Anterior Lumbar Interbody Fusion Integrated Screw Cages: Intrinsic Load Generation, Subsidence, and Torsional Stability.

OBJECTIVE: To perform a repeatable idealized in vitro model to evaluate the effects of key design features and integrated screw fixation on unloaded surface engagement, subsidence, and torsional stability. METHODS: We evaluated four different stand-alone anterior lumbar interbody fusion (ALIF) cages with two, three, and four screw designs. Polyurethane (saw-bone) foam blocks were used to simulate the vertebral bone. Fuji Film was used to measure the contact footprint, average pressure, and load generated by fixating the cages with screws. Subsidence was tested by axially loading the constructs at 10 N/s to 400 N and torsional load was applied +/-1 Nm for 10 cycles to assess stability. Outcome measures included total subsidence and maximal torsional angle range. RESULTS: Cages 1, 2, and 4 were symmetrical and produced similar results in terms of contact footprint, average pressure, and load. The addition of integrated screws into the cage-bone block construct demonstrated a clear trend towards decreased subsidence. Cage 2 with surface titanium angled ridges and a keel produced the greatest subsidence with and without screws, significantly more than all other cages ( P < 0.05). Angular rotation was not significantly affected by the addition of screws ( P < 0.066). A statistically significant correlation existed between subsidence and reduced angular rotation across all cage constructs ( P = 0.018). CONCLUSION: Each stand-alone cage featured unique surface characteristics, which resulted in differing cage-foam interface engagement, influencing the subsidence and torsional angle. Increased subsidence significantly reduced the torsional angle across all cage constructs.

Percutaneous Transcatheter Interventions for Aortic Insufficiency in Continuous-Flow Left Ventricular Assist Device Patients: A Systematic Review and Meta-Analysis.

De novo progressive aortic insufficiency (AI) is a side effect frequently related to prolonged support with continuous-flow left ventricular assist devices (CF-LVAD). Its progression can result in recurrent clinical heart failure symptoms and significantly increased mortality. Recently, percutaneous intervention methods, such as transcatheter aortic valve replacement (TAVR) and percutaneous occluder devices, have emerged. However, given the very scarce global experience with these approaches, evidence in the literature is lacking. We sought to assess the outcomes of CF-LVAD patients who had undergone percutaneous intervention for AI. A systematic search of six databases from inception to April 2016 was performed by two independent reviewers. Eligible studies were those that included series or cases where patients had percutaneous transcatheter interventions for AI in CF-LVAD patients. Data were extracted and meta-analyzed from the identified studies. A total of 29 patients from 15 published studies and 3 unpublished records were included in the analysis. Mean patient age was 56.6 ± 13.7 years, and 72.4% were male. The etiology of heart failure resulting in LVAD placement was ischemic cardiomyopathy in 17.2%. The two intervention groups were TAVR (27.6%) and occluder devices (72.4%). A transfemoral approach (69%), apical approach (10%), brachial approach (7%), subclavian approach (3%), and mini-sternotomy (3%) were used. The preintervention AI grade was severe with a median grade of 4 (interquartile range, 4-4). Postoperatively, the AI grade improved significantly to a median grade of 0 (0-2). At long-term follow-up AI grade was still trivial with a median AI grade of 1 (0-1). Subgrouping the treatments into the occluder device and TAVR, it was found that both interventional techniques were similarly effective in reducing the AI grade from severe to trivial. In terms of complications, from the occluder group, two patients were complicated with device migration and another two with transient hemolysis. In the TAVR cohort, two patients experienced device migration and another had significant postimplant perivalvular leakage. Our results indicate that percutaneous interventions for AI in CF-LVAD patients with TAVR, and closure devices demonstrate similar efficacy in significantly reducing severe AI. Current results are encouraging, potentiating viability as a treatment option, particularly in nonsurgical candidates. Future research with larger patient cohorts and comparative controls is required to sufficiently evaluate the efficacy of this technique and promote its widespread acceptance as a mainstay treatment.

