Curve Progression In Scoliosis Research Articles

Evaluation of the effectiveness of soft braces on idiopathic scoliosis: A review of literature

Background: Various treatment approaches are used for subjects with idiopathic scoliosis, however using a brace is one of the most common approaches in this regard. The braces used for idiopathic scoliosis can be divided into soft and rigid braces. SpineCor brace is mostly recommended for subjects who refused to use rigid braces. However, it is not well understood whether soft braces are as effective as rigid braces to control scoliosis curve progression or not. Therefore, this study aimed to evaluate the effectiveness of soft braces used for idiopathic scoliotic curves compared to other available braces. Method: A search was done in databases including PubMed, Google Scholar, ISI Web of Knowledge, Ebsco, Embasco, and Scopus. Keywords of the soft brace, SpineCor were used in combination with scoliosis. The quality of the selected studies was evaluated by use of the Down and Black tool, which is a reliable method to evaluate the quality of the studies. Results: Based on the aforementioned keywords, 52 studies were achieved. After reviewing the title and abstract of each study 11 papers were selected for final analysis. Eight studies were on the evaluation of the effectiveness of the SpineCor brace on scoliosis. There were three studies on the comparison of the SpineCor with other available rigid braces. Conclusion: The results of selected studies confirmed that the SpineCor brace can be used to control the progression of idiopathic scoliosis. However, its effectiveness is limited to the curves with a severity of fewer than 30° and for the patients with Risser signs 0–3. The effectiveness of SpineCor is not comparable with a rigid brace, especially for the curve above 40°. SpineCor stabilizes the spine with high compliance and with significant improvement in posture, rib hump, lumbar predominance, and muscle contraction.

Subclassification of Sanders Maturation Stage 3 Demonstrates Differences in Spine and Total Height Velocity Between 3A and 3B in Patients with Idiopathic Scoliosis.

A single-center retrospective case-control study. To compare the spine and total height velocity between Sanders maturation stage (SMS) 3A and 3B. Identifying SMS 3 is critical for treating growing children because it represents the early phase of rapid adolescent growth. However, there is limited literature available that clearly describes the growth differences between 3A and 3B. The current study included consecutive patients with idiopathic scoliosis staged SMS 3 from January 2012 to December 2021. T1-S1 spine height, total body height, and curve magnitude were measured at the initial and follow-up visits. In addition to the spine and total height velocity calculated per month, corrected height velocity was estimated for curve magnitude using a validated formula. Mann-Whitney U test was used to compare SMS 3A and 3B outcomes, followed by a multiple linear regression model to evaluate the association of the SMS subclassifications to growth velocity adjusted for confounding factors. A total of 204 patients (66% girls, mean age: 12.3±1.3y) met the inclusion criteria. Patients staged SMS 3A had higher spine height velocity (mm/month) in both girls (2.3 vs. 1.5, P<0.001) and boys (2.6 vs. 1.7, P<0.001), as well as total height velocity (mm/month; (5.8 vs. 4.3, P<0.001 for girls; 6.6 vs. 4.5, P<0.001 for boys). Corrected velocity showed similar results with greater spine and total height velocity in SMS 3A. Multivariate analysis indicated a significant association of the SMS subclassification to the spine and total height velocity. The scoliosis curve progression was comparable between SMS 3A and 3B. SMS 3A and 3B had differential growth velocity in the spine and total body height. These results advocated the significance of SMS 3 subclassification for managing scoliosis treatment, including observation, bracing, and surgical interventions with fusion and growth modulation. Level III (Case-control study).

Genetic variants associated with the occurrence and progression of adolescent idiopathic scoliosis: a systematic review protocol

