Fusionless instrumentation systems for congenital scoliosis: expandable spinal rods and vertical expandable prosthetic titanium rib in the management of congenital spine deformities in the growing child

The Evaluation of Serum Metal Ion Levels and Metallosis in Graduated Patients With Magnetically Controlled Growing Rods

BACKGROUND

Magnetically controlled growing rods (MCGR) aim to control curve progression while limiting surgical burden in children with early-onset scoliosis. Systemic and local distribution of metal debris has been documented in children with spinal implants. The aim of the study was to assess serum metal ion levels and local metal debris-related changes at the conclusion of MCGR treatment.

METHODS

Between February 2019 and September 2022, all patients who had a conversion to definitive fusion at the completion of MCGR treatment in our institution were invited to participate in this study. Consenting patients had serum metal ion levels drawn (titanium, cobalt, and chromium) and histologic analyses of peri-implant tissue samples.

RESULTS

We enrolled 24 children who underwent definitive fusion post-MCGR treatment for early-onset scoliosis. The average age at definitive fusion was 13.3 years (range: 11 to 17 y). The average length of MCGR treatment was 4.8 years (range: 1.5 to 6.8 y). At the end of the MCGR treatment, 23 (96%) patients had elevated serum metal ion levels. Mean serum titanium levels were 165.4 nmol/L (range: 30 to 390 nmol/L), mean serum cobalt levels were 4.6 nmol/L (range: 1.2 to 14 nmol/L), and mean serum chromium levels were 14 nmol/L (range: 2.4 to 30 nmol/L). Peri-implant soft tissue histologic analysis demonstrated local metal debris and foreign body reactions in all patients.

CONCLUSIONS

At the completion of MCGR treatment, the majority of patients demonstrate elevated serum metal ion levels and local metal debris-related peri-implant soft tissue changes. Although there is no current literature to suggest these findings are harmful, further research as to the clinical significance is required.

LEVEL OF EVIDENCE

Level IV.

Developments in Congenital Scoliosis and Related Research from 1992 to 2021: A Thirty-Year Bibliometric Analysis

BACKGROUND

Many studies, mainly original articles and reviews, have been reported on congenital scoliosis (CS), but there is a lack of bibliometric analyses. This study aimed to systematically analyze the developments and focuses in CS and related research fields.

METHODS

Data were retrieved from the Web of Science Core Collection database, and the top 100 most-cited studies were analyzed emphatically. The Web of Science Results Analysis and Citation Report was used to analyze different aspects of the literature. CiteSpace was used to analyze the cooperation network, reference co-citation, burst keywords, and burst citations.

RESULTS

The final analysis included 749 studies. CS and related research has been rapidly expanding. Several journals have published relevant studies and most-cited studies on this topic. Cooperation was noted among authors, institutions, and countries/regions in multiple instances. Surgical techniques (hemivertebra resection/posterior vertebral column resection/vertical expandable prosthetic titanium rib/double approach/grade 4 osteotomy) was one of the most common research focuses. In addition, research on genetics and molecular biology related to CS has become an emerging trend as a result of advances in basic science.

CONCLUSIONS

Over time, research on CS and in related fields has gained greater attention and has been expanding continuously, showing a trend toward globalization. We recommend that researchers focus on the progress of surgical techniques, advances in molecular biology and genetics, and characteristics of CS. The top clusters, most-cited articles, and references with the strongest burst citations should be studied further.

Rib-based Distraction Device Implantation Before Age 3 Associated With Higher Unplanned Rate of Return to the Operating Room

BACKGROUND

Surgical treatment of early-onset scoliosis (EOS) with rib-based implants such as the vertical expandable prosthetic titanium rib (VEPTR) is associated with a high rate of complications including surgical site infection, skin breakdown, and implant migration. Many of these complications warrant the need for unplanned reoperations, increasing the burden on an already vulnerable patient population, and introducing the further risk of infection. To provide insight into the risks of early intervention, we investigate the relationship between initial device implantation before the age of 3 and the rate of unplanned reoperation.

METHODS

A retrospective review was performed of all patients at a single institution who had undergone VEPTR insertion for EOS with at least a 2-year follow-up from 2007 to 2016. Patients were stratified into the case-cohort (0 to 2 y of age) or the comparison cohort (3 to 10 y of age) based on age at the time of device implantation. Multivariate regression accounting for age and scoliosis etiology was performed to identify factors predictive of unplanned reoperation.

RESULTS

A total of 137 of 185 patients treated with VEPTR were identified with 76 (56%) undergoing at least 1 unplanned reoperation during the study time period. There were 68 and 69 patients in the age 0- to 2-year and 3- to 10-year cohorts, respectively. Patients aged 0 to 2 years underwent a higher number of total procedures compared with those aged 3 to 10 (13.1±6.5 vs. 10.6±4.8, P=0.032). A significant difference was found in the rate of unplanned reoperation between the 2 cohorts with 44 (65%) patients aged 0 to 2 and 32 (46%) patients aged 3 to 10 undergoing at least 1 unplanned reoperation (P=0.031). Binary logistic multivariate regression accounting for age and scoliosis etiology demonstrated that patients aged 0 to 2 had a significantly greater odds of undergoing an unplanned reoperation (odds ratio=3.050; 95% confidence interval: 1.285-7.241; P=0.011) compared with patients aged 3 to 10 years.

CONCLUSION

Overall, EOS patients aged 0 to 2 at initial VEPTR implantation are up to 3 times higher risk of undergoing an unplanned reoperation compared with those aged 3 to 10.

LEVEL OF EVIDENCE

Level III.

Efficacy of distal pedicle screw fixation as a caudal foundation in VEPTR growing rod constructs for early onset scoliosis

PURPOSE

Surgical treatment of Early Onset Scoliosis (EOS) is challenging. Stable and robust foundations are vital. We have assessed a small cohort of patients with a rib-based proximal fixation and a pedicle screw-based distal foundation for a distraction based growing rod system.

METHOD

This is a single center study in a tertiary spinal deformity unit with a catchment population of over 6 million. We performed a retrospective radiographic evaluation of 15 patients with EOS treated with Vertical Expandable Titanium Prosthetic Rib (VEPTR) implant between 2007 and 2017. The review of medical records and imaging data was performed to identify growth of the spine and complications with pedicle screws.

RESULTS

There were ten male and five female patients with an average age at index surgery of 4yrs 11 months. Mean length of follow-up was 6 yrs 9 months. Serial radiographs revealed improvements in mean Cobb angle of 12 degrees, T1-T12 height of 29 mm and T1-S1 height of 48 mm with no deterioration in distal LIV tilt angle. We report that none of these patients had any complications related to their pedicle screws including cut-out.

CONCLUSION

We report a technique which is efficacious and provides a mechanically robust distal fixation for VEPTR lengthening in early onset scoliosis.

Understanding the implant performance of magnetically controlled growing spine rods: a review article

PURPOSE

Early-Onset Scoliosis (EOS) (defined as a curvature of the spine ≥ 10° with onset before 10 years of age) if not properly treated, can lead to increased morbidity and mortality. Traditionally Growing Rods (TGRs), implants fixated to the spine and extended every 6-8 months by surgery, are considered the gold standard, but Magnetically Controlled Growing Rods (MCGRs) avoid multiple surgeries. While the potential benefit of outpatient distraction procedure with MCGR is huge, concerns still remain about its risks, up to the release of a Medical Device Alert (MDA) by the Medicines and Healthcare Regulatory Agency (MHRA) advising not to implant MCGRs until further notice. The aim of this literature review is to (1) give an overview on the use of MCGRs and (2) identify what is currently understood about the surgical, implant and patient factors associated with the use of MCGRs.

METHODS

Systematic literature review.

RESULTS

Surgical factors such as use of single rod configuration or incorrect rod contouring might affect early failure of MCGRs. Patient's older age and higher BMI are correlated with rod slippage. Wear debris and distraction mechanism failure may result from implant design and iteration.

CONCLUSION

Despite the complications reported, this technology still offers one of the best solutions to spine surgeons dealing with severe EOS. Lowering the complication rate by identifying risk factors for failure is possible and further studies in this direction are required. Once the risk factors are well described, some of these can be addressed enabling a safer use of MCGRs.

Similar surgical outcomes of the growing rod technique for treatment of early-onset scoliosis with versus without untreated intraspinal anomalies

OBJECTIVE

The aim of this study was to compare the radiological and clinical outcomes of early-onset scoliosis (EOS) patients with or without intraspinal anomalies (IAs) managed with growing rods (GRs), and to evaluate the safety of the GR technique in EOS patients with untreated IAs.

