Idiopathic scoliosis : aspects on surgical and non-surgical treatment

Abstract

The term scoliosis has been used to describe conditions that lead to deformation of the spine. It derives from the ancient Greek ‘σκολίωσις’ and the root word ‘σκολιός’ which means ‘bent or crooked’. In its most common form, scoliosis is of unknown - idiopathic - cause and origin. It affects roughly 3% of children and adolescents during growth and in mild cases no treatment is required. In moderate cases, bracing has been proposed, with the aim to halt progression of idiopathic scoliosis. It is most common with full-time bracing using rigid, custom made thoracolumbosacral orthoses. It is worn for 16-20 hours per day until skeletal maturity and has been shown to prevent scoliosis progression to a surgical threshold in about 70% of the cases. However, compliance to the treatment has been one of the major drawbacks seen with the full-time brace. Therefore, night-time braces, worn only during the night, have started to gain popularity over the years. Nevertheless, evidence on the effectiveness of night-time bracing has only been based on retrospective studies. More recently, specific scoliosis exercise regimes consisting of self-mediated correction maneuvers in 3 dimensions have also emerged. So far, there has been only one high quality study showing effectiveness of this modality, in patients with mild idiopathic scoliosis.

A trial was performed consisting of 135 patients randomized to self-mediated physical activity in combination with either night-time brace, or scoliosis-specific exercise, or self-mediated physical activity alone. Night-time brace was shown to be more effective than self-mediated physical activity in preventing scoliosis progression. On the other hand, scoliosis-specific exercise did not show any clinical benefit when compared to the self-mediated physical activity. Additionally, comparison between the nigh-time brace group and a group of patients who declined participation in the trial and received a full-time brace showed similar effectiveness on the prevention of curve progression.

In case the deformity progresses to more severe curves, surgery may be suggested. Over the last decades, a posterior exposure to the spine with a high number of implants and predominantly pedicle screw based fixation techniques has been favored over traditional techniques with low number of implants for the correction of scoliosis. These techniques have been suggested to increase correction and fusion rates and eliminate the risks associated with exposure of the chest wall and/or abdomen in anterior approaches to the spine. Disadvantages of the posterior approach to the spine include extended muscle dissection, need for a higher number of vertebrae to be fused and risk for neurological injuries to the spinal cord. To date, whether posterior based fusion may result in better clinical and radiographic outcomes compared to anterior fusion is still unclear. Moreover, whether higher number of implants per vertebra (implant density) results in better clinical and radiographic outcomes is still debatable.

In a nationwide registry-based cohort, we identified patients who underwent anterior (n=27) and posterior (n=32) fusion surgery for a thoracolumbar/lumbar type of scoliosis. We found that despite a longer operative time in the anterior group and higher blood loss and longer fusion constructs in the posterior group, both procedures resulted in significant correction of the scoliosis with similar patient-reported outcome and satisfaction; suggesting that the type of approach is not related to health-reported quality of life.

By using the same nationwide database, we also identified 328 surgically treated idiopathic scoliosis patients who were then divided into tertiles based on the number of implants used per operated vertebra. We found no differences in the correction rate of the curve and health-reported quality of life in the different tertiles, suggesting that a high number of implants is not necessarily beneficial in the surgical treatment of idiopathic scoliosis.

Studies have shown that, what is perceived as successful radiographic outcome, may not necessarily correlate with patient´s own perception of successful outcome after surgery for idiopathic scoliosis. Patients may still experience persistent back pain and worse quality of life, despite an excellent radiographic outcome.

By using the same nationwide database, we identified 280 patients treated with posterior fusion surgery for idiopathic scoliosis and divided them into a high (n=67) and a low (=213) postoperative pain group, based on their self-reported postoperative back pain scores. We found that patients in the high pain group also reported higher back pain and worse quality of life before surgery, compared to the low postoperative pain group. High preoperative back pain and low preoperative mental health were identified as predictors of persistent pain after surgery.