Is Response to a Pre-implant Diagnostic Peripheral Nerve Block Associated With Efficacy After Peripheral Nerve Stimulation Implantation? A Ten-Year Enterprise-Wide Analysis.

OBJECTIVES: This study aimed to assess whether patient response to targeted diagnostic peripheral nerve block before peripheral nerve stimulator (PNS) device implantation is associated with efficacy after PNS implantation. MATERIALS AND METHODS: The electronic medical records from the Mayo Clinic Enterprise (three quarternary care medical centers and additional satellite medical centers) were reviewed to identify patients who underwent PNS implantation between January 2014 and January 2023. A primary outcome of interest was to assess whether administration of a preimplant diagnostic peripheral nerve block predicted pain relief at three months and six months after temporary and permanent PNS implantation. Another primary outcome was to investigate whether there was an association between the pain relief from a preimplant diagnostic peripheral nerve block and pain relief after three and six months after temporary or permanent PNS therapy. Linear regression analysis was conducted for outcomes of interest. RESULTS: Of 193 eligible patients who underwent PNS therapy, a total of 173 patients were included in the final analysis and were stratified into either the temporary PNS cohort (n = 112) or the permanent PNS cohort (n = 61). Overall, 77.5% of all patients (134/173) underwent a preimplant diagnostic peripheral nerve block and reported a mean percentage relief of 70.1 ± 27.0 from the diagnostic block. Of patients in the temporary PNS cohort, there was no difference in postimplant percentage pain relief between patients who received a diagnostic block (n = 93) and control patients (n = 19) at three months (35.4 ± 36.0 vs 49.8 ± 36.1, respectively; ß -14.45, 95% CI -32.98 to 4.07, p = 0.125) or at six months (23.3 ± 30.8 vs 45.7 ± 40.0, respectively; ß -22.39, 95% CI -46.86 to 2.08, p = 0.072). Of patients in the permanent PNS cohort, there was no difference in postimplant percentage pain relief between patients who received a diagnostic block (n = 41) and control patients (n = 20) at three months (42.4 ± 34.3 vs 43.2 ± 42.4, respectively; ß -0.79, 95% CI -23.56 to 21.99, p = 0.945) or at six months (44.3 ± 35.0 vs 38.8 ± 40.9, respectively; ß 5.42, 95% CI -20.04 to 30.88, p = 0.669). Pain relief from preimplant diagnostic blocks was associated with postimplant pain relief from temporary PNS at three months (ß 0.33, 95% CI 0.04-0.61, p = 0.025). However, pain relief from preimplant diagnostic blocks did not predict postimplant pain relief from temporary PNS at six months, or permanent PNS at three months and six months. CONCLUSIONS: Administration of a diagnostic block is not associated with superior pain relief at three or six months after PNS implantation to that of an approach without diagnostic block. Pain relief from a diagnostic block may potentially predict short-term pain relief after temporary PNS therapy, although future prospective studies are warranted to evaluate the prognostic utility of diagnostic blocks.

Adverse Events Associated With 10-kHz Dorsal Column Spinal Cord Stimulation: A 5-Year Analysis of the Manufacturer and User Facility Device Experience (MAUDE) Database.

BACKGROUND: High-frequency (10-kHz) spinal cord stimulation (SCS) continues to be an emerging therapy in chronic pain management. The same complications that plagued earlier SCS systems may affect newer stimulation technologies, although there is limited data on the type of complications and surgical management of these complications. OBJECTIVE: The aim of this study was to systematically examine real-world complications associated with 10-kHz SCS reported on the Manufacturer and User Facility Device Experience (MAUDE) database. MATERIALS AND METHODS: The MAUDE database was queried for entries reported between January 1, 2016 and December 31, 2020. Entries were classified into procedural complications, device-related complications, patient complaints, surgically managed complications, serious adverse events, and/or other complications. Primary outcomes included type and frequency of complications, and surgical management of complications. RESULTS: A total of 1651 entries were analyzed. Most entries were categorized as procedural complications (72.6%), followed by serious adverse events (10.5%), device-related complications (10.5%), and patient complaints (9.9%). Most complications were managed surgically with explant (50.9%) rather than revision (5.0%) or incision/drainage (6.6%). Of procedural complications, the most common entries included non-neuraxial infection (52.9%), new neurological symptoms (14.7%), and dural puncture (9.5%). Of device-related complications, the most common entries included lead damage (41.6%), erosion (18.5%), and difficult insertion (11.5%). CONCLUSION: This retrospective 5-year analysis of complications from10-kHz SCS provides a real-world assessment of safety data unique for this stimulation modality. This analysis may help inform future clinical decisions, lead to device enhancement and optimization, and improve mitigation of risks to provide safe and efficacious use of 10-kHz SCS.

