The authors have no acknowledgements.

Full approvals from the Department of Orthopaedic Surgery at the University of Tuebingen and the Ethics Committee at the University Hospital Tuebingen were obtained before the commencement of the study. Written informed consent was received from all subjects before their participation.
1. Patient Recruiting and Preparation
<ol>
	<li>Recruit a subject, aged more than 18 years, who suffers from lumbar back pain and degenerative disc disease.
	<ol>
		<li>Gather all relevant data as back pain related patient history, results from magnetic resonance imaging, current pain medication and history of physiotherapy.</li>
		<li>Perform an orthopedic physical examination to identify the origin of the lumbar back pain looking for tender pressure points, test lateral flexion and trunk inclination and extension, and perform the straight leg raise. For differential diagnosis also test the hip joint for example for flexion, extension and rotation. 
		NOTE: 30 subjects and 28 reference subjects were used for the original study.</li>
	</ol>
	</li>
	<li>Rule out that the subject has a neurologic deficit of the lower limbs that requires immediate surgery by physical examination of each of the key muscles. 
	NOTE: A deficit in the sensorimotor system of the lower limb of less than grade 3/5 (Janda&#39;s classification) should not be included in this study.</li>
	<li>Ensure that the subject presents with normal walking ability and does not show any acute neoplastic or infectious pathology of the spine. 
	NOTE: The neoplastic or infectious pathology of the spine will be visible in the magnetic resonance imaging.</li>
	<li>Schedule the subject for spinal surgery.</li>
	<li>Ask all subjects to sign an informed consent for participating in the study.</li>
	<li>Schedule measurement dates for the following experimental setup (see 1.7, 1.8, 1.9., 1.10.) with the subject.</li>
	<li>Perform the first measurement one day prior to surgery.</li>
	<li>Perform the second measurement approximately seven days after surgery, when walking on ward-level is regained.</li>
	<li>Schedule and perform the third measurement three-months postoperatively.</li>
	<li>Schedule and perform the fourth measurement one-year postoperatively. 
	NOTE: During each examination ask the subject to complete the Oswestry Disability Index (ODI) 34 questionnaire and to indicate their usual value on the Numeric Pain Rating Scale (NRS) 35.</li>
	<li>Perform the gait and posture analysis with the subject on each visit following the subsequent instructions under section 2 of the protocol.</li>
</ol>
2. Experimental Design
<ol>
	<li>Questionnaires
	<ol>
		<li>Ask the subject to complete the Oswestry Disability Index (ODI) questionnaire and to indicate his or her usual value on the Numeric Pain Rating Scale (NRS).</li>
	</ol>
	</li>
	<li>Rasterstereographic analysis
	<ol>
		<li>Implement the measurement setup.
		<ol>
			<li>Use a device based on the principle of optical stereographic measuring that allows the detection of the specific anatomical landmark&#39;s vertebra prominens, the two lumbar dimples, and the sacrum point of the rima ani.</li>
			<li>Use an apparatus that estimates spine configuration on the Moir&#233; principle using a projector that projects a grid of light lines on the patient&#39;s back and contains a light-optical scanning camera. 
			&#8203;NOTE: Based on the principles of triangulation, the software analyzes the projected lines and generates a 3-D model of the patients&#39; surface (7,500 points).</li>
			<li>Build the measurement system with two main modules: the light projector unit that emits the projections of parallel lines and captures the reflections with a camera (15 Hz) and a personal computer with the manufacturer&#39;s analysis-software installed.</li>
			<li>Additionally, hang up a 2.5 m x 2 m piece of plain black cloth or similar that entirely covers the background of the image taken to improve the contrast.</li>
		</ol>
		</li>
		<li>Begin the measurement-process by asking the subject to undress from head down to the waist to expose all four needed anatomical landmarks: the neck with the vertebra prominens, the two lumbar dimples, and the sacrum point as the cranial end of the rima ani.</li>
		<li>Make sure that especially the caudal landmarks are also visible. This may require that the subject opens the trousers and lowers them a little.</li>
		<li>Let the subject stand freely and barefoot in a relaxed standard anatomical position with the feet shoulder-wide apart.</li>
		<li>Position the subject&#39;s front facing towards the wall with the black background while his or her back is targeted to the camera device.
		<ol>
			<li>Measure the distance from the subject&#39;s back surface to the camera device with a measuring tape, as it needs to be at 200 cm during all measurements.</li>
		</ol>
		</li>
		<li>Begin the measurement by clicking the button for the software&#39;s automatic landmark detection on screen while the subject stands freely, barefoot in a relaxed standard anatomical position with the feet shoulder-wide apart.
		<ol>
			<li>In case of a scanning error manually re-adjust the landmarks position according to the manufacturer&#39;s instructions provided with the software, so that they match their actual anatomic position (see step 2.2.2).</li>
		</ol>
		</li>
		<li>Set the system to a measurement time of 30 s. Due to the 15 Hz rate of the camera device about 450 images will be captured.</li>
		<li>Click Generate on the software panel and wait for the results. The software will calculate the average terminal values needed for further analysis.</li>
		<li>Let the subject rest for 120 s and subsequently step on the treadmill device.</li>
	</ol>
	</li>
</ol>
3. Treadmill Gait Analysis and (Optional) Plantar Pressure Measurements
<ol>
	<li>Use an instrumented treadmill with an integrated system containing capacitive pressure sensors under the belt to register gait parameters such as stride width, step length, stance phase and foot rotation.
	<ol>
