Predictive biomarkers of ossification progression and bone metabolism dynamics in patients with cervical ossification of the posterior longitudinal ligament.

PURPOSE: This study aimed to establish biomarkers to predict the progression of ossification by examining ossification volume and bone metabolism dynamics in patients with ossification of the posterior longitudinal ligament (OPLL). METHODS: We assessed OPLL progression using computed tomography-based three-dimensional (3D) image analysis and examined bone metabolism dynamics in 107 patients with OPLL (men, 72; women, 35; mean age, 63.6 years). The volume of OPLL was calculated twice during the follow-up period, and OPLL progression was evaluated by the annual rate of ossification increase. Bone metabolism dynamics were assessed by routine blood tests and analysis of various serum biomarkers (including 25-hydroxyvitamin D, intact parathyroid hormone, fibroblast growth factor 23, intact N-terminal propeptide of type 1, tartrate-resistant acid phosphatase isoform 5b, sclerostin, and Dickkopf-1) and bone mineral density (BMD). Patients were classified into the progression (P) or non-progression (NP) group according to the annual rate of increase in previous 3D image analyses, and associated factors between these groups were compared. RESULTS: The P and NP groups consisted of 29 patients (23 men and 6 women) and 78 patients (49 men and 29 women), respectively. Univariate analysis revealed significant differences in terms of age, body mass index, serum phosphorus, serum sclerostin, and BMD. In multivariate analysis, age, serum phosphorus, and serum sclerostin were identified as independent factors associated with OPLL progression. CONCLUSION: Younger age, hypophosphatemia, and high serum sclerostin are risk factors for OPLL progression. Serum phosphorus and sclerostin could serve as important biomarkers for predicting ossification progression.

Randomized trial of granulocyte colony-stimulating factor for spinal cord injury.

Attenuation of the secondary injury of spinal cord injury (SCI) can suppress the spread of spinal cord tissue damage, possibly resulting in spinal cord sparing that can improve functional prognoses. Granulocyte colony-stimulating factor (G-CSF) is a haematological cytokine commonly used to treat neutropenia. Previous reports have shown that G-CSF promotes functional recovery in rodent models of SCI. Based on preclinical results, we conducted early phase clinical trials, showing safety/feasibility and suggestive efficacy. These lines of evidence demonstrate that G-CSF might have therapeutic benefits for acute SCI in humans. To confirm this efficacy and to obtain strong evidence for pharmaceutical approval of G-CSF therapy for SCI, we conducted a phase 3 clinical trial designed as a prospective, randomized, double-blinded and placebo-controlled comparative trial. The current trial included cervical SCI [severity of American Spinal Injury Association (ASIA) Impairment Scale (AIS) B or C] within 48 h after injury. Patients are randomly assigned to G-CSF and placebo groups. The G-CSF group was administered 400 µg/m2/day × 5 days of G-CSF in normal saline via intravenous infusion for five consecutive days. The placebo group was similarly administered a placebo. Allocation was concealed between blinded evaluators of efficacy/safety and those for laboratory data, as G-CSF markedly increases white blood cell counts that can reveal patient treatment. Efficacy and safety were evaluated by blinded observer. Our primary end point was changes in ASIA motor scores from baseline to 3 months after drug administration. Each group includes 44 patients (88 total patients). Our protocol was approved by the Pharmaceuticals and Medical Device Agency in Japan and this trial is funded by the Center for Clinical Trials, Japan Medical Association. There was no significant difference in the primary end point between the G-CSF and the placebo control groups. In contrast, one of the secondary end points showed that the ASIA motor score 6 months (P = 0.062) and 1 year (P = 0.073) after drug administration tend to be higher in the G-CSF group compared with the placebo control group. Moreover, in patients aged over 65 years old, motor recovery 6 months after drug administration showed a strong trend towards a better recovery in the G-CSF treated group (P = 0.056) compared with the control group. The present trial failed to show a significant effect of G-CSF in primary end point although the subanalyses of the present trial suggested potential G-CSF benefits for specific population.

Flexibility of the thoracic curve and three-dimensional thoracic kyphosis can predict pulmonary function in nonoperatively treated adult patients with adolescent idiopathic scoliosis.

