Tibial Nerve Research Articles

One-Year Longitudinal Assessment of Patients With CMT1A Using Quantitative MRI.

Intramuscular fat fraction (FF) assessed using quantitative MRI (qMRI) has emerged as one of the few responsive outcome measures in CMT1A suitable for future clinical trials. This study aimed to identify the relevance of multiple qMRI biomarkers for tracking longitudinal changes in CMT1A and to assess correlations between MRI metrics and clinical parameters. qMRI was performed in CMT1A patients at 2 time points, a year apart, and various metrics were extracted from 3-dimensional volumes of interest at thigh and leg levels. A semiautomated segmentation technique was used, enabling the analysis of central slices and a larger 3D muscle volume. Metrics included proton density (PD), magnetization transfer ratio (MTR), and intramuscular FF. The sciatic and tibial nerves were also assessed. Disease severity was gauged using Charcot Marie Tooth Neurologic Score (CMTNSv2), Charcot Marie Tooth Examination Score, Overall Neuropathy Limitation Scale scores, and Medical Research Council (MRC) muscle strength. Twenty-four patients were included. FF significantly rose in the 3D volume at both thigh (+1.04% ± 2.19%, p = 0.041) and leg (+1.36% ± 1.87%, p = 0.045) levels. The 3D analyses unveiled a length-dependent gradient in FF, ranging from 22.61% ± 10.17% to 26.17% ± 10.79% at the leg level. There was noticeable variance in longitudinal changes between muscles: +3.17% ± 6.86% (p = 0.028) in the tibialis anterior compared with 0.37% ± 4.97% (p = 0.893) in the gastrocnemius medialis. MTR across the entire thigh volume showed a significant decline between the 2 time points -2.75 ± 6.58 (p = 0.049), whereas no significant differences were noted for the 3D muscle volume and PD. No longitudinal changes were observed in any nerve metric. Potent correlations were identified between FF and primary clinical measures: CMTNSv2 (ρ = 0.656; p = 0.001) and MRC in the lower limbs (ρ = -0.877; p < 0.001). Our results further support that qMRI is a promising tool for following up longitudinal changes in CMT1A patients, FF being the paramount MRI metric for both thigh and leg regions. It is crucial to scrutinize the postimaging data extraction methods considering that annual changes are minimal (around +1.5%). Given the varied FF distribution, the existence of a length-dependent gradient, and the differential fatty involution across muscles, 3D volume analysis appeared more suitable than single slice analysis.

Peripherally targeted analgesia via AAV-mediated sensory neuron-specific inhibition of multiple pronociceptive sodium channels.

This study reports that targeting intrinsically disordered regions of NaV1.7 protein facilitates discovery of sodium channel inhibitory peptide aptamers (NaViPA) for adeno-associated virus (AAV)-mediated, sensory neuron-specific analgesia. A multipronged inhibition of INa1.7, INa1.6, INa1.3, and INa1.1. but not INa1.5 and INa1.8 was found for a prototype, named NaViPA1, which was derived from the NaV1.7 intracellular loop 1 and is conserved among the TTXs NaV subtypes. NaViPA1 expression in primary sensory neurons (PSNs) of dorsal root ganglia (DRG) produced significant inhibition of TTXs INa but not TTXr INa. DRG injection of AAV6-encoded NaViPA1 significantly attenuated evoked and spontaneous pain behaviors in both male and female rats with neuropathic pain induced by tibial nerve injury (TNI). Whole-cell current clamp of the PSNs showed that NaViPA1 expression normalized PSN excitability in TNI rats, suggesting that NaViPA1 attenuated pain by reversal of injury-induced neuronal hypersensitivity. Immunohistochemistry revealed efficient NaViPA1 expression restricted in PSNs and their central and peripheral terminals, indicating PSN-restricted AAV biodistribution. Inhibition of sodium channels by NaViPA1 was replicated in the human iPSC-derived sensory neurons. These results summate that NaViPA1 is a promising analgesic lead that, combined with AAV-mediated PSN-specific block of multiple TTXs NaVs, has potential as peripheral nerve-restricted analgesic therapeutics.

Comparison of Muscle Regeneration Effects at Different Melittin Concentrations in Rabbit Atrophied Muscle.

