Topical versus retrobulbar anesthesia for combined phacotrabeculectomy: prospective randomized study1

Topical versus retrobulbar anesthesia for combined phacotrabeculectomy Prospective randomized study Iqbal Ike K. Ahmed, MD, Norman A. Zabriskie, MD, Alan S. Crandall, MD, Thomas A. Burns, MD, Stephen C. Alder, PhD, Bhupendra C.K. Patel, MD

Purpose: To compare the safety and efficacy of topical and retrobulbar anesthesia for combined phacotrabeculectomy. Setting: Tertiary-care university hospital ambulatory surgical center. Methods: In this prospective study, 40 consecutive patients having combined phacotrabeculectomy were randomized to receive topical (n ⫽ 20) or retrobulbar (n ⫽ 20) anesthesia. Operating conditions, patient comfort, and surgical outcome were evaluated. Results: There was no significant between-group difference in operating conditions (P ⫽ .56), pain during (P ⫽ .41) or after (P ⫽ .23) surgery, or supplemental anesthesia required (P ⫽ .49). Few patients in either group were bothered by tissue manipulation or the microscope light, although more patients in the topical group were slightly bothered by touch sensation (P ⫽ .05). Chemosis, subconjunctival hemorrhage, and eyelid hematoma were seen almost exclusively in the retrobulbar group (P ⬍ .05). Inadvertent eye movement was present more frequently in the topical group (P ⫽ .04), although this did not pose a problem to the surgeon. Conclusion: Topical anesthesia is a safe and effective alternative to retrobulbar anesthesia for combined phacotrabeculectomy. J Cataract Refract Surg 2002; 28:631– 638 © 2002 ASCRS and ESCRS

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everal methods of local anesthesia for anterior segment surgery are in use. These include retrobulbar,1 peribulbar,2,3 subconjunctival,4 sub-Tenon’s,5 and the application of topical anesthetic drops.6 Topical anesthesia, an increasingly popular technique for cataract surgery, has been shown to be as effective as other methods of anesthesia.7,8 However, little has been reported on the application of topical anesthesia when cataract extraction is combined with glaucoma surgery.9 As with cataract surgery, topical anesthesia for phacotrabeculectomy (combined surgery) is an attractive alternative to injection anesthesia because of the potential for serious complications with the latter method. These include globe perforation, retrobulbar hemorrhage, cen© 2002 ASCRS and ESCRS Published by Elsevier Science Inc.

tral retinal artery occlusion, orbital infection, chronic mydriasis, optic nerve injury, intravascular or intrathecal injection, respiratory depression, apnea, cranial nerve palsy, and death.7,10 –16 More common complications of retrobulbar anesthesia include eyelid and subconjunctival hemorrhage, chemosis, postoperative diplopia, ptosis, nausea, and systemic hypertension.7,17,18 Peribulbar anesthesia, although it reduces the risk of optic nerve injury, can lead to hemorrhage and globe perforation, is time consuming, and requires a greater volume of anesthetic agent than retrobulbar techniques.19,20 To determine whether topical medication alone provides adequate anesthesia for combined surgery, we designed a prospective randomized study comparing 0886-3350/02/$–see front matter PII S0886-3350(01)01249-4

TOPICAL VERSUS RETROBULBAR ANESTHESIA FOR PHACOTRABECULECTOMY

topical and retrobulbar anesthesia for phacotrabeculectomy. Specifically, patient comfort, operating conditions, and the ability to safely perform the operation were studied. A protocol similar to that in 2 previous studies7,21 was used.

Patients and Methods Approval for the study was obtained from the University of Utah Institutional Review Board. Consecutive patients having elective combined surgery without a history of intraocular surgery or procedures involving the conjunctiva were entered in the study. Patients included men and women between 45 and 85 years old and met the American Society of Anesthesiology physical status class 1, 2, or 3. Inclusion criteria for the study included visually significant cataract and uncontrolled glaucoma on maximal medical therapy. Patients with all types of cataracts (eg, posterior subcapsular, nuclear sclerosis, dense brunescent) were included in the study. Those with communication difficulties, monocular status, or taking anticoagulation medications were excluded. Informed consent was obtained. Patients were assigned to a topical anesthesia group (n ⫽ 20) or retrobulbar anesthesia group (n ⫽ 20) by permuted block randomization.

