Does Revision Anterior Cruciate Ligament (ACL) Reconstruction Provide Similar Clinical Outcomes to Primary ACL Reconstruction? A Systematic Review and Meta-Analysis.

More revisionary reconstruction procedures are required following failing anterior cruciate ligament (ACL) reconstructions, which are often regarded as a technique challenge with very limited goals. This study will be performed to compare the outcomes between groups of primary and revision knee reconstruction. Two observers conducted the literature retrieval from the platforms of PubMed, Embase, and CENTRAL. Studies which compared knee function and stability between primary and revisionary reconstructions were included. The data was synthesized by meta-analysis with fixed- or random-effects models as appropriate. A total of 10 eligible studies were included with 954 subjects in the primary group and 378 in the revision group. The International Knee Documentation Committee International Knee Documentation Committee (IKDC) subscores, side-to-side difference, and Lysholm score were demonstrated to be significantly improved at final follow-up in both groups, while Tegner score was not. The overall IKDC, Knee injury and Osteoarthritis Outcome Score (KOOS), and Lysholm scores were significantly inferior in the revision group compared to the primary group. However, knee laxity according to side-to-side difference was demonstrated to be similar between the two groups. Revision ACL reconstruction (RACLR) could provide patients with excellent restoration of knee outcomes compared to the status before revision. Also, while knee function in the revision group was inferior to the primary group, knee stability was equivalent between the two groups at the final follow-up.

Clinical Outcomes of the Central Third Patellar Tendon Versus Four-strand Hamstring Tendon Autograft Used for Anterior Cruciate Ligament Reconstruction: A Systematic Review and Subgroup Meta-analysis of Randomized Controlled Trials.

BACKGROUND: The most frequently used auto-grafts for ACL reconstruction (ACLR) are bone-patellar tendon-bone (BPTB) and four-strand hamstring tendon (4S-HT), but significant controversy exists about which graft is better. This study aimed to compare the knee outcomes following ACLR with BPTB and 4S-HT autografts. METHODS: Subgroup meta-analyses were performed basing on available randomised controlled trials (RCTs) according to different follow-up intervals. 23 RCTs were eligible for inclusion, involving 933 participants in each treatment group. RESULTS: Only short-term (≤2 years) knee anteroposterior and rotational stability were significantly poorer with 4S-HT when compared to BPTB autograft, as judged by side-to-side difference on knee laxity (WMD=-0.50, 95%CI -0.81~-0.18, p=0.002) and pivot-shift test (OR=0.58, 95%CI 0.39~0.88, p=0.010), respectively. The IKDC objective grade was evident to be in favour of 4S-HT group in mid-term (3-5 years) follow-up (OR=0.63, 95%CI 0.43~0.92, p=0.017). Several donor-site related complications, including anterior knee pain, pain with kneeling and extension deficit, were more frequent in BPTB autograft group, while lower short-term iskinetic peak flexion torques both at 60°/S (WMD=8.93, 95%CI 7.88~9.99, p<0.001) and 240°/S (WMD=11.63, 95%CI 9.92~13.34, p<0.001) were caused by HT harvesting. CONCLUSION: BPTB was associated with inferior mid- to long-term (>5 years) knee functional outcomes, and increased frequency of donor-site complications. In contrast, only short-term knee laxity was increased for 4S-HT autograft, which is expected to be improved by providing more conservative rehabilitation protocol and aperture fixation methods.

Visceral Metastasis: A Prognostic Factor of Survival in Patients with Spinal Metastases.

OBJECTIVE: To characterize the visceral metastasis as a predictive tool for the survival of patients with spinal metastases through an exploratory meta-analysis. METHODS: Two investigators independently searched PubMed and Embase databases for eligible studies from 2000-2016. The effect estimates for the hazard ratio (HR) or risk ratio (RR) and 95% confidence interval (CI) were collected and pooled with a random- or fixed-effect model. RESULTS: In total, 18 eligible studies were retrieved with 5468 participants from nine countries. The overall pooled effect size for HR and RR was 1.50 and 3.79, respectively, which was proved to be statistically significant. In the subgroup of prostate cancer (PCa) and non-small cell lung cancer (NSCLC), statistical significance and marginal statistical significance was presented for the pooled HR (HR = 1.76, 95% CI 1.35-2.29) and (RR = 1.56, 95% CI 0.99-2.48), respectively. However, in the subgroup of thyroid cancer, breast cancer, and renal cancer, statistical significance was not achieved (HR = 1.17, 95% CI 0.75-1.83, Z = 0.70, P = 0.486). The results did not show any evidence of publication bias. CONCLUSIONS: This study demonstrated that visceral metastasis was a significant prognostic factor in patients with spinal metastases as a whole. Interestingly, the onset of visceral metastases differentially impacted the survival in different primary tumors. Therefore, the prognostic value of visceral metastasis might be related to the type of primary tumor.

