Ophthalmic regional anaesthesia: A review and update

Nontraditional approaches to sedation for anterior segment surgery: a narrative review

PURPOSE OF REVIEW

Surgical and anesthetic technological advancement have made both cataract and noncataract anterior segment surgery significantly less invasive and time-intensive, facilitating the transition of some of these procedures from the operating room under monitored anesthesia care (MAC) to the office-based setting without MAC. This transition has been aided by the popularization of nonintravenous approaches to achieving patient sedation for these procedures. In this review, we discuss the literature surrounding traditional and nontraditional methods of achieving patient sedation for anterior segment surgery.

RECENT FINDINGS

Our survey of the literature suggests that nonintravenous (IV) approaches to sedation for these procedures may be just as safe, effective, and satisfactory to patients as traditional IV approaches.

SUMMARY

As anterior segment surgery becomes less invasive and less time-intensive, providers considering transitioning their cataract and anterior segment surgery out of the operating room and into the office-based setting without MAC anesthesia should consider the non-IV sedation options outlined in this review to achieve adequate patient sedation and comfort.

Regional Anaesthesia, Contemporary Techniques, and Associated Advancements: A Narrative Review

In particular, the application of regional anaesthesia techniques in existing medicine can be characterized as experiencing regular changes in recent decades. It is useful for obtaining accurate and efficient pain management solutions, from the basic spinal and epidural blocks to the novel ultrasound nerve blocks and constant catheter procedures. These advancements do enhance not only the value of the perioperative period but also the patient's rated optimization as enhancing satisfaction, better precision, and the safety of nerve block placement. The use of ultrasound technology makes it even easier to determine the proper positioning of the needle and to monitor nerve block placement. Moreover, the duration and efficiency of regional anaesthesia are being enhanced by state-of-the-art approaches, which come in the form of liposomal bupivacaine, and better recovery plans and protocols, which shorten recovery time and decrease the number of hospital days. As these methods develop further, more improvements in the safety, efficacy, and applicability of regional anaesthesia in contemporary medicine are anticipated through continued research and innovation.

Improving rat welfare through the development of a peribulbar anaesthesia technique for ophthalmic procedures: A preliminary study

Rats are a commonly used animal model for the study of the pathogenesis and novel treatments of glaucoma, which is induced experimentally using invasive, painful procedures. Peribulbar anaesthesia (PBA) is frequently used in people and domestic animals prior to ophthalmic surgeries to provide excellent perioperative analgesia. Our goal was to develop a PBA technique adapted to rat anatomy, improving the welfare of animals used as a model for glaucoma. Eighteen rat cadavers (n = 36 eyes) were used to establish the optimal needle insertion location. Five injection techniques using 0.1 mL/100 g lidocaine 2% and a contrast agent (1:1 volume ratio) were compared via computed tomography (CT). CT images were scored for injectate distribution at four locations: extraconal, intraconal, around the optic nerve and at the orbital fissure (scale 0-8, where 0 = none and 8 = excellent). Median scores using the dorso-medial-75° (5; range 2-6) and medial-canthus (4.5; range 2-8) injection techniques were not different from the dorso-medial-45° (4; range 3-6) technique and were higher (better distribution) compared with mid-ventral (3; range 2-5) and ventro-lateral (2; range 1-3) techniques. The two superior techniques were used in two experimental rats (n = 4 eyes) to determine the volume of bupivacaine 0.5% necessary to affect corneal touch threshold (CTT) and periocular skin sensitivity (PSS). A volume of 0.05 mL/100 g decreased CTT and PSS for several hours, while a larger volume produced excessively long effects. Dorso-medial-75° or medial-canthus PBA using 0.05 mL/100 g bupivacaine are likely to provide ocular and periocular analgesia in rats, with minor transient adverse effects.

