Correlation of Upper Instrumented Vertebrae and Future Cervical Spine Surgery to Patient-reported Outcomes in Adolescent Idiopathic Scoliosis Treated With Harrington Rod Instrumentation: A Minimum 40-year Follow-up.

STUDY

DESIGN

Long-term retrospective observational study.

OBJECTIVE

Assess the influence of upper instrumented vertebrae (UIV) and future cervical spine surgery on patient-reported outcomes in Adolescent Idiopathic Scoliosis (AIS) treated with Harrington rod fusion.

SUMMARY OF BACKGROUND DATA: Harrington rod has been largely replaced by pedicle screw fixation due to many considerations, including complications like pseudoarthrosis and implant failure. UIV and future spine surgery are known factors that affect patient-reported outcomes.

METHODS

We identified 318 AIS patients treated with Harrington rod instrumentation and fusion between 1961 and 1978. Patient questionnaires were completed, observing: NDI, SRS-7, PROMIS physical function (PF), PROMIS depression (D), and PROMIS pain interference (PI). Statistical analysis was used to compare outcome measures based on UIV and future cervical spine surgery.

RESULTS

In patients without cervical spine surgery, those with UIV of T5 and proximal had average NDI (P=0.14) of 10.2±11.2 and SRS-7 (P=0.73) of 22.9±3.4 compared with patients with UIV T6 and distal having NDI and SRS-7 of 14.6±11.6 and 22.8±2.6. Patients without cervical spine surgery with UIV of T5 and proximal had average PROMIS PF (P=0.17) of 45.5±2.8, PROMIS D (P=0.73) of 51.8±2.7, and PROMIS PI (P=0.43) of 53.9±1.9 compared with patients with UIV T6 and distal having PROMIS PF, D, and PI scores of 43.5±2.6, 49±3.2, and 55.6±1.9, respectively. Patients with cervical spine surgery had a mean NDI (P=0.13) of 23±1.4, SRS-7 (P=0.12) of 16, PROMIS PF (P=0.11) of 39.2±2.4, and PROMIS D (P=0.43) of 55.7±2.3 as compared with NDI of 11.9±11.5, SRS-7 of 22.8±3.1, PROMIS PF of 43.5±2.6, and PROMIS D of 49.0 ± 3.2 in patients without cervical spine surgery.

CONCLUSION

In long-term follow-up of AIS patients who underwent Harrington rod instrumentation, patient-reported outcomes were not associated with UIV or future cervical spine surgery; patients undergoing future cervical spine surgery did report greater pain interference.

LEVEL OF EVIDENCE: Level IV.