Hongda Bao

Unanticipated revision surgery in adult spinal deformity: an experience with 815 cases at one institution.

Study Design. Retrospective case series. Objective. This study reviewed the overall prevalence and indications of revision surgical procedures for adult scoliosis in a single institution. In this largest single-institution series, revision surgery in adult scoliosis was required for a relatively low proportion of cases (7.61%). The main indications were implant breakage, deformity progression, and infection. Summary of Background Data. Spine fusion is considered as the final therapeutic intervention in the management of adult scoliosis. However, reports on the repeat surgical intervention of adult scoliosis predate the use of advanced instrumentation systems. Methods. The scoliosis database of our center was searched, and all cases with index spinal fusion surgical procedures performed for adult scoliosis from 1998 to 2011 with the follow-up period of more than 2 years were identified. The clinical data and radiographs of patients were reviewed to provide information on the indication of initial operation and any subsequent revision surgery. A total of 815 patients were identified, with a mean age of 30.49 years (range, 20–76 yr). The mean follow-up periods were 6.4 years (range, 2–15 yr) for the entire cohort and 7.6 years (range, 2.5–12 yr) for the subset of the cohort requiring revision. Results. The patients exhibiting multiple reasons for revision were classified under primary reason and subjected to subsequent analysis. Among the 815 patients, 62 (7.61%) underwent at least 1 revision surgery. The most common reasons for revision were implant breakage (23/62; 37.1%), deformity progression (10/62; 16.1%), and infection (9/62; 14.5%). The other indications were pseudarthrosis (n = 8), implant dislodgement (n = 6), junctional kyphosis (n = 5), and neurological deficit (n = 1). Revision rate was significantly higher in patients older than 40 years (15.23% vs. 5.87%), in patients with degenerative or congenital scoliosis (15.12% vs. 12.82%), or in patients with hybrid constructs (12.12% vs. 5.82%). Conclusion. In this largest single-institution series, revision surgery after index spinal fusion in patients with adult scoliosis was required for a relatively low proportion of surgical cases (7.61%). The main indications for revision were implant breakage, deformity progression, and infection. Level of Evidence: 3

Will immediate postoperative imbalance improve in patients with thoracolumbar/lumbar degenerative kyphoscoliosis? A comparison between Smith-Petersen osteotomy and pedicle subtraction osteotomy with an average 4 years of follow-up.

Study Design. A retrospective radiographical study. Objective. To compare compensatory behavior of coronal and sagittal alignment after pedicle subtraction osteotomy (PSO) and Smith-Petersen osteotomy (SPO) for degenerative kyphoscoliosis. Summary of Background Data. There was a paucity of literature paying attention to the postoperative imbalance after PSO or SPO and natural evolution of the imbalance. Methods. A retrospective study was performed on 68 consecutive patients with degenerative kyphoscoliosis treated by lumbar PSO (25 patients) or SPO (43 patients) procedures at a single institution. Long-cassette standing radiographs were taken preoperatively, postoperatively, and at the last follow-up and radiographical parameters were measured. The lower instrumented vertebral level and level of osteotomy were compared between the patients with and without improvement. Results. Negative sagittal vertical axis (SVA) was observed in the PSO group postoperatively, implying an overcorrection of SVA. This negative SVA improved spontaneously during follow-up (P < 0.05). Coronal balance was found to worsen immediately postoperatively in the SPO group (P < 0.05). At the last follow-up, spontaneous improvement was observed in 15 patients and the average coronal balance decreased to 16.35 mm. For the 15 patients with improved coronal balance, fusion at L5 or above was more common compared with the 11 patients with persisted postoperative imbalance (P = 0.027), whereas no difference in term of levels of osteotomy was found (P > 0.05). Conclusion. The overcorrection of SVA is more often seen in the PSO group. The coronal imbalance is more likely to occur in the SPO group. The postoperative sagittal imbalance often spontaneously improves with time. Lower instrumented vertebra at S1 or with pelvic fixation should be regarded as potential risk factors for persistent coronal imbalance in patients with SPO. Level of Evidence: 3

Analysis of L5 incidence in normal population use of L5 incidence as a guide in reconstruction of lumbosacral alignment.

