Brainstem Anesthesia During Retrobulbar Block: An Eye-Opener Clinical Case.

The use of a retrobulbar anesthetic block for surgery of the posterior chamber is a common, effective, and safe practice, although not without risks. This clinical case aims to describe one of the most feared complications of this ophthalmic block, which demands a high degree of suspicion and agility for proper diagnosis and management. A 91-year-old female patient, physical status ASA III, presents for vitrectomy via pars plana of the left eye due to retinal detachment. Light sedoanalgesia was performed, as well as a left retrobulbar block with 5 mL of local anesthetic. Approximately two minutes after the injection of the local anesthetic, she developed a sudden clinical decline of consciousness, accompanied by bilateral photoplegic mydriasis, sinus tachycardia, and hypertension, followed by central apnea. Orotracheal intubation and connection to a ventilatory prosthesis were performed, maintaining adequate oxygenation, ventilation, and hemodynamic stability. No abnormal findings were found in complementary diagnostic methods. The condition progressively reversed, with a gradual return to the initial state of consciousness, and it was possible to successfully extubate the patient after four hours. The patient remained stable, under surveillance, and was discharged home after 48 hours with no neurological impairment or ophthalmological complications. The clinical findings are compatible with brainstem anesthesia, explained by the dispersion of the local anesthetic into the subarachnoid space, through an inadvertent puncture of the ophthalmic artery or the meninges that involve the optic nerve. Although this event is a rare complication, a low threshold of suspicion should be maintained, given the potential severity of the clinical condition. Early recognition should be followed by a systematic A-B-C-D-E approach, and the outcomes are often favorable. Careful surveillance and monitoring should accompany the performance of ophthalmic surgical procedures, and the presence of an anesthesiologist is essential for the quality of the services provided and patient safety.

Comparison of preoperative retrobulbar bupivacaine and postoperative subcutaneous liposome-encapsulated bupivacaine on postoperative analgesia in dogs undergoing enucleation.

OBJECTIVE: To compare the effectiveness of preoperative bupivacaine inferotemporal retrobulbar blocks to postoperative liposome-encapsulated bupivacaine (Nocita) line blocks for analgesia following enucleation. ANIMALS: 39 client-owned dogs (40 eyes) presenting to the Ophthalmology Service for enucleation. METHODS: Dogs were randomly assigned to receive either a preoperative inferotemporal retrobulbar block with 0.5% bupivacaine or a peri-incisional line block with liposome-encapsulated bupivacaine (Nocita) at closure. Patients underwent unilateral enucleation and were hospitalized for 24 hours after surgery. Pain scores were performed by a masked observer with the Glasgow Composite Measure Pain Scale and the University of Wisconsin Ocular Pain Scale at 0.25, 0.5, 1, 2, 4, 6, 8, and 24 hours following surgery. Intraoperative use of blood pressure and anesthetic support mediations as well as need for rescue pain control were recorded and compared between groups. RESULTS: There was no significant difference in rescue rates between treatment groups. When comparing the use of medical intraoperative heart rate, blood pressure, or anesthetic plane support, there were no significant differences in use between groups. CLINICAL RELEVANCE: Use of preoperative bupivacaine retrobulbar blocks and postoperative Nocita line blocks were equally effective at postoperative pain control with similarly low complication rates.

Acute reversible bilateral hearing loss after retrobulbar anesthesia.

This is the first reported case who had bilateral reversible hearing loss after regional anesthesia (RA) without a procedural sedoanalgesia. Furthermore, 20% lipid emulsion infusion (LEI) was first used in the treatment of a patient with hearing loss as an indicator of impending brainstem anesthesia. The ophthalmologist had performed a retrobulbar block without any difficulties to a 55-year-old the patient who undergone pars plana vitrectomy. A combination of lidocaine and bupivacaine was injected slowly through a 23G, 1.5-inch needle. Few minutes later, the patient experienced sudden bilateral hearing loss and, subsequently, mental confusion and mild respiratory distress. Local anesthetic toxicity to the predominantly brainstem was the diagnosis. Consequently, 20% LEI was administered, and his hearing loss gradually improved within a few hours. Prompt intervention is crucial in case of severe systemic complications of RA. LEI might be beneficial to halt the deepening of brainstem toxicity.

