Recovery of the Japanese orthopedic association back pain evaluation questionnaire score and walking ability following lumbar spinal stenosis surgery.

PURPOSE: We investigated the recovery of the Japanese orthopedic association back pain evaluation questionnaire (JOABPEQ) scores and 6 min walk distance (6MWD) in patients after surgery for lumbar spinal stenosis and identified the items among 25 questions of JOABPEQ that showed recovery. METHODS: A total of 227 patients (average age 71.5 years; SD: 7.5; 121 men) were included from a single center. The outcome measures were JOABPEQ, visual analog scale (VAS), and 6MWD and obtained preoperatively and at 1, 3, 6, and 12 months postoperatively. Mixed-model repeated measures were used to compare the variables at each time point between the surgery groups. RESULTS: The JOABPEQ, VAS, and 6MWD scores generally improved at 1 month postoperatively compared with those obtained preoperatively, and some parameters further improved at 3 months. However, improvement in the lumbar spine dysfunction item of JOABPEQ was delayed, showing improvement at 3 months postoperatively for decompression surgery (average score: pre, 64.6; 3 months, 78.5) and 6 months postoperatively for fusion surgery (average score: Pre, 64.3; 6 months, 77.1). Responses to the individual JOABPEQ questions generally improved after surgery. No significant changes in lumbar spine dysfunction occurred in the fusion group. CONCLUSION: Our results demonstrated the early postoperative recovery course of JOABPEQ and 6MWD. In the fusion group, significant changes in lumbar spine dysfunction started at 6 months postoperatively. These findings could help medical staff explain postoperative recovery to patients after lumbar spinal stenosis surgery and in their decision making regarding surgery.

Wear characteristics of resin-based luting agents used in the bonded CAD-CAM resin blocks.

This study aimed to investigate the wear and microhardness of luting agents and computer-aided design-computer-aided manufacturing (CAD-CAM) resin blocks, and to compare the wear characteristics of resin-based luting agents used in bonded specimens of CAD-CAM resin blocks. After three-body wear test, the amount of wear and Vickers hardness were measured and Pearson's correlation coefficient was calculated. The lowest amount of wear and the highest Vickers hardness values were obtained for Estecem II. Filler loss was observed in five composite resin cements. A strong negative correlation was observed in the luting agents between the amount of wear and Vickers hardness value (r=-0.874, p<0.0001). Additionally, a strong positive correlation was observed between the amount of wear of the bonded specimen and amount of luting agent used alone (r=0.943, p<0.0001). To conclude, the wear resistance of the luting agent used in the bonded specimen was significantly influenced by the bonding between the filler and matrix resin.

Minimal Clinically Important Difference of the 6-Minute Walk Distance in Patients Undergoing Lumbar Spinal Canal Stenosis Surgery: 12 Months Follow-Up.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVE: We evaluated the responsiveness of the 6-minute walk distance (6MWD) and determined the threshold of the minimal clinically important difference (MCID) in patients who underwent lumbar spinal stenosis (LSS) surgery. SUMMARY OF BACKGROUND DATA: Little evidence exists on the MCID of 6MWD after LSS surgery. The 6MWD is an objective gait assessment that can be measured quickly. MATERIALS AND METHODS: In total, 126 patients (74 men; average age, 72.2 ± 6.5 yr) were included and assessed preoperatively and at 12 months postoperatively. We used the Oswestry Disability Index (ODI), as an anchor to calculate the MCID for the 6MWD and measured internal and external responsiveness of the 6MWD. The external responsiveness was assessed in 2 ways: (1) One based on the anchoring questionnaire and (2) another based on the scale distribution. The anchor-based approach was evaluated using the Spearman rank correlation coefficient and receiver-operating characteristic curve. The distribution-based approach was evaluated using the minimal detectable change. RESULTS: The ODI scores and 6MWD for each anchor significantly improved postoperatively. The change in the 6MWD was significantly correlated with change in the ODI (6 mo, r = -0.45; 12 mo, r = -0.49). The receiver-operating characteristic analysis demonstrated good discriminative properties for the 6MWD using the ODI anchor (6 mo, 0.72; 12 mo, 0.78). The cutoff values for 6MWD were 102.3 and 57.5 at 6 and 12 months, respectively. In the distribution-based approach, the minimal detectable change for the 6MWD was 95.7 m. CONCLUSIONS: We validated both the internal and external responsiveness of the 6MWD using the ODI and estimated the MCID in the 6MWD for patients undergoing LSS surgery. However, there was lower validity for the MCID among those participants with the high walking ability and low disability at baseline.

