Ophthalmic regional blocks: management, challenges, and solutions

Historical and practical aspects of macular buckle surgery in the treatment of myopic tractional maculopathy: case series and literature review

BACKGROUND

Uncorrected myopia is a leading cause of blindness globally, with a rising prevalence in recent decades. Pathological myopia, often seen in individuals with increased axial length (AXL), can result in severe structural changes in the posterior pole, including myopic tractional maculopathy (MTM). MTM arises from tractional forces at the vitreoretinal interface, leading to progressive macular retinoschisis, macular holes, and retinal detachment (RD). This study aims to outline preoperative evaluation and surgical indication criteria for MTM, based on the MTM staging system, and to share our Brazilian experience with three cases of macular buckle (MB) surgery, all with over a year of follow-up.

METHODS

We conducted a retrospective analysis of three cases of MTM-associated RD treated with MB surgery, with or without pars plana vitrectomy. Preoperative evaluations included optical coherence tomography (OCT) and ultrasonography (USG) to assess the extent of macular involvement and retinal detachment. Surgical indications were determined based on the MTM staging system. The MB was assembled using customizable and accessible materials. Surgical procedures varied according to the specific needs of each case. An informed consent form regarding the surgical procedure was appropriately obtained for each case. The study was conducted with the proper approval of the institution's ethics committee.

RESULTS

All three cases demonstrated successful retinal attachment during the mean follow-up of eighteen months. In the first case, combined phacoemulsification, vitrectomy, and MB were performed for MTM with macular hole and RD. The second case required MB and vitrectomy after two failed RD surgeries. In the third case, a macular detachment with an internal lamellar hole was treated with MB alone. These cases highlight the efficacy of MB surgery in managing MTM in highly myopic eyes.

CONCLUSIONS

MB surgery is an effective treatment option for MTM-associated RD in highly myopic eyes, providing long-term retinal attachment. Our experience demonstrates that with proper preoperative evaluation and surgical planning, MB can be successfully implemented using accessible materials, offering a viable solution in resource-limited settings. Further studies with larger sample sizes are warranted to validate these findings and refine surgical techniques.

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.

Comparison between Ultrasonographic-Guided Temporal and Coronoid Approaches for Trigeminal Nerve Block in Dogs: A Cadaveric Study

The trigeminal nerve is responsible for innervating the periorbita. Ultrasound-guided trigeminal block is employed in humans for trigeminal neuralgia or periorbital surgery. There are no studies evaluating this block in dogs. This study aims to evaluate and compare two approaches (coronoid and temporal) of the trigeminal nerve block. We hypothesised superior staining with the coronoid approach. Thirteen dog heads were used. After a preliminary anatomical study, two ultrasound-guided injections per head (right and left, coronoid and temporal approach, randomly assigned), with an injectate volume of 0.15 mL cm-1 of cranial length, were performed (iodinated contrast and tissue dye mixture). The ultrasound probe was placed over the temporal region, visualising the pterygopalatine fossa. For the temporal approach, the needle was advanced from the medial aspect of the temporal region in a dorsoventral direction. For the coronoid approach, it was advanced ventral to the zygomatic arch in a lateromedial direction. CT scans and dissections were conducted to assess and compare the position of the needle, the spread of the injectate, and nerve staining. No significant differences were found. Both approaches demonstrated the effective interfascial distribution of the injectate, with some minimal intracranial spread. Although the coronoid approach did not yield superior staining as hypothesised, it presents a viable alternative to the temporal approach. Studies in live animals are warranted to evaluate clinical efficacy and safety.

Comparison of the effect of 2 mL versus 3 mL sub-Tenon xylocaine injection on akinesia and analgesia in cataract patients at the University of Ilorin Teaching Hospital, Nigeria

PURPOSE

Sub-Tenon anesthesia is a form of local anesthetic techniques used in ophthalmic procedures, especially in cataract surgery. Few studies in our environment have reported the effects of sub-Tenon anesthesia on akinesia and analgesia as well as optimum volumes of anesthetic agents that are required for effective analgesia and akinesia. The objective of this study is to determine and compare the level of analgesia and akinesia and the effect of ocular compressions after sub-Tenon injection of 2 mL versus 3 mL of xylocaine among patients booked for cataract surgery in the University of Ilorin Teaching Hospital (UITH).

