sub-Tenon's Block Research Articles

Case report: A Unique Case of Brainstem Anesthesia and Contralateral Amaurosis Following a Sub-Tenon Block.

To report and discuss a case of brainstem anesthesia and contralateral amaurosis following a sub-Tenon block. Single surgical case report of a patient who underwent an uncomplicated pars plana vitrectomy for an epiretinal membrane peel in the left eye following a sub-Tenon anesthesia technique. Post-operatively, the patient experienced symptoms of brainstem anesthesia as well as akinesia, a non-reactive pupil, and reduced visual acuity in the contralateral eye which gradually resolved within 24 hours. Imaging was within normal limits and did not reveal any anatomic abnormalities. Despite the use of a blunt-ended cannula in a sub-Tenon block, there is a non-negligible risk of it penetrating surrounding structures such as the optic nerve sheath. This case emphasizes the importance of monitoring for brainstem anesthesia and contralateral eye affections in patients both intra- and post-operatively.

Pars Plana Vitrectomy Without Intravenous Anesthesia: Technique, Safety, and Outcomes.

Introduction: To describe the technique, safety profile, and outcomes of performing pars plana vitrectomy (PPV) without intravenous (IV) anesthesia. Methods: This retrospective single-surgeon study comprised patients who had PPV without IV sedation between September 2018 and April 2022. Patients elected to undergo PPV without sedation or with oral sedation via sublingual triazolam administered 30 minutes preoperatively. Sub-Tenon bupivacaine and lidocaine were administered at the initiation of each case. A circulating nurse monitored patient vitals and electrocardiogram tracings without anesthesiologist support. Adverse events (AEs), visual acuity (VA), supplemental block administration, and reoperation rates were documented. Results: A total of 357 PPVs in 319 patients (mean age 68.75 ± 11.17 years [SD]; range, 36.82-98.57) were performed for surgical indications including vitreous floaters, intraocular lens or cataract surgery complications, retinal detachment, vitreous hemorrhage, and epiretinal membrane. Twenty-three cases were performed without sedation, and 334 were performed with oral sedation. For eyes with a follow-up longer than 1 month (n = 324), the preoperative VA of 0.68 ± 0.77 logMAR improved to 0.31 ± 0.46 logMAR postoperatively (P < .01). No intraoperative complications, systemic AEs, need to cease surgery prematurely, or conversion to IV sedation occurred. Five eyes (1.77%) required intraoperative supplemental sub-Tenon block administration, and 95% of patients who had a reoperation (n = 10) or fellow-eye surgery (n = 28) requested the same method of anesthesia without IV sedation. Conclusions: Vitreoretinal surgery with a sub-Tenon block and oral sedation can be safely performed without the support of an anesthesiologist. Additional trials are needed to further quantify patient comfort, surgeon experience, and complication rates.

Orbital compartment syndrome following primary scleral buckle surgery.

To illustrate a patient with orbital compartment syndrome following scleral buckle placement that was successfully treated with canthotomy and cantholysis. Observational case report. A 26-year-old male underwent a primary scleral buckle repair for a chronic rhegmatogenous retinal detachment. On post-operative day four, the patient presented to the emergency room with pain and increased intraocular pressure (IOP). Initial treatment with conservative IOP lowering agents was unsuccessful. The patient was diagnosed with delayed orbital compartment syndrome and was successfully managed with lateral canthotomy and inferior cantholysis in addition to aggressive steroid and antibiotic medical management. Following scleral buckle placement with sub-tenon's anesthesia block, there may be a delayed presentation of orbital compartment syndrome. Recognition and management of this rare complication is important for preventing irreversible blindness.

Ophthalmic Anesthesia and Related Complications in Vitreoretinal Surgery

The most critical anesthetic evaluation before vitreoretinal surgery is whether the patient and surgeon need local or general anesthesia. Local anesthesia techniques include topical, retrobulbar, peribulbar, and subtenon blocks. Performing analgesia and akinesia with appropriate anesthesia provides appropriate surgical conditions for the patient and physician, reducing surgical risks. In addition, since complications related to ophthalmic anesthesia may cause permanent visual impairment, managing perioperative complications is of great importance and requires experience.