Assessment of the Defatting Efficacy of Mechanical and Chemical Treatment for Allograft Cancellous Bone and Its Effects on Biomechanics Properties of Bone.

OBJECTIVE: To assess the defatting efficacy of high pressure washing and gradient alcohol and biomechanical properties of defatted bone. METHODS: Fresh cancellous bone was obtained from the femoral condyle and divided into six groups according to different defatting treatments, which were: high pressure washing for 10 s (10S group), 20 s (20S group), and 30 s (30S group), gradient alcohol immersion (Alcohol group), acetone immersion (Acetone group), and non-defatted (Fresh group). The appearance of six groups was observed, and the appearance of defatted bone and fresh bone was compared. The residual lipid content and infrared spectrum were used to compare the efficacy of defatting, the DNA content was used to compare the cell content after defatting, and the maximum stress and elastic modulus were used to compare the effects of defatting treatment on biomechanical properties. RESULTS: The fresh bone was yellow and the pores contained a lot of fat. The defatted bone was white and the porous network was clear. There was no difference in residual lipid content among the three groups with high pressure washing (1.45% ± 0.16%, 1.40% ± 0.13%, and 1.46% ± 0.11%, respectively) (P = 0.828). There was no difference in residual lipid content among the 10S, alcohol, and acetone groups (1.45% ± 0.16%, 1.28% ± 0.07%, and 1.13% ± 0.22%, respectively) (P = 0.125). Infrared spectra showed that the fat content of the five defatting groups was significantly lower than that of the fresh group. There was no difference in residual lipid content among the three groups with high pressure washing (4.53 ± 0.23 ug/mL, 4.61 ± 0.18 ug/mL, and 4.66 ± 0.25 ug/mL, respectively) (P = 0.645). There was no difference in residual lipid content among the 10S, alcohol, and acetone groups (4.53 ± 0.23 ug/mL, 4.29 ± 0.24 ug/mL, and 4.27 ± 0.29 ug/mL, respectively) (P = 0.247). The maximum stress of the bone decreased significantly with the increase of the washing time (9.95 ± 0.31 Mpa, 9.07 ± 0.45 Mpa, and 8.17 ± 0.35 Mpa, respectively) (P = 0.003). The elastic modulus of the bone decreased significantly with the increase of the washing time (116.40 ± 3.54 Mpa, 106.10 ± 5.29 Mpa, and 95.63 ± 4.08 Mpa, respectively) (P = 0.003). There was no statistical difference in the maximum stress between the fresh group, the 10S group, the alcohol group, and the acetone group (10.09 ± 0.67 Mpa, 9.95 ± 0.31 Mpa, 10.11 ± 0.07 Mpa, and 10.09 ± 0.39 Mpa, respectively) (P = 0.963). There was no statistical difference in the maximum stress between the fresh group, the 10S group, the alcohol group and the acetone group (119.93 ± 4.94 Mpa, 116.40 ± 3.54 Mpa, 118.27 ± 0.85 Mpa, 118.10 ± 4.52 Mpa, respectively) (P = 0.737). CONCLUSION: The defatting efficiency was satisfactory at a time of 10 s under high pressure washing. In terms of defatting efficiency and its effect on biomechanical properties of bone, high pressure washing and gradient alcohol were similar to conventional acetone solvent extraction defatting.

Efficacy and safety of bone substitutes in lumbar spinal fusion: a systematic review and network meta-analysis of randomized controlled trials.

