Distal symmetrical polyneuropathy in diabetes mellitus patients: Proposition of a new scoring system based on electroneurography findings

BACKGROUND

Neuropathy affects 25% of people with diabetes mellitus. The evaluation of disease severity is still a challenge for modern medicine. Many screening instruments are based primarily on clinical criteria. There is a lack of a simple, reliable and precise scoring system that could improve the classification of neuropathy and monitor disease progression using not only clinical criteria but also electroneurography. There is a need to find sensitive neurography parameters that reflect peripheral nerve impairments in this group of patients.

OBJECTIVES

This study aimed to create a scoring system for diabetic neuropathy, based on electroneurography criteria, that reflects the natural course of the disease. A new scoring system will improve the treatment of patients with diabetes mellitus.

MATERIAL AND METHODS

A total of 113 patients with distal symmetrical polyneuropathy (DSPN) were involved in the study. Median, ulnar, sural, tibial, and peroneal nerves were examined. Parameters such as amplitude, conduction velocity, distal latency, and F wave latency were analyzed. The results of nerve conduction studies in the investigated group were compared to those of the control group, which consisted of 61 healthy volunteers.

RESULTS

The most sensitive parameter of peripheral nerve impairment severity was a reduction of the sensory action potential amplitude in the peroneal nerve by 72.8% (p < 0.05). The observation of changes in sensory action potential amplitudes in the peroneal nerve is the most important element of our scoring system.

CONCLUSIONS

A new electroneurography scoring system of DSPN severity should be based on sensory and motor action potential amplitudes that reflect axonal loss in the examined nerves and the nature of the disease.

Common Peroneal Nerve Injury Caused by a Wild Boar Attack

Wild boar-inflicted nerve injuries have been very rarely reported in the literature. A 62-year-old man was attacked by a wild boar in eastern Turkey and brought to the emergency department. He had 5 lacerations on the lower extremities and 2 on the posterior thoracic region. In addition to soft tissue lacerations, he sustained a complete laceration of the left common peroneal nerve with a foot drop. The common peroneal nerve was repaired primarily the day after the attack. The patient was discharged after a short hospital stay without any immediate complications; however, at the 10-mo follow-up, he still had a left foot drop.

Characterizing peroneal nerve injury clinicoradiological patterns with MRI in patients with sciatic neuropathy and foot drop after total hip replacement

OBJECTIVE

Sciatic nerve injury following total hip arthroplasty (THA) predominantly affects the peroneal division of the sciatic nerve, often causing a foot drop. This can result from a focal etiology (hardware malposition, prominent screw, or postoperative hematoma) or nonfocal/traction injury. The objective of this study was to compare the clinicoradiological features and define the extent of nerve injury resulting from these two distinct mechanisms.

METHODS

Patients who developed a postoperative foot drop within 1 year after primary or revision THA with a confirmed proximal sciatic neuropathy based on MRI or electrodiagnostic studies were retrospectively reviewed. Patients were divided into two cohorts: group 1 (focal injury), including patients with an identifiable focal structural etiology, and group 2 (nonfocal injury), including patients with a presumed traction injury. Patient demographics, clinical examinations, subsequent surgeries, electrodiagnostic study results, and MRI abnormalities were noted. The Student t-test was used to compare time to onset of foot drop and time to secondary surgery.

RESULTS

Twenty-one patients, treated by one surgeon, met inclusion criteria (8 men and 13 women; 14 primary THAs and 7 revision THAs). Group 1 had a significantly longer time from THA to the onset of foot drop, with a mean of 2 months, compared with an immediate postoperative onset in group 2 (p = 0.02). Group 1 had a consistent pattern of localized focal nerve abnormality on imaging. In contrast, the majority of patients in group 2 (n = 11) had a long, continuous segment of abnormal size and signal intensity of the nerve, while the other 3 patients had a segment of less abnormal nerve in the midthigh on imaging. All patients with a long continuous lesion had Medical Research Council grade 0 dorsiflexion prior to secondary nerve surgeries compared with 1 of 3 patients with a more normal midsegment.

CONCLUSIONS

There are distinct clinicoradiological findings in patients with sciatic injuries resulting from a focal structural etiology versus a traction injury. While there are discrete localized changes in patients with a focal etiology, those with traction injuries demonstrate a diffuse zone of abnormality within the sciatic nerve. A proposed mechanism involves anatomical tether points of the nerve acting as points of origin and propagation for traction injuries, resulting in an immediate postoperative foot drop. In contrast, patients with a focal etiology have localized imaging findings but a highly variable time to the onset of foot drop.

Common Peroneal Nerve Splitting in Proximal Fibular Osteochondroma: A Rare Presentation

Introduction

Osteochondroma is the most common benign tumor of bone. Tumors are metaphyseal in origin and commonly involve distal femur, proximal tibia, and proximal fibula in the lower extremity. Osteochondroma located at proximal fibula can change the normal path of nerves and it may lead to the compression of vessels or peroneal nerve, leading to paralysis.

Case Report

We are reporting a case of an 18-year-old female with proximal fibular osteochondroma causing splitting of common peroneal nerve without any neuropathy.

Conclusion

We strive to make the surgeons aware that, when removing osteochondroma located at proximal fibula, care should be taken to identify the entire nerve at the site of lesion before the removal as a procedure done in a hurry in such a case can cause irreversible damage to the patient.

Acute Foot Drop Caused by Intraneural Ganglion Cyst of the Peroneal Nerve: Literature Review and Case Report

BACKGROUND

Foot drop (FD) is characterized by an inability to lift the foot against gravity because of dorsiflexor muscle weakness. The aim of the present study is to report a clinical case of acute non-traumatic FD in patients with peroneal intraneural ganglion, after performing a scoping review on the methodological management of this disease.

METHODS

We performed a review of the literature and reported the case of a 49-year-old man with acute FD caused by an intraneural ganglion cyst of the peroneal nerve.

RESULTS

Out of a total of 201 articles, 3 were suitable for our review beyond our case report. The acute FD caused by peroneal intraneural ganglion can be managed by a careful clinical-instrumental differential diagnosis. A targeted surgery with subsequent rehabilitation produced a satisfactory motor recovery.

CONCLUSIONS

Acute FD requires an appropriate diagnostic-therapeutic framework to identify and effectively treat the causes in order to promote complete recovery.

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.

Recurrent Peroneal Intraneural Ganglion Cyst: Management and Review of the Literature

Intraneural ganglion cysts have been reported to affect the common peroneal nerve. Peroneal intraneural ganglion cysts are managed through surgical intervention. Despite surgical intervention, intraneural ganglion cysts can recur. Common intraneural ganglion cyst recurrence patterns have been proposed based on the initial surgical management of the cyst. These patterns all emphasize the importance of treatment of the proximal tibiofibular (TF) joint to reduce the risk of cyst recurrence. Although joint resection is the favored intervention in the literature, joint arthrodesis is an option for certain patients. Here, we present a case of a peroneal intraneural ganglion cyst and its recurrence in a 36-year-old male who had previously undergone surgical removal of the cyst three months prior, as well as a review of the current literature that aims to add to our current understanding of intraneural cysts.

Prospective, Randomized, Multicenter Trial of Peroneal Electrical Transcutaneous Neuromodulation vs Solifenacin in Treatment-naïve Patients With Overactive Bladder

PURPOSE

We investigated the safety and efficacy of peroneal electrical transcutaneous neuromodulation using the URIS neuromodulation system in a home-based setting in comparison with standard treatment using solifenacin in treatment-naïve female patients with overactive bladder.

MATERIALS AND METHODS

A total of 120 patients were screened, of whom 77 were randomized in a 2:1 ratio to 12 weeks of treatment with daily peroneal electrical transcutaneous neuromodulation or solifenacin 5 mg. The primary endpoint was safety; efficacy assessments included proportion of responders, defined as subjects with ≥50% reduction in bladder diary-derived variables; Overactive Bladder-Validated 8-question Screener, and European Quality of Life-5 Dimensions questionnaire; and treatment satisfaction after 12 weeks of therapy.

