Efficacy and complication rate of 16,224 consecutive peribulbar blocks

Efficacy and complication rate of 16,224 consecutive peribulbar blocks A prospective multicenter study David B. Davis II, M.D., Mark Richard Mandel, M.D.

ABSTRACT Although usually safe, retrobulbar anesthesia and peribulbar anesthesia have potentially sight- and life-threatening complications. Although it has been suggested that peribulbar anesthesia is as effective and safer than retrobulbar anesthesia, no large study has addressed the true rate of complications. To determine the efficacy and safety of peribulbar anesthesia, this study prospectively examined 16,224 consecutive peribulbar blocks. Twelve centers in the United States, Germany, and Chile participated in the study. After a peribulbar block was administered, the degree of akinesia, amaurosis, percentage of supplemental blocks required, and side effects and complications occurring after the block and for six weeks were recorded. Perioperative and late optic nerve complications were included. To approximate a real-life situation, ophthalmologists, anesthesiologists, and certified registered nurse anesthetists performed the blocks. Ninety-five percent of patients achieved a 95% or greater degree of akinesia. The incidence of complications in the consecutive cases was low. Orbital hemorrhage occurred in 12 cases (0.74%). There was one globe perforation (0.006%), two expulsive hemorrhages (0.013%), one grand mal seizure (0.006%), and no cases of cardiac or respiratory depression or deaths. Peribulbar is as effective as retrobulbar anesthesia and appears to lead to fewer sight- and life-threatening complications, even when slightly different peribulbar techniques are used. This is especially true when the anesthetic is administered with a 11/4-inch or shorter needle with the eye in the primary position, followed by ten to 15 minutes of ocular compression.

Key Words: complication, peribulbar anesthesia, prospective study, retrobulbar anesthesia

Since Knapp 1first described the retrobulbar injection more than 100 years ago, it has been used extensively in ophthalmology. Until the 1980s, the only alternative to retrobulbar anesthesia was general anesthesia. Although extremely safe, retrobulbar anesthesia has serious side effects and complications. Side effects include pain upon injection and the need to cancel a case because of a retrobulbar hemorrhage. 2- 7 Sight-threatening complications such as optic nerve damage, 2·5•8 •9 central retinal artery occlusion, 10•11 embolization of material into retinal and choroidal circulation, 5 and globe perforation12-16 can occur. Life-threatening systemic disasters such as cardiac arrest, respiratory depression, central nervous system (CNS) depression, and seizures also occur.4,17-33 Although "1 00% safe anesthesia" cannot exist, it is

important to strive for this goal. In the classic retrobulbar injection the needle passes close to the equator of the globe into the immediate retrobulbar space, in close approximation to the posterior globe, the optic nerve, central retinal artery and vein, and dural sheath. Mechanical or toxic trauma to any of these structures can result in severe damage. Theoretically, an injection that does not violate this space should result in a lower incidence and a narrower spectrum of complications and side effects than one that does (i.e., retrobulbar anesthesia). Peribulbar anesthesia attempts to avoid these structures and the subarachnoid space by placing the anesthetic outside the retrobulbar space just posterior to the equator of the globe, allowing diffusion of the anesthetic agents to achieve orbital anesthesia and akinesia. 34·35

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A number of relatively small single-center studies age range, number of supplemental blocks required, have delineated the technique and safety of peribulbar number of seventh nerve blocks required, and complianesthesia. 34- 48 Isolated complications of peri bulbar cations that occurred within six weeks. Each center colblocks such as globe perforation, 13 • 14 ·49 - 51 acquired lected side effect and complication data for six weeks Brown's syndrome, 52 and contralateral amaurosis 53 after surgery so no subacute optic nerve complication have been described. In these reports, however, the total was excluded. number of blocks was not available, thus the rate of The block's overall efficacy was determined in three complications could not be calculated. To date, no large ways. First, each study center tabulated the percentage prospective study has examined the efficacy or safety of of supplemental deep blocks required. Second, eight peribulbar anesthesia. centers subjectively estimated the degree of akinesia folThis prospective, nonrandomized study of peri bulbar lowing the block. Third, the percentage of supplemental anesthesia was designed to determine whether peribul- seventh nerve blocks was assessed. bar anesthesia is effective and safe and to delineate the Akinesia was defined as 100% if there was absolutely exact nature of the complications and side effects and no globe movement after the block. Each of the four their rate of occurrence. quadrants of movement was assigned a maximum value of25%. Ifthe patient exhibited complete movement in SUBJECTS AND METHODS one field of gaze, the block was considered 75% effective. This study, conducted from January 1988 to January If only partial movement remained in any one direc1992, consisted of 16,224 consecutive patients who had tion, 5% was subtracted from the total. The methods of peribulbar anesthesia at 12 facilities in the United States, determining effectiveness of the block are highly subChile, and Germany (Appendix). Of the blocks, 15,404 jective. However, in a clinical study of this size, there were given for intraocular surgery and 820 for nonin- are no practical objective means of assessing degree of traocular ophthalmic procedures. Once a physician or akinesia. Table 2 lists the exact technique each center used, center began participating in the study, all cases were including needle type, anesthetic solutions, location of tabulated with no patients excluded. Table 1 lists the injection site, and training of the person administering consecutive total number of cases performed at each the blocks. Injection technique varied slightly among the center and the types of cases that received the peri bulbar participating centers. The main variables included neeblock. dle configuration, injectate composition, and whether At the end of each month, statistics from each center or two deep injection sites were employed. Only one one were forwarded to the study center in Hayward, California. These included number of patients, type of sur- center used a seventh nerve block. To approximate the gery performed, male-to-female ratio, average age and real world, the study was designed to include variously Table 1. Case breakdown by center. Researcher

Total

ECCE*

KPEt

ICCE

Secondary IOL

Trabeculectomy

Other

Non

1-0

Neuhann et a!.

2,388

12

57

50

33

3

2,168

0 427

2,163

Davis/Man del

1,612

2

33

59

34

1

0

Bloomberg et a!.

