Automated Pain Spots Recognition Algorithm Provided by a Web Service-Based Platform: Instrument Validation Study.

Background: Understanding the causes and mechanisms underlying musculoskeletal pain is crucial for developing effective treatments and improving patient outcomes. Self-report measures, such as the Pain Drawing Scale, involve individuals rating their level of pain on a scale. In this technique, individuals color the area where they experience pain, and the resulting picture is rated based on the depicted pain intensity. Analyzing pain drawings (PDs) typically involves measuring the size of the pain region. There are several studies focusing on assessing the clinical use of PDs, and now, with the introduction of digital PDs, the usability and reliability of these platforms need validation. Comparative studies between traditional and digital PDs have shown good agreement and reliability. The evolution of PD acquisition over the last 2 decades mirrors the commercialization of digital technologies. However, the pen-on-paper approach seems to be more accepted by patients, but there is currently no standardized method for scanning PDs. Objective: The objective of this study was to evaluate the accuracy of PD analysis performed by a web platform using various digital scanners. The primary goal was to demonstrate that simple and affordable mobile devices can be used to acquire PDs without losing important information. Methods: Two sets of PDs were generated: one with the addition of 216 colored circles and another composed of various red shapes distributed randomly on a frontal view body chart of an adult male. These drawings were then printed in color on A4 sheets, including QR codes at the corners in order to allow automatic alignment, and subsequently scanned using different devices and apps. The scanners used were flatbed scanners of different sizes and prices (professional, portable flatbed, and home printer or scanner), smartphones with varying price ranges, and 6 virtual scanner apps. The acquisitions were made under normal light conditions by the same operator. Results: High-saturation colors, such as red, cyan, magenta, and yellow, were accurately identified by all devices. The percentage error for small, medium, and large pain spots was consistently below 20% for all devices, with smaller values associated with larger areas. In addition, a significant negative correlation was observed between the percentage of error and spot size (R=-0.237; P=.04). The proposed platform proved to be robust and reliable for acquiring paper PDs via a wide range of scanning devices. Conclusions: This study demonstrates that a web platform can accurately analyze PDs acquired through various digital scanners. The findings support the use of simple and cost-effective mobile devices for PD acquisition without compromising the quality of data. Standardizing the scanning process using the proposed platform can contribute to more efficient and consistent PD analysis in clinical and research settings.

Assessment of Bone Mineral Density Over 1 Year in a Cross-Sectional Cohort of Migraine Patients Receiving Anti-CGRP Monoclonal Antibodies.

BACKGROUND: Calcitonin gene-related peptide (CGRP), implicated in migraine pain, also possesses bone anabolic properties, which leads to the possibility that monoclonal antibodies targeting CGRP (anti-CGRPs) might increase the risk of bone density abnormalities. OBJECTIVE: The objective of this study was to explore bone mineral density abnormalities in a cohort of migraine patients treated with anti-CGRPs. METHODS: This was a single-center, cross-sectional, cohort study including migraine patients who underwent a densitometry assessment during anti-CGRP treatment. We assessed the frequency of osteopenia or osteoporosis (OSTEO+ status), defined as a bone mineral density T-score of -1 to -2.5, and <-2.5 standard deviations from the young female adult mean, respectively. Additionally, the association of OSTEO+ status with anti-CGRP treatment duration and primary osteoporosis' risk factors was investigated using logistic regression models. RESULTS: Data from 51 patients (43 female, mean age 46 ± 13.9 years) were evaluated. The mean duration of anti-CGRP treatment was 15.7 (±11.8) months. Twenty-seven patients (53%) were OSTEO+ (n = 22 osteopenia; n = 5 osteoporosis). In the final model, menopause [odds ratio 11.641 (95% confidence interval 1.486-91.197), p = 0.019] and anti-seizure drug use [odds ratio 12.825 (95% confidence interval 1.162-141.569), p = 0.037] were associated with OSTEO+ status. CONCLUSIONS: In our cohort of migraine patients, no evidence of an association between anti-CGRP treatment duration and an increasing risk of bone mineral density abnormalities was found. However, these findings are preliminary and necessitate further longitudinal research with larger cohorts and extended follow-up to be validated.

