Three dimensional evaluation of posture in standing with the PosturePrint: an intra- and inter-examiner reliability study

Abstract Background Few digitizers can measure the complexity of upright human postural displacements in six degrees of freedom of the head, rib cage, and pelvis. Methods In a University laboratory, three examiners performed delayed repeated postural measurements on forty subjects over two days. Three digital photographs (left lateral, AP, right lateral) of each of 40 volunteer participants were obtained, twice, by three examiners. Examiners placed 13 markers on the subjects before photography and chose 16 points on the photographic images. Using the PosturePrint® internet computer system, head, rib cage, and pelvic postures were calculated as rotations (Rx, Ry, Rz) in degrees and translations (Tx, Tz) in millimeters. For reliability, two different types (liberal = ICC3,1 & conservative = ICC2,1) of inter- and intra-examiner correlation coefficients (ICC) were calculated. Standard error of measurements (SEM) and mean absolute differences within and between observers' measurements were also determined. Results All of the "liberal" ICCs were in the excellent range (> 0.84). For the more "conservative" type ICCs, four Inter-examiner ICCs were in the interval (0.5–0.6), 10 ICCs were in the interval (0.61–0.74), and the remainder were greater than 0.75. SEMs were 2.7° or less for all rotations and 5.9 mm or less for all translations. Mean absolute differences within examiners and between examiners were 3.5° or less for all rotations and 8.4 mm or less for all translations. Conclusion For the PosturePrint® system, the combined inter-examiner and intra-examiner correlation coefficients were in the good (14/44) and excellent (30/44) ranges. SEMs and mean absolute differences within and between examiners' measurements were small. Thus, this posture digitizer is reliable for clinical use

Abnormal Static Sagittal Cervical Curvatures following Motor Vehicle Collisions: A Retrospective Case Series of 41 Patients before and after a Crash Exposure

Previous investigations have found a correlation between abnormal curvatures and a variety of patient complaints such as cervical pain and disability. However, no study has shown that loss of the cervical curve is a direct result of exposure to a motor vehicle collision (MVC). This investigation presents a retrospective consecutive case series of patients with both a pre-injury cervical lateral radiograph (CLR) and a post-injury CLR after exposure to an MVC. Computer analysis of digitized vertebral body corners on CLRs was performed to investigate the possible alterations in the geometric alignment of the sagittal cervical curve. Methods: Three spine clinic records were reviewed over a 2-year period, looking for patients where both an initial lateral cervical X-ray and an examination were performed prior to the patient being exposed to a MVC; afterwards, an additional exam and radiographic analysis were obtained. A total of 41 patients met the inclusion criteria. Examination records of pain intensity on numerical pain rating scores (NPRS) and neck disability index (NDI), if available, were analyzed. The CLRs were digitized and modeled in the sagittal plane using curve fitting and the least squares error approach. Radiographic variables included total cervical curve (ARA C2–C7), Chamberlain’s line to horizontal (skull flexion), horizontal translation of C2 relative to C7, segmental translations (retrolisthesis and anterolisthesis), and circular modelling radii. Results: There were 15 males and 26 females with an age range of 8–65 years. Most participants were drivers (28) involved in rear-end impacts (30). The pre-injury NPRS was 2.7 while the post injury was 5.0; p < 0.001. The NDI was available on 24/41 (58.5%) patients and increased after the MVC from 15.7% to 32.8%, p < 0.001. An altered cervical curvature was identified following exposure to MVC, characterized by an increase in the mean radius of curvature (265.5 vs. 555.5, p < 0.001) and an approximate 8° reduction of lordosis from C2–C7; p < 0.001. The mid-cervical spine (C3–C5) showed the greatest curve reduction with an averaged localized mild kyphosis at these levels. Four participants (10%) developed segmental translations that were just below the threshold of instability, segmental translations < 3.5 mm. Conclusions: The post-exposure MVC cervical curvature was characterized by an increase in radius of curvature, an approximate 8° reduction in C2–C7 lordosis, a mild kyphosis of the mid-cervical spine, and a slight increase in anterior translation of C2–C7 sagittal balance. The modelling result indicates that the post-MVC cervical sagittal alignment approximates a second-order buckling alignment, indicating a significant alteration in curve geometry. Future biomechanics experiments and clinical investigations are needed to confirm these findings

Intra-Examiner Reliability and Validity of Sagittal Cervical Spine Mensuration Methods Using Deep Convolutional Neural Networks

