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Does preservative-free lignocaine 1% for hydrodissection reduce pain during phacoemulsification?2
Does preservative-free lignocaine 1% for hydrodissection reduce pain during phacoemulsification? Jennifer H.Y. Tan, FRCS, Robert L. Burton, FRCOphth ABSTRACT Purpose: To compare preservative-free 1% lignocaine with balanced salt solution (BSS姞) in alleviating pain during hydrodissection in phacoemulsification cataract surgery. Setting: West Norwich Hospital, Norfolk, United Kingdom. Methods: This prospective double-masked trial comprised 68 patients having day-case phacoemulsification cataract surgery. Patients were randomly divided into 2 groups, receiving either BSS or lignocaine 1% solution for hydrodissection during routine uneventful phacoemulsification using topical anesthesia. The level of intraoperative pain was scored on a scale of 0 (no pain) to 10 (severe pain), and the scores between the 2 groups were compared. Results: Of the 68 patients, 33 (49%) received BSS and 35 (51%), lignocaine 1% solution. A pain score greater than 2 was considered clinically significant; 28 patients (85%) in the BSS group and 25 (71%) in the lignocaine 1% group scored 2 or less. The chi-square and Mann–Whitney tests found no significant difference between the BSS and lignocaine 1% groups (P ⫽ .30 and P ⫽ .432, respectively). Conclusion: There was no significant difference in the pain scores in patients who received BSS or lignocaine 1% solution. Thus, we conclude that hydrodissecting with lignocaine 1% solution does not provide added pain relief during phacoemulsification. J Cataract Refract Surg 2000; 26:733–735 © 2000 ASCRS and ESCRS
T
he development of small sutureless incisions through a corneal or limbal approach has made it possible for modern cataract surgery to be performed using topical anesthesia. This relatively uninvasive procedure has resulted in almost immediate visual recovery and thus high patient satisfaction.1–3 A better visual outcome can be achieved with strategic selection of the cataract incision site, overcoming astigmatism that may be present. Unfortunately, topAccepted for publication December 17, 1999. Reprint requests to Miss Jennifer H.Y. Tan, FRCS, Department of Ophthalmology, Leicester Royal Infirmary, Leicester LE1 5WW, United Kingdom. E-mail: jtan㛭[email protected] © 2000 ASCRS and ESCRS Published by Elsevier Science Inc.
ical anesthesia may not suit every patient and a more definitive method of anesthetizing the eye may be required, especially in anxious and uncooperative patients. Several methods of reducing intraoperative pain or discomfort under topical anesthesia have been described. Studies in which preservative-free lidocaine was administered into the anterior chamber after entry and phacoemulsification 1 minute after the intracameral injection report that lidocaine controlled intraoperative discomfort.4 Anterior chamber irrigation of preservative-free lidocaine 1% has been found to be effective in anesthetizing the eye for temporal corneal incision cataract surgery.5 0886-3350/00/$–see front matter PII S0886-3350(00)00311-4
LIGNOCAINE TO REDUCE PAIN DURING PHACOEMULSIFICATION
The use of lidocaine for hydrodissection has been suggested as a way to reduce pain during cataract surgery. It has an added advantage in that there is no extra step during the procedure.
Patients and Methods After it was approved by the ethical committee, a randomized controlled prospective study was performed to compare preservative-free lignocaine 1% and balanced salt solution (BSS威) (placebo) for hydrodissection during phacoemulsification cataract surgery. Informed consent was obtained from patients on a routine day-case list. Exclusion criteria were as follows: previous intraocular surgery, inflammation or injury, a pupil size less than 5.0 mm in diameter when fully dilated, and inability to understand a visual analog pain scale. Thirty minutes before surgery, all patients received phenylephrine 2.5%, cyclopentolate 1%, and diclofenac 0.1%. For topical anesthesia, 3 drops of amethocaine 1% were instilled over a 10 minute period before surgery. The pharmacy department supplied 2 mL syringes containing preservative-free lignocaine or BSS. The contents were represented by serial numbers labeled on the syringes, and this information was known by only the head pharmacist. Randomization was done in the pharmacy department, and the syringes were used serially. Both BSS and preservative-free lignocaine 1% are clear, colorless solutions, making it impossible to differentiate 1 from the other. The contents of the syringes were unknown to operating theater staff, the surgeon, or the patient, keeping the study double masked. All the surgery was performed by 1 surgeon (R.L.B.) and was standardized for each case. A 5.0 mm frown incision with a 2.0 to 3.0 mm scleral pocket was made at 12 o’clock, followed by capsulorhexis and bimanual nucleofractis phacoemulsification. A 5.5 mm intraocular lens was implanted in the capsular bag and the wound left unsutured. A temporal approach was used when the patient had deep-set eyes or to neutralize astigmatic errors. The scrub nurse handed the preloaded syringes containing the lignocaine or BSS on a Rycroft cannula to the surgeon for hydrodissection, separating the nuclear material from the capsular bag. On completion of the surgery, the serial number of the syringe used for that 734
particular patient was documented. During the study, all operative procedures were kept standardized and the same personnel performed all study-related procedures and measurements. Efficacy of treatment was assessed by comparing pain or discomfort levels determined using a scoring system. A wooden board was placed before the patient. On the left of the board was a score of 0, accompanied by a “smiling face.” Numbers increased equidistantly to a score of 10, which appeared on the right side of the board and was accompanied by a “crying face.” A sliding marker indicated the severity of pain the patient experienced. On completion of surgery, patients were taken into another room and given the score board to quantify the amount of pain or discomfort they felt during the operation.
