Intra-observer reliability study of lumbar segmental measurements utilizing ultrasonography.

Background: Spinal Manipulative Therapy (SMT) benefits LBP patients, but its mechanism is not well documented. One hypothesis indicates that SMT restores interspinal movements. Ultrasound measurement (UM) of spinous process separation (SPS) assesses the intersegmental movements. Methods: We used the test-retest reliability of UM between the L3, L4, L5, and S1 spinous processes on fifteen asymptomatic volunteers while lying prone on a chiropractic table. The participants then walked around for over 5 minutes, and ultrasound images were reperformed prone. UM identified the tips of the spinous processes and distances between L3-L4, L4-L5, and L5-S1. Reliability was assessed using intra-class correlation coefficient (ICC). Results: ICC values of SPS measurements were 0.982 for L3-L4, 0.992 for L4-L5, and 0.997 for L5-S1. Rootmean square difference between the two measures were 0.35mm for L5-S1, 0.36mm for L4-L5, and 0.57mm for L3-L4. Conclusions: This study found UM to be reliable in measuring interspinous distance.

Étude de la fiabilité intra-observateur des mesures segmentaires lombaires par échographie. Contexte: La thérapie par manipulation vertébrale (TMV) est bénéfique pour les patients souffrant de lombalgie, mais son mécanisme n'est pas bien établi. L'une des hypothèses est que la TMV rétablit les mouvements intervertébraux. La mesure par échographie (UM) de la séparation de l'apophyse épineuse évalue les mouvements intersegmentaires. Méthodologie: Nous avons utilisé la fiabilité de testretest de l'UM entre les apophyses épineuses L3, L4, L5 et S1 sur quinze bénévoles asymptomatiques en position couchée sur une table de chiropratique. Les participants ont ensuite marché pendant plus de 5 minutes et les images échographiques ont été refaites en position couchée. L'UM a permis de repérer les extrémités des apophyses épineuses et de déterminer les distances entre L3-L4, L4-L5 et L5-S1. La fiabilité a été évaluée à l'aide du coefficient de corrélation intraclasse (CCI). Résultats: Les valeurs CCI des mesures de la séparation de l'apophyse épineuse étaient de 0,982 pour L3-L4, 0,992 pour L4-L5 et 0,997 pour L5-S1. La différence quadratique moyenne entre les deux mesures était de 0,35 mm pour L5-S1, 0,36 mm pour L4-L5 et 0,57 mm pour L3-L4. Conclusions: Cette étude a montré que l'UM était fiable pour mesurer la distance interépineuse.

High-velocity, low-amplitude spinal manipulation training of prescribed forces and thrust duration: A pilot study.

OBJECTIVE: High-velocity, low-amplitude spinal manipulation (HVLA-SM) may generate different therapeutic effects depending on force and duration characteristics. Variability among clinicians suggests training to target specific thrust duration and force levels is necessary to standardize dosing. This pilot study assessed an HVLA-SM training program using prescribed force and thrust characteristics. METHODS: Over 4 weeks, chiropractors and students at a chiropractic college delivered thoracic region HVLA-SM to a prone mannequin in six training sessions, each 30 minutes in duration. Force plates embedded in a treatment table were used to measure force over time. Training goals were 350 and 550 Newtons (N) for peak force and ≤150 ms for thrust duration. Verbal and visual feedback was provided after each training thrust. Assessments included 10 consecutive thrusts for each force target without feedback. Mixed-model regression was used to analyze assessments measured before, immediately following, and 1, 4, and 8 weeks after training. RESULTS: Error from peak force target, expressed as adjusted mean constant error (standard deviation), went from 107 N (127) at baseline, to 0.2 N (41) immediately after training, and 32 N (53) 8 weeks after training for the 350 N target, and 63 N (148), -6 N (58), and 9 N (87) for the 550 N target. Student median values met thrust duration target, but doctors' were >150 ms immediately after training. CONCLUSION: After participation in an HVLA-SM training program, participants more accurately delivered two prescribed peak forces, but accuracy decreased 1 week afterwards. Future HVLA-SM training research should include follow-up of 1 week or more to assess skill retention.

Clinician proficiency in delivering manual treatment for neck pain within specified force ranges.