Radiological and clinical outcomes of novel Ti/PEEK combined spinal fusion cages: a systematic review and preclinical evaluation.

PURPOSE: The primary objective of this paper was to provide a systematic review of the available clinical studies of Ti/PEEK combined cages in spinal interbody fusion surgeries, focusing on their radiological and clinical outcomes. A secondary aim was to provide a review and evaluation of the in vitro and preclinical studies reported on Ti/PEEK-coated implants. METHODS: A systematic search of the literature was performed in March 2015 via three databases: Medline, Embase and Cochrane library. The following key search terms were combined with synonyms to identify relevant articles: "spinal fusion," "PEEK," "titanium" and "cage." RESULTS: The novelty of this intervention translates into a paucity of clinical trials, albeit the results of the seven clinical studies that met the criteria for inclusion are promising. All studies reported rate of fusion as a primary outcome. Two studies reported slightly improved fusion in the experimental Ti/PEEK combination cohort, one study identical fusion (91.7 %) and three studies excellent fusion (96, 100 and 94 %) in the Ti/PEEK cohort, although no differences reached statistical significance. CONCLUSIONS: Clinical studies at this early stage demonstrate that Ti/PEEK implants are safe and efficacious, exhibiting similar fusion rates and clinical outcomes compared to the current standard PEEK. There is clinical evidence substantiating the improved radiographic fusion of Ti/PEEK, albeit the differences were not significant. This field is promising, gaining substantial popularity, and further clinical trials are needed in the future to establish Ti/PEEK cages as a mainstay of clinical practice.

The over-representation of significant p values in abstracts compared to corresponding full texts: A systematic review of surgical randomized trials.

BACKGROUND: Abstracts are often the only read summaries of research findings, and it is essential that they accurately represent of the contents of the full text of the randomised control trial (RCT). We investigated whether outcomes in surgical trials were selectively reported in abstracts based on their statistical significance. OBJECTIVE: To compare the proportion of significant p-values reported in abstracts to their corresponding full texts in surgical RCTs. METHOD: A Meta-analysis of 350 full text RCTs conducted on humans that compared a surgical intervention to any other intervention. An electronic search of MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) was conducted. All outcomes were extracted from the abstract and the full text. Frequency histograms were used to plot the distribution of numerically reported p-values across the statistical significance spectrum. For each RCT, a 2 × 2 table was populated with that trial's outcomes and whether the outcome was statistically significant (p < 0.05). From each 2 × 2 table, an odds ratio (OR) was calculated describing the association between statistical significance, and reporting in the abstract. ORs were pooled in random effects meta-analysis for an overall estimate of the association. RESULTS: A total of 8258 reported outcomes were included. Outcomes reported in a surgical RCT abstract had three times the odds of being significant when compared to the corresponding full text (OR = 3.0, 95% confidence interval 2.5-3.6, p < 0.001). This finding was consistent and not subject to heterogeneity (I2 = 0%). Both histograms demonstrated a large drop in the frequency of reported p values between 0.04 and 0.05, and after the 0.06 thresholds. CONCLUSIONS: Data presented in abstracts is biased to statistically significant outcomes. Clinicians and policy makers should do not rely solely on information presented in abstracts for their decision-making.

Combination Ti/PEEK ALIF cage for anterior lumbar interbody fusion: Early clinical and radiological results.

