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Although autologous bone grafting is widely considered as an ideal source for interbody fusion, it still carries a risk of nonunion. The influence of the intervertebral device should not be overlooked. Requirements for artificial spinal devices are to join the vertebrae together and recover the original function of the spine rapidly. Ordered mineralization of apatite crystals on collagen accelerates bone functionalization during the healing process. Particularly, the stable spinal function requires the ingrowth of an ordered collagen and apatite matrix which mimics the intact intervertebral microstructure. This collagen and apatite ordering is imperative for functional bone regeneration, which has not been achieved using classical autologous grafting. We developed an intervertebral body device to achieve high stability between the host bone and synthesized bone by controlling the ordered collagen and apatite microstructure. This was an in vivo animal study. Intervertebral spacers with a through-pore grooved surface structure, referred to as a honeycomb tree structure, were produced using metal 3D printing. These spacers were implanted into normal sheep at the L2–L3 or L4–L5 disc levels. As a control group, grafting autologous bone was embedded. The mechanical integrity of the spacer/bone interface was evaluated through push-out tests. The spacer with honeycomb tree structure induced anisotropic trabecular bone growth with textured collagen and apatite orientation in the through-pore and groove directions. The push-out load of the spacer was significantly higher than that of the conventional autologous graft spacer. Moreover, the load was significantly correlated with the anisotropic texture of the newly formed bone matrix. The developed intervertebral spacer guided the regenerated bone matrix orientation of collagen and apatite, resulting in greater strength at the spacer/host bone interface than that obtained using a conventional gold-standard autologous bone graft. Our results provide a foundation for designing future spacers for interbody fusion in human. [ABSTRACT FROM AUTHOR]

Background Context: Although the results of decompression surgery for lumbar spinal canal stenosis (LSS) are favorable, it is still difficult to predict the postoperative health-related quality of life of patients before surgery.Purpose: The purpose of this study was to develop and validate a machine learning model to predict the postoperative outcome of decompression surgery for patients with LSS.Study Design/setting: A multicentered retrospective study.Patient Sample: A total of 848 patients who underwent decompression surgery for LSS at an academic hospital, tertiary center, and private hospital were included (age 71±9 years, 68% male, 91% LSS, level treated 1.8±0.8, operation time 69±37 minutes, blood loss 48±113 mL, and length of hospital stay 12±5 days).Outcome Measures: Baseline and 2 years postoperative health-related quality of life.Methods: The subjects were randomly assigned in a 7:3 ratio to a model building cohort and a testing cohort to test the models' accuracy. Twelve predictive algorithms using 68 preoperative factors were used to predict each domain of the Japanese Orthopedic Association Back Pain Evaluation Questionnaire and visual analog scale scores at 2 years postoperatively. The final predictive values were generated using an ensemble of the top five algorithms in prediction accuracy.Results: The correlation coefficients of the top algorithms for each domain established using the preoperative factors were excellent (correlation coefficient: 0.95-0.97 [relative error: 0.06-0.14]). The performance evaluation of each Japanese Orthopedic Association Back Pain Evaluation Questionnaire domain and visual analog scale score by the ensemble of the top five algorithms in the testing cohort was favorable (mean absolute error [MAE] 8.9-17.4, median difference [MD] 8.1-15.6/100 points), with the highest accuracy for mental status (MAE 8.9, MD 8.1) and the lowest for buttock and leg numbness (MAE 1.7, MD 1.6/10 points). A strong linear correlation was observed between the predicted and measured values (linear correlation 0.82-0.89), while 4% to 6% of the subjects had predicted values of greater than±3 standard deviations of the MAE.Conclusions: We successfully developed a machine learning model to predict the postoperative outcomes of decompression surgery for patients with LSS using patient data from three different institutions in three different settings. Thorough analyses for the subjects with deviations from the actual measured values may further improve the predictive probability of this model. [ABSTRACT FROM AUTHOR]

