The Application of Virtual Reality in Shoulder Surgery Rehabilitation.

To achieve a positive functional prognosis in orthopedic surgery, particularly in shoulder surgeries, effective rehabilitation is essential. Recently, there has been growing interest in the use of virtual reality (VR) in the field of orthopedics, particularly for preoperative education and training, as well as clinical and home-based rehabilitation. This report describes the process of developing an application utilizing Meta Quest 2 VR technology (Meta, CA, USA) for rehabilitation after shoulder surgery. This application assists patients in performing postoperative exercises at home by wearing VR equipment tailored to their postoperative weeks. The advantages of VR rehabilitation lie in overcoming the limitations of traditional rehabilitation methods and providing patients with a better rehabilitation experience. Moreover, automating the rehabilitation process and reducing patients' visits to clinics can lead to cost savings. This report raises expectations for the potential and scalability of VR utilization, extending beyond orthopedics to other fields. In addition, it anticipates that with better feedback and motivation, the rehabilitation effects for patients can be further enhanced.

Comparison of Fusion Rates among Various Demineralized Bone Matrices in Posterior Lumbar Interbody Fusion.

Background and Objectives: Posterior lumbar interbody fusion (PLIF) plays a crucial role in addressing various spinal disorders. The success of PLIF is contingent upon achieving bone fusion, as failure can lead to adverse clinical outcomes. Demineralized bone matrix (DBM) has emerged as a promising solution for promoting fusion due to its unique combination of osteoinductive and osteoconductive properties. This study aims to compare the effectiveness of three distinct DBMs (Exfuse®, Bongener®, and Bonfuse®) in achieving fusion rates in PLIF surgery. Materials and Methods: A retrospective review was conducted on 236 consecutive patients undergoing PLIF between September 2016 and February 2019. Patients over 50 years old with degenerative lumbar disease, receiving DBM, and following up for more than 12 months after surgery were included. Fusion was evaluated using the Bridwell grading system. Bridwell grades 1 and 2 were defined as 'fusion', while grades 3 and 4 were considered 'non-fusion.' Clinical outcomes were assessed using visual analog scale (VAS) scores for pain, the Oswestry disability index (ODI), and the European quality of life-5 (EQ-5D). Results: Fusion rates were 88.3% for Exfuse, 94.3% for Bongener, and 87.7% for Bonfuse, with no significant differences. All groups exhibited significant improvement in clinical outcomes at 12 months after surgery, but no significant differences were observed among the three groups. Conclusions: There were no significant differences in fusion rates and clinical outcomes among Exfuse, Bongener, and Bonfuse in PLIF surgery.

Comparative Study of Post-Surgical Outcomes in Pain, Disability, and Health-Related Quality of Life for Adult Spinal Deformity in Patients Aged above and below 75 Years.

(1) Background: Adult spinal deformity (ASD) surgery is known to improve clinical and radiological parameters; however, it may also cause more complications in elderly patients. The purpose of this study was to compare the outcomes of ASD surgery, specifically regarding pain, disability, and health-related quality of life (HRQOL) in patients aged 75 years and over and patients aged under 75 years; (2) Methods: A total of 151 patients who underwent ASD surgery between August 2014 and September 2020 were included. Patients were divided into two groups based on whether they are 75 years and over or under. Radiological parameters measured included sagittal vertical axis (SVA), pelvic tilt (PT), and pelvic incidence (PI)- lumbar lordosis (LL). Data were collected 3, 6, and 12 months after surgery; (3) Results: At 12 months postoperatively, visual analog scale (VAS) for low back pain (p = 0.342), Oswestry disability index (ODI) (p = 0.087), and EuroQol 5-Dimensions (EQ-5D) (p = 0.125) did not differ between patients under 75 years and those 75 and above 75 group. PT (p = 0.675), PI-LL (p = 0.948), and SVA (p = 0.108) did not differ significantly 12 months after surgery in the two groups. In the entire patient group, compared to preoperative data, significant improvements were demonstrated for clinical and radiological parameters 12 months after surgery (all p < 0.001). The rate of medical complications did not correlate with age, but the rates of proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) did (p = 0.638, p < 0.001, and p = 0.001, respectively); (4) Conclusions: In terms of clinical and radiological improvements, ASD surgery should be considered for patients regardless of whether they are younger than or older than 75 years. The clinical and radiological improvements and the risk of complications and revision surgeries must be considered in ASD patients who are 75 years or older.