The Effect of Melatonin on Analgesia, Anxiety, and Intraocular Pressure (IOP) in Cataract Surgery Under Topical Anesthesia

PURPOSE

This study investigated the effect of oral melatonin as a premedication before cataract surgery on pain score, anxiety, surgical conditions, and intraocular pressure (IOP) during cataract surgery with phacoemulsification under topical anesthesia.

DESIGN

This randomized, double-blind prospective study was conducted among 120 patients aged 50 to 80.

METHODS

Patients were randomly assigned to receive either sublingual melatonin 3 mg or placebo 60 min before surgery. Verbal anxiety and pain scores, heart rate, systolic and diastolic blood pressure, intraocular pressure, and quality of surgical conditions were recorded. The results were analyzed using SPSS 23 software, and statistical analysis consisted of χ² test and t-test, and a P value less than .05 was considered significant.

FINDINGS

There was a significant difference between the two groups regarding pain after the surgery before being discharged from the recovery room. The mean pain score in the melatonin group was lower than the placebo group in T4 (in the postoperative ward) (P < .05). The anxiety score of patients was lower in the melatonin group in T3 and T4 (during surgery and in the postoperative ward, respectively) (P < .05). IOP was significantly lower in the case group at the end of the surgery after receiving premedication (P = .021).

CONCLUSIONS

This study showed that 3 mg Sublingual melatonin premedication for patients undergoing cataract surgery under topical anesthesia reduced patients' anxiety scores, pain score, and IOP.

A prospective, randomized, triple-blind comparative study of ropivacaine-dexmedetomidine versus ropivacaine alone in peribulbar blocks

Background and Aims

Bupivacaine and lidocaine mixtures are the commonly used local anesthetic drugs for the peribulbar blocks. Because of its safe anesthetic profile, ropivacaine is being investigated as an alternative agent. Several centers have evaluated the effect of the addition of an adjuvant like dexmedetomidine (DMT) to ropivacaine in enhancing the block characteristics. We proposed to evaluate the effect of the addition of DMT to ropivacaine versus a control group not having DMT as adjuvant.

Material and Methods

A prospective, randomized comparative study was conducted on a total of 80 patients attending our hospital for cataract surgeries. Patients were allocated into four groups of 20 each (n = 20) and peribulbar blocks were given 6 mL of 0.75% ropivacaine in group R and 6 mL of 0.75% ropivacaine plus 10 μg, 15 μg, and 20 μg DMT, respectively, in groups RD1, RD2, and RD3.

Results

When DMT was used as an adjunct to ropivacaine, there was a prolongation of the duration of the sensory block.

Conclusion

In peribulbar blocks, 6 mL of ropivacaine 0.75% produces satisfactory block characteristics, and the addition of 10 μg, 15 μg, or 20 μg of DMT as an adjuvant to ropivacaine 0.75% had the effect of significantly prolonging the duration of the sensory block, which is directly proportional to the dose of DMT employed. However, 20 μg of DMT added as an adjuvant to ropivacaine 0.75% appears to be the optimal dose, as this anesthetic drug mixture provides maximum prolongation of the sensory block besides providing satisfactory operating conditions, acceptable sedation levels, and stable hemodynamic parameters.

Comparative study to assess the effect of ropivacaine and a mixture of lidocaine and bupivacaine on intraocular pressure after peribulbar anesthesia for cataract surgery

Purpose

To compare the efficacy of ropivacaine with a mixture of lidocaine and bupivacaine in peribulbar anesthesia for cataract surgery, in terms of post-block intraocular pressure (IOP).

Methods

A one-year comparative study was done to compare two anesthetic solutions in peribulbar anesthesia for cataract surgery, from January 2020 to December 2020 at a tertiary health care hospital. Two hundred patients (40-70 years of age) planned for small-incision cataract surgery with posterior chamber intraocular lens (IOL) implantation under peribulbar anesthesia were included in the study. A single-site inferotemporal injection was given till a total eyelid drop was observed. The IOP was measured at four time-points: before block (control), 1-, 5-, and 15-minute post-block with a tonometer.

