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.

One-way self-expanding rod for early-onset scoliosis: early results of a clinical trial of 20 patients.

PURPOSE: Progressive early-onset scoliosis raises major challenges for surgeons, as growth must be preserved. With traditional growing rods, the need for repeated surgery is associated with numerous complications, high costs, and heavy psychosocial burden on the patient and family. We assessed the safety and efficacy of a new one-way self-expanding rod (OWSER). METHODS: This prospective single-centre phase 2 study included two groups of children with progressive EOS treated by the OWSER in 2016-2017: Ten received a unilateral construct to treat progressive non-neuromuscular curves and 10 others a bilateral construct for neuromuscular scoliosis. Clinical and radiological data were assessed at surgery and 3, 6, 12, 18 months later. The primary endpoint was success defined as the absence of repeated surgery at 12 months. RESULTS: In the non-neuromuscular group, rod expansion occurred in 5 of 10 patients [95% CI 19-81]; in the five other patients, rotational conflict inside the domino prevented rod expansion, four of them required surgery within the first 12 months. Rod expansion occurred spontaneously and during monthly traction sessions in all 10 neuromuscular patients [95% CI 69-100], without mechanical or device-related complications. Residual pelvic obliquity was improved by -3° [- 6.0 to 9.5] at 18 months. Lung function improved in the non-neuromuscular group. CONCLUSION: In neuromuscular diseases, the OWSER bilateral construct seems to be safe and less aggressive. Used as unilateral construct in non-neuromuscular group, it was less effective. Accordingly, we recommend the bilateral construct for all aetiologies. That device could avoid further surgery and reduce the rate of complications after long follow-up.

Long term results of the revisited Meary closing wedge tarsectomy for the treatment of the fixed cavo-varus foot in adolescent with Charcot-Marie-Tooth disease.

BACKGROUND: Various techniques have been proposed for the treatment of cavovarus feet (CVF). The aim of this study was to report outcomes of the revisited Meary's dorsal closing wedge tarsectomy for fixed CVF secondary to Charcot-Marie-Tooth (CMT) disease. METHODS: All CVF operated on between 1977 and 2011 were included. The tarsectomy design was modified from its original description and systemically combined with a plantar fascia release, a Dwyer osteotomy and a proximal extension osteotomy of the 1st metatarsal bone if required. Outcomes were assessed by 2 functional scores and radiographically. RESULTS: Among the 26 feet (20 patients), the Wicart and Seringe score was very good or good, fair and poor in respectively 58%, 23% and 19% of the feet. Hindfoot and midfoot AOFASs were of 95.5 and 75 respectively. All radiographic measures were significantly improved. CONCLUSIONS: This complete revisited procedure is an efficient and safe surgical technique for the treatment of the CMT disease CVF. LEVEL OF EVIDENCE: Level IV.

3D pre-operative planning and patient-specific guides for re-directional peri-acetabular osteotomy in children and adolescents.

Surgical procedures to correct hip dysplasia associated with subluxation or dislocation of the femoral head are complex. The 3D geometric abnormalities of the acetabulum and proximal femur vary across patients. We, therefore, suggest a patient-specific surgical treatment involving computer-assisted 3D planning of the peri-acetabular osteotomies, taking into account the femoral head position; 3D printing of patient-specific guides for the cuts, repositioning, and fixation; and intra-operative application of the simulated displacements with their fixation. LEVEL OF EVIDENCE: IV.

Long-term outcomes of hip reconstruction surgery in children with GMFCS III diplegic cerebral palsy.

