Preoperative Flexibility Research Articles

Compensatory thoracic curve correction in lumbar anterior vertebral body tether (VBT) versus lumbar posterior spinal fusion (PSF).

Anterior vertebral body tethering (VBT) is a non-fusion surgical option for skeletally immature patients with idiopathic scoliosis. Prior studies demonstrated compensatory correction of the thoracic curve after lumbar posterior spinal fusion (PSF); however, no studies have examined thoracic curve correction after lumbar VBT. Patients with Lenke 5 + 6 lumbar scoliosis who underwent VBT and at least 2years' follow-up were compared to matched lumbar PSF patients. Groups were compared for major lumbar (L) and compensatory thoracic (T) curve correction, coronal/sagittal balance, and complications. 24 AVBT and 24 PSF patients were matched 1:1 for skeletal maturity and curve flexibility. There were no significant differences between VBT and PSF for average pre-operative or 2year post-operative major L or compensatory T curves. Average final L curve correction was 50% VBT and 60% PSF (p = 0.08); average T curve correction was 17% VBT and 20% PSF (p = 0.18). Compared to pre-operative flexibility radiographs, the final post-op thoracic curves were 6° (VBT) and 5° (PSF) larger. PSF had better coronal balance by average of 17mm (p < 0.0001). There were seven (24%) reoperations in the VBT group: two overcorrections relaxed, two T adding-on (extended to T by PSF-1, VBT-1), one broken tether converted to PSF. There was one (4%) reoperation in the PSF group (10-year post-op extension). Compensatory thoracic correction was achieved to a similar degree for lumbar VBT and PSF patients. There was little change in thoracic curve magnitude over time, and, on average, the correction did not reach the pre-operative flexibility curve measurement. There was better coronal balance by PSF, and a higher rate of re-operation in VBT patients. III.

Radiographic and clinical outcomes in adolescent idiopathic scoliosis corrective fusion surgery: a one-year follow-up

BACKGROUND: Adolescent idiopathic scoliosis (AIS) is a complex three-dimensional deformity of the spine, characterised by a coronal Cobb angle of at least ten degrees. The goal of surgery is not only to prevent progression, but restoration of sagittal and coronal balance, protection of cardiopulmonary function, and improvement of cosmesis. In this study, we reviewed the impact of deformity correction surgery in terms of radiology and patient-reported outcomes. METHOD: Data extracted from a prospectively maintained database (2003-2022) was retrospectively analysed for pre- and postoperative patient-reported outcome measures (PROMs), captured using the Scoliosis Research Society-22 (sRS-22) questionnaire, as well as radiological parameters. Forty-four patients with AIS were identified with pre- and postoperative PROMs. The average age at surgery was 15 years, with 84% female. There were 38% with Lenke 1 curves, and three patients had Lenke 6 curves. Posterior approach surgery was used for 73%. RESULTS: There was a total improvement in SRS-22 scores by 8%, with 75% achieving minimum clinically important difference (MCID). Patients reported significant satisfaction with treatment of 4.8 out of 5, and improvement in self-image with a change of 1.1 (p &lt; 0.05). However, no difference in function and pain were recorded (p &gt; 0.05). Overall, proximal thoracic (PT) curves improved from 24-11° (p &lt; 0.05), main thoracic (MT) curves from 55-19° (p &lt; 0.05), and thoracolumbar/lumbar (TL/L) curves from 45-11° (p &lt; 0.05). Preoperative flexibility and postoperative correction for PT curves were 40% and 41%, respectively. MT was 32% and 67%, while that for TL/L was 57% and 71%, respectively. CONCLUSION: Surgery yields significant main curve correction, which corresponds to high patient-reported satisfaction rate. Although the total SRS-22 score yielded an 8% improvement, subanalysis of self-image showed the most significant improvement of 4.5/5 (p &lt; 0.05). Level of evidence: Level 3

RADIOLOGICAL AND CLINICAL OUTCOMES IN ADOLESCENT IDIOPATHIC SCOLIOSIS CORRECTIVE FUSION SURGERY

Adolescent idiopathic scoliosis (AIS) is a complex three-dimensional deformity of the spine characterized by a Cobb angle of at least 10 degrees. The goal of surgery is to not only prevent progression but restore sagittal and coronal balance, protecting cardiopulmonary function and improving cosmesis.We reviewed the impact of deformity correction surgery in terms of radiology and patient reported outcome(PROMs).The senior authors prospectively maintained database from 2003 –2022 was retrospectively analysed in terms of pre- and post-operative patient reported outcome measures (SRS 22) as well as radiological parameters.44 patients with AIS were identified with pre and post op PROMS. The average age at surgery was 15yrs with 84% female. 38% had a Lenke 1 curve and 3 patients had Lenke 6 curves. 73% had posterior surgery.There was a total improvement in SRS 22 scores by 7.8%. Patients reported significant satisfaction with treatment 4.8/5 and improvement in self-image with a change of 0.4 (p&lt;0.001). However, no difference in function, pain and mental health were recorded.Overall, proximal thoracic (PT) curves improved from 24 degrees to 11 degrees (p&lt;0.001), Main thoracic (MT) curve 55 degrees to 19 degrees and Thoracolumbar/Lumbar curves (TL/L) 45 degreesto 11 degrees. Pre-operative flexibility and post-operative correction were 0.40 and 0.41 respectively for PT curve. MT was 0.32 and 0.67. That for TL/L was 0.57 and 0.71 respectively.Surgery yields significant main curve correction correlating with high patient reported satisfaction rate. Although total SRS 22 score yielded 7.8% improvement, sub-analysis of self-image showed the most significant improvement.

