A comparison of three- and two-rod constructs in the correction of severe pediatric scoliosis

Abstract

Purpose: Managing severe scoliosis is challenging and risky with a significant complication rate regardless of treatment strategy. In this retrospective comparative study, we report our results using a three-rod compared to two-rod construct in the surgical treatment of severe spine deformities to investigate which technique is safer, and which provides superior radiological outcomes.

Methods: Forty-six consecutive patients undergoing posterior spine fusion for scoliosis between 2006 and 2017 were identified in our institutional records. Inclusion criteria were minimum coronal deformity of 90°, age < 18 years at the time of surgery and a minimum 2 years of follow-up. Radiographic and clinical parameters, as well as post-operative complications were compared between the two groups.

Results: There were 21 patients in the three-rod group and 25 in the two-rod group. The mean preoperative major coronal deformity was 100°± 9 and 102°± 10 in the three-rod and two-rod, respectively (p = 0.6). The average major curve correction was 51% and 59% in three-rod and two-rod groups, respectively (p = 0.03). The post-operative thoracic kyphosis was 30°± 11 and 21°± 12 in the three-rod and the two-rod groups, respectively (p = 0.01). The surgical time was 476 ± 52 and 387 ± 84 min in three-rod and two-rod, respectively (p < 0.01). One patient in the two-rod cohort showed permanent post-operative sensory deficit. There were three unplanned returns to operating theater in the two-rod group.

Conclusions: Coronal correction was better with two-rod, whereas sagittal balance was superior with three-rod. Both techniques achieved balanced spine treating severe scoliosis. The two-rod technique was associated with a higher likelihood of requiring revision surgery.

Level of evidence: level 3.

Keywords: Severe scoliosis; posterior column osteotomy; posterior spinal fusion; skeletal traction; three-rod technique.

Figure 1.

A 12.5-year-old boy with AIS. (a) Pre-operative anteroposterior radiographic showing 45° proximal thoracic, 108° main thoracic, and 66.3° lumbar scoliosis. (b) Pre-operative lateral radiograph showed 40° thoracic kyphosis and 53° lumber lordosis. (c) Anteroposterior radiograph with three-rod constructs at post-operative. The proximal thoracic curve was corrected to 31°, main thoracic curve to 37°, and lumber curve to 27°. (d) Lateral radiograph at post-operative. Thoracic kyphosis was 33° and lumber lordosis was 49°. AIS: adolescent idiopathic scoliosis.

Figure 2.

A 15.9-year-old boy with AIS. (a) Pre-operative anteroposterior radiographic showed 41° proximal thoracic, 92° main thoracic, and 57° lumbar scoliosis. (b) Pre-operative lateral radiograph showed 44° thoracic kyphosis and 59° lumber lordosis. (c) Anteroposterior radiograph with two-rod constructs and Smith-Peterson osteotomy at post-operative. The proximal thoracic curve was corrected to 16°, main thoracic curve to 19°, and lumber curve to 17°. (d) Lateral radiograph at post-operative. Thoracic kyphosis was 27° and lumber lordosis was 41°. AIS: adolescenr idiopathic scoliosis.