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.

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.

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.

Intradiscal Glucocorticoid Injection in Discogenic Back Pain and Influence on Modic Changes: A Systematic Review and Meta-analysis of RCTs.

BACKGROUND: The benefit of intradiscal glucocorticoid injection (IGI) for discogenic low back pain (LBP) remains controversial. OBJECTIVES: The objective of this study was to systematically assess and meta-analyze the efficacy of IGI compared with these control groups. STUDY DESIGN: Systematic review and meta-analysis. METHODS: A comprehensive literature search was performed screening PubMed and Embase through May 2022. Only randomized controlled trials (RCTs) comparing IGI to control groups in adult patients with discogenic lumbar back pain were included. A random effects model was used to pool mean differences of pain intensity (visual analaog scale [VAS] 0-100), and physical function assessed with the Oswestry Disability Index (ODI). Subgroup analyses were stratified by Modic magnetic resonance imaging findings. RESULTS: Seven studies met inclusion criteria with a total of 626 patients. The short-term (< 3 months) follow-up showed a significant pooled mean difference in both pain intensity (-20.1; 95% CI, -25.5 to -14.7) and physical function (-9.9; 95% CI, -16.1 to -3.6). In the intermediate -term follow-up (3 to < 6 months), only physical function remained significantly better in the glucocorticoid group (-13.1; 95% CI, -22.3 to -3.9). There was no clinically meaningful or significant difference in pain scores and physical function at the long-term (>= 6 months) follow-up. A subgroup analysis did not demonstrate an effect of Modic (type I) changes on the efficacy of IGI. LIMITATIONS: A limited number of studies was available and consequently publication bias could not be evaluated using a funnel plot. Statistical heterogeneity was detected among the included studies. CONCLUSION: We conclude that IGI reduces discogenic LBP intensity and improves physical function effectively at short-term follow-up, and continues to improve physical function at intermediate-term. However, 6 months posttreatment, outcomes are similar in comparison to the control groups. The type of Modic change does not appear to be related with the response to IGI. KEY WORDS: Low back pain, lumbar back pain, intradiscal glucocorticoid injection, modic changes, meta-analysis.

Efficacy of Cervical Facet Joint Radiofrequency Ablation Using a Multitined Cannula, a Technical Note, and Observational Study.

BACKGROUND: Chronic cervical facet joint pain is a leading cause of pain and disability. In patients nonresponsive to conservative treatment, cervical facet radiofrequency ablation (RFA) has shown to be efficacious. However, the conventional RFA technique can be cumbersome. A novel RFA technique with a multitined cannula allows for a lateral approach and represents an attractive alternative option for cervical facet RFA. It offers a potentially shorter, less cumbersome procedure, with consequently less x-ray exposure and patient discomfort than the conventional cervical RFA. OBJECTIVES: To describe the novel RFA technique using the lateral approach with the multitined cannula at the cervical facet joints and to assess its efficacy in chronic cervical facet joint pain. STUDY DESIGN: This is a single-center observational study. SETTING: Interventional Pain Management Center, Switzerland. METHODS: The aim of this study is to describe the RFA technique using the lateral approach with the multitined cannula at the cervical facet joints and to assess its efficacy in chronic cervical facet joint pain. Eligible adult patients with chronic (> 3 months) cervical facet joint pain refractory to conservative treatment and confirmed by dual positive medial branch blocks, received a fluoroscopic-guided cervical facet RFA treatment using the multitined cannula. The primary outcome was pain relief. Secondary outcome measures included the proportion of patients reporting a >= 30% reduction of pain intensity 2 months after RFA, patient global impression of change (PGIC), need for pain medication, sleep quality, and patient satisfaction. RESULTS: We included 26 patients. The patients showed a clinically meaningful and significant pain relief at 2 months after cervical facet RFA (mean Numeric Rating Scale of 7.5 [1.9] at baseline to 4.2 [2.4]) and 58% of the patients reported >= 30% reduction of pain. An improvement on the PGIC was reported by 88.2% of the patients. No severe side effects or complications were observed. LIMITATIONS: Key limitations of our study were the relatively small sample size, the lack of a control group, and a relatively short-term follow-up duration. CONCLUSIONS: Our results suggest that cervical facet joint RFA using the novel technique with the multitined cannula results in significant pain reduction and improvement on the PGIC. While the conventional technique requires multiple ablations at each target level, the RFA with the multitined needle requires only a singular ablation, likely sparing time, radiation dose, discomfort, and costs. Our results merit consideration of replacement of the conventional technique with the novel technique using the multitined cannula. However, larger-scale clinical trials with an adequate long-term follow-up period are needed to prove the efficacy of RFA using the multitined cannula in cervical facet joint pain.

Middle column Stent-screw Assisted Internal Fixation (SAIF): a modified minimally-invasive approach to rescue vertebral middle column re-fractures.

