Successful outcome following a multimodal pelvic rehabilitation program in a woman with neurogenic bladder and bowel dysfunction: A case report

BACKGROUND

Neurogenic bladder and bowel dysfunctions lead to physical, social, and emotional disability and affects one's quality of life. Initial treatment is conservative including several rehabilitation techniques such as pelvic floor muscle training, biofeedback, electrical stimulation, and posterior tibial nerve stimulation.

OBJECTIVE

In this case report, a 45-year-old woman with neurogenic bladder and bowel dysfunction was presented.

CASE DESCRIPTION

Her urinary and fecal incontinence symptoms began twenty years before this episode of care, after an incomplete spinal cord injury secondary to spinal ependymoma and syringomyelia. She discontinued medical treatments due to side effects and ceased intermittent catheterization. A multimodal pelvic rehabilitation program was administered consisting of posterior tibial nerve stimulation, active pelvic floor muscle training accompanied by biofeedback, and electrical stimulation of pelvic floor muscles.

OUTCOMES

There were clinically important favorable differences in the scores of King's health questionnaire (reductions in symptom severity from 25 to 18 and in each of the impact of incontinence, physical and social limitations, personal relationships, sleep/energy, and severity measures from 100 to 67), pelvic floor distress inventory (decreased from 257 to 146) and female sexual function index (increased from 15.1 to 25.1) after 12 weeks of a multimodal pelvic rehabilitation program. Manual muscle tests demonstrated improvements in pelvic floor muscle strength and endurance.

CONCLUSION

A 12-week multimodal pelvic rehabilitation program reduced urinary and fecal incontinence symptoms, together with improvements in her sexual life and alleviation of neuropathic pain.

Ladder-based resistance training with the progression of training load altered the tibial nerve ultrastructure and muscle fiber area without altering the morphology of the postsynaptic compartment

Scientific evidence regarding the effect of different ladder-based resistance training (LRT) protocols on the morphology of the neuromuscular system is scarce. Therefore, the present study aimed to compare the morphological response induced by different LRT protocols in the ultrastructure of the tibial nerve and morphology of the motor endplate and muscle fibers of the soleus and plantaris muscles of young adult Wistar rats. Rats were divided into groups: sedentary control (control, n = 9), a predetermined number of climbs and progressive submaximal intensity (fixed, n = 9), high-intensity and high-volume pyramidal system with a predetermined number of climbs (Pyramid, n = 9) and lrt with a high-intensity pyramidal system to exhaustion (failure, n = 9). myelinated fibers and myelin sheath thickness were statistically larger in pyramid, fixed, and failure. myelinated axons were statistically larger in pyramid than in control. schwann cell nuclei were statistically larger in pyramid, fixed, and failure. microtubules and neurofilaments were greater in pyramid than in control. morphological analysis of the postsynaptic component of the plantar and soleus muscles did not indicate any significant difference. for plantaris, the type i myofibers were statistically larger in the pyramid and fixed compared to control. the pyramid, fixed, and failure groups for type ii myofibers had larger csa than control. for soleus, the type i myofibers were statistically larger in the pyramid than in control. pyramid and fixed had larger csa for type ii myofibers than control and failure. the pyramid and fixed groups showed greater mass progression delta than the failure. We concluded that the LRT protocols with greater volume and progression of accumulated mass elicit more significant changes in the ultrastructure of the tibial nerve and muscle hypertrophy without endplate changes.

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.

Short-term Dorsal Genital Nerve Stimulation Increases Subjective Arousal in Women With and Without Spinal Cord Injury: A Preliminary Investigation

OBJECTIVES

Female sexual dysfunction (FSD) affects an estimated 40% of women. Unfortunately, FSD is understudied, leading to limited treatment options for FSD. Neuromodulation has shown some success in alleviating FSD symptoms. We developed a pilot study to investigate the short-term effect of electrical stimulation of the dorsal genital nerve and tibial nerve on sexual arousal in healthy women, women with FSD, and women with spinal cord injury (SCI) and FSD.

MATERIALS AND METHODS

This study comprises a randomized crossover design in three groups: women with SCI, women with non-neurogenic FSD, and women without FSD or SCI. The primary outcome measure was change in vaginal pulse amplitude (VPA) from baseline. Secondary outcome measures were changes in subjective arousal, heart rate, and mean arterial pressure from baseline. Participants attended one or two study sessions where they received either transcutaneous dorsal genital nerve stimulation (DGNS) or tibial nerve stimulation (TNS). At each session, a vaginal photoplethysmography sensor was used to measure VPA. Participants also rated their level of subjective arousal and were asked to report any pelvic sensations.

RESULTS

We found that subjective arousal increased significantly from before to after stimulation in DGNS study sessions across all women. TNS had no effect on subjective arousal. There were significant differences in VPA between baseline and stimulation, baseline and recovery, and stimulation and recovery periods among participants, but there were no trends across groups or stimulation type. Two participants with complete SCIs experienced genital sensations.

CONCLUSIONS

To our knowledge, this is the first study to measure sexual arousal in response to short-term neuromodulation in women. This study indicates that short-term DGNS but not TNS can increase subjective arousal, but the effect of stimulation on genital arousal is inconclusive. This study provides further support for DGNS as a treatment for FSD.

Immediate and Long-Term Effects of Tibial Nerve Stimulation on the Sexual Behavior of Female Rats

OBJECTIVES

There are limited treatment options for female sexual dysfunction (FSD). Percutaneous tibial nerve stimulation (PTNS) has shown improvements in FSD symptoms in neuromodulation clinical studies, but the direct effects on sexual function are not understood. This study evaluated the immediate and long-term effects of PTNS on sexual motivation and receptivity in a rat model of menopausal women. Our primary hypothesis was that long-term PTNS would yield greater changes in sexual behavior than short-term stimulation.

MATERIALS AND METHODS

In two experiments, after receiving treatment, we placed ovariectomized female rats in an operant chamber in which the female controls access to a male by nose poking. We used five treatment conditions, which were with or without PTNS and no, partial, or full hormone priming. In experiment 1, we rotated rats through each condition twice with behavioral testing immediately following treatment for ten weeks. In experiment 2, we committed rats to one condition for six weeks and tracked sexual behavior over time. We quantified sexual motivation and sexual receptivity with standard measures.

RESULTS

No primary comparisons were significant in this study. In experiment 1, we observed increased sexual motivation but not receptivity immediately following PTNS with partial hormone priming, as compared with priming without PTNS (linear mixed effect models; initial latency [p = 0.34], inter-interval latency [p = 0.77], nose poke frequency [p = 0.084]; eight rats). In experiment 2, we observed trends of increased sexual receptivity (linear correlation for weekly group means; mounts [p = 0.094 for trendline], intromissions [p = 0.073], lordosis quotient [p = 0.58], percent time spent with a male [p = 0.39], decreased percent time alone [p = 0.024]; four rats per condition), and some sexual motivation metrics (linear correlation for weekly group means; nose pokes per interval [p = 0.050], nose poke frequency [p = 0.039], decreased initial latency [p = 0.11]; four rats per condition) when PTNS was applied long-term with partial hormone priming, as compared with hormone-primed rats without stimulation.

CONCLUSIONS

PTNS combined with hormone priming shows potential for increasing sexual motivation in the short-term and sexual receptivity in the long-term in rats. Further studies are needed to examine variability in rat behavior and to investigate PTNS as a treatment for FSD in menopausal women.

Landmarks for a Minimally Invasive Approach for Haglund's Deformity: A Cadaveric Study

INTRODUCTION

Haglund's deformity is a posterosuperior calcaneal prominence often associated with a painful bursa and insertional Achilles tendinopathy. Endoscopic debridement has been previously described; however, the aim of this cadaveric study is to describe landmarks of a minimally invasive surgical (MIS) approach to Haglund's deformity.

METHODS

Twelve specimens were dissected to identify medial and lateral portals for minimally invasive burr placement and anchor placement. A standard ruler was used to measure the distance in millimeters from the medial and lateral neurovascular structures in relation to medial and lateral portals. A separate 7-cm longitudinal incision posterior to the lateral malleolus and a separate 7-cm longitudinal incision posterior to the medial malleolus were made to identify at-risk neurovascular structures.

RESULTS

The average distance from the sural nerve to the lateral portal was 25.7 mm (23-26). The mean distance from the lateral calcaneal branch of the sural nerve to lateral portal was 11.4 mm (10-12). The mean distance from the tibial nerve to the medial portal was 35.3 mm (35-36). Both the medial and lateral incisions were 9.3 mm from the calcaneal tuberosity.

CONCLUSION

The results indicate that the MIS approach to Haglund's deformity resection can be performed reliably without neurovascular compromise.

LEVELS OF EVIDENCE

Level IV.

