Optimal timing of starting growing rod treatment for early-onset scoliosis

BACKGROUND CONTEXT

Growing rod (GR) systems require periodical surgical intervention and may cause associated complications, as well as worsened sagittal plane deformity. Generally, the risk of complications decreases with an increment in age at the time of the index surgery with GR construct placement. However, the optimal timing to begin GR treatment has not reached a consensus yet.

PURPOSE

This study was performed to investigate the effect of age at the index GR surgery on the complication rates and formulate clinical guidelines for the optimal timing to begin GR treatment for EOS patients.

STUDY DESIGN

Kaplan-Meier analysis was used to determine complication occurrence as a function of the age at the index surgery and to determine the survival rates for the procedures. The receiver operator characteristic (ROC) curve was used to determine optimal cut-off values for the optimal timing of index surgery based on whether complications occurred or not.

PATIENT SAMPLE

54 patients who met the criteria were enrolled in this study.

OUTCOME MEASURES

The following spinal parameters were measured: major coronal Cobb angle, global kyphosis (GK), and coronal balance (CB). CB was defined as the horizontal distance from the C7 plumb line to the center sacral vertical line.

METHODS

All patients had completed GR treatment and had a minimum 1-year follow-up duration after the final surgical intervention. Patient data were collected as follows: age at the index surgery, gender, diagnosis, type of GR construct, and the number of lengthening procedures. The standing full-spine radiographs were obtained before and after the index surgery, before and after each lengthening procedure, before and after the final surgical intervention, and at the latest follow-up. Complications were categorized as implant, alignment, and general.

RESULTS

Kaplan-Meier analysis of complications demonstrated a declining trend in complication rates with increasing age at the index surgery. The absence of perioperative complications was targeted, we constructed the ROC curve and the cut-off value was 71.0 months. Age at the index surgery was therefore categorized into two groups: younger-age group (≤ 71.0 months) and advanced-age group (> 71.0 months). There was a higher complication rate for the younger-age group than versus the advanced-age group (61.5% vs 22.0%, p=.011). PJK as a major alignment-related complication, was more frequent in the younger-age group than in the advanced-age group (30.8% vs 4.9%, p=.025). But the advanced-age group exhibited significantly more severe deformities before GR surgery compared to the younger-age group.

CONCLUSIONS

This study shows that the elevated risk of complications observed in the younger-age group, which can be attributed to the younger age at the index surgery and the increased number of lengthening procedures during treatment. We suggest deferring the initiation of GR treatment until after the age of six years for EOS patients. We hope it will serve as a basis for GR technique in the treatment of EOS, with the ultimate goal of enhancing treatment outcomes for this challenging disorder.

Unilateral thoracic spinal nerve resection creates early onset thoracic scoliosis in an immature porcine model

PURPOSE

To test whether multiple-level unilateral thoracic spinal nerves (TSN) resection can induce the initial thoracic cage deformity to cause early onset thoracic scoliosis in an immature porcine model; and 2) to create an early onset thoracic scoliosis in a large animal model that can be used to evaluate growth-friendly surgical techniques and instruments in growing spine researches.

METHODS

Seventeen one-month-old pigs were assigned to 3 groups. In group 1 (n = 6), right TSN were resected from T7 to T14 with the contralateral (left) paraspinal muscle exposing and stripping. In group 2 (n = 5), the animals were treated in the same way except the contralateral (left) side was intact. In group 3 (n = 6), bilateral TSN were resected from T7 to T14. All animals were followed up for 17-weeks. Radiographs were measured and analyzed the correlation between the Cobb angle and thoracic cage deformity. A histological examination of the intercostal muscle (ICM) was performed.

RESULTS

In the groups 1 and 2, an average 62 ± 12° and 42 ± 15° right thoracic scoliosis with apical hypokyphosis of a mean - 5.2 ± 16° and - 1.8 ± 9° were created, respectively, during 17-weeks follow up. All curves were located at the operated levels with the convexity toward the TSN resection side. Statistical analysis demonstrated that the thoracic deformities were strongly correlated with the Cobb angle. In group 3, no scoliosis was created in any animal, but an average thoracic lordosis of - 32.3 ± 20.3° was seen. The histological examination showed the ICM denervation on the TSN resection side.

CONCLUSION

Unilateral TSN resection induced the initial thoracic deformity toward the TSN resection side resulting in thoracic hypokyphotic scoliosis in an immature pig model. This early onset thoracic scoliosis model could be used to evaluate the growth-friendly surgical techniques and instruments in future growing spine researches.