Peri-operative Outcomes of Dexmedetomidine as an Additive to Subtenon Block Compared with Intravenous Dexmedetomidine for Patients Undergoing Vitreoretinal Surgery under General Anesthesia

Background: Several medications such as dexmedetomidine can be used as adjuvants with anesthesia to reduce the stress response during surgery resulting in good post-operative outcomes and safe recovery times. Aims: To compare the peri-operative outcomes of subtenon block with or without dexmedetomidine versus dexmedetomidine infusion as adjuvants to general anesthesia in subjects undertaking retinal operations. Design: A prospective randomized double-blind controlled clinical trial Patients and methods: Through the use of sealed opaque envelopes, 120 participants were randomly divided into three groups. Group SB received subtenon bupivacaine and lidocaine and IV infusion of normal saline. Group SD received subtenon bupivacaine, lidocaine, and dexmedetomidine and IV infusion of normal saline, whereas Group DI received subtenon saline and IV infusion of dexmedetomidine. Peri-operative hemodynamics and intra-ocular pressure were measured and recorded. Intra-operative bleeding, recovery times, post-operative sedation and pain scores, first analgesic times, total analgesic requirements, and the incidence of PONV and OCR were also assessed and documented. Statistical analysis: A prospective analysis of the collected data was performed using the SPSS program for Windows (version 22). Results: The results showed that IV dexmedetomidine has decreased cardiovascular responses to surgery as signified by decreased HR and MAP with a significant drop in IOP measurements before induction and after intubation, in comparison to other groups. Administering dexmedetomidine either or IV in the subtenon block led to a significant reduction in pain scores of the first post-operative six hours, the total pethidine consumption, and the surgical bleeding. Conclusion: When used as a supplement to general anesthesia during retinal surgery, dexmedetomidine is effective at reducing the airway response to tracheal intubation and extubation and maintaining peri-operative hemodynamic stability. Dexmedetomidine is also an efficient method for lowering intraocular pressure, surgical bleeding, and postoperative analgesic consumption with a better recovery profile. It can be administered either through IV infusion or combined with local anesthetics in subtenon block.

Role of hyaluronidase as an adjuvant in local anesthesia for cataract surgery.

Cataract surgery ranks among the commonest procedures performed worldwide. Approximately 51% of blindness worldwide is related to cataracts, affecting about 65.2 million people worldwide and more so in developing countries. Over the years, there has been a significant evolution in the surgical techniques of cataract extraction. The advancement in phacoemulsification machines, phaco-tips, and the availability of ophthalmic viscoelastic devices have played a substantial role in cataract surgery such that they are faster and more controlled than before. Similarly, anesthetic techniques in cataract surgery have advanced significantly from retrobulbar, peribulbar, and sub-Tenon's blocks to topical anesthesia. Though topical anesthesia eliminates the possible complications of injectable anesthesia, it is not suitable for use in uncooperative, anxious patients, pediatric age groups, and patients with cognitive disabilities. Hyaluronidase is an enzyme that breaks down hyaluronic acid in the retrobulbar tissue, facilitating uniform diffusion of the anesthetic drug and hastening the onset of anesthesia and akinesia. Hyaluronidase has been used in the last 80 years successfully as an adjuvant in retrobulbar, peribulbar, and sub-Tenon's blocks. Initially, the hyaluronidase enzyme was animal-derived and of bovine and ovine sources. Recombinant human-derived hyaluronidase, which has lesser allergic reactions, impurities, and toxicity, is now available. There is conflicting evidence regarding the efficacy of hyaluronidase as an adjuvant in retrobulbar and peribulbar blocks. This article summarizes a brief review of the literature on the role of hyaluronidase as an adjuvant in local anesthetic blocks in ophthalmic surgeries.

Good anesthetic for good esthetic: Blocks in oculoplasty.