BACKGROUND: Although several radiographic predictors for pulmonary function in adolescent patients have been reported, those in adult patients remain unclear. Therefore, we aimed to investigate the associations between spinal deformity and pulmonary function in nonoperatively treated adult patients with adolescent idiopathic scoliosis (AIS). METHODS: Of 319 patients treated nonoperatively for AIS, 90 (average age, 40.0 ± 6.5 years) underwent both full-length standing radiographs and pulmonary function test. Standard two-dimensional (2-D) radiographic measurements were performed. Three-dimensional thoracic kyphosis (3-D TK) was calculated from 2-D standing radiograph data using a validated formula: 3-D TK (°) = 18.1 + 0.81 × (2-D TK) + 0.54 × (Cobb angle of thoracic curve). 3-D TK was defined as the sum of segmental kyphosis between T5 and T12, which eliminates the overestimation of TK in 2-D measurements due to rotational deformity. Bivariable correlation analysis, followed by a stepwise multiple linear regression analysis, was performed. RESULTS: The average Cobb angle of the thoracic curve at the time of survey was 49.4° ± 14.6° with flexibility of 37.5% ± 18.2%. Thoracic curve magnitude, flexibility, apical vertebral rotation and translation, and 3-D TK were significantly correlated with percent-predicted forced vital capacity (%FVC) and expiratory volume in 1 s (%FEV1.0). Stepwise multiple regression analysis showed that curve flexibility and 3-D TK were significant, independent predictors of %FVC (R2 = 0.358) and %FEV1.0 (R2 = 0.335), curve flexibility having a greater impact (standardized coefficient > 0.45) than 3-D TK (<0.32). CONCLUSIONS: Our results indicate that nonoperatively treated patients with AIS should be recommended to maintain flexibility of the thoracic curve to prevent future pulmonary impairment. Moreover, 3-D TK is another independent predictor of pulmonary function, which suggests that segmental sagittal alignment is a component of deformity correction to focus on.

Three-dimensional morphological analysis of cervical foraminal stenosis using dynamic flexion-extension computed tomography images.

BACKGROUND: Morphological features of foraminal stenosis in cervical spondylotic radiculopathy and the adequate extent of facet resection in posterior cervical foraminotomy remain uncertain. Herein, we evaluated quantitatively foraminal widths in cervical spondylotic radiculopathy on dynamic flexion-extension computed tomography using a novel three-dimensional analysis method and determined the extent of facet resection in posterior cervical foraminotomy. METHODS: Seventeen patients undergoing posterior cervical foraminotomy for cervical spondylotic radiculopathy were evaluated. A neuroforamen three-dimensional model was built from preoperative images of flexion-extension computed tomography myelography, and an ordinary cervical spine coordinate system and an original neuroforaminal coordinate system, were established. In the neuroforaminal coordinate system, minimum areas perpendicular to the long axis by the slices from inlet to outlet of neuroforamen and narrowest foraminal width in a slice of minimum area were measured. The location of the narrowest region from inlet of the foramen was calculated. Ratios of minimum and sufficient facet resection were obtained from the location of the narrowest region in the neuroforaminal coordinate system. RESULTS: The narrowest foraminal widths (flexion/extension) in the cervical spine coordinate system and the neuroforaminal coordinate system were 2.9/2.3 and 2.6/1.9 mm, respectively. The mean values of the location of the narrowest region (flexion/extension) were 0.27/0.22 and 0.50/0.45 mm, respectively, and the narrowest region in the neuroforaminal coordinate system was located on the outer side than in the cervical spine coordinate system (p < 0.001). The ratios of minimum and sufficient facet resection were 23 ± 8% and 32 ± 9%, respectively. CONCLUSIONS: The narrowest regions both in flexion and extension are located at the middle of the foramen based on the neuroforaminal coordinate system. Ordinary evaluation of axial computed tomography images likely underestimates the extent of facet resection, whereas certain extent of facet resection does not exceed 50% in cases with single-level cervical spondylotic radiculopathy. STUDY DESIGN: A retrospective case control study.

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.

Risk factors for surgical site infection following spinal instrumentation surgery.