BackgroundAdolescent idiopathic scoliosis (AIS) is a structural lateral spinal curvature of ≥ 10° with rotation. Approximately 2–3% of children in most populations are affected with AIS, and this condition is responsible for approximately $1.1 billion in surgical costs to the US healthcare system. Although a genetic factor for AIS has been demonstrated for decades, with multiple potentially contributory loci identified across populations, treatment options have remained limited to bracing and surgery.MethodsThe databases MEDLINE (via PubMed), Embase, Google Scholar, and Ovid MEDLINE will be searched and limited to articles in English. We will conduct title and abstract, full-text, and data extraction screening through Covidence, followed by data transfer to a custom REDCap database. Quality assessment will be confirmed by multiple reviewers. Studies containing variant-level data (i.e., GWAS, exome sequencing) for AIS subjects and controls will be considered. Outcomes of interest will include presence/absence of AIS, scoliosis curve severity, scoliosis curve progression, and presence/absence of nucleotide-level variants. Analyses will include odds ratios and relative risk assessments, and subgroup analysis (i.e., males vs. females, age groups) may be applied. Quality assessment tools will include GRADE and Q-Genie for genetic studies.DiscussionIn this systematic review, we seek to evaluate the quality of genetic evidence for AIS to better inform research efforts, to ultimately improve the quality of patient care and diagnosis.Systematic review registrationPROSPERO registration #CRD42021243253

A Predictive Model of Progression for Adolescent Idiopathic Scoliosis Based on 3D Spine Parameters at First Visit.

Prospective cohort study. The objective of the present study was to design a model of AIS progression to predict Cobb angle at full skeletal maturity, based on curve type, skeletal maturation, and 3D spine parameters available at first visit. Adolescent idiopathic scoliosis (AIS) is a three-dimensional (3D) spinal deformity that affects 1% of adolescents. Curve severity is assessed using the Cobb angle. Prediction of scoliosis progression remains challenging for the treating physician and is currently based on curve type, severity, and maturity. The objective of this study was to develop a predictive model of final Cobb angle, based on 3D spine parameters at first visit, to optimize treatment. A prospective cohort of AIS patients at first orthopedic visit was enrolled between 2006 and 2010, all with 3D reconstructions. Measurements of five types of descriptors were obtained: angle of plane of maximum curvature, Cobb angles, 3D wedging, rotation, and torsion. A general linear model analysis with backward selection was done with final Cobb angle (either just before surgery or at skeletal maturity) as outcome and 3D spine parameters and clinical parameters as predictors. Of 195 participants, 172 (88%) were analyzed; average age at presentation was 12.5 ± 1.3 years and mean follow-up to outcome, 3.2 years. The final model includes significant predictors: initial skeletal maturation, curve type, frontal Cobb angle, angle of plane of maximal curvature, and 3D disk wedging (T3-T4, T8-T9) and achieved a determination coefficient (R) = 0.643. Positive and negative predictive values to identify a curve of 35 degrees are 79% and 94%. This study developed a predictive model of spinal curve progression in scoliosis based on first-visit information. The model will help the treating physician to initiate appropriate treatment at first visit. 3.

Does an intrathecal baclofen pump impact scoliosis progression and complicate posterior spine fusion in patients with cerebral palsy?

Retrospective comparative study. In patients with cerebral palsy (CP), we determine the impact of intrathecal baclofen pumps (ITBPs) on scoliosis curve progression before posterior spine fusion (PSF) and its effects on surgical outcome. Children with CP can have rapid scoliosis progression, and high rates of surgical complications can be encountered. It is unknown whether the presence of pre-existing ITBP results in more difficult surgery and higher complication rates in similarly affected children. This is a single-center retrospective study of CP patients undergoing PSF over a 15-year period. Demographics, comorbidities, curve magnitudes, and surgical methods were compared between patients with ITBP and those without. Postoperative complications, length of intensive care unit/hospital stay, drain use and output volume, and need for further surgery were also compared. Curve progression analysis after ITBP placement was performed on a subgroup of patients with high-quality consistent radiographs. Nineteen patients with ITBP and 49 patients without ITBP met inclusion criteria. Age, comorbidities, number of levels fused, and fixation techniques during PSF were not significantly different between cohorts. ITBP patients were more likely to have PSF with osteotomy (p = 0.022). Increased intraoperative neurosurgical consultations were found for patients with ITBP (42.1% vs. 4.0%; p < 0.001). Median surgical time was 1.2h greater in patients with ITBP (6.7 vs. 5.5h, p = 0.039). There was no difference in hospital course and complications in patients with ITBP and those without ITBP. Thirty-one patients without ITB were compared with 15 ITBP patients for curve progression before PSF, demonstrating a mean rate of scoliosis progression of 9.6° ± 6.7°/year and 14.8° ± 9.1°/year (p = 0.0346), respectively. The presence of an ITBP appears to be associated with the increase in scoliosis progression; and these patients will likely have a more challenging spine fusion. Fortunately, the final outcome is not affected by ITBP. Level III.