METHODS

EOS patients undergoing GR placement between August 2008 and July 2017 were retrospectively reviewed. Patients with untreated IAs were classified into the EOS+IA group, and those without IAs into the EOS-IA group. The radiographic parameters including Cobb angle of the major curve, T1-S1 height, and apical vertebral translation were measured, and a detailed assessment of the neurological status was performed at each visit.

RESULTS

Seventy-six patients with EOS (32 boys, 44 girls) with an average age of 6.5 ± 2.3 years at initial surgery satisfied the inclusion and exclusion criteria, including 28 patients in the EOS+IA group and 48 patients in the EOS-IA group. The radiographic measurements were comparable between groups preoperatively, postoperatively, and at the latest follow-up. One patient in the EOS+IA group experienced sensory deficit in a unilateral lower extremity after initial surgery, and an intraoperative neurophysiological monitoring event was observed in a patient in the EOS-IA group. No permanent neurological deficit was observed in either group.

CONCLUSIONS

EOS patients with and those without IAs had comparable clinical and radiological outcomes of the GR technique. Repeated lengthening procedures may be safe for EOS patients with untreated IAs.

Clinical and health-related quality-of-life outcomes after early and late spinal fusion in pediatric patients with congenital scoliosis at 10-year follow-up

STUDY DESIGN

A retrospective comparative study.

OBJECTIVE

This study compares the effect of age at the time of surgery on clinical and health-related quality-of-life (HRQoL) outcomes at 10-year follow-up in pediatric patients with congenital scoliosis (CS). Several studies have evaluated the outcomes of surgical treatments of CS during the growth period; however, age at surgery and its long-term effects have been assessed in only a few case reports.

METHODS

We enrolled patients with CS who underwent spinal fusion at the age of 18 years or younger in our study. We evaluated 97 patients (38 males, 59 females; average age 16.5 years) who met our inclusion criteria, including the availability of outcome data for a minimum of 10-year post-surgery. We divided patients into two groups in terms of the age at surgery: early fusion (EF) and late fusion (LF) groups. Clinical outcomes included re-operations, major curve corrections immediately and at 10-year follow-up, Scoliosis Research Society (SRS)-22 questionnaire, and percentage forced vital capacity (%FVC).

RESULTS

The EF group (33 patients) and the LF group (64 patients) did not differ significantly in terms of demographics. In all domains, the EF group had better HRQoL than the LF group. More patients (52%) in the EF group required re-operation than in the LF group (23%). In addition, patients with short fusion (< 7 segments, p = 0.0011) and greater T1-T12 height (≥ 22 cm, p = 0.0088) had better %FVC than their counterparts.

CONCLUSIONS

Age at surgery might have some non-negligible impacts on patients' HRQoL and clinical outcomes. Our study highlighted the important factors in surgical considerations of choosing the appropriate timing for spinal fusion, performing shorter fusions, and achieving an acceptable curve correction without allowing further curve progression that required re-operations.

LEVEL OF EVIDENCE

Level III.

Treatment of early-onset scoliosis: techniques, indications, and complications

The treatments for early-onset scoliosis (EOS) remain great challenges for spine surgeons. This study aimed to comprehensively review the treatments for EOS, especially the advancements made in the last decade. Current studies on EOS were retrieved through a search on PubMed, UpToDate, the Web of Science Core Collection and Scopus were reviewed. The most pertinent information related to the current treatments for EOS was collected. The foci of treatments for EOS have included creating a well-developed thoracic cavity, improving lung volume, and improving pulmonary function. Conservative treatments include bracing, casting, halo-gravity traction, and physiotherapy. Serial casting is the most effective conservative treatment for EOS. Surgical treatments mainly include growth-friendly techniques, which are generally classified into three types according to the amount of correction force applied: distraction-based, compression-based, and growth-guided. The distraction-based systems include traditional or conventional growing rods, magnetically controlled growing rods, and vertical expandable prosthesis titanium ribs. The compression-based systems include vertebral body stapling and tethering. The growth-guided systems include the Shilla system and modern Luque trolley. In addition, some newer techniques have emerged in recent years, such as posterior dynamic deformity correction (ApiFix). For EOS patients presenting with sharp deformities in a long, congenital spinal deformity, a hybrid technique, one-stage posterior osteotomy with short segmental fusion and dual growing rods, may be a good choice. Hemivertebra resection is the gold standard for congenital scoliosis caused by single hemivertebra. Although the patient's growth potential is preserved in growth-friendly surgeries, a high complication rate should be expected, as well as a prolonged treatment duration and additional costs. Knowledge about EOS and its treatment options is rapidly expanding. Conservative treatments have specific limitations. For curves requiring a surgical intervention, surgical techniques may vary depending on the patients' characteristics, the surgeon's experience, and the actual state of the country.

Contouring the magnetically controlled growing rods: impact on expansion capacity and proximal junctional kyphosis

OBJECTIVE

To quantitatively determine the relationship between the contouring of the magnetically controlled growing rods (MCGR), their expansion capacity and the risk of developing proximal junctional kyphosis in early onset scoliosis (EOS). MCGRs allow gradual expansion and correction of the spinal deformity in EOS while reducing the need for repeated surgeries. As the expansion of the MCGRs is controlled externally, several factors can impact the discrepancy between the intended and actual expansions of the rods. The expansion capacity of the growing rods as a function of the expanded length has been tested in experimental setups; however, no study has evaluated the role of contouring of the MCGRs on its function and long-term surgical outcome.

METHODS

A total of 25 EOS patients, a total of 48 MCGRs, with right thoracic curves, were studied retrospectively. All patients had two view spinal radiographs at pre-operative, after MCGR implantation, and after 6 lengthening visits. The first post-operative radiographs were used to calculate the 3D contour of the MCGR at the proximal end. 2D ultrasound images before and after lengthening visits were used to measure the rod lengthening at each visit. The relationship between the increase in the rod length and rod curvature was determined. Finally, the rod curvature was correlated to the changes in proximal junctional kyphosis (PJK) angle between the pre-operative and the most recent follow-up, i.e., after 6 visits.

RESULTS

The average rod 3D angle at the proximal end was 13.5° ± 9.7° [0°-37.2°]. The overall increased length after six lengthening visits for the rod at the concave side was 18.8 mm and at the convex side was 16.9 mm. 62% of the patients with a contoured rod at the proximal end developed a PJK exceeding 10° whereas in patients with a straight rod PJK occurred in 9.1%.

CONCLUSIONS

Contouring the MCGR impacts both the mechanics of the rod expansion and the prevalence of PJK in EOS patient population.

Prospectively collected surgeon indications for discontinuation of a lengthening program for early-onset scoliosis

INTRODUCTION

At some point after children with early-onset scoliosis (EOS) undergo implantation of a distraction construct to control deformity and promote growth, a decision is made to discontinue lengthening. The purpose of this study was to evaluate surgeon indications for discontinuation of a lengthening program and to evaluate patient outcomes.

METHODS

As a part of a multicenter database, surgeons prospectively completed a questionnaire at the completion of growth-friendly treatment. Surgeon indications for discontinuation included patient age, pain/functional status, implant status, and spinal deformity parameters. Patient demographics, scoliosis type, deformity parameters, and length of time in a growing program were queried. Patients were treated with a final fusion or observation, and rate of secondary surgeries was analyzed.

RESULTS

Questionnaires were completed on 121 patients (61% female). EOS etiology was 31% neuromuscular, 43% congenital, 16% idiopathic, and 10% syndromic. Average age at initiation of growing program was 6.8 ± 3.1 years, and average age at discontinuation was 12.7 ± 2.5 years. The most commonly cited indications for discontinuation of a lengthening program included bone age/skeletal maturity (n = 46), patient age (n = 33), and diminishing returns with expansions (n = 33). A larger coronal Cobb angle was found in patients who underwent definitive fusion (65°) when compared with continued observation (55°, p = 0.001). Twenty-nine (24%) patients were initially treated with observation after completion of a growing construct. In this subgroup, at a minimum of 2 years' (average 3.8 years') follow-up, 26/29 (90%) patients remained stable with observation alone; whereas, three (10%) underwent delayed final fusion surgery.

