Comparison of combined anterior–posterior and posterior-only approaches for lumbosacral chordomas: a systematic review and meta-analysis of surgical and clinical outcomes

Lumbosacral chordoma is a slow-growing but locally aggressive tumor, resistant to adjuvant treatments and endowed with dismal prognosis. Surgery is the mainstay of treatment but the choice of surgical approach (the posterior-only approach or the combined anterior–posterior approach) remains an open question due to the need of both pursuing a surgical radicality and preserving the neurologic function. The aim of the study was to compare the surgical and clinical outcomes of these approaches in the management of lumbosacral chordomas. A systematic review and meta-analysis in agreement with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines of papers comparing the outcomes of the two approaches was performed. Ten papers met the inclusion criteria. The combined anterior–posterior approach was more frequently performed for tumors with an upper level beyond S2 (p?=?0.012). The 5-year progression-free survival was significantly higher in posterior-only approach compared with the combined anterior–posterior approach (44.7% vs 27.1%, p?=?0.049). Adjuvant radiotherapy was added more frequently after a posterior-only approach (p?=?0.036) and the rate of complications was significantly lower after a posterior-only approach (p?=?0.040). No significant differences in sex, age, tumor diameter, entity of resection, and overall survival were observed. Posterior-only surgical approach may be a reasonable option for lumbosacral chordoma, being associated with comparable entity of surgical resection, reduced complication rate and increased 5-year progression-free survival rate as compared with combined anterior–posterior approach.

     

One-step (standard) versus two-step surgical approach in adolescent idiopathic scoliosis posterior spinal fusion: Which is better?

Study design

A retrospective cohort study with IRB approval.

Introduction

Significant blood loss remains an important concern in terms of the performance of the posterior spinal fusion in adolescent idiopathic scoliosis. Several strategies have been reported to minimize blood loss during surgery. In order to address the need to minimize blood loss without sacrificing the quality of the fusion, in our hospital, we adopted a two-step surgical approach. This surgical approach consist of the exposure and instrumentation of the lumbar region prior to and followed by an extension of the surgical incision to the thoracic region for its subsequent instrumentation. The main purpose of this study was to compare a two-step surgical approach with the one-step (standard) approach.

Methods

This study was a review of all the data on consecutive posterior spinal fusion surgeries performed by a specific two-surgeon team during 2004–2013. Demographics, surgical variables, radiographic findings, and outcomes regarding blood loss, morbidity, and the duration of the procedure were evaluated.

Results

Eighty-five patients underwent the standard surgical exposure, and 41 patients underwent the two-step surgical technique. With the exception of BMI, neither group showed any statistically preoperative variable significant differences. None of the postoperative outcome variables were statistically significant between both surgical approaches.

Conclusions

No differences were detected in terms of using a two-step surgical approach versus the one-step standard surgical approach regarding perioperative blood loss, surgical time, or complications.

Level of evidence

Level of evidence III.

     

Does anterior shoulder balance in adolescent idiopathic scoliosis correlate with posterior shoulder balance clinically and radiographically?

Purpose

Patients with adolescent idiopathic scoliosis (AIS) often present with a disfiguring shoulder imbalance. Shoulder balance (Sh.B) is of significant importance to the patient’s self-perception. Previous studies have correlated Sh.B with respect to only the clinical posterior view correlated with radiographs. It is important, however, to address Sh.B with respect to anterior view of the patients’ shoulders as if patients were viewing in a mirror. In this study, we evaluated the anterior Sh.B and correlated it with posterior Sh.B clinically and radiographically in Lenke type 1 and 2 curves.

Method

An online scoliosis database was queried to identify 74 AIS patients with Lenke 1 (n = 55, age 15.28 ± 3.35) and 2 (n = 19, age 15.66 ± 3.72) curves with a complete set of PA radiographs and anterior and posterior photos. Radiographic measures for Sh.B included Cobb angles, T1 tilt, first rib angle, and clavicle-rib intersection angle. Clinical measures for Sh.B included inner shoulder angle, outer shoulder angle, and axillary fold angle. Regression analysis with Pearson’s correlation and ANOVA for statistical significance was used for analysis.