BACKGROUND: In spinal instrumentation surgeries, surgical site infection (SSI) is one of the complications to be avoided. However, spinal instrumentation surgeries have a higher rate of SSI than other clean orthopedic surgeries. The purpose of this study was to investigate the risk factors for SSI following spinal instrumentation surgeries and contribute to the prevention of SSIs by identifying high-risk patients. METHODS: Records of 431 patients who underwent spinal instrumentation surgeries from 2011 to 2014 with a minimum follow-up period of 90 days were retrospectively reviewed. Associations of SSI with various preoperative, operative, and postoperative factors were statistically analyzed with univariate and stepwise multivariate logistic regression analysis. RESULTS: Deep or superficial SSIs were observed in 15 patients (3.5%). Univariate analysis revealed significant association of SSI with diabetes mellitus (odds ratio [OR] 4.7, 95% confidence interval [CI] 1.5-14.4; p = 0.012) and serum albumin ≤3.5 g/dl (OR 3.35, 95% CI 1.1-10.38, p = 0.012). The number of regular medications prescribed in patients with SSI (8.2 ± 5.4) was significantly more than that in patients without SSI (3.8 ± 4.4) (p = 0.001), and the cut-off value of the number of medications was 7, as derived from receiver operating characteristics analysis. Multivariate analysis revealed that the number of regular medications ≥7 was an independent risk factor significantly associated with SSIs (OR 7.3, 95% CI 2.3-24.0, p = 0.001). CONCLUSIONS: Our study demonstrated that an important risk factor for SSI after spinal instrumentation surgery was number of regular medications ≥7. Number of regular medications is a simple and valuable risk index for SSI, which reflects the influence of medications and comorbidities.

Natural history of the ossification of cervical posterior longitudinal ligament: a three dimensional analysis.

PURPOSE: Three-dimensional (3D) imaging using computed tomography (CT) has made it possible to accurately evaluate ossification of the posterior longitudinal ligament (OPLL). Recently, we developed a novel technique to measure ossification volume using the 3D analysis. The purpose of this study was to investigate the natural course of OPLL and the risk factors for volume progression. METHODS: Forty-one patients (22 males and 19 females) diagnosed with cervical OPLL who had been non-surgically treated were included in this study. We evaluated clinical examination, radiological findings, and the volume of ossified lesions during at least 1-year intervals. Furthermore, we performed risk factor analysis for OPLL volume progression. RESULTS: The mean ossification volume was 2047.4 ± 1437.3 mm3 in the first examination and 2201.0 ± 1524.1 mm3 in the final examination, indicating a significant increase during the follow-up period (p < 0.001). The mean annual rate of lesion increase was 4.1 ± 2.7%. Univariate regression analysis demonstrated significant relationships between the annual rate of lesion increase and age (ß = -0.48; p = 0.001), body weight (BW) (ß = 0.36; p = 0.02), and body mass index (BMI) (ß = 0.35; p = 0.03). Furthermore, age was the only significant predictor of OPLL progression (R2 = 0.23; p = 0.001) in multivariate liner regression analysis. CONCLUSIONS: Younger age, higher BW, and higher BMI are predictors of OPLL progression. Younger age is the most significant predictor in non-surgically treated patients.

Importance of computed tomography Hounsfield units in predicting S1 screw loosening after lumbosacral fusion.

We investigated whether computed tomography (CT) Hounsfield unit (HU) values of the S1 screw trajectory can predict screw loosening after lumbosacral fixation. We analysed 102 patients (58 men and 44 women) who underwent L5-S1 interbody fusion between April 2018 and October 2019. We reviewed the characteristics of patients including body mass index, smoking, comorbidity with diabetes mellitus, and interbody fusion types. Bone mineral density (BMD) was obtained from the lumbar spine and total hip using dual-energy X-ray absorptiometry. Additionally, we reviewed the S1 screw lengths and diameters. HU values of both L1 vertebral bodies and bilateral S1 screw trajectories were measured on preoperative CT. At six months postoperatively, S1 screws on CT were assessed. Screws with a 1 mm or more radiolucent zone were defined as "loosening". Seventeen patients had loosened screws, and 85 patients did not. The patient characteristics did not significantly differ between the two groups. Both total hip BMD and L1 HU values were low in the loosening patient group (both p = 0.03). Of the 204 total S1 screws, 25 screws were loosened, and 179 screws were not. The screw length was short (p = 0.01), and the HU value of the S1 screw trajectory was low (p < 0.001) in the loosening screw group. Based on receiver operating characteristic analyses of these factors, the area under the curve of HU value of the S1 screw trajectory was the highest (0.79). Measuring the HU value of both the L1 vertebral body and S1 screw trajectory aids in predicting screw loosening.

Gait Analysis by the Severity of Gait Disturbance in Patients with Compressive Cervical Myelopathy.