Posterior spinal fusion with lowest instrumented vertebra at L4 in idiopathic scoliosis: optimizing radiographic outcomes using pre-operative flexibility radiographs.

In idiopathic scoliosis (IS), there is general agreement ending PSFs at L3 or more cranial is preferred to optimize spinal motion, and extending PSFs to L4 may be necessary; however, this may also cause coronal imbalance or caudal disc wedging post-operatively due to leveling of L4 tilt. The purpose of this study was to identify a pre-operative radiographic measurement, which can be used to quantify the optimal amount of L4 tilt for ideal post-operative radiographic alignment. The study was a retrospective analysis of IS patients who underwent PSF to L4, with minimum 2-year follow-up post-operatively. Optimal outcome was defined by coronal balance, and L4-5 and L5-S1 disc wedging. 44 patients (84% females, mean age 13.6years) were included. Analysis of pre-operative flexibility radiographs determined only the L5 tilt on the right side-bending (RSB) radiograph correlated with optimal outcome 2 (p = 0.03). To confirm the validity, the RSB value was subtracted from the post-operative C7-L4 tilt and the odds ratio analysis which was significantly correlated with optimal outcome 1 at final follow-up (OR 1.04, 95% CI 1-1.09). In PSF to L4 for IS, L5 tilt measured from the pre-operative supine RSB radiograph can be used to optimize radiographic outcomes. Matching the pre-operative L5 tilt on RSB radiograph by leaving L4 tilted at the end of the PSF construct during surgery, quantified by the C7-L4 acute angle tilt, appears to be a useful method to achieve the desired post-operative alignment.

Do Preoperative Supine Radiographs Predict Postoperative Residual Lumbar Curvatures in Adolescent Idiopathic Scoliosis? A Retrospective Cohort Study.

Retrospective comparative study. This study compares supine vs bending flexibility radiographs and evaluates their ability to predict residual postoperative lumbar curvature after selective thoracic fusion for Lenke 1 and 2 curves across different lumbar modifiers (A, B, and C) in adolescent idiopathic scoliosis (AIS). This was a retrospective review of AIS Lenke 1 and 2 patients who underwent posterior fusion. All patients had preoperative flexibility radiographs including side-bending and supine posteroanterior (PA) films, in addition to pre- and post-operative standing PA and lateral radiographs. We used SurgiMap 2.0 software for all radiographic measurements. Pearson correlations and linear regression models were developed in SAS. A total of 86 patients were included mean age 14.9years and follow-up 72.3 months. Preoperative supine lumbar Cobb angle and preoperative side-bending Cobb angles had similar, positive correlations with postoperative lumbar Cobb angle, r = .55 (P < .001) and r = .54 (P < .001), respectively. Three regression models were built to predict postoperative lumbar Cobb angles from preoperative information: Model S (R2 = .39) uses preoperative supine lumbar curve; Model B (R2 = .44) uses preoperative side-bending lumbar curve; Model SB (R2 = .49) uses both preoperative supine and side-bending lumbar curves. Model S and B performed just as well as Model SB. Either supine or side-bending radiographs alone may be used to estimate mean residual postoperative lumbar curvature after selective posterior thoracic fusion, but little is to be gained by taking both supine and side-bending radiographs.

Correlation between supine flexibility and postoperative correction in adolescent idiopathic scoliosis

BackgroundThe preoperative flexibility of the scoliotic spine is a key aspect of surgical planning, as it provides information on the rigidity of the curve, the extent of structural changes, the levels to be fused and the amount of correction. The purpose of this study was to assess whether supine flexibility can be used to predict postoperative correction in patients with adolescent idiopathic scoliosis (AIS) by determining the correlation between these two characteristics.MethodsA total of 41 AIS patients who underwent surgical treatment between 2018 and 2020 were retrospectively enrolled for analysis. Preoperative and postoperative standing radiographs and preoperative CT images of the entire spine were collected and used to measure supine flexibility and the postoperative correction rate. T tests were used to analyse the differences in supine flexibility and postoperative correction rate between groups. Pearson’s product-moment correlation analysis was performed, and regression models were established to determine the correlation between supine flexibility and postoperative correction. Thoracic curves and lumbar curves were analysed independently.ResultsSupine flexibility was found to be significantly lower than the correction rate but showed a strong correlation with the postoperative correction rate, with r values of 0.68 for the thoracic curve group and 0.76 for the lumbar curve group. The relationship between supine flexibility and postoperative correction rate could be expressed by linear regression models.ConclusionSupine flexibility can be used to predict postoperative correction in AIS patients. In clinical practice, supine radiographs may be used in place of existing flexibility test techniques.

