A Study of the Indian Valve for Ventriculo-atrial Shunts in the Treatment of Hydrocephalus

GURMAIL SINGH MICHAEL ANTHONY LlJIS LEON hifAR/NO ROBERT B. ZACHARY

Introduction Up to a few years ago the treatment of hydrocephalus in India was rarely undertaken

because the country could not afford to import costly shunts from abroad. In 1969, Dr. Upadhyaya at the All-India lnstitute of Medical Sciences, New Delhi, designed and developed a shunt made entirely of 'Silastic'. The main characteristics of this shunt and of the three others commonly used are shown in Figure I . It consists of a ventricular catheter, a flushing device and a cardiac catheter. The flushing chamber is 4cm in length and about 0.5cni in diameter. I t houses a proximal trap-door valve on the inlet catheter. Near the lower end of tlie cardiac catheter is the distal valve, in the form of two vertical slits 0.7cm in length and placed at an angle of 180 to each other. Structurally, it most closely resembles thc Denver shunt.

The original shunt was hand-made. The valve was not radio-opaque and was available i n one pressure range only. Sterilisation by Liutoclaving was recommended.

We have tested the hydrodynamics of five of the original, hand-made, shunts and five of

METHOD I N D I A N PUDENZ D f N V E R HOLTER

L 4 0 0 M M n N O R M A L S A L I N E R O O M T E M P VALVE F ILLED WITH F L U I D

(Lest) Fig. 1. Diagrams of Indlan valve and oiher val\e\ in common use. ( A bo tie) Fig. 2. Apparatus to te\t hydrodynamic propertie\.

Department of Paediatric Surgery and Regional Medical Physics Department. The Children's Hospital Sheffield S10 3BR.

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DEVELOPMENTAL MEDICINE AND CHILD NEUROLOGY. 1975, 17. Supp. 35

the later version which is now manufactured commercially (Indian Surgical Instruments, Bombay).

Method The hydrodynamics of a shunt system can be determined experimentally by barious

methods. Rayport and Reiss (1969) and Hakim er al. (1973) evaluated the various shunts in a pulsatile situation, while Fox et al. (1972) employed a non-pulsatile system. However, it is difficult to say how far these bench tests simulate or correlate with the actual hydro- dynamics of cerebrospinal fluid in a hydrocephalic child.

We have used a simple, non-pulsatile, system designed by the Regional Medical Physics Department in Sheffield (Fig. 2). A container filled with fluid is connected by a tube to the valve system to be tested. Hydrostatic pressure is given by the difference in height between the top level of the fluid in the container and the lowest point in the valve system. The experiment was carried out at a constant pressure-head, ranging from 0 to 400mm saline, at room temperature. The fluid was collected over a period of five minutes and then meacured in a calibrated burette. The rate per minute (flow rate) was then calculated.

Results Original Slr un t

Our earlier study of the five hand-made shunts revealed seberal features which wsmed undesirable. ( 1 ) At a pressure of lOOmm water, the flow rates varied between 0.07 and 0.4ml/min. with a mean of 0.2ml/min-a figure which we considered rather low. Flow rates at higher pressures appeared to be satisfactory. (2) After sterilisation by autoclaving the flow rates increased on the whole, but the tKect of autoclaving was unpredictable. (3) The flap-valve in the flushing chamber was not completely competent. It allowed retro- grade flow at pressures of 200mm water, and even at 700mm water. (4) Pumping the chamber produced a backward as well as a forward flou ( 5 ) The ’spillover’ pressure (the lowest pressure at which there is detectable flow through the valve) varied between 40 and 60mm water. an acceptable figure. However, onl) one pressure range of valves was being produced.

Newer C‘ersion In the manufactured versions of the Upadhyaya shunt the flou through the valve 111 the

flushing chamber was slower at pressures from 400mm to lOOmm than was the flow through the lower catheter (Fig. 3). A comparison of the medium-pressure Upadhyaya. Holter, Pudenz and Denver shunts (Fig. 4) shows a good linear relationship between pressure and flow rates, with a flow rate of more than 0.3ml/min in the Upadhyaya valve at a pressure of 100nil water. The ‘spillover’ pressure of the new valves is comparable with those of the other shunts, and they are available in three pressure ranges.

