Lumbosubarachnoid-lumboepidural shunting in patients with idiopathic normal-pressure hydrocephalus: surgical procedures and follow-up study of five cases

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

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.

Long-term 4 Years Follow-up Study of 482 Patients Who Underwent Shunting for Idiopathic Normal Pressure Hydrocephalus -Course of Symptoms and Shunt Efficacy Rates Compared by Age Group

A total of 482 operated idiopathic normal pressure hydrocephalus (iNPH) patients were divided into those aged <80 years at the time of surgery (group A: 400 cases; and male-to-female ratio, 259:141) and ≥80 years (group B: 82 cases; male-to-female ratio, 43:39) and comparatively investigated based on the following variables: (1) temporal changes in shunt efficacy rates, and (2) temporal changes in each symptom, including the patient’s fall frequency and preoperative modified Rankin Scale (mRS) score and during follow-up at 3, 6 months, 1–4 years postoperatively. (1) The shunt efficacy rates at 3 months and 4 years postoperatively were 93% and 82%, respectively, in group A and 92.3% and 70.7%, respectively, in group B. This demonstrates a decrease in shunt efficacy at 4 years postoperatively, regardless of the persistence of shunt function or adjustments in setting pressure. This trend was particularly observed in group B. In group A, 41 (9.8%) cases had decreased efficacy rate, compared with 21 (25.6%) cases in group B, which occurred due to complications with an extracranial or intracranial disease. (2) Gait disturbance (G) and urinary incontinence (U) showed signs of improvement in the early postoperative stage, while dementia (D) and mRS score began to gradually improve from 6 months postoperatively. Patient’s fall frequency tended to become higher until 6 months postoperatively than the preoperative rate. In group A, symptom improvement was comparatively maintained until 4 years postoperatively, while in group B, all symptoms and mRS tended to gradually deteriorate beginning at 3 years postoperatively.

Shunt Devices for the Treatment of Adult Hydrocephalus: Recent Progress and Characteristics

Various types of shunt valves have been developed during the past 50 years, most of which can be classified into the following categories: (1) fixed differential pressure valves; (2) fixed differential pressure (DP) valves with an antisiphon mechanism; (3) programmable DP valves; (4) programmable DP valves with an antisiphon mechanism; and (5) programmable antisiphon valves. When considering the myriad of possible postoperative condition changes, such as the onset of accidental non-related diseases or trauma in adults, and changes in normal physiological development or anticipation of future shunt removal in children, it has become standard to use the programmable valve as a first choice for cerebrospinal fluid shunting. However, it is still unclear what type of shunt valve is suitable for each individual case. Based on the results of SINPHONI and more recently SINPHONI 2 trials, the programmable DP valve is recommended as the first line shunt valve. The programmable DP valve with an antisiphon mechanism is thought to be beneficial for tall, slender patients, who have a tendency for easily developing complications of overdrainage, however, this type of valve must be used cautiously in obese patients because of the increased risk of underdrainage. Although the current evidence is still insufficient, the programmable antisiphon valve, which costs the same as the programmable DP valve, is also thought to be the first line shunt valve. The quick reference table is applicable for most shunt valves, and for patients with either the ventriculoperitoneal or the lumboperitoneal shunt.