PURPOSE: A variety of alternative grafts to autologous iliac crest bone (ICBG) have been developed for lumbar spondylodesis, due to frequent complications following ICBG harvest. The optimal alternative graft to ICBG, however, remains elusive till now. The purpose of this study was to compare the efficacy and safety of fusion materials in lumbar degeneration diseases and to provide a ranking spectrum of the grafts. METHODS: Randomized controlled trials (RCTs) comparing different bone grafts in lumbar arthrodesis were eligible for inclusion. A network meta-analysis was performed for endpoints including fusion rate and incidence of adverse events. RESULTS: Twenty-seven RCTs involving 2488 patients and 13 available interventions were included. rhBMP-2 provided the highest fusion rate, being significantly superior to that of ICBG (OR = 0.21, p < 0.001), autograft local bone (ALB) (OR = 0.18, p = 0.022), rhBMP-7 (OR = 0.15, p < 0.001), allograft (OR = 0.13, p = 0.009), and DBM + ALB (OR = 0.07, p = 0.048). The treatment efficacy of allograft could be significantly enhanced by bone marrow concentrate (BMC) supplying (OR = 0.16, p = 0.010). ICBG ranks second on the frequency of complications, which is significantly higher than that of allograft (OR = 0.14, p = 0.041) and ALB (OR = 0.14, p = 0.030). All of the other comparisons showed similar efficacy and safety profiles between groups. CONCLUSION: Ranking spectrums of the efficacy and safety for various bone grafts were provided graphically. Though rhBMP-2 was of the highest success rate, the application should be taken with proper caution because of the widely proposed life-threatening adverse events. ALB, ALB plus synthetic ceramic materials and allograft mixed with BMC were also proved to be potentially effective alternative graft to ICBG. These slides can be retrieved under Electronic Supplementary Material.

Network meta-analysis of knee outcomes following anterior cruciate ligament reconstruction with various types of tendon grafts.

PURPOSE: Various grafts were selected for restoring knee stability and regaining pre-injury activity levels after anterior cruciate ligament (ACL) rupture. This review aimed to compare the short-term knee outcomes of different tendon grafts for primary ACL reconstruction (ACLR). METHODS: Databases of PubMed, Embase, and CENTRAL were retrieved for identifying the published RCT comparing the short-term (≤ 2 years) knee outcomes of different tendon grafts for ACLR. The main outcomes include the International Knee Documentation Committee (IKDC) subjective and objective scores, side-to-side difference on knee laxity, Lachman test, pivot-shift test, Lysholm score, Tegner score, all recorded complications and graft re-ruptures. RESULTS: A total of 32 trials involving 2962 patients and 17 grafts were included. Superior IKDC subjective score was found for quadriceps tendon autograft (QTB) when compared with autografts including bone-patellar tendon-bone (BPTB), four-strand hamstring tendon (4S-HT), and double-bundle HT. The 4S-HT autograft was associated with poorer anteroposterior and rotational knee stability than the BPTB autograft. Artificial ligament also was found to provide lower knee stability compared with the autografts including the BPTB, patellar tendon, 4S-HT, 4S-HT with preserved tibial insertion, 6S-HT, and four-strand semitendinosus tendon. Additionally, the BPTB allograft showed a statistically higher knee laxity than 6S-HT allograft, while no difference was found between the genuine autografts and non-irradiated allografts. CONCLUSIONS: QTB was recommended to be used even over the BPTB and 4S-HT autografts. BPTB autograft was more effective on restoring the knee stability than 4S-HT autograft. Non-irradiated allografts could be safely used as alternatives to autografts. However, artificial ligaments were not recommended for primary ACLR for significantly increased risk of knee laxity.

Demineralized Bone Matrix Carriers and their Clinical Applications: An Overview.

