Pelvic fixation for neuromuscular scoliosis deformity correction

Long-term reoperation rates following spinal fusion for neuromuscular scoliosis in nonambulatory patients with cerebral palsy

PURPOSE

To describe the incidence of reoperation and factors contributing to surgical revision within a minimum of 10 years after spinal fusion for scoliosis in patients with nonambulatory cerebral palsy (CP).

METHODS

We conducted a retrospective review of consecutive nonambulatory patients with CP who underwent primary spinal fusion at a single specialty care center with a minimum of 10 years from their index surgery (surgery dates 2001-2011). Causes of reoperation were classified as implant failure/pseudoarthrosis, surgical site infection (SSI), proximal junctional kyphosis, prominent/symptomatic implants, and implant removal. Reoperation rates with 95% confidence intervals were calculated for each time interval, and an actuarial survival curve was generated.

RESULTS

144 patients met inclusion criteria (mean age = 14.3 ± 2.6 years, 62.5% male); 85.4% had 5 years follow-up data; and 66.0% had 10 years follow-up data. Estimates from the actuarial analysis suggest that 14.9% (95% CI: 10.0-22.0) underwent reoperation by 5 years postsurgery, and 21.7% (95% CI: 15.4-30.1) underwent reoperation by 10 years postsurgery. The most common causes for reoperation were implant failure/pseudoarthrosis, SSI, and prominent/symptomatic implants.

CONCLUSIONS

To our knowledge, this study is the largest long-term follow-up of nonambulatory patients with CP and neuromuscular scoliosis who underwent spinal fusion. Approximately 22% of these patients required reoperation 10 years after their index surgery, primarily due to implant failure/pseudoarthrosis, SSI, and prominent/symptomatic implants. Complications and reoperations continued throughout the 10 years period after index surgery, reinforcing the need for long-term follow-up as these patients transition into adulthood.

LEVEL OF EVIDENCE

III.

3D CT modeling demonstrates the anatomic feasibility of S1AI screw trajectory for spinopelvic fixation in neuromuscular scoliosis

PURPOSE

In patients with neuromuscular scoliosis undergoing posterior spinal fusion, the S2 alar iliac (S2AI) screw trajectory is a safe and effective method of lumbopelvic fixation but can lead to implant prominence. Here we use 3D CT modeling to demonstrate the anatomic feasibility of the S1 alar iliac screw (S1AI) compared to the S2AI trajectory in patients with neuromuscular scoliosis.

METHODS

This retrospective study used CT scans of 14 patients with spinal deformity to create 3D spinal reconstructions and model the insertional anatomy, max length, screw diameter, and potential for implant prominence between 28 S2AI and 28 S1AI screw trajectories.

RESULTS

Patients had a mean age of 14.42 (range 8-21), coronal cobb angle of 85° (range 54-141), and pelvic obliquity of 28° (range 4-51). The maximum length and diameter of both screw trajectories were similar. S1AI screws were, on average, 6.3 ± 5 mm less prominent than S2AI screws relative to the iliac crests. S2AI screws were feasible in all patients, while in two patients, posterior elements of the lumbar spine would interfere with S1AI screw insertion.

CONCLUSION

In this cohort of patients with neuromuscular scoliosis, we demonstrate that the S1AI trajectory offers comparable screw length and diameter to an S2AI screw with less implant prominence. An S1AI screw, however, may not be feasible in some patients due to interference from the posterior elements of the lumbar spine.

Placement of ilio-sacral screws in fusionless technique for pediatric neuromuscular scoliosis utilizing planning software, in conjunction with intraoperative navigation, results in a safer optimal screw: a CT-based study

PURPOSE

The insertion of ilio-sacral (IS) screws for distal anchoring in the instrumentation of pediatric neuromuscular scoliosis (NS) presents a significant challenge, often leading to elevated rates of complications. Utilizing computed tomography (CT) navigation and preoperative planning technology is proposed as a potential solution to mitigate these challenges. This study aims to assess the precision of IS screw placement through CT-graphic measurements, both with and without preoperative planning, followed by navigated IS screw insertion, in pediatric neuromuscular scoliosis.

METHODS

Thirty-two treated patients were grouped based on surgical procedure: planned (P): 19 patients (n = 38 screws) and non-planned (NP): 13 patients (n = 26 screws). All screw placements (P and NP) took place under CT navigation. IS screw trajectories of P-group were drawn preoperatively on CT images with the cranial trajectory planning program and fused with the intraoperative CT images. There are several important anatomical structures that should be avoided when placing the IS screw (L5 root, spinal canal, L5S1 facet, SI joint, neurovascular structures anteriorly to the sacrum, S1 root in the S1 foramen and the intestines). Each trajectory was evaluated based on seven radiographical parameters whom we have enlisted partially based on the essentials of a good trajectory described by Miladi et al. (1: Ilium; 2: SI joint; 3: Promontorium; 4: Sacral plate; 5: Anterior sacral cortex; 6: S1 foramen; 7: Spinal canal). An independent sample T test was executed to compare both groups.

RESULTS

The trajectories in the P group showed a significantly (P < 0.05) higher overall similarity and optimality (12.1 ± 2.1 vs 9.1 ± 2.2 points) compared to the non-planned trajectory.

CONCLUSIONS

Preoperative planning and navigated placement of IS screws on fusion images with intraoperative CT, results in a better trajectory of the ilio-sacral screws.

Intraobserver and Interobserver Reliability of Pelvic Obliquity Measurement Methods in Patients With Idiopathic Scoliosis

BACKGROUND

Despite the importance of the assessment of pelvic obliquity, especially in the planning of surgery, there is no consensus on the pelvic obliquity measurements. The purpose of this study is to assess the intraobserver and interobserver reliability of 4 different pelvic obliquity measuring methods in patients with idiopathic scoliosis (IS): the Osebold, O'Brien, Maloney, and Allen&Ferguson methods.

METHODS

A retrospective cohort of 85 posteroanterior full-spine radiographs in the standing position of patients with IS involving the pelvic obliquity was evaluated by a team of 3 raters. The same researcher recorded the curve magnitude, apical vertebral rotation, Risser grade, curve pattern, and femoral head height difference. The pelvic obliquity angle was measured using the Osebold, O'Brien, Maloney, and Allen&Ferguson methods. The same graders were asked to regrade the same radiographs after at least 1 month.

RESULTS

The Osebold method showed the highest interobserver reliability with an ICC of 0.994 and 0.983. The Allen&Ferguson method had the lowest reliability with an ICC of 0.911 and 0.934, but all of the methods were considered having excellent reliability. The Osebold method also showed the highest intraobserver reliability, ranging from 0.909 to 0.997. The Allen&Ferguson method had the lowest intraobserver reliability, with a range of 0.741 to 0.960. Also, all observers preferred the Osebold Method. The observers reported that the Allen&Ferguson method was considered the most time-consuming method, while the least time-consuming method was specified as the Osebold method.

CONCLUSIONS

To the best of our knowledge, this study is the first to evaluate the intraobserver and interobserver reliability of pelvic obliquity among common measurement methods in patients with idiopathic scoliosis. All methods were evaluated as having excellent to good reliability in this study, but the Osebold method is the most reliable method of measuring pelvic obliquity on a frontal view radiograph in idiopathic scoliosis. The Osebold method is easier to use as it requires only the iliac crests to be visualized.

LEVEL OF EVIDENCE

Level III-Retrospective cohort study.

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

STUDY DESIGN

Nonrandomized controlled cohort.

OBJECTIVE

To compare early results between bipolar fusionless construct (BFC) and single posterior fusion (SPF) surgery in neuromuscular scoliosis (NMS).

BACKGROUND

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.

METHODS

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.

RESULTS

Eighty-nine NMS patients were included: 48 in the SPF group and 41 in the BFC group. Surgery time (203 vs. 241 min), 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.

CONCLUSIONS

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 OF EVIDENCE

Level -lll.

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

PURPOSE

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.

METHODS

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 3 years follow-up (FU). Radiologic measurements and chart review were performed.

RESULTS

Twenty nine patients aged 14 ± 1.5 years 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.

CONCLUSIONS

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.

LEVEL OF EVIDENCE

IV.