The Efficacy of a Posterior Approach to Surgical Correction for Neglected Idiopathic Scoliosis: A Comparative Analysis According to Health-Related Quality of Life, Pulmonary Function, Back Pain and Sexual Function

This study aimed to evaluate the treatment outcomes of severe idiopathic scoliosis (IS) and hypothesized that surgical treatment would have a superior impact on the health-related quality of life (HRQoL), pulmonary function (PF), back pain, and sexual function. We retrospectively reviewed 195 consecutive patients with IS classified into severe (SG) and moderate groups (MG) with a minimum follow-up of two years. The mean preoperative curve was 131° and 60° in the SG and MG, respectively. The mean preoperative flexibility in the bending films averaged between 22% in the SG and 41% in the MG. After definitive surgery, the main curve was corrected to 61° and 18° in the SG and MG, respectively. The mean preoperative thoracic kyphosis was 83° in the SG and 25° in the MG, which was corrected to 35° in the SG and 25° in the MG. At baseline, the percentage of predicted lung volume (FVC) was significantly lower in the SG than that in the MG (51.2% vs. 83%). The baseline percentage of the predicted FEV1 values was also significantly lower in the SG than in the MG (60.8% vs. 77%). During the two-year follow-up, the percentage of predicted FVC showed significant improvement in the SG (69.9%) (p < 0.001), and the percentage of predicted FEV1 values during the follow-up improved significantly in the SG (76.9%) (p < 0.001) compared with the MG (81%), with no statistical difference observed during the two-year follow-up. The SRS-22r showed a clinically and statistically significant improvement in the preoperative results to those of the final follow-up (p < 0.001). Surgical treatment of severe scoliosis can be safe. It provided a mean correction of the deformity for 59% of patients and significantly improved respiratory function, with the percentage of predicted forced expiratory volume in 1 s improving by 60% and the forced vital capacity improving by 50%, resulting in clinically and statistically significant improvements in the SRS-22r, HRQoL outcome scores, and back pain (reduced from 36% to 8%), as well as improved sexual function. The planned surgical treatment can achieve a very significant deformity correction with a minimal risk of complications. The surgical treatment has a superior impact on the quality of life patients with severe spinal deformities and significantly improves function in every sphere of life.

Curve Overcorrection Predicts Coronal Imbalance in Selective Thoracic Fusion in Adolescent Idiopathic Scoliosis.

Retrospective cohort Study. To identify predictive factors for coronal imbalance after selective fusion in adolescent idiopathic scoliosis (AIS) with Lenke type 1 curves. AIS patients with Lenke type 1 curve with A, B and C lumbar modifiers underwent selective thoracic fusion. The curve fulcrum flexibility and fulcrum bending correction index (FBCI) was studied. Coronal imbalance was defined as more than 2cm of truncal shift or more than 2cm list at two-year follow-up. A total of 301 patients were included in the study. Coronal imbalance at two-year follow-up was found in 38 patients (13%). At the preoperative stage, we found a significant difference in main curve flexibility with 66±15% in the balanced group and 60±15% in the imbalanced group (P = .032). At the immediate postoperative stage, mean curve correction was 71±13% vs 70±13% and mean FBCI was 112±29% vs 122±29% in the balance and unbalanced group, respectively (P = .031). Postoperative FBCI of more than 125% (third quartile) resulted in an odds ratio of 2.1 (95%CI:1.1-4.3) for coronal imbalance at two years (P=.031). No significant changes in fusion mass or LIV tilt was observed. A decreased preoperative flexibility and a higher FBCI was significantly associated with coronal imbalance. A high FBCI is an indication of a curve correction that exceeds the inherent flexibility of the spine, and our results add to a growing body of evidence that "overcorrection" of the main curve can lead to postoperative imbalance.

Scoliosis flexibility correlates with post-operative outcomes following growth friendly surgery.