Study Design. Cross-sectional study. Objective. To establish a statistic model defining the relationship between L5 incidence (L5I) and pelvic incidence (PI) in normal population and to illustrate the importance of L5I in maintaining the normal sagittal profile of spine. Summary of Background Data. L5I was proposed for the evaluation of postoperative improvements in high-grade isthmic spondylolisthesis. It has been proven that a postoperative improvement in L5I was correlated with a better surgical outcome, indicating that the restoration of L5I is important in restoring normal sagittal balance and spinal morphology. Methods. This retrospective study recruited 138 healthy volunteers, who were stratified into 2 groups according to age: adolescent group (13–18 yr) and adult group (19–35 yr). Parameters including PI, pelvic tilt, sacral slope, lumbar lordosis (LL), upper arc of the LL, lower arc of the LL, L5I, lumbosacral angle, and height of L5–S1 disc were measured on the long-cassette standing upright lateral radiographs of the spine and pelvis. The relations between all parameters were determined via the Pearson correlation coefficient (r). Linear regression was applied to model the relationship between PI and L5I. Results. This study demonstrated significant correlation between L5I and PI with a coefficient of 0.818, and a formula based on linear regression was established to estimate the ideal L5I from PI as follows: L5I = 0.725 PI − 12.757. Pelvic tilt, sacral slope, lumbosacral angle, LL, lower arc of the LL, and height of L5–S1 disc were also found strongly correlated with L5I, whereas no correlation was found between upper arc of the LL and L5I. Conclusion. Strong correlations were found between L5I and spinopelvic parameters in healthy subjects, indicating that L5I was an important parameter in local lumbosacral alignment. Ideal postoperative L5I could be mathematically calculated by PI according to the formula as follows: L5I = 0.725 PI − 12.757, suggesting that calculated ideal L5I could be regarded as a guide in surgical decision making. Level of Evidence: 3

Coronal curvature and spinal imbalance in degenerative lumbar scoliosis: disc degeneration is associated.

Study Design. A retrospective radiographical study. Objective. To determine the association between disc degeneration and spinal malalignment on both coronal and sagittal planes in patients with degenerative lumbar scoliosis (DLS). Summary of Background Data. In recent years, a thorough understanding of spinal coronal balance and sagittal alignment has become more and more important in treating patients with DLS. Although degeneration of discs has been generally accepted as the main cause of DLS, to date no study has documented the relationships between disc degeneration and the curve magnitude as well as spinal imbalance. Methods. In this study, 57 patients with DLS were recruited. Degeneration of the apical disc, lower end vertebral (EV) discs and regional lumbar discs (L1–L2 and L5–S1) were quantitatively evaluated by the Pfirrmann score based on T2-weighted magnetic resonance images. Radiographical parameters including Cobb angle, coronal trunk shift, sagittal vertical axis (SVA), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence, pelvic tilt, and sacral slope were measured from long-cassette standing upright radiographs. Subjects were assigned to 4 groups: both coronal and sagittal balanced (C+ S+); coronal imbalanced but sagittal balanced (C− S+); coronal balanced but sagittal imbalanced (C+ S−); and both coronal and sagittal imbalanced (C− S−). The Spearman correlation was used to identify the relationship between the Pfirrmann score of disc degeneration and radiographical parameters. Analysis of variance 2×2 factorial design was performed to identify the decisive factors affecting coronal and sagittal balance. Results. On the basis of the criteria for each group, 19 patients were assigned to group A (C+ S+), 10 patients to group B (C− S+), 11 patients to group C (C+ S−), and 17 patients to group D (C− S−). The Pfirrmann score of regional lumbar disc degeneration strongly correlated with Cobb angle, SVA, TK, and LL (r = −0.364, −0.386, 0.283, and 0.479, respectively, P < 0.01). Specifically, the Pfirrmann score of apical disc degeneration correlated with Cobb angle, whereas degeneration of lower EV discs correlated with SVA, TK, and LL. On the basis of analysis of variance 2 × 2 factorial design, the score of the lower EV disc degeneration significantly correlated with sagittal balance (P < 0.05). Conclusion. This study demonstrated that the lower EV disc degeneration strongly correlated with sagittal imbalance in patients with DLS, implying that disc degeneration may be regarded as a potential risk factor for sagittal imbalance. This result strengthened the importance of not selecting the lower EV as the lower instrumented vertebra during the surgical decision making, which may lead to deterioration of sagittal balance. Disc degeneration was also strongly correlated with sagittal malalignment, as demonstrated by a more positive SVA, decreased TK and LL, providing insight into reasons for low quality of life in elderly patients with DLS. Level of Evidence: 3