Effect of surface matching mismatch of focal knee articular prosthetic on tibiofemoral contact stress using finite element analysis.

Aims: Focal knee arthroplasty is an attractive alternative to knee arthroplasty for young patients because it allows preservation of a large amount of bone for potential revisions. However, the mechanical behaviour of cartilage has not yet been investigated because it is challenging to evaluate in vivo contact areas, pressure, and deformations from metal implants. Therefore, this study aimed to determine the contact pressure in the tibiofemoral joint with a focal knee arthroplasty using a finite element model. Methods: The mechanical behaviour of the cartilage surrounding a metal implant was evaluated using finite element analysis. We modelled focal knee arthroplasty with placement flush, 0.5 mm deep, or protruding 0.5 mm with regard to the level of the surrounding cartilage. We compared contact stress and pressure for bone, implant, and cartilage under static loading conditions. Results: Contact stress on medial and lateral femoral and tibial cartilages increased and decreased, respectively, the most and the least in the protruding model compared to the intact model. The deep model exhibited the closest tibiofemoral contact stress to the intact model. In addition, the deep model demonstrated load sharing between the bone and the implant, while the protruding and flush model showed stress shielding. The data revealed that resurfacing with a focal knee arthroplasty does not cause increased contact pressure with deep implantation. However, protruding implantation leads to increased contact pressure, decreased bone stress, and biomechanical disadvantage in an in vivo application. Conclusion: These results show that it is preferable to leave an edge slightly deep rather than flush and protruding.

Translucency and masking ability of translucent zirconia; comparison with conventional zirconia and lithium disilicate.

PURPOSE: The purpose of this study is to evaluate translucency and masking ability of translucent zirconia compared to conventional zirconia and lithium disilicate materials. MATERIALS AND METHODS: Three types of zirconia blocks with different yttria contents (3Y, 4Y, 5.5Y) and LS blocks (Rosetta SM) were used. Ten specimens for each group were fabricated with 10 mm diameter, with both 0.8 mm and 1.5 mm thicknesses (± 0.02 mm). All groups of zirconia specimens were sintered and polished according to the manufacturer's instructions. To calculate the translucency parameter (TP), CIELAB value was measured with a spectrophotometer on black and white backgrounds. To investigate the color masking abilities, background shades of A2, normal dentin, discolored dentin, and titanium were used. The color difference (ΔE) was calculated with the CIELAB values of A2 shade background as a reference compared with the values in the various backgrounds. One-way ANOVA and Bonferroni tests were conducted (P < .05). RESULTS: The TP values of zirconia specimens increased as the yttria content increased. All materials used in the study were able to adequately mask normal dentin shade (ΔE < 5.5), but were incapable of masking severely discolored dentin (ΔE > 5.5). On the titanium background, all materials of 1.5 mm thickness were able to mask the background shade, but with a thickness of 0.8 mm, only 3Y-TZP and 4Y-PSZ were able to mask titanium background. CONCLUSION: All zirconia materials and lithium disilicate specimens used in this study were unable to adequately mask the shade of severely discolored dentin. It is recommended to use 3Y-TZP or 4Y-PSZ with a sufficient thickness of 0.8 mm or more to mask titanium.

Finite element analysis of femoral component sagittal alignment in mobile-bearing total knee arthroplasty.

