Both structural damage and inflammation of the lumbar spine contribute to the sagittal imbalance in ankylosing spondylitis patients with thoracolumbar kyphosis.

BACKGROUND: The relationship between structural damage and inflammation of the spine and the sagittal imbalance in ankylosing spondylitis (AS) is not well understood. The present study aimed to investigate the correlation between structural damage and inflammation of the lumbar spine and the sagittal imbalance in AS patients with thoracolumbar kyphosis. METHODS: Forty-five AS patients with thoracolumbar kyphosis were retrospectively reviewed. Six sagittal spinal parameters, including the C7 tilt (C7T), spino-sacral angle (SSA), global kyphosis (GK), the sagittal vertical axis (SVA), thoracic kyphosis (TK), and lumbar lordosis (LL), were measured. Structural damage of the lumbar spine was assessed by the modified Stoke AS Spine Score (mSASSS) on radiographs. Lumbar spinal inflammation was evaluated by the AS spinal magnetic resonance imaging (MRI) activity (ASspiMRI-a) on MRI. Correlation analysis was performed using the paired sample t-test. Multivariable linear regression models were constructed to analyze the contributions of mSASSS and ASspiMRI-a to the sagittal parameters. RESULTS: The average values of the sagittal parameters C7T, SSA, GK, SVA, TK, and LL were 68.1°, 80.1°, 77.3°, 168.7 mm, 47.7°, and -0.7°, respectively. The average mSASSS and ASspiMRI-a scores were 9.8 and 10.8, respectively. Correlation analysis showed that the mSASSS and ASspiMRI-a were correlated with C7T, SSA, SVA, and LL (the Spearman correlation coefficients were -0.439, -0.390, 0.424, and 0.530 for mSASSS; -0.406, -0.402, 0.378, and 0.486 for ASspiMRI-a; P<0.05). The C7T, SSA, and SVA were significantly correlated with LL (r=-0.696, -0.779, and 0.633, respectively; P<0.05). There was a weak correlation between the mSASSS and ASspiMRI-a (ß=0.299, P=0.046). The multivariable regression models indicated that the sagittal imbalance was determined to a greater extent by the mSASSS than ASspiMRI-a (the ß values were -1.550 vs. -0.649 for C7T, -1.865 vs. -1.231 for SSA, 9.161 vs. 3.823 for SVA, and 3.128 vs. 1.717 for LL). CONCLUSIONS: Both structural damage and inflammation of the lumbar spine contributed to the sagittal imbalance in AS patients with thoracolumbar kyphosis. In the late stages of AS, the sagittal imbalance was more attributable to the structural damage than the inflammation of the lumbar spine.

Curve Characteristics and Response of Sciatic and Olisthesis Scoliosis Following L5/S1 Transforaminal Lumbar Interbody Fusion in Adolescent Lumbar Spondylolisthesis.

BACKGROUND: Lumbosacral spondylolisthesis-induced scoliosis is a rare clinical entity. Sagittal reconstruction and the coronal curve evolution after surgery for spondylolisthesis have not been investigated in depth. OBJECTIVE: To compare the curve characteristics between sciatic scoliosis and olisthetic scoliosis and to further investigate the effects of lumbosacral transforaminal lumbar interbody fusion (TLIF) on scoliosis evolution. METHODS: Adolescents with sciatic scoliosis group (SS group) or olisthetic scoliosis group (OS group) who underwent L5/S1 TLIF from 2010 to 2017 and were followed up for at least 2 yr were retrospectively reviewed. Radiographic parameters and patient-reported outcomes were evaluated. RESULTS: There were 20 patients in the SS group (M/F: 8/12; age: 15.6 ± 2.2 yr) and 16 in the OS group (M/F: 6/10; age: 16.8 ± 2.5 yr). Both groups had similar preoperative Cobb angles, but more patients with coronal imbalance were observed in the SS group. Moreover, the OS group showed significantly larger L5 tilt and rotation. After surgery, the slip reduction rate of the SS group and OS group were 76.1% ± 12.4% and 79.4% ± 9.6%, respectively. Scoliosis resolution was observed in all patients in the SS group but only in 9 patients (56.2%) in the OS group. Patients with failed scoliosis resolution in the OS group were older and had a larger Cobb angle and L5 rotation compared with those with successful scoliosis resolution. CONCLUSION: Lumbosacral TLIF can achieve satisfactory slip reduction and scoliosis resolution. Sciatic scoliosis often presents with coronal imbalance but also a preferable curve prognosis. A large Cobb angle and L5 rotation may hinder the resolution of olisthetic scoliosis.