Unilateral Calf Atrophy: A Case Series of Clinical and Electrodiagnostic Findings With a Review of the Literature

Unilateral calf atrophy may result from several medical conditions, such as lumbar radiculopathy, asymmetric myopathy/dystrophy, a Baker's (popliteal) cyst leading to tibial nerve compression, and disuse atrophy. We present a case series of four patients with unilateral calf atrophy, including chronic neurogenic atrophy (benign focal amyotrophy, one patient), tibial nerve compression at the popliteal fossa by a Baker's cyst (one patient), and disuse atrophy (two patients). All four patients underwent electrodiagnostic (EDX) studies, and two of them had denervation changes of the gastrocnemius. One patient underwent an ultrasound (US), which revealed a large cyst in the popliteal fossa causing compression of the tibial nerve. The differential diagnosis of unilateral calf atrophy as well as diagnostic techniques to confirm the underlying pathology are described. EDX and US studies are useful in differentiating between the varied conditions that may cause asymmetric calf muscle wasting.

Acute dorsal genital nerve stimulation increases subjective arousal in women with and without spinal cord injury: a preliminary investigation

Introduction

Female sexual dysfunction (FSD) impacts an estimated 40% of women. Unfortunately, female sexual function is understudied, leading to limited treatment options for FSD. Neuromodulation has demonstrated some success in improving FSD symptoms. We developed a pilot study to investigate the short-term effect of electrical stimulation of the dorsal genital nerve and tibial nerve on sexual arousal in healthy women, women with FSD, and women with spinal cord injury (SCI) and FSD.

Methods

This study consists of a randomized crossover design in three groups: women with SCI, women with non-neurogenic FSD, and women without FSD or SCI. The primary outcome measure was change in vaginal pulse amplitude (VPA) from baseline. Secondary outcome measures were changes in subjective arousal, heart rate, and mean arterial pressure from baseline. Participants attended one or two study sessions where they received either transcutaneous dorsal genital nerve stimulation (DGNS) or tibial nerve stimulation (TNS). At each session, a vaginal photoplethysmography sensor was used to measure VPA. Participants also rated their level of subjective arousal and were asked to report any pelvic sensations.

Results

We found that subjective arousal increased significantly from before to after stimulation in DGNS study sessions across all women. TNS had no effect on subjective arousal. There were significant differences in VPA between baseline and stimulation, baseline and recovery, and stimulation and recovery periods among participants, but there were no trends across groups or stimulation type. Two participants with complete SCIs experienced genital sensations.

Discussion

This is the first study to measure sexual arousal in response to acute neuromodulation in women. This study demonstrates that acute DGNS, but not TNS, can increase subjective arousal, but the effect of stimulation on genital arousal is inconclusive. This study provides further support for DGNS as a treatment for female sexual dysfunction.

Tibial nerve compression due to osteochondroma of the fibular head: A case report

RATIONALE

Osteochondroma is one of the most common primary benign bone tumors. In most cases, this disease is asymptomatic. However, it may become symptomatic owing to nerve and vascular compression when it affects the knee joint. Isolated tibial nerve palsy caused by proximal fibular osteochondroma is rare.

PATIENTS CONCERNS

A 60-year-old male, was treated for degenerative arthritis of the right knee, referred to the right great toe flexion limitation that occurred 3 weeks prior.

DIAGNOSES

Magnetic resonance imaging revealed compression of the tibial nerve and surrounding muscles due to an osseous lesion in the fibular head. A nerve conduction test confirmed tibial neuropathy in the right lower leg.

INTERVENTIONS

Exploratory surgery was performed to decompress the tibial nerve and remove the bony lesion histopathologically diagnosed as an osteochondroma.

OUTCOMES

Fifty-five months postoperatively, toe flexion recovered to normal. No recurrence of osteochondroma was observed.

LESSONS

As in our case, if a bony lesion is diagnosed on radiographs with neurological symptoms, early decompression surgery is necessary. Moreover, since it can be misdiagnosed as a simple bony spur, magnetic resonance imaging and tissue biopsy are also indicated.

Normative Reference Values of the Tibial Nerve in Healthy Individuals Using Ultrasonography: A Systematic Review and Meta-Analysis

BACKGROUND

High-resolution ultrasound of the tibial nerve has been used for screening of several neurologic disorders, but normative reference values of tibial nerve cross-sectional areas (CSA) have not been well established. Thus, the present meta-analysis was performed to generate normative estimates of tibial nerve CSA at various sites of the lower limb based on ultrasonography.

METHODS

Google Scholar, Scopus and PubMed were searched for potential studies. Studies were required to report tibial nerve CSA in healthy individuals to be included. A random-effect meta-analysis was performed to calculate tibial nerve CSA values. Subgroup and statistical analyses were performed to study covariates.

RESULTS

Forty-eight eligible articles consisting of 2695 limbs were included. The average tibial nerve CSA was found to be 10.9 mm2 at the ankle (95% CI: 9.9-11.8) and should not exceed 11.8 mm2 in healthy adults. At the popliteal fossa, the overall CSA was 21.7 mm2 (95% CI: 17.5-25.8) in healthy adults. At both sites, the average tibial nerve CSA was significantly larger in adults than in children, and the differences by geographical region were not statistically significant. At the ankle, tibial nerve CSA increased with age and body mass index, while at the popliteal fossa it increased with age and weight.

CONCLUSIONS

our findings indicate that the tibial nerve varied not only along its course but also among sub-variables. Establishing normal references values of tibial nerve CSA is helpful to differentiate healthy from diseased tibial nerves such as in diabetic peripheral neuropathy or tarsal tunnel syndrome.

Tibial intraneural ganglion cysts arising from the tibiofemoral joint: illustrative cases

BACKGROUND

Intraneural cysts involving the tibial nerve in the knee region (popliteal fossa) are rare. According to the articular (synovial) theory, which posits a joint origin for this pathology, these cysts originate from either the superior tibiofibular joint (STFJ) or the tibiofemoral (knee) joint. As tibial intraneural cysts arising from the tibiofemoral joint remain poorly understood, the authors present 2 illustrative cases and a review of the world's literature on all tibial intraneural ganglion cysts in the knee region.

OBSERVATIONS

Fourteen cases of tibial intraneural ganglion cysts arising from the tibiofemoral joint were identified in the literature. Different articular branch patterns were demonstrated, which could be explained by the varied, rich articular branch innervation at the knee. Favorable outcomes were observed in cases in which the articular branch had been disconnected and the cyst drained and were comparable to the outcomes seen in tibial intraneural ganglion cysts with an STFJ origin.

LESSONS

Tibial intraneural cysts in the knee region can be subdivided by their joint of origin: the STFJ or the tibiofemoral joint. Those arising from the tibiofemoral joint originate from different areas of the joint and propagate in predictable patterns, with favorable outcomes following surgical intervention when the joint connection is identified and treated. The origin of tibial intraneural cysts from the tibiofemoral joint are more complex than those originating from the STFJ but seem to have similar propagation patterns and outcomes.

An anatomical study of the tibial nerve branches innervating the posterior tibial artery

The arteries of the lower limbs are innervated by vascular branches (VBs) originating from the lumbar sympathetic trunk and branches of the spinal nerve. Although lumbar sympathectomy is used to treat nonreconstructive critical lower limb ischemia (CLLI), it has limited long-term effects. In addition, the anatomical structure of tibial nerve (TN) VBs remain incompletely understood. This study aimed to clarify their anatomy and better inform the surgical approach for nonreconstructive CLLI. Thirty-six adult cadavers were dissected under surgical microscopy to observe the patterns and origin points of VBs under direct vision. The calves were anatomically divided into five equal segments, and the number of VB origin points found in each was expressed as a proportion of the total found in the whole calf. Immunofluorescence staining was used to identify the sympathetic nerve fibers of the VBs. Our results showed that the TN gave off 3-4 VBs to innervate the posterior tibial artery (PTA), and the distances between VBs origin points and the medial tibial condyle were: 24.7 ± 16.3 mm, 91.7 ± 66.1 mm, 199.6 ± 52.0 mm, 231.7 ± 38.5 mm, respectively. They were mainly located in the first (40.46%) and fourth (31.68%) calf segments, and immunofluorescence staining showed that they contained tyrosine hydroxylase-positive sympathetic nerve fibers. These findings indicate that the TN gives off VBs to innervate the PTA and that these contain sympathetic nerve fibers. Therefore, these VBs may need to be cut to surgically treat nonreconstructable CLLI.

Spared nerve injury causes motor phenotypes unrelated to pain in mice

Most animal models of neuropathic pain use targeted nerve injuries quantified with motor reflexive measures in response to an applied noxious stimulus. These motor reflexive measures can only accurately represent a pain response if motor function in also intact. The commonly used spared nerve injury (SNI) model, however, damages the tibial and common peroneal nerves that should result in motor phenotypes (i.e., an immobile or "flail" foot) not typically captured in sensory assays. To test the extent of these issues, we used DeepLabCut, a deep learning-based markerless pose estimation tool to quantify spontaneous limb position in C57BL/6J mice during tail suspension following either SNI or sham surgery. Using this granular detail, we identified the expected flail foot-like impairment, but we also found SNI mice hold their injured limb closer to the body midline compared to shams. These phenotypes were not present in the Complete Freunds Adjuvant model of inflammatory pain and were not reversed by multiple analgesics with different mechanisms of action, suggesting these SNI-specific phenotypes are not directly related to pain. Together these results suggest SNI causes previously undescribed phenotypes unrelated to altered sensation that are likely underappreciated while interpreting preclinical pain research outcomes.