Results

For Lenke 1 curves, there was moderate statistically significant correlation between anterior and posterior clinical Sh.B (R = 0.35–0.41). There was only weak to moderate correlation between radiographic and clinical measures. For Lenke 2 curves, there was a weak to moderate correlation between anterior and posterior clinical Sh.B (R = 0.25–0.45), though not statistically significant. There was no statistically significant correlation between any radiographic measures and posterior Sh.B. There was, however, moderate and significant correlation between radiographic measures and anterior Sh.B.

Conclusion

There is no strong correlation between anterior and posterior clinical Sh.B, and surgeons should evaluate both sides in planning deformity correction, especially in Lenke 2 curves. None of the radiographic measures showed strong correlation (R > 0.8) with anterior or posterior clinical Sh.B. A stronger correlation existed between radiographic measures and anterior Sh.B measurements compared with posterior clinical Sh.B measurements in Lenke 2 curves further necessitating anterior evaluation in this group.     

Apical vertebral derotation in the posterior treatment of adolescent idiopathic scoliosis: myth or reality?

Introduction

Direct apical vertebral rotation represents an important goal of posterior surgery for thoracic adolescent idiopathic scoliosis (AIS), so as to obtain a better cosmetic effect and to avoid posterior thoracoplasty. However, the real effectiveness in correction of vertebral rotation, using posterior only procedures, is still open to debate. The aim of the present study is to compare the correction of axial apical rotation obtained with direct rotation procedure versus simple concave rod rotation, in patients treated by posterior fusion for thoracic AIS using pedicle screw-only construct.

Materials and methods

A retrospective review was performed on a total of 62 consecutive patients (one single institution, three different surgeons) affected by AIS, who had undergone a posterior spinal fusion with pedicle screw-only instrumentation between January 2005 and April 2008 at the reference center. All cases presented a main thoracic curve (Lenke type 1 and 2). The angle of rotation (RAsag) of the apical vertebra was measured from the preoperative and last follow-up axial CT. According to the derotation procedure, two groups were identified: a direct vertebral rotation group (DR group; n = 32 patients) and a simple concave rod rotation group (No-DR group; n = 30 patients). There were no statistical differences between the two groups, in terms of age, Risser’s sign, curve patterns, Cobb main thoracic (MT) curve magnitude and flexibility, extension of fusion, offset measurements on the coronal plane and sagittal preoperative contour.

Results

All 62 patients were reviewed at an average follow-up of 3.7 years (range 2.5–4.2 years). The DR group compared to the No-DR group showed a significantly better final correction of apical vertebral rotation (DR 63.4 % vs. No-DR 14.8 %; p < 0.05) and a greater final correction (61.3 vs. 52.4 %; p < 0.05) with better maintenance of the initial correction (−1.7° vs. −1.9°; ns) of the main thoracic curve. Concerning the coronal balance, there was the same aforementioned trend of better results in the DR group, with less final apical MT vertebra translation (DR 2.2 cm vs. No-DR 4.1 cm), greater overall change (preop-final) of lower instrumented vertebra (LIV) coronal tilt (−14.9° vs. −11.1°; p < 0.05); the final global coronal balance (C7–S1) resulted quite better in DR group, but without a significant difference. The T5–T12 kyphosis angle was quite similar in both group before surgery (DR 16.8° vs. No-DR 17.5°) and was little lower at final follow-up evaluation in direct vertebral rotation group (14.5° vs. 16.5°). The T10–L2 sagittal alignment angle was similar in each group before surgery (12.5° in DR vs. 11.8° in No-DR), and at the latest follow-up averaged 5.3° versus 8.2°, respectively. Lumbar lordosis was similar in each group before surgery (DR −42° vs. No-DR −44.1°) and at the final follow-up evaluation (−45.9° vs. −43.2°). At the latest follow-up, SRS-30 and SF-36 findings were similar between the two groups. The complication rate was higher in the simple concave rod rotation group (13.3 vs. 9.3 %), related in two cases to thoracoplasty, which was never utilized in direct rotation patients.