The Collateral Effect of Enhanced Recovery After Surgery Protocols on Spine Patients With Neuromuscular Scoliosis

INTRODUCTION

Enhanced recovery after surgery (ERAS) protocols are often specific to a specific type of surgery without assessing the overall effect on the ward. Previous studies have demonstrated reduced length of stay (LOS) with ERAS protocols in patients with adolescent idiopathic scoliosis (AIS), although the patients are often healthy and with few or no comorbidities. In 2018, we used ERAS principles for patients undergoing AIS surgery with a subsequent 40% reduced LOS. The current study aims to assess the potential collateral effect of LOS in patients surgically treated for neuromuscular scoliosis admitted to the same ward and treated by the same staff but without a standardized ERAS protocol.

METHODS

All patients undergoing neuromuscular surgery 2 years before and after ERAS introduction (AIS patients) with a gross motor function classification score of 4 to 5 were included. LOS, intensive care stay, and postoperative complications were recorded. After discharge, all complications leading to readmission and mortality were noted with a minimum of 2 years of follow-up using a nationwide registry.

RESULTS

Forty-six patients were included; 20 pre-ERAS and 26 post-ERAS. Cross groups, there were no differences in diagnosis, preoperative curve size, pulmonary or cardiac comorbidities, weight, sex, or age. Postoperative care in the intensive care unit was unchanged between the two groups (1.2 vs 1.1; P = 0.298). When comparing LOS, we found a 41% reduction in the post-ERAS group (11 vs 6.5; P < 0.001) whereas the 90-day readmission rates were without any significant difference (45% vs 34% P = 0.22) We found no difference in the 2-year mortality in either group.

CONCLUSION

The employment of ERAS principles in a relatively uncomplicated patient group had a positive, collateral effect on more complex patients treated in the same ward. We believe that training involving the caregiving staff is equally important as pharmacological protocols.

Clinical and radiological efficacy of spino-pelvic fixation in the treatment of neuromuscular scoliosis

Pelvic fixation is performed to obtain proper coronal and sagittal alignment when the pelvic obliquity is more than 15º in patients with neuromuscular scoliosis (NMS). Since many NMS patients were wheelchair or bed-ridden status, there has been controversy on the effect of pelvic fixation. Therefore, the purpose of this study is to analyze the effects of pelvic fixation on correction of spinal deformity and quality of life (QoL) in NMS patients. A total of 77 NMS patients who underwent deformity correction were divided into three groups and retrospectively analyzed preoperatively, postoperatively, and at 2-year follow-up: pelvic fixation group (Group A, n = 16), fixed to S1 (Group B, n = 33), and fixed to L5 (Group C, n = 28). The correction rate of scoliosis was 60.0%, 58.0%, and 56.7% in groups A, B, and C, respectively, with no statistical difference (P > 0.05). The correction rate of pelvic obliquity was 61.3%, 42.8%, and 57.5% in respective groups A, B, and C, with no significance (P > 0.05). The correction loss of scoliosis and pelvic obliquity showed no statistical significance between three groups for 2-year follow-up (all Ps > 0.05). There were no significant differences regarding clinical outcomes and postoperative complications among the three groups (all Ps > 0.05). Therefore, pelvic fixation using iliac screws is not substantially influencing radiological and clinical outcomes in the patients with NMS.

Early Complications After Posterior Spinal Fusion in Patients With Rett Syndrome

BACKGROUND

Neuromuscular scoliosis in Rett syndrome (RS) is common, progressive, and often requires posterior spinal fusion (PSF). While PSF is associated with improved overall outcomes, there is a paucity of information describing complications. We aimed to report the postoperative complications, readmissions, and reoperations for patients with RS undergoing PSF.

METHODS

Female pediatric patients with RS treated by PSF with segmental instrumentation, with or without concurrent pelvis fixation, during January 2012 to August 2022 were included. Preoperative patient characteristics, intraoperative data (estimated blood loss, cell saver, packed red blood cells transfused), postoperative complications according to the Modified Clavien-Dindo-Sink classification within 90 days, unplanned readmissions within 30 days, and unplanned reoperations within 90 days were recorded.

RESULTS

A total of 25 females were included. The mean (SD) age at surgery was 12.9 (1.8) years and the mean follow-up of 38.6 (24.9) months. The mean preoperative major coronal curve was 79 degrees (23 degrees) which decreased to 32 degrees (15 degrees) by the last follow-up ( P <0.001). The median estimated blood loss was 600 mL and length of stay was 7 days. There were 81 total postoperative complications (3.2 complications/patient). Eight (32%) had grade IVa complications (disseminated intravascular coagulopathy, hypotensive shock, respiratory failure, chronic urosepsis). Five (20%) patients experienced seizures, 48% had pulmonary complications, and 56% had gastrointestinal complications. There were 3 readmissions (12%) within 30 days for pneumonia and 2 (8%) reoperations (an incision and drainage and C2-T2 fusion for significant kyphosis) within 90 days. One patient also had their fusion extended to the pelvis 1 year later. There were more nonambulatory patients in the group fused to the pelvis, but otherwise no differences between those fused and unfused to the pelvis.

CONCLUSIONS

This is the largest review of early postoperative complications for patients with RS who underwent PSF. PSF effectively reduced the major coronal curve, but surgeons and families should be aware of a high postoperative seizure and respiratory complication rate, as well as 8% having reoperations within 90 days and 12% being readmitted within 30 days.

LEVEL OF EVIDENCE

Level IV-therapeutic study.

Long-term outcomes of ilio-sacral screws in minimally invasive bipolar fusionless technique for neuromuscular scoliosis: a retrospective study in 167 patients

INTRODUCTION

Pelvic fixation in patients with neuromuscular scoliosis is difficult, due to their fragile general condition and poor bone quality. Many techniques have been described, associated with high rates of mechanical complications. The objective of this work was to evaluate the mechanical complications and long-term radiological results of ilio-sacral screw pelvic fixation.

MATERIALS AND METHODS

167 consecutive patients with neuromuscular scoliosis who underwent minimally invasive bipolar fixation with ilio-sacral screw pelvic fixation were retrospectively reviewed. The instrumentation consisted in a bilateral sliding rods construct extended from T1 to the sacrum, anchored proximally by double-hook claws and distally by ilio-sacral screws through a minimally invasive approach. Mechanical complications and radiographic measurements (angle of the major coronal curve, pelvic obliquity, lumbar lordosis) were evaluated preoperatively, postoperatively, and at the last follow-up.

RESULTS

Mean operative age was 12 ± 3 years, and follow-up 6.4 years (3.0-10.4 years). Pelvic obliquity decreased from 20° preoperatively to 5° (77% correction) at last follow-up, Angle of the major coronal curve from 75° to 36° (52% correction), and lumbar lordosis from 28° to 38°. 16 mechanical complications in nine patients occurred: screw prominence (n = 1), connector failure (n = 4), screw malposition (n = 11). Unplanned surgery was required in seven cases, two were managed during rod lengthening, seven did not require treatment.

CONCLUSION

In this series of neuromuscular patients operated by ilio-sacral screws as pelvic fixation, the results were stable with a mean follow-up of more than 6 years and the complication rate was reduced comparatively to the literature.

LEVEL OF EVIDENCE: 4

Sacropelvic fixation

The sacropelvis is not only an anatomically complex region but also a biomechanically unique zone transferring axial weights via the transitional lumbosacral junction and the pelvic girdle to the lower appendicular skeleton. When the sacral instrumentation alone is insufficient to achieve stability and solid arthrodesis across the lumbosacral junction, as in long-segment fusions, high-grade spondylolisthesis, deformity corrections, complex sacral/lumbosacral injuries, and neoplasms, sacropelvic fixation is indicated. Many modern sacropelvic fixation modalities outperform historical modalities, especially the conventionally open and percutaneous iliac and S2-alar-iliac screw (S2AI) fixation techniques. Novel screw insertion technologies such as navigation and robotics and modern screw designs aim to maximize the accuracy of screw placement and minimize complications. This review addresses the anatomy and biomechanics of the sacropelvic region as well as the indications, evolution, advantages, and disadvantages of various past and contemporary techniques of lumbosacral and sacropelvic fixation.

Three different techniques for pelvic fixation in the management of neuromuscular scoliosis in nonambulatory spastic cerebral palsy: A comparative study of Galveston Rod, iliac screw, and sacroiliac screw

OBJECTIVE

This study aimed to compare the clinical and radiographic results of three different pelvic fixation techniques, i.e., Galveston Rod, Iliac Screw, and Sacroiliac Screw, in managing neuromuscular scoliosis in nonambulatory children with spastic cerebral palsy (CP).