METHODS

A cross-sectional comparative study among cataract patients booked for surgery in the Department of Ophthalmology at UITH was carried out from March 2017 to August 2017. A total of 200 cataract patients that met the inclusion criteria were recruited into the study over 6 months. Lists of cataract patients booked for surgery formed the sampling frame. Questionnaires were administered to obtain information on sociodemographic, ocular symptoms, and other histories. Visual acuity was checked, and ocular examination was done with a pen-torch, ophthalmoscope, and slit-lamp examination with 78D. Tonometry and optic nerve assessments were done to exclude any patient with preexisting glaucoma or suspicious disc. About 200 patients were randomly allocated into one of two volume groups (Group 1 had 2 mL sub-Tenon xylocaine injection whereas Group 2 had 3 mL); level of analgesia and akinesia was checked 12 min and 15 min, respectively.

RESULTS

The age range was 20-107 years; mean age for Group 1 was 63.8 ± 12.64, whereas the mean age of Group 2 was 64.14 ± 14.14. There was a slight female preponderance given a M:f of 1:1.4 and more than half of the patients presented with right eye (RE) cataract. Levels of analgesia 12 min after sub-Tenon injections in both groups were similar. However, two patients were found to have severe pain in Group 1, and no patients had severe pain in Group 2. The level of akinesia which was assessed 15 min after injection in both groups was found to be significantly better in Group 2.

CONCLUSION

There was a slight female preponderance with about two-third of the total patients being female and the percentage of females who had no pain was more than the male, more than 50% of the patients had RE cataracts. Sub-Tenon anesthesia whether with 2 mL or 3 mL led to a statistically significant rise in intraorbital pressure (IOP); however, with ocular compression, the IOP was found to decrease below the preinjection pressure in both groups. Levels of analgesia were similar in the two groups, whereas akinesia was statistically better in the group that had 3 mL injection.

Ultrasound-guided versus conventional peribulbar anaesthesia in cataract surgery: A randomised controlled study

BACKGROUND

Blind ophthalmic anaesthetic techniques may have serious complications.

AIM

To assess the safety of ultrasound as a guide in ophthalmic blocks.

METHODS

Fifty adult patients undergoing cataract surgery under peribulbar block anaesthesia were randomly assigned to ultrasound-guided and conventional block groups. In the ultrasound-guided block group, a large amount of the standard ultrasound gel was applied to the closed eyelids. The globes were scanned in both sagittal and transverse planes. The patients were asked to look straight ahead with closed eyes without clenching the eyelids. The depth and gain were adjusted before performing the block. The primary outcome was the rate of complications. Secondary outcomes included the volume of injected anaesthetics and surgeon and patients' satisfaction.

RESULTS

The local anaesthetic volume used was not significantly different between the two groups (7.08 ± 1.66 and 6.72 ± 1.97ml). The block onset, time and quality were comparable in both groups. No complications were reported, and there were no significant differences regarding surgeons' or patients' satisfaction with either procedure.

CONCLUSION

The ultrasound-guided local ophthalmic block is as safe as the conventional method. Although its use was not superior to the conventional procedure, direct visualisation with ultrasound may be important to avoid vulnerable structures such as staphylomas.

Evolving Use of Regional versus General Anesthesia for the Surgical Repair of Open Globe Injuries

PURPOSE

The purpose of the current study is to report outcomes with the evolving use of regional anesthesia with monitored anesthesia care (RA-MAC) vs general anesthesia (GA) in the repair of open globe injuries.

DESIGN

Retrospective, consecutive, comparative, nonrandomized clinical study.

METHODS

The study includes 507 eyes of 507 patients with open globe injuries treated with either RA-MAC or GA at a tertiary referral center between 2015 and 2020. There was no predetermined protocol for selection of anesthesia method. However, based on experience and findings of prior research by this group, regional anesthesia with monitored anesthesia care was typically selected initially and changed to general anesthesia if warranted after evaluation of the patient and discussion with the surgeon. The main outcome measure was visual acuity at last follow-up. Results were compared to previously published study groups between 1995 and 2014.

RESULTS

Primary closure of open globe injury was performed under RA-MAC anesthesia in 462 patients (91%) and under GA in 45 patients (9%). Zone 1, 2, and 3 injuries were recorded in 251, 170, and 86 patients, respectively. Zone 1 (96%, 240 of 251 patients) or zone 2 (92%, 156 of 170 patients) (P < .001) were more likely to be repaired under RA-MAC vs zone 3 injuries (76%, 65 of 86 patients). The improvement from presenting visual acuity was similar for the 2 anesthesia groups, 0.52 logMAR and 0.46 logMAR for RA-MAC and GA, respectively (P = .68, CI -0.3 to 0.2). The use of RA-MAC anesthesia for open globe injuries has increased at our institution from 64% in 1995-1999 to 91% in the present study, 2015-2020 (P < .00001).