Surgical Technique Preoperatively, baseline vital signs were taken and an intravenous (IV) line with Ringer’s lactate solution was placed. All patients received topical diclofenac sodium 0.1% (Voltaren威), 2 drops every 20 minutes for 2 times; phenylephrine hydrochloride 2.5% (Mydfrin威), 1 drop every 5 minutes for 3 times; and cyclopentolate hydrochloride 1% (Cyclogyl威), 1 drop every 5 minutes for 3 times. The topical group received 2 drops of bupivacaine hydrochloride 0.75% in the preoperative holding area every 5 minutes for 3 times beginning 20 minutes before the procedure. The bupivacaine was nonpreserved with a pH of 5.4. The method of bupivacaine delivery was the same as the standard Accepted for publication October 3, 2001. From the John A. Moran Eye Center (Ahmed, Zabriskie, Crandall, Patel), Department of Anesthesia (Burns), and Department of Family and Preventive Medicine (Alder), University of Utah Health Sciences Center, Salt Lake City, Utah, USA. Supported in part by a grant from Research to Prevent Blindness, Inc., New York, New York, to the Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, USA. None of the authors has a financial or proprietary interest in any material or method mentioned. Reprint requests to Alan S. Crandall, MD, John A. Moran Eye Center, University of Utah Health Sciences Center, 50 North Medical Drive, Salt Lake City, Utah 84132, USA. 632

protocol used at the surgery center at the University of Utah. Six sterile 3 mL syringes were used to draw 1.5 mL of solution from a 10 mL single-dose vial of nonpreserved bupivacaine. The individual syringes required for the entire day were drawn up in the morning. A separate syringe was used to deliver the bupivacaine to each patient. The retrobulbar group received no anesthesia in the preoperative holding area. In the operating room, all patients received continuous nasal prong oxygen 4 L/minute and baseline vital signs were obtained. Before draping, the topical group was given midazolam hydrochloride (Versed威) 0.015 mg/kg and fentanyl citrate 1 ␮g/kg intravenously and an additional 2 drops of bupivacaine 0.75%. Patients in the retrobulbar group were given methohexital sodium 1% (Brevital威) titrated to unconsciousness (approximate dose 0.5 to 1.0 mg/kg) after 2 minutes of preoxygenation with 100% oxygen by face mask. With the patient unconscious, a retrobulbar block was performed with a 23-gauge retrobulbar needle using a solution of 2 mL lidocaine hydrochloride 2%, 2 mL bupivacaine hydrochloride 0.75%, and 150 U hyaluronidase (Wydase威). No ocular compression was performed. Facial or eyelid blocks were not used. Surgery was performed after routine preparation and draping. If breakthrough pain occurred during surgery, supplemental topical bupivacaine 0.75% (2 drops) was administered. If this was not effective, fentanyl (0.5 ␮g/kg) was given intravenously and repeated in 3 minutes if necessary. Supplemental block anesthesia was then administered if required. A 2-site surgical approach was used. One surgeon (A.S.C.) performed all procedures. An open-wire speculum was placed, and no traction sutures were used. Under low microscope lighting, a fornix-based conjunctival flap was fashioned in the superior quadrant initiated by a 5.0 mm limbal peritomy. Light cautery was used for hemostasis. A 4 ⫻ 3 mm trapezoidal scleral flap was then made with a diamond blade, dissecting it into clear cornea with a diamond crescent blade at approximately 70% depth. A Merocel sponge soaked with mitomycin-C (Mutamycin威) 0.2 mg/cc was then placed under the flap and left for 2 minutes followed by copious irrigation with a balanced salt solution. The scope was rotated temporally for cataract extraction. After a 3.2 mm temporal clear corneal incision and side-port paracentesis were created, sodium hyaluronate 1.6% (Amvise威) was used to fill the anterior chamber. No case required pupil stretching or manipulation. A continuous curvilinear capsulorhexis was created and hydrodissection performed. Nuclear disassembly was accomplished by a modified phacochop technique after which the cortex was removed by automated irrigation/aspiration. After the wound was enlarged slightly under viscoelastic material, a foldable intraocular lens was implanted. One radial 10-0 nylon suture was used to close the incision. Acetylcholine 1% (Miochol威) was injected into the anterior chamber to constrict the pupil.