Anterior vertebral body tethering for idiopathic scoliosis in growing children: A systematic review

BACKGROUND

The management of idiopathic scoliosis (IS) in skeletally immature patients should aim at three-dimensional deformity correction, without compromising spinal and chest growth. In 2019, the US Food and Drug Administration approved the first instrumentation system for anterior vertebral body tethering (AVBT), under a Humanitarian Device Exception, for skeletally immature patients with curves having a Cobb angle between 35° and 65°.

AIM

To summarize current evidence about the efficacy and safety of AVBT in the management of IS in skeletally immature patients.

METHODS

From January 2014 to January 2021, Ovid Medline, Embase, Cochrane Library, Scopus, Web of Science, Google Scholar and PubMed were searched to identify relevant studies. The methodological quality of the studies was evaluated and relevant data were extracted.

RESULTS

Seven clinical trials recruiting 163 patients were included in the present review. Five studies out of seven were classified as high quality, whereas the remaining two studies were classified as moderate quality. A total of 151 of 163 AVBT procedures were performed in the thoracic spine, and the remaining 12 tethering in the lumbar spine. Only 117 of 163 (71.8%) patients had a nonprogressive curve at skeletal maturity. Twenty-three of 163 (14.11%) patients required unplanned revision surgery within the follow-up period. Conversion to posterior spinal fusion (PSF) was performed in 18 of 163 (11%) patients.

CONCLUSION

AVBT is a promising growth-friendly technique for treatment of IS in growing patients. However, it has moderate success and perioperative complications, revision and conversion to PSF.

Vertebral column growth in children with early onset scoliosis treated with magnetically controlled growing rods - Effects of distraction on vertebral and disc morphology

OBJECTIVES

To report changes in vertebral and disc morphology following treatment of early onset scoliosis (EOS) with magnetically controlled growing rods (MCGR).

METHODS

30 Patients, 21 girls and 9 boys, treated with MCGR for EOS were compared to a matched control group of 19 patients (12 girls, 7 boys) treated with bracing or observation. Age at surgery in the MCGR group was 8.75 (range: 4.6-11) years compared to 7.75 (range: 3.5-10.3) years in the control group at the time of onset of treatment. Mean follow-up was 45 (range: 24-65) months in the MCGR group vs 42 (range: 24-65) months in the control group. Calibrated radiographs were used to digitally measure disc height, vertebral body height, depth and width after surgery and at latest follow-up. Height, width and depth of lumbar and thoracic vertebrae and discs under distraction were compared to the control group and to vertebrae below instrumentation. T1-T12, T1-S1 length and Cobb angles were also measured.

RESULTS

(1) There is a significant increase of lumbar vertebral height under distraction. (2) Lumbar disc height as well as lumbar vertebral width within distraction is significantly reduced. (3) Depth of lumbar vertebrae is not significantly affected by distraction. (4) Morphology of thoracic vertebrae and adjacent discs is not significantly changed with distraction. (5) T1-T12 distance did not show any significant changes between surgical and control group, while T1-S1 growth was significantly reduced compared to the control group.

CONCLUSIONS

Significant changes of morphology of lumbar vertebra and discs are observed under distraction with MCGR compared to segments below instrumentation and the control group.

LEVEL OF EVIDENCE

Level III - retrospective comparative series.

Induction of a representative idiopathic-like scoliosis in a porcine model using a multidirectional dynamic spring-based system

BACKGROUND CONTEXT

Scoliosis is a 3D deformity of the spine in which vertebral rotation plays an important role. However, no treatment strategy currently exists that primarily applies a continuous rotational moment over a long period of time to the spine, while preserving its mobility. We developed a dynamic, torsional device that can be inserted with standard posterior instrumentation. The feasibility of this implant to rotate the spine and preserve motion was tested in growing mini-pigs.

PURPOSE

To test the quality and feasibility of the torsional device to induce the typical axial rotation of scoliosis while maintaining growth and mobility of the spine.

STUDY DESIGN

Preclinical animal study with 14 male, 7 month old Gottingen mini-pigs. Comparison of two scoliosis induction methods, with and without the torsional device, with respect to 3D deformity and maintenance of the scoliosis after removal of the implants.

METHODS

Fourteen mini-pigs received either a unilateral tether-only (n=6) or a tether combined with a contralateral torsional device (n=8). X-rays and CT-scans were made post-operative, at 8 weeks and at 12 weeks. Flexibility of the spine was assessed at 12 weeks. In 3 mini-pigs per condition, the implants were removed and the animals were followed until no further correction was expected.

