Bone Mineral Density After Spinal Fusion Surgery for Adolescent Idiopathic Scoliosis at a Minimum 20-Year Follow-up

MRI-based vertebral bone quality score as a novel bone status marker of patients with adolescent idiopathic scoliosis

To investigate the application of MRI-based vertebral bone quality (VBQ) score in assessing bone mineral density (BMD) for patients with adolescent idiopathic scoliosis (AIS). We reviewed the data of AIS patients between January 2021 and October 2023 with MRI, whole-spine plain radiographs, quantitative computed tomography (QCT) and general information. VBQ score was calculated using T1-weighted MRI. Univariate analysis was applied to present the differences between variables of patients with normal BMD group (QCT Z-score > - 2.0) and low BMD group (QCT Z-score ≤ - 2.0). The correlation between VBQ score and QCT Z-score was analyzed with Pearson correlation test. A multivariate logistic regression model was used to determine the independent factors related to low BMD. Receiver operating characteristic curve (ROC) was drawn to analyze the diagnostic performance of VBQ score in distinguishing low BMD. A total of 136 AIS patients (mean age was 14.84 ± 2.10 years) were included, of which 41 had low BMD. The low BMD group had a significantly higher VBQ score than that in normal group (3.48 ± 0.85 vs. 2.62 ± 0.62, P < 0.001). The VBQ score was significantly negative correlated with QCT Z score (r =  - 0.454, P < 0.001). On multivariate analysis, VBQ score was independently associated with low BMD (OR: 4.134, 95% CI 2.136-8.000, P < 0.001). The area under the ROC curve indicated that the diagnostic accuracy of the VBQ score for predicting low BMD was 81%. A sensitivity of 65.9% with a specificity of 88.4% could be achieved for distinguishing low BMD by setting the VBQ score cutoff as 3.18. The novel VBQ score was a promising tool in distinguishing low BMD in patients with AIS and could be useful as opportunistic assessment for screening and complementary evaluation to QCT before surgery.

Long-term changes in bone mineral density following adolescent idiopathic scoliosis surgery: a minimum 34-year follow-up

PURPOSE

To investigate longitudinal changes in bone mineral density (BMD) in middle-aged female patients who underwent spinal fusion for adolescent idiopathic scoliosis (AIS).

METHODS

The study subjects were 229 female patients who were diagnosed with AIS and underwent spinal fusion between 1968 and 1988. A two-step survey study was conducted on 19 female AIS patients. BMD, Z-scores, T-scores, and the prevalence of osteoporosis and osteopenia were compared between the initial (2014-2016) and second (2022) surveys. Correlations between the annual changes in Z-scores and T-scores with radiographic parameters, body mass index (BMI), and the number of remaining mobile discs were analyzed.

RESULTS

BMD decreased significantly from the initial (0.802 ± 0.120 g/cm2) to the second survey (0.631 ± 0.101 g/cm2; p < 0.001). Z-scores decreased from 0.12 ± 1.09 to - 0.14 ± 1.04, while T-scores decreased significantly from - 0.70 ± 1.07 to - 1.77 ± 1.11 (p < 0.001). The prevalence of osteopenia and osteoporosis increased significantly from 36.8% to 89.5% (p = 0.002), but the increase in osteoporosis alone was not statistically significant (5.3% to 26.3%; p = 0.180). Moderate negative correlations were found between annual changes in Z-scores and both main thoracic (MT) curve (r = - 0.539; p = 0.017) and lumbar curve (r = - 0.410; p = 0.081). The annual change in T-scores showed a moderate negative correlation with the MT curve (r = - 0.411; p = 0.081).

CONCLUSION

Significant reductions in BMD and an increased prevalence of osteopenia and osteoporosis were observed in middle-aged female AIS patients who had undergone spinal fusion. The decline in Z-scores in patients with AIS suggested that there was an accelerated loss of BMD compared with the general population. Larger residual curves could pose an added osteoporosis risk. Further research is needed to understand if the onset of osteoporosis in AIS patients is attributable to the condition itself or the surgical intervention.