METHODS

This retrospective study included nonambulatory children aged < 18 years with neuromuscular scoliosis secondary to CP, undergoing a spinal fusion and pelvic fixation by either Galveston rod, iliac screw, or sacroiliac screw techniques. The primary outcome variable was to determine the stability of the major curve angle and pelvic obliquity over timeline intervals for each pelvic fixation tech nique. The two radiographic parameters were measured at five timeline intervals and were compared to define stability among the groups.

RESULTS

One hundred and one patients (54 females [53%]) with spastic nonambulatory CP met the inclusion criteria; the mean age at sur gery was 13.5±3.1 years. Mean follow-up intervals were first-year (12.9±1.5) and second-year (25.8±2.5). Forty-one patients had minimum five-year (81.5±23 months) postoperative follow-up. Groups were based on pelvic fixation techniques: 25 patients with the Galveston rod, 24 with the iliac screw, and 52 with the sacroiliac screw. Of the 41 patients with a minimum five-year follow-up, 10 had the Galveston rod, 11 had an iliac screw, and 20 had sacroiliac screw fixation. Gross Motor Function Classification System level, medical comorbidities, intra thecal baclofen pump, and vitamin D level were compared with each pelvic fixation technique (P > .05). Major curve angle parameters were measured at the five timelines as 70.5°±21.1°, 15.7°±13°, 15.7°±12°, 17.5°±12.7°, and 15.1°±9.6°, and pelvic obliquity as 14.8°±10.4°, 4.9°±4.2°, 5.7°±4.6°, 5°±4.4°, and 7.2°±4.4°, respectively. After the surgery, corrected major curve angle and pelvic obliquity showed no sta tistically significant difference between pelvic fixation techniques (P > .05) and remained stable over timeline intervals (P > .05). Fifteen patients had complications requiring additional surgery. The iliac screw group (nine patients) had the highest rate of complications.

CONCLUSION

All three pelvic fixation techniques can provide equivalent correction for major curve angle and pelvic obliquity in managing neuromuscular scoliosis in nonambulatory CP children. Pelvic obliquity after surgery may remain stable regardless of pelvic fixation type. A higher rate of postoperative complication can be encountered with the iliac screw.

LEVEL OF EVIDENCE

Level III, Retrospective Study.

How to rectify the convex coronal imbalance in patients with unstable dystrophic scoliosis secondary to type I neurofibromatosis: experience from a case series

BACKGROUND

There was a paucity of valid information on how to rectify the convex coronal imbalance effectively in dystrophic scoliosis secondary to Type I neurofibromatosis (DS-NF1), while postoperative inadvertent aggravation of CCI occurred regularly resulting in poor patient satisfaction. We aimed to identify the risk factors for persistent postoperative CCI in DS-NF1, and to optimize the coronal rebalancing strategies based on the lessons learned from this rare case series.

METHODS

NF1-related scoliosis database was reviewed and those with significant CCI (> 3 cm) were identified, sorted and the outcomes of surgical coronal rebalance were analyzed to identify the factors being responsible for failure of CCI correction.

RESULTS

CCI with dystrophic thoracolumbar/lumbar apex was prone to remain uncorrected (7 failure cases in 11) when compared to those with thoracic apex (0 failure cases in 4) (63.6% vs. 0.0%, p = 0.077). Further comparison between those with and without post-op CCI showed a higher correction of main curve Cobb angle (65.9 ± 9.1% vs. 51.5 ± 37.3%, p = 0.040), more tilted instrumentation (10.3 ± 3.6° vs. 3.2 ± 3.1°, p = 0.001) and reverse tilt and translation of upper instrumented vertebra (UIV) to convex side (8.0 ± 2.3° vs. -3.4 ± 5.9°, p < 0.001; 35.4 ± 6.9 mm vs. 12.3 ± 13.1 mm, p = 0.001) in the uncorrected imbalanced group. Multiple linear regression analysis revealed that △UIV translation (pre- to post-operation) (β = 0.832; p = 0.030) was significantly correlated with the correction of CBD.

CONCLUSION

Thoracolumbar/lumbar CCI in dystrophic scoliosis was prone to suffer high risk of persistent post-op CCI. Satisfying coronal rebalance should avoid UIV tilt and translation to the convex side, tilted morphology of instrumentation and over correction maneuvers for main curve, the upper hemi-curve region in particular.

Uncorrected Pelvic Obliquity Is Associated With Worse Health-related Quality of Life (HRQoL) in Children and Their Caregivers at the End of Surgical Treatment for Early Onset Scoliosis (EOS)

BACKGROUND

While largely of concern in nonambulatory patients, pelvic obliquity (PO) can be found in many patients with early onset scoliosis (EOS) and may remain following surgery. However, its association with health-related quality of life (HRQoL) in children and their caregivers at the end of treatment is not well understood. The purpose of this study was to investigate the association between residual PO and HRQoL in children and their caregivers at the end of surgical treatment in ambulatory patients with EOS.

METHODS

In this retrospective cohort study, a multicenter EOS registry was queried to identify ambulatory patients who underwent definitive posterior spinal fusion (PSF) from 2012 to 2019. Patients with fusions extending to the pelvis were excluded. PO was measured at least 1 year following PSF. HRQoL, Parental Burden, Financial Burden, and Satisfaction were assessed through the 24-Item Early Onset Scoliosis Questionnaire (EOSQ-24) also at a minimum of 1 year following PSF.

RESULTS

A total of 155 patients (12.5±2.1 y, 73.5% female) were included. Etiology distribution was 30.3% congenital, 12.9% neuromuscular, 21.3% syndromic, and 35.5% idiopathic. In congenital patients, those with residual PO >8 degrees had worse Satisfaction by 23.2 points compared with those with PO ≤8 degrees. In neuromuscular patients, those with residual PO >7 degrees had worse HRQoL by 16.1 points and Parental Burden by 22.3 points compared with their counterparts. In syndromic patients, those with residual PO >8 degrees had worse HRQoL by 14.8 points, Parental Burden by 16.4 points, and Satisfaction by 21.2 points compared with their counterparts. In idiopathic patients, those with >9 degrees of residual PO had worse HRQoL by 15.0 points and Financial Burden by 26.8 points compared with their counterparts.

CONCLUSIONS

Remaining PO at the end of surgical treatment is associated with worse HRQoL in ambulatory children and their caregivers. These results suggest that correction of PO should remain a primary goal of treatment in patients with EOS undergoing surgery.

LEVEL OF EVIDENCE

Level II-multicenter retrospective cohort study investigating prognosis.

Leg length discrepancy and adolescent idiopathic scoliosis: clinical and radiological characteristics

PURPOSE

This retrospective study aimed to present the clinical and radiological features of functional scoliosis due to LLD and LLD concurrent with AIS; it also aimed to define their relationships for differentiating functional scoliosis due to LLD and LLD concurrent with AIS.

METHODS

This study was conducted as a single-center retrospective comparative study on 47 scoliosis patients with diagnosed LLD, aged 10-18 years. Cases with a diagnosis of structural LLD were divided into two groups according to the presence or absence of concurrent AIS. Data on demographics and the angle of trunk rotation on a sacral basis (ATR_sacrum) were recorded. Limb length was clinically measured with a tape measure and clinical LLD (C-LLD) scoliometer test. Cobb angle, axial rotation, pelvic obliquity, and radiological LLD (R-LLD) were obtained from standing spine radiographs and measured by two blinded orthopedic spine surgeons.

RESULTS

The prevalence of LLD was 6.7% in scoliosis patients in our study population. Cobb angle and apical rotation were higher in the LLD concurrent with AIS group than in the LLD group (p ≤ 0.05). The C-LLD_{scoliometer test} results were strongly correlated with both C-LLD_{tape measure} (r = 0.651; p = 0.000) and ATR_sacrum (r = 0.688; p = 0.000).

CONCLUSION

LLD may develop as a result of adaptive changes due to scoliosis, or a concurrent condition to scoliosis. Cobb angle and apical rotation are the features that differentiate AIS from functional scoliosis in patients with LLD. The C-LLD scoliometer test can be an effective, practical, and useful method for measuring C-LLD, but its validity and reliability should be determined.

