Explantation Rates of High Frequency Spinal Cord Stimulation in Two Outpatient Clinics.

OBJECTIVES: To report the explantation rates of high frequency 10 kHz spinal cord stimulation (SCS) in a real-world setting. MATERIALS AND METHODS: This is a retrospective review of patients implanted with high frequency spinal cord stimulators over a 4-year period in two outpatient private practice clinics, from July 2015 through June 2019, using the Kaplan-Meier product-limit method to estimate probabilities of implant survival over time. RESULTS: The estimated median time to explantation was 3.5 years (95% confidence interval [CI] = 3.1-3.7) [Correction added on 15 October 2020, after first online publication: The preceeding sentence was amended to reflect the estimated median time.]. The estimated probabilities of implant survival beyond 1, 2, and 3 years postimplantation were 88.4% (95% CI = 81.3-93.0%), 76.5% (95% CI = 67.8-83.2%), and 60.7% (95% CI = 50.2-69.6%), respectively. The minimum (i.e., known) cumulative percentages of patients explanted by 1, 2, and 3 years postimplantation were 11.1% (14/126), 22.2% (28/126), and 32.5% (41/126), respectively. 65.9% of patients in this study had prior neurostimulation. CONCLUSIONS: Recently, high frequency SCS technology has been demonstrated as more effective in treatment of lower- and leg-pain, compared to conventional low frequency SCS, in a 12-month randomized controlled trial (SENZA-RCT). Longer term results have yet to be published. In this study, we found that the explantation rate was much higher than expected, based on the prior studies demonstrating its efficacy. As the use of neuromodulation continues to grow, longitudinal data will be critical in understanding its long-term effects on treated patients.

Convolutional Neural Network Detection of Axillary Lymph Node Metastasis Using Standard Clinical Breast MRI.

BACKGROUND: Axillary lymph node status is important for breast cancer staging and treatment planning as the majority of breast cancer metastasis spreads through the axillary lymph nodes. There is currently no reliable noninvasive imaging method to detect nodal metastasis associated with breast cancer. MATERIALS AND METHODS: Magnetic resonance imaging (MRI) data were those from the peak contrast dynamic image from 1.5 Tesla MRI scanners at the pre-neoadjuvant chemotherapy stage. Data consisted of 66 abnormal nodes from 38 patients and 193 normal nodes from 61 patients. Abnormal nodes were those determined by expert radiologist based on 18Fluorodeoxyglucose positron emission tomography images. Normal nodes were those with negative diagnosis of breast cancer. The convolutional neural network consisted of 5 convolutional layers with filters from 16 to 128. Receiver operating characteristic analysis was performed to evaluate prediction performance. For comparison, an expert radiologist also scored the same nodes as normal or abnormal. RESULTS: The convolutional neural network model yielded a specificity of 79.3% ± 5.1%, sensitivity of 92.1% ± 2.9%, positive predictive value of 76.9% ± 4.0%, negative predictive value of 93.3% ± 1.9%, accuracy of 84.8% ± 2.4%, and receiver operating characteristic area under the curve of 0.91 ± 0.02 for the validation data set. These results compared favorably with scoring by radiologists (accuracy of 78%). CONCLUSION: The results are encouraging and suggest that this approach may prove useful for classifying lymph node status on MRI in clinical settings in patients with breast cancer, although additional studies are needed before routine clinical use can be realized. This approach has the potential to ultimately be a noninvasive alternative to lymph node biopsy.

Peripheral nerve field stimulation in chronic abdominal pain.