Reconstruction of massive bone defects is challenging for orthopaedic clinicians, especially in cases of severe trauma and resection of tumors in various locales. Autologous iliac crest bone graft (ICBG) is the "gold standard" for bone grafting. However, the limited availability and complications at donor sites resulted in seeking other options like allografts and bone graft substitutes. Demineralized bone matrix (DBM) is a form of allograft using acidic solution to remove mineral components, while leaving much of the proteinaceous components native to bone, with small amounts of calcium-based solids, inorganic phosphates, and some trace cell debris. It is an osteoconductive and osteoinductive biomaterial and is approved as a medical device for use in bone defects and spinal fusion. To pack consistently into the defect sites and stay firmly in the filling parts, DBM products have various forms combined with biocompatible viscous carriers, including sponges, strips, injectable putty, paste, and paste infused with chips. The present review aims to summarize the properties of various kind of viscous carriers and their clinical use combined with DBM in commercially available products. Given DBM'mercially available products. Given DBM;s long clinical track record and commercial accessibility in standard forms, opportunities to further develop and validate DBM as a versatile bone biomaterial in orthopaedic repair and regenerative medicine contexts are attractive.

The efficacy and safety of core decompression for the treatment of femoral head necrosis: a systematic review and meta-analysis.

BACKGROUND: Core decompression (CD) is an important method for the treatment of osteonecrosis of the femoral head (ONFH). Few articles investigate the influence of core decompression on outcomes of ONFH. This study was carried out to observe the safety and effectiveness of core decompression in the treatment of ONFH. METHODS: A comprehensive literature search of databases including PubMed, Embase, and Cochrane Library was performed to collect the related studies. The medical subject headings used were "femur head necrosis" and "Core decompression." The relevant words in title or abstract included but not limited to "Osteonecrosis of the Femoral Head," "femoral head necrosis," "avascular necrosis of femoral head," and "ischemic necrosis of femoral head." The methodological index for nonrandomized studies was adopted for assessing the studies included in this review. RESULTS: Thirty-two studies included 1865 patients (2441 hips). Twenty-one studies (1301 hips) using Ficat staging standard, 7 studies (338hips) using Association Research Circulation Osseous (ARCO) staging standard, and University of Pennsylvania system for staging avascular necrosis (UPSS) staging criteria for 4 studies (802 hips). All the studies recorded the treatment, 22 studies (1379 hips) were treated with core decompression (CD) alone, and 7 studies (565 hips) were treated with core decompression combined with autologous bone (CD Autologous bone). Nine subjects (497 hips) were treated with core decompression combined with autologous bone marrow (CD Marrow). Twenty-seven studies (2120 hips) documented the number of conversion to total hip replacement (THA), and 26 studies (1752hips) documented the number of radiographic progression (RP). Twenty-one studies recorded the types of complications and the number of cases, a total of 69 cases. The random-effect model was used for meta-analysis, and the results showed that the overall success rate was 65%. The rate of success showed significant difference on the outcomes of different stages. The rate of success, conversion to THA, and radiographic progression showed significant difference on the outcomes of ONFH using different treatments. CONCLUSIONS: Core decompression is an effective and safe method of treating ONFH. The combined use of autologous bone or bone marrow can increase the success rate. For advanced femoral head necrosis, the use of CD should be cautious. High-quality randomized controlled trials and prospective studies will be necessary to clarify the effects of different etiology factors, treatments, and postoperative rehabilitation. Until then, the surgeon can choose core decompression to treat ONFH depending on the patient's condition. LEVEL OF EVIDENCE: I Meta-analysis.

Development and validation of a prognostic nomogram for the overall survival of patients living with spinal metastases.

INTRODUCTION: The primary goal of treatment in spinal metastasis is typically to extend patients' lifespan as much as possible, and optimally to relieve the symptoms and so improve quality of life. It is crucial to avoid over- or under-treatment, according to each patient's individual situation. Thus, this study aimed to identify significant prognostic factors for patients living with metastatic spine disease, and create a new nomogram for the prediction of survival rates. METHODS: Data from patients who had undergone operations for spinal metastasis between 2005 and 2016 were retrieved retrospectively, and randomized into training (70%) and validation groups (30%). A selection of pre-operative factors was analyzed using univariable and multivariable COX model for the training group. A nomogram was then developed using significant predictors in multivariable analysis. Accuracy was validated using a concordance index (C-index) and calibration curve for the training and validation groups, respectively. RESULTS: A total of 244 participants were enrolled, including 171 in the training group and 73 in the validation group. Primary tumor, Frankel Grade, Karnofsky Performance Score (KPS) and adjuvant therapy were found to be significant for predicting survival rates. A nomogram was developed by utilizing these predictors. The C-indexes for the two groups were 0.711 and 0.703 respectively. Moreover, a favorable consistency between the predicted and actual survival probabilities was demonstrated using calibration curves. CONCLUSIONS: A user-friendly nomogram model for facilitating medical procedures during clinical encounters was established to aid clinical decision making for individual patients.

