Scoliosis最新文献

Background: It has been thought that corrective posterior surgery for adolescent idiopathic scoliosis (AIS) should be started on the concave side because initial convex manipulation would increase the risk of vertebral malrotation, worsening the rib hump. With the many new materials, implants, and manipulation techniques (e.g., direct vertebral rotation) now available, we hypothesized that manipulating the convex side first is no longer taboo.

Methods: Our technique has two major facets. (1) Curve correction is started from the convex side with a derotation maneuver and in situ bending followed by concave rod application. (2) A 6.35 mm diameter pure titanium rod is used on the convex side and a 6.35 mm diameter titanium alloy rod on the concave side. Altogether, 52 patients were divided into two groups. Group N included 40 patients (3 male, 37 female; average age 15.9 years) of Lenke type 1 (23 patients), type 2 (2), type 3 (3), type 5 (10), type 6 (2). They were treated with a new technique using 6.35 mm diameter different-stiffness titanium rods. Group C included 12 patients (all female, average age 18.8 years) of Lenke type 1 (6 patients), type 2 (3), type 3 (1), type 5 (1), type 6 (1). They were treated with conventional methods using 5.5 mm diameter titanium alloy rods. Radiographic parameters (Cobb angle/thoracic kyphosis/correction rates) and perioperative data were retrospectively collected and analyzed.

Results: Preoperative main Cobb angles (groups N/C) were 56.8°/60.0°, which had improved to 15.2°/17.1° at the latest follow-up. Thoracic kyphosis increased from 16.8° to 21.3° in group N and from 16.0° to 23.4° in group C. Correction rates were 73.2% in group N and 71.7% in group C. There were no significant differences for either parameter. Mean operating time, however, was significantly shorter in group N (364 min) than in group C (456 min).

Conclusion: We developed a new corrective surgical technique for AIS using a 6.35 mm diameter pure titanium rod initially on the convex side. Correction rates in the coronal, sagittal, and axial planes were the same as those achieved with conventional methods, but the operation time was significantly shorter.

Background: The objective of this study was to evaluate shoulder balance following posterior spinal fusion for thoracic adolescent idiopathic scoliosis (AIS).

Methods: Twenty-four patients (22 females) with thoracic AIS who had undergone posterior fusion with segmental pedicle screws were retrospectively reviewed. The mean follow-up duration was 29 (range, 24-55) months. Fifteen patients had type 1 curves, seven had type 2 curves, and two had type 3 curves according to the Lenke classification. The proximal thoracic (PT) and main thoracic (MT) Cobb angles, percent correction of PT (PTC) and MT (MTC) curves, T1 tilt, and shoulder asymmetry according to radiographic shoulder height (RSH) were measured on preoperative, immediately postoperative, and final follow-up radiographs. The preoperative PT and MT curve side-bending percent correction (PTBC and MTBC) were also measured. The PTC:MTC ratio was employed as an index of PTC and MTC matching. Patients were divided into two groups according to radiographic findings immediately postoperatively: the balanced group (|RSH| <20 mm) and imbalanced group (|RSH| ≥20 mm). The preoperative indices (RSH, PTBC, MTBC, PTC, and MTC), preoperative and postoperative T1 tilt, and PTC:MTC ratio were compared between the two groups.

Results: The mean PT and MT were 33.0° and 64.2° preoperatively, 16.1° (50.5%) and 16.8° (74.0%) immediately postoperatively, and 16.9° (49.0%) and 19.2° (70.3%) at final follow-up, respectively. The mean preoperative RSH of -12.3 mm changed to +11.1 mm immediately postoperatively and improved to +5.7 mm at final follow-up. Seventeen patients were "balanced" and seven were "imbalanced" immediately postoperatively. There were significant differences in the PTC (p=0.04), postoperative T1 tilt (p=0.04), and PTC:MTC ratio (p=0.02) between the two groups (Wilcoxon rank-sum test). Only one patient had an imbalanced shoulder at the final follow-up. She had marked shoulder imbalance immediately postoperatively (RSH: +40 mm).