BACKGROUND CONTEXT: Neck pain is a common musculoskeletal complaint responsive to manual therapies. Doctors of chiropractic commonly use manual cervical distraction, a mobilization procedure, to treat neck pain patients. However, it is unknown if clinicians can consistently apply standardized cervical traction forces, a critical step toward identifying an optimal therapeutic dose. PURPOSE: To assess clinicians' proficiency in delivering manually applied traction forces within specified ranges to neck pain patients. STUDY DESIGN: An observational study nested within a randomized clinical trial. SAMPLE: Two research clinicians provided study interventions to 48 participants with neck pain. OUTCOME MEASURES: Clinician proficiency in delivering cervical traction forces within three specified ranges (low force, less than 20 N; medium force, 21-50 N; and high force 51-100 N). METHODS: Participants were randomly allocated to three force-based treatment groups. Participants received five manual cervical distraction treatments over 2 weeks while lying prone on a treatment table instrumented with force sensors. Two clinicians delivered manual traction forces according to treatment groups. Clinicians treated participants first without real-time visual feedback displaying traction force and then with visual feedback. Peak traction force data were extracted and descriptively analyzed. RESULTS: Clinicians delivered manual cervical distraction treatments within the prescribed traction force ranges 75% of the time without visual feedback and 97% of the time with visual feedback. CONCLUSIONS: This study demonstrates that doctors of chiropractic can successfully deliver prescribed traction forces while treating neck pain patients, enabling the capability to conduct force-based dose response clinical studies.

Training and certification of doctors of chiropractic in delivering manual cervical traction forces: Results of a longitudinal observational study.

Objective : Doctors of chiropractic (DCs) use manual cervical distraction to treat patients with neck pain. Previous research demonstrates variability in traction forces generated by different DCs. This article reports on a training protocol and monthly certification process using bioengineering technology to standardize cervical traction force delivery among clinicians. Methods : This longitudinal observational study evaluated a training and certification process for DCs who provided force-based manual cervical distraction during a randomized clinical trial. The DCs completed a 7-week initial training that included instructional lectures, observation, and guided practice by a clinical expert, followed by 3 hours of weekly practice sessions delivering the technique to asymptomatic volunteers who served as simulated patients. An instrument-modified table and computer software provided the DCs with real-time audible and visual feedback on the traction forces they generated and graphical displays of the magnitude of traction forces as a function of time immediately after the delivery of the treatment. The DCs completed monthly certifications on traction force delivery throughout the trial. Descriptive accounts of certification attempts are provided. Results : Two DCs achieved certification in traction force delivery over 10 consecutive months. No certification required more than 3 attempts at C5 and occiput contacts for 3 force ranges (0-20 N, 21-50 N, and 51-100 N). Conclusions : This study demonstrates the feasibility of a training protocol and certification process using bioengineering technology for training DCs to deliver manual cervical distraction within specified traction force ranges over a 10-month period.

Real-time force feedback during flexion-distraction procedure for low back pain: A pilot study.

A form of chiropractic procedure known as Cox flexion-distraction is used by chiropractors to treat low back pain. Patient lies face down on a specially designed table having a stationery thoracic support and a moveable caudal support for the legs. The Doctor of Chiropractic (DC) holds a manual contact applying forces over the posterior lumbar spine and press down on the moving leg support to create traction effects in the lumbar spine. This paper reports on the development of real-time feedback on the applied forces during the application of the flexion-distraction procedure. In this pilot study we measured the forces applied by experienced DCs as well as novice DCs in using this procedure. After a brief training with real-time feedback novice DCs have improved on the magnitude of the applied forces. This real-time feedback technology is promising to do systematic studies in training DCs during the application of this procedure.

Une forme de procédure chiropratique connue sous le nom de flexion-distraction Cox est employée par les chiropraticiens dans le traitement de la lombalgie. Le patient se couche sur le ventre sur une table spécialement conçue, qui comporte un support thoracique stationnaire et un support caudal mobile pour les jambes. Le docteur en chiropratique (DC) maintient un contact manuel en appliquant une force sur la colonne lombaire postérieure, et appuie sur le support mobile pour les jambes afin de créer un effet de traction dans la colonne lombaire. Le présent article se veut un rapport sur le développement d'une rétroaction en temps réel au sujet des forces appliquées au cours de l'utilisation de la procédure de flexion-distraction. Dans cette étude pilote, nous avons mesuré les forces appliquées par des DC ayant de l'expérience et des DC débutants pendant l'application de cette procédure. Après une brève formation avec rétroaction en temps réel, les DC débutants s'étaient améliorés relativement à la magnitude des forces appliquées. Cette technologie de rétroaction en temps réel est prometteuse pour la réalisation d'études systématiques sur la formation des DC durant l'application de cette procédure.