Introduction: Gait disturbance due to compressive cervical myelopathy has been previously described. However, data on how gait disturbance varies with the degree of lower extremity motor impairment are limited. Therefore, we investigated the characteristics of gait analysis based on severity and determined how gait disturbance progresses in compressive cervical myelopathy. Methods: We enrolled 44 patients (32 men and 12 women; mean age, 65.0 years) out of 108 consecutive patients with compressive cervical myelopathy who underwent spinal cord decompression surgery in our hospital. The exclusion criteria were inability to gait and complications affecting gait. Twenty-two patients with Japanese Orthopaedic Association scores 1 or 2 for lower extremity motor functions were assigned to the severe group, and 22 patients who scored 3 or 4 were assigned to the moderate group. Gait analysis was performed preoperatively using a long thin-type sensor sheet, and 25 healthy volunteers were assigned to the control group. Results: Stride length, swing phase, and gait speed decreased whereas step angle, stance phase, and double support duration increased as myelopathy progressed. Step width was significantly larger in the severe group than in the moderate and control groups. The cutoff values based on severe myelopathy with the inability to ascend or descend stairs without support were 60% for the stride length percentage of body height and 100 cm/s for gait speed. Conclusions: Decreases in stride length, swing phase, and gait speed and increases in step angle, stance phase, and double support duration are compensatory changes as cervical myelopathy progresses. Step width is a compensatory change that is not significantly altered in moderate myelopathy but increases when gait becomes affected, such that the patient cannot ascend or descend stairs without support.

Neoadjuvant teriparatide therapy targeting the osteoporotic spine: influence of administration period from the perspective of bone histomorphometry.

OBJECTIVE: Teriparatide (TPTD) is a potent promoter of early-stage osteogenesis and may be a useful adjuvant therapy to reduce complications related to bone fragility in spinal surgery patients with osteoporosis. However, effective neoadjuvant TPTD therapy regimens remain poorly understood. This study aimed to examine the effect of preoperative TPTD administration on cancellous bone with bone histomorphometry and to clarify the timing of preoperative TPTD administration for patients with spinal fusion and osteoporosis. METHODS: In this longitudinal multicenter study, 57 patients with spinal fusion and osteoporosis, who consented to undergo iliac biopsy, were allocated to the following treatment groups: neoadjuvant TPTD therapy group (n = 42) and no neoadjuvant therapy (NTC) group (n = 15). Patients in the TPTD group were categorized into subgroups on the basis of duration of preoperative TPTD administration, as follows: 1 month (n = 9), 2 months (n = 8), 3 months (n = 9), 4 months (n = 7), and 6 months (n = 9). All patient samples were preoperatively double labeled with tetracycline, and iliac biopsies were performed during spinal fusion surgery. Histomorphometric analyses were performed on nondecalcified, thin-sliced specimens. Specimens were classified on the basis of TPTD administration duration and subsequently compared with those of the NTC group. Postoperative complications and Oswestry Disability Index scores were evaluated at 1 and 2 years after surgery. RESULTS: There were no demographic differences between groups. Mineralizing surface/bone surface, a key parameter of dynamic bone formation, started to increase after 1 month of TPTD administration; this increase became significant after 3 months of administration and peaked at 4 months, with a 6-fold increase relative to that of the NTC group. The patients who received preoperative TPTD for 3 months or more had superior clinical results in terms of the osteoporotic complication rate and Oswestry Disability Index scores, except for bisphosphonate-pretreated patients. CONCLUSIONS: When considering neoadjuvant TPTD therapy, the authors recommend at least 3 months of preoperative administration to provide a more substantial anabolic effect from the early postoperative stage.

A case of advanced ankylosing spondylitis complicated with cervical myelopathy due to ossification of yellow ligament in which bone histomorphometry demonstrated delayed calcification.

There is minimal information available about bone histomorphometric findings in patients with ankylosing spondylitis (AS). Herein, we report a case of advanced AS complicated with cervical myelopathy due to ossification of yellow ligament (OYL). A 37-year-old Japanese man who had been diagnosed with AS was administered adalimumab. Thirty-four months after adalimumab treatment, he reported upper extremity numbness, dexterity impairment and a spastic gait. Magnetic resonance imaging and computed tomography of the cervical spine revealed cervical cord compression at the C5/6 level due to OYL. After surgery including posterior spinal fusion and cervical cord decompression with iliac bone graft at C5 and C6 arches, these symptoms improved. Bone histomorphometry of his ilium revealed marked osteoid formation and reduced mineral apposition, suggesting a calcification disorder. In addition, 25-hydroxy vitamin D was abnormally low (<4 ng/mL), and at 148 pg/mL parathyroid hormone was higher than the reference value, indicating secondary hyperparathyroidism. This case warrants reporting because OYL was complicated with AS and bone histomorphometric findings in AS were evaluated.