Conclusions: Sufficient correction of PT curves that is matched with correction of MT curves is necessary to prevent postoperative shoulder imbalance. Almost all patients in our series had satisfactory results in terms of shoulder balance at final follow-up, but one patient with marked shoulder imbalance immediately postoperatively may have residual long-term shoulder imbalance.

Background: The Rib Index, (RI), extracted from the double rib contour sign (DRCS) on lateral spinal radiographs to evaluate rib hump deformity, (RHD), in idiopathic scoliosis, (IS), patients, has been previously introduced. Although various papers using the RI have been published, no study on its reproducibility has been reported. The aim of this report is to estimate the variations of the RI in a number of a pair set of lateral chest radiographs (LCRs). The hypothesis was that the RI should have minimal variability for each subject having successive LCRs.

Methods: Seventy randomized patients who were treated in the hospital for lung diseases (mainly pneumonia or other communicable lung diseases), were initially included in the study. Each of these patients had two successive LCRs (named A and B group of radiographs) at the radiological department of the hospital, by the same technician, during the course of their treatment. The radiation source - patient distance was constant. LCRs obtained at an incorrect patient's position, or from patients who underwent a thoracic intervention and all LCRs with symmetric hemi-thoraces were excluded from the study. The LCRs of 49 patients were deemed suitable for inclusion in the study. The RI was calculated in both (A and B) LCRs of each patient. The statistical analysis included the following techniques: paired t-test, Pearson correlation coefficient and intra- and inter-observer error using the formula (SD/√2)/2, where SD is this of the differences of the two sets of measurement (As-Bs). The SPSS v16 statistical package was used.

Results: In the 49 pairs of LCRs there was no statistical difference of the RI, (paired t-test p< 0.314). The RI in the A and B group of LCRs was perfectly correlated (correlation coefficient = 0,924, p < 0.0001). The intra-observer error was 0.0080 while the inter-observer error 0.0213 in terms of 95% CI.

Conclusion: The RI proves to be a reliable method to evaluate the thoracic deformity and the effect of surgical or non-operative treatment on the IS RHD. RI is a simple method, a safe reproducible way to assess the RHD based on lateral radiographs, without the need for any further special radiographs and exposure to additional radiation.

Objectives: Effectiveness of brace treatment for adolescent idiopathic scoliosis (AIS) was demonstrated by the BrAIST study in 2013. Objectives of this study were to confirm its effectiveness by analyzing our results and to clarify the factors affecting the results of the treatment.

Materials and methods: According to the Scoliosis Research Society AIS brace studies standardization criteria, patients with age 10 years or older, Risser 0 to II, less than 1 year post-menarche, curve magnitude 25 to 40 degrees before brace treatment and who received no prior treatment were included in the study. At skeletal maturity, the rate of the patients whose curve was stabilized, exceeded 45 degrees, and who were recommended or underwent surgery were investigated. Additionally, initial correction rate by the brace and factors affecting the results were investigated.

Results: A total of 33 patients (27 females and 6 males) could be followed-up until their skeletal maturity and included in the analysis. An average age was 11.9 years, average Cobb angle was 30.8°, and Risser sign was 0 in 13 patients, I in 5, and II in 15 patients before treatment. There were 13 thoracic curves, 14 thoracolumbar or lumbar curves, and 6 double curves. Initial correction rate by the brace was 53.8% for the total curves. In terms of curve pattern, 34.4% for thoracic curve, 73.9% for thoracolumbar or lumbar curve, and 48.8% for double curve. After an average follow-up period of 33 months, 8 patients improved in more than 6 degrees, change of 17 patients were within 6 degrees, and 8 progressed in more than 6 degrees. Therefore, totally, 76% (25/33) of the curves were stabilized by the treatment. Four curves (12%) exceeded 45 degrees and one patient (3%) underwent surgery. Our results were better than the reported natural history. Factors that affected the results were hump degree before treatment and initial correction rate by the brace.

Conclusions: 76% of the curve with AIS could be stabilized by brace treatment. Brace treatment was effective for treatment of AIS. Factors affecting the results were hump degrees and initial correction rate.