Under-contouring of rods: a potential risk factor for proximal junctional kyphosis after posterior correction of Scheuermann kyphosis.

OBJECTIVE: Scheuermann kyphosis (SK) could require surgical treatment in certain situations. A posterior reduction is the most widespread treatment so far, although the development of proximal junctional kyphosis (PJK) is one of the possible complications of this procedure. The contour of the proximal part of the rod could influence the occurrence of PJK in SK patients. The objective of this study was to analyze the impact of the proximal rod contour on the occurrence of a PJK complication in SK patients. METHODS: This retrospective monocentric study was performed in the Nanjing Spine Surgery Department. All eligible patients had undergone posterior correction surgery with pedicle screws only between 2002 and 2017 and had at least 24 months of follow-up. The presence of PJK was quantified on radiographs using the proximal junctional angle (PJA > 10° at the last follow-up). The authors propose a new radiological parameter to measure the angulation of the proximal part of the instrumentation: the proximal contouring rod angle (PCRA) is the angle between the upper endplate of the upper instrumented vertebra (UIV) and the lower endplate of the second vertebra caudal to the UIV. The patients were analyzed according to the presence or absence of PJK. A t-test, receiver operating characteristic (ROC) curve analysis, and logistic regression analysis were performed for statistical analysis. RESULTS: Sixty-two patients treated for SK were included in this study. The mean age was 18.6 ± 8.5 years, and the mean follow-up was 42.5 ± 16.4 months. The mean correction rate of global kyphosis was 46.4% ± 13.7%. At the last follow-up, 17 patients (27.4%) presented with PJK. No significant difference was found between the PJK and non-PJK groups in terms of age and other preoperative variables. A significant difference in the postoperative PCRA was found between the PJK and non-PJK groups (8.2° ± 4.9° vs 15.7° ± 6.6°, respectively; p = 0.001). A postoperative PCRA less than 10.1° predicted a significantly higher risk for PJK (p = 0.002, OR 2.431, 95% CI 1.781-4.133). CONCLUSIONS: Under-contouring of the proximal part of the rods (lower than 10°) is a risk factor for PJK after posterior correction of SK.

Does Vertebral End Plate Morphology Affect Cage Subsidence After Transforaminal Lumbar Interbody Fusion?

OBJECTIVE: To investigate the effect of end plate morphology on cage subsidence and to compare the surgical outcomes among patients with different vertebral end plate morphologies. METHODS: We reviewed a series of consecutive patients from January 2009 to January 2016 who had undergone monosegment L4/5 transforaminal lumbar interbody fusion (TLIF) with a follow-up >2 years. The enrolled patients were divided into 3 groups based on the preoperative vertebral end plate morphology on T1-weighed sagittal magnetic resonance scans: concave group (C group), flat group (F group), and irregular group (Ir group). Lumbar lordosis (LL), segmental lordosis (SL), and disc height (DH) were measured on the plain image at each follow-up, and three-dimensional computed tomography (3D-CT) was obtained at 1 year follow-up to evaluate the cage subsidence and solid fusion. RESULTS: A total of 145 consecutive patients (41 males and 104 females) were included in this study, with a mean follow-up of 33.8 ± 12.3 months. The age was significantly older in the Ir group than in the C group or F group (P < 0.05). Cage subsidence was detected in 23 patients (15.9%) at 1 year follow-up through 3D-CT. The incidence of cage subsidence was significantly higher in the Ir group than in the F group or C group (P < 0.05). Patients in the Ir group had significant loss of DH, SL, and LL at the latest follow-up, compared with those in the C group and F group (P < 0.05). Patients with cage subsidence had a significantly older age (P < 0.05). The presence of cage subsidence was associated with end plate morphology as shown by logistic regression analysis (P < 0.05). Before surgery, Oswestry Disability Index and visual analog scale back pain scores were significantly higher in the Ir group than in the C and F groups (P < 0.05). After surgery and until the latest follow-up, each group experienced significant improvement in contrast to preoperative scores regardless of end plate morphology (P < 0.05). CONCLUSIONS: Morphology of the end plate plays an important role in the development of cage subsidence after TLIF surgery. Fused segments with irregular end plates are prone to cage subsidence. Although cage subsidence does not affect short-term clinical outcomes, measures should be taken to prevent cage subsidence-related loss of SL and total LL.