The purpose of this study was to determine the relationship between pre-operative scoliosis flexibility and post-operative outcomes, including curve correction and complications, for patients who have been treated with growth friendly surgery (GFS) for early onset scoliosis (EOS). The study was conducted as a retrospective review of prospectively collected data from an international, multicenter, EOS database. EOS patients with pre-operative flexibility radiographs (traction or bending) were identified. Pre-operative flexibility and immediate post-operative correction were calculated for each patient. Post-operative complications were recorded at final follow-up. Pearson correlations were determined for flexibility vs correction for all patients and were compared between etiologies and between device types (MCGR, TGR, VEPTR). 107 patients (14 congenital, 43 neuromuscular, 31 syndromic, 19 idiopathic) with mean age 7.1years at index surgery were identified. Mean pre-operative scoliosis was 77°. Mean flexibility of 36% was not significantly different between etiologies. Mean immediate post-operative scoliosis was 46° (p < 0.001 vs. pre-operative) with mean correction of 38%. Correction rate was not significantly different between etiologies; however, correction rate was different between device types (MCGR 45%, TGR 40%, VEPTR 14%; p = < 0.001). Pearson correlation for flexibility vs correction was fair (r = 0.37, p < 0.001). This correlation was observed for idiopathic (r = 0.53, p = 0.020) and neuromuscular (r = 0.46, p = 0.0020) scoliosis, but not for congenital or syndromic scoliosis. At a mean of 6.1year follow-up (minimum 2years to 15.5years), 60 of 81patients (74%) experienced at least one complication. Odds ratio for developing a complication was 3.00 (1.03-8.76) for patients with pre-operative flexibility < 45% (p < 0.05). As lower pre-operative flexibility was associated with less scoliosis correction and with a higher risk of post-operative complications, curve flexibility should be considered when deciding upon the timing of growth friendly surgery. Level III-retrospective comparative study.

Predicting the impact of intraoperative halo-femoral traction from preoperative imaging in neuromuscular scoliosis.

Intraoperative traction (ITx) has been demonstrated to be a useful adjunct intervention at the time of posterior spinal fusion (PSF) for the treatment of severe neuromuscular scoliosis (NMS) to improve the coronal spinal deformity and pelvic obliquity. The purpose of this study is to determine if preoperative flexibility radiographs can predict the amount of spinal deformity and pelvic obliquity correction at final follow-up. This was a retrospective analysis of a single-surgeon series who underwent PSF to the pelvis with adjunct ITx for NMS. Database query identified 76 NMS patients, of which 41 met inclusion criteria. Demographic, radiographic and operative data were analyzed. Of the 41 study patients, 56% (n = 23) were male and mean age at surgery was 13.6years. Mean follow-up of 4.1years (minimum follow-up 2years). 35 patients had cerebral palsy, 5 patients were syndromic, and 1 patient had myelomeningocele. The average preoperative weight was 35kg and all were wheelchair ambulators. Total traction applied on average was 49% of the preoperative body weight. Mean preoperative coronal deformity was 91° which improved to 43° at final follow-up (53% correction). Push-supine imaging had the strongest correlation to major coronal deformity outcome at final follow-up (r2 = 0.87, p ≤ 0.0001). Compared to push-supine imaging, there was a mean greater coronal deformity correction of 18 ± 10° (p ≤ 0.0001) at final follow-up. To predict the final coronal deformity, the regression equation was final Cobb angle = 1.13085 + preop push-supine Cobb angle × 0.68830. Mean preoperative pelvic obliquity was 34° which improved to 12° at final follow-up (65% correction). Push-supine imaging had the strongest correlation to pelvic obliquity outcome at final follow-up (r2 = 0.59, p = 0.0001). Compared to push-supine imaging, there was a mean greater pelvic obliquity correction of 3 ± 10° (p = 0.0857) at final follow-up. The regression equation was final POB = 6.42096 + preop push-supine POB × 0.36675. Mean preoperative kyphosis was 70° and 52° at final follow-up (26% correction). The results of this study demonstrated for preoperative planning that the push-supine flexibility radiograph is most predictive of the coronal deformity and of the pelvic obliquity correction. At final follow-up in this NMS population, there was a mean greater improvement of 18° for coronal deformity versus preoperative push-supine imaging and 3° for pelvic obliquity versus preoperative push-supine imaging. At the time of PSF, ITx is an effective adjunct technique to improve coronal deformity and POB for NMS producing 53% coronal correction, 65% POB correction, and 26% kyphosis correction. IV.

Long-term outcome after surgical treatment of Scheuermann's Kyphosis (SK).