CONCLUSION

The current study demonstrates that with anesthesiologists experienced in ophthalmic regional anesthesia techniques, and appropriate case selection, RA-MAC can be safely used as an alternative to general anesthesia for open globe repair. Considerations when employing RA-MAC include a patient's ability to cooperate, position, and communicate for the duration of the globe repair.

Orbital Dynamics and Efficacy of Retrobulbar Anesthesia With and Without Hyaluronidase in Vitreoretinal Surgery

Purpose: To compare retrobulbar anesthesia injection (RAI) with hyaluronidase and without hyaluronidase in vitreoretinal surgery using clinical efficacy measures and orbital manometry (OM). Methods: This prospective randomized double-masked study enrolled patients who had surgery using an 8 mL RAI with or without hyaluronidase. Outcome measures were clinical block effectiveness (akinesia, pain scores, need for supplemental anesthetic or sedative medications) and orbital dynamics assessed by OM before and up to 5 minutes after RAI. Results: Twenty-two patients received RAI with hyaluronidase (Group H+), and 25 received RAI without hyaluronidase (Group H-). Baseline characteristics were well matched. No differences in clinical efficacy were found. OM showed no difference in preinjection orbital tension (4 ± 2 mm Hg in both groups) or calculated orbital compliance (0.6 ± 0.3 mL/mm Hg, Group H+; 0.5 ± 0.2 mL/mm Hg, Group H-) (P = .13). After RAI, the peak orbital tension was 23 ± 15 mm Hg in Group H+ and 24 ± 9 mm Hg in Group H- (P = .67); it declined more rapidly in Group H+. Orbital tension at 5 minutes was 6 ± 3 mm Hg in Group H+ and 11 ± 5 mm Hg in Group H- (P = .0008). Conclusions: OM showed faster resolution of post-RAI orbital tension elevation with hyaluronidase; however, there were no clinically evident differences between groups. Thus, 8 mL RAI with or without hyaluronidase is safe and can achieve excellent clinical results. Our data do not support the routine use of hyaluronidase with RAI.

Anesthetic Approach in Ambulatory Vitrectomy: Peribulbar Block vs. Balanced General Anesthesia

Background

Vitrectomy is one of the most common outpatient ophthalmic surgeries. The anesthetic technique used in outpatient surgery should contribute to a faster functional recovery, better pain control, and fewer complications. The aim of this study was to compare peribulbar block and balanced general anesthesia, in patients undergoing outpatient vitrectomy.

Methods

A prospective cohort study was carried out, including adult patients undergoing ambulatory vitrectomy, between January and February 2018. Peribulbar block or balanced general anesthesia was the independent variable analyzed. Clinical and perioperative variables were evaluated, namely, postoperative pain, nausea, and vomiting in the postoperative period, intraoperative hypotension, patient satisfaction with the anesthetic technique, time to oral diet introduction and to hospital discharge, operating room occupancy time, and pharmacological costs. SPSS^® 27 was used for statistical analyses.

Results

Twenty-one patients were evaluated, 11 of whom underwent peribulbar block and 10 underwent balanced general anesthesia. Patients undergoing peribulbar block did not experience postoperative pain when compared to patients undergoing balanced general anesthesia (p=0.001). Intraoperative hypotension occurred in 18.2% of patients undergoing peribulbar block and in 70% of those undergoing balanced general anesthesia (p=0.03). Time to oral diet introduction (<1 hour vs. > 2 hours; p < 0.05), operating room occupancy time (70 vs. 90 minutes; p=0.027), time to hospital discharge (17 vs. 22.5 hours; p=0.004), and pharmacological costs (4.65 vs. 12.09 euros; p < 0.05) were lower in patients undergoing peribulbar block versus balanced general.

Conclusions

Peribulbar block seems to meet the criteria of an ideal anesthetic technique in outpatient vitrectomy surgery.

Comparing Blind and Ultrasound-Guided Retrobulbar Nerve Blocks in Equine Cadavers: The Training Effect

Simple Summary

Standing ophthalmic surgeries have become more and more common in horses. For these standing surgeries, the blind retrobulbar block is often used for anesthesia and akinesia of the eye. However, placing a retrobulbar block using this blind technique can lead to complications, for example, penetration of the globe, nerve injury or chemosis due to spreading of the local anesthetic in the region of the globe. For this reason, it might be better to perform the retrobulbar block using guidance by ultrasound. Ultrasound-guided retrobulbar block has only been described twice in the literature using equine cadavers. Comparison of the ultrasound-guided peribulbar technique to the blind technique has only been carried out once. Furthermore, the learning curve of ultrasound-guided retrobulbar nerve block placement has not been evaluated. Our study aimed to compare the blind and ultrasound-guided approaches to retrobulbar block placement in horses and to evaluate the success and complication rates, analyzing the effect of training on ultrasound guidance. A trend towards a significant improvement in accuracy was seen for ultrasound guidance, and larger scale follow-up studies might show a significant training effect on the use of ultrasound in retrobulbar nerve block placement and that the use of ultrasound guidance could be promising.