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.

The Outcomes of an Opioid-Free Anaesthetic Plan in Fourteen Dogs Undergoing Enucleation Using an Ultrasound-Guided Supra-Temporal Retrobulbar Block: A Retrospective Case Series.

The objective of this retrospective case series is to report the outcomes of an opioid-free anesthetic plan in dogs undergoing enucleation surgery. A total of 14 dogs were admitted for enucleation between March and December 2020. A multimodal approach to perioperative analgesia was used, with a focus on retrobulbar anesthesia. A combination of an ultrasound-guided retrobulbblock with a supratemporal approach in association with ketamine, dexmedetomidine and non-steroidal anti-inflammatory drugs was used in the reported cases. Intraoperative nociception was defined as an increase of 20% from the baseline in one or more of the following parameters: heart rate, respiratory rate or mean arterial pressure. An ultrasound-guided retrobulbar block in an opioid-free anesthesia regime was effective at managing the perioperative analgesia of 13 out of 14 dogs. In only one case, a bolus of fentanyl was administered to treat intraoperative nociception. Recovery was uneventful in all the dogs, and the postoperative pain scores remained below the intervention threshold at all time points. To the authors' knowledge, this is the first reported case series of opioid-free anesthesia for enucleation in dogs.

Possible Brainstem Anaesthesia in a Cat after Ultrasound-Guided Retrobulbar Block.

A 13-year-old neutered, blue-eyed female Siamese cat with a bodyweight of 4.8 kg was admitted for enucleation of the right eye. An ultrasound guided retrobulbar block with 1 mL of ropivacaine was performed under general anaesthesia. When the tip of the needle was visualised inside the intraconal space, negative aspiration of the syringe before injection and no obvious resistance during injection were confirmed. Instantly, after ropivacaine was administered, the cat became apnoeic, and its heart rate and the blood pressure increased significantly for a short period of time. During surgery, the cat needed cardiovascular support to maintain blood pressure and was under continuous mechanical ventilation. Spontaneous breathing returned 20 min after the end of anaesthesia. Brainstem anaesthesia was suspected, and after recovery, the contralateral eye was examined. A reduced menace response, horizontal nystagmus, mydriasis, and absence of the pupillary light reflex were present. The following day, mydriasis was still present, but the cat was visual and was discharged. The inadvertent intra-arterial injection of ropivacaine was suspected to be the cause of the spread into the brainstem. To the current authors' knowledge, possible brainstem anaesthesia has only been reported in a cat 5 min after a retrobulbar block but never instantly.

Effect of Volumes of Solutions on Intraocular Pressure During Intravitreal Injection of Low Dose Gentamicin in Horses With Recurrent Uveitis: A Randomized Controlled Study.

Horses with recurrent uveitis can be treated by intravitreal injection of low dose gentamicin under sedation and after local anesthetic techniques including the retrobulbar nerve block. Since it is reported that retinal degeneration can be secondary to an acute increase of intraocular pressure (IOP), the current randomized controlled study was carried out in order to investigate the changes in IOP following retrobulbar anesthesia, with two different volumes of local anesthetic (lidocaine) solution (10 and 5 mL), and intravitreal injection of 6 mg gentamicin in two different volumes of solution (0.3 and 0.15 mL). Multivariate regression showed that IOP was significantly lower in the pathologic eye at baseline (estimated effect size -6.1 mmHg; P = .0001) and after sedation (estimated effect size -9.4 mmHg; P < .0001). The IOP was significantly higher after a 10 mL block (P .0002) but this effect was very small (+0.5 mmHg). There was no significant difference in IOP after the injection of 0.15 or 0.3 mL solution of gentamicin. There was no significant combined effect of the volume of local anesthetic used for the block and the volume of the gentamicin solution. Since the expected anesthetic effects (desensitization and akinesia) were met in all cases, the smaller volume of 5 mL of lidocaine solution would be preferable for retrobulbar block for intravitreal injections, while intravitreal injections volumes of 0.15 and 0.30 mL can be used indifferently.

