Comparative efficacy of low-volume retrobulbar anesthesia using three commercial local anesthetics in adult horses

OBJECTIVE

To compare the efficacy of low-volume (5-mL) locoregional retrobulbar anesthesia ("retrobulbar block") by use of 3 commercial local anesthetic formulations.

ANIMALS

8 healthy adult mares.

METHODS

A block-randomized, masked, controlled design was used. A single ultrasound-guided retrobulbar block was performed with 2% lidocaine, 2% mepivacaine, or 0.5% bupivacaine (n = 5 eyes/group). Contralateral eyes served as untreated controls. End points performed at baseline and time intervals up to 24 hours postblock included the following: assessment of neurophthalmic reflexes/responses, intraocular pressure, and vertical pupil diameter measurement, corneal and periocular esthesiometry, and observation for adverse effects.

RESULTS

Low-volume block did not result in increased intraocular pressure or other adverse effects at any time point in any treatment group. Statistically significant corneal anesthesia (P < .001) was observed 1 minute after block in all groups, persisting through 4 hours after lidocaine or mepivacaine block and through 24 hours after bupivacaine block. Clinically significant periocular anesthesia was not observed in any group. Significant vertical pupil diameter increase (P < .05) was observed for up to 4 hours after lidocaine or mepivacaine block and 6 hours after bupivacaine block.

CLINICAL RELEVANCE

Low-volume retrobulbar block with any of the 3 local anesthetic drugs evaluated was not associated with adverse effects. In terms of efficacy, mepivacaine block showed no clinical advantage over lidocaine block. However, bupivacaine block induced comparatively rapid and sustained corneal anesthesia. In comparison to published findings using a larger injection volume, low-volume retrobulbar block with lidocaine produced clinically comparable corneal anesthesia. However, periocular soft tissue anesthesia was not achieved with any local anesthetic drug at low volume.

Optic nerve meningioma and cloacal adenocarcinoma in a Humboldt penguin

A 26-y-old, male, captive Humboldt penguin (Spheniscus humboldti) was euthanized following a 3.5-mo history of weakened elimination mechanics, recurrent tenesmus, intermittent hemorrhagic droppings, and a cloacal mass. Blepharospasm, of unknown cause, of the right eye was present for ~3 mo before euthanasia. Autopsy revealed a cloacal adenocarcinoma with localized coelomic carcinomatosis and distant metastases to the liver and lungs. On histopathology, a 2.6 × 1.2 × 0.5-mm, well-demarcated mass was found surrounding the right optic nerve, expanding the subdural space and wrapping the leptomeninges. The mass was composed of neoplastic spindle-to-polygonal cells consistent with a meningioma, meningothelial subtype. No evidence of neoplasia was found in the optic chiasm or brain, indicating a primary retrobulbar meningioma. Immunohistochemistry for cytokeratin AE1/AE3, vimentin, and S100 revealed robust and consistent immunoreactivity to vimentin, and weak and variable immunoreactivity to cytokeratin and S100, supporting the diagnosis. Meningiomas have been described only rarely in avian species, and we found no reports of optic nerve meningiomas in any avian species to date. The optic nerve meningioma in this case was considered a clinically incidental finding.

Effect of dexmedetomidine added to retrobulbar blockade with lignocaine and bupivacaine in dogs undergoing enucleation surgery

OBJECTIVE

To investigate the effect of