The radiographic parameter risk factors of rapid curve progression in Lenke 5 and 6 adolescent idiopathic scoliosis: A retrospective study.

Various parameters related to growth and maturity have been shown to be risk factors for scoliosis curve progression. We previously identified correlations between curve progression and radiographic parameters in clinical practice, but there is a lack of research.The aim of this study was to investigate and identify the radiographic parameters that are risk factors for rapid curve progression in Lenke 5 or 6 adolescent idiopathic scoliosis (AIS).A retrospective review of patients who were prospectively enrolled at the initiation of brace wear and followed through completion of bracing or surgery was performed. The inclusion criteria were as follows: a Lenke type 5 or 6 classification, Risser sign grade 0 or 1 at the initial outpatient examination, a follow-up period of 6 months including a minimum of 4 follow-ups, At each visit, the whole spine x-ray was completed, the following data were measured and collected: angle of the lumbar curve (LC), rotation of the apical vertebra (RAV) in the LC, deviation of the apical vertebra (DAV) in the lumbar curve, clavicle angle, L5 tilt angle (TA), body mass index, flexibility of the LC (FLC), and peak angle velocity (PAV). A binary logistic regression analysis was used to assess the contribution of each variable to PAV onset. The touch types for the determination of the lowest instrumented vertebra (LIV) were compared at both the PAV and final follow-up.Thirty-six AIS patients were recruited. The binary logistic regression model indicated that the following variable values significantly contributed to a high risk of PAV occurrence: LC ≥30° (OR = 6.153, 95%CI = 1.683–22.488, P = .006), RAV ≥III (OR = 15.484, 95%CI = 4.535–52.865, P <.001), DAV ≥40 mm (OR = 8.599, 95%CI = 2.483–29.784, P <.001), and TA ≥10° (OR = 2.223, 95%CI = 3.094–27.563, P <.001). The touch types for LIV determination changed in 12 of 36 patients, with at least 1 segment added as the LIV between the PAV and the final visit.LC ≥30°, RAV ≥III, DAV ≥40 mm, and L5 TA≥10° were radiographic parameters associated with an increased risk of curve progression in Lenke 5 and 6 AIS. The orthopedic surgery performed at the PAV is the ideal timing, and it will preserve 1 active segment than later surgery.Level of evidence was 4.

A replication study for association of 53 single nucleotide polymorphisms in ScoliScore test with adolescent idiopathic scoliosis in French-Canadian population.

A replication association study that used genomic data generated from French-Canadian case and control cohorts. To determine whether the 53 single nucleotide polymorphisms (SNPs) that were previously associated with spinal deformity progression in an American Caucasian cohort are similarly associated in French-Canadian population. It is widely accepted that genetic factors contribute to adolescent idiopathic scoliosis. The identification of genetic variants associated with the predisposition or progression of curvature could facilitate diagnostic/prognostic tool development. Although 53 SNPs have been associated with spinal curve progression in Caucasian cohorts in the United States, these associations were not replicated in a large Japanese population study, arguing that such a discrepancy could be explained by ethnicity, thus raising the importance of a replication study in an independent Caucasian population of European descent. Genomic data were collected from the French-Canadian population, using the Illumina HumanOmni 2.5M BeadChip. Fifty-two SNPs, tested in ScoliScore or in high linkage disequilibrium with SNPs in the test, were selected to assess their association with scoliosis generally, and with spinal curve progression. One SNP in ScoliScore, rs16909285, could not be evaluated in our Genome-Wide association study. None of the SNPs used in ScoliScore were associated with adolescent idiopathic scoliosis curve progression or curve occurrence in French-Canadian population. We evaluated 52 SNPs in severe patients by comparing risk allele frequencies with those in nonsevere patients and with those in control individuals. There was no significant difference between the severe group and the nonsevere group or between the severe group and the control group. Although the 52 SNPs studied here were previously associated with curve progression in an American population of European descent, we found no association in French-Canadian patients with adolescent idiopathic scoliosis. This second replication cohort suggests that the lack of association of these SNPs in a Japanese cohort is not due to ethnicity. 4.