Health-Related Quality of Life in Nonoperated Patients With Adolescent Idiopathic Scoliosis in the Middle Years: A Mean 25-Year Follow-up Study.

STUDY DESIGN: A retrospective long-term follow-up study. OBJECTIVE: To investigate the health-related quality of life (HRQOL) status in middle-aged patients with adolescent idiopathic scoliosis (AIS) treated non-surgically. SUMMARY OF BACKGROUND DATA: The HRQOL status using various established questionnaires for non-operated AIS patients has not been fully investigated in long-term follow-up surveys. METHODS: Inclusion criteria were non-surgical treatment for AIS, more than or equl to 30° major scoliosis at skeletal maturity (Risser grade ≥4), and age more than or equl to 30 years at the time of the survey. A total of 107 AIS patients were included and divided into three groups (single main thoracic [MT] curve group; n = 50, single thoracolumbar/lumbar [TL/L] curve group; n = 19, and double-major [DM] curve group; n = 38) based on curve location at skeletal maturity. Age- and sex-matched volunteers were selected as the control group. RESULTS: There were no significant differences in age at survey, body mass index, bone mineral density of the femoral neck, and skeletal muscle mass index among the groups. In all groups, major scoliosis progressed by approximately 0.5°/yr from the time of skeletal maturity to the survey. The thoracolumbar (TL/L) and double-major (DM) groups showed significantly worse visual analog scale scores for low back pain compared with the main thoracice (MT) group (P < 0.05). The all-scoliosis groups showed significantly worse scores for self-image domain of the Scoliosis Research Society Outcome Instrument-22 (SRS-22) than the control group (P < 0.0001). The TL/L group showed significantly worse scores for walking ability and social function domains of the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) (P < 0.05). There were no significant differences in Oswestory Disability Index and Short-Form-12 among the four groups. CONCLUSION: AIS patients with single MT curve maintain equal HRQOL status compared with healthy controls. Patients with structural TL/L curves are likely to experience greater annual TL/L curve progression and have substantial low back pain or worse low back pain-specific HRQOL status during middle age. LEVEL OF EVIDENCE: 4.

A novel concept of posterior decompression and instrumented fusion with selective lordotic correction for cervical ossification of the posterior longitudinal ligament.

PURPOSE: The recovery rate of Japanese Orthopedic Association (JOA) score with K-line (-) cervical ossification of the posterior longitudinal ligament (OPLL) for posterior decompression with in-situ fusion (PDF) tends to be lower than that of anterior decompression with fusion (ADF). However, ADF is a technically demanding operation and has ADF-specific complications. This prospective report introduced a novel concept of PDF with selective lordotic correction as well as prophylactic foraminal decompression. METHODS: Six consecutive patients (four men and two women; mean age, 61.8 years) were included. PDF was performed, attempting to create cervical lordosis to acquire a posterior shift of the spinal cord, while preventing postoperative C5 palsy by prophylactic facetectomy and selective lordotic correction. RESULTS: The mean recovery rate of JOA score at the final follow-up was 70.9 ±â€¯20.3%. The mean C2-C7 angle preoperatively and at final follow-up was 5.5 ±â€¯3.9° and 12.2 ±â€¯4.8°, respectively. No symptomatic nerve root palsy, except one case with transient C7 root iatrogenic palsy, was found. CONCLUSIONS: A novel concept of PDF with selective lordotic correction obtained recovery rates of JOA scores comparable to those of ADF. We believe that this method can improve PDF outcomes in patients with K-line (-) OPLL.

The Natural Course of Compensatory Lumbar Curves in Nonoperated Patients With Thoracic Adolescent Idiopathic Scoliosis.

