Relationship Between Idiopathic Normal-Pressure Hydrocephalus and Lumbar Spinal Stenosis

<jats:title>Abstract</jats:title> <jats:p><jats:bold>Object</jats:bold>: To evaluate the relationship between idiopathic normal-pressure hydrocephalus (iNPH) and lumbar spinal stenosis (LSS).<jats:bold>Methods</jats:bold>: With the aging of society, the numbers of patients with iNPH and LSS are likely to increase. iNPH and LSS have similar symptoms including gait disturbance and urinary dysfunction. The prevalence of dementia is higher in older adults with LSS. However, the relationship of LSS with iNPH and the prevalence of LSS in patients with iNPH are unknown. In our department between April 2011 and March 2017, 226 patients were diagnosed with iNPH and underwent shunt operation including lumboperitoneal shunts and ventriculoperitoneal shunts. Two spine surgeons evaluated LSS on magnetic resonance imaging of the lumbar spine. Age, sex, body mass index, Timed Up and Go test, Mini Mental State Examination score, and urinary dysfunction were examined before and after surgery for iNPH. Changes in these variables were compared between patients with iNPH without LSS and with iNPH and LSS.<jats:bold>Results</jats:bold>: In the overall cohort, the median patient age was 78 years and there were 121 males. Among 226 patients with iNPH, 73 (32.3%) had LSS. Neurological symptoms were improved in all patients at final follow-up. The rate of symptom improvement was lower for the iNPH and LSS group compared with the iNPH without LSS group.<jats:bold>Conclusions</jats:bold>: Surgery to improve gait disturbance might be difficult in patients with iNPH with LSS. When examining patients with iNPH, we should consider the possibility of concomitant LSS.</jats:p>