Preoperative Scoring System for Prediction of Early Adjacent Vertebral Body Fracture After Balloon Kyphoplasty Using X-Rays Taken in a Non-Weight-Bearing Position.

BACKGROUND: Prevention of adjacent vertebral body fracture (AVF) following balloon kyphoplasty (BKP) is a key challenge. The objective of this study was to develop a scoring system that could be more extensively and effectively used to determine the surgical indications for BKP. METHODS: The study involved 101 patients aged 60 years or older who had undergone BKP. Logistic regression analysis was used to identify risk factors for early AVF within 2 months following BKP. Scoring was based on the odds ratio for risk factors, and cut-off values were determined from the receiver operating characteristics curve. The correlation between the total scores and the incidence of early AVF, and the area under the curve for the logistic regression model predicting early AVF using the scoring system were investigated. RESULTS: 29 cases (28.7%) experienced early AVF after BKP. The scoring system was created as follows: 1) age (<75 years: 0 points (P), ≥75 years: 1P), 2) number of previous vertebral fractures (0: 0P, 1 or more: 2P), and 3) local kyphosis (<7°: 0P, ≥7°: 1P). The total scores were found to be positively correlated with the incidence of early AVF (r = 0.976, P = 0.004). The area under the curve of the scoring system for predicting early AVF was 0.796. The incidence of early AVF was 4.2% at ≤1P and 44.3% at ≥2P (P < 0.001). CONCLUSIONS: A scoring system which can be applied to a broader patient population was developed. In cases where the total score is 2P or more, alternatives to BKP should be considered.

The Relationship Between Global Sagittal Balance and the Incidence of Early Adjacent Vertebral Fractures Following Balloon Kyphoplasty.

BACKGROUND: Recently, it is widely known that global sagittal balance (GSB) influences the postoperative outcome of the spine. The purpose of this study was to investigate the relationship between GSB and the incidence of early adjacent vertebral fracture (AVF) following balloon kyphoplasty (BKP). METHODS: This study included 96 patients (19 males, 77 females, mean age 77.4 ± 5.5 years) who underwent BKP for osteoporotic vertebral fracture and who were over 60-years-old. We investigated the effect of GSB on early AVF within 2 months after surgery. Of the 96 patients, 76 patients (16 males, 60 females, mean age 77.0 ± 5.4) underwent BKP at the thoracolumbar junction (T11-L2) and were investigated independently. After the two-group comparison, logistic regression analysis was performed. RESULTS: During the observation period (18.3 ± 14.7 months), 27 of 96 patients (28.1%) suffered AVF after BKP, and 24 of 96 patients (25.0%) suffered early AVF. In the logistic regression analysis, spinopelvic parameters were not detected as significant risk factors. In cases of BKP at the thoracolumbar junction (T11-L2), 24 of 76 patients (31.6%) suffered AVF after BKP during the observation period (15.3 ± 19.5 months), and 21 of 76 patients (27.6%) suffered early AVF. Logistic regression analysis detected pelvic tilt (PT): odds ratio 1.087 (P = 0.046∗) and local kyphosis: 1.147 (P = 0.003∗) as risk factors for early AVF. The cutoff value was PT≥29° from the receiver operating characteristics curve. CONCLUSIONS: At the thoracolumbar junction (T11-L2), PT ≥29° is one of the risk factors of early AVF following BKP.

Construct Validity and Reliability of the Japanese Version of the Lumbar Stiffness Disability Index.

STUDY DESIGN: Outcome study to determine the construct validity and reliability of the Japanese version of the Lumbar Stiffness Disability Index. OBJECTIVE: The aim of this study was to evaluate the psychometric measurement properties of the Japanese version of the Lumbar Stiffness Disability Index (J-LSDI) following lumbar spinal surgery in order to assess its construct validity and reliability. SUMMARY OF BACKGROUND DATA: The LSDI was designed and validated as a tool to assess functional impacts of lumbar spine stiffness and diminished spinal flexibility. A Japanese version has been developed, but its construct validity and reliability have not been evaluated. METHODS: A Pearson correlation coefficient was calculated using flexion and extension range of motion, Oswestry Disability Index (ODI) and Tampa Scale for Kinesiophobia (TSK) as external standards to evaluate construct validity. An intraclass correlation coefficient (ICC) and a Bland-Altman analysis were used to evaluate test-retest reliability. RESULTS: A total of 244 patients following lumbar spinal surgery participated in the study. Fifty one of the 244 patients participated in the reliability study. The ICC of the J-LSDI for test-retest reliability was 0.89 (95% confidence interval, 0.79-0.93). There was no systematic error found in the results of the Bland-Altman analysis. One hundred ninety-three of the 244 patients participated in the validity study. There were significant correlations between the J-LSDI and trunk flexion range of motion (r = -0.66), extension (r = -0.51), ODI (r = 0.62), and TSK (r = 0.38). CONCLUSION: The construct validity and reliability of the Japanese version of the LSDI were confirmed. The J-LSDI can be used to evaluate lumbar stiffness and associated disability in Japanese patients following lumbar spinal surgery.Level of Evidence: 2.

Factors Influencing Interbody Cage Subsidence Following Anterior Cervical Discectomy and Fusion.

