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Objective: The purpose of this study was to assess and compare the humidification, heating, and resistance properties of three commercially available heat-moisture exchangers (HMEs). To mimic clinical conditions, a previously validated, new, realistic experimental set-up and measurement protocol was used.Design: Prospective, comparative experimental study.Setting: Surgical Intensive Care Unit, University Hospital of Rotterdam.Materials: An experimental set-up consisting of a patient model, measurement systems, and ventilator and three different HME types.Interventions: The air flow, pressure in the ventilation circuit, pressure difference over the HME, and partial water vapour pressure and temperature at each side of the HMEs were measured. Measurements were repeated every 30 min during the first 2 h and every hour up to 24 h for each HME at six different ventilator settings. The mean inspiratory and maximum expiratory resistance, flow-weighted mean absolute humidity and temperature outputs, and humidification and heating efficiencies of HMEs were calculated.Measurements and Results: The Dar Hygroster had the highest humidity output, temperature output, humidification efficiency, and heating efficiency values throughout the study (32.8 +/- 21. mg/l, 32.2 +/- 0.8 degrees C, 86.3 +/- 2.3%, and 0.9 +/- 0.01%, respectively) in comparison to the Humid-Vent Filter (25.3 +/- 3.2 mg/l, 31.9 +/- 0.8 degrees C, 72.2 +/- 5.3%, 0.9 +/- 0.02%, respectively) and the Pall Ultipor BB100 breathing circuit filter (23.4 +/- 3 mg/l, 28.3 +/- 0.7 degrees C, 68.8 +/- 5.9%, 0.8 +/- 0.02%, respectively). The inspiratory and expiratory resistance of the HMEs remained below clinically acceptable maximum values (2.60 +/- 0.04 and 2.45 +/- 0.05 cmH2O/l per s, respectively).Conclusion: The Dar Hygroster filter was found to have the highest humidity and temperature output of all three HMEs, the Humid-Vent filter had a satisfactory humidity output only at low tidal volume flow rate and minute volume settings, whereas the Pall Ultipore BB 100 never achieved a sufficient humidity and temperature output. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study was to build an experimental set-up to assess continuously the humidification, heating and resistance properties of heat-moisture exchangers (HMEs) under clinical conditions.Design: The experimental set-up consists of a patient model, measurement systems and a ventilator.Setting: Surgical ICU, University Hospital of Rotterdam.Materials: A clinically used HME.Measurements and Results: The air flow, pressure in the ventilation circuit, pressure difference over the HME, and partial water vapour pressure and temperature at each side of the HME were measured. The resistance, absolute humidity, humidification efficiency and temperature difference at the patient side of the HME were calculated. Measurements were performed during 24 h. The temperature output, humidity output and lung mechanics of the patient model were similar to values found in mechanically ventilated patients. The measurement system was in agreement with the ISO draft standard and was capable of measuring dynamic variation of water and heat exchange over the range of a clinically used ventilator setting.Conclusion: The experimental set-up described is reliable for evaluating HMEs and can also be used for future clinical evaluation of HMEs. The main advantages of this set-up over those described previously are: (i) measurements of dynamic variations of water and heat exchange; (ii) on-line measurements of expiratory, as well as inspiratory resistance. [ABSTRACT FROM AUTHOR]