Conclusions

The direct vertebral rotation obtained significantly better final results, when compared to simple concave rod rotation, both concerning correction of apical vertebral rotation and magnitude of MT curve. On the other hand, the DR group presented a little reduction in T5–T12 kyphosis at follow-up, in comparison with concave rod rotation procedure. Both procedures were found to be satisfying from patients’ perspective. Nevertheless overall complication rate was higher in the simple concave rod rotation group, related mainly to thoracoplasty (2 cases), which was never necessary in direct rotation patients.     

Relative anterior spinal overgrowth in adolescent idiopathic scoliosis—result of disproportionate endochondral-membranous bone growth?

There is no generally accepted scientific theory for the etiology of adolescent idiopathic scoliosis (AIS). As part of its mission to widen understanding of scoliosis etiology, the International Federated Body on Scoliosis Etiology (IBSE) introduced the electronic focus group (EFG) as a means of increasing debate on knowledge of important topics. This has been designated as an on-line Delphi discussion. The text for this EFG was written by Professor Jack Cheng and his colleagues who used whole spine magnetic resonance imaging (MRI) to re-investigate the relative anterior spinal overgrowth of progressive AIS in a cross-sectional study. The text is drawn from research carried out with his co-workers including measurement of the height of vertebral components anteriorly (vertebral body) and posteriorly (pedicles) in girls with AIS and in normal subjects. The findings confirm previous anatomical studies and support the consensus view that in patients with thoracic AIS there is relatively faster growth of anterior and slower growth of posterior elements of thoracic vertebrae. The disproportionate anteroposterior vertebral size is associated with severity of the scoliotic curves. In interpretating the findings they consider the Roth/Porter hypothesis of uncoupled neuro-osseous growth in the spine but point out that knowledge of normal vertebral growth supports the view that the scoliosis deformity in AIS is related to longitudinal vertebral body growth rather than growth of the canal. In the mechanical mechanism (pathomechanism) they implicitly adopt the concept of primary skeletal change as it affects the sagittal plane of the spine with anterior increments and posterior decrements of vertebral growth and, in the biological mechanism (pathogenesis) propose a novel histogenetic hypothesis of uncoupled endochondral-membranous bone formation. The latter is viewed as part of an intrinsic abnormality of skeletal growth in patients with AIS which may be genetic. The hypothesis that AIS girls have intrinsic anomalies (not abnormalities) of skeletal growth related to curve progression and involving genetic and/or environmental factors acting in early life is not original. While the findings of Professor Cheng and his colleagues have added MRI data to the field of relative anterior spinal overgrowth in AIS their interpretation engenders controversy. Three new hypotheses are proposed to interpret their findings: (1) hypoplasia of articular processes as a risk factor for AIS; (2) selection from the normal population to AIS involves anomalous vertebral morphology and soft tissue factors—this hypothesis may also apply to certain types of secondary scoliosis; and (3) a new method to predict the natural history of AIS curves by evaluating cerebro-spinal fluid (CSF) motion at the cranio–cervical junction. What is not controversial is the need for whole spine MRI research on subjects with non-idiopathic scoliosis.This paper provides an edited summary of the third electronic focus group (EFG) of the International Federated Body on Scoliosis Etiology (IBSE). It contains the research of Professor JCY Cheng MD and his colleagues on relative anterior spinal overgrowth in adolescent idiopathic scoliosis (AIS) that was debated by via e-mail by IBSE members in three rounds during November 2003–October 2004. The summary including Professor Chengs statement, comments, questions, answers, and responses 1–26 was circulated by e-mail to IBSE members on 19 October 2004 and no further comments were received. Ideas presented in this summary are personal opinions and are not necessarily shared by all those within IBSE. Some details about IBSE are contained in the edited summary of the first EFG of the IBSE [59].     

Defining “successful” treatment outcomes in adolescent idiopathic scoliosis: a scoping review

Purpose

Adolescent idiopathic scoliosis (AIS) is the most common type of scoliosis that affects children aged 10–18 years old, manifesting in a three-dimensional spinal deformity. This study aimed to explore outcome measures used in defining AIS treatment success. Particularly, analyzing the extent of qualitative and quantitative (radiographic and quality of life domains) measures to evaluate AIS and whether AIS treatment approaches (surgical, bracing and physiotherapy) influences outcomes used as proxies of treatment success.

