Reliability of trunk shape measurements based on 3-D surface reconstructions.
This study aimed to estimate the reliability of 3-D trunk surface measurements for the characterization of external asymmetry associated with scoliosis. Repeated trunk surface acquisitions using the Inspeck system (Inspeck Inc., Montreal, Canada), with two different postures A (anatomical position) and B (''clavicle'' position), were obtained from patients attending a scoliosis clinic. For each acquisition, a 3-D model of the patient's trunk was built and a series of measurements was computed. For each measure and posture, intraclass correlation coefficients (ICC) were obtained using a bivariate analysis of variance, and the smallest detectable difference was calculated. For posture A, reliability was fair to excellent with ICC from 0.91 to 0.99 (0.85 to 0.99 for the lower bound of the 95% confidence interval). For posture B, the ICC was 0.85 to 0.98 (0.74 to 0.99 for the lower bound of the 95% confidence interval). The smallest statistically significant differences for the maximal back surface rotation was 2.5 and 1.5 degrees for the maximal trunk rotation. Apparent global asymmetry and axial trunk rotation indices were relatively robust to changes in arm posture, both in terms of mean values and within-subject variations, and also showed a good reliability. Computing measurements from cross-sectional analysis enabled a reduction in errors compared to the measurements based on markers' position. Although not yet sensitive enough to detect small changes for monitoring of curve natural progression, trunk surface analysis can help to document the external asymmetry associated with different types of spinal curves as well as the cosmetic improvement obtained after surgical interventions. The anatomical posture is slightly more reliable as it allows a better coverage of the trunk surface by the digitizing system.
Pazos
Valérie
V
Computer Engineering, Ecole Polytechnique de Montreal, CP 6079, Succ. Centre-Ville, Montreal, QC, Canada H3C 1A7. valerie.pazos@polymtl.ca
Cheriet
Farida
F
Danserau
Jean
J
Ronsky
Janet
J
Zernicke
Ronald F
RF
Labelle
Hubert
H
D000293:Adolescent; D000328:Adult; D002648:Child; D015331:Cohort Studies; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D011187:Posture / Q000502:physiology*; D015203:Reproducibility of Results; D018401:Sample Size; D012600:Scoliosis / Q000503:physiopathology / Q000601:surgery
Spine (Phila Pa 1976). 2001 Jun 1;26(11):1274-8; discussion 1279
11389397
Spine (Phila Pa 1976). 1994 Jul 15;19(14):1562-72
7939992
Am Fam Physician. 2001 Jul 1;64(1):111-6
11456428
Spine (Phila Pa 1976). 2002 Jul 15;27(14):1543-50; discussion 1551-2
12131715
Clin Biomech (Bristol, Avon). 2002 Oct;17(8):559-68
12243715
Med Instrum. 1981 Mar-Apr;15(2):129-32
6453268
Int Orthop. 1982;6(1):55-60
6980848
Med Biol Eng Comput. 1987 Sep;25(5):583-5
3446982
Spine (Phila Pa 1976). 1988 Feb;13(2):146-51
3406833
Spine (Phila Pa 1976). 1988 Apr;13(4):405-8
3406848
Spine (Phila Pa 1976). 1988 Oct;13(10):1104-5
3061022
J Biomech. 1988;21(6):497-509
3209594
Spine (Phila Pa 1976). 1989 Jan;14(1):73-8
2913672
Spine (Phila Pa 1976). 1993 Mar 1;18(3):326-31
8475431
Rheumatology (Oxford). 2000 Apr;39(4):382-8
10817770
Eur Spine J. 1995;4(2):88-94
7600156
Spine (Phila Pa 1976). 1995 Dec 1;20(23):2487-92
8610242
Spine (Phila Pa 1976). 1996 Jan 1;21(1):59-64
9122764
Spine (Phila Pa 1976). 1997 Jun 1;22(11):1223-7; discussion 1228
9201860
Spine (Phila Pa 1976). 2005 Feb 15;30(4):427-33
15706340
Med Biol Eng Comput. 2005 Jan;43(1):11-5
15742714
J Pediatr Orthop. 2000 Jul-Aug;20(4):512-6
10912610
Spine (Phila Pa 1976). 2001 Feb 15;26(4):E55-63
11224901
Eur Spine J. 2001 Apr;10(2):101-7
11345629
Comput Methods Biomech Biomed Engin. 2000;4(1):59-75
11264861