Three-Dimensionally-Printed Bioactive Ceramic Scaffolds: Construct Effects on Bone Regeneration.

BACKGROUND/PURPOSE: The utilization of three-dimensionally (3D)-printed bioceramic scaffolds composed of beta-tricalcium phosphate in conjunction with dipyridamole have shown to be effective in the osteogenesis of critical bone defects in both skeletally immature and mature animals. Furthermore, previous studies have proven the dura and pericranium's osteogenic capacity in the presence of 3D-printed scaffolds; however, the effect galea aponeurotica on osteogenesis in the presence of 3D scaffolds remains unclear. METHOD/DESCRIPTION: Critical-sized (11 mm) bilateral calvarial defects were created in 35-day old rabbits (n = 7). Two different 3D scaffolds were created, with one side of the calvaria being treated with a solid nonporous cap and the other with a fully porous cap. The solid cap feature was designed with the intention of preventing communication of the galea and the ossification site, while the porous cap permitted such communication. The rabbits were euthanized 8 weeks postoperatively. Calvaria were analyzed using microcomputed tomography, 3D reconstruction, and nondecalcified histologic sectioning in order assess differences in bone growth between the two types of scaffolding. RESULTS: Scaffolds with the solid (nonporous) cap yielded greater percent bone volume (P = 0.012) as well as a greater percent potential bone (P = 0.001) compared with the scaffolds with a porous cap. The scaffolds with porous caps also exhibited a greater percent volume of soft tissue (P < 0.001) presence. There were no statistically significant differences detected in scaffold volume. CONCLUSION: A physical barrier preventing the interaction of the galea aponeurotica with the scaffold leads to significantly increased calvarial bone regeneration in comparison with the scaffolds allowing for this interaction. The galea's interaction also leads to more soft tissue growth hindering the in growth of bone in the porous-cap scaffolds.

Pedometry as an External Measure of Spinal Cord Stimulation Patient Outcomes.

BACKGROUND: Chronic pain is a debilitating biologic and psychologic condition which affects nearly one third of the American population with an annual cost of $560 to $635 billion from associated health care costs and lost productivity. Treatment of chronic pain is difficult to objectively evaluate as it relies on subjective measure. An objective measure would be beneficial in assessing treatment efficacy and towards developing a closed loop system. We assess the efficacy of pedometry as an objective measure of treatment efficacy in spinal cord stimulation (SCS). METHODS: Participants who had back and/or leg pain and were scheduled for permanent thoracic SCS implantation were offered inclusion. Preoperatively and at three months post-operatively, patients underwent a battery of tests including the Oswestry Disability Index (ODI), Pain Catastrophization Scale (PCS), McGill Pain Questionnaire-Short Form (MPQ), Likert Pain Scale, Visual Analog Scale (VAS), Insomnia Severity Scale (ISS), and Epworth Sleepiness Scale (ESS). They also wore a pedometer for 48 hours prior to SCS implantation and for 48 hours at three months. Walking distance, step count, and steps per hour were documented. Additionally, patients were asked to record their activity level in hours per day. RESULTS: Eight patients completed three month follow-up. All measurements of disability and pain decreased significantly: ODI (p = 0.004), PCS (p = 0.01), MPQ (p = 0.02), VAS (p = 0.001), ISS (p = 0.002), and ESS (p = 0.041). All pain and disability measurements decreased independent of activity measures, except lowest levels of pain at the patient's best. A positive correlation was found between improvement in participant's active time and improvement in ESS score, suggesting decreased daytime sleepiness with increased time spent active (r = 0.844, N = 7, p = 0.017). CONCLUSIONS: We demonstrate a mean improvement of more than 50% in distance walked, steps per hour, and total steps. Interestingly, total activity (number of hours spent active per day) was not dramatically improved. Our data suggests that as a group our patients' ambulation increased dramatically after successful SCS. The use of pedometry in conjunction with self-reporting can lend both quantitative and qualitative validity to pain, as well as allow objective assessment of efficacy of SCS in patients suffering from chronic low back and/or leg pain. Further, external sensors tracking these data may be a means of creating a closed loop system with SCS.

The Use of Preoperative Psychological Evaluations to Predict Spinal Cord Stimulation Success: Our Experience and a Review of the Literature.

BACKGROUND: Pre-operative psychological assessment is commonly used to assess patients for spinal cord stimulation (SCS). Though often times mandated by insurance, its value is frequently questioned. METHODS: We review the literature on the predictive value of psychological testing prior to SCS and retrospectively examine our prospective database of SCS patients. We examine associations of Minnesota Multiphasic Personality Inventory (MMPI), Beck Depression Inventory (BDI), and Pain Catastrophizing Scale (PCS) findings and outcomes on the visual analog scale (VAS), McGill Pain Questionnaire - Short Form (MPQ), and Oswestry Disability Index (ODI) at 6 and 12 months post-implantation. RESULTS: The nine studies examining psychological predictors of SCS outcomes collectively showed that substance abuse or feelings of demoralization or less joy correlated with worse outcomes. Though not statistically significant, our data show that at one year follow-up, patients without psychiatric disorders improved 1.5 times as much on ODI and 2.4 times as much on PCS as compared to patients with psychiatric disorders. Further, depressed patients concurrently treated with anti-depressants had greater improvement in BDI than non-medicated depressed patients (p = 0.009). We develop a tool for pain psychologists based on the existing literature to aid in identifying possible concerns and treating these patients peri-operatively. DISCUSSION: The predictive value of psychological testing depends on which psychiatric factors are used and which outcomes are measured. The predictive capacity of psychological indications can be used to holistically treat patients, specifically to recommend psychiatric medication and consulting to supplement SCS treatment as needed.

Predictors of Spinal Cord Stimulation Success.

INTRODUCTION: As many as 30% of spinal cord stimulation (SCS) patients fail to obtain long-term pain coverage, even with the strictest parameters of a successful trial, unremarkable psychological assessment, and ideal placement of the permanent device. Why these patients either never receive adequate benefit or lose benefit remains elusive. METHODS: We perform a retrospective review of our prospective database of SCS patients undergoing surgery for routine indications. Six-month postoperative follow-up data were available for 57 patients. Two providers who routinely saw the patients were asked to independently grade the patient's outcome in a blinded fashion on a Global Outcome Ratings scale of 1 to 10, with 5 being 50% improvement at 6 months postoperation. A score of less than 5 was deemed a failure. The impact of body mass index (BMI), random drug screen results, workers' compensation status, depression, and smoking were assessed. RESULTS: We report a phi correlation of 0.350 between smoking and failure (p = 0.017). Smoking status is correlated with both lead migration revisions (phi = 0.269) (p = 0.044) and with revision due to new pain symptoms (phi = 0.241) (p = 0.072). Further, there is a trend of correlation (phi = 0.289) between drug use and patients (N = 3) who underwent device removal (p = 0.045). In this cohort, worker's compensation status, BMI, and depression did not impact outcome. CONCLUSIONS: Tobacco use correlates with less success with SCS at 6-month follow-up. Whether that is because of issues with healing and our transmission of signals to the periphery warrants further exploration. These data provide further evidence that tobacco cessation is important to surgical results.