		<li>Make sure to use a measuring system that contains of 10,200 miniature 0.85 cm x 0.85 cm capacitive pressure sensors on a mat of 150 cm x 50 cm, registering the exerted force at a rate of 120 Hz and which has a spatial resolution of the mat of 1.4 sensors/cm2.</li>
	</ol>
	</li>
	<li>At first, connect the treadmill and video camera to a commercial personal computer using the manufacturer&#39;s measurement software.</li>
	<li>Ask the subject to stand on the treadmill barefoot and with the pants rolled up to the knees.</li>
	<li>Attach a safety plug to the subject&#39;s shirt. 
	NOTE: The safety belt ensures measurement safety by an automatic shutdown of the treadmill, if the subject stumbles or is pushed too far back by the belt. In addition, the treadmill can be shut off via an emergency stop button or a cord.</li>
	<li>Use two lateral rail bars attached to the sides of the treadmill, to prevent the patient from falling off the treadmill in case of stumbling.</li>
	<li>Set the slope of the treadmill at 0% during the entire measurement. 
	NOTE: If necessary, the slope of the treadmill used in this study can be adjusted in a range from -2% to +15% in 0.5% increments, to simulate up-hill walking.</li>
	<li>To register the total load distribution on each foot, ask the subject to stand freely on the treadmill sensors thrice for 10 s. Then calculate the mean value of these three measurements.</li>
	<li>In the next step, when the treadmill is turned on, ask the subject to walk with normal gait and, as far as possible, not to hold on to the handrails. 
	NOTE: Walking on the treadmill without holding the handrail is recommended to obtain more dependable results and achieve higher reliability.</li>
	<li>Furthermore, advise the subject to walk between two adhesive tape markers you accurately attached beforehand on the surface of the treadmill to define the limits of the integrated sensor mat.</li>
	<li>After starting the treadmill, increase the speed in small increments of 0.1 km/h starting from 0.5 km/h until the subject&#39;s individual maximum well tolerable walking speed is reached. Ask the subject during the increase how he or she feels comfortable walking. 
	NOTE: The maximum well tolerable walking speed is reached when the subject has reached the highest walking speed with which he or she feels still comfortable walking. The belt speed can be upregulated in 0.1 km/h increments to a maximum speed of 22 km/h which thus even allows running measurements. The minimum speed of the treadmill is 0.5 km/h.</li>
	<li>For every subject measure two trials with a duration of 20 s. Let the subject rest for 60 s between the trials. 
	NOTE: The trial speed is specified by the individual walking speed determined in step 3.10.</li>
	<li>Film the subject&#39;s gait at the same time with a video camera from behind to allow visual correlation between the actual gait profile and the assessed parameters.</li>
	<li>Print the results displayed as a report through the software&#39;s interface at the end of the measurement. 
	NOTE: To further quantify foot pressure distribution during gait, the development of a software tool to subdivide the foot into different regions is necessary. For each region of interest pressures are registered from heel strike to toe-off during each gait cycle in N/cm&#178;. Eight distinct regions are defined: hindfoot, midfoot, first metatarsal head, second/third metatarsal head, fourth/fifth metatarsal head, hallux, second/third toe and fourth/fifth toe.</li>
</ol>
4. Experimental Design - Statistical Analysis
<ol>
	<li>Analyze the data obtained in step 2.2.8 and 3.13 using commercially available statistical software (Table of Materials). Import the data to the software by clicking Import.
	<ol>
		<li>Assess normality for the data obtained in step 2.2.8 and 3.13 by using histograms, the Shapiro-Wilk or Kolmogorov-Smirnoff test depending on the sample-size, and equality of variances by using the Levene test.</li>
		<li>Present data as mean (standard deviation) or median (minimum-maximum), depending on normality.</li>
		<li>Present categorical variables as relative or absolute frequencies.</li>
		<li>For treadmill variables organize each patient&#39;s bilateral data into major and minor values and calculate their absolute differences as a parameter for gait symmetry.</li>
		<li>For demographic characteristics use the Kruskal-Wallis test, chi-squared test, Friedman test, Wilcoxon test, and Tukey test, depending on normality.</li>
		<li>Calculate correlations between the measurement changes and changes in the patient-reported outcome measures between different time-points using Kendall&#39;s tau.</li>
		<li>Calculate NRS values as a percent of the initial value.
		<ol>
			<li>When grouping improvement on the Numeric Pain Rating Scale (NRS) ordinally, consider &#62;75% an excellent, 30-74% a moderate, and &#60;30% as no improvement. 
			NOTE: Since it is impossible to distinguish those patients with actual pain improvement &#60;30% accompanied by also functional improvement from those with improvement just due to a placebo effect (which can reach up to 30% improvement) where we would not expect functional changes, we classified this group for study purposes as &#34;no improvement&#34;35,36.</li>
		</ol>
		</li>
		<li>Interpret the Oswestry Disability Index (ODI) according the questionnaire&#39;s instructions.
		<ol>
			<li>Interpretation of the ODI: For each section, the total possible score is five. After all of the ten sections are completed by the patient, calculate the score as follows. Divide the selected total score by the total possible score (50) multiplied by 100 to obtain the final score in percent. For each section that is missed or not applicable the total score by which to divide is lowered by five. Interpretation of the final score: 0-20%: minimal disability, 21-40%: moderate disability, 41-60%: severe disability, 61-80%: crippled, 81-100%: exaggerating patient or bed-bound</li>
		</ol>
		</li>
	</ol>
	</li>
</ol>

The authors have nothing to disclose.

