[The development of laser technologies in vitreoretinal surgery (publications review)].

The article presents review of scientific publications on development of laser treatment methods in vitreoretinal surgery. The use of photo-therapy in medicine dates back to ancient times, when people began to use sunlight as treatment of various diseases. The heyday of photo-therapy falls on the second half of the XIX century, which was associated with the invention of first electric lamps. In 1960, T. Maiman developed the world's first laser, revolutionizing precision and control of light delivery. This was the beginning of heyday of laser surgery primarily in ophthalmology, where potential of lasers was instantly recognized. The subsequent discovery of argon laser in 1964 by W. Bridges (USA) marked new era in retinal photo-coagulation. Then new types of lasers with various systems of delivering laser radiation appeared that significantly expanded range of application of laser technologies in ophthalmology and vitreoretinal surgery. Currently, the lasers are applied in oculoplasty, refractive and corneal surgery, in laser support of phacoemulsification of cataract, in treatment of glaucoma, in laser coagulation of retina and thermotherapy. In vitreoretinal surgery laser technologies remain at the level of the XX century. Thus, they are still applied only for endolaser coagulation of retina. And this despite the fact that there is immense potential for applying lasers as "laser scalpel" to remove vitreous humor, epiretinal fibrosis, retinotomy and choroidotomy.

Ketamine versus midazolam as an adjuvant to peribulbar block using a single inferonasal injection in patients undergoing vitreoretinal surgery: A randomized controlled trial.

INTRODUCTION AND OBJECTIVES: This study aimed to assess the safety and efficacy of midazolam and ketamine as adjuvants to the peribulbar block in vitreoretinal surgeries. PATIENTS AND METHODS: This randomized controlled trial included 93 adult patients undergoing vitreoretinal surgeries performed with peribulbar anaesthesia. Patients were randomly allocated to 3 groups (31 participants each): control (standard anaesthetic mixture), midazolam (standard mixture + midazolam), and ketamine (standard mixture + ketamine). The primary outcomes were onset of globe akinesia and duration of analgesia. Secondary outcomes were duration of motor blockade, onset of corneal anaesthesia and lid akinesia, and changes in vital data (blood pressure, oxygen saturation, and pulse rate). RESULTS: The ketamine group vs. the control and midazolam groups showed the most rapid onset of lid and globe akinesia (p < 0.001) and corneal anaesthesia (0.7 ± 0.2 vs. 1.5 ± 0.5 and 1.2 ± 0.4, respectively; p < 0.001) and the longest duration of both analgesia (3.7 ± 0.6 vs. 2.3 ± 0.4 and 3.1 ± 0.6, respectively; p < 0.001) and akinesia (3.8 ± 0.5 vs. 3.0 ± 0.4, and 3.7 ± 0.5, respectively; p < 0.001). The midazolam group showed better outcomes than controls, but the drug was less effective than ketamine. There were no significant differences in vital data among groups (p > 0.05). CONCLUSIONS: Ketamine is an effective adjuvant for peribulbar blockade. It enhances both motor and sensory blockade by hastening onset and prolonging duration. These effects are desirable in lengthier ophthalmic procedures such as vitreoretinal surgeries. The effects of ketamine were superior to those of midazolam.

TRANSCARUNCULAR DOUBLE INJECTION TECHNIQUE FOR PERIBULBAR ANESTHESIA IN VITREORETINAL SURGERY.

PURPOSE: Local anesthesia is commonly adopted in vitreoretinal surgery to reach painless and akinesia surgical condition. Currently, peribulbar anesthesia (PBA) and subtenon injection (STN) are the most widely used methods. We propose a transcaruncular double injection peribulbar technique (TRS) and aim to compare it with both standard PBA and STN injections. METHODS: A total of 105 patients underwent TRS, PBA, or STN. A numerical rating scale was used to assess preoperative, postoperative, and intraoperative pain. Best akinesia score and onset and duration of akinesia were evaluated by two independent graders. The need for supplementary injection was also registered. RESULTS: TRS group was characterized by a lower intraoperative numerical rating scale variation and absolute numerical rating scale score both at the beginning of surgery ( P 0.046), after 30 minutes ( P 0.032), and at the end of surgery ( P 0.002) compared with the other groups. The TRS group also showed better akinesia score ( P 0.004), fastest onset ( P 0.002), and longer duration ( P 0.042) compared with both PBA and STN. No injection-related complications were reported in the three groups. CONCLUSION: The newly proposed transcaruncular PBA provided superior pain control and akinesia level with no additional adverse events.

COMPARISON OF PAIN EXPERIENCE IN PATIENTS UNDERGOING SUB-TENON'S ANESTHESIA VERSUS PERIBULBAR ANESTHESIA DURING ELECTIVE VITREORETINAL SURGERY.

