[Scintigraphic imaging in the diagnosis of failed intrathecal baclofen therapy: a case report of a 7-year-old boy with ventriculoperitoneal shunt].

Intrathecal baclofen (ITB) therapy is popular for the management of intractable spasticity. In 2007, the indications of ITB therapy expanded to include spasticity of children in Japan. In this report, we assessed the utility of radioisotopic scintigraphy in the diagnosis of failed ITB therapy. A 7-year-old boy with schizencephaly, hydrocephalus, and spastic quadriplegia had an ITB pump implanted. In his infancy, he had undergone ventriculoperitoneal shunt implantation. One month after the ITB operation, the ITB therapeutic effect diminished. Several examinations confirmed that the pump function was normal and catheter failure had not occurred. However, radioisotopic scintigraphy revealed that the baclofen had been washed out to blood circulation more rapidly than is typically observed. We considered two possible causes for this; obstruction of the cerebrospinal space due to kyphosis and excessive washout of celebrospinal fluid through the ventriculoperitoneal shunt. The catheter was moved to a more caudal site surgically, and his spasticity improved. The use of radioisotopic scintigraphy to identify the distribution of baclofen is an effective technique for investigation of baclofen pump system malfunction.