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The scope was rotated superiorly again to complete the trabeculectomy. The anterior chamber was entered under the scleral flap with a diamond keratome. A Crozafon-DeLaange Descemet’s punch was used to make the sclerostomy. A peripheral iridectomy was cut. The scleral flap was then closed with a 10-0 nylon suture at each corner. The viscoelastic material was removed from the anterior chamber through the phacoemulsification wound. Adjustable knots were used to allow titration of the flow under the flap. Once the flow was considered appropriate, the knots were tied off and cut. The conjunctiva was then closed using a 10-0 polyglactin (Vicryl威) suture (Ethicon, D-7329, VAS100-4 needle) in a running horizontal mattress fashion. The conjunctival wound was checked for leakage and if found, the area was oversewn. At the conclusion of the case, a collagen shield soaked in cefazolin and dexamethasone was placed on the eye. After the surgery, patients were taken to the postoperative area, where vital signs were obtained. The patients were kept in the recovery area for a minimum of 30 minutes.

Figure 1. (Ahmed) Descriptive and numerical visual pain analog scale.

rejected for probabilities of a type I error less than 0.05 (P ⬍ .05).

Data Collection After surgery, a constant observer collected patient assessment responses in the recovery area without the presence of the surgeon. Questions were presented to the patients from a standard written form. Each patient was shown a 10-point visual analog pain scale with both written and numeric indices (Figure 1). Patients were asked to grade the level of pain during delivery of anesthesia, during surgery, and postoperatively on separate scales. If the patient was unable to see the scale or read the accompanying text, the scale was described and a verbal response obtained. Patients were also asked to assess the degree to which they were bothered by the sensation of touch and tissue manipulation and by the operating microscope light. The degree to which each bothered the patient was graded as none, a little, or a lot and given a score of 0, 1, or 2, respectively, for statistical purposes. The surgeon also completed an assessment questionnaire immediately after each surgery. Lid squeezing, inadvertent eye movement, and surgical complications were noted. Patient cooperation was graded as excellent, good, or poor. The surgeon also rated the overall surgical conditions on an analog scale, with 10.0 representing excellent, 7.5 good, 5.0 fair, 2.5 poor, and 0 extremely poor. Complications and the need for supplemental anesthesia were recorded.

Statistical Analysis Statistical analyses were performed using SPSS 9.0 for Windows (SPSS Inc.). Comparisons between the topical and retrobulbar groups in the operative conditions, pain during delivery of anesthesia, pain during and after surgery, and patient cooperation were performed using the Wilcoxon (Mann-Whitney) rank sum test. Dichotomous comparisons were performed by Fisher exact tests. The null hypothesis was