BACKGROUND: Recently, there has been an increasing interest in mobile-bearing total knee arthroplasty (TKA). However, changes in biomechanics for femoral component alignment in mobile-bearing TKA have not been explored in depth. OBJECTIVE: This study aims to evaluate the biomechanical effect of sagittal alignment of the femoral component in mobile-bearing TKA. METHODS: We developed femoral sagittal alignment models with -3°, 0°, 3°, 5°, and 7° flexion. We also examine the kinematics of the tibiofemoral (TF) joint, contact point on the TF joint, contact stress on the patellofemoral (PF) joint, collateral ligament force, and quadriceps force using a validated computational model under a deep-knee-bend condition. RESULTS: Posterior kinematics of the TF joint increases as the femoral component flexes. The contact stress on the PF joint, collateral ligament force, and the quadriceps force decreases as the femoral component flexes. CONCLUSIONS: Our results show that a slight, approximately 0°âˆ¼3°, flexion of the implantation could be an effective substitute technique. However, excessive flexion should be avoided because of the potential loosening of the TF joint.

The posterior cortical axis as an alternative reference for femoral component placement in total knee arthroplasty.

BACKGROUND: Although several reference axes have been established for determining femoral rotational alignment during total knee arthroplasty (TKA), the most accurate axis is undetermined. This study determines the relationship between the posterior cortical axis (PCA) and the trochlear anterior line (TAL) of the femur in relation to the epicondylar axis. METHODS: A total of 341 patients who underwent TKA for osteoarthritis were enrolled. Patients who had undergone previous bony surgery or replacement that might have changed the femoral geometry were excluded. Finally, 336 patients (200 females and 136 males) were included in the study. The angles between the transepicondylar axis (TEA) and TAL and TEA and the femoral PCA (FPCA) were evaluated. We also assessed whether there was any significant differences in variance and gender in these two angles. Student's t tests were used to determine the significance of coronal alignment and any gender-based differences. The variances between the TAL/TEA and FPCA/TEA angles were compared using F tests. RESULTS: The FPCA was externally rotated by 2.6° ± 3.6°, and the trochlear anterior line was internally rotated by 5.2° ± 5.5°, relative to the TEA. Gender-based differences were observed in the comparisons between anatomical references and TEA. CONCLUSIONS: The FPCA is a more conservative landmark than the TAL for intraoperative or postoperative approximation of the TEA. When conventional reference axes, such as the posterior condylar axis and the anteroposterior axis, are inaccurate, surgeons can refer to this alternative reference. These findings demonstrate that the FPCA may be useful for determining the rotational alignment of the femoral component before and during TKA.

Effect of the presence of the articular cartilage on the femoral component rotation in total knee arthroplasty in female and varus osteoarthritis knees.

PURPOSE: Surgical techniques for total knee arthroplasty (TKA) require femoral rotational corrections that alter the position of the surface of the posterior femoral joint especially in kinematic alignment. However, preoperative planning of TKA based on computed tomography (CT), without knowing the femoral cartilage thickness, may cause post-surgery failures in femoral rotation. Therefore, this study aimed to evaluate the effects of posterior condyle cartilage thickness on rotational alignment in the femoral component. METHODS: Three-dimensional magnetic resonance imaging (MRI) scans were obtained for 139 male and 531 female osteoarthritis patients. The angles defined by the femoral posterior condylar axis (PCA) and the surgical transepicondylar axis (TEA) were evaluated with respect to the presence of cartilage. Additionally, these effects were evaluated with respect to patient gender and varus/valgus condition. RESULTS: In all patients, the angle between the TEA and PCA was significantly greater in the presence of cartilage than in the absence of cartilage. This result was also seen in female patients. However, there was no difference in the TEA/PCA angle in male patients based on the presence of cartilage. The TEA/PCA angle was significantly greater in the presence of cartilage than in the absence of cartilage in the female varus group. However, there were no differences in the TEA/PCA angle based on the presence of cartilage in the male varus/valgus and female valgus groups. Cartilage thickness in the posterior femoral condyle was significantly greater on the lateral side than on the medial side in all and male patients. However, there was no difference between the genders regarding cartilage thickness. CONCLUSION: Surgical planning for TKA based on CT does not consider articular cartilage and could lead to external malrotation of the femoral implant. Therefore, the effect of the remaining posterior condylar cartilage should be considered by surgeons to prevent over-rotation of the femoral component, especially in female varus knees.

Sleep Disturbance and Its Clinical Implication in Patients with Adult Spinal Deformity: Comparison with Lumbar Spinal Stenosis.