Reliability of the Pen-on-Paper Pain Drawing Analysis Using Different Scanning Procedures.

INTRODUCTION: Pen-on-paper pain drawing are an easily administered self-reported measure that enables patients to report the spatial distribution of their pain. The digitalization of pain drawings has facilitated the extraction of quantitative metrics, such as pain extent and location. This study aimed to assess the reliability of pen-on-paper pain drawing analysis conducted by an automated pain-spot recognition algorithm using various scanning procedures. METHODS: One hundred pain drawings, completed by patients experiencing somatic pain, were repeatedly scanned using diverse technologies and devices. Seven datasets were created, enabling reliability assessments including inter-device, inter-scanner, inter-mobile, inter-software, intra- and inter-operator. Subsequently, the automated pain-spot recognition algorithm estimated pain extent and location values for each digitized pain drawing. The relative reliability of pain extent analysis was determined using the intraclass correlation coefficient, while absolute reliability was evaluated through the standard error of measurement and minimum detectable change. The reliability of pain location analysis was computed using the Jaccard similarity index. RESULTS: The reliability analysis of pain extent consistently yielded intraclass correlation coefficient values above 0.90 for all scanning procedures, with standard error of measurement ranging from 0.03% to 0.13% and minimum detectable change from 0.08% to 0.38%. The mean Jaccard index scores across all dataset comparisons exceeded 0.90. CONCLUSIONS: The analysis of pen-on-paper pain drawings demonstrated excellent reliability, suggesting that the automated pain-spot recognition algorithm is unaffected by scanning procedures. These findings support the algorithm's applicability in both research and clinical practice.

Efficacy and safety of the implantable, magnetic resonance imaging-compatible StimRouter neuromodulation system in the treatment of refractory lower urinary tract symptoms in multiple sclerosis patients.

BACKGROUND AND PURPOSE: Lower urinary tract symptoms (LUTS) significantly affect quality of life (QoL) of multiple sclerosis (MS) patients, and pharmacotherapy has limited efficacy. We investigated efficacy and safety of the implantable StimRouter neuromodulation system for treating refractory LUTS in MS. METHODS: This prospective, single-center, clinical trial was conducted at the Multiple Sclerosis Center of Lugano, Switzerland, involving MS patients treated with self-administered percutaneous tibial nerve stimulation delivered by StimRouter over 24 weeks. Changes in video-urodynamic parameters as well as LUTS severity were measured by Overactive Bladder Questionnaire (OAB-q), QoL using the Multiple Sclerosis Quality of Life (MSQoL-54), and treatment satisfaction using a 1-10 visual analogue scale. Adverse events were also recorded. RESULTS: Of 23 MS patients recruited, six had neurogenic detrusor overactivity (NDO), five had detrusor sphincter dyssynergia (DSD), and 12 had both NDO and DSD. Of patients with NDO, median bladder volume at first uninhibited contraction significantly increased from baseline to week 24 (median = 136 mL, interquartile range [IQR] = 101-244 mL vs. 343 mL, IQR = 237-391 mL; ß = 138.2, p = 0.001). No significant changes of urodynamic parameters were found in patients with DSD. OAB-q symptom scores progressively decreased, and OAB-q quality of life scores increased (ß = -0.50, p < 0.001 and ß = 0.47, p < 0.001, respectively), whereas MSQoL-54 scores did not significantly change (ß = 0.24, p = 0.084) in the overall population. Treatment satisfaction was overall high (median = 8, IQR = 6-9). No serious adverse events were recorded. CONCLUSIONS: StimRouter represents a minimally invasive, magnetic resonance imaging-compatible, self-administered neuromodulation device leading to objective and subjective improvements of OAB symptoms and related QoL in MS patients with refractory LUTS.