CONCLUSIONS

The most common surgeon-cited indications for discontinuation of a lengthening program in EOS patients are skeletal maturity and patient age. The majority of patients (76%) underwent definitive spinal fusion after discontinuation of a lengthening program; whereas, those treated with observation alone had a survivorship of 90% at a minimum follow-up of two years.

Radiographic Outcome and Complication Rate of 34 Graduates After Treatment With Vertical Expandable Prosthetic Titanium Rib (VEPTR): A Single Center Report

BACKGROUND

The final strategy for graduates from growth-sparing surgery is challenging. The purpose of this study was to evaluate the radiographic outcome and complications of patients with early onset scoliosis (EOS) who have graduated from vertical expandable prosthetic titanium rib (VEPTR) treatment, either undergoing final fusion surgery or following a nonfusion approach.

METHODS

Final treatment for VEPTR graduates was divided in "VEPTR in situ without final fusion," "removal of VEPTR without final fusion," and "removal of VEPTR with instrumented final fusion." Radiographic evaluations included main coronal Cobb angle and main kyphosis pre and post VEPTR implantation, at the end of implant lengthening, after final fusion (if applicable), and at latest follow-up. Complications during VEPTR treatment and in case of final fusion were reported.

RESULTS

In total, 34 VEPTR graduates were included; 17 underwent final fusion surgery, and 17 followed a nonfusion strategy. Average coronal Cobb angle before VEPTR implantation was 70±23 degrees (range, 21 to 121 degrees), and 65±22 degrees (range, 17 to 119 degrees) at latest follow-up. Average main kyphosis angle was 53±27 degrees (range, 6 to 137 degrees) before VEPTR, and 69±34 degrees (range, 10 to 150 degrees) at latest follow-up. There was a 41% complication rate with final fusion surgery.

CONCLUSIONS

There is a high complication rate during VEPTR treatment and with final fusion surgery. The stiffness of the spine and thorax allow for only limited correction when performing a final instrumented spondylodesis. Avoiding final fusion may be a viable alternative in case of good coronal and sagittal alignment.

LEVEL OF EVIDENCE

Level IV-therapeutic.

Brace treatment can serve as a time-buying tactic for patients with congenital scoliosis

Background

Infantile patients with congenital scoliosis (CS) can be confronted with increasing risk of mortality and morbidity. To date, the effectiveness of conservative treatment in CS has not been sufficiently investigated. We aimed to evaluate the bracing outcome in patients with CS and to investigate whether wearing brace can effectively delay the surgical procedures.

Methods

A total of 39 braced CS patients including 25 boys and 14 girls were reviewed for the eligibility to be included in this study. Radiographic parameters including curve magnitude and T1 to T12 height were evaluated for each patient at the initiation of the treatment and at the final follow-up (FU), respectively. Duration of the follow-up and requirement of surgical interventions were also recorded. The student t test was used to compare the radiographic parameters between the initial visit and the last FU.

Results

The mean initial age at bracing was 4.1 ± 2.3 years, and 7.5 ± 1.8 brace modifications were performed during a mean FU period of 42.1 ± 26.5 months. The mean curve magnitude before bracing was 44.1 ± 12.2°, which was corrected to 41.3 ± 13.5° at the final visit (p = 0.33). T1-T12 height increased from 13.4 ± 2.5 to 17.1 ± 2.8 cm during the treatment (P < 0.001). Nine patients underwent surgical intervention due to the curve progression more than 5°, with the time of surgery delayed for 32.1 ± 18.2 months.

Conclusions

Brace treatment is an effective time-buying modality for CS patients, which may help maintain the body growth and delay the surgical intervention.

Maximal Force Generated by Magnetically Controlled Growing Rods Decreases With Rod Lengthening

OBJECTIVES

To evaluate the maximal force generated by magnetically controlled growing rods (MCGRs) at three different lengthened positions.

SUMMARY OF BACKGROUND DATA

The introduction of MCGRs has been met with great enthusiasm by surgeons managing early-onset scoliosis. These devices offer the potential to decrease the cost and morbidity associated with repeated surgeries, compared to traditional growing rods. One potential negative consequences of growing rod treatments is the law of diminishing returns, where the spine length gained decrease with each subsequent lengthening. The cause of this phenomenon is unknown and probably multifactorial, yet it may be affected by the strength of the lengthening mechanism in the MCGRs.

METHODS

Twelve MCGRs (90-mm actuator length) were obtained and tested to evaluate the maximal force generated at different lengths. The maximal lengthening force measured in pounds-of-force generated by each rod was recorded at expansion lengths of 0, 25, and 40 mm. Longitudinal analysis was performed using mixed effects linear regression to account for repeated measures and variability between individual implants.

RESULTS

At 0 mm of actuator lengthening, the mean maximum force was 46.8 lb (standard deviation [SD] 2.06, range 43-50). At 25 mm of expansion, the mean maximum force was 44.9 lb (SD 2.48, range 39.4-49.5). At 40 mm of lengthening, the mean maximum force was 43.2 lb (SD 5.56, range 27.3-49.1). In the mixed effects linear model, there was a statistically significant decrease in the maximal force generated with progressive MCGR lengthening, at an average decrease of 0.089 lb of force (95% CI, 0.030-0.148; p = .003) per millimeter of lengthening.

CONCLUSION

There is a small but statistically significant decrease in the maximal force generated by MCGR as the rods are lengthened. The decrease in force generated may result in diminished spine length gained with each subsequent MCGR lengthening.

LEVEL OF EVIDENCE

Level IV.

Long-term Outcome of Early Fusions for Congenital Scoliosis

STUDY DESIGN

The current literature on outcomes of early fusions for early-onset scoliosis (EOS) has a short follow-up of 7.7 to 12.5 years, with many patients not at the end of growth. The forced vital capacity (FVC) at follow-up ranged from 40.8% to 64% of predicted. A study was undertaken to evaluate the long-term outcome of these fusions.

METHODS

The study is of congenital patients who had a fusion under age 8 years, with the current age being >20 years. A follow-up consisting of radiographs, outcome questionnaires, and pulmonary function tests was performed. Of the 42 patients identified, 20 were traced and 11 agreed to participate, and completed all the data. The average follow-up was 37 years. All the fusions included the thoracic spine, with an average of 10.2 levels fused, of which an average of 8.8 levels were thoracic.

RESULTS

The average scoliosis at presentation was 52°, 56° at surgery and 47° at follow-up. At follow-up, the average FVC was 53% of predicted, with an average PaO₂ of 86 and PaCO₂ of 44 mm Hg. The mean T1-T12 length was 20 cm. There was no correlation of the FVC percentage predicted and the proximal extent of the fusion, the T1-T12 length or the number of thoracic levels fused. The average ODI was 23. On the SF36, the average Physical Component t score was 50; with the average Mental Component t score was 52.

CONCLUSION

At a long-term average follow-up of 37 years, the patients had a low FVC of 53%, with one on permanent oxygen and 5 with dyspnea. The patients were functioning well at follow-up, but it is unknown what their function would be without surgery or with longer follow-up.

Early-Onset Scoliosis: Updated Treatment Techniques and Results

STUDY DESIGN

This is a review of the current literature on early-onset scoliosis (EOS) techniques and treatment written by the Growing Spine Committee of the Scoliosis Research Society.

OBJECTIVES

The Growing Spine Committee of the Scoliosis Research Society sought to update the information available on the definition and treatment of EOS, including new information about existing techniques.

SUMMARY OF BACKGROUND DATA

EOS represents a diverse, heterogeneous, and clinically challenging group of spinal disorders occurring in children under the age of 10. Our understanding of EOS has changed dramatically in the last 15 years, and management of EOS has changed even more rapidly in the last five years.

METHODS

The Growing Spine Committee of the Scoliosis Research Society has embarked upon a review of the most current literature on EOS techniques and treatment.

RESULTS

This white paper provides recent updates on current techniques, including a summary of new modalities, indications, contraindications, and clinical results.

CONCLUSIONS

Although treatment of EOS is still challenging and complicated, the evolution of options and knowledge presents hope for better understanding and management in the future.

LEVEL OF EVIDENCE

Level V.