The effect of knee bracing on the knee function and stability following anterior cruciate ligament reconstruction: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Knee brace has been commonly used as a device to protect the graft after reconstruction of anterior cruciate ligament (ACL). Studies have focused on the effects of braces after ACL reconstruction, and controversial results were reported. The current meta-analysis was conducted to identify whether knee braces could provide superior clinical outcomes on knee functional scores and stability evaluations. HYPOTHESIS: Knee braces could not provide superior clinical outcomes on knee functional scores and stability evaluations. MATERIALS AND METHODS: Two reviewers independently retrieved the literature on PubMed, Embase and the Cochrane Central Register of Controlled Trials (CENTRAL). Data related to the knee functional scores and stability evaluations, including International Knee Documentation Committee (IKDC) evaluation, Lachman test, manual anterior drawer test, single leg hop test, pivot shift test, side-to-side difference, Lysholm score and Tegner score, were extracted and pooled using meta-analysis with fixed or random- effect models when applicable. RESULTS: A total of 7 studies with 440 participants were finally included. The IKDC objective score was pooled using the odds ratio (OR) as effect size, which was demonstrated to be non-significantly different between the brace and no brace groups. All of the other clinical outcomes, including Lysholm score, Tegner score, side-to-side difference, single-leg hop test and VAS pain score, were pooled using the standard mean difference (SMD) as effect size. At final follow up, the aforementioned clinical outcomes were demonstrated to be similar between the brace and non-brace groups. DISCUSSION: Knee bracing does not appear to improve the clinical outcomes on the function and stability for ACL-reconstructed knees. Thus, bracing for patients treated with ACL reconstruction should not be recommended routinely. LEVEL OF EVIDENCE: I, Meta-analysis.

Recursive Partitioning Analysis (RPA) of Prognostic Factors for Overall Survival in Patients with Spinal Metastasis: A New System for Stratified Treatment.

BACKGROUND: Accurate survival estimate is necessary when determining the most appropriate treatment modality for metastatic spinal tumor. The main purpose of this study was to identify the prognostic factors of spinal metastasis and establish a decision tree model. METHODS: A consecutive cohort of 507 patients from 3 institutional clinical centers who were treated for metastatic spinal tumor between 2005 and 2015 were retrospectively reviewed. In total, 70% of the participants were randomly selected as a "training sample." The prognostic effect of preoperative factors was evaluated using the "training sample," and a decision tree model was established. Then, the accuracy of the new model, as well as the Tokuhashi and Tomita score, was tested by the "test sample," which consisted of the remaining 30% of participants. RESULTS: A decision tree model was generated based on the significant factors with an order of descending importance on predicting the prognosis. According to the new model, patients were classified into 3 groups, mean survival times of less than 6 months, 6-12 months, and more than 12 months, who were indicated for conservative therapy/palliative operation, palliative operation, and invasive excision, respectively. The newly established model was confirmed to be of high accuracy in predicting overall survival, whereas the Tokuhashi and Tomita scores were of modest accuracy and consistency. CONCLUSIONS: A new decision tree model for prognosis prediction in spinal metastasis was established with a satisfactory accuracy and consistency. However, the Tokuhashi and Tomita systems were presented to be less correlated between the scores and actual survival.

Prognostic Discrepancy on Overall Survival Between Ambulatory and Nonambulatory Patients with Metastatic Spinal Cord Compression.