Spinal cord stimulation in severe pharmacoresistant restless legs syndrome-two case reports.

Restless legs syndrome is a prevalent, sleep-related sensorimotor disorder with relevant impact on the patients' quality of life. For patients suffering from severe, pharmacoresistant restless legs syndrome, few therapeutic options remain to alleviate symptoms. In this case series, two patients with severe, pharmacoresistant restless legs syndrome were treated with epidural spinal cord stimulation and repeatedly assessed with polysomnography, including sleep structure and periodic limb movements as objective biomarkers not subject to placebo effects, during a 6-month follow-up period. One of the patients experienced excellent short- and long-term efficacy on subjective symptom severity (International RLS Study group rating scale 1 vs. 34 points at 3 months) and objective sleep parameters such as sleep architecture and periodic limb movements during sleep, while the second patient only reported short-term benefits from spinal cord stimulation. Ultimately, both patients opted for removal of the device for inefficacy. Based on the complex pathophysiology of restless legs syndrome and presumed mechanism of action of spinal cord stimulation in chronic pain disorders, we provide a detailed hypothesis on the possible modulating effect of spinal cord stimulation on the key symptoms of restless legs syndrome. Apart from describing a new therapeutic option for pharmacoresistant restless legs syndrome, our findings might also provide further insights into the pathophysiology of the syndrome.

"Can't Intubate Can't Oxygenate" Situation in an Elective Patient in Suspected Sarcoidosis: A Case Report.

Anaesthetists and pulmonologists are well trained to follow the "can't intubate, can't oxygenate" (CICO) protocol but the procedure is rarely practised. This case report concerns an elective patient scheduled for endobronchial ultrasound bronchoscopy (EBUS) because of suspected sarcoidosis. Based on known medical history, anaesthesia for EBUS procedure was initiated with a laryngeal mask. The airway turned out to be difficult and the patient was not ventilable despite several efforts including curarization and orotracheal intubation. Rapid desaturation imposed to apply the CICO protocol with emergency cricothyroidotomy as extreme measure but also failed. 6-handed face mask ventilation was continued. Eventually, introduction of a microlaryngeal tube of the 3rd generation laryngeal mask, placed on the fibrescope, allowed endotracheal intubation. The patient fell into pulseless electrical activity, and the CICO protocol was started. Immediate cardiopulmonary resuscitation totally recovered vital functions. In the post-operative follow-up, no temporary or permanent cardiological and neurological sequels were found, but new medical history such as inconstant use of C-PAP (Continuous Positive Airway Pressure) and a significant weight gain since the last notable difficult intubation were uncovered, which explained the patient's compromised airways. Had this information been available prior to the scheduled operation, it would have indicated awake intubation with a local anaesthesia of the oropharynx and appropriate sedation of the patient. LEARNING POINTS: The CICO protocol was effective to manage an unanticipated difficult airway. The patient was resuscitated with the use of a microlaryngeal endotracheal tube of the 3rd generation laryngeal mask, placed on the fibrescope.The patient's previous and current medical condition is of vital importance for the pre-operative anaesthetic assessment.Specific questioning during the pre-operative anaesthetic interview could detect events that seem to be insignificant to the patient but are significant for a diagnostic intervention in a new situation.

Long-term safety of spinal cord stimulation systems in a prospective, global registry of patients with chronic pain.

Aim: The availability of long-term (>2 years) safety outcomes of spinal cord stimulation (SCS) remains limited. We evaluated safety in a global SCS registry for chronic pain. Methods: Participants were prospectively enrolled globally at 79 implanting centers and followed out to 3 years after device implantation. Results: Of 1881 participants enrolled, 1289 received a permanent SCS implant (1776 completed trial). The annualized rate of device explant was 3.5% (all causes), and 1.1% due to inadequate pain relief. Total incidence of device explantation >3 years was 7.6% (n = 98). Of these, 32 subjects (2.5%) indicated inadequate pain relief as cause for removal. Implant site infection (11 events) was the most common device-related serious adverse event (<1%). Conclusion: This prospective, global, real-world study demonstrates a high-level of safety for SCS with low rate of explant/serious adverse events. Clinical Trial Registration: NCT01719055 (ClinicalTrials.gov).

