Preoperative Pelvic Obliquity Research Articles

Pelvic Fixation Technique Using the Ilio-Sacral Screw for 173 Neuromuscular Scoliosis Patients.

Pelvic fixation remains one of the main challenging issues in non-ambulatory neuromuscular scoliosis (NMS) patients, between clinical effectiveness and a high complication rate. The objective of this multicenter and retrospective study was to evaluate the outcomes of a technique that was applied to treat 173 NMS patients. The technique is not well-known but promising; it uses the ilio-sacral screw, combined with either the posterior spinal fusion or fusionless bipolar technique, with a minimum follow-up of two years. The mean operative age of the patients was 13 ± 7 years. The mean preoperative main coronal curve was 64° and improved by a mean of -39° postoperatively. The mean preoperative pelvic obliquity was 23°, which improved by a mean of -14° postoperatively. No decrease in the frontal or sagittal correction was observed during the last follow-up. The sitting posture improved in all cases. Twenty-nine patients (17%) had a postoperative infection: twenty-six were treated with local debridement and antibiotics, and three required hardware removal. Fourteen mechanical complications (8%) occurred: screw malposition (n = 6), skin prominence (n = 1), and connector failure (n = 1). This type of surgery is associated with a high risk for infection. Comorbidities, rather than the surgery itself, were the main risk factors that led to complications. The ilio-sacral screw was reliable and effective in correcting pelvic obliquity in NMS patients. The introduction of intraoperative navigation should minimize the risk of screw misplacement and facilitate revision or primary fixation.

Bipolar Fusionless Versus Standard Fusion Surgery in Neuromuscular Scoliosis: A Two-center Comparative Study.

Nonrandomized controlled cohort. To compare early results between bipolar fusionless construct (BFC) and single posterior fusion (SPF) surgery in neuromuscular scoliosis (NMS). Surgical treatments for NMS have traditionally been characterized by high complication rates. A mini-invasive BFC was developed to reduce these risks while maintaining adequate curve reduction. There is, however, a current lack of studies comparing clinical and radiologic perioperative outcomes between both techniques. All patients surgically treated for NMS with to-pelvis construct between 2011 and 2021 at 2 centers were included and divided into 2 groups according to the surgical technique (BFC or SPF). Gender, age, main deformity region, etiology, preoperative and postoperative main curve magnitude and pelvic obliquity, surgery time, estimated blood loss and transfusion rates, length of hospital stay, the magnitude of main curve and pelvic obliquity correction, and early complications were compared. Quantitative data were compared through ANOVA or Mann-Whitney test. Analysis of qualitative outcomes was performed through Fisher exact test and logistic regressions. Kruskal-Wallis test was used to compare complications between groups. Eighty-nine NMS patients were included: 48 in the SPF group and 41 in the BFC group. Surgery time (203 vs. 241min), rate (32 vs. 52%) and severity of complications, unplanned returns to the operating room (15 vs. 39%), estimated blood loss (179 vs. 364 cc), and transfusion rates (27 vs. 73%) were lower in the BFC group ( P <0.05). There were no significant differences in age, maturity stage, preoperative curve magnitude, preoperative pelvic obliquity and postoperative curve, and pelvic obliquity correction between groups. BFC may be a safer and less invasive option for NMS surgical treatment, resulting in similar curve corrections while significantly decreasing the number and severity of complications as well as intraoperative blood loss when compared with SPF. Level -lll.

Distal fusion in Duchenne scoliosis: the relevance of preoperative pelvic obliquity. A case series study.

The aim of this study was to determine clinical and radiographic outcomes for Duchenne Muscular Dystrophy (DMD) patients who underwent posterior spinal fusion from T2/3 to L5 (without pelvic fixation), at this single centre. From January 2012 to January 2020, 29 consecutive DMD scoliosis patients underwent posterior spinal fusion using pedicle screws from T2/3 to L5 in a single center with a minimum of 3years follow-up (FU). Radiologic measurements and chart review were performed. Twenty nine patients aged 14 ± 1.5years were included. No patient was lost to FU. All patients had significant correction in Cobb angle, pelvic obliquity (PO) and lumbar lordosis (LL), without loss of correction at last FU. The mean values for preoperative, immediate postoperative and last FU were CA 62o, 15o and 17o, PO: 21o, 8o and 9o; and LL 10o, -41o and -41o respectively. Correction in CA was independent of any variable analysed including implant density, rod diameter, traction, or bone density. Regarding PO, it was inversely related to age and independent of all other variables. Factors associated with postoperative complications were age and respiratory function. It appears from our results that pelvic fixation might not always be required in DMD scoliosis surgery, when using pedicle screws with lowest instrumented vertebra at L5. However, larger preoperative PO values can be related with residual PO. It seems that probably related to the underlying condition, early surgery may decrease incidence of complications. IV.