Is the sacro-femoral-pubic angle predictive for pelvic tilt in adolescent idiopathic scoliosis patients?

Study Design: This was a retrospective radiographic study. Objective: The aim of this study was to evaluate the correlation between pelvic tilt (PT) and the sacro-femoral-pubic angle (SFP angle) in AIS patients and to clarify whether the predictability of PT is affected by different curve patterns. Summary of Background Data: Pelvic retroversion is one of the compensatory mechanisms to maintain upright position and is also tied to health-related quality of life in patients with adolescent idiopathic scoliosis (AIS). However, measurement of spino-pelvic parameters including PT may not be accurate because of difficulty in visualizing femoral heads on lateral radiographs in some patients. Materials and Methods: In this study, 101 female AIS patients were recruited. The subjects were divided into 2 groups: thoracic scoliosis (TS) and lumbar scoliosis (LS) group. Long-cassette standing upright radiographs were obtained; PT and SFP angles were measured through digital analysis software (Surgimap Spine Software, New York, NY). The relations between PT and SFP angle were determined by the Pearson correlation coefficient (r). Linear regressions between PT and SFP angle were also performed. Results: The SFP angle was strongly correlated with PT in both groups, and PT could be estimated by the formulas: PT=74.052−0.991×SFP angle in the TS group and PT=65.345−0.881×SFP angle in the LS group. In the TS group, the SFP angle correlated with PT strongly with a Pearson coefficient of 0.65. Whereas in the LS group, the coefficient was weaker than that in the TS group (0.48 vs. 0.65); however, it still showed that PT was significantly associated with SFP. Conclusions: Given the high correlation between PT and SFP angle, the SFP angle should be considered a reliable alternative option to PT, which has routinely excellent visibility in coronal films in AIS patients. The predictability was more accurate for AIS patients with thoracic curves than with lumbar curves.

Mismatch Between Proximal Rod Contouring and Proximal Junctional Angle: A Predisposed Risk Factor for Proximal Junctional Kyphosis in Degenerative Scoliosis.

Study Design. A retrospective study. Objective. To investigate whether the mismatch between proximal junctional angle (PJA) and the proximal rod contouring contributed to the occurrence of postoperative proximal junctional kyphosis (PJK) in degenerative scoliosis. Summary of Background Data. PJK is one of the complications in the treatment of degenerative scoliosis, the postoperative PI-LL mismatch and the increased rod stiffness are supposed to be the etiology of PJK. However, the impact of rod contouring on PJK has not been fully illustrated. Methods. A retrospective study was performed on 27 consecutive degenerative scoliosis patients (three males and 24 females) who underwent corrective surgery with more than 2-year follow-up. Radiographic parameters included proximal rod contouring angle (PRCA) and PJA at the three time-points. The subjects were divided into two groups: PJK group and non-PJK group with the definition of PJK as a PJA more than 10°. The mismatch between PRCA and post-op PJA, defined as the difference between PRCA and postop PJA of more than 5°, was then compared with PJK and non-PJK group. Results. The patients’ mean age was 60.48 ± 6.47 years old with a mean Cobb angle of 40.89 ± 14.33°. Twelve patients, with a mean PJA of 18.67 ± 5.31° at the last followup, were stratified into the PJK group, while the remaining 15 patients, with a mean PJA of 5.33 ± 2.47, were placed into the non-PJK group. A significant difference in the mismatch between post-op PJA and PRCA was observed between PJK and non-PJK group (8.83 ± 5.07° vs. 4.07 ± 2.91°, P = 0.005). Meanwhile the difference of mismatch between preop PJA and PRCA showed no statistical significance (5.16 ± 4.24° vs. 3.00 ± 2.48°, P = 0.109). Conclusion. Mismatch between rod contouring and postoperative proximal spinal curve may be a predisposed risk factor for PJK in degenerative scoliosis. Level of Evidence: 4