A retrospective observational cohort study with a minimum follow-up of 10years of patients who underwent surgery for Scheurmann Kyphosis (SK). Evaluate the long-term clinical and radiological outcome of patients with SK who either underwent combined anterior-posterior surgery or posterior instrumented fusion alone. There is paucity of literature for long-term outcome studies on SK. The current trend is towards only posterior (PSF) surgical correction for SK. The combined strategy of anterior release, fusion and posterior spinal fusion (AF/PSF) for kyphosis correction has become historic relic. Long-term outcome studies comparing the two procedures are lacking in literature. 51 patients (30M: 21F) who underwent surgery for SK at a single centre were reviewed. Nineteen had posterior instrumentation alone (PSF) (Group 1) and 32 underwent combined anterior release, fusion with posterior instrumentation (AF/PSF) (Group 2). The clinical data included age at surgery, gender, flexibility of spine, instrumented spinal levels, use of cages and morcellised rib grafts (in cases where anterior release was done), posterior osteotomies and instrumentation, complications and indications for revision surgery. Preoperative flexibility was determined by hyperextension radiographs. The radiological indices were evaluated in the pre-operative, 2-year post-operative and final follow-up [Thoracic Kyphosis (TK), Lumbar lordosis (LL), Voustinas index (VI), Sacral inclination (SI) and Sagittal vertical axis (SVA)]. The loss of correction and incidence of JK (Junctional Kyphosis) and its relation to fusion levels were assessed. Complications and difference in outcome between the two groups were analyzed. The mean age at surgery for 51 patients was 20.6years who were followed up for a minimum of 10years (mean: 14years; range 10-16years). The mean age was 18.5 ± 2.2years and 21.9 ± 4.8years in groups 1 and 2, respectively. The mean pre- and 2-year post-operative ODIs were 32.6 ± 12.8 and 8.4 ± 5.4, respectively, in group 1 (p < 0.0001) and 30.7 ± 11.7 and 6.4 ± 5.7, respectively, in group 2 (p < 0.0001). The final SRS-22 scores in group 1 and 2 were 4.1 ± 0.4 and 4.0 ± 0.35, respectively (p = 0.88). The preoperative flexibility index was 49.2 ± 4.2 and 43 ± 5.6 in groups 1 and 2, respectively (p < 0.0001). The mean TKs were 81.4° ± 3.8° and 86.1° ± 6.0° for groups 1 and 2, respectively, which corrected to 45.1° ± 2.6° and 47.3° ± 4.8°, respectively, at final follow-up (p < 0.0001). The mean pre-operative LL angle was 60.0° ± 5.0° and 62.4° ± 7.6° in groups 1 and 2, respectively, which at final follow-up was 45.1° ± 4.4° and 48.1° ± 4.8°, respectively (p < 0.0001). The mean pre-operative and final follow-up Voustinas index (VI) in group 1 were 22.9 ± 2.9 and 11.2 ± 1.2, respectively, and in group 2 was 25.9 ± 3.5 and 14.0 ± 2.3, respectively. The mean pre-operative and final follow-up SI angle were 43.6° ± 3.3° and 31.2° ± 2.5° in group 1, respectively, and 44.3° ± 3.5° and 32.1° ± 3.5° in group 2, respectively (p < 0.0001). The pre-operative and final follow-up SVA in group 1 were -3.3 ± 1.0 cms and -1.3 ± 0.5 cms, respectively, and in group 2 was -4.0 ± 1.3cms and -1.9 ± 1.1cms, respectively (p < 0.0001). Though the magnitude of curve correction in the groups 1 and 2 was significant 36° vs 39° (p = 0.05), there was no significant difference in correction between the two groups. Proximal JK was seen in seven and distal JK in five patients were observed in the whole cohort. The long-term clinical outcomes for both PSF and AF/PSF are comparable with reproducible results. No difference was noted in loss of correction and outcome scores between the two groups. The correction of thoracic kyphosis (TK) had a good correlation with ODI. AF/PSF had much higher complications than PSF group. The objective of correcting the sagittal profile and balancing the whole spinal segment on the pelvis can be achieved through single posterior approach with fewer complications.

An intraoperative laterally placed distractor for gradual load sharing correction of severe spastic neuromuscular spinal deformity.

To analyze the overall deformity correction for severe neuromuscular scoliosis using laterally placed intra-operative distraction and compare to those receiving standard surgical technique. This was a retrospective, IRB-approved, cohort study of patients with GMFCS 4 or 5 spastic cerebral palsy with neuromuscular scoliosis, age greater than 10years, who underwent posterior spinal fusion from 2007 to 2019. All patients had vectored cervical traction with Gardner-Wells tongs, with hips flexed in a relative sitting position. The study cohort underwent intraoperative, laterally placed correction using a distractor placed between two upper ribs and the ipsilateral greater trochanter while the control cohort did not. The 24 study patients were compared to 22 control patients. Preoperative comparisons identified significant differences in Cobb angle, preoperative flexibility, and pelvic obliquity with the study group having larger, stiffer deformities with greater obliquity. There were no differences in pre-operative sagittal plane deformity. Mean post-operative upright Cobb angle correction was 67.3° ± 14.8° in the study and 55.3° ± 9.9° in the control group, representing a 66% and 60% correction, respectively. No neurological or other complications were noted from the use of this technique. The use of a laterally placed distraction device from upper ribs to ipsilateral greater trochanter allowed gradual lateral un-bending of large stiff neuromuscular spine deformities with greater correction than that of standard technique. In this small series, the technique allowed load-sharing during correction, with hips remaining in a functional sitting position, and without neurological complications. Level III-retrospective cohort study.

Does preoperative and intraoperative imaging for anterior vertebral body tethering predict postoperative correction?