Introduction: Closed-loop spinal cord stimulation (CL-SCS) is a recently introduced system that records evoked compound action potentials (ECAPs) from the spinal cord elicited by each stimulation pulse and uses this information to automatically adjust the stimulation strength in real time, known as ECAP-controlled SCS. This innovative system compensates for fluctuations in the distance between the epidural leads and the spinal cord by maintaining the neural response (ECAP) at a predetermined target level. This data collection study was designed to assess the performance of the first CL-SCS system in a real-world setting under normal conditions of use in multiple European centers. The study analyzes and presents clinical outcomes and electrophysiological and device data and compares these findings with those reported in earlier pre-market studies of the same system., Methods: This prospective, multicenter, observational study was conducted in 13 European centers and aimed to gather electrophysiological and device data. The study focused on the real-world application of this system in treating chronic pain affecting the trunk and/or limbs, adhering to standard conditions of use. In addition to collecting and analyzing basic demographic information, the study presents data from the inaugural patient cohort permanently implanted at multiple European centers., Results: A significant decrease in pain intensity was observed for overall back or leg pain scores (verbal numerical rating score [VNRS]) between baseline (mean ± standard error of the mean [SEM]; n = 135; 8.2 ± 0.1), 3 months (n = 93; 2.3 ± 0.2), 6 months (n = 82; 2.5 ± 0.3), and 12 months (n = 76; 2.5 ± 0.3). Comparison of overall pain relief (%) to the AVALON and EVOKE studies showed no significant differences at 3 and 12 months between the real-world data release (RWE; 71.3%; 69.6%) and the AVALON (71.2%; 73.6%) and EVOKE (78.1%; 76.7%) studies. Further investigation was undertaken to objectively characterize the physiological parameters of SCS therapy in this cohort using the metrics of percent time above ECAP threshold (%), dose ratio, and dose accuracy (µV), according to previously described methods. Results showed that a median of 90% (40.7-99.2) of stimuli were above the ECAP threshold, with a dose ratio of 1.3 (1.1-1.4) and dose accuracy of 4.4 µV (0.0-7.1), based on data from 236, 230, and 254 patients, respectively. Thus, across all three metrics, the majority of patients had objective therapy metrics corresponding to the highest levels of pain relief in previously reported studies (usage over threshold > 80%, dose ratio > 1.2, and error < 10 µV)., Conclusions: In conclusion, this study provides valuable insights into the real-world application of the ECAP-controlled CL-SCS system, highlighting its potential for maintaining effective pain relief and objective neurophysiological therapy metrics at levels seen in randomized control trials, and potential for quantifying patient burden associated with SCS system use via patient-device interaction metrics., Clinical Trial Registration: In the Netherlands, the study is duly registered on the International Clinical Trials Registry Platform (Trial NL7889). In Germany, the study is duly registered as NCT05272137 and in the United Kingdom as ISCRTN27710516 and has been reviewed by the ethics committee in both countries., (© 2024. The Author(s).)

Objectives: Approximately 10% of patients who undergo inguinal hernia repair or Pfannenstiel incision develop chronic (> three months) postsurgical inguinal pain (PSIP). If medication or peripheral nerve blocks fail, a neurectomy is the treatment of choice. However, some patients do not respond to this treatment. In such cases, stimulation of the dorsal root ganglion (DRG) appears to significantly reduce chronic PSIP in selected patients., Materials and Methods: In this multicenter, randomized controlled study, DRG stimulation was compared with conventional medical management (CMM) (noninvasive treatments, such as medication, transcutaneous electric neurostimulation, and rehabilitation therapy) in patients with PSIP that was resistant to a neurectomy. Patients were recruited at a tertiary referral center for groin pain (SolviMáx, Eindhoven, The Netherlands) between March 2015 and November 2016. Suitability for implantation was assessed according to the Dutch Neuromodulation Association guidelines. The sponsor discontinued the study early owing to slow enrollment. Of 78 planned patients, 18 were randomized (DRG and CMM groups each had nine patients). Six patients with CMM (67%) crossed over to DRG stimulation at the six-month mark., Results: Fifteen of the 18 patients met the six-month primary end point with a complete data set for a per-protocol analysis. Three patients with DRG stimulation had a negative trial and were lost to follow-up. The average pain reduction was 50% in the DRG stimulation and crossover group (from 6.60 ± 1.24 to 3.28 ± 2.30, p = 0.0029). Conversely, a 13% increase in pain was observed in patients with CMM (from 6.13 ± 2.24 to 6.89 ± 1.24, p = 0.42). Nine patients with DRG stimulation experienced a total of 19 adverse events, such as lead dislocation and pain at the implantation site., Conclusions: DRG stimulation is a promising effective therapy for pain relief in patients with PSIP resistant to conventional treatment modalities; larger studies should confirm this. The frequency of side effects should be a concern in a new study., Clinical Trial Registration: The Clinicaltrials.gov registration number for the study is NCT02349659., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: Persistent back/and or leg pain is a common outcome after spinal surgery (otherwise known as failed back surgery syndrome [FBSS]). Studies have shown that spinal cord stimulation (SCS) at 10 kHz provides effective analgesia in FBSS patients with both back and leg pain symptoms and in those with predominant back pain. This study is the first to evaluate the therapy in FBSS patients with predominant leg pain., Methods: The safety and efficacy of 10 kHz SCS was evaluated in an uncontrolled, open-label, prospective study of FBSS patients with predominant leg pain in the Netherlands. Follow-ups were performed at 1, 3, 6, and 12 months post implantation., Results: Sixty out of 68 patients (88%) experienced sufficient pain relief during a stimulation trial. Of these, 58 proceeded to permanent implantation of a 10 kHz SCS system. After 12 months of treatment, 80% of patients experienced ≥ 50% reduction in baseline leg pain, and a similar proportion (76%) experienced ≥ 50% reduction in baseline back pain. At least two-thirds of patients were also leg pain and back pain remitters (visual analog scale [VAS] ≤ 2.5 cm). The therapy was also associated with a general improvement in patients' quality of life, as measured by secondary outcomes including disability, perception of health improvement, mental well-being, and satisfaction. A positive impact on opioid consumption was also observed., Conclusions: Consistent with previous findings, 10 kHz SCS for the treatment of FBSS patients with predominant radicular symptoms is safe and effective and is associated with improved quality of life., (© 2020 The Authors. Pain Practice published by Wiley Periodicals LLC on behalf of World Institute of Pain.)