Methods

EMBASE and MEDLINE databases were used to conduct a systematic scoping review with 654 search queries. 158 papers met the inclusion criteria and were screened for data extraction. Extractable variables included: study characteristics, study participant characteristics, type of study, type of intervention approach and outcome measures.

Results

All 158 studies measured quantitative outcomes. 61.38% of papers used radiographic outcomes whilst 38.62% of papers used quantitative quality of life outcomes to evaluate treatment success. Irrespective of treatment intervention utilized, the type of quantitative outcome measure recorded were similar in proportion. Moreover, of the radiographic outcome measures, the subcategory Cobb angle was predominantly used across all intervention approaches. For quantitative quality of life measures, questionnaires investigating multiple domains such as SRS were primarily used as proxies of AIS treatment success across all intervention approaches.

Conclusion

This study identified that no articles employed qualitative measures of describing the psychosocial implications of AIS in defining treatment success. Although quantitative measures have merit in clinical diagnoses and management, there is increasing value in using qualitative methods such as thematic analysis in guiding clinicians to develop a biopsychosocial approach for patient care.

     

Natural history of adolescent idiopathic scoliosis: a tool for guidance in decision of surgery of curves above 50°

The purpose of this lecture was to give an overview of the natural history of adolescent idiopathic scoliosis (AIS), in order to serve as guidance in the decision of performing surgery or not for the specific patient with AIS. A literature review was performed. Studies concerning long-term outcome in patients with adolescent idiopathic scoliosis that had received no treatment were used. Outcome in terms of curve size, pulmonary function, back function and quality or life/social life was compared. The literature review showed that single thoracic curves of 50°–75° progress 0.73°/year over a 40-year period. AIS do not result in increased mortality, but pulmonary symptoms may be associated with larger curves. Back pain is more frequent among patients with AIS. No study using modern quality of life questionnaires exists, but for social function, childbearing, and marriage no apparent disadvantageous effects were reported compared to the healthy population. The conclusion is that most individuals with AIS and moderate curve size around maturity function well and lead an acceptable life in terms of work and family. Some patients with larger curves have pulmonary problems, but not to the extent that this affects the life span. This needs to be taken into account when discussing surgery with the individual patient.     

A large adolescent idiopathic scoliosis curve in a skeletally immature patient: is early surgery the correct approach? Overview of available evidence

The goal of this study was to determine whether the available studies provide enough evidence that, in a borderline case of adolescent idiopathic scoliosis with a large (35 to 50 degrees) curve in a skeletally immature patient (Risser 0 to 2) with significant growth potential left, a conservative line of management in the form of bracing can be considered, rather than to rush into a potentially unnecessary major spinal surgery. We reviewed the literature spanning the last 20 years for the results of bracing in this specific group of patients. From the 9 studies selected, a group-specific data extraction was carried out. Three hundred and five patients with a 36 to 50 degrees scoliosis curve and Risser stages 0 to 2 were treated by bracing and the treatment was termed successful in 160 patients. Thus, more than half (52.5%) of the patients were successfully managed with a brace and were spared surgery. The current trend for management of these curves is early surgical intervention, the rationale being the ineffectiveness of bracing in preventing the progression of such a large curve and the difficulty in obtaining satisfactory correction by postponing surgery to a later date. On the basis of our results, we propose a conservative line of management for these curves, in contrast with current views, rather than to rush into a major spine surgery, expecting a favorable outcome with a well-supervised bracing program. If the curve progresses, surgery can always be considered later, keeping in mind the excellent correction obtained with the pedicle screw systems even for large curves of 70 to 100 degrees.     

Low-density versus high-density thoracic pedicle screw constructs in adolescent idiopathic scoliosis: do more screws lead to a better outcome?

