Treatment of Early-Onset Scoliosis: Techniques, Indications, and Complications

Early-onset scoliosis (EOS) refers to a spinal deformity that presents before the age of 10 years. It is categorized into five types based on etiology: idiopathic, congenital, thoracogenic, neuromuscular, and syndromic. The treatment of EOS poses significant challenges for spine surgeons, as the primary goals are to minimize spinal deformity while maximizing thoracic volume and pulmonary function. This article provides a comprehensive review of the current treatments for EOS, focusing on advancements made in the last decade, including both conservative and surgical interventions.

Introduction

The understanding and management of EOS have evolved significantly due to the rapid expansion of medical knowledge in this field. The condition is complex, with varying etiologies and progression rates, making it difficult to establish a standardized classification system. However, a new classification system designed by experienced pediatric spine surgeons has been reported to have high levels of agreement and consistency. The treatment goals for EOS include creating a well-developed thoracic cavity, improving lung volume, and enhancing pulmonary function.

Conservative Treatments

Conservative treatments are often the first line of management for EOS. These include bracing, casting, halo-gravity traction (HGT), and physiotherapy. While these methods can achieve satisfactory correction in some patients, they are generally used to delay the need for surgery.

Serial Casting

Serial casting is considered the most effective conservative treatment for EOS. It involves the application of a plaster cast under general anesthesia, with derotational forces applied to correct the scoliosis. Casts are typically changed every 2 to 3 months, depending on the patient’s growth. Serial casting is indicated for curves greater than 25°, with documented progression, or a rib-vertebral angle difference greater than 20°. Studies have shown that serial casting can preserve growth potential and delay or even eliminate the need for surgery, particularly in patients with idiopathic scoliosis. However, the success rate is lower in non-idiopathic cases, and complications such as pressure sores, subclavian vein thrombosis, and even death have been reported.

Bracing

Bracing has been proven effective for adolescent idiopathic scoliosis, but its role in EOS is less well-established. Studies have shown that bracing can achieve significant correction and stabilization in patients with infantile or juvenile scoliosis. However, the follow-up durations in these studies have been relatively short, and more research is needed to validate the long-term efficacy of bracing for EOS.

Halo-Gravity Traction (HGT)

HGT is commonly used as an adjunctive treatment, particularly in patients with severe and rigid curves, scoliosis associated with kyphosis, or those with decreased pulmonary or nutritional status. It is often combined with other treatments, such as surgery, to improve correction and reduce the risk of complications.

Physiotherapy

Physiotherapy for idiopathic scoliosis in skeletally immature children remains controversial. While some studies suggest that physiotherapy can help manage the condition, further validation is needed to confirm its efficacy.

Surgical Treatments

When conservative treatments fail or are insufficient, surgical interventions are indicated. The primary goal of surgical treatment is to correct the spinal deformity while preserving growth potential and pulmonary function. Surgical techniques for EOS are generally categorized into three types based on the amount of correction force applied: distraction-based, compression-based, and growth-guided systems.

Distraction-Based Systems

Distraction-based systems apply a mechanical distractive force on the spine segments, ribs, and/or pelvis. These include traditional growing rods (TGRs), magnetically controlled growing rods (MCGRs), and vertical expandable prosthetic titanium ribs (VEPTRs).

Traditional Growing Rods (TGRs)

TGRs are the most commonly applied technique and are considered the gold standard for EOS with long curves. The technique involves the insertion of dual rods with proximal and distal instrumentation and fusion. Lengthening procedures are performed every 6 to 12 months to preserve growth potential. The initial correction rate varies from 30% to 60%, but the complication rate is high, with reports of implant failure, infections, and wound healing problems. Risk factors for complications include younger age at initial surgery, single-rod constructs, longer lengthening intervals, and subcutaneous rod placement.

Magnetically Controlled Growing Rods (MCGRs)

MCGRs offer a less invasive alternative to TGRs, as they do not require open lengthening procedures. Instead, the rods are lengthened using an external remote control. The correction rate with MCGRs is similar to that of TGRs, but the rate of infections and wound healing problems is lower. However, MCGRs are associated with a higher risk of metalwork problems and unplanned revisions. The technique is still relatively new, and further studies with larger sample sizes and longer follow-up durations are needed.