The effect of local anesthetic solution volume applied in retrobulbar block in cataract surgery on the duration of anesthesia and patient comfort / Efeito do volume da solução anestésica local aplicada no bloqueio retrobulbar na cirurgia de catarata na duração da anestesia e no conforto do paciente

Abstract Objective: To compare the use of 2 different local anesthetic solution (LAS) volumes of 1.5 mL and 3 mL in retrobulbar block in patients undergoing cataract surgery in terms of anesthesia, akinesia, and pain levels. Methods: 80 patients between 18-90 years old, ASA I-II-III, were included in the study. For retrobulbar anesthesia, 1.5 mL LAS was applied to one group (Group LV), and 3 mL LAS to the other group (Group HV). The patients' ocular and eyelid motion scores were evaluated and recorded in the first, third, fifth, and tenth minutes after the block, and at 30-minute intervals for 4 hours post-operatively. One day later, the first hour of analgesic need and the number of times they took analgesic agents were asked and recorded. In addition, side effects were questioned and recorded. Results: The 39 (48.75%) patients were male and 41 (51.25%) patients were female. The criteria determined in terms of ocular motor score after the retrobulbar block (ocular motor score≤4) were met in 92.5% of patients in Group LV in all patients in Group HV, and the time to fulfill the determined criteria in Group HV was found to be significantly lower compared to Group LV (p=0.004). The movements of the eye in all direction except the inward movement recovered in Group LV in a significantly shorter time than Group HV (p=0.004). There was no significant difference in pain levels and side effects between the groups (p=0.34). Conclusions: After 1.5 mL LAS administration in retrobulbar block, adequate akinesia was not achieved in about one tenth of patients, but no significant difference was found between 1.5 mL and 3 mL LAS volumes in analgesic efficacy and side effects.

Resumo Objetivo: Comparar o uso de 2 volumes diferentes de solução anestésica local (LAS) de 1,5 mL e 3 mL no bloqueio retrobulbar em pacientes submetidos à cirurgia de catarata em termos de anestesia, acinesia e níveis de dor. Métodos: 80 pacientes entre 18 e 90 anos, ASA I-II-III, foram incluídos no estudo. Para anestesia retrobulbar, 1,5 mL de LAS foi aplicado em um grupo (Grupo LV) e 3 mL de LAS no outro grupo (Grupo HV). Os escores de movimento ocular e palpebral dos pacientes foram avaliados e registrados no primeiro, terceiro, quinto e décimo minutos após o bloqueio e em intervalos de 30 minutos por 4 horas no pós-operatório. Um dia depois, a primeira hora de necessidade de analgésico e o número de vezes que eles tomaram analgésicos foram solicitados e registrados. Além disso, os efeitos colaterais foram questionados e registrados. Resultados: 39 (48,75%) pacientes eram do sexo masculino e 41 (51,25%) do sexo feminino. Os critérios determinados em termos de escore motor ocular após o bloqueio retrobulbar (escore motor ocular≤4) foram atendidos em 92,5% dos pacientes do Grupo LV em todos os pacientes do Grupo HV, e foi encontrado o tempo para atender aos critérios determinados no Grupo HV ser significativamente menor em comparação ao grupo LV (p = 0,004). Os movimentos do olho em todas as direções, exceto o movimento interior, se recuperaram no Grupo LV em um tempo significativamente menor que o Grupo HV (p = 0,004). Não houve diferença significativa nos níveis de dor e efeitos colaterais entre os grupos (p = 0,34). Conclusões: Após administração de 1,5 mL de LAS no bloqueio retrobulbar, não foi alcançada acinesia adequada em cerca de um décimo dos pacientes, mas não foi encontrada diferença significativa entre os volumes de 1,5 mL e 3 mL de LAS na eficácia analgésica e efeitos colaterais.