The normal value and influencing factors of shear wave elastography in healthy tibial nerves: A cross-sectional study

Background and Aims

Shear wave elastography is a potential method for evaluating peripheral neuropathy, but lacking reference values. The aim of this study was to measure tibial nerve stiffness in healthy individuals using shear wave elastography and to investigate the influencing factors of tibial nerve stiffness.

Methods

Shear wave elastography of bilateral tibial nerves was performed in 50 healthy individuals 4 cm proximal to the medial malleolus. Mean shear modulus data of tibial nerves were obtained and recorded. Intra- and interobserver agreement were assessed using intraclass correlation coefficients. Differences among groups (grouped by laterality, sex, age, and body mass index) were analyzed with independent-samples t-tests and paired t-tests. Effect size (Cohen's d) was also calculated.

Results

The intra-and interobserver agreement were moderate (intraclass correlation coefficient, 0.700-0.747) for all participants, and was poor (intraclass correlation coefficient, 0.265-0.088) in very thin people (body mass index <18.5 kg/m²). The shear wave elastography measurements of the tibial nerve did not show a significant difference between legs, sexes, or different age groups. Higher values of tibial nerve stiffness were found in thinner participants.

Conclusions

Shear wave elastography is a method to evaluate the stiffness of peripheral nerves. The measurement results were likely influenced by body mass index of the participants.

Transdermal tibial nerve optogenetic stimulation targeting C-fibers

Purpose: To explore whether stimulation of C-fibers in tibial nerves can induce bladder inhibition by optogenetic transdermal illumination. Methods: Ten rats were injected with AAV2/6-hSyn-ChR2(H134R)-EYFP into the tibial nerves. Transurethral cystometry was performed 4 weeks after the virus injection. Illumination (473-nm blue light at 100 mW) was performed with the fiber positioned above the right hind paw near the ankle. The light transmission efficiency was examined with a laser power meter. The effects on cystometry were compared before and after illumination with the bladder infused with normal saline and acetic acid, respectively. Result: Upon transdermal delivery of 473-nm light at a peak power of 100 mW, the irradiance value of 0.653 mW/mm2 at the target region was detected, which is sufficient to activate opsins. The photothermal effect of 473-nm light is unremarkable. Acute inhibitory responses were not observed during stimulation regarding any of the bladder parameters; whereas, after laser illumination for 30 min, a statistically significant increase in bladder capacity with the bladder infused with normal saline (from 0.53 ± 0.04 mL to 0.72 ± 0.05 mL, p < 0.001) and acetic acid (from 0.25 ± 0.02 mL to 0.37 ± 0.04 mL, p < 0.001) was detected. A similar inhibitory response was observed with pulsed illumination at both 10Hz and 50Hz. However, illumination did not significantly influence base pressure, threshold pressure, or peak pressure. Conclusion: In this preliminary study, it can be inferred that the prolonged bladder inhibition is mediated by the stimulation of C-fibers in the tibial nerves, with no frequency-dependent characteristics. Although the 473-nm blue light has limited penetration efficacy, it is sufficient to modulate bladder functions through transdermal illumination on the superficial peripheral nervous system.

Peripheral Nerve Ultrasound for the Differentiation between ALS, Inflammatory, and Hereditary Polyneuropathies

Background and Objectives: Ultrasound (US) is a non-invasive tool for the in vivo detection of peripheral nerve alterations. Materials and Methods: In this study, we applied nerve US to assist the discrimination between the spectrum of amyotrophic lateral sclerosis (ALS, n = 11), chronic inflammatory demyelinating polyradiculoneuropathy (CIDP, n = 5), and genetically confirmed Charcot-Marie-Tooth disease (CMT, n = 5). All participants and n = 15 controls without neurological diseases underwent high-resolution US of the bilateral tibial nerve. The nerve cross-sectional area (CSA) and nerve microvascular blood flow were compared between the groups and related to cerebrospinal fluid (CSF) measures, clinical symptoms, and nerve conduction studies. The analyses are part of a larger multimodal study on the comparison between US and 7 Tesla (7T) magnetic resonance neurography (MRN). Results: The patients and controls were matched with respect to their demographical data. CMT had the longest disease duration, followed by CIDP and ALS. CSA was related to age, weight, and disease duration. CSA was larger in CMT and CIDP compared to ALS and controls. The blood flow was greatest in CIDP, and higher than in CMT, ALS, and controls. In ALS, greater CSA was correlated with greater CSF total protein and higher albumin quotient. The US measures did not correlate with clinical scores or nerve conduction studies in any of the subgroups. Conclusion: Our results point towards the feasibility of CSA and blood flow to discriminate between ALS, CIDP, and CMT, even in groups of small sample size. In ALS, larger CSA could indicate an inflammatory disease subtype characterized by reduced blood-nerve barrier integrity. Our upcoming analysis will focus on the additive value of 7T MRN in combination with US to disentangle the spectrum between more inflammatory or more degenerative disease variants among the disease groups.

Considerations about the multidimensional evaluation of a stab wound tibial neuropathy: a case report

We present a rare case of a traumatic lesion of the tibial fibers of the sciatic nerve with spared peroneal fibers. A 33-year-old victim of a three month earlier stabbing attack came to our attention with gait impairment and weakened left foot plantar flexion and left foot internal rotation and supination. Based upon clinical signs and neurophysiological investigations we suspected that a traumatic injury of the left tibial nerve had occurred. Ultrasound examination detected a lesion of part of the left sciatic nerve, in a different site than expected. The patient was immediately enlisted for a tailored surgical reconstruction.

A Rare Variation of High Division of the Sciatic Nerve and Associated Neuromuscular Variations in the Gluteal Region

Variations in the anatomical division of the sciatic nerve are not uncommon. In this case report, we are presenting a rare variation of the sciatic nerve in relation to the superior gemellus and the presence of anomalous muscle. To the best of our knowledge, the anomalous communicating branches of the posterior cutaneous femoral nerve with tibial and common peroneal nerve and the presence of an anomalous muscle originating from the greater sciatic notch and inserting at ischial tuberosity have not been reported yet in the literature. This anomalous muscle found can be named as 'Sciaticotuberosus' after its origin and insertion. Such variations hold clinical significance as they may contribute to piriformis syndrome, coccydynia, non-discogenic sciatica, and popliteal fossa block failure leading to local anesthesia toxicity and blood vessel traumatization. The current classifications of division of the sciatic nerve are based on its relation to the piriformis muscle. In our case report, the variation of the sciatic nerve in relation to the superior gemellus suggests the need for the revision of current classification systems. Category-like division of the sciatic nerve in relation to the superior gemellus muscle can be added.

Protocols Targeting Afferent Pathways via Neuromuscular Electrical Stimulation for the Plantar Flexors: A Systematic Review

This systematic review documents the protocol characteristics of studies that used neuromuscular electrical stimulation protocols (NMES) on the plantar flexors [through triceps surae (TS) or tibial nerve (TN) stimulation] to stimulate afferent pathways. The review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement, was registered to PROSPERO (ID: CRD42022345194) and was funded by the Greek General Secretariat for Research and Technology (ERA-NET NEURON JTC 2020). Included were original research articles on healthy adults, with NMES interventions applied on TN or TS or both. Four databases (Cochrane Library, PubMed, Scopus, and Web of Science) were systematically searched, in addition to a manual search using the citations of included studies. Quality assessment was conducted on 32 eligible studies by estimating the risk of bias with the checklist of the Effective Public Health Practice Project Quality Assessment Tool. Eighty-seven protocols were analyzed, with descriptive statistics. Compared to TS, TN stimulation has been reported in a wider range of frequencies (5-100, vs. 20-200 Hz) and normalization methods for the contraction intensity. The pulse duration ranged from 0.2 to 1 ms for both TS and TN protocols. It is concluded that with increasing popularity of NMES protocols in intervention and rehabilitation, future studies may use a wider range of stimulation attributes, to stimulate motor neurons via afferent pathways, but, on the other hand, additional studies may explore new protocols, targeting for more optimal effectiveness. Furthermore, future studies should consider methodological issues, such as stimulation efficacy (e.g., positioning over the motor point) and reporting of level of discomfort during the application of NMES protocols to reduce the inherent variability of the results.

Electrical stimulation or tacrolimus (FK506) alone enhances nerve regeneration and recovery after nerve surgery, while dual use reduces variance and combines strengths of each in promoting enhanced outcomes

INTRODUCTION/AIMS

Repaired nerve injuries can fail to achieve functional recovery. Therapeutic options beyond surgery, such as systemic tacrolimus (FK506) and electrical stimulation (E-stim), can improve recovery. We tested whether dual administration of FK506 and E-stim enhances regeneration and recovery more than either therapeutic alone.

METHODS

Rats were randomized to four groups: E-stim, FK506, FK506 + E-stim, and repair alone. All groups underwent tibial nerve transection and repair. Two sets of animals were created to measure outcomes of early nerve regeneration using nerve histology (n = 36) and functional recovery (n = 42) (21- and 42-day endpoints, respectively). Functional recovery was measured by behavioral analyses (walking track and grid walk) and, at the endpoint, muscle mass and force.