Objective: Presently, there is only limited evidence about the cost-effectiveness of peripheral nerve field stimulation (PNFS) and no evidence to date on the cost-effectiveness of PNFS as an add-on therapy to spinal cord stimulation (SCS). In a multicenter randomized controlled trial, PNFS as add-on therapy to SCS demonstrated clinical effectiveness in treating chronic low back pain in failed back surgery syndrome (FBSS) patients. We report here the cost-effectiveness of PNFS as additional therapy., Materials and Methods: Cost-effectiveness analysis was performed from a health-care perspective using the general principles of cost-utility analysis, using empirical data from our multicenter randomized controlled trial on the effectiveness of hybrid SCS + PNFS on low back pain in FBSS patients, who were back pain non-responders to initial SCS-therapy, over a time-horizon of three months. Outcome measures were costs and quality-adjusted life-years (QALYs). Cost and QALYs were integrated using the net monetary benefit (NMB). Differences in costs, effects, and NMB were analyzed using multilevel regression. Uncertainty surrounding the NMB was presented by cost-effectiveness acceptability curves., Results: A total of 52 patients implanted with both SCS and PNFS, randomly assigned to a group with PNFS either activated or inactive, completed the controlled part of the study. With mean total costs for the SCS + active PNFS group of €1813.86 (SD €109.78) versus €1103.64 (SD €123.43) for the SCS + inactive PNFS group at three months, we found an incremental cost-utility ratio of €25.311 per QALY gained and a probability being cost-effective of more than 80% given a willingness to pay for a QALY of about €40.000., Conclusions: From a Dutch national health-care context, when the willingness to pay threshold is up to 60.000 Euros per QALY, PNFS as an add-on therapy to SCS for the treatment of low back pain in FBSS patients has a high probability of being cost-effective., (© 2019 International Neuromodulation Society.)

Objective: To identify variables that influence pain reduction following peripheral nerve field stimulation (PNFS) in order to identify a potential responder profile., Methods: Exploratory univariate and multivariate (random forest) analyses were performed separately on 2 randomized controlled trials and a registry; all included patients with chronic back pain, mainly failed back surgery syndrome. An international expert panel judged the clinical relevance of variables to identify responders by consensus., Results: Variables identified that may help predict PNFS success in patients with back pain include patient and pain characteristics (age, time since onset of pain and spinal surgery, pain medication history, position and size of pain area, pain severity, mixed nociceptive/neuropathic pain, health-related quality of life, depression, functional disability, and leg pain status), implant procedure variables (the number and position of leads, paresthesia coverage, and amount of pain relief during the trial), and programming (number of programs, cathodes, and anodes; pulse rate; pulse width; and percentage of device usage)., Conclusions: While these analyses are exploratory and restricted to a limited sample size, they suggest variables that may play a role in predicting a therapeutic response. These results, however, are informative only and should be cautiously interpreted. Future research to validate the variables in a clinical study is needed., (© 2020 World Institute of Pain.)