Impact of the hip-spine relationship and patient-perceived leg length discrepancy after total hip arthroplasty: A retrospective study

PurposePatient-perceived leg length discrepancy (PLLD) is one of the major postoperative complications of total hip arthroplasty (THA). This study aimed to identify factors that cause PLLD following THA. Materials and methodsThis retrospective study included a series of consecutive patients who underwent unilateral THA between 2015 and 2020. Ninety-five patients who underwent unilateral THA with postoperative radiographic leg length discrepancy (RLLD) ≤1 cm were classified into two groups according to the direction of preoperative pelvic obliquity (PO). Standing radiographs of the hip joint and whole spine were obtained before and one year after THA. The clinical outcomes and the presence or absence of PLLD was confirmed one year after THA. ResultsSixty-nine patients were classified as having type 1 PO (rising toward the unaffected side) and 26 were classified as having type 2 PO (rising toward the affected side). Eight patients with type 1 PO and seven with type 2 PO had PLLD postoperatively. In the type 1 group, patients with PLLD had larger preoperative and postoperative PO values and larger preoperative and postoperative RLLD than those without PLLD (p = 0.01, p < 0.001, p = 0.01, and p = 0.007, respectively). In the type 2 group, patients with PLLD had larger preoperative RLLD, larger amount of leg correction, and a larger preoperative L1-L5 angle than those without PLLD (p = 0.03, p = 0.03, and p = 0.03, respectively). In type 1, postoperative PO was significantly associated with postoperative PLLD (p = 0.005), but spinal alignment was not an indicator of postoperative PLLD. The area under the curve (AUC) for postoperative PO was 0.883 (good accuracy) with a cut-off value was 1.90° ConclusionRigidity of the lumbar spine might lead to postoperative PO as a compensatory movement, resulting in PLLD after THA in type 1. Further research on the relationship between flexibility of the lumbar spine and PLLD is needed.

When to Perform Fusion Short of the Pelvis in Patients with Cerebral Palsy?: Indications and Outcomes.

Using 2 prospective databases, we analyzed 87 pediatric patients who underwent PSF short of the pelvis from 2008 to 2015 to treat CP-related scoliosis and who had ≥2 years of follow-up. Preoperative radiographic and clinical variables were analyzed for associations with unsatisfactory correction (defined as pelvic obliquity of ≥10°, distal implant dislodgement, and/or reoperation for increasing deformity at 2- or 5-year follow-up). Continuous variables were dichotomized using the Youden index, and a multivariable model of predictors of unsatisfactory correction was created using backward stepwise selection. Finally, radiographic, health-related quality-of-life, and clinical outcomes of patients with fusion short of the pelvis who had neither of the 2 factors associated with unsatisfactory outcomes were compared with those of 2 matched-control groups. Deformity correction was unsatisfactory in 29 of 87 patients with fusion short of the pelvis. The final model included preoperative pelvic obliquity of ≥17° (odds ratio [OR], 6.8; 95% confidence interval [CI], 2.3 to 19.7; p < 0.01) and dependent sitting status (OR, 3.2; 95% CI, 1.1 to 9.9; p = 0.04) as predictors of unsatisfactory correction. The predicted probability of unsatisfactory correction increased from 10% when neither of these factors was present to a predicated probability of 27% to 44% when 1 was present and to 72% when both were present. Among matched patients with these factors who had fusion to the pelvis, there was no association with unsatisfactory correction. Patients with independent sitting status and pelvic obliquity of <17° who had fusion short of the pelvis had significantly lower blood loss and hospital length of stay, and better 2-year health-related quality-of-life scores compared with matched controls with fusion to the pelvis. In patients with scoliosis secondary to CP, pelvic obliquity of <17° and independent sitting status are associated with a low risk of unsatisfactory correction and better 2-year outcomes when fusion short of the pelvis is performed. These may be used as preoperative criteria to guide the decision of whether to perform fusion short of the pelvis in patients with CP. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Hip Displacement Does Not Change After Pelvic Obliquity Correction During Spinal Fusion in Children With Cerebral Palsy.