Background Context: The risk factors for radiographical adjacent segment disease (ASD) in patients with degenerative spondylolisthesis have been previously reported. However, there are only few reports on patients with spondylolytic spondylolisthesis who underwent single-level posterior lumbar interbody fusion (PLIF).Purpose: The study aimed to investigate the risk factors for radiographical ASD in patients with L5-S1 spondylolytic spondylolisthesis who underwent single-level PLIF.Study Design/setting: A retrospective study PATIENT SAMPLE: This study retrospectively reviewed 135 consecutive patients (91 men and 44 women) with symptomatic L5-S1 spondylolytic spondylolisthesis who underwent single-level PLIF.Outcome Measures: The pre- and postoperative (at the final follow-up) spinopelvic parameters, % slip, sacral slope, lumbar lordosis (LL), pelvic tilt, pelvic incidence (PI), PI minus LL (PI - LL), lumbosacral angle, C7 sagittal vertical axis, and thoracic kyphosis were measured using standing radiographs.Methods: Radiographical ASD was defined as disc height loss (>3 mm), increase of posterior angulation (>5°), or progression of spondylolisthesis (>3 mm) between the pre- and postoperative radiographs. Pfirrmann's classification was used to evaluate disc degeneration. The radiographical parameters and changes between the pre- and postoperative values were evaluated and compared for the non-ASD and ASD groups. Binary logistic regression analysis was performed to evaluate the adjusted associations between each potential explanatory variable and ASD development.Results: The radiographical ASD incidence was 11%. Additionally, 60% of the patients with ASD had radiographical ASD at 1 year and all cases of radiographical ASD in this follow-up period occurred within 3 years after the initial surgery. The mean period of ASD occurrence after initial surgery was 21.7 ± 12.6 months. No patients required reoperation for radiographical ASD. Multivariate analysis revealed that a preoperative (odds ratio [OR], 5.9; 95% confidence interval [CI], 1.2-28.9; p=.03) and a postoperative (OR, 6.5; 95% CI, 1.2-34.5; p=.03) PI - LL of ≥15° were risk factors for radiographical ASD.Conclusions: Pre- and postoperative PI - LL value mismatch was identified as significant independent risk factors for radiographical ASD in patients with L5-S1 spondylolytic spondylolisthesis. Obtaining larger lordosis at L5-S1 may be the key to preventing radiographical ASD. [ABSTRACT FROM AUTHOR]

Background Context: A previous study examined the short-term (2 years) outcomes of a short fusion strategy for Lenke type 5C curves. This strategy had a little less correction rate with no difference in coronal and sagittal balance and SRS-22 scores to those of a conventional strategy and was superior in operative time and intraoperative bleeding. However, its effectiveness in longer follow-up periods was unknown.Purpose: To assess midterm surgical outcomes of a short fusion strategy for adolescent idiopathic scoliosis (AIS) with Lenke type 5C curve, involving posterior correction and fusion surgery (PSF) using pedicle-screw constructs.Study Design: Retrospective case series.Patient Sample: Twenty-nine patients who underwent PSF for AIS with Lenke type 5C curve with a minimum 5-year follow-up.Outcome Measures: Radiographic parameters and SRS-22.Methods: We compared radiographic parameters and clinical outcomes between patients with an upper instrumented vertebra (UIV) at the end vertebra (EV) (n=12) and those treated by short fusion (S), with a UIV one level caudal to the EV (n=17).Results: A preoperative mean Cobb angle of 51.9±13.8° was corrected to 11.7±7.7° in the EV group, and an angle of 46.0±6.6° was corrected to 9.3±5.2° in the S group. The correction was maintained in both groups at the final follow-up, and the mean correction loss was 2.8±6.8° in the EV and 6.5±6.5° in the S group (p=.143). The mean correction rate at the final follow-up was not significantly different between the EV (71.4±11.8%) and S (64.9±13.7%) groups (p=.199). A Cobb angle of a thoracic curve was significantly improved immediately after surgery and maintained during the follow-up period in the both groups. Coronal and sagittal balance, thoracic kyphosis, lumbar lordosis, L4 tilt, UIV/LIV tilt, shoulder balance, and SRS-22 had no difference between the two groups.Conclusions: There was no difference in radiographic parameters and SRS-22 between patients treated with a UIV at the UEV and patients treated using a short fusion strategy, in which the UIV was one level caudal to the UEV. The short fusion strategy can be one of the alternatives in PSF for Lenke type 5C curves, at least in 5-year time frame. [ABSTRACT FROM AUTHOR]

