considered

a success

if objects are

severely

dis-

torted. smaller

or double.

Pneumatic

retinopexy

does not change

the

shape

of

the eye

nor interfere

with the extraocular

muscles: therefore

it has the

best chance

to restore

pre-detachment

vision. Sight

also returns

more quickly

following

PR than scle-

ral buckling.

allowing

patients

to return to their

nor-

mal lifestyle

faster. Pneumatic

retinopexy

(an office

procedure)

is much less costly

than scleral

buckling

(an OR procedure).

Pneumatic

retinopexy

may have

a lower

single

operation

success

rate than

scleral

buckling

for

some

types

of

retinal

detachments

(pseudophakic,

multiple

breaks,

more

extensive

areas

involved).

However,

several

authors

have

shown that

a failed

pneumatic

attempt does

not dis-

advantage

the eye

to ultimate

anatomic

and visual

success.

If

final

vision,

patient

morbidity,

and cost

are weighed

against

single operation

success,

pneu-

matic retinopexy

remains

a reasonable

procedure

to

try first.

Conclusion

Pneumatic

rcrinopcxy

is useful

for the treatment

of

selected

retinal

detachments

secondary

to retinal

breaks less

than

I clock

hour

in size

located

in the

upper two-thirds

of the fundus.

It has also

been suc-

cessfully

used

to

treat

retinal detachments

sec-

ondary

to multiple

retinal breaks separated

by up

to

180 degrees:

giant

tears: posterior

breaks,

including

macular holes: and

detachment

associated

with star

folds that do not exert

traction

on the retinal

breaks.

Multiple breaks,

pseudophakia,

and subretinal

fluid

greater

than

180

degrees

are

negative

prognostic

indicators

that will

lower

the

single operation

suc-

cess rate. However,

a pneumatic

failure

does not

disadvantage

the

eye

in

terms

of

a successful

anatomic

or visual

outcome. Pneumatic

retinopexy

offers the

advantages

of

minimal

tissue

trauma,

minimal morbidity,

rapid rehabilitation,

and

a sig-

nificant

reduction

in cost.

Pneumatic Retinopexy

41

Suggested Reading

Ambler JS.

Meyers

SM. Zegurra

H. et ul. Reoperations

and'

visual

results

after failed

pneumatic

retinopexy,

Oph-

r/wlmulogy

1990:97:7X6-79().

Boker T. Schmitt C. Muugharbcl M. Results and prognostic

tucrors in

pneumatic

rcrinopcxy.

Gcr J

Ophthalniol

199-i:3:73-7X.

Grizzard

WS.

Hilton

GF. Hammer

ME. ct

al. Pncum.uic

retinope xy failures.

Cause.

prevention.

timing. and

management.

Ophthulmolovy'

1995: 102:n9-936.

Hilton GF. Grizzard

WS. Pneumatic

retinopcxy:

a two-step

operation

without

conjunctival

incision.

Ophtliohnol-

ugy 1986:93:626.

Hilton

GF. Kelly

NE. Tornarnbc

PE.

et

al. Pneuruaric

retinopexy:

a cull.iborarive

report of the

first 100 cases.

Ophrh,rllIlulog." 1987:l)-il-i):307.

Lincoff A. Half

D. Ligg~[[

P. et

a!'

Iruravirrea! expanxion of

perfluorocarbon

gases. Arch

Ophthalmo!

19X():9X:I646.

Lincoff

H. Coleman

J. Kr~ssig

I. er al. The perfluorocarbon

Torn.unbe

PE. Pneumatic

rcrinopc xy: ThL' evolution

of C~I;-'t.:

sclccrion

~nd

surgical

rcchuiquc-c-A

twc]

vc-yc.ir study

of 302 eyes. Transactions

of the Amcruan

Ophthalrno-

lugic'ul

Socictv, Vol. XCV. December

1997.

Tornarnbe

PE. Grizzard

WS. cds. Pneumatic

Rrtinoprxv: r\

Clinical Symposium. Westport.

CT: Greenwood

Pub-

lishing: 1989.

Tornambe

PE. Hilton

GF

The

pneumatic

rerinopcx

y study

group.

Pncumutic

n.:rillopexy-A

rnulucenrcr

random-

ized controlled

clinical

tr ial

c<)lllparin~

pneumatic

r e tinopc

x y

with

sc icral

buck

l ing.