TRIAL REGISTRATION

This study was retrospectively registered at ClinicalTrials.gov (number: NCT04713397, date of registration: 01/14/2021).

LEVEL OF EVIDENCE

III.

The relationship between S1 screw loosening and postoperative outcome in patients with degenerative lumbar scoliosis

Background

When choosing S1 as the lowest level of instrumentation, there are many complications may come out such as S1 screw loosening. Facing this problem, there has been various techniques for the protection of S1 screw including sacropelvic fixation, bicortical or tricortical insertion of S1 screw.

Objective

This study aimed to explore the risk factors for the S1 screw loosening, then to demonstrate the relationship between S1 screw loosening and postoperative outcome for patients with degenerative lumbar scoliosis (DLS).

Methods

Patients who underwent lumbosacral fixation for DLS were evaluated retrospectively. They were divided into two groups according to the S1 pedicle screw at the follow-up. Age, gender, bone mineral density, body mass index, history of smoking, the number of instrumented levels, comorbidities, complications and radiological parameters were collected. We established logistic regression analysis to determine independent risk factors for S1 screw loosening and multiple linear regression to identify whether S1 screw loosening would influence postoperative clinical outcome.

Results

S1 screw loosening rate was up to 41.0% (32/78). Patients were older in the S1 screw loosening group than those in the control group (P < 0.05). Compared with the control group, the rate of osteoporosis was higher in screw loosening group than that in the control group (P < 0.05). Older age and osteoporosis were independent risk factors for S1 screw loosening (P < 0.05). In the screw loosening group, the rate of hypertension was higher than that in the control group (P < 0.05). The relationship of S1 screw loosening and ODI was not significant in the multiple linear regression (P > 0.05). The clinical outcome was similar in the S1 screw loosening group and control group (P > 0.05).

Conclusion

Older age and osteoporosis are independent risk factors for the S1 screw loosening. Patients with complication of S1 screw loosening are not always along with worse clinical outcome. We should consider potential benefit, complications and medical cost when choosing the lowest instrumented vertebrae for patients with DLS.

Use of the dual construct lowers rod strains in flexion-extension and lateral bending compared to two-rod and two-rod satellite constructs in a cadaveric spine corpectomy model

BACKGROUND CONTEXT

Complex spinal reconstructions involving corpectomies, or osteotomies, place spinal implants at extremely high stresses that can lead to pseudoarthrosis and ultimately to rod failure, resulting in revision surgery. Current clinical options to increase the biomechanical strength of a construct include increasing rod diameter, changing rod material, or placing an additional satellite/outrigger rod on a standard two rod construct. Fundamentally, all of these constructs still rely on two longitudinal rods across the reconstruction site and are therefore at risk for rod fracture and loss of alignment. Initially described in 2006, the Dual Construct was developed to address this limitation by utilizing four distinct mechanically independent rods, which allowed for the creation of two separate, and distinct, constructs within each patient. Although there is early clinical evidence to support its efficacy, this is the first biomechanical study to compare the Dual Construct to the two-rod and two-rod with satellite configurations in a cadaveric study.

PURPOSE

To assess the biomechanical impact of the Dual Construct technique to traditional two-rod and two-rod with satellite rod construct in a cadaveric model.

STUDY DESIGN/SETTING

Biomechanical cadaveric study METHODS: Nine fresh-frozen human cadaveric spines (6 males, 3 females, 56 year +/- 9 years) from T9-pelvis were instrumented and tested utilizing all three configurations including two-rod construct, two-rod with satellite construct, and the Dual Construct technique. Biomechanical testing order of the various constructs was randomized to reduce potential effects of order bias. Strain gauges were placed in both the coronal and sagittal planes of the rods to track the strains during flexion-extension and lateral bending while undergoing range of motion testing. Testing was performed using pure-moment flexibility testing protocols.

RESULTS

In flexion-extension, the resultant strain in the two-rod construct was an average 600±228 microstrain, the two-rod with satellite rod strain averaged 603±237 microstrain, and the Dual Construct averaged 403±149 microstrain. In lateral bending, the resultant strain in the two-rod construct was an average of 266±134 microstrain, the satellite rod strain was an average of 310±158 microstrain, and the Dual Construct averaged 118±51 microstrain. In both flexion extension and lateral bending, a significant reduction in strain was observed between the Dual Construct condition compared to both the two-rod and satellite configurations. No significant difference was found between the two-rod and two-rod with satellite rod configurations.

CONCLUSIONS

The increase in load sharing significantly decreases the strain experienced across the Dual Construct compared to traditional two-rod and two-rod with satellite constructs. Global rod strains on primary rods cannot be reduced by simply increasing the number of satellite rods, but can only be reduce by increasing the actual number of primary rods.

Hybrid versus total sublaminar wires in patients with spinal muscular atrophy undergoing scoliosis surgery

Background

Early versions of spinal muscular atrophy (SMA) scoliosis correction surgery often involved sublaminar devices. Recently, the utilization of pedicle screws has gained much popularity. Pedicle screws are generally believed to provide additional deformity correction, but pedicle size and rotational deformity limit their application in the thoracic spine, resulting in a hybrid construct involving pedicle screws and sublaminar wire. Studies of the efficacy of hybrid instrumentation in SMA scoliosis are often limited by the scarcity of the disease itself. In this study, we aimed to compare the surgical outcomes between hybrid constructs involving pedicle screws and sublaminar wire and sublaminar wire alone in patients with SMA scoliosis.

Methods

We retrospectively reviewed the clinical records and radiographic assessments of patients with SMA scoliosis who underwent corrective surgery between 1993 and 2017. The radiographic assessments included deformity correction and progressive changes in the major curve angle, pelvic tilt (PT) and coronal balance (CB). The correction of deformities was observed postoperatively and at the patient’s 2-year follow-up to test the efficacy of each type of construct.

Results

Thirty-three patients were included in this study. There were 14 and 19 patients in the wiring and hybrid construct groups, respectively. The hybrid construct group demonstrated a higher major curve angle correction (50.5° ± 11.2° vs. 36.4° ± 8.4°, p < 0.001), a higher apical vertebral rotation correction (10.6° ± 3.9° vs. 4.8° ± 2.6°, p < 0.001), and a reduced progression of the major curve angle at the 2-year follow-up (5.1° ± 2.9° vs. 8.7° ± 4.8°, p < 0.001). A moderate correlation was observed between the magnitude of correction of the apical vertebral rotation angle and the major curve (r = 0.528, p = 0.002).

Conclusion

This study demonstrated that hybrid instrumentation can provide a greater magnitude of correction in major curve and apical rotation as well as less major curve progression than sublaminar wire instrumentation alone in patients with SMA scoliosis. Level of evidence III

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04737-0.

Pelvic obliquity associated with neuromuscular scoliosis in cerebral palsy: cause and treatment

STUDY DESIGN

Literature Review.

OBJECTIVE

Review the etiology, clinical manifestations, diagnosis, and treatment of pelvic obliquity in cerebral palsy patients with neuromuscular scoliosis. Neuromuscular scoliosis (NMS) in cerebral palsy (CP) patients is rapidly progressive and often leads to an imbalance in musculoskeletal mechanics that extends to the pelvis. A horizontal misalignment of the pelvis in the frontal plane known as pelvic obliquity (PO) is a common finding in this population. When untreated, PO can exacerbate the back pain, postural strain, and walking difficulties experienced by these patients. Establishing the manifestation and treatment plan for PO in the setting of NMS can provide valuable insight for diagnosis and management.

METHODS

A comprehensive literature review was performed on the etiology, clinical manifestations, diagnosis, and treatment of pelvic obliquity in the setting of NMS in CP. The advantages and limitations of measurement and treatment options were evaluated.

RESULTS

PO is categorized into suprapelvic, infrapelvic, and intrapelvic causes, each presenting with a unique pattern of pathology. NMS in CP with hip contractures and structural deformities fall into these categories. The Maloney and O'Brien methods of pelvic measurement have demonstrated superior utility and are recommended for clinical diagnosis. The management of PO in NMS patients is focused on the cause of malalignment, with posterior fusion, contracture release, and osteotomy encompassing the mainstay of treatment.