Abstract

In standing ophthalmic surgery in horses, a retrobulbar nerve block (RNB) is often placed blindly for anesthesia and akinesia. The ultrasound (US)-guided RNB may have fewer complications, but the two techniques have only been compared once in equine cadavers. This study compares the techniques for success and complication rates and analyzes the effect of training on US guidance. Twenty-two equine cadavers were divided into three groups: blind RNBs were performed bilaterally in eight cadavers, US-guided RNBs were performed bilaterally in seven cadavers, and after US-guided training, blind RNBs were performed bilaterally in seven cadavers. All RNBs were performed by the same two inexperienced operators, and a combination of contrast medium (CM; 1.25 mL) and methylene blue dye (1.25 mL) were injected (2.5 mL total volume). Needle positioning in the periorbita and the distance of the CM to the optic foramen were assessed using computerized tomography (CT). Dye spreading was evaluated by dissection. In group 1, 37.5% of the injections were in the optimal central position in the periorbita; in group 2, 75% and in group 3, 71.4%. There was no significant difference between the groups regarding needle position (groups 1 and 2 p = 0.056; groups 1 and 3 p = 0.069, groups 2 and 3 p = 0.8). The mean CM distribution distance was not significantly different between all groups. Group 1 had 18.75% intraocular injections versus 0% in group 2 and 7.1% in group 3 (not significant). US guidance showed no significant increases in accuracy nor decreases in complications. However, the effects on accuracy showed a trend towards significant improvement, and larger scale follow-up studies might show significant training effects on US guidance.

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.

Patient and surgeon comfort in vitreoretinal surgery performed with Sub-Tenon's Anaesthesia

Background. Since Stevens first introduced Sub-Tenon's anaesthesia into cataract surgery it has shown itself to be a safe, simple, and efficient technique. The advantages of this type of block are comparable to those of sharp needle anaesthesia and complications are minimal. Several studies have found that the anaesthesia provided by Sub-Tenon's capsule injection is as good as or better for cataract surgery than that achieved by retrobulbar injection, but the efficacy of Sub-Tenon's block in vitreoretinal surgery is less well established. Methods. We performed 50 vitreoretinal procedures; 50 eyes received a Sub-Tenon's injection of a 5 ml mixture (50:50) of lidocaine and ropivacaine, plus 15 IU mL-1 of Hyaluronidase. Results. In 45 cases, only one injection was needed to achieve sufficient anaesthesia and akinesia; in 5 cases a second injection was performed five minutes after the first. Mean surgical time was 45.7 minutes. After surgery, each patient was asked to indicate his value on the VAS pain scale. Mean VAS degree was 2.4. In 7 cases, VAS was > 3 and the pain was successfully managed with the administration of paracetamol in the postoperative period. No light perception was detected at the end of surgery in 33 patients. All cases with 2 injections had no light perception at the end of surgery. Anaesthesia lasted throughout the surgery in all cases. The surgeon performed all surgery comfortably and with no difficulty. Conclusions. According to our experience and to a growing body of evidence, Sub-Tenon's anaesthesia appears to be a safe, simple, versatile, and effective technique and should be considered as a real alternative method of anaesthesia in vitreoretinal surgery.

A computed tomography-based method for the assessment of canine retrobulbar cone volume for ophthalmic anaesthesia

OBJECTIVE

To develop a comprehensive formula for calculating the volume of local anaesthetic solution used for retrobulbar anaesthesia in dogs with different skull morphologies.

STUDY DESIGN

Retrospective cohort imaging study.

ANIMALS

Skull computed tomography (CT) images of 188 dogs of different breeds collected between January 2009 and December 2017.

METHODS

Anatomical integrity of the orbit and adjacent structures, presenting complaint, clinical signs and CT findings were verified to exclude ocular abnormalities. The volume of the retrobulbar cone of 376 eyes was calculated using CT scans of the dogs' skulls. Additional data recorded included morphology of the skull, body weight, sex and size of the dogs, all of which were matched for possible association to the retrobulbar cone volume through univariable and multivariable linear regression models. Results of linear regression models were expressed as estimated beta coefficients with the corresponding 95% confidence intervals (95% CIs).