Experience with definitive instrumented final fusion after posterior-based distraction lengthening in patients with early-onset spinal deformity: single center results

Limited reports exist with regard to clinical and radiographic details of patients with early-onset spinal deformity (EOSD) undergoing definitive instrumented final fusion (FF) following implantation of a growing construct. Charts and radiographs were queried for all patients who underwent FF after management of EOSD with a distraction-based posterior construct at a single institution from 2006 to 2017. Patients managed during the growth modulation period with either proximal rib or spinal fixation were included. Thirteen patients qualified for inclusion. Spinal deformity etiologies were varied (neuromuscular: 5, idiopathic: 4, congenital: 4). Average age at implantation was 6.5 years, and patients underwent an average of 8.15 lengthening procedures over an average of 69 months. After the growing program, modest correction in main coronal Cobb was obtained at FF (average 52.4° before FF, 37.6° following FF, P<0.001; average percent improvement of 27%). Five patients required posterior column osteotomies. Using criteria proposed by Flynn and colleagues, 'minimal' coronal correction was achieved in 23% of patients and 'moderate' in 77%. No patient achieved 'substantial' (>50%) correction. Subjective poor bone quality was appreciated in 67% of patients, and 85% were noted to have areas of autofusion over previously spanned levels. Two (15%) patients sustained a total of four complications. After growth modulation procedures, EOSD deformities are generally stiff, bone quality is often subjectively poor, and autofusion is common, even after use of proximally rib-based systems. Modestly improved coronal Cobb correction can be obtained at FF but may require single or multiple posterior osteotomies. Intraoperative difficulties can be expected, and clinicians should be alert for intraoperative and postoperative complications.

Anterior Spinal Growth Tethering for Skeletally Immature Patients with Scoliosis: A Retrospective Look Two to Four Years Postoperatively

BACKGROUND

Anterior spinal growth tethering (ASGT) has been shown to alter spinal growth with the potential to correct scoliosis while maintaining spine flexibility. The purpose of this study was to report the 2 to 4-year outcomes of ASGT in skeletally immature patients with thoracic scoliosis.

METHODS

We conducted a retrospective review of patients with thoracic scoliosis who underwent ASGT with a minimum of 2 years of follow-up. Patient demographics, perioperative data, and radiographic outcomes are reported. A "successful" clinical outcome was defined as a residual curve of <35° and no posterior spinal fusion indicated or performed at latest follow-up.

RESULTS

Seventeen patients met the inclusion criteria. The etiology was idiopathic for 14 and syndromic for 3. The mean follow-up was 2.5 years (range, 2 to 4 years). Preoperatively, all patients were at Risser stage 0, with a mean age at surgery of 11 ± 2 years (range, 9 to 14 years). There was an average of 6.8 ± 0.5 vertebrae tethered per patient. The average thoracic curve magnitude was 52° ± 10° (range, 40° to 67°) preoperatively, 31° ± 10° immediately postoperatively, 24° ± 17° at 18 months postoperatively, and 27° ± 20° at latest follow-up (51% correction; range, 5% to 118%). Revision surgery was performed in 7 patients: 4 tether removals due to complete correction or overcorrection, 1 lumbar tether added, 1 tether replaced due to breakage, and 1 revised to a posterior spinal fusion. In 3 additional patients, posterior spinal fusion was indicated due to progression. Eight (47%) of the patients had a suspected broken tether. Ten (59%) of the 17 were considered clinically successful.

CONCLUSIONS

Despite most patients having some remaining skeletal growth at the time of review, the results of the current study demonstrate that at mid-term follow-up, ASGT showed a powerful, but variable, ability to modulate spinal growth and did so with little perioperative and early postoperative risk. Fusion was avoided for 13 of the 17 patients. The overall success rate was 59%, with a 41% revision rate. Understanding the parameters leading to success or failure will be critical in advancing a reliable definitive nonfusion treatment for progressive scoliosis in the future.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Sagittal plane parameters in growing rod patients following final fusion

Almost half of growing rod (GR) patients that undergo final fusion (FF) have an extension of instrumented levels. The purpose of this study was to review sagittal plane radiographic parameters of patients with distal extension of instrumented levels at FF to those whose levels remained the same. Radiographs were assessed preoperatively, after GR insertion/first lengthening, following GR treatment before FFs, and after FF. Measurements included sagittal balance, lumbar lordosis, thoracic kyphosis, and distal junction angle (DJA). Twenty-one patients were included. There was no change in sagittal balance. There was a significant decrease in lordosis and kyphosis following initial GR implantation. Kyphosis and lordosis increased during the GR period, but remained unchanged at time of FF. DJA increased 8° on average. Seven patients had distal extension of instrumented levels at time of FF (average 2 levels, range: 1-4). Indication for distal extension was sagittal plane decompensation in four cases. When comparing patients who had distal extension at the time of FF to those whose levels remained the same, there was no difference in the change in sagittal balance, lordosis, or kyphosis. Final DJA was significantly smaller in those patients with distal extension. Most GR patients that undergo FF demonstrate acceptable correction of sagittal plane radiographic parameters. A small cohort of patients requires distal extension at FF due to sagittal plane decompensation.

LEVEL OF EVIDENCE

Level IV, Therapeutic.

What's New in Congenital Scoliosis?

BACKGROUND

Congenital scoliosis is a failure of vertebral formation, segmentation, or a combination of the 2 arising from abnormal vertebral development during weeks 4 to 6 of gestation. The associated spinal deformity can be of varying severity and result in a stable or progressive deformity based on the type and location of the anomalous vertebra(e). Bracing for congenital scoliosis is rarely indicated, while recent reports have demonstrated the utility of serial derotational casting for longer curves with multiple anomalous vertebrae as an effective "time buying strategy" to delay the need for surgery. Earlier hemivertebra excision and short-segment posterior spinal fusion have been advocated to prevent future curve progression of the deformity and/or the development of large compensatory curves. It has been shown in recent long-term follow-up studies that growth rates of the vertebral body and spinal canal are not as dramatically affected by pedicle screw instrumentation at a young age as once thought. Growth friendly surgery with either spine-based or rib-based anchors has demonstrated good results with curve correction while maintaining spinal growth. Rib-based anchors are typically more commonly indicated in the setting of chest wall abnormalities and/or when spinal anatomy precludes placement of spinal instrumentation. Recently, magnetically controlled growing rods have shown promising results in several studies that include a small subset of congenital scoliosis cases.

METHODS

A literature search was performed to identify existing studies related to the treatment of congenital scoliosis published from January 1, 2005 to June 1, 2016. Databases included PubMed, Medline, and the Cochrane Library. The search was limited to English articles and yielded 36 papers. This project was initiated by the Pediatric Orthopaedic Society of North America Publications Committee and was reviewed and approved by the Pediatric Orthopaedic Society of North America Presidential Line.

RESULTS

A total of 36 papers were selected for review based upon new findings. Classic manuscripts on congenital scoliosis are also included to provide sufficient background information.

CONCLUSIONS

Congenital scoliosis represents a wide range of pathology from the simple, stable hemivertebra to the complex, progressive spinal deformity with chest wall abnormalities and associated cardiac, renal, and neural axis anomalies. This paper reviews the natural history and associated anomalies with congenital scoliosis as well as the most up-to-date classification schemes and various treatment options for the care of this challenging patient population.

LEVEL OF EVIDENCE

Level 5.

Evolution of the postoperative sagittal spinal profile in early-onset scoliosis: is there a difference between rib-based and spine-based growth-friendly instrumentation?

OBJECTIVE Although the vertical expandable prosthetic titanium rib (VEPTR) and growing rod instrumentation (GRI) encourage spinal growth via regular lengthening, they can create different results because of their different fixation patterns and mechanisms in correcting scoliosis. Previous studies have focused comparisons on coronal plane deformity with minimal attention to the sagittal profile. In this retrospective study, the authors aimed to compare the evolution of the sagittal spinal profile in early-onset scoliosis (EOS) treated with VEPTR versus GRI. METHODS The data for 11 patients with VEPTR and 22 with GRI were reviewed. All patients had more than 2 years' follow-up with more than 2 lengthening procedures. Radiographic measurements were performed before and after the index surgery and at the latest follow-up. The complications in both groups were recorded. RESULTS Patients in both groups had similar diagnoses, age at the index surgery, and number of lengthening procedures. The changes in the major coronal Cobb angle and T1-S1 spinal height were not significantly different between the 2 groups. Compared with the GRI group, the VEPTR group had less correction in thoracic kyphosis (23% ± 12% vs 44% ± 16%, p < 0.001) after the index surgery and experienced a greater correction loss in thoracic kyphosis (46% ± 18% vs 11% ± 8%, p < 0.001) at the latest follow-up. Although the increase in the proximal junctional angle was not significantly different (VEPTR: 7° ± 4° vs GRI: 8° ± 5°, p = 0.569), the incidence of proximal junctional kyphosis was relatively lower in the VEPTR group (VEPTR: 18.2% vs GRI: 22.7%). No significant changes in the spinopelvic parameters were observed, while the sagittal vertical axis showed a tendency toward a neutral position in both groups. The overall complication rate was higher in the VEPTR group than in the GRI group (72.7% vs 54.5%). CONCLUSIONS The VEPTR had coronal correction and spinal growth results similar to those with GRI. In the sagittal plane, however, the VEPTR was not comparable to the GRI in controlling thoracic kyphosis. Thus, for hyperkyphotic EOS patients, GRI is recommended over VEPTR.

