Archive for category Spine

Abstract

OBJECTIVE:

The objectives of this study were to determine the ability of several commercial shockwave devices to achieve a desired thrust profile in a benchtop setting, determine the thrust profile in a clinical analog, and determine the influence of operator experience level on device performance.

INTERVENTION AND OUTCOME:

We conducted two different types of testing: (1) bench testing to evaluate the devices themselves, and (2) clinical equivalent testing to determine the influence of the operator.

CONCLUSIONS:

The results indicated a significant dependence of thrust output on the compliance of the test media. The Activator V-E device matched the ideal half-sine thrust profile to 94%, followed by the Impulse device (84%), the Activator IV/FS (74%), and the Activator II (48%). While most devices deviated from the ideal profile on the return path, the Impulse device exhibited a secondary peak. Moreover, the Activator V-E device provided evidence that the device performs consistently despite operator experience level.This has been a major concern in manual spinal manipulation. Based on our results, a hyper-flexible spine would receive a lower peak thrust force than a hypo-flexible spine at the same power setting. Furthermore, a hand-held operation further reduced the peak thrust force as it increased the system compliance. However, that influence was dissimilar for the different devices. Although controlled clinical trials are needed to determine the correlation between thrust profile and clinical outcome, already ongoing clinical studies indicate an improved patient satisfaction due to reduced treatment pain when devices are used with a thrust characteristic closer to an ideal sine wave.


Annals of Biomedical Engineering, Vol. 42, No. 12, December 2014 ( 2014) pp. 2524–2536 DOI: 10.1007/s10439-014-1115-4

Author information: Liebschner, Michael A. K.; Chun, Kwonsoo; Kim, Namhoon; and Ehni, Bruce

Department of Neurosurgery, Baylor College of Medicine, Houston, TX, USA; Research Service Line, Michael E. DeBakey VA Medical Center, Houston, TX, USA;  Exponent Failure Analysis, Houston, TX, USA;  Department of Pediatrics Cardiology, Baylor College of Medicine, Houston, TX, USA; and Neurosurgery Service Line, Michael E. DeBakey VA Medical Center, Houston, TX, USA

In Vitro Biomechanical Evaluation of Single Impulse and Repetitive

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ABSTRACT:

Objective:

To investigate the ability of the neurological examination to identify the specific level of a disc herniation in patients with sciatica and confirmed disc herniation.

Summary of Background Data:

Tests included in a neurological examination theoretically provide accurate diagnostic information about the level of the herniated disc. However, there is currently very little evidence about the diagnostic accuracy of individual tests or combinations of tests.

Methods:

The study included 283 patients with sciatica and confirmed disc herniation from a previous randomized controlled trial. The reference test for the current study was the MRI scan, reported for level of disc herniation. Index tests investigated were a neurologist’s overall impression of the level of disc herniation, individual neurological tests (e.g., sensation testing) and multiple test findings (i.e., the number of positive tests). The index tests were performed blinded to the MRI results. The diagnostic accuracy of the index tests in predicting herniations at the lower three lumbar discs was investigated using area under the curve (AUC), sensitivity and specificity.

Results:

None of the individual neurological tests from the clinical examination were highly accurate for identifying the level of disc herniation (AUC < 0.75). The outcome of multiple test findings was slightly more accurate but did not produce high sensitivity and specificity. The dermatomal pain location was generally the most informative individual neurological test. The overall suspected level of disc herniation rated by the neurologist after a full examination of the patient was more accurate than individual tests. At L4/5 and L5/S1 herniations the AUC for neurologist ratings was 0.79 and 0.80 respectively.

Conclusions:

The current study did not find evidence to support the accuracy of individual tests from the neurological examination in identifying the level of disc herniation demonstrated on MRI. A neurologist’s overall impression was moderately accurate in identifying the level of disc herniation.


Spine (Phila Pa 1976). 2011 May 15;36(11):E712-9. [PMID:21224761]

Author information: Hancock MJ, Koes B, Ostelo R, Peul W. Faculty of Health Sciences, University of Sydney, Australia.