CONCLUSION

PO is commonly found in patients with NMS in cerebral palsy. There is currently no standard method for determining the PO angle. Interventions designed to reduce scoliotic curves and release tissue contractures can level the pelvis and restore proper alignment of the spine and sacrum in the coronal plane in these patients. Further understanding of the causes of PO in NMS, as well as the establishment of a standardized measuring technique and diagnostic parameters will allow for more effective treatment options and improve outcomes in patients with CP.

LEVEL OF EVIDENCE

N/A.

Coronal balance with circumferential minimally invasive spinal deformity surgery for the treatment of degenerative scoliosis: are we leaning in the right direction?

OBJECTIVE

Coronal malalignment (CM) in adult spinal deformity is associated with poor outcomes and remains underappreciated in the literature. Recent attempts at classifying CM indicate that some coronal shifts may be more difficult to treat than others. To date, outcomes for circumferential minimally invasive surgery (cMIS) of the spine in the context of these new CM classifications are unreported.

METHODS

A retrospective evaluation of patients with degenerative scoliosis (Cobb angle > 20°) consecutively treated with cMIS at a single institution was performed. Preoperative and 1-year postoperative standing radiographs were used to make the comparisons. Clinical outcome measures were compared. Patients were subgrouped according to the preoperative distance between their C7 plumb line and central sacral vertical line (C7-CSVL) as either coronally aligned (type A, C7-CSVL < 3 cm); shifted ≥ 3 cm toward the concavity (type B); or shifted ≥ 3 cm toward the convexity (type C) of the main lumbar curve.

RESULTS

Forty-two patients were included (mean age 67.7 years). Twenty-six patients (62%) were classified as type A, 5 patients (12%) as type B, and 11 patients (26%) as type C. An average of 4.9 segments were treated. No type A patients developed postoperative CM. All type B patients had CM correction. Six of the 11 type C patients had CM after surgery. Overall, there was an improvement in the C7-CSVL (from 2.4 to 1.8 cm, p = 0.04). Among subgroups, only type B patients improved (from 4.5 to 0.8 cm, p = 0.002); no difference was seen for type A patients (from 1.2 to 1.4 cm, p = 0.32) or type C patients (from 4.3 to 3.1 cm, p = 0.11). Comparing type C patients with postoperative CM versus those without postoperative CM, patients with CM had worse visual analog scale back scores at 1 year (5 vs 1, p = 0.01). Moreover, they had higher postoperative L4 tilt angles (11° vs 5°, p = 0.01), indicating inadequate correction of the lumbosacral fractional curve.

CONCLUSIONS

cMIS improved coronal alignment, curve magnitudes, and clinical outcomes among patients with degenerative scoliosis. It did not result in CM in type A patients and was successful at improving the C7-CSVL in type B patients. Type C patients remain the most difficult to treat coronally, with worse visual analog scale back pain scores in those with postoperative CM. Regional coronal restoration of the lumbosacral fracture curve should be the focus of correction in cMIS for these patients.

Comparative radiological outcomes and complications of sacral-2-alar iliac screw versus iliac screw for sacropelvic fixation

PURPOSE

To compare the outcomes of sacropelvic fixation (SPF) using sacral-2-alar iliac (S2AI) screw with SPF using iliac screw (IS).

METHODS

A comprehensive search of PubMed, EMBASE, Cochrane Central Register of Controlled Trials and Scopus was performed for comparative studies between S2AI and IS for SPF. Two independent investigators selected qualified studies and extracted data indispensably. With 95% confidence intervals (CI), the odds ratio (OR) was applied to dichotomous outcomes and standardized mean difference (SMD) was applied to continuous outcomes for each item.

RESULTS

We included data from thirteen studies involving 722 patients (S2AI, 357 patients; IS, 365 patients). In the pediatric population, the S2AI group had a smaller pelvic obliquity (PO) than the IS group at final follow-up (SMD, - 0.38; 95% CI, - 0.72 to - 0.04). Patients who underwent S2AI screws showed reduced rates of re-operation (S2AI, 13%; IS, 28%), implant failure (S2AI, 12%; IS, 26%) [screw loosening (S2AI, 8%; IS, 20%); screw breakage (S2AI, 2%; IS, 12%)], implant prominence (S2AI, 2%; IS, 14%), pseudarthrosis (S2AI, 3%; IS, 15%), wound infection (S2AI, 8%; IS, 22%) and less blood loss (S2AI, 2035.4 ml; IS, 2708.4 ml).

CONCLUSION

Radiological outcomes indicate an effective maintenance of the correction and arrest of progression of deformity by S2AI, which is equal or better than IS. SPF with S2AI screw has obviously lower incidence of postoperative complications and less blood loss. Given these advantages, the S2AI screw seems to be a beneficial alternative to IS.

Unmet Needs of Surgical Care for Children: A Case Study in the Brazilian Publicly-Financed Health System

Objective  To measure and document the clinical impact of the waiting time for surgical treatment of patients with spinal deformities in a quaternary center in Brazil.

Methods  In total, 59 patients with spinal deformity waiting for surgery on our hospital's list were evaluated to observe the impact of the waiting time on the progression of the deformity. Patient evaluation was performed using the SRS-22r questionnaire for health-related quality of life (HRQL) and radiographic images to evaluate the deformity of the spine at the time the patients were included in the waiting list and at the most recent appointment. The radiographic parameters selected for comparison were: Cobb angle of the primary and secondary curves, coronal alignment, apical vertebral translation, pelvic obliquity, sagittal vertebral axis, kyphosis (T5-T12), and lordosis (L1-S1).

Results  Low HRQL scores according to the SRS-22r questionnaire were observed in patients waiting for surgery. The radiographic parameters showed progression of the deformity on the initial evaluation when compared with the most recent follow-up evaluation.

Conclusion  The patients waiting for surgical treatment of spinal deformities in our center showed relatively low HRQL scores and radiographic progression of the deformity.

The Impact of Spinal Fusion on Hip Displacement in Cerebral Palsy

BACKGROUND AND STUDY AIMS

The aims of this study were to determine the risk of progressive hip subluxation in children with CP after spinal fusion for scoliosis and how frequent the hips follow-up should be scheduled.

PATIENTS AND METHODS

Pelvis radiography [migration index (MI) and pelvic obliquity (PO)] of Gross Motor Function Classification System (GMFCS) levels IV and V children with CP who received spinal fusion and pelvic fixation were reviewed retrospectively. This population was categorized into three groups based on the MI at spinal fusion: G1 = 0-29%; G2 = 30-59%; and G3 = 60-100%.

RESULTS

Fifty children (age 7.5-15.0 years) and categorized into 3 groups (G1 = 19, G2 = 23, G3 = 8; 100 hips in total). Preoperative and last follow-up MI were 22 ± 7% and 30 ± 20% (G1), 41 ± 9% and 43 ± 22% (G2), 92 ± 15% and 97 ± 10% (G3). The MIs at spinal fusion between groups were statistically different (p < 0.001). In G1, the mean MI progression was 5% and 25% at 12 months and 62 months, respectively. In G2, the mean MI progression was 9% and 25% at 12 months and 32 months, respectively. The progression more than 10% occurred within 2 years in G1 and within 1 year in G2. There was no difference between groups based on preoperative degree of PO (p = 0.653) and correction rate in PO (p = 0.421).

CONCLUSIONS

In GMFCS IV and V children with the highest risk for progression occurred with increasing preoperative MI, especially over 50%. Hips should be monitored continuously after spinal fusion until hip stability is documented.

What Factors can Influence Massive Blood Loss in the Surgical Treatment of Neuromuscular Scoliosis?

Objective  The aim of the present study is to identify the incidence, predisposing factors and prognostic impact of blood loss in patients with neuromuscular scoliosis submitted to corrective surgery. Methods  Retrospective cohort study, including pediatric patients diagnosed with neuromuscular scoliosis undergoing instrumentation and posterior vertebral fusion in a university hospital. Patient characteristics were collected from the hospital information system. Results  A total of 39 patients were included in the study. The intraoperative blood losses were 962 ml, representing a loss of 35.63% of the blood volume. In 20 cases, there was a massive blood loss (> 30%) and only 7 patients did not need a transfusion. The group of patients with massive blood loss had a slightly higher age (13.75 versus 13.53 years old), a lower body mass index (BMI) percentile (25 versus 50), and for each decrease of 0.38 in the BMI, intraoperative blood losses increased 1% ( p  < 0.05). The value of preoperative albumin had influence on the percentage of blood loss, and for each decrease of 0.4 of albumin, blood loss increased 1% ( p  < 0.05). Conclusions  The factors that most contributed to the differences in blood loss were age, BMI, and preoperative albumin value. There was no significant association between Cobb angle, number of fusion levels and duration of surgery. We can conclude that these patients would benefit from preoperative nutritional control.

