Fibular nerve neurotmesis after knee dislocation: ultrasonographic findings

Knee dislocation can cause severe fibular nerve damage, as described previously. 1,2 This traumatic event usually produces paralysis or weakness of muscles innervated by the fibular nerve (FN), with denervation and focal enlargement of the injured nerve on ultrasound (US), indicating axonotmesis. Most commonly, the FN is in continuity, and the tibial nerve (TN) is spared. 1 We present a case of traumatic knee dislocation that caused FN neurotmesis and was diagnosed by US. A 35-yearold man came to our attention after experiencing a left knee injury 2 months earlier while playing rugby. He had left foot drop. Objective evaluation revealed paralysis of tibialis anterior, fibularis longus, and extensor hallucis muscles (F50, based on the Medical Research Council scale). Electromyographic evaluation showed absence of voluntary muscle activity and prominent fibrillation potentials in the aforementioned muscles. Magnetic resonance imaging disclosed FN injury with focal enlargement in the proximal segment of the fibular bone, identified as possible amputation neuroma. Moreover, incomplete lesions of anterior cruciate and medial collateral ligaments were found. We performed US assessment of the left sciatic, fibular, and tibial nerves. The sciatic nerve (SN) appeared hypoechoic beginning in the distal third of the thigh with increased size of the fibular component, whereas the tibial division was normal (Fig. 1A). This US-detected alteration was present distally along the course of the SN and after its division into FN and TN in the popliteal fossa. At this point, the FN was hypoechoic and had an increased crosssectional area (CSA) up to 75 mm 2 (Fig. 1C). Even in the popliteal fossa, the TN was normal. In the distal portion of the popliteal fossa, the FN demonstrated further enlargement and then disappeared from view. This US finding suggested an amputation neuroma of the FN. The entire abnormal segment, involving the SN and the FN, was 150 mm in length. To check for discontinuity, we moved the probe to the level of the fibular head, where the FN was evident, and we assessed it proximally from that point. The nerve had increased CSA and was easily followed to just above the fibular head, where its orientation changed unexpectedly. Hence, we needed to rotate the probe about 908 to scan the nerve perpendicularly. The FN continued ventrally toward the patella and terminated in an amputation neuroma with a 40-mm 2 CSA (Fig. 1D). We concluded that the FN distal to the popliteal fossa was completely detached from the proximal stump (with a gap of about 60 mm) and had an abnormal L-shaped course (Fig. 1B). The patient subsequently underwent nerve grafting but had limited benefit, likely secondary to the length of the affected nerve segment (Fig. 1E and F)

Un cas d'atteinte traumatique du nerf thoracique long: données de l’échographie haute fréquence

Nous avons lu avec intérêt la publication de Nguyen et al. intitulée « Imagerie par résonance magnétique d’une scapula alata DOI de l’article original : http://dx.doi.org/10.1016/j.jbspin.2016.07.008. Ne pas utiliser, pour citation, la référence franc¸ aise de cet article, mais la référence anglaise de Joint Bone Spine avec le doi ci-dessus. dynamique secondaire à une atteinte du nerf thoracique long » . La résonance magnétique (RM) a retrouvé des signes de dénervation dans le muscle dentelé antérieur (DA) par atteinte du nerf thoracique long (TL). Selon les auteurs, l’IRM vient compléter l’examen clinique et neurophysiologique en cas d’atteinte du TL. Nous partageons totalement leur point de vue quant à l’utilité de l’imagerie dans l’évaluation des neuropathies. D’après notre expérience, l’échographie des nerfs est un outil d’exploration supplémentaire dans la prise en charge des neuropathies qui autorise également la visualisation des nerfs de petit diamètre [2]. Cette technique a très largement démontré son utilité dans l’étude des différentes atteintes nerveuses périphériques : compression, lésions traumatiques, tumeurs, neuropathies dysimmunitaires et héréditaires . L’exploration ultrasonore présente un intérêt tout particulier lorsqu’elle prolonge l’examen clinique et neurophysiologique et fournit de précieuses informations qui contribuent au pronostic, à la réadaptation et au traitement Le recours à cette méthode a vivement été recommandé dans une récente étude menée par Lieba-Samal et al. portant sur la visualisation échographique haute résolution du T