RESULTS

Using univariate analysis, the retrobulbar cone volume was positively associated with weight and male sex. In addition, brachycephalic and dolichocephalic dogs showed a larger retrobulbar cone volume than mesocephalic dogs, while sex was no longer significantly associated with the retrobulbar cone volume. In multivariate analysis, when considering all variables in the model, weight emerged as the strongest predictor (beta coefficient: 0.062 mL kg^-1, 95% CI: 0.056-0.067 mL kg^-1, p < 0.001).

CONCLUSIONS

and clinical relevance In the veterinary literature, there is no agreement on the precise volume of local anaesthetic solution that should be used to achieve intraconal retrobulbar anaesthesia in dogs. Here we suggest a formula to calculate the retrobulbar cone volume and, accordingly, the injection volume of local anaesthetic solution for effective retrobulbar anaesthesia.

Orbital infarction syndrome following hyaluronic acid filler rhinoplasty

Purpose

Over the last decade, injectable soft tissue fillers have become an essential part of facial plastic surgery practice. We report here a tragic complication of hyaluronic acid filler injection in a young healthy woman, management offered, and the outcome.

Observations

A 32-year-old woman developed unilateral acute blindness, orbital pain, total ophthalmoplegia, and anterior and posterior segment ischemia immediately following hyaluronic acid injection. Urgent measures were taken including hyaluronidase enzyme injection, vigorous messaging, and systemic steroids. Eight weeks later, the extraocular motility has fully recovered; however, the consequences of ischemia on the anterior and posterior ocular segments persisted.

Conclusions and Importance

Describing a major refractory complication following injecting hyaluronic acid dermal filler. Prompt intervention including the use retro or peribulbar injection of hyaluronidase has a little impact when it comes to reversing ocular sequalae. Therefore, injectors should be aware of facial danger zones that could potentially lead to this devastating outcome.

Five Pearls for Long Eyes

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In-plane ultrasound-guided peribulbar block in the dog: an anatomical cadaver study

OBJECTIVE

To describe a novel in-plane ultrasound (U/S)-guided temporal approach to peribulbar block in dogs.

STUDY DESIGN

Prospective experimental cadaver study.

ANIMALS

A group of 10 Beagle cadavers.

METHODS

After describing the U/S anatomy, peribulbar injection was performed bilaterally in 10 thawed Beagle cadavers by two randomly assigned operators. A 5-8 MHz microconvex U/S probe was positioned caudal to the orbital ligament in the longitudinal plane. Using an in-plane technique, methylene blue dye was injected in five dogs (10 eyes total), while methylene blue dye and iohexol contrast mixture (50:50) were injected in the remaining five dogs. Injection volume was 0.2 mL cm^-1 of cranial length. A computed tomography (CT) scan was performed on dogs injected with dye and contrast to identify spread of contrast. Dissection to visualize dye spread in the orbit was performed in all dogs. Injection success was defined as spread of contrast into the peribulbar space. The pattern of distribution of contrast-dye was also assessed. Comparisons between operator and bilateral injections were assessed using a Student t test (p < 0.05). All other data are reported as number (n/N) and percentage (%).

RESULTS

Peribulbar spread was noted in 19/20 injections (95%) on dissection. CT imaging (five dogs) illustrated peribulbar contrast spread in 9/10 injections (90%), with mixed peribulbar/retrobulbar spread for the remaining injection. Contrast was present at the rostral alar foramen in 4/10 (40%) injections, orbital fissure in 5/10 (50%), oval foramen in 1/10 (10%), maxillary nerve in 3/10 (30%) and intracranial in 5/10 (50%). Coverage of the maxillary nerve was noted on 3/20 (15%) injections on dissection. No further dye spread was noted.

CONCLUSIONS AND CLINICAL RELEVANCE

This technique demonstrated peribulbar spread of injectate in 100% of injections for the 10 canine cadavers studied. Further studies are required to evaluate this technique clinically.

Efficacy of ropivacaine versus bupivacaine in preventing peribulbar block failure: A meta-analysis

PURPOSE

Peribulbar block is considered a standard of care in ophthalmological practice due to its easy execution and minor complications. There is a paucity of studies confirming efficacy between ropivacaine and bupivacaine for this specific technique. We evaluated the efficacy of ropivacaine or bupivacaine in preventing total or partial peribulbar block failure in ophthalmic surgeries.

METHODS

Meta-analysis of randomized clinical trials, comparing patients submitted to ophthalmic surgeries under peribulbar anesthesia with ropivacaine and bupivacaine. We searched in different databases for articles published until March, 2018. Data on patients, anesthesia, procedures and akinesia were tabulated. After calculating the chi-square of heterogeneity, we adopted a random-effects model with DerSimonian-Laird test, as well as an odds ratio and a 95% confidence interval.