INTRODUCTION: The results of hip reconstruction surgery are known for non-walking (GMFCS IV and V) and walking (GMFCS I and II) patients. Few studies deal with GMFCS III patients in isolation. Their intermediate functional status can be deteriorated by asymmetrical contractures, hip dislocation, multi-level deformities of the lower limbs, leading to motor function degradation, and possibly losing their ability to walk. The aim of our study was to establish whether surgical results were maintained over time and whether the functional status changed. MATERIAL AND METHODS: Fifteen patients with GMFCS III spastic diplegia, treated for hip subluxation, were reviewed. The mean age at the time of surgery was 10 years old. The mean follow-up after surgery was 11 years. Reconstructive surgery was performed on 21 hips including pelvic osteotomy in all cases, with associated femoral osteotomy in 19 cases. Clinical (pain, joint mobility, walking aids, walking distance, GMFCS level) and radiological data (Melbourne Cerebral Palsy Hip Classification, standard coxometry) were recorded preoperatively and at the last follow-up. RESULTS: Preoperatively, 6 patients were losing their ability to walk due to pain and flexion-adduction contracture. At the last follow-up, no patients had pain and joint mobility was improved in all cases. For one patient, recovery to their previous functional state required a period of two years. In the long term, 14 patients were GMFCS III and only one patient was GMFCS IV due to reasons unrelated to hip surgery. The radiological parameters improved significantly. The Melbourne score was IV preoperatively for all patients. At the last follow-up, 10 hips were grade I, 6 hips were grade II and 5 hips were grade III. DISCUSSION: Correction of architectural disorders of the subluxed hip by pelvic osteotomy, in most cases associated with femoral osteotomy, improves functional and radiological status for GMFCS III patients. This improvement is maintained in the long-term. Complementary surgeries correcting the other deformities of the lower limbs were necessary in more than half of the patients. LEVEL OF EVIDENCE: IV.

Rehabilitation After Single-Event Multilevel Surgery for Children and Young Adults With Cerebral Palsy: A Systematic Review.

ABSTRACT: This review sought to describe and analyze published protocols for rehabilitation after single-event multilevel surgery for people with cerebral palsy, to identify their differences and limits, and to introduce a common step-by-step framework for future descriptions and assessments of postoperative rehabilitation protocols.The MEDLINE, Embase, CINAHL, and the Cochrane Library databases were searched. Inclusion criteria were as follows: (1) single-event multilevel surgery, (2) full-text reports published after 1985, and (3) articles with a method section describing the rehabilitation protocol. Interventions were coded using the Oxford Levels of Evidence and the Methodological Index for Non-Randomized Studies Index.Twenty-four articles were included in the review. Studies included patients aged 4-30 yrs with spastic cerebral palsy (hemiplegia, diplegia, and quadriplegia). The mean postoperative rehabilitation duration was 4.5 mos, with 4 sessions per week, and rehabilitation took place in a rehabilitation center. This review provides relevant information about the modalities, contents, limits, and difficulties associated with the post-SEMS rehabilitation protocol reported in the literature. Pain was identified as a major problem.A more precise and comprehensive description of post-SEMS rehabilitation protocols would be useful. The proposed five-step framework could be used by future studies to standardize their protocol description in terms of objective, content, and intensity.

Effect of an augmented reality active video game for gait training in children with cerebral palsy following single-event multilevel surgery: protocol for a randomised controlled trial.

INTRODUCTION: In paediatric rehabilitation, fun and motivation are also critical keys to successful therapy. A variety of interventions have shown positive effects, high level of interest, compliance and engagement with active video game (AVG).This seems to be an interesting approach for the postoperative gait rehabilitation of children with cerebral palsy (CP). In this study, we will investigate if an overground gait training (GT) delivered through an AVG can improve walking capacity and anaerobic performance. METHODS AND ANALYSIS: This study is a randomised clinical controlled trial. A total of 14 children and adolescents in the age of 10-18 years with CP will be included. The minimum time between surgery and inclusion will be 7 weeks. The test group will participate in the GT programme with Augmented Reality Rehabilitation of Walking-Cerebral Palsy AVG, control group will receive GT on a treadmill. The primary outcome is the 6-Min Walk Test assessing walking capacity; secondary outcomes are the Muscle Power Sprint Test for anaerobic performance and Shuttle Run Test for physical fitness level. Satisfaction is tested with the Physical Activity Enjoyment Scale. ETHICS AND DISSEMINATION: The findings will be disseminated by publications in peer-reviewed journals and conferences. This study received agreement from French ethic committee (Comité de Protection des Personnes Sud-Est VI-Number 2020-A02959-30). TRIAL REGISTRATION NUMBER: NCT04837105.