RESULTS

Dual E-stim and FK506 administration produced histomorphometric measurements of nerve regeneration no different than either therapeutic alone. All treatments were superior to repair alone (FK506, P < .0001; E-stim, P < .05; FK506 + E-stim, P < .05). The E-stim and FK506 + E-stim groups had improved behavioral recovery compared with repair alone (at 6 weeks: E-stim, P < .05; FK506 + E-stim, P < .01). The FK506 group had improved recovery based on walking-track analysis (at 6 weeks: P < .001) and muscle force and mass (P < .05). The concurrent use of both therapies ensured earlier functional recovery and decreased variability in functional outcomes compared with either therapy alone, suggesting a moderate benefit.

DISCUSSION

Dual administration of FK506 and E-stim showed minimal additive effects to further improve regeneration or recovery compared with either therapy alone. The data suggest the combination of FK506 and E-stim appears to combine the relative strengths of each therapeutic.

The role of ultrasound-guided perineural injection of the tibial nerve with a sub-anesthetic dosage of lidocaine for the diagnosis of tarsal tunnel syndrome

Background

Tarsal tunnel syndrome (TTS) involves entrapment of the tibial nerve at the medial ankle beneath the flexor retinaculum and its branches, the medial and lateral plantar nerves, as they course through the porta pedis formed by the deep fascia of the abductor hallucis muscle. TTS is likely underdiagnosed, because diagnosis is based on clinical evaluation and history of present illness. The ultrasound-guided lidocaine infiltration test (USLIT) is a simple approach that may aid in the diagnosis of TTS and predict the response to neurolysis of the tibial nerve and its branches. Traditional electrophysiological testing cannot confirm the diagnosis and only adds to other findings.

Methods

We performed a prospective study of 61 patients (23 men and 38 women) with a mean age of 51 (29-78) years who were diagnosed with idiopathic TTS using the ultrasound guided near-nerve needle sensory technique (USG-NNNS). Patients subsequently underwent USLIT of the tibial nerve to assess the effect on pain reduction and neurophysiological changes.

Results

USLIT led to an improvement in symptoms and nerve conduction velocity. The objective improvement in nerve conduction velocity can be used to document the pre-operative functional capacity of the nerve. USLIT may also be used as a possible quantitative indicator of whether the nerve has the potential to improve in neurophysiological terms and ultimately inform prognosis after surgical decompression.

Conclusion

USLIT is a simple technique with potential predictive value that can help the clinician to confirm the diagnosis of TTS before surgical decompression.

Evaluation of Gastrocnemius Motor Evoked Potentials Induced by Trans-Spinal Magnetic Stimulation Following Tibial Nerve Crush in Rats

Peripheral nerve injuries induce long-lasting physiological and severe functional impairment due to motor, sensory, and autonomic denervation. Preclinical models allow us to study the process of nerve damage, evaluate the capacity of the peripheral nervous system for spontaneous recovery, and test diagnostic tools to assess the damage and subsequent recovery. Methods: In this study on Sprague-Dawley rats, we: (1) compared the use of two different anesthetics (isoflurane and urethane) for the evaluation of motor evoked potentials (MEPs) induced by trans-spinal magnetic stimulation (TSMS) in gastrocnemius and brachioradialis muscles; (2) monitored the evolution of gastrocnemius MEPs by applying paired-pulse stimulation to evaluate the neuromuscular junction activity; and (3) evaluated the MEP amplitude before and after left tibialis nerve crush (up to 7 days post-injury under isoflurane anesthesia). The results showed that muscle MEPs had higher amplitudes under isoflurane anesthesia, as compared with urethane anesthesia in the rats, demonstrating higher motoneuronal excitability under isoflurane anesthesia evaluated by TSMS. Following tibial nerve crush, a significant reduction in gastrocnemius MEP amplitude was observed on the injured side, mainly due to axonal damage from the initial crush. No spontaneous recovery of MEP amplitude in gastrocnemius muscles was observed up to 7 days post-crush; even a nerve section did not induce any variation in residual MEP amplitude, suggesting that the initial crush effectively severed the axonal fibers. These observations were confirmed histologically by a drastic reduction in the remaining myelinated fibers in the crushed tibial nerve. These data demonstrate that TSMS can be reliably used to noninvasively evaluate peripheral nerve function in rats. This method could therefore readily be applied to evaluate nerve conductance in the clinical environment.

Cross-Sectional Area of the Tibial Nerve in Diabetic Peripheral Neuropathy Patients: A Systematic Review and Meta-Analysis of Ultrasonography Studies

Background: There is a link between diabetic peripheral neuropathy (DPN) progression and the increase in the cross-sectional area (CSA) of the tibial nerve at the ankle. Nevertheless, no prior meta-analysis has been conducted to evaluate its usefulness for the diagnosis of DPN. Methods: We searched Google Scholar, Scopus, and PubMed for potential studies. Studies had to report tibial nerve CSA at the ankle and diabetes status (DM, DPN, or healthy) to be included. A random-effect meta-analysis was applied to calculate pooled tibial nerve CSA and mean differences across the groups. Subgroup and correlational analyses were conducted to study the potential covariates. Results: The analysis of 3295 subjects revealed that tibial nerve CSA was 13.39 mm2 (CI: 10.94−15.85) in DM patients and 15.12 mm2 (CI: 11.76−18.48) in DPN patients. The CSA was 1.93 mm2 (CI: 0.92−2.95, I2 = 98.69%, p < 0.01) larger than DPN-free diabetic patients. The diagnostic criteria of DPN and age were also identified as potential moderators of tibial nerve CSA. Conclusions: Although tibial nerve CSA at the ankle was significantly larger in the DPN patients, its clinical usefulness is limited by the overlap between groups and the inconsistency in the criteria used to diagnose DPN.

Reference Values for the Cross Sectional Area of Normal Tibial Nerve on High-resolution Ultrasonography

AIM

The aim of the study was to establish reference values for the cross-sectional area of the tibial nerve on high-resolution ultrasonography and to investigate the relationship between the cross-sectional area of the tibial nerve and subject's age, gender, height (in cm), weight (in kg) and body mass index.

METHODS

Two hundred subjects of either gender and over 18 years of age with no history of peripheral neuropathy or trauma to the lower limb were evaluated with high-resolution ultrasonography. Mean cross-sectional areas of tibial nerves were measured at two different levels in both lower limbs, first at 1 cm below the bifurcation of the sciatic nerve into tibial and common peroneal nerves (level I) and the second at 1 cm superior and posterior to the medial malleolus (level II).

RESULTS

The mean cross-sectional area measured at level I (0.196 + 0.014 cm²) was larger than the one measured at level II (0.111 ± 0.011 cm²). A positive correlation was found between the mean cross-sectional area and height, weight, and body mass index (p <0.05). Women had smaller cross-sectional areas of the tibial nerves than men at both sites. In addition, no significant relationship was found with the age of the subjects (p >0.05).

CONCLUSION

The established reference values of the cross-sectional area of the tibial nerve will aid in early diagnosis of peripheral neuropathy.

Transcutaneous Tibial Nerve Stimulation as Therapy for Functional Constipation

BACKGROUND

Functional constipation is a common disorder that is difficult to treat on occasion. Symptoms of this condition can per- sist despite dietary modification, exercise, and medication. Results of neuromodulation with nerve stimulation have been promising in terms of efficiency for treatment-resistant patients. This study aimed to investigate the efficacy of bilateral transcutaneous tibial nerve stimulation as a noninvasive treatment method for functional constipation.

METHODS

We evaluated 105 patients with functional constipation diagnosed using the Rome IV criteria. Bilateral transcutaneous elec- trical nerve stimulation was utilized for transcutaneous tibial nerve stimulation for 6 weeks; 3 sessions were conducted every week, with each session lasting for at least 30 minutes. The Constipation Severity Instrument was used before treatment, at the end of 6 weeks, and at 12 weeks (6 weeks after the end of treatment). The effects of transcutaneous tibial nerve stimulation on the time spent in the toilet and the use of softeners were investigated.

RESULTS

Of the 105 patients included in the study, 41 (39%) were male. The mean age was 43.1 (range, 19-64 years). Transcutaneous tibial nerve stimulation was found to reduce the time patients spent in the toilet. The use of softeners decreased from 76.2% to 20% (P < .001). Obstructive defecation (P < .001), colonic inertia (P < .001), pain (P < .001), and Constipation Severity Instrument total score (P < .001) improved after the 6-week treatment period. The treatment effect persisted until the 12th week.

CONCLUSION

Bilateral transcutaneous tibial nerve stimulation is a noninvasive, easily applicable, and effective treatment for functional constipation, without major adverse effects. Large randomized controlled trials are required so that transcutaneous tibial nerve stimula- tion can be established as an alternative treatment for functional constipation that is resistant to standard care and laxative agents.