Outcome of bracing vs. surgical treatment in adolescents with idiopathic scoliosis based on device measured daily physical activity: a prospective pilot study

Adolescent idiopathic scoliosis (AIS) can be treated with bracing or surgery, which may affect patient's physical activity (PA). However, there are limited objective assessments of PA in patients with AIS. This study aims to compare the outcome of spinal bracing vs. surgery in patients with AIS based on a device that measured daily PA. In total 24 patients with AIS participated, including 12 patients treated with bracing and 12 with spinal surgery. Daily PA was measured throughout 4 consecutive days using four tri-axial accelerometers and patient-reported functional status was reported using the SRS-22 questionnaire. The participants were assessed both before the treatment and after treatment at a 12-month follow-up. Patients with AIS had no significant change in their PA levels at the 12-month follow-up after surgical correction. On the contrary, patients with AIS following a year-long bracing treatment had significantly reduced time spent active ( P  = 0.04) with an average reduction in walking steps by 2137 steps/day ( P  = 0.005). There was no significant difference in function, pain, self-image and mental health domains following both treatments, as reported by the SRS-22. There was a significant improvement in satisfaction for both treatment groups ( P  ≤ 0.02). Significantly reduced PA and increased sedentary time are reported in patients with AIS following bracing treatment. An objective PA assessment is recommended to track the effect of scoliosis treatment on PA. Patients with AIS should be actively encouraged to achieve and maintain their recommended daily PA levels irrespective of the type of treatment. Level of evidence: Level II.

Persistent low bone mineral density in adolescent idiopathic scoliosis: A longitudinal study

BACKGROUND

Since osteopenia has been reported to potentially associated with the progression of scoliosis, bone mineral density (BMD) might have some influences on adolescent idiopathic scoliosis (AIS). However, little is known about longitudinal BMD changes in AIS patients. This study aimed to investigate whether osteopenia in preoperative AIS patients persist at bone maturity, and to evaluate the association between BMD and AIS severity.

METHODS

We reviewed 61 AIS patients who underwent surgery when they were Risser grade 4 or below and less than 20 years old (16.6 ± 1.9 years), were followed until they were at least 18 years old and had a Risser grade of 5, and followed at least 2 years after the surgery (mean follow-up 4.9 ± 1.7 years). We evaluated radiographical parameters and proximal femur BMD before surgery and at the final follow-up. A BMD of less than the mean minus 1SD was considered as low BMD. Based on preoperative BMD, 37 patients were assigned to normal BMD (N) group (1.02 ± 0.08 g/cm2) and 24 patients to low BMD (L) group (0.82 ± 0.06 g/cm2).

RESULTS

All patients in the N-group had normal BMD at the final follow-up. In the L group, 15 patients (62.5%) had low BMD at the final follow-up (L-L group; preoperative 0.79 ± 0.05 g/cm2 and final follow-up 0.78 ± 0.05 g/cm2). The mean preoperative Cobb angle was significantly larger in the L-L group (67.8 ± 11.2°) than in those with normal BMD at the final follow-up (L-N group, 55.6 ± 11.8°) or the N-N group (50.8 ± 7.6°). Preoperative BMD was significantly negative correlated with the preoperative Cobb angle. The age at surgery and mean preoperative BMI were similar in the L-N and L-L groups.

CONCLUSIONS

Of AIS patients with low preoperative BMD, 62.5% still had low BMD after reaching bone maturity, and low BMD was associated with the severity of scoliosis.

Phosphorylated heat shock protein 27 improves the bone formation ability of osteoblasts and bone marrow stem cells from patients with adolescent idiopathic scoliosis

Background

Adolescent idiopathic scoliosis (AIS) is a scoliotic deformity of unknown etiology that occurs during adolescent development. Abnormal bone metabolism is closely related to AIS, but the cause is uncertain. Recent studies have shown that heat shock protein 27 (HSP27) and its phosphorylation (pHSP27) play important roles in bone metabolism. However, whether HSP27 and pHSP27 are involved in abnormal bone metabolism in AIS is unclear.

