TY - JOUR
T1 - Primary drivers of adult cervical deformity
T2 - Prevalence, variations in presentation, and effect of surgical treatment strategies on early postoperative alignment
AU - International Spine Study Group
AU - Passias, Peter G.
AU - Jalai, Cyrus M.
AU - Lafage, Virginie
AU - Lafage, Renaud
AU - Protopsaltis, Themistocles
AU - Ramchandran, Subaraman
AU - Horn, Samantha R.
AU - Poorman, Gregory W.
AU - Gupta, Munish
AU - Hart, Robert A.
AU - Deviren, Vedat
AU - Soroceanu, Alexandra
AU - Smith, Justin S.
AU - Schwab, Frank
AU - Shaffrey, Christopher I.
AU - Ames, Christopher P.
N1 - Funding Information:
This study was supported by a grant received from DePuy Spine to the International Spine Study Group Foundation. Funds were used to pay for data collection support. This work, as part of the International Spine Study Group (ISSG), is funded through research grants from DePuy Spine and individual donations. Dr Passias reports consultancy from Medicrea and Spinewave and Educational Course from Zimmer Biomet. Dr Hart reports board membership for ISSG, ISSLS, CSRS, consultancy for DePuy, Globus, and Medtronic, royalties from Seaspine and DePuy Synthes, stock from Spine Connect, and speaking/teaching arrangements for DePuy Synthes. Dr Deviren reports Consultancy from NuVasive, Guidepoint, and Stryker. Dr Smith reports consultancy from Biomet, Medtronic, and Stryker; Fellowship Support from Neurosurgery Research and Education Foundation (NREF) and AOSpine. Dr Lafage reports Speaking/Teaching arrangements/consultancy from NuVasive, Medicrea, DePuy Spine, and Nemaris INC, she is a Shareholder, Board of Directors for Nemaris INC. Dr Protopsaltis reports consultancy from Medicrea International. Dr Schwab reports Grant from SRS and AO; consultancy/speaking/teaching arrangements for Zimmer-Biomet, K2M, MSD, Medicrea, and NuVasive; Board of Directors at Nemaris INC. Dr Shaffrey reports consultancy for Biomet, Globus, Medtronic, NuVasive, and Stryker; Royalties from Medtronic and Biomet; Fellowship Support from NREF, AO, University of Virginia. Dr Ames reports consultancy for DePuy, Medtronic, and Stryker and royalties from Biomet and Stryker. The following authors report no additional conflicts of interest or financial disclosures: Mr Jalai, Mr Lafage, Dr Diebo, Ms Horn, Mr Poorman, Dr Ramchandran, Dr Soroceanu, Dr Gupta.
Publisher Copyright:
© 2017 by the Congress of Neurological Surgeons
PY - 2018/10/1
Y1 - 2018/10/1
N2 - BACKGROUND: Primary drivers (PDs) of adult cervical deformity (ACD) have not been described in relation to pre- and early postoperative alignment or degree of correction. OBJECTIVE: To define the PDs of ACD to understand the impact of driver region on global postoperative compensatory mechanisms. METHODS: Primary cervical deformity driver/vertebral apex level were determined: CS = cervical; CTJ = cervicothoracic junction; TH = thoracic; SP = spinopelvic. Patients were evaluated if surgery included PD apex, based on the lowest instrumented vertebra (LIV): CS: LIV ≤ C7, CTJ: LIV ≤ T3, TH: LIV ≤ T12. Cervical and thoracolumbar alignment was measured preoperatively and 3 mo (3M) postoperatively. PD groups were compared with analysis of variance/Pearson χ2, paired t-tests. RESULTS: Eighty-four ACD patients met inclusion criteria. Thoracic drivers (n = 26) showed greatest preoperative cervical and global malalignment against other PD: higher thoracic kyphosis, pelvic incidence-lumbar lordosis (PI-LL), T1 slope C2-T3 sagittal vertical axis (SVA), and C0-2 angle (P < .05). Differences in baseline-3M alignment changes were observed between surgical PD groups, in PI-LL, LL, T1 slope minus cervical lordosis (TS-CL), cervical SVA, C2-T3 SVA (P < .05). Main changes were between TH and CS driver groups: TH patients had greater PI-LL (4.47◦ vs −0.87◦, P = .049), TS-CL (−19.12◦ vs −4.30, P = .050), C2-C7 SVA (−18.12 vs −4.30 mm, P = .007), and C2-T3 SVA (−24.76 vs 8.50 mm, P = .002) baseline-3M correction. CTJ drivers trended toward greater LL correction compared to CS drivers (−6.00◦ vs 0.88◦, P = .050). Patients operated at CS driver level had a difference in the prevalence of 3M TS-CL modifier grades (0 = 35.7%, 1 = 0.0%, 2 = 13.3%, P = .030). There was a significant difference in 3M chin-brow vertical angle modifier grade distribution in TH drivers (0 = 0.0%, 1 = 35.9%, 2 = 14.3%, P = .049). CONCLUSION: Characterizing ACD patients by PD type reveals differences in pre- and postoperative alignment. Evaluating surgical alignment outcomes based on PD inclusion is important in understanding alignment goals for ACD correction.