Results

The 1-minute post-block mean IOP in both the groups was higher than the baseline levels. This reflected raised intraorbital pressure secondary to peribulbar injection of local anesthetic. However, the rise in 1-minute post-block IOP was significantly less in the ropivacaine group. The 5- and 15-min post-block mean IOP values in the ropivacaine group were significantly lower than the corresponding values of the lidocaine-bupivacaine group and baseline (control) ropivacaine values.

Conclusion

The results of this study support that ropivacaine as a local anesthetic drug for peribulbar block for small-incision cataract surgery can be a suitable alternative to the lidocaine-bupivacaine combination. Studies involving a larger sample size are required to consider ropivacaine as a superior drug to the lidocaine-bupivacaine combination.

Local anaesthesia as a standard of care for penetrating keratoplasty?

BACKGROUND/OBJECTIVES

To determine preferences in the use of local anaesthesia (LA) versus general anaesthesia (GA) for penetrating keratoplasty (PK), and to examine the safety of LA for PK.

SUBJECTS/METHODS

A retrospective analysis of PKs performed at an ophthalmology department in Canada from 01/01/2008 to 01/01/2020 was conducted to investigate rate of major complications. A questionnaire was also sent out to cornea specialists in the United Kingdom (UK) and Canada to determine trends in anaesthesia use for PK. Data on anaesthesia use in keratoplasty data was also obtained from the National Health Service Blood and Tissue (NHSBT) register.

RESULTS

The retrospective study found that 2143 PKs were performed under LA by 4 surgeons. The following complications were revealed: 1 acute anxiety attack with tachycardia, 3 extraocular myotoxicity cases requiring squint surgery, 1 expulsive suprachoroidal haemorrhage and 1 retrobulbar haemorrhage. The survey revealed 92% of cornea specialists in Canada preferred LA to GA. In the UK, 4.5% of specialists preferred LA, with most preferring GA due to suprachoroidal haemorrhage risk. NHSBT data revealed that 86.6% of 6181 PKs performed in UK between 01/04/2015 and 31/03/2020 were done under GA.

CONCLUSIONS

LA is preferred for PK in Canada, in contrast to the UK where GA is preferred. Our retrospective study suggests a low incidence of LA-related complications. We suggest that LA should be considered for most cornea transplant techniques, including optical penetrating keratoplasty. Rising worldwide keratoplasty numbers, ageing populations and risks of pandemics (e.g. COVID-19) give more reason for reduced reliance on GA.

Surgical Advancement of Tenon's Layer During Trabeculectomy Improves Bleb Morphology

Trabeculectomy surgery remains the gold standard incisional glaucoma surgical procedure in many practices, particularly for patients requiring intraocular pressure (IOP) in the low teens or below. However, trabeculectomy surgery is associated with complications including leakage, over filtration, or fibrosis of the surgical bleb. Morphology of the surgical bleb is an important predictor of surgical success defined as long-term IOP reduction with minimal to no complications. There have been many, often subtle, variations in the surgical technique in hopes of improving long-term IOP reduction. However, fewer changes have been implemented specifically to modify bleb morphology. In our surgical practice, we began performing a thorough dissection and advancement of Tenon's layer with incorporation into the conjunctival closure in a 2-layered manner. This technique allowed flow of aqueous to a delineated potential space between sclera and Tenon's layer. Our clinical observations were improved bleb morphology characterized by diffuse, low-lying blebs with nonischemic overlying conjunctiva compared with those performed with a more traditional trabeculectomy technique. Since we incorporated this change into our practice at a defined time, we have a small number of patients in our practice that had a more traditional trabeculectomy technique in the fellow eye. Therefore, in our surgical practice, a small number of patients had trabeculectomy in 1 eye before implementation of this new technique, and then had trabeculectomy in the fellow eye after this technique was adopted, providing opportunity for comparison of bleb morphology with and without Tenon advancement. In series we present two representative, index cases and describe our surgical technique.