Perioperative surgical outcome-monitoring is a field that is subjectively shaped. First it is affected by the surgeon&#39;s experience and secondly by the patient&#39;s subjective perception registered by for example questionnaires which also reflect his or her psychological distress and illness behavior. Our presented procedure offers an approach that objectifies crucial parameters regarding functional outcome. The methodical setup presented in this manuscript allows high precision measurements of changes in posture and gait after lumbar surgery18,37,38,39,40, but it can also be applied for other surgical interventions of the musculoskeletal system.
The investigator has to be aware of some method-related pitfalls. The rasterstereographic analysis of the back profile is highly dependent on the precise selection of the anatomical landmarks. If chosen imprecisely, measurement and data calculation will be incorrect as well. In addition, the subject&#39;s back must be completely undressed. Even wires of a bra or long scalp hair could disturb the scanning process. As gait measurements are susceptible to limping as a result of a painful hip, knee or ankle joint, the tested subjects need to be well examined before inclusion in the study and also before each follow-up visit to ensure the results are relevant and in correlation to the alterations of the spine. Since both methods have a high intra- and interobserver reliability21,24,41,42, their use in every-day routine can be easily implemented. However, combining both measurement-techniques might make it difficult to keep track of the abundance of data and to interpret these findings in a justifiable time.
One limitation of the technique of back surface measurement in general is that, to date, the data in the literature mostly refer to radiologic parameters obtained from X-rays to interpret postoperative outcome24. Since &#8212; due to modality-specific limitations &#8212; the definition of parameters used to describe posture differs between rasterstereography and X-rays (for example thoracic angle: rasterstereography thoracic vertebrae 1 to 12, x-ray thoracic vertebrae 4 to 12) it is not yet possible to derive conclusions from absolute values obtained by rasterstereographic analysis. It is rather their changes in the perioperative course that are of interest. Presently this tool is thus best suited for longitudinal analyses.
Other objectifiable data, such as CT (computed tomography imaging) or MRI (magnetic resonance imaging), can help to technically evaluate postoperative outcome, but they only illustrate static anatomical details. In contrast to the non-invasive and radiation-free measurement techniques described in this protocol, these imaging techniques are not able to take function into consideration8,9,10.
Interestingly the changes for gait and posture in our study were not always related with the patients&#39; levels of pain. It thus appears that the postoperative dimension of function is not strictly associated with pain experience. The observed functional results are thus to be considered not contradictory but rather complementary to the patient related outcome measures. These measurements hence offer an additional dimension to critically evaluate postoperative outcome.
The evaluation of gait and posture is still a highly dynamic research field. We are confident that providing data about perioperative development of such functional parameters will improve our understanding of these conditions. In the long run, this may also help to further improve our surgical outcomes.
It is, therefore, important to apply the technique described in detail in this protocol and video on a broader scale to obtain more data about the functional parameters posture and gait in the perioperative course of musculoskeletal surgery.

This protocol provides instructions on how to objectively perform a functional posture and gait analysis of patients after lumbar spinal fusion surgery in contrast to subjective evaluation by the examiner or patient reported questionnaires. The setup consists of a high-resolution video rasterstereography for posture analysis, and a pressure-sensor equipped treadmill setup for gait analysis. Results obtained by these techniques from patients after lumbar fusion surgery are compared with subjectively reported pain relief.
Even if spinal surgery techniques and outcomes have vastly improved over the past years, the increase in procedures performed1,2 also leads to a rise in absolute numbers of patients dissatisfied with their individual postoperative results. For surgeons, it is thus crucial to identify those patients who will most likely benefit from surgery. The development of this skill is closely associated with the constant postoperative outcome evaluation and reevaluation of the initial indication for surgery.
To date, the postoperative outcome is mostly judged on subjective patient-reported levels of pain and function by questionnaires3,4,5. These questionnaires are, however, always subjectively affected and not only influenced by the objective physical abnormality but also by the patient&#39;s attitudes and beliefs, psychological distress, and illness behavior. Interestingly, even findings in X-ray, computed tomography or magnetic resonance imaging are prone to high inter- and intra-observer variability6,7,8,9,10. The additionally radiologic imaging, however, only offers a static technical evaluation of the surgery. There is a clear lack in means to objectively evaluate the functional outcome after spinal surgery.
A patient&#39;s posture and gait are generally supposed to be linked to the perceived level of pain and also to the overall quality of life11,12. Therefore, function can be considered one of the most important elements of postoperative outcome. The overall functional satisfaction of the patient seems to be associated with spinal alignment, kyphosis, lordosis and vertebral rotation13,14,15. As lumbar fusion surgery tries to restore the anatomical curvature of the spine and therefore to balance the muscles, the adaptation of posture is expected16. Restored lumbar lordosis is complementary with pain relief and thus result in the ability to walk painless.
The technique of back surface analysis goes back to the work of Takasaki and Meadows et al., as well as Drerup et al. from the late 1970s and 80s17,18,19,20,21. Based on the principle of triangulation, this technique presents a measurement inaccuracy of only 0.2 mm&#160;22. The technique is widely used and tested for the radiation free diagnosis and follow-up of patient with scoliosis23,24. In the context of evaluation of scoliosis patients, the setup showed good validity and an excellent intra- and interrater reliability25. An even more functional view on the patient offers the analysis of gait. A common technique to register the distinct parameters used to describe a patient&#39;s gait is a treadmill experimental setup. Thus stride width, step length, stance phase and foot rotation as well as pressure distribution for each foot can be measured at a very high precision26,27,28,29,30,31. Whereas patients with low back pain seem to use strategies to reduce the impact on the lumbar spine while walking, the treadmill setup offers the advantage to measure a patient&#39;s walk while keeping track of every single step32.
The hypothesis is that lumbar fusion surgery changes pathologic patterns in gait or posture and that these changes are in correlation with the detectable alleviation in the patient-reported outcome measure i.e., level of pain. The expected changes can be measured with video rasterstereography and treadmill gait analysis. The additional information about posture and gait can thus be compared with the overall functional status and satisfaction14,15,33.