Background contextThoracic pedicle screw (TPS) constructs have improved curve correction measurements compared with hook and hybrid constructs in the treatment of adolescent idiopathic scoliosis (AIS), but the optimal implant density, or the number of screws per level, remains unknown in the treatment of flexible thoracic curves.PurposeTo determine how implant density affects clinical outcome, radiographic outcome, and cost in the treatment of Lenke Curve Type I AIS.Study designA retrospective clinical study.Patient sampleNinety-one consecutive AIS patients with Lenke Type I curves who underwent surgical correction with a minimum follow-up of 24 months.Outcome measuresRadiographic outcomes included assessment of preoperative and 2-year postoperative thoracic Cobb angle, T5–T12 kyphosis, and curve flexibility. We also assessed SRS-22 outcome measures and thoracic angle of trunk rotation (ATR) before surgery and at the 2-year postoperative time point. The cost of each construct was also evaluated.MethodsBivariate analysis was conducted between implant density and the following factors: percent correction of the major curve, ATR, and change in kyphosis. The correlation between curve flexibility and percent correction of the major curve was determined. Patients were then divided into two groups: the low-density (LD) TPS group defined by implant density below the mean number of screws per level for the entire cohort (less than 1.3 screws per level) and the high-density (HD) TPS group defined by implant density above the mean number of screws per level (more than 1.3 screws per level). Independent sample t tests were used to compare demographic data as well as radiographic and clinical outcomes at baseline and at follow-up between the two groups.ResultsSixty-one female and 30 male patients met inclusion criteria. No significant correlations were found between implant density and the following parameters: percent correction of the major curve (p=.25), ATR (p=.75), and change in T5–T12 kyphosis (p=.40). No correlation was found between curve flexibility and percent correction of the major curve (p=.54). The LD group consisted of 57 patients, whereas the HD group had 34 patients. There were no differences between the HD group and the LD group in regard to major curve correction, change in T5–T12 kyphosis, or change in ATR. Total implant costs were significantly higher in the HD group ($13,272 vs. $10,819; p<.01). The SRS-22 image domain and overall score improved at 2 years within both groups, but there were no group differences in any of the SRS-22 domains or the overall score.ConclusionsWe identified no clinical, radiographic, perioperative, or complication-related advantage of constructs with higher TPS implant density in this patient cohort with flexible idiopathic scoliosis. Cost was significantly higher with HD constructs in comparison with LD constructs. Optimal implant density chosen by the surgeon should rely on a number of factors including curve magnitude and rigidity, bone density, and desired correction.     

A level-1 pilot study to evaluate of ultraporous β-tricalcium phosphate as a graft extender in the posterior correction of adolescent idiopathic scoliosis

The objective of this study is to compare the clinical and radiographic results of ultraporous β-tricalcium phosphate (β-TCP) versus autogenous iliac crest bone graft (ICBG), through prospective randomized pilot study (EBM-Level 1), as graft extenders in scoliosis surgery. In the posterior correction of scoliosis, local bone resected as part of the procedure is used as the base bone graft material. Supplemental grafting from the iliac crest is considered the gold-standard in posterior spinal fusion. However, autograft is not available in unlimited quantities, and bone harvesting is a source of significant morbidity. Ultraporous β-TCP might be a substitute for ICBG in these patients and thus eliminate donor site morbidity. A total of 40 patients with adolescent idiopathic scoliosis (AIS) were randomized into two treatment groups and underwent corrective posterior instrumentation. In 20 patients, ICBG harvesting was performed whereas the other half received β-TCP (VITOSS^®) to augment the local bone graft. If thoracoplasty was performed, the resected rib bone was added in both groups. Patients were observed clinically and radiographically for a minimum of 20 months postoperatively, with a mean follow-up of 4 years. Overall pain and pain specific to the back and donor site were assessed using a visual analog scale (VAS). As a result, both groups were comparable with respect to the age at the time of surgery, gender ratio, preoperative deformity, and hence length of instrumentation. There was no significant difference in blood loss and operative time. In nine patients of the β-TCP group and eight patients of the ICBG group, thoracoplasty was performed resulting in a rib graft of on average 7.9 g in both groups. Average curve correction was 61.7% in the β-TCP group and 61.2% in the ICBG group at hospital discharge (P = 0.313) and 57.2 and 54.3%, respectively, at follow-up (P = 0.109). Loss of curve correction amounted on average 2.6° in the β-TCP group and 4.2° in the comparison group (P = 0.033). In the ICBG group, four patients still reported donor site pain of on average 2/10 on the VAS at last follow-up. One patient in the β-TCP group was diagnosed with a pseudarthrosis at the caudal end of the instrumentation. Revision surgery demonstrated solid bone formation directly above the pseudarthrosis with no histological evidence of β-TCP in the biopsy taken. In conclusion, the use of β-TCP instead of ICBG as extenders of local bone graft yielded equivalent results in the posterior correction of AIS. The promising early results of this pilot study support that β-TCP appears to be an effective bone substitute in scoliosis surgery avoiding harvesting of pelvic bone and the associated morbidity.     