Coronal imbalance in degenerative lumbar scoliosis: Prevalence and influence on surgical decision-making for spinal osteotomy

AIMS There is a paucity of information on the pre-operative coronal imbalance in patients with degenerative lumbar scoliosis (DLS) and its influence on surgical outcomes. PATIENTS AND METHODS A total of 284 DLS patients were recruited into this study, among whom 69 patients were treated surgically and the remaining 215 patients conservatively Patients were classified based on the coronal balance distance (CBD): Type A, CBD < 3 cm; Type B, CBD > 3 cm and C7 Plumb Line (C7PL) shifted to the concave side of the curve; Type C, CBD > 3 cm and C7PL shifted to the convex side. RESULTS A total of 99 of the 284 (34.8%) patient presented with a pre-operative coronal imbalance (mean CBD: 48.5, standard deviation 18.7 mm). More patients with a Type B malalignment were observed than with a Type C malalignment (62 versus 37). A total of 21 pf the 69 (30.4%) surgically treated patients had a post-operative coronal imbalance, which was found to be more prevalent in Type C patients (p < 0.001). At follow-up, less improvement was observed in terms of Short Form-36 Physical Component Score and visual analogue score for back pain (p = 0.034 and 0.025, respectively) in Type C patients. CONCLUSION This study shows that patients with Type C coronal malalignment may be at greater risk of post-operative coronal imbalance following posterior osteotomy. Cite this article: Bone Joint J 2016;98-B:1227-33.

Scoliosis Related Information on the Internet in China: Can Patients Benefit from This Information?

Background There has been an increasing popularity of searching health related information online in recent years. Despite that considerable amount of scoliosis patients have shown interest in obtaining scoliosis information through Internet, previous studies have demonstrated poor quality of online information. However, this conclusion may vary depending on region and culture. Since China has a restricted Internet access outside of its borders, the aim of this study is to evaluate the quality of scoliosis information available online using recognized scoring systems and to analyze the Internet as a source of health information in China. Methods A survey-based questionnaire was distributed to 280 respondents at outpatient clinics. Information on demographics and Internet use was collected. Binary logistic analysis was performed to identify possible predictors for the use of Internet. In addition, the top 60 scoliosis related websites assessed through 4 search engines were reviewed by a surgeon and the quality of online information was evaluated using DISCERN score and JAMA benchmark. Results Use of the Internet as a source for scoliosis related information was confirmed in 87.8% of the respondents. College education, Internet access at home and urban residence were identified as potential predictors for Internet use. However, the quality of online scoliosis related information was poor with an average DISCERN score of 27.9±11.7 and may be misleading for scoliosis patients. Conclusion The study outlines the profile of scoliosis patients who use the Internet as a source of health information. It was shown that 87.8% of the scoliosis patients in outpatient clinics have searched for scoliosis related information on Internet. Urban patients, higher education and Internet access at home were identified as potential predictors for Internet search. However, the overall quality of online scoliosis related information was poor and confusing. Physician based websites seemed to contain more reliable information.