The Crankshaft Phenomenon

The crankshaft phenomenon, a progressive rotational and angular spinal deformity that can occur after posterior spinal surgery, has been reported in pediatric patients with idiopathic, congenital, and neuromuscular scoliosis. In the skeletally immature patient, the crankshaft phenomenon is thought to occur secondary to continued growth of the anterior elements of the spine after solid posterior spinal fusion. The condition has also been reported in the setting of newer, so-called growth-friendly posterior distraction-based spinal instrumentation. The clinical evidence of crankshaft phenomenon is often subtle, whereas radiographic findings are usually more apparent. However, objective measurement of radiographic signs may be complicated by instrumentation and postoperative changes. Treatment options for patients with the crankshaft phenomenon are limited; in those with problematic deformity and/or risk of progression, additional surgery may be indicated.

Magnetic Resonance Imaging Safety of Magnetically Controlled Growing Rods in an In Vivo Animal Model

STUDY DESIGN

Experimental animal study.

OBJECTIVE

To investigate the interaction between magnetically controlled growing rods (MCGRs) and magnetic resonance imaging (MRI).

SUMMARY OF BACKGROUND DATA

Growing rod treatment through serial operations results in adverse effects on the patient and high treatment costs. MCGRs can be lengthened noninvasively in an outpatient setting and with lower treatment costs. When MRI investigation is required, the interaction between MCGRs and MRI is an issue of concern in patients with MCGRs. This study investigated MRI compatibility of MCGRs in an in vivo setting.

METHODS

The study was conducted on three sheep. A standard posterior approach was used. One polyaxial pedicle screw at the ends was placed. Two sheep were instrumented unilaterally and one bilaterally with MCGRs. Temperature change was measured using MR-compatible sensors. Thoracic and lumbar MRIs were obtained using a 0.3 T MRI unit. MRI waves were applied for 45 minutes and temperature changes were recorded every 3 minutes. The lengths of the MCGRs were measured and anteroposterior and lateral spine radiographs were obtained pre- and postoperatively.

RESULTS

No displacement in the positions of the MCGRs occurred. The lengths of the MCGRs did not change compared with the preoperative length. The ability of the MCGRs to elongate was not impaired after MRI scanning. There was a mean increase in the temperature of the MCGRs by 1.45°C (0.5-2.4°C). The MCGRs had a strong scattering effect on MRI of the related segments.

CONCLUSION

This study indicated that lower magnet MRI is safe in an animal model with MCGRs, with no displacement of the rods and no changes in their length, no significant heating, and no adverse effects on the lengthening mechanism but with a significant scattering effect on visualization of the surrounding tissues. Further investigations are needed to clarify the exact distance where an MRI investigation of distant organs may be done without scattering.

LEVEL OF EVIDENCE

N/A.

Biomechanical Evaluation of a Growth-Friendly Rod Construct

BACKGROUND

Distraction-type rods mechanically stabilize the thorax and improve lung growth and function by applying distraction forces at the rib, spine, pelvis, or a combination of locations. However, the amount of stability the rods provide and the amount the thorax needs is unknown.

METHODS

Five freshly frozen and thawed cadaveric thoracic spine specimens were tested for lateral bending, flexion/extension, and axial rotation in displacement control (1°/sec) to a load limit of ±5 Nm for five cycles after which a growth-friendly unilateral rod was placed in a simulated rib-to-lumbar attachment along the right side. The specimens were tested again in the same modes of bending. From the seven Optotrak Orthopedic Research Pin markers (Northern Digital Inc., Waterloo, Ontario, Canada) inserted into the top potting to denote T1, and the right pedicles at T2, T4, T5, T8, T9, and T11 and the Standard Needle Tip Pressure Transducers (Gaeltech, Isle of Skye, Scotland) inserted into the T4/T5 and T8/T9 discs, motion, stiffness, and pressure data were calculated. Parameters from the third cycle of the intact case and the construct case were compared using two-tailed paired t tests with 0.05 as the level of significance.

RESULTS

With the construct attached, the T1-T4 segment showed a 30% increase in neutral zone stiffness during extension (p = .001); the T8-T12 segment experienced a 63% reduction in the in-plane range of motion during flexion (p = .04); and the T8/T9 spinal motion unit had a significant decrease of 24% in elastic zone stiffness during left axial rotation (p = .04).

CONCLUSIONS

It is clear the device as tested here does not produce large biomechanical changes, but the balance between providing desired changes while preventing complications remains difficult.

VEPTR Implantation After Age 3 is Associated With Similar Radiographic Outcomes With Fewer Complications

BACKGROUND

The purpose of this study was to analyze the risks and benefits of early vertical expandable prosthetic titanium rib (VEPTR) implantation (below 3 y of age) compared with delayed intervention (3 to 6 y of age). Early intervention with milder deformity may make device implantation easier and may facilitate symmetric chest and pulmonary development. However, later intervention may decrease the number of lengthenings required, and implant anchor points and bone quality may be better in older patients.

METHODS

A multicenter prospective database of patients treated with the VEPTR device was retrospectively reviewed. A total of 71 patients with minimum 5-year follow-up were included. Thirty-seven patients had VEPTR surgery below 3 years of age (group 1), and 34 patients had surgery between 3 and 6 years of age (group 2). Radiographs from the preoperative, immediate postoperative, and most recent follow-up visits were reviewed to determine coronal plane deformity and change in T1-T12 height over time. Complications were analyzed using a nonparametric mean cumulative function for the number of complications per subject over time.

RESULTS

Patients in both groups had similar diagnoses, ASA scores (P=0.22), and number of lengthenings (10±4 in both groups, P=0.40). Preoperative and most recent major Cobb angles were not significantly different between the 2 groups [66±22 and 60±20 degrees (group 1) vs. 63±19 and 57±23 degrees (group 2), respectively] (P=0.38). The change in T1-T12 was significantly correlated with the number of lengthenings (P<0.001); however, there was no difference between age groups (P=0.55). There were 118 complications in 33 subjects in group 1 and there were 69 complications in 28 subjects in group 2. The number of complications per lengthening was significantly different between the 2 age groups (P<0.001). Subjects in group 2 had 41% fewer complications per lengthening compared with subjects in group 1 (P<0.001).

CONCLUSIONS

VEPTR treatment resulted in similar deformity control and thoracic growth in both age groups with lower complication rates in the older population. The rate of complications was similar between the 2 groups for the first 2 years postimplantation, but after 2 years, the rate of complications increased over time faster for the younger group compared with the older group.

LEVEL OF EVIDENCE

Level III-retrospective chart and radiographic review.

Convex Instrumented Hemiepiphysiodesis With Concave Distraction: A Treatment Option for Long Sweeping Congenital Curves

BACKGROUND

Convex hemiepiphysiodesis has been reported to have mixed results in the treatment of congenital spine deformities. Multiple modifications of the original technique were suggested to improve the results. The purpose of this study is to report the results and complications of an instrumented convex growth arrest procedure modified with concave distraction.

METHODS

The records of 11 patients with long sweeping congenital curves (involving multiple anomalous vertebrae) who underwent convex instrumented hemiepiphysiodesis with concave distraction were evaluated. Mean age at index operation was 58 months (range, 29 to 101 mo). Lengthening of the concave distraction rod was done every 6 months. The magnitude of coronal/sagittal deformity and T1-T12 height were measured on the preoperative, postoperative, and latest follow-up radiographs. Average follow-up was 44.9 months (range, 24 to 89 mo).