Anterior vertebral body tethering (AVBT) is an emerging approach for idiopathic scoliosis. However, overcorrection and under-correction are common causes of revision surgery, and intraoperative tensioning of the cord is one key component to achieve appropriate curve correction. We sought to determine whether preoperative flexibility radiographs or intraoperative radiographs would predict correction at first erect imaging for scoliosis patients undergoing anterior vertebral body tethering (AVBT). Single-center retrospective review. Fifty-one patients with a diagnosis of idiopathic scoliosis underwent anterior body tethering. Preoperative flexibility films and intraoperative radiographs were compared to first erect standing radiographs to determine if there was a correlation in Cobb angle. Preoperative major Cobb angle measured 52° ± 9°. Major Cobb angle on bending films was 24° ± 8°. Intraoperative imaging showed correction to a mean of 17° ± 8°. Postoperative first erect standing radiographs showed correction to a mean of 26° ± 10°. The mean difference in major Cobb angle between intraoperative radiograph and a first erect radiograph was 10° ± 4°, whereas the mean difference from preoperative bending radiograph at first erect was 2° ± 7°. Thus, correction on preoperative flexibility films correlated with the first erect radiograph. Preoperative bending radiographs provide a reasonable estimate of postoperative correction for patients undergoing AVBT with tensioning of the cord. Surgeons should expect the major Cobb angle to increase on first erect radiographs compared to intraoperative radiographs. These findings may guide patient selection and assist surgeons in achieving appropriate correction intraoperatively.

Minimum 5-year follow-up outcomes for one-stage posterior instrumentation without neurosurgery intervention for correction of scoliosis associated with Chiari I malformation and syringomyelia.

Traditionally, the common belief has been that, all patients with Chiari I malformation (CM-1) and syringomyelia (SM) undergoing a neurosurgical procedure even if they are neurologically asymptomatic. As the pathology of CM-1 and SM has become better understood, the traditional concepts have been challenged. The objective of this study was to investigate the minimum 5-year follow-up clinical outcomes of surgical treatment of patients with scoliosis associated with CM-1 and SM and to evaluate the necessity of neurosurgical intervention before corrective surgery. This retrospective study was performed from May 2009 to September 2014. We enrolled 35 patients with scoliosis associated with CM-1 and SM who were undergoing spinal correction surgery without neurosurgical intervention. During the surgery, spinal cord monitor and wake-up test were used. Preoperative, postoperative, and final follow-up major curve coronary Cobb angle, correction rate, apical vertebral rotation (AVR), apical vertebral translation (AVT), thoracic kyphosis angle (T5-T12), lumbar lordosis angle (L1-S1) were analyzed on radiographs. The mean follow-up period was 82.5months. The preoperative and postoperative mean curve coronary Cobb angle was from 55.7 ± 7.5° to 20.1 ± 5.8°, correction rate was 63.9%, AVR from 2.8 ± 0.6° to 1.3 ± 0.5°, AVT from 5.1 ± 1.4 to 1.7 ± 0.7cm, thoracic kyphosis angle from 18.7 ± 4.0° to 32.2 ± 2.7°, lumbar lordosis angle from 36.3 ± 4.1° to 43.8 ± 3.2°. No neurological deficits occurred during the operation and follow-up. Our minimum 5-year follow-up outcomes showed that in a distinct patient population of neurologically asymptomatic individuals with CM-1, SM and progressive scoliosis, posterior instrumented spinal deformity surgery can be safely done without neurosurgical interverventions with the help of preoperative flexibility evaluation and intraoperative neuromonitoring.

Proximal junctional fracture and kyphosis after long spinopelvic corrective fixation for adult spinal deformity

BackgroundProximal junctional fractures (PJFx) are the main cause for proximal junctional kyphosis (PJK), a complication of adult spinal deformity surgery. This study investigated risk factors for PJFx when performing long spinopelvic corrective fixation with lateral interbody fusion from T9 to ilium. MethodsThis was a retrospective study of 43 patients with a minimum follow-up of 2 years. Radiographic measurements including thoracic kyphosis (TK), sagittal vertical axis (SVA), T1 pelvic angle (TPA), proximal junctional angle (PJA), lumbar lordosis (LL), lower LL, and pelvic tilt were measured preoperatively, one-month postoperatively, and at final follow up. TK and LL were also measured in a fulcrum backward-bending position preoperatively. ResultsAt final follow-up, PJK was found in 30/43 patients (69.8%); 20.9% of the cases had PJFx (9 patients). TPA (preoperative, and one-month postoperative) was significantly higher in the PJFx group than in the other groups. The differences in TPA, TK, and PJA between preoperative and one-month postoperative measurements in the PJFx group were significantly higher than those in the other groups. At final follow up, SVA was significantly higher in the PJFx group than in the “PJK without PJFx” group. TPA and TK were significantly higher in the PJFx group than in the other groups. PJA was significantly different between all groups. ConclusionPreoperative large TPA was the only risk factor for PJFx. Preoperative flexibility of the thoracolumbar spine and overcorrection of sagittal deformity were not related to PJFx or PJK.