Anterior-posterior length discrepancy of the spinal column in adolescent idiopathic scoliosis—a 3D CT study

Background Context

One of the characteristics of reported observations in adolescent idiopathic scoliosis (AIS) is that the thoracic spine is longer anteriorly than posteriorly, more pronounced around the apex than the transitional zones. This reversal of the normal kyphotic anatomy of the thoracic spine is related to questions of etiopathogenesis of AIS. The changes in the anatomy of the anterior column have been described rather in detail; however, the role of the posterior spinal column and the laminae has so far not been elucidated. If the posterior column exhibits a longitudinal growth disturbance, it could act as a tether, leading to a more or less normal anterior column with a deformed and shorter posterior aspect of the spine. So far, it has remained unclear whether this anterior-posterior length discrepancy is the result of relative anterior lengthening or relative posterior shortening, and which tissues (bone, disc, intervertebral soft tissue) are involved.

Does spinal deformity correction of non-dystrophic scoliosis in neurofibromatosis type I with one-stage posterior pedicle screw technique produce outcomes similar to adolescent idiopathic scoliosis?

Background Context

The efficacy of one-stage posterior pedicle screw instrument used in the treatment of non-dystrophic scoliosis in neurofibromatosis type I (NF-1) is unknown. Also, there is no study that has directly compared the results of spinal deformity correction between non-dystrophic scoliosis in NF-1 and adolescent idiopathic scoliosis (AIS).

Factors associated with the success of the Rigo System Chêneau brace in treating mild to moderate adolescent idiopathic scoliosis

Background

Adolescent idiopathic scoliosis (AIS) is the most prevalent spine deformity within the pediatric population. Orthosis is the mainstay of conservative treatment for mild to moderate AIS. The Rigo System Chêneau (RSC) brace is a custom-made thoracolumbar sacral orthosis (TLSO) based on a three-dimensional correction concept. The purpose of this study was to identify factors that could predict the therapeutic success/failure of the RSC brace.

Materials and methods

A retrospective cohort study was performed on all consecutive patients according to the Scoliosis Research Society (SRS) criteria for the success of conservative treatment. Participants had a 2-year follow-up beyond the termination of brace treatment. All patients were treated with the RSC orthotic device.

Results

Ninety-three patients met the inclusion criteria. At treatment onset, their average age was 12.9 years, average Cobb angle 31.97°, Risser score 1.07, and the mean angle of thoracic rotation (ATR) was 10.2°. The mean brace treatment period was 36 months. Treatment was successful in 83.8 % of these patients (n = 79). The average final Cobb angle was 28.97°, Risser score 4.88, and ATR 8.09°. The pre-treatment factors associated with the success of applying the RSC brace were a high Risser score [odds ratio (OR) = 2.97, 95 % confidence interval [CI] 1.18–7.44; p = 0.02), a low Cobb angle (OR = 0.92, 95 % CI 0.85–0.99; p = 0.02), and low ATR (OR = 0.86, 95 % CI 0.75–0.99; p = 0.04).

Conclusions

The treatment of mild to moderate AIS with the RSC brace provides excellent clinical results. Its added benefit is enabling a three-dimensional correction of a three-dimensional deformity. Pre-treatment high Risser score, low Cobb angles, and low ATRs are associated with treatment success.

Level of evidence

Retrospective analysis, Level III.