Shunt malfunctionShunt malfunctionShunt malfunctionShunt 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

6 5 4 3210

Cum Survival

1.0

.9

.8

.7

.6

.5

.4

P

A

B & W plots - Follow-up/Event

DP Shunts (Toronto-Paris) - First insertion

Underdrainage

"Overdrainage"

Improper placement

Migration

Fracture

Obstruction XX

Follow-up

211568284288334N =

2800

2400

2000

1600

1200

800

400

0

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 tubingMigration & fracture

Proximal obstruction

Delayed Proximal obstruction is Delayed Proximal obstruction is correlated with chronic overdrainagecorrelated with chronic overdrainage

Slit Normal Enlarged

None 55.7 78.3 63.9

S. Failure 44.344.3 21.7 36.1

Ventr. Obstr. 81.381.3 8.1 21.4

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 (1987-2002)

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

Success 66.5%

Factors correlated with success (Cox)

Variable in the equation : ETIOLOGY

• Tumors 84%

• Meningitis 20%

Not in the equation : SURGEON,

PATIENT’S AGE

Survival Function - Third ventriculostomy

Follow-up

3600

3240

2880

2520

2160

1800

1440

1080

720

360

0

Cum

Sur

viva

l1.0

.9

.8

.7

.6

.5

.4

.3

.2

.10.0

First shunt characteristics - all OSV -- all OSV -

Type

VP / VA 667 / 1

Right / Left 579 / 88 1 bilateral

Tip location

Correct 580

Questionable 88

“questionable” placement

Shunts - results

No complications 411 61.5%

Infection 49 7.3%

Mechanical complic. 208 31.1%

Survival Function - valve OSV

Follow-up

5400

5040

4680

4320

3960

3600

3240

2880

2520

2160

1800

1440

1080

720

360

0

Cum

Sur

viva

l

1.0

.9

.8

.7

.6

.5

.4

.3

.2

.1

0.0

50% at 12 yrs

=

2.5 M$ saved

Probability of survival 45.9% at 15 years

Follow-up

Cum

Sur

viva

l

4320

3960

3600

3240

2880

2520

2160

1800

1440

1080

720

360

0

1.0

.9

.8

.7

.6

.5

.4

.3

.2

.1

0.0

Survival Function - OSV vs. « DP shunts »

Log Rank 0.000

OSV

DP shunts

Dramatic decrease of late shunt complications,Dramatic decrease of late shunt complications,but number of early complications unchanged !but number of early complications unchanged !

Prevention of early shunt complications ?

Complication types

Follow-up

5400

5040

4680

4320

3960

3600

3240

2880

2520

2160

1800

1440

1080

720

360

0

Cum

Sur

viva

l1.0

.8

.6

.4

.2

0.0

Survival Functions - Ventricular tip location (correct vs questionable)

« correct »

« questionable »

From the Necker collectionFrom 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