Minimally Invasive Surgery for Neuromuscular Scoliosis: Results and Complications at a Minimal Follow-up of 5 Years.

STUDY DESIGN: A prospective study. OBJECTIVE: The aim of this study was to report the results of an alternative technique to growing rods (GR) for neuromuscular scoliosis using a minimally invasive fusionless surgery with a minimum of 5 years' follow-up. SUMMARY OF BACKGROUND DATA: Conservative treatment is not effective in progressive neuromuscular scoliosis. Early surgery using GR is increasingly advocated to control the deformity while preserving spinal and thoracic growth before arthrodesis. These techniques still provide a high rate of complications. METHODS: The technique relies on a bilateral double rod sliding instrumentation anchored proximally by four hooks claws and distally to the pelvis by iliosacral screws through a minimally invasive approach. The clinical and radiological outcomes of 100 consecutive patients with neuromuscular scoliosis who underwent this fusionless surgery with a minimum follow-up of 5 years were reviewed. RESULTS: 6.5 ±â€Š0.7 years after initial surgery, six patients were lost of follow-up and 11 died of unrelated raison. Of the 83 remaining patients at latest follow-up, mean Cobb angle was stable to 35.0° which correspond to 61% correction of the initial deformation. Mean pelvic obliquity was 29.6° (0.3°-80.0°) preoperatively and 7.2 (0.2°-23.5°) at latest follow-up. Correction of the hyper kyphosis remained stable. Skeletal maturitywas reached in 42 of 83 patients (50.6%). None of these patients has required spinal fusion. The global complication rate was 31.3%. CONCLUSION: The outcomes of this minimally invasive fusionless technique at 5 years follow-up showed a stable correction of spinal deformities and pelvic obliquity over time, with a reduced rate of complication. The arthrodesis was not required for all patients at skeletal maturity. This technique could be a good alternative to arthrodesis for neuromuscular scoliosis.Level of Evidence: 3.

Spinopelvic fixation with iliosacral screws in neuromuscular spinal deformities: results in a prospective cohort of 62 patients.

PURPOSE: The results of a prospective series of 62 patients treated for neuromuscular spinal deformities with spinopelvic fixation using iliosacral screws are presented and discussed. METHODS: Sixty-two consecutive patients diagnosed with neuromuscular disorders were prospectively included. Pelvic obliquity and other angular parameters were measured. RESULTS: Mean age was 15.2 years (11.9 to 19.2 years). Spinal deformity was a thoracolumbar curve in 36 cases, a lumbosacral curve in 14 cases, a lumbar curve in four cases, and a combined thoracic and lumbar curve in eight cases. Lumbo-pelvic correction was done using two different strategies. In 15 patients with a normal frontal spinopelvic balance, the two rods were extended directly down to the iliosacral screws. In 47 patients with pelvic obliquity, iliosacral screws were linked to two short rods. The correction was then corrected by distraction and contraction maneuvers applied between the long and short rods. Postoperative angular parameters showed a good correction of spinal deformity in both groups. Patients with preoperative pelvic obliquity had a satisfactory and stable correction at final follow-up. CONCLUSIONS: The technique of pelvic fixation using iliosacral screws and connectors reduce difficulties and operative time due to the complicated three-dimensional bending of the rods for proper placement within the ilium. In patients with preoperative pelvic imbalance, a powerful pelvic anchorage as the iliosacral fixation allowed to use intraoperative reduction maneuvers. Despite the high rate of infectious complications in our patients, we think that our technique provided effective and improved spinal correction for patients with neuromuscular scoliosis.

Proximal femoral osteotomy in neurologic pediatric hips using the locking compression plate.

