Our results in a cohort of patients with segmental instrumentation using hooks are similar to results in other studies of long-term HR-QOL measures in patients with AIS and Harrington rod instrumentation. Danielsson and Nachemson35 evaluated patients with surgically treated AIS with at least 20-year follow-up and reported that, in their surgical cohort with a mean age of 39.7 years, mean SF-36 PCS score was 50.9, and mean SF-36 MCS score was 50.2. In a recent study of patients with AIS and Harrington rod instrumentation, those of a mean age of 32.3 years had a mean score of 50.9 for both SF-36 PCS and SF-36 MCS.36
Regression analysis identified only smoking as a predictor of SRS-22R Total scores. This finding, that smokers have a lower health state, is expected even in the general population.37 Interestingly, bracing before surgery, Lenke type, surgery type, number of levels fused, lowest instrumented vertebra, incidence of perioperative complications, percentage curve correction, postoperative sagittal and coronal balance, and need for revision surgery did not influence HR-QOL measures in this cohort.
Our cohort’s incidence of occasional back pain was 76% (90/118 patients). Other reports have had similar findings. In 2012, Bas and colleagues38 studied self-reported pain in 126 consecutive patients with scoliosis and instrumented fusion. In their cohort, “most participants reported ‘no pain’ (38.5%) or ‘mild pain’ (30.8%) and 72.1% of participants reported a current work/school activity level of 100% normal.” Also in 2012, Rushton and Grevitt39 reported on a review and statistical analysis of the literature on HR-QOL in adolescents with untreated AIS and in unaffected adolescents. Their goal was to identify whether there were any differences in HR-QOL and, if so, whether they were clinically relevant. The authors concluded that pain and self-image tended to be statistically lower among cohorts with AIS but that only self-image was consistently different clinically between untreated patients with AIS and their unaffected peers.
Cosmetic complaints, though less common than functional concerns, affected a substantial percentage of our cohort. Waistline imbalance complaints were more common than rib prominence or scar-related complaints. The validity of patient-reported waistline imbalance is not known but may contribute to the SRS-22R outcomes in this cohort, particularly with regard to appearance scores. Respiratory symptoms, particularly those related to shortness of breath, were reported by 15% of patients. Respiratory symptoms may be in part secondary to underlying lung disease; smoking was reported by 21% of patients and asthma by 9%.
Few additional postoperative treatments were reported by patients. The most common treatment was regular use of NSAIDs (21%), followed by postoperative physical therapy (12%). Opiate medication use and spinal injections were rare—consistent with results reported by Danielsson and Nachemson35 in 2003.
Implant-related complaints, including painful instrumentation (13%) and implant prominence (9%), were some of the most common complaints in our study group. Although not all symptomatic instrumentation required surgical revision, 7 (50%) of the 14 additional spine surgeries were related to painful and/or prominent posterior instrumentation. Additional spine surgery was reported in 11.9% of our patients. Other indications for reoperation were disc herniation, crankshaft phenomenon, nonunion, and adjacent-level degeneration. Our rate of revision surgery is supported by the literature. In 2009, Luhmann and colleagues40 reported that 41 (3.9%) of 1057 primary spine fusions for idiopathic scoliosis required reoperation; the indications included infection (16/1057, 1.5%), pseudarthrosis (12, 1.1%), and painful/prominent implant (7, 0.7%). Richards and colleagues41 similarly reported on 1046 patients who underwent fusion for AIS. Of these patients, 135 underwent 172 repeat surgical interventions (12.9% reoperation rate), with 29 (21.5%) of the 135 undergoing 2 or more separate procedures. The most common reasons for reoperation were infection, symptomatic implant, and pseudarthrosis. The authors concluded that repeat surgeries were relatively common after the initial surgical procedures. Having a clearer understanding of instrumentation-related complaints and reoperations may lead to improvement in this surgeon-controlled variable.
There are limitations to this study. The data regarding clinical courses were collected by retrospective chart review, which has known limitations. To offset this, we collected prospective outcome data with use of the SF-12, the SRS-22R, and a spine-related complaints questionnaire. No control group was available for comparison of outcomes in our cohort. We used the SF-12 and previously published normative values for the SRS-22R for comparison with population norms. Such comparisons have inherent limitations, as the groups vary by sex and mean age; our cohort was primarily female and more than a decade older than the controls.
Only 35% of the patients who met the inclusion criteria had complete data that could be included in our analysis. Although there was no statistically significant difference in demographics between patients with and without follow-up data available, this low response rate could have introduced selection bias. Ideally, patients should have been seen in clinic, standing radiographs should have been taken, and pulmonary function tests should have been performed. However, these patients were asymptomatic, and ethical and insurance issues prevented those actions. Thus, any radiographic changes occurring over the intervening years, from the last clinic visit to completion of the surveys, were not documented. This situation may or may not have limited our findings, as other authors have found low correlation between radiographic outcomes and clinical outcome measures.13,14,19,36 During the period when these surgeries were performed, segmental spine instrumentation with hooks was the standard of care for deformity correction in AIS; therefore, all posterior instrumentations were done with hook-only segmental fixation. Current pedicle screw–based techniques that allow for additional correction of the deformity may provide different outcomes in the future.