Instantaneous rate of loading during manual high-velocity, low-amplitude spinal manipulations.

OBJECTIVE: The objective of this study was to determine the instantaneous rate of loading during manual high-velocity, low-amplitude spinal manipulations (HVLA SMs) in the lumbar and thoracic regions and compare to the average rates of loading. METHODS: Force-time profiles were recorded using a hand force transducer placed between the hand of a doctor of chiropractic and the subject's back during 14 HVLA SM thrusts on asymptomatic volunteers while 3 doctors of chiropractic delivered the spinal manipulations. Doctors also delivered 36 posterior to anterior thoracic manipulations on a mannequin. Data were collected at a sampling rate of 1000 Hz using Motion Monitor software. Force-time profile data were differentiated to obtain instantaneous rates of loading. The data were reduced using a custom-written MathCad program and analyzed descriptively. RESULTS: The instantaneous rates of loading were 1.7 to 1.8 times higher than average rates of loading, and instantaneous rates of unloading were 2.1 to 2.6 times the average rates of unloading during HVLA SMs. Maximum instantaneous rates of loading occurred 102 to 111 milliseconds prior to peak load. Maximum instantaneous rates of unloading occurred 121 to 154 milliseconds after the peak load. These data may be useful for further understanding of HVLA SMs. CONCLUSIONS: The instantaneous rates of loading and where they occurred may be useful data for understanding and describing HVLA SMs.

Force-time profile differences in the delivery of simulated toggle-recoil spinal manipulation by students, instructors, and field doctors of chiropractic.

OBJECTIVES: The objectives of this study were to examine the force-time profiles of toggle recoil using an instrumented simulator to objectively measure and evaluate students' skill to determine if they become quicker and use less force during the course of their training and to compare them to course instructors and to field doctors of chiropractic (DCs) who use this specific technique in their practices. METHODS: A load cell was placed within a toggle recoil training device. The preload, speed, and magnitude of the toggle recoil thrusts were measured from 60 students, 2 instructors, and 77 DCs (ie, who use the toggle recoil technique in their regular practice). Student data were collected 3 times during their toggle course (after first exposure, at midterm, and at course end.) RESULTS: Thrusts showed a dual-peak force-time profile not previously described in other forms of spinal manipulation. There was a wide range of values for each quantity measured within and between all 3 subject groups. The median peak load for students decreased over the course of their class, but they became slower. Field doctors were faster than students or instructors and delivered higher peak loads. CONCLUSION: Toggle recoil thrusts into a dropping mechanism varied based upon subject and amount of time practicing the task. As students progressed through the class, speed reduced as they increased control to lower peak loads. In the group studies, field DCs applied higher forces and were faster than both students and instructors. There appears to be a unique 2-peak feature of the force-time plot that is unique to toggle recoil manipulation with a drop mechanism.

Effect of sampling rates on the quantification of forces, durations, and rates of loading of simulated side posture high-velocity, low-amplitude lumbar spine manipulation.

OBJECTIVE: Quantification of chiropractic high-velocity, low-amplitude spinal manipulation (HVLA-SM) may require biomechanical equipment capable of sampling data at high rates. However, there are few studies reported in the literature regarding the minimal sampling rate required to record the HVLA-SM force-time profile data accurately and precisely. The purpose of this study was to investigate the effect of different sampling rates on the quantification of forces, durations, and rates of loading of simulated side posture lumbar spine HVLA-SM delivered by doctors of chiropractic. METHODS: Five doctors of chiropractic (DCs) and 5 asymptomatic participants were recruited for this study. Force-time profiles were recorded during (i) 52 simulated HVLA-SM thrusts to a force transducer placed on a force plate by 2 DCs and (ii) 12 lumbar side posture HVLA-SM on 5 participants by 3 DCs. Data sampling rate of the force plate remained the same at 1000 Hz, whereas the sampling rate of the force transducer varied at 50, 100, 200, and 500 Hz. The data were reduced using custom-written MATLAB (Mathworks, Inc, Natick, MA) and MathCad (version 15; Parametric Technologies, Natick, MA) programs and analyzed descriptively. RESULTS: The average differences in the computed durations and rates of loading are smaller than 5% between 50 and 1000 Hz sampling rates. The differences in the computed preloads and peak loads are smaller than 3%. CONCLUSIONS: The small differences observed in the characteristics of force-time profiles of simulated manual HVLA-SM thrusts measured using various sampling rates suggest that a sampling rate as low as 50 to 100 Hz may be sufficient. The results are applicable to the manipulation performed in this study: manual side posture lumbar spine HVLA-SM.