RESULTS

At 12 weeks the tether-only group yielded a coronal Cobb angle of 16.8±3.3°For the tether combined with the torsional device this was 22.0±4.0°. The most prominent difference at 12 weeks was the axial rotation with 3.6±2.8° for the tether-only group compared to 18.1±4.6° for the tether-torsion group. Spinal growth and flexibility remained normal and comparable for both groups. After removal of the devices, the induced scoliosis reduced by 41% in both groups. There were no adverse tissue reactions, implant complications or infections.

CONCLUSION

The present study indicates the ability of the torsional device combined with a tether to induce a flexible idiopathic-like scoliosis in mini-pigs. The torsional device was necessary to induce the typical axial rotation found in human scoliosis.

CLINICAL SIGNIFICANCE

The investigated torsional device could induce apical rotation in a flexible and growing spine. Whether this may be used to reduce a scoliotic deformity remains to be investigated.

Complications of dual growing rod with all-pedicle screw instrumentation in the treatment of early-onset scoliosis

BACKGROUND

Treatment of early-onset scoliosis (EOS) is still a challenge to patients, families, and surgeons. Previous studies have indicated that EOS patients are at high risk for complications following growth-friendly surgery. This study was performed to evaluate the results and complications of all-pedicle screw dual growing rod instrumentation in the treatment of EOS.

METHODS

In an IRB-approved retrospective study, we searched the electronic medical records of our institution for all patients who underwent posterior spinal instrumentation for scoliosis between March 2014 and March 2017. Patients under the age of 10 at the time of surgery who were treated with a growth-friendly technique were then selected. Patients with incomplete records and less than 2 years of follow-up were excluded. Charts, operative notes, clinic visits, and radiographs were extracted. Radiographs were reviewed, and the main curve Cobb angle, thoracic kyphosis, pelvic tilt, pelvic incidence, sacral slope, and proximal junctional angles were measured. We specifically looked for any intra-operative or post-operative complications. Statistical analysis was performed to determine the risk factors of complications.

RESULTS

A total of 42 patients with a mean age of 4.8 ± 2.1 years (range, 1.5-8 years) were included in the final analysis. Patients were followed for a median of 34 months (range, 24-55). The major curve was corrected from a mean of 42.9° ± 10.7° to 28.8° ± 9.6° at the latest follow-up. Proximal junctional angles and thoracic kyphosis increased significantly during the follow-up period (both P values < 0.001). A total of 7 complications (17%) were observed. Four patients (10%) developed superficial surgical site infections, all of which resolved with antibiotics and one round of surgical debridement. Three cases (7%) of proximal junctional kyphosis (PJK) were encountered during the study period, none of which required revision surgery. Pre-operative thoracic kyphosis was the only significant risk factor for the development of PJK.

CONCLUSIONS

Our findings suggest that in settings without access to magnetically controlled growing rods, dual growing rods with all-pedicle screw instrumentation is still a viable treatment strategy with comparable results and complications. The most common complications are infection and PJK, with the latter being associated with a larger pre-operative thoracic kyphosis.

Early onset scoliosis and current treatment methods

OBJECTIVE

Provide an update of the management options for early onset scoliosis patients, including general assessment, conservative and surgical options.

METHODS

We included the updated information about the assessment and management options of Early Onset Scoliosis, taking into consideration the non-fusion methods, including the burden on the patient and their family.

RESULTS

With the heterogeneity of this population, it is difficult to get a consensus about a unified protocol for management. Accordingly, the surgeon dealing with these cases needs to be aware of the broad range of surgical and non-surgical methods when treating these patients.

CONCLUSION

The main aim of early onset scoliosis treatment is to gain a flexible spine associated with normal lung development and thoracic growth. Management needs to be individualized between the surgeon and patient in relation to the etiology and patient conditions.

Spine Deformity With Fused Ribs Treated With Proximal Rib- Versus Spine-Based Growing Constructs

STUDY DESIGN

Retrospective review of prospectively collected data.

OBJECTIVE

To compare the use of spine-based versus rib-based implants for the treatment of early-onset scoliosis (EOS) in the setting of rib fusions.

SUMMARY OF BACKGROUND DATA

Treatment for severe early-onset spinal deformity with rib fusions includes growing spine devices with proximal rib or spine anchors. The results of treatment, however, have not been compared between spine-based versus rib-based proximal anchors.