RESULTS

Seventy-one out of 77 randomized patients completed the study. In the peroneal electrical transcutaneous neuromodulation group 6/51 (12%) patients reported a treatment-related adverse event vs 12/25 (48%) in the solifenacin group (P < .001). No clinically significant changes were observed in any other safety endpoint. The proportions of responders in the peroneal electrical transcutaneous neuromodulation group vs the solifenacin group were 87% vs 74% with respect to Patient Perception of Intensity of Urgency Scale grade 3 urgency episodes, 87% vs 75% with respect to grade 3+4 urgency episodes, and 90% vs 94% with respect to urgency incontinence episodes. In post hoc analyses we observed significant improvement over time in multiple efficacy variables in both treatment arms.

CONCLUSIONS

Peroneal electrical transcutaneous neuromodulation is a safe and effective method for overactive bladder treatment associated with a significantly lower incidence of treatment-related adverse events compared to solifenacin and a considerably better benefit-risk profile.

Osteosarcoma of the Proximal Fibula: A Case Report and Review of the Literature

Osteosarcoma is the most common primary malignant bone tumor, especially in younger patients. Diagnosis is based on the combined evaluation of radiological, clinical, and pathological examinations. It is usually located in the distal femur, proximal tibia, and proximal humerus. The fibula is a rare localization for osteosarcoma. Surgery in this region is challenging due to the complex anatomic structures around the knee. Especially the peroneal nerve, lateral collateral ligament (LCL), and popliteal vessel branches are of critical importance. However, additional structures such as the arcuate ligament, biceps femoris, and iliotibial band play an essential role in the stabilization of the knee. Thus, these structures must be protected as much as possible. This case report aims to present the diagnosis and treatment process of conventional osteosarcoma in the proximal fibula, which was located close to the peroneal nerve and required LCL reconstruction after the resection.

Ultrasound-based neuropathy diagnosis in COVID-19 patients in post-intensive care rehabilitation settings. A retrospective observational study

OBJECTIVES

using ultrasound scanning to examine the correlation between increase of Common Fibular Nerve's (CFN) Cross Sectional Area (CSA) and functional impairment of foot dorsiflexor muscles as an early sign of peripheral neuropathy.

DESIGN

retrospective observational study.

SETTING

in-patient rehabilitation unit between November 2020 and July 2021.

PARTICIPANTS

26 inpatients who underwent prolonged hospitilization in ICU'S and were diagnosed with CRYMINE after SARS-COV-2 infection. Physical examination and ultrasound scanning of the CFN and EMG/ENG were carried out on each patient.

INTERVENTIONS

not applicable MAIN OUTCOME MEASURE(S): CFN's CSA at the peroneal head.

RESULTS

we verified a significant increase in the CSA of the CFN measured at the peroneal head in more than 90% of the nerves tested. A cut off value of CFN's CSA of 0,20 cm was used to identify pathological nerves. No correlations with other variables (BMI, ICU days) were found.

CONCLUSION

US scanning of the CFN appears to be an early and specific test in the evaluation of CPN's abnormalities in post COVID-19 patients. US scanning is a reproducible, cost effective, safe and easily administered bedside tool to diagnose a loss of motor function when abnormalities in peripheral nerves are present.

Peroneal intraneural ganglion cyst with a nearly invisible joint connection (even to advocates of the articular theory): illustrative case

BACKGROUND

The articular (synovial) theory describes the formation of intraneural ganglion cysts through defects in the capsule of synovial joints. While the articular theory is gaining significant traction in the literature, it is not universally accepted. Therefore, the authors present a case of a plainly visible peroneal intraneural cyst, although the subtle joint connection was not identified specifically at the time of surgery, with subsequent rapid extraneural cyst recurrence. The joint connection was not immediately evident on review of the magnetic resonance imaging, even to the authors who have a large experience with this clinical entity. The authors report this case to demonstrate that all intraneural ganglion cysts have joint connections, although they may be difficult to identify.

OBSERVATIONS

An occult joint connection in the intraneural ganglion poses a unique diagnostic and management dilemma. High-resolution imaging is a valuable tool used to identify the articular branch joint connection as part of the surgical planning.

LESSONS

Based on the articular theory, all intraneural ganglion cysts will have a joint connection through an articular branch, although this may be small or nearly invisible. Failure to appreciate this connection can lead to cyst recurrence. A high index of suspicion of the articular branch is needed for surgical planning.

Peroneal Nerve Repair with Cross-Bridge Ladder Technique: Parallel End-to-Side Neurorrhaphies

Background  Multiple nerve transfer techniques are used to treat patients with nerve injuries when a primary repair is not possible. These techniques are categorized to end-to-end, end-to-side, and side-to-side neurorrhaphy. Our study aims to explore the utility of the cross-bridge ladder technique (H-shaped), which has shown promising results in animal models and probably underutilized clinically. Methods  Four patients with significant loss of ankle dorsiflexion were seen in the clinic and underwent evaluation, including electrodiagnostic studies. A cross-bridge ladder repair technique was used between the tibial nerve as the donor and the common peroneal nerve as the recipient via one or two nerve grafts coapted in parallel with end-to-side neurorrhaphies. Dorsiflexion strength was measured preoperatively using the Medical Research Council (MRC) grading system and at each postoperative follow-up appointment. Results  All four patients had suffered persistent and severe foot drop (MRC of 0) following trauma that had occurred between 6 and 15 months preoperatively. Three of the four patients improved to an MRC of 2 several months postoperatively. The last patient had an immediate improvement to an MRC of 2 by his first month and had a complete recovery of ankle dorsiflexion within 4 months from surgery. Conclusion  We demonstrate the utility and clinical outcomes of the cross-bridge ladder technique in patients with persistent and prolonged foot drop following trauma. Both early and late recovery were seen while all patients regained motor function, with some patients continuing to improve up to the most recent follow-up. IRB Approval: Obtained 2013-1411-CP005.

Neuropathic pain in peroneal nerve entrapment at the fibular head

BACKGROUND

Peroneal neuropathy at the fibular head (PNFH) is a mononeuropathy that typically presents with drop foot and sensory abnormalities over the skin area innervated by the peroneal nerve.

OBJECTIVE

The aim of the present study was to evaluate neuropathic pain in patients with PNFH.

METHODS

Patients with clinical and electrodiagnostic features consistent with PNFH associated with weight loss, leg postures, or prolonged sleep were included in the present retrospective cohort study. Nerve conduction studies were performed in the bilateral lower extremities of all patients. The Leeds assessment of neuropathic symptoms and signs scale (LANSS) was applied to all patients.

RESULTS

Thirty-two PNFH patients (78% males) were included in the study. The LANSS score in the majority of patients was lower than 12. There was 1 patient with a LANSS score of 12. The electrodiagnostic features of 16 patients were compatible with axonal degeneration. The mean LANSS scores of PNFH patients with and without axonal degeneration were 4.3 ± 3.7 and 5.2 ± 2.9, respectively (p = 0.255).

CONCLUSION

The present study showed that neuropathic pain is a rare symptom in patients with PNFH associated with weight loss, leg postures, or prolonged sleep.

Useful functional recovery and quality of life after surgical treatment of peroneal nerve injuries

Closed injuries to the peroneal nerve recover spontaneously in about a third of patients, but surgery may be needed in the remaining 2/3. The recovery after surgery is not always satisfactory and the patients may need an orthosis or a walking aid to cope with regular daily activities. This study aimed to evaluate the useful functional recovery and quality of life (QoL) in surgically treated patients with peroneal nerve (PN) injuries. The study involved 51 patients who have undergone surgical treatment due to PN injury in our department, within a 15-year period (2006-2020). Thirty patients (59%) were treated with neurolysis, 12 (23%) with nerve repair techniques, and 9 (18%) with tendon transfer (TT). Neurolysis is employed in the least extensive nerve injuries when nerve continuity is preserved and yields a motor recovery ratio of almost 80%. Nerve repairs were followed by 58.33% of patients achieving M3+ recovery, while 41.66% recovered to the useful functional state (M4 or M5) With the use of TTs, all patients recovered to the M3+, while 66.7% recovered to M4. All our results correspond to the results of previous studies. No statistically significant differences were found regarding the QoL of the groups. There is an apparent advantage of neurolysis, over nerve repair, over TT procedure, both in terms of useful functional recovery, and foot-drop-related QoL. However, when involving all aspects of QoL, these advantages diminish. The individual approach leads to optimal results in all groups of patients.