Dorsal Root Ganglion Stimulation in Chronic Painful Polyneuropathy: A Potential Modulator for Small Nerve Fiber Regeneration.

OBJECTIVES: Neuromodulatory treatments like spinal cord stimulation and dorsal root ganglion stimulation (DRGS) have emerged as effective treatments to relieve pain in painful polyneuropathy. Animal studies have demonstrated that neurostimulation can enhance nerve regeneration. This study aimed to investigate if DRGS may impact intraepidermal nerve fiber regeneration and sensory nerve function. MATERIALS AND METHODS: Nine patients with chronic, intractable painful polyneuropathy were recruited. Intraepidermal nerve fiber density (IENFD) quantification in 3 mm punch skin biopsy was performed 1 month before DRGS (placed at the level of the L5 and S1 dorsal root ganglion) and after 12- and 24-month follow-up. Quantitative sensory testing, nerve conduction studies, and a clinical scale score were also performed at the same time points. RESULTS: In 7 of 9 patients, DRGS was successful (defined as a reduction of ≥ 50% in daytime and/or night-time pain intensity), allowing a definitive implantable pulse generator implantation. The median baseline IENFD among these 7 patients was 1.6 fibers/mm (first and third quartile: 1.2; 4.3) and increased to 2.6 fibers/mm (2.5; 2.9) and 1.9 fibers/mm (1.6; 2.4) at 1- and 2-years follow-up, respectively. These changes were not statistically significant (p = 1.000 and 0.375). Sensory nerve tests did not show substantial changes. CONCLUSIONS: Although not significant, the results of this study showed that in most of the patients with implants, there was a slight increase of the IENFD at the 1- and 2-year follow-up. Larger-scale clinical trials are warranted to explore the possible role of DRGS in reversing the progressive neurodegeneration over time. CLINICAL TRIAL REGISTRATION: The Clinicaltrials.gov registration number for the study is NCT02435004; Swiss National Clinical Trials Portal: SNCTP000001376.

Real-world outcomes of single-stage spinal cord stimulation in chronic pain patients: A multicentre, European case series.

Background: Spinal cord stimulation (SCS) is effective in treating chronic neuropathic pain. A screening trial is typically conducted prior to implantation to evaluate whether a patient is a good candidate for SCS. However, the need for a screening trial has been debated. We evaluated real-world clinical outcomes in patients who underwent a single-stage procedure to receive SCS therapy (i.e., no screening trial period) (SS-SCS). Methods: This observational, multicentre, real-world consecutive case series evaluated SS-SCS chronic pain patients. Pain and other functional outcomes were collected as part of standard care by site personnel with no sponsor involvement. Assessments included Numerical rating scale (NRS), Percent Pain Relief (PPR) and EQ-5D-5L (EuroQol 5 Dimensions-5L), recorded prior to SCS and following implantation. Results: A total of 171 chronic pain patients (mean age: 59.4; 53.2% females) underwent a single-stage procedure (mean last follow-up, 408 days) and were included in the analysis. A 5.0 â€‹± â€‹2.1-point improvement in overall pain was reported at 3 months and sustained until the last follow-up post-implantation (p â€‹< â€‹0.0001). At last follow-up, 50.3% (86/171) of patients reported an NRS pain score ≤3. Additionally, quality of life also improved (46.1-point change, from 70.2 to 25) at the last follow-up, based on EQ-5D-5L scores. Conclusions: In routine clinical practice, SS-SCS can provide significant long-term pain relief and improve quality of life in chronic pain patients. Our results suggest that effective long-term outcomes and success may be achieved without a trial period prior to permanent implantation of an SCS system.

Efficacy of the Gelstix nucleus augmentation device for the treatment of chronic discogenic low back pain: protocol for a randomised, sham-controlled, double-blind, multicentre trial.