Blame it on the injury: Trauma is a risk factor for pancreatic fistula following distal pancreatectomy compared with elective resection.

BACKGROUND: Postoperative pancreatic fistula (POPF) remains a significant source of morbidity following distal pancreatectomy (DP). There is a lack of information regarding the impact of trauma on POPF rates when compared with elective resection. We hypothesize that trauma will be a significant risk factor for the development of POPF following DP. METHODS: A retrospective, single-institution review of all patients undergoing DP from 1999 to 2017 was performed. Outcomes were compared between patients undergoing DP for traumatic injury to those undergoing elective resection. Univariate and multivariable analyses were performed using SAS (version 9.4). RESULTS: Of the 372 patients who underwent DP during the study period, 298 met inclusion criteria: 38 DPs for trauma (TDP), 260 elective DPs (EDP). Clinically significant grade B or C POPFs occurred in 17 (44.7%) of 38 TDPs compared with 41 (15.8%) of 260 EDPs (p < 0.0001). On multivariable analysis, traumatic injury was found to be independently predictive of developing a grade B or C POPF (odds ratio, 4.3; 95% confidence interval, 2.10-8.89). Age, sex, and wound infection were highly correlated with traumatic etiology and therefore were not retained in the multivariable model. When analyzing risk factors for each group (trauma vs. elective) separately, we found that TDP patients who developed POPFs had less sutured closure of their duct, higher infectious complications, and longer hospital stays, while EDP patients that suffered POPFs were more likely to be male, younger in age, and at a greater risk for infectious complications. Lastly, in a subgroup analysis involving only patients with drains left postoperatively, trauma was an independent predictor of any grade of fistula (A, B, or C) compared with elective DP (odds ratio, 8.6; 95% confidence interval, 3.09-24.15), suggesting that traumatic injury is risk factor for pancreatic stump closure disruption following DP. CONCLUSION: To our knowledge, this study represents the largest cohort of patients comparing pancreatic leak rates in traumatic versus elective DP, and demonstrates that traumatic injury is an independent risk factor for developing an ISGPF grade B or C pancreatic fistula following DP. LEVEL OF EVIDENCE: Prognostic study, Therapeutic, level III.

Tobacco Smoking Associated With Increased Anastomotic Disruption Following Pancreaticoduodenectomy.

BACKGROUND: The effect of cigarette smoking on postoperative morbidity following pancreaticoduodenectomy (PD) for cancer is unclear. We hypothesize that smoking is associated with higher morbidity following PD. METHODS: A retrospective review of patients undergoing PD for cancer from 2010 to 2016 at a single institution was performed. Patients who had never smoked were compared to current or past-smokers with at least 1 pack-year history. Univariate and multivariable analyses were performed. RESULTS: Two hundred fifty-two patients met inclusion criteria. On univariate analysis, there was a significant difference between smokers and never-smokers in age at diagnosis (65.5 versus 68.6 y, P = 0.013) and fistula rate (28.5% versus 16.2%, P = 0.024). Male sex was significantly associated with fistula rate compared with female sex (15.5% versus 7.1%, P = 0.023). Comparing males and females separately, smoking correlated with higher fistula development only in the male cohort (22.5% versus 5.8%, P = 0.016 in men and 7.3% versus 9.1%, P = 1.00 in women). On multivariable analysis, current and past smoking was independently predictive of developing a fistula: odds ratio of 2.038 (P = 0.030). For current and past-smokers, male sex was an independent risk factor for developing a fistula: odds ratio 2.817 (P = 0.022). There were no other significant differences between groups in rates of postoperative complications. CONCLUSIONS: Smoking status is independently predictive of postoperative pancreatic fistula following PD for cancer. Among smokers, male sex is an independent risk factor for fistula. Further studies are needed to determine if smoking cessation before surgery decreases this risk, and if so, the optimal duration of cessation.

Morphological and physiological regeneration in the auditory system of adult Mecopoda elongata (Orthoptera: Tettigoniidae).

Orthopterans are suitable model organisms for investigations of regeneration mechanisms in the auditory system. Regeneration has been described in the auditory systems of locusts (Caelifera) and of crickets (Ensifera). In this study, we comparatively investigate the neural regeneration in the auditory system in the bush cricket Mecopoda elongata. A crushing of the tympanal nerve in the foreleg of M. elongata results in a loss of auditory information transfer. Physiological recordings of the tympanal nerve suggest outgrowing fibers 5 days after crushing. An anatomical regeneration of the fibers within the central nervous system starts 10 days after crushing. The neuronal projection reaches the target area at day 20. Threshold values to low frequency airborne sound remain high after crushing, indicating a lower regeneration capability of this group of fibers. However, within the central target area the low frequency areas are also innervated. Recordings of auditory interneurons show that the regenerating fibers form new functional connections starting at day 20 after crushing.