RESULTS

In the coronal plane, the convex hemiepiphysiodesis segment was corrected from an average of 60.5 to 40.4 degrees postoperatively and further improved to 35.5 degrees at the latest follow-up. The distracted segment was corrected from 33.4 to 15.2 degrees postoperatively and to 12.7 degrees at the latest follow-up. Sagittal plane alignment was minimally affected. The average T1-T12 height was 157.1 mm in the early postoperative period and 181.1 mm at last follow-up. During follow-up, we identified partial pull-out of screws on the distraction side in 5 of the 11 patients and rod breakages in 3 patients. These were revised during planned lengthenings. There were no unplanned surgeries, deep wound infections, nor neurological complications.

CONCLUSIONS

Convex instrumented hemiepiphysiodesis with concave distraction resulted in good curve correction while maintaining the growth of thorax. The correction of the anomalous segment improved over time, proving the effectiveness of the hemiepiphysiodesis. Addition of a concave distraction construct appears to enhance spinal growth, thereby augmenting the hemiepiphysiodesis effect.

Fetal diagnosis of spondylocostal dysplasia: Limits of conventional fetal ultrasound & MRI in diagnosing anomalies

We present a case of postnatally recognized spondylocostal dysplasia that was prenatally misdiagnosed as fetal thoracolumbar kyphoscoliosis secondary to spinal fusion anomalies. Neither two-dimensional ultrasound nor MRI identified the rib anomalies, nor did they allow for correct identification of the more compromised lung. Spondylocostal and spondylothoracic dysostoses involve rib deformities and distortion of the bony thorax that lead to pulmonary compromise. Correct prenatal diagnosis might not be made with standard fetal imaging. Three-dimensional ultrasound should be pursued (when available) upon recognition of a thoracic scoliosis to fully assess rib development.

Self-growing Instrumentation With Gliding Connectors for Collapsing Spine Deformities in Children: A Novel Technique

BACKGROUND

The optimal management of young children with neuromuscular spinal deformities is currently unknown. A number of spinal instrumentation techniques have been proposed in early-onset scoliosis to achieve "guided growth," each with its drawbacks.

OBJECTIVE

To report a novel self-growing spinal instrumentation technique, designed to avoid recurrent surgeries in children with neuromuscular disease.

METHODS

The technique is based on the control of apical and end vertebrae by pedicle screw fixation and limited fusion. Standard 4.5 to 5.5 mm side-to-side rod connectors are used as gliding connections. Three children with neuromuscular disease underwent the described procedure. The patients were followed for an average of 36 months (range, 24 to 60 mo).

RESULTS

All patients who underwent the procedure showed an average spinal growth of 1.1 mm/year, which is comparable with normative growth data and previous reports using growing rods. One patient required the exchange of dislodged rods, secondary to the amount of growth of the spine. There were no other complications or unplanned surgeries during the follow-up period.

CONCLUSIONS

This novel method provided growth in a group of 3 patients with collapsing neuromuscular spine deformities.

LEVEL OF EVIDENCE

Level IV-case series.

The effect of serial growing rod lengthening on the sagittal profile and pelvic parameters in early-onset scoliosis

STUDY DESIGN

Retrospective case series.

OBJECTIVE

To report the effect of repeated growing rod (GR) lengthenings on the sagittal and pelvic profile in patients with early-onset scoliosis.

SUMMARY OF BACKGROUND DATA

Posterior distraction-based GRs have gained popularity as a technique for the surgical management of early-onset scoliosis. However, there are no published studies on the effect of serial GR lengthenings on sagittal balance, thoracic kyphosis (TK), lumbar lordosis (LL), and pelvic parameters.

METHODS

We retrospectively reviewed data from a multicenter early-onset scoliosis database. Forty-three patients who were able to walk with minimum 2-year follow-up who underwent single- or dual-GR surgery were included for review. Mean number of lengthenings was 6.4 (range, 3-16). Mean preoperative age was 5.6 years (standard deviation, 2.4 yr), and mean follow-up was 3.5 years. Maximum TK, LL, and sagittal balance were assessed preoperatively, after index surgery, and at the latest follow-up.

RESULTS

There was a significant decrease both in TK and LL after index surgery, which then increased during the lengthening period. There was a significant increase in both proximal junctional kyphosis and distal junctional angle. Pelvic parameters (pelvic tilt, pelvic incidence, sacral slope) were unchanged during the treatment period. Significant improvement was observed in sagittal balance. There was a correlation between the change in TK and change in LL.

CONCLUSION

TK decreased after index surgery and increased between the index surgery and the latest follow-up, which was accompanied by an increase in LL. All-screw proximal constructs had mean 9° more proximal junctional kyphosis than all-hook proximal constructs. An increase in proximal junctional kyphosis and distal junctional angle was found during the treatment period. Although there was an independent effect of number of lengthenings on TK, there was no significant detrimental effect on other sagittal spinopelvic parameters. GRs had a positive effect on sagittal vertical axis, which returned patients to a more neutral alignment through the course of treatment.

LEVEL OF EVIDENCE

4.

Comparison of osteotomy versus non-osteotomy approach for congenital scoliosis: a retrospective study of three surgical techniques

Background

Currently, there are many reports about congenital scoliosis (CS) treatment, but there are still controversies existing with respect to selecting its surgical methods.

Methods

Retrospective analyses were conducted on 31 CS patients. The surgical treatments included the following: posterior instrumentation (10 patients; group 1), pedicle subtraction osteotomy (11 patients; group 2) and vertebral column resection (10 patients; group 3).

Results

All patients had remarkable improvements in morphology, image findings, visual analogue scale and American Spinal Injury Association classification. Groups 2 and 3 had greater preoperative sagittal Cobb's angle (25.0, 62.2 and 9.2°, respectively), greater intra-operative blood loss (604.5, 620.0 and 460.0 mL, respectively) and fewer fused segments (5.8, 6.3 and 9.2, respectively) than group 1. As compared with group 1, groups 2 and 3 had greater correction rate of coronal Cobb's angle (79.6 ± 12.8, 78.2 ± 10.1% versus 56.1 ± 11.1%), and coronal trunk inclination (77.6 ± 14.2, 85.2 ± 11.0% versus 45.0 ± 42.5%). The sagittal Cobb's angle correction rates of three groups were 67.7 ± 42.9, 79.3 ± 27.6, 84.3 ± 12.1%, respectively, which showed no significant difference (P = 0.461). With an average follow-up of 3.5, 3.2 and 4.0 years, the correction loss rate of coronal Cobb's angle in group 1 was higher than those of groups 2 and 3.

Conclusion

For CS patients, osteotomy procedure had less fused segments, along with a greater correction rate and lower correction loss, which were more advantageous for those with severe deformity in sagittal plane or nerve decompression requirements.

Recent advances in the management of early onset scoliosis

As the undesired results of early spinal fusion have become apparent, "growth-friendly" management methods for early onset scoliosis have been increasing during recent years. Current literature supports the use of repeated corrective cast applications as the initial management for most early onset progressive spinal deformities as either definitive treatment or as a temporizing measure. If casting is not an option or the deformity cannot be controlled via casting, one of the growth-friendly instrumentation techniques is chosen. Growth-friendly surgical methods and implants have been evolving as understanding of the disease improves.

Feasibility of correction with instrumentation only in congenital scoliosis

BACKGROUND

Although effective correction of deformity in congenital scoliosis can often be achieved with instrumentation only and without more invasive techniques such as hemivertebrectomy (HV), reports of the feasibility of correction with instrumentation only (IO) are lacking.

OBJECTIVE

To compare the results of deformity correction using IO vs HV and to examine the feasibility of and indications for correction with IO in patients with congenital scoliosis.

METHODS

Twenty-five patients underwent correction with either IO (n = 14) or HV (n = 11). The 2 patient groups were compared in terms of age at the time of surgery, preoperative magnitude and flexibility of the main curve, correction rates after surgery and at the final follow-up, surgery time, estimated blood loss, and complications.

RESULTS

The 2 groups did not differ significantly in terms of average patient age or curve magnitude, but the correction with the IO group had greater preoperative curve flexibility (37.1%) than the HV group (21.0%). The correction rates immediately after surgery were high in both groups. The correction with IO group had a shorter mean operation time (308 minutes vs 366 minutes) and less blood loss (540 mL vs 1547 mL) than the HV group.

CONCLUSION

Satisfactory correction of congenital scoliosis can be obtained with IO if there is adequate flexibility in the main curve, thus avoiding the need for more invasive procedures such as HV.