1,886

2

1,706

0

0

20

129

1,733

0

1,612

0

57

19

14 45

15

Arnold

0

0

Benson**

1,452

184

804

0

4

111

202

0

147

Smith**

1,440

1,379

0

0

26

0

34

1

0

Thornton

1,269

859

312

0

2

0

0

0

96

Neumann

1,021

0

10

0

2

2

387

1,149

0 876

620

Fier et a!.

221

0

52

0

0

0

0

Manger/Devlin

711

2

704

0

5

0

0

0

0

Weiss/Barrack

548

0

355

0

41

86

33

0

Oyarzun/Luck

459

380

0

0

8

0

33 13

13

58

* Includes ECCE, ECCE with trabeculectomy t Includes phacoemulsification, phacoemulsification with trabeculectomy t Includes penetrating keratoplasty (PKP), PKP with ECCE §Other intraocular (1-0) includes vitrectomies, IOL exchanges, wound revision, IOL manipulation, trauma . Includes radial keratotomy, IOL reposition, strabismus, pterygium ** Two-injection technique

328

1-0§

PKPt 70

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Table 2. Technique and materials used at each center. Needle Type Researcher

Gauge (Inches)

Anesthetic Solution

Injection Location*

Preinjection No

Neuhann et al.

Sharp disposable 26 (7/s)

0.5% bupivacaine 300 IU hyaluronidase

IT

Benson*

Sharp disposable 25 (I)

2% lidocaine/ epinephrine

IT SN

Davis/Mandel

Modified point 5 cc 0.75% bupivacaine 4 cc I% lidocaine 23 or 25 (3/4 to I) 0.3 cc hyaluronidase

Ocular Who Gave Compression Blockt

Miscellaneous

Honan balloon 30 minutes

A

Super-Pinkie <20 minutes

c

No oral or IV sedation

Tranxillium 20 mg p.o. (70%) up to 10 cc

IT

Yes 4:1 BSS/ lidocaine

Super-Pinkie <30 minutes

B

IV midazolam PRN, 6-10 cc

Super-Pinkie I hour

D,B

IV fentanyl I 00% methohexital sodium

A

Hydroxyzine 35 mgm I m IV sedation in 5%, 6 cc

Neumann

Blunt 23 (llh)

2.5 cc 4% lidocaine 2.5 cc bupivacaine 0.5 cc hyaluronidase

IT

Yes 9:1 BSS/ lidocaine

Thornton

Thornton 25 (I)

I : I 4% lidocaine 0.75% bupivacaine 0.2 cc hyaluronidase

ST

Yes Soft rubber 9:1 BSS/ 30-35 minutes lidocaine

25 (I)

6 cc 0.75% bupivacaine 4 cc 2% lidocaine 75 IU hyaluronidase

IT SN

No

Honan balloon

D

IV pentobarbital (75 mg)

Oyarzun/Luck

25(5/sto I)

0.5% bupivacaine 1.8 2% carb/adrenalin 75-150 IU hyaluronidase

IT

No

Honan balloon 50:50 Mercury bag 10+ minutes

A

Bronazepan p.o. 100%

Bloomberg et al.

Prec Glide sharp 25 (I)

0.75% bupivacaine 2% lidocaine

IT

No

Honan balloon 20-30 minutes

D

IV methohexital, midazolam fentanyl 10%, 5-10 cc for supplementation

Fier et al.

Prec Glide sharp 23 (Ph)

I : I 2% lidocaine 0.75% bupivacaine

IT

No

Honan balloon I hour

B

IV midazolam and fentanyl

Smith*

Arnold

Sharp 23 (I)

I: I lidocaine hyaluronidase

IT

No

Honan balloon 10 minutes

A

IV methohexital, 3-8 cc; average 5 cc

Weiss/Barrack

Sharp 25 (5fs)

I: I lidocaine 150 IU hyaluronidase

IT

No

Honan balloon 10-20 minutes

A

IV midazolam 45% of time

Manger/Devlin

Atkinson 25 (7/s)

6 cc 0.75% bupivacaine 4 cc I% lidocaine 150 IU hyaluronidase

IT

No

Honan balloon 15-20 minutes

A

IV methohexital by B, 10 cc supplement 2% lidocaine IV

* IT = inferotemporal, SN = superonasal, ST = superotemporal t A = M.D. ophthalmologist, B = M.D. anesthesiologist, C = D.O. anesthesiologist, D * Two primary injections given

trained personnel performing blocks with slightly different peribulbar techniques. A representative example of an injection technique is that of Davis and Mandel, who used a superficial and a single, deep injection. In the technique, a 2 cc "preperibulbar'' injection of warmed 9:1 to 4:1 1% lidocaine: balanced salt solution (BSS®) is given superficially in the orbicularis and anterior orbit with a 27-gauge, 1/z-inch disposable needle. This should not be considered a seventh nerve block as the dilute solution is given in a small amount (0.5 to

= C.R.N.A.

1.0 cc) and lasts only five to ten minutes. This injection merely anesthetizes the skin and lids to the larger needle (23 gauge to 26 gauge) and more painful full-strength anesthetics given for the periocular injection. It is delivered transcutaneously at the junction of the medial two-thirds and lateral third oflower eyelid just above the orbital rim. The deeper peri bulbar injection is then administered with a 23-gauge Thornton needle (Alcon 8065-4206-01) or modified-point needle, 3/4-inch to l-inch long, through the inferior-temporal lid using a warmed (98 de-

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gree) mixture of 6 cc ofO. 75% bupivacaine, 3 cc of 1% lidocaine, and 1 cc of hyaluronidase. The eye is maintained in the primary position. The total volume of the peribulbar anesthetic injection is approximately 4 cc to lO cc (average 8 cc). The eyelid is then closed and a Super-Pinkie compression device placed for a minimum of ten minutes (optimum time often to 25 minutes). After eight to ten minutes, the block is evaluated. If a supplemental injection is required, the same peribulbar needle is used and the solution given through the inferonasal or superonasal lid or conjunctiva.