RESULTS

From the 310 articles identified, 21 studies were selected. The use of ropivacaine was considered a protective factor for ocular akinesia failure in peribulbar block when compared to bupivacaine (OR = 0.53, 95% CI = 0.35-0.81 and p value = 0.003).

CONCLUSIONS

In ophthalmic surgeries, ropivacaine in peribulbar anesthesia is associated with lower rate of block failure when compared to 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.

Regional Anesthesia for Pediatric Ophthalmic Surgery: A Review of the Literature

Ophthalmic pediatric regional anesthesia has been widely described, but infrequently used. This review summarizes the available evidence supporting the use of conduction anesthesia in pediatric ophthalmic surgery. Key anatomic differences in axial length, intraocular pressure, and available orbital space between young children and adults impact conduct of ophthalmic regional anesthesia. The eye is near adult size at birth and completes its growth rapidly while the orbit does not. This results in significantly diminished extraocular orbital volumes for local anesthetic deposition. Needle-based blocks are categorized by relation of the needle to the extraocular muscle cone (ie, intraconal or extraconal) and in the cannula-based block, by description of the potential space deep to the Tenon capsule. In children, blocks are placed after induction of anesthesia by a pediatric anesthesiologist or ophthalmologist, via anatomic landmarks or under ultrasonography. Ocular conduction anesthesia confers several advantages for eye surgery including analgesia, akinesia, ablation of the oculocardiac reflex, and reduction of postoperative nausea and vomiting. Short (16 mm), blunt-tip needles are preferred because of altered globe-to-orbit ratios in children. Soft-tip cannulae of varying length have been demonstrated as safe in sub-Tenon blockade. Ultrasound technology facilitates direct, real-time visualization of needle position and local anesthetic spread and reduces inadvertent intraconal needle placement. The developing eye is vulnerable to thermal and mechanical insults, so ocular-rated transducers are mandated. The adjuvant hyaluronidase improves ocular akinesia, decreases local anesthetic dosage requirements, and improves initial block success; meanwhile, dexmedetomidine increases local anesthetic potency and prolongs duration of analgesia without an increase in adverse events. Intraconal blockade is a relative contraindication in neonates and infants, retinoblastoma surgery, and in the presence of posterior staphylomas and buphthalmos. Specific considerations include pertinent pediatric ophthalmologic topics, block placement in the syndromic child, and potential adverse effects associated with each technique. Recommendations based on our experience at a busy academic ophthalmologic tertiary referral center are provided.

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.

Late hyaluronidase injection in local anesthesia: Morphofunctional evaluation in rat sciatic nerve block

Introduction

Despite the enhancing effects of hyaluronidase (HYAL) over duration of anesthesia, this enzyme could cause adverse effects when injected concomitantly with local anesthetics in dental blocks.

Objective

This study aimed to assess the tissue alterations caused by a local anesthetic protocol consisting of a late HYAL injection and confirm its functional effectiveness.

Materials and Methods

The protocol efficacy was proved by evaluating sensory and motor functions in rats. The sciatic nerve was blocked with 2% lidocaine (LID) with epinephrine (n = 25). Thirty minutes later, 75 TRU/ml HYAL was injected into the same site (experimental group, LID/HYAL). One week later, this protocol was repeated in the contralateral hindlimb, injecting only HYAL's vehicle (control group, LID/vehicle [LID/V]). To observe the integrity of the local tissues, histological specimens were obtained 1, 24, 48, and 72 h after treatment with LID/HYAL or LID/V (n = 16 each) and stained with hematoxylin/eosin and picrosirius red.

Results

Local inflammation was similar in both groups. The integrity of the nerve fibers was preserved, in spite of some inflammation-associated injuries in the surrounding tissues. The reversible tissue disorganization caused by HYAL, probably facilitated the diffusion of the residual anesthetic to the nerve, resulting in a prolonged anesthetic effect (P < 0.05).

Conclusions

No irreversible morphological alterations are caused by the administration of HYAL prior the end of the LID-induced block. Moreover, this protocol prolongs LID's anesthetic effect.