Efficacy of vitamin and antioxidant supplements for treatment of diabetic peripheral neuropathy: systematic review and meta-analysis of randomized controlled trials

ABSTRACTThe results of treatment effect of vitamin or antioxidant intake on diabetic peripheral neuropathy (DPN) was inconsistent. Therefore, we performed a meta-analysis of randomized controlled trials (RCTs) to examine whether these supplements are effective in DPN treatment. We searched seven databases from inception to October 2021. All RCTs of DPN treatments with vitamin and antioxidant supplements were included. We performed sensitivity and subgroup analysis, and also tested for publication bias by the funnel plot and Egger's test. A total of 14 studies with 1384 patients were included in this systematic review. Three high-quality trials showed that vitamin and antioxidant supplements significantly increased sensory nerve conduction velocity (SNCV) of the sural nerve (MD = 2.66, 95%CI (0.60, 4.72), P < 0.05, I²= 0%). Seven studies (758 participants) suggested that these supplements might have improvement on motor nerve conduction velocity (MNCV) of the peroneal nerve in DPN patients with the random-effect model (MD = 0.60, 95%CI (0.28, 0.92), P < 0.05, I²= 65%). In four studies, these supplements could have improved on MNCV of the median nerve with the fixed-effect model (MD = 4.22, 95%CI (2.86, 5.57), P < 0.05, I²= 0%). However, ten studies (841 participants) have suggested that vitamin and antioxidant supplements have not decreased glycosylated haemoglobin (HbA1c). Vitamin and antioxidant supplements may improve the conduction velocity of nerves, including median, sural and peroneal nerves of patients with DPN. But these supplements have not decreased HbA1c in DPN patients. Several trials with a large sample size are needed to provide evidence support for clinical practice in the future.

The Risk of Iatrogenic Peroneal Nerve Injury in Lateral Meniscal Repair and Safe Zone to Minimize the Risk Based on Actual Arthroscopic Position: An MRI Study

BACKGROUND

Lateral meniscal repair using an all-inside meniscal repair device involves a risk of iatrogenic peroneal nerve injury. To our knowledge, there have been no previous studies evaluating the risk of injury with the knee in the standard operational figure-of-4 position with joint dilatation in arthroscopic lateral meniscal repair.

PURPOSE

To evaluate and compare the risk of peroneal nerve injury and establish the safe and danger zones in repairing the lateral meniscus through the anteromedial, anterolateral, or transpatellar portal in relation to the medial and lateral borders of the popliteal tendon (PT).

STUDY DESIGN

Descriptive laboratory study.

METHODS

Using axial magnetic resonance imaging (MRI) studies of knees in the figure-of-4 position with joint fluid dilatation at the level of the lateral meniscus, we drew direct lines to simulate a straight all-inside meniscal repair device deployed from the anteromedial, anterolateral, and transpatellar portals to the medial and lateral borders of the PT. If the line passed through or touched the peroneal nerve, a risk of iatrogenic peroneal nerve injury was noted, and measurements were made to determine the safe and danger zones for peroneal nerve injury in relation to the medial or lateral border of the PT.

RESULTS

Axial MRI images of 29 adult patients were reviewed. Repairing the lateral meniscus through the anteromedial portal in relation to the lateral border of the PT and through the anterolateral portal in relation to the medial border of the PT had a 0% risk of peroneal nerve injury. The "safe zone" in relation to the medial border of the PT through the anterolateral portal was between the medial border of the PT and 9.62 ± 4.60 mm medially from the same border.

CONCLUSION

It is safe to repair the body of the lateral meniscus through the anteromedial portal in the area lateral to the lateral border of the PT or through the anterolateral portal in the area medial to the medial border of the PT.

CLINICAL RELEVANCE

There is a risk of iatrogenic peroneal nerve injury during lateral meniscal repair. Thus, we recommend repairing the lateral meniscal tissue through the anteromedial portal in the area lateral to the lateral border of the PT and using the anterolateral portal in the area medial to the medial border of the PT, as neither of these approaches resulted in peroneal nerve injury. Additionally, the surgeon can decrease this risk by repairing the meniscal tissue using the all-inside meniscal device in the safe zone area.

A topographical and physiological exploration of C-tactile afferents and their response to menthol and histamine

Unmyelinated tactile (C-tactile or CT) afferents are abundant in arm hairy skin and have been suggested to signal features of social affective touch. Here, we recorded from unmyelinated low-threshold mechanosensitive afferents in the peroneal and radial nerves. The most distal receptive fields were located on the proximal phalanx of the third finger for the superficial branch of the radial nerve and near the lateral malleolus for the peroneal nerve. We found that the physiological properties with regard to conduction velocity and mechanical threshold, as well as their tuning to brush velocity, were similar in CT units across the antebrachial (n = 27), radial (n = 8), and peroneal (n = 4) nerves. Moreover, we found that although CT afferents are readily found during microneurography of the arm nerves, they appear to be much more sparse in the lower leg compared with C-nociceptors. We continued to explore CT afferents with regard to their chemical sensitivity and found that they could not be activated by topical application to their receptive field of either the cooling agent menthol or the pruritogen histamine. In light of previous studies showing the combined effects that temperature and mechanical stimuli have on these neurons, these findings add to the growing body of research suggesting that CT afferents constitute a unique class of sensory afferents with highly specialized mechanisms for transducing gentle touch.

NEW & NOTEWORHY Unmyelinated tactile (CT) afferents are abundant in arm hairy skin and are thought to signal features of social affective touch. We show that CTs are also present but are relatively sparse in the lower leg compared with C-nociceptors. CTs display similar physiological properties across the arm and leg nerves. Furthermore, CT afferents do not respond to the cooling agent menthol or the pruritogen histamine, and their mechanical response properties are not altered by these chemicals.

An Update on Peroneal Nerve Entrapment and Neuropathy

Peroneal neuropathy is the most common compressive neuropathy of the lower extremity. It should be included in the differential diagnosis for patients presenting with foot drop, the pain of the lower extremity, or numbness of the lower extremity. Symptoms of peroneal neuropathy may occur due to compression of the common peroneal nerve (CPN), superficial peroneal nerve (SPN), or deep peroneal nerve (DPN), each with different clinical presentations. The CPN is most commonly compressed by the bony prominence of the fibula, the SPN most commonly entrapped as it exits the lateral compartment of the leg, and the DPN as it crosses underneath the extensor retinaculum. Accurate and timely diagnosis of any peroneal neuropathy is important to avoid progression of nerve injury and permanent nerve damage. The diagnosis is often made with physical exam findings of decreased strength, altered sensation, and gait abnormalities. Motor nerve conduction studies, electromyography studies, and diagnostic nerve blocks can also assist in diagnosis and prognosis. First-line treatments include removing anything that may be causing external compression, providing stability to unstable joints, and reducing inflammation. Although many peroneal nerve entrapments will resolve with observation and activity modification, surgical treatment is often required when entrapment is refractory to these conservative management strategies. Recently, additional options including microsurgical decompression and percutaneous peripheral nerve stimulation have been reported; however, large studies reporting outcomes are lacking.

The Danger Zone for Iatrogenic Neurovascular Injury in All-Inside Lateral Meniscal Repair in Relation to the Popliteal Tendon: An MRI Study

Background:

Lateral meniscal repair can endanger the nearby neurovascular structure (peroneal nerve or popliteal artery). To our knowledge, there have been no studies to evaluate the danger zone of all-inside meniscal repair through the anteromedial (AM) and anterolateral (AL) portals in relation to the medial and lateral edges of the popliteal tendon (PT).

Purpose:

To establish the risk of neurovascular injury and the danger zone in repairing the lateral meniscus in relation to the medial and lateral edges of the PT.

Study Design:

Descriptive laboratory study.

Methods:

Using axial magnetic resonance imaging (MRI) studies at the level of the lateral meniscus, lines were drawn to simulate a straight, all-inside meniscal repair device, drawn from the AM and AL portals to both the medial and lateral edges of the PT. In cases in which the line passed through the neurovascular structure, a risk of iatrogenic neurovascular injury was deemed, and measurements were made to determine the danger zones of neurovascular injury in relation to the medial or lateral edges of the PT.

Results:

Axial MRI images of 240 adult patients were reviewed retrospectively. Repairing the body of the lateral meniscus through the AM portal had a greater risk of neurovascular injury than repairs made through the AL portal in relation to the medial edge of the PT (P = .006). The danger zone in repairing the lateral meniscus through the AM portal extended 1.82 ± 1.68 mm laterally from the lateral edge of the PT and 3.13 ± 2.45 mm medially from the medial edge of the PT. Through the AL portal, the danger zone extended 2.81 ± 1.94 mm laterally from the lateral edge of the PT and 1.39 ± 1.53 mm medially from the medial edge of the PT.