BACKGROUND: Proximal femoral osteotomy (PFO) is a widely performed reconstructive surgery in pediatric patients with diagnosis of neurologic abnormalities. Many implants have been used for the fixation of these osteotomies. These devices have been evolved to provide stable fixation. A novel fixation system, the proximal femoral locking compression plate (LCP), which has a low lateral profile system, has been developed to address the problem of loosening in the osteoporotic bone, and to reach a more precise angular reduction and fixation stability through the use of locking screws. In this study, we report the surgical technique and results of PFO in children with a neurologic diagnosis. METHODS: Fifty-two children with a primary neurologic diagnosis had a femoral osteotomy with the LCP device. Clinical records and radiographs, neck-shaft angle (NSA), acetabular slope, the Reimer migration percentage, and healing of the osteotomy site were studied. Among the 70 operated hips, 59 operated hips had a follow-up superior to 1 year and were included in this study. RESULTS: Among the 59 operated hips, 25 operated hips presented with subluxations. NSA improved from 145 degrees (130 degrees to 165 degrees) to 120 degrees (110 degrees to 125 degrees) and to 125 degrees (115 degrees to 130 degrees) on last follow-up. The Reimer migration percentage improved from 60% (35% to 90%) to 25% (15% to 35%). Ten operated hips presented with dislocations. Their NSA improved from 150 degrees (145 degrees to 170 degrees) to 122 degrees (115 degrees to 125 degrees) and to 125 degrees (118 degrees to 130 degrees) at last follow-up. The stability of the operative reduction was maintained and full range of motion was preserved. Five operated hips presented with dysplastic hips with NSA>130 degrees without associated subluxation, 6 operated hips presented with windswept deformities, 10 operated hips presented with excessive femoral anteversion, and 3 operated hips presented with pseudarthrosis after earlier PFO were also treated and neither presented angular loosening at last follow-up. No major complications were observed. CONCLUSIONS: The LCP system may be used for a wide range of indications if precise preoperative planning was achieved. Rigid primary fixation allows early mobilization and weight bearing in ambulant patient. LEVEL OF EVIDENCE LEVEL IV: Therapeutic study investigating the results of a treatment studying a case series.

Kinematics after unilateral femoral derotation osteotomy in children with diplegic cerebral palsy.

INTRODUCTION: Femoral derotation osteotomy (FDO) is a treatment option in children and adolescents with cerebral palsy who have transverse plane deviations in their lower limbs. When the transverse kinematic deviations are asymmetric, the osteotomy indication can be unilateral. HYPOTHESIS: Unilateral FDO has a kinematic effect on ipsilateral transverse plane deviations along with those of the pelvis and contralateral side. MATERIALS AND METHODS: Among the 170 diplegic children that our team has operated on, 34 underwent unilateral FDO. Their mean age was 12.5±2.7 years; 12 were GMFCS level I and 22 were level II. The kinematic changes 18 months after surgery were evaluated with a paired Student's t test and correlations were determined with the Spearman test (p<0.05). The mean preoperative femoral anteversion was 45°±8°. In terms of kinematics, on the operated side, the children had a mean internal hip rotation of 26°±7°, external pelvis rotation of -8°±6° and inward foot progression angle of 8°±12°. RESULTS: The anteversion was corrected surgically by -28°±5°. Postoperatively, the ipsilateral hip rotation (10°±10°), pelvis rotation (-2°±5°) and foot rotation (6°±12°) were significantly improved. No correlations were identified between the resulting kinematic parameters and surgical correction. The five feet that had inward rotation (13°±9°) were improved to (-5°±7°). DISCUSSION: Unilateral FDO of the hip in patients with asymmetry not only reduces the internal rotation of the operated hip, it also normalizes the rotation of the pelvis and both feet. However, these improvements are not directly related to the amount of surgical correction. LEVEL OF EVIDENCE: IV: case series.

Surgical treatment of idiopathic pes planovalgus in paediatric patients.

Idiopathic pes planus is common and usually physiologic. Decompensation, when it occurs, may be obvious or on the contrary difficult to identify, raising challenges in patient selection for surgical treatment. The physical examination of a child with pes planus must include an evaluation in the supine position, which helps to adjust the amount of correction during surgery. The many reported surgical procedures include repositioning (talus-reseating, subtalar implants and calcaneo-stop screw), osteotomies and joint fusions. The primary treatment goal is to achieve full architectural correction of the deformity. Selection of the procedure depends on patient age and reducibility of the deformity. The joint lines should be preserved whenever possible. Triceps surae contracture should be sought and corrected if found.