Purpose: The purpose of this study was to investigate the prevalence of sleep disturbance and its clinical implication in patients with ASD. Methods: A total of 44 patients with ASD and 137 patients with lumbar spinal stenosis (LSS) were enrolled in the study. Forty four patients were selected from the LSS group after propensity score matching. Global Pittsburgh Sleep Quality Index (PSQI) score, demographic data, visual analog scale (VAS) score for back and leg pain, Oswestry Disability Index (ODI), and EuroQol 5-dimension questionnaire (EQ-5D) were compared between both groups. Multiple regression analysis was performed with VAS for back pain as the dependent variable and age, sex, PSQI, and VAS for leg pain as the independent variables in the ASD group. Results: 33 (75.0%) and 32 (72.7%) patients were classified as poor sleepers in the ASD group and the LSS group, respectively. In the ASD group, the VAS score for back pain was 7.7 ± 1.7 in the poor sleeper group and 5.6 ± 2.2 in the nonpoor sleeper group. In the LSS group, poor sleep quality was associated with the ODI score, ODI score without a sleep component, and EQ-5D. The regression model for predicting VAS for back pain in the ASD group suggested that poor sleep quality and increased leg pain were associated with increased back pain. Conclusions: Because sleep quality is a critical factor in augmenting back pain in patients with ASD, this study underlines the need to investigate sleep quality during the routine examination of patients with ASD.

Gender difference in bowing of the sagittal femoral morphology measurement using magnetic resonance imaging.

The importance of femoral sagittal bowing on total knee arthroplasty (TKA) has not been actively discussed. Femoral sagittal bowing can lead to cortex damage, fractures, or femoral malalignment. Therefore, the purpose of this study was to evaluate femoral sagittal bowing at different segments of the femur in the Korean population, and to discuss the implications on total knee arthroplasty. Differences in the morphology of femoral sagittal bowing for 978 patients-829 women and 148 men-were evaluated using magnetic resonance imaging. The angle between the femoral mechanical axis and the anterior cortex line was measured for all the patients. In addition, the gender difference in femoral sagittal bowing was investigated. The angle of femoral sagittal bowing with the mechanical axis was 2.8˚ ± 2.2˚. The angles for femoral sagittal bowing were 2.9˚ ± 2.2˚ and 2.3˚ ± 2.6˚ for females and males, respectively. Thus, a gender difference was found in the femoral sagittal bowing (p < 0.05). Excessive sagittal bowing of the femur can affect the final sagittal position of the femoral component, and this has implications for implant design selection. We recommend that surgeons accurately perform pre-operative evaluation of femoral bowing to prevent potential malalignment, rotation, and abnormal stresses between the femur and implant.

Prediction of wear performance in femoral and tibial conformity in patient-specific cruciate-retaining total knee arthroplasty.

BACKGROUND: Articular surface curvature design is important in tibiofemoral kinematics and the contact mechanics of total knee arthroplasty (TKA). Thus far, the effects of articular surface curvature have not been adequately discussed with respect to conforming, nonconforming, and medial pivot designs in patient-specific TKA. Therefore, this study evaluates the underlying relationship between the articular surface curvature geometry and the wear performance in patient-specific TKA. METHODS: We compare the wear performances between conventional and patient-specific TKA under gait loading conditions using a computational simulation. Patient-specific TKAs investigated in the study are categorized into patient-specific TKA with conforming articular surfaces, medial pivot patient-specific TKA, and bio-mimetic patient-specific TKA with a patient's own tibial and femoral anatomy. The geometries of the femoral components in patient-specific TKAs are identical. RESULTS: The anterior-posterior and internal-external kinematics change with respect to different TKA designs. Moreover, the contact pressure and area did not directly affect the wear performance. In particular, conforming patient-specific TKAs exhibit the highest volumetric wear and wear rate. The volumetric wear in a conforming patient-specific TKA is 29% greater than that in a medial pivot patient-specific TKA. CONCLUSION: The findings in this study highlight that conformity changes in the femoral and tibial inserts influence the wear performance in patient-specific TKA. Kinematics and contact parameters should be considered to improve wear performance in patient-specific TKA. The conformity modification in the tibiofemoral joint changes the kinematics and contact parameters, and this affects wear performance.

