Differential Target Multiplexed Spinal Cord Stimulation for the Treatment of Chronic Intractable Upper Limb Pain: 12-Month Results From a Prospective, Multicenter Study.

OBJECTIVES: This prospective, open-label, single-arm, multicenter study evaluated the use of differential target multiplexed (DTM) spinal cord stimulation (SCS) therapy for chronic upper limb pain (ULP). MATERIALS AND METHODS: A total of 58 candidates for SCS who had chronic ULP were enrolled at 11 sites in the USA. The safety and effectiveness of DTM SCS for treating chronic intractable ULP were evaluated over 12 months. The primary end point was the percentage of responders (≥50% ULP relief versus baseline) to treatment at three months after device activation. This study also evaluated the extent of disability, patient satisfaction, and patient global impression of change with DTM SCS therapy. RESULTS: The mean baseline pain score (10-cm visual analog scale [VAS-10]) for ULP was 7.2 cm, with a mean age of 56 years and mean ULP duration of ten years; 47 subjects were assessed at the primary end point. The percentage of ULP responders was 92% at three months, which was consistent at six (91%) and 12 months (86%). Significant ULP relief (81% reduction in VAS-10) was observed at the primary end point and sustained throughout the study duration. Significant improvements in disability in addition to high levels (>95%) of satisfaction and feelings of improvement were reported. Frequency of study-related anticipated adverse events was in line with expectations of SCS therapy. CONCLUSION: In this patient population with difficult-to-treat conditions with limited clinical evidence of the effectiveness of SCS, subjects reported significant reduction in chronic ULP in response to treatment with DTM SCS.

Twelve-month results from a randomized controlled trial comparing differential target multiplexed spinal cord stimulation and conventional spinal cord stimulation in subjects with chronic refractory axial low back pain not eligible for spine surgery.

Background: Successful treatments for intractable chronic low back pain (CLBP) in patients who are not eligible for surgical interventions are scarce. The superior efficacy of differential target multiplexed spinal cord stimulation (DTM SCS) to conventional SCS (Conv-SCS) on the treatment of CLBP in patients with persistent spinal pain syndrome (PSPS) who have failed surgical interventions (PSPS-T2) motivated the evaluation of DTM SCS versus Conv-SCS on PSPS patients who are non-surgical candidates (PSPS-T1). Methods: This is a prospective, open label, crossover, post-market randomized controlled trial in 20 centers across the United States. Eligible patients were randomized to either DTM SCS or Conv-SCS in a 1:1 ratio. Primary endpoint was CLBP responder rate (percentage of subjects with ≥50% CLBP relief) at 3-month in randomized subjects who completed trialing (modified intention-to-treat population). Patients were followed up to 12 months. Secondary endpoints included change of CLBP and leg pain, responder rates, changes in disability, quality of life, patient satisfaction and global impression of change, and safety profile. An optional crossover was available at 6-month to all patients. Results: About 121 PSPS-T1 subjects with CLBP and leg pain mostly associated with degenerative disc disease and radiculopathy and who were not eligible for spine surgery were randomized. CLBP responder rate with DTM SCS (93.5%) was superior to Conv-SCS (36.4%) at the primary endpoint. Superior CLBP responder rates (88.1%-90.5%) were obtained with DTM SCS at all other timepoints. Mean CLBP reduction with DTM SCS (6.52 cm) was superior to that with Conv-SCS (3.01 cm) at the primary endpoint. Similar CLBP reductions (6.23-6.43 cm) were obtained with DTM SCS at other timepoints. DTM SCS provided significantly better leg pain reduction and responder rate, improvement of disability and quality of life, and better patient satisfaction and global impression of change. 90.9% of Conv-SCS subjects who crossed over were CLBP responders at completion of the study. Similar safety profiles were observed between the two groups. Conclusion: DTM SCS for chronic CLBP in nonsurgical candidates is superior to Conv-SCS. Improvements were sustained and provided significant benefits on the management of these patients.