Vertebral Rotatory Subluxation in Degenerative Scoliosis: Facet Joint Tropism Is Related

Study Design. A cross-sectional study. Objective. To identify facet tropism as one of the possible risk factors leading to vertebral rotatory subluxation (VRS). Summary of Background Data. VRS has been considered as one of the prognostic factors for degenerative scoliosis. Although several risk factors of VRS, including age and Cobb angle, have been investigated, few studies exist that have evaluated the correlation between VRS and anatomical structures of the vertebral column. Methods. This retrospective study recruited 23 patients diagnosed with degenerative lumbar scoliosis with VRS and 20 patients with degenerative scoliosis without VRS. The lateral translation on coronal radiographs was measured and 5 mm was used as the cutoff value to define rotatory subluxation. Computed tomographic scans for facet joints were made for all lumbar levels. The difference between right and left facet angles was recorded as &Dgr;FA. Facet tropism was defined as a difference between the bilateral facet angles of more than 10°. Results. In this study, VRS was most commonly found at the L3–L4 level (49%) and, with decreasing frequency at L2–L3 (24%), L4–L5 (20%), and L1–L2 (7%). On the convex side of the main curve, face joints at levels with VRS were more coronally oriented compared with those at levels without VRS (41.64°± 11.65° vs. 36.30°± 10.99°, P = 0.034). &Dgr;FA was also significantly different between levels with and without VRS (P = 0.005). A strong correlation was found between &Dgr;FA and lateral translation, with a coefficient of 0.33 (P < 0.001). In addition, &Dgr;FA and a larger Cobb angle were found to be significantly associated with VRS based on binary regression analysis, with an odds ratio of 4.68 and 2.14, respectively. Conclusion. Facet tropism was more significantly observed at levels with VRS. On the convex side of the main curve, facet joints at levels with VRS were more coronally oriented. A larger Cobb angle and severe facet tropism in degenerative scoliosis should be considered to be related to VRS.

Polymorphism of rs2767485 in Leptin Receptor Gene is Associated With the Occurrence of Adolescent Idiopathic Scoliosis.

Study Design. A genetic association study of leptin receptor (LEPR) gene with adolescent idiopathic scoliosis (AIS) in the Chinese Han population. Objective. To determine whether LEPR gene polymorphisms are associated with the predisposition and/or disease severity of AIS. Summary of Background Data. Patients with AIS were reported to have lower body mass index (BMI), abnormal leptin bioavailability, and systemic lower bone mass, which implied that leptin/LEPR signaling pathway may be implicated in the etiology of AIS. Previous association study of the polymorphisms in leptin gene did not show significant differences between AIS cases and controls. However, no study has been done to investigate the relationship between genetic polymorphisms of the LEPR gene and susceptibility to AIS. Methods. 570 patients with AIS aged 10 to 18 years were enrolled, and 570 age-matched healthy subjects were recruited as controls. 6 single nucleotide polymorphisms (SNPs) (rs1137101, rs1137100, rs4655555, rs2767485, rs1751492, and rs8179183) of LEPR gene were selected. The polymorphisms were genotyped using the polymerase chain reaction (PCR)-based Invader assay. Case–control study was performed to define the contribution of the 6 SNPs to predisposition of AIS. 1-way analysis of variance (ANOVA) test was used to compare the mean Cobb angles and BMI among patients with different genotypes in case-only analyses. Statistical significance was set at P < 0.05. Results. Both the genotype and allele frequencies of SNP rs2767485 were significantly different between the patient with AIS and the control groups. No significant difference of allele frequency was noted in other 5 SNPs between the patients with AIS and the normal controls. Both the mean maximum Cobb angles and BMI of different genotype AIS groups were similar to each other for all the 6 SNPs (P > 0.05). Conclusion. Polymorphism of rs2767485 in LEPR gene is associated with the occurrence of AIS, suggesting LEPR is a predisposition gene. Level of Evidence: 4