Methods

Osteoblasts (OBs) and bone marrow stem cells (BMSCs) were extracted from the facet joints and bone marrow of AIS patients and controls who underwent posterior spinal fusion surgery. The expression levels of HSP27 and pHSP27, as well as the expression levels of bone formation markers in OBs from AIS patients and controls, were examined by quantitative real-time PCR (qRT-PCR) and Western blotting. The mineralization ability of OBs from AIS patients and controls was analyzed by alizarin red staining after osteogenic differentiation. Heat shock and thiolutin were used to increase the levels of pHSP27 in OBs, and the levels of bone formation markers were also investigated. In addition, the levels of pHSP27 and the bone formation ability of BMSCs from AIS patients and controls were investigated after heat shock treatment.

Results

Lower pHSP27 levels and impaired osteogenic differentiation abilities were observed in the OBs of AIS patients than in those of controls. Thiolutin increased HSP27 phosphorylation and increased the mRNA levels of SPP1 and ALPL in OBs from AIS patients. Heat shock treatment increased SPP1 and HSP27 mRNA expression, pHSP27 levels, OCN expression, and mineralization ability of both OBs and BMSCs from AIS patients.

Conclusion

Heat shock treatment and thiolutin can increase the levels of pHSP27 and further promote the bone formation of OBs and BMSCs from AIS patients. Therefore, decreased pHSP27 levels may be associated with abnormal bone metabolism in AIS patients.

The experience of living with adolescent idiopathic scoliosis: a qualitative evidence synthesis using meta-ethnography

BACKGROUND

Adolescent idiopathic scoliosis (AIS) is a common spinal deformity with physical and psychosocial implications for adolescents. The aim of this qualitative evidence synthesis (QES) was to systematically search for, identify, and synthesise qualitative research in order to improve our understanding of what it is like to live with AIS and to facilitate empathetic and effective healthcare.

METHODS

We systematically searched 4 databases (Medline, EMBASE, PsycINFO and CINAHL) and used the 7 phases of meta-ethnography to synthesise qualitative evidence including studies with children and adolescents, and additional viewpoints from parents about the experience of AIS.

RESULTS

We distilled 7 themes. (1) Diagnosis turned time on its head revolves around the AIS diagnosis and the uncertainty of the future that accompanied it. (2) Usual activities no longer the same explores how activities and participation in everyday life are impacted by AIS. (3) Hiding my body describes the pervasive struggle with self-image and appearance. (4) I want to feel normal again explores adolescents' desire to return to 'normality' and challenges of feeling different. (5) Balancing isolation and support considers the relationships in the adolescents' lives alongside their feelings of isolation. (6) Trying to keep control of treatment decisions explores how adolescents and their parents strive to feel in control. (7) Fearing surgery yet feeling hopeful focused on the apprehension and fear around spinal surgery and the beacon of hope it represented.

CONCLUSIONS

Our QES contributes to the understanding of the adolescent experience of living with AIS. From our findings, clinicians can better understand the physical and psychosocial obstacles and the challenges faced throughout the journey of AIS to inform their clinical interactions with these patients.

Scoliosis Treatment With Growth-Friendly Spinal Implants (GFSI) Relates to Low Bone Mineral Mass in Children With Spinal Muscular Atrophy

BACKGROUND

Children with spinal muscular atrophy (SMA) frequently develop neuromuscular scoliosis at an early age, requiring surgical treatment with growth-friendly spinal implants (GFSI), such as magnetically controlled growing rods. This study investigated the effect of GFSI on the volumetric bone mineral density (vBMD) of the spine in SMA children.

METHODS

Seventeen children (age 13.2±1.2 y) with SMA and GFSI-treated spinal deformity were compared with 25 scoliotic SMA children (age 12.9±1.7 y) without prior surgical treatment as well as age-matched healthy controls (n=29; age 13.3±2.0). Clinical, radiologic, and demographic data were analyzed. For the calculation of the vBMD Z-scores of the thoracic and lumbar vertebrae, phantom precalibrated spinal computed tomography scans were analyzed using quantitative computed tomography (QCT).

