.

OBJECTIVE: The aim of this study was to look for differences between patients with an increased pain response as compared with those with a decreased pain response. METHODS: Data were collected from consecutive new patients with lumbar or lumbopelvic pain in a chiropractic clinic. A pelvic tilt exercise was included in the initial examination, and pain response was noted. Analysis was made of pain and disability severity, as well as symptom location, chronicity, and other characteristics, before and after a course of chiropractic care. RESULTS: Patients with an increased pain response to pelvic tilt (n = 12) had higher levels of pain and disability at baseline than patients without (n = 34). There were no between-group differences in other aspects of their complaints; in age, sex, or body mass; or in the types of care they received (eg, manipulation, stretching, exercise instruction). On the average, both groups of patients showed improvement with chiropractic care, and there was no detectable difference in improvement between groups. CONCLUSIONS: This study found that patients experiencing pain in response to a pelvic tilt maneuver may have a poorer precare status than patients with a decreased pain response.

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.

Measurement of lumbar lordosis in static standing posture with and without high-heeled shoes.

OBJECTIVE: Some doctors and therapists believe that wearing high-heeled shoes causes increased lumbar lordosis and that this may be a cause of low back pain. The purpose of this study was to evaluate whether high-heeled shoes increase lumbar lordosis and to do so with more reliable methods and a larger sample size than used in previous studies. METHODS: Fifty participants from a chiropractic university were included in a test group (32 female and 18 male) and 9 in a control group (3 female and 6 male). A Spinal Mouse was used to measure lumbar lordosis in test participants barefoot and then again with 3- or 4-in high-heeled shoes after a 10-minute adaptation period of walking and sitting and standing while wearing the shoes. Reliability of the testing conditions was evaluated with 9 barefoot control participants before and after an identical adaptation period, and intra- and interexaminer reliability of Spinal Mouse measurements was tested by use of a wooden model built to mimic the proportions of a human spine. RESULTS: Both groups showed non-significant decreases in lordosis between the first and second scans (high heels: 23.4° to 22.8°, P = .17; control: 18.8° to 17.6°, P = .16). Scans of the wooden spine model were highly reliable (intra- and interexaminer intraclass correlation coefficients > .999). CONCLUSIONS: Consistent with most previous studies, high-heeled shoes did not affect lumbar lordosis in most people while standing. Future research could investigate the effect of shoes during dynamic conditions or identify affected subgroups.

Correlation between student performances on course level integrated clinical skills examinations and objective structured clinical examinations in a chiropractic college program.

PURPOSE: This retrospective study measured correlation of student performance between 2 objective structured clinical examinations (OSCEs) and an introductory integrated clinical skills course that preceded the OSCEs. The hypothesis was that there would be a strong, positive correlation between the earlier level examinations and the upper level OSCE, high enough that earlier examinations could be viewed as predictors of upper level OSCE performance. METHODS: Using student scores for 5 academic terms of upper level OSCEs for 2008-2009 (n = 208) and respective earlier scores, correlation coefficients were calculated for the upper level OSCE and Clinical Skills course, and upper and lower level OSCEs. Multiple linear regression analysis was used to evaluate how well the lower level OSCE and clinical skills scores, both as lone and combined independent variables, predicted the upper level OSCE scores. RESULTS: There was at least a moderate correlation between both sets of scores: r = .51 (p < .001) between upper level OSCE and clinical skills course, r = .54 (p < .001) between the upper and lower level OSCEs. A combination of clinical skills and lower level OSCE scores suggested a moderate prediction of upper level OSCE scores (R(2) = .38.) CONCLUSIONS: Correlations were found to be of at least a moderate level. According to linear regression analysis, a combination of the earlier scores was moderately predictive for the upper level OSCE. More research could be done to determine additional components of student performance.

The effect of high-heeled shoes on lumbar lordosis: a narrative review and discussion of the disconnect between Internet content and peer-reviewed literature.