Children with cerebral palsy (CP) frequently develop both neuromuscular hip dysplasia and scoliosis, and occasionally, the timing of the worsening of both of these pathologies is concurrent. The question as to whether the hip or spine should be addressed first in CP remains controversial, with the majority of evidence being "expert opinion." The purpose of this project was to determine the impact of posterior spinal fusion (PSF) on the change in hip displacement for children with CP without previous reconstructive hip surgery. This was an Institutional Review Board-approved study that observed 67 patients from 2004 to 2018. Inclusion criteria included children with CP, 18 years of age and younger, Gross Motor Function Classification System IV and V, undergoing PSF at a single tertiary care children's hospital with a minimum 2-year follow-up. The primary outcome was the change in hip displacement as quantified by the migration percentage (MP). The hip with the highest MP (worst hip) at the spine preoperative analysis were included for analysis. Triradiate cartilage (TRC) status and pelvic obliquity correction were analyzed with multivariate analysis. Sixty-seven patients were included for analysis, with a mean age of 12.5±2.3 years. The mean major curve angle of the major curve was 77±23 degrees and the mean preoperative pelvic obliquity was 21±12 degrees. There was no statistically significant change in MP after PSF from a mean preoperative value of 41±27%, to a mean postoperative value of 41±29% at the last follow-up, (P=0.76) The mean follow-up time was 4.1±2.7 years. TRC status (P=0.52) and the severity of pelvic obliquity (P=0.10) did not statistically impact the change in MP after PSF. PSF did not influence-either negatively or positively-the progression of hip displacement in children with CP, regardless of pelvic obliquity correction or TRC status. The lack of deterioration in hip displacement post-PSF, however, may suggest a protective effect of spine surgery. Level III-retrospective cohort study.

Understanding the role of pelvic obliquity and leg length discrepancy in adult spinal deformity patients with coronal malalignment: unlocking the black box.

This study had 3 objectives: 1) to describe pelvic obliquity (PO) and leg-length discrepancy (LLD) and their relationship with coronal malalignment (CM); 2) to report rates of isolated PO and PO secondary to LLD; and 3) to assess the importance of preoperative PO and LLD in postoperative complications, readmission, reoperation, and patient-reported outcomes. Patients undergoing surgery (≥ 6-level fusions) for adult spinal deformity at a single institution were reviewed. Variables evaluated were as follows: 1) PO, angle between the horizontal plane and a line touching bilateral iliac crests; and 2) LLD, distance from the head to the tibial plafond. Coronal vertical axis (CVA) and sagittal vertical axis measurements were collected, both from C7. The cutoff for CM was CVA > 3 cm. The Oswestry Disability Index (ODI) was collected preoperatively and at 2 years. Of 242 patients undergoing surgery for adult spinal deformity, 90 (37.0%) had preoperative CM. Patients with preoperative CM had a higher PO (2.8° ± 3.2° vs 2.0° ± 1.7°, p = 0.013), a higher percentage of patients with PO > 3° (35.6% vs 23.5%, p = 0.044), and higher a percentage of patients with LLD > 1 cm (21.1% vs 9.8%, p = 0.014). Whereas preoperative PO was significantly positively correlated with CVA (r = 0.26, p < 0.001) and maximum Cobb angle (r = 0.30, p < 0.001), preoperative LLD was only significantly correlated with CVA (r = 0.14, p = 0.035). A total of 12.2% of patients with CM had significant PO and LLD, defined as follows: PO ≥ 3°; LLD ≥ 1 cm. Postoperatively, preoperative PO was significantly associated with both postoperative CM (OR 1.22, 95% CI 1.05-1.40, p = 0.008) and postoperative CVA (β = 0.14, 95% CI 0.06-0.22, p < 0.001). A higher preoperative PO was independently associated with postoperative complications after multivariate logistic regression (OR 1.24, 95% CI 1.05-1.45, p = 0.010); however, 2-year ODI scores were not. Preoperative LLD had no significant relationship with postoperative CM, CVA, ODI, or complications. A PO ≥ 3° or LLD ≥ 1 cm was seen in 44.1% of patients with preoperative CM and in 23.5% of patients with normal coronal alignment. Preoperative PO was significantly associated with preoperative CVA and maximum Cobb angle, whereas preoperative LLD was only associated with preoperative CVA. The direction of PO and LLD showed no consistent pattern with CVA. Preoperative PO was independently associated with complications but not with 2-year ODI scores.

Incidence and risk factors of iatrogenic coronal malalignment after adult spinal deformity surgery: a single-center experience.