<table><tbody><tr><td>Ergo-Run Medical&amp;nbsp;</td><td>Daum Electronic GmbH, Germany</td><td>NaN</td><td>NaN</td></tr><tr><td>formetric 4D</td><td>Diers International GmbH, Germany</td><td>NaN</td><td>NaN</td></tr><tr><td>IBM SPSS version 22</td><td>IBM Inc.</td><td>NaN</td><td>NaN</td></tr><tr><td>Matlab</td><td>MathWorks, Natick/MA, USA</td><td>NaN</td><td>NaN</td></tr><tr><td>Numeric Pain Rating Scale (NRS)</td><td>NaN</td><td>NaN</td><td>NaN</td></tr><tr><td>Oswestry Disability Index (ODI) questionnaire&amp;nbsp;</td><td>NaN</td><td>NaN</td><td>NaN</td></tr><tr><td>Video camera&amp;nbsp;</td><td>Canon MD 216, Japan</td><td>NaN</td><td>NaN</td></tr><tr><td>WinFDM-T software&amp;nbsp;</td><td>Version 2.0.39, zebris medical</td><td>NaN</td><td>NaN</td></tr><tr><td>Zebris medical system&amp;nbsp;</td><td>Zebris, Isny, Germany</td><td>NaN</td><td>NaN</td></tr></tbody></table>

evaluation of patients' posture and gait profile after lumbar fusion surgery by video rasterstereography and treadmill gait analysis

This protocol provides guidance on how to perform high resolution video rasterstereography and treadmill gait analysis on patients after lumbar fusion surgery to obtain results about altered variables of gait and posture. These observed changes can then be correlated with the patient-reported outcome measure of pain relief. The rasterstereographic device projects lines of parallel light onto the surface of the tested subject&#39;s back. The deformation of these lines is recognized by the device. From these data, a special software then generates a 3-D profile based on the principle of triangulation. With an inaccuracy of only 0.2 mm it can measure changes in posture at very high precision. Gait and stance parameters are recorded using a treadmill equipped with an electric sensor mat that contains 10,200 miniature force sensors in the registering zone under the belt. Initial walking speed on the treadmill is 0.5 km/h. Speed is then gradually increased by increments of 0.1 km/h until each subject reaches his or her individual maximum well tolerable walking speed. At this speed, parameters are recorded during a 20 s measurement interval. Subjects are tested barefoot and without holding a handrail. Among various other parameters, stride width, step length, stance phase and foot rotation are measured. Both methods used reportedly have a high intra- and inter-observer reliability. The advantage of these highly accurate techniques is that they offer an objective and very detailed perspective on changes in the patient&#39;s posture and gait. Due to the amount of data generated, these techniques are, however, not so much suitable for everyday routine use, but rather interesting to scientifically evaluate long term alterations in posture and gait in patients like for example after lumbar fusion surgery.

