No abstract

Cranial nerve involvement in Charcot-Marie-Tooth disease (CMT) is rare, though there are a number of CMT syndromes in which vocal cord paralysis is a characteristic feature. CMT disease due to mutations in the ganglioside-induced differentiation-associated protein 1 gene (GDAP1) has been reported to be associated with vocal cord and diaphragmatic palsy. In order to address the prevalence of these complications in patients with GDAP1 mutations we evaluated vocal cord and respiratory function in nine patients from eight unrelated families with this disorder. Hoarseness of the voice and inability to speak loudly were reported by eight patients and one had associated symptoms of respiratory insufficiency. Patients were investigated by means of peripheral and phrenic nerve conduction studies, flexible laryngoscopy, pulmonary function studies and polysomnography. Nerve conduction velocities and pathological studies were compatible with axonal CMT (CMT2). Flexible laryngoscopy showed left vocal cord palsy in four cases, bilateral cord palsies in four cases and was normal in one case. Restrictive respiratory dysfunction was seen in the eight patients with vocal cord paresis who were all chair-bound. These eight had confirmed phrenic nerve dysfunction on neurophysiology evaluation. The patient with normal vocal cord and pulmonary function had a less severe clinical course.This study shows that CMT patients with GDAP1 mutations develop severe disability due to weakness of limb muscles and that laryngeal and respiratory muscle involvement occurs late in the disease process when significant proximal upper limb weakness has developed. The early and predominant involvement of the left vocal cord innervated by the longer left recurrent laryngeal nerve suggests a length dependent pattern of nerve degeneration. In GDAP1 neuropathy, respiratory function should be thoroughly investigated because life expectancy can be compromised due to respiratory failure.

Objectives: Imaging assessment for the clinical management of femoroacetabular impingement syndrome (FAIS) remains controversial because of a paucity of evidencebased guidance and notable variability in clinical practice, ultimately requiring expert consensus. The purpose of this agreement is to establish expert-based statements on FAIS imaging, using formal techniques of consensus building driven by relevant literature review. Methods:The validated Delphi method and peer-reviewed literature were used to formally derive consensus among 30 panel members (21 musculoskeletal radiologists and 9 orthopedic surgeons) from 13 countries.Forty-two questions were agreed on, and recent relevant seminal literature was circulated and classified in five major topics ("General issues", "Parameters and reporting", "Radiographic assessment", "MRI evaluation" and "Ultrasound") in order to produce answering statements.The level of evidence was noted for all produced statements and panel members were asked to score their level of agreement with each statement (0 to 10) during iterative rounds. Either "group consensus", "group agreement" or "no agreement" was achieved.Items near consensus were further queried using 4 moderated group sessions and in 4 Delphi rounds.Results: Forty-five statements were generated and group consensus was reached for 43 (95.7%). Seventeen of these statements were selected as most important for dissemination in advance. There was no agreement for the two statements pertaining to "Ultrasound". Conclusion:The first international Delphi-based consensus for the imaging assessment of FAIS was developed. The resulting consensus can serve as a tool to reduce variability in clinical practices and guide further research for the clinical management of FAIS. Key Points• FAI imaging literature is extensive although often of low level of evidence.• Radiographic evaluation with a reproducible technique is the cornerstone of hip imaging assessment.• MRI with a dedicated protocol is the gold standard imaging technique for FAI assessment.