The authors' objectives were: 1) to evaluate the incidence and risk factors of iatrogenic coronal malalignment (CM), and 2) to assess the outcomes of patients with all three types of postoperative CM (iatrogenic vs unchanged/worsened vs improved but persistent). A single-institution, retrospective cohort study was performed on adult spinal deformity (ASD) patients who underwent > 6-level fusion from 2015 to 2019. Iatrogenic CM was defined as immediate postoperative C7 coronal vertical axis (CVA) ≥ 3 cm in patients with preoperative CVA < 3 cm. Additional subcategories of postoperative CM were unchanged/worsened CM, which was defined as immediate postoperative CVA within 0.5 cm of or worse than preoperative CVA, and improved but persistent CM, which was defined as immediate postoperative CVA that was at least 0.5 cm better than preoperative CVA but still ≥ 3 cm; both groups included only patients with preoperative CM. Immediate postoperative radiographs were obtained when the patient was discharged from the hospital after surgery. Demographic, radiographic, and operative variables were collected. Outcomes included major complications, readmissions, reoperations, and patient-reported outcomes (PROs). The t-test, Kruskal-Wallis test, and univariate logistic regression were performed for statistical analysis. In this study, 243 patients were included, and the mean ± SD age was 49.3 ± 18.3 years and the mean number of instrumented levels was 13.5 ± 3.9. The mean preoperative CVA was 2.9 ± 2.7 cm. Of 153/243 patients without preoperative CM (CVA < 3 cm), 13/153 (8.5%) had postoperative iatrogenic CM. In total, 43/243 patients (17.7%) had postoperative CM: iatrogenic CM (13/43 [30.2%]), unchanged/worsened CM (19/43 [44.2%]), and improved but persistent CM (11/43 [25.6%]). Significant risk factors associated with iatrogenic CM were anxiety/depression (OR 3.54, p = 0.04), greater preoperative sagittal vertical axis (SVA) (OR 1.13, p = 0.007), greater preoperative pelvic obliquity (OR 1.41, p = 0.019), lumbosacral fractional (LSF) curve concavity to the same side of the CVA (OR 11.67, p = 0.020), maximum Cobb concavity opposite the CVA (OR 3.85, p = 0.048), and three-column osteotomy (OR 4.34, p = 0.028). In total, 12/13 (92%) iatrogenic CM patients had an LSF curve concavity to the same side as the CVA. Among iatrogenic CM patients, mean pelvic obliquity was 3.1°, 4 (31%) patients had pelvic obliquity > 3°, mean preoperative absolute SVA was 8.0 cm, and 7 (54%) patients had preoperative sagittal malalignment. Patients with iatrogenic CM were more likely to sustain a major complication during the 2-year postoperative period than patients without iatrogenic CM (12% vs 33%, p = 0.046), yet readmission, reoperation, and PROs were similar. Postoperative iatrogenic CM occurred in 9% of ASD patients with preoperative normal coronal alignment (CVA < 3 cm). ASD patients who were most at risk for iatrogenic CM included those with preoperative sagittal malalignment, increased pelvic obliquity, LSF curve concavity to the same side as the CVA, and maximum Cobb angle concavity opposite the CVA, as well as those who underwent a three-column osteotomy. Despite sustaining more major complications, iatrogenic CM patients did not have increased risk of readmission, reoperation, or worse PROs.

Preoperative pelvic obliquity: possible relation to postoperative coronal decompensation in thoracolumbar/lumbar adolescent idiopathic scoliosis.

Pelvic obliquity is frequently observed in patients with adolescent idiopathic scoliosis with thoracolumbar/lumbar (TL/L) curve. This study aimed to assess pelvic obliquity changes and their effects on clinical outcomes of posterior fusion surgery. Data in 80 patients (69 with type 5C and 11 with type 6C adolescent idiopathic scoliosis) who underwent posterior fusion surgery were retrospectively analyzed. Pelvic obliquity was defined as an absolute pelvic obliquity angle (POA) value of ≥ 3°. The patients were divided into groups according to preoperative pelvic obliquity. Moreover, patients with preoperative pelvic obliquity were divided based on POA change from preoperative values versus 2 years postoperatively. Patients were divided based on the presence of selective or nonselective TL/L fusion. Radiographic parameters and clinical outcomes were compared between these groups. Among 80 patients, 41 (51%) showed preoperative pelvic obliquity, and its direction was upward to the right for all cases. Coronal decompensation 2 years postoperatively was significantly elevated in patients with preoperative pelvic obliquity (p < 0.05). Thirty-two patients (40%) displayed pelvic obliquity 2 years postoperatively. Among 41 patients with preoperative pelvic obliquity, 22 patients (54%) were in the group with a decrease in POA, and 19 were in the group with no decrease. The group with no decrease in POA showed significant TL/L curve progression throughout the postoperative follow-up period. The patients with nonselective fusion showed a significantly lower incidence of pelvic obliquity at 2 years postoperatively. Postoperative coronal decompensation more frequently occurred in patients with preoperative pelvic obliquity than in those without pelvic obliquity preoperatively. In addition, postoperative pelvic obliquity changes may be related to residual lumbar curve behavior.

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.

RESULTADOS CLÍNICO-RADIOLÓGICOS DO TRATAMENTO DA ESCOLIOSE NEUROMUSCULAR COM PARAFUSOS S2-ALAR-ILÍACO GUIADOS POR NAVEGAÇÃO INTRAOPERATÓRIA