Preventing Adverse Events in Cataract Surgery: Recommendations From a Massachusetts Expert Panel

Massachusetts health care facilities reported a series of cataract surgery-related adverse events (AEs) to the state in recent years, including 5 globe perforations during eye blocks performed by 1 anesthesiologist in a single day. The Betsy Lehman Center for Patient Safety, a nonregulatory Massachusetts state agency, responded by convening an expert panel of frontline providers, patient safety experts, and patients to recommend strategies for mitigating patient harm during cataract surgery. The purpose of this article is to identify contributing factors to the cataract surgery AEs reported in Massachusetts and present the panel's recommended strategies to prevent them. Data from state-mandated serious reportable event reports were supplemented by online surveys of Massachusetts cataract surgery providers and semistructured interviews with key stakeholders and frontline staff. The panel identified 2 principal categories of contributing factors to the state's cataract surgery-related AEs: systems failures and choice of anesthesia technique. Systems failures included inadequate safety protocols (48.7% of contributing factors), communication challenges (18.4%), insufficient provider training (17.1%), and lack of standardization (15.8%). Choice of anesthesia technique involved the increased relative risk of needle-based eye blocks. The panel's surveys of Massachusetts cataract surgery providers show wide variation in anesthesia practices. While 45.5% of surgeons and 69.6% of facilities reported increased use of topical anesthesia compared to 10 years earlier, needle-based blocks were still used in 47.0% of cataract surgeries performed by surgeon respondents and 40.9% of those performed at respondent facilities. Using a modified Delphi approach, the panel recommended several strategies to prevent AEs during cataract surgery, including performing a distinct time-out with at least 2 care-team members before block administration; implementing standardized, facility-wide safety protocols, including a uniform site-marking policy; strengthening the credentialing and orientation of new, contracted and locum tenens anesthesia staff; ensuring adequate and documented training in block administration for any provider who is new to a facility, including at least 10 supervised blocks before practicing independently; using the least invasive form of anesthesia appropriate to the patient; and finally, adjusting anesthesia practices, including preferred techniques, as evidence-based best practices evolve. Future research should focus on evaluating the impact of these recommendations on patient outcomes.

Real-time ultrasound-guided retrobulbar block vs blind technique for cataract surgery (pilot study)

Background

Retrobulbar regional eye block aims to ensure eye globe akinesia and anesthesia during ophthalmic surgery, and despite the rarity of occurrence of complications due to the blind needle passage while performing either peribulbar or retrobulbar block, some of them are serious and may be life threatening.

Aim

The aim of this study was to estimate the accuracy and safety of real-time ultrasound-guided retrobulbar regional anesthesia in comparison with the blind technique for cataract surgery.

Design

This was a prospective randomized controlled trial.

Methodology

A total of 30 patients who met the inclusion criteria were registered in our research and were divided into two groups: 15 patients received real-time ultrasound-guided retrobulbar block compared to 15 patients who received the block using the blind technique.

Results

One patient out of the 30 was excluded from the analysis, and no statistically significant differences were observed between the two groups regarding the onset of akinesia, numeric pain rating scores, rate of complications, and degree of patient and physician satisfaction.

Conclusion

There were no statistically significant difference between real-time ultrasound-guided and blind retrobulbar regional eye blocks concerning the onset of action, total volume of injected local anesthetic solution, supplemental injection required, pain scores, and degree of patient satisfaction.

Effects of hyaluronidase on ropivacaine or bupivacaine regional anaesthesia of the canine pelvic limb

OBJECTIVE

To determine the effect of hyaluronidase on time to onset and offset of anaesthesia in ropivacaine or bupivacaine femoral-ischiatic nerve blocks.

STUDY DESIGN

Blinded randomized crossover trial.

ANIMALS

Eight dogs.

METHODS

Each dog underwent four treatments separated into two blocks - initially, the ropivacaine treatment block: RS (ropivacaine 0.5% plus saline 0.9%) and RH (ropivacaine 0.5% plus hyaluronidase 100 IU mL^-1), followed 3 weeks later by the bupivacaine treatment block: BS (bupivacaine 0.5% plus saline) and BH (bupivacaine 0.5% plus hyaluronidase). The local anaesthetics were administered at 0.1 mL kg^-1 per site. Hyaluronidase and saline were administered at 0.02 mL kg^-1 per site. Performance of femoral-ischiatic blocks was aided by a combined ultrasound-electrolocation technique. The mechanical nociceptive threshold was measured, until offset or 360 minutes, using an algometer to ascertain baseline, onset and offset of anaesthesia. Onset and offset of anaesthesia were defined as a 25% increase above and as a return to <25% above baseline nociceptive threshold readings, respectively.

RESULTS

The median (range) onset of anaesthesia for RS and RH was 21 (3-60) and 12 (3-21) minutes, respectively (p = 0.141), and offset was 270 (90-360) and 180 (30-300) minutes, respectively (p = 0.361). By contrast, the median (range) onset of anaesthesia for BS and BH was 24 (3-60) and 9 (3-27) minutes, respectively (p = 0.394), and offset was 360 (240-360) and 330 (210-360) minutes, respectively (p = 0.456).