BACKGROUND: Contradictory results have been reported regarding the prognostic effect of ambulatory status in patients with metastatic spinal cord compression (MSCC). The aim of this study was to investigate whether ambulatory status is a significant predictor of overall survival in patients with MSCC and to distinguish the differences of predictors between patients who were ambulatory and those who were not ambulatory before operation. METHODS: Three clinical centers were retrospectively reviewed to identify patients operated on for MSCC between 2005 and 2015. Fourteen prognostic factors were analyzed using Kaplan-Meier survival curves, univariate log-rank test, and multivariate Cox hazard regression model for the whole cohort and the subgroups of ambulatory and nonambulatory patients. RESULTS: In all, 169 patients were consecutively enrolled. Their mean age was 59.6 ± 10.5 years (range, 18-84 years). The median survival time in the whole cohort was 7.0 ± 0.5 months, whereas it was 7.0 ± 0.8 months and 5.0 ± 1.3 months in ambulatory and nonambulatory patients, respectively. Multivariate Cox regression analysis showed that ambulatory status was not a significant predictor of overall survival (P = 0.266), but primary tumor type and Karnofsky performance status were independent predictors of overall survival for the whole cohort. Primary tumor and metastatic site were significantly associated with survival in ambulatory patients. Gender and Karnofsky performance status were associated with survival in nonambulatory patients. CONCLUSIONS: Ambulatory status was not shown to predict the prognosis of patients with MSCC. prognostic factors should be distinguished between ambulatory and nonambulatory patients when choosing a therapeutic modality.

Prognostic effect of factors involved in revised Tokuhashi score system for patients with spinal metastases: a systematic review and Meta-analysis.

BACKGROUND: Cancer patients' survival time has obviously improved, with the development of systemic treatment techniques. However, the probability of metastases to the vertebrae has also been increased which makes some adverse effects on patients' quality of life. The prediction of survival plays a key role in choosing therapeutic modality, and Tokuhashi Score was established as one of the most commonly used predictive systems for spinal metastases. Thus, this study was conducted to identify the prognostic effect of factors involved in revised Tokuhashi Score (RTS). METHODS: Two investigators independently retrieved relevant literature on platforms of PubMed, Embase and Cochrane Library. We identified eligible studies through title/abstract and full-text perusing. Data was extracted including general information of studies, participants' characteristics, therapeutic modality, overall survival and prognostic effect of factors. Hazard ratio (HR) for each factor was synthesized if available through fixed- or random-effect models as appropriate. RESULTS: A total of 63 eligible studies with 10,411 participants were identified. Overall, cases with thyroid cancer had the highest survival rate, while the ones with non-small cell lung cancer and hepatocellular carcinoma lived for the shorted survival time. Performance status, bone metastasis, number of involved vertebrae, visceral metastasis, primary tumor and neurological status were regarded as significant predictors in 71.4, 40.0, 18.2, 63.4, 73.1 and 44.7% of the involved studies respectively. Thirty-eight articles were included in meta-analysis, and prognostic effects of five factors (apart from primary tumor) were analyzed. Factors were all proved to be significant except comparisons between KPS (Karnofsky Performance Status) 10-40 VS. 50-70 and single VS. multiple spinal metastases. CONCLUSION: All factors of RTS were significant on prognosis predicting and should be considered when choosing therapeutic modality for spinal metastases. What's more, we believe that more accurate prognosis may be obtained after removal of the cut-offs for KPS 10-40 VS. 50-70 and single VS. multiple involved vertebrae.

Is Ambulatory Status a Prognostic Factor of Survival in Patients with Spinal Metastases? An Exploratory Meta-analysis.

This study was conducted to identify the influence of ambulatory status prior to treatment on survival of patients with spinal metastases. Two investigators independently retrieved relevant electronic literature in PubMed, Embase, and Cochrane Library databases, to identify eligible studies. Effect estimates for hazard risk (HR) were extracted and synthesized through fixed-effects or random-effects models as appropriate. A total of 17 eligible studies were identified, with an accumulated number of 3962 participants. HR from 14 studies regarding comparison between ambulatory versus non-ambulatory groups were pooled using a random-effects model, and statistical significance was presented for the pooled HR (HR = 1.96; 95% confidence interval [CI], 1.65-2.34). In subgroups of mixed primary tumor and lung cancer, ambulatory status was considered to be a significant prognostic factor (P < 0.05), while in the subgroup of prostate cancer it was not (HR = 1.72; 95% CI, 0.79-3.74). HR from 4 studies related to comparison between Frankel E versus Frankel C-D were pooled using a fixed-effects model, which revealed statistical significance (HR = 1.73; 95% CI, 1.27-2.36). Ambulatory status is a significant prognostic factor in patients with spinal metastases. However, in patients with primary prostate cancer, the prognostic effect of ambulatory status has not yet been confirmed to be significant.