STUDY DESIGN: A retrospective, long-term follow-up study. OBJECTIVE: We investigated the natural course of compensatory lumbar curves in patients with primary thoracic adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: The natural course of compensatory lumbar curves in primary thoracic AIS remains unknown. METHODS: Inclusion criteria were right-sided primary thoracic AIS ≥30° with a Lenke lumbar modifier of A or B at skeletal maturity and ≥30 years of age at the time of the survey. Fifty-one patients (mean age, 40.2 yr) returned for a follow-up evaluation (follow-up rate, 34.2%). Patients were classified into three groups based on the lumbar modifier (A or B) and direction of L4 tilt [right (R) or left (L)] (AR, n.11; AL, n.18; and B, n.22). At the time of the survey, 42 patients underwent radiological examinations and 37 underwent lumbar magnetic resonance imaging. Quality of life questionnaires were completed in all patients and in a 1:1 matched control group (no history of scoliosis). RESULTS: The thoracic curves had significantly progressed in all patient groups, while the compensatory lumbar curve progressed only in the B group. The C7 translation and L4 tilt shifted to the right in the AR and AL groups, but did not change in the B group. As a result, the L4 tilt (median, 11°) and C7 translation (18.6 mm) tended to be the greatest in the AR group. The incidences of Modic changes at L4/5 discs and ≥3 cm on the visual analogue scale for low back pain were significantly higher in the AR group (77.8% and 54.5%, respectively) compared with that in the other groups. CONCLUSION: The natural course of compensatory lumbar curves is dependent on the lumbar modifier and direction of L4 tilt. Adolescent patients with right-sided primary thoracic AIS (≥30°) with L4 tilted to the right should be considered for periodic follow-ups into adulthood. LEVEL OF EVIDENCE: 4.

Long-term Impacts of Brace Treatment for Adolescent Idiopathic Scoliosis on Body Composition, Paraspinal Muscle Morphology, and Bone Mineral Density.

STUDY DESIGN: A retrospective, long-term follow-up study. OBJECTIVE: We aimed to investigate the long-term impacts of brace treatment for adolescent idiopathic scoliosis (AIS) on the musculoskeletal system. SUMMARY OF BACKGROUND DATA: Although full-time brace treatment is the mainstay of conservative treatment for AIS, the restrictive nature of brace treatment for lumbosacral motion might negatively affect the musculoskeletal system. METHODS: Of 319 patients treated nonoperatively for AIS, 80 patients completed clinical and imaging examinations. Body composition, including body fat mass, lean mass, fat percent, and muscle mass, was estimated via bioelectrical impedance analysis. Bone mineral density (BMD) was measured at the lumbar spine and left hip. In 73 patients, the measurement of cross-sectional area and fatty degeneration of paraspinal muscles at the superior endplate of L4 were performed using axial T2-weighted magnetic resonance imaging. Patients were divided into the full-time brace (FB; >13 hours per day) and nonfull-time brace (NFB; observation, part-time bracing, or drop out from FB within a year) groups. RESULTS: There were 44 patients in the FB group and 36 in the NFB group. Patients in the FB group were significantly younger at the initial visit (12.7 ±â€Š1.3 years) and older at the final follow-up (41.5 ±â€Š5.6 years) than those in the NFB group (14.2 ±â€Š3.2 and 37.4 ±â€Š7.1 years, respectively; P < 0.01). The rate of patients engaging in mild or moderate sports activity in adulthood tended to be higher in the FB group (47.7%) than in the NFB group (25%) (P = 0.11). However, there were no significant differences in body composition, paraspinal muscle morphology, and BMD between the two groups both before and after adjusting for age. CONCLUSION: Full-time brace wearing during adolescence did not have any negative impacts on the musculoskeletal system in adulthood. This information will be helpful for improving the compliance of full-time bracing. LEVEL OF EVIDENCE: 4.

Quantitative radiographic analysis of foraminal re-stenosis after posterior cervical foraminotomy with laminoplasty.