Non-Toxic Anesthesia for Cataract Surgery

Background: To study the safety and efficacy provided by a minimal and localized anesthesia in cataract surgery. Methods: Randomized controlled trial. A total of 100 patients undergoing cataract surgery were randomly divided into two groups of 50, which respecitvely received conventional topical anesthesia consisting of preservative-free Oxibuprocaine hydrochloride 0.4% drops or minimal localized anesthesia, administered with a cotton bud soaked in preservative-free Oxibuprocaine hydrochloride 0.4% applied to clear cornea on the access sites for 10 s immediately before surgery. The mean outcome measures were intraoperative pain and the incidence of postoperative ocular discomfort. Results: All patients tolerated well the procedure, giving patin scores between 1–3. Fifteen patients (30%) of group 1 and ten of group 2 (25%) required supplemental anesthesia. No intraoperative complications were recorded. No eyes had epithelial defects at the end of the surgery or at postoperative check-ups. Conclusions: Minimal anesthesia in cataract surgery resulted quick, safe and non-invasive.

A prospective comparison of the efficacy of 0.5% bupivacaine vs 0.75% ropivacaine in peribulbar anesthesia for vitreoretinal surgery

Purpose:

To date, there is no information on the comparison of the effect of 0.5% bupivacaine with 0.75% ropivacaine solution for vitreoretinal surgery. The aim of the study was to compare the efficacy of 0.5% bupivacaine with 0.75% ropivacaine in peribulbar anesthesia for vitreoretinal surgery. This was a prospective randomized double-blinded observational study in a hospital setting. Sixty patients planned for vitreoretinal surgery were randomized into two groups based on the peribulbar injection administered either with 0.5% bupivacaine or 0.75% ropivacaine solution, as Group B (n = 30) and Group R (n = 30), respectively. Time of onset of analgesia, akinesia, and the need for supplemental anesthesia were noted. Student's t-test or Mann-Whitney U test were used for comparing continuous variables and Chi-square or a Fischer exact test were used as appropriate for comparing two proportions.

Results:

The patients in Group R showed an earlier onset of both, analgesia (1.97 min vs. 2.10 min, P = 0.002) and akinesia (2.77 min vs. 4.20 min, P < 0.001) compared with the patients in Group B. The efficacy of the block attained was Grade 5 (adequate anesthesia and akinesia without supplementation) in about 97% of the patients in Group R while only 90% in Group B. However, the differences between the groups for the efficacy of the block were not statistically significant (P = 0.301) neither for Grades 5 nor for Grade 4 and 3 (P = 1.00 for both). The onset of postoperative pain was similar for both groups (P = 1.00).

Conclusion:

We concluded that 0.75% ropivacaine is a better choice of local anesthetic solution for patients undergoing primary vitreoretinal surgery compared with 0.5% bupivacaine.

Lacrimal dilator-facilitated incisionless vs. standard sub-Tenon's block: a randomized, prospective and non-inferiority comparative study

BACKGROUND/OBJECTIVES

Standard sub-Tenon's block (STB) involves incision (dissection) of conjunctiva and Tenon's capsule with the help of blunt scissors and forceps, insertion of a blunt sub-Tenon's cannula under the Tenon's capsule and injection of local anaesthetic agent. STB is frequently associated with minor complications such as chemosis and postoperative subconjunctival haemorrhage but rare sight and life-threatening complications. To reduce these minor complications, several variations of incisionless STB have been described however, there are no comparative data. One such incisionless STB involves the use of lacrimal dilator which is easily available in the operating theatre. We compared incisionless lacrimal dilator-facilitated with the standard STB for effectiveness, chemosis, and postoperative subconjunctival haemorrhage.

SUBJECTS/METHODS

After obtaining ethical approval, patients scheduled to undergo elective phacoemulsification cataract surgery were enroled to receive incisionless lacrimal dilator-facilitated STB (Group LD) or a standard STB using Wescott scissors and blunt forceps (Group WS). All patients received 3 mL 2% lidocaine without any adjuvant. No sedation was administered. Demographics of the patients, duration of the procedure, analgesia, akinesia, duration of the procedure intraoperative chemosis, and postoperative subconjunctival haemorrhage were compared.