RESULTS

Average vBMD was lower in SMA patients with GFSI (82.1±8.4 mg/cm3) compared with those without prior treatment (108.0±6.8 mg/cm3). The difference was more prominent in and around the thoracolumbar region. The vBMD of all SMA patients was significantly lower in comparison with healthy controls, especially in SMA patients with previous fragility fractures.

CONCLUSIONS

The results of this study support the hypothesis of reduced vertebral bone mineral mass in SMA children with scoliosis at the end of GFSI treatment in comparison with SMA patients undergoing primary spinal fusion. Improving vBMD through pharmaceutical therapy in SMA patients could have a beneficial effect on the surgical outcome of scoliosis correction while reducing complications.

LEVEL OF EVIDENCE

Therapeutic Level III.

More Prevalent and Severe Low Bone-Mineral Density in Boys with Severe Adolescent Idiopathic Scoliosis Than Girls: A Retrospective Study of 798 Surgical Patients

INTRODUCTION

A total of 0.1-0.8% of AIS patients progress to severe stages without clear mechanisms, and AIS girls are more prone to curve progression than boys. Recent studies suggest that AIS girls have systemic and persistent low bone-mineral density (BMD), which has been shown to be a significant prognostic factor of curve progression in AIS. The present study aimed to (a) investigate the prevalence of low BMD in patients with severe AIS and (b) assess the sexual dimorphism and independent risk factors of low BMD in severe AIS patients.

MATERIALS AND METHODS

A total of 798 patients (140 boys vs. 658 girls) with AIS who reached surgical threshold (Cobb ≥ 40°) were recruited. BMD were assessed using BMD Z-scores from dual-energy X-ray absorptiometry (DXA). Demographic, clinical, and laboratory values of the subjects were collected from their medical records. Logistic regression analysis was performed to identify independent risk factors of low BMD.

RESULTS

The overall prevalence of BMD Z-score ≤ -2 and ≤ -1 were 8.1% and 37.5%, respectively. AIS boys had significantly lower BMD Z-scores (-1.2 ± 0.96 vs. -0.57 ± 0.92) and higher prevalence of low BMD (Z-score ≤ -2: 22.1% vs. 5.2%, p < 0.001; Z-score ≤ -1: 59.3% vs. 32.8%, p < 0.001) than girls. Sex, BMI, serum alkaline phosphatase, and potassium were independent factors of low BMD in the severe AIS patients.

CONCLUSIONS

The present large cohort of surgical AIS patients revealed that low BMD is more prevalent and severe in boys than in girls with severe curves. Low BMD may serve as a more valuable predictive factor for curve progression to the surgical threshold in boys than girls with AIS.

Health-related quality of life (HRQOL) of adolescent idiopathic scoliosis (AIS) patients from surgery to after 30 years using SRS-22 questionnaire

STUDY DESIGN

A retrospective longitudinal follow-up study.

OBJECTIVES

The aim of this study is to evaluate the health-related quality of life (HRQOL) of post-operative AIS patients from less than 1 year to over 30 years using SRS-22 questionnaire. Some of our AIS patients who operated since the establishment of the scoliosis clinic have passed the 30th year. The HRQOL of patients many years after surgery had yet to be summarized and reported.

METHODS

SRS-22 questionnaire was conducted by 254 operated patients between the year 2016 and 2018. All post-operative patients who visited a specialized clinic for annual check-up within the study period completed SRS-22. The number of years since surgery per questionnaire was grouped per 1 year until the 10th year, and per 5 years afterwards. The 6 SRS-22 domain scores (function, pain, self-image, mental, satisfaction, mean) were compared across time period.

RESULTS

All SRS-22 domain scores in post-operative patients, except "Self-image", were relatively stable in the first 5 years until a steady drop starting from the 10th year. "Self-image" was statistically lower than "Function" and "Pain" from the 10th years to more than 30 years.