: A good anesthesia not only makes the patient comfortable during surgery, but also has a huge impact on the postoperative recovery. It also makes the operating surgeon carry out each step of the surgery precisely and beautifully. The art of giving a good local anesthesia is to be learnt and practiced not only by anesthetists, but also by the practicing ophthalmologists. : This video gives an overview of anatomy in terms of the nerve supply of the orbit, the surface marking, and the techniques of giving regional and nerve blocks. : In this video, we describe the anatomy, the surface marking, the technique of regional anesthesia including peribulbar, retrobulbar, and subtenon blocks and of nerve blocks, specifically of facial, frontal nerve and its branches, infraorbital, nasociliary, infratrochlear, and dorsal nasal nerves, with their application in ocular plastic surgery. : This video highlights the essence of providing appropriate and good anesthesia so that the surgeon works in an optimal field with maximum comfort to the patients. Video link https://youtu.be/h8EgTMQAsyE.

Comparison between Effect of Dexmedetomidine and Dexamethasone as an Additive to Subtenon Block with General Anesthesia on Perioperative Outcomes for Pediatric Strabismus Surgeries

Comparison between Effect of Dexmedetomidine and Dexamethasone as an Additive to Subtenon Block with General Anesthesia on Perioperative Outcomes for Pediatric Strabismus Surgeries

BIS-monitoring as a tool for evaluation regional anesthesia in ophthalmology: pilot study

BACKGROUND: General anesthesia in vitreoretinal surgeries may be combined with ophthalmic blocks. Prolonged sub-tenon block (PSB) in extensive surgery ensures the continuous administration of a local anesthetic into the episcleral space; however, its effectiveness has not been evaluated.&#x0D; OBJECTIVE: To evaluate the effectiveness of sub-tenon block for vitreoretinal surgery in general anesthesia.&#x0D; MATERIALS AND METHODS: The pilot study included 24 patients. All patients underwent retinal detachment surgery under general anesthesia with sevoflurane for 90 min. Patients were randomized into two groups. In group 1, analgesia was induced with intravenous tramadol. In group 2, general anesthesia was combined with sub-tenon block, and 1% lidocaine was used continuously. Bispectral index (BIS) monitoring was employed for anesthesia depth assessment. The mean blood pressure and heart rates were estimated for the evaluation of the oculovisceral reflex block. The Student and WilcoxonBonferroni criterion was used for statistical analysis, and the statistical significance level was set at =0.05.&#x0D; RESULTS: The hemodynamic and consequently the degree of oculovisceral reflexes block had no statistically significant differences between the groups. The median BIS in groups 1 and 2 were 48.111.1 U and 42.68.2 U, respectively, and the difference between these values was statistically insignificant (p 0.05). However, in group 1, the BIS increased sharply during the laser phase. At this stage, the average BIS in groups 1 and 2 were 76.73.2 U and 40.46.9 U, respectively (p=0.001).&#x0D; CONCLUSION: BIS-monitoring can be used as an indicator of the effectiveness of ophthalmic regional blocks in further studies.

Contemporary Anesthesia Perspectives for Ophthalmic Surgery: A Brief Review

In recent decades there have been few changes in the anesthesia management of eye surgery. By contrast, the 21st Century has witnessed major advancements in ophthalmic surgery with the adoption of minimally-invasive techniques, technologic innovations, and an expanding population seeking eye care. These factors have impacted intraoperative exposure such that many procedures are now performed on more complex patients, and completed in quicker time. Furthermore, in pursuit of economic savings and patient satisfaction there is a trend to divert eye surgeries away from the in-hospital setting to ambulatory centers or office locations. From an anesthesia perspective, these changes have imposed a demand on providers to shorten operating room turnover times and accelerate patient discharge while maintaining high standards of patient safety. This review will address five new avenues of anesthesia care, each of which offer possibilities in accommodating facets of this new order surgical experience. First, remimazolam is an ultra-short acting benzodiazepine that produces a predictable period of hypnosis and rapid, full recovery of consciousness because of its short context-sensitive half-time and inactive metabolites. A single 3-5 mg dose produces 11-15 minutes sleep that may be ideal for brief ocular interventions. Second, nasal CPAP/BiPAP and high flow nasal oxygen devices expand the profile of patients appropriately managed at an ambulatory center. Since their application improves arterial oxygenation and delays the onset of apneic hypoxemia, they are advantageous for patients afflicted by morbid obesity or severe obstructive sleep apnea. Third, open globe injuries have traditionally been managed under general anesthesia. However, recent studies attest to regional anesthesia as a viable alternative for many ocular insults, particularly for the elderly and patients with major organ dysfunction or risk for pulmonary aspiration. Fourth, the sub-Tenon block is a cannula-based regional ophthalmic skill performed predeominantly by ophthalmic surgeons because it necessitates conjunctival incision and dissection. Recently described variations of an incision-free, easily mastered sub-Tenon approach are likely to be included in residency and fellowship instruction, and so become an invaluable component of the anesthesiology armamentarium. This review concludes with a concise overview of the a2 agonist dexmedetomidine with the focus directed on its uses as an adjunct for adult sedation, and advantage in children for premedication and control of emergence delirium.