Background Context: Spinal epidural lipomatosis (SEL) results from excess lumbar epidural fat (EF) accumulation that compresses the cauda equina or nerve roots. Guidelines for the therapeutic management of SEL are not currently available.Purpose: To elucidate the efficacy of lumbar decompression surgery in SEL.Study Design: Multicenter retrospective study.Patient Sample: A total of 288 consecutive patients who underwent posterior lumbar spinous-splitting decompression surgery for lumbar spinal canal stenosis and followed up greater than 2 years at participating institutions were retrospectively reviewed.Outcome Measures: Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) and Roland-Morris Disability Questionnaire (RDQ).Methods: Participants were divided into two groups according to the ratio of EF to anteroposterior diameter of the spinal canal (EF/SC-L) at the spinal level with maximum dural tube compression. Patients with EF/SC-L of ≥0.6 and <0.6 were defined as those with SEL and non-SEL, respectively. We assessed whether surgical treatment was "effective" or "not effective" using the JOABPEQ based on the following: an increase of ≥20 points in the postoperative score compared with the preoperative score, or a preoperative score <90 with a postoperative score ≥90 points. We constructed a multiple Poisson regression model by adjusting for confounding factors, and determined estimated relative risk (RR) for "not effective" with surgical treatment using the JOABPEQ. Additionally, we selected age-, sex-, BMI-, and decompression levels-matched patients with non-SEL and compared the frequency of "not effective" between SEL patients (n=60) and non-SEL patients (n=60).Results: Analysis using the RDQ and JOABPEQ showed that the 1- and 2-year postoperative scores were significantly better than the preoperative scores in the both groups. Multivariable Poisson regression analysis demonstrated that SEL was significantly associated with "not effective" for decompression surgery in the 1-year postoperative outcomes of walking ability ([RR] 1.5, 95% confidence interval [CI] 1.0-2.2) and social life (RR 1.3, 95% CI 1.0-1.8) and the 2-year postoperative outcomes of walking ability (RR 1.6, 95% CI 1.2-2.3). Matching analysis showed that SEL was significantly associated with "not effective" with lumbar decompression surgery in the 2-year postoperative outcomes of walking ability (p=.02).Conclusions: Patients with SEL exhibited significant improvements in surgical outcomes at 1 and 2 years postoperatively. However, compared with the non-SEL group, the efficacy of posterior lumbar spinous-splitting decompression surgery was worse in the SEL group, especially for walking ability. These results indicate that EF accumulation should be considered when planning treatment for patients with lumbar spinal canal stenosis and estimating the efficacy of lumbar decompression surgery. [ABSTRACT FROM AUTHOR]

Background Context: Corrective surgery for adult spinal deformity (ASD) improves health-related quality of life but has high complication rates. Predicting a patient's risk of perioperative and late postoperative complications is difficult, although several potential risk factors have been reported.Purpose: To establish an accurate, ASD-specific model for predicting the risk of postoperative complications, based on baseline demographic, radiographic, and surgical invasiveness data in a retrospective case series.Study Design/setting: Multicentered retrospective review and the surgical risk stratification.Patient Sample: One hundred fifty-one surgically treated ASD at our hospital for risk analysis and model building and 89 surgically treated ASD at 2 other our hospitals for model validation.Outcome Measures: HRQoL measures and surgical complications.Methods: We analyzed demographic and medical data, including complications, for 151 adults with ASD who underwent surgery at our hospital and were followed for at least 2years. Each surgical risk factor identified by univariate analyses was assigned a value based on its odds ratio, and the values of all risk factors were summed to obtain a surgical risk score (range 0-20). We stratified risk scores into grades (A-D) and analyzed their correlations with complications. We validated the model using data from 89 patients who underwent ASD surgery at two other hospitals.Results: Complications developed in 48% of the patients in the model-building cohort. Univariate analyses identified 10 demographic, physical, and surgical risk indicators, with odds ratios from 5.4 to 1.4, for complications. Our risk-grading system showed good calibration and discrimination in the validation cohort. The complication rate increased with and correlated well with the risk grade using receiver operating characteristic curves.Conclusions: This simple, ASD-specific model uses readily accessible indicators to predict a patient's risk of perioperative and postoperative complications and can help surgeons adjust treatment strategies for best outcomes in high-risk patients. [ABSTRACT FROM AUTHOR]