Background: Recent studies have demonstrated sagittal spinal balance was more important than coronal balance in terms of clinical result of surgery for adult spinal deformity. Notably, Schwab reported that one of the target spinopelvic parameters for corrective surgery was that pelvic incidence (PI) minus lumbar lordosis (LL) should be within +/- 10 °. The present study aimed to investigate whether the clinical outcome of corrective fusion surgery was really poor for patients who could not acquire sufficient PI-LL value through the surgery.

Methods: The present study included 13 patients (mean 68.5 yrs old) with adult spinal deformity. Inclusion criteria were corrective fusion surgery more than 4 intervertebral levels, PI-LL ≥10° on the whole spine X-ray immediately after surgery, and follow-up period ≥3 years. All surgeries were performed by posterior approach. Parameters using SRS-Schwab classification, proximal junctional kyphosis (PJK) of ≥15°, implants loosening, and non-union were investigated using the total standing spinal X-ray. Clinical outcomes were evaluated by Japanese Orthopaedic Association scores (JOA score), Oswestry Disability Index, SF-36, Visual Analog Scale for low back pain, and satisfaction for surgery using SRS-22 questionnaire.

Results: All patients showed the PI-LL ≥20° before surgery. Although the LL were acquired mean 23.6° after surgery, significant loss of correction was observed at final follow up. The acquired coronal spinal alignment was maintained within the follow-up period. However, sagittal vertical axis (SVA) was shifted forward significantly, from mean 4.5cm immediately after surgery to 11.1cm at final follow-up. Five patients showed PJK, 10 patients showed implants loosening, 8 patients showed non-union at final follow-up. The JOA score and mental health summary measures of SF-36 were significantly improved at final follow-up. The satisfaction score was mean 3.3 points, including 3 patients with ≥4 points, at final follow-up. The satisfaction score correlated negatively with SVA at final follow-up (ρ=-0.58 p=0.03).

Conclusions: The forward shift of SVA was frequently observed, and SVA at final follow-up related to the patient's satisfaction of surgery. This study indicated the importance of postoperative PI-LL value, but also noted 23% of patients acquired good SVA and satisfaction nevertheless they had inadequate postoperative LL.

Background: Improvement of material property in spinal instrumentation has brought better deformity correction in scoliosis surgery in recent years. The increase of mechanical strength in instruments directly means the increase of force, which acts on bone-implant interface during scoliosis surgery. However, the actual correction force during the correction maneuver and safety margin of pull out force on each screw were not well known. In the present study, estimated corrective forces and pull out forces were analyzed using a novel method based on Finite Element Analysis (FEA).

Methods: Twenty adolescent idiopathic scoliosis patients (1 boy and 19 girls) who underwent reconstructive scoliosis surgery between June 2009 and Jun 2011 were included in this study. Scoliosis correction was performed with 6mm diameter titanium rod (Ti6Al7Nb) using the simultaneous double rod rotation technique (SDRRT) in all cases. The pre-maneuver and post-maneuver rod geometry was collected from intraoperative tracing and postoperative 3D-CT images, and 3D-FEA was performed with ANSYS. Cobb angle of major curve, correction rate and thoracic kyphosis were measured on X-ray images.

Results: Average age at surgery was 14.8, and average fusion length was 8.9 segments. Major curve was corrected from 63.1 to 18.1 degrees in average and correction rate was 71.4%. Rod geometry showed significant change on the concave side. Curvature of the rod on concave and convex sides decreased from 33.6 to 17.8 degrees, and from 25.9 to 23.8 degrees, respectively. Estimated pull out forces at apical vertebrae were 160.0N in the concave side screw and 35.6N in the convex side screw. Estimated push in force at LIV and UIV were 305.1N in the concave side screw and 86.4N in the convex side screw.

Conclusions: Corrective force during scoliosis surgery was demonstrated to be about four times greater in the concave side than in convex side. Averaged pull out and push in force fell below previously reported safety margin. Therefore, the SDRRT maneuver was safe for correcting moderate magnitude curves. To prevent implant breakage or pedicle fracture during the maneuver in a severe curve correction, mobilization of spinal segment by releasing soft tissue or facet joint could be more important than using a stronger correction maneuver with a rigid implant.