High-resolution ultrasound may depict pseudomeningocele

Pseudomeningocele is a pathological condition deriving from cerebrospinal fluid leak throughout a fissure of the dura mater. The came out fluid is enclosed in a space delimited by the soft tissues. It can be congenital, iatrogenic or traumatic (mainly in brachial plexus injury) and can be often associated with root avulsion, a severe condition which should be aware as soon as possible. The incidence of traumatic pseudomeningocele of this type is 21–57 % . In brachial plexus injury, magnetic resonance (MR) is the gold standard to assess the damage, allowing the visualization of root avulsion and pseudomeningocele . Even high-frequency ultrasound (US) may be used as first line tool in brachial plexus injury, showing data that, in some cases, require a comprehensive assessment through MR [4]. No cases of pseudomeningocele, visualized by US, have so far been reported. We describe two patients with traumatic brachial plexus injury, in whom US showed findings indicating the presence of fluid, close to a cervical root, compatible with pseudomeningocele

Extravascular heroin injection causing neuropathy: ultrasound picture

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A case of traumatic long thoracic nerve suffering: High-frequency ultrasound finding

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Ultrasound and neurophysiological correlation in common fibular nerve conduction block at fibular head

Objective Ultrasound (US) and neurophysiological examination are useful tools in the evaluation of common fibular mononeuropathy. There is only a report comparing US and electrophysiological parameters in patients with common fibular nerve (CFN) conduction block at fibular head. We investigated the correlation between US and neurophysiologic findings in this condition. Methods We retrospectively reviewed patients with CFN assessed in our lab during last 2 years. Each patient underwent to clinical, neurophysiological and ultrasound evaluations. Cross sectional area (CSA) of CFN at fibular head was assessed. Results Twenty-four patients were included. Motor nerve conduction study showed a reduction of distal compound muscle action potential (CMAP) amplitude in 10 patients (mean 1.3 mV). US showed an increased CSA in 10 patients. Statistical analysis revealed a strong correlation between the increased CSA and the CMAP reduction of CFN. Conclusion Our data suggest that usually US examination is normal in CFN conduction block at fibular head. However the association with axonal damage is frequently accompanied by an increase of CSA. Significance Ultrasound evaluation may represent a powerful diagnostic/prognostic tool in cases with CPN conduction block at fibular head because it usually shows normal pattern in pure conduction block and increase of CSA in associated axonal damage

Bilateral tarsal tunnel syndrome related to intense cycling activity: proposal of a multimodal diagnostic approach

Tarsal tunnel syndrome (TTS) is an entrapment neuropathy of the posterior tibial nerve or its branches (medial plantar, lateral plantar and calcaneal nerves) within its fibro-osseous tunnel beneath the flexor retinaculum on the medial side of the ankle. TTS is a rare and likely underdiagnosed condition due to extrinsic (e.g. space occupying lesions, traumas) or intrinsic causes. Symptoms depend on the involved branch, but usually patients complain of burning, tingling and pain along the foot plantar region, sometimes radiated to the distal part of the medial region of the leg. Symptoms often worsen walking or after prolonged standing or using high-heeled shoes. TTS diagnosis is often difficult and no gold standard test is available. A recent review of the literature highlights the lack of high-quality evidence-based data and the still controversial role of nerve conduction studies, where false-positive and false-negative data are frequent [1]. Neurophysiology and neuroimaging may provide useful information but rarely diagnostic certainty. The combination of neurophysiology and nerve ultrasound (US) has been shown to improve diagnosis and therapeutic approach in other entrapment neuropathies and a recent paper presents the results of ultrasound examination in 81 patients with TTS. There are no reference values in US diagnosis of TTS because of the high variability of compression sites