Few studies have performed detailed radiographic evaluation of the cause of recurrent cervical radiculopathy. In this study, we aimed to perform quantitative analyses of foraminal re-stenosis after posterior cervical foraminotomy (PCF) concomitant with laminoplasty. Seventy-eight consecutive patients (50 males and 28 females, mean age of 62 years at surgery) with cervical spondylotic radiculomyelopathy who underwent PCF concomitant with open-door laminoplasty were included. A total of 133 foramina undergoing PCF were radiographically evaluated using the following parameters: disc height, focal range of motion at the corresponding disc level, foraminal diameter (FD) and facet joint width (FJW) in the axial view on computed tomography, and re-stenosis rate (RR) of foramina. RR was calculated as follows: (foraminal regrowth at 2 years after surgery)/(foraminal enlargement immediate postoperatively) × 100% (RR2y). FDs preoperatively, postoperatively, and at 2-year follow-up were 2.2, 6.6, and 4.6 mm, respectively, and FJWs were 14.5, 9.0, and 10.6 mm, respectively. Both parameters significantly increased at the 2-year follow-up (p < 0.001). The mean RR2y was 42% (range, -16 to 108%). On logistic regression analysis of risk factors for higher RR2y (>50%), only preoperative posterior disc height (PDH) (OR = 0.33; 95% CI = 0.193-0.563; p < 0.001) was identified. Receiver operating characteristic curve analysis showed that the cut-off value of RR2y 50% was 1-mm PDH (AUC 0.73, sensitivity 52%, specificity 86%, p value < 0.001). After posterior foraminotomy with laminoplasty, the enlarged foraminal space gradually decreased during the 2-year follow-up. Foraminal re-stenosis was mainly due to bone regrowth of the resected facet joint, which is caused by disc degeneration with loss of PDH.

En Bloc Spondylectomy for Spinal Metastases: Detailed Oncological Outcomes at a Minimum of 2 Years after Surgery.

STUDY DESIGN: Retrospective case series. PURPOSE: To investigate the oncological outcomes, including distant relapse, after en bloc spondylectomy (EBS) for spinal metastases in patients with a minimum of 2-year follow-up. OVERVIEW OF LITERATURE: Although EBS has been reported to be locally curative and extend survival in select patients with spinal metastases, detailed reports regarding the control of distant relapse after EBS are lacking. METHODS: We conducted a retrospective review of 18 consecutive patients (median age at EBS, 62 years; range, 40-77 years) who underwent EBS for spinal metastases between 1991 and 2015. The primary cancer sites included the kidney (n=7), thyroid (n=4), liver (n=3), and other locations (n=4). Survival rates were estimated using the Kaplan-Meier method, and groups were compared using the log-rank method. RESULTS: The median operative time and intraoperative blood loss were 767.5 minutes and 2,375 g, respectively. Twelve patients (66.7%) experienced perioperative complications. Five patients (27.8%) experienced local recurrence of the tumor at a median of 12.5 months after EBS, four of which had a positive resection margin status. Thirteen patients (72.2%) experienced distant relapse at a median of 21 months after EBS. The estimated median survival period after distant relapse was 20 months (95% confidence interval, 0.71-39.29 months). No association was found between resection margin status and distant relapse. Overall, the 2-year, 5-year, and 10-year survival rates after EBS were 72.2%, 48.8%, and 27.1%, respectively. Importantly, the era in which EBS was performed did not impact the oncological outcomes. CONCLUSIONS: Our results suggest that EBS by itself, even if margin-free, cannot prevent further dissemination, which occurred in >70% of patients at a median of 21 months after EBS. These results should be considered and conveyed to patients for clinical decision-making.

Predicting Factors at Skeletal Maturity for Curve Progression and Low Back Pain in Adult Patients Treated Nonoperatively for Adolescent Idiopathic Scoliosis With Thoracolumbar/Lumbar Curves: A Mean 25-year Follow-up.

STUDY DESIGN: A retrospective, long-term follow-up study. OBJECTIVE: We aimed to clarify the predicting factors at skeletal maturity for future curve progression and low back pain (LBP) in adolescent idiopathic scoliosis (AIS) with thoracolumbar/lumbar (TL/L) curve. SUMMARY OF BACKGROUND DATA: TL/L curves are likely to progress after skeletal maturity and cause LBP. METHODS: Of 147 patients treated nonoperatively for AIS with TL/L curve, 56 (55 females; average age at the time of survey, 39.5 ±â€Š7.1 years; average follow-up duration after maturity, 24.9 ±â€Š6.9 years) completed questionnaires, including the visual analogue scale (VAS) for LBP and Oswestry disability index (ODI). Forty-nine patients underwent a radiological examination, and 48 underwent lumbar magnetic resonance imaging (MRI). RESULTS: The mean Cobb angle of the TL/L curve increased from 37.3°â€Š±â€Š7.5° to 47.8°â€Š±â€Š12.6° (0.41°â€Š±â€Š0.39° per year). The factors at skeletal maturity that were associated with the annual progression of the TL/L curve included a cranially located apical vertebra, and great apical vertebral translation and L3 tilt. In addition, the VAS for LBP was positively correlated with L4 tilt, and the ODI was positively correlated with L4 tilt and apical vertebral rotation. Multivariate analyses and receiver-operating characteristic curves demonstrated that L3 tilt at skeletal maturity independently predicted a curve progression ≥0.5° per year (odds ratio [OR], 1.17), while L4 tilt at skeletal maturity independently predicted a VAS ≥3 cm (OR, 1.20) and ODI ≥21% (OR, 1.25) in adulthood, with a cutoff value of approximately 16° for each factor. Moreover, lumbar disc degeneration on MRI was associated with L4 tilt at skeletal maturity and LBP in adulthood. CONCLUSION: Great L3 and L4 tilt at skeletal maturity, especially those >16°, are predictors of future curve progression and LBP in adulthood, respectively. For adolescent patients with these risk factors, periodic follow-ups into adulthood should be considered. LEVEL OF EVIDENCE: 4.