The representative results shown in this protocol come from a previous publication that has been published elsewhere26.
Rasterstereographic analysis 
The results of perioperative rasterstereographic analysis of patients who did suffer from chronic lumbar back pain and who were treated with lumbar fusion surgery (n = 59) showed no significant changes in trunk length at the 3 month follow-up in comparison to the preoperative measurements (459 (33) - 448 (40) mm; p = 0.313; Tukey test) (Figure 1A). We however noted a signi&#64257;cantly reduced kyphotic angle (vertebra prominens (VP) - thoracic spine vertebrae 12 (Th12), from 52&#176; to 43&#176;; p = 0.014; Tukey test) and lordotic angle (Th12 - dimple medium (DM), from 28&#176; to 11&#176;; p &#60; 0.001; Tukey test) at the &#64257;rst post-operative measurement when compared to the preoperative values (Figure 1B). No differences for the measurements of trunk inclination or lateral tilt were detected at any time point (Figure 1C, D).
Gait and stance analysis 
The treadmill gait measurements of the same patient cohort (n = 59) showed a significant reduction in cadence in the course from preoperatively to 3 months postoperatively (pre-OP to 7-days postoperatively: 98 (57-132) - 94 (43-119) steps/minute, p = 0.004; 3-months postoperatively: 91 (54-117) steps/minute, p = 0.006, Wilcoxon-test) (Figure 2A). Over the three postoperative months significant changes were detected for most spatiotemporal parameters (swing phase p = 0.01; stance phase p &#60; 0.001; foot rotation p = 0.001). However, no significant improvements were seen for the symmetry of swing phase (difference-major-minor value (DiffMJMn) 2 (0-8) - 1 (0-6) %), stance phase (DiffMJMn 2 (0-8) - 1 (0-6) %) or foot rotation (DiffMJMn 3 (0-10) - 3 (0-15)&#176;) (Figure 2B,C,D).
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/59103/59103fig1.jpg" /> 
Figure 1: Rasterstereographic results. Boxplots displaying measurement changes for (A) trunk length at the 3-months follow-up in comparison to the preoperative measurements (459 (33) - 448 (40)mm; p = 0.313; Tukey test), (B) Lordotic angle at the &#64257;rst postoperative measurement when compared to the preoperative values (thoracic spine vertebra 12 - dimple medium, from 28&#176; to 11&#176;; p &#60; 0.001; Tukey test), and (C-D) trunk inclination and lateral lilt over the course of one year (no significant difference). This figure has been adapted from reference26. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/59103/59103fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/59103/59103fig2.jpg" /> 
Figure 2: Gait and stance results. (A) Boxplots displaying a reduction in cadence from preoperatively over the postoperative course of 3 months (preoperatively to 7 days postoperatively: 98 (57-132) - 94 (43-119) steps/minute, p = 0.004; 3 months postoperatively: 91 (54-117) steps/minute, p = 0.006, Wilcoxon-test) and the preoperative, 7-days and 3-months postoperative treadmill results for (B) swing phase, (C) stance-phase and (D) foot-rotation grouped according to subjective pain relief after surgery in percentage (&#60;30%, 30-74%, &#62;75%). From preoperatively to 3-months postoperatively we detected significant changes for most spatiotemporal parameters (swing phase p = 0.01; stance phase p &#60; 0.001; foot rotation p = 0.001). No significant improvements were however observed with respect to their effect on gait symmetry (swing phase (difference-major-minor value (DiffMJMn) 2 (0-8) - 1 (0-6)%) stance phase (DiffMJMn 2 (0-8) - 1 (0-6)%, ), or foot rotation (DiffMJMn 3(0-10) - 3(0-15)&#176;)). This figure has been adapted from reference26. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/59103/59103fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Evaluation of Patients' Posture and Gait Profile After Lumbar Fusion Surgery by Video Rasterstereography and Treadmill Gait Analysis at JoVE.com

Evaluation of Patients' Posture and Gait Profile After Lumbar Fusion Surgery by Video Rasterstereography and Treadmill Gait Analysis

Here, we present a protocol to analyze the posture and the gait of patients after lumbar fusion surgery by means of high-resolution video rasterstereography and a treadmill equipped with an integrated sensor mat. Allowing critical functional postoperative evaluation on a less subjective level may enhance accuracy and reliability of indication for surgery.

This protocol provides guidance on how to perform high resolution video rasterstereography and treadmill gait analysis on patients after lumbar fusion ...

evaluation-patients-posture-gait-profile-after-lumbar-fusion-surgery

Nanyang Technological University

Research

JoVE Journal

Medicine

17.6K Views.  University Hospital Bonn. Met deze techniek zijn we eindelijk in staat om de gang en houding van patiënten na spinale chirurgie op een meer objectieve manier te analyseren, in vergelijking met de typische, veelgebruikte vragenlijsten. De techniek is volledig vrij van straling en eenmaal uitgevoerd haalbaar met matige inspanning. Bovendien zijn de goede validiteit en hoge intra- en interrater betrouwbaarheid grote voordelen van deze methode.Het functionele aspect van de gegevens die met deze techniek kunnen wor...

Video: Evaluation of Patients' Posture and Gait Profile After Lumbar Fusion Surgery by Video Rasterstereography and Treadmill Gait Analysis

Sit-to-stand-and-walk from 120% Knee Height: A Novel Approach to Assess Dynamic Postural Control Independent of Lead-limb

Individuals with sensorimotor pathology e.g., stroke have difficulty executing the common task of rising from sitting and initiating gait (sit-to-walk: STW). Thus, in clinical rehabilitation separation of sit-to-stand and gait initiation - termed sit-to-stand-and-walk (STSW) - is usual. However, a standardized STSW protocol with a clearly defined analytical approach suitable for pathological assessment has yet to be defined.
Hence, a goal-orientated protocol is defined that is suitable for healthy and compromised individuals by requiring the rising phase to be initiated from 120% knee height with a wide base of support independent of lead limb. Optical capture of three-dimensional (3D) segmental movement trajectories, and force platforms to yield two-dimensional (2D) center-of-pressure (COP) trajectories permit tracking of the horizontal distance between COP and whole-body-center-of-mass (BCOM), the decrease of which increases positional stability but is proposed to represent poor dynamic postural control.
BCOM-COP distance is expressed with and without normalization to subjects&#39; leg length. Whilst COP-BCOM distances vary through STSW, normalized data at the key movement events of seat-off and initial toe-off (TO1) during steps 1 and 2 have low intra and inter subject variability in 5 repeated trials performed by 10 young healthy individuals. Thus, comparing COP-BCOM distance at key events during performance of an STSW paradigm between patients with upper motor neuron injury, or other compromised patient groups, and normative data in young healthy individuals is a novel methodology for evaluation of dynamic postural stability.