Monitoring for idiopathic scoliosis curve progression using surface topography asymmetry analysis of the torso in adolescents

Background contextAt first visit and each clinical follow-up session, patients with adolescent idiopathic scoliosis (AIS) undergo radiographic examination, from which the Cobb angle is measured. The cumulative exposure to X-ray radiation justifies efforts in developing noninvasive methods for scoliosis monitoring. PurposeTo determine the capability of the three-dimensional markerless surface topography (ST) asymmetry analysis to detect ≥5° progression in the spinal curvature in patients with AIS over 1-year follow-up interval. Study design/settingCross-sectional study in a specialized scoliosis clinic. Patient sampleIn this study, baseline and 1-year follow-up full torso ST scans of 100 patients with AIS were analyzed using three-dimensional markerless asymmetry analysis. Outcome measuresPatients with ΔCobb≥5° and ΔCobb<5° were categorized into progression and nonprogression groups, respectively. MethodsThe ST scan of each full torso was analyzed to calculate the best plane of symmetry by minimizing the distances between the torso and its reflection about the plane of symmetry. Distance between the torso and its reflection was measured and displayed as deviation color maps. The difference of ST measurements between two successive acquisitions was used to determine if the scoliosis has progressed at least 5° or not. The classification tree technique was implemented using the local deformity of the torso in the thoracic–thoracolumbar (T–TL) and lumbar (L) regions to categorize curves into progression and nonprogression groups. The change in maximum deviation and root mean square of the deviations in the torso were the parameters effective in capturing the curve progression. Funding for this research is provided by the Scoliosis Research Society, and Women and Children's Health Research Institute. ResultsThe classification model detected 85.7% of the progression and 71.6% of the nonprogression cases. The resulting false-negative rate of 4% for T–TL curves, representing the proportion of undetected progressions, confirmed that the technique shows promise to monitor the progression of T–TL scoliosis curves. Although 100% L curves with progression were detected using the deviation color maps of the torsos, because of the small number of analyzed L curves, further research is needed before the efficiency of the method in capturing the L curves with progression is confirmed. ConclusionsUsing the developed classification tree for the patients analyzed in this study, 43% of nonprogression cases between two visits would not have to undergo an X-ray examination.

AIS and spondylolisthesis

The association of scoliosis and spondylolisthesis is well documented in literature; the nature and modalities of the relationship of the two pathologies are variable and not always clear. Also, etiologic particulars of scoliosis associated with spondylolisthesis are not well defined, even in cases where scoliosis is called idiopathic. In this paper, we review previous literature and discuss the different aspects of the mutual relationship of scoliosis and spondylolisthesis in the adolescent age. It is a common notion that the highest occurrence of scoliosis associated with spondylolisthesis is at the lumbar level, both in adolescent and in adult patients. It is probable that the scoliosis that is more heavily determined by the presence of spondylolisthesis is at the lumbar level and presents curve angle lower than 15° Cobb and mild rotation. The scoliosis with curve value over 15° Cobb that is present at the lumbar level in association with spondylolisthesis probably is not prominently due to spondylolisthesis: in these cases, spondylolisthesis is probably only partially responsible for scoliosis progression with a spasm mechanism and/or due to rotation of slipping "olisthetic" vertebra. We think that the two pathologies should be treated separately, as stated by many other authors, but we would highlight the concept that, whatever be the scoliosis curve origin, spasm, olisthetic or mixed together, this origin has no influence on treatment. The curves should be considered, for all practical effects, as so-called idiopathic scoliosis. We think that generally patient care should be addressed to treat only spondylolisthesis or only scoliosis, if it is necessary on the basis of clinical findings and therapeutic indications of the isolated pathologies, completely separating the two diseases treatments. Scoliosis should be considered as an independent disease; only in the case of scoliosis curve progression over time, associated scoliosis must be treated, according to therapeutic principles of the care of any so-called idiopathic scoliosis of similar magnitude, and a similar approach must be applied in the case of spondylolisthesis progression or painful spondylolisthesis.

Does pregnancy increase curve progression in women with scoliosis treated without surgery?

