OBJECTIVEThe Ames-International Spine Study Group (ISSG) classification has recently been proposed as a tool for adult cervical deformity evaluation. This classification includes three radiographic cervical sagittal modifiers that have not been evaluated in asymptomatic adults. The aim of this study was to determine whether the sagittal radiographic modifiers described in the Ames-ISSG cervical classification are encountered in asymptomatic adults without alteration of health-related quality of life (HRQOL).METHODSThe authors conducted a cross-sectional study of subjects with an age ≥ 18 years and no cervical or back-related complaints or history of orthopedic surgery. All subjects underwent full-body biplanar radiographs with the measurement of cervical, segmental, and global alignment and completed the SF-36 HRQOL questionnaire. Subjects were classified according to the sagittal radiographic modifiers (chin-brow vertical angle [CBVA], mismatch between T1 slope and cervical lordosis [TS-CL], and C2-7 sagittal vertical axis [cSVA]) of the Ames-ISSG classification for cervical deformity, which also includes a qualitative descriptor of cervical deformity, the modified Japanese Orthopaedic Association (mJOA) myelopathy score, and the Scoliosis Research Society (SRS)-Schwab classification for spinal deformity assessment. Characteristics of the subjects classified by the different modifier grades were compared.RESULTSOne hundred forty-one asymptomatic subjects (ages 18-59 years, 71 females) were enrolled in the study. Twenty-seven (19.1%) and 61 (43.3%) subjects were classified as grade 1 in terms of the TS-CL and CBVA modifiers, respectively. Ninety-eight (69.5%) and 4 (2.8%) were grade 2 for these same respective modifiers. One hundred thirty-six (96.5%) subjects had at least one modifier at grade 1 or 2. There was a significant relationship between patient age and grades of TS-CL (p < 0.001, Cramer's V [CV] = 0.32) and CBVA (p = 0.04, CV = 0.22) modifiers. The HRQOL, global alignment, and segmental alignment parameters were similar among the subjects with different modifier grades (p > 0.05).CONCLUSIONSThe CBVA and TS-CL radiographic modifiers of the Ames-ISSG classification do not seem to be specific to subjects with cervical deformities and can occur in asymptomatic subjects without alteration in HRQOL.
Keywords: ASD = adult spinal deformity; Ames-ISSG classification; BMI = body mass index; CBVA = chin-brow vertical angle; CL = cervical lordosis; HRQOL = health-related quality of life; ISSG = International Spine Study Group; PI-LL = pelvic incidence–lumbar lordosis; SRS = Scoliosis Research Society; SVA = sagittal vertical axis; TS-CL = mismatch between T1 slope and cervical lordosis; asymptomatic adults; cSVA = C2–7 SVA; cervical alignment; deformity; health-related quality of life; mJOA = modified Japanese Orthopaedic Association; sagittal alignment.