Traumatic Sacral Fractures: Navigation Technique in Instrumented Stabilization

BACKGROUND

Sacral fractures are a challenge regarding treatment and classification. Surgical techniques using spinal navigation systems can improve treatment, especially if used in collaboration among different specialists.

METHODS

Between 2015 and 2017, we treated 25 consecutive cases of sacral fracture. Twelve patients (48%) underwent mechanical ventilation due to hypovolemic shock for severe thoracoabdominal trauma; bleeding was blocked with pelvic packing in 9 cases (36%) and transcatheter embolization in 2 cases (8%). External fixation was used in 7 cases (28%). In 20 cases (80%) spinal fractures were associated. All patients were operated on using spinal navigation by a team of neurosurgeons and orthopedic surgeons.

RESULTS

The mean time from first observation to surgery was 18 days (range 8-31). Surgical treatment consisted of iliosacral fixation in 19 cases (76%) and spinopelvic fixation in 6 cases (24%). The mean number of screws for spinopelvic fixation was 9.67 (range 6-17) with a mean operation time of 323.67 minutes (range 247-471); in iliosacral osteosynthesis the mean screw number was 1.37 (range 1-3) and mean surgical time was 78.93 minutes (range 61-130). Postoperative computed tomography showed the correct screw placement. Wound infection occurred in 2 cases (8%), managed with vacuum-assisted closure therapy; in 1 case (4%) a sacral screw was removed for decubitus.

CONCLUSIONS

Navigation systems in instrumented spinopelvic and sacropelvic reconstruction provide greater safety, reducing learning times and malpositioning. Multidisciplinary management allows us to achieve optimal results, especially when the sacral fracture is combined with spinal and pelvic lesions. The use of navigation systems could represent an important advancement.

Pelvic Obliquity Correction in Distraction-Based Growth Friendly Implants

DESIGN

Multicenter retrospective review.

OBJECTIVE

To evaluate radiographic outcomes and complication rates of patients treated with distraction based implants and pelvic fixation with either screws (sacral-alar-iliac [SAI] screws or iliac screws) or hooks (S hook iliac fixation).

SUMMARY OF BACKGROUND DATA

Multiple options exist for pelvic fixation in distraction-based growing rod systems; however, limited comparative data are available.

METHODS

Early-onset scoliosis (EOS) patients of all diagnoses with distraction-based implants that had pelvic fixation from 2000 to 2013 were reviewed from two EOS multicenter databases. Patients were divided into two groups by type of pelvic fixation: (1) screw group (SAI screws or iliac screws) or (2) S hooks. Exclusion criteria were as follows: index instrumentation ≥10 years old and follow up <2 years. A total of 153 patients met the inclusion criteria. Mean age at index surgery was 6.1 years (range 1.0-9.9 years) and mean follow-up was 4.9 years.

RESULTS

Pelvic fixation in the 153 patients was as follows: screw group = 42 and S hook group = 111. When comparing patients with >20° of initial pelvic obliquity, the screw group had significantly more correction; mean 26° ± 13° for the screw group versus mean 17° ± 7° in the S hook group (p = .039). There was no significant difference in change in T1-S1 length (40 vs. 39 mm, p = .89) or correction of Cobb angle (30° vs. 24°, p = .24). The total complication rate for the screw group was 14% (6/42) versus 25% (28/111) in the S hook group, though this did not achieve significance (p = .25). The most common complications were device migration (13), implant failure (8), and implant prominence (4) for S hooks and implant failure (3), implant prominence (2), and device migration (1) for the screw group.

CONCLUSION

In distraction-based growth-friendly constructs, pelvic fixation with screws achieved better correction of pelvic obliquity than S hooks. Complications were almost twice as common with S hooks than screws, though this did not reach statistical significance.

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.

Scoliosis in Duchenne muscular dystrophy children is fully reducible in the initial stage, and becomes structural over time

BACKGROUND

Patients with Duchenne muscular dystrophy (DMD) often develop scoliosis that progresses rapidly after loss of ambulation. Management of scoliosis is crucial because it affects both life expectancy and quality of life of patients with DMD. Spinal orthosis attempts to prevent or delay scoliosis using spinal support at three points of the controlling mechanism; the curve should be flattened by the pressure. Therefore, it is assumed that spine flexibility could be a significant influencing factor for the effectiveness of braces. Hence, we attempted to investigate the flexibility of scoliosis in non-ambulant patients with DMD.

METHODS

We reviewed the medical records of 273 boys who were genetically identified as having DMD, and finally, 50 boys with serial records of radiographs after loss of ambulation were finally enrolled. And among them, only 31 patients developed scoliosis. Spine radiographs in sitting and supine positions were also reviewed to obtain Cobb angle, curve flexibility, and pelvic obliquity. Flexibilities (%) were calculated by the difference in angles between the sitting and supine positions divided by the angle at the sitting position, multiplied by 100.

RESULTS

Among 31 boys who had scoliosis, all but 2 boys with curves went through a sequential course of 1) no scoliosis, 2) nonstructural scoliosis, when scoliosis was only measurable in the sitting position, and 3) structural scoliosis, when scoliosis was also detectable in the supine position. Flexibility decreased each year after detection of scoliosis in those who developed scoliosis the first year, from 75.5 ± 5.0% to 57.1 ± 10.5% and to 49.1 ± 10.0% (mean ± standard deviation). Spinal flexibility was significantly correlated with curve magnitude of scoliosis in both sitting and supine position (p < 0.05, respectively).

CONCLUSIONS

There is a period of fully reducible curve in DMD patients at the initial stage of scoliosis. Afterward, as spinal curve progresses, flexibility decreases over time. To detect the scoliosis when the curve is fully reducible, scoliosis curve in DMD patients should be evaluated dynamically, including radiographs of at least in two different positions.

USE OF ALAR-ILIAC S2 SCREW TECHNIQUE IN SCOLIOSIS SECONDARY TO MYELOMENINGOCELE

ABSTRACT Objective: To evaluate retrospectively the results related to the use of pelvic fixation with alar-iliac S2 screw in individuals with myelomeningocele. Methods: Retrospective study of cases surgically treated with this technique, between January 2015 and March 2018 at the Pequeno Principe Children's Hospital. Radiographic images and clinical records were analyzed in search of complications. Results: Twelve patients with mean age of 13.3 years were treated at the time of surgery. The mean follow-up was 11.5 months. The mean of the highest magnitude curve measured by the Cobb angle in the preoperative period was 83.8°; while in the last postoperative follow-up was 29.5° (correction of 65%). The mean pelvic obliquity was 23.1° in the preoperative period and in the postoperative was 7.1° (correction of 69%). Only 2 cases (17%) with complications associated with material failure at the level of sacroiliac fixation, due to the unilateral release of the head of the polyaxial S2 iliac screw. Conclusions: The technique of pelvic fixation in the scoliosis secondary to myelomeningocele with the use of S2 alar-iliac screws has shown satisfactory results, with only two complications (17%) directly related to pelvic fixation in the operated cases. Level of Evidence IV; Series of Cases.

Low rates of complications after spinopelvic fixation with iliac screws in 260 adult patients with a minimum 2-year follow-up

OBJECTIVE

Recent literature describing complications associated with spinopelvic fixation with iliac screws in adult patients has been limited but has suggested high complication rates. The authors' objective was to report their experience with iliac screw fixation in a large series of patients with a 2-year minimum follow-up.

METHODS

Of 327 adult patients undergoing spinopelvic fixation with iliac screws at the authors' institution between 2010 and 2015, 260 met the study inclusion criteria (age ≥ 18 years, first-time iliac screw placement, and 2-year minimum follow-up). Patients with active spinal infection were excluded. All iliac screws were placed via a posterior midline approach using fluoroscopic guidance. Iliac screw heads were deeply recessed into the posterior superior iliac spine. Clinical and radiographic data were obtained and analyzed.