Comparative Study of Retrobulbar Block versus Ketamine Infusion during Eye Enucleation/Evisceration (Randomized Controlled Trial).

BACKGROUND: The aim of this study is to compare the safety and efficacy of retrobulbar block versus intraoperative ketamine infusion in eye enucleation or evisceration under general anesthesia. MATERIALS AND METHODS: Forty-five patients belonging to American Society of Anesthesiologists Physical Status I and II undergoing eye enucleation or evisceration were randomly allocated to three equal groups (15 patients each). General anesthesia was used as the standardized technique in all patients. Group R received a single retrobulbar injection, Group K received intravenous ketamine infusion, and Group C received normal saline with the same rate of ketamine infusion. Intraoperative heart rate and mean arterial pressure, recovery time, postoperative pain score, time to first rescue analgesic, number of patients who required rescue analgesia, and any adverse events were reported. RESULTS: Postoperative pain Visual Analog Scale was significantly lower in R and K groups in comparison to the C group and was significantly higher in K than R group at 3, 6, 12, and 24 h. In addition, the time to first rescue analgesic was significantly longer in R group (429 ± 54 min) than that in K group (272 ± 34 min), but compared to both groups, it was longer in C group (52 ± 7 min). In K group, the recovery time was longer with higher sedation score in comparison to the other two groups. CONCLUSIONS: Single retrobulbar injection and low-dose ketamine infusion are safe and effective when used as adjuvants to general anesthesia, but retrobulbar block provides better control of postoperative pain with prolonged time to first rescue analgesic and reduced analgesic consumption.

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.

A preoperative bupivacaine retrobulbar block offers superior antinociception compared with an intraoperative splash block in dogs undergoing enucleation.

PURPOSE: Investigate nociception differences in dogs undergoing enucleation administered bupivacaine either via preoperative retrobulbar block (pRB) or intraoperative splash block (iSB). METHODS: Prospective, randomized, double-masked, clinical comparison study. Dogs undergoing unilateral enucleation were randomized to two groups: one received bupivacaine pRB and saline iSB of the same volume, and the other received saline pRB and bupivacaine iSB. The following intraoperative parameters were recorded: heart rate (HR), respiratory rate (RR), end-tidal CO2 (EtCO2 ); systolic, mean, and diastolic arterial blood pressure (SAP, MAP, and DAP respectively); inspired end-tidal isoflurane concentration (EtISOIns), and expired end-tidal isoflurane concentration (EtISOExp). Pain scores were recorded pre- and postoperatively. Analgesic rescue was documented. Surgical hemorrhage and postoperative bruising and swelling were graded subjectively by the surgeon (HDW) and study coordinator (AEZ). RESULTS: A significant (P = .0399) increase from baseline in overall mean heart rate was recorded in iSB bupivacaine patients (n = 11) compared with pRB bupivacaine patients (n = 11), with no significant differences in other intraoperative physiologic parameters, or pain scores. More analgesic rescue events occurred in iSB bupivacaine patients compared to pRB bupivacaine patients. A near-significant increase in intraoperative bleeding (P = .0519), and a significant increase in bruising (P = .0382) and swelling (P = .0223) was noted in the iSB bupivacaine group. CONCLUSIONS: Preoperative retrobulbar block bupivacaine is more effective than an iSB bupivacaine at controlling both intraoperative and postoperative nociception in dogs undergoing enucleation. Additionally, iSB causes more postoperative bruising and swelling and may be associated with increased intraoperative hemorrhage.

Contralateral amaurosis after a retrobulbar block.