Here, we present a novel protocol to measure positional stability at key events during the sit-to-stand-to-walk using the center-of-pressure to the whole-body-center-of-mass distance. This was derived from the force platform and three-dimensional motion-capture technology. The paradigm is reliable and can be utilized for the assessment of neurologically compromised individuals.

Individuals with sensorimotor pathology e.g., stroke have difficulty executing the common task of rising from sitting and initiating gait (sit-to-walk: ...

Behavior

Clinical-oriented Three-dimensional Gait Analysis Method for Evaluating Gait Disorder

Three-dimensional gait analysis (3DGA) is shown to be a useful clinical tool for the evaluation of gait abnormality due to movement disorders. However, the use of 3DGA in actual clinics remains uncommon. Possible reasons could include the time-consuming measurement process and difficulties in understanding measurement results, which are often presented using a large number of graphs. Here we present a clinician-friendly 3DGA method developed to facilitate the clinical use of 3DGA. This method consists of simplified preparation and measurement processes that can be performed in a short time period in clinical settings and intuitive results presentation to facilitate clinicians&#39; understanding of results. The quick, simplified measurement procedure is achieved by the use of minimum markers and measurement of patients on a treadmill. To facilitate clinician understanding, results are presented in figures based on the clinicians&#39; perspective. A Lissajous overview picture (LOP), which shows the trajectories of all markers from a holistic viewpoint, is used to facilitate intuitive understanding of gait patterns. Abnormal gait pattern indices, which are based on clinicians&#39; perspectives in gait evaluation and standardized using the data of healthy subjects, are used to evaluate the extent of typical abnormal gait patterns in stroke patients. A graph depicting the analysis of the toe clearance strategy, which depicts how patients rely on normal and compensatory strategies to achieve toe clearance, is also presented. These methods could facilitate implementation of 3DGA in clinical settings and further encourage development of measurement strategies from the clinician&#39;s point of view.

In this study, a clinician-friendly three-dimensional gait analysis method, which was designed to be performed in the rehabilitation clinic, is presented. The method consists of a simplified measurement method and intuitive figures to facilitate clinicians&#39; understanding of the results.

Three-dimensional gait analysis (3DGA) is shown to be a useful clinical tool for the evaluation of gait abnormality due to movement disorders. However, ...

3D Kinematic Gait Analysis for Preclinical Studies in Rodents

The utility of three-dimensional (3D) kinematic motion analysis systems is limited in rodents. Part of the reason for this inadequacy is the use of complex algorithms and mathematical modeling that accompany 3D data collection and analysis procedures. This work provides a simple, user-friendly, step-by-step detailed methodology for 3D kinematic gait analysis during treadmill locomotion in healthy and neurotraumatic rats using a six-camera motion capture system. Also provided are details on 1) calibration of the system in an experimental set-up customized for quadrupedal locomotion, 2) data collection for treadmill locomotion in adult rats using markers positioned on all four limbs, 3) options available for video tracking and processing, and 4) basic 3D kinematic data generation and visualization and quantification of data using the built-in data collection software. Finally, it is suggested that the utility of this motion capture system be expanded to studying a variety of motor behaviors before and after neurotrauma.

Presented here is a protocol to collect and analyze three-dimensional kinematics of quadrupedal locomotion in rodents for preclinical studies.

The utility of three-dimensional (3D) kinematic motion analysis systems is limited in rodents. Part of the reason for this inadequacy is the use of ...

Video Movement Analysis Using Smartphones (ViMAS): A Pilot Study

The use of smartphones in clinical practice is steadily increasing with the availability of low cost/freely available &#34;apps&#34; that could be used to assess human gait. The primary aim of this manuscript is to test the concurrent validity of kinematic measures recorded by a smartphone application in comparison to a 3D motion capture system in the sagittal plane. The secondary aim was to develop a protocol for clinicians on the set up of the smartphone camera for video movement analysis.
The sagittal plane knee angle was measured during heel strike and toe off events using the smart phone app and a 3D motion-capture system in 32 healthy subjects. Three trials were performed at near (2-m) and far (4-m) smartphone camera distances. The order of the distances was randomized. Regression analysis was performed to estimate the height of the camera based on either the subject&#39;s height or leg length.
Absolute measurement errors were least during toe off (3.12 &#177; 5.44 degrees) compared to heel strike (5.81 &#177; 5.26 degrees). There were significant (p &#60; 0.05) but moderate agreements between the application and 3D motion capture measures of knee angles. There were also no significant (p &#62; 0.05) differences between the absolute measurement errors between the two camera positions. The measurement errors averaged between 3 - 5 degrees during toe off and heel strike events of the gait cycle.
The use of smartphone apps can be a useful tool in the clinic for performing gait or human movement analysis. Further studies are needed to establish the accuracy in measuring movements of the upper extremity and trunk.