BACKGROUND: There is limited literature regarding the re-fracture of a previously augmented vertebral compression fracture (VCF). These re-fractures may present as an asymptomatic remodeling of the vertebral body around the cement cast while in other cases they involve the middle column, at the transition zone between the cement-augmented and non-augmented vertebral body. In the latter, a posterior wall retropulsion is possible and, if left untreated, might progress to vertebral body splitting, central canal stenosis, and kyphotic deformity. There is no consensus regarding the best treatment for these re-fractures. There are cases in which a repeated augmentation relieves the pain, but this is considered an undertreatment in cases with middle column involvement, posterior wall retropulsion, and kyphosis. METHODS: We report four cases of re-fracture with middle column collapse of a previously augmented VCF, treated with the stent-screw assisted internal fixation (SAIF) technique. A modified more postero-medial deployment of the anterior metallic implants was applied, to target the middle column fracture. This modified SAIF allowed the reduction and stabilization of the middle column collapse as well as the partial correction of the posterior wall retropulsion and kyphosis. RESULTS: Complete relief of back pain with stable clinical and radiographic findings at follow-up was obtained in all cases. CONCLUSIONS: In selected cases, the middle column SAIF technique is safe and effective for the treatment of the re-fracture with middle column collapse of a previously cement-augmented VCF. This technique requires precision in trocar placement and could represent a useful addition to the technical armamentarium for VCF treatment.

The effect of perioperative psychological interventions on persistent pain, disability, and quality of life in patients undergoing spinal fusion: a systematic review.

PURPOSE: Patients undergoing spinal fusion are prone to develop persisting spinal pain that may be related to pre-existent psychological factors. The aim of this review was to summarize the existing evidence about perioperative psychological interventions and to analyze their effect on postoperative pain, disability, and quality of life in adult patients undergoing complex surgery for spinal disorders. Studies investigating any kind of psychological intervention explicitly targeting patients undergoing a surgical fusion on the spine were included. METHODS: We included articles that analyzed the effects of perioperative psychological interventions on either pain, disability, and/or quality of life in adult patients with a primary diagnosis of degenerative or neoplastic spinal disease, undergoing surgical fusion of the spine. We focused on interventions that had a clearly defined psychological component. Two independent reviewers used the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) to perform a systematic review on different databases. Risk of bias was evaluated using the Downs and Black checklist. Given study differences in outcome measures and interventions administered, a meta-analysis was not performed. Instead, a qualitative synthesis of main results of included papers was obtained. RESULTS: Thirteen studies, conducted between 2004 and 2017, were included. The majority were randomized-controlled trials (85%) and most patients underwent lumbar fusion (92%). Cognitive behavioral therapy (CBT) was used in nine studies (69%). CBT in the perioperative period may lead to a postoperative reduction in pain and disability in the short-term follow-up compared to care as usual. There was less evidence for an additional effect of CBT at intermediate and long-term follow-up. CONCLUSION: The existing evidence suggests that a reduction in pain and disability in the short-term, starting from immediately after surgery to 3 months, is likely to be obtained when a CBT approach is used. However, there is inconclusive evidence regarding the long-term effect of a perioperative psychological intervention after spinal fusion surgery. Further research is necessary to better define the frequency, intensity, and timing of such an approach in relation to the surgical intervention, to be able to maximize its effect and be beneficial to patients.

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.

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.

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.

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.

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.

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.

Effectiveness of dorsal root ganglion stimulation and dorsal column spinal cord stimulation in a model of experimental painful diabetic polyneuropathy.

AIMS: Conventional dorsal root ganglion stimulation (DRGS) is known to achieve better pain-paresthesia overlap of difficult-to-reach areas like the feet compared to dorsal column spinal cord stimulation (SCS). As in painful diabetic polyneuropathy (PDPN) pain is mostly present in the feet, we hypothesized that DRGS is more effective in relieving pain in PDPN when compared to SCS. METHODS: Diabetes was induced in female Sprague-Dawley rats with an intraperitoneal injection of 65 mg/kg of streptozotocin (STZ; n = 48). Rats with a significant decrease in mechanical paw withdrawal response to von Frey filaments 4 weeks after injection were implanted with DRGS electrodes (n = 18). Rats were assigned to DRGS (n = 11) or sham-DRGS (n = 7). Mechanical paw withdrawal thresholds (WT, measured in grams) in response to DRGS (50 Hz, 0.18 ± 0.05 mA) were assessed with von Frey testing. The results of the experiments on these animals were compared to the results of a previous study using exactly the same model on PDPN animals selected for SCS (n = 8) (40-50 Hz, 0.19 ± 0.01 mA) and sham-SCS (n = 3). RESULTS: In the SCS group, the log10 (10 000 × 50% WT) increased from 4910 to 5211 at t = 15 minutes (P < 0.05) and 5264 at t = 30 minutes (P = 0.11). In the DRGS group, the log10 (10,000 × 50% WT) increased from 4376 to 4809 at t = 15 minutes (P < 0.01) and 5042 at t = 30 minutes (P < 0.01). Both DRGS and SCS induced a similar and complete reversal of mechanical hypersensitivity. After cessation of stimulation (t = 60), the return of the log10 (10 000 × 50% WT) response was significantly faster with DRGS than that of SCS (P < 0.05). CONCLUSIONS: We conclude that conventional DRGS is as effective as SCS in reduction of PDPN-associated mechanical hypersensitivity in STZ-induced diabetic rats. The wash-in effect of DRGS and SCS was similar, but DRGS showed a faster washout course. Long-term efficacy should be studied in future animal research.