Technical

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Spinal

Needle

with

Notes

Depth Guide: Subarachnoid

A New Design Injections

VINCENT In performing now

of

a routine

lumbar

select the advanced space

best level through

between feel

operator

palpates

the

to

identify

midline

and

spinous

canal,With

pop”

“

the

for puncture. The spinal overlying soft tissues,

spinal a

tap,

processes

adjacent

the osseous may

spinal

spinous

as the

and arachnoid. At this juncture,

Simplifying

HINCK1

A

C

B

needle is then traversing the

processes,

and

further

advance,

of the

needle

bevel

C.

for

entering

the operator penetrates

the

dura

needle

after

arachnoid the

space

bevel

flow

removal has

of the

through

for

placement stylet to

of

the

position

osseous

the spinal

but

of

its

sub-

necessarily

the

orifice

that

subarachnoid

guide.*

needle

5 mm

There,

injected

familiar with surrounding

I have tip

while

D

sub-

into the extraarachnoid who perform spinal taps

as a depth canal.

the

the

partially penetrated the anachflow from the subarachnoid

or entirely half. All

needle,

from

that

not

within

injections are the uncertainties

to be used

fluid

indicates

entered,

only may

flow partly the other

subanachnoid To minimize

stylet

is entirely

one-half

stances may space through

cenebrospinal

the

been

needle

space. If the bevel has noid membrane, fluid space

of

of

with

this problem. the connect

designed

a blunt-tipped

It enables above rare

the

the

operator

floor

exception,

of

the

the

bevel

should lie entirely within the subarachnoid The manner in which this stylet is used

space (fig. is depicted

1).

figure 2 and described in the legend. Spinal taps for special neuroradiologic

procedures

on

this

servi’ce

are

generally

Example

performed

by house

officers

‘ii

with

Example

I

in

2

Fig. 2.-Example 1, Needle bevel straodling arachnoid in dorsal aspect of spinal canal. A, Stylet removed, spinal fluid flowing; B, blunt stylet inserted to full extent ; C, stylet advanced until stopped on floor of spinal canal; D, stylet withdrawn leaving needle tip 5 mm above canal floor. Example 2, Bevel straddling arachnoid in ventral aspect of canal. E, Stylet removed, spinal fluid flowing ; F, stylet introduced but not advancing to full extent (i.e., key and slot on hub do not engage completely), indicating needle tip near canal floor; G, stylet tip held gently but firmly against floor while needle withdrawn along stylet until key and slot engage; H, stylet withdrawn leaving needle tip 5 mm above canal floor. Stippled area=sub-

Arach fold

arachnoid

space.

various tions

levels were

guide C

o’-’ (_.

k?(?’#{176}t(

i,’

.‘#{149})“

i:;i.

Vertebralbody #{163}1 , -.,, c

.-,

-.

‘

, .

‘.‘l

Received

January

Department

C

Prototypes

Am

J Roentgenol

6. 1 976

;

of Radiology. were

provided

1 27 : 354,

accepted

after

Baylor

College

by

Cook,

1976

Inc

.-b’

procedure spinal

extends

April

of Medicine, Box

needle

C.

;

5 mm

blunt-

in at

beyond

489,

experience. before

Subsequently,

described

least

without

revision

.

concept.

and

common

been rare. In the exceptional identify a point at which the

‘1’’

,

Fig. 1 -A, Standard bevelled stylet ; B, standard tipped stylet which, when inserted to full extent, needle tip (D).

1

,‘l,

of skill

rather

400

Texas

Medical ltidiani

Center. 47401

354

Houston,

complication.

Texas

however,

77025.

injec-

of the

they

have

depth

actually

instance one can usually operator failed to follow the This

pneumoencephalograms

6, 1 976.

Blootitinytoti.

above.

Extraanachnoid introduction

technique

has and

been

used

myelograms