Anesthesia for ophthalmic surgery: an educational review.

Selecting an anesthetic agent for ophthalmic surgery has crucial implications for the surgeon, anesthesiologist, and patient. This educational review explores the common classes of anesthesia used in ophthalmology. Additionally, we discuss the considerations unique to cataract, glaucoma, strabismus, orbital, oculoplastic, and ocular trauma surgeries. A comprehensive Embase search was performed using combinations of the subject headings "anesthesia", "eye surgery", "ophthalmology" and "cataract extraction", "glaucoma", "strabismus", "vitreoretinal surgery", "retina surgery", "eye injury", and "eyelid reconstruction". Topical anesthetics are the most commonly used form of ocular anesthesia, used in both an office and surgical setting, and carry a minimal side effect profile. Notably, topical anesthetics offer analgesia, but do not provide akinesia or amnesia. Regional blocks, such as are sub-Tenon's, peribulbar, and retrobulbar blocks, are used when akinesia is required in addition to analgesia. Recently, sub-Tenon's blocks have recently gained popularity due to their improved safety profile compared to other regional blocks. General anesthesia is considered for long, complex surgery, surgery in patients with multiple comorbidities, surgery in young pediatric patients, or surgery in patients intolerant to local or regional anesthetic. Anesthetizing the eye has rapidly evolved in recent years, supporting the safety, efficacy and comfort of ocular surgery. Since there are many viable options of anesthetics available for ophthalmic surgery, a robust understanding of the patients needs, the skill of the surgical team, and surgery-specific factors ought to be considered when creating an anesthetic plan for surgery.

Midazolam-Dexmedetomidine Combination versus Midazolam Alone for Premedication in Children Undergoing Pediatric Cataract Surgeries: a Double‐Blinded Randomized Controlled Trial

Background: Dexmedetomidine, a selective α2 agonist has shown promising results when used as a premedicant. This prospective randomized study evaluated the efficacy of two different premedication regimens in achieving a smooth conduct of anesthesia and optimum pain relief in pediatric cataract surgeries. Methods: 90 ASA I or II children, aged 1-6 years, scheduled for elective cataract surgeries were randomized to receive either 0.25 mg kg-1oral midazolam and 1μg kg-1 of intranasal dexmedetomidine (Group MD; n=45) or 0.5mg/kg oral midazolam followed by 0.02ml kg-1 intranasal saline drops (Group MS; n=45) 45 min prior to surgery. Drug acceptance, anxiety at parental separation and quality of mask induction was evaluated. Subtenon block was given to all the children. Intraoperative use of narcotics was avoided and used only as rescue drug. Primary outcome of the study was number of patients requiring rescue analgesia over 24-hour period. The secondary outcomes were time to first rescue analgesia, frequency of rescue analgesia, incidence of OCR and PONV. Results: 90% of the children in Group MD achieved MOAA/S ≤ 4 at 30 minutes versus 95% in Group MS. Drug acceptability, parental separation and mask acceptance were similar in both groups. Incidence of PONV and children who required rescue analgesia was less in MD group compared with MS group. There was no event of OCR in both groups. Conclusion: Premedication with combined IND and low dose oral midazolam is superior in decreasing postoperative analgesic requirements when compared to routine oral midazolam premedication alone in pediatric cataract surgeries under general anesthesia.

