[Lumbo-Peritoneal Shunt for Patients with Idiopathic Normal Pressure Hydrocephalus:Surgical Technique]

The SINPHONI-2 study(a group of Japanese prospective multicenter cohort studies on the treatment of idiopathic normal pressure hydrocephalus[iNPH])showed the safety and efficacy of lumboperitoneal(L-P)shunt surgery for iNPH. A total of 660 probable iNPH patients underwent L-P shunt surgery at our NPH center between April 2009 and March 2020(age: 77.3 ± 6.2 years). Our surgical technique includes 1)general anesthesia, 2)use of the original drape, 3)upward insertion of the spinal tube through L2/3 via a paramedian puncture in patients with highly deformed lumbar spines, 4)posterior placement of a Codman Hakim programmable valve with Siphonguard^TM, 5)inclination of the table at a 35° angle without position change and re-sterilization, 6)laparotomy via rectal muscle splitting, and 7)oblique maneuvering the peritoneal tube from the upper lateral to the lower medial sector. During the first year after surgery, postoperative complications occurred in 14 of 172 patients (8.1%), including four patients with chronic subdural hematoma requiring evacuation (2.3%), three with spinal tube occlusion (1.7%), three with migration of the spinal tube, two with lower-limb numbness (1.2%), and two with abdominal tube occlusion. Our L-P shunt procedure seems to be generally acceptable considering the low number of complications.