Conclusion:

Repairing the lateral meniscus through either the AM or the AL portals in relation to the PT can endanger the peroneal nerve or popliteal artery.

Clinical Relevance:

The surgeon can minimize the risk of iatrogenic neurovascular injury in lateral meniscal repair by avoiding using the all-inside meniscal device in the danger zone area as described in this study.

Proximal fibular nerve conduction studies to tibialis anterior: Optimal E2 (reference electrode) placement

BACKGROUND

Several E2 (reference electrode) positions are described for fibular (peroneal) nerve conduction studies to tibialis anterior (TA).

METHODS

This study compared the contribution of different E2 sites to the TA motor response, using remote referential recordings and different bipolar montages.

RESULTS

The medial knee contributes minimal electrical activity to the bipolar TA recordings, whereas tibial, ankle, and toe references resulted in very similar, moderate amplitude contributions consistent with far field potentials. These observations were very similar in controls and in patients with lower leg symptoms and signs.

CONCLUSIONS

Standard montages using distal leg or foot E2 sites result in lower amplitudes with distortion arising from the E2 electrode, compared with the TA-Knee montage. Optimal measurement of the TA motor response is achieved using a medial knee reference, without compromising measures of fibular nerve conduction across the knee.

Integrative Review of Lower Extremity Nerve Injury During Vaginal Birth

OBJECTIVE

To describe the incidence, health effects, risk factors, and practice implications of lower extremity nerve injury (LENI) related to vaginal births.

DATA SOURCES

We searched MEDLINE, CINAHL, and PubMed from 2000 to 2020 for peer-reviewed published case reports and research studies of LENI related to vaginal births.

STUDY SELECTION

We identified 188 potential records, and 20 met inclusion criteria (six research studies and 14 case studies).

DATA EXTRACTION

Three independent reviewers extracted details of injuries and births into an Excel spreadsheet and analyzed data using SPSS.

DATA SYNTHESIS

Using birth data from each case study and from four of the six research articles, we found the incidence of LENI in vaginal births was 0.3% to 1.8%. The description of health effects includes affected nerves and the location, description, and duration of symptoms. Analyses of risk factors were limited by missing birth data (length of second stage, birth weight, etc). Vaginal births with LENI were 76% spontaneous, 77% with neuraxial anesthesia, and 64% first vaginal birth. Practice implications focused on prevention through specific positioning strategies. Despite nurses being the primary caregivers during labor, LENI was reported most often in anesthesia journals with virtually no reports in nursing journals.

CONCLUSION

LENI is a potential complication of vaginal birth, and little published research is available on prevention and prognosis. While obstetric and anesthesia factors can cause or contribute to nerve injury, LENI is usually caused by positioning and is considered preventable. Care recommendations include the following: avoid prolonged hyperflexion of women's thighs and knees; minimize time in lithotomy, squatting, or kneeling positions; prevent hand or other deep pressure on lateral knee and posterior thigh areas; avoid motor-blocking neuraxial (epidural) anesthesia; and implement frequent repositioning. The paucity of literature contributes to the lack of awareness of LENI among clinicians.

Hydrodissection as a therapeutic and diagnostic modality in treating peroneal nerve compression

A 51-year-old man presented with pain in the region of his left patellar tendon and fibular head. He had previously undergone three L5 epidural steroid injections and physical therapy without relief. Prior magnetic resonance imaging was significant only for fat pad impingement, and electromyography and nerve conduction studies were negative. Ultrasound demonstrated an enlarged peroneal nerve suggestive of peroneal nerve entrapment. Three ultrasound-guided hydrodissection procedures offered symptomatic improvement and identified an area posterior to the fibular head that was unable to be hydrodissected, indicating scar tissue causing peroneal nerve compression. The patient was referred for peroneal nerve decompression at the area of entrapment with complete symptom relief. This case is unique in describing the ability of hydrodissection to identify nerve compression not visualized with other diagnostic tests.

Communications between the superficial and deep fibular nerves in the foot: An anatomical and electrophysiological study

INTRODUCTION

The deep fibular sensory nerve can be recorded to evaluate for peripheral nerve injury; however, it can be challenging in some individuals. Anatomic variation could account for some of this difficulty. Cadaver dissection and electrophysiological testing were used to characterize deep and superficial fibular sensory nerve supply to the foot.

MATERIALS AND METHODS

Nineteen feet from 15 (8 males and 7 females) cadavers were dissected to identify the deep fibular nerves (DFNs) and superficial fibular nerves (SFNs). Sensation to the first dorsal web space was tested electrophysiologically in 101 participants (31 males and 70 females) with an age range of 18-47 years with stimulation over both DFNs and SFNs.

RESULTS

Eleven of the 19 (58%) cadaver limbs had a communication between SFNs and DFNs in the dorsum of the foot. A reliable sensory response was recorded in the first dorsal web space in 88% of the limbs tested. Deep fibular stimulation alone produced a response in 34% of the limbs, while superficial fibular stimulation alone produced a response in 10% of the limbs. A separate response with stimulation of both the DFNs and SFNs was recorded in 44% of the limbs.

CONCLUSIONS

A functional superficial to deep fibular sensory communication is present in a significant portion of the population. Those with the communication may not have the isolated sensory loss that would be expected in the first dorsal web space in conditions impacting the DFNs.

Adductor canal block: Effect of volume of injectate on sciatic extension

Context:

Spread of local anesthetic within adductor canal to peroneal and tibial nerves is described in literature. This spread could be volume-dependent.

Aims:

In this study, we compared the diffusion of two volumes of 0.375% ropivacaine to popliteal fossa.

Settings and Design:

This was a prospective, randomized controlled, single-blind study conducted in Kassab Orthopaedic Institute of Tunis for 1 year (2018).

Materials and Methods:

A total of 42 patients, American Society of Anesthesiologists I/II scheduled for knee arthroscopy under spinal anesthesia scheduled to receive adductor canal block, were randomized into two groups: group N received 20 mL of ropivacaine 0.375% and group H received 40 mL. We evaluated sensory motor blocks of both peroneal and tibial nerves at 30 and 60 min.

Statistical Analysis Used:

Chi-square or Fisher's exact test was used to compare the number and percentage. P <0.05 was significant.

Results:

At 60 min, complete sensory block of the peroneal nerve was obtained for 16 patients in group H versus 15 patients in group N with no statistically significant difference (P = 0.60). The difference was also not significant (P = 0.27) for the tibial nerve: 14 patients for group H versus 16 for group N. Motor blockade was rare in the two nerve territories.

Conclusion:

Spread of 0.375% ropivacaine to popliteal fossa resulted in high rate of complete sensory blockade of both peroneal and tibial nerves. Diffusion of local anesthetic was not volume-dependent.

Rationale and design of the theRapeutic effects of peroneal nerve functionAl electrical stimuLation for Lower extremitY in patients with convalescent poststroke hemiplegia (RALLY) study: study protocol for a randomised controlled study

INTRODUCTION

Increasing evidence supports the utilisation of functional electrical stimulation (FES) to improve gait following stroke; however, few studies have focused exclusively on its use in the convalescent phase. In addition, its efficacy in patients with a non-Western life style has not been evaluated.

METHODS AND ANALYSIS

This is a randomised, controlled, open-label multicentre study, comparing rehabilitation with and without FES. The purpose of our study is to test the hypothesis that the FES system improves walking ability in Japanese patients with hemiplegia during the convalescent phase. Two hundred patients aged 20-85 years who had an initial stroke ≤6 months prior to the enrolment, are in a convalescent phase (after the end of acute phase treatment, within 6 months after the onset of stroke) with functional ambulation classification 3 or 4 and have a hemiplegic gait disorder (drop foot) due to stroke have been recruited from 21 institutions in Japan. The patients are randomised in 1:1 fashion to usual gait rehabilitation or rehabilitation using FES (Walkaide). The trial duration is 8 weeks, and the primary outcome measured will be the change in maximum distance from baseline to the end of the trial, as measured with the 6 min walk test (6-MWT). The 6-MWT is performed barefoot, and the two treatment groups are compared using the analysis of covariance.

ETHICS AND DISSEMINATION

This study is conducted in accordance with the principles of the Declaration of Helsinki and the Ethical Guidelines for Medical and Health Research Involving Human Subjects and is approved by the ethics committee of all participating institutions. The published results will be disseminated to all the participants by the study physicians.