This research aimed to explore the healing impacts of Melittin treatment on gastrocnemius muscle wasting caused by immobilization with a cast in rabbits. Twenty-four rabbits were randomly allocated to four groups. The procedures included different injections: 0.2 mL of normal saline to Group 1 (G1-NS); 4 μg/kg of Melittin to Group 2 (G2-4 μg/kg Melittin); 20 μg/kg of Melittin to Group 3 (G3-20 μg/kg Melittin); and 100 μg/kg of Melittin to Group 4 (G4-100 μg/kg Melittin). Ultrasound was used to guide the injections into the rabbits' atrophied calf muscles following two weeks of immobilization via casting. Clinical measurements, including the length of the calf, the compound muscle action potential (CMAP) of the tibial nerve, and the gastrocnemius muscle thickness, were assessed. Additionally, cross-sectional slices of gastrocnemius muscle fibers were examined, and immunohistochemistry and Western blot analyses were performed following two weeks of therapy. The mean regenerative changes, as indicated by clinical parameters, in Group 4 were significantly more pronounced than in the other groups (p < 0.05). Furthermore, the cross-sectional area of the gastrocnemius muscle fibers and immunohistochemical indicators in Group 4 exceeded those in the remaining groups (p < 0.05). Western blot analysis also showed a more significant presence of anti-inflammatory and angiogenic cytokines in Group 4 compared to the others (p < 0.05). Melittin therapy at a higher dosage can more efficiently activate regeneration in atrophied gastrocnemius muscle compared to lower doses of Melittin or normal saline.

Efficacy of Interventions to Improve Cognitive Function in Adults with Spinal Cord Injury: A Systematic Review.

Cognitive impairment is a common complication following spinal cord injury (SCI) and imposes a significant negative impact on adjustment, functional independence, physical and mental health, and quality of life. It is unclear whether interventions for cognitive impairment following SCI are effective. A systematic review of controlled trials was performed to evaluate the effect of interventions on cognitive functions in adults with SCI using search engines: Embase, The Cochrane Library, MEDLINE, Scopus, CINAHL, and Web of Science up to December 2023. Two reviewers independently screened the articles, and study findings were synthesized and summarized. The risk of bias was evaluated using the Cochrane Risk of Bias 2.0 tool. Eight moderate-quality studies were found that investigated the effects of physical exercise/activity-based therapy plus cognitive training or intermittent hypoxia, diet modification and dietary supplements, tibial nerve or cortical stimulation, and drug therapy on cognitive function in SCI. Physical exercise/activity-based therapy plus cognitive training showed most promise for improving cognitive functions, while drug therapy, diet modification, and dietary supplements showed potential for improving cognitive function. However, about half of the participants experienced heightened instability in blood pressure following the administration of midodrine, and one participant reported gastrointestinal side effects after taking omega-3 fatty acids. There was no evidence of improvement in cognitive function for stimulation techniques. The current review highlights the scarcity of research investigating the effectiveness of interventions that target cognitive function after SCI. Further, the effects of these eight studies are uncertain due to concerns about the quality of designs and small sample sizes utilized in the trials, as well as the employment of insensitive neurocognitive tests when applied to adults with SCI. This review highlights a significant gap in knowledge related to SCI cognitive rehabilitation.

Anticholinergic Burden in Patients Treated for Overactive Bladder: Second-Line Therapy with Tibial Nerve Stimulation as a Solution.

Overactive bladder (OAB) is a highly prevalent condition with significant associated comorbidities. Current management guidelines suggest the utilization of anticholinergic medication as a second line after nonpharmacological treatment. Tibial nerve stimulation (TNS), which has previously been thought to have been expensive and inaccessible, was relegated to a third-line therapy. However, given the recently discovered association between anticholinergic medication use and dementia as well as the recent FDA approval of transcutaneous tibial nerve stimulation (TTNS), there may be a need to revisit management guidelines. In this commentary, we identify the two types of TNS, percutaneous tibial nerve stimulation (PTNS) and TTNS and compare them with anticholinergics. By considering their respective efficacies, side-effects profiles, and associated costs, we make the case in this commentary for an update to guidelines that includes TNS as second-line OAB management ahead of anticholinergic medication.

Tarsal Tunnel Syndrome: A Narrative Review

Tarsal tunnel syndrome is a compressive neuropathy of the posterior tibial nerve beneath the flexor retinaculum on the medial ankle. Several intrinsic or extrinsic factors may contribute to pain over the medial plantar aspect of the foot that is aggravated by activities. In the presence of suggestive clinical features, appropriate use of radiographic and electrodiagnostic tests can be helpful. Surgical management is considered in patients who do not respond to non-operative treatment or those who have a space-occupying lesion within the tarsal tunnel. Along with surgical decompression of the posterior tibial nerve, complete removal of the causative space-occupying lesion is needed to prevent recurrence.