METHODS

169 patients with rib fusions treated with rib-based or spine-based constructs and minimum two-year follow-up were included. Sixteen patients were treated with proximal spine-based anchors and 153 with proximal rib-based devices (VEPTRs). Overall, 104 of the patients with rib-based fixation underwent thoracoplasty at the index surgery. We evaluated change in T1-T12 and T1-S1 height, coronal Cobb angle, kyphosis, and number of lengthening/revision surgeries.

RESULTS

Kyphosis increased a mean of 7° in the rib-based group and decreased a mean of 20 degrees in the spine-based group (p = .002). Major Cobb angle decreased in both groups (p < .0001); however, the spine-based group had greater Cobb angle improvement (24 vs. 11 degrees, p = .04). From implant and lengthening of distraction devices, there was a mean 3.3-cm (22%) increase in T1-T12 height and a mean of 8.0 lengthenings in the rib-based group compared with a 5.7-cm increase and 6.3 lengthening surgeries in the spine-based group. Patients with rib-based constructs had a mean of 11 total procedures, whereas spine-based patients had a mean of 8.

CONCLUSIONS

Patients underwent a mean of eight lengthening surgeries before final fusion or cessation of lengthening with a modest 2.3-cm increase in T1-T12 height. Compared with proximal rib anchors, proximal spine anchors controlled kyphosis and improved Cobb angle correction for early-onset scoliosis with rib fusions.

Radiographic Outcomes of Shilla Growth Guidance System and Traditional Growing Rods Through Definitive Treatment

STUDY DESIGN

Retrospective review of a multicenter database.

OBJECTIVES

To compare the radiographic outcomes of patients who had undergone the Shilla Growth Guidance System (SGGS) and traditional growing rod (GR) treatment for management of early-onset scoliosis (EOS) through definitive treatment.

SUMMARY OF BACKGROUND DATA

The efficacy of surgical treatment of EOS can only be determined after definitive treatment has been completed. We wanted to review our experience with the SGGS and GR for management of EOS through definitive treatment.

METHODS

Patients who had surgical treatment with SGGS or GR and had undergone definitive treatment were included. The patients were matched by age, preoperative curve magnitude, and diagnosis. The study population consisted of 36 patients (18 in each group) whose mean age at initial surgery was as follows: SGGS, 7.9 years; and GR, 7.7 years (not significant [NS]). Length of follow-up after initial surgery was 6.1 years for SGGS and 7.4 years for GR (NS). Definitive treatment was posterior spinal fusion (15 SGGS, 17 GR), implant removal (3 SGGS), or completion of lengthenings (1 GR).

RESULTS

The preoperative curve was 61 degrees for SGGS and 65 degrees for GR (NS). After index surgery, the major curve decreased to 24 degrees (-37 degrees) for SGGS and 38 (-27 degrees) for GR (p < .05). At last follow-up, the major curve was 34 degrees (44%) for SGGS and 36 degrees (45%) for GR (NS). The initial T1-T12 length for SGGS was 188 mm and for GR, 181 mm; at last follow-up, SGGS was 234 mm (46 mm increase) and GR was 233 mm (52 mm increase) (NS).

CONCLUSION

Our analysis shows the final radiographic outcomes (and changes) and complications (implant-related and infection) between the SGGS and GR groups were not statistically different. The main difference between the two groups was the threefold difference in overall surgeries.

Growing spine deformities: Are magnetic rods the final answer?

Treatment paradigms for Early Onset Scoliosis have changed from fusion to fusionless methods as the harmful effects of early fusion on the growing spine and thorax were realized. Magnetic rods are a recent addition to fusionless technology for controlling scoliosis in a growing spine. The clinical evidence base on magnet driven growth rods (MDGR) has accumulated over the last 4 years. It has implications for reduction in the number of repeat surgeries required with similar complications as the traditional growth rods (TGR) and at a higher initial cost. However in terms of patient psyche and avoidance of repeat surgeries which are necessary with the TGR, MDGR treatment works out less expensive in the long run with definitely better patient comfort. The authors look at the available literature coupled with their own experience to discuss the current status, limitations and future prospects for this type of technology.

Growing rod erosion through the lamina causing spinal cord compression in an 8-year-old girl with early-onset scoliosis

BACKGROUND CONTEXT

Early-onset scoliosis often occurs by the age of 5 years and is attributed to many structural abnormalities. Syndromic early-onset scoliosis is considered one of the most aggressive types of early-onset scoliosis. Treatment starts with serial casting and bracing, but eventually most of these patients undergo growth-sparing procedures, such as a single growing rod, dual growing rods, or a vertical expandable titanium prosthetic rib.