Results Of the 68 patients recruited into the study, the BSS group consisted of 33 (49%) and the lignocaine group, 35 (51%). A pain score greater than 2 on the visual analog scale was considered clinically significant. In the BSS group, 5 (15%) scored greater than 2 and 28 (85%) 2 or less. In the lignocaine group, 10 (29%) scored greater than 2 and 25 (71%) 2 or less. A chi-square test with Yates correction for continuity showed no significant difference between the BSS and lignocaine 1% groups (P ⫽ .30). The difference in proportions of patients with pain scores of 2 or less between the BSS and lignocaine groups was 13% (95% confidence interval, ⫺6 to 33). The Mann–Whitney test of pain scores between the lignocaine and BSS groups was not significant (P ⫽ .432). The 95% confidence interval for the difference (BSS minus lignocaine) between the medians was –1.0 to 0.0.
Discussion There is always a concern when new substances are introduced into the eye. A relative lack of retinal toxicity after full visual recovery after the use of intracameral lidocaine to repair a traumatic corneal graft dehiscence has been reported.6 In vitro exposure to lidocaine hydrochloride 1% is safe to both the human7,8 and rabbit endothelium in the short term.8 However, long-term
J CATARACT REFRACT SURG—VOL 26, MAY 2000
LIGNOCAINE TO REDUCE PAIN DURING PHACOEMULSIFICATION
follow-up studies of endothelial counts and morphological analyses are needed to confirm the lack of toxicity with the use of intracameral local anesthesia. Mobilization of the iris–lens diaphragm is postulated to cause discomfort during phacoemulsification cataract surgery. Significant variations in fluid pressures occur in the eye, especially during (1) hydrodissection, when a pressure difference is unavoidable to achieve the separation of lens matter from the capsular bag, and (2) when the phacoemulsification probe is introduced into the anterior chamber with ongoing irrigation. When a watertight seal is achieved in phacoemulsification, the variation in fluid pressure is great and may cause the patient discomfort or pain. Lidocaine in the anterior chamber reduces pain during cataract surgery but involves an extra surgical step. This study sought to determine whether use of lignocaine during hydrodissection reduces the discomfort of cataract surgery. The discomfort is caused by movements of the lens–iris diaphragm resulting from fluctuations in anterior chamber depth. We had hoped that lignocaine given during hydrodissection would reach the ciliary body or back surface of the iris, where presumably the pain is felt. We found that lignocaine 1% is no better than BSS for hydrodissecting the nucleus from the capsular bag in phacoemulsification. The probable causes of failure are the short time the anesthetic was in the eye and that it remained in the capsular bag rather than reaching the iris/ciliary body. In view of its unknown long-term side effects in intracameral local anesthesia, we do not advocate the use of lignocaine for hydrodissection in phacoemulsification cataract surgery.
References 1. Manners TD, Burton RL. Randomised trial of topical versus sub-Tenon’s local anaesthesia for small-incision cataract surgery. Eye 1996; 10:367–370 2. Maclean H, Burton T, Murray A. Patient comfort during cataract surgery with modified topical and peribulbar anesthesia. J Cataract Refract Surg 1997; 23:277–283 3. Duguid IGM, Claoue´ CMP, Thamby-Rajah Y, et al. Topical anaesthesia for phacoemulsification surgery. Eye 1995; 9:456 – 459 4. Gills JP. Cherchio M, Raanan MG. Unpreserved lidocaine to control discomfort during cataract surgery using topical anesthesia. J Cataract Refract Surg 1997; 23:545– 550 5. Koch PS. Anterior chamber irrigation with unpreserved lidocaine 1% for anesthesia during cataract surgery. J Cataract Refract Surg 1997; 23:551–554 6. Hoffman RS, Fine IH. Transient no light perception visual acuity after intracameral lidocaine injection. J Cataract Refract Surg 1997; 23:957–958 7. Garcia A, Loureiro F, Lima˜o A, et al. Preservative-free lidocaine 1% anterior chamber irrigation as an adjunct to topical anesthesia. J Cataract Refract Surg 1998; 24:403– 406 8. Kim T, Holley GP, Lee JH, et al. The effects of intraocular lidocaine on the corneal endothelium. Ophthalmology 1998; 105:125–130 From the Department of Ophthalmology, West Norwich Hospital, Norwich, United Kingdom. Presented at the annual meeting of the United Kingdom & Ireland Society of Cataract & Refractive Surgeons, Chester, United Kingdom, September 1998. Neither author has a financial interest in any product mentioned. Nicholas Taub provided statistical analysis and Kim Buckenham, assistance.