RESULTS This study was composed of 16,224 consecutive patients without exclusion (Table 1). Average age was 73.4 years. The female-to-male ratio was 10.0:6.2. Although no attempt was made to grade or objectively evaluate degree of anesthesia because of the large number of centers and different techniques used, we did evaluate discomfort in 200 consecutive patients by having patients fill out a questionnaire the day after surgery. Seventy percent remembered having had the injection; 30% did not. Of the 140 patients who remembered, only two stated they had severe pain; neither received any systemic sedation. Seven (5%) reported moderate discomfort. Ninety (64%) had no discomfort, and theremaining 41 (29%) noted mild discomfort. This group was not broken into patients who received systemic medication and those who did not, but this will be addressed in a future study.

Degree of Amaurosis

Because patients receiving a peribulbar block usually do not become amaurotic, 34 •35 •54 we used percentage of amaurosis as an internal control to ensure that the injections truly represented peribulbar blocks. The presence of amaurosis was determined by assessing the perception of hand motions after the block but before surgery. This is a clinical method of determining whether an intended peribulbar block resulted in an inadvertent retrobulbar block with interruption of optic nerve conduction. Three centers were selected to study the degree of amaurosis (Table 3). Of 5,506 consecutive patients evaluated in this substudy, 1.3% developed amaurosis, confirming that peribulbar blocks do not interrupt optic Table 3. Degree of amaurosis substudy data.

Researcher

Cases

n (%)

Davis/Man del Benson*

2,168

43 (2.0)

1,452

5 (0.3)

Bloomberg et al.

1,886

28 ( 1.5)

330

Efficacy of Block

Only one study center (Table 4) performed a seventh nerve block routinely. In the other centers, an additional seventh nerve block was required in only 1. 76% of cases. The supplemental block rate for the peribulbar injection was broken into centers using two primary deep injections (Benson and Smith) and those using one primary deep injection (remainder of participants). The supplemental injection rate for the center administering two injections was 7.8% and for the remaining participants, 5.0%. There was a noticeable trend toward a decreasing percentage of supplemental injections required with increasing experience administering the block. Table 5 shows the effectiveness of the block as gauged by degree of akinesia; 95.4% of patients achieved akinesia greater than 95%. One center (Davis/Mandel) was selected to further break down subjective estimation of akinesia. Of 2,168 consecutive cases, 95.4% had a greater than 98% block, and an additional 2.1% had a 95% to 98% block, resulting in 97.5% patients with a block of95% or more. Fewer than 2.4% of blocks were rated as a final akinesia ofless than 95%. In the 53 cases achieving less than 95% akinesia, positive posterior pressure was not manifest intraoperatively, and the residual muscle activity caused no problems or complications during surgery. The surgeons were masked as to the Table 4. Supplemental blocks by center.

Injection Single Neuhann et al. Bloomberg et al.

Blocks 2,388 1,886

Additional Supplemental Nerve Block n (%) n 80 (3.4) 134 (7. I)

0

17 (9.8) 191 (8.8)

0 38* 0 0

0

Arnold

1,733

Davis/Mandel

2,168

Thornton

1,269

Fier et al.

1,149

21 (I. 7) 63 (5.5)

711

15 (2.1)

0

Weiss/Barrack

548 459

6 ( 1.1) 47 (10.2)

0

Oyarzun/Luck

1,021 -13,332

87 (8.5) 661 (5.0)

921t 959

Two Benson

1,452

72 (5.0)

0

Smith

1,440

154 (10.7)

0

2,892 226 (7.8) *Equals 1.8% of center's total blocks t Performed VII nerve block routinely

0

Manger/Devlin

Neumann

Amaurosis

* Two-injection technique

nerve function and indicating that more than 98% of blocks were peribulbar and not retrobulbar. None of the patients not achieving amaurosis complained of the brightness of the microscope light.

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Table 5. Degree of akinesia; eight-center substudy Injection

Blocks

>95% Block(%)

2,388 2,168 1,269 1,021 711

2,250 (94.2) 2,107 (97.2) 1,206 (95.0) 925 (90.6) 649 (91.3) 548 (100.0)

Single Neuhann et al. Davis/Mandel Thornton Neumann Manger/Devlin Weiss/Barrack Oyarzun/Luck Subtotal

548 459 -8,564

435 (94.8) 8,120 (94.8)

Two Smith Total

1,440 10,004

1,428 (99.2) 9,548 (95.4)

degree of akinesia, which was determined and recorded by the anesthesiologist delivering the block.

Peribulbar Block Complications

Table 6 shows the incidence of complications in the 16,224 consecutive peribulbar cases. Cancellation ofCase. Three cases (0.018%) had to be cancelled after the block but before starting surgery. One case was cancelled due to the grand mal seizure discussed below. Another case was cancelled because of an intraocular hemorrhage caused by the placement of a superior rectus bridle suture, not by the block. One case, cancelled because of a severe orbital hemorrhage, occurred in a patient on hydroxycoumarin therapy that was not discontinued before the block. An inferotemporal approach with a 23-gauge, l-inch sharp needle was

Table 6. Incidence of complications in 16,224 consecutive peribulbar cases. Complication Cases canceled Orbital hemorrhage