PURPOSE: To describe and discuss the workup and management of a rare complication of retrobulbar anesthesia, as well as CT and MRI findings of this complication. OBSERVATIONS: The patient underwent uncomplicated pars plana vitrectomy with membrane peel for epiretinal membrane removal. Shortly after completion of surgery, the patient noted that he could not see out of his non-operated eye. Visual acuity was bare hand motion, and physical exam revealed a dilated, non-reactive pupil with normal, well-perfused retina. Imaging revealed an air bubble in the optic nerve of the operated eye, suggesting penetration of the optic nerve sheath during retrobulbar block with posterior spread of anesthetic to the contralateral optic nerve. CONCLUSIONS AND IMPORTANCE: After imaging ruled out acute intracranial pathology and confirmed the correct diagnosis, the patient was monitored until vision in the non-operated eye returned to baseline. Excellent visual acuity was attained in the operated eye. Central spread of anesthetic after retrobulbar anesthesia is a rare but potentially life-threatening complication that must be promptly diagnosed and addressed.

Brainstem Anaesthesia after Retrobulbar Block.

Regional anaesthesia techniques in ophthalmology are usually utilized for day case surgery. During various procedures, profound akinesia of the eye and anaesthesia of the surgical site are required, both of which are achieved with retrobulbar block. Due to the anatomy of the eye, life-threatening complications are possible. An 82-year-old female with secondary post-herpetic uveitic glaucoma of the right eye presented at the Department of Ophthalmology for an elective trans-scleral laser cyclophotocoagulation. She was given a retrobulbar block to the right eye with 2 mL of 0.5% levobupivacaine and 2 mL of 2% lidocaine. The procedure was technically performed without any issues. 2-3 minutes after the injection she became lethargic and 5 minutes later she lost consciousness and developed severe hypotension with bradycardia and respiratory arrest. She was successfully intubated and resuscitated, using mechanical ventilation, vasoactive medications, fluid therapy and intravenous lipid emulsion. There are three mechanisms for local anaesthetic (LA) to reach the central nervous system after a retrobulbar block: systemic absorption of LA, direct intra-arterial injection and retrograde flow into the cerebral circulation, and injecting LA into the subdural space via puncturing the dural optic nerve sheath, the latter being most common. The clinical picture of our patient was very consistent with subdural anaesthesia after exposure of the pons, midbrain and cranial nerves to LA, i.e. brainstem anaesthesia. Following appropriate life support measures taken in our case, there was a successful outcome. To minimize the chance for brainstem anaesthesia after retrobulbar block, we recommend low volume with low concentration of LA and block performance by an experienced ophthalmologist or anaesthesiologist with proper technique. Patients receiving retrobulbar anaesthesia should be carefully monitored at least 20 minutes after the block. Life support equipment should be available before performing retrobulbar block.

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.

Amaurosis and contralateral cranial nerve pairs III and VI paralysis after peribulbar block - Case report / Amaurose e paralisia do III e do VI pares cranianos contralaterais após bloqueio peribulbar - relato de caso

Abstract Background and objectives: Peribulbar anesthesia has emerged as a safer option compared with intraconal retrobulbar block. Still, peribulbar anesthesia may not be considered without risk. Numerous complications have been described when performing this technique. This report aims to describe a rare case of amaurosis and contralateral paralysis while attempting to perform a peribulbar anesthesia. Case report: Male patient, 75-year old, physical status ASA II, undergoing cataract surgery by phacoemulsification with intraocular lens implantation. Sedated with fentanyl and midazolam and subjected to peribulbar anesthesia. There were no complications during surgery. After finishing the procedure, the patient reported lack of vision in the contralateral eye. Akinesia of the muscles innervated by the cranial nerve pairs III and VI, ptosis, and medium-sized pupils unresponsive to light stimulus were observed. Four hours after anesthesia, complete recovery of vision and eyelid and eyeball movements was seen in the non-operated eye. Conclusions: During peribulbar anesthesia, structures located in the intraconal space can be accidentally hit leading to complications such as described in the above report. Following the technical guidelines and using appropriate size needles may reduce the risk of such complication, but not completely.