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Abstract

Objective:

To examine the effect of spinal manipulation  on electromyographic (EMG) activity in areas of localized tight muscle  bundles of the low back.

Methods:

Surface EMG activity was collected from 16  participants in 2 chiropractic offices during the 5 to 10 minutes of the  treatment protocol. Electrodes were placed over the 2 sites of greatest  paraspinal muscle tension as determined by manual palpation. Spinal  manipulation was administered to 8 participants using Activator  protocol; the other 8 were treated using Diversified protocol.

Results:

Electromyographic activity decreased by at least  25% after treatment in 24 of the 31 sites that were monitored. There  was less than 25% change at 3 sites and more than 25% increase at 4  sites. Multiple distinct increases and decreases were observed in many  data plots.

Conclusions:

The results of this study indicate that  manipulation induces a virtually immediate change, usually a reduction,  in resting EMG levels in at least some patients with low back pain and  tight paraspinal muscle bundles. In some cases, EMG activity increased  during the treatment protocol and then usually, but not always,  decreased to a level lower than the pretreatment level.


J Manipulative Physiol Ther. 2005 Sep;28(7):465-71. [PMID:16182019]

Author information: DeVocht JW, Pickar JG, Wilder DG. Palmer Center for Chiropractic Research, Davenport, Iowa 52803, USA.

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Abstract

OBJECTIVE:

To quantify in vivo spinal motions and coupling patterns occurring in human subjects in response to mechanical force, manually assisted, short-lever spinal manipulative thrusts (SMTs) applied to varying vertebral contact points and utilizing various excursion (force) settings.

METHODS:

Triaxial accelerometers were attached to intraosseous pins rigidly fixed to the L1, L3, or L4 lumbar spinous process of 4 patients (2 male, 2 female) undergoing lumbar decompressive surgery. Lumbar spine acceleration responses were recorded during the application of 14 externally applied posteroanterior (PA) impulsive SMTs (4 force settings and 3 contact points) in each of the 4 subjects. Displacement time responses in the PA, axial (AX), and medial-lateral (ML) axes were obtained, as were intervertebral (L3-4) motion responses in 1 subject. Statistical analysis of the effects of facet joint (FJ) contact point and force magnitude on peak-to-peak displacements was performed. Motion coupling between the 3 coordinate axes of the vertebrae was examined using a least squares linear regression.

RESULTS:

SMT forces ranged from 30 N (lowest setting) to 150 N (maximum setting). Peak-to-peak ML, PA, and AX vertebral displacements increased significantly with increasing applied force. For thrusts delivered over the FJs, pronounced coupling was observed between all axes (AX-ML, AX-PA, PA-ML) (linear regression, R(2) = 0.35-0.52, P <.001), whereas only the AX and PA axes showed a significant degree of coupling for thrusts delivered to the spinous processes (SPs) (linear regression, R(2) = 0.82, P <.001). The ML and PA motion responses were significantly (P <.05) greater than the AX response for all SMT force settings. PA vertebral displacements decreased significantly (P <.05) when the FJ contact point was caudal to the pin compared with FJ contact cranial to the pin. FJ contact at the level of the pin produced significantly greater ML vertebral displacements in comparison with contact above and below the pin. SMTs over the spinous processes produced significantly (P <.05) greater PA and AX displacements in comparison with ML displacements. The combined ML, PA, and AX peak-to-peak displacements for the 4 force settings and 2 contact points ranged from 0.15 to 0.66 mm, 0.15 to 0.81 mm, and 0.07 to 0.45 mm, respectively. Intervertebral motions were of similar amplitude as the vertebral motions.

CONCLUSIONS:

In vivo kinematic measurements of the lumbar spine during the application of SMTs over the FJs and SPs corroborate previous spinous process measurements in human subjects. Our findings demonstrate that PA, ML, and AX spinal motions are coupled and dependent on applied force and contact point.


J Manipulative Physiol Ther. 2003 Nov-Dec;26(9):567-78. [PMID:14673406]

Author information: Keller TS, Colloca CJ, Gunzburg R. Department of Mechanical Engineering, University of Vermont, Burlington, USA.

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