Intermittent ulnar nerve compression due to accessory abductor digiti minimi muscle: Crucial diagnostic role of nerve ultrasound

Nerve entrapment is a common pathologic condition with a diagnosis that relies on clinical and neurophysiologic evaluations. Nerve entrapment can be caused by anatomic variations, such as accessory muscles. In the past, the diagnosis could only be made during surgical exploration, but recently ultrasonography (US) has allowed us to find atypical structures surrounding and compressing nerves. Among muscle variations, the accessory abductor digiti minimi (AADM) is the most common aberrant muscle in the Guyon canal, with an incidence of 22.4%

US diagnosis of sciatic nerve tumor proximal to gluteal fold

High-resolution ultrasound (US) is a helpful technique for the evaluation of peripheral nerves. It is now well accepted that especially in nerve mononeuropaties the combination of morphological data, obtained through US, and functional data, obtained through electrophysiology, is the appropriate way to reach the best diagnosis including information for therapeutical decision. Literature data show that US may crucially influence diagnosis and clinical care in nerve tumors [1, 2]. However, nerve US has some limitations. In particular the visualization of deep nerves is difficult, especially in overweight people. This is the case of proximal part of sciatic nerve that is commonly detectable only distal to the gluteal fold. We report on a 48-year-old woman complaining of pain and electric shocks radiated to sciatic course and trigger point in the right gluteal region. Clinical examination showed only mild right extensor hallucis longus weakness. Needle electromyography of tibialis anterior, gastrocnemius, peroneus longus was normal and mild chronic neurogenic recruitment was observed in extensor hallucis longus. It was suspected a right L5 radiculopathy but magnetic resonance (MR) showed only a mild L5–S1 bulging that was not considered the cause of symptoms. US of sciatic nerve was then performed although the trigger point was in a region where usually sciatic nerve is not detectable, proximally to the gluteal fold. US was performed using a linear 6–10 and 10–18 MHz transducer and sciatic nerve was bilaterally evaluated in distal–proximal direction starting from the popliteal fossa. Right sciatic nerve was detectable along all its course, even proximally to the gluteal fold although with no optimal visualization. At the middle-third of the gluteus a fusiform hypoechoic increase of nerve volume was found. The maximum longitudinal diameter was 2.5 cm and maximum antero-posterior diameter was 2.0 cm (max cross-sectional area 4.5 cm2). An accurate evaluation of the US video clip suggested that the mass raised from lateral fascicles sparing and dislocating remaining medial fascicles (Fig. 1a, b). US and clinical data suggested a sciatic nerve tumor, likely a schwannoma. MR confirmed the lesion showing a partially preserved fascicular structure, suggesting a schwannoma (Fig. 1c–f). Surgical excision was refused by the patient and US monitoring planned. Our case report confirms the usefulness of US in the diagnosis of nerve tumors. US is not able to clearly differentiate the type of nerve tumor but can provide useful information to discriminate between the two main types, schwannoma or neurofibroma [3–5]. Schwannoma typically displaces the nerve fascicles and generally is positioned eccentrically to the affected nerve segment. Another typical feature especially of large lesions is the presence of hyperechoic calcifications and internal degenerative cystic foci. On the other side neurofibroma presents as a concentric lesion that does not displace the fascicular elements of the nerve but interferes with them (usually fascicles are not detectable). Another typical sonographic feature of this kind of tumor is the so-called ‘‘target sign’’ (layered aspect, with a hyperechoic centre and a peripheral hypoechoic rim, best seen on transverse scans) [6]. Usually sciatic nerve is not detectable with US proximally to gluteal fold but in our case the visualization of proximal part of the nerve was possible because the patient was athletic, skinny and the tumor was big. In general our case suggests to perform US also in district where usually for anatomical reasons nerves are not clearly or totally viewable, because sometimes macroscopic nerve enlargement may be detected