INTRODUCTION: Discogenic pain is the cause of pain in 26%-40% of patients with for low back pain. Consensus about treatment of chronic discogenic low back pain is lacking and most treatment alternatives are supported by limited evidence. The percutaneous implantation of hydrogels into the nucleus pulposus represents a promising regenerative intradiscal therapy. The hydrogel 'GelStix' is composed primarily of hydrolyzed polyacrylonitrile and acts as a reservoir of hydration, producing increased pressure and improved pH balance, potentially leading to disc preservation. We hypothesise that treatment with GelStix will lead to greater reduction in pain intensity at 6 months post-treatment compared with patients receiving sham treatment. METHODS AND ANALYSIS: This is a parallel group, randomised sham-controlled double-blind, multicentre trial to assess whether the GelStix device is superior to sham in reducing pain intensity in patients with chronic discogenic low back pain. The study will be conducted in two regional hospitals in Europe. Seventy-two participants will be randomised in a 1:1 ratio. The primary outcome will be the change in pain intensity between preoperative baseline and at 6 months postintervention. Secondary outcomes were disability, quality of life, the patient's global impression of change scale, the use of pain medication and the disc degeneration process assessed by means of MRI. For change in pain intensity, disability, health-related quality of life and disc height, mean values will be compared between groups using linear regression analysis, adjusted for treatment centre. ETHICS AND DISSEMINATION: Ethics approval was obtained from the Ethics Committee of the Canton Ticino, Switzerland (CE2982) and by the Medical Ethical Committee Arnhem-Nijmegen, the Netherlands (2016-2944). All patients that agree to participate will be asked to sign an informed consent form. Results will be disseminated through international publications in peer-reviewed journals, in addition to international conference presentations. TRIAL REGISTRATION NUMBER: NCT02763956. PROTOCOL VERSION: 7.1, 18 November 2020.

Real-World Outcomes Using a Spinal Cord Stimulation Device Capable of Combination Therapy for Chronic Pain: A European, Multicenter Experience.

Given the differing mechanisms thought to underlie therapeutic sub- and supra-perception-based neurostimulative modalities, Spinal Cord Stimulation (SCS) systems designed for combined delivery of these approaches may help improve analgesic outcomes and quality of life, and reduce treatment failures. This multicenter, observational case-series evaluated 188 patients with chronic back and/or leg pain implanted with an SCS device capable of sequential or simultaneous delivery of sub-perception and supra-perception stimulation programming (i.e., combination therapy) at 16 in Europe. Following implantation, patients were provided with an array of advanced supra-perception programs (e.g., paresthesia-based SCS using multiple independent current sources), and a custom set of sub-perception programs optimized with specific waveforms and/or field shapes. A mean overall pain score of 7.9 ± 1.7 (Standard Deviation (SD)) was reported pre-trial (Baseline). Overall pain was reduced by 4.4 ± 2.8 points (NRS) at 3-months (n = 117) and at 12 months post-implant (n = 90), respectively (p < 0.0001). Substantial quality-of-life (EQ-5D-5L) improvement as assessed at last follow-up was also observed (n = 60). These results suggest that an implanted SCS device capable of combination therapy, while also enabled with patient-specific waveform optimization and stimulation field targeting capabilities, can enable highly effective pain relief and improve quality of life in patients suffering with chronic pain.

Effectiveness of percutaneous posterior tibial nerve stimulation for the management of bowel dysfunction in multiple sclerosis patients.

