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Clinical Radiology Mar 2021Morton's neuroma is a commonly encountered cause of forefoot pain, which may limit weight-bearing activities and footwear choices. Although the aetiology and... (Review)
Review
Morton's neuroma is a commonly encountered cause of forefoot pain, which may limit weight-bearing activities and footwear choices. Although the aetiology and pathomechanism of this condition is controversial, the histological endpoint is well established as benign perineural fibrosis of a common plantar digital nerve, typically within the third intermetatarsal space. The diagnosis of Morton's neuroma is mainly based on characteristic symptoms and clinical findings, but may be confirmed by ultrasonography. Although ultrasound is a highly accurate diagnostic tool for Morton's neuroma, it is subject to interoperator variability due to differences in technique and level of experience. In this paper, the authors review the anatomy of the common plantar digital nerves and surrounding structures in the forefoot, which are deemed relevant to the understanding of Morton's neuroma, especially from a sonographic point of view. Several theories of the pathomechanism of Morton's neuroma are briefly discussed. The main purpose of this article is to illustrate the ultrasound techniques for evaluating Morton's neuroma and performing ultrasound-guided corticosteroid injections.
Topics: Diagnostic Imaging; Humans; Metatarsal Bones; Morton Neuroma
PubMed: 33168237
DOI: 10.1016/j.crad.2020.10.006 -
Journal of Plastic, Reconstructive &... Aug 2021The role of the plantar nerve in the pathogenesis of macrodactyly of the foot is unknown. We investigated the distribution of affected toes and forefoot in 27 feet of 26...
The role of the plantar nerve in the pathogenesis of macrodactyly of the foot is unknown. We investigated the distribution of affected toes and forefoot in 27 feet of 26 patients with pedal macrodactyly, and how this relates to innervation of the affected plantar nerve. A preoperative ultrasound examination was performed to determine the diameter and structure of the plantar nerve. Histologic findings were recorded during surgery. The microstructure of affected plantar nerves was evaluated by hematoxylin-eosin staining, while S100 expression was assessed by immunofluorescence analysis. Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) gene mutation in the affected nerve tissue was detected by Sanger DNA sequencing. The affected toes and forefoot involved innervation of the medial plantar nerve in 25/27 feet, the lateral plantar nerve in one foot, and both medial and lateral plantar nerves in one foot. All affected plantar nerves, which were accompanied by a fatty strip, were surrounded by or infiltrated with fat. The affected plantar nerves showed enlargement, a tortuous course, fatty infiltration, or a combination of these. Pathologic changes in affected plantar nerves involved only the epineurium and not the perineurium or endoneurium. Expression of the Schwann cell marker S100 was absent in some areas of affected nerves. Sequencing of PIK3CA exons identified a gain-of-function mutation (p.His1047Arg) in affected plantar nerves. These results indicate that pathologic impairment of the plantar nerve can lead to macrodactyly of the foot, which may be considered as a nerve trunk disease.
Topics: Child; Child, Preschool; Class I Phosphatidylinositol 3-Kinases; Female; Foot; Foot Deformities, Congenital; Humans; Infant; Male; Mutation; Tibial Nerve; Ultrasonography
PubMed: 33384233
DOI: 10.1016/j.bjps.2020.11.032 -
Anatomy & Cell Biology Mar 2019The medial and lateral plantar nerves are branched from the tibial nerve and move to the tip of the toes. A variation of medial plantar nerve was found on the left side...
The medial and lateral plantar nerves are branched from the tibial nerve and move to the tip of the toes. A variation of medial plantar nerve was found on the left side of a 78-year-old Korean male cadaver. The tibial nerve was divided into the lateral and medial plantar nerves beneath the plantar flexor. The medial plantar nerve passed deep to plantar aponeurosis and superficial to the flexor digitorum brevis. It gave off a common plantar digital nerve and then divided into three proper plantar digital nerves near the metatarsal bases. In this article, we report a superficial course of the medial plantar nerve and describe its unique morphology and discuss the clinical significance of this variation.
PubMed: 30984458
DOI: 10.5115/acb.2019.52.1.87 -
Insights Into Imaging Oct 2023Peripheral nerves of the lower limb may become entrapped at various points during their anatomical course. While clinical assessment and nerve conduction studies are the... (Review)
Review
Peripheral nerves of the lower limb may become entrapped at various points during their anatomical course. While clinical assessment and nerve conduction studies are the mainstay of diagnosis, there are multiple imaging options, specifically ultrasound and magnetic resonance imaging (MRI), which offer important information about the potential cause and location of nerve entrapment that can help guide management. This article overviews the anatomical course of various lower limb nerves, including the sciatic nerve, tibial nerve, medial plantar nerve, lateral plantar nerve, digital nerves, common peroneal nerve, deep peroneal nerve, superficial peroneal nerve, sural nerve, obturator nerve, lateral femoral cutaneous nerve and femoral nerve. The common locations and causes of entrapments for each of the nerves are explained. Common ultrasound and MRI findings of nerve entrapments, direct and indirect, are described, and various examples of the more commonly observed cases of lower limb nerve entrapments are provided.Critical relevance statement This article describes the common sites of lower limb nerve entrapments and their imaging features. It equips radiologists with the knowledge needed to approach the assessment of entrapment neuropathies, which are a critically important cause of pain and functional impairment.Key points• Ultrasound and MRI are commonly used to investigate nerve entrapment syndromes.• Ultrasound findings include nerve hypo-echogenicity, calibre changes and the sonographic Tinel's sign.• MRI findings include increased nerve T2 signal, muscle atrophy and denervation oedema.• Imaging can reveal causative lesions, including scarring, masses and anatomical variants.