Exploring Electrical Neuromodulation as an Alternative Therapeutic Approach in Inflammatory Bowel Diseases

Background and Objectives: This review systematically evaluates the potential of electrical neuromodulation techniques—vagus nerve stimulation (VNS), sacral nerve stimulation (SNS), and tibial nerve stimulation (TNS)—as alternative treatments for inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn’s Disease (CD). It aims to synthesize current evidence on the efficacy and safety of these modalities, addressing the significant burden of IBD on patient quality of life and the limitations of existing pharmacological therapies. Materials and Methods: We conducted a comprehensive analysis of studies from PubMed, focusing on research published between 1978 and 2024. The review included animal models and clinical trials investigating the mechanisms, effectiveness, and safety of VNS, SNS, and TNS in IBD management. Special attention was given to the modulation of inflammatory responses and its impact on gastrointestinal motility and functional gastrointestinal disorders associated with IBD. Results: Preliminary findings suggest that VNS, SNS, and TNS can significantly reduce inflammatory markers and improve symptoms in IBD patients. These techniques also show potential in treating related gastrointestinal disorders during IBD remission phases. However, the specific mechanisms underlying these benefits remain to be fully elucidated, and there is considerable variability in treatment parameters. Conclusions: Electrical neuromodulation holds promise as a novel therapeutic avenue for IBD, offering an alternative to patients who do not respond to traditional treatments or experience adverse effects. The review highlights the need for further rigorous studies to optimize stimulation parameters, understand long-term outcomes, and integrate neuromodulation effectively into IBD treatment protocols.

Dietary Intake and Symptom Severity in Women with Fecal Incontinence.

The goal of this study was to determine whether dietary fat/fiber intake was associated with fecal incontinence (FI) severity. Planned supplemental analysis of a randomized clinical trial evaluating the impact of 12-week treatment with percutaneous tibial nerve stimulation versus sham in reducing FI severity in women. All subjects completed a food screener questionnaire at baseline. FI severity was measured using the seven-item validated St. Mark's (Vaizey) FI severity scale. Participants also completed a 7-day bowel diary capturing the number of FI-free days, FI events, and bowel movements per week. Spearman's correlations were calculated between dietary, St. Mark's score, and bowel diary measures. One hundred and eighty-six women were included in this analysis. Mean calories from fats were 32% (interquartile range [IQR] 30-35%). Mean dietary fiber intake was 13.9 ± 4.3g. The percentage of calories from fats was at the higher end of recommended values, whereas fiber intake was lower than recommended for adult women (recommended values: calories from fat 20-35% and 22-28g of fiber/day). There was no correlation between St. Mark's score and fat intake (r = 0.11, p = 0.14) or dietary fiber intake (r = -0.01, p = 0.90). There was a weak negative correlation between the number of FI-free days and total fat intake (r = -0.20, p = 0.008). Other correlations between dietary fat/fiber intake and bowel diary measures were negligible or nonsignificant. Overall, in women with moderate to severe FI, there was no association between FI severity and dietary fat/fiber intake. Weak associations between FI frequency and fat intake may suggest a role for dietary assessment in the evaluation of women with FI.

Investigation of Optimal Needle Position for Radiofrequency Ablation-Based Blockade of Interspace between the Popliteal Artery and the Posterior Capsule of the Knee: A Cadaveric Study

Background and Objectives: The interspace between the popliteal artery and the posterior capsule of the knee (iPACK) block has been widely used in perioperative settings to control posterior knee pain and can additionally be used for chronic knee pain. In this cadaveric study, we aimed to investigate the needle tip position and its proximity to the articular branch of the tibial nerve (ABTN) during an iPACK-targeted radiofrequency procedure. Materials and Methods: An ultrasound-guided iPACK block was performed on 20 knees of 10 cadavers. We injected 0.1 mL each of blue and green gelatinous dye near the tibial artery (point A) and posterior knee capsule (point B), respectively, and evaluated the spread of both around the ABTN. For a hypothetical conventional radiofrequency ablation (RFA) lesion (diameter, 2.95 mm) and cooled RFA lesion (diameter, 4.9 mm), we counted the number of specimens in which the ABTNs would be captured. Results: The percentage of specimens in which the ABTN would be captured by a cooled RFA lesion was 64.71% at point A and 43.75% at point B (p = 0.334). Meanwhile, the percentage of specimens in which the ABTN would be captured by a conventional RFA lesion was 58.82% from point A and 25% from point B (p = 0.065). Conclusions: When performing an RFA-based iPACK block, the needle tip may be positioned either lateral to the tibial artery or in the space between the posterior knee capsule and the tibial artery. However, more studies with larger samples are needed to verify these results before the clinical use of this procedure can be recommended.