Video Movement Analysis Using Smartphones ViMAS: A Pilot Study

This manuscript describes the method to test the concurrent validity of kinematic measures recorded by the smartphone application in comparison to a 3D motion capture system in the sagittal plane. This protocol will enable clinicians to set up smartphones for video capture of human movement.

The use of smartphones in clinical practice is steadily increasing with the availability of low cost/freely available &#34;apps&#34; that could be used to ...

The Lower Body Positive Pressure Treadmill for Knee Osteoarthritis Rehabilitation

Here, based on a clinician&rsquo;s point-of-view, we propose a two-model lower body positive pressure (LBPP) protocol (walking and squatting models) in addition to a clinical, functional assessment methodology, including details for further encouragement of the development of non-drug surgical intervention strategies in knee osteoarthritis patients. However, we only present the effect of LBPP training in improvement of pain and knee function in one patient through three-dimensional gait analysis. The exact, long-term effects of this approach should be explored in future studies.

Here, based on a clinician&#8217;s point-of-view, we propose a two-model lower body positive pressure (LBPP) protocol (walking and squatting models) in addition to a clinical, functional assessment methodology, including details for further encouragement of the development of non-drug surgical intervention strategies in knee osteoarthritis patients. However, we only present the effect of LBPP training in improvement of pain and knee function in one patient through three-dimensional gait analysis. The exact, long-term effects of this approach should be explored in future studies.

Here, based on a clinician&rsquo;s point-of-view, we propose a two-model lower body positive pressure (LBPP) protocol (walking and squatting models) in ...

Motor Dual-Tasks for Gait Analysis and Evaluation in Post-Stroke Patients

Eighteen stroke patients were recruited for this study involving the evaluation of cognition and walking ability and multitask gait analysis. Multitask gait analysis consisted of a single walking task (Task 0), a simple motor dual-task (water-holding, Task 1), and a complex motor dual-task (crossing obstacles, Task 2). The task of crossing obstacles was considered to be equivalent to the combination of a simple walking task and a complex motor task as it involved more nervous system, skeletal movement, and cognitive resources. To eliminate heterogeneity in the results of the gait analysis of the stroke patients, the dual-task gait cost values were calculated for various kinematic parameters. The major differences were observed in the proximal joint angles, especially in the angles of the trunk, pelvis, and hip joints, which were significantly larger in the dual motor tasks than in the single walking task. This research protocol aims to provide a basis for the clinical diagnosis of gait function and an in-depth study of motor control in stroke patients with motor control deficits through the analyses of dual-motor walking tasks.

This paper presents a protocol specifically for dual motor task gait analysis in stroke patients with motor control deficits.

Eighteen stroke patients were recruited for this study involving the evaluation of cognition and walking ability and multitask gait analysis. Multitask ...

Neuroscience

Comprehensive Understanding of Inactivity-Induced Gait Alteration in Rodents

It is well known that disuse affects neural systems and that joint motions become altered; however, which outcomes properly exhibit these characteristics is still unclear. The present study describes a motion analysis approach that utilizes three-dimensional (3D) reconstruction from video captures. Using this technology, disuse-evoked alterations of walking performances were observed in rodents exposed to a simulated microgravity environment by unloading their hindlimb by their tail. After 2 weeks of unloading, the rats walked on a treadmill, and their gait motions were captured with four charge-coupled device (CCD) cameras. 3D motion profiles were reconstructed and compared to those of control subjects using the image processing software. The reconstructed outcome measures successfully portrayed distinct aspects of distorted gait motion: hyperextension of the knee and ankle joints and higher position of the hip joints during the stance phase. Motion analysis is useful for several reasons. First, it enables quantitative behavioral evaluations instead of subjective observations (e.g., pass/fail in certain tasks). Second, multiple parameters can be extracted to fit specific needs once the fundamental datasets are obtained. Despite hurdles for broader application, the disadvantages of this method, including labor intensity and cost, may be alleviated by determining comprehensive measurements and experimental procedures.

The present protocol describes three-dimensional motion tracking/evaluation to depict gait motion alteration of rats after exposure to a simulated disuse environment.

It is well known that disuse affects neural systems and that joint motions become altered; however, which outcomes properly exhibit these characteristics ...

Biomechanical Analysis of Adjacent Segments after Spinal Fusion Surgery Using a Geometrically Parametric Patient-Specific Finite Element Model

