Topical versus peribulbar anesthesia in clear corneal cataract surgery

M. Zehetmayer, MD, U. Radax, MD, Ch. Skorpik, MD, R. Menapace, MD, M. Schemper, PhD, H. Weghaupt, MD, U. Scholz, MD

ABSTRACT

Purpose: To evaluate the efficacy of topical anesthesia as an alternative to peribulbar anesthesia in clear corneal cataract surgery.

Setting: Department of Ophthalmology, University of Vienna, Austria.

Methods: In this prospective, double-blind clinical trial, 36 patients had bilateral cataract surgeries performed from 1 to 3 months apart. Half of the patients had topical anesthesia for the first surgery and peribulbar anesthesia for the second surgery. The other half had peribulbar first and then topical. All surgery was done using a temporal clear corneal approach and bimanual phacoemulsification fol­lowed by in-the-bag intraocular lens implantation. Subjective pain was assessed using a visual analog scale of no pain (O%) to worst pain imaginable (100%) and intraoperative motility using a rank scale of adverse motility (-5) to ideal patient cooperation (+5).

Results: Subjective pain was comparable whether topical or peri bulbar anesthesia was used (mean 10.75 versus 10.97%; P > .6). Patient cooperation (motility) was significantly better when topical anesthesia was used (+2.16 versus +1.11; P =

.03). There were no significant differences in complications. A peribulbar block was given in addition to the topical anesthesia in two cases.

Conclusions: Topical anesthesia is a safe, effective alternative to peribulbar anesthe­sia in clear corneal cataract surgery. J Cataract Refract Surg 1996; 22:480-484

Peribulbar anesthesia was introduced in 1986 as a safe

and effective alternative to retrobulbar injections. 1,2

However, several complications have been reported in

the literature, including globe perforation, severe orbital

hemorrhage, optic nerve trauma, retinal vascular occlu­

sion, intravascular injection, and muscle dysfunction.3

The application of topical anesthesia in eye surgery dates back to 1884, when Koller4 used 5% cocaine for cataract extraction. In the early 1990s, Fichman reintro­

duced topical anesthesia for use in small incision phaco­

emulsification ("Topical Eyedrops Replace Injection for

Anesthesia," Ocular Surgery News, March 1, 1992,

pages 1,20-21). Subsequent research has shown that

topical anesthesia may be better than regional anesthe­

sia, especially in combination with self-sealing clear cor­

neal incisions.5 Topical anesthesia greatly reduces the

risk of complications and eliminates those stemming

From the Department of Ophthalmology (Zehetmayer, Radax, Skorpik, Menapace, Weghaupt, Scholz) and Department of Medical Computer Sciences, Clinical Biometry (Schemper), University of Vienna, Austria.

Presented in part at the Symposium on Cataract, JOL and Refractive Surgery, Boston, April 1994.

Reprint requests to M. Zehetmayer, MD, Department of Ophthalmol­ogy, University of Vienna, Wiihringergiirtel 18-20, A-1090 Vienna, Austria.

480 J CATARACT REFRACT SURG-VOL 22, MAY 1996

TOPICAL VERSUS PERIBULBAR ANESTHESIA

from the needle and systemic toxicity. Yet, concerns still

exist including those related to incomplete akinesia and

patient discomfort.

We compared the effect of topical and peribulbar

anesthesia on subjective pain and ocular motility during

clear corneal cataract surgery.

Subjects and Methods This prospective, randomized, double-blind clinical

trial comprised consecutive patients from January to

September 1993 who agreed to bilateral cataract extrac­

tion with surgeries 1 to 3 months apart. Excluded were

patients with barriers to communication or cooperation

during surgery (e.g., extreme anxiety, language, hearing impairment, mental retardation, dementia, Parkinson's

disease, very young) and those with previous retinal sur­

gery or severe active diabetic retinopathy.

Patients were randomly assigned to one of two study arms. In the first arm (n = 18), topical anesthesia was

used during the first surgery and peribulbar anesthesia

during the second. In the other arm (n = 18), peribulbar

anesthesia was given first and topical second. Table 1

shows patient demographics. There were no statistically

significant differences between groups in age, sex, or

time between surgeries.

Variability estimates for the primary response crite­rion (subjective pain) were not available before the study

began. Therefore, sample size was determined based on

variability observed in the first 12 cases (Cox's half sam­

piing). This calculation resulted in 36 total patients. A t-test was done to analyze the treatment effect in a cross­

over study using the STPLAN program.6 The compu-

Table 1. Patient demographics.