Background Context: Spinal epidural lipomatosis (SEL) is a condition in which excess lumbar epidural fat (EF) deposition often leads to compression of the cauda equina or nerve root. Although SEL is often observed in obese adults, no systematic research investigating the potential association between SEL and metabolic syndrome has been conducted.Purpose: To elucidate potential association between SEL and metabolic syndrome.Study Design: An observational study used data of a medical checkup.Patient Sample: We retrospectively reviewed data from consecutive subjects undergoing medical checkups. A total of 324 subjects (174 men and 150 women) were enrolled in this study.Outcome Measures: The correlation of EF accumulation with demographic data and metabolic-related factors was evaluated.Methods: The degree of EF accumulation was evaluated based on the axial views of lumbar magnetic resonance imaging. Visceral and subcutaneous fat areas were measured at the navel level using abdominal computed tomography. Metabolic syndrome was diagnosed according to the criteria of the Japanese Society of Internal Medicine. The correlation of SEL with metabolic syndrome and metabolic-related conditions was statistically evaluated.Results: The degree of EF accumulation demonstrated a significant correlation to body mass index, abdominal circumference, and visceral fat area. However, age, body fat percentage, and subcutaneous fat area showed no correlation with the degree of EF accumulation. Logistic regression analysis revealed that metabolic syndrome (odds ratio [OR]=3.8, 95% confidence interval [CI]=1.5-9.6) was significantly associated with SEL. Among the diagnostic criteria for metabolic syndrome, visceral fat area ≥100 cm2 (OR=4.8, 95% CI=1.5-15.3) and hypertension (OR=3.5, 95% CI=1.1-11.8) were observed to be independently associated with SEL.Conclusion: This is the first study to demonstrate that metabolic syndrome is associated with SEL in a relatively large, unbiased population. Our data suggest that metabolic-related conditions are potentially related to EF deposition and that SEL could be a previously unrecognized manifestation of metabolic syndrome. [ABSTRACT FROM AUTHOR]

Background Context: The relationship between gait pattern and the level of upper instrumented vertebra (UIV) in surgically treated patients with adult spinal deformity (ASD) has not been fully documented.Purpose: This study aimed to assess the effect of UIV level for the gait pattern in ASD.Study Design/setting: A prospective case series was carried out.Patient Sample: Thirty surgically treated consecutive female ASD with lumbosacral fusion (age 67.0±8.4 years; body mass index 22.7±2.4 kg/m2; Cobb angle 49.9°±21.3°; coronal vertical axis 1.5±3.6 cm; C7 sagittal vertical axis [C7SVA] 9.3±5.3 cm; pelvic incidence-lumbar lordosis 35.4°±25.8°; and lean volume of the lower leg 5.5±0.9 kg) were categorized into upper thoracic [UT] group or lower thoracic [LT] group based on the level of UIV (UT; UIV T2-T5, LT; UIV T9-T11), and the gait pattern were compared before and after corrective spine surgery.Outcome Measures: Scoliosis Research Society Patient Questionnaire, Oswestry Disability Index, and force plate analysis were the outcome measures.Methods: All subjects underwent gait analysis on a custom-built force plate. Dual-energy X-ray absorptiometry. Subjects were followed-up for at least 2 years postoperation.Results: The UT group had larger baseline Cobb angle, whereas the LT group had larger C7SVA (UT vs. LT; Cobb angle: 59.2±22.9 vs. 44.6±17.4°, p=.03, C7SVA: 10.9±8.7 vs. 12.0±7.1 cm, p=.03). Preoperatively, no difference was found in gait velocity and stride between UT and LT group, whereas the right and left difference of step length was significantly large in UT group (velocity: 55.0±12.5 vs. 53.6±9.0 m/min, stride: 99.7±13.0 vs. 97.8±13.6 cm, step length; 10.4±4.9 vs. 5.6%±3.3%). Coronal and sagittal alignments were significantly improved in both groups (total; Cobb angle: 19.4°±10.6°, C7SVA: 5.3±2.9 cm, PI-LL: 12.1°±5.1°). Gait pattern, stride, and velocity all improved significantly after surgery (total; velocity: 62.3±8.9m/min, stride: 106.8±12.3 cm, p=.01). The knee angle at the heel contact phase and hip range of motion (ROM) were also significantly improved at postoperation (total; hip ROM: preoperation: 29.2°±9.1°, postoperation: 36.2°±4.8°, knee