Surgical Indications and Operative Results of Lumbosubarachnoid-Lumboepidural Shunting in 29 Patients with Idiopathic Normal Pressure Hydrocephalus under Local Anesthesia

Abstract

This study consisted of 29 patients with idiopathic normal pressure hydrocephalus (iNPH) who underwent lumbosubarachnoid-lumboepidural (L-L) shunting under local anesthesia in accordance with our surgical indications of L-L shunting. (1) CSF absorption within the lumbar epidural space and shunt clearance were confirmed in all patients after operation. (2) Shunt responders (R) were 25 of 29 cases (86.2%) 3 months after surgery. Among the R, symptom exacerbation was confirmed in three patients (12%) within the follow-up period (mean, 25.1 months). In each of these patients, shunt function were maintained and remained unchanged even with pressure resetting, the cause being an intracranial/extracranial disease other than iNPH. (3) The initial pressure setting for this method was 8 cmH₂O, with gradual change to higher pressures, such that the setting for Patient 11 and thereafter became 20 cmH₂O. (4) As postsurgical complications, subcutaneous cerebral spinal fluid collection (SCC) was confirmed in five patients (17.2%). In high-pressure resetting and follow-up observation, SCC was not observed in all patients. Epidural catheter displacement was confirmed in three patients (10.3%). No recurrence was noted after the secure fixation of the catheter at the fascia insertion portion and 2 days’ postsurgical bed rest. Hence, L-L shunting is an effective shunt therapy for iNPH.