This study aimed to perform a mechanical analysis of adjacent segments after spinal fusion surgery using a geometrically parametric patient-specific finite element model to elucidate the mechanism of adjacent segment degeneration (ASD), thereby providing theoretical evidence for early disease prevention. Fourteen parameters based on patient-specific spinal geometry were extracted from a patient's preoperative computed tomography (CT) scan, and the relative positions of each spinal segment were determined using the image match method. A preoperative patient-specific model of the spine was established through the above method. The postoperative model after L4-L5 posterior lumbar interbody fusion (PLIF) surgery was constructed using the same method except that the lamina and intervertebral disc were removed, and a cage, 4 pedicle screws, and 2 connecting rods were inserted. Range of motion (ROM) and stress changes were determined by comparing the values of each anatomical structure between the preoperative and postoperative models. The overall ROM of the lumbar spine decreased after fusion, while the ROM, stress in the facet joints, and stress in the intervertebral disc of adjacent segments all increased. An analysis of the stress distribution in the annulus fibrosus, nucleus pulposus, and facet joints also showed that not only was the maximum stress in these tissues elevated, but the areas of moderate-to-high stress were also expanded. During torsion, the stress in the facet joints and annulus fibrosus of the proximal adjacent segment (L3-L4) increased to a larger extent than that in the distal adjacent segment (L5-S1). While fusion surgery causes an overall restriction of motion in the lumbar spine, it also causes more load sharing by the adjacent segments to compensate for the fused segment, thus increasing the risk of ASD. The proximal adjacent segment is more prone to degeneration than the distal adjacent segment after spinal fusion due to the significant increase in stress.

Here, we used a patient-specific finite element model to analyze the mechanical changes in adjacent segments after spinal fusion surgery. The results showed that fusion surgery reduced the overall motion of the lumbar spine but increased the load on and stress in adjacent segments, especially the proximal segment.

This study aimed to perform a mechanical analysis of adjacent segments after spinal fusion surgery using a geometrically parametric patient-specific ...

Oblique Lumbar Interbody Fusion at L5-S1 Segment Through an Approach Between the Psoas Muscle and the Great Vessels

Over the years, the oblique lateral interbody fusion (OLIF) technique has gained significant recognition for treating various spinal conditions in lumbar segments L2-L5. However, the adoption of OLIF for the L5-S1 segment has not been widely embraced by the spinal surgery community, given that significant concerns remain regarding the applicability of OLIF for lumbosacral fusion. In this study, a cohort of 20 patients underwent interbody fusion at the L5-S1 level using the OLIF technique through a single retroperitoneal oblique approach positioned between the Psoas muscle and the great vessels. The procedure involved discectomy and endplate preparation accomplished through a surgical window created on the anterolateral side of the L5-S1 disc. For secure interbody fusion cage placement, a supplementary cage insertion approach was employed. All patients were followed up for a minimum of 12 months. The mean preoperative visual analog scale (VAS) score for lower back pain was 6.3 &#177; 1.5 and experienced a significant reduction to 1.2 &#177; 0.8 at 12 months. The VAS score for lower limb pain significantly decreased from 5.6 &#177; 1.4 preoperatively to 0.8 &#177; 0.3 at 12 months after the surgery. Furthermore, the preoperative Oswestry disability index (ODI) improved from 82.4% &#177; 16.2% to 8.1% &#177; 2.0% at 12 months. Radiographic evaluations after surgery confirmed improved lumbosacral junction reconstruction for all patients. At the final follow-up, successful bony fusion was observed in all cases. Based on these findings, the OLIF technique for L5-S1 fusion represents an attainable approach for lumbosacral reconstruction. The procedure&#39;s success hinges on a comprehensive preoperative plan and precise intraoperative techniques.

The protocol presents an OLIF L5-S1 technique that offers a more feasible approach for lumbosacral fusion sharing a common surgical plane with OLIF L2-5. This facilitates reproducible multi-level interbody fusions extending from L2 to S1 through a retroperitoneal oblique corridor between the Psoas muscle and the great vessels.

Over the years, the oblique lateral interbody fusion (OLIF) technique has gained significant recognition for treating various spinal conditions in lumbar ...

Innovative Video-Based Tool for Precision Assessment and Rehabilitation of LBP

Biomechanical Changes Related to Low Back Pain: An Innovative Tool for Movement Pattern Assessment and Treatment Evaluation in Rehabilitation

Low back pain (LBP) is a highly prevalent disorder frequently related to biomechanical alterations. Movement pattern assessments have a role in the rehabilitation management of patients with LBP; however, a precise assessment is challenging in routine clinical settings. Thus, this study aims to assess the biomechanical alterations related to LBP through the development and application of an innovative assessment tool named CameraLab. Patients with LBP were assessed through a video analysis system. The movement pattern assessment tool includes a touchscreen interface and four high-velocity cameras, enabling real-time data acquisition during movement assessments. The cameras capture dynamic movements, facilitating a thorough examination of motor function. A video analysis software application is employed for precise angle assessments and joint tracking. Three patients with LBP were assessed, demonstrating positive results in pain intensity, functional independence, and overall well-being. The integration of advanced technology highlighted the movement pattern alterations and contributed to tailored rehabilitation strategies. The study offers a paradigm shift toward precision rehabilitation. This innovative approach provides valuable insights into the biomechanical changes related to LBP, fostering a deeper understanding for clinicians and paving the way for effective personalized interventions in the management of LBP.

This study shows the role of an innovative tool for assessing and treating biomechanical alterations in low back pain (LBP) patients. Three LBP patients demonstrated improved pain intensity and functional independence post-assessment. The technology aids in tailored rehabilitation strategies, offering insights into LBP biomechanics for personalized interventions.

Low back pain (LBP) is a highly prevalent disorder frequently related to biomechanical alterations. Movement pattern assessments have a role in the ...

Evaluation of Patients' Posture and Gait Profile After Lumbar Fusion Surgery by Video Rasterstereography and Treadmill Gait Analysis

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