Treatment of congenital thoracic scoliosis with associated rib fusions using VEPTR expansion thoracostomy: a surgical technique

INTRODUCTION

Untreated growing patients with congenital scoliosis and fused ribs will develop finally thoracic insufficiency syndrome. The technique of expansion thoracoplasty with implantation of a vertical expandable prosthetic titanium rib (VEPTR) was introduced initially to treat these children.

METHODS

This article attempts to provide an overview of the surgical technique of opening-wedge thoracostomy and VEPTR instrumentation in children with congenital thoracic scoliosis and fused ribs.

RESULTS

Our modification of the surgical approach using a posterior midline incision rather than the modified thoracotomy incision initially described could potentially help to diminish wound dehiscence and secondary infection, while preserving a more acceptable esthetic appearance of the back.

CONCLUSIONS

Vertical expandable prosthetic titanium rib-based treatments should be undertaken only with a good knowledge of its numerous specific complications. Every aspect of the treatment should be oriented to minimize these complications. At the same time it should be kept in mind that the ultimate step of this long-term fusionless treatment strategy will be a technically demanding spine fusion.

Effects of the fusionless instrumentation on the disks and facet joints of the unfused segments: a pig model

BACKGROUND

Growing rod (GR) is a state-of-the-art procedure favored when curvatures of the spine cannot be managed nonoperatively in early-onset scoliosis. Although some postulate that multiple distractions and/or relative immobilization of the unfused segments affect the health of disk and facet joint (FJ) and cause degeneration and/or spontaneous fusion, this has not thoroughly been investigated. In this study, changes in the unfused segment after a spine-based fusionless instrumentation (SBFI) are investigated and compared with the control (CG) and instrumented fusion (IF) groups.

METHODS

A total of 13 piglets, 10 to 14 weeks of age, were used. SBFI and IF were performed on 7 and 3 piglets, respectively, and 3 formed the CG. In SBFI, lengthening procedures of 5 mm were applied once monthly for 3 months, and, after 4 months, all piglets were euthanized. Histologic sections of the unfused disks and FJ were analyzed, and morphometric histologic analysis was performed.

RESULTS

On the basis of the Gries criteria, unfused disk median grades were 1, 2, and 4 for control, SBFI, and IF, respectively, that revealed a statistical difference (P<0.001). Unfused FJ median grades were 1 and 2 for control and SBFI, respectively, that revealed a statistical difference (P<0.001). The mean hypertrophic zone (HZ) heights were 69.78, 84.20, and 66.14 μm; HZ chondrocyte cell widths were 19.03, 18.76, and 17.36 μm; and HZ chondrocyte cell heights were 15.01, 15.04, and 12.42 μm in the CG, SBFI, and IF groups, respectively. Statistically, for HZ heights, SBFI was different compared with CG and IF (P<0.001), and, for HZ chondrocyte cell widths and heights, IF was different compared with CG and SBFI (P<0.001).

CONCLUSIONS

Morphometric analysis in this study supports the findings that SBFI preserves the growth potential of the spine. Furthermore, changes in the HZ heights show that distractive forces stimulate the apophyseal growth of the axial skeleton describing how the growth rate of the spine in GR might surpass the normal growth rate. Overall, although some degenerative changes are observed, SBFI and repeated distractions alone are not solely responsible for FJ arthrosis and disk degeneration, given that they are structurally preserved.

CLINICAL RELEVANCE

GR and regular lengthening procedures do not impair disk health and preserve the growth potential of the spine if it is applied with a meticulous technique.

[Early onset scoliosis. What are the options?]

The prognosis of children with progressive early onset scoliosis has improved considerably due to recent advances in surgical and non-surgical techniques and the understanding of the importance of preserving the thoracic space. Improvements in existing techniques and development of new methods have considerably improved the management of this condition. Derotational casting can be considered in children with documented progression of a <60° curve without previous surgical treatment. Both single and dual growing rods are effective, but the latter seem to offer better results. Hybrid constructs may be a better option in children who require a low-profile proximal anchor. The vertical expandable prosthetic titanium rib (VEPTR(®)) appears to be beneficial for patients with congenital scoliosis and fused ribs, and thoracic Insufficiency Syndrome. Children with medical comorbidities who may not tolerate repeated lengthenings should be considered for Shilla or Luque Trolley technique. Growth modulation using shape memory alloy staples or other tethers seem promising for mild curves, although more research is required to define their precise indications.

Ossifications after vertical expandable prosthetic titanium rib treatment in children with thoracic insufficiency syndrome and scoliosis

STUDY DESIGN

Retrospective analysis of 1328 spinal radiographs of 57 patients after vertical expandable prosthetic titanium rib (VEPTR) implantation with an average follow-up of 30 months.

OBJECTIVE

To evaluate the incidence, time of onset, as well as the underlying factors influencing the occurrence of ossifications in children treated with VEPTR.

SUMMARY OF BACKGROUND DATA

Spontaneous spinal fusions and ossifications are well known in children treated with spinal implants. In theory, children with spinal deformity and VEPTR implantation are less likely to develop these complications because of either little or no implant contact to the spine.

METHODS

Fifty-seven patients had a primary VEPTR implantation due to spinal deformity and thoracic insufficiency syndrome and repeated lengthening procedures. The mean age at the time of primary surgery was 7.7 years, the mean duration of follow-up was 29.8 months, and the mean number of operations was 5.9. A total of 1328 spinal radiographs were analyzed with respect to the occurrence and growth of ossifications, implant migration, and other complications.

RESULTS

Overall, 24% of the patients (n = 13) had ossifications, which affected in 92% the main load sharing VEPTR implant. The fusions involved in 54% of cases the lumbar spine and in each 23% the ribs and the iliac crest. Ossifications developed in 11% of children within the first year of treatment and increased by about the same rate per annum. After 53 months, 48% of the radiographs showed some ossifications. There was a significant correlation to the stiffness of the deformity and the number of surgical procedures.

CONCLUSION

Contrary to previous assumptions, it was shown that in children treated with the VEPTR system, 48% of children showed ossifications after 53 months. Ossifications were observed significantly more often in children with stiff deformities and after multiple surgical procedures. It is a much more common problem than previously thought.

LEVEL OF EVIDENCE

3.

Non-fusion and growing instrumentation in the correction of congenital spinal deformity associated with split spinal cord malformation: an early follow-up outcome

STUDY DESIGN

A retrospective case review.

INTRODUCTION

To evaluate the safety and efficacy of the non-fusion technique in achieving and maintaining the proper correction for congenital spinal deformity (CSD) and allowing normal spinal growth in patients with split spinal cord malformation (SSCM).

MATERIALS AND METHODS

Seven patients who had CSD and SSCM were adopted, with a mean age of 8 years. All the patients in this study received Halo-gravity traction (HGT) prior to expansion of the spine and instrumentation with vertical expandable titanium prosthetic rib, growing rod or their hybrid. Five of them underwent opening wedge thoracoplasty simultaneously. And the two patients with type I SSCM underwent bony spur excision in the initial surgery before corrective manipulation. Then all the patients received a lengthened operation every six months. Changes of their major curve and length of T1-S1 spine were measured, and complications, neurological status were recorded. All the patients were followed up with an average of 32.6 months.

RESULTS

Their mean major curve improved from 90.1° to 58.6° with a correction rate of 34.9 %. The T1-S1 length increased from 26.3 to 34.7 cm at final follow-up. Especially, one of the type I SSCM patients whose neurological deterioration was found preoperatively was significantly improved.

CONCLUSION

Preoperative Halo-gravity traction followed by non-fusion and growing instrumentation may be effective and safe for young children of CSD associated with SSCM. But it is an ongoing study and additional large multicenter studies are necessary to further assess the safety and efficacy of non-fusion and growing instrumentation.

Growing rods for the treatment of scoliosis in children with cerebral palsy: a critical assessment

STUDY DESIGN

Retrospective analysis.

OBJECTIVE

To evaluate, in children with cerebral palsy, the following aspects of growing rod (GR) treatment for scoliosis: structural effectiveness, effect of pelvic fixation, hospital stay duration, and complications.

SUMMARY OF BACKGROUND DATA

Children with cerebral palsy frequently develop severe spinal deformity and pelvic obliquity (PO). Growth-preserving strategies are attractive, but comorbidities raise the risk/benefit ratio. To our knowledge, no previous studies have focused on growth-preserving spine surgery in these children.

METHODS

From our multicenter patient group, we identified 27 children with cerebral palsy treated with GRs (single rod in 4; dual rods in 23 [15 extending to the pelvis]). We collected radiographical, surgical, hospital stay, and major complication data. We compared Cobb angle and PO improvement between patients with and without pelvic instrumentation via the Student t test (significance, P = 0.05). No patient required anterior spinal fusion.