Prevention of axonal loss after immediate dosage titration of immunoglobulin in multifocal motor neuropathy.

To evaluate whether ongoing axonal loss can be prevented in multifocal motor neuropathy (MMN) treated with immunoglobulin G (IgG), a group of patients with a median disease duration of 15.7 years (range: 8.3-37.8), treated with titrated dosages of immunoglobulins, was studied electrophysiologically at time of diagnosis and at follow-up. At follow-up, the Z-score of the compound motor action potential amplitude of the median, fibular, and tibial nerves and the neurological performances were determined. In seven patients with a treatment-free period of 0.3 years (0.2-0.4), there was no progression of axonal loss (p = 0.2), whereas a trend toward further axonal loss by 1.3 Z-scores (0.9-17.0, p = 0.06) was observed in five patients with a treatment-free period of 4.0 years (0.9-9.0). The axonal loss in the group with a short treatment delay was significantly smaller than in the group with a longer treatment delay (p = 0.02). Also, there was an association between treatment delay and ongoing axonal loss (p = 0.004). The electrophysiological findings at follow-up were associated with the isokinetic strength performance, the neurological impairment score, and the disability, supporting the clinical relevance of the electrophysiological estimate of axonal loss. Swift initiation of an immediately titrated IgG dosage can prevent further axonal loss and disability in continuously treated MMN patients.

Comparison of tibial nerve pulsed radiofrequency and intralesional radiofrequency thermocoagulation in the treatment of painful calcaneal spur and plantar fasciitis: A randomized clinical trial.

Ultrasound-guided tibial nerve pulsed radiofrequency (US-TN PRF) and fluoroscopy-guided intralesional radiofrequency thermocoagulation (FL-RFT) adjacent to the painful calcaneal spur are two interventions for pain management in painful calcaneal spur (PCS) and plantar fasciitis (PF). This study aimed to compare the effectiveness of the two procedures. A prospective, randomized, single-blind study. Single-center pain clinic. Forty-nine patients who met the inclusion criteria were randomized into two groups. 25 patients (group U) received US-TN PRF at 42 °C for 240 s, while 24 patients (group F) received intralesional FL-RFT at 80 °C for 90 s. The most severe Numeric Rating Scale (NRS) score during the first morning steps and the American Orthopedic Foot and Ankle Society (AOFAS) ankle hindfoot scores were used to evaluate the effectiveness of the procedures. The study's primary outcome assessed treatment effectiveness using the NRS, whereas the secondary outcomes included changes in the AOFAS score and the incidence of procedure-related mild adverse events. NRS and AOFAS scores significantly improved in groups U and F at 1 and 3 months compared to baseline (p < 0.05), and there was no significant difference between the groups. At month 1, 50% or greater pain relief was achieved in 72% of patients in group U and 75% in group F. No significant difference was observed in the incidence of mild adverse events between the groups. US-TN PRF and intralesional FL-RFT have shown significant effectiveness in the treatment of PCS and PF. Larger randomized controlled trials are needed.

Peripheral Nerve Stimulation in Postoperative Analgesia: A Narrative Review.

Recent research has shown the effectiveness of peripheral nerve stimulators (PNS) in managing chronic pain conditions. Ongoing studies aim to explore its potential application in treating acute postoperative pain states. The purpose of this systematic review is to assess the role of PNS in providing relief for postoperative pain. Clinical studies investigating the use of peripheral nerve stimulators (PNS) for analgesia following various surgeries, such as total knee arthroplasty, anterior cruciate ligament repair, ankle arthroplasty, rotator cuff repair, hallux valgus correction, and extremity amputation, have shown promising results. Lead placement locations include the brachial plexus, sciatic, femoral, tibial, genicular, perineal, sural, radial, median, and ulnar nerves. These studies consistently report clinically significant reductions in pain scores, and some even indicate a decrease in opioid consumption following PNS for postoperative pain. PNS involves the subcutaneous placement of electrode leads to target peripheral nerve(s) followed by delivery of an electric current via an external pulse generator. While the precise mechanism is not fully understood, the theory posits that PNS modulates electrical stimulation, hindering the signaling of nociceptive pain. PNS presents itself as an alternative to opioid therapy, holding promise to address the opioid epidemic by offering a nonpharmacologic approach for both acute and chronic pain states.

