Published online Sep 18, 2018. doi: 10.5312/wjo.v9.i9.138
Peer-review started: February 10, 2018
First decision: March 9, 2018
Revised: May 20, 2018
Accepted: May 23, 2018
Article in press: May 23, 2018
Published online: September 18, 2018
Scoliosis surgery is a major spinal procedure that is associated with significant risks of neurological and medical complications, producing permanent patient disability and increasing surgical morbidity. Surgical techniques have been developed in an attempt to standardize patient treatment and reduce the rate of operative complications. In recent decades, dual-rod instrumentation has become the standard of care for scoliosis correction. The introduction of segmental pedicle screws has allowed better coronal and axial deformity correction but has increased surgical risks. Single-rod correction techniques have been used in patients with adolescent idiopathic scoliosis (AIS) and Duchenne muscular dystrophy with controversial results in two previous series.
Single-rod correction techniques may offer advantages over dual-rod pedicle screw constructs, including reduced operative time and blood loss, lower risk of infection and instrumentation profile, easier surgical planning and operative technique, as well as reduced implant cost. In patients with major co-morbidities, such techniques may improve surgical safety and reduce associated morbidity and mortality of the procedure.
In this study, we reviewed demographic, radiographic, surgical, as well as quality of life data of 99 children and adolescents with scoliosis who underwent surgical correction using a single rod hybrid technique under the senior author. We report on the effectiveness of this technique in correcting the spinal deformity and focus on the rate of complications. We also analyzed the instrumentation costs in AIS and compared the single rod construct to previous series of patients treated in our practice with segmental pedicle screw dual instrumentation.
We prospectively collected data on 99 pediatric patients including review of patient records and spinal radiographs as well as assessment of quality of life questionnaires (SRS-22) in AIS patients both before and after surgery. We applied statistical analysis of our results where appropriate and compared the outcomes of the single rod technique to those that we had previously reported in the treatment of AIS using dual segmental pedicle screw constructs.
We included three groups of patients: Group A had 62 patients with complex deformities and low BMI associated with medical co-morbidities increasing the risk of cardiac, respiratory, and neurological complications, and intra-operative blood loss; group B had 21 patients previously treated with growing rod lengthenings who underwent definitive spinal fusion; group C had 16 patients with moderate AIS, low BMI, and severe eczema at risk of wound or systemic infection. Mean age at surgery was 12.8 years (SD 3.5 years). Mean scoliosis correction for the 99 patients was 62% (SD 15%) from 73° (SD 22°) to 28° (SD 15°). Mean surgical time was 153 min (SD 34 min), and blood loss was 530 mL (SD 327 mL); 20% blood volume (SD 13%). Mean clinical and radiological follow-up was 3.2 years (range: 2-12) post-operatively. Complications included rod failure, which occurred in three of our complex patients (group A) with severe syndromic or congenital kyphoscoliosis (3%). Only one of these three patients required revision surgery to address a non-union. Our revision rate was 2% (including a distal junctional kyphosis in a Marfan’s syndrome patient that required distal extension of the fusion).
The single-rod technique has achieved and maintained at follow-up good deformity correction associated with low surgical time, blood loss, and surgical morbidity. The use of lesser implants may reduce the instrumentation related risks, such as pedicle screw malposition, producing neurological, vascular, or visceral injury. The risk of wound infection may also be reduced as the volume of implants used in single rod instrumentation is much less than that in a dual rod/segmental pedicle screw construct. In our practice, this technique has a role primarily in pediatric patients with severe underlying co-morbidities and high surgical risks. The single rod technique has also reduced significantly the instrumentation cost compared to dual rod pedicle screw techniques, which is an important consideration at a time when health economics play an essential role in provision of patient care. Our complication rate is markedly lower than that reported in the two previous series of AIS or Duchenne muscular dystrophy patients with a low rate of re-operation (2%). We recorded high patient satisfaction among AIS patients and good functional outcomes that are comparable to our previous series of patients treated with dual rod/segmental pedicle screw instrumentation.
Despite the fact that the longest postoperative follow-up in our study was 12 years (mean follow-up: 3.2 years), we are monitoring our patients beyond skeletal maturity and well into adult life in order to confirm that no long-term complications occur. We believe that in light of this study the single rod technique is a reasonable alternative to dual rod techniques, especially in the treatment of complex patients with associated high morbidity. Further studies comparing outcomes of different techniques would be useful to determine the best option in different clinical scenarios and types of deformity.