RESULTS

Twenty patients (7.7%) had iliac screw-related complication, which included fracture (12, 4.6%) and/or screw loosening (9, 3.5%). No patients had iliac screw head prominence that required revision surgery or resulted in pain, wound dehiscence, or poor cosmesis. Eleven patients (4.2%) had rod or connector fracture below S1. Overall, 23 patients (8.8%) had L5-S1 pseudarthrosis. Four patients (1.5%) had fracture of the S1 screw. Seven patients (2.7%) had wound dehiscence (unrelated to the iliac screw head) or infection. The rate of reoperation (excluding proximal junctional kyphosis) was 17.7%. On univariate analysis, an iliac screw-related complication rate was significantly associated with revision fusion (70.0% vs 41.2%, p = 0.013), a greater number of instrumented vertebrae (mean 12.6 vs 10.3, p = 0.014), and greater postoperative pelvic tilt (mean 27.7° vs 23.2°, p = 0.04). Lumbosacral junction-related complications were associated with a greater mean number of instrumented vertebrae (12.6 vs 10.3, p = 0.014). Reoperation was associated with a younger mean age at surgery (61.8 vs 65.8 years, p = 0.014), a greater mean number of instrumented vertebrae (12.2 vs 10.2, p = 0.001), and longer clinical and radiological mean follow-up duration (55.8 vs 44.5 months, p < 0.001; 55.8 vs 44.6 months, p < 0.001, respectively). On multivariate analysis, reoperation was associated with longer clinical follow-up (p < 0.001).

CONCLUSIONS

Previous studies on iliac screw fixation have reported very high rates of complications and reoperation (as high as 53.6%). In this large, single-center series of adult patients, iliac screws were an effective method of spinopelvic fixation that had high rates of lumbosacral fusion and far lower complication rates than previously reported. Collectively, these findings argue that iliac screw fixation should remain a favored technique for spinopelvic fixation.

Comparison of Sacral-Alar-Iliac and Iliac-Only Methods of Pelvic Fixation in Early-Onset Scoliosis at 5.8 Years' Mean Follow-up

STUDY DESIGN

Retrospective.

OBJECTIVE

Compare clinical outcomes in early-onset scoliosis (EOS) patients treated with sacral-alar-iliac (SAI) versus iliac-only methods of pelvic fixation at two years' minimum follow-up.

SUMMARY OF BACKGROUND DATA

Pelvic fixation in EOS is challenged by poor bone, anchor migration, and displacement. The long-term outcomes of SAI fixation in EOS is unknown.

METHODS

We retrospectively reviewed EOS patients in a single center from 2000 to 2017. Inclusion criteria were posterior spinal instrumentation with pelvic fixation before age 10 and 2 years' minimum follow-up. Clinical and radiographic data were analyzed using chi-squared and Student t tests (significance defined as p <.05).

RESULTS

Seven subjects were included in the iliac-only fixation group (Galveston technique = 2, iliac screws = 5) and 17 in the SAI group. For the iliac-only group (mean follow-up = 6.8 years), pelvic obliquity improved from a mean of 18° at initial presentation to 11° at first instrumentation (p = .096), to 9° at end follow-up (p = .060), whereas the major curve improved correspondingly from a mean of 84° to 50° (p = .002) to 39° (p = .006). For the SAI group (mean follow-up = 5.5 years) at the same time points, pelvic obliquity improved from a mean of 25° to 6° (p <.001) to 5° (p <.001), whereas the major curve improved from a mean of 83° to 38° (p <.001) to 29° (p <.001). SAI fixation was associated with fewer complications (11 complications in 17 patients) compared to iliac-only fixation (10 complications in 7 patients) (p = .04). Neither method was associated with pelvic growth disturbances or neurologic deficits.

CONCLUSIONS

In EOS patients at 2 years' minimum (5.8 years' mean) follow-up, both SAI and iliac-only methods corrected major curve, only SAI fixation corrected pelvic obliquity, and neither was associated with pelvic growth disturbances. SAI fixation was also associated with fewer complications. These findings may be due to the length and direction of the SAI anchors and abutment on the iliac cortex.

LEVEL OF EVIDENCE

Level III.

Radiographic and Clinical Outcomes of Surgical Correction of Poliomyelitis-Related Spinal Deformities: A Comparison Among Three Types of Pelvic Instrumentations

BACKGROUND

We compared the clinical and radiographic outcomes of corrective surgery in patients with poliomyelitis-related spinal deformity (PSD) using 3 types of pelvic fixation and investigated the incidence and risk factors for complications.

METHODS

We reviewed the data from 42 patients with PSD who had undergone spinopelvic reconstruction at a single institution from 2000 to 2016. Of the 42 patients, 15 had been treated with the Galveston technique, 13 with iliac screw fixation, and 14 with S2-alar-iliac (S2AI) screw fixation. Demographic data, radiographic parameters, and complications were analyzed. Health-related quality of life was determined using Scoliosis Research Society (SRS) 22-item questionnaires and the Oswestry Disability Index scores.

RESULTS

After surgery, the correction rate of the main curve was 51.7%, 57.8%, and 52.1% in the 3 groups, with significant improvement in regional kyphosis, coronal balance, and pelvic obliquity (PO) (P < 0.05). The correction of PO was similar among the 3 types of pelvic fixation; however, the patients treated with S2AI fixation required significantly less operative time (P < 0.05) and blood loss (P < 0.006). The overall complication rate was 40.5%, with a major complication rate of 23.8%. Age at surgery (P = 0.006) and grade >2 SRS-Schwab osteotomy (P = 0.036) were significant risk factors for complications. Significant improvement was found in the SRS-22 and Oswestry Disability Index scores at the final follow-up examination in the 3 groups.

CONCLUSIONS

The present study showed satisfactory correction of spinopelvic deformity for 42 patients with PSD. Compared with the Galveston technique and iliac screw fixation, the use of S2AI significantly decrease the operative time and estimated blood loss and obtained similar correction of PO. Patient age at surgery and grade >2 SRS-Schwab osteotomy were significant risk factors for complications.

Pediatric spine imaging post scoliosis surgery

Many orthopedic articles describe advances in surgical techniques and implants used in pediatric scoliosis surgery. However, even though postoperative spine imaging constitutes a large portion of outpatient musculoskeletal pediatric radiology, few, if any, radiology articles discuss this topic. There has been interval advancement over the last decades of the orthopedic procedures used in the treatment of spinal scoliosis in adolescents with idiopathic scoliosis. The goal of treatment in these patients is to stop the progression of the curve by blocking the spinal growth and correcting the deformity as much as possible. To that end, the authors in this paper discuss postoperative imaging findings of Harrington rods, Luque rods, Luque-Galveston implants and segmental spinal fusion systems. Regarding early onset scoliosis, the guiding principles used for adolescent idiopathic scoliosis do not apply to a growing spine because they would impede lung development. As a result, other devices have been developed to correct the curve and to allow spinal growth. These include spine-based growing rods, vertically expandable prosthetic titanium rods (requiring repetitive surgeries) and magnetically controlled growing rods (with a magnetic locking/unlocking system). Other more recent systems are Shilla and thoracoscopic anterior vertebral body tethering, which allow guided growth of the spine without repetitive interventions. In this paper, we review the radiologic appearances of different orthopedic implants and techniques used to treat adolescent idiopathic scoliosis and early onset scoliosis. Moreover, we present the imaging findings of the most frequent postoperative complications.

Analysis of Risk Factors for Major Complications Following Elective Posterior Lumbar Fusion

STUDY DESIGN

Retrospective study of prospectively collected data.

OBJECTIVE

To identify risk factors for the development of any major complication after elective posterior lumbar fusion (PLF).

SUMMARY OF BACKGROUND DATA

PLF is one of the most performed fusion techniques with utilization rates increasing by 356% between 1993 and 2001. Surgical and anesthetic advances have made the option of surgery more accessible for elderly patients with a larger comorbidity burden. Identifying risk factors for the development of major complications after elective PLF is important for patient risk stratification and patient safety efforts.

METHODS

The 2011 to 2014 American College of Surgeon's National Surgical Quality Improvement Program database was queried using Current Procedural Terminology codes 22612, 22630, and 22633. Patients were divided into two cohorts based on the development of any major complication. Bivariate and multivariate logistic regression analyses were employed to identify predictors for the development of ≥ 1, ≥ 2, and ≥ 3 major complications.