Minimally Invasive Surgery for Neuromuscular Scoliosis: Results and Complications in a Series of One Hundred Patients.

STUDY DESIGN: A retrospective review. OBJECTIVE: To report the results of an alternative technique using a minimally invasive fusionless surgery. The originality is based on the progressive correction of the deformities with proximal and distal fixation and on the reliability of the pelvic fixation using iliosacral screws on osteoporotic bones. SUMMARY OF BACKGROUND DATA: Spinal deformities are common in neuromuscular diseases. Conventional treatment involves bracing, followed by spinal instrumented fusion. Growing rod techniques are increasingly advocated but have a high rate of complications. METHODS: The technique relies on a bilateral double rod sliding construct anchored proximally by four hooks claws and distally to the pelvis by iliosacral screws through a minimally invasive approach. Hundred patients with neuromuscular scoliosis underwent the same fusionless surgery extended from T1 to the pelvis. The average age at initial surgery was 11 + 6 years. Diagnoses included cerebral palsy (61), spinal muscular atrophy (22), muscular dystrophy (10), and other neurological etiologies (7). Cobb angle and pelvic obliquity were measured before and after initial surgery, and at final follow-up. Complications were reviewed. RESULTS: At latest follow-up 3 + 9 years (range 2 yr-6 + 3 yr), the mean Cobb angle improved from 89° to 35° which corresponds to 61% correction. Mean pelvic obliquity improved from 29° to 5°, which corresponds to 83% correction. Mean T1-S1 length increased from 30.02 to 37.28 cm. Mean preoperative hyper kyphosis was reduced from 68.44° to 33.29°. Complications occurred in 26 patients including mechanical complications (12) and wound infections (16). No arthrodesis was required at last follow-up. CONCLUSION: This original fusionless technique is safe and effective, preserving spinal and thoracic growth. It provides a significant correction of spinal deformities and pelvic obliquity with a reduced complications rate. The strength and stability of this modular construct over time allow the avoidance of final arthrodesis. LEVEL OF EVIDENCE: 4.

Sacral and lumbar-pelvic morphology in high-grade spondylolisthesis.

Numerous authors have stressed the importance of posterior arch, vertebral bodies, and intervertebral disk dysplastic changes in lumbosacral spondylolisthesis. An extensive morphologic analysis was conducted of the lumbosacral junction in a series of 100 consecutive patients presenting with severe lumbosacral spondylolisthesis. Statistical correlations were found between the pelvic incidence, sacral slope, and pelvic tilt, as found in healthy volunteers. A statistical relationship exists between the lumbosacral kyphosis and pelvic parameters that explains the global sagittal "balance" of this pathological posture. A well-defined morphological criterion, the "S1 index," strongly correlated with the severity and stiffness of lumbosacral spondylolisthesis.

Predicting postoperative gait in cerebral palsy.

In this work, postoperative lower limb kinematics are predicted with respect to preoperative kinematics, physical examination and surgery data. Data of 115 children with cerebral palsy that have undergone single-event multilevel surgery were considered. Preoperative data dimension was reduced utilizing principal component analysis. Then, multiple linear regressions with 80% confidence intervals were performed between postoperative kinematics and bilateral preoperative kinematics, 36 physical examination variables and combinations of 9 different surgical procedures. The mean prediction errors on test vary from 4° (pelvic obliquity and hip adduction) to 10° (hip rotation and foot progression), depending on the kinematic angle. The unilateral mean sizes of the confidence intervals vary from 5° to 15°. Frontal plane angles are predicted with the lowest errors, however the same performance is achieved when considering the postoperative average signals. Sagittal plane angles are better predicted than transverse plane angles, with statistical differences with respect to the average postoperative kinematics for both plane's angles except for ankle dorsiflexion. The mean prediction errors are smaller than the variability of gait parameters in cerebral palsy. The performance of the system is independent of the preoperative state severity of the patient. Even if the system is not yet accurate enough to define a surgery plan, it shows an unbiased estimation of the most likely outcome, which can be useful for both the clinician and the patient. More patients' data are necessary for improving the precision of the model in order to predict the kinematic outcome of a large number of possible surgeries and gait patterns.

