Hiroko Matsumoto1, Nicholas D Colacchio2, Frank J Schwab3, Virginie Lafage3, David P Roye4, Michael G Vitale4. 1. Department of Orthopaedic Surgery, Columbia University Medical Center, 3959 Broadway, 800 North, New York, NY 10032, USA; Department of Epidemiology, Mailmen School of Public Health at Columbia University, 722 West 168th Street, New York, NY 10032, USA. Electronic address: hm2174@columbia.edu. 2. Department of Orthopaedics, Tufts University Medical Center, Boston, MA, USA. 3. Department of Orthopaedic Surgery, New York University Medical School, 301 East 17th Street, New York, NY 10003, USA. 4. Department of Orthopaedic Surgery, Columbia University Medical Center, 3959 Broadway, 800 North, New York, NY 10032, USA.
Abstract
STUDY DESIGN: Retrospective review of prospective multicenter adolescent idiopathic scoliosis (AIS) database. OBJECTIVE: To investigate the relationship between iatrogenic loss of thoracic kyphosis (TK) after selective thoracic posterior spinal instrumentation and fusion (PSIF) for AIS with straightening of lumbar lordosis (LL). SUMMARY OF BACKGROUND DATA: Segmental PSIF has become the standard of care for surgical treatment of severe AIS. Studies show that adults with flattening of TK and LL can develop pain and dysfunction associated with flatback syndrome. Analysis of post-fusion sagittal alignment is lacking in the AIS population. METHODS: Query of prospective multicenter database for AIS patients with Lenke 1, 2, or 3 curves who underwent selective thoracic PSIF (lowest instrumented vertebra equal or cephalad to L1) identified 123 patients with a minimum of 2 years' follow-up. Thoracic kyphosis (T5-T12), LL (T12-S1), and global sagittal alignment were measured preoperatively and at 2 years postoperatively. Health-related quality of life measures were examined. RESULTS: A total of 31% of patients had loss of TK and 42% lost LL. Patients with decreased TK had significantly higher rates of decreased LL (68%) than patients without decreased TK (31%). Multivariate regression confirmed that TK had significant predictive effect on LL (p < .001). Specifically, change in TK of 2° was associated with roughly 3° change in LL. There were no significant associations between changes in TK or LL and health-related quality of life. CONCLUSIONS: Loss of TK occurs commonly in selective fusion for AIS. This loss of kyphosis is strongly associated with reciprocal loss of LL. Spinal fusion can have unintended effects on sagittal alignment; these effects may have consequences that remain to be fully elucidated.
STUDY DESIGN: Retrospective review of prospective multicenter adolescent idiopathic scoliosis (AIS) database. OBJECTIVE: To investigate the relationship between iatrogenic loss of thoracic kyphosis (TK) after selective thoracic posterior spinal instrumentation and fusion (PSIF) for AIS with straightening of lumbar lordosis (LL). SUMMARY OF BACKGROUND DATA: Segmental PSIF has become the standard of care for surgical treatment of severe AIS. Studies show that adults with flattening of TK and LL can develop pain and dysfunction associated with flatback syndrome. Analysis of post-fusion sagittal alignment is lacking in the AIS population. METHODS: Query of prospective multicenter database for AIS patients with Lenke 1, 2, or 3 curves who underwent selective thoracic PSIF (lowest instrumented vertebra equal or cephalad to L1) identified 123 patients with a minimum of 2 years' follow-up. Thoracic kyphosis (T5-T12), LL (T12-S1), and global sagittal alignment were measured preoperatively and at 2 years postoperatively. Health-related quality of life measures were examined. RESULTS: A total of 31% of patients had loss of TK and 42% lost LL. Patients with decreased TK had significantly higher rates of decreased LL (68%) than patients without decreased TK (31%). Multivariate regression confirmed that TK had significant predictive effect on LL (p < .001). Specifically, change in TK of 2° was associated with roughly 3° change in LL. There were no significant associations between changes in TK or LL and health-related quality of life. CONCLUSIONS: Loss of TK occurs commonly in selective fusion for AIS. This loss of kyphosis is strongly associated with reciprocal loss of LL. Spinal fusion can have unintended effects on sagittal alignment; these effects may have consequences that remain to be fully elucidated.
Authors: Bryan Ang; Renaud Lafage; Jonathan Charles Elysée; Tejbir S Pannu; Mathieu Bannwarth; Brandon B Carlson; Frank J Schwab; Han Jo Kim; Virginie Lafage Journal: Global Spine J Date: 2020-04-01