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Background Rib head dislocation (RHD) in dystrophic scoliosis of type 1 neurofibromatosis (DS-NF1) is a unique disorder caused by skeletal dystrophy and scoliotic instability. No particular surgical manipulation is mentioned in the literature to instruct the spine surgeons to effectively obtain more migration of the dislocated rib head without resection. The present study aimed to investigate the effectiveness of screw/hook insertion at vertebrae with RHDs on the retraction of penetrated rib head from spinal canal. Methods 37 neurologically intact patients with DS-NF1 and concomitant 53 RHDs undergoing scoliosis surgery without rib head excision were retrospectively reviewed. We used pre and postoperative whole-spine radiographs to determine the Cobb angle and the vertebral translation (VT), and the CT scans to evaluate the intraspinal rib length (IRL) and rib-vertebral angle (RVA). The dislocated ribs were assigned into two groups according to the presence of screw/hook insertion at vertebrae with RHD: screw/hook group and non-screw/hook group. Results 37 dislocated ribs with screws/hooks insertion at corresponding vertebrae were assigned into the screw/hook group and the remaining 16 dislocated ribs consisted of the non-screw/hook group. In the screw/hook group, the correction rates of Cobb angle and VT were significantly higher than the non-screw/hook group after surgery (58.7 ± 16.0% vs. 30.9 ± 12.4%, p = 0.003; 61.8 ± 18.8% vs. 35.1 ± 16.6%, p = 0.001; respectively). Similarly, more correction rates of IRL and RVA were found in the screw/hook group than the non-screw/hook group (63.1 ± 31.3% vs. 30.1 ± 20.7%, p = 0.008; 17.6 ± 9.7% vs. 7.2 ± 3.6%, p = 0.006; respectively). Multiple linear regression analysis revealed that the correction rates of Cobb angle, VT and RVA contributed significantly to correction of IRL (β = 0.389, 0.939 and 1.869, respectively; p = 0.019, 0.001 and 0.002, respectively). Conclusion Screw/hook insertion at dystrophic vertebrae with RHDs contributed significantly to the degree of retraction of penetrated rib head from spinal canal. This effectiveness is mediated by more corrections of VT and RVA.

To comprehensively present the clinical characteristics and treatment strategies in patients with scoliosis secondary to ganglioneuroma (S-GN).Six patients with S-GN treated surgically at a median age of 12 years were retrospectively reviewed and the median follow-up period was 6 years (4-14 years). The radiological features of GN and the associated scoliosis were evaluated. The surgical strategies and the corresponding outcomes were investigated.All patients had a delayed diagnosis age of GN than scoliosis (12 vs. 9 years). GN was located at the posterior mediastinum in four patients (66.7%) and at retroperitoneum in two, respectively. Tumor occupancies were frequently detected on the X-ray films for four patients (66.7%), being uniformly on the convexity of the main curve. All patients complained of rapid progressive deformities during the growth period. Five patients (83.3%) received total tumor resections, one accepted partial resection. Deformity correction was implemented for all patients with an average rate of 66.4% on the main curve. No recurrence of the GN was detected for all totally tumor-resected patients at the latest follow-up.S-GN is often misdiagnosed clinically. Paravertebral mass neighboring the apex of scoliosis can be meticulously detected from the X-ray films. Total tumor resection should be aggressively performed if possible. The deformity correction could be satisfactorily obtained and the risk of recurrence of the GN was relatively low.

Background. Rib head dislocation (RHD) in dystrophic scoliosis of type 1 neurofibromatosis (DS-NF1) is a unique disorder caused by skeletal dystrophy and scoliotic instability. No particular surgical manipulation is mentioned in the literature to instruct the spine surgeons to effectively obtain more migration of the dislocated rib head without resection. The present study aimed to investigate the effectiveness of screw/hook insertion at vertebrae with RHDs on the retraction of penetrated rib head from spinal canal.Methods. 37 neurologically intact patients with DS-NF1 and concomitant 53 RHDs undergoing scoliosis surgery without rib head excision were retrospectively reviewed. We used pre and postoperative whole-spine radiographs to determine the Cobb angle and the vertebral translation (VT), and the CT scans to evaluate the intraspinal rib length (IRL) and rib-vertebral angle (RVA). The dislocated ribs were stratified into two groups according to the presence of screw/hook insertion at vertebrae with RHD: screw/hook group and non-screw/hook group. Results. 37 dislocated ribs with screws/hooks insertion at corresponding vertebrae were assigned into the screw/hook group and the remaining 16 dislocated ribs consisted of the non-screw/hook group. In the screw/hook group, the correction rates of Cobb angle and VT were significantly higher than the non-screw/hook group after surgery (58.7±16.0% vs. 30.9±12.4%, p=0.003; 61.8±18.8% vs. 35.1±16.6%, p=0.001; respectively). Similarly, more correction rates of IRL and RVA were found in the screw/hook group than the non-screw/hook group (63.1±31.3% vs. 30.1±20.7%, p=0.008; 17.6±9.7% vs. 7.2±3.6%, p=0.006; respectively). Multiple linear regression analysis revealed that the correction rates of Cobb angle, VT and RVA contributed significantly to correction of IRL (β=0.389, 0.939 and 1.869, respectively; p=0.019, 0.001 and 0.002, respectively).Conclusion. Screw/hook insertion at dystrophic vertebrae with RHDs contributed significantly to the degree of retraction of penetrated rib head from spinal canal. This effectiveness is mediated by more corrections of VT and RVA.

Background. There was a paucity of valid information on how to discriminate between different patterns of convex coronal imbalance (CCI>3cm) in dystrophic scoliosis secondary to Type I neurofibromatosis (DS-NF1), while aggravated postoperative CCI occurred regularly with the causes being insufficiently investigated. We aimed to develop a new classification of CCI in DS-NF1, and to optimize the coronal rebalancing strategies.Methods. NF1-related scoliosis database was reviewed and different types of CCI were identified, and the outcomes of coronal rebalance were analyzed. Results. Two main CCI patterns were defined: thoracic CCI (Type 1) and thoracolumbar/lumbar CCI (Type 2), and were further subtyped by the compensatory behavior of the upper hemi-curve (straight or curved morphology). The incidence of immediate post-op CCI was 0.0% and 63.6% for Type1 and Type 2 groups, respectively. Mismatch of both translation and inclination correction between the upper and lower hemi-curve was significant in the post-op coronal imbalanced group (△Upper Arc Translation/△Lower Arc Translation: 109.6±60.0% vs. 31.8±34.4%, p=0.008; △Upper Arc Inclination/△Lower Arc Inclination: 89.8±36.6% vs. 33.5±37.3%, p=0.012). Multiple linear regression analysis revealed that △UAT/△LAT significantly correlated with the correction of coronal balance distance (β=-21.567; p=0.018). A surgical rebalancing algorithm was proposed to treat each subtype.Conclusion. Thoracolumbar/lumbar CCI in dystrophic scoliosis was prone to suffer high risk of persistent post-op CCI. Satisfying coronal rebalance should rely on maximal translational correction of lower hemi-curve, while the upper hemi-curve played the role of fine-tuning for coronal realignment rather than radical Cobb correction, straight morphology in particular.

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 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.