Objectives: To investigate the long-term effect of high-dose spinal cord stimulation (HD-SCS) in patients with chronic refractory low back and leg pain due to failed back surgery syndrome (FBSS)., Study Design: Prospective case series; pilot study., Materials and Methods: Patients with chronic low back and leg pain (CBLP) due to failed back surgery syndrome (FBSS) were screened for SCS according to the Dutch Neuromodulation Society guidelines. Patients with a pain score of >50 (on a visual analogue scale from 0 to 100) for both low back and leg pain, were selected for participation in this study. During intraoperative screening one or two electrodes were implanted to ensure adequate paresthesia coverage of the back and leg pain area. During the 14 days trial period patients received two programs: a conventional or low-dose (LD) program with 30 Hz; 390 μsec and a high-dose (HD) program with 420 Hz, 400 μsec. They all started with LD-SCS and changed to HD-SCS after three days. If patients reported more than 50% pain relief with either program a rechargeable neurostimulator was implanted for permanent SCS. The scores for low back pain and leg pain were recorded separately. Other therapy related outcomes that were collected are pain medication use, Quebec back pain disability scale (QBPDS), patient satisfaction, employment status, stimulation settings, and adverse events. We present the 6- and 12-months results. Results are presented as mean ± SD., Results: Thirteen patients, nine females and four males (mean age: 49.7 ± 8.1 years), were included between July 2015 and March 2016. Eleven patients responded to SCS during the trial period and were implanted with a neurostimulator. Most patients preferred HD-SCS over LD-SCS and the overall use of HD-SCS increased over time. At 6 to 12 months follow-up, two patients discontinued the study. In one patient low back pain returned despite optimal stimulation settings. The second patient was neither satisfied with LD nor HD and had the system explanted. VAS Leg pain at baseline was 71.2 ± 33.8 and reduced to 25.7 ± 24.0 at 6 months and 23.4 ± 32.0 at 12 months. VAS Back pain at baseline was 66.7 ± 33.2 and reduced to 36.8 ± 41.6 at 6 months and 26.1 ± 33.2 at 12 months. Pain medication was significantly reduced and QBPDS improved from 59.2 ± 12.2 at baseline to 44.1 ± 13.7 at 12 months. Five patients returned to work and overall patient satisfaction at the end of the study was high., Conclusion: This pilot study shows promising results of offering HD-SCS in addition to LD-SCS for treatment of chronic back and leg pain in patients with failed back surgery syndrome., (© 2019 International Neuromodulation Society.)

Objectives: To compare the effectiveness of peripheral nerve stimulation utilizing a subcutaneous lead implant technique-subcutaneous nerve stimulation (SQS) plus optimized medical management (SQS + OMM arm) vs. optimized medical management alone (OMM arm) in patients with back pain due to failed back surgery syndrome., Patients and Methods: Patients were recruited from 21 centers, in Europe, Israel, and Australia. Eligible patients were randomized (1:1) to SQS + OMM or OMM arms. Those in the SQS arm were implanted with a neurostimulator and up to two subcutaneous percutaneous cylindrical leads in the area of pain. Patients were evaluated pre-randomization and at one, three, six, and nine months post-randomization. The primary endpoint was the proportion of subjects with a ≥50% reduction in back pain intensity ("responder") from baseline to nine months. Secondary outcomes included proportion of responders with a ≥50% reduction in back pain intensity at six months and ≥30% reduction at nine months, and the mean change from baseline in back pain intensity at six and nine months between the two arms., Results: Due to the slow rate of recruitment, the study was terminated early with 116 subjects randomized. A total of 33.9% (19/56, missing: n = 20 [36%]) of subjects in the SQS + OMM arm and 1.7% (1/60, missing: n = 24 [40%]) in the OMM arm were responders at Month 9 (p < 0.0001). Secondary objectives showed a significant difference in favor of SQS + OMM arm., Conclusion: The results indicate that the addition of SQS to OMM is more effective than OMM alone in relieving low back pain at up to nine months., (© 2018 The Authors. Neuromodulation: Technology at the Neural Interface published by Wiley Periodicals, Inc. on behalf of International Neuromodulation Society.)