Надглазничный доступ перибульбарной анестезии как метод дополнительного обезболивания офтальмологических операций

Purpose. To evaluate the efficacy of additional peribulbar block with supraorbital approach with eyeball compression in retinal detachment surgery. Methods. 3 groups of patients, 10 people in each group were observed. In each group classical peribulbar anesthesia was performed. At the most painful moment, in group I a narcotic analgetic was applied. In group II the surgeon added a subtenon block, in group III a peribulbar block with supraorbital approach was administered. Results. According to the study, in the group where the additional peribulbar block was performed with the supraorbital approach, hemodynamic parameters remained stable, and patients did not feel any pain in comparison with the first two groups. Conclusions. This method of anesthesia provides a stable anesthetic effect during surgery and a long-term analgesic effect in the postoperative period. Key words: peribulbar blockade with supraorbital approach; eyeball compression; analgesic effect.

The effects of subtenon and intravenous dexmedetomidine on patients undergoing cataract surgery: A comparative randomized controlled double-blind study.

This prospective randomized study designed to evaluate the efficacy of dexmedetomidine either added to LA mixture or administered IV during subtenon block for cataract surgery. 75 patients, undergoing cataract surgery with subtenon anesthesia, were assigned randomly into three equal groups, Group I received subtenon bupivacaine 0.5% (1 ml) + lidocaine 2% (1 ml) + saline 0.9% (0.5 ml) and IV infusion of normal saline. Group II received subtenon bupivacaine 0.5% (1 ml) + lidocaine 2% (1 ml) + 0.5 μg/kg dexmedetomidine (0.5 ml) and IV infusion of normal saline. Group III received subtenon bupivacaine 0.5% (1 ml) + lidocaine 2% (1 ml) + saline 0.9% (0.5 μl) and IV infusion of 0.5 mg/kg dexmedetomidine over 10 min. before subtenon block. We recorded onset and duration of sensory and motor block, pain during subtenon injection, intraoperative hemodynamics, intraocular pressure, sedation and postoperative pain score. There was a significant decrease in the onset of action and an increase in the duration of sensory block in Group II. Pain during subtenon injection was significantly less in group III. Sedation Score was higher in Group III, while heart rate showed a significant reduction in the same group. The VAS was significantly decreased in group II. After the end of surgery, the intraocular pressure was significantly decreased in Groups II and III. Subtenon dexmedetomidine shortens onset time, prolongs sensory block durations and significantly decreases the postoperative pain score with hemodynamic stability, while, IV dexmedetomidine substantially reduces pain during subtenon block and produces intra-operative sedation.

Effect of Dexmedetomidine in Sub-Tenon's Block on Emergence Agitation in Pediatric Strabismus Surgery under Sevoflurane Anesthesia.

Background:Numerous unfavorable complications may occur with strabismus surgery as emergency agitation (EA), oculocardiac reflex (OCR), postoperative pain, and postoperative nausea and vomiting (PONV).Aims:This study was designed to evaluate the dexmedetomidine effect in sub-Tenon's block on EA in strabismus surgery in the pediatric population under sevoflurane anesthesia.Design:This was a prospective randomized double-blind clinical trial.Patients and Methods:Eighty American Society of Anesthesiologists (ASA) Physical Status Class I and II pediatric patients, in an age group ranging from 2 to 8 years of either sex, had strabismus surgery under sevoflurane anesthesia using laryngeal mask airway. Patients were divided randomly into two groups (each = 40). Sub-Tenon's block is performed in the operated eye with 0.5% bupivacaine (0.08 mL.kg−1) alone in Group B (bupivacaine group), and with 0.5% bupivacaine (0.08 mL.kg−1) and dexmedetomidine (0.5 μg.kg−1) in Group D (dexmedetomidine group). Hemodynamics were monitored, and OCR was recorded. Furthermore, postoperative EA (Pediatric Anesthesia Emergence Delirium and Cravero Scales), pain (Face, Legs, Activity, Cry, and Consolability), and incidence of PONV were recorded as well.Statistical Analysis:A prospective analysis of the collected data was performed using the SPSS program for Windows (version 26).Results:The dexmedetomidine group exhibited a lower EA incidence, pain, and PONV as compared to the bupivacaine group. No statistically significant differences regarding hemodynamics, OCR, or emergence time were found between both the groups.Conclusion:The addition of dexmedetomidine to bupivacaine in sub-Tenon's block can alleviate postoperative EA and nausea and vomiting with better pain management and hemodynamic stability in pediatric strabismus surgery under sevoflurane anesthesia.