CONCLUSIONS

HRQOL of post-operative AIS patients remained stable until 10 years after surgery and was steadily decreasing. "Self-image" was consistently and statistically lower than the other scores. Patients who have surgically treated for more than 25 years are now at their perimenopause. Specific medical and psychosocial cares for this kind of patients are recommended to provide during the routine medical check-up.

LEVEL OF EVIDENCE

II.

Quantification evaluation of structural autograft versus morcellized fragments autograft in patients who underwent single-level lumbar laminectomy

Posterolateral fusion (PLIF) with autogenous bone graft is considered the gold standard for lumbar spinal fusion. However, the fusion rate and effectiveness of locally derived corticocancellous structural autograft vs. morcellized fragments autograft for lumbar PLIF, following single level lumbar laminectomy in patients with symptomatic lumbar spinal stenosis, remain unknown. Thus, the present study aimed to compare the fusion rates of corticocancellous structural autograft and morcellized fragments autograft for the treatment of lumbar PLIF. A randomized self-controlled trial was conducted comprising of 135 patients with symptomatic lumbar spinal stenosis, single level lumbar laminectomy and PLIF, with corticocancellous structural autograft (group 1) and morcellized fragments autograft (group 2). The primary outcome measurements included the PLIF rate, radio density and dimensions of PLIF mass on both sides, which were assessed via X-rays at 3, 6 and 12 months, postoperatively. Furthermore, changes in bilateral bone fusion bridges were assessed via CT scanning, according to the Lenke CT fusion measurement criteria. The follow-up period lasted for 1 year (period between January 2013 and January 2018). Of the 135 patients were initially included in the present study, 7 patients were lost during the following up process. Therefore, data from 128 patents were eventually assessed, 94.8% of surgical levels were observed at Honghui Hospital. According to the Lenke CT fusion measurement criteria, the overall unilateral fusion rates were 71.9% (92/128) in group 1 and 31.3% (40/128) in group 2. Furthermore, both the radio density and dimensions of PLIF mass significantly decreased at a faster rate in group 1 compared with group 2 (radio density; 0.65-0.49 vs. 0.63-0.61; P<0.05 and PLIF mass; 398-124 vs. 376-223 mm²; P<0.05). The CT scan results demonstrated that the mean volume of bone graft was significantly greater in group 1 compared with group 2, at 12 months postoperatively (1.47 vs. 1 cm³; P<0.05). Taken together, the results of the present study suggested that corticocancellous structural autograft is more effective for earlier resorption and stabilization of patients undergoing PLIF, compared with morcellized fragments autograft.

Patients majoring in a healthcare field after scoliosis surgery: Comparison with the national census in Japan

BACKGROUND

Although scoliosis surgery early in life may affect the career choice of the patient in favor of a healthcare field, no study has analyzed this relationship. We investigated the career paths of patients after scoliosis surgery.

METHODS

A total of 212 patients with scoliosis who underwent corrective surgery at 12-17 years of age were mailed a questionnaire, of whom 98 (mean age at survey: 21.0 ± 1.7, years) responded. Choice of study major was determined by the same questions used in the Japanese national census.

RESULTS

Of the 98 patients, 35% chose a career in healthcare compared with 11% of the general population of the same age, based on the national census. Healthcare was the most popular career choice of patients, whereas it ranked fourth according to the national census. Furthermore, 87% of patients reported that their decision to pursue a healthcare-related career was affected by their own medical experiences. Among the healthcare-related occupations, nursing ranked first, accounting for 35% of all healthcare professions chosen by the patients. Compared with patients who chose a non-healthcare career, those choosing a healthcare career decided on their study major at a significantly lower age.

CONCLUSIONS

One-third of patients with scoliosis who underwent spine surgery chose a career in a healthcare field. Furthermore, an earlier age at the time of making a career decision was a significant factor associated with choosing a healthcare career. These findings suggest that the patients' experiences in the hospital positively affected their future career paths.