RESULTS

Both groups were comparable for demographic data, duration of the procedure, analgesia, and akinesia (p > 0.05). The severity of chemosis and postoperative subconjunctival haemorrhage were significantly lower in Group LD (n = 32) in comparison to Group WS (n = 31) (p < 0.001).

CONCLUSIONS

Incisionless lacrimal dilator-facilitated STB decreases intraoperative chemosis and postoperative conjunctival haemorrhage in comparison to standard STB. Analgesia and akinesia are comparable in both techniques.

Potentially blinding adverse drug reaction to peribulbar lignocaine anesthesia: A rare case report

Peribulbar lignocaine anesthesia is commonly used in ophthalmic surgeries. It rarely causes any severe allergic reaction. A 63-year-old male presented with complicated pseudophakia. He underwent successful vitrectomy under local anesthesia. He later presented with acute-onset proptosis, orbital swelling, and extraocular movement restriction. He was afebrile with normal blood workup and radiological investigations and gave a similar past history. The patient was treated successfully with intravenous medications but two months later developed optic atrophy. An adverse reaction to lignocaine appears to be the most probable cause. Early detection and prompt management of this condition may avert a potentially grave visual outcome. Literature review shows that this case is one of its kinds to report this potentially blinding complication of peribulbar lignocaine anesthesia.

A New Two-Step Anesthesia for 23- or 25-Gauge Vitrectomy Surgery: A Prospective, Randomized Clinical Trial

OBJECTIVE

To investigate the safety and efficacy of topical anesthesia combined with subconjunctival anesthesia (termed two-step anesthesia) for 23- or 25-gauge pars plana vitrectomy or other posterior segment surgery.

METHODS

Patients (n = 90) requiring 23-/25-gauge vitrectomy or other posterior segment surgery were randomized into 3 groups. Group 1 received peribulbar anesthesia, group 2 received retrobulbar anesthesia and group 3 received two-step anesthesia. A 5-point visual analog pain scale (VAPS) was used to measure self-report of patient pain. Complications were recorded for subsequent analysis.

RESULTS

VAPS scores for overall intraoperative pain ranged from 0 to 3 (1.07 ± 1.07) in group 1, from 0 to 2 (0.69 ± 0.93) in group 2 and from 0 to 3 (1.06 ± 0.98) in group 3. Assessment of surgeon discomfort score ranged from 0 to 2 (0.31 ± 0.66) in group 1, from 0 to 3 (0.38 ± 0.82) in group 2 and from 0 to 2 (0.47 ± 0.62) in group 3. Both scores reveal no significant difference among the 3 groups. While there were no complications noted in group 1, there was an ocular perforation in group 2. Additionally, there were no complications in group 3 related to the anesthetic technique.

CONCLUSIONS

Results suggest that two-step anesthesia is a safe and effective anesthetic approach for selected patients undergoing 23- or 25-gauge pars plana vitrectomy or other posterior segment surgeries. It may offer a viable alternative to peribulbar anesthesia and retrobulbar anesthesia for carefully selected 23- or 25-gauge cannular-access ocular surgeries.

Retrospective analysis of complications associated with retrobulbar bupivacaine in dogs undergoing enucleation surgery

OBJECTIVE

To investigate complications associated with, and without, bupivacaine retrobulbar local anesthesia in dogs undergoing unilateral enucleation surgery.

STUDY DESIGN

Retrospective, observational study.

ANIMALS

A total of 167 dogs underwent unilateral enucleation surgery via a transpalpebral approach.

METHODS

Records from 167 dogs that underwent unilateral enucleation surgery that did (RB) or did not (NB) include retrobulbar bupivacaine anesthesia were reviewed, including anesthetic record, daily physical examination records, surgery report, patient discharge report and patient notes within 14 days of the surgery. Specific complications and severity were compared between RB and NB using the Wilcoxon rank-sum test. A 'complication burden' (0-5) comprising five prespecified complications was assigned and tested using rank-sum procedures. Statistical significance was set to 0.05.