Cut-off value for a normal posterior tibial nerve to diagnose tarsal tunnel syndrome amongst people of different race in Pretoria, South Africa.

Posterior tibial nerve (PTN) cross-sectional area (CSA) reference values for the diagnosis of tarsal tunnel syndrome (TTS) using ultrasound imaging exist in several countries but not in South Africa (SA). Therefore, the objective was to measure the CSA reference values for PTN in SA. Ultrasound CSA measurements of PTN in both ankles on 112 participants were performed, the mean measurement was recorded, and the effect of race, age, gender, and body mass index (BMI) were recorded. In this study, the primary variables age and BMI affect the CSA measurement of the PTN. A positive correlation was found between PTN asymptomatic size and age (r = 0.196, P < 0.05), size and BMI (r = 0.200, P < 0.05). Age (categories) had a mean value of 3.17 for the age group 36-45 years (95% confidence interval (CI) 2.9-3.4). The mean BMI was 30.0 kg/m2 (CI 28.57-31.08). As for the asymptomatic PTN, a mean CSA reference value of 0.10 cm2 was obtained. With increase in age and BMI, a greater PTN measurement will occur. Race appears to be a contributing factor, but further research is needed in this regard. The reference CSA value for normal PTN should be set at 0.10 cm2 for all racial groups for a basic musculoskeletal ultrasound exam protocol in South Africa.

Percutaneous tibial nerve stimulation for the overactive bladder: A single-arm trial.

We hypothesise that PTNS is a safe and effective treatment for OAB. Overactive bladder (OAB) is estimated to affect 11.8% of women worldwide, causing diminished quality of life. Lifestyle modifications, muscarinic receptor antagonist and beta-adrenoreceptor agonist remain the mainstay of treatment but are limited by their efficacy and adverse effects. Access to third-line therapies of intravesical botulinum toxin type A or sacral neuromodulation is limited by their invasive nature. Percutaneous tibial nerve stimulation (PTNS) has emerged as a non-invasive treatment option for OAB. This study was a single-arm trial of women requesting third-line treatment for OAB. The primary treatment outcome was patient-reported visual analogue score (VAS) improvement of at least 50%. Secondary outcome measures were Urinary Distress Inventory Short Form (UDI-6) score and two-day bladder diary. Patients also provided feedback on adverse effects encountered. In the 84 women recruited, initial treatment protocol showed a success rate of 77.2% among those who completed treatment based on VAS, with a statistically significant improvement in mean UDI-6 score of 20.13 (P < 0.01, standard deviation: 12.52). Continued success following tapering protocol of 60.8% and a mean maintenance protocol of 14.2 months was achieved. No adverse effects were reported. The results from this study are in concordance with previously published literature on the effectiveness and safety of PTNS as a treatment modality for OAB. Further randomised controlled trials to evaluate the optimal treatment protocol are warranted to establish a standardised regime.

Morphometric assessment of tibial nerve and its branches around the ankle.

It is essential to understand the considerable variations in bifurcation patterns of the tibial nerve (TN) and its peripheral nerves at the level of the tarsal tunnel to prevent iatrogenic nerve injury during surgical nerve release or nerve block. A total of 16 ankles of 8 human cadavers were dissected to investigate the branching patterns of the TN, using 2 imaginary lines passing through the tip of the medial malleolus (MM) as reference lines. Bifurcation patterns and detailed information on the relative locations of the medial plantar, lateral plantar, medial calcaneal, and inferior calcaneal nerves to the reference lines were recorded. The most common bifurcation pattern was Type 1 in 12 ankles (75%), followed by Type 2 in 2 ankles (13%). One medial calcaneal nerve (MCN) was seen in 11 (69%) specimens and 2 MCN branches were seen in 5 (31%) specimen. 88% of the MCN branches bifurcated from the TN, whereas 6% originated from both TN and lateral plantar nerve (LPN). At the level of the tip of the MM, 2 of 7 parameters showed statistically significant difference between both sexes (P < .05). There was a statistically significant difference between left and right ankles in 2 of 7 measurements (P < .05). Further morphometric analysis of the width, distance, and angle between the TN branches and the tip of MM showed a highly variable nature of the location of the peripheral nerve branches.

