Validation of a new computer-assisted tool to measure spino-pelvic parameters.
BACKGROUND
Evaluation of sagittal alignment is essential in the operative treatment of spine pathology, particularly adult spinal deformity (ASD). However, software applications for detailed spino-pelvic analysis are usually complex and not applicable to routine clinical use.


OBJECTIVE
This study aimed to validate new clinician-friendly software (Surgimap) in the setting of ASD.


METHODS
Accuracy and inter- and intra-rater reliability of spine measurement software were tested. Five users (two experienced spine surgeons, three novice spine research fellows) independently performed each part of the study in two rounds with 1 week between measurements.


METHODS
Fifty ASD patients drawn from a prospective database were used as the study sample.


METHODS
Spinal, pelvic, and cervical measurement parameters (including pelvic tilt [PT], pelvic incidence [PI], lumbar-pelvic mismatch [PI-LL], lumbar lordosis [LL], thoracic kyphosis [TK], T1 spino-pelvic inclination [T1SPI], sagittal vertical axis [SVA], and cervical lordosis [CL]) were the outcome measures.


METHODS
For the accuracy evaluation, 30 ASD patient radiographs were pre-marked for anatomic landmarks. Each radiograph was measured twice with the new software (Surgimap); measurements were compared to those from previously validated software. For the reliability and reproducibility evaluation, users measured 50 unmarked ASD radiographs in two rounds. Intra-class correlation (ICC) and International Organization for Standardization (ISO) reproducibility values were calculated. Measurement time was recorded.


RESULTS
Surgimap demonstrated excellent accuracy as assessed by the mean absolute difference from validated measurements: PT: 0.12°, PI: 0.35°, LL: 0.58°, PI-LL: 0.46°, TK: 5.25°, T1SPI: 0.53°, and SVA: 2.04 mm. The inter- and intra-observer reliability analysis revealed good to excellent agreement for all parameters. The mean difference between rounds was <0.4° for PT, PI, LL, PI-LL, and T1SPI, and <0.3 mm for SVA. For PT, PI, LL, PI-LL, TK, T1SPI, and SVA, the intra-observer ICC values were all >0.93 and the inter-observer ICC values were all >0.87. Parameters based on point landmarks rather than end plate orientation had a better reliability (ICC≥0.95 vs. ICC≥0.84). The average time needed to perform a full spino-pelvic analysis with Surgimap was 75 seconds (+25).


CONCLUSIONS
Using this new software tool, a simple method for full spine analysis can be performed quickly, accurately, and reliably. The proposed list of parameters offers quantitative values of the spine and pelvis, setting the stage for proper preoperative planning. The new software tool provides an important bridge between clinical and research needs.
Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, 301 E 17th St, New York, NY 10003.
Renaud
R
Lafage
Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, 301 E 17th St, New York, NY 10003.
Emmanuelle
E
Ferrero
Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, 301 E 17th St, New York, NY 10003.
Jensen K
JK
Henry
Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, 301 E 17th St, New York, NY 10003.
Vincent
V
Challier
Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, 301 E 17th St, New York, NY 10003.
Bassel
B
Diebo
Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, 301 E 17th St, New York, NY 10003.
Barthelemy
B
Liabaud
Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, 301 E 17th St, New York, NY 10003. Electronic address: virginie.lafage@gmail.com.
Virginie
V
Lafage
Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, 301 E 17th St, New York, NY 10003.
Frank
F
Schwab
D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D010388:Pelvis / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012984:Software; D013121:Spinal Curvatures / Q000000981:diagnostic imaging*; D013131:Spine / Q000000981:diagnostic imaging*
Accuracy; Computerized measurement; Reliability; Reproducibility; Spinal deformity; Spino-pelvic alignment