ABSTRACT Objective: Analyze the clinical and radiological aspects of the S2AI screw technique in patients with neuromuscular scoliosis undergoing deformity correction surgery by intraoperative navigation. Methods: Retrospective analysis of medical records of patients undergoing neuromuscular scoliosis correction surgery with the S2-alar-iliac technique between 2017-2020. Results: In the total sample of 35 patients, 18 (51.4%) were female, with an average age of 14.9. The average preoperative coronal curve was 100° ± 26.2, with an average correction of 55% ± 16.3, with an average coronal curve of 44.8°± 19.5 at the end of surgery and 45 ° ± 19.6 at the end of follow-up. The average preoperative pelvic obliquity was 27.9°± 10.9, with a correction rate of 66.1% ± 27.6, being 8.2° ± 5.4 at the end of surgery and 9 .4°± 7.0 at the end of the follow-up. The average of operated levels was 17.3± 0.7. All 70 S2 screws had a diameter of 7mm. The average duration of surgeries was 416 ± 86 minutes, with estimated intraoperative bleeding of 921 ± 394.1 ml. The average density of screws in the sample was 1.3 ± 0.2 screws per level, and the average density in the lumbosacral spine was 1.5 ± 0.2. Conclusions: Intraoperative navigation can contribute to the rate of complications related to the S2AI screw decrease; in addition, the length of this screw appears to have significant relevance in maintaining the correction throughout the follow-up. Level of evidence IV; Case series.

36. Understanding the role of pelvic obliquity and leg length discrepancy in adult spinal deformity patients with coronal malalignment: unlocking the black box

<h3>BACKGROUND CONTEXT</h3> Achieving optimal coronal alignment can be a formidable challenge in adult spinal deformity surgery, and how pelvic obliquity and leg length discrepancy relate to coronal malalignment remains poorly studied. <h3>PURPOSE</h3> Pelvic obliquity (PO) and leg length discrepancy (LLD) are associated with preoperative and postoperative coronal malalignment (CM) in surgical adult spinal deformity (ASD) patients. <h3>STUDY DESIGN/SETTING</h3> Retrospective cohort. <h3>PATIENT SAMPLE</h3> A total of 237 patients undergoing ASD surgery at a single institution. <h3>OUTCOME MEASURES</h3> Pelvic obliquity, leg-length discrepancy, coronal malalignment. <h3>METHODS</h3> Patients undergoing ASD surgery (≥6 level fusions) were reviewed from a single-institution. Variables were:1) Pelvic obliquity (PO): angle between horizontal plane and a line touching bilateral iliac crests; 2) Leg-length discrepancy (LLD): distance from femoral head to the tibial plafond. Coronal vertical axis (CVA) and sagittal vertical axis (SVA) were collected, both measured from C7. Coronal malalignment (CM)= CVA >3cm. Oswestry Disability Index (ODI) was collected at preoperative and 2-years postoperative. <h3>RESULTS</h3> Of 237 patients undergoing ASD surgery, 90 (37.0%) had preoperative CM. Patients with preoperative CM had a higher PO (2.8±3.2 vs 2.0±1.7, p=0.013), higher percent of patients with PO>3° (35.6% vs 23.5%, p=0.044), and higher percent of patients with LLD>1 cm (21.1% vs 9.8%, p=0.014). While preoperative PO was significantly correlated with CVA (r=0.26, p<0.001) and max Cobb angle (r=0.30, p<0.001), preoperative LLD was only correlated with CVA (r=0.14, p=0.035). 12.2% of CM patients had both clinically significant PO and LLD. Postoperatively, preop PO was significantly associated with both postoperative CM (OR=1.22, 95%CI, p=0.008) and postoperative CVA (β=0.11, p<0.001). A higher preop PO was independently associated with postop complications after multivariate logistic regression (OR=1.24, p=0.010); however, 2-year ODI scores were not. Preoperative LLD had no significant relationship to postop CM, CVA, ODI or complications. <h3>CONCLUSIONS</h3> Clinically significant pelvic obliquity ≥3° or leg-length discrepancy ≥1 cm was seen in 44.1% of patients with preoperative coronal malalignment, but also 23.5% of patients with normal coronal alignment. Preoperative pelvic obliquity was significantly associated with preoperative coronal vertical axis and max Cobb angle, while preoperative leg-length discrepancy was only associated with preoperative coronal vertical axis. The direction of pelvic obliquity and leg-length discrepancy showed no consistent pattern with coronal vertical axis. Preoperative pelvic obliquity was independently associated with complications but not 2-year ODI scores. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

P31. Preoperative predictors for postoperative gastrointestinal complications in pediatric neuromuscular scoliosis patients