Results The operative conditions and complications are shown in Table 1. There was 1 case of posterior capsule rupture with vitreous loss in the topical group and 1 case of capsule rupture without vitreous loss in the retrobulbar group. These complications were not believed to be related to the type of anesthesia used. Overall, patient cooperation assessed by the surgeon was similar in the topical and retrobulbar groups. The surgeon rated patient cooperation excellent in 90% in the topical group and 85% in the retrobulbar group (P ⫽ .64). No patient in either group was rated as having poor cooperation. There were no significant differences between groups in the number of patients requiring supplemental IV or topical anesthesia during surgery. No patient required supplemental periocular anesthesia. Inadvertent eye movement, which was more frequent in the topical group (n ⫽ 5, 25%) than in the retrobulbar group (0) (P ⫽ .04), did not interfere significantly with surgery in any patient. Lid squeezing was noted in 4 patients (20%) in the topical group and 2 (10%) in the retrobulbar group (P ⫽ .66). In the retrobulbar group, chemosis occurred in 15 eyes (75%), eyelid hemorrhage in 10 (50%), and subconjunctival hemorrhage in 5 (25%); chemosis occurred in 1 eye (5%) in the topical group. The difference between groups was significant (P ⬍ .05).

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Table 1. Operative conditions and complications. Number (%) Topical (n ⴝ 20)

Condition/Complication Supplemental periocular anesthesia (injection)

0 (5)

Retrobulbar (n ⴝ 20)

P Value

0

1.00

2 (10)

1.00

Supplemental topical anesthesia

1

Supplemental IV anesthesia (fentanyl)

2 (10)

0

.49

Squeezing of eyelids

4 (20)

2 (10)

.66

Inadvertent eye movement

5 (25)

0

.04*

Retrobulbar hemorrhage

0

0

1.00

Globe perforation

0

0

1.00

Capsule rupture

1

(5)

1

Vitreous loss

1

(5)

0

Successful IOL insertion

20 (100)

(5)

1.00 1.00

20 (100)

1.00

15 (75)

⬍.001*

0

10 (50)

⬍.001*

0

5 (25)

.04*

18 (90)

17 (85)

.64

2 (10)

3 (15)

Chemosis

1

Eyelid hematoma Subconjunctival hemorrhage

(5)

Patient cooperation Excellent Good *Difference between groups statistically significant

The mean score for patient assessment of pain during delivery of the anesthesia was slightly higher in the topical group (Figure 2). The mean visual analog score was 0.45 in the topical group and 0.10 in the retrobulbar group (P ⫽ .08). Fourteen patients (70%) in the topical group and 18 (90%) in the retrobulbar group reported no pain during anesthesia delivery (P ⫽ .56). There were no differences in the patients’ perception of pain during surgery (Figure 3). The mean scores were 0.25 and 0.15 in the topical and retrobulbar group, respectively (P ⫽ .41). Sixteen patients (80%) in the topical group and 18 (90%) in the retrobulbar group reported no pain during surgery (P ⫽ .65). Patients reported similar pain scores in the postoperative period (Figure 4). The mean score for postoperative pain was 0.35 in the topical group and 0.15 in the retrobulbar group (P ⫽ .23). Fifteen patients (75%) in the topical group and 18 (90%) in the retrobulbar group reported no pain during the postoperative period (P ⫽ .60). Figure 5 shows the surgeon’s assessment of the operative conditions. The conditions were excellent in each group with no significant differences between groups 634

(P ⫽ .56). The mean overall analog score was 9.5 in the topical group and 9.6 in the retrobulbar group. Patients reported similar scores for bothersome tissue manipulation and microscope light, with mean scores of 0.1 and 0 (P ⫽ .24) and 0.15 and 0 (P ⫽ .12) in the topical and retrobulbar groups, respectively (Fig-

Figure 2. (Ahmed) Pain scores recorded for the delivery of anesthesia.

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Figure 3. (Ahmed) Pain scores recorded during surgery.

Figure 4. (Ahmed) Pain scores recorded for the postoperative period.

Figure 5. (Ahmed) Operative conditions rated by the surgeon on an analog scale (10 ⫽ excellent; 7.5 ⫽ good; 5 ⫽ fair; 2.5 ⫽ poor; 0 ⫽ extremely poor).

ure 6). However, the mean score for bothersome touch sensation was slightly higher in the topical (0.2) than in the retrobulbar (0) group (P ⫽ .05).