Anterior lumbar interbody fusion (ALIF) is a common procedure for patients with degenerative pathologies of the lumbar spine. In this study, the clinical and radiological outcomes of a combination titanium/polyetheretherketone (Ti/PEEK) ALIF cages in one, two and three-level surgery were evaluated. Over an 18-month time period, a prospective single surgeon series of 20 implants (15 patients) were included in the study, with minimum 10-months follow-up. From these 15 patients, two were supplemented with posterior percutaneous pedicle screw fixation for additional stability. Radiological follow-up with fine cut CT scan at 9-12months was performed to evaluate early fusion rates, and integration of the Titanium/PEEK cage at the endplate junction. 20 implants were followed for a minimum of 10months, and a mean of 15months. A 95% (19/20 implants) fusion rate with no implant related complications was achieved at the mean 15-month postoperative mark. Patients experienced statistically significant improvement in pain and functional outcomes (SF12 and ODI) compared to their pre-operative status. A single patient with a non-union at L5/S1 (smoker) did not experience any improvement in symptoms. A Ti-PEEK cage, with allograft and BMP-2 to achieve interbody fusion is an effective implant for use in anterior lumbar surgery with high fusion rates, no lucency around the titanium endplates at follow-up, and with promising early results.

Review of early clinical results and complications associated with oblique lumbar interbody fusion (OLIF).

Lumbar interbody fusion represents an effective surgical intervention for patients with lumbar degenerative diseases, spondylolisthesis, disc herniation, pseudoarthrosis and spinal deformities. Traditionally, conventional open anterior lumbar interbody fusion and posterior/transforaminal lumbar interbody fusion techniques have been employed with excellent results, but each with their own advantages and caveats. Most recently, the antero-oblique trajectory has been introduced, providing yet another corridor to access the lumbar spine. Termed the oblique lumbar interbody fusion, this approach accesses the spine between the anterior vessels and psoas muscles, avoiding both sets of structures to allow efficient clearance of the disc space and application of a large interbody device to afford distraction for foraminal decompression and endplate preparation for rapid and thorough fusion. This review aims to summarize the early clinical results and complications of this new technique and discusses potential future directions of research.

PEEK-Halo effect in interbody fusion.

Recent developments have seen poly[aryl-ether-ether-ketone] (PEEK) being increasingly used in vertebral body fusion. More novel approaches to improve PEEK have included the introduction of titanium-PEEK (Ti-PEEK) composites and coatings. This paper aims to describe a potential complication of PEEK based implants relating to poorer integration with the surrounding bone, producing a "PEEK-Halo" effect which is not seen in Ti-PEEK composite implants. We present images from two patients undergoing anterior lumbar interbody fusion (ALIF). The first patient underwent an L5/S1 ALIF using a PEEK implant whilst the second patient underwent L4/L5 ALIF using a Ti-PEEK composite implant. Evidence of osseointegration was sought using CT imaging and confirmed using histological preparations of a sheep tibia model. The PEEK-Halo effect is demonstrated by a halo effect between the PEEK implant and the bone graft on CT imaging. This phenomenon is secondary to poor osseointegration of PEEK implants. The PEEK-Halo effect was not demonstrated in the second patient who received a Ti-PEEK composite graft. Histological analysis of graft/bone interface surfaces in PEEK versus Ti-PEEK implants in a sheep model further confirmed poorer osseointegration of the PEEK implant. In conclusion, the PEEK-Halo effect is seen secondary to minimal osseointegration of PEEK at the adjacent vertebral endplate following a PEEK implant insertion. This effect is not seen with Ti-PEEK implants, and may support the role of titanium in improving the bone-implant interface of PEEK substrates.

Glyceryl trinitrate patches-An alternative treatment for shoulder impingement syndrome.

Transdermal glyceryl trinitrate patches have been investigated as an alternative therapeutic intervention for a range of tendinopathies, due to the ease of titration of dosage and the ease of their application. Glyceryl trinitrate has been inferred to reduce pain and inflammation secondary to their nitric oxide-producing action. Shoulder impingement syndrome is a soft tissue condition that manifests as anterior shoulder pain, weakness, and difficulty in daily activities. This review will evaluate the efficacy of glyceryl trinitrate patches in treating a variety of rotator cuff tendinopathies related to shoulder impingement, based on human and animal trials, and suggest its practical application in future trials and management.