Prospective 10-year follow-up assessment of spinal fusions for thoracic AIS: radiographic and clinical outcomes

STUDY DESIGN

Prospective registry. The evolution of spinal instrumentation has provided better outcomes in adolescent idiopathic scoliosis (AIS); however, there is a paucity of reliable prospective information on 10-year post-operative outcomes of modern surgical techniques.

METHODS

A prospective multicenter registry of patients who had surgical correction of AIS was reviewed. Patients with major thoracic scoliosis (Lenke types 1-4) operated on between 1997 and 2007, with 10-year post-operative follow-up data were included. Radiographic and clinical outcomes including Scoliosis Research Society (SRS)-22 scores and revision surgeries were evaluated.

RESULTS

One hundred and seventy-four patients (mean 25.0 years of age at most recent evaluation) were included. Pedicle screw constructs were used in 102 patients (58%), hook or hybrid constructs in 22 (13%), and anterior screw-rod constructs in 50 (29%). The mean pre-operative thoracic Cobb angle was corrected from 53° to 18° initially. At 10-year follow-up, the mean thoracic curve was 22° (mean 57% correction), with 29 patients (16.7%) having loss of correction (LOC) ≥ 10°. There were a total of 14 revision surgeries performed in 13 patients (7.5%). SRS-22 pain (p = 0.035), self-image (p < 0.001), and total scores (p < 0.001) significantly improved at 2-year follow-up. The mean pain score at 10-year follow-up was similar to pre-operative scores and lower (more pain) than previously published mean scores of normal adults aged 20-40 years (p < 0.05).

CONCLUSIONS

Spinal fusion patients report SRS-22 quality of life 10 years after scoliosis surgery that is minimally reduced compared to healthy peers and substantially better than an un-operated cohort of comparably aged scoliosis patients. Adolescents with thoracic idiopathic scoliosis should expect little if any change in their health-related quality of life compared to before surgery, high satisfaction, and a 7.5% chance of revision surgery 10 years after their index spinal fusion.

LEVEL OF EVIDENCE

Therapeutic II.

Can posterior implant removal prevent device-related vertebral osteopenia after posterior fusion in adolescent idiopathic scoliosis? A mean 29-year follow-up study

PURPOSE

To determine whether posterior implant removal prevents stress-shielding-induced vertebral osteopenia within the posterior fusion area in surgically treated patients with adolescent idiopathic scoliosis (AIS).

METHODS

Eighteen patients with major thoracic AIS (mean age, 43.3 years; range, 32-56 years; mean follow-up, 28.8 years, range, 20-39 years) who underwent posterior spinal fusion (PSF) alone between 1973 and 1994 were included. Participants were divided into implant removal (group R, n = 10, mean interval until implant removal, 50 months) and implant non-removal groups (group NR, n = 8). Bone mineral density was evaluated using the Hounsfield units (HU) of the computed tomography image of the full spine. The HU values of the UIV-1 (one level below the uppermost instrumented vertebra), apex, LIV+1 (one level above the lowermost instrumented vertebra), and LIV-1 (one level below the lowermost instrumented vertebra; as a standard value) were obtained. Stress-shielding-induced osteopenia was assessed as the UIV-1/LIV-1, apex/LIV-1, and LIV+1/LIV-1 HU ratios (× 100).

RESULTS

Overall (median, 25th-75th percentile), the apex (144.7, 108.6-176.0) and LIV+1 (159.4, 129.7-172.3) demonstrated lower HU values than LIV-1 (180.3, 149.2-200.2) (both comparisons, p < .05). Comparison of groups R and NR showed no significant differences in the scoliosis correction rate, bone mineral density of the proximal femur, the HU absolute values of all investigated vertebrae, or in the HU ratios of the investigated vertebrae to LIV-1.

CONCLUSION

Instrumented PSF causes stress-shielding-induced osteopenia of the vertebral body within the fusion area in adulthood, which cannot be prevented by posterior implant removal, probably due to firm fusion mass formation. These slides can be retrieved under Electronic Supplementary Material.