Number

Percentage

3 12

O.Ql8

0.074 Positive pressure 9 0.055 Globe perforations 0.006 Central retinal vein occlusion 0.006 Ischemic optic neuropathy 1 0.006 Expulsive hemorrhage* 2 0.013 Acute intraoperative 0.006 suprachoroidal hemorrhage CNS complicationt 1 0.006 Cardiac/respiratory depression 0 * Both occurred during penetrating keratoplasty (i.e., two in 15,404 intraocular surgeries); none occurred in 14,232 cataract/ IOL surgeries t One grand mal seizure

used. Surgery was performed uneventfully using the same peribulbar technique at a later date. Orbital Hemorrhage. Ten additional significant peribulbar hemorrhages occurred following injection of the anesthetic. All eyes responded well to ocular compression and had cataract surgery the same day without incident. No posterior pressure was noted during surgery in any of these cases. There was one additional significant peribulbar hemorrhage that apparently occurred during cataract removal and intraocular lens {IOL) insertion. A 23-gauge, 1112-inch, flat ground needle had been used for peribulbar anesthesia. After insertion of the IOL, marked posterior pressure was noted. After the drapes were removed, a large peribulbar hemorrhage with swelling of the upper and lower lids and proptosis of the globe was noted. The patient achieved 20/20 visual acuity. Out of 16,224 total cases, 12 orbital hemorrhages (0.074%) occurred. Positive Posterior Pressure. Nine cases (0.055%) required a vitreous tap to complete the procedure because of excessive positive posterior pressure. All cases had uneventful cataract removal and IOL insertion. No signs of orbital hemorrhage were noted in any case. Globe Perforation. One globe perforation (0.006%) occurred in an 85-year-old male with an axial length of 23.56 mm. The technique used was a primary twoinjection peribulbar block given superonasally and inferotemporally with a 25-gauge, l-inch sharp needle. During the cataract procedure, the surgeon noted that the globe was markedly hypotensive. Surgery proceeded without difficulty. At the end of the case, a dense vitreous hemorrhage was found by indirect ophthalmoscopy. Postoperatively, the vitreous hemorrhage cleared quickly and at six weeks, uncorrected visual acuity was 20/30. A retinal specialist noted a single puncture site in the superonasal quadrant halfway between the equator and the ora serrata, which was treated with cryopexy. No retinal detachment occurred. Central Retinal Vein Occlusion (CRVO). One CRVO (0.006%) occurred within six weeks postoperatively in an 86-year-old female who had combined phacoemulsification and trabeculectomy for uncontrolled glaucoma. The patient's final visual acuity was 20/200. She had developed a central retinal vein occlusion in her nonoperative contralateral eye before this surgery. Acute Ischemic Optic Neuropathy (A/ON). One case of AION (0.006%) occurred within the six week postoperative period in an 87-year-old female with hypertension and significant fluctuations of blood pressure before surgery. A 26-gauge (23 mm) sharp needle was used with 0.5% bupivacaine with 300 IU of hyaluronidase. The phacoemulsification and IOL implantation was somewhat "difficult due to congested orbital contents and positive vitreous pressure." On the second postoperative day, visual acuity was 20/30 and "mild disc pallor was noted." Within one month, the visual acuity had dropped to 20/200 and there was "marked swelling of the superior disc margin" with an "inferior

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attitudinal defect." By the second postoperative month, the disc was pale temporally and superiorly with distinct disc margins. One case of postoperative visual "snuff out" (0.006%) occurred within the first six weeks in an 80-year-old male with severe primary open-angle glaucoma who had combined phacoemulsification/IOL implantation and trabeculectomy surgery. Before surgery, the patient had a large relative afferent pupillary defect and an intraocular pressure (lOP) of 26 mm Hg on maximum medical therapy. Preoperative vision was counting fingers at one foot, but the patient had a dense cataract. Surgery was uncomplicated and the peribulbar block was given with a 23-gauge, l-inch sharp needle by the inferotemporal lid approach, with a total volume of approximately 6 cc of a bupivacaine, lidocaine, and hyaluronidase mixture. Postoperatively, the lOP was controlled between 5 mm Hg and 11 mm Hg, but vision dropped to light perception on the first postoperative day and remained at this level on all subsequent examinations. The preoperative cup-to-disc ratio was 0.9+. There was no disc edema postoperatively. Expulsive Hemorrhage. Two expulsive hemorrhages occurred out of365 penetrating keratoplasties (0.550% ). No expulsive hemorrhages occurred in the 14,232 cataract removal and IOL implantation cases. This is a total of0.013% of the 15,404 blocks performed for intraocular surgery. One (0.006%) severe acute intraoperative suprachoroidal hemorrhage (AISH) that did not result in a true expulsive hemorrhage occurred in an 85-year-old female with controlled glaucoma, cataract, and systemic hypertension. During phacoemulsification, a severe AISH occurred followed by rupture of the posterior capsule with dislocation of the nucleus into the vitreous. A suture was used to close the wound and the patient was referred to a retinal specialist. Four days later, under general anesthesia and during a pars plana lensectomy-vitrectomy, a second massive acute suprachoroidal hemorrhage occurred, which led to phthisis bulbi. Central Nervous System. One grand mal seizure (0.006%) occurred in a 65-year-old male with a history of hypertension and arteriosclerosis. He received 6 cc of equalpartsof4% lidocaineand0.75% bupivacaine, with 0.2 cc of hyaluronidase with a 11/z-inch Thornton needle through the skin of the upper lid in the superior-temporal quadrant. No epinephrine was used. Six minutes after the injection, the patient had a grand mal seizure, which was treated with succinylcholine chloride 60 mg intravenously by the anesthesiologist. The patient recovered and surgery was performed under peribulbar anesthesia the following month without incident.