Resumo Justificativa e objetivos: A anestesia peribulbar surgiu como uma opção mais segura quando comparada com o bloqueio retrobulbar intraconal. Ainda assim, a anestesia peribulbar não pode ser considerada isenta de riscos. Inúmeras complicações foram descritas quando da aplicação dessa técnica. O presente relato tem como objetivo descrever um caso raro caracterizado por amaurose e paralisia contralaterais quando da tentativa de se fazer a anestesia peribulbar. Relato de caso: Paciente masculino, 75 anos, estado físico ASA II, submetido à facectomia por facoemulsificação com implante de lente intraocular. Sedado com fentanil e midazolam e submetido a APB. Não houve intercorrências durante a cirurgia. Após o término do procedimento o paciente relatou ausência de visão no olho contralateral. Foram observadas acinesia da musculatura inervada pelo III e VI pares cranianos, ptose palpebral e pupilas de tamanho médio, não responsivas ao estímulo luminoso. Após quatro horas da anestesia, houve recuperação completa da visão, da movimentação das pálpebras e do globo ocular não operado. Conclusões: Durante a APB, estruturas localizadas no espaço intraconal podem ser atingidas acidentalmente levando a complicações como a descrita no relato acima. O respeito às diretrizes técnicas e o uso de agulhas com o tamanho adequado podem reduzir o risco de tal complicação, mas não de forma completa.

Evaluation of ocular perforation during retrobulbar block using high-resolution spectral domain-optical coherence tomography and optical coherence tomography angiography.

INTRODUCTION: This article reports a case of ocular perforation during a retrobulbar block in a patient who underwent scleral buckle for retinal detachment. METHODS: Sterile air was immediately injected into the vitreous cavity to restore intraocular pressure and the scleral buckle operation was quickly finished. One week later, a laser retinopexy was performed on the two retinal holes that were outside the foveal area. After 6 months, spectral domain-optical coherence tomography and optical coherence tomography angiography were performed on the perforated wall centered on the exit hole area. RESULTS: The visual acuity was maintained 20/20 and the retina was totally attached. Spectral domain-optical coherence tomography showed a localized interruption of inner retina, retinal pigment epithelium, and choroid, with a higher posterior reflectivity in correspondence with the sclera. Optical coherence tomography angiography was able to detect atrophic alterations in the choroidal slab with a good visualization of large and rarefied choroidal vessels due to lack of retinal pigment epithelium and choriocapillaris. CONCLUSION: When ocular perforation by a needle is outside the foveal area and when there is an early awareness of the perforation, the complications may be avoided, and we could observe a good final visual acuity result. Furthermore, using spectral domain-optical coherence tomography and optical coherence tomography angiography, we could observe the perforated eyeball wall and study the effects of a 25-gauge needle perforation in the retinal and choroidal blood stream.

[Amaurosis and contralateral cranial nerve pairs III and VI paralysis after peribulbar block - case report]. / Amaurose e paralisia do III e do VI pares cranianos contralaterais após bloqueio peribulbar ­ relato de caso.

BACKGROUND AND OBJECTIVES: Peribulbar anesthesia has emerged as a safer option compared with intraconal retrobulbar block. Still, peribulbar anesthesia may not be considered without risk. Numerous complications have been described when performing this technique. This report aims to describe a rare case of amaurosis and contralateral paralysis while attempting to perform a peribulbar anesthesia. CASE REPORT: Male patient, 75-year old, physical status ASA II, undergoing cataract surgery by phacoemulsification with intraocular lens implantation. Sedated with fentanyl and midazolam and subjected to peribulbar anesthesia. There were no complications during surgery. After finishing the procedure, the patient reported lack of vision in the contralateral eye. Akinesia of the muscles innervated by the cranial nerve pairs III and VI, ptosis, and medium-sized pupils unresponsive to light stimulus were observed. Four hours after anesthesia, complete recovery of vision and eyelid and eyeball movements was seen in the non-operated eye. CONCLUSIONS: During peribulbar anesthesia, structures located in the intraconal space can be accidentally hit leading to complications such as described in the above report. Following the technical guidelines and using appropriate size needles may reduce the risk of such complication, but not completely.