BACKGROUND: Neurogenic bowel dysfunctions (NBDs) in the form of both fecal incontinence (FI) and functional constipation (FC) are frequent in multiple sclerosis (MS) patients and significantly affect their quality of life. Therapeutic options are limited. OBJECTIVE: To investigate effectiveness of percutaneous posterior tibial nerve stimulation (PTNS) in MS patients suffering from FI and FC. METHODS: Prevalence and severity of FI and FC were prospectively collected among MS patients undergoing 12 weeks of PTNS for neurogenic bladder. The Cleveland Clinic Fecal Incontinence Score (CCFIS) and the Rome III criteria were used to define FI and FC, respectively. Subjective treatment satisfaction was estimated using the Benefit Satisfaction and Willingness to Continue (BSWC) questionnaire. RESULTS: A total of 60 patients undergoing PTNS suffered from NBDs (25 FI+/FC+, 5 FI+/FC-, 30 FI-/FC+). Median CCFIS decreased after PTNS from 12.0 (11.0-13.0) to 8.5 (7.0-11.0, p < 0.001), with particular improvements in liquid and flatal incontinence, pads' need, and lifestyle restrictions. Seven patients became FC free after PTNS and no patients developed FC during the study (p = 0.023). More than 50% of the patients were satisfied and willing to continue PTNS at study end. CONCLUSION: PTNS represents a valid minimally invasive alternative treatment for MS patients suffering from NBDs.

Dorsal Root Ganglion Stimulation for the Management of Intractable Painful Polyneuropathy: A Prospective Pilot Study.

OBJECTIVES: Dorsal root ganglion stimulation (DRGS) is a promising neurostimulation modality in the treatment of painful polyneuropathy. The aim of this prospective pilot study was to investigate the effect of DRGS on pain intensity in patients with intractable painful polyneuropathy. MATERIALS AND METHODS: Nine patients with chronic, intractable painful polyneuropathy in the lower limbs were recruited. In each subject, between two and four DRGS leads were placed at the level of the L5 and S1 dorsal root ganglion. If trial stimulation was successful, a definitive implantable pulse generator (IPG) was implanted. Pain intensity was scored using an 11-point numeric rating scale (NRS) and reported as median and interquartile range (IQR), and compared to baseline values using the Wilcoxon signed-rank test. Additionally, patients' global impression of change (PGIC), pain extent, presence of neuropathic pain, physical functioning, quality of life, and mood were assessed. RESULTS: Eight out of nine patients had a successful trial phase, of which seven received an IPG. Daytime pain decreased from a median (IQR) NRS score of 7.0 (5.9-8.3) to 2.0 (1.0-3.5) and 3.0 (1.6-4.9) in the first week and at six months after implantation, respectively. Similar effects were observed for night time and peak pain scores. CONCLUSIONS: The results of this study suggest that DRGS significantly reduces both pain intensity and PGIC in patients with intractable painful polyneuropathy in the lower extremities. Large-scale clinical trials are needed to prove the efficacy of DRGS in intractable painful polyneuropathy.

Cervical Radiculopathy Caused by a Vertebral Artery Loop: Is a Focused Fluoroscopic-Guided Cervical Epidural Steroid Injection a Possible Treatment Modality?

We describe a case of a patient suffering with cervical radiculopathy due to vertebral artery loop with nerve root compression, treated with an epidural steroid injection. A 37-year-old man presented with a 2-year history of right-sided radicular pain along the C7 dermatome. Imaging showed a right-sided loop of the vertebral artery at the V1-V2 transition with contact on the C7 nerve root. The pain was resistant to conservative treatment, and the decision was made to perform a focused fluoroscopy-guided translaminar epidural steroid injection near the C7 nerve root. The procedure was uneventful, and the symptoms resolved completely after the procedure. Targeted epidural steroid injection might be a useful and safe diagnostic and therapeutic approach in patients affected by cervical radiculopathy due to a VA loop. To our knowledge, this is the first case of a VA loop associated with cervical radiculopathy treated with this technique.

Corticospinal Control of Human Locomotion as a New Determinant of Age-Related Sarcopenia: An Exploratory Study.