OBJECTIVES: Some women complain of low back pain that they believe is due to wearing high-heeled shoes, and some clinicians seem to think the reason is that high-heeled shoes cause increased lumbar lordosis. This article examines Internet information aimed at the general public and presents a literature review of available research in this area. METHODS: The keywords high heels and high-heeled shoes, combined with the words lumbar, lordosis, and pelvic tilt, were used in an Internet search of Ask.com; in published literature searches of PubMed, MANTIS, CINAHL, Scopus, and ProceedingsFirst; and in searches for theses and dissertations of PapersFirst through June 2010. RESULTS: There are many Internet sites that support the belief that high-heeled shoes cause increased lordosis. However, published research for this topic mostly does not support this belief; but some mixed results, small subject groups, and questionable methods have left the issue unclear. CONCLUSIONS: It appears that some health care providers are offering advice about the effect of high-heeled shoes on lumbar lordosis that conflicts with most published research. However, the prevalence of such advice is unknown; and the published research is equivocal. Considering that both low back pain and the wearing of high heeled-shoes are common, clinicians could use some clearer guidance; this is an area that deserves further investigation.

Carpal tunnel syndrome and the "double crush" hypothesis: a review and implications for chiropractic.

Upton and McComas claimed that most patients with carpal tunnel syndrome not only have compressive lesions at the wrist, but also show evidence of damage to cervical nerve roots. This "double crush" hypothesis has gained some popularity among chiropractors because it seems to provide a rationale for adjusting the cervical spine in treating carpal tunnel syndrome. Here I examine use of the concept by chiropractors, summarize findings from the literature, and critique several studies aimed at supporting or refuting the hypothesis. Although the hypothesis also has been applied to nerve compressions other than those leading to carpal tunnel syndrome, this discussion mainly examines the original application - "double crush" involving both cervical spinal nerve roots and the carpal tunnel. I consider several categories: experiments to create double crush syndrome in animals, case reports, literature reviews, and alternatives to the original hypothesis. A significant percentage of patients with carpal tunnel syndrome also have neck pain or cervical nerve root compression, but the relationship has not been definitively explained. The original hypothesis remains controversial and is probably not valid, at least for sensory disturbances, in carpal tunnel syndrome. However, even if the original hypothesis is importantly flawed, evaluation of multiple sites still may be valuable. The chiropractic profession should develop theoretical models to relate cervical dysfunction to carpal tunnel syndrome, and might incorporate some alternatives to the original hypothesis. I intend this review as a starting point for practitioners, educators, and students wishing to advance chiropractic concepts in this area.

A suspected case of ulnar tunnel syndrome relieved by chiropractic extremity adjustment methods.

BACKGROUND: There has been little published about ulnar tunnel syndrome (UTS) as it relates to the practice of chiropractic, despite chiropractors' apparent interest in nerve compression syndromes and a growing trend toward providing chiropractic extremity care. This syndrome is not very common and could be mistaken for carpal tunnel syndrome by practitioners who are not aware of the differences. OBJECTIVE: To discuss the case of a patient with ulnar tunnel syndrome whose symptoms were resolved by chiropractic extremity adjustment. Clinical features A 45-year-old female patient complained of numbness in her little finger. Standard orthopedic testing procedures for the wrist and hand reproduced the symptom, but tests for the cervical spine and thoracic outlet region were negative. Intervention and outcome Care for this patient consisted of adjustment procedures directed to the wrist, primarily the hamate and pisiform articulations with the triquetrum. Her symptoms were resolved in 4 office visits, with corresponding improvement in examination findings. CONCLUSIONS: This case report represents what a patient could expect during a typical chiropractic treatment. The examination and the care given were simple and cost-effective but might not be sufficient for a more complicated or persistent case. The costs for the care in this case were borne solely by the patient and were affordable. Hard conclusions cannot be reached without more sophisticated diagnostic procedures, additional similar cases, and controlled research conditions.