The retrospective comparison of Sub-Tenon block techniques for prolonged vitreoretinal surgery

<h3></h3> Сочетание общей и местной анестезии считается оптимальным при микроинвазивных витрэктомиях. На данный момент нет рекомендаций, в которых было бы указано, какая методика местной анестезии предпочтительна. Как вариант предложена субтеноновая блокада. Если длительность операции превышает 90 мин, в субтеноновое пространство может быть введен препарат длительного действия левобупивакаин или установлен катетер для постоянной инфузии лидокаина. <h3>ЦЕЛЬ РАБОТЫ</h3> Сравнить эффективность двух методик субтеноновой блокады: продленной — лидокаином 1% и инъекционной —левобупивакаином 0,5% на фоне общей ингаляционной анестезии севофлураном. <h3>МАТЕРИАЛ И МЕТОДЫ</h3> В исследование включены 24 пациента, которым выполнена микроинвазивная витрэктомия под общей анестезией севофлураном длительностью 90—210 мин. В зависимости от методики обезболивания сформированы 2 группы по 12 человек. 1-я группа — пациенты, которым выполнена продленная субтеноновая анестезия лидокаином 1%, 2-я группа — пациенты, которым выполнена общепринятая субтеноновая инъекция левобупивакаина 0,5%. Оценивали активность окуло-кардиального и окуло-вазомоторного рефлексов по параметрам частоты сердечных сокращений и среднего артериального давления на различных этапах операции, а также потребность в миорелаксантах. Уровень болевого синдрома определяли после операции по цифровой рейтинговой шкале (NRS) от 0 до 10 баллов. Для статистического анализа использованы критерии Тьюки и Манна—Уитни с поправкой Бонферрони, уровень статистической значимости α принят равным 0,05. <h3>РЕЗУЛЬТАТЫ</h3> Средняя длительность операции составила у пациентов 1-й группы — 159,2±11,3 мин, у пациентов 2-й группы — 132,9±10,1 мин. Оценка активности окуло-кардиального рефлекса показала статистически значимые различия внутри 2-й группы, но не между группами. Оценка активности окуло-вазомоторного рефлекса продемонстрировала различия как внутри групп, так и между ними. Статистически значимые различия в показателях выявлены на всех трех этапах операции (<i>p</i>=0,006—0,009). Средняя доза рокурония бромида у пациентов 1-й группы составила 14,6±5,7 мг<i>,</i> 2-й группы — 20,8±8,0 мг. У пациентов 1-й группы болевой синдром выражен значительно меньше: средний уровень составил 0,08 балла, у пациентов 2-й группы — 0,75 балла. <h3>ВЫВОД</h3> При длительных витреоретинальных операциях продленная субтеноновая блокада лидокаином 1% является высоко эффективной и более безопасной методикой по сравнению с инъекционным введением левобупивакаина 0,5%; позволяет снизить дозу миорелаксанта; обеспечивает высокий уровень обезболивания.

Comparative study of silicone membrane simulator and animal eye models for sub-Tenon's block.