Study Arm

Topicall Peribulbarl Variable Peri bulbar Topical

Age in years (mean ± SO) 73.9 ± 7.1 71 .8 ± 9.8 Sex

Male 6 9 Female 12 9

Pre-existing pathology Diabetes 2 2 Glaucoma 0 Bronchial asthma

tation was based on a two-sided alpha level of 5%, 95%

power to detect an existing treatment effect of8% on the

visual analog pain scale and an observed MS of 174 error

(i.e., the respective pooled variance within comparison

groups).

The day before surgery, patients were told the de­

tails of the surgical procedure except what type of anes­

thesia they would receive. They were told that they might have minimal discomfort. One hour before sur­

gery, patients received oral sedation of 400 or 800 mg of

meprobromate, with the dose depending on age, weight,

and anxiety level. The dose for each patient was the same

for both surgeries. Mydriasis was obtained by phenyl­

ephrine hydrochloride, tropicamide, and cyclopentolate

combined with topical indomethacin.

In the operating room, patients received one drop of

1 % oxybuprocaine and povidone-iodine. The assisting

physician administered the topical or peribulbar anes­

thesia with the surgeon not present.

Topical anesthesia consisted of two to three drops of

4% lidocaine hydrochloride placed in the conjunctival

sac. This procedure was repeated three times at 3 to

5 minute intervals. Peribulbar anesthesia consisted of a

5.0 cc mixture of2.5 cc 2% lidocaine (Xylanest® purum

2%) and 2.5 cc 0.5% bupivacaine (Carbostesin® 0.5%)

combined with 750 IU hyaluronidase. The injection

was given 10 minutes before surgery using a one-site,

inferotemporal, transconjunctival approach and a stan­

dard sharp, 0.75 in, 26 gauge needle. Mild digital pres­

sure was applied to the injection site and to the globe for

1 to 2 minutes to help disperse the anesthetic and pre­

vent peri bulbar hemorrhage. Surgery, identical in all eyes, comprised a temporal,

two-plane, 3 mm wide clear corneal incision, side-port paracentesis, 5 mm continuous curvilinear capsulo­

rhexis, and cataract extraction by bimanual endocapsu­lar phacoemulsification. The clear corneal incision was enlarged, when needed, to a maximum of 5 mm. Then,

a foldable silicone small-optic poly(methyl methacry­

late) intraocular lens (IOL) was implanted in the bag.

During surgery, patients were asked to fixate on the

operating microscope light.

Clear corneal incision width varied from 3 to 5 mm

and was the same for both surgeries in all but one pa­

tient. In this patient, the first surgery was uncomplicated and a foldable IOL was implanted through a 4 mm clear corneal incision. Mter a posterior rupture with vitreous

J CATARACT REFRACT SURG-VOL 22, MAY 1996 481

TOPICAL VERSUS PERI BULBAR ANESTHESIA

loss occurred during the second surgery, the incision was

enlarged to 5 mm for insertion of a sulcus-placed, rigid

IOL. In 89% of patients, the same surgeon from a group

of three operated on both eyes. In 94%, the same im­

plantation technique (forceps or injector) was used. Be­

cause of the double-blind nature of our study design, the

surgeon was not aware of the kind of anesthesia admin­

istered, and verbal communication between surgeon

and patient was limited to the necessities.

Mter surgery, the surgeon ranked intraoperative

motility on a scale ranging from - 5 (adverse motility) to

+ 5 (ideal patient cooperation). Adverse motility was

defined as ocular movement that interfered with surgery

(e.g., unwanted turning of the eye, loss of fixation, in­

advertent blinking with or without Bell's phenomenon). About 15 to 45 minutes after surgery, a third person

assessed subjective pain using a visual analog scale7 rang­

ing from 0% (no pain) to 100% (worst pain imagin­

able). All records and charts were evaluated for

intraoperative complications or unusual postoperative

findings, with special attention given to whether an an­

algesic was given within the first 24 hours.

Effects of the anesthesia procedure (treatment ef­

fect) and of the sequence of the procedure (period ef­

fect) , as well as the carryover effect on the primary

(subjective pain) and secondary (motility) response cri­

teria (Table 2), were estimated and tested for signifi­

cance by the analysis of variance model for the 2 X

2 crossover as described by Jones and Kenward.s These

analyses were supplemented by corresponding nonpara­

metric tests. The underlying treatment effects were fur­ther characterized by 95% confidence intervals.

Criterion

Subjective pain effect

Treatment (peri bulbar minus topical)

Period (second minus first eye)

Motility Effect

Treatment (peribulbar minus topical)

Period (second minus first eye)

P-value Parametricl

Size of Effect Nonparametric

0.22 % 0.94/0.63

4.39 % 0.16/0.13

-1.05 0.03/0.03

0.17 0.72/0.71

Statistical analyses were based on SAS/STAT computer

prograrns9 (GLM and NPARIWAy).