Biomechanical effects of posterior tibial slope on unicompartmental knee arthroplasty using finite element analysis.

BACKGROUND: The effects of the posterior slope of the tibial prosthesis on unicompartmental knee arthroplasty have not been fully evaluated and controversies still exist. OBJECTIVE: This study evaluates the effects of the posterior slope of the tibia on contact stresses in polyethylene inserts and articular cartilage using finite element analysis. METHODS: We generated a computational model followed by the development of a posterior tibial slope (PTS) from -1° to 15° cases with increments of 2° PTS models. Using a validated finite element (FE) model, we investigated the influence of the changes in PTS on the contact stress in the medial polyethylene insert and lateral cartilage. The FE model's loading condition is level walking, a normal daily activity. RESULTS: The contact stress increased on the lateral articular cartilage as the PTS increased. The contact stress on the polyethylene insert differed from the contact stress on the lateral articular cartilage, and it generally increased as the PTS decreased. However, in the initial stance phase when an axial force was exerted, it increased as the PTS increased. CONCLUSIONS: Our results show that an offset of ±2° from the initial anatomical tibial slope does not biomechanically affect the outcome.

Biomechanical effect with respect to the sagittal positioning of the femoral component in unicompartmental knee arthroplasty.

BACKGROUND: Component malalignment in unicompartmental knee arthroplasty (UKA) has been related to the concentration in tibiofemoral joint of contact stress and to poor post-operative outcomes. Few studies investigated a biomechanical effect of femur component position in sagittal plane. The purpose of this study was to evaluate the biomechanical effect of the femoral components on the sagittal alignment under flexion and extension conditions using computational simulations. METHODS: The flexion and extension conditions of the femoral component were analyzed from 10° extension to 10° flexion in 1° increments. We considered the contact stresses in the polyethylene (PE) inserts and articular cartilage, and the force on the collateral ligament, under gait cycle conditions. RESULTS: The contact stress on the PE insert increased as flexion of the femoral component increased, but there was not a remarkable difference in the amount of increased contact stress upon extension. There was no difference in the contact stress on the articular cartilage upon extension of the femoral component, but it increased in flexion during stance and double support periods. The forces on the medial collateral ligaments increased with the extension and decreased with the flexion of the femoral component, whereas the forces on the lateral collateral ligaments showed opposite trends. CONCLUSIONS: Surgeons should be concerned with femoral component position on UKA not only in frontal plane but also in the sagittal plane, because flexion or extension of the femoral component may impact the PE or opposite compartment along with the surrounding ligaments around knee joint.

Incidence and Risk Factors of Postoperative Hematoma Requiring Reoperation in Single-level Lumbar Fusion Surgery.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: The purpose of the present study was to examine the incidence and risk factors for postoperative hematoma requiring reoperation in patients undergoing single-level lumbar fusion surgery. SUMMARY OF BACKGROUND DATA: Postoperative hematoma can cause devastating neurological consequences after spine surgery. Risk factors for hematoma in specific spine procedures have not been well established. METHODS: A cohort of patients undergoing single-level lumbar fusion surgery was constructed from the 2012 to 2013 American College of Surgeons National Surgical Quality Improvement Program dataset using Current Procedural Terminology codes (22533, 22558, 22612, 22630, and 22633). In cases requiring reoperation within 30 days after initial surgery, postoperative hematoma was identified using the ICD-9 code 998.1. Risk factors for postoperative hematoma were assessed with logistic regression modeling. RESULTS: Of 5280 patients undergoing single-level lumbar fusion surgery, 27 patients (0.5%) developed a postoperative hematoma requiring reoperation for hematoma evacuation. A heightened incidence of postoperative hematoma was found in patients who were smokers (1.0% vs. 0.4% for nonsmokers, P = 0.016) or who had a diagnosis of bleeding disorder (3.8% vs. 0.5% for those without bleeding disorder, P = 0.007). Multivariate logistic regression analysis indicated that the adjusted odds ratios for postoperative hematoma associated with smoking and bleeding disorder were 3.34 (95% confidence interval, 1.15-9.71) and 10.2 (95% confidence interval, 1.9-54.8), respectively. CONCLUSION: Smoking and bleeding disorder appear to be major risk factors for postoperative hematoma requiring reoperation after single-level lumbar fusion surgery. Intervention programs targeting patients with these risk factors are needed to reduce their excess risk of postoperative hematoma. LEVEL OF EVIDENCE: 3.