TRIAL REGISTRATION NUMBER

The University Hospital Medical Information Network-Clinical Studies Registry (UMIN000020604).

Peroneal nerve palsy caused by a synovial cyst of the proximal tibiofibular joint: a report of two cases and review of the literature

Synovial cyst of the proximal tibiofibular joint is a very rare condition, for which there is no consensus regarding treatment. Two macroscopic forms may be encountered: extraneural cysts and intraneural cysts. We present the cases of two patients who had synovial cysts of proximal tibiofibular joint that caused peroneal nerve palsy. We discussed the special features of synovial cysts and reviewed the literature. We considered the best treatment of synovial cysts originating from proximal tibiofibular joint and causing peroneal nerve palsy to be a total surgical removal as soon as possible after the diagnosis is made. However, follow-up is needed because recurrence is possible. It should be kept in mind that despite surgical treatment the neurological symptoms may not recover.

Acute bilateral drop foot as a complication of prolonged squatting due to haemorrhoid

Drop foot is defined as difficulty of dorsiflexion of the foot and ankle due to weak anterior tibial, extensor hallucis longus and extensor digitorum longus muscles. Cauda equina syndrome, local peroneal nerve damage due to trauma, nerve entrapment, compartment syndrome and tumors are common etiologies. A 32-year-old male patient was applied with difficulty in dorsiflexion of both of his toes, feet and ankles after he had squatted in toilette for 6-7 hours (because of his haemorrhoid) after intense alcohol intake 2 weeks before. Acute, partial, demyelinating lesion in head of fibula segment of peroneal nerves was diagnosed by electromyography. This case was reported since prolonged squatting is an extremely rare cause of acute bilateral peroneal neuropathy. This type of neuropathy is mostly demyelination and has good prognosis with physical therapy and mechanical devices, but surgical intervention may be required due to axonal damage. People such as workers and farmers working in the squatting position for long hours should be advised to change their position as soon as the compression symptoms (numbness, tingling) appear.

The Position of the Popliteal Artery and Peroneal Nerve Relative to the Menisci in Children: A Cadaveric Study

Background:

Meniscal injury in skeletally immature patients is increasingly reported. During meniscal repair, all-inside devices may protrude beyond the posterior limits of the meniscus, putting the neurovascular structures at risk.

Purpose:

The purposes of this study were (1) to examine the relationship between the popliteal artery and the posterolateral and posteromedial aspects of the menisci, (2) to examine the relationship of the peroneal nerve to the posterolateral meniscus, and (3) to develop recommendations for avoiding neurovascular injury during posterior meniscal repair in pediatric patients.

Study Design:

Descriptive laboratory study.

Methods:

A total of 26 skeletally immature knee cadaveric specimens (7 females and 19 males) were included. Specimens were divided into age groups: 2-4, 5-8, and 9-11 years. The most posterior extent of the lateral and medial menisci was identified via sagittal and axial views on computed tomography (CT) scans. The shortest distance from the most posterior aspect of the lateral and medial menisci to the popliteal artery and the shortest distance from the posterior aspect of the lateral menisci to the anterior rim of the peroneal nerve were measured, and 3-dimensional models of representative specimens were re-created through use of CT scans.

Results:

For the age groups 2-4, 5-8, and 9-11 years, the mean minimum distance from the posterolateral meniscus to the popliteal artery was 5.2, 6.7, and 8.2 mm, respectively, and the mean minimum distance from the posteromedial meniscus to the popliteal artery was 12.7, 15.4, and 20.3 mm, respectively. In all groups, the distance between the posteromedial meniscus and the popliteal artery was greater than that between the posterolateral meniscus and the popliteal artery. The mean distance from the peroneal nerve to the lateral meniscus was 13.3, 15.0, and 17.9 mm for the respective groups.

Conclusion:

Many all-inside meniscal repair devices have sharp tips that penetrate posterior to the meniscus and capsule. This study demonstrated that the distance between the posterior meniscus and popliteal artery is relatively small in pediatric patients, especially for the lateral meniscus region.

Clinical Relevance:

Because of the higher potential for meniscal healing, meniscal repair is more likely to be performed in pediatric patients. The data in this study regarding the proximity of the lateral meniscus and neurovascular structures may be used to guide safe surgical repair of posterior meniscal tears during the use of all-inside meniscal repair devices in these patients.

Clinical outcome after decompression of intraneural peroneal ganglion cyst and its morphologic correlation to postoperative nerve ultrasound

OBJECTIVE

Intraneural ganglion cysts are rare and benign mucinous lesions that affect peripheral nerves, most frequently the common peroneal nerve (CPN). The precise pathophysiological mechanisms of intraneural ganglion cyst development remain unclear. A well-established theory suggests the spread of mucinous fluid along the articular branch of the peroneal nerve as the underlying mechanism. Clinical outcome following decompression of intraneural ganglion cysts has been demonstrated to be excellent. The aim of this study was to evaluate the correlation between clinical outcome and ultrasound-detected morphological nerve features following decompression of intraneural ganglion cysts of the CPN.

METHODS

Data were retrospectively analyzed from 20 patients who underwent common peroneal nerve ganglion cyst decompression surgery at the Universität Ulm/Günzburg Neurosurgery Department between October 2003 and October 2017. Postoperative clinical outcome was evaluated by assessment of the muscular strength of the anterior tibial muscle, the extensor hallucis longus muscle, and the peroneus muscle according to the Medical Research Council grading system. Hypesthesia was measured by sensation testing. In all patients, postoperative morphological assessment of the peroneal nerve was conducted between October 2016 and October 2017 using the iU22 Philips Medical ultrasound system at the last routine follow-up appointment. Finally, the correlations between morphological changes in nerve ultrasound and postoperative clinical outcomes were evaluated.

RESULTS

During the postoperative ultrasound scan an intraneural hypoechogenic ring structure located at the medial side of the peroneal nerve was detected in 15 (75%) of 20 patients, 14 of whom demonstrated an improvement in motor function. A regular intraneural fasicular structure was identified in 3 patients (15%), who also reported recovery. In 1 patient, a recurrent cyst was detected, and 1 patient showed intraneural fibrosis for which recovery did not occur in the year following the procedure. Two patients (10%) developed neuropathic pain that could not be explained by nerve ultrasound findings.

CONCLUSIONS

The results of this study demonstrate significant recovery from preoperative weakness after decompression of intraneural ganglion cysts of the CPN. A favorable clinical outcome was highly correlated with an intraneural hypoechogenic ring-shaped structure on the medial side of the CPN identified during a follow-up postoperative ultrasound scan. These study results indicate the potential benefit of ultrasound scanning as a prognostic tool following decompression procedures for intraneural ganglion cysts of the CPN.

The effects of knee joint angle on neuromuscular activity during electrostimulation in healthy older adults

Introduction

Electrostimulation devices stimulate the common peroneal nerve, producing a calf muscle-pump action to promote venous circulation. Whether knee joint angle influences calf neuromuscular activity remains unclear. Our aim was to determine the effects of knee joint angle on lower limb neuromuscular activity during electrostimulation.

Methods

Fifteen healthy, older adults underwent 60 min of electrostimulation, with the knee joint at three different angles (0°, 45° or 90° flexion; random order; 20 min each). Outcome variables included electromyography of the peroneus longus, tibialis anterior and gastrocnemius medialis and lateralis and discomfort.

Results

Knee angle did not influence tibialis anterior and peroneus longus neuromuscular activity during electrostimulation. Neuromuscular activity was greater in the gastrocnemius medialis (p = 0.002) and lateralis (p = 0.002) at 90°, than 0° knee angle. Electrostimulation intensity was positively related to neuromuscular activity for each muscle, with a knee angle effect for the gastrocnemius medialis (p = 0.05).

Conclusion

Results suggest that during electrostimulation, knee joint angle influenced gastrocnemii neuromuscular activity; increased gastrocnemius medialis activity across all intensities (at 90°), when compared to 0° and 45° flexion; and did not influence peroneus longus and tibialis anterior activity. Greater electrostimulation-evoked gastrocnemii activity has implications for producing a more forceful calf muscle-pump action, potentially further improving venous flow.