<h3>BACKGROUND CONTEXT</h3> Neuromuscular scoliosis patients have a purportedly higher postoperative complication rate than those with adolescent idiopathic scoliosis. Of these, gastrointestinal (GI) issues are clinically well observed. However, there is limited data on the prevalence of postoperative GI complications, and the preoperative indicators that may predict them. <h3>PURPOSE</h3> The focus of this study is to determine the incidence and risk factors of gastrointestinal complications after neuromuscular scoliosis correction. <h3>STUDY DESIGN/SETTING</h3> Retrospective case review. <h3>PATIENT SAMPLE</h3> Inclusion criteria focused on pediatric scoliosis patients (<18 years of age) with a neuromuscular diagnosis undergoing index procedures. <h3>OUTCOME MEASURES</h3> Radiographic, clinical and hospital stay data was assessed. Patients were compared according to their postoperative gastrointestinal (GI) complication status. PO GI issues were described as either major or minor complications. Minor complications included continued nausea/vomiting, constipation, diarrhea and distention. Major complications included extended paralytic ileus, dysphagia, g-tube infections and gastroparesis based on literature and clinical experience. <h3>METHODS</h3> An IRB approved, retrospective case review of patient records from 2013 – 2019. Data was presented as median and interquartile values in order to avoid the effects of outsider values. Statistically, Fisher's Exact, Kruskal-Wallis and Chi-Squared tests were used. <h3>RESULTS</h3> We included a total of 69 patients, of which, 36 developed PO GI issues. Age and BMI values were similar for both groups of patients (p = 0.367, p = 0.371). Of the patients that developed PO GI complications, the overwhelming majority exhibited minor complications only (94.3%). PO GI patients had a significantly longer length of stay (9 vs 6 days, p = 0.004). While preoperative major Cobb angles were similar, patients that developed PO GI issues had a significantly higher preoperative pelvic obliquity (15.80 cm vs 7.55 cm, p = 0.040). Patients that developed PO GI issues were overwhelmingly classified with ASA scores of 3 or 4 (96.6%), were more likely to have a preoperative gastrostomy tube (p < 0.001), were significantly more likely to be fused to the pelvis (p = 0.009), had longer fusions (17 vs 15, p = 0.018) and had significantly more spastic presentations of their disease (p < 0.001). Both groups had similar preoperative albumin levels (p = 0.344), history of seizures (p = 0.132) and gastroesophageal reflux (p = 0.096). Patients with postoperative GI issues were significantly more likely to have a pre-existing GI such as aspiration, feeding issues and g-tube site complications (p = 0.023). <h3>CONCLUSIONS</h3> Spasticity, the presence of a pre-existing GI issue, presence of a g-tube, and notable pelvic tilt appear to be significant risk factors for postoperative gastrointestinal complications in neuromuscular scoliosis patient. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Neuromuscular Scoliosis: Comorbidities and Complications.

Study DesignSingle-center, retrospective cohort study conducted from 2013 to 2017.PurposeTo determine the risk factors for surgical complications in neuromuscular scoliosis based on known patient comorbidities.Overview of LiteratureThe concept of neuromuscular scoliosis includes a wide variety of pathologies affecting the neuromuscular system. Complications are numerous and are often difficult to predict.MethodsA retrospective analysis of a single-center database was conducted from 2013 to 2017. Inclusion criteria were patients aged <25 years, diagnosis of neuromuscular scoliosis, and history of posterior fusion deformity surgery. A total of 64 patients (mean age, 15 years; 63% females) were included in this study. Clinical, radiological, and laboratory parameters in the preoperative, intraoperative, and postoperative settings were analyzed. Univariate analysis was performed using Student t-test for continuous variables, and a chi-square test was used for noncontinuous variables. Multivariate analysis was performed to identify predictors of major, mechanical, and total complications.ResultsComplications were found in 44% of patients, with 46.9% consisting of major complications, and 84.4% being early complications. Univariate analysis revealed that the presence of perinatal comorbidities, independent of other comorbidities, increased the risk for complications (p=0.029). Preoperative hypoglycemia, high number of instrumented levels, longer surgical time, use of an all-screw construct, lower preoperative pelvic obliquity, postoperative lower kyphosis, high thoracic spinopelvic angle (as measured by T9 spino-pelvic inclination), absence of deep drain, and use of superficial drain were associated with postoperative complications (all p<0.05). Logistic regression demonstrated that comorbidities, longer surgical time, hypoglycemia, and absence of deep drains are predictors of complications. Independent variables that predicted major complications were the number of levels fused, postoperative kyphosis (p=0.025; odds ratio [OR], 1.074), and high screw density (p=0.014; OR, 4.380).ConclusionsComplications in neuromuscular scoliosis are increased by comorbidities, long surgical time, and inadequate correction. Preventative measures to decrease these complications include appropriate preoperative patient preparation and surgical planning.

The modified Kostuik transilial bar technique has acceptable results in neuromuscular spinal deformity correction.

The aim of this study is to evaluate the results of the modified Kostuik transilial bar technique for neuromuscular scoliosis (NS). We reviewed the records of 21 patients treated for NS with this instrumentation. There were 14 females and seven males, with an average age of 15.6 years (range: 9-21 years). We determined patients' demographics, correction ratio of both curve and pelvic obliquity, loss of correction, screw loosening at first sacral vertebra, and clinical outcomes. Mean follow-up was 56 months (range: 34-96 months). There were no reoperations, no screw breakage, and no significant loss of correction. The mean preoperative coronal Cobb angle was 71.4°±8.7°, the initial postoperative measurements had a mean Cobb angle of 19.2°±7.2°, and at the last follow-up, the mean Cobb angle was 23.6°±6.9° (P<0.001). Pelvic obliquity decreased from 27.7°±12.4° to 9.1°±5.3° at follow-up and to 11.9°±6.3° at the last follow-up (P<0.001). The preoperative pelvic obliquity angle was significantly higher at the patients with screw loosening (P=0.016). There was one established as well as one possible pseudoarthrosis in our patients. The new technique does appear to possibly become an alternative to conventional lumbosacral fixation techniques. Integration of the bar with pipe-type connector onto the long spinal instrumentation with oblique connectors can prevent the most unenviable complications such as wide exposure, hardware prominence, reoperation, and pseudoarthrosis.