Background: The biomechanical analysis of spine and postural misalignments is important for surgical and non-surgical treatment of spinal pain. We investigated the examiner reliability of sagittal cervical alignment variables compared to the reliability and concurrent validity of computer vision algorithms used in the PostureRay® software 2024. Methods: A retrospective database of 254 lateral cervical radiographs of patients between the ages of 11 and 86 is studied. The radiographs include clearly visualized C1–C7 vertebrae that were evaluated by a human using the software. To evaluate examiner reliability and the concurrent validity of the trained CNN performance, two blinded trials of radiographic digitization were performed by an extensively trained expert user (US) clinician with a two-week interval between trials. Then, the same clinician used the trained CNN twice to reproduce the same measures within a 2-week interval on the same 254 radiographs. Measured variables included segmental angles as relative rotation angles (RRA) C1–C7, Cobb angles C2–C7, relative segmental translations (RT) C1–C7, anterior translation C2–C7, and absolute rotation angle (ARA) C2–C7. Data were remotely extracted from the examiner’s PostureRay® system for data collection and sorted based on gender and stratification of degenerative changes. Reliability was assessed via intra-class correlations (ICC), root mean squared error (RMSE), and R2 values. Results: In comparing repeated measures of the CNN network to itself, perfect reliability was found for the ICC (1.0), RMSE (0), and R2 (1). The reliability of the trained expert US was in the excellent range for all variables, where 12/18 variables had ICCs ≥ 0.9 and 6/18 variables were 0.84 ≤ ICCs ≤ 0.89. Similarly, for the expert US, all R2 values were in the excellent range (R2 ≥ 0.7), and all RMSEs were small, being 0.42 ≤ RMSEs ≤ 3.27. Construct validity between the expert US and the CNN network was found to be in the excellent range with 18/18 ICCs in the excellent range (ICCs ≥ 0.8), 16/18 R2 values in the strong to excellent range (R2 ≥ 0.7), and 2/18 in the good to moderate range (R2 RT C6/C7 = 0.57 and R2 Cobb C6/C7 = 0.64. The RMSEs for expert US vs. the CNN network were small, being 0.37 ≤ RMSEs ≤ 2.89. Conclusions: A comparison of repeated measures within the computer vision CNN network and expert human found exceptional reliability and excellent construct validity when comparing the computer vision to the human observer

Three dimensional evaluation of posture in standing with the PosturePrint: an intra- and inter-examiner reliability study-1

<p><b>Copyright information:</b></p><p>Taken from "Three dimensional evaluation of posture in standing with the PosturePrint: an intra- and inter-examiner reliability study"</p><p>http://www.chiroandosteo.com/content/15/1/15</p><p>Chiropractic & Osteopathy 2007;15():15-15.</p><p>Published online 24 Sep 2007</p><p>PMCID:PMC2077332.</p><p></p>rePrintcomputer program, and used the computer mouse to click-on/identify 16 more anatomical points. (Reprinted with permission from Biotonix, Montreal, Quebec, Canada

Three dimensional evaluation of posture in standing with the PosturePrint: an intra- and inter-examiner reliability study-4

<p><b>Copyright information:</b></p><p>Taken from "Three dimensional evaluation of posture in standing with the PosturePrint: an intra- and inter-examiner reliability study"</p><p>http://www.chiroandosteo.com/content/15/1/15</p><p>Chiropractic & Osteopathy 2007;15():15-15.</p><p>Published online 24 Sep 2007</p><p>PMCID:PMC2077332.</p><p></p>positive to the anterior, postures of the head, rib cage, and pelvis can be described as translations (Tx, Ty, Tz) along these axes. Vertical translations (Ty), which would require radiographic analysis of hypo- or hyper-lordosis, were not calculated in the present study

Three dimensional evaluation of posture in standing with the PosturePrint: an intra- and inter-examiner reliability study-3

<p><b>Copyright information:</b></p><p>Taken from "Three dimensional evaluation of posture in standing with the PosturePrint: an intra- and inter-examiner reliability study"</p><p>http://www.chiroandosteo.com/content/15/1/15</p><p>Chiropractic & Osteopathy 2007;15():15-15.</p><p>Published online 24 Sep 2007</p><p>PMCID:PMC2077332.</p><p></p>positive to the anterior, postures of the head, rib cage, and pelvis can be described as rotations (Rx, Ry, Rz) around these axes

Three dimensional evaluation of posture in standing with the PosturePrint: an intra- and inter-examiner reliability study-2

<p><b>Copyright information:</b></p><p>Taken from "Three dimensional evaluation of posture in standing with the PosturePrint: an intra- and inter-examiner reliability study"</p><p>http://www.chiroandosteo.com/content/15/1/15</p><p>Chiropractic & Osteopathy 2007;15():15-15.</p><p>Published online 24 Sep 2007</p><p>PMCID:PMC2077332.</p><p></p>tcomputer program, and used the computer mouse to click-on/identify 16 more anatomical points. The computer program calculated postural displacements using these markers. Illustrated here are the markers easily visualized in the lateral view. (Reprinted with permission from Biotonix, Montreal, Quebec, Canada

Three dimensional evaluation of posture in standing with the PosturePrint: an intra- and inter-examiner reliability study-0

<p><b>Copyright information:</b></p><p>Taken from "Three dimensional evaluation of posture in standing with the PosturePrint: an intra- and inter-examiner reliability study"</p><p>http://www.chiroandosteo.com/content/15/1/15</p><p>Chiropractic & Osteopathy 2007;15():15-15.</p><p>Published online 24 Sep 2007</p><p>PMCID:PMC2077332.</p><p></p>tudy in a university laboratory