Background: Much attention has been paid to peak height velocity (PHV) as a possible predictor of curve progression in patients with idiopathic scoliosis (IS). The aim of this study was to analyze the relationship between the magnitude of the Cobb angle at PHV and scoliosis progression, defined as having surgery prior to skeletal maturity in female patients with IS.

Methods: A retrospective review identified 56 skeletally immature female IS patients who were followed until maturity. The mean age and the mean pubertal status at the initial visit were 10 years and 24 months before menarche respectively, with a follow-up period of 5 years. They were divided into two groups: non-surgery group (NS) and surgery group (S), depending on their treatment method in use at the final follow-up visit. Surgery group was defined as an ultimately having surgery due to Cobb angle greater than 45 degrees prior to skeletal maturity regardless of conservative management. Height measurements were recorded at each visit; height velocity was calculated as the height change, in cm, divided by the time interval, in years. The PHV, chronological age at PHV (APHV), height at PHV (HPHV), and final height (FH) were determined for each group. In patients with Cobb angle greater than 30 degrees, the corrected height was calculated by Kono formula and corrected height velocity values were provided. The sensitivity, specificity, and area under the curve (AUC) of the receiver-operating -characteristic (ROC) analysis were calculated to predict spinal curve progression for various Cobb-angle cutoff values at PHV.

Results: The corrected PHV had a mean value of 8.5 and 8.9 cm/year in the NS-group and S-group, respectively. The APHV was 11.9 and 11 years, the corrected HPHV was 152.9, and 149.3 cm, and the corrected FH was 159.9 and 159.3 cm, respectively. When a Cobb angle of 31.5 degrees was at PHV, ROC analysis revealed 78% sensitivity, 82% specificity, and an AUC of 0.93, acceptable values for curve progression in patients with IS.

Conclusions: These findings indicate that 31.5 degrees of spinal curvature when patients are at PHV is a significant predictive indicator for progression of the curve to a magnitude requiring surgery. We suggest that the curve-progression risk assessment in patients with IS should include PHV, along with measures of skeletal and non-skeletal maturities.

Background: Surgical treatments for early onset scoliosis (EOS), including growing rod constructs, involve many complications. Some are due to biomechanical factors. A construct that is more flexible than current instrumentation systems may reduce complications. The purpose of this preliminary study was to determine spine range of motion (ROM) after implantation of simulated growing rod constructs with a range of clinically relevant structural properties. The hypothesis was that ROM of spines instrumented with polyetheretherketone (PEEK) rods would be greater than metal rods and lower than noninstrumented controls. Further, adjacent segment motion was expected to be lower with polymer rods compared to conventional systems.

Methods: Biomechanical tests were conducted on 6 skeletally immature porcine thoracic spines (domestic swine, 35-40 kg). Spines were harvested after death from swine that had been utilized for other studies (IACUC approved) which had not involved the spine. Paired pedicle screws were used as anchors at proximal and distal levels. Specimens were tested under the following conditions: control, then dual rods of PEEK (6.25 mm), titanium (4 mm), and CoCr (5 mm) alloy. Lateral bending (LB) and flexion-extension (FE) moments of ±5 Nm were applied. Vertebral rotations were measured using video. Differences were determined by two-tailed t-tests and Bonferroni correction with four primary comparisons: PEEK vs control and PEEK vs CoCr, in LB and FE (α=0.05/4).

Results: In LB, ROM of specimens with PEEK rods was lower than control at each instrumented level. ROM was greater for PEEK rods than both Ti and CoCr at every instrumented level. Mean ROM at proximal and distal noninstrumented levels was lower for PEEK than for Ti and CoCr. In FE, mean ROM at proximal and distal noninstrumented levels was lower for PEEK than for metal. Combining treated levels, in LB, ROM for PEEK rods was 35% of control (p<0.0001) and 270% of CoCr rods (p<0.01). In FE, ROM with PEEK was 27% of control (p<0.001) and 180% of CoCr (p<0.01).

Conclusions: PEEK rods decreased flexibility versus noninstumented controls, and increased flexibility versus metal rods. Smaller increases in ROM at proximal and distal adjacent motion segments occurred with PEEK compared to metal rods, which may help decrease junctional kyphosis. Flexible growing rods may eventually help improve treatment options for young patients with severe deformity.