Effects of ceramic microbeads on bonding between a zirconia framework and layered resin composite.

This study was conducted to evaluate the effects of ceramic microbeads on the bond strength between resin and zirconia. Microbeads made of zirconia (TZ) and zircon (ZS) were treated with and without hydrofluoric acid (HF). The microbeads were sintered to zirconia disks using intermediate feldspathic porcelains. Two control groups, NB (without microbeads) and AS (without porcelain and microbeads), were also prepared. All specimens were treated with a phosphate primer and veneered with a light-curing resin composite. The 24-h shear bond strengths were determined and analyzed by the Tukey-Kramer test (α=0.05, n=10). The TZ-HF specimen exhibited the highest bond strength, followed by TZ, ZS-HF, ZS, AS, and NB. Scanning electron microscopy observations revealed that the TZ-HF specimen had a complicated debonded surface, and it included microconcavities where the microbeads were detached. Sintering etched zirconia beads onto a zirconia framework with feldspathic porcelains is useful for bonding layered resin composite materials.

Responsiveness and Minimal Clinically Important Difference of the 6-minute Walk Distance in Patients Undergoing Lumbar Spinal Canal Stenosis Surgery.

STUDY DESIGN: This was a retrospective review of prospectively collected data. OBJECTIVE: We aimed to evaluate the responsiveness of the 6-minute walk distance (6MWD) and determine the threshold of the minimal clinically important difference (MCID) in the 6MWD in patients who underwent surgery for lumbar spinal canal stenosis (LSS) surgery. SUMMARY OF BACKGROUND DATA: The 6MWD rapidly and objectively assesses the walking distance in patients with LSS. To date, no study has assessed the MCID in the 6MWD in patients who underwent LSS surgery. MATERIALS AND METHODS: A total of 41 patients (16 women; average age: 69.4 y, SD: 7.8 y) were included and assessed preoperatively and at 6 months postoperatively. We evaluated the 6MWD and Oswestry Disability Index (ODI), which is a health-related patientrReported outcome, used as an anchor to calculate the MCID for in the 6MWD. We used 2 different approaches to examine the responsiveness of the 6MWD: internal and external responsiveness. The external responsiveness was assessed in 2 ways: one based on the anchoring questionnaire and the other based on the scale distribution of the scale. The anchor-based approach was evaluated using the Spearman rank correlation coefficient and the receiver operating characteristic curve. The distribution-based approach was evaluated using the minimal detectable change. RESULTS: The ODI scores and 6MWD for each anchor significantly improved postoperatively. The correlation coefficient between changes in the 6MWD and ODI was r=-0.58. The area under the receiver operating characteristic curve for the ODI anchor was 0.70 (95% confidence interval: 0.52-0.89), and the cutoff value for the ODI anchor was 50 m (sensitivity=0.57, specificity=0.71). In the distribution-based approach, the minimal detectable change for the 6MWD was 105.9 m. CONCLUSIONS: Both the internal and the external responsiveness of the 6MWD were validated using the ODI. Therefore, the MCID in the 6MWD in patients undergoing LSS surgery ranges from 50 to 105.9 m. LEVEL OF EVIDENCE: Level III.

Relationship between changes in physical function parameters and Roland-Morris disability questionnaire score after decompression surgery for lumbar spinal canal stenosis.

Although decompression surgery for lumbar spinal canal stenosis (LSS) improves leg symptoms, low back pain (LBP), and disability, the factors related to the improvement of subjective disability have not been studied sufficiently. The purpose of the study was to clarify the relationship between subjective disability and objective physical function parameters. A total of 51 patients who underwent decompression were included and evaluated preoperatively and 6 and 12 months postoperatively. Patient-reported outcomes related to activity limitation due to LBP were evaluated using Roland-Morris disability questionnaire (RDQ) and VAS (Visual Analog Scale). Physical function was assessed using 6-min walk distance (6MWD) and trunk muscle strength. Univariate analysis and multivariable linear regression analysis were performed to identify significant factors for RDQ score change. The 6- and 12-month postoperative RDQ scores, VAS scores, and trunk extensor strength significantly improved relative to the preoperative values. In the univariate analysis, age, changes in VAS (LBP, leg pain, and numbness) scores, and change in 6MWD were associated with the RDQ score change (p < 0.05). Multivariable linear regression showed that 6MWD changes were significantly associated with RDQ score changes, explaining 41% of the variance in the RDQ score change. This study showed the change in 6MWD was significantly associated with the RDQ score change. Our results suggest that improving 6MWD may reduce disability in activities of daily living.