Discussion Topical anesthesia is becoming more popular among cataract surgeons. This move is supported by studies finding no significant difference in patient perception of pain between topical and retrobulbar anesthesia.7,8 Minor and major complications of retrobulbar anesthesia are also precluded by the use of topical anesthesia. Topical anesthesia is less painful to administer without IV sedation or analgesia than retrobulbar or

Figure 6. (Ahmed) Patient perception of tissue manipulation, touch sensation, and microscope light during surgery. Patients were asked to assess whether each bothered them a lot, a little, or not at all.

peribulbar anesthesia, and it does not require that the patient be briefly unconscious for pain-free administration. Additional benefits include rapid visual recovery without the need to patch the eye in the immediate postoperative period and a more cost-effective anesthesia regimen.22 However, there has been little published on the safety and efficacy of topical anesthesia in phacoemulsification combined with trabeculectomy. Specifically in glaucoma procedures, topical anesthesia has important advantages over retrobulbar or peribulbar anesthesia. These include the avoidance of sudden increases in intraocular and orbital pressure after injection anesthesia with a resultant reduction in optic nerve blood flow and potential exacerbation of glauco-

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matous optic neuropathy.23 Furthermore, the risk of retrobulbar hemorrhage, with its potential for marked elevated orbital and intraocular pressure, is eliminated. Also, the risk of subconjunctival hemorrhage, which can hinder surgery and is a potential risk factor for filtration failure, is reduced.24 Alternative anesthesia techniques effective in glaucoma surgery are sub-Tenon’s23,25 and subconjunctival injection.26 Vicary and coauthors27 and Anderson28 report excellent intraoperative pain control and surgical results with subconjunctival anesthesia for combined phacoemulsification and trabeculectomy. However, sub-Tenon’s/subconjunctival anesthesia is still a form of “injection anesthesia,” and chemosis and undesirable subconjunctival hemorrhage extending to more than 1 quadrant are reported to occur in up to 32% of patients.29 Globe perforation has also been reported with this technique.30 Dinsmore9 found that although most patients (92% of 136 cases) having only cataract extraction received adequate pain control with topical anesthesia alone, 2 of 5 patients having a combined procedure and 3 of 5 having a trabeculectomy required additional anesthetic blocks because of pain, most often during conjunctival manipulation and suturing toward the end of surgery. Our study demonstrates that topical anesthesia alone is an effective alternative to retrobulbar anesthesia for phacotrabeculectomy. We found pain control with topical anesthesia as efficacious as retrobulbar anesthesia, with both techniques resulting in little pain during delivery of anesthesia and during or after surgery. Most patients in both anesthesia groups reported no pain at all. No patient in the topical group required supplemental periocular block anesthesia. Topical anesthesia provided excellent operative conditions and patient cooperation in 90% of patients and retrobulbar anesthesia, in 85%. Most patients in both groups were not bothered by tissue manipulation or the microscope light; however, more patients in the topical group reported feeling a touch sensation. Although significantly more patients in the topical group had inadvertent eye movements (25% versus 0%), it did not appreciably interfere with surgery. In fact, the surgeon found that the patients’ ability to follow directions by moving their eye to a desired position during the procedure was helpful in some cases. Al636

