Daniele Coraci

Carpal tunnel syndrome: clinical features, diagnosis, and management

Carpal tunnel syndrome is the most common peripheral nerve entrapment syndrome worldwide. The clinical symptoms and physical examination findings in patients with this syndrome are recognised widely and various treatments exist, including non-surgical and surgical options. Despite these advantages, there is a paucity of evidence about the best approaches for assessment of carpal tunnel syndrome and to guide treatment decisions. More objective methods for assessment, including electrodiagnostic testing and nerve imaging, provide additional information about the extent of axonal involvement and structural change, but their exact benefit to patients is unknown. Although the best means of integrating clinical, functional, and anatomical information for selecting treatment choices has not yet been identified, patients can be diagnosed quickly and respond well to treatment. The high prevalence of carpal tunnel syndrome, its effects on quality of life, and the cost that disease burden generates to health systems make it important to identify the research priorities that will be resolved in clinical trials.

Nerve ultrasound findings in neuropathy associated with anti-myelin-associated glycoprotein antibodies

No systematic nerve ultrasound (US) studies on patients with neuropathy and anti‐myelin‐associated glycoprotein (anti‐MAG) antibodies are available.

Fibular nerve damage in knee dislocation: spectrum of ultrasound patterns.

At least 25% of knee dislocations are associated with common fibular nerve injury. Diagnosis is usually based on clinical and neurophysiological findings. We assessed the role of nerve ultrasound in common fibular nerve injury.

Ultrasound assessment of sural nerve in Charcot–Marie-Tooth 1A neuropathy

OBJECTIVE Nerve ultrasound (US) has been used to study peripheral nerve disease, and increase of the cross-sectional area (CSA) has been described in demyelinating polyneuropathy. The objective of the current study is to characterise the US features of the sural nerve in a sample of Charcot-Marie-Tooth (CMT) 1A patients. METHODS A total of 20 CMT1A patients were enrolled. As control group we studied 37 age- and sex-matched subjects. All patients underwent clinical examination, neurophysiology and US evaluation of the bilateral sural nerve and right ulnar nerve. US results were correlated with neurophysiology and clinical data. RESULTS Sural nerve CSA was not increased in the majority of patients (70%), whereas an increased ulnar nerve CSA was present in the whole sample. Inverse relations were found between CSA of the ulnar nerve and body mass index (BMI) (p<0.0002, R=-0.8) and CSA of the sural nerve and age (right 0.006, R=-0.6, left 0.002, R=-0.6 and left and right p=0.00003, R=-0.4). CONCLUSIONS US showed ulnar CSA enlargement and normal sural nerve CSA. SIGNIFICANCE The significance of normal sural nerve CSA in CMT1A patients need to be further investigated, possibly through longitudinal studies.

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.

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%. The AADM has been reported to entrap the ulnar nerve at the wrist. We present a case of US diagnosis of ulnar nerve compressed by an AADM. A 24-year-old, right-handed man came to our attention for a 6-year history of right handgrip weakness after repetitive manual activity (especially wrist extension). In the last year right wrist pain also occurred. Clinical examination revealed no weakness or atrophy in the hand muscles. No sensory deficits were detected, although the patient complained of paresthesia of the medial 3 fingers. Sensory and motor conduction velocity and amplitude of the radial, median, and ulnar nerves bilaterally were normal, revealing no axonal/demyelinating damage. Needle electrmyography was not performed. US evaluation of the right ulnar nerve from the wrist to the axilla showed no alterations in nerve dimension or echogenicity. In the ventral portion of the distal third of the forearm, we found an atypical muscular structure that ran over the ulnar nerve and the Guyon canal, reaching the abductor digiti minimi muscle. The muscle seemed to pass over the Guyon canal ligament and near the ulnar artery (Fig. 1A and B). This accessory muscle was innervated by accessory branches from the right ulnar nerve (Fig. 1C). Evaluation of the left hand revealed a similar structure. The position and electrophysiologic features of the accessory muscle suggested it was an AADM. Dynamic US showed an increased anteroposterior diameter of the muscle during handgrip, which produced compression on the underlying ulnar nerve. Magnetic resonance imaging of the hands confirmed the presence of the AADM. The patient underwent surgical intervention. The surgeon followed the drawing we had made on the skin based on the US examination and confirmed the presence of a 7-cm-long muscular structure (Fig. 1D), which was removed. Two weeks after surgery the patient reported symptom improvement. US in this case provided crucial anatomic evidence of an accessory muscle that otherwise would not have been diagnosed. We hypothesize that the intermittent symptoms were related to transient neuroapraxic block after hand stress. Moreover, handedness and anatomic features probably caused more nerve stress on the right side than on the left. It is likely that the normal neurophysiologic and clinical picture and transient symptoms would have led the patient to not have surgical treatment. By identifying the actual cause of symptoms, US allowed us to proceed with a tailored therapeutic approach. Surgical exploration confirmed the US findings and decompressed the nerve. Knowledge of anatomic variation is essential for the surgeon to perform the best intervention for the patient.