AB - BACKGROUND: Primary drivers (PDs) of adult cervical deformity (ACD) have not been described in relation to pre- and early postoperative alignment or degree of correction. OBJECTIVE: To define the PDs of ACD to understand the impact of driver region on global postoperative compensatory mechanisms. METHODS: Primary cervical deformity driver/vertebral apex level were determined: CS = cervical; CTJ = cervicothoracic junction; TH = thoracic; SP = spinopelvic. Patients were evaluated if surgery included PD apex, based on the lowest instrumented vertebra (LIV): CS: LIV ≤ C7, CTJ: LIV ≤ T3, TH: LIV ≤ T12. Cervical and thoracolumbar alignment was measured preoperatively and 3 mo (3M) postoperatively. PD groups were compared with analysis of variance/Pearson χ2, paired t-tests. RESULTS: Eighty-four ACD patients met inclusion criteria. Thoracic drivers (n = 26) showed greatest preoperative cervical and global malalignment against other PD: higher thoracic kyphosis, pelvic incidence-lumbar lordosis (PI-LL), T1 slope C2-T3 sagittal vertical axis (SVA), and C0-2 angle (P < .05). Differences in baseline-3M alignment changes were observed between surgical PD groups, in PI-LL, LL, T1 slope minus cervical lordosis (TS-CL), cervical SVA, C2-T3 SVA (P < .05). Main changes were between TH and CS driver groups: TH patients had greater PI-LL (4.47◦ vs −0.87◦, P = .049), TS-CL (−19.12◦ vs −4.30, P = .050), C2-C7 SVA (−18.12 vs −4.30 mm, P = .007), and C2-T3 SVA (−24.76 vs 8.50 mm, P = .002) baseline-3M correction. CTJ drivers trended toward greater LL correction compared to CS drivers (−6.00◦ vs 0.88◦, P = .050). Patients operated at CS driver level had a difference in the prevalence of 3M TS-CL modifier grades (0 = 35.7%, 1 = 0.0%, 2 = 13.3%, P = .030). There was a significant difference in 3M chin-brow vertical angle modifier grade distribution in TH drivers (0 = 0.0%, 1 = 35.9%, 2 = 14.3%, P = .049). CONCLUSION: Characterizing ACD patients by PD type reveals differences in pre- and postoperative alignment. Evaluating surgical alignment outcomes based on PD inclusion is important in understanding alignment goals for ACD correction.
KW - Adult cervical deformity
KW - Cervical spine
KW - Cervicothoracic junction
KW - Compensatory mechanisms
KW - Postoperative alignment
KW - Primary driver
KW - Surgical correction
UR - http://www.scopus.com/inward/record.url?scp=85044115839&partnerID=8YFLogxK
U2 - 10.1093/neuros/nyx438
DO - 10.1093/neuros/nyx438
M3 - Article
C2 - 28950349
AN - SCOPUS:85044115839
SN - 0148-396X
VL - 83
SP - 651
EP - 659
JO - Clinical Neurosurgery
JF - Clinical Neurosurgery
IS - 4
ER -