Double Crush Syndrome of the Median Nerve: A Literature Review

Abstract

Double crush syndrome (DCS) is defined as the compressive involvement of the same peripheral nerve in different segments. When this syndrome affects the median nerve, a proximal compression of a spinal nerve that will constitute this structure (often the spinal nerve at the C6 vertebra) is usually noted at the cervical spine level as a herniated disc and as a distal compression at the level of the carpal tunnel. Epidemiological data on median nerve compromise by DCS are still very scarce in the medical literature. The diagnosis can be inferred by symptoms and signs occurring proximally and distally in the arm, as well as by alterations revealed by upper limb electromyography and neuroimaging studies, such as magnetic resonance imaging (MRI) of the cervical spine. Nowadays, information on which compressed neuroanatomical point should be initially addressed still depends on further studies. Limited data infer that these patients, when submitted to surgical treatment in only one of the median nerve compression points, evolve with worse functional outcomes than the surgically-treated group with carpal tunnel syndrome without DCS. ResumoA síndrome do duplo impacto (SDI) é conceituada como o comprometimento compressivo de um mesmo nervo periférico em segmentos distintos. Quando esta síndrome acomete o nervo mediano, usualmente se nota uma compressão proximal de um nervo espinhal que irá constituir o nervo mediano (frequentemente, o nervo espinhal da vértebra C6) ao nível da coluna cervical por uma hérnia discal e uma compressão distal ao nível do túnel do carpo. Dados epidemiológicos sobre a SDI comprometendo o nervo mediano ainda são muito escassos na literatura médica.