angle; preoperation: 10.6°±6.6°, postoperation: 4.4°±2.8°). No difference was observed for the pelvis and shoulder rotation on the horizontal plane at postoperation in both groups (total; pelvis rotation; preoperation: 7.4°±3.4°, postoperation: 7.9°±2.4°, shoulder rotation; preoperation: 7.4°±2.9°, postoperation: 8.7°±3.6°). The head vertical deviation was also not changed postoperatively in both groups (preoperation: 3.1±0.9 cm, postoperation: 3.1±0.8 cm).Conclusions: Both UT and LT groups achieved similar improvement of gait ability and pattern after surgery. Additional studies will be needed to further define the effect of UIV for the activity of daily living such as fast walking, stepping the stairs, or standing from the chair in ASDs. [ABSTRACT FROM AUTHOR]

Background Context: Various factors are reported to affect the spinal alignment in degenerative lumbar scoliosis (DLS). Although trunk muscles also appear to affect spinal alignment, the role of the trunk muscles is not yet clear.Purpose: The aim was to elucidate the role of the multifidus (MF) and psoas (PS) in maintaining global spinal alignment in patients with DLS.Study Design: This was a multicenter retrospective matched cohort study.Patient Sample: Surgically treated 60 paired DLS and lumbar spinal stenosis (LSS) female (120 patients), matched for age and body mass index (BMI; DLS age 68.0±6.8 vs. LSS 67.1±8.9 years; BMI 21.6±3.3 vs. 23.2±3.8 kg/m(2)), were included and were followed for at least 2 years.Outcome Measures: Spinal alignment, muscle area, and volume were measured from radiographs, magnetic resonance images (MRIs), and whole-body dual-energy X-ray absorptiometry (DXA) scans. Muscle strength was measured by grip power and peak expiratory flow (PEF).Methods: As a surrogate of muscle area, we obtained the cross-sectional area (CSA) at the L5-S level from preoperative MRIs.Results: The MF and PS CSAs were significantly smaller in the DLS group than in the LSS group (MF 477.7±192.5 vs. 779.8±248.6 mm(2), p<.01; PS 692.3±201.2 vs. 943.4±272.4 mm(2), p=.002), whereas percentage of difference between the right and left sides was significantly larger in the DLS group (MF 18.4±30.6 vs. 2.4±3.3%, p<.01; PS 14.4±15.8 vs. 2.1±2.2%, p<.01). In the extremities, there were no significant differences in the left- or right-side lean composition and grip strength or PEF tests between the groups. Correlation coefficient tests showed moderate correlations between the MF average CSA (avCSA) and global spinal alignment and spinopelvic alignment (pelvic incidence-lumbar lordosis; R=-0.37, -0.38) in the DLS group. The MF avCSA was correlated with the postoperative progression of kyphosis at the unfused thoracic vertebrae in the DLS group (R=0.34).Conclusions: The CSAs of the MF and PS were significantly smaller in the DLS group. Whole-body DXA showed no significant difference in the lean composition between the groups. There were significant correlations in the DLS patients between the MF CSA and sagittal spinal alignment. These findings suggest the causal relationship between muscles and global spine alignment. [ABSTRACT FROM AUTHOR]

Favorable clinical outcomes have been described for elective spine surgery in patients with LSS. However, the way preoperative motor weakness (MW) affects the patient's health-related quality of life (HRQoL) after surgery is not well understood. This study sought to determine how baseline MW affects elective spine surgery in patients with degenerative lumbar spinal stenosis (LSS). Single center retrospective case series. This study included 305 surgically treated patients with LSS who had 2-year follow-up (age 71±9 years, male 62%). Demographic, radiographic, and clinical outcomes were analyzed. The Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) was used to assess the HRQoLs at baseline and at 1-year, 2-year, and 3-year postoperation. The HRQoLs were compared between those with or without preop MW. Adjusted multivariate logistic regression analyses (MRAs) were performed to determine whether MW affected HRQoLs. A total of 116 patients (38%) were categorized as MW+. The patient background including age, sex, presence of degenerative spondylolisthesis, type of surgery, and presence of neurological claudication were similar between the 2 groups. However, the 1-, 2-, and 3-year postoperative VAS of back pain, leg pain, leg numbness, JOABPEQ lumbar function, social life, mental health, and walking ability were all inferior in the MW+ group, whereas a similar percentage of patients achieved a minimum clinically important difference in all subdomains at 3 years. The adjusted MRA showed that having ≥2 muscles with MW, and severity of MW (MMT grade) were independent risk factors for both difficulty climbing stairs and walking >15 minutes (muscles with MW≥2; stair climbing: OR 6.4[2.3-17.4], walking: OR 3.2[1.4-7.3], severity of MW; stair climbing: OR 2.5[1.4-4.4], walking:OR 2.2[1.3-3.7]). The patients with baseline MW had inferior HRQoL for up to 3 years compared to that of those without MW; however, the amount of improvement in HRQoL was comparable. Timely follow-up is important to determine the deterioration of motor function. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Background context Parkinson's disease (PD) is a progressive degenerative disorder of the central nervous system. Patients with PD often present with abnormal posturing. Purpose To investigate coronal plane deformities in patients with PD, and to evaluate the correlation between clinical features, coronal parameters related to spine alignment, and disease severity. Study design A cross-sectional study. Patient sample Eighty-nine patients with PD and 89 controls were included. Outcome measures A medical history was collected from the medical records. Methods This study was a prospective assessment of consecutive patients with PD. Clinical and demographic parameters were collected from medical records and outpatient interviews. Full-length standing anteroposterior and lateral spine radiographs were used to assess the spinal parameters. The threshold for scoliosis was set at a 10° Cobb angle, and the curve type was classified using Schwab classification. Results A total of 178 patients (89 in PD and 89 in control groups) were included. Scoliosis was identified in 27 patients (30%) and 22 controls (p=.502). However, coronal imbalance was more common in patients with PD than in controls (11 vs. 0 patients, p=.001). Scoliosis was more common in women than in men (male:female=8:19, p=.04). Back pain was more common in patients with scoliosis than in those without scoliosis (14 of 27 vs. 17 of 62, p=.036). Schwab Type IV (thoracolumbar major) was the most common type of scoliosis in patients with PD and Type V (lumbar major) was the most common type in controls. With adjustment for patient age and gender, multiple linear regression analysis revealed that severity of PD (Unified Parkinson's Disease Rating Scale, p=.037) and magnitude of global coronal malalignment (p=.003) were associated with the scoliosis Cobb angle (p=.037, B=0.139). Direction of scoliosis and side of global coronal malalignment were not significantly correlated with the laterality of predominant PD symptoms (p>.05). Conclusions Global coronal malalignment is more prevalent in patients with PD than in controls. Greater severity of PD was significantly associated with greater magnitude of scoliosis Cobb angle, even after adjusting for the effects of patient age and gender. However, direction of scoliosis and side of global coronal malalignment were not significantly associated with the dominant laterality of PD symptoms. [ABSTRACT FROM AUTHOR]

BACKGROUND CONTEXT: Threaded cage technology has had a meteoric rise in usage. It has been touted as a procedure with low risk and minimal complications.PURPOSE: To gauge the spine surgical community''s general consensus regarding cage usage and its complications.STUDY DESIGN/SETTING: A canvassing questionnaire regarding threaded cage usage and complications was sent to members of the North American Spine Society.PATIENT SAMPLE: A total of 665 doctors reported on their perception of 22,585 cages placed by the second year after pre-market approval from the Food and Drug Administration approval.OUTCOME MEASURES: A nonscientific canvassing questionnaire was thought to give a consensus of surgical outcome perception in a large number of caregivers with hopes of understanding general trends.METHODS: Simple statistical measurements were used to report perceived complications by surgeons involved in performing threaded cage surgical procedures.RESULTS: Sixty-nine percent of doctors reported at least one complication with threaded cages, but the complication incidence was low. Visceral injuries were reported in 0.1%; vascular injuries, 1.0%; cage displacement and dislodgement, 1.4%; temporary and permanent neurologic injuries, 2.25% and 0.56%, respectively; infection 0.34%; retrograde ejaculation 1.2% and revision surgery recorded for 2.7%. Those rating cages as fair to poor (16.5%) were those physicians reporting the longest experience with this technology.CONCLUSIONS: The general consensus is that threaded cages have low complication rates and high satisfaction rates, 83.5%. The data represent a convenience sampling and is not scientific. [Copyright &y& Elsevier]