Vertical Expandable Prosthetic Titanium Ribs (VEPTRs)

VEPTRs are primarily indicated for patients with thoracic insufficiency syndrome (TIS) but are sometimes used in EOS patients at risk for secondary TIS. The complication rate with VEPTRs is extremely high, which limits their application.

Compression-Based Systems

Compression-based systems apply a compressive force to the convex side of the deformity, leading to growth inhibition on the ipsilateral side. These include vertebral body stapling (VBS) and vertebral body tethering (VBT).

Vertebral Body Tethering (VBT)

VBT involves the use of a flexible spinal implant that prevents the progression of the deformity during growth spurts. The procedure is performed through an endoscopic approach, and the correction is achieved by tensioning the tether and translating the spine. VBT is indicated for thoracic curves between 30° and 70° and thoracolumbar or lumbar curves from 30° to 60° in skeletally immature patients. The complication rate is relatively low, but overcorrection can occur.

Vertebral Body Stapling (VBS)

VBS uses nitinol C-shaped staples to inhibit spinal growth on the convex side while preserving motion segments. The technique is indicated for idiopathic scoliosis with a Risser sign of 0–2 and a degree of curvature of 25° to 40°. The complication rate is moderate, with reports of staple movement, broken staples, and overcorrection.

Growth-Guided Systems

Growth-guided systems anchor the end and apical vertebrae, allowing the spine to slide along the rod. These include the Shilla growth guidance system (SGGS) and the modern Luque trolley (MLT).

Shilla Growth Guidance System (SGGS)

The SGGS corrects the apical deformity and guides spinal growth toward a normal alignment. The technique avoids multiple open lengthening surgeries, reducing the risk of surgical scarring and infections. However, the complication rate is high, with reports of implant-related problems and apex migration.

Modern Luque Trolley (MLT)

MLT is a newer technique that allows for normal spinal growth while preventing the progression of spinal deformities. The technique involves gliding spinal anchors that travel along fixed, overlapping rods. The complication rate is unknown, as the technique is still in its early stages of development.

Posterior Dynamic Deformity Correction (ApiFix)

ApiFix is a newer, less invasive device that involves fewer instrumented segments and preserves growth potential without spinal fusion. The device is inserted on the concave side of the curve and allows for dynamic correction through specific exercises. However, there are few studies on ApiFix, and its long-term efficacy is still unknown.

Osteotomy and Short Fusion

For congenital scoliosis caused by a single hemivertebra, hemivertebra resection and short segmental fusion are the gold standard. The procedure involves the resection of the hemivertebra and bisegmental fusion, achieving significant correction of the deformity. However, the risk of complications, such as wound healing problems and screw displacement, is higher in young patients with poor bone quality.

Hybrid Technique

For EOS patients with severe rigid deformities, a hybrid technique combining one-stage posterior osteotomy with short segmental fusion and dual growing rods may be a good choice. This technique improves correction and decreases the incidence of implant failures while preserving lung growth. The complication rate is high, but the technique offers a promising alternative for managing severe EOS.

Complications

The treatment of EOS is associated with a high complication rate, regardless of the technique used. Complications include implant failure, infections, wound healing problems, neurological impairment, and overcorrection. The risk of complications is influenced by factors such as the patient’s age, the type of technique used, and the duration of treatment. Adequate informed consent and close follow-up are essential to managing these complications.

Conclusion

The treatment of EOS is complex and requires a multidisciplinary approach. Conservative treatments, such as serial casting and bracing, can be effective in some cases, but surgical intervention is often necessary. Surgical techniques vary depending on the patient’s characteristics, the surgeon’s experience, and the specific needs of the case. Despite the high complication rate, advancements in surgical techniques and a better understanding of the condition offer hope for improved outcomes in the future.

doi.org/10.1097/CM9.0000000000000614

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