Comparison of the efficacy of spinal cord stimulation and dorsal root ganglion stimulation in the treatment of painful diabetic peripheral neuropathy: a prospective, cohort-controlled study.

The aim of this study was to compare the clinical outcomes of spinal cord stimulation (SCS) and dorsal root ganglion stimulation (DRG-S) in the treatment of painful diabetic peripheral neuropathy (PDPN). In this prospective cohort study, 55 patients received dorsal column spinal cord stimulation (SCS group) and 51 patients received dorsal root spinal cord stimulation (DRG-S group). The primary outcome was a Numerical Rating Scale (NRS) remission rate of ≥50%, and secondary outcomes included the effects of SCS and DRG-S on quality of life scores (EQ-5D-3L), nerve conduction velocity, and HbA1c, respectively. The percentage of NRS remission rate ≥ 50% at 6 months was 80.43 vs. 79.55%, OR (95% CI): 1.06 (0.38-2.97) in the SCS and DRG-S groups, respectively, and the percentage of VAS remission rate ≥ 50% at 12 months was 79.07 vs. 80.95%, OR (95% CI): 0.89 (0.31-2.58). Compared with baseline, there were significant improvements in EQ-5D and EQ-VAS at 6 and 12 months (p < 0.05), but there was no difference in improvement between the SCS and DRG-S groups (p > 0.05). Nerve conduction velocities of the common peroneal, peroneal, superficial peroneal, and tibial nerves were significantly improved at 6 and 12 months compared with the preoperative period in both the SCS and PND groups (p < 0.05). However, at 6 and 12 months, there was no difference in HbA1c between the two groups (p > 0.05). Both SCS and DRG-S significantly improved pain, quality of life, and lower extremity nerve conduction velocity in patients with PDPN, and there was no difference between the two treatments at 12 months.

Anatomical Safety Area for Periarticular Analgesic Infiltration through the Posterior Capsule in Total Knee Arthroplasty: Radiological Study in Magnetic Resonance.

Background: One of the main challenges of orthopedic surgery is adequate pain management after total knee arthroplasty. This work aimed to determine the anatomical safety area for infiltration through the posterior capsule of the knee in prosthetic surgery using Magnetic Resonance Imaging (MRI). Methods: A descriptive, observational, cross-sectional study was performed on 126 knee MRIs. The variables studied were age, sex, and distance between different neurovascular structures of the popliteal fossa (tibial nerve, common peroneal nerve, and vascular bundle). Data were analyzed for normality (Kolmogorov-Smirnov) and variance homogeneity (Levène). A value of p < 0.05 and a confidence interval of 9% were considered statistically significant for all comparisons. Student's t-test was used to compare the means between independent samples. Results: We observed statistically significant differences between the sexes regarding EP-EPS (external plateau-external popliteal sciatic nerve (common peroneal)), EP-IPS (external plateau-internal popliteal sciatic nerve (tibial)), and IP-PA (internal plateau-popliteal artery) measurements. The average distance between both nerves, EPS-IPS (external popliteal sciatic nerve and internal popliteal sciatic nerve), was 25.96 mm in females, while the value obtained in males was 29.93 mm, but this difference was not statistically significant. Conclusions: The average distance from the posterior capsule to the EPS and IPS nerves is greater in males than in females, despite no statistical differences. The presence of a lateralized arteriovenous bundle reduces the infiltration area of the external compartment. Regarding the safety area, infiltration of the internal compartment is safe since the volume diffuses into the muscle mass of the internal gastrocnemius upon injection. To infiltrate the external compartment, the needle must move at least 2 cm from the midline toward the external side (to exceed the maximum displacement of the neurovascular bundle established at 1.82 cm), and not advance beyond 0.76 cm (minimum distance at which we located the common peroneal nerve in the external compartment).