RESULTS

Group RB included 97 dogs and group NB 70 dogs. Dogs in NB had a 17.0 percentage points (points) greater risk for a postoperative recovery complication (38.6% versus 21.6%; 95% confidence interval: 3.0-30.6 points; p = 0.017). There was inconclusive evidence that dogs in group RB had a lower risk of requiring perioperative anticholinergic administration (12.4% versus 22.9%; 10.5 points; p = 0.073). Other complications were similar between groups RB and NB with risks that differed by <10 points. The risk of hemorrhage was similar between groups RB (22.7%) and NB (20.0%) with no significant difference in the level of severity (p = 0.664).

CONCLUSIONS AND CLINICAL RELEVANCE

In this retrospective study, the use of retrobulbar bupivacaine for enucleation surgery in dogs was not associated with an increased risk of major or minor complications.

Correlation between sub-Tenon's anesthesia and transient amaurosis during ophthalmic surgery

PURPOSE

To verify the correlation between sub-Tenon's anesthesia and intraoperative visual loss in ophthalmic surgery.

METHODS

Sixty-four patients underwent phacoemulsification combined pars plana vitrectomy under sub-Tenon's anesthesia. Participants were investigated about their light perception at several time points: before anesthesia, immediately after anesthesia, 10 min after anesthesia without any surgical intervention or microscope illumination, and after the whole surgery. Intraoperative amaurosis was determined as that a patient could not see any light from their operative eye. The incidence rate of amaurosis at different time points and among different anesthetists was analyzed.

RESULTS

The rate of intraoperative amaurosis was 0%, 1.56%, 48.44%, and 95.31% at several time points, respectively: before anesthesia, immediately after anesthesia, 10 min after anesthesia without any surgical intervention or microscope light exposure during the interval, and immediately after the whole surgery, presenting a significantly time-dependent increase (P < 0.01). There was no correlation between the amaurosis and different diseases and anesthesiologists. The amaurosis was transient, and all operative eyes could perceive light on the first postoperative day.

CONCLUSIONS

Sub-Tenon's anesthesia contributes to the intraoperative amaurosis during operation. Temporary interruption of optic nerve conduction by the anesthetic could be a credible explanation. The amaurosis is transient and reversible, requires no additional treatment, and should not be considered as a surgical complication.

Comparison of peribulbar block and general anaesthesia in mechanical vitrectomy: a prospective observational study

INTRODUCTION

Vitrectomy surgery is a common procedure for the treatment of several types of ophthalmologic conditions. It can be performed under regional anaesthesia with peribulbar block (PB) or general anaesthesia (GA). There are no evidence-based recommendations on the optimal anaesthesia strategy for this procedure. The aim of this study was to compare the advantages of PB and GA for vitrectomy surgery.

MATERIALS AND METHODS

A prospective observational study was conducted on adults submitted for mechanical vitrectomy between January 2017 and December 2017. Demographic and perioperative data were collected, namely ASA physical status, median arterial pressure, heart rate, postoperative opioid consumption, postoperative nausea and vomiting, times of induction, surgery, recovery, and hospital stay and costs considering medication and material needed. Statistical analysis was performed using SPSS v.25, with chi-square, Fisher and Mann-Whitney U tests, according to the type of variables analysed.