Validation of the Korean Version of the DN4 Diagnostic Questionnaire for Neuropathic Pain in Patients with Lumbar or Lumbar-Radicular Pain.

PURPOSE: To evaluate the diagnostic value of the Korean version of the Douleur Neuropathique 4 (DN4) questionnaire and to validate this questionnaire in terms of psychometric properties in patients with chronic pain due to degenerative spinal disease. MATERIALS AND METHODS: The Korean version of the DN4 questionnaire, which was translated and linguistically validated by the MAPI Research Group, was tested on 83 patients with lumbar or lumbar-radicular pain. Test-retest reliability was evaluated in a subsample of 40 patients who completed two assessments with an interval of 2 weeks. Nociceptive pain and neuropathic component pain were diagnosed in 40 and 43 patients, respectively. RESULTS: The Cronbach's α coefficient of internal consistency was 0.819, and the test-retest intraclass correlation coefficient (3, 1) (95% confidence interval) was 0.813 (0.776-0.847) (n=40). The area under the receiver-operator characteristics curve was 0.953 (p<0.001), with 95% confidence interval between 0.869 and 0.990. The Korean version of the DN4 questionnaire showed a sensitivity of 100% and 87.1%, and a specificity of 88.2% and 94.1% at the cutoff value of 3/10 and 4/10, respectively, for discriminating neuropathic component pain. CONCLUSION: The present study demonstrated the good discriminatory power of DN4 between nociceptive pain and neuropathic component pain in patients with lumbar or lumbar-radicular pain.

Prediction of postoperative pain intensity after lumbar spinal surgery using pain sensitivity and preoperative back pain severity.

OBJECTIVES: To investigate the role of preoperative pain sensitivity and preoperative symptom severity for prediction of postoperative pain intensity after lumbar spine surgery. METHODS: This study consisted of two groups who underwent decompression surgery alone (62 patients) or decompression with fusion surgery (37 patients) for lumbar spinal stenosis (LSS). Pain Sensitivity Questionnaire (PSQ) and visual analog pain scale (VAS) for back pain and leg pain were collected preoperatively with detailed medical history. The assessment was performed immediately after surgery when the patients had completely recovered and regained their complete consciousness from general anesthesia (H0) and subsequently 4, 8, 18, 30, 48, and 72 hours (H4, H8, H18, H30, H48, and H72) thereafter as they recovered. RESULTS: Both groups showed a decrease in back pain and leg pain with the time postoperatively. In fusion group, preoperative VAS for back pain was significantly correlated with postoperative VAS for back pain at H0, H4, H8, and H18, and PSQ minor/total PSQ also showed a significant correlation with postoperative back pain at H48 and H72. In contrast, only total PSQ and PSQ minors were significantly correlated with postoperative back pain at H18 and H30 in decompression group. Hierarchical regression analysis finally showed that each preoperative back pain and PSQ minor was predictive of immediate postoperative back pain (from H0 to H18) in fusion group and delayed postoperative back pain (H18, H30) in decompression group. CONCLUSIONS: The study highlights that each preoperative back pain and individual pain sensitivity could predict the different aspects of postoperative pain after lumbar surgery.

Effects of single or repeated silymarin administration on pharmacokinetics of risperidone and its major metabolite, 9-hydroxyrisperidone in rats.