320. Effect of supine alignment on postoperative sagittal alignment following ASD surgery

BACKGROUND CONTEXT Several guidelines for target-selection in the literature utilize pelvic incidence (PI) as a marker for lumbar correction. In practice, postoperative alignment is highly affected by preoperative data, including demographics and spinal flexibility. Preoperative supine radiographs allow for early visualization of patient alignment in the intraoperative position. Our objective was to determine the strongest predictor of postoperative alignment among PI, age and preoperative supine alignment using a retrospective, single center database of adult spinal deformity (ASD) patients. PURPOSE Identify independent predictors of postoperative curvatures (LL and TK) using preoperative data only. STUDY DESIGN/SETTING Retrospective review of a single-center database of ASD patients. PATIENT SAMPLE A total of 99 surgically treated ASD patients with minimum 1 year follow-up. OUTCOME MEASURES L1-S1 lordosis, T4-T12 kyphosis. METHODS Pre- to postoperative analysis was conducted using paired t-test sampling. Patients were stratified by region of fusion postoperative: complete lumbar fusion (from L1 to S1) and/or complete thoracic fusion (from T4 to T12). Pearson's r correlation analysis was performed on postoperative curvatures (LL and TK) with preoperative alignment in both standing and supine positions. Correlation analysis was repeated for LL in patients with complete lumbar fusion and for TK in patients with complete thoracic fusion. Lastly, a multilinear stepwise regression was conducted to identify independent predictors of LL or TK post-op. RESULTS A total of 99 patients were included in the analysis (63.2yo, 83.1%F, 27.3kg/m2, mean f/u 21 months±.9.8). Preoperative SRS classification demonstrated a moderate to severe sagittal and/or coronal deformity (PT modifier: 18.2% ++, SVA: 27.3% ++, PI-LL: 29.3% ++, SRS type: 29.3% N and 68.7% L or D). Sagittal alignment significantly improved between pre- and postoperative (all p CONCLUSIONS Preoperative supine alignment is one of the best predictors of postoperative alignment at 1 year. When controlling for fusion location, results show an even greater importance of supine alignment, especially regarding thoracic alignment. Specific attention is required when performing thoracic fusion to avoid thoracic flattening FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

297. Preoperative extension lateral cervical radiographs are associated with osteotomy type, approach and postoperative cervical alignment following cervical deformity surgery

BACKGROUND CONTEXT Choosing the surgical approach and osteotomy type is challenging when surgically treating cervical deformity. Preoperative assessment of flexibility and final alignment would be useful for surgeons treating this complex problem. Currently extension lateral XR are inconstantly taken for the management of cervical deformity for planning purposes. PURPOSE Investigate the relationship of surgical procedure choice and the pre-operative flexibility of the cervical spine. Determine if extension lateral XR (ELXR) can also predict the final postoperative alignment. STUDY DESIGN/SETTING Retrospective review of prospective, consecutively enrolled multicenter cervical deformity database PATIENT SAMPLE A total of 106 cervical deformity patients OUTCOME MEASURES Surgical treatment, radiographic alignment parameters (SS, T1S-CL, cSVA, C2 slope, T1 slope) METHODS A prospective database of operative cervical deformity patients was analyzed. Inclusion was cervical kyphosis>10°, cervical scoliosis>10°, C2-C7 SVA>4cm or chin-brow vertical angle>25°. Patients were excluded if they did not have neutral and ELXR or did not have deformity limited to the cervical or cervicothoracic spine. The ELXR was compared to preoperative neutral lateral, and 3 mo alignment XR and type of surgical osteotomy based upon the Ames Classification. Statistical analysis included t-test and chi-squared. RESULTS A total of 106 from 164 patients met the inclusion criteria. Mean age of 60 yo, with 58% females. Of the study population, 43.4% of patients had prior cervical surgery. The evaluation of ELXR in patients who received grade 1-2 osteotomies (as compared to those who received grade 5,6 or 7), shows they have statistically lower T1S (23.06 vs 35.46; p=.021), lower T1S-CL (20.90 vs 36.29; p=.033), lower cSVA (24.66 vs 48.35; p 17 in the ELXR (46.77% vs 36.36%; p=.033). Overall, while surgery created a significant change in all radiographic parameters; the 3 month lateral XR and baseline ELXR were statistically similar for T1S-CL (26.04 vs 24.83; p=.542) and C2Slope (23.27 vs 22.87; p=.839). CONCLUSIONS Preoperative ELXR had a significant association with surgical approach and grade of osteotomy. The ELXR was statistically similar to the post-operative 3-month lateral XR and should be used to predict final cervical alignment. Obtaining ELXR is a critical alignment tool, and should be obtained as a part of the preoperative surgical plan. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Use of Magnetic Spinal Growth Rods (MCGR) With and Without Preoperative Halo-gravity Traction (HGT) for the Treatment of Severe Early-onset Scoliosis (EOS).

