Shunt malfunction
Classification of shunt malfunction Mechanism Mechanical vs Functional Time of occurrence Early vs Late Site of malfunction Causes of malfunction Surgeon, Patient, Shunt
Oregon H S U (275 cases) Toronto- Paris (1552 cases) Denmark (884 cases) P = posterior (60 cases) A = anterior (61 cases) Chicago prospective study Shunt Survival Function DURATION C u m S u r v i v a l P A
B & W plots - Follow-up/Event DP Shunts (Toronto-Paris) - First insertion Underdrainage "Overdrainage" Improper placement Migration Fracture Obstruction XX F o l l o w - u p N =
Causes of shunt complications Early shunt complications Surgical technique Improper placement Disconnection Migration Skin problems Debris in the CSF Early Obstructions Shunt Acute overdrainage
Causes of shunt complications Late shunt complications Chronic overdrainage Hydrodynamic characteristics Mechanical stress on the device Connectors Deterioration of the distal tubing Migration & fracture Proximal obstruction
Delayed Proximal obstruction is correlated with chronic overdrainage SlitNormalEnlarged None S. Failure Ventr. Obstr
Consequences of overdrainage Rare : « slit ventricle syndrome » Epstein 1980 Very common : proximal obstruction
« Slit ventricle syndrome » Recurrent episodes of ICH despite a patent shunt Rare > 0.5% (10/3000) Loss of volumetric buffering reserve Treatment Increase the valve resistance Cranial expansion
Proximal obstruction Very frequent ICH with small ventricles at the beginning (Laplace’s law) Shunt revision
Equivalence
Hypothetically…. Prevention of late shunt malfunction by : Prevention of deterioration of the distal tubing Prevention of chronic overdrainage
Prevention of deterioration of the distal tubing Integral distal tubing - no connectors Striped distal tubing
The silent revolution Past Present
Hypothetically…. Prevention of early shunt malfunction by : ??
Answer : Series of 946 new cases of hydrocephalus in childhood ( ) 15 years of hydrocephalus treatment at Necker Thanks to Ricardo and Mercia
Series characteristics Age Median 184 day Etiologies
Type of first treatment
Third V. - results Success66.5% Factors correlated with success (Cox) Variable in the equation : ETIOLOGY Tumors 84% Meningitis20% Not in the equation : SURGEON, PATIENT’S AGE
Survival Function - Third ventriculostomy Follow-up Cum Survival
- all OSV - First shunt characteristics - all OSV - Type VP / VA667 / 1 Right / Left579 / 88 1 bilateral Tip location Correct580 Questionable 88
“questionable” placement
Shunts - results No complications % Infection % Mechanical complic %
Survival Function - valve OSV Follow-up Cum Survival % at 12 yrs = 2.5 M$ saved Probability of survival 45.9% at 15 years
Follow-up Cum Survival Survival Function - OSV vs. « DP shunts » Log Rank OSV DP shunts Dramatic decrease of late shunt complications, but number of early complications unchanged !
Prevention of early shunt complications ?
Complication types
Follow-up Cum Survival Survival Functions - Ventricular tip location (correct vs questionable) « correct » « questionable »
From the Necker collection
“Z”
“Signature”
“Almost”
“Toreador”
“Down”
“More down”
“Up”
“More up”
“The lost ventricles”
“Subway”
Conclusions Third ventriculostomy in 30% of the cases Prevention of late shunt complications have been achieved by limiting chronic overdrainage using integral, “striped” distal tubing Prevention of early shunt complications is largely up to us Good surgical technique Clean CSF Appropriate hydrodynamic characteristics of the valve