Analgesic effect of a cholinergic agonist (carbachol) in a sural nerve ligation-induced hypersensitivity mouse model

ABSTRACT Objectives Neuropathic pain is characterized by long-lasting, intractable pain. Sciatic nerve ligation is often used as an animal model of neuropathic pain, and the spared nerve injury (SNI) model, in which the common peroneal nerve (CPN) and tibial nerve (TN) are ligated, is widely used. In the present study, we evaluated the analgesic effect of a cholinergic agonist, carbachol, on a neuropathic pain model prepared by sural nerve (SN) ligation in mice. Methods The SN was tightly ligated as a branch of the sciatic nerve. Mechanical and thermal allodynia, and hyperalgesia were assessed using von Frey filaments and heat from a hot plate. The analgesic effects of intracerebroventricularly-administered morphine and carbachol were compared. Results SN ligation resulted in a significant decrease in pain threshold for mechanical stimulation 1 day after ligation. In response to thermal stimulation, allodynia was observed at 50°C and hyperalgesia at 53 and 56°C 3 days after ligation. Content of thiobarbituric acid reactive substances (TBARS) in the spinal cord increased significantly at 6 and 12 h after ligation. Acetylcholine content of the spinal cord also increased at 5 and 7 days after ligation. Intracerebroventricular administration of carbachol at 7 days after ligation produced a marked analgesic effect against mechanical and thermal stimuli, which was stronger and longer-lasting than morphine at all experimental time points. Conclusion These findings suggest that cholinergic nerves are involved in allodynia and hyperalgesia of the SN ligation neuropathic pain model.

Short-term clinical and manometric outcomes of percutaneous tibial nerve stimulation for faecal incontinence: a large single-centre series

BackgroundFaecal incontinence (FI) is common, with a significant impact on quality of life. Percutaneous tibial nerve stimulation (PTNS) is a therapy for FI; however, its role has recently been questioned. Here we report the short-term clinical and manometric outcomes in a large tertiary centre.MethodsA retrospective review of a prospective PTNS database was performed, extracting patient-reported FI outcome measures including bowel diary, the St Marks’s Incontinence Score (SMIS) and Manchester Health Questionnaire (MHQ). Successful treatment was > 50% improvement in symptoms, whilst a partial response was 25–50% improvement. High-resolution anorectal manometry (HRAM) results before and after PTNS were recorded.ResultsData were available from 135 patients [119 (88%) females; median age: 60 years (range: 27–82years)]. Overall, patients reported a reduction in urge FI (2.5–1) and passive FI episodes (2–1.5; p < 0.05) alongside a reduction in SMIS (16.5–14) and MHQ (517.5–460.0; p < 0.001). Some 76 (56%) patients reported success, whilst a further 20 (15%) reported a partial response. There were statistically significant reductions in rectal balloon thresholds and an increase in incremental squeeze pressure; however, these changes were independent of treatment success.ConclusionPatients report PTNS improves FI symptoms in the short term. Despite this improvement, changes in HRAM parameters were independent of this success. HRAM may be unable to measure the clinical effect of PTNS, or there remains the possibility of a placebo effect. Further work is required to define the role of PTNS in the treatment of FI.

The morphological variability of the piriformis muscle.

The aim of the study is to create several classifications of the piriformis muscle (PM): proximal and distal attachments, potential fusions, and the relationship with the sciatic nerve. It is the first comprehensive anatomical examination of this subject. One hundred and twenty-four lower limbs from 62 cadavers, fixed in 10% formalin, were examined. The piriformis muscle was present in 120 limbs (96.8% of cases). Four types of proximal attachment were described (I-IV). The most common type was Type I, in which the proximal attachment was at the anterior surface of the sacrum, between S2 and S4 (52 lower limbs; 43.3%). The rarest type was Type IV, in which the proximal attachment was at the gluteal surface of the ilium near the margin of the greater sciatic notch and from the gluteus medius (12 cases; 10%). Three types of distal attachment were distinguished. The most common was Type 1, a single tendon. This type comprised two subtypes: A and B (105 lower limbs; 87.5%). The other two types accounted for 12.5% of the total. Fusions were noted between the piriformis muscle and adjacent muscles in 31.7%. Four patterns were observed in which the sciatic nerve ran against the piriformis muscle. The most common variation in the relationship was the common fibular nerve exiting superior to the piriformis muscle and the tibial nerve passing inferior to it (10 cases; 8.3%). The piriformis muscle is highly morphologically variable in both its proximal and distal attachments and its relationship with the sciatic nerve. There are four types of proximal attachment and three types of distal attachment. The piriformis muscle shows numerous fusions with its adjacent muscles: gluteus medius or minimus or superior gemellus. A new (fourth) type of relationship was demonstrated between the piriformis muscle and sciatic nerve. The piriformis muscle was absent in four cases.