Results Subjective pain ratings were similar whether peri­

bulbar or topical anesthesia was used. The mean subjec­

tive pain rating was 10.75% ± 11.00 (SO) for the

topical group and 10.97 ± 15.30% for the peribulbar

group, a statistically nonsignificant difference of 0.22% (P> .6).

There was, however, a statistically significant differ­

ence (P = .03) between the two anesthesia groups in

intraoperative motility. Mean motility was 2.16 ± 2.80 in the topical group and 1.11 ± 2.50 in the peri­

bulbar group.

The 95% confidence intervals for treatment effects on subjective pain and motility were -4.12 to 4.56 and

-1.71 to -0.39, respectively. For both crossover anal­

yses, the possibility of a carryover effect was checked but

carryover was virtually nonexistent (all P> .65), permit­

ting the interpretation of treatment and period effect.

An orbital hemorrhage developed in one peribulbar

case, interfering with surgery. In two topical cases, the

surgeon administered a peribulbar block during surgery

because of pain and adverse motility. Although no addi­

tional blocks were given in the peribulbar group, the

difference between groups was not statistically

significant. The posterior capsule tore in two cases in each

group. Three tears were small and because the anterior

hyaloid membrane remained intact, in-the-bag IOL im­plantation was still possible. In the other case, a vitrec­

tomy had to be done and the IOL inserted into the sulcus. This eye had been scheduled to have surgery

using peribulbar anesthesia. Three patients who had peri bulbar and one who

had topical anesthesia asked for an analgesic within the first 24 hour postoperatively.

Discussion This clinical trial reflects our experience during the

first year after instituting topical anesthesia. The study

was of a crossover design to permit precise evaluation of

subjective pain, a phenomenon that is otherwise subject to high variability among patients. The results indicate

that topical anesthesia with 4% lidocaine offers the same

482 J CATARACT REFRACT SURG-VOL 22, MAY 1996

TOPICAl VERSUS PERIBULBAR ANESTHESIA

pain alleviation as one-site peribulbar anesthesia for

temporal clear corneal cataract surgery.

We used the transconjunctival route for the peri­bulbar injection. There is strong evidence that the sub­

jective pain could be even higher when a percutaneous route is used for peribulbar injection. 10

Of the few comparative studies on subjective pain

during cataract surgery, most deal with retrobulbar and 'b lb h . 11-14 I . pen u ar anest eSla. n a prospectIve, nonran-

domized study on topical and retrobulbar anesthesia,

Kershner5 found that topical anesthesia is as effective as

a retrobulbar injection for intraoperative analgesia. He

used 0.5% tetracaine as the topical anesthesia.

We administered 4% lidocaine for topical anesthe­

sia because when we used 0.5% tetracaine or 4% cocaine

in a previous group of patients, corneal transparency was

significantly compromised, especially in the second half

of surgery. This complication may be related to the cor­

neal toxicity of these anesthetics. Lidocaine is reported to be less toxic. 15

One important aim of ocular regional anesthesia is

good bulbar akinesia, which had been considered essen­

tial to successful surgery until recently. Yet most studies

of topical anesthesia for cataract surgery report that eye

movements are easily controlled and that patient­controlled eye movements are sometimes helpful. 16

Thus, we used a two-sided rank scale to assess intra­

operative ocular motility, allowing evaluation of both adverse and advantageous motility. The results were sig­

nificantly better when topical anesthesia was used. Un­

compromised motility with the possibility of active

fixation and patient cooperation seems an important benefit. However, adequate pain alleviation is essential

when topical anesthesia is used because patient-con­trolled globe stabilization and ocular movements are

possible only if the patient feels no pain.

In two patients in the topical group, an additional peribulbar block was given intraoperatively because of pain and adverse motility. The valve mechanism of the

clear corneal incision provided a stable anterior segment,

allowing easy injection of the peribulbar anesthetic.

Topical anesthesia avoids several potential compli­

cations of retrobulbar and peribulbar anesthesia.

Although the relative risk is small, iatrogenic complica­

tions do occur. Possible disadvantages of topical anes­thesia include adverse eye movements and that not all

patients are suitable candidates for the technique.

In our clinical trial, we excluded only patients with

extreme anxiety or a language barrier or those unable to

communicate or cooperate with the surgeon. Applying more rigorous exclusion criteria and intensive verbal an­

esthesia should improve our favorable topical anesthesia

results.

On the basis of our experience, we estimate that

80 to 90% of cataract patients are eligible for surgery

using topical anesthesia. Patients who could especially

benefit from this technique are those who have had pre­

vious eye surgery or those with severe myopia, ischemic

ocular disease, or coagulopathy.

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