Objective: Complex regional pain syndrome (CRPS) is characterized by continued pain disproportional to the inciting event, sensory abnormalities, vasomotor and sudomotor disturbances, and motor and trophic changes. Inflammatory involvement has been demonstrated in past CRPS studies resulting in pain, swelling, and warmth. Currently, it is unknown whether spinal cord stimulation (SCS) has immunomodulatory properties. The aim of this study was to determine whether SCS has immunomodulatory properties in CRPS patients., Methods: The primary outcome parameters are cytokines (IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, IL-13, IL-15, IL-17, TNF-α, IFN-γ), chemokines (IP-10 and Eotaxin), and growth factors (VEGF, PDGFbb, and basic FGF) from interstitial fluid of artificial skin blisters before (T0-baseline without SCS) and after SCS therapy (T1-40 Hz standard frequency stimulation and T2-preferred frequency stimulation). Secondary outcome parameters were baseline demographics, CRPS signs, symptoms, and phenotype (inflammatory, vasomotor, dystonia, or neuropathic). Results were analyzed by means of a MANOVA repeated measures design., Results: After SCS, the expression of both pro- and anti-inflammatory cytokines decreased over time in both the CRPS affected extremity and the contralateral extremity. The levels of IP-10, Eotaxin, VEGF, and PDGFbb were also significantly reduced bilaterally. There were no significant changes in IL-6 and TNF-α before and after SCS. The sensory signs, symptoms, and phenotype improved after SCS., Discussion: SCS in CRPS patients attenuates T-cell activation, improves peripheral tissue oxygenation and decreases anti-angiogenetic activity which results in diminished endothelial dysfunction and improved bloodflow. The possible immunomodulatory effects of SCS opens new therapeutic possibilities in diseases with the involvement of the immune system and vasomotor disturbances, and requires further research on these mechanisms of action., (© 2017 International Neuromodulation Society.)

Objective: Suppression of back pain with traditional spinal cord stimulation (SCS) in failed back surgery syndrome patients is often insufficient. The objective of this study was to investigate the efficacy of subcutaneous stimulation (SubQ) as ADD-ON therapy to SCS in treating back pain in failed back surgery syndrome patients., Materials and Methods: Patients with a minimal pain score of 50 on a 100 mm visual analog scale for both leg and back pain were eligible. If pain reduction after trial SCS was ≥50% for the leg but <50% for the back, patients received additional SubQ leads and were randomized in a 1:1 ratio in a study arm with subcutaneous leads switched on (SubQ ADD-ON) and an arm with subcutaneous leads switched off (Control). The primary outcome was the percentage of the patients, at three months since implantation, with ≥50% reduction of back pain., Results: A total of 97 patients were treated with SCS for leg and back pain. Of these, 52 patients were randomized and allocated to the Control group (n = 24) or to the SubQ ADD-ON group (n = 28). The percentage of patients with ≥50% reduction of back pain was significantly higher in the SubQ ADD-ON group (42.9%) compared to the Control group (4.2%). Mean visual analog scale for back pain, at three months, was a statistically significant 28.1 mm lower in the SubQ ADD-ON group compared to the Control group., Conclusion: Subcutaneous stimulation as an ADD-ON therapy to SCS is effective in treating back pain in failed back surgery syndrome patients where SCS is only effective for pain in the leg., (© 2016 International Neuromodulation Society.)