Safety and Efficacy of Treatment for Scolios Is Secondary to Spinal Muscular Atrophy Fused to Lumbar 5 Level.

Introduction Patients with spinal muscular atrophy (SMA) usually have progressive scoliosis. Although fusion of the sacrum or pelvis has been recommended for correcting pelvic obliquity (PO), the procedure is invasive. This study determined as to whether performing instrumentation to the fifth lumbar vertebra (L5) is safe and effective for scoliosis in patients with SMA. Methods Twelve patients with SMA underwent posterior spinal fusion and stopping instrumentation at the L5 level. We evaluated age at surgery, the duration of surgery, blood loss, complications, preoperative and postoperative Cobb angles, and PO. Results The mean age at surgery was 11.4 years; the mean duration of surgery was 319 minutes, and the mean blood loss was 1170 mL. The Cobb angle improved from 97.3° to 39.1° at 1 month postoperatively (correction rate, 60.9%) and to 42.3° at the final follow-up. PO was corrected from 27.8° to 13.1° at 1 month postoperatively (correction rate, 51.7%) and to 19.8° at the final follow-up. No complications were reported. All patients showed improvement in low back pain, with reduced difficulty while sitting. However, >10% correction loss of PO was observed in 6 patients with high preoperative PO. Conclusions The correction rate of scoliosis in SMA patients with posterior spinal fusion and instrumentation to the L5 level was acceptable, and no complications occurred. Scoliosis associated with SMA was more rigid and severer than scoliosis associated with Duchenne muscular dystrophy. Correction rates of the Cobb angle and PO in SMA patients with instrumentation to L5 were similar to those in SMA patients with instrumentation to the sacrum or pelvis. Correction loss of PO was greater in patients with high preoperative PO than in those with low preoperative PO. Instrumentation and fusion to L5 for scoliosis in patients with SMA seems safe and effective, except in cases of high preoperative PO.

Resolution of pelvic obliquity after correction surgery for congenital scoliosis

Objective To investigate resolution of pelvic obliquity after spinal correction surgery for congenital scoliosis and explore predictor factors of correction of pelvic obliquity after surgery. Methods A retrospective study was performed on congenital scoliosis (CS) patients who underwent scoliosis correction surgery in our hospital from March 2000 to May 2016. A total of 352 patients received correction surgery for scoliosis. According to inclusion criteria and exclusion criteria, 21 CS patients with pelvic obliquity and without leg inequality were included. Of the 21 patients, 9 were males and 12 were females. The mean age was (13.2±10.2) years (range 4 to 36 years). 10 patients were diagnosed as hemivertebrae, 7 as unsegmentation and 4 mixed. 6 CS patients received posterior correction surgery for scoliosis without any osteotomy. 10 received posterior instrumentation and posterior vertebral column resection. 5 received posterior instrumentation and pedicle subtraction osteotomy. The following parameters were measured at pre- and postoperative standing full spine X-ray radiographs: Cobb angle of major curve, trunk shift (TS), pelvic obliquity angle (POA), L5 obliquity angle (L5OA), and lumbar-sacral angle (LSA). Bivariate correlation analysis was conducted to investigate radiographic factors related to correction of pelvic obliquity after surgery. Results Preoperative Cobb angle of major curve improved from 63°±27° to 37°±18° after surgery. Preoperative trunk shift decreased from (42±31) mm to (21±11) mm after surgery. Preoperative pelvic obliquity angle decreased from 16°±7° to 7°±4° after surgery. Preoperative L5 obliquity angle decreased from 23°±11° to 10°±5°after surgery. Preoperative lumbar-sacral angle decreased from 12°±6° to 7°±4° after surgery. The differences of preoperative and postoperative radiographic parameters were statistically significant. Preoperative POA was not correlated to preoperative Cobb angle of major curve, but positively Cobb angle of major curve correlated to preoperative TS, L5OA, and LSA. The difference of pre- and postoperative POA were positively correlated to the differences of pre- and postoperative Cobb angle of major curve, TS, L5OA, and LSA. Conclusion Scoliosis correction surgery could effectively level pelvic for patients with congenital scoliosis and pelvic obliquity. L5OA and LSA could be predictors for pelvic obliquity after scoliosis correction surgery. Key words: Scoliosis; Pelvis; Radiography