Tarsal Tunnel Syndrome: Outcome According to Etiology

Surgical results in tarsal tunnel syndrome are variable, and etiology seems to be a factor. Three possible etiologies can be distinguished. The aim of the present study was to compare surgical results according to etiology. Three continuous retrospective series (45 patients overall) of tarsal tunnel syndrome were compared. Group 1 presented a permanent intra- or extra-tunnel space-occupying compressive structure. Group 2 presented intermittent intra-tunnel venous dilatations. Group 3 comprised idiopathic tarsal tunnel syndrome. The mean follow-up was 3.6 +/- 1.8 years. The main endpoint was subjective postoperative improvement on Likert scale. Group 1 reported greater improvement than groups 2 and 3. Preoperative neuropathy on ultrasound was associated with poorer improvement, which was not the case for neuropathy on electromyography. Surgical treatment of tarsal tunnel syndrome provides better results in etiologies involving structural compression.

Tarsal Tunnel Syndrome: An Ultrasound Pictorial Review

Tarsal tunnel syndrome may be idiopathic or may be caused by various conditions: bone disease, thickening of the retinaculum, hematoma, or iatrogenic nerve damage; tendinopathy or tenosynovitis; the presence of supernumerary muscles such as an accessory soleus, peroneocalcaneus internus, or accessory flexor digitorum muscle; bone or joint disorders; expansile tumors or cysts; and venous aneurysm or kinking of the tibial artery. The purpose of this article is to describe and illustrate most of the causes of tarsal tunnel syndrome, as diagnosed by ultrasound, which is a practical, inexpensive method.

Variations in the branching pattern of tibial nerve in foot: a review of literature and relevant clinical anatomy

Considerable variations have been reported regarding the branching pattern of tibial nerve (TN) close to its termination in foot. In order to comprehend the clinical anatomy of heel pain awareness of all the possible variations in relation to terminal branching pattern of TN (close to the tarsal tunnel) is essential. The present study was conducted to undertake a comprehensive review of the variations in tibial nerve branches in foot with particular emphasis on the implications for sensory distribution of these branches. Articles were searched in major online indexed databases using relevant key words. The pattern of termination of TN was noted as either trifurcation or bifurcation. Bifurcation pattern was more commonly observed and is associated with the medial calcaneal nerve (MCN) either arising high or low relative to the tarsal tunnel. The most commonly noted type of bifurcation was proximal to malleolar-calcaneal axis but within the tarsal tunnel. Across all five types of bifurcation reported in literature the termination point of TN ranged from 3 cm proximal to 3 cm distal to malleolar-calcaneal axis and therefore the area beyond this region can be considered as safe zone for performing invasive procedures. MCN showed considerable variations in its origin both in trifurcation and bifurcation pattern pertaining to number of branches (one/two/three) at the point of origin. The origin of inferior calcaneal nerve (ICN) was observed to be relatively less variable as it mostly arose as a branch of lateral plantar nerve (LPN) and sometimes as a direct branch from TN before termination. The frequent variation of MCN in the tarsal tunnel should be kept in mind while undertaking decompression measures in medial ankle region.

Effects of Prestretch on Neonatal Peripheral Nerve: An In Vitro Study

Background  Characterizing the biomechanical failure responses of neonatal peripheral nerves is critical in understanding stretch-related peripheral nerve injury mechanisms in neonates. Objective  This in vitro study investigated the effects of prestretch magnitude and duration on the biomechanical failure behavior of neonatal piglet brachial plexus (BP) and tibial nerves. Methods  BP and tibial nerves from 32 neonatal piglets were harvested and prestretched to 0, 10, or 20% strain for 90 or 300 seconds. These prestretched samples were then subjected to tensile loading until failure. Failure stress and strain were calculated from the obtained load-displacement data. Results  Prestretch magnitude significantly affected failure stress but not the failure strain. BP nerves prestretched to 10 or 20% strain, exhibiting significantly lower failure stress than those prestretched to 0% strain for both prestretch durations (90 and 300 seconds). Likewise, tibial nerves prestretched to 10 or 20% strain for 300 seconds, exhibiting significantly lower failure stress than the 0% prestretch group. An effect of prestretch duration on failure stress was also observed in the BP nerves when subjected to 20% prestretch strain such that the failure stress was significantly lower for 300 seconds group than 90 seconds group. No significant differences in the failure strains were observed. When comparing BP and tibial nerve failure responses, significantly higher failure stress was reported in tibial nerve prestretched to 20% strain for 300 seconds than BP nerve. Conclusion  These data suggest that neonatal peripheral nerves exhibit lower injury thresholds with increasing prestretch magnitude and duration while exhibiting regional differences.

Talar Dome Access Through Posteromedial Surgical Intervals for Fracture Care

BACKGROUND

Posterior talar body fractures are rare injuries without a consensus surgical approach. This study evaluates the accessible area of the talar dome through 2 posteromedial approach intervals (posteromedial [PM] and modified posteromedial [mPM]) both with and without distraction.

METHODS

Ten male cadaveric legs (5 matched pairs) were included. A PM approach, between flexor hallucis longus (FHL) and the tibial neurovascular bundle, and an mPM approach, between FHL and Achilles tendon, was performed on each pair. In total, 4 mm of distraction across the tibiotalar joint was applied with the foot held in neutral position. Accessible dome surface area (DSA) was outlined by drilling with a 1.6-mm Kirschner wire with and without distraction. Specimens were explanted and analyzed by micro-computed tomography with 3-dimensional reconstruction. Primary outcomes were total accessible DSA and sagittal plane access at predetermined intervals.

RESULTS

The PM approach allowed access to 19.1% of the talar DSA without distraction and 33.1% of the talar dome with distraction (P < .001). The mPM approach provided access to 20.4% and 35.6% of the talar DSA without and with distraction (P < .001). Both approaches demonstrated similar sagittal plane access at all intervals except the lateral border of the talus, where the mPM approach provided greater access both without distraction (20.5% vs 4.38%, P = .002) and with distraction (34.3% vs 17.8%, P = .02).

CONCLUSION

The mPM approach, using an interval between FHL and Achilles tendon, provides similar access to the posterior surface of talar dome and better sagittal plane access to the most lateral portion of the dome. The mPM interval provides the advantage of avoiding direct dissection of the tibial nerve or posterior tibial artery. Using an external fixator for distraction can improve talar dome visualization substantially.

LEVEL OF EVIDENCE

Level V, Cadaveric Study.

Previously Unreported Sciatic Nerve Variation: Case Report

The sciatic nerve typically follows its course through the greater sciatic foramen, below the piriformis muscle, and down the posterior aspect of the thigh, but many anatomical variations exist. Herein, we report an unusual relationship between the sciatic nerve and piriformis muscle in which the split common fibular nerve went through the piriformis and had a variant communication with the tibial nerve. To our knowledge, this anatomical variation has not been previously reported. Such variants are important to fully understand pathologies involving the sciatic nerve.

Effects of targeted muscle reinnervation on spinal cord motor neurons in rats following tibial nerve transection

Targeted muscle reinnervation (TMR) is a surgical procedure used to transfer residual peripheral nerves from amputated limbs to targeted muscles, which allows the target muscles to become sources of motor control information for function reconstruction. However, the effect of TMR on injured motor neurons is still unclear. In this study, we aimed to explore the effect of hind limb TMR surgery on injured motor neurons in the spinal cord of rats after tibial nerve transection. We found that the reduction in hind limb motor function and atrophy in mice caused by tibial nerve transection improved after TMR. TMR enhanced nerve regeneration by increasing the number of axons and myelin sheath thickness in the tibial nerve, increasing the number of anterior horn motor neurons, and increasing the number of choline acetyltransferase-positive cells and immunofluorescence intensity of synaptophysin in rat spinal cord. Our findings suggest that TMR may enable the reconnection of residual nerve fibers to target muscles, thus restoring hind limb motor function on the injured side.

The anatomical, electrophysiological and histological observations of muscle contraction units in rabbits: a new perspective on nerve injury and regeneration

In the conventional view a muscle is composed of intermediate structures before its further division into microscopic muscle fibers. Our experiments in mice have confirmed this intermediate structure is composed of the lamella cluster formed by motor endplates, the innervating nerve branches and the corresponding muscle fibers, which can be viewed as an independent structural and functional unit. In this study, we verified the presence of these muscle construction units in rabbits. The results showed that the muscular branch of the femoral nerve sent out 4–6 nerve branches into the quadriceps and the tibial nerve sent out 4–7 nerve branches into the gastrocnemius. When each nerve branch of the femoral nerve was stimulated from the most lateral to the medial, the contraction of the lateral muscle, intermediate muscle and medial muscle of the quadriceps could be induced by electrically stimulating at least one nerve branch. When stimulating each nerve branch of the tibial nerve from the lateral to the medial, the muscle contraction of the lateral muscle 1, lateral muscle 2, lateral muscle 3 and medial muscle of the gastrocnemius could be induced by electrically stimulating at least one nerve branch. Electrical stimulation of each nerve branch resulted in different electromyographical waves recorded in different muscle subgroups. Hematoxylin-eosin staining showed most of the nerve branches around the neuromuscular junctions consisted of one individual neural tract, a few consisted of two or more neural tracts. The muscles of the lower limb in the rabbit can be subdivided into different muscle subgroups, each innervated by different nerve branches, thereby allowing much more complex muscle activities than traditionally stated. Together, the nerve branches and the innervated muscle subgroups can be viewed as an independent structural and functional unit. This study was approved by the Animal Ethics Committee of Peking University People’s Hospital (approval No. 2019PHE027) on October 20, 2019.