Objective: The objective of this study is to investigate the efficacy of long-term follow-up of subcutaneous stimulation (SubQ) as an additional therapy for patients with failed back surgery syndrome (FBSS) with chronic refractory pain, for whom spinal cord stimulation (SCS) alone was unsuccessful in treating low back pain., Study Design: Prospective case series., Materials and Methods: FBSS patients with leg and/or low back pain whose conventional therapies had failed, received a combination of SCS (8-contact Octad lead, 3877-45 cm, Medtronic, Minneapolis, MN, USA) and/or SubQ (4-contact Quad Plus lead (s), 2888-28 cm, Medtronic). Initially, an Octad lead was placed in the epidural space for SCS for a trial stimulation to assess the suppression of leg and/or low back pain. Where SCS alone was insufficient in treating low back pain, lead(s) were placed superficially in the subcutaneous tissue of the lower back, exactly in the middle of the pain area. A pulse generator (Prime Advanced, 37702, Medtronic) was implanted if the patient reported more than 50% pain relief during the trial period. We investigated the long-term effect of neuromodulation on pain with the visual analog scale (VAS), and disability using the Quebec Pain Disability Scale. The results after 46 months are presented., Results: Eleven patients, five men and six women (age 51 ± 8 years, mean ± SD) were included in the pilot study. In nine cases, SCS was used in combination with SubQ leads. Two patients received only SubQ leads. In one patient, the SCS + SubQ system was removed after nine months and these results were not taken into account for the analysis. Baseline scores for leg (N = 8) and low back pain (N = 10) were VASbl: 59 ± 15 and VASbl: 63 ± 14, respectively. The long-term follow-up period was 46 ± 4 months. SCS significantly reduced leg pain after 12 months (VAS12: 20 ± 11, p12 = 0.001) and 46 months (VAS46: 37 ± 17, p46 = 0.027). Similarly, SubQ significantly reduced back pain after 12 months(VAS12: 33 ± 16, p12 = 0.001) and 46 months (VAS46: 40 ± 21, p46 = 0.013). At 12 months, the Quebec Pain Disability Scale (QPDS) was 49 ± 12 and after 46 months, 53 ± 15. Both at 12 and 46 months, the QPDS values were statistically significantly better (p12 = 0.001, p46 = 0.04) compared with baseline values (QPDSbl: 61 ± 15). In one patient, the pain suppressive effect of SCS/SubQ had disappeared completely over time and the pain scores returned to prestimulation values. In four, patients back pain scores increased over time due to new issues (SI-joint problems, degenerative spine problems, disc problems, and hip pain) unrelated to FBSS and for which SCS/SubQ was not targeted or a reason for implantation at the start of the pilot study., Discussion: This is the first prospective report on the combined use of SCS and SubQ with a follow-up period of four years. These data show that SCS and/or SubQ provide persistent long-term pain relief for leg and back pain in patients with FBSS. One should also take into account that new back/leg pain problems may evolve over time and increase the pain score which impact overall pain treatment., Conclusion: SCS combined with SubQ can be considered an effective long term treatment for low back pain in patients with FBSS for whom SCS alone is insufficient in alleviating their pain symptoms., (© 2015 International Neuromodulation Society.)

Background: Percutaneous cervical nucleoplasty (PCN) is a safe and effective treatment in symptomatic patients with contained cervical herniated disks. It provides simple and efficient disk decompression, using a controlled and highly localized ablation, but evidence regarding long-term efficacy is limited. We conducted a retrospective study to investigate the long-term efficacy and safety of PCN, and the influence of ideal selection settings., Methods: A total of 27 patients treated with PCN fulfilling ideal selection criteria (Group A) were studied and compared to 42 patients not meeting these criteria (Group B). Outcomes were assessed using the Visual Analogue Scale (VAS) and a four-level Likert item for perceived pain and satisfaction, the Neck Disability Index (NDI), and the Short Form 36 (SF-36). Additional relevant outcomes were retrieved from medical records., Results: The postoperative mean VAS pain for Group A was 29.9 (SD ± 32.6) at a mean follow-up of 24 months (range: 2-45). Only 10% of these patients reported mild transient adverse events. There was a trend, but no difference between both groups in pain scores; however, treatment satisfaction was higher for Group A (74.1 ± 27.2-55.5 ± 31.4, P = 0.02). Group A also reported better physical functioning based on the Physical Component Summary (43.6 ± 10.6-37.3 ± 12.0, P = 0.03) and showed a larger proportion of patients no longer using any medication postoperatively (63-26%, P = 0.01)., Conclusion: These results show long-term effectiveness and safety of PCN in patients with a one-level contained cervical herniated disk, and the reliance of selecting patients meeting ideal criteria for successful PCN., (© 2012 The Authors Pain Practice © 2012 World Institute of Pain.)