Study design: Systematic review.Study rationale: It is commonly believed that scoliosis treated nonoperatively does not worsen in pregnancy; however, at times patients with scoliosis progress rapidly during these months.Objective or clinical question: What is the level of evidence to support or deny the claim that scoliosis treated nonoperatively does not worsen in pregnancy?Methods: A systematic review of the literature was undertaken for articles published through March 2011. PubMed, Cochrane, National Guideline Clearinghouse Databases as well as bibliographies of key articles were searched. Two independent authors reviewed articles. Inclusion and exclusion criteria were set and each article was subject to a predefined quality-rating scheme.Results: We identified two articles meeting our inclusion criteria. There was no difference in risk of curve progression > 5° or > 10° between women who had one or more pregnancies compared with those who had never been pregnant. However, among women who had been treated with an orthosis, those with one or more pregnancies had a higher risk of curve progression > 5° compared with never-pregnant women: relative risk = 8.1 (95% confidence interval: 1.8–35.8) in one study and 1.9 (95% confidence interval: 0.8–4.3) in the other. While women with more severe curves had a higher risk of curve progression, having one or more pregnancies did not appear to modify the effect of curve severity.Conclusions: Having one or more pregnancies does not appear to affect curve progression in scoliosis. However, among patients who had prior orthotic treatment, there is some evidence to suggest that women experiencing one or more pregnancies had a higher risk of curve progression compared with never-pregnant women. The overall strength of evidence for this conclusion is low.

Scoliosis associated with syringomyelia: analysis of MRI and curve progression

Little is known about the natural history of scoliosis found in patients with syringomyelia, including the factors affecting scoliosis curve progression and the effect of syrinx drainage treatment. Twenty patients having scoliosis with syringomyelia diagnosed by MRI were followed up for 6.6 (range 2.0-12.6) years on an average. Various factors potentially influencing curve pattern or progression in these patients were then retrospectively reviewed. The convex side of major curve of scoliosis tended to be on the same side as the syrinx and as the unilateral neurologic abnormality. No correlation was found between the location and the size of the syrinx and the location and size of the major curve of the scoliosis, or between the severity of neurologic deficit and the size of the major curve of the scoliosis. In patients under the age of ten at the time of diagnosis of scoliosis and with a flexible curve, decompression of the syrinx improved or stabilized scoliosis. In most patients over the age of ten, surgical treatment of the scoliosis was necessary because of the large initial size of the curve or progression of the curve even after syrinx drainage. Other factors including gender, location of the syrinx, type of the curve, and severity of neurologic deficits did not correlate with the progression of the curve. The results of this retrospective study suggest that early diagnosis and decompression of a syrinx in scoliosis patients especially under the age of ten is crucial and may decrease the curve size and limit scoliosis curve progression.

The Associated Effects of Untreated Unilateral Hip Dislocation in Cerebral Palsy Scoliosis

The presence of a unilateral hip dislocation in children with cerebral palsy (CP) may cause problems with sitting imbalance, pressure ulcers, and hip pain. There is a dynamic interplay between hip dislocation, pelvic obliquity (PO), and scoliosis. The effect of an untreated unilateral hip dislocation on the rate of curve progression of CP scoliosis has not been defined in the literature. The purpose of this study is to investigate the effect of unilateral hip dislocation on PO and the rate of curve progression in children with spastic quadriplegic CP. Patients with spastic quadriplegic CP who had spine radiographs at the time of initial presentation with scoliosis and at the latest follow-up were evaluated. Twenty-three children with spastic CP who had an untreated unilateral hip dislocation and scoliosis constituted the study group. The control group consisted of 83 quadriplegic CP patients with scoliosis and well-located hips. The rate of curve progression, incidence of PO, and the rate of PO progression at follow-up were compared between the 2 groups. The mean ages of patients with a unilateral dislocation and with well-located hips at initial radiograph were 10.4 and 10.5 years, respectively. The mean follow-up was 3.5 years. The mean rate of scoliosis curve progression in patients with a unilateral hip dislocation was 12.9 degrees per year. In the control group, the mean progression rate was 12.2 degrees per year. The incidence of PO at follow-up was 74% in scoliotic patients with a dislocation and 63% in scoliotic patients with normal hips. Using repeated-measures analysis of variance, unilateral hip dislocation was found to have no significant effect on scoliosis progression; however, progression of PO was significantly increased in the hip dislocation group (P < 0.05). Pelvic obliquity was corrected after posterior spinal fusion to the sacrum with pelvic fixation, without reducing the hip(s) at the same surgery. Unilateral hip dislocation causes a significant increase of PO but does not affect the rate of scoliosis curve progression.