RESULTS AND DISCUSSION

We included 179 patients submitted for mechanical vitrectomy: 91 (51%) with PB and 88 (49%) under GA. Patients submitted to PB were older (69.0 vs. 64.5 years, p=.006) and presented with higher ASA physical status (p=.001). For haemodynamic outcomes, patients submitted to PB presented with less variation of median arterial pressure (-3.0 vs. -13.5mmHg, p=.000) and with no significant differences in heart rate (-2.0 vs. -3.0 bpm, p=.825). In the postoperative period, the PB group presented with decreased need of postoperative analgesia (0.0 vs. 5.0, p=.026) and a lower incidence of nausea and vomiting (1.0 vs. 12.0, p=.001). Times related to anaesthesia and surgery were better in PB group, with shorter induction time (10.0 vs. 11.0min, p=.000), surgery time (56.5 vs. 62.0min, p=.001), recovery time (10.0 vs. 75.5min, p=.000), and hospital stay (2.0 vs. 3.0 days, p=.000). When analysing costs, PB was less expensive than GA (4.65 vs. 12.09 euros, p=.021) CONCLUSION: PB is a reliable and safe alternative to GA for patients undergoing mechanical vitrectomy, permitting good anaesthesia and akinesia conditions during surgery, better haemodynamic stability, and less postoperative complications, especially in older patients and those with more comorbidities.

Ropivacaine plus lidocaine versus bupivacaine plus lidocaine for peribulbar block in cataract surgery: A prospective, randomized, double-blind, single-center, comparative clinical study

Background and Aims:

Cataract surgery in ophthalmology is usually done under peribulbar block with a mixture of 0.5% bupivacaine and 2% lidocaine. Several case reports of fatalities associated with bupivacaine has necessitated a search for alternative safe agents. The aim of this study was to compare peribulbar block characteristics using a mixture of 0.5% bupivacaine and 2% lidocaine with a mixture of 0.5% ropivacaine and 2% lidocaine.

Material and Methods:

Eighty patients were allocated to two random groups of 40 each. Patients of groups BL and RL were given 4 ml of 0.5% bupivacaine and 4 ml of 0.5% ropivacaine each in a mixture with 4 ml of 2% lidocaine and 100 IU of hyaluronidase respectively. Block characteristics, hemodynamic variables, adverse drug interactions and other complications were recorded.

Results:

Demographic characteristics were comparable in both the groups. Duration of onset of the block and the side effect profile was comparable in both the groups but the total duration of the block and the time for first rescue analgesia was found to be longer in group BL than in group RL.

Conclusions:

Ropivacaine 0.5% and lidocaine 2% as a 1:1 mixture in a volume of 8 ml with 100 IU of hyaluronidase is as effective as a 1:1 mixture of bupivacaine 0.5% and lidocaine 2% in a volume of 8 ml with 100 IU of hyaluronidase with regards to onset and total duration of the block and side effects and hemodynamic changes.

A Comparison of Retrobulbar Versus Topical Anesthesia in Trabeculectomy and Aqueous Shunt Surgery

PURPOSE

The purpose of this study was to compare the required supplemental anesthesia and postoperative patient pain score in individuals undergoing glaucoma surgery under topical anesthesia (TA) versus retrobulbar anesthesia (RB).

MATERIALS AND METHODS

A retrospective, interventional, comparative cohort study of 261 eyes of 225 patients undergoing glaucoma and combined glaucoma with cataract surgery were included in the study. The main outcome measures were the amount of supplemental, systemic intraoperative anesthesia used and the postoperative pain scale between patients undergoing TA versus RB anesthesia. A secondary analysis was performed between combined glaucoma and cataract surgery versus glaucoma surgery alone.

RESULTS

About 6.2% patients complained of pain after glaucoma surgery (8.1% among TA group and 3.1% among RB group; P=0.049). Overall, pain tended to be mild with a mean score of 0.32 of 10 for TA and 0.08 of 10 for RB (P=0.027). The amount of IV anesthetics used intraoperatively was lower in the RB anesthesia compared with the TA group (midazolam, P=0.042; fentanyl, P<0.001; propofol, P<0.001). In addition, patients undergoing RB anesthesia were less likely to use postoperative pain medication (P<0.001). There was no difference in pain score (P=0.707) or in the amount of IV anesthetics (all P>0.350) between eyes undergoing combined versus glaucoma surgery alone.