Objective: The objective of this study was to demonstrate the efficacy of subcutaneous stimulation (SubQ) as an additional therapy in patients with failed back surgery syndrome (FBSS) with chronic refractory pain, for whom spinal cord stimulation (SCS) was unsuccessful in treating low back pain., Study Design: Case series., Materials and Methods: FBSS patients with chronic limb and/or low back pain whose conventional therapies had failed received a combination of SCS (8-contact Octad lead) and/or SubQ (4-contact Quad Plus lead(s)). Initially leads were placed in the epidural space for SCS for a trial stimulation to assess response to suppression of limb and low back pain. Where SCS alone was insufficient in treating lower back pain, leads were placed superficially in the subcutaneous tissue of the lower back, directly in the middle of the pain area. A pulse generator was implanted if patients reported more than 50% pain relief during the trial period. Pain intensity for limb and lower back pain was scored separately, using visual analog scale (VAS). Pain and Quebec Back Pain Disability Scale (QBPDS) after 12-month treatment were compared with pain and QBPDS at baseline., Results: Eleven FBSS patients, five male and six female (age: 51 ± 8 years; mean ± SD), in whom SCS alone was insufficient in treating lower back pain, were included. In nine cases, SubQ was used in combination with SCS to treat chronic lower back and lower extremity pain. In two cases only SubQ was used to treat lower back pain. SCS significantly reduced limb pain after 12 months (VAS(bl) : 62 ± 14 vs. VAS(12m) : 20 ± 11; p= 0.001, N= 8). SubQ stimulation significantly reduced low back pain after 12 months (VAS(bl) : 62 ± 13.0 vs. VAS(12m) : 32 ± 16; p= 0.0002, N= 10). Overall pain medication was reduced by more than 70%. QBPDS improved from 61 ± 15 to 49 ± 12 (p= 0.046, N= 10). Furthermore, we observed that two patients returned to work., Conclusion: SubQ may be an effective additional treatment for chronic low back pain in patients with FBSS for whom SCS alone is insufficient in alleviating their pain symptoms., (© 2011 International Neuromodulation Society.)

Symptomatic thoracic disc herniation is an uncommon condition and early surgical approaches were associated with significant morbidity and even mortality. We are the first to describe the technique of percutaneous thoracic nucleoplasty in three patients with severe radicular pain due to thoracic disc herniation. Two of the patients experienced more than 75% pain relief and one patient experienced more than 50% pain relief. Post-procedural pain relief was maintained up to an average of 10 months after nucleoplasty. One patient with preoperative neurological signs improved postoperatively. There were no reported complications in all three patients. In view of the reduced morbidity and shorter operating time, thoracic intervertebral disc nucleoplasty can be considered in patients with pain due to thoracic disc herniation, with no calcification of the herniated disc, and in patients who may be otherwise be unfit for conventional surgery.

There are few reports on anaesthesia for patients with Eisenmenger's syndrome requiring non-cardiac surgery and none of the use of xenon. We describe the use of xenon with a closed-circuit system in a patient with Eisenmenger's syndrome having a laparoscopic cholecystectomy.

Objectives: a) To determine the validity of a new method to analyze indicator gas washout tests on mechanically ventilated patients. This method takes into account the difference between the end-expiratory gas fraction and the mean gas fraction in the lung and provides the end-expiratory lung volume and a new index of ventilation inhomogeneity called volumes regression index. b) To determine the validity of this index as a predictor of chronic obstructive pulmonary disease. c) To compare this index with the moment ratio index and Becklake index., Design: Prospective study of diagnostic test. Criterium standards: Closed-circuit indicator gas dilution technique and Tiffeneau index., Setting: Surgical intensive care unit of a university hospital., Patients: A total of 38 mechanically ventilated postoperative patients, divided into two groups: the obstructive group (n = 21) and the nonobstructive group (n = 17), based on their preoperative lung function., Interventions: None., Measurements and Main Results: a) The mean coefficient of variation of all lung volume measurements in a group of nine healthy volunteers was 5%, and the difference between this technique and the closed-circuit helium dilution measurements was -2 +/- 5%. In patients, the mean coefficient of variation of the lung volume measurements was 3.5%. The volumes regression index was measured as 0.02 +/- 0.04 in a dummy lung, 0.37 +/- 0.08 in the healthy volunteers, 0.64 +/- 0.23 in the nonobstructive patients, and 1.1 +/- 0.3 in the obstructive patients. The volumes regression index provided a better correlation (r2 = .46) with preoperatively determined Tiffeneau index than the Becklake index (r2 = .11) or the moment ratio index (r2 = .18)., Conclusion: The proposed technique provides a means for accurate measurement of the end-expiratory lung volume and the amount of ventilation inhomogeneity in mechanically ventilated intensive care unit patients.