Profound vascular stasis of retina and optic nerve following retrobulbar anesthesia.

INTRODUCTION: We aim to describe a mechanism of vision loss following vitrectomy surgery with retrobulbar block (RBB) associated with severe vascular stasis of the optic nerve and macula in order to improve safety of local anesthesia for ophthalmic surgery. CASE PRESENTATION: We report three cases of patients who underwent pars plana vitrectomy (PPV) with retrobulbar anesthesia with no retrobulbar hemorrhage or elevated intraocular pressure (IOP). At the beginning, in each case, hypoperfusion of optic nerve and macula was noted. In the case of one patient with significant vasculopathic risk factors, the vascular stasis was severe, while in the other two cases, it was mild-to-moderate. In all cases, the perfusion of posterior pole began to improve almost immediately following the start of PPV. Because the IOP was not elevated and no retrobulbar hemorrhage was present, this suggested a compartment syndrome in the intraconal space. The patient with severe vascular stasis developed finger-counting vision but had normal postoperative angiogram findings and unrevealing cardiovascular workup. In the other two milder cases, the occurrence of ischemia was not visually significant. CONCLUSION: Intraoperative ischemia should be considered in all cases of unexplained vision loss after ophthalmic surgery using RBB. Attention to vasculopathic risk factors and intra-operative hemodynamic parameters, in addition to the use of parabulbar block, may avoid this complication and permanent vision loss.

DEVELOPMENT OF RETROBULBAR AND AURICULOPALPEBRAL NERVE BLOCKS IN CALIFORNIA SEA LIONS (ZALOPHUS CALIFORNIANUS).

Eye lesions are commonly observed in pinnipeds. Clinical assessment is challenging because animals are often blepharospastic and under inhalant anesthesia the globe rotates ventrally, making observation difficult. Retrobulbar and auriculopalpebral nerve block techniques have been developed in other species to alleviate these difficulties and allow for a more thorough ophthalmic exam. Ocular nerve block techniques were developed for California sea lions (CSLs) (Zalophus californianus) using lidocaine hydrochloride 2%. To develop the retrobulbar block, a variety of needle sizes, anatomic approaches, and volumes of methylene blue were injected into the orbits of 10 CSL cadavers. An optimal technique, based on desired distribution of methylene blue dye into periocular muscles and tissues, was determined to be a two-point (ventrolateral and ventromedial) transpalpebral injection with a 20-ga, 1 1/2-inch needle. This technique was then tested using lidocaine on 26 anesthetized animals prior to euthanasia, and on one case with clinical ocular disease. A dose of 4 mg/kg of lidocaine was considered ideal, with positive results and minimal complications. The retrobulbar block had a 76.9% rate of success (using 4 mg/kg of lidocaine), which was defined as the globe returning at least halfway to its central orientation with mydriasis. No systemic adverse effects were noted with this technique. The auriculopalpebral nerve block was also adapted for CSLs from techniques described in dogs, cattle, and horses. Lidocaine was injected (2-3 ml) by subcutaneous infiltration lateral to the orbital rim, where the auriculopalpebral nerve branch courses over the zygomatic arch. This block was used in five blepharospastic animals that were anesthetized for ophthalmic examinations. The auriculopalpebral nerve block was successful in 60% of the cases, which was defined as reduction or elimination of blepharospasm for up to 3 hr. Success appeared to be dependent more on the location of injection rather than on the dose administered.