Growth and Curve Stabilization in Girls With Adolescent Idiopathic Scoliosis

A retrospective study of a cohort of 132 girls with adolescent idiopathic scoliosis (AIS). Evaluate the changes in height and scoliosis angle over time by the use of a mathematical model and determine a relationship between height and angle values in patients with AIS. The influence of growth on idiopathic scoliosis (IS) is still not fully understood. Although it has not been completely demonstrated, it is accepted that a relationship exists between height growth and curve progression, as well as that curve stabilization occurs when growth ends, but it has not yet been demonstrated whether both occur at the same time. One hundred thirty-two girls were included in a retrospective study. Inclusion criteria were: adolescent IS, Cobb angle > or =10 degrees , menarche age well documented, and follow-up of at least 2 years in 6-month controls. Main variables were: menarche age, height, Cobb angle, and treatment. Height and angle changes over the time were adjusted by several curvilinear regression models. Calculations were made of the gradient between each consecutive time point (first derivative function). Growth was considered as tending to stabilize when the function gradient changed its sign or was negligible. Height and Cobb angle correlation coefficients for repeated measures were estimated within patients for curves managed with observation and curves managed with a brace. Comparisons among these correlations were based on the Fisher-Z transformation. Height function gradient changed sign at 1 year postmenarche, and Cobb angle function gradient was negligible around menarche. There was a correlation between mean heights and mean angles, being higher for girls managed only with observation. When comparing mean heights in one semester with the mean heights of the previous one, there were statistically significant differences until 2.5 years postmenarche, although after the first year, these differences were clinically irrelevant. A significant increase for angle values was observed in the same period for the group of girls managed with observation and in the 6 months before menarche for the girls managed with a brace. A mathematical model was used to demonstrate when height and angle growths tend to stabilize (1 year after menarche for height values and at the time of menarche for angle values) in AIS. In the absence of a brace effect, a significant correlation between both growth rates was noted up until 2.5 years after menarche.

Scoliosis Associated With Chiari I Malformations: The Effect of Suboccipital Decompression on Scoliosis Curve Progression

A retrospective review of the effect of suboccipital decompression and duraplasty on curve progression in 22 patients who presented with scoliosis, syringomyelia, and a Chiari 1 malformation. To document the clinical characteristics of scoliosis in association with a Chiari 1 malformation, determine the effects of suboccipital decompression and duraplasty on scoliosis curve progression over time, and identify the clinical factors (age, gender, and curve characteristics) that may be associated with a clinical improvement in the scoliotic deformity after suboccipital decompression. Prior publications have documented the clinical characteristics, signs, and symptoms of the Chiari 1 malformation. An association between Chiari 1 malformations, syringomyelia, and scoliosis has been recognized and reported. Several authors have also reported on the response of the scoliotic curve to Chiari 1 decompression, but the number of patients in these reports has been small. This cohort represents the largest number of patients to date (21) with Chiari 1 malformations, syringomyelia, and scoliosis who have been treated and followed over time in order to determine the effect of decompression on curve progression. A retrospective case review of 85 patients, age 16 years or less, who underwent posterior fossa decompression for a Chiari 1 malformation between 1990 and November 2000. A subset of 7 males and 15 females (22 of 85 total patients) who initially presented with scoliosis and were then found to have a Chiari 1 malformation was selected from this larger cohort for further review. The orthopedic and neurosurgical charts, spinal radiographs, and magnetic resonance imaging scans were then reviewed for each of these patients. Twenty-one of the 22 patients who presented with scoliosis met the inclusion criteria of having a Chiari 1 malformation, scoliosis, and an unfused spine during the follow-up period after suboccipital decompression. One patient had a posterior spinal fusion before suboccipital decompression and was excluded from further review. Thirteen patients of the 21 study patients (62%) had curve improvement or stabilization during the follow-up period. Eight of 21 patients (38%) had curve progression. Closer analysis reveals that the age, gender, and initial size of the scoliotic curve influenced the results of suboccipital decompression on the behavior of the scoliosis. Specifically, 10 of 11 patients (91%) who were less than 10 years of age at the time of suboccipital decompression have had their curves improve or stay the same during follow-up. In contrast, 5 of 7 female patients (72%) older than 10 years old with a curve greater than 40 degrees before suboccipital decompression have either been fused or are awaiting fusion.