PURPOSE: To assess and compare the patients' discomfort and pain experienced during anesthesia, pars plana vitrectomy, and 24 hours postoperatively after sub-Tenon's injection (STI) versus peribulbar block (PB) in elective vitreoretinal surgery. METHODS: Retrospective study involving 80 patients who underwent elective vitreoretinal surgery receiving either PB (Group 1, n = 40) or STI (Group 2, n= 40) between January 2021 and March 2022. Patients' pain experienced during the procedure and 24 hours postoperatively were assessed using a pain scale and a two-section questionnaire. One hour postoperatively, patients were asked to rate the level of pain they felt during the entire procedure by pointing at a 0 to 100 Visual Analog Scale. Subsequently, patients answered a two-section questionnaire regarding pain and discomfort felt 24 hours postoperatively. RESULTS: According to Visual Analog Scale measurements, patients experienced significantly more pain during PB than during STI 1 hour after surgery. Patients undergoing PB experienced more pain than those who underwent STI, experiencing burning and discharge feeling. Patients undergoing STI had a lower pain level score 24 hours postoperatively despite similar discomfort. CONCLUSION: Sub-Tenon's injection has a lower pain score than PB during the procedure and 24 hours postoperatively, representing a valuable procedure to deliver analgesia in vitreoretinal surgery.

Iatrogenic central retinal artery occlusion following retrobulbar anesthesia with adrenaline for vitreoretinal surgery: a case report.

BACKGROUND: We describe a patient presenting with central retinal artery occlusion (CRAO) of the right eye after retrobulbar anesthesia with adrenaline for macular pucker surgery. CASE PRESENTATION: The patient, a 67-year-old Caucasian man, developed a CRAO postoperatively by the next-day control likely due to the retrobulbar injection of a combination of Xylocaine and Bupivacaine with adrenaline as anesthetic. CONCLUSIONS: The addition of adrenaline to the standard anesthetic solution could be a risk factor for serious complications, such as CRAO.

Haemorrhagic complications following cataract and vitreoretinal surgery with sub-Tenon's block in patients receiving non-vitamin K oral anticoagulant agents: A prospective audit.

There is a lack of data to support either continuation or interruption of non-vitamin K oral anticoagulants for cataract and vitreoretinal surgery. A prospective audit was undertaken of 291 patients undergoing cataract surgery or vitreoretinal surgery, predominantly under sub-Tenon's block, while continuing these agents. The median time from last non-vitamin K oral anticoagulant dose to the insertion of sub-Tenon's block was five hours. No patient required emergency reversal of anticoagulation. There were no sight-threatening complications in the immediate perioperative period, although two vitreoretinal patients (3.8%) had a moderate haemorrhagic complication on day five, and two cataract patients (0.8%) had a minor haemorrhagic complication on days one and 14 postoperatively. Despite continuing their non-vitamin K oral anticoagulants, three (1%) cataract patients had a moderate thromboembolic complication within the 30-day postoperative period. The risk of haemorrhagic complications associated with continuation of anticoagulation with non-vitamin K oral anticoagulants for cataract and vitreoretinal surgery is low, and this audit supports the continuation of non-vitamin K oral anticoagulants for our patients having cataract and vitreoretinal surgery.

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.

Novel vitreous substitutes: the next frontier in vitreoretinal surgery.

PURPOSE OF REVIEW: After removing the native vitreous during vitreoretinal surgery, an adequate substitute is required to ensure homeostasis of the eye. Current clinically used endotamponades (silicone oil, gases, semifluorinated alkanes) are effective in promoting retinal reattachment, but lead to complications such as emulsification, prolonged inflammation, blurred vision, raised intraocular pressure, cataract formation or the need for revision surgery. The aim of this review is to provide an update on novel vitreous substitutes with a focus on polymer-based systems. RECENT FINDINGS: Polymeric hydrogels provide favourable properties such as high water content, optical transparency, suitable refractive indices and densities, adjustable rheological properties, injectability, biocompatibility and their ability to tamponade the retina via viscosity and swelling pressure, comparable to the native human vitreous body. Here, vitreous replacement strategies can be divided into chemically or physically crosslinked hydrogel systems that are applied as preformed or in-situ gelling matrices. SUMMARY: Several hydrogel-based vitreous substitutes have already been positively evaluated in preclinical tests and have the potential to enter the clinical phase soon.

The effects of active warming on perioperative inadvertent hypothermia in patients undergoing vitreoretinal surgery under local anesthesia.