Peripheral Nerve Injury to the Lower Limb: Repair and Secondary Reconstruction

This article is based on literature review of relevant articles as well as the authors’ own experiences in treating peripheral nerve injuries of the lower limb. The article deals with causative factors of lower limb nerve injuries, various grading systems of the injuries, approaches to such injuries, and techniques to repair lower limb nerve injuries. It also enumerates several reasons to explain the poorer prognosis of peroneal nerve injuries and the possible distal nerve transfers in lower limb albeit with poorer outcomes.

The anatomic location and importance of the tibialis posterior fascicular bundle at the sciatic nerve bifurcation: report of 3 cases

The authors present the cases of 3 patients with severe injuries affecting the peroneal nerve combined with loss of tibialis posterior function (inversion) despite preservation of other tibial nerve function. Loss of tibialis posterior function is problematic, since transfer of the tibialis posterior tendon is arguably the best reconstructive option for foot drop, when available. Analysis of preoperative imaging studies correlated with operative findings and showed that the injuries, while predominantly to the common peroneal nerve, also affected the lateral portion of the tibial nerve/division near the sciatic nerve bifurcation. Sunderland's fascicular topographic maps demonstrate the localization of the fascicular bundle subserving the tibialis posterior to the area that corresponds to the injury. This has clinical significance in predicting injury patterns and potentially for treatment of these injuries. The lateral fibers of the tibial division/nerve may be vulnerable with long stretch injuries. Due to the importance of tibialis posterior function, it may be important to perform internal neurolysis of the tibial division/nerve in order to facilitate nerve action potential testing of these fascicles, ultimately performing split nerve graft repair when nerve action potentials are absent in this important portion of the tibial nerve.

Diagnostic value of ultrasonography in peroneal neuropathy

Background/aim

Peroneal neuropathy at the fibular head (PNFH) is one of the most common entrapment neuropathies. Our aim in this study was to analyze the efficiency of ultrasonography in the diagnosis of PNFH.

Materials and methods

The study included 15 peroneal nerves of 12 patients with PNFH and 24 peroneal nerves of 12 healthy controls. PNFH confirmation was based on clinical and electrophysiological findings. All patients and controls underwent ultrasonographic evaluations for peroneal nerves. The cross-sectional area (CSA) was measured. Echogenicity of the nerve was evaluated by comparing it with the adjacent connective tissue deep under the subcutaneous fat.

Results

CSA measurement of the peroneal nerve is a valuable diagnostic tool in predicting PNFH (AUC: 0.87, 95% CI: 0.73–1.00, P < 0.01). The CSA cutoff value for diagnosing PNFH was found to be 0.115 cm 2 with 80% sensitivity and 99% specificity. Hypoechoic peroneal nerve in patients with PNFH was very frequent.

Conclusion

Ultrasonography is a useful technique in diagnosing PNFH. In addition to clinic and electrophysiological findings, it may improve diagnostic performance.

Bilateral Common Peroneal Nerve Entrapment After Excessive Weight Loss: Case Report and Review of the Literature

We report a case of excessive weight loss causing bilateral common peroneal nerve entrapment in a 60-year-old patient. The bilateral peroneal involvement suggested a systemic cause. Excessive weight loss during a relatively short period can cause changes in the tissues surrounding the common peroneal nerve and lead to its entrapment in the peroneal tunnel. Our patient underwent successful surgical decompression with significant improvement.

Effects of transcutaneous electrical nerve stimulation via peroneal nerve or soleus muscle on venous flow: A randomized cross-over study in healthy subjects

BACKGROUND

Transcutaneous electrical nerve stimulation (TENS) is used to prevent venous stasis and thromboembolism. However, best electrostimulation parameters have yet to be established. The aim of the study was to compare the hemodynamic effects and the participants' relative discomfort of 3 TENS sequences at the maximum tolerated intensity stimulus.

METHODS

Twenty-four healthy university students (50% male) participated in a cross-over, randomized study. Each participant received 2 TENS sequences on peroneal nerve at 1 and 5 Hz, and the third one on soleus muscle at 5 Hz. Popliteal flow volume (FV) and peak velocity (PV) were measured using Doppler ultrasound and the relative change from basal values was recorded. Discomfort questionnaires -visual analogue scale (VAS) and verbal rating scale (VRS)- were also administered to compare sensations among the three applications.

RESULTS

All interventions produced significant hemodynamic responses compared to baseline. Both 5 Hz applications obtained higher FV increments than 1 Hz TENS (P < .001). The muscle application resulted in the lowest PV increment (P < .001). TENS at 5 Hz on nerve location was the worst tolerated, with higher values in VRS (P = .056) and VAS (P = .11), although not significant.

CONCLUSION

TENS at 5 Hz on soleus site may be the most appropriate protocol for enhancing venous return.

An Anatomical Study of Nerves at Risk During Minimally Invasive Hallux Valgus Surgery

The growing popularity of minimally invasive surgical (MIS) procedures makes it necessary that new anatomical references arise, to aid in tridimensional orientation and localization of structures that are not directly visible to the surgeon. This is especially critical for structures at risk like nerves or blood vessels. Optimization of the handling of cadaveric material and the combination of multiple techniques compensate for the limited availability of adequate specimens. The described protocol combines anatomical plane-by-plane dissection and sectional anatomy of fresh-frozen specimens to help localize relevant structures, such as nerves, arteries, veins and to correctly position the portals during MIS procedures. Depiction of these structures in anatomy textbooks can differ from what is encountered in the surgical field; and for this reason, new anatomical studies with a surgical orientation are needed. However, this is a complex, time-consuming technique requiring specific training. The anatomical references described with the so-called 'clock method' provide the surgeon with an easy and reproducible system to locate the path of the nerves at risk in Hallux Valgus MIS procedures. This model can be extrapolated to many other minimally invasive surgical procedures.

Distal peroneal nerve decompression after sciatic nerve injury secondary to total hip arthroplasty

OBJECTIVE The sciatic nerve, particularly its peroneal division, is at risk for injury during total hip arthroplasty (THA), especially when a posterior approach is used. The majority of the morbidity results from the loss of peroneal nerve-innervated muscle function. Approximately one-third of patients recover spontaneously. The objectives of this study were to report the outcomes of distal decompression of the peroneal nerve at the fibular tunnel following sciatic nerve injury secondary to THA and to attempt to identify predictors of a positive surgical outcome. METHODS A retrospective study of all patients who underwent peroneal decompression for the indication of sciatic nerve injury following THA at the Mayo Clinic or Washington University School of Medicine in St. Louis was performed. Patients with less than 6 months of postoperative follow-up were excluded. The primary outcome was dorsiflexion strength at latest follow-up. Univariate and multivariate logistic regression analyses were performed to assess the ability of the independent variables to predict a good surgical outcome. RESULTS The total included cohort consisted of 37 patients. The median preoperative dorsiflexion grade at the time of peroneal decompression was 0. Dorsiflexion at latest follow-up was Medical Research Council (MRC) ≥ 3 for 24 (65%) patients. Dorsiflexion recovered to MRC ≥ 4- for 15 (41%) patients. In multivariate logistic regression analysis, motor unit potentials in the tibialis anterior (OR 19.84, 95% CI 2.44-364.05; p = 0.004) and in the peroneus longus (OR 8.68, 95% CI 1.05-135.53; p = 0.04) on preoperative electromyography were significant predictors of a good surgical outcome. CONCLUSIONS After performing peroneal nerve decompression at the fibular tunnel, 65% of the patients in this study recovered dorsiflexion strength of MRC ≥ 3 at latest follow-up, potentially representing a significant improvement over the natural history.

Neurofibroma of the peroneal nerve

Neurofibromas are benign tumors composed of different cell types from the peripheral nervous system. Neurofibromas infiltrate between nerve fascicles and do not have a discrete capsule. On MRI, they are T1 hypointense or isointense, T2 hyperintense, often with a "target sign," and contrast enhancing. The video shows gross-total resection of a peroneal nerve neurofibroma presenting as a painful mass in the popliteal fossa. Incisions across a skin crease can be either oblique or zigzag, but never perpendicular to it. It is also key to expose normal nerve proximal and distal to the tumor. The patient had a good functional outcome. The video can be found here: https://youtu.be/G74Zoa1Y2JM .