though traction sutures were not used in this study, they may be considered if additional control is needed. Our results are not surprising considering that numerous studies show topical anesthesia for cataract surgery to be as efficacious as injection anesthesia without the associated complications.7,8 Furthermore, as experience has increased with the use of topical anesthesia, there have been additional reports of topical anesthesia in complicated cataract extractions and in posterior vitrectomies.31–33 Considerations for topical anesthesia in phacotrabeculectomy are different from those for phacoemulsification alone in many ways. In general, combined glaucoma and phacoemulsification surgery is of longer duration, and the use of cautery, scleral incisions, peripheral iridectomy, and conjunctival manipulation and suturing may cause increased pain. Furthermore, some surgeons may be uncomfortable with the inadvertent eye movements that may occur with topical anesthesia during the filtering portion of the procedure. Strategies to improve patient comfort with topical anesthesia in combined surgery include adequate preoperative counseling, multiple administration of topical anesthesia starting at least 20 minutes preoperatively to allow sufficient tissue penetration, the addition of IV sedation for anxiety and additional pain control, and supplemental topical anesthesia when needed, particularly toward the end of surgery when handling and suturing the conjunctival flap. We now add lidocaine 2% gel before the start of every case, increasing surface contact time of the topical anesthetic agent to provide analgesia throughout surgery and reduce the need for supplemental anesthesia. To minimize confounding variables, intracameral nonpreserved lidocaine 1%, which is a safe and useful adjunct to topical anesthesia in cataract surgery,21 was not used in this study. We now use this regularly in combined procedures and have found it to be helpful during the cataract portion of the procedure.21 Limitations of this study include a small sample size. Thus, nonparametric statistics were performed on the results to determine significance levels. Power analysis (nQuery Advisor 4.0) showed that this study, with a sample size of 20 in each group, had a power of 80% to detect a difference of 0.58 on a 0 to 10 analog pain scale using a Wilcoxon (Mann-Whitney) rank sum test with a 0.05 2-sided significance level. We believe this “mini-

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mum detectable effect” would be able to detect all but the smallest of differences in pain scores and is clinically appropriate. Also, this was not a masked study as it would have been difficult to mask the patient and impossible to mask the surgeon. However, the independent observer collecting patient responses postoperatively was masked to the anesthesia technique. Sedation was used in our study, and this could have affected patient recall when they assessed intraoperative pain levels after surgery. Also, different methods of sedation were used in each group. As sedation had to be used in the retrobulbar group, it was decided that both groups should get some form of sedation. Methohexital was used when administering the retrobulbar anesthesia to bring patients briefly to unconsciousness. Propofol would certainly have been a comparable alternative, although we believed methohexital was an acceptable standard of practice in this setting. After the block, patients remained lightly sedated for the remainder of the procedure, rarely requiring additional sedation or analgesia. With the small doses of midazolam and fentanyl used in the topical group, patients were lightly sedated yet awake and cooperative. Using this formulation for the retrobulbar group would have produced an unacceptably high incidence of pain during placement of the block. However, we believe that after placement of the block in the retrobulbar group, both groups were comparable in levels of consciousness to adequately recall intraoperative pain and discomfort levels postoperatively. Identical sedation protocols have been used in similar well-designed studies.7,8 A final concern is that patient pain levels were recorded postoperatively rather than intraoperatively. Although theoretically intraoperative recording of pain is ideal, we believe some patients are reluctant to “complain” of pain during the surgery, introducing a bias in the result. Conversely, recording intraoperative pain levels postoperatively using an independent observer perhaps provides a more accurate response. Furthermore, other indirect measures of patient comfort recorded by the surgeon in this study, such as patient cooperation and operative conditions, can provide additional information on intraoperative pain levels. Caution must be taken when using topical anesthesia in patients who are deaf or speak a different language than the surgeon. Also, those who are mentally incompetent and very young or anxious patients may not be

good candidates for topical anesthesia. Furthermore, as all patients in this study had primary uneventful phacotrabeculectomy, care is advised when extrapolating these results to patients with scarred conjunctiva or to more difficult cases requiring iris stretching or with intraoperative complications requiring further manipulation. Also, operating times longer than 30 minutes, during which patients may report more pain, may not be applicable. In this study, the surgeon was experienced with topical anesthesia and was able to adjust to this modality for the combined surgery, making minor adjustments in the surgical approach and technique. However, as with any new technique, those not accustomed to topical anesthesia may have a steeper learning curve. In summary, both topical and retrobulbar anesthesia provided optimal operative conditions for the surgeon and excellent pain control for the patient. We found comparable efficacy with both anesthesia techniques. Topical anesthesia is safer than retrobulbar anesthesia for combined phacotrabeculectomy as it eliminates many of the potential problems of injection anesthesia.

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