Effects of dimensions of laser-milled grid-like microslits on shear bond strength between porcelain or indirect composite resin and zirconia.

PURPOSE: Zirconia cores and frameworks are widely used in restorative dentistry. Although these structures are veneered with porcelain for esthetic reasons, the use of indirect composite resins (ICRs) is expected to increase in the future. The purpose of this study was to investigate the effects of microslits of different dimensions formed by Nd:YVO4 laser machining on the bond strength between two types of zirconia (3 mol% yttria-partially stabilized zirconia (Y-TZP) and ceria-partially stabilized zirconia/alumina nanocomposite (Ce-TZP/A)) and porcelain or an ICR. METHODS: The zirconia disks were assigned as follows: 1) blasted with alumina particles (AB) and 2-4) surface machined with gridded microslits with a width, pitch, and depth of 50, 75, or 100 µm (MS50, MS75, and MS100, respectively). After the bonding of the veneering materials to the disks, half of the specimens veneered with the ICR were subjected to thermocycling (4-60°C, 20000 cycles). All the specimens were subsequently shear tested (n = 10/group). RESULTS: There was no significant difference between the groups of the disks bonded to porcelain. On the other hand, for the disks bonded to the ICR, the bond strengths of the MS groups after thermocycling were statistically higher than that of the AB group. However, there was no significant difference in the bond strengths of the disks with different microslits. CONCLUSION: Within the study limitations, it can be concluded that, for porcelain, the design of the mechanical retentive structure must be modified. However, for the investigated ICR, a simple gridded pattern can improve the bond strength with zirconia.

Laser-Milled Microslits Improve the Bonding Strength of Acrylic Resin to Zirconia Ceramics.

Heightened aesthetic considerations in modern dentistry have generated increased interest in metal-free "zirconia-supported dentures." The lifespan of the denture is largely determined by the strength of adhesion between zirconia and the acrylic resin. Thus, the effect on shear bond strength (SBS) was investigated by using an acrylic resin on two types of zirconia ceramics with differently sized microslits. Micromechanical reticular retention was created on the zirconia surface as the novel treatment (microslits (MS)), and air-abrasion was used as the control (CON). All samples were primed prior to acrylic resin polymerization. After the resin was cured, the SBS was tested. The obtained data were analyzed by using multivariate analysis of variance(α = 0.05). After the SBS test, the interface failure modes were observed by scanning electron microscopy. The MS exhibited significantly higher bond strength after thermal cycles (p < 0.05) than the CON. Nevertheless, statistically comparisons resulted in no significant effect of the differently sized microslits on SBS (p > 0.05). Additionally, MS (before thermal cycles: 34.8 ± 3.6 to 35.7 ± 4.0 MPa; after thermal cycles: 26.9 ± 3.1 to 32.6 ± 3.3 MPa) demonstrated greater SBS and bonding durability than that of CON (before thermal cycles: 17.3 ± 4.7 to 17.9 ± 5.8 MPa; after thermal cycles: 1.0 ± 0.3 to 1.7 ± 1.1 MPa), confirming that the micromechanical retention with laser-milled microslits was effective at enhancing the bonding strength and durability of the acrylic resin and zirconia. Polycrystalline zirconia-based ceramics are a newly accessible material for improving removable prosthodontic treatment, as the bond strength with acrylic resin can be greatly enhanced by laser milling.

Association between Trunk Muscle Strength, Lumbar Spine Bone Mineral Density, Lumbar Scoliosis Angle, and Skeletal Muscle Volume and Locomotive Syndrome in Elderly Individuals: A Dual-Energy X-ray Absorptiometry Study.