Intraneural perineuriomas: diagnostic value of magnetic resonance neurography

Intraneural perineurioma (IP) is an under-recognized hypertrophic peripheral nerve tumor. It affects young patients involving frequently the sciatic nerve and its branches and presents with a progressive, painless and predominantly motor deficit. Magnetic resonance neurography (MRN) is a useful tool to localize the lesion, evaluate its extension, and discriminate between different etiologies. We reviewed the clinical records of 11 patients with pathologically confirm IP. Eight patients were males with mean age 19 years. Initial complains were unilateral steppage (seven patients), bilateral steppage (one patient), unilateral gastrocnemius wasting (one patient), unilateral thigh atrophy (one patient), and unilateral hand weakness (one patient). Nine patients had mild painless sensory loss. Examinations revealed involvement of sciatic nerve extending into the peroneal nerve (eight patients), posterior tibial nerve (one patient), radial nerve (one patient), and femoral nerve (one patient). MRN revealed enlargement of the affected nerve isointense on T1-weighted, hyperintense on T2 fat-saturated images, and with avid enhancement on post-contrast imaging. In all patients, a nerve biopsy confirmed the diagnosis. MRN allows early and non-invasive identification of this tumor and is a key tool providing localization and differential diagnosis in patients with slowly progressive focal neuropathies.

Characterisation and functional mapping of surface potentials in the rat dorsal column nuclei

KEY POINTS

The brainstem dorsal column nuclei (DCN) process sensory information arising from the body before it reaches the brain and becomes conscious. Despite significant investigations into sensory coding in peripheral nerves and the somatosensory cortex, little is known about how sensory information arising from the periphery is represented in the DCN. Following stimulation of hind-limb nerves, we mapped and characterised the evoked electrical signatures across the DCN surface. We show that evoked responses recorded from the DCN surface are highly reproducible and are unique to nerves carrying specific sensory information.

ABSTRACT

The brainstem dorsal column nuclei (DCN) play a role in early processing of somatosensory information arising from a variety of functionally distinct peripheral structures, before being transmitted to the cortex via the thalamus. To improve our understanding of how sensory information is represented by the DCN, we characterised and mapped low- (<200 Hz) and high-frequency (550-3300 Hz) components of nerve-evoked DCN surface potentials. DCN surface potentials were evoked by electrical stimulation of the left and right nerves innervating cutaneous structures (sural nerve), or a mix of cutaneous and deep structures (peroneal nerve), in 8-week-old urethane-anaesthetised male Wistar rats. Peroneal nerve-evoked DCN responses demonstrated low-frequency events with significantly longer durations, more high-frequency events and larger magnitudes compared to responses evoked from sural nerve stimulation. Hotspots of low- and high-frequency DCN activity were found ipsilateral to stimulated nerves but were not symmetrically organised. In conclusion, we find that sensory inputs from peripheral nerves evoke unique and characteristic DCN activity patterns that are highly reproducible both within and across animals.

Pain Relief and Health-Related Quality-of-Life Improvement After Microsurgical Decompression of Entrapped Peripheral Nerves in Patients With Painful Diabetic Peripheral Neuropathy

Surgery had been shown to be effective for superimposed peripheral nerve entrapment syndrome in patients with diabetic peripheral neuropathy (DPN), with pain relief and sensation restored. Few studies, however, have reported the quality-of-life outcomes of surgery for the treatment of painful DPN (PDPN). The objective of the present study was to evaluate the effects of microsurgical decompression of multiple entrapped peripheral nerves on pain and health-related quality of life in patients with refractory PDPN of the lower limbs. Eleven patients with intractable PDPN of the lower limbs were recruited for the present study. All the patients underwent microsurgical decompression of the common peroneal nerve, deep peroneal nerve, and posterior tibial nerve. The pain intensity was assessed using the visual analog scale and health-related quality of life was measured using the short-form 36-item quality-of-life survey. Six (54.6%) patients experienced >50% pain relief (both daytime pain and nocturnal pain) at 2 weeks after the decompression procedure and 8 (72.7%) patients at 24 months postoperatively. Two (18.2%) patients experienced a >50% decrease in peak pain at the 2 weeks after the procedure and 8 (72.7%) patients at 24 months. Additionally, the scores from the short-form 36-item quality-of-life survey were significantly improved in the following 2 domains: bodily pain and general health at 2 weeks after the decompression procedure. Also, at 24 months postoperatively, 6 domains had significantly improved, including physical function, bodily pain, general health, social function, role emotional, and mental health. No significant side effects were recorded during the study. Microsurgical decompression of peripheral nerves is an effective and safe therapy for intractable PDPN with superimposed nerve compression.

Diabetic neuropathy increases stimulation threshold during popliteal sciatic nerve block

BACKGROUND

Peripheral nerve stimulation is commonly used for nerve localization in regional anaesthesia, but recommended stimulation currents of 0.3-0.5 mA do not reliably produce motor activity in the absence of intraneural needle placement. As this may be particularly true in patients with diabetic neuropathy, we examined the stimulation threshold in patients with and without diabetes.

METHODS

Preoperative evaluation included a neurological exam and electroneurography. During ultrasound-guided popliteal sciatic nerve block, we measured the current required to produce motor activity for the tibial and common peroneal nerve in diabetic and non-diabetic patients. Proximity to the nerve was evaluated post-hoc using ultrasound imaging.

RESULTS

Average stimulation currents did not differ between diabetic (n=55) and non-diabetic patients (n=52). Although the planned number of patients was not reached, the power goal for the mean stimulation current was met. Subjects with diminished pressure perception showed increased thresholds for the common peroneal nerve (median 1.30 vs. 0.57 mA in subjects with normal perception, P=0.042), as did subjects with decreased pain sensation (1.60 vs. 0.50 mA in subjects with normal sensation, P=0.038). Slowed ulnar nerve conduction velocity predicted elevated mean stimulation current (r=-0.35, P=0.002). Finally, 15 diabetic patients required more than 0.5 mA to evoke a motor response, despite intraneural needle placement (n=4), or required currents ≥2 mA despite needle-nerve contact, vs three such patients (1 intraneural, 2 with ≥2 mA) among non-diabetic patients (P=0.003).

CONCLUSIONS

These findings suggest that stimulation thresholds of 0.3-0.5 mA may not reliably determine close needle-nerve contact during popliteal sciatic nerve block, particularly in patients with diabetic neuropathy.

CLINICAL TRIAL REGISTRATION

NCT01488474.

Outcomes of the Bridle Procedure for the Treatment of Foot Drop

BACKGROUND

The purpose of this study was to determine the clinical outcomes and objective measures of function that can be expected for patients following the Bridle procedure (modification of the posterior tibial tendon transfer) for the treatment of foot drop.

METHODS

Nineteen patients treated with a Bridle procedure and 10 matched controls were evaluated. The Bridle group had preoperative and 2-year postoperative radiographic foot alignment measurements and completion of the Foot and Ankle Ability Measure. At follow-up, both groups were tested for standing balance (star excursion test) and for ankle plantarflexion and dorsiflexion isokinetic strength, and the American Orthopaedic Foot & Ankle Society and Stanmore outcome measures were collected only on the Bridle patients.

RESULTS

There was no change in radiographic foot alignment from pre- to postoperative measurement. Foot and Ankle Ability Measure subscales of activities of daily living and sport, American Orthopaedic Foot & Ankle Society, and Stanmore scores were all reduced in Bridle patients as compared with controls. Single-limb standing-balance reaching distance in the anterolateral and posterolateral directions were reduced in Bridle participants as compared with controls (P < .03). Isokinetic ankle dorsiflexion and plantarflexion strength was lower in Bridle participants (2 ± 4 ft·lb, 44 ± 16 ft·lb) as compared with controls (18 ± 13 ft·lb, 65 ± 27 ft·lb, P < .02, respectively). All Bridle participants reported excellent to good outcomes and would repeat the operation. No patient wore an ankle-foot orthosis for everyday activities.

CONCLUSION

The Bridle procedure was a successful surgery that did not restore normal strength and balance to the foot and ankle but allowed individuals with foot drop and a functional tibialis posterior muscle to have significantly improved outcomes and discontinue the use of an ankle-foot orthosis. In addition, there was no indication that loss of the normal function of the tibialis posterior muscle resulted in change in foot alignment 2 years after surgery.

LEVEL OF EVIDENCE

Level III, retrospective comparative series.