The Influence of Lumbar Muscle Volume on Curve Progression After Skeletal Maturity in Patients With Adolescent Idiopathic Scoliosis: A Long-Term Follow-up Study.

STUDY DESIGN: A retrospective cohort study. OBJECTIVES: To investigate the relationship between skeletal muscle status of the trunk and the progression of adolescent idiopathic scoliosis (AIS) during adulthood. SUMMARY OF BACKGROUND DATA: To date, studies evaluating the risk factors for progression of AIS have principally focused on radiographic parameters. METHODS: Eighty-two women with AIS managed conservatively, who had a major curve ≥30° at skeletal maturity (Risser grade ≥4), were enrolled. Patients had been followed-up, on average, over 23.5 years (range, 12-37 years) after skeletal maturity, and were ≥30-years-old at the time of the survey (mean, 40.1 years). The ratio of the cross-sectional area (CSA) and signal intensity (SI) of muscles (multifidus [MF], erector spinae [ES], and psoas major [PM]) were evaluated using axial T2-weighted magnetic resonance images at the level of L4. RESULTS: The mean progression of the main thoracic and thoracolumbar/lumbar (TL/L) curves after skeletal maturity was 8.2° (mean annual rate of 0.4°) and 7.2° (mean annual rate of 0.3°), respectively. The mean CSA ratio was as follows: MF, 23.3%; ES, 79.6%; and PM, 40.5%. The mean SI ratio was as follows: MF, 34.9%; ES, 31.7%; and PM, 20.9%. On multivariate logistic regression, a higher SI ratio of the MF was predictive of a progression of the Cobb angle and translation of the apical vertebra, with a lower CSA ratio of the ES contributing to the progression of the Cobb angle for the TL/L curve. CONCLUSIONS: In patients with AIS who have a major curve ≥30° at skeletal maturity, patients with greater TL/L curve progression have lower skeletal muscle volume and higher fatty degeneration of the lumbar extensor muscles in adulthood. However, further longitudinal or prospective studies are necessary to clarify the causal relationship between scoliosis progression and trunk muscular status. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

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

STUDY DESIGN: A retrospective, long-term follow-up study. OBJECTIVE: We investigated the incidence and risk factors for osteopenia at a minimum of 20 years after spinal instrumented fusion for adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: Surgically treated AIS patients may be likely to have osteopenia in adulthood because the association between AIS and osteopenia has been well documented. However, the long-term results of AIS surgery on BMD have not been evaluated. METHODS: Twenty-one (19 women; mean age, 45.3 years) of 45 consecutive patients with AIS who underwent spinal instrumented fusion surgery between 1973 and 1994 consented to inclusion in the current analysis. Based on their T scores for bone mineral density (BMD) of the left hip, participants were divided into an osteopenia/osteoporosis group (group P, T score < -1.0) and a normal group (group N, T score ≥ -1.0). Z scores of the left hip were used for analyses of the association between bone mineral status and individual factors. RESULTS: Eleven participants (52.4%) were categorized into group P. Mean body weight (kg) at survey (46.6 vs. 56.8) and mean body mass index (BMI) at both surgery (17.2 vs. 19.5) and survey (18.7 vs. 23.2) were significantly lower in group P than in group N (p < .05). Moreover, body weight at survey (Spearman rank correlation coefficient, rS = 0.49), as well as BMI at both surgery (rS = 0.67) and survey (rS = 0.61) demonstrated positive correlations with the Z-score (p < .05). CONCLUSION: More than half of the participants had osteopenia or osteoporosis, and both preoperative and postoperative low BMI were risk factors for osteopenia in adulthood. LEVEL OF EVIDENCE: Level IV.