Purpose: Perioperative inadvertent hypothermia (PIH) is the decrease in core temperature below 36°C. We aimed to assess whether PIH develops in patients operated under local anesthesia (ULA) for vitreoretinal surgery in the operating room and investigate active warming efficacy. Methods: Seventy-two patients were divided into two groups: Group 1 contained unwarmed patients (n = 36), and Group 2, warmed patients (n = 36). The core temperatures, heart rate (HR), and mean arterial pressure (MAP) of the patients were measured at the beginning of surgery, after 20 min, 40 min, 1 h, at the end of the operation, and during the postoperative period. Results: PIH incidence was 44.6% in Group 1, whereas no hypothermia was observed in Group 2. Patient temperatures at 20 min (P = 0.001), 40 min (P < 0.001), 1 h (P < 0.001), the end of the operation (P < 0.001), and the postoperative period (P < 0.001) were significantly higher in Group 2 than in Group 1. Patient HRs at the end of the operation and during the postoperative period were significantly lower in Group 2 (P = 0.005) than in Group 1 (P < 0.001). The intraoperative 40th (P = 0.044) and 60th (P < 0.001) minutes, end of operation (P < 0.001), and postoperative MAP (P < 0.001) values of Group 1 were significantly higher than those of Group 2. Conclusion: PIH may develop in patients operated ULA, especially with a low ambient temperature. Actively warming may help prevent the harmful effects of PIH.

Intra-operative scleral rupture during 23 gauge pars plana vitrectomy: a case report.

BACKGROUND: Use of perfluorocarbon liquid (PFCL) has been increasingly growing as an adjuvant in vitreo-retina surgeries. Some commonly encountered complications with its use include subretinal migration, formation of sticky silicone oil or retained PFCL in vitreous cavity and anterior chamber. Scleral rupture during PFCL injection has a rare occurrence. We report an unexpected event of scleral rupture during PFCL injection and discuss the management challenges faced by the surgeon. CASE PRESENTATION: A 66 year indo-aryan male was undergoing pars-plana vitrectomy (PPV) with diagnosis of subtotal rhegmatogenous retinal detachment (RD) with Proliferative Vitreo-retonipathy (PVR)-B. After near total vitrectomy PFCL was being injected and then there was sudden poor visualization of fundus with development of bullous RD and globe hypotony. The surgeon was not able to figure out the cause of hypotony and air was switched on in the infusion cannula. This further complicated the situation resulting in migration of air in the anterior chamber, posterior dislocation of intraocular lens complex, 180° inferior retinal dialysis and ballooning of the conjunctiva which gave a clue of probable scleral rupture. Conjunctival peritomy was performed superiorly and scleral defect was noted. Intraocular tissue incarceration and air leak was visible from the wound. This confirmed scleral rupture during PFCL injection. Repositioning of incarcerated retina was not possible and retinectomy was performed followed by repair of scleral rupture with lots of difficulty in a vitrectomised eye. CONCLUSION: PFCL injection, a crucial step of vitreoretina surgery, should be performed slowly with extreme caution maintaining an optimal intraocular pressure to prevent devastating complications like scleral rupture.

Evaluating the effectiveness of localized sub-Tenon's anesthesia in 23-gauge vitreoretinal surgery.

PURPOSE: To evaluate the effectiveness of localized sub-Tenon's anesthesia for pain control during 23-gauge vitreoretinal surgery. METHODS: Eighty patients were randomly divided into two groups as localized sub-Tenon's (group 1, n = 41) and retrobulbar (group 2, n = 39) anesthesia groups. In group 1, a small volume of anesthetic was injected into the sub-Tenon's capsules at the trocar entry sites. The 23-gauge vitreoretinal surgery was performed in all patients. In both groups, the pain levels during the surgical steps were evaluated using the visual analog pain scale. RESULTS: Patients in group 1 experienced less pain than group 2 patients did during placement of the trocars and scleral depression (p = 0.041, p = 0.029). Pain during laser photocoagulation was higher in group 1 (p = 0.008). There was no serious complication due to anesthesia or surgery. CONCLUSION: Localized sub-Tenon's anesthesia is as effective as retrobulbar anesthesia in many steps of vitreoretinal surgery for providing pain control. It can be considered an alternative form of local anesthesia.

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.

Efficacy and Safety of a Novel Blunt Cannula Trans-Sub-Tenon's Retrobulbar Block for Vitreoretinal Surgery.