1. The interactions between herbal dietary supplements and therapeutic drugs have emerged as an important issue and P-glycoprotein (P-gp) has been reported as one of the significant factors of these interactions. 2. The objective of this article is to examine the effects of single and repeated administrations of silymarin on pharmacokinetics of a P-gp substrate, risperidone, and its major metabolite, 9-hydroxyrisperidone, in rats. 3. To determine the plasma levels of risperidone and 9-hydroxyrisperidone in rats, a HPLC method was developed using a liquid-liquid acid back extraction. When risperidone (6 mg/kg) was co-administered with silymarin (40 mg/kg) to rats orally, the C(max) of 9-hydroxyrisperidone was significantly increased to1.3-fold (p < 0.05), while the other pharmacokinetic parameters did not show any significant differences. Expanding the experiment where rats were repeatedly administered with silymarin for 5 days prior to giving risperidone, the C(max) of risperidone and 9-hydroxyrisperidone were significantly increased to 2.4-fold (p < 0.001) and 1.7-fold (p < 0.001), respectively, and the AUC(0-t), as well to 1.7-fold (p < 0.05) and 2.1-fold (p < 0.01), respectively. 4. The repeated exposures of silymarin, compared to single administration of silymarin, increased oral bioavailability and affected the pharmacokinetics of risperidone and 9-hydroxyrisperidone, by inhibiting P-gp.

The efficacy of transforaminal epidural steroid injection by the conventional technique in far-lateral herniation of lumbar disc.

BACKGROUND: Owing to the anatomical difference between the far lateral herniation of the lumbar disc (FHLD) and the intraspinal herniation of lumbar disc (iHLD), the outcome of transforaminal epidural steroid injections (TFESI) in patients with FHLD seems to be different from that in patients with iHLD. However, few studies have evaluated the efficacy of TFESI in FHLD. OBJECTIVE: To evaluate and compare the efficacy of TFESI in FHLD and iHLD patients. STUDY DESIGN: A retrospective design. METHODS: There were 15 and 70 patients in the FHLD and iHLD groups, respectively. Patients received a fluoroscopically guided TFESI. Failure rates of TFESI were recorded, and questionnaires, including a visual analog scale (VAS) for leg pain and Oswestry disability index (ODI) were administered before the initial injection, at 2 weeks, 6 weeks, and 12 weeks after the injections. RESULTS: There was no failure for TFESI in the iHLD group, while 9 patients had to undergo alternative blocks in the FHLD group due to lancinating leg pain when the needle was advanced for TFESI. In the iHLD group, there was a statistically significant improvement in the VAS and ODI score 12 weeks after injection. Considering only successful cases of the FHLD group, significant improvement in the VAS and ODI score was also demonstrated in the FHLD group 12 weeks after injection. Moreover, there was no statistically significant difference of the VAS and ODI between the both groups. LIMITATIONS: A relatively small numbers of cases were included in the FHLD group. CONCLUSION: The current study suggests that an alternative needle placement technique for TFESI appears to be necessary for FHLD patients.

Effects of silymarin and formulation on the oral bioavailability of paclitaxel in rats.

The aims of the present study were to investigate the effects of silymarin, an inhibitor of the P-glycoprotein efflux pump, on oral bioavailability of paclitaxel in rats, and to compare pharmacokinetic parameters of paclitaxel between a commercial formulation of paclitaxel (Taxol®) and a paclitaxel microemulsion. Oral bioavailability of paclitaxel in a Taxol® formulation was enhanced in the combination with silymarin (10 and 20mg/kg). In particular, the mean maximum plasma concentration (C(max)) and the mean area under the plasma concentration-time curve (AUC(0-)(t)) of paclitaxel in the Taxol® formulation were significantly increased 3-fold and 5-fold compared with control, respectively, following oral co-administration with 10mg/kg of silymarin (p<0.01). When the paclitaxel microemulsion was co-administered with silymarin (20mg/kg) orally, it caused a maximum increase in the absolute bioavailability of paclitaxel (19%). In addition, the relative bioavailability of the paclitaxel microemulsion was 184% as compared to Taxol® after oral dosing, whereas the mean time required to reach C(max) (T(max)) of paclitaxel was decreased in the microemulsion formulation compared with Taxol®, suggesting faster absorption. Based on these results, we conclude that oral bioavailability of paclitaxel is significantly improved by co-administration with silymarin, an inhibitor of the P-gp efflux pump and by microemulsion formulation.