Supersonic shear wave imaging of the tibial nerve for diagnosis of diabetic peripheral neuropathy: A meta-analysis

BACKGROUND

Diabetic peripheral neuropathy (DPN) is the most common diabetes-associated complication and imposes a significant burden to healthcare systems. Thus, early diagnosis of DPN is extremely critical for management and outcome of diabetic patients. Supersonic Shear Wave Imaging (SSI) enables the noninvasive measurement of nerve stiffness. However, previous studies on SSI in the diagnosis of DPN were limited in sample sizes and reported various results. In this meta-analysis, we aimed to obtain comprehensive evidence on the value of tibial nerve stiffness measurement by SSI in the diagnosis of DPN.

METHODS

A comprehensive literature search in English and Chinese electronic database was conducted for studies (published until January 25, 2022) that investigated the diagnostic performance of tibial nerve stiffness measurement by SSI for detecting DPN. Summary receiver operating characteristics (SROC) modelling was constructed to conduct the meta-analysis of diagnostic accuracy of SSI for detecting DPN.

RESULTS

Finally, a total of 12 eligible studies with 1325 subjects were included for evaluation, and a meta-analysis was conducted to evaluate the diagnostic performance of tibial nerve stiffness measurement by SSI for detecting DPN. For tibial nerve stiffness measurement by SSI, the summary sensitivity and specificity for the diagnosis of DPN were 80% (95% confidence interval [CI]: 73%-86%) and 86% (95% CI: 82%-89%), respectively. The summary area under the ROC curve (AUROC) value of the SROC was 0.90 (95% CI: 0.87-0.92), for diagnosing DPN. A subgroup analysis of 11 SSI studies from China revealed similar diagnostic performance, with a summary sensitivity of 79% (95% CI: 72%-85%), specificity of 86% (95% CI: 82%-89%) and summary AUROC value of the SROC of 0.90 (95% CI: 0.87-0.92) for diagnosing DPN.

CONCLUSIONS

Our meta-analysis suggests that a tibial nerve stiffness measurement by SSI shows good performance in diagnosing DPN and has considerable potential as a noninvasive tool for detecting DPN.

Shear Wave Elastography in the Diagnosis of Peripheral Neuropathy in Patients With Chronic Kidney Disease Stage 5

OBJECTIVE

To observe the feasibility of shear wave elastography (SWE) in the diagnosis of peripheral neuropathy in patients undergoing hemodialysis [chronic kidney disease stage 5 dialysis (CKD5D)].

METHODS

Forty patients with CKD5D were divided into a uremic peripheral neuropathy (UPN) group (n = 25) and a non-UPN group (n = 15) according to the results of a neuro-electrophysiological examination. Sixteen healthy control subjects were also enrolled in this study. Two-dimensional ultrasound examination was conducted, and SWE was then performed to measure Young's modulus of the tibial nerve. The left and right diameters (D1), anterior and posterior diameters (D2), perimeter (C), cross-sectional area (CSA), and Young's modulus (E) were measured three times at the same non-entrapment site. The average values were recorded and calculated. The following evaluation indices were also analyzed: sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the receiver operating characteristic curve (AUC).

RESULTS

D1, D2, C, and CSA were not significantly different among the three groups (P > 0.05). However, the difference in the E value among the three groups was statistically significant (P < 0.05). The AUC was 0.889 based on the E value. Using a tibial nerve E value of 48.35 kPa as the cutoff value, the sensitivity, specificity, PPV, and NPV were 86.0%, 84.0%, 81.1%, and 88.1%, respectively.

CONCLUSIONS

SWE is useful for the diagnosis of peripheral neuropathy in patients with CKD5D. Young's modulus of 48.35 kPa for the tibial nerve is the optimal cutoff value and has the best diagnostic efficiency for peripheral neuropathy in CKD5D patients.

Peripheral schwannomas of the tibial nerve: surgical results in a case series

BACKGROUND AND AIM OF THE WORK

Schwannomas of the lower limb are uncommon benign tumors and those arising from Tibial Nerve are particularly rare. We report our experience on the topic, with particular attention to clinical presentation and lower limbs overall functionality before and after treatment. Our aim is to assess clinical impairment caused by the tumor and evaluate the effectiveness of surgical treatment.

MATERIALS AND METHODS

Time between symptoms outbreak and diagnosis, as well as pre- operative tumor size were evaluated for each case. Pre-operative and post-operative overall lower limb functionality were assessed using both MSTS and LEFS scores. Sensitive symptoms and muscular strength were also evaluated before and after surgery.

RESULTS

7 patients were included in our study. The mean follow-up was 22.9 months. Average diagnostic delay was 8 months and tumor size was 29.3mm. Before surgery each patient had positive Hoffmann-Tinel sign and an at least mild paresthesia, 57% of our cases had slight reduction of muscular strength. Pre-operative MSTS score was 24.4 and LEFS score was 64.7. Tumor size and diagnostic delay were associated with pre-operative functionality. No major local complication was recorded during or after surgery. Each patient with pre-operative sensitive or motorial deficit benefited the effects of surgical treatment.

CONCLUSIONS

Our cases suggest early diagnosis could reduce the impact of the disease on patients' activities of daily living and quality of life. Surgery, for its part, represents a safe and reliable approach to Tibial Nerve schwannomas with good chances of clinical and functional remission.

Neurotoxins subvert the allosteric activation mechanism of SARM1 to induce neuronal loss

SARM1 is an inducible TIR-domain NAD+ hydrolase that mediates pathological axon degeneration. SARM1 is activated by an increased ratio of NMN to NAD+, which competes for binding to an allosteric activating site. When NMN binds, the TIR domain is released from autoinhibition, activating its NAD+ hydrolase activity. The discovery of this allosteric activating site led us to hypothesize that other NAD+-related metabolites might activate SARM1. Here, we show the nicotinamide analog 3-acetylpyridine (3-AP), first identified as a neurotoxin in the 1940s, is converted to 3-APMN, which activates SARM1 and induces SARM1-dependent NAD+ depletion, axon degeneration, and neuronal death. In mice, systemic treatment with 3-AP causes rapid SARM1-dependent death, while local application to the peripheral nerve induces SARM1-dependent axon degeneration. We identify 2-aminopyridine as another SARM1-dependent neurotoxin. These findings identify SARM1 as a candidate mediator of environmental neurotoxicity and suggest that SARM1 agonists could be developed into selective agents for neurolytic therapy.

Retrospective study of the ultrasound characteristics of the tibial nerve in patients with type 2 diabetic peripheral neuropathy

BACKGROUND

Ultrasound is a promising imaging examination for type 2 diabetic peripheral neuropathy (DPN). This study aimed to explore the risk factors of ultrasound diagnostic characteristics in the tibial nerves of patients with type 2 DPN.

METHODS

The Michigan Neuropathy Screening Instrument (MNSI) was used for neuropathy evaluation, and 520 patients with type 2 diabetes were divided into a DPN group and non-DPN (NDPN) group with 2 points as the cut-off value. The two groups were matched at a ratio of 1:1 according to age, BMI, calf circumference, and gender, resulting in 44 matched pairs. The dependent variable was type 2 DPN and the concomitant variables were the width, thickness, cross-sectional area, and unclear honeycomb-like structure of the tibial nerve. A 1:1 matched conditional logistic regression model was established to analyze which ultrasound diagnostic characteristics of the tibial nerve were risk factors for type 2 DPN.

RESULTS

The thickness (OR =5.176, P=0.043) and cross-sectional area (OR =1.659, P=0.030) of the tibial nerve were risk factors for the diagnosis of DPN, while the width and unclear honeycomb-like structure of the nerve were not (P>0.05). In the diagnosis of DPN, the area under the receiver operating characteristic (ROC) curve of the cross-sectional area of the tibial nerve was 0.747, and the sensitivity, specificity, positive predictive value, and negative predictive value were 61.36%, 95.45%, 93.10%, and 71.20%, respectively. The area under the ROC curve of tibial nerve thickness was 0.867, and the sensitivity, specificity, positive predictive value, and negative predictive value were 81.82%, 90.91%, 90.00%, and 83.30%, respectively. The area under the ROC curve of thickness was larger than that of cross-sectional area of the tibial nerve (z statistic =1.800, P=0.07).

CONCLUSIONS

The thickness and cross-sectional area of the tibial nerve measured by ultrasound are risk factors for type 2 DPN. The diagnostic sensitivity of the thickness is higher than the cross-sectional area, while the diagnostic specificity of the cross-sectional area is higher than the thickness.