CONCLUSION AND CLINICAL RELEVANCE

Hyaluronidase had no effect on the onset and offset times of ropivacaine and bupivacaine femoral-ischiatic nerve blocks in dogs compared with saline. The onset and offset times were highly variable in all treatments. Clinically, the high variability of the onset and offset times of the regional anaesthesia of these local anaesthetic drugs means that clinicians must monitor the animal's response and, if required, provide additional analgesic drugs.

Pain Associated With a Subconjunctival Cefazolin-Lidocaine Mixture in Retinal Surgery:A Randomized Control Trial

BACKGROUND AND OBJECTIVE

The purpose of this randomized, single-masked clinical trial is to explore whether cefazolin mixed with 2% lidocaine can reduce pain.

PATIENTS AND METHODS

Patients naïve to ophthalmic surgery were randomized to subconjunctival injection of either a 0.5 mL cefazolin-balanced salt solution (0.3 mL cefazolin and 0.2 mL balanced salt solution) or 0.5 mL cefazolin-lidocaine solution (0.3 mL cefazolin and 0.2 mL 2% lidocaine) during retinal surgery with a retrobulbar block. Pain scores were obtained at the start of surgery, middle of surgery, before and after cefazolin administration, and postoperatively.

RESULTS

A total of 54 patients were recruited; 44.6% were male, and the mean age was 60.1 years ± 13.5 years. There were no statistically significant differences between the groups' operative characteristics or pain scores at each study time point.

CONCLUSION

In pars plana vitrectomy with or without phacoemulsification and intraocular lens insertion, subconjunctival cefazolin mixed with lidocaine conferred no added analgesic benefit. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:881-886.].

Complication of Peribulbar Block: Brainstem Anaesthesia

Peribulbar block is used to obtain anaesthesia and akinesia of the eye by injecting a local anaesthetic around the musclecone. A patient scheduled for cataract surgery received peribulbar block with 6 mL of 2% lidocaine hydrochloride. Following the injection, confusion, hypotension and dilatation of the contralateral pupil rapidly progressed to loss of consciousness and respiratory arrest. The patient was intubated and mechanically ventilated for 30 min. The patient regained her consciousness, was extubated and transferred to the intensive care unit for further follow-up. Although brainstem anaesthesia because of peribulbar block is very rare, this procedure should be performed with complete monitorisation and resuscitation equipment.

Gamma Knife Radiosurgery for Uveal Metastases: Report of Three Cases and a Review of the Literature

PURPOSE

Uveal metastases are ophthalmologic tumors that have historically been treated by fractionated external beam radiation therapy or invasive brachytherapy. The need for rapid response and less invasive management options led the authors to explore the use of Gamma Knife stereotactic radiosurgery (SRS) for this common problem.

DESIGN

Interventional case series.

METHODS

To prevent eye movement during the procedure, all 3 patients underwent a retrobulbar anesthetic block followed by magnetic resonance imaging to detect the target. All tumors were treated in a single procedure using the 4C or Perfexion Gamma Knife. The tumors received a minimal tumor dose of 14-20 Gy. Two patients also underwent SRS for additional intracranial metastases.

RESULTS

At follow-up, performed between 4 and 15 months after SRS, all 3 patients demonstrated a reduction in uveal tumor volumes. One patient developed decreased visual acuity secondary to radiation retinopathy.

CONCLUSION

In this early experience, SRS was found to be an effective management option for uveal metastases associated with systemic cancer. Patients can be screened and treated effectively early after diagnosis using a joint approach between ophthalmologists and neurosurgeons. Systemic oncologic care can continue without interruption.

Subperiosteal hematoma from peribulbar block during cataract surgery leading to optic nerve compression in a patient with parahemophilia

A 17-year-old male presented with gradual painless diminution of vision since childhood. Slit lamp examination revealed both eyes having congenital cataract. Right eye lens aspiration was performed but was uneventful, and he prepared for left eye surgery after 7 days. Immediately after giving a peribulbar block, a complete akinesia, tight eyelids, and stony hard eyeball was noted. An abaxial proptosis of 7 mm was noted. Lateral canthotomy and inferior cantholysis were done and proptosis reduced to 5 mm. Bleeding time–clotting time was normal. Proptosis worsened to 8 mm the next day. Contrast-enhanced computed tomography scan showed inferolateral subperiosteal hematoma, but drainage could not be performed due to prolonged prothrombin time and activated prothrombin time. Fresh frozen plasma was transfused. Tarsorrhaphy was performed for exposure keratopathy after his coagulation profile became normal. Hematology evaluation after 2 weeks detected factor V deficiency, and was diagnosed as Owren’s disease or parahemophilia.