INTRODUCTION: The present study aimed to investigate the association between trunk muscle strength, lumbar spine bone mineral density (BMD), lumbar scoliosis angle (LSA), and appendicular skeletal muscle mass index (ASMI) and the severity locomotive syndrome (LS) using dual-energy X-ray absorptiometry (DXA) technology in elderly individuals. METHODS: In this cross-sectional study, we enrolled 168 individuals aged >60 years. We measured their trunk muscle strength (flexion and extension) and BMD, LSA, and ASMI using DXA. We defined degenerative lumbar scoliosis (DLS) as LSA ≥ 10° by the Cobb method using the DXA image. The locomotor function was evaluated using the timed up-and-go (TUG) test and the 25-question Geriatric Locomotive Function Scale (GLFS-25) score. Normal locomotor function, LS-1, and LS-2 were defined as a GLFS-25 score of <7, ≥7 and <16, and ≥16, respectively. We compared the three groups, analyzing the associations between all variables and the locomotor function using univariate and multivariate analyses. RESULTS: Although there was no significant difference in sex ratio, BMD, ASMI, and trunk-flexor strength, significant differences were observed in age (p < 0.01), the prevalence of DLS (p = 0.02), trunk-extensor strength (p < 0.01), and trunk-extensor/flexor strength ratio (p < 0.01) among the three groups. In multiple regression analyses, the significant risk factors of the TUG test were age (ß = 0.26), body mass index (ß = 0.36), LSA (ß = 0.15), ASMI (ß = -0.30), and trunk-extensor strength (ß = -0.19), whereas the significant factor of the GLFS-25 score was trunk-extensor strength (ß = -0.31). CONCLUSIONS: The results indicate that it is clinically important for LS to pay careful attention not only to BMD but also to lumbar scoliosis when DXA examination of the lumbar spine is routinely conducted. Moreover, it is essential to note that trunk-extensor strength is more important than trunk-flexor strength in maintaining locomotor function in elderly individuals.

Predictors of walking ability after surgery for lumbar spinal canal stenosis: a prospective study.

BACKGROUND CONTEXT: Few studies have investigated predictors of objective walking distance in patients with lumbar spinal stenosis (LSS). PURPOSE: This study aimed to clarify objective predictors of postoperative 6-minute walk distance (6MWD) in patients with LSS and to develop prediction equations. STUDY DESIGN: This was a prospective study. Data were analyzed by multiple linear regression analyses. PATIENT SAMPLE: Patients with LSS were enrolled. OUTCOME MEASURES: Predictors of 6MWD after surgery were evaluated, including patient characteristics (sex, age, height, and body weight), pain (visual analog scale; low back pain, lower limb pain, and lower limb numbness), surgical factors (number of operation segments [1 or ≥2], surgery type [fusion or decompression], and minimum area of the dural sac), and objective physical function (6MWD and trunk muscle strength). METHODS: Patients with LSS were consecutively included and assessed preoperatively (n=113) and 6 months postoperatively (n=78). Simple and multiple linear regression analyses were performed with 6MWD at 6 months postoperation as the dependent variable. We have study funding sources (Nagono Medical Foundation) and no study-specific conflicts of interest-associated biases. RESULTS: At 6-month follow-up, 6MWD (457.7±105.5 m) improved significantly compared with preoperative 6MWD (275.0±157.2 m; p<.01). Trunk muscle strength and pain improved significantly compared with the preoperative score (p<.01). The predictors of postoperative 6MWD were age, body weight, number of operation segments (1 or ≥2), surgery type (fusion or decompression), preoperative trunk extensor strength, and preoperative 6MWD (adjusted R2=0.65, p<.01). The proposed prediction equation was as follows: postoperative 6MWD (m)=549.5-5.3×age (years)-1.8×body weight (kg)-68.3×surgery type (0: decompression, 1: fusion)-58.6×operation segment (0: one segment, 1: ≥2 segments)+3.5×trunk extensor strength (kg)+0.2×preoperative 6MWD (m). CONCLUSIONS: Younger age, lower body weight, one level operative segment, decompression surgery, and better preoperative scores for trunk extensor strength and 6MWD predicted better scores for 6 months postoperative 6MWD. Preoperative reduction in body weight and increase of trunk extensor strength might be associated with improved postoperative 6MWD scores.