PURPOSE: To evaluate a novel trans-sub-Tenon's retrobulbar block (TSTRB) compared to sub-Tenon's block (STB) and peribulbar block (PBB) anesthesia for vitreoretinal surgery. METHODS: This study was a prospective evaluation of cases undergoing TSTRB, STB, or PBB. The Kallio scale and Brahma scales were used to score hemorrhage and extraocular motility, respectively. Pain was documented on a visual analog score graded (1-10) at induction, intraoperatively, and postoperatively, any confounding variables were noted. RESULTS: Seventy eyes have been used in this analysis, of which TSTRB was used in 37% (n = 26), PBB in 34% (n = 24), and STB in 29% (n = 20). Postoperative analgesia was required by 10% (n = 2) of STB and 8% (n = 2) of PBB; none of the TSTRB cases required analgesia (P = 0.003). The mean volume required with each technique was as follows: TSTRB, 4.8 ml; STB, 5.3 ml; and PBB, 10.4 ml (P = 0.030). The volume of anesthesia was correlated with the level of proptosis and even more important affected the ease of surgery most (P = 0.005). Akinesia was greatest with TSTRB > PBB > STB (P = 0.040). There were no complications such as brainstem anesthesia, globe perforation, or retrobulbar hemorrhage. CONCLUSION: Intentionally extending a STB into the retrobulbar space, via a TSTRB fenestration utilizes a familiar skill set. TSTRB produced the best levels of reduced kinesia during surgery and increased duration of postoperative analgesia. The technique uses a small-volume anesthesia.

Evaluation of the effect and safety of dexmedetomidine as an additive to local anesthesia in peribulbar block for vitreoretinal surgery.

Purpose: We conducted a prospective, randomized study to evaluate the efficacy of dexmedetomidine as an additive to peribulbar block for vitreoretinal surgery in terms of onset time of block, hemodynamic stability profile, patient comfort, and surgeon satisfaction. Methods: One hundred patients of American Society of Anesthesiologists grade 1 and 2 scheduled for vitreoretinal surgery were randomly assigned into two groups: control group (n = 50) received lignocaine bupivacaine block, and Dex group (n = 50) received lignocaine bupivacaine plus 20 µg dexmedetomidine peribulbar block. Information regarding time for onset of block, hemodynamic data, visual analog scale for pain, sedation levels, total duration of surgery, and surgeon satisfaction levels were collected. Results: All the demographic characteristics including age, gender, American Society of Anesthesiologists grade, onset of anesthesia, and duration of surgery were comparable in both groups. At the baseline, there was no statistically significant difference in heart rate, mean arterial pressure, diastolic blood pressure, and respiratory rate between the two groups, with a difference noted in systolic blood pressure at the baseline. There was significant difference noted in the systolic blood pressure and mean arterial pressure at different time intervals with a decreasing trend as time progressed. The mean sedation score was significantly higher in the Dex group than that in the control group. The surgeon satisfaction was higher in the Dex group than that in the control group. Conclusion: Dexmedetomidine is a useful and safe drug in combination with lignocaine bupivacaine in peribulbar for vitreoretinal surgery as it maintains hemodynamic stability and provides sedation, which enables full cooperation and potentially better operating conditions.

Gross anterior segment ischaemia following vitreoretinal surgery for sickle-cell retinopathy.

We report the case of a 32-year-old Afrocaribbean man with known stage 3 proliferative sickle-cell retinopathy who presented with a mixed picture of tractional and rhegmatogenous macula off detachment. He underwent left primary 25 g vitrectomy with silicone oil, delamination and endolaser photocoagulation under a general anaesthetic. He, however, presented 48 hours postoperatively with gross anterior segment ischaemia. His pain and ocular signs settled over the course of a few days following administration of supplemental oxygen, oral steroids, analgesia and intravenous hydration. Examination showed resolution of his proptosis and orbital signs as well as anterior segment inflammation. He remains under follow-up.

Comparison of topical and retrobulbar anesthesia in terms of pain experience during silicone oil extraction.

PURPOSE: To compare the use of topical anesthesia and retrobulbar anesthesia during silicone oil removal with a mixed pars plana technique, through evaluating the pain experience of patients. METHODS: We selected patients according to their behavior during previous vitreoretinal surgery and ophthalmologic examinations and divided them into two anesthesia groups: topical (n=36) and retrobulbar (n=33). We used a mixed technique for the passive removal of silicone oil in both groups. During each step of the surgery, the patients' pain experience and the surgeon's comfort were scored according to a pain scale. RESULTS: The pain experienced during the application of the anesthesia was significantly greater in the retrobulbar group (p<0.001). The topical group experienced greater pain during trocar insertion (p<0.001). There was no significant difference between the groups regarding the overall pain experience or complications. CONCLUSIONS: The pain experience of the selected patients during silicone oil removal was comparable between the topical and the retrobulbar anesthesia. Topical anesthesia with the mixed pars plana technique is an effective and safe alternative option for silicone oil removal surgery.