Background: Lenke 5C type adolescent idiopathic scoliosis (AIS) with a Cobb angle of over 30 degrees has high risk of progression. The need for corrective surgeries for degenerative lumbar scoliosis has been increasing these days and some of those cases are pre-existing type scoliosis. However, it is said to be difficult to differentiate pre-existing type scoliosis from de novo type scoliosis. The purpose of this study is to analyze the relevant X ray metrics of degenerative lumbar scoliosis and to discover differences between pre-existing and de novo type scoliosis.

Methods: Of 54 consecutive patients who were diagnosed as candidates for corrective surgery for left convex thoracolumbar / lumbar scoliosis since December 2008, 19 patients over age 50 were included in this study. The average age was 60 years old (50-80 years old). All patients were female. Coronal and sagittal parameters were contrasted between two groups divided according to the existence of scoliosis in their adolescence; clear (AIS) and unclear (de novo).

Results: Eleven were AIS, and 8 were de novo. The average age was 54.0 years old for AIS and 67.4 for de novo (p<0.05). Cobb angles (69°, 49°) and L4 tilt (30°, 22°) were found to be significantly greater in AIS. Nash-Moe rotation assessment showed that rotational deformity was greater in AIS type than in de novo type. Lumbar lordosis (28°, 32°), thoracolumbar kyphosis (24°, 12°), sagittal vertical axis (37mm, 58mm), and pelvic incidence (51°, 60°) showed no significant difference between the groups, however, pelvic tilt (24°, 33°) showed significant difference.

Conclusions: Among patients over 50 with degenerative thoracolumbar / lumbar scoliosis, those with pre-existing type scoliosis were found to have greater Cobb angle, greater L4 tilt, greater rotational deformity, less pelvic tilt, and were candidates for surgery at a younger age than those with de novo type scoliosis. In other words, those with de novo type scoliosis have less coronal deformity and worse sagittal pelvic alignment than those with pre-existing type scoliosis and are not considered candidates for surgery until a more advanced age. This study demonstrates some differences between pre-existing and de novo type scoliosis, contrasts the natural history of the two types of candidates for thoracolumbar / lumbar scoliosis surgery, and suggests the importance of performing surgery for Lenke 5C type adolescent idiopathic scoliosis at a younger age.

Background: Numerous designs are used to the treatment of Early Onset Scoliosis. For example, a Thoraco-Lumbo-Sacral Orthosis (TLSO) is constructed using Polyethylene (PE). In addition, a series of castings has been implemented using cast material (3M, BSN Medical). The cast material has some significant advantages over the PE design including: growth preserving, improved compliance, decreased invasiveness, delaying or avoiding surgery, and the ability to allow the skin to breathe. However, the mechanical effectiveness of the cast material brace as compared to the TLSO is unknown, thus providing the objective of this study.

Methods: A total of 23 standardized tensile tests were performed on the Delta-Cast Soft(®) and 3M(TM) Scotchcast(TM) Plus Casting Tape in order to obtain mechanical properties (Young's and shear moduli and Poisson ratios). Using a radiograph of a thoracic spine, the size of twelve vertebrae and eleven intervertebral discs were measured and used to create a finite element spine model. Simulations using this model were used to establish mechanical loads which were then applied to finite element models of the TLSO and cast jacket. The thicknesses and number of material layers was varied in these models. Multiple simulations were performed.

Results: It was found that a 6.6.mm thick cast jacket made of Delta-Cast Soft(®) had a maximum deformation of 4.7 mm, a maximum stress of 2.9 MPa and a structural factor of safety of 5.71. On the other hand, a 4 mm thick jacket made of PE had a maximum deformation of 2 mm, a maximum stress of 8.9 MPa and a structural factor of safety of 2.70. The cast jacket was 3.5 times lighter and had a material of cost 1/5 of the PE brace.

Conclusions: Based on the results, either design will generate the proper constraint forces to maintain spinal correction. But, based on the design parameters (thickness, mechanical properties, structural factor of safety and cost) the brace made of cast material, though slightly thicker has superior structural and cost benefits. Thus, from the biomechanical point of view, the cast brace is more efficient than the PE brace.