STUDY DESIGN: This is a prospective study. OBJECTIVE: The purpose of this study was to analyze the factors influencing subsidence following anterior cervical discectomy and fusion (ACDF) using a stand-alone cage. SUMMARY OF BACKGROUND DATA: The relationship between cage subsidence and cage height and material has been reported in previous studies. METHODS: Clinical and radiologic data from 78 patients, 105 levels, undergoing single-level and 2-level ACDF without plates from 2007 to 2015 were collected prospectively. Patients were followed for at least 12 months after surgery. Radiographs were obtained preoperatively, at 1 week, and at 1, 3, 6, and 12 months postoperatively to determine the presence of fusion and cage subsidence. RESULTS: There was a correlation in cage height and subsidence (Spearman P<0.05). Cage subsidence was significantly shorter in the polyetheretherketone cages than in titanium cages (P<0.05). However, when cage height was <5 mm, the difference between the 2 groups was not significant. Large subsidence (>3 mm) was observed in 17 patients, 20 levels, many of whom exhibited sinking in the first month after surgery. CONCLUSIONS: The greater the cage height, the greater the risk of cage subsidence in ACDF. Polyetheretherketone cages are superior to titanium cages for the maintenance of intervertebral height in cases where cage height is >5.5 mm. LEVEL OF EVIDENCE: Level 3.

Compensatory mechanism of the spine after corrective surgery without lumbar-sacral fixation for traumatic thoracolumbar kyphotic spine deformity.

BACKGROUND: It remains unclear whether long fusion including lumbar-sacral fixation is needed in corrective surgery to obtain good global sagittal balance (GSB) for the treatment of traumatic thoracolumbar kyphotic spine deformity. The purposes of this study were to evaluate compensatory mechanism of the spine after corrective surgery without lumbar-sacral fixation and to evaluate the parameters affecting the achievement of good GSB post-operatively. METHODS: Twenty (20) subjects requiring corrective surgery (distal end of fixation was L3) were included in this study. The radiographic parameters were measured pre-operatively and at one month after surgery. Sagittal Vertical Axis (SVA), Lumber Lordosis angle altered by fracture (fLL), Thoracic Kyphosis angle altered by fracture (fTK), Pelvic Tilt (PT), Sacral Slope (SS), Pelvic Incidence (PI), Segmental Lumbar Lordosis (sLL: L3-S/L4-S), and local kyphotic angle were measured. The correlation between correction of local kyphotic angle (CLA) and the change in radiographic parameters was evaluated. Post-operatively, subjects with SVA<50 mm and PI-fLL<10°were regarded as the "good GSB group (G group). The radiographic parameters affecting the achievement of G group were statistically evaluated. RESULTS: fLL, sLL:L3-S and sLL:L4-S were decreased indirectly because the local kyphosis was corrected directly (CLA: 26.5 ± 8.6°) (P < 0.001). CLA and the change in fLL showed significant correlation (r = 0.821), the regression equation being: Y = -0.63X+3.31 (Y: The change in fLL, X: CLA). The radiographic parameters significantly affecting the achievement of G group were: SVA, PT, PI-fLL, sLL: L3-S, and sLL: L4-S (P < 0.01). CONCLUSION: The main compensatory mechanism was the decrease of lordosis in the lumbar spine. fLL was decreased to approximately 60% of CLA after surgery. SVA was not corrected by the compensatory mechanism.

Prevalence and risk factors of deep vein thrombosis in patients undergoing lumbar spine surgery.

BACKGROUND: Spinal surgery is classified as a moderate risk for DVT. The occurrence of DVT after various spinal surgical procedures was reviewed retrospectively, and the perioperative risk factors in the high-risk group were identified. In addition, the administration of the factor Xa inhibitor to DVT subjects with unstable thrombosis was evaluated to reveal its effectiveness in the prevention of PTE and postoperative complications. METHODS: This study included 588 subjects who underwent lumbar spine surgery. The patient population consisted of the following four groups: the fracture group (F group), the laminectomy group (La group), the TLIF group (T group), and the long fusion group (Lo group). Bilateral lower limb venous ultrasonography was performed on the day before surgery, the day after surgery, and one week after surgery. The incidence of DVT was determined for each group and potential risk factors were evaluated in the group with the highest incidence of DVT. Subjects with DVT who had unstable thrombosis received anticoagulant therapy (factor Xa inhibitor) and their treatment results were assessed. RESULTS: The overall incidence of DVT was 32.3% (190/588). A significantly high incidence of DVT was observed in the Lo group (54.3%; 75/138). Logistic regression and ROC analysis of potential risk factors in the Lo group identified a D-dimer value of 19.5 ug/ml at one week postoperatively as a risk factor of DVT (p = 0.02; odds ratio, 4.09; 95% CI, 2.82-7.88). Overall, 15.8% of subjects (30/190) received anticoagulant therapy. These subjects experienced neither PTE nor epidural hematoma. A follow-up ultrasonography performed at three weeks postoperatively detected the disappearance/resolution of DVT in 86.7% of these subjects (26/30). CONCLUSION: The incidence of DVT varied according to the invasiveness of the procedure. Successful management of DVT hinges on preoperative risk management involving prophylactic treatment and early diagnosis, in order to avoid PTE and other complications.