Repetitive Plantar Flexion (Provocation) Test for the Diagnosis of Intermittent Claudication due to Peroneal Nerve Entrapment Neuropathy: Case Report

The diagnosis of peroneal nerve (PN) entrapment neuropathy (PNEN) is based on clinical symptoms and nerve conduction studies. However, these studies do not always detect PNEN. Our 64-year-old patient suffered persistent left L5 numbness after two lumbar surgeries. Two years before admission to our institute his left leg pain gradually reappeared. When walking, his numbness in the left lower thigh to the dorsum of the foot increased. Electrophysiological testing revealed no conduction block on the PN. To identify the origin of his intermittent symptoms we performed loading of repetitive ankle plantar flexion in the at-rest posture to avoid the lumbar factor. We used this provocation test to check for PNEN because it occurs at a site where the PN passes the soleus- and the peroneus longus muscle (SM, PLM). The symptoms appeared reproducibly within 10 s of loading. PN neurolysis under local anesthesia showed that the PN was strongly compressed by the SM and PLM. This procedure eased his symptoms and he was able to walk without elicitation of numbness and pain upon repetitive ankle plantar flexion. In our case, repetitive plantar flexion elicited the symptoms and this provocation test may be useful to identify PN dynamic entrapment neuropathy as the origin of intermittent claudication.

Influence of a fabella in the gastrocnemius muscle on the common fibular nerve in Japanese subjects

The fabella is a sesamoid bone located in the proximal tendon of the gastrocnemius muscle. In rare cases, its presence may lead to a variety of clinical problems, including fabella syndrome and common fibular (CF) nerve palsy. The purpose of this study was to analyze the morphology of the fabella and CF nerve and discuss the influence of any existing fabellae on the size of the CF nerve. The morphology of the fabella and CF nerve in the popliteal region of the lateral head of the gastrocnemius muscle was investigated in 102 knees of 51 Japanese cadavers. The maximum circumference of the thigh, knee, and calf and the frequency, position, and size of the fabella were measured. In addition, the CF nerve width and thickness were measured proximal to the fabellar region and again as the CF nerve passed posterior, lateral, or medial to the region. A fabella was observed in 70 knees (68.6%). The CF nerve adjacent to the fabella was significantly wider and thinner than in the region proximal to the fabella (P < 0.001). In cases in which a bony fabella was present, there was a significant relationship between the thickness of the CF nerve and the circumference of the thigh and knee. The following factors were observed to contribute to the presence of a fabella causing alterations in the size of the CF nerve: a bony fabella, a CF nerve path posterior or lateral to the fabella, and subjects with a thin physique and bony fabella.

Double muscle innervation using end-to-side neurorrhaphy in rats

CONTEXT AND OBJECTIVE

One of the techniques used for treating facial paralysis is double muscle innervation using end-to-end neurorrhaphy with sectioning of healthy nerves. The aim of this study was to evaluate whether double muscle innervation by means of end-to-side neurorrhaphy could occur, with maintenance of muscle innervation.

DESIGN AND SETTING

Experimental study developed at the Experimental Research Center, Faculdade de Medicina de Botucatu, Unesp.

METHODS

One hundred rats were allocated to five groups as follows: G1, control group; G2, the peroneal nerve was sectioned; G3, the tibial nerve was transected and the proximal stump was end-to-side sutured to the intact peroneal nerve; G4, 120 days after the G3 surgery, the peroneal nerve was sectioned proximally to the neurorrhaphy; G5, 120 days after the G3 surgery, the peroneal and tibial nerves were sectioned proximally to the neurorrhaphy.

RESULTS

One hundred and fifty days after the surgery, G3 did not show any change in tibial muscle weight or muscle fiber diameter, but the axonal fiber diameter in the peroneal nerve distal to the neurorrhaphy had decreased. Although G4 showed atrophy of the cranial tibial muscle 30 days after sectioning the peroneal nerve, the electrophysiological test results and axonal diameter measurement confirmed that muscle reinnervation had occurred.

CONCLUSION

These findings suggest that double muscle innervation did not occur through end-to-side neurorrhaphy; the tibial nerve was not able to maintain muscle innervation after the peroneal nerve had been sectioned, although muscle reinnervation was found to have occurred, 30 days after the peroneal nerve had been sectioned.

The effect of functional electrical stimulation on balance function and balance confidence in community-dwelling individuals with stroke

PURPOSE

The purpose of this study was to evaluate the change in balance function and balance confidence in adults with chronic stroke who are starting a gait re-education program with functional electrical stimulation (FES).

METHODS

The study used a before-after study design. Fifteen community-dwelling adults with chronic stroke completed four weekly sessions (2 hours each) of balance and ambulation training with FES applied to the ankle dorsiflexors during the swing phase. Following this familiarization period, participants were assessed for balance and mobility with and without the use of FES. Balance confidence was assessed before and after the familiarization period using the Activities-specific Balance Confidence (ABC) scale.

RESULTS

There was a small but statistically significant improvement in toe clearance and balance function with the FES device, but no detectable change in gait speed. More than half of participants reported reduced balance confidence with the FES device; one-third showed a large (>11 ABC points) reduction in balance confidence.

CONCLUSION

Physical improvements can occur during FES treatment of individuals post-stroke; however, this may be associated with a clinically important impairment in balance confidence as patients with stroke familiarize themselves with FES treatment.

Intraoperative electrophysiological studies to predict the efficacy of neurolysis after nerve injury-experiment in rats

Compound muscle action potentials (CMAPs) can be used to analyze injury and recovery of nerve. This standardized study evaluates the value of CMAP analysis in predicting the long-term efficacy of neurolysis. CMAP amplitude is also used to determine the optimal extent of neurolysis. The left peroneal nerves of 30 rats were crushed. CMAPs were recorded for both crushed (left) and control (right) nerves. Fifteen rats underwent neurolysis 3 months post crush injury; the remaining 15 were sham controls and did not undergo neurolysis. CMAP measurements were taken after: (1) release of the nerve from the fascia, (2) opening the epineurium, and (3) opening the perineurium. At 3 months post crush injury, opening the epineurium resulted in a statistically significant increase in CMAP. CMAP increase with perineurial neurolysis was greater than with fascial release of the nerve but was not statistically different from that of epineurial release. At 5 months post crush injury, recovery of crushed nerves that underwent neurolysis was 90% and significantly less at 70.5% in rats not treated with neurolysis, according to CMAP analysis. Two conclusions can be made from this study. First, intraoperative neurophysiologic studies can monitor the immediate results of neurolysis and predict long-term results in the injured nerve. Second, epineurotomy is important in neurolysis, improves the function of the nerve, less invasive, and a slightly more effective technique than perineurotomy.

Utilization of nerve conduction studies for the diagnosis of polyneuropathy in patients with diabetes: a retrospective analysis of a large patient series

BACKGROUND

Diabetic polyneuropathy (DPN) is a disabling complication of diabetes mellitus. A population-based analysis of physician utilization of nerve conduction studies (NCS) for the assessment of DPN was conducted.

METHODS

All electrodiagnostic encounters over a 30-month period using a computer-based neurodiagnostic instrument linked to a data registry were analyzed retrospectively. The DPN case definition was abnormal sural and peroneal nerve conduction.

RESULTS

The study cohort consisted of a total of 63,779 electrodiagnostic encounters performed by 3468 physician practices. Primary care and internal medicine physicians represented 80.1% of the practices and accounted for 65.7% of the encounters. Endocrinologists represented 4.6% of the practices and 20.1% of the encounters. The demographics of patients were 52.7% female; 63.4+/-11.8 (mean+/-standard deviation) years (age); 168.1+/-10.9 cm (height); 92.2+/-22.6 kg (weight); and 32.6+/-7.2 kg/m(2) (body mass index). The most common peroneal abnormality was F-wave latency (33.6%). The sural nerve response latency and amplitude parameters had similar abnormality rates (58.3 and 62.7%). DPN was identified in 52.6% of the encounters; in another 19.3% no neuropathy was found.

CONCLUSIONS

For over 70% of the patients, the specific diagnostic question of the presence of DPN was addressed by NCS with evidence-based criteria. The demographic features were strongly associated with risk of diabetes and DPN, suggesting that NCS were applied to appropriate demographic subgroups. The rate of DPN was also comparable to levels seen by academic electromyography laboratories. In 32.6% of the encounters the NCS suggested a posttest diagnosis other than DPN. This rate was similar to the results of referral to traditional electromyography laboratories. This study demonstrated that NCS using computer-based electrodiagnostic equipment was a suitable tool for the diagnosis of DPN. Furthermore, this technology permits examination of DPN in large populations.