Body contouring after bariatric surgery: how much is really being done?

The proportion of postbariatric surgery patients who undergo body contouring (BC) procedures is unknown. We designed a study to explore demographic features and patient education regarding BC in the bariatric surgery (BS) population. A survey was mailed to 1158 patients who underwent BS by 2 surgeons between 2003 and 2011. A total of 284 (24.5%) patients responded. Seventy-two patients (25.4%) reported discussing BC surgery with their bariatric surgeon perioperatively. Forty patients (14.1%) were referred for plastic surgery consultation. Thirty-three patients (11.6%) underwent BC procedures. The most frequent reasons cited for not undergoing BC were expense (29.2%) and lack of awareness regarding options (23.6%). Thirty-nine percent of respondents reported that they might have chosen differently, had they received more information. As a result of insufficient perioperative counseling, the majority of BS patients are unaware of the multitude of BC procedures available. Additional efforts toward improving patient (and surgeon) education regarding postbariatric BC options are warranted.

Developmental cardiac hypertrophy in a mouse model of prolidase deficiency.

BACKGROUND: Hypertrophic cardiomyopathy, characterized by thickened ventricular walls and reduced ventricular chamber volume, is a common cause of sudden cardiac death in young people. Most inherited forms result from mutations in genes encoding sarcomeric proteins. METHODS: Histologic analysis identified embryonic cardiac hypertrophy in dark-like mutant mice. BrdU analysis was performed to measure proliferation and cardiomyocytes were isolated to measure cell size. The dark-like mutation was identified by positional cloning. RESULTS: The dark-like mutation causes cardiomyocyte hypertrophy due to loss-of-function of peptidase d (Pepd), which encodes prolidase, a cytosolic enzyme that recycles proline for collagen re-synthesis. Prolidase deficiency is a rare autosomal recessive disease in humans with a broad phenotypic spectrum not reported to include heart defects, but a conserved role for prolidase in heart development was confirmed by morpholino knockdown in zebrafish. We tested the hypothesis that loss of prolidase function disrupts collagen-mediated integrin signaling and determined that the levels of several key integrin transducers were reduced in the hearts of dark-like mutant embryos. CONCLUSIONS: This work identifies dark-like mice as a model of prolidase deficiency that will be valuable for studying the role of proline metabolism in normal physiology and disease processes, and suggests that integrin signaling may regulate the onset of hypertrophic cardiac growth.

Genetic and phenotypic studies of the dark-like mutant mouse.

The dark-like (dal) mutant mouse has a pleiotropic phenotype that includes dark dorsal hairs and reproductive degeneration. Their pigmentation phenotype is similar to Attractin (Atrn) mutants, which also develop vacuoles throughout the brain. In further characterizing the testicular degeneration of dal mutant males, we found that they had reduced serum testosterone and developed vacuoles in their testes. Genetic crosses placed dal upstream of the melanocortin 1 receptor (Mc1r) and downstream of agouti, although dal suppressed the effect of agouti on pigmentation but not body weight. Atrn(mg-3J) and dal showed additive effects on pigmentation, testicular vacuolation, and spongiform neurodegeneration, but transgenic overexpression of Attractin-like-1 (Atrnl1), which compensates for loss of ATRN, did not rescue dal mutant phenotypes. Our results suggest dal and Atrn function in the same pathway and that identification of the dal gene will provide insight into molecular mechanisms of vacuolation in multiple cell types.

Tissue engineering and biomaterials in regenerative medicine.

The field of regenerative medicine offers the potential to significantly impact a wide spectrum of healthcare issues, from diabetes to cardiovascular disease. In particular, the design of tailored biomaterials, which possess properties desired for their particular application, and the development of superior implant environments, which seek to meet the nutritional needs of the tissue, have yielded promising tissue engineering prototypes. In this commentary, we examine the novel approaches researchers have made in customized biomaterials and promoting angiogenesis that have led to significant advancements in recent years.