Oplnhulmol

19/i9;96:772-783.

Tornambe

PE. Hilton

GF. The

pneumatic

retinopexy

study

group.

Pneumatic

retinopexy-s-A

two-year

follow-up

study

of

the

multicenter clinical

trial comparing

pneu-

matic

retinopc xy

wi rh sclcrul

buckling.

Oplulralmo!

1991:98: 1115-1123.

Tornambe

PE. Hilton

GF. Kelly NE. et al. Expanded

indi-

cations

for

pneumatic

rerinop.uhy.

Ophthol.no!

I9/iX;95:5'!7,

In the last edition

of

this

book

I predicted

that

"reti-

nal surgeons

will

also be doing

more

local

and out-

patient surgery."

This certainly

is true. Today,

I do

more than 90%

of my

surgery

under

local

anesthe-

sia.

I have

h;.JJ one

inpatient

in 2 ye;.Jrs. Improve-

ments

in general

anesthesia and

local

sedation

have

aided

in

this

transition

to outpatient

surgery.

Patients usually

wake

up quickly

and

quietly

from

modern

general

anesthesia. Patients

do

better

at

home following

surgery where they

sleep

in their

own bed and are

cared

for by their

family.

Diabetic

patients

are usually

able

to

manage

their

own

insulin and medical

problems

at home.

There

are two

basic

approaches:

(I)

general

endotrachial

anesthesia

and (2) local

infiltration

or

nerve block

anesthesia.

The two techniques

blur

in

clinical practice.

Patients receiving local

anesthesia

are

often

sedated.

and

patients

receiving

general

anesthesia

are often

given

periocular

injections

of

local anesthetic

to decrease

the

required

depth

of

general

anesthesia

and

to aid with

post-operative

pain

management.

The selection

of anesthetic

tech-

nique

is difficult

for the

retinal

surgeon,

because

of

the emergent

nature

of

the surgery

and

the consul-

tative nature

of a retina

practice.

Often

the

patient is

referred away from

his usual medical

care

provider

and

the

patient's

medical

condition

is

not

well

known

to the surgeon.

Techniques

of

local

anesthetic

injection

have

changed

over the

last

10 years. The

Atkinson

tech-

nique ("looking

up and

in")

has fallen

into

disfa-

vor. Peribulbar

anesthesia involving

larger

volumes

of anesthetic

injected

away

from

the

globe is now

the most commonly

used

approach.

Minimalist

techniques

involving

topical anesthesia.

subcon-

juncti val injections,

and posterior

irrigation

have

been proposed

to di minish

the risk

of local

anes-

thesia. Bupivucaine

(Marcai ne ) is

now

the

most

commonly

used agent allowing

blocks

of

much

longer Juration.

New

drugs

for general

anesthesia

and new monitoring

devices

have.

likewise,

become available.

No one

anesthetic

technique

is right

for

every

patient

or

every operation.

Over

the

years

I have

developed

prejudices

about which

patients will

do

well with

local anesthesia

or local

anesthesia

sup-

plemented

by intravenous

sedation.

I have

devel-

oped

a

scoring system

to

select

patients

for local

anesthesia

(Table 6-1). Patients

with

a score

of

greater

than

three usually

do

better

with general

anesthesia

or

general

anesthesia

supplemented

with

local injection.

Numerous

factors influence

the selection

of an

anesthetic.

Which procedure

is being

done?

How

cooperative

is the patient?

How

familiar

is the

sur-

geon' with

the operating

environment

and the oper-

ating

room

personnel?

As

more

experience

is

acquired,

it is possible

to raise

your threshold

score.

After

a

few

bad experiences,

however,

it may

be

wise

to

lower

it for a while.

Table

6-1. Scoring

System

to Select

Patients

for

Local Versus

General

Anesthesia

.