Correction of Pelvic Obliquity After Spinopelvic Fixation in Children With Cerebral Palsy: A Comparison Study With Minimum Two-Year Follow-up

Study DesignSingle institution cohort data were collected prospectively and reviewed retrospectively. ObjectivesThis study aims to compare outcomes among three different instrumentation types: unit rod, iliac screws, and sacral alar iliac (SAI) screws in terms of pelvic obliquity correction in children with cerebral palsy (CP). Summary of Background DataThe optimal choice for spinopelvic fixation in CP scoliosis with pelvic obliquity is controversial. MethodsPatients with minimum 2 years' follow-up were divided into three groups according to instrumentation type and matched based on preoperative pelvic obliquity and coronal major curve magnitude. Radiographic measurements included horizontal pelvic obliquity angle (PO), spinopelvic angle (SPA), coronal and sagittal Cobb angles, and T1 pelvic angle. Procedures were performed in one pediatric institution between 2004 and 2012. All measurements were performed by a single independent reviewer who was not involved in the procedures. ResultsSeventy-seven patients (42 unit rod, 14 iliac screw, and 21 SAI screw) were included. Gender and age distribution was similar across all groups (56% males, 44% females, mean age 13.5 years). Mean follow-up was 3.6 years. Comparing pre- and postoperative measurements, there was a significant decrease (p < .05) in PO, SPA, and coronal major cob angle in all groups. No significant loss of correction occurred during follow-up. Postoperatively, TPA improved in all groups. Nonsymptomatic loosening was noted in 59% of unit rods, 57% of iliac screws, and 52% of SAI screws. One prominent iliac screw needed removal. One nonsymptomatic rod fracture, one infected pseudarthrosis, and one rod malposition occurred in unit rod group. ConclusionsThis study suggests that for correction of pelvic obliquity in cerebral palsy scoliosis, iliac and SAI screws were similar to the unit rod in comparative effectiveness and implant safety profile. Level of evidenceTherapeutic study, Level III.

Are S1 Screws a Useful Adjunct to Iliac Screws in Long Fusions to the Sacrum in Cerebral Palsy?

Multicenter prospective database review of patients with cerebral palsy (CP) and spinal deformity. To determine if the type of distal fixation is associated with improved correction of coronal deformity or pelvic obliquity (PO) at 2 years in long posterior fusions to the sacrum. Multiple techniques are utilized for distal fixation in patients with CP. Although there is emerging evidence that the augmentation of iliac screws with S1 screws may be beneficial, this remains controversial. A prospective, multicenter database was used to identify patients with CP who underwent long posterior fusions to the sacrum. Eighty-eight patients were included, 52 with iliac screws (I) and 36 with iliac and S1 screws (IS) for distal fixation. Preoperative, first erect, and 2-year follow-up radiographs and complications were analyzed. Statistical analysis was performed using ANOVA and repeated measures ANOVA with significance set at P < 0.05. Scoliosis was the primary deformity in greater than 90% of patients in both groups (P=0.84). Preoperative coronal deformity was similar (I = 83°, IS = 87°, P = 0.49), but correction was better with the use of S1 screws on the first erect radiograph and at 2 years (I = 35°, IS = 22°, P = 0.001), reflecting correction of 58% and 74% for iliac and iliac-S1 screws, respectively (P < 0.001). Preoperative PO was similar (I = 29°, IS = 30°, P = 0.71) and was noted to improve more in the iliac-S1 group by 2 years (I = 11°, IS = 5°, P = 0.004), representing correction of 60% and 77% for the iliac and iliac-S1 groups, respectively (P = 0.018). There was no difference in the rate of major (P = 0.27) or minor (P = 0.65) complications in either group. Bilateral S1 and iliac screws are associated with improved spinal deformity and PO correction at 2 years in the CP population. Two points of distal fixation, S1, and ilium should be considered for this population. 3.

A radiolucent chair for sitting-posture radiographs in non-ambulatory children: use in biplanar digital slot-scanning.

EOS imaging (EOS System; EOS imaging, Paris, France) enables fast 2-D/3-D imaging of children in standing load-bearing position. Non-ambulatory children with neuromuscular scoliosis need evaluation of their spinal balance while in a normal daily position. We designed a customized chair fitting the EOS patient-area dimensions to obtain images in natural sitting postures. The chair is a 360° rotating orthopaedic chair made of fully radiolucent polyethylene and equipped with an adjustable headrest and three-point belts. Out of 41 consecutive patients, 36 (88%, 95% confidence interval 74-96%) had successful imaging. In most patients with severe neuromuscular trunk deformities, the EOS system combined with our chair was useful for assessing preoperative trunk collapse, pelvic obliquity and postoperative corrections in all planes. This specific device changed our daily practice for the assessment of spinal deformities in non-ambulatory patients.