Correction of severe scoliosis through distraction-based techniques poses a challenge. Magnetically controlled growing rod (MCGR) hardware complications are common with a 27.8% to 46.7% revision rate in under 2 years. Loss of correction and diminishing returns are the norm. Treatment of severe scoliosis with halo-gravity traction (HGT) before MCGR has not been previously reported. The purpose of this study was to assess initial correction, maintenance of correction, and complication rate in patients with severe scoliosis treated with and without HGT before MCGR. IRB-approved retrospective single site cohort study of a prospectively collected database. Forty-two patients underwent MCGR between 2014 and 2017 at a single site, 12 with prior growing constructs were excluded, 30 patients were included, 12 patients underwent preoperative HGT. Charts were reviewed for demographic, clinical, and radiographic information. The HGT group had larger major curves averaging 90 (69 to 114) degrees versus 77 (56 to 113) degrees in the non-HGT group P=0.018. Percent correction on preoperative flexibility films were 17% versus 40% for those in the HGT versus non-HGT group, P=0.000. An additional 22% correction of the curve magnitude occurred between the flexibility and in-traction films representing 43% of the total correction achieved, P=0.000, was achieved. EBL, and postoperative major curve and major curve correction were not significant. Thirteen percent of patients experienced complications. Average follow-up was 712 versus 561 days in the HGT versus non-HGT groups. Large, rigid curves can achieve equivalent correction to flexible curves with HGT. Forty-three percent of the total correction achieved occurred during traction. Thirty percent of the total correction occurred at implantation of the MCGR in the HGT group versus 28% in the non-HGT group. At most recent follow-up HGT patients had statistically maintained their major curve correction better than non-HGT patients. Level III-therapeutic study.

Assessment of Change of Shoulder Balance in Patients with Adolescent Idiopathic Scoliosis after Correctional Surgery.

To identify factors that influence shoulder balance and to determine whether a model can be made to predict shoulder balance after corrective surgery. This is a retrospective study in which we examined the records of with adolescent idiopathic scoliosis (AIS) patients who underwent single posterior spinal correction and fusion using all pedicle screws with derotation in our institution between January 2008 and June 2010. For the radiographic outcome measurement, we measured the preoperative lumbar curve, the main thoracic curve, and their difference (L_TH_D), and the degree of correction of the lumbar curve, the main thoracic curve, and their difference (c_L_TH_D) to evaluate their influence on postoperative shoulder balance. The preoperative flexibility of the proximal non-fusion curve on the immediate postoperative tilt of the upper endplate of the uppermost vertebra of fusion segments (Up_FuS) was used to evaluate and predict the shoulder balance at follow-up. For patients who had shoulder balance at follow-up, the average balance time was 7.1 months, and in most of them, balance was detected within 12 months. The main thoracic curve has the greatest influence on preoperative shoulder tilt and correction of the main thoracic curve has the greatest influence on the postoperative alteration in shoulder balance. To evaluate the influence on the preoperative shoulder tilt, the lumbar curve must be larger than the main thoracic curve both pre operatively and postoperatively. If the preoperative flexibility of the proximal non-fusion curve on the immediate postoperative Up_FuS includes the horizontal line (With Horizontal group), shoulder balance can be ensured. The postoperative Up_FuS can be evaluated based on the preoperative Up_FuS and the degree of correction of the lumbar and main thoracic curves. Shoulder balance can be ensured in patients in the With Horizontal group after surgery. If the preoperative Up_FuS and the degree of correction of the main thoracic curve and the lumbar curve are considered in the preoperative plan, the desired postoperative Up_FuS can be achieved, ensuring shoulder balance at follow-up.

Do Pedicle Screws in Concave Apex of Scoliosis Offer Any Advantages?

Study Design Retrospective analysis of prospectively collected data.Purpose To assess the relative advantages of implant constructs with and without pedicle screws in the concave apex for correcting scoliosis.Overview of Literature Concave apical pedicles in scoliosis can be narrow and dysplastic. Neural structures also migrate toward concavity, leaving little room for error while inserting pedicle screws into the concave apex.Methods Patients (n=35) undergoing scoliosis surgery from September 2004 to September 2009 with minimum 5-year follow-up period were included. Exclusion criteria were pseudarthrosis, implant failure, infection, anterior release surgery, corrective osteotomies, incomplete data, constructs not involving anchors at the apex of the curve, and kyphoscoliosis. Curves were classified into two groups as follows: group A, with screws alone anchoring the convex apex and the correction performed from the convex side and group B, with screws anchoring the concave apex with or without convex apex purchase and the correction performed from the concave side.Results Twenty-two of 35 patients were selected. In these patients, 29 individual curves were selected and classified into groups A (n=15) and B (n=14). Both groups were comparable in terms of age, sex, and etiology (idiopathic and nonidiopathic). However, group A had larger (68.53°±26.29°) and more rigid (29.04%±18.22% flexibility) curves than group B (50.14°±16.89° with 49.87%±25.01% flexibility) (two-tailed p <0.05). Despite this, the immediate postoperative correction was comparable between the two groups (A, 57.98%±16.28%; B, 62.76%±13.13%; two-tailed p =0.39). Interestingly, group A showed significantly better results in terms of the gain of instrumented correction over and above preoperative flexibility (A, 28.94%±8.51%; B, 12.89%±23.06%; two-tailed p =0.03). There was no statistically significant difference in the correction percentage of sagittal profile between the two groups and in the loss of correction at follow-up or Scoliosis Research Society-22 scores.Conclusions Present study could not demonstrate any advantages associated with use of apical concave pedicle screws.