Ultrasound diagnosis of peroneal nerve variant in a child with compressive mononeuropathy

We report on a 6-year-old child presenting with subacute foot drop. Neurophysiologic and radiologic studies revealed a peroneal nerve compression secondary to fibular exostosis. Before undergoing surgical removal of the exostosis, the patient underwent further neurophysiologic and ultrasonographic evaluation that showed the presence of an accessory peroneal nerve branch that caused gastrocnemius involvement. Findings at surgery confirmed the supposed anatomical variant. Both nerve components were carefully preserved during the operative procedure. The association of ultrasonographic and neurophysiologic studies was crucial in identifying the etiopathologic mechanism and anatomical picture and provided clinicians and surgeons with important information in planning the procedure.

Ultrasound evaluation in transthyretin-related amyloid neuropathy

Introduction: Familial amyloid polyneuropathy is a rare condition caused by mutations of the transthyretin gene (TTR). We assessed the pattern of nerve ultrasound (US) abnormalities in patients with TTR‐related neuropathy. Methods: Seven patients with TTR‐related neuropathy (TTR‐N) and 5 asymptomatic TTR‐mutation carriers (TTR‐C) underwent neurological examination, nerve conduction studies, and US evaluation. Results: Multifocal US abnormalities were identified in 6 of 7 TTR‐N patients. A single patient with only a mild sensory polyneuropathy had normal nerves on US evaluation. In the TTR‐C, we only detected an enlarged ulnar nerve at the elbow. Interestingly, disease severity correlated with number of nerves affected on US evaluation. Conclusions: No specific pattern of US abnormalities was identified in this cohort. However, in TTR‐related amyloid neuropathy, US may be a helpful tool in monitoring disease progression, and/or clinical response to pharmacological treatment. Muscle Nerve 50: 372–376, 2014

Secondary posterior interosseous nerve lesions associated with humeral fractures

Radial nerve lesions associated with humeral shaft fractures are the most common traumatic nerve lesions observed with long bone fractures. Secondary indirect posterior interosseous nerve (PIN) lesions can be associated with traumatic radial nerve palsy. The aim of this study was to identify cases of traumatic double‐site radial nerve involvement through ultrasound (US).

Thoracic outlet syndrome: wide literature for few cases. Status of the art

Despite its low prevalence and incidence, considerable debate exists in the literature on thoracic outlet syndrome (TOS). From literature analysis on nerve entrapments, we realized that TOS is the second most commonly published entrapment syndrome in the literature (after carpal tunnel syndrome) and that it is even more reported than ulnar neuropathy at elbow, which, instead, is very frequent. Despite the large amount of articles, there is still controversy regarding its classification, clinical picture, diagnostic objective findings, diagnostic modalities, therapeutical strategies and outcomes. While some experts believe that TOS is underrated, overlooked and very frequent, others even doubt its existence as a nosological entity. In the attempt to shed more light on this condition, we performed a systematic review of the literature and report evidence and opinions around this controversial subject. Only articles focused on neurogenic TOS were considered. Understanding the status of the art and the underlying reasons of doubts and weaknesses could help clinical practice and set the stage for future research.