Parallel Proximal Fixation in Rib-Based Growing Rod System: A Novel Approach to Deal With Proximal Anchor Migration

Early-onset scoliosis: a narrative review

Early-onset scoliosis (EOS) is defined as any spinal deformity that is present before 10 years old, regardless of etiology.

Deformity must be evaluated based on the intercorrelation between the lungs, spine, and thorax.

Curvatures of early-onset have increased risk of progression, cardiorespiratory problems, and increased morbidity and mortality.

Progression of the deformity may produce thoracic insufficiency syndrome, where a distorted thorax is unable to support normal respiratory function or lung growth.

Management and treatment of EOS should pursue a holistic approach in which the psychological impact and quality of life of the patient are also taken into consideration.

Growth-friendly surgical techniques have not met the initial expectations of correcting scoliotic deformity, promoting thoracic growth, and improving pulmonary function.

Novel Use of Subcostal Polyethylene Bands to Manage Tumor-Related Scoliosis Requiring Serial Imaging: A Case Report

CASE

A 16-year-old male patient with severe kyphoscoliosis, paraplegia, and neurogenic bowel/bladder caused by a juvenile pilocytic astrocytoma was treated surgically using a hybrid fusion construct with polyethylene bands after neoplasm resection. Owing to the necessity of serial postoperative magnetic resonance imaging studies to evaluate the recurrence of pathology and known effect of metal artifact from spinal instrumentation, preservation of radiographic resolution was critical.

CONCLUSION

We describe the novel utility of polyethylene bands placed around the ribs as a safe and effective form of hybrid construct for reducing radiographic metal artifact in spinal deformity cases requiring serial imaging.

Current status of the magnetically controlled growing rod in treatment of early-onset scoliosis: What we know after a decade of experience

The magnetically controlled growing rod (MCGR) has had approximately 10 years of clinical experience worldwide. Clinical effectiveness to control early-onset scoliosis is consistent even at final surgery. MCGRs have significantly lower relative percentage of infection or wound complications as compared to traditional growing rods. Most common complications include foundation failure and failure of distraction. Contouring of the rod especially at the proximal segment while accommodating for the straight actuator remains a difficult task and its failure may lead to proximal junctional kyphosis. Unique complications of MCGR include clunking, temporary diminishing distraction gains, and metallosis. Temporary reductions in distraction gains are observed as the MCGR lengthens but return to normal baseline distraction gains after rod exchange. Lack of standardization for rod configuration, distraction strategies and decisions of whether to keep the rods in situ, remove without fusion surgery or to perform spinal fusion at skeletal maturity will require further study.

Five or more proximal anchors and including upper end vertebra protects against reoperation in distraction-based growing rods

STUDY DESIGN

Retrospective multi-center enrollment.

OBJECTIVE

To examine the impact of patient and surgical factors on proximal complication and revision rates of early onset scoliosis patients using a multicenter database. Proximal anchor pullout and junctional kyphosis are common causes necessitating revision surgery during growth friendly treatment of early onset scoliosis (EOS). Many options exist for proximal fixation and may impact the rate of these complications.

METHODS

Retrospective review of multicenter database of patients with growth friendly constructs for EOS. Inclusion criteria were patients with index instrumentation < 10 years of age and minimum of 2 year follow-up.

RESULTS

353 patients met the inclusion criteria and had the following constructs: growing rods with spine anchors = 303; growing rods with rib anchors = 15 and VEPTR = 35. Mean age at index instrumentation was 6.0 years. Mean preoperative Cobb angle was 76° and mean kyphosis was 54°. Mean follow-up was 6.0 years. 21.8% of patients (77/353) experienced anchor pullout. Lower anchor pullout rates were associated with a higher numbers of proximal anchors (p = 0.003, r = - 0.157), and 5 or more anchors were associated with lower rates of anchor pullout (p = 0.014). Anchor type (rib hooks vs spine anchors vs rib cradle) did not impact rate of anchor pullout (p = 0.853). Kyphosis data was available for 198 patients. 23.2% (46/198) of these patients required proximal extension of their construct after index surgery. Initial instrumentation below the upper end vertebrae (UEV) of kyphosis was associated with higher rates of subsequent proximal revision; 28.9% (20/69) compared to 20.1% (26/129) for those instrumented at or above the UEV (p = 0.035). Preoperative kyphosis and change in thoracic kyphosis were not associated with anchor pullout (p = 0.436, p = 0.115) or proximal revision rates (p = 0.486, p = 0.401).

CONCLUSION

Five or more anchors are associated with lower rates of anchor pullout. Proximal anchor placement at or above the UEV resulted in a significant decrease in rates of proximal extension of the construct.