CONCLUSIONS

Although supplemental anesthesia and pain scores were statistically increased in the topical group, the prevalence and the severity of pain was low. Therefore, TA is feasible and a reasonable option for glaucoma surgery. Furthermore, this conclusion applies when glaucoma surgery is performed alone or in combination with the other eye surgery.

Comparison of Olive Tipped and Conventional Steven's Cannula for Sub-Tenon Ophthalmic Anesthesia

PURPOSE:

To compare the efficacy of the olive tipped (OT) cannula to the conventional Steven's cannula for sub-Tenon block (STB) before cataract surgery.

METHODS:

This prospective, randomized, double-masked compared STB delivered in cataract surgery patients with an OT cannula or a conventional Steven's cannula (ST). Outcome variables included the akinesia score and lid movement scores at 5 and 10 min. The patient perception of pain during delivery of the STB and surgery were also compared between groups. Surgeon satisfaction with anesthesia was compared between groups. P <0.05 was statistically significant.

RESULTS:

There were sixty patients in each group. The age between groups was not statistically different (P = 0.4). The body mass index was higher in the ST group compared to the OT group (P < 0.001). The akinesia score at 5 and 10 min did not differ between groups (P = 0.07 and P = 0.6, respectively). The patient perception of pain during STB and surgery were similar between groups (P = 0.1 and P = 0.06, respectively). There were six patients with mild chemosis and redness in the OT group and 15 patients in the ST group.

CONCLUSION:

An OT cannula is equally effective as the conventional Steven's cannula for delivering STB anesthesia before cataract surgery.

Anatomy of anterior ethmoidal foramen, medial canthal tendon, and lacrimal fossa for transcutaneous anterior ethmoidal nerve block in Japanese individuals

PURPOSE

To examine the anatomical relationships of the anterior ethmoidal foramen (AEF), medial canthal tendon (MCT), and lacrimal fossa (LF) in Japanese individuals.

METHODS

Thirty-eight orbits from 19 Japanese cadavers (7 men and 12 women; average age at death, 89.3 years) were used in this experimental anatomical study. The AEF, MCT, and superior border of the LF were exposed. The following distances were then measured: 1) from the point at the medial orbital rim directly anterior to the AEF to the superior border of the MCT (AEF-MCT), and 2) from the superior border of the LF to the superior border of the MCT (LF-MCT).

RESULTS

(AEF-MCT) and (LF-MCT) distances were 9.40±1.92 (mean±standard deviation) and 4.21±1.18 mm, respectively. No values of (LF-MCT) exceeded the mean (AEF-MCT) (9.40 mm).

CONCLUSIONS

The transcutaneous anterior ethmoidal nerve block can be reliably performed without injury to the lacrimal sac by inserting a needle approximately 9 mm superior to the superior border of the MCT.

Rocuronium reversed by sugammadex versus mivacurium during high-risk eye surgery: An institutional anaesthetic practice evaluation

Objective

This institutional anaesthetic practice evaluation compared patient safety with respect to residual neuromuscular blockade (NMB) at the time of tracheal extubation in patients undergoing high-risk eye surgery.

Methods

Two muscle relaxation regimens were compared: rocuronium administered via intravenous (i.v.) bolus dosing combined with reversal through sugammadex at end of surgery (group R/S; 17 patients); mivacurium administered via continuous i.v. infusion without antagonization (group M; 22 patients). Train-of-four (TOF) monitoring determined the depth of NMB.

Results

The TOF ratio at the time of tracheal extubation was greater in group R/S (median 1.03) than in group M (median 0.62). Time from end of surgery to tracheal extubation was not significantly different. The surgeons were 100% satisfied with the working conditions provided under both relaxation regimens.

Conclusions

Residual postoperative curarization at the time of extubation was frequently observed in group M, whereas there was complete recovery in group R/S. Reversal of NMB by sugammadex provides an additional safety dimension to patient care and should thus be considered especially for those at risk of airway complications or aspiration, in addition to frail patients.