Sagittal reconstruction of lumbosacral contiguous double-level spondylolytic spondylolisthesis: a comparison of double-level and single-level transforaminal lumbar interbody fusion.

BACKGROUND: Contiguous double-level lumbar spondylolytic spondylolisthesis is an extremely rare condition. There is a paucity of data of lumbosacral deformity and sagittal spino-pelvic malalignment among these patients. Moreover, the effect of transforaminal lumbar interbody fusion (TLIF) on sagittal realignment still remains largely unknown. The aim of the study is to investigate the reconstruction of sagittal alignment and the improvement of clinical outcomes after posterior instrumented double-level or single-level TLIF. METHODS: From January 2010 to September 2018, the records of patients with contiguous L4/5 and L5/S1 double-level spondylolytic spondylolisthesis were retrospectively reviewed. Patients who had undergone double-level or single-level TLIF and a minimum of 2 years' follow-up were included. The slippage parameters and spino-pelvic parameters were measured preoperatively, postoperatively, and at the latest follow-up. RESULTS: A total of 58 patients (21 males and 37 females, mean age of 57.1 ± 6.9 years) were enrolled. Thirty-eight patients were treated with double-level TLIF and the remaining 20 with single-level TLIF (L4/5 in 14; L5/S1 in 6). After surgery, the spondylolisthesis was significantly reduced at both L4/5 and L5/S1 level (all P < 0.001). There was a significant reduction in pelvic tilt (P < 0.001) and a significant increase in sacral slope (P < 0.001). Significant increase in L4-S1 height (P < 0.001) and L4-S1 lordosis (P = 0.012) and decrease in L5 slope (P = 0.004) and L5 incidence (P = 0.001) were also observed. Compared to single-level TLIF, double-level TLIF increased L4-S1 height (P < 0.001) and L4-S1 lordosis (P < 0.001) and reduced L4-SVA (P = 0.007) and L5 incidence (P = 0.013) more obviously, and the sagittal balance was better corrected in double-level TLIF group (P = 0.006). Double-level TLIF group showed larger increase in VAS scores for low back pain. The incidence of implant-related complications was lower in the double-level group. CONCLUSION: Posterior short-segment instrumented TLIF can bring favorable radiographic and clinical outcomes in patients with lumbosacral contiguous double-level spondylolytic spondylolisthesis. Double-level TLIF is more efficient to improve L4-S1 height, regional lumbar lordosis, and global sagittal balance.

Spinal Gorham-Stout syndrome: radiological changes and spinal deformities.

BACKGROUND: Gorham-Stout syndrome (GSS) involving the spine is a rare clinical entity, and there is a paucity of comprehensive study on its radiological features. We aimed to present the radiological changes and spinal deformities in patients with spinal GSS. METHODS: From January 2005 to December 2017, 11 consecutive GSS patients with spinal deformity were identified. Their medical records and imaging features were retrospectively reviewed. Computed tomography (CT) and magnetic resonance imaging (MRI) were used for a precise evaluation of spinal involvement. Posteroanterior and lateral standing radiographs were used to evaluate the spinal deformity. RESULTS: CT showed multi-level generalized osteolytic lesions, with ill-defined fluid attenuation adjacent to the osseous changes. MRI demonstrated hyperintense signals on both T1- and T2-weighted images, while the unaffected segments showed normal signal intensity. Seven patients (63.6%) had a dominant feature of kyphosis, and 4 (36.4%) had scoliosis when spinal GSS was diagnosed. Kyphosis variably spanned from C7 to L1, averaged 94° (range, 53° to 158°), and was associated with sagittal imbalance in 4 cases. In our series, the apex of kyphosis and scoliosis coincided within the most seriously osteolytic segment. All patients received medication for GSS. Two adolescents taking Boston braces showed a relatively stable deformity. Four patients received long posterior spinal fusion, but two had fusion failure. CONCLUSIONS: CT and MRI investigations are important in the initial diagnosis and continued management for spinal GSS. A typical spinal deformity secondary to GSS presents as kyphosis or kyphoscoliosis, which is usually highly variable but highly concordant with osteolysis in terms of span and apex.