DISCUSSION Ideally, a large, masked, randomized comparative study of peribulbar and retrobulbar blocks should be performed. However, the investigators in this study, who 332

based their technique preference on their experience, literature review, and personal evaluations, were unwilling to perform retrobulbar injections. Therefore, to establish the relative safety of peribulbar and to attempt to make some comparison to retrobulbar anesthesia, we elected to correlate the results of this prospective peribulbar study with those of previously published series of retrobulbar anesthesia. There are many problems inherent in this comparison technique; there are a number of reports but few studies that examine efficacy and complication rates of retrobulbar blocks that can be used for comparison. Whitsett and coauthors37 performed a prospective, randomized, double-masked study comparing 50 retrobulbar and 50 one-injection peri bulbar blocks measured by subjective determination of lid akinesia and globe anesthesia and akinesia. Both groups achieved excellent anesthesia and akinesia. Murdoch 38 prospectively compared 50 retrobulbar blocks with 50 peribulbar blocks performed with a 11/4-inch needle. The degree of orbicularis paralysis and degree of ocular akinesia were greater in the peribulbar group. In addition, the subjective evaluation of pain upon injection and the complication rate for retrobulbar hemorrhage and intraoperative posterior pressure were less in the peribulbar group. Weiss and Deichman 36 prospectively compared 40 retrobulbar blocks with 39 peribulbar blocks and found no significant difference in surgeon assessment of akinesia or anesthesia between the two groups. These excellent pilot studies indicate that peribulbar anesthesia is as effective as retrobulbar anesthesia with respect to anesthesia and akinesia. A large, randomized, multicenter comparison study evaluating peribulbar and retrobulbar blocks is needed so that the efficacy and the safety of the two procedures can be directly compared.

Efficacy

A block's effectiveness can be estimated by tabulating the percentage of supplemental blocks required and by subjectively determining the degree of motility in various positions of gaze, as was done by Whitsett and coauthors37 and Murdoch 38 and in the present study. Our mean reinjection rate was 7.92% for the two injection centers and 3.50% for the centers using one injection. This ranged between 1.00% and 10.99% and demonstrates an 89% to 99% efficacy rate as measured by reinjection. Based on the subjective assessment of the degree of akinesia data collected by the eight centers (Table 5), approximately 95% of patients achieved 95% or greater akinesia. Whitsett and coauthors37 reported an 8% reinjection rate for retrobulbar blocks and a 12% reinjection rate while learning the peribulbar technique. In 2,684 consecutive cases, Arnold47 noted only a 1.2% supplemental block rate using a 23-gauge, l-inch sharp needle and a single-injection peribulbar technique. Shriver and coauthors48 described a reblock rate of 4.4% for peri-

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bulbar injections and 6.8% for retrobulbar injections. The difference, using a chi-square method for statistical analysis, was not significant. The peribulbar injection was by either a one-injection or a two-injection technique using a 22-gauge, l-inch needle for peribulbar anesthesia and a 23-gauge, 13/s-inch Atkinson needle for the retrobulbar injection. Hamilton and coauthors 55 described a 19.8% reinjection rate for a 3 cc to 4 cc retrobulbar injection, a 9% reinjection rate for a 5 cc to 7 cc retrobulbar injection, and a 24% reinjection rate for a dual-injection peribulbar block. Weiss and Deichman, 36 using a 5fs-inch needle and 5 cc of injectate for both the retrobulbar group and the peribulbar group, reinjected 21 % in the retrobulbar group and 28% in the single-injection peribulbar group. Using a 26-gauge, '12-inch insulin needle, Kishore et al. 43 supplemented 10% of peribulbar blocks in 360 consecutive patients. Schneider and coauthors44 reported only a 4% reinjection rate out of 148 peri bulbar blocks using a 24-gauge, l-inch needle. It is clear that neither retrobulbar nor peribulbar blocks result in 100% akinesia in every case. The available reports on the reinjection rates for retrobulbar blocks reveal a 6.8% to 19.8% reinjection rate; the comparable rate for peribulbar blocks is 1.2% to 28.0%. The variability in reinjection rate of different centers for peribulbar anesthesia can be partly explained by needle length and volume of injectate. For example, Weiss and Deichman, 36 who had the highest reinjection rate, also used the shortest needle and the lowest volume of anesthetic.

Safety Perforation. In the present study, the rate of globe

perforation was one in 16,224 cases (0.006%). Neither Shriver and coauthors48 nor Arnold47 reported ocular perforation during peribulbar blocks. Kimble and coauthors49 reported one globe perforation secondary to peribulbar anesthesia in 4,200 consecutive cases (0.024%) receiving injections by a single anesthesiologist. There is no large, prospective retrobulbar study to which these statistics can be compared. However, Shriver and coauthors48 noted no ocular perforations in 407 consecutive retrobulbar injections. Ramsay and Knobloch 12 reported three perforations in 4,000 retrobulbar blocks (0.075%) in eyes having retinal detachment repair. 12 A retrospective study by D.B. Davis II, M.D. (unpublished data, 1992) found a one in 1,280 (0.070%) incidence of globe perforation in cataract surgery with retrobulbar anesthesia. Of note, the incidence of globe perforation in the present study was exceedingly low even though injections were performed by variously trained physicians and certified registered nurse anesthetists. Grizzard et aP 1 reported 12 perforations from retrobulbar and peribulbar injections performed by nonophthalmologists. Four cases were from peribulbar injections. Three of the four peribulbar perforations oc-