Rectus femoris transfer and musculo-skeletal modeling: effect of surgical treatment on gait and on rectus femoris kinematics.

Spasticity of the rectus femoris (RF) is one of the possible causes of stiff knee gait (SKG) in cerebral palsy. Musculoskeletal studies have shown that in SKG, length and speed of the RF are affected. No evaluation had been made to quantify the modifications of those parameters after surgery. The effect of this operation on gait quality and on RF kinematics was assessed in this study in order to identify kinematic patterns that may aid its diagnosis. For 26 transfers, clinical gait analysis pre- and post-surgery was used to compute the Gait Deviation Index (GDI) and Goldberg's index. The kinematics of the Original RF path (ORFp) was studied before and after surgery. The expression ORFp was chosen to avoid any confusion between this modeling parameter, whose computation was unchanged, and the actual anatomical path that was modified by surgery. The gait quality was improved (+18±12GDI) and there was an inverse relation between the pre-operative GDI and its improvement. The Golberg's index was improved (88% of the cases). The operation had a significant effect on the normalization of the timings of maximum length and speed of the ORFp. The improvement of SKG was correlated with the normalization of the timing of the ORFp's maximum length. The global improvement of the gait quality and of the SKG was demonstrated. Some parameters of muscular kinematics (RF length and velocity) have been standardized, showing an effect of the transfer not only during the swing, but also during stance. The premature timing of the ORFp peak length has been identified as a prognostic factor of a successful surgical outcome.

The convex wrapping algorithm: a method for identifying muscle paths using the underlying bone mesh.

Associating musculoskeletal models to motion analysis data enables the determination of the muscular lengths, lengthening rates and moment arms of the muscles during the studied movement. Therefore, those models must be anatomically personalized and able to identify realistic muscular paths. Different kinds of algorithms exist to achieve this last issue, such as the wired models and the finite elements ones. After having studied the advantages and drawbacks of each one, we present the convex wrapping algorithm. Its purpose is to identify the shortest path from the origin to the insertion of a muscle wrapping over the underlying skeleton mesh while respecting possible non-sliding constraints. After the presentation of the algorithm, the results obtained are compared to a classically used wrapping surface algorithm (obstacle set method) by measuring the length and moment arm of the semitendinosus muscle during an asymptomatic gait. The convex wrapping algorithm gives an efficient and realistic way of identifying the muscular paths with respect to the underlying bones mesh without the need to define simplified geometric forms. It also enables the identification of the centroid path of the muscles if their thickness evolution function is known. All this presents a particular interest when studying populations presenting noticeable bone deformations, such as those observed in cerebral palsy or rheumatic pathologies.

Lumbar hyperlordosis of neuromuscular origin: pathophysiology and surgical strategy for correction.

Lumbar hyperlordosis of neuromuscular origin is rare and requires surgical treatment in order to preserve a good sitting posture. We report twenty-seven cases of a preponderantly sagittal hyperlordosis deformity of the lumbar spine in patients with neuromuscular disorders and identify the indications and results of treatment. Seventeen males and ten females, aged 13 to 27 years, underwent operations for a lumbar hyperlordosis of neuromuscular origin responsible for major difficulties in sitting. In all patients, the sacrum was horizontal and associated in twenty-six cases with marked pelvic anteversion. Eleven patients were treated surgically by a posterior approach. The sixteen remaining patients had a preliminary discectomy, followed by posterior correction and fusion. Lumbar hyperlordosis was reduced from 8 degrees to 77 degrees between L1 and S1. The horizontal sacrum was partially reduced with an improvement from 8 degrees to 50 degrees . Consequently, patients recovered a comfortable sitting position. One patient died of respiratory complications six weeks after surgery. Surgical correction is a demanding procedure which can be performed by a posterior approach. It is mandatory to analyse the spino-pelvic balance to avoid iliac retroversion and the loss of the role of the ischia in the sitting position.