Factor

Points

Procedure

Pneumatic retinopexy

0

Primary scleral buckling

I

"Easy" revision

of buckling

2

Diflicult

revision elf buckling

3

Simple vitrcctomy

2

Vitrccroruy

with

preretinal membrane

2

removal

or macular

hole

surgery

Vurcctomy

for cndophthalrnitis

3

Vitrectorny

for proliferative

4

vitrcorctinoputhy

(PYR)

or proliferative

diabetic retinopathy

Patient

Factors

Under age 60

I

Under age 40

2

Male

I

Trouble with

previous

local

eye surgery

2

Could not

tolerate

retinal examination

with

::

scleral depression

High myopia

2

Prefers general

.mc stheric

2

Severe cardiac

or respiratory

disease

-2

Patient just ate

-2

Operating

Room

Cunditions

Inexperienced

crew

in operaung

room

I

Excellent

anesthetic

department

I

Operating

at unfamiliar

hospital

1

Teaching situation

2

Surgeon

ju'sl out of

fellowship

2

Vitrectomy

and primary

scleral buckle

proce-

dures can usually

be done

with local

anesthesia.

Vitrectomies

can be done

with local anesthesia

more easily than

a scleral

buckle,

Complex

vitrec-

romies combined

with scleral

buckling

may need

general anesthesia

or general

anesthesia

supple-

mented

by

periocular

anesthetic

injection.

Endoph-

thalmitis

is a special

situation

because

it is difficult

to gel

,1

good

block

if there

is orbital

inflammation

(see

the

section

in this

chapter

on pharmacology).

If only

a tap

with injection

of antibiotics

is neces-

sary local

injection

may

be

adequate.

If vitrectorny

is going

to be

part

of

the

management

strategy,

I

.find that general

anesthesia

is frequently

necessary

and should be

available

if a local block

fails.

The most

important "patient factors" are

age and

the

ability

to

undergo

a good

retinal

examination

in

anesthesia.

Older

patients who have previously

had

cataract surgery

are

excellent

candidates for

local

anesthesia,

The environment

of the operating

room is also

important

in selecting

which

technique

to use. Sur-

new

hospital may

prefer

to have

the patient

asleep.

Operating

room

personnel

who

re;;pond,

"What's

that?" when asked

for every

instrument

can make

an experienced

surgeon

wish that

the

patient

were

asleep.

It is also

much

easier

to

teach

when

the

patient

is asleep!

In summary,

patient

selection

for

local anesthe-

sia is an

art. We have

all

found ourselves

in a situa-

tion

where

we

wished

we

had

made

the other

choice.

Table 6-1

and

a

little experience

will,

it

is

hoped, minimize

those

situations.

Anatomy

To safely

provide

regional

anesthesia

for ocular

surgery,

it is necessary

to

have

a thorough

knowl-

edge

of orbital

and

periorbital

anatomy

and

to

understand

the

anatomic

changes

that

take

place

during ocular movement.

The

anterior orbit

is occupied

by

the

eye. which

geometrically

is a modified

sphere

or two

merged

spheres,

one in front

of

the other. The emmetropic

eye has

an anteroposterior

diameter

of approxi-

mately

24 mm and a vertical

diameter

of 23 rnrn. In

myopia, the eye is larger with a more elongated.

ovoid

shape.

In

eyes

with

more

than 4-diopters

of

myopia,

the axial

length

varies

from

26.7

to

31.0

mrn.

A

line joining

the

medial

and lateral

orbital

margins

will have

a third

of the

eye anterior

to it.

The lateral orbital rim

is more

posterior

than

the

medial

orbital

rim. The

equator of

the

eye is gener-

ally at, or slightly

anterior

to, the

lateral

orbital

rim.

The eye is closer

to

the

roof of the orbit

than to the

floor and the frontal

bone

overhangs

the

eye, mak-

ing

the

inferoternporal

approach

the

most

open

access

to the retrobulbar

space.

The

concept

of

a

well-defined

muscle

cone

formed

anteriorly

by

the

coronal

circumference

of

the

eye

and posteriorly

by the rectus

muscles

with a

well-developed

intermuscular

septum

has

been

shown

to

be

not

only

a simplification

but

inaccu-

rate. Anteriorly,

there

are

well-formed

connective

tissue septa connccring

the ocular

muscles;

posteri-

orly. however,

the

intermuscular

septum

becomes

less well defined

and more

complex

connective

tis-

sue septa appear. Two

poorly

septated

areas

in

the

orbit. one lateral

to

the

optic nerve

and

the

other

above

the superior

ophthalmic

vein

hammock,

account

for the high

success