curred with blunt needles. Hay and coauthors 14 retrospectively reviewed the charts of 23 patients with needle penetration of the globe; 11 had had peri bulbar injections. Six peribulbar injections were administered in the superonasal quadrant, three in the superotemporal quadrant, and two from the inferotemporal direction. Nine of the 11 perforations occurring with the peribulbar injections in Hay and coauthors' 14 report occurred with sharp needles. Duker et al. 13 retrospectively reviewed the charts of patients with globe perforations from retrobulbar or peribulbar anesthesia seen on the retina service at Wills Eye Hospital over a five-year period. They reported on 20 patients, two of whom had perforations due to peribulbar anesthesia. Yet these retrospective reports of isolated cases are referred cases. Thus, we cannot determine the relative incidence of perforation or the relative risk of sharp versus blunt needles. Information to establish a denominator based on the number of blocks performed or the exact frequency of the use of needle type or injection technique is unavailable. Clearly, globe perforations can and do occur with both blunt and sharp needles and with peribulbar as well as retrobulbar blocks. Systemic. In the present study, there were no cases of cardiac or respiratory depression and no deaths from anesthetic. There was only one central nervous system (CNS) complication (seizure) in 16,224 cases (0.006%), which occurred when a 1112-inch needle was used. The rate of CNS complications for retrobulbar anesthesia reported in the literature ranges from 0.09% to 1.50%. In a retrospective review of 910 retrobulbar injections, Petty and coauthors56 reported cardiovascular collapse in two cases (0.22%), respiratory arrest in two cases, and CNS symptoms in three cases (0.33% ). Nicoll et ai.2 5 reported on 6,000 patients who were given retrobulbar anesthesia with a 25-gauge, 1112-inch needle; 16 (0.27%) developed CNS symptoms, mostly respiratory depression. One in 750 (0.13%) injections caused a life-threatening complication. Rodman and coauthors21 reported respiratory depressive episodes in 1.5% of 200 retrobulbar injections when bupivacaine 0. 75% was used as the sole anesthetic agent. In a study by Wittpenn et al.,2 7 respiratory arrest occurred in one in 1,117 patients (0.09%) who were given 2% lidocaine, and in one in 126 (0.79%) given 4% lidocaine as the injectate during retrobulbar anesthesia. Hamilton and coauthors55 reported a 0.15% incidence of brain stem anesthesia using a sharp 27 -gauge, 1112-inch needle and a retrobulbar technique. There were no cases of brain stem anesthesia in the study's 5, 704 peribulbar blocks. In Arnold's47 prospective study of 2,684 peribulbar blocks using a l-inch needle, no cases of systemic or CNS side effects were noted. In the present study, no CNS complications were reported with the use of shorter needles. We believe that shorter needles prevent the accidental deposition of anesthetic into the optic foramen or into the subarachnoid

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space surrounding the optic nerve. 30 A %-inch to l-inch needle is adequate to achieve akinesia and anesthesia in most cases. Schneider and coauthors44 reported a 96% success rate for peri bulbar blocks done with a 24-gauge, l-inch needle. Weiss and Deichman 36 advocate using a 25-gauge, 5/s-inch needle for peribulbar anesthesia. However, their reinjection rate with the needle was 28%. Kishore et al. 43 reported a 90.2% overall success rate (10% reinjection rate) in peribulbar anesthesia using a 26-gauge, If2-inch insulin needle. A shorter needle is less malleable and is not as easily bent by intraorbital tissue as a longer needle. Katsev and coauthors 57 measured 120 human cadaver orbits to determine orbital depth and the position of orbital structures in relation to the length of retrobulbar needles. Their studies led them to believe that the risk of optic nerve sheath perforation with 1112-inch needles is great enough to warrant the use of the shorter 11/4-inch needles. Orbital Hemorrhage. This study shows a low incidence of significant periocular hemorrhage. Twelve orbital hemorrhages were noted in 16,224 cases (0.072% ). One case required cancellation of surgery and 11 had uneventful surgery. Arnold47 noted a 0.60% rate of peribulbar hemorrhage ( 15 out of 2,684 peri bulbar blocks), none significant enough to cancel surgery. A recent study by Cionni and Osher58 had an overall rate of retrobulbar hemorrhage of 1.7% (60 of 3,529 cases) using retrobulbar anesthesia. Osher successfully completed phacoemulsification surgery in 57 of these 60 eyes after digital massage and/or lateral canthotomy. Our study demonstrated a dramatically low percentage of cancelled cases (0.0063%) resulting from peribulbar or retrobulbar hemorrhage. Brown 7 and Ellis6 estimated an incidence of retrobulbar hemorrhage of 1% to 2% of retrobulbar injections. Some or many of the eyes sustaining retrobulbar hemorrhages after retrobulbar anesthesia could have had cataract surgery after proper ocular compression, lateral canthotomy, or both, as reported by Cionni and Osher. 58 Acute Ischemic Optic Neuropathy. It is difficult to compare the incidence of AION in retrobulbar and peribulbar techniques. There has been no reported study addressing this issue with respect to retrobulbar anesthesia per se. However, we believe that the one case of AION in our 16,224 cases represents a reduced AION rate compared to that for retrobulbar anesthesia. Our rate is considerably lower than Davis' incidence of two cases in 1,280 (0.156%) in his retrospective study using retrobulbar anesthesia (unpublished data, 1992). Arnold47 noted one case in 2,684 consecutive peribulbar blocks (0.04%). One can hypothesize placing the anesthetic farther away from the optic nerve and its vessels and the low rate of orbital hemorrhage may reduce the chance of this complication. Expulsive Hemorrhage. Although type of local anesthesia may have no bearing on the incidence of expulsive hemorrhage, it is interesting to note the low number of expulsive hemorrhages in this series. Speaker et al. 59 334

reported an incidence of 16 cases per 10,000 (0.16%) extracapsular cataract extractions (ECCE). In our study, there were no cases of expulsive hemorrhage in 10, 109 phacoemulsification cases (including those with combined glaucoma surgery) or in 4,109 cases of ECCE (including cases combined with glaucoma surgery). Both cases of expulsive hemorrhage occurred during penetrating keratoplasty, an incidence of two cases per 365 keratoplasties (0.55% ). Speaker et al. also reported an incidence of 0.56% expulsive events in penetrating keratoplasty. In the present study, the overall incidence of expulsive hemorrhage was two in 15,404 intraocular surgeries (0.013%). This low number may be the result of the length of post-block compression or type of compression device used and not the anesthetic technique. In this prospective study, the rate of AISH was one in 16,224 (0.006%). This compared to a higher percentage (0.56%) Arnold observed. 47 Again, type of post-block compression device and length of compression time may be significant factors; that is, longer compression may lower the rate of both expulsive hemorrhage and AISH. As Arnold47 noted and our investigation confirmed, a small degree of residual muscle activity in an otherwise totally anesthetic eye does not increase the incidence of intraoperative problems such as positive posterior pressure or expulsive hemorrhage, as it may with retrobulbar anesthesia. Amaurosis. In the present study, the rate of post-block amaurosis was 1.29%, indicating that more than 98% of blocks were indeed peribulbar. Arora and coauthors54 performed serial recordings of distance visual acuity and visually evoked potential (YEP) after peribulbar anesthesia on three patients. They objectively confirmed previous observations that visual acuity remains quite good after peribulbar injection. By using YEP data, they further demonstrated that optic nerve conduction is not significantly affected. We believe that if there is no amaurosis or decrease in optic nerve conduction, optic nerve ischemia and direct trauma is less likely since the optic nerve is not affected by the anesthetic.