Sarcopenia is a muscle disease listed within the ICD-10 classification. Several operational definitions have been created for sarcopenia screening; however, an international consensus is lacking. The Centers for Disease Control and Prevention have recently recognized that sarcopenia detection requires improved diagnosis and screening measures. Mounting evidence hints towards changes in the corticospinal communication system where corticomuscular coherence (CMC) reflects an effective mechanism of corticospinal interaction. CMC can be assessed during locomotion by means of simultaneously measuring Electroencephalography (EEG) and Electromyography (EMG). The aim of this study was to perform sarcopenia screening in community-dwelling older adults and explore the possibility of using CMC assessed during gait to discriminate between sarcopenic and non-sarcopenic older adults. Receiver Operating Characteristic (ROC) curves showed high sensitivity, precision and accuracy of CMC assessed from EEG Cz sensor and EMG sensors located over Musculus Vastus Medialis [Cz-VM; AUC (95.0%CI): 0.98 (0.92-1.04), sensitivity: 1.00, 1-specificity: 0.89, p < 0.001] and with Musculus Biceps Femoris [Cz-BF; AUC (95.0%CI): 0.86 (0.68-1.03), sensitivity: 1.00, 1-specificity: 0.70, p < 0.001]. These muscles showed significant differences with large magnitude of effect between sarcopenic and non-sarcopenic older adults [Hedge's g (95.0%CI): 2.2 (1.3-3.1), p = 0.005 and Hedge's g (95.0%CI): 1.5 (0.7-2.2), p = 0.010; respectively]. The novelty of this exploratory investigation is the hint toward a novel possible determinant of age-related sarcopenia, derived from corticospinal control of locomotion and shown by the observed large differences in CMC when sarcopenic and non-sarcopenic older adults are compared. This, in turn, might represent in future a potential treatment target to counteract sarcopenia as well as a parameter to monitor the progression of the disease and/or the potential recovery following other treatment interventions.

Dorsal Root Ganglion Stimulation in Experimental Painful Diabetic Polyneuropathy: Delayed Wash-Out of Pain Relief After Low-Frequency (1Hz) Stimulation.

OBJECTIVE: Up until now there is little data about the pain relieving effect of different frequency settings in DRGS. The aim of this study was to compare the pain relieving effect of DRGS at low-, mid-, and high-frequencies and Sham-DRGS in an animal model of painful diabetic neuropathy (PDPN). MATERIAL AND METHODS: Diabetes mellitus was induced by an intraperitoneal injection of streptozotocin in 8-week-old female Sprague-Dawley rats (n = 24; glucose ≥15 mmol/L: n = 20; mechanical hypersensitivity: n = 15). Five weeks later, a DRGS device was implanted at the L5 DRG. Ten animals were included for stimulation, alternating 30 minutes of low (1 Hz)-, mid (20 Hz)-, and high (1000 Hz)-frequencies and Sham-DRGS during four days, with a pulse width of 0.2 msec (average amplitude: 0.19 ± 0.01 mA), using a randomized cross-over design. The effect on mechanical hypersensitivity of the hind paw to von Frey filaments was evaluated. RESULTS: All DRGS frequencies resulted in a complete reversal of mechanical hypersensitivity and "a clinically relevant reduction" was achieved in 70-80% of animals. No significant differences in maximal pain relieving effect were found between the different frequency treatments (p = 0.24). Animals stimulated at 1000 and 20 Hz returned to baseline mechanical hypersensitivity values 15 and 30 min after stimulation cessation, respectively, while animals stimulated at 1 Hz did not. CONCLUSIONS: These results show that DRGS is equally effective when applied at low-, mid-, and high-frequency in an animal model of PDPN. However, low-frequency-(1 Hz)-DRGS resulted in a delayed wash-out effect, which suggests that this is the most optimal frequency for pain therapy in PDPN as compared to mid- and high-frequency.

Mechanism of dorsal root ganglion stimulation for pain relief in painful diabetic polyneuropathy is not dependent on GABA release in the dorsal horn of the spinal cord.