J CATARACT REFRACT SURG—VOL 26, MAY 2000
735
T
he development of small sutureless incisions through a corneal or limbal approach has made it possible for modern cataract surgery to be performed using topical anesthesia. This relatively uninvasive procedure has resulted in almost immediate visual recovery and thus high patient satisfaction.1–3 A better visual outcome can be achieved with strategic selection of the cataract incision site, overcoming astigmatism that may be present. Unfortunately, topAccepted for publication December 17, 1999. Reprint requests to Miss Jennifer H.Y. Tan, FRCS, Department of Ophthalmology, Leicester Royal Infirmary, Leicester LE1 5WW, United Kingdom. E-mail: jtan㛭[email protected] © 2000 ASCRS and ESCRS Published by Elsevier Science Inc.
ical anesthesia may not suit every patient and a more definitive method of anesthetizing the eye may be required, especially in anxious and uncooperative patients. Several methods of reducing intraoperative pain or discomfort under topical anesthesia have been described. Studies in which preservative-free lidocaine was administered into the anterior chamber after entry and phacoemulsification 1 minute after the intracameral injection report that lidocaine controlled intraoperative discomfort.4 Anterior chamber irrigation of preservative-free lidocaine 1% has been found to be effective in anesthetizing the eye for temporal corneal incision cataract surgery.5 0886-3350/00/$–see front matter PII S0886-3350(00)00311-4
LIGNOCAINE TO REDUCE PAIN DURING PHACOEMULSIFICATION
The use of lidocaine for hydrodissection has been suggested as a way to reduce pain during cataract surgery. It has an added advantage in that there is no extra step during the procedure.
Patients and Methods After it was approved by the ethical committee, a randomized controlled prospective study was performed to compare preservative-free lignocaine 1% and balanced salt solution (BSS威) (placebo) for hydrodissection during phacoemulsification cataract surgery. Informed consent was obtained from patients on a routine day-case list. Exclusion criteria were as follows: previous intraocular surgery, inflammation or injury, a pupil size less than 5.0 mm in diameter when fully dilated, and inability to understand a visual analog pain scale. Thirty minutes before surgery, all patients received phenylephrine 2.5%, cyclopentolate 1%, and diclofenac 0.1%. For topical anesthesia, 3 drops of amethocaine 1% were instilled over a 10 minute period before surgery. The pharmacy department supplied 2 mL syringes containing preservative-free lignocaine or BSS. The contents were represented by serial numbers labeled on the syringes, and this information was known by only the head pharmacist. Randomization was done in the pharmacy department, and the syringes were used serially. Both BSS and preservative-free lignocaine 1% are clear, colorless solutions, making it impossible to differentiate 1 from the other. The contents of the syringes were unknown to operating theater staff, the surgeon, or the patient, keeping the study double masked. All the surgery was performed by 1 surgeon (R.L.B.) and was standardized for each case. A 5.0 mm frown incision with a 2.0 to 3.0 mm scleral pocket was made at 12 o’clock, followed by capsulorhexis and bimanual nucleofractis phacoemulsification. A 5.5 mm intraocular lens was implanted in the capsular bag and the wound left unsutured. A temporal approach was used when the patient had deep-set eyes or to neutralize astigmatic errors. The scrub nurse handed the preloaded syringes containing the lignocaine or BSS on a Rycroft cannula to the surgeon for hydrodissection, separating the nuclear material from the capsular bag. On completion of the surgery, the serial number of the syringe used for that 734
particular patient was documented. During the study, all operative procedures were kept standardized and the same personnel performed all study-related procedures and measurements. Efficacy of treatment was assessed by comparing pain or discomfort levels determined using a scoring system. A wooden board was placed before the patient. On the left of the board was a score of 0, accompanied by a “smiling face.” Numbers increased equidistantly to a score of 10, which appeared on the right side of the board and was accompanied by a “crying face.” A sliding marker indicated the severity of pain the patient experienced. On completion of surgery, patients were taken into another room and given the score board to quantify the amount of pain or discomfort they felt during the operation.