RESULTS

A total of 7761 patients met the inclusion criteria for the study of which, 2055 (26.5%) patients developed one major complication, 249 (3.2%) patients developed two major complications, and 151 (1.9%) patients developed three major complications. The most common complication was intra/postoperative red blood cell transfusion (23.2%). Three multivariate logistic regression models were employed to identify factors associated with ≥ 1, ≥ 2, and ≥ 3 major complications. Patient variables present across all three models were osteotomy, pelvic fixation, operation time ≥4 hours, bleeding disorder, and American Society of Anesthesiology Class ≥ 3.

CONCLUSION

Several risk factors were identified for the development of major complications after elective PLF. Identification of these factors can improve the selection of appropriate surgical candidates, patient risk stratification, and patient postoperative safety.

LEVEL OF EVIDENCE

3.

The Fate of the Neuromuscular Hip After Spinal Fusion

BACKGROUND

The goals of treatment of neuromuscular scoliosis are to achieve a balanced spine and level pelvis with most constructs including pelvic fixation. However, the pelvis can become a stiff "end vertebra" that prevents compensatory mechanisms to adjust to hip deformities in this patient population. The purpose of this study is to determine the frequency of hip pathology and surgery after spinal fusion in this patient population.

METHODS

We performed a retrospective chart and radiographic review of cerebral palsy patients who underwent posterior spinal fusion (PSF) at our institution from 2005 to 2011. We collected radiographic data of preoperative and postoperative pelvic obliquity and hip reduction status and position (up, level, down). We further evaluated patients requiring hip surgery (containment or salvage).

RESULTS

Of 47 patients with an average follow-up of 3.5 years after spinal fusion, 21 (45%) underwent a hip procedure. Thirty-eight patients (81%) demonstrated or developed hip subluxation/dislocation. Hip pathology occurred more often in the up hip, but the pathologic down hip more often underwent a hip surgery. Eight new hip subluxation/dislocations occurred after spine surgery. Three (38%) of the new postoperative subluxation/dislocations required hip surgery; all had pelvic obliquity <6 degrees. Eleven patients underwent hip surgery before PSF, 7 were varus femoral osteotomies for subluxation, whereas 5 hips required salvage. In follow-up after PSF, none of these had a new dislocation. Ten patients required hip surgery after PSF at a mean of 1.6 years after PSF. Eight patients had a salvage procedure for painful hip and 2 varus femoral osteotomies for subluxations.

CONCLUSIONS

In our cerebral palsy patients who underwent PSF, 45% of these patients required a hip procedure. In the patients who had containment before PSF, the hips maintained reduction after spinal fixation. After correction of pelvic obliquity, 17% of patients had new-onset hip subluxation/dislocation after PSF. Postoperative subluxation/dislocation was not dependent on whether the hip was up or down preoperatively.

LEVEL OF EVIDENCE

IV, Retrospective.

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

STUDY DESIGN

Single institution cohort data were collected prospectively and reviewed retrospectively.

OBJECTIVES

This 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 DATA

The optimal choice for spinopelvic fixation in CP scoliosis with pelvic obliquity is controversial.

METHODS

Patients 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.

RESULTS

Seventy-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.

CONCLUSIONS

This 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 EVIDENCE

Therapeutic study, Level III.

The radiological assessment of pelvic obliquity in cerebral palsy and the impact on hip development

Pelvic obliquity is a common finding in adolescents with cerebral palsy, however, there is little agreement on its measurement or relationship with hip development at different gross motor function classification system (GMFCS) levels. The purpose of this investigation was to study these issues in a large, population-based cohort of adolescents with cerebral palsy at transition into adult services. The cohort were a subset of a three year birth cohort (n = 98, 65M: 33F, with a mean age of 18.8 years (14.8 to 23.63) at their last radiological review) with the common features of a migration percentage greater than 30% and a history of adductor release surgery. Different radiological methods of measuring pelvic obliquity were investigated in 40 patients and the angle between the acetabular tear drops (ITDL) and the horizontal reference frame of the radiograph was found to be reliable, with good face validity. This was selected for further study in all 98 patients. The median pelvic obliquity was 4° (interquartile range 2° to 8°). There was a strong correlation between hip morphology and the presence of pelvic obliquity (effect of ITDL on Sharpe's angle in the higher hip; rho 7.20 (5% confidence interval 5.59 to 8.81, p < 0.001). This was particularly true in non-ambulant adolescents (GMFCS IV and V) with severe pelvic obliquity, but was also easily detectable and clinically relevant in ambulant adolescents with mild pelvic obliquity. The identification of pelvic obliquity and its management deserves closer scrutiny in children and adolescents with cerebral palsy.

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

STUDY DESIGN

Multicenter prospective database review of patients with cerebral palsy (CP) and spinal deformity.

OBJECTIVE

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.

SUMMARY OF BACKGROUND DATA

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

LEVEL OF EVIDENCE

3.

The History of Spinal Deformity

The description and history of the treatment of spinal disorders have evolved from very early Grecian and Hindu times through to today's complex techniques. An emphasis on renowned figures from throughout the world who have contributed greatly to our understanding and care of spinal deformities is provided. Knowledge of the past provides significant input to our understanding of the current problems and enhances the development of future modalities of care.

Entry zone of iliac screw fixation to maintain proper entry width and screw length

PURPOSE

To evaluate the entry zone of iliac screw fixation to maintain proper entry width and screw length.

METHODS

Computed tomography images of pelvic bones from 90 human cadavers were reconstructed into 3-dimensional models. In each model, a sectional image crossing the posterior superior iliac spine (PSIS) and anterior inferior iliac spine (AIIS) and consecutive sectional images up to 20 mm superiorly and inferiorly from the PSIS with 1-mm intervals aiming the AIIS were obtained. One virtual iliac screw with 10-mm diameter was introduced onto the PSIS at the middle and at the lateral and medial 1/4 points on the prominence of the posterior iliac spine. The entry width of the bony prominence and the corresponding maximal screw length available were evaluated for each entry point.

RESULTS

The entry width was smallest on the inferior 20 mm (4.7 ± 3.0 mm) and gradually increased up to the superior 10 mm (19.1 ± 3.9 mm) sectional images. The maximal screw length was smallest on the superior 20 mm (76.7 ± 39.7 mm) and gradually increased down to the inferior 10 mm (112.3 ± 15.1 mm) sectional images. The maximal screw lengths were significantly greatest at the most medial point and smallest at the most lateral point on the superior 20- and 10-mm sectional images and at the PSIS.

CONCLUSIONS

The iliac screw fixation entry zone to maintain proper screw length and entry width is outlined from 20 mm superiorly to 10 mm inferiorly from the PSIS and is located more medially from the prominence of the posterior iliac spine.

Biomechanical analysis of iliac screw fixation in spinal deformity instrumentation

BACKGROUND

High rates of iliac screw fixation failures have been reported in spinopelvic instrumentations. The objective was to assess the iliac screw loads as functions of instrumentation variables.

METHODS

Spinopelvic instrumentations of six neuromuscular scoliosis were simulated using patient-specific modeling techniques to evaluate the intra- and postoperative iliac screw loads as functions of instrumentation variables: the combined use of sacral screws, the uses of lateral offset connectors and cross-rod connectors, and the iliac screw insertion point and trajectory.

FINDINGS

Sacral screws, lateral connectors and the iliac screw insertion point had significant effects on iliac screw axial forces (69-297N) and toggle moments (0.8-2.9Nm) (p<0.05). The addition of sacral screws made the iliac screw forces lower for some functional loads but higher for other functional loads, and resulted in an increase of intraoperative screw forces when attaching the rods onto these additional screws. When lateral offset connectors were used, the toggle moments were 16% and 25% higher, respectively for the left and right sides. Inserting iliac through the sacrum resulted in 17% lower toggle moment compared to insertion through the iliac crest. Cross-rod connectors had no significant effect on the intraoperative iliac screw forces. Postoperative functional loading had an important effect (additional 34% screw axial force and 18% toggle moment).

INTERPRETATION

It is possible to reduce the iliac screw loads by adapting instrumentation variables and strategies. Reducing the loads could decrease the risk of failure associated with iliac screw fixations.