Prognostic Factors of Ambulatory Status for Patients with Metastatic Spinal Cord Compression: A Systematic Review and Meta-Analysis.

BACKGROUND: This study aimed to identify prognostic factors for functional outcome of metastatic spinal cord compression (MSCC). METHODS: All full texts in English regarding the prognostic factors for functional outcome of MSCC, published between January 2007 and October 2017, were identified using the electronic databases PubMed, Embase, and the Cochrane Library. An exploratory meta-analysis was also conducted when appropriate data were available. RESULTS: A total of 25 studies, involving 4897 patients, met the inclusion criteria. Overall, 69.7% of patients across all studies were able to walk postoperatively compared with 49.0% preoperatively. Moreover, 84.7% of the patients maintained ambulation after treatment. Motor function was significantly associated with ambulatory status before treatment, time of developing motor deficits, interval from symptom to surgery, and preoperative performance status. CONCLUSIONS: Ambulatory status before treatment, interval from symptom to treatment, and time of developing motor deficits can be considered as the most significant prognostic factors for posttreatment ambulatory status. Spinal metastasis should have a higher priority, and immediate intervention should be started before the development of irreversible neurologic deficits. Moreover, short-course radiotherapy might be a good option for patients with a limited life span. Consequently, the identified prognostic factors can be regarded as a preoperative assessment tool to predict neurologic outcome and guide clinical treatment for individual patients with MSCC. However, the retrospective nature of this study with low-quality evidence must be taken into account when interpreting these results, and further research is needed to identify prognostic factors.

Electrowetting on a lotus leaf.

Electrowetting on dielectrics has been widely used to manipulate and control microliter or nanoliter liquids in micro-total-analysis systems and laboratory on a chip. We carried out experiments on electrowetting on a lotus leaf, which is quite different from the equipotential plate used in conventional electrowetting. This has not been reported in the past. The lotus leaf is superhydrophobic and a weak conductor, so the droplet can be easily actuated on it through electrical potential gradient. The capillary motion of the droplet was recorded by a high-speed camera. The droplet moved toward the counterelectrode to fulfill the actuation. The actuation speed could be of the order of 10 mms. The actuation time is of the order of 10 ms.

The head-on colliding process of binary liquid droplets at low velocity: high-speed photography experiments and modeling.

The experimental and theoretical studies are reported in this paper for the head-on collisions of a liquid droplet with another of the same fluid resting on a solid substrate. The droplet on the hydrophobic polydimethylsiloxane (PDMS) substrate remains in a shape of an approximately spherical segment and is isometric to an incoming droplet. The colliding process of the binary droplets was recorded with high-speed photography. Head-on collisions saw four different types of response in our experiments: complete rebound, coalescence, partial rebound with conglutination, and coalescence accompanied by conglutination. For a complete rebound, both droplets exhibited remarkable elasticity and the contact time of the two colliding droplets was found to be in the range of 10-20 ms. With both droplets approximately considered as elastic bodies, Hertz contact theory was introduced to estimate the contact time for the complete rebound case. The estimated result was found to be on the same order of magnitude as the experimental data, which indicates that the present model is reasonable.

Influence of different amount of Au on the wetting behavior of PDMS membrane.

Polydimethylsiloxane (PDMS) has been widely used as a base material for bio-MEMS/NEMS devices. It is difficult for PDMS to transfer and spread aqueous solution as a kind of highly hydrophobic material. Therefore, surface modification is necessary for PDMS to make it hydrophilic. In this paper, a method of hydrophilization of PDMS surface is proposed. Gold is sputtered to the PDMS substrate by sputter coater in different average thicknesses. Relationship between the average thickness of gold on the PDMS substrate and the contact angle of the surface was studied. It was found that even gold of average thickness less than 1 nm can result in about 25 degrees change of contact angle. AFM is also used to get topographic information of PDMS surface coated with gold. Three cases are classified with different amount of Au: (1) Heterogeneous zone; (2) Transition zone; (3) Film zone. For heterogeneous zone, a simple model about heterogeneous phase wetting is put forward to interpret this phenomenon.