RESULTS

Average improvements for all patients (preoperative to latest follow-up) were: Cobb angle, 35° ± 23°; PO, 14° ± 19°; T1-S1 length, 7.9 ± 4.4 cm; and space available for lung ratio, 0.17 ± 0.21. For the 8 patients who underwent fusion, average improvements (preoperative to postfusion) were: Cobb angle, 43° ± 28°; PO, 2° ± 21°; T1-S1 length, 9.5 ± 6.0 cm; and space available for lung ratio, 0.26 ± 0.28. Pelvic GR fixation produced better PO correction (P < 0.001) but similar Cobb angle correction (P = 0.556). Hospital stays averaged 8.7 ± 12.1 days after initial surgery, 1.4 ± 2.5 days after lengthening (45% were outpatient procedures), and 13.4 ± 6.2 days after fusion. The most common complication was deep wound infection (30%).

CONCLUSION

GRs via a posterior-only approach are effective. Constructs extending to the pelvis control PO more effectively. However, 30% of patients experienced deep wound infection.

Convex instrumented hemiepiphysiodesis with concave distraction: a preliminary report

BACKGROUND

The convex growth arrest (CGA) procedure has been well accepted for treatment of congenital scoliosis as it is a simpler procedure with successful results. However, unpredictability of curve behavior, slow and usually inadequate correction, and necessity of anterior surgery for completeness of the epiphysiodesis are its shortcomings.

QUESTIONS/PURPOSES

In a preliminary study we asked whether a modification of the CGA procedure using convex instrumented hemiepiphysiodesis with concave distraction would correct the coronal plane Cobb angles and would correct or maintain sagittal plane local and global kyphosis angles. We also identified complications.

PATIENTS AND METHODS

We retrospectively reviewed five female patients who underwent the modified procedure. Their mean age at the index operation was 40 months (range, 17-55 months). The patients underwent concave distractions every 6 months. The magnitude of the convex instrumented and concave distracted curves and sagittal plane parameters were determined on the preoperative and most recent followup radiographs. Minimum followup was 26 months (mean, 34 months; range, 26-40 months).

RESULTS

In the coronal plane, the preoperative magnitude of the convex instrumented congenital curve averaged 48°. It was corrected to 36° (25%) postoperatively and was further improved to 27° (44%) at the latest followup. For the distracted segment, the mean preoperative curve was 35°, corrected to 16° postoperatively and to 8° at the latest followup, for an average correction of 77%. Sagittal plane alignment was minimally affected from the procedure. In four of the five patients we identified partial pullout of screws for the concave distraction; these were revised at the time of planned lengthening.

CONCLUSIONS

This procedure may obviate the need for multiple osteotomies and long thoracic fusions in young children with long sweeping thoracic deformities involving multiple anomalous vertebrae. Implant-related complications on the concave side may be avoided using paired pedicle screws at the proximal and distal anchor sites.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the guidelines online for a complete description of level of evidence.

Chest wall repair in Poland syndrome: complex single-stage surgery including Vertical Expandable Prosthetic Titanium Rib stabilization--a case report

Various surgical techniques have been described for repair of chest wall defects in Poland syndrome. We describe the case of a 16-year-old boy who underwent autologous rib transposition after sternal osteotomy. Chest wall stabilization was achieved using a combination of K-wires and Vertical Expandable Prosthetic Titanium Rib (Synthes GmbH, Freiburg, Germany). Reconstruction of the soft tissue defect was accomplished by combined latissimus dorsi muscle flap and Permacol patch (Covidien Deutschland GmbH, Neustadt, Germany). This approach might be considered an effective 1-stage treatment option of this condition in postpubescent boys.

Congenital kypho-scoliosis: a case of thoracic insufficiency syndrome and the limitations of treatment

INTRODUCTION

Congenital spinal vertebral anomalies may present with deformity resulting in congenital scoliosis and kyphosis. This leads to abnormal spinal growth. The latter when combined with associated rib fusions may impair normal thoracic cage development and resultant pulmonary hypoplasia. Most congenital scoliosis can be detected in utero by ultrasound scan or recognized in the neonatal period, but a few spinal defects can remain undetected.

MATERIALS AND METHODS

In this Grand Round, we present the case of a 7-year-old girl with a severe scoliosis and thoracic insufficiency syndrome (TIS). 3D CT reconstruction imaging demonstrated a mixed picture of fusion and segmentation abnormalities. A marked kyphoscoliosis was demonstrated at the thoraco-lumbar junction. Via a left thoracotomy, anterior excision of intervertebral discs was performed together with, interbody fusion, and in situ stabilisation of the kyphosis with double allograft (femur) strut grafts.

CONCLUSIONS

This article highlights the features of congenital kypho-scoliosis and TIS. The difficulties of treating kyphosis when combined with TIS are discussed together with the limitations of current surgical techniques.

Early definitive spinal fusion in young children: what we have learned

BACKGROUND

Early-onset scoliosis, when left untreated, leads to severe deformity. Until the last decade, treatment of progressive curves in young children often consisted of definitive spinal fusion. The recognition of thoracic insufficiency syndrome associated with definitive early fusion has led to the development of new surgical techniques developed to preserve spinal and thoracic growth in young patients with progressive scoliosis.

QUESTIONS/PURPOSES

We asked: (1) Does early definitive fusion arrest progression of spinal deformity? To what extent does early definitive spinal fusion influence (2) pulmonary function and (3) thoracic growth?

METHODS

A Medline search of the published literature on early-onset scoliosis, congenital scoliosis, and infantile scoliosis between 2008 and 2010 was performed on spinal fusion for early-onset scoliosis, focusing on studies reporting pulmonary function at followup.

RESULTS

Spinal deformity is apparently not well controlled by early fusion since revision surgery has been required in 24% to 39% of patients who underwent presumed definitive fusion in early childhood. Restrictive pulmonary disease, defined as forced vital capacity less than 50% of normal, occurs in 43% to 64% of patients who undergo early fusion surgery with those children who have extensive thoracic fusions and whose fusions involve the proximal thoracic spine at highest risk. Thoracic growth after early surgery is an average of 50% of that seen in children with scoliosis who do not have early surgery. Diminished thoracic spinal height correlates with decreased forced vital capacity.

CONCLUSIONS

The literature does not support routine definitive fusion of thoracic spinal deformity at an early age in children with scoliosis.

Posterior unilateral pedicle subtraction osteotomy of hemivertebra for correction of the adolescent congenital spinal deformity

BACKGROUND CONTEXT

The treatment of adolescent congenital deformity (late-diagnosed congenital deformity) is still unknown. The best candidates for hemivertebra excision are young patients, typically between 4 and 6 years of age. Partial excision may be feasible for older children.

PURPOSE

The purpose of this study was to assess the effect of unilateral pedicle subtraction osteotomy of hemivertebra for correction of the adolescent congenital spinal deformity.

STUDY DESIGN

Retrospective analysis.

PATIENT SAMPLE

Twelve patients with adolescent congenital deformity who underwent posterior unilateral pedicle subtraction osteotomy and correction were evaluated. Mean age at the time of surgery was 17 years.

OUTCOME MEASURES

The charts, standing full-length posteroanterior and lateral view radiographs, and functional measures were reviewed.

METHODS

For evaluation of surgical effectiveness, comparative analysis of the parameters of the total main curve, the segmental curve, the compensatory cranial and caudal curves, the segmental kyphosis, and the trunk shift before and after operation and at the most recent follow-up was done.

RESULTS

The mean follow-up period was 40.5 months. Mean Cobb angles of the total main curve and the segmental curve were, respectively, 47.5° and 43.8° before surgery, 23.7° and 16.5° after surgery, and 22.6° and 17° at the last follow-up. The angle of segmental kyphosis was 11.8° before surgery, 6.2° after surgery, and 7.8° (range, -30° to 26°) at the final follow-up. The mean final global lordosis was within the normal range. No neurologic deficit occurred. Solid fusion was achieved for all cases.

CONCLUSIONS

Unilateral pedicle subtraction osteotomy with instrumentation from a posterior-only approach is indicated in older teenagers for an adolescent congenital spinal deformity. Compared with hemivertebra excision, corrective surgery with hemivertebra osteotomy has a lower intraoperative blood loss and shorter operation time.