PURPOSE

This case report aimed to describe an unusual complication of erosion of a growing rod through the lamina that caused spinal cord compression in an 8-year-old girl with early-onset scoliosis.

STUDY DESIGN

This is a case report.

METHODS

A retrospective chart review was used to describe the clinical course and radiographic findings of this case after rod erosion into the spinal canal.

RESULTS

The patient underwent successful revision surgery removing the rod without neurologic complications.

CONCLUSIONS

Patients with syndromic early-onset scoliosis are more prone to progressive curves and severe rotational deformity. We believe that the severe kyphotic deformity in addition to the dysplastic nature of the deformity in this population may predispose them to this unusual complication.

Surgical outcomes by age at the time of surgery in the treatment of congenital scoliosis in children under age 10 years

BACKGROUND CONTEXT

There is little information regarding the surgical outcomes with regard to the timing of surgery in children under age 10 years for congenital scoliosis with a long-term follow-up.

PURPOSE

The purpose of this study was to compare the surgical outcomes for congenital scoliosis in children 6 years or older but less than 10 years of age.

STUDY DESIGN

This is a retrospective study.

PATIENT SAMPLE

Eighteen congenital scoliosis patients under age 10 years at the time of surgery were treated by posterior hemivertebra resection and bilateral pedicle screw fixation.

OUTCOME MEASURES

Outcome measures are radiological outcomes (plain radiographs and computed tomography) and complications.

METHODS

Eighteen congenital scoliosis patients (n=18) under age 10 years at the time of surgery were treated by posterior hemivertebra resection and bilateral pedicle screw fixation. These cases were retrospectively studied and had a minimum of 7-year follow-up. We assigned patients into two groups: Group 1 (n=9) patients who had surgery before 6 years of age and Group 2 (n=9) those who had surgery after 6 years of age.

RESULTS

The groups were not found to be statistically different in operative time, blood loss, and follow-up period. In the Group 1, the mean Cobb angle of the main curve was 32.4° before surgery, 6.4° after surgery, and 9.1° at last follow-up. In the Group 2, the mean Cobb angle of the main curve was 36.5° before surgery, 10.4° after surgery, and 14.5° at last follow-up. There was significantly better deformity correction of main curve immediate postoperatively and at last follow-up in Group 1. No significant difference was observed in growth rate of the vertebral body and spinal canal parameters comparing the two groups at the vertebra with or without screws. There was no crankshaft phenomena, no clinical or radiographic features suggestive of spinal stenosis during follow-up, and no major vascular or neurological complications related to the pedicle screws in either group.

CONCLUSIONS

In congenital scoliosis patients, posterior hemivertebra resection after pedicle screw fixation before the age of 6 years had significantly better deformity correction and did not cause a negative effect on the growth of vertebral body or spinal canal compared with the group treated after 6 years of age. Therefore, early surgical correction of a congenital hemivertebra in children under 6 years of age, before structural changes occur, effectively achieves a more satisfactory correction without causing iatrogenic spinal stenosis or neurologic complications compared with children older than 6 years but under 10 years of age.

Complications of surgical treatment of pediatric spinal deformities

Surgery in a child with spinal deformity is challenging. Although current orthopedic practice ensures good long-term surgical results, complications occur. Idiopathic scoliosis represents the most extensively investigated deformity of the pediatric spine. Nonidiopathic deformities of the spine are at higher risk for perioperative and long-term complications, mainly because of underlying comorbidities. A multidisciplinary treatment strategy is helpful to assure optimization of medical conditions before surgery. Awareness of complications that occur during or after spine surgery is essential to avoid a poor outcome and for future surgical decision making. This article summarizes the complications of surgical treatment of the growing spine.

Fusionless procedures for the management of early-onset spine deformities in 2011: what do we know?

While attempts to understand them better and treat them more effectively, early-onset deformities have gained great pace in the past few years. Large patient series with long follow-ups that would provide high levels of evidence are still almost non-existent. That there is no safe treatment algorithm defined and agreed upon for this patient population continues to pose a challenge for pediatric spine surgeons. In this review, authors who are well known for their research and experience in the treatment of early-onset scoliosis (EOS) have come together in order to answer those questions which are most frequently asked by other surgeons. The most basic eight questions in this field have been answered succinctly by these authors and a current overview is provided.