To compare and assess silicone membrane-based sub-Tenon's block (STB) simulator and animal eye model (goat's eye) for practicing STB in terms of anatomical similarity and feel of texture of eye layers. The study included 34 participants (26 learners and 8 consultants) from tertiary ophthalmic centres. The participants were divided into groups A and B. Group A performed STB on the goat's eyes before using the silicone membrane simulator. Group B performed STB on the simulator and further proceeded to the goat's eye. Participants had to rate the anatomical similarity and feel of the texture for the simulator model on a scale of 0-10 and share their preference between the two models. In group A, the scores given to the simulator model and the feel of texture of layers were 8.05 ± 0.88 and 7.97 ± 1.07, respectively, and the scores given to the animal model and the feel of texture of layers were 8.11 ± 0.97 and 8.21 ± 0.88, respectively. Group B participants scored the simulator model and feel of texture of layers with 8.13 ± 0.95 and 8.25 ± 0.99, respectively. Overall, 89% participants preferred the simulator; the reasons included ease of usage, helpful warning system, absence of biological waste, and facility for repeatable training. The study validated anatomical accuracy, preference, and ability of usage of the STB simulator. For broader usage, further study involving higher number of participants is recommended.

Patient preference and pain-reported outcomes for topical versus subtenon anesthetic for cataract surgery.

PURPOSE:Cataract extraction and lens implantation is the most common surgical procedure performed worldwide, with surgeons opting for either a topical or a subtenon anesthetic in majority of cases. While complication rates and pain scores have been previously examined in a bid to determine which modality was better, patients who have had both eyes operated upon under different techniques have never previously been asked which method they prefer. We undertook this study to fill in this crucial gap in our knowledge.METHODS:This is a retrospective study of patients who have undergone bilateral cataract surgery with one eye operated on with topical anesthesia and the other eye with subtenon anesthesia. Patients were identified who had had surgery undertaken in the previous 6 months at Singleton Hospital, Swansea, where both eyes had been operated upon using different anesthetic techniques. Telephone interviews with these patients were performed and their pain scores recorded on a scale from 0 (no pain) to 10 (severe pain) for both eyes, with the patients then being asked which the method of anesthetic they preferred. Statistical analysis of pain scores was compared using Wilcoxon rank-sum testing.RESULTS:One hundred and fifty-two patients in total were identified. One hundred and forty-one of the applicable patients participated in the study. Of these, 78 patients received topical anesthesia for their first operation and 63 had subtenon block for their first operation. The mean pain scores reported for surgery with topical anesthesia and subtenon block were 2.30 and 1.38, respectively. The pain data were analyzed using a Wilcoxon signed-rank test, returning a z-score of 4.038. This result therefore suggests that patients experience statistically significantly less pain from cataract surgery when given a subtenon block. Patients expressed a preference for subtenon anesthesia, with 70% preferring subtenon block, 23% preferring topical anesthesia, and 7% having no preference.CONCLUSIONS:Patients report less pain with subtenon anesthesia compared with topical anesthesia in cataract surgery, where both eyes were operated upon with different anesthetic techniques. This is the first study in which patients who have had both anesthetic techniques performed independently for cataract surgery have had their pain scores reported and statistically analyzed.

A Mannequin-Based Training System With Integrated Sensors for Ophthalmic Sub-Tenon Anesthesia

Sub-tenon ophthalmic blocks are gaining popularity for ophthalmic anesthesia but have no suitable systems available for training. In this article, the design and development of the first mannequin-based system to train and evaluate an ophthalmic anesthesiologist to perform the sub-tenon block correctly is presented. The system has integrated sensors with new sensing schemes for needle tip tracking and detection of errors incurred by the trainee. An integrated, conductive silicone-based eye model sensor is presented in this article. The model replicates the human ocular anatomy, and the embedded sensors within the eye model help to classify, assess, and evaluate the performed procedure. The developed system was also validated in a pilot clinical study for naturality and usage in a clinical setting with 37 ophthalmic anesthetists. The system recorded 98.3 % accuracy assessing the performed procedure during the clinical study, and the participants rated the naturality of the system with a score of 8.0 ± 0.63 (on a scale of 10) ( p <; 0.01). 89 % of the participants and experienced sub tenon block instructors who previously used provisional animal eye-based models for training preferred the training system for its usage of anatomically accurate models and effective warning systems that evaluate the performed procedure.

Effect of pterygopalatine blockade on perioperative stress and inflammatory outcomes following paediatric cataract surgery

BackgroundGeneral anesthesia is required to perform pediatric cataract surgery. To reduce severity of surgical intervention and postoperative complications, regional techniques have been concomitantly used. The traditional regional ophthalmic techniques are...