INTRODUCTION: Spinal Cord Stimulation (SCS) has become an accepted therapeutic modality for the treatment of intractable pain syndromes, primarily used today in the settings of failed back surgery syndrome, neuropathic back and limb pain. The use of spinal cord stimulators for peripheral nerve field electrostimulation is becoming increasingly recognized as a safe, effective alternative for chronic pain conditions that are refractory to medical management and do not respond to traditional dorsal column stimulation. Advances in technology have allowed for minimally invasive percutaneous placement of multipolar leads with complex programmable systems to provide patient- controlled relief of pain in precisely targeted regions. With these improvements in hardware, the use of Peripheral Nerve Field Stimulation (PNFS) appears to have an untapped potential for providing patients with pain relief for a wider range of underlying conditions than was previously believed possible. We present three cases, each with a different etiology of chronic abdominal pain: one with inguinal neuralgia, one with chronic pancreatitis, and one with pain following liver transplant. Each patient was refractory to conventional medical approaches. For all three patients, PNFS provided significant relief from pain, enabling patients to decrease or discontinue their opioid medications and to enjoy significant improvement in their quality of life. We conclude that PNFS is a safe, effective and minimally invasive treatment that may be used successfully for a wide variety of indications including chronic abdominal pain.

Spinal cord stimulation in conjunction with peripheral nerve field stimulation for the treatment of low back and leg pain: a case series.

Background. The treatment of chronic low back and leg pain remains a difficult medical challenge, particularly for patients with postlaminectomy syndrome. While spinal cord stimulation (SCS) has been a significant addition to the available options, it is often inadequate in relieving both the back and leg pain components. We hypothesized that for some patients the combination of SCS with peripheral nerve field stimulation (PNFS) would be a safe, effective alternative that would be more effective than either modality alone. Objective. Our objective was to demonstrate the efficacy of PNFS used in combination with SCS for the treatment of chronic pain syndromes involving the lower back and legs. Study Design. Case series. Methods. A total of 20 patients with chronic low back and leg pain syndromes who had failed conventional therapies underwent implantation of a combination of traditional SCS and PNFS. Leads were placed in the epidural space, as well as superficially in the subcutaneous tissues of the lower back, directly in the region of maximum pain. Patients initially underwent a trial of stimulation to assess response, and a permanent system was implanted if patients reported greater than 50% pain relief during the trial. For some patients, a combination was used at the time of the initial trial. In other cases, the decision to proceed with the combination was made later, either at the time of permanent implant, or later on, after SCS alone failed to adequately control pain. Results. In each case, PNFS was used in combination with traditional SCS for patients with chronic lower back and lower extremity pain. While not all of these patients ultimately proceeded with the combination of SCS and PNFS to control their pain, the majority of patients found the combination better in controlling their overall pain than either modality alone. In addition, using a combined approach at the time of trial provided a noninvasive and effective method of comparing the efficacy of each method, allowing patients to identify the best form of neuromodulation for their particular pain. Conclusions. Due to the availability of 16 contact capacity generators, neurostimulation with multiple leads in various combinations-including both epidural and peripheral nerve field stimulation simultaneously-can be applied safely and effectively. The availability of this combined approach for a trial of stimulation prior to implant allows patients to compare SCS to PNFS and to indicate a preference for one over the other or for the combination. We conclude that PNFS may be used in combination with SCS as a safe and effective alternative treatment for patients with chronic low back and leg pain, and further suggest that the combined approach should be considered as a treatment option for this population.

Peripheral Nerve Field Stimulation for the Treatment of Chronic Low Back Pain: Preliminary Results of Long-Term Follow-up: A Case Series.

Objective. Our objective was to determine the efficacy of peripheral nerve field stimulation (PNFS) for the treatment of chronic lower back pain. PNFS is becoming increasingly recognized as a safe, minimally invasive, and easily reversible treatment for a variety of chronic pain conditions. Chronic low back pain is a common cause of disability and one that is difficult to treat effectively. We hypothesized that PNFS would be a safe, effective alternative for patients with chronic low back pain, which has not been previously reported. Materials and Methods. Six patients with chronic low back pain who had failed conventional therapies were implanted in the subcutaneous tissues of the low back region with neurostimulation leads. Leads were placed superficially in the region of maximum pain, as identified by each individual patient. Patients initially underwent a trial of stimulation to assess response, and a permanent system was subsequently implanted if patients reported greater than 50% pain relief in the low back during the trial. Results. In each case presented here, PNFS enabled patients to decrease their pain medication and increase their level of activity. The patients all reported reduction in pain as measured by visual analog scale scores and an improved quality of life. Conclusion. We conclude that PNFS is a safe and effective alternative treatment for patients with chronic low back pain, and should be considered in this population.