Exercise induced neuropathic lower leg pain due to a tibial bone exostosis

Objectives: The differential diagnosis of chronic exercise induced lower leg pain in sporters includes compartment syndrome and medial tibial stress syndrome. However, severe discomfort may also be caused by nerve entrapment.Methods: Here we present a marathon runner who reports pain day and night in the lower leg. Deep palpation suggested the presence of a bony tumor deep in the calf musculature, and digital pressure on the soleal sling was painful and elicited paresthesias in the foot. A swab test indicated a hypo-esthetic sole of the foot. Imaging revealed the presence of a tibial exostosis that was hypothesized to narrow the soleal tunnel and irritate the tibial nerve.Results: Via a medial infragenual approach, the soleal tunnel was opened. A bony prominence was found in direct contact to the tibial nerve. Resection of the exostosis with tibial nerve neurolysis completely abolished all of his symptoms.Conclusion: An awkward lower leg discomfort that is present at night and worsens during exercise combined with altered foot sole skin sensation in the presence of a tibial bone exostosis may suggest tibial nerve neuropathy. If conservative therapies fail, resection and neurolysis is advised.

Foot Reanimation Using Double Nerve Transfer to Deep Peroneal Nerve: A Novel Technique for Treatment of Neurologic Foot Drop

BACKGROUND

Our primary objective was to assess the efficacy of a new technique for foot reanimation in patients with neurologic foot drop using double nerve transfer from the tibial to the deep peroneal nerve. Our secondary objective was to document the technical nuances of our technique.

METHODS

Thirty-one patients with common peroneal nerve injury between October 2015 and March 2019 were prospectively enrolled in the study. Patients underwent a transfer of the tibial nerve branches to flexor digitorum longus and lateral head of gastrocnemius to the deep peroneal nerve. Motor recovery, range of ankle dorsiflexion, pain, leg girth, and complications were examined as outcome measures. The modified Medical Research Council (MRC) scale was adopted to assess the motor power recovery. All patients were followed up for a minimum of 1 year.

RESULTS

Motor recovery of M3 or M4 grade of tibialis anterior, extensor hallucis longus, and extensor digitorum longus was achieved in 15 of 31, 13 of 31, and 12 of 31 patients, respectively. Those patients could discontinue use of orthosis. Most patients with high-energy traumas or knee-level injuries failed to recover antigravity function. Only 2 patients reported weak postoperative toe plantarflexion. Our patients achieved significant improvement of the pain perception and range of active ankle motion at the final follow-up.

CONCLUSION

The double nerve transfer technique represented a feasible and safe surgical option. It has been shown to improve function in some patients with neurologic foot drop resulting from a less than 12-month injury of the deep peroneal nerve.

LEVEL OF EVIDENCE

Level IV, therapeutic.

Percutaneous versus Transcutaneous Electrical Stimulation of the Posterior Tibial Nerve in Idiopathic Overactive Bladder Syndrome with Urinary Incontinence in Adults: A Systematic Review

BACKGROUND

Percutaneous electrical stimulation and transcutaneous electrical stimulation (PTNS and TTNS) of the posterior tibial nerve are internationally recognized treatment methods that offer advantages in terms of treating patients with overactive bladder (OAB) who present with urinary incontinence (UI). This article aims to analyze the scientific evidence for the treatment of OAB with UI in adults using PTNS versus TTNS procedures in the posterior tibial nerve.

METHODS

A systematic review was conducted, between February and May 2021 in the Web of Science and Scopus databases, in accordance with the PRISMA recommendations.

RESULTS

The research identified 259 studies, 130 of which were selected and analyzed, with only 19 used according to the inclusion requirements established. The greatest effectiveness, in reducing UI and in other parameters of daily voiding and quality of life, was obtained by combining both techniques with other treatments, pharmacological treatments, or exercise.

CONCLUSIONS

TTNS has advantages over PTNS as it is more comfortable for the patient even though there is equality of both therapies in the outcome variables. More research studies are necessary in order to obtain clear scientific evidence.

Ultrasound-Guided Near-Nerve Needle Sensory Technique for the Diagnosis of Tarsal Tunnel Syndrome

Background: Tarsal tunnel syndrome (TTS) is one of the most common entrapment syndromes. Although diagnosis is supported by imaging tests, it has so far been based on clinical findings. Neurophysiological tests are not effective for providing an accurate diagnosis. The objective of this study was to analyze the efficacy of the ultrasound-guided near-nerve needle sensory technique (USG-NNNS) for the diagnosis of TTS Methods: The study population comprised 40 patients referred for a neurophysiological study owing to clinical suspicion of TTS. Routine neurophysiological tests were performed and compared with the results of USG-NNNS. Results: The diagnosis of TTS was achieved in 90% of cases. We found significant differences between lateral plantar sensory recordings with surface electrodes and USG-NNNS techniques for amplitude, nerve conduction velocity (NCV), and duration. As for the medial plantar sensory recordings, differences were found only for duration. No responses were obtained with surface electrode studies in 64.8% of cases. In addition, we observed normal sensory NCV with surface electrodes in 20 patients, although this decreased when the NNNS technique was used. Conclusions: This is the first report of the efficacy of the USG-NNNS technique for confirming the diagnosis of TTS.

Dimensional Changes of the Tarsal Tunnel During Foot and Ankle Positions: Anatomical Study

The tarsal tunnel is a fibrous osseous conduit for the tibial nerve and associated tendons. It is mechanically dynamic, and foot and ankle movements appear to move and change tunnel shape. However, the effect of foot and ankle movements is not clear. The aim of this study was to measure tarsal tunnel dimensions in anatomical position of the foot and ankle and quantify its changes at different positions in cadavers. A cross-sectional study with a total of 16 cryopreserved lower extremities from cadaveric specimens were used. The foot was cut using an anatomical saw at the level of the tarsal tunnel. Measurements of the cross-sectional area (CSA), transverse diameter (TD), longitudinal diameter (LD) were taken in anatomical position and during foot and ankle movements. All the tarsal tunnel measurements were significantly modified by ankle plantar flexion (p < .05). The CSA increased by 68.97 mm² (p < .001), the TD increased by 1.40 mm (p < .002) and the LD increased by 2.55 mm (p < .007). The TD was also significantly modified by the inversion position of the ankle, showing an increase of 0.84 mm (p < .004). The rest of the ankle positions did not produce significant changes in tarsal tunnel measurements. Foot and ankle plantar flexion position produce and increase in the CSA and the TD of the tarsal tunnel at its distal end in cadavers. This could suggest a reduction in tarsal tunnel pressure during plantar flexion.

Twelve-month Durability of a Fully-implanted, Nickel-sized and Shaped Tibial Nerve Stimulator for the Treatment of Overactive Bladder Syndrome with Urgency Urinary Incontinence: A Single-Arm, Prospective Study

OBJECTIVES

To evaluate the safety and efficacy of the eCoin - a nickel-sized, primary battery-powered, neuromodulation device for the treatment of urgency urinary incontinence which is implanted in the lower leg in a 20-minute procedure under local anesthesia. A feasibility clinical trial was conducted and the results after 1 year of treatment with the eCoin are presented.

METHODS

A total of 46 participants with refractory urgency urinary incontinence were included in this prospective, single-arm, open-label study. This study was conducted at 7 sites in the United States and New Zealand. Participants in this study were implanted with the eCoin in the lower leg over the tibial nerve and activated after 4 weeks. Bladder diary data and validated quality-of-life instruments, collected at 3, 6, and 12 months' post-activation, were compared to baseline values.

RESULTS

Responders were defined as those who had a ≥50% reduction in reported episodes of urgency urinary incontinence. At 12 months', 65% of participants were considered responders with 26% of participants achieving complete continence. The median number of urgency urinary incontinence episodes per day decreased from 4.2 at baseline to 1.7 at 12 months'. Seventy percent of participants reported feeling "better", "much better", or "very much better" on the Likert 7-point maximum scale. One participant experienced a related serious adverse event.

CONCLUSION

The eCoin is a safe and effective treatment for urgency urinary incontinence associated with overactive bladder syndrome, with significant reduction or complete resolution of symptoms and no significant safety concerns.

Cross-sectional area reference values for peripheral nerve ultrasound in adults: A systematic review and meta-analysis-Part II: Lower extremity nerves

BACKGROUND AND PURPOSE

Measurement of the cross-sectional area (CSA) of peripheral nerves using ultrasound is useful in the evaluation of focal lesions such as entrapment syndromes and inflammatory polyneuropathies. We performed a systematic review and meta-analysis of published CSA reference values for lower extremity nerves.

METHODS

We included available-to-date nerve ultrasound studies on healthy adults and provide meta-analysis for CSA of the following nerves: fibular nerve at fibular head, popliteal fossa; tibial nerve at popliteal fossa, malleolus; and sural nerve at the level of the two heads of gastrocnemius muscle. We report regression and correlation analyses for age, gender distribution, height, weight, and geographic continent.

RESULTS

We included 16 studies with 1001 healthy volunteers (mean age = 47.9 years) and 4023 examined nerve sites. Calculated mean pooled CSA of fibular nerve at fibular head was 8.4 mm² (95% confidence interval [CI] = 6.8-9.9 mm² , n = 1166), at popliteal fossa was 7.9 mm² (95% CI = 6.6-9.2 mm² , n = 995), of tibial nerve at popliteal fossa was 25.9 mm² (95% CI = 17.5-34.4 mm² , n = 771), at malleolus was 10.0 mm² (95% CI = 7.7-12.4 mm² , n = 779), and of sural nerve was 2.4 mm² (95% CI = 1.7-3.1 mm² , n = 312). Substantial heterogeneity across studies (I²  > 50%) was found only for tibial nerve at popliteal fossa. Subgroup analysis revealed a lower CSA of tibial nerve at popliteal fossa and sural nerve in studies conducted in Europe than in North America and New Zealand.