PubMed: 37782348
DOI: 10.1186/s13244-023-01514-6 -
Diabetes Research and Clinical Practice Jun 2021Peripheral neuropathy (PN) affects two-thirds of type 2 diabetes patients (T2DM). According to diabetic PN length-dependent pattern, neurophysiological evaluation of... (Observational Study)
Observational Study
AIMS
Peripheral neuropathy (PN) affects two-thirds of type 2 diabetes patients (T2DM). According to diabetic PN length-dependent pattern, neurophysiological evaluation of foot-sole nerves might increase NCS diagnostic sensitivity, hence allowing early diagnosis of PN. Thus, we aim to assess the ability of whole plantar nerve (WPN) conduction in diabetic PN early diagnosis.
METHODS
This is a single center prospective observational cohort study on 70 T2DM patients referred to Internal Medicine Unit of A.O.U. "Luigi Vanvitelli" between October 2019/October 2020. Primary endpoint was WPN efficacy assessment in PN early detection. As secondary, we evaluated (i) a potential cut-off of SNAPs amplitude by WPN and (ii) WPN diagnostic accuracy vs. gold-standard distal sural nerve conduction.
RESULTS
ROC curve analysis allowed to establish two potential cut-offs for people aged ≤60 years (AUROC: 0.83, 95%CI: 0.69-0.96, p < 0.001) and ≤60 years (AUROC: 0.76, 95%CI: 0.59-0.93, p = 0.017). In depth, we fixed a cut-off of WPN-SNAP amplitude of 4.55 μV and 2.65 μV, respectively, with subsequent 48 patients classified as PN-T2DM.
CONCLUSIONS
Our data support WPN conduction study reliability in characterizing the most distal sensory nerve fibers at lower limbs. Thus, WPN may represent an extremely useful diagnostic tool for diabetic PN early detection.
Topics: Adult; Aged; Cohort Studies; Diabetes Mellitus, Type 2; Diabetic Neuropathies; Diagnostic Techniques, Endocrine; Early Diagnosis; Electromyography; Female; Foot; Heart Rate; Humans; Male; Middle Aged; Neural Conduction; Neurologic Examination; Peripheral Nerves; Predictive Value of Tests; Prospective Studies; Reproducibility of Results; Skin Temperature; Sural Nerve
PubMed: 33965449
DOI: 10.1016/j.diabres.2021.108856 -
Muscle & Nerve Feb 2016A new method to evaluate whole plantar nerve conduction with disposable strip electrodes (DSEs) is described.
INTRODUCTION
A new method to evaluate whole plantar nerve conduction with disposable strip electrodes (DSEs) is described.
METHODS
Whole plantar compound nerve action potentials (CNAPs) were recorded at the ankle. DSEs were attached to the sole for simultaneous stimulation of medial and lateral plantar nerves. We also conducted medial plantar nerve conduction studies using an established method and compared the findings.
RESULTS
Whole plantar CNAPs were recorded bilaterally from 32 healthy volunteers. Mean baseline to peak amplitude for CNAPs was 26.9 ± 11.8 μV, and mean maximum conduction velocity was 65.8 ± 8.3 m/s. The mean amplitude of CNAPs obtained by our method was 58.2% higher than that of CNAPs obtained by the Saeed method (26.9 μV vs. 17.0 μV; P < 0.0001).
CONCLUSIONS
The higher mean amplitude of whole plantar CNAPs obtained by our method suggests that it enables CNAPs to be obtained easily, even in elderly people.
Topics: Action Potentials; Electric Stimulation; Electrodes; Electromyography; Female; Foot; Healthy Volunteers; Humans; Male; Neural Conduction; Reaction Time; Reproducibility of Results; Statistics as Topic; Sural Nerve
PubMed: 26032401
DOI: 10.1002/mus.24715 -
Muscle & Nerve Sep 1999We report 8 cases of lateral plantar neuropathy (LPN). All had sensory impairment over the territory of the lateral plantar nerve. Near-nerve needle sensory nerve...
We report 8 cases of lateral plantar neuropathy (LPN). All had sensory impairment over the territory of the lateral plantar nerve. Near-nerve needle sensory nerve conduction study (NCS) of the plantar nerves showed abnormality confined to the lateral plantar nerve, confirming LPN. The most common cause for LPN was trauma and the most common site of injury was at the passage of the lateral plantar nerve through the abductor tunnel at the instep of the foot.
Topics: Action Potentials; Adolescent; Adult; Aged; Electrophysiology; Female; Foot; Humans; Male; Middle Aged; Nerve Compression Syndromes; Neural Conduction; Tarsal Tunnel Syndrome
PubMed: 10454719
DOI: 10.1002/(sici)1097-4598(199909)22:9<1234::aid-mus10>3.0.co;2-3