Disadvantages of Peribulbar Anesthesia

There are disadvantages to the peribulbar technique. It is a new procedure, requires a larger vol'ume of anesthetic (an unusual concept to surgeons comfortable with smaller retrobulbar volumes), and takes longer to achieve complete globe anesthesia and akinesia. In addition, there have been sporadic reports in the literature of globe perforation, 13·14·49- 51 contralateral amaurosis, 53 and acquired Brown's syndrome. 54 Every new technique has an intrinsic learning curve that can frustrate the surgeon. As with retrobulbar anesthesia, each attempt will not result in total akinesia. When a surgeon is first learning the technique, an incomplete block may occur in 30% to 40% of trials. Whitsett and coauthors37 noted a reinjection rate of 8% for retrobulbar blocks and 12% for peribulbar blocks. Of

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significance, this reinjection rate of 12% occurred while minimized in peribulbar anesthesia because the injecthe surgeon was learning the peribulbar technique; the tion is deposited away from vital structures. The muscles 8% reinjection rate for retrobulbar anesthesia occurred themselves are not engaged and the needle is farther from the globe, optic nerve, dural sheaths, and optic once he had mastered the retrobulbar technique. In peribulbar anesthesia, unlike retrobulbar blocks, foramen than with standard retrobulbar anesthesia, esthe disadvantage of reinjection is offset by the supple- pecially when needles of 11/4 inch or less are used. mental injections being placed away from the globe, Whether directly related to the type of block or to the optic nerve, and apical structures, and the need for only length of post-block compression, the incidence of exsmall amounts (3 cc) of additional injectate. pulsive hemorrhage and intraoperative posterior presThe peri bulbar block requires a larger volume of an- sure is low. esthetic. In retrobulbar anesthesia, typically 3 cc to 4 cc In addition to what appears to be a lower incidence of anesthetic is deposited into the orbital apex behind the of sight- and life-threatening complications in our perglobe, whereas in peribulbar, 4 cc to 10 cc are placed in sonal experience, there seems to be less pain upon inthe extra-muscular space. After the volume offluid is de- jection and no need for an additional seventh nerve posited into the orbit, the lids initially become quite tense. block. In addition, the use of BSS or bicarbonate to We list this as a disadvantage because if not expected, it buffer the initial superficial anesthetic injection, to alarms the surgeon because it mimics a retrobulbar hem- deepen injection further, or both reduces the discomfort orrhage. However, after placement of an ocular com- of the deeper injection. pression device, the area quickly becomes soft, and the Based on the present study and a review of the litersurgeon realizes that no hemorrhage has occurred. ature, peribulbar injection administered with a needle An additional disadvantage of the peribulbar injec- 11/4 inch or shorter with the eye in the primary position tion is that it requires more time to take effect. In a followed by ocular compression is as effective as retrowell-placed retrobulbar injection, adequate anesthesia bulbar and appears to be considerably safer with respect and akinesia may be present within three to five minutes. to ocular, orbital, and systemic complications. We hope With the peribulbar block, anesthesia and akinesia typ- that this study of 16,224 patients stimulates others to ically occur after seven to 12 minutes. However, with perform a randomized, masked, controlled study of retproper planning, this is not a problem and can be ac- robulbar versus peribulbar anesthesia. complished by either the surgeon or an anesthesiologist in a surgical facility or a hospital outpatient department. REFERENCES One should not evaluate ocular motility for at least ten 1. Knapp H. On cocaine and its use in ophthalmic and minutes, thereby avoiding a potentially unnecessary general surgery. Arch Ophthalmol 1884; 13:402-448 reinjection. 2. Feibel RM. Current concepts in retrobulbar anesthesia. 60 Zahl et al. reported on the effects of adjusting the Surv Ophthalmol 1985; 30:102-110 pH of the peribulbar injectate. They concluded that the 3. Gunning KEJ, Collett BJ. Spontaneous retrobulbar haepH-adjusted lidocaine injection reduced the onset time morrhage following anaesthesia. Anaesthesia 1987; 42: for the peribulbar block, bringing it more in line with the 875-876 retrobulbar block. Although we have not found the time 4. Hamilton RC. Brain stem anesthesia following retroof onset of the non-pH-adjusted deeper peribulbar inbulbar blockade. Anesthesiology 1985; 63:688-690 jection to be a problem, adjusting the pH of deeper block 5. Morgan CM, Schatz H, Vine AK, et al. Ocular complications associated with retrobulbar injections. Ophthalmay be helpful for those who are concerned about onsetmology 1988; 95:660-665 time. The additional advantage of pH adjustment is 6. Ellis PP. Retrobulbar injections. 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Ophthalmic Surg 1986; 17:334-337 dle points, the rate of ecchymosis does not appear to be any greater with peribulbar than with retrobulbar injec- 10. Klein ML, Jampol LM, Condon PI, et al. Central retinal artery occlusion without retrobulbar hemorrhage after rettion. Physicians using a conjunctival cul-de-sac aprobulbar anesthesia. Am J Ophthalmol1982; 93:573-577 proach note little or no lid ecchymosis.