Comments The commercially-produced Upadhyaya valve for ventriculo-atrial shunts compares

favourably with other valves with respect to hydrodynamic properties. the proximal flap- valve is now competent and flow through the system is in one direction only. The shunt

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H O L T E H

U P A O H Y A Y A ? , D t N V t R U P A O H Y A Y l l P U O f N Z / 4 0 0 , .. . . ,/'

I r

( Ahovr) Fig. 3. ConiDartson of resistance of valve. flushiiw chiniber and lower catheter of Indian valve.

300 ..

( R i g h t ) Fig. 4. Cornparibon of pres\ures and flou -rate\ in Indian and other valve\

FLOW R A T E < M L S / m i n )

is of simple construction. composed entirely of 'silastic': it lies well under the scalp and is unlikely to cause ulceration.

The valve is sterilised by gamma rays, and i t is possible that its simple construction will discourage colonisation. The lower end of the system is now radio-opaque so that its position in the heart can be checked at operation and in the follow-up period.

The Upadhyaya valve appears to be as good as the other valves currently in use. I t has the additional advantage that it can be produced for a modest price of 125 Rupees (about f6.67), compared with about f45.00 for the other commercially-available valves.

Up to the present, 3000 Upadhyaya valves (including the original ones made by hand in Dr. Upadhyaya's department) have been used at medical centres in India. and over 250 have been used i n the Department of Paediatric Surgery in the All-India Institute of Medical Sciences in New Delhi.

SkIM MARY

Because of the high costs of importing commercially-available shunts, a hand-made \cntriculo-atrial shunt was devised in India for the treatment of hydrocephalus. Modifica- tions have been made to the original design and these shunts are now being produced commercially at a fraction of the cost of other available shunts. Hydrodynamic testing indicates that they compare favourably with the other shunts at present in use.

R G S U M E .VOII~YWLI .sIiiuii ~.c.ritr.ic.rrlr)-~lrial d'originc. indienne pour le fvaifeiiietit c/e l ' i i~ydvoc@Mie En raison dir coGt elevC des shunts iniportes disponibles dans le commerce, un shunt

\cntriculo-atrial fait main a ete rtalise en Inde pour le traitement de I'hydrociphalie. Des tnodifications ont kte apportees au dessin original et ces shunts sont maintenant produits

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DEVELOPMENTAL MEDICINE AND CHILD NEUROLOGY. 1975, 17. supp. 35

commercialement pour une fraction du coOt des autres shunts disponibles. Les epreuves hydrodynamiques suggerent une comparaison favorable avec d’autres shunts utilists jusqu’h ce jour.

ZUSAMMENFASSUNG

Eiti neuer Indischer ventrikulo-atrialer Shunt zur Therapie des Hydrocephalus Wegen der hohen Importkosten der im Handel erhaltlichen Shunt-Systeme wurde ein

handgefertigter ventrikulo-atrialer Shunt in Indien eingefuhrt zur Behandlung des Hydro- cephalus. Moditikationen der originalen Ausfuhrung wurden durchgefuhrt, und diese Ventilkonstruktionen werden jetzt kommerziell produziert mit einem Bruchteil der Kosten der anderen verfugbaren Shunt-Systeme. Hydrodynamische Untersuchungen lassen vermuten dab sie den Vergleich mit anderen zur Zeit in Gebrauch befindlichen Shunt-Systemen gut bestehen.

RESUMEN

Utio nuevu derivacion ventriculo-atrial india, en el tratamiento de in hidrocefalicl Debido al alto precio de las derivaciones comerciales importadas asequibles, en la India

se ha realizado una derivaci6n ventriculo-atrial, hecha a mano, para el tratamiento de la hidrocefalia. Se modific6 el esquema original y actualmente estas derivaciones se producen comercialniente por una fracci6n del costo de otras derivaciones asequibles. Los tests hidrodindmicos sugieren que puedeii compararse favorablemente con otras derivaciones actualmente en uso.

REFERENCES Hakim, S., Duran de la Roche, F., Burton, J. D. (1973) ‘A critical analysis of valve shunts used in the treat-

Fox, J. L., McCullough, D. C., Green, R. C. (1972) ‘Cerebrospinal fluid shunts: an experimental comparison

Rayport, M., Reiss. J. L. (1969) ‘Hydrodynamic properties of certain shunt assemblies for the treatment of

ment of hydrocephalus.’ Developmental Medicine and Child Neurology, 15, 230.

of flow rates and pressure values in various commercial shunts.’ Journal of Neurowrgery, 37,700.

hydrocephalus.’ Journal of Neurowrgery, 30, 455.

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