Paraspinal muscle function assessed with the flexion-relaxation ratio at baseline in a population of patients with back-related leg pain.

OBJECTIVE: The purpose of this study was to assess back muscle status at baseline in patients with back-related leg pain (BRLP) and to correlate those findings with baseline demographic and clinical factors. METHODS: Surface electromyography (EMG) and electromagnetic motion-tracking detected flexion-relaxation response in 135 patients with BRLP. Surface EMG electrodes were attached with standard skin preparation over the right and left paraspinal muscles at L3. Participants moved from upright standing into full forward flexion, rested flexed for 1 second, and returned to the upright position. A flexion-relaxation ratio (FRR) factor was calculated as the root mean square EMG amplitude during forward flexion divided by the activity at full flexion. RESULTS: High repeatability was found (intraclass correlation coefficient [ICC]([1,3]) = 0.94 and 0.86) between 3 cycles of assessment at the same session. Patients with BRLP exhibited low FRR values, indicating a loss of the flexion-relaxation response similar to that seen in low back pain patients. Patients with very low FRR had higher Roland-Morris Disability Questionnaire scores than the other patients, had increased incidence of straight leg raise test, and had decreased range and rate of forward flexion. CONCLUSIONS: A subgroup of patients with BRLP was identified with very low FRR who exhibited more disability and clinical findings and decreased motion. The use of the inverted FRR factor, expressing muscle activity at the fully flexed and resting position as a percentage of peak activity during flexion, provides more stable numerical behavior and another perspective on interpreting FRRs.

A randomized clinical trial and subgroup analysis to compare flexion-distraction with active exercise for chronic low back pain.

Many clinical trials on chiropractic management of low back pain have neglected to include specific forms of care. This study compared two well-defined treatment protocols. The objective was to compare the outcome of flexion-distraction (FD) procedures performed by chiropractors with an active trunk exercise protocol (ATEP) performed by physical therapists. A randomized clinical trial study design was used. Subjects, 18 years of age and older, with a primary complaint of low back pain (>3 months) were recruited. A 100 mm visual analogue scale (VAS) for perceived pain, the Roland Morris (RM) Questionnaire for low back function, and the SF-36 for overall health status served as primary outcome measures. Subjects were randomly allocated to receive either FD or ATEP. The FD intervention consisted of the application of flexion and traction applied to specific regions in the low back, with the aid of a specially designed manipulation table. The ATEP intervention included stabilizing and flexibility exercises, the use of modalities, and cardiovascular training. A total of 235 subjects met the inclusion/exclusion criteria and signed the informed consent. Of these, 123 were randomly allocated to FD and 112 to the ATEP. Study patients perceived significantly less pain and better function after intervention, regardless of which group they were allocated to (P<0.01). Subjects randomly allocated to the flexion-distraction group had significantly greater relief from pain than those allocated to the exercise program (P=0.01). Subgroup analysis indicated that subjects categorized as chronic, with moderate to severe symptoms, improved most with the flexion-distraction protocol. Subjects categorized with recurrent pain and moderate to severe symptoms improved most with the exercise program. Patients with radiculopathy did significantly better with FD. There were no significant differences between groups on the Roland Morris and SF-36 outcome measures. Overall, flexion-distraction provided more pain relief than active exercise; however, these results varied based on stratification of patients with and without radiculopathy and with and without recurrent symptoms. The subgroup analysis provides a possible explanation for contrasting results among randomized clinical trials of chronic low back pain treatments and these results also provide guidance for future work in the treatment of chronic low back pain.