SUMMARY Optic nerve, CNS, and systemic complications that are seen in retrobulbar injections appear to be greatly

11. Cowley M, Campochiaro PA, Newman SA, Fogle JA. Retinal vascular occlusion without retrobulbar or optic nerve sheath hemorrhage after retrobulbar injection of lidocaine. Ophthalmic Surg 1988; 19:859-861 12. Ramsay RC, Knobloch WH. Ocular perforation following

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view of technique and complications. Ophthalmol Clin North Am 1990; 3(1):101-110 35. Davis DB II, Mandel MR. Posterior peribulbar anesthesia: an alternative to retrobulbar anesthesia. J Cataract Refract Surg 1986; 12:182-184 36. Weiss JL, Deichman CB. A comparison of retrobulbar and periocular anesthesia for cataract surgery. Arch Ophthalmol 1989; 107:96-98 37. Whitsett JC, Balyeat HD, McClure B. Comparison of one-injection-site peribulbar anesthesia and retrobulbar anesthesia. J Cataract Refract Surg 1990; 16:243-245 38. Murdoch IE. Peribulbar versus retrobulbar anaesthesia. Eye 1990; 4:445-449 39. Wang HS. Peribulbar anesthesia for ophthalmic procedures. J Cataract Refract Surg 1988; 14:441-443 40. Fry RA, Henderson J. Local anaesthesia for eye surgery. The peri-ocular technique (see comments). Comment in: Anaesthesia 1990; 45:695-696; comment in: Anaesthesia 1991; 46:232 41. Bloomberg LB. Administration of periocular anesthesia. J Cataract Refract Surg 1986; 12:677-679 42. Bloomberg LB. Anterior periocular anesthesia: five years experience. J Cataract Refract Surg 1991; 17:508-511 43. Kishore K, Agarwal HC, Sood NN, et al. Evaluation of peribulbar anesthesia in eye camps. Ophthalmic Surg 1990; 21:566-570 44. Schneider M, Faulborn J, Von Hochstetter AH. Posterior peribulbar anesthesia for eye surgery. Eur J Anaesthesiol 1989; 6:425-430 45. Athanikar NS, Agrawal VB. One point low volume peribulbar anaesthesia versus retrobulbar anaesthesia. A prospective clinical trial. Indian J Ophthalmol 1991; 39:4849 46. House PH, Hollands RH, Schulzer M. Choice of anesthetic agents for peribulbar anesthesia. J Cataract Refract Surg 1991; 17:80-83 47. Arnold PN. Prospective study of a single-injection peribulbar technique. J Cataract Refract Surg 1992; 18:157161 48. Shriver PA, Sinha S, Galusha JH. Prospective study of the effectiveness of retrobulbar and peribulbar anesthesia for anterior segment surgery. J Cataract Refract Surg 1992; 18:162-165 49. Kimble JA, Morris RE, Witherspoon CD, Feist RM. Globe perforation from peribulbar injection. Arch Ophthalmol 1987; 105:749 50. Joseph JP, McHugh JDA, Franks WA, Chignell AH. Perforation of the globe-a complication of peribulbar anesthesia. Br J Ophthalmol 1991; 75:504-505 ' 51. Grizzard WS, Kirk NM, Pavan PR, et al. Perforating ocular injuries caused by anesthesia personnel. Ophthalmology 1991; 98:1011-1016 52. Erie JC. Acquired Brown's syndrome after peribulbar anesthesia. Am J Ophthalmol 1990; 109:349-350 53. Vindhya PKC, Sheets JH. Bilateral block with unilateral peribulbar block (letter). Ophthalmic Surgery 1992; 23:69 54. Arora R, Verma L, Kumar A, Kunte R. Peribulbar anesthesia and optic nerve conduction. J Cataract Refract Surg 1991; 17:506-508 55. Hamilton RC, Gimbel HV, Strunin L. Regional anaesthesia for 12,000 cataract extraction and intraocular lens implantation procedures. Can J Anaesth 1988; 35:615623

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56. Petty JM, Davies JM, Strunin L. Retrobulbar block for cataract surgery: retrospective review of 910 patients (abstract). Anaesth Intensive Care 1984; 13:95 57. Katsev DA, Drews RC, Rose BT. An anatomic study of retrobulbar needle path length. Ophthalmology 1989; 96: 1221-1224 58. Cionni RJ, Osher RH. Retrobulbar hemorrhage. Ophthalmology 1991; 98:1153-1155 59. Speaker MG, Guerriero PN, Met JA, et al. A case-control study of risk factors for intraoperative suprachoroidal expulsive hemorrhage. Ophthalmology 1991; 98:202-209 60. Zahl K, Jordan A, McGroarty J, et al. Peribulbar anesthesia: effect of bicarbonate on mixtures of lidocaine, bupivacaine, and hyaluronidase with or without epinephrine. Ophthalmology 1991; 98:239-242 APPENDIX

California; Spencer Thornton, M.D., Baptist Hospital, Nashville, Tennessee; Leroy Bloomberg, M.D., Susan Lampert, C.R.N.A., Dennis Pinkozie, C.R.N.A., Pat White-Hallet, C.R.N.A., Bloomberg Eye Center, Newark, Ohio; Thomas Neuhann, M.D., Rasso Braig, M.D., Tobias Neuhann, M.D., Munich, Germany; Mario Oyarzun, M.D., Edward Luck, M.D.,* Concepcion, Chile; Paul N. Arnold, M.D., Arnold Cataract Clinic, Springfield, Missouri; Dewey Benson, D.O.,t Franklin, Michigan; Robert H. Fier, M.D., Eileen Levin, M.D.,* Henry Venabt, M.D.,* Fier Eye Care & Surgery Center, Stuart, Florida; Charles C. Manger III, M.D., Leon Devlin, M.D.,* Saddleback Eye Center, Laguna Hills, California; Larry Smith, C.R.N.A., Heart of Texas Outpatient Cataract Center, Brownwood, Texas; Albert C. Neumann, M.D., Ambulatory Surgical Center of Central Florida, Deland, Florida; Jack L. Weiss, M.D., Frank Barrack, M.D., San Diego, California

Peribulbar Study Participants David B. Davis II, M.D., Corazon DeGuzman, M.D.,* Mark R. Mandel, M.D., The Davis/Mandel Eye Center, Hayward

*Anesthesiologist, M.D. t Anesthesiologist, D.O.

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