Renaud Lafage1, Shay Bess2, Steve Glassman3, Christopher Ames4, Douglas Burton5, Robert Hart6, Han J Kim1, Eric Klineberg7, Jensen Henry2, Breton Line8, Justin Scheer9, Themistocles Protopsaltis2, Frank Schwab1, Virginie Lafage1. 1. Spine Service, Hospital for Special Surgery, New York, NY. 2. Spine Division, Department of Orthopedics, NYU Langone Medical Center, New York, NY. 3. Department of Orthopedic Surgery, University of Louisville Medical Center, Louisville, KY. 4. Department of Neurosurgery, San Francisco Medical Center, University of California, San Francisco, CA. 5. Department of Orthopedic Surgery, University of Kansas Medical Center, Kansas City, KS. 6. Department of Orthopedic Surgery, Oregon Health Sciences University, Portland, OR. 7. Department of Orthopedic Surgery, University of California, Davis, Sacramento, CA. 8. Rocky Mountain Hospital for Children Denver, Denver, CO. 9. Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL.
Abstract
STUDY DESIGN: Retrospective review of a prospective multicenter database. OBJECTIVE: To develop a method to analyze sagittal alignment, free of the influence of proximal junctional kyphosis (PJK), and then compare PJK to non-PJK patients using this method. SUMMARY OF BACKGROUND DATA: PJK after adult spinal deformity (ASD) surgery remains problematic as it alters sagittal alignment. The present study proposes a novel virtual modeling technique that attempts to eliminate the confounding effects of PJK on postoperative spinal alignment. METHODS: A virtual spinal modeling technique was developed on a retrospective ASD cohort of patients with multilevel spinal fusions to the pelvis with at least 2-year postoperative follow-up. The virtual postoperative alignment (VIRTUAL) was created from the postoperative alignment of the instrumented segments and the preoperative alignment of the unfused segments. VIRTUAL was validated by comparisons to actual 2-year postoperative alignment (REAL) in non-PJK patients. Patients were then divided into two groups: PJK and non-PJK based on the presence/absence of PJK at 2 years postoperatively. PJK and non-PJK patients were compared using VIRTUAL and REAL. RESULTS: A total of 458 patients (78F, mean 57.9 yr) were analyzed. The validation of VIRTUAL versus REAL demonstrated correlation coefficients greater than 0.7 for all measures except sagittal vertical axis (SVA; r = 0.604). At 2 years, REAL alignment in PJK patients demonstrated a smaller pelvic incidence minus lumbar lordosis and a larger thoracic kyphosis than non-PJK patients, but similar SVA, T1 pelvic angle, and pelvic tilt. An analysis of VIRTUAL demonstrated that patients with PJK had a smaller pelvic incidence minus lumbar lordosis, pelvic tilt, SVA, and T1 pelvic angle than non-PJK patients (P < 0.05). CONCLUSION: This technique demonstrated strong correlations with actual postoperative alignment. Comparisons between REAL and VIRTUAL alignments revealed that postoperative PJK may develop partially as a compensatory mechanism to the overcorrection of sagittal deformities. Future research will evaluate the appropriate thresholds for deformity correction according to age and ASD severity. LEVEL OF EVIDENCE: 3.
STUDY DESIGN: Retrospective review of a prospective multicenter database. OBJECTIVE: To develop a method to analyze sagittal alignment, free of the influence of proximal junctional kyphosis (PJK), and then compare PJK to non-PJK patients using this method. SUMMARY OF BACKGROUND DATA: PJK after adult spinal deformity (ASD) surgery remains problematic as it alters sagittal alignment. The present study proposes a novel virtual modeling technique that attempts to eliminate the confounding effects of PJK on postoperative spinal alignment. METHODS: A virtual spinal modeling technique was developed on a retrospective ASD cohort of patients with multilevel spinal fusions to the pelvis with at least 2-year postoperative follow-up. The virtual postoperative alignment (VIRTUAL) was created from the postoperative alignment of the instrumented segments and the preoperative alignment of the unfused segments. VIRTUAL was validated by comparisons to actual 2-year postoperative alignment (REAL) in non-PJK patients. Patients were then divided into two groups: PJK and non-PJK based on the presence/absence of PJK at 2 years postoperatively. PJK and non-PJK patients were compared using VIRTUAL and REAL. RESULTS: A total of 458 patients (78F, mean 57.9 yr) were analyzed. The validation of VIRTUAL versus REAL demonstrated correlation coefficients greater than 0.7 for all measures except sagittal vertical axis (SVA; r = 0.604). At 2 years, REAL alignment in PJK patients demonstrated a smaller pelvic incidence minus lumbar lordosis and a larger thoracic kyphosis than non-PJK patients, but similar SVA, T1 pelvic angle, and pelvic tilt. An analysis of VIRTUAL demonstrated that patients with PJK had a smaller pelvic incidence minus lumbar lordosis, pelvic tilt, SVA, and T1 pelvic angle than non-PJK patients (P < 0.05). CONCLUSION: This technique demonstrated strong correlations with actual postoperative alignment. Comparisons between REAL and VIRTUAL alignments revealed that postoperative PJK may develop partially as a compensatory mechanism to the overcorrection of sagittal deformities. Future research will evaluate the appropriate thresholds for deformity correction according to age and ASD severity. LEVEL OF EVIDENCE: 3.
Authors: Justin S Smith; Christopher I Shaffrey; Michael P Kelly; Elizabeth L Yanik; Jon D Lurie; Christine R Baldus; Charles Edwards; Steven D Glassman; Lawrence G Lenke; Oheneba Boachie-Adjei; Jacob M Buchowski; Leah Y Carreon; Charles H Crawford; Thomas J Errico; Stephen J Lewis; Tyler Koski; Stefan Parent; Han Jo Kim; Christopher P Ames; Shay Bess; Frank J Schwab; Keith H Bridwell Journal: Spine (Phila Pa 1976) Date: 2019-09-01 Impact factor: 3.241
Authors: Han Jo Kim; Philip J York; Jonathan C Elysee; Christopher Shaffrey; Douglas C Burton; Christopher P Ames; Gregory M Mundis; Richard Hostin; Shay Bess; Eric Klineberg; Justin S Smith; Peter Passias; Frank Schwab; Renaud Lafage Journal: Global Spine J Date: 2019-09-30
Authors: Rakesh Mishra; M D Krishna Narayanan; Giuseppe E Umana; Nicola Montemurro; Bipin Chaurasia; Harsh Deora Journal: Int J Environ Res Public Health Date: 2022-02-02 Impact factor: 3.390
Authors: Yoshihiro Katsuura; Renaud Lafage; Han Jo Kim; Justin S Smith; Breton Line; Christopher Shaffrey; Douglas C Burton; Christopher P Ames; Gregory M Mundis; Richard Hostin; Shay Bess; Eric O Klineberg; Peter G Passias; Virginie Lafage Journal: Global Spine J Date: 2021-01-29