CONCLUSIONS

We provide the first meta-analysis on CSA reference values for the lower extremities with no or low heterogeneity of reported CSA values in all nerve sites except tibial nerve at popliteal fossa. Our data facilitate the goal of an international standardized evaluation protocol.

Pivotal Study of Leadless Tibial Nerve Stimulation with eCoin® for Urgency Urinary Incontinence: An Open-Label, Single Arm Trial

PURPOSE

A novel leadless tibial nerve stimulator provides a primary battery-powered, coin-sized, minimally invasive option to deliver automatic low-duty cycle stimulation for overactive bladder syndrome therapy. A pivotal trial was conducted to evaluate the safety and efficacy of this investigational device, eCoin®, for treating refractory urgency urinary incontinence.

MATERIALS AND METHODS

This was a prospective, open-label, single arm trial carried out at 15 U.S. medical centers involving 137 subjects with refractory urgency urinary incontinence. After implantation in the lower leg above the fascia over the tibial nerve, eCoin delivered automated stimulation sessions for the duration of the study. The primary efficacy measure was the proportion of subjects who achieved a 50% or greater reduction from baseline in urgency urinary incontinence episodes after 48 weeks of therapy. The primary safety measure was device-related adverse events at the same time point.

RESULTS

Of 137 subjects enrolled, 133 were implanted with eCoin, and 132 were included in the intention-to-treat population. Of those 132 subjects, 98% were female, mean±SD age was 63.9±10.9 years, and baseline daily urgency urinary incontinence episodes were 4.3±3.1. The primary efficacy analysis showed 68% (95% CI: 60%-76%) of subjects experienced at least a 50% reduction in urgency urinary incontinence episodes at 48 weeks post-activation; 16% of implanted subjects experienced device-related events through 52 weeks post-implantation.

CONCLUSIONS

eCoin demonstrated clinical benefit for treating overactive bladder syndrome with automatic delivery of an intermittent low-duty cycle and implanted with a minimally invasive, brief procedure.

Variable Branching Pattern of Tibial Nerve in the Tarsal Tunnel: A Gross Anatomical Study With Clinical Implications

Introduction

Tibial nerve is a larger component of the sciatic nerve. It arises from ventral branches (Anterior Division) - L4, L5, S1-S3. Then it travels along the distal border of the popliteus muscle, deep to gastrocnemius and soleus. In the leg, it is accompanied by the posterior tibial vessels and lies in the tarsal tunnel. It divides into the medial calcaneal nerve at the ankle, medial, and lateral plantar nerves under the flexor retinaculum. It carries sensory information. It can adapt to repeated forces and undergo stretch especially in ankle joint dorsiflexion and inversion of the foot. Compression of the tibial nerve in the tarsal tunnel can cause tarsal tunnel syndrome. Many surgical procedures need tibial nerve block which demands detailed knowledge of its variation.

Materials and methods

The study was cross-sectional and included lower limbs of five embalmed cadavers and 10 separate cadaveric lower limbs and was performed in the Department of Anatomy of Regional Institute of Medical Sciences, Imphal, India. The reference line (1 cm width) joining two landmarks medial malleolus and medial tubercle of calcaneus called the mideo-malleolar-calcaneal axis was determined and bifurcation of the tibial nerve was classified with respect to the axis.

Results

The tibial nerve in all the cases also crossed the posterior tibial vessels. In 11 cases (55%), the bifurcation of the tibial nerve was proximal to the mideo-malleolar-calcaneal axis with a mean distance of 1.86 cm above the axis, and thus comprising the maximum Type I category. Type II category, having bifurcation at the level of the axis, was found in six (30%) cases. Type III category, having three (15%) cases, was recorded to have bifurcation at a mean distance of 1.16 cm.

Conclusion

Proper anatomical knowledge of tibial nerve branching is required to prevent surgical complications, effective nerve block, procurement of tibial nerve graft.

A Rare Case of Tibial Intraneural Ganglion Cyst Arising From the Tibiofibular Joint

Intraneural ganglion cysts are a rare occurrence. They are most commonly found originating from the common peroneal nerve but are also frequently reported on the radial, ulnar, median, sciatic, tibial, and posterior interosseous nerves. A typical clinical presentation is posterior knee and calf pain resulting from tibial neuropathy with preferential degeneration of the popliteus muscle. Symptoms include pain, paresthesias, and decreased strength that originates in the knee and commonly extends to the plantar surface of the foot. These findings can be mistaken for lumbar neuropathies and compression of the sacral nerve roots. Differential diagnosis includes peripheral nerve sheath tumors, Baker’s cysts, extraneural ganglion cysts, and atypical vascular or lymphatic malformations. In this case report, the patient was a 61-year-old male, previously in good health, who presented with progressive pain in his medial left hamstring as well as weakness in left foot plantar flexion and paresthesias in the plantar aspect of his left foot. He first noticed impairments with his ability to push off with his left foot when running. His electromyogram (EMG) was abnormal and subsequent MRI of the left leg showed a complex intraneural ganglion cyst arising from the tibiofibular joint and ascending into the tibial nerve. He underwent indirect decompression through joint resection. Unfortunately, he did not have clinical improvement on one-year follow-up. Overall, symptomatic treatment of intraneural ganglion cyst includes decompression, surgical excision, or minimally invasive decompression by percutaneous aspiration of the ganglion under ultrasound guidance.

Comparison of transcutaneous electrical tibial nerve stimulation for the treatment of overactive bladder: a multi-arm randomized controlled trial with blinded assessment

OBJECTIVE

To compare the effectiveness of tibial nerve transcutaneous electrical nerve stimulation (TENS) for an overactive bladder, considering the sites of application and frequency of attendance.

METHODS

This multi-arm randomized controlled trial enrolled 137 adult women (61.0±9.0 years) with overactive bladder from a university hospital. They underwent 12 sessions of 30-min TENS application and were assigned to five groups: one leg, once a week (n=26); one leg, twice a week (n=27); two legs, once a week (n=26); two legs, twice a week (n=28); and placebo (n=30). Symptoms of overactive bladder and its impact on quality of life were evaluated before and after 6 or 12 weeks of treatment using the Overactive Bladder Questionnaire-V8 and voiding diary. ClinicalTrials.gov: NCT01912885.

RESULTS

The use of one leg, once a week TENS application reduced the frequency of urgency episodes compared with the placebo (1.0±1.6 vs. 1.4±1.9; p=0.046) and frequency of incontinence episodes compared with the placebo (0.7±1.4 vs.1.4±2.2; p<0.0001). The one-leg, twice a week protocol decreased the urinary frequency compared with the two legs, once a week protocol (8.2±3.5 vs. 9.0±5.1; p=0.026) and placebo (8.2±3.5 vs. 7.9±2.7; p=0.02). Nocturia improved using the two legs, once a week protocol (1.5±1.8) when compared with the one leg, twice a week protocol (1.9±2.0) and placebo (1.7±1.6) (p=0.005 and p=0.027, respectively). Nocturia also improved using the two legs, twice a week protocol when compared with the one leg, twice a week protocol (1.3±1.2 vs.1.9±2.0; p=0.011).

CONCLUSION

One-leg stimulation improved the daily urinary frequency, urgency, and incontinence, and the two-leg stimulation once and twice weekly improved nocturia.

Tibial Nerve Schwannoma: An Unexplained Cause of Lateral Foot Pain - A Rare Case Report and Review

Introduction:

Schwannoma is a benign tumor that arises from the peripheral nerve sheath. It presents as a discrete, often tender, and palpable nodule associated with neurogenic pain or paresthesia when compressed or traumatized. The growth rate is usually slow, and these lesions seldom exceed 2 cm in diameter.

Case Report:

We report the case of a schwannoma arising from the tibial nerve located in the left popliteal fossa. The patient presented with the left foot pain in the lateral plantar region without any motor deficit. The pre-operative diagnosis was made with magnetic resonance imaging (MRI) scan. He was subjected for neurolysis and excision biopsy of the lesion. The surgical specimen consisted of encapsulated white-yellow mass with irregular contours, measuring 2 × 3 cm. The cut section revealed cystic degenerations with areas of hemorrhage and necrosis. The patient reported symptom free in the post-operative period and during follow-up. Marginal excision appears to be recommended therapy for this tumorous lesion, without any evidence of recurrence during follow-up.

Conclusion:

A benign nerve sheath tumor of a peripheral nerve could be a possibility for long-standing neuropathic pain in the foot, ankle, and leg, wherein all other possibilities have been ruled out. The meticulous examination of the entire length of the tibial nerve including sciatic nerve by palpation and percussion was helpful in diagnosis which should be confirmed by MRI scan. The excision biopsy remains the gold standard treatment of choice for schwannoma of the peripheral nerve.