Vertebra-disc ratio as a new predictor for curve progression in early thoracic AIS with bracing treatment.

OBJECTIVES: Previous studies have reported various predictors for curve progression in braced adolescent idiopathic scoliosis (AIS) patients. However, the reported predictors might be insufficient for patients with early AIS. The aim was to investigate whether the initial vertebra-disc ratio (VDR) could serve as an effective predictor for curve progression in early thoracic AIS (premenarchal and Risser 0) undergoing brace treatment. PATIENTS AND METHODS: This study reviewed a consecutive series of early thoracic AIS girls with thoracic curve. All patients had accepted brace treatment and had regular follow-up. According to the bracing outcomes, patients were divided into two groups: Group P (progressed, curve progressed over six degrees or indicated for surgery) and Group NP (non-progressed). RESULTS: Totally 203 girls were included. There were 73 and 130 patients in Groups P and NP, respectively. The patients in Group P had greater initial VDR (1.9 ± 0.5 vs. 0.8 ± 0.4, P < 0.01) than Group NP. During the follow-up, it showed continuous higher values in Group P than Group NP. The logistic regression analysis revealed that initial VDR had an effective value for predicting curve progression in the braced early AIS girls. The ideal cut-off point of initial VDR was 1.5 for the prediction of curve progression. CONCLUSION: The initial VDR could serve as an effective predictor for curve progression in braced early AIS girls. Evaluation of this new parameter should be carefully performed at the bracing initiation.

Coronal Decompensation After Posterior-only Thoracolumbar Hemivertebra Resection and Short Fusion in Young Children With Congenital Scoliosis.

STUDY DESIGN: A retrospective study. OBJECTIVE: To determine the incidence and risk factors of coronal decompensation after posterior-only thoracolumbar hemivertebra (HV) resection and short fusion in patients younger than 5-years old. SUMMARY OF BACKGROUND DATA: Postoperative coronal decompensation may occur in operated patients during the follow up. However, there is a paucity of valid data regarding this complication in very young patients with thoracolumbar HV. METHODS: This study reviewed a consecutive series of patients (younger than 5 years) who had undergone posterior-only hemivertebrectomy and short fusion from January 2006 to December 2014. They had a minimum follow-up of 24 months. According to the coronal compensation behavior, they were divided into two groups: Group P (progressed, curve decompensated beyond twenty degrees) and Group NP (nonprogressed, curve well compensated). RESULTS: There were 179 patients included in this study. Mean age at surgery was 38 ±â€Š11 months. Mean follow-up was 41 ±â€Š11 months. Postoperative coronal decompensation was identified in 18 patients (rate, 10.1%) who constituted Group P. The remaining 161 patients had a well-compensated pattern. In contrast to Group NP, the patients in Group P had greater preoperative lowest instrumented vertebra (LIV) translation (18.5 mm ±â€Š6.4 mm vs. 10.5 mm ±â€Š4.9 mm, P < 0.01), and higher postoperative LIV disc angle (7.0°â€Š±â€Š3.1° vs. 3.1°â€Š±â€Š3.3°, P < 0.01) after surgery. During the follow up, LIV translation and LIV disc experienced continuous aggravation until initiation of bracing. Preoperative LIV translation (≥15.1 mm) and postoperative LIV disc angle (≥5.5°) were identified as two independent risk factors of coronal decompensation after surgery. CONCLUSION: After thoracolumbar hemivertebrectomy in children younger than 5 years, the overall rate of coronal decompensation is approximately 10.1%. As two independent risk factors of postoperative coronal decompensation, preoperative LIV translation (≥15.1 mm) and postoperative LIV disc angle (≥5.5°) should on all accounts be the major causes for concern. LEVEL OF EVIDENCE: 4.