Curve progression in scoliosis associated with Chiari I malformation following suboccipital decompression.

Nine children with scoliosis and Chiari I malformations were followed 1-11 years after suboccipital decompression. Eight also had syringomyelia. Despite initial curve stabilization, at final follow-up eight curves were of the magnitude to require spinal fusion. Neither bracing nor secondary neurosurgical procedures arrested progressive curves.

Scoliosis and Chiari 1 malformations: the influence of surgical decompression on scoliosis curve progression

John T. Smith, MD, Douglas Brockmeyer, MD, Salt Lake City, UT, USAPurpose: The surgical management of Chiari 1 malformations is controversial. There is a subset of patients with Chiari 1 malformations that develop scoliosis. Within this group, some may develop a syrinx as well. The exact relationship between Chiari 1 malformation, scoliosis and the presence of a syrinx remains unclear. Previous studies have documented a highly variable response between suboccipital decompression and improvement in scoliosis. The purpose of this study is to review our experience with suboccipital decompression for the management of Chiari 1 malformation and analyze the response of the syrinx and the scoliotic curve to surgical decompression.Methods: This is a retrospective review of 85 patients, age 16 years or younger, who underwent surgical decompression for Chiari 1 malformation between 1990 and November 2000. Of these patients, 22 presented with the initial physical finding of scoliosis. Twenty of the 22 patients had an associated syrinx of variable size. One patient had a scoliosis fusion before recognition of their Chiari 1 malformation and syrinx. Fifteen of the 22 curves were convex to the left, and 7 of 22 were convex to the right. All patients were initially managed with suboccipital decompression, C1 laminectomy, lysis of the arachnoid space and duraplasty followed by layered closure of the wound. The mean follow-up for the series was 3.8 years (range, 3 months to 10 years). Patients were followed with plain radiographs to monitor the scoliosis and serial magnetic resonance imaging to evaluate the effect of the decompression on the syrinx.Results:Table 1Table 1*Initial curve (degrees)PatientsImproved worseImprovedWorseFused0–201120–30881230–4033140–507743>502211Total2112274*One patient had fusion before recognition of the Chiari malformation and syrinx. summarizes the response of 21 patients with Chiari 1 malformation and scoliosis to the initial suboccipital decompression. The magnitude of the initial scoliosis was variable; 55% had curves greater than 30 degrees. Fifty-seven percent of curves improved after initial decompression, but 33% worsened. Four of the 21 patients have required fusion for curve progression, with an additional three patients anticipating surgery because of worsening of their curve. Curve progression was greatest for curves greater than 40 degrees at the time of initial presentation. All syrinxes improved with decompression, although the degree of response was variable and difficult to quantify. However, the degree of syrinx improvement did not correlate with curve improvement. There were four complications in the series. One syrinx required shunting after decompression, hydrothorax (1), syringopleural shunt revision (1) and pseudomeningocele repair (1).Conclusion: In this series, 57% of patients presenting with scoliosis, Chiari 1 malformation and syrinx, demonstrated improvement in their curve after suboccipital decompression. Improvement in the scoliosis curve was variable and did not have a consistent relationship with either age at initial presentation or curve severity. After initial improvement, some curves will begin to worsen over time, necessitating careful follow-up until the completion of growth. Curves that are greater than 40 degrees at the time of initial presentation are more likely to progress despite decompression. The response of the syrinx to initial decompression did not predict which curves would be progressive. Early detection and treatment of Chiari 1–related scoliosis remains beneficial, because long-standing significant curves are unlikely to improve after decompression.

Effects of age and sex on the external induction of scoliosis in rats.

To guide inquiries into the mechanisms for progression of mild scoliosis in humans, the authors investigated the effects of age and sex on the response of spines to externally applied deforming moments using a rat model. Groups of male and female rats, with initial ages of 3, 6, or 24 weeks, were held for five weeks in restraints that laterally deformed their trunks. In response to these deforming moments, the spine of every animal studied acquired an at-least-temporarily fixed lateral curve. Without exception, when deforming moments were applied, the rats' spines deformed. Neither age nor sex was an important factor in this response. The implications of these results to possible mechanisms of scoliosis curve progression in humans are discussed.