BACKGROUND CONTEXT As anchors for defining minimum clinical important difference (MCID) thresholds are determined by individual values, we sought to evaluate if MCID thresholds can be affected by cultural differences. PURPOSE The purpose of this study was to compare the MCID threshold and the proportion of adult spinal deformity (ASD) patients achieving SRS-22R MCID in North America (NA) versus Japan (Jp). STUDY DESIGN/SETTING Retrospective review of prospectively collected data. PATIENT SAMPLE Two hundred-eight cases [NA; 148 cases (male 16, female 132, average 59.8years old), Jp; 60 cases (male 4, female 56, average 65.5years old)] who followed for at least more than 2years after corrective fixation surgery for ASD patients with coronal Cobb angle of over 30° and over 40years old. OUTCOME MEASURES SRS22R MCID thresholds. METHODS There were 148 cases from NA (132 females, mean age=59.8 years) and 60 cases from Jp (56 females, mean age=65.5 years) with at least 2-year follow-up after corrective spine surgery for ASD. Except for self-image, published Jp MCID values are higher (function=0.90, pain=0.85 and self-image=1.05, subtotal=1.05) than the published NA MCID values (function=0.60, pain=0.40, self-image=1.23, subtotal=0.43). RESULTS There was statistically significant improvement in all domain scores at 2-year follow-up compared to baseline in both cohorts. Except for mental health (NA:0.32, Jp:0.72, p=.005), the mean improvement from baseline to 2 years was similar between the North American and Japanese cohorts. Except for self-image (NA:57%, Jp:58%, p=.877), the proportion of patients achieving MCID was higher in North America for function (NA:51%, Jp:30%, p=.006), pain (NA:80%, Jp:47%, p<.001), and subtotal (NA:72%, Jp:35%, p<.001). CONCLUSIONS Despite similar improvements in SRS22R domain scores from baseline to 2years postop, the proportion of patients reaching SRS22R MCID for function, pain and subtotal after ASD surgery are higher in a North American cohort compared to a Japanese cohort. This may imply that patients in North America and Japan may regard the value of these changes differently. [ABSTRACT FROM AUTHOR]

BACKGROUND CONTEXT Proximal junctional failure (PJF) is one of the most devastating complications in the surgical treatment of adult spinal deformity (ASD). There are cultural differences between Eastern and Western countries that may impact the incidence and risk factors for developing PJF. Therefore, international comparisons of the incidence and risk factors for PJF following ASD surgery can provide insight into the pathology of PJF. PURPOSE To assess whether cultural differences can impact the incidence and risk factors for developing PJF following surgery for ASD based on patients from Japan (JP) and the United States (US). STUDY DESIGN/SETTING Multicenter retrospective case series. PATIENT SAMPLE A total of 509 ASD patients surgically treated for ASD from JP and US. OUTCOME MEASURES Incidence of PJF and revision for PJF. METHODS A total of 136 JP and 373 US ASD patients with age>40 years with minimum 2-year follow-up following corrective surgery were analyzed. Radiographic and demographic data were compared. Outcome measures included ODI and SRS22. PJF was defined as either an increase from baseline of proximal junctional angle ≥20° with concomitant deterioration of at least one SRS-Schwab sagittal modifier grade from immediate postoperation or any type of PJK requiring revision. RESULTS A total of 509 patients were analyzed (JP vs. US women: 94% vs 80%; age: 64.3 years vs 62.7 years; BMI: 22.2 vs 27.8). Significantly worse baseline spinopelvic alignment was observed in JP (PI-LL: 36° ± 24° vs 19° ±21°). JP and US patients had similar incidence of PJF (17.6% vs 18.8%; p=.46), but revision surgery was more commonly performed in the US (5.1% vs 2.2%; p=.02). No differences were observed for ODI and SRS22 clinical outcomes between non-PJF patients and conservatively treated PJF patients in both JP and US (p>.05). Age and baseline thoracic kyphosis were both significantly greater in PJF patients compared with non PJF patients in both countries (p<.03). Baseline C7SVA and thoracolumbar kyphosis and amount of LL and C7SVA correction were significantly greater in PJF patients in the US, whereas number of patients with LIV at the pelvis and baseline PT were significantly greater in PJF patients in JP. CONCLUSIONS The incidence of PJF following ASD surgery was similar in the US and JP, whereas revision surgery for PJF was more commonly performed in the US. Greater age and baseline thoracic kyphosis were risk factors for PJF in both US and JP, whereas baseline sagittal alignment and its compensatory mechanisms had different impact on developing PJF between JP and US patients. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]