AIMS: It is hypothesized that dorsal root ganglion stimulation (DRGS), sharing some of the mechanisms of traditional spinal cord stimulation (SCS) of the dorsal columns, induces γ-aminobutyric acid (GABA) release from interneurons in the spinal dorsal horn. METHODS: We used quantitative immunohistochemical analysis in order to investigate the effect of DRGS on intensity of intracellular GABA-staining levels in the L4-L6 spinal dorsal horn of painful diabetic polyneuropathy (PDPN) animals. To establish the maximal pain relieving effect, we tested for mechanical hypersensitivity to von Frey filaments and animals received 30 minutes of DRGS at day 3 after implantation of the electrode. One day later, 4 Sham-DRGS animals and four responders-to-DRGS received again 30 minutes of DRGS and were perfused at the peak of DRGS-induced pain relief. RESULTS: No significant difference in GABA-immunoreactivity was observed between DRGS and Sham-DRGS in lamina 1-3 of the spinal levels L4-6 neither ipsilaterally nor contralaterally. CONCLUSIONS: Dorsal root ganglion stimulation does not induce GABA release from the spinal dorsal horn cells, suggesting that the mechanisms underlying DRGS in pain relief are different from those of conventional SCS. The modulation of a GABA-mediated "Gate Control" in the DRG itself, functioning as a prime Gate of nociception, is suggested and discussed.

Myofascial pain syndrome and trigger points: evaluation and treatment in patients with musculoskeletal pain.

PURPOSE OF REVIEW: Myofascial pain syndrome is a chronic pain condition characterized by the presence of myofascial trigger point, a hyperirritable painful spot involving a limited number of muscle fibers. The literature suggest that myofascial trigger points should be considered peripheral pain generators and this critical review will summarize recent findings concerning the clinical evaluation and the treatment of myofascial trigger points. RECENT FINDINGS: The clinical features of myofascial trigger points and their contribution to the patient pain and disability have been detailed in several recent studies, which support the clinical relevance of the condition. Recent studies reported that manual palpation to identify MTrPs has good reliability, although some limitations are intrinsic to the diagnostic criteria. During the last decade, a plethora of treatments have been proposed and positive effects on pain and function demonstrated. SUMMARY: The myofascial trigger point phenomenon has good face validity and is clinically relevant. Clinicians are encouraged to consider the contribution of myofascial trigger points to the patient's pain and disability through a careful medical history and a specific manual examination. Patients with myofascial trigger points will benefit from a multimodal treatment plan including dry needling and manual therapy techniques. Internal and external validity of research within the field must be improved.

Refill Port Identification of Intrathecal Drug Delivery System Devices With a Raised Fill Port.

OBJECTIVES: The aim of this study was to assess the accuracy of the manual identification of the reservoir fill port (RFP) for refill of intrathecal drug delivery systems (IDDSs) with a raised RFP on the pump surface (raised-RFP-IDDSs), and compare this to previously reported data of patients with IDDSs with a recessed RFP (recessed-RFP-IDDSs). METHODS: Nineteen patients underwent 2 IDDS refills for the treatment of noncancer pain or spasticity. The primary endpoint of this prospective observational study was the deviation between the needle insertion point and the RFP center, quantified by fluoroscopic visualization. A distance surpassing that between the center and the margin of the RFP of 4 mm was considered a clinically relevant deviation. The results were compared with previously reported data of a patient cohort with recessed-RFP-IDDSs, and the differences were tested using Student's t-test. RESULTS: The mean deviation from the RFP center was 4.9 mm (standard deviation = 3.7). The RFP identification accuracy deviated more than the clinically relevant difference in 17 out of 35 instances (48.6%). The number of attempts and median procedural time was significantly correlated to the needle deviation. The mean deviations in the raised-RFP-IDDS cohort were consistently lower compared to the recessed-RFP-IDDS cohort (first refill procedure 4.0 vs. 8.5, P < 0.001; second procedure 5.9 vs. 8.1, P = 0.074). CONCLUSION: The results of this study suggest that the manual localization of the RFP for raised-RFP-IDDSs is moderately accurate, and more accurate if compared to previously published accuracy of the template-guided technique for recessed-RFP-IDDSs.