Results Of the 68 patients recruited into the study, the BSS group consisted of 33 (49%) and the lignocaine group, 35 (51%). A pain score greater than 2 on the visual analog scale was considered clinically significant. In the BSS group, 5 (15%) scored greater than 2 and 28 (85%) 2 or less. In the lignocaine group, 10 (29%) scored greater than 2 and 25 (71%) 2 or less. A chi-square test with Yates correction for continuity showed no significant difference between the BSS and lignocaine 1% groups (P ⫽ .30). The difference in proportions of patients with pain scores of 2 or less between the BSS and lignocaine groups was 13% (95% confidence interval, ⫺6 to 33). The Mann–Whitney test of pain scores between the lignocaine and BSS groups was not significant (P ⫽ .432). The 95% confidence interval for the difference (BSS minus lignocaine) between the medians was –1.0 to 0.0.
Discussion There is always a concern when new substances are introduced into the eye. A relative lack of retinal toxicity after full visual recovery after the use of intracameral lidocaine to repair a traumatic corneal graft dehiscence has been reported.6 In vitro exposure to lidocaine hydrochloride 1% is safe to both the human7,8 and rabbit endothelium in the short term.8 However, long-term
J CATARACT REFRACT SURG—VOL 26, MAY 2000
LIGNOCAINE TO REDUCE PAIN DURING PHACOEMULSIFICATION
follow-up studies of endothelial counts and morphological analyses are needed to confirm the lack of toxicity with the use of intracameral local anesthesia. Mobilization of the iris–lens diaphragm is postulated to cause discomfort during phacoemulsification cataract surgery. Significant variations in fluid pressures occur in the eye, especially during (1) hydrodissection, when a pressure difference is unavoidable to achieve the separation of lens matter from the capsular bag, and (2) when the phacoemulsification probe is introduced into the anterior chamber with ongoing irrigation. When a watertight seal is achieved in phacoemulsification, the variation in fluid pressure is great and may cause the patient discomfort or pain. Lidocaine in the anterior chamber reduces pain during cataract surgery but involves an extra surgical step. This study sought to determine whether use of lignocaine during hydrodissection reduces the discomfort of cataract surgery. The discomfort is caused by movements of the lens–iris diaphragm resulting from fluctuations in anterior chamber depth. We had hoped that lignocaine given during hydrodissection would reach the ciliary body or back surface of the iris, where presumably the pain is felt. We found that lignocaine 1% is no better than BSS for hydrodissecting the nucleus from the capsular bag in phacoemulsification. The probable causes of failure are the short time the anesthetic was in the eye and that it remained in the capsular bag rather than reaching the iris/ciliary body. In view of its unknown long-term side effects in intracameral local anesthesia, we do not advocate the use of lignocaine for hydrodissection in phacoemulsification cataract surgery.
References 1. Manners TD, Burton RL. Randomised trial of topical versus sub-Tenon’s local anaesthesia for small-incision cataract surgery. Eye 1996; 10:367–370 2. Maclean H, Burton T, Murray A. Patient comfort during cataract surgery with modified topical and peribulbar anesthesia. J Cataract Refract Surg 1997; 23:277–283 3. Duguid IGM, Claoue´ CMP, Thamby-Rajah Y, et al. Topical anaesthesia for phacoemulsification surgery. Eye 1995; 9:456 – 459 4. Gills JP. Cherchio M, Raanan MG. Unpreserved lidocaine to control discomfort during cataract surgery using topical anesthesia. J Cataract Refract Surg 1997; 23:545– 550 5. Koch PS. Anterior chamber irrigation with unpreserved lidocaine 1% for anesthesia during cataract surgery. J Cataract Refract Surg 1997; 23:551–554 6. Hoffman RS, Fine IH. Transient no light perception visual acuity after intracameral lidocaine injection. J Cataract Refract Surg 1997; 23:957–958 7. Garcia A, Loureiro F, Lima˜o A, et al. Preservative-free lidocaine 1% anterior chamber irrigation as an adjunct to topical anesthesia. J Cataract Refract Surg 1998; 24:403– 406 8. Kim T, Holley GP, Lee JH, et al. The effects of intraocular lidocaine on the corneal endothelium. Ophthalmology 1998; 105:125–130 From the Department of Ophthalmology, West Norwich Hospital, Norwich, United Kingdom. Presented at the annual meeting of the United Kingdom & Ireland Society of Cataract & Refractive Surgeons, Chester, United Kingdom, September 1998. Neither author has a financial interest in any product mentioned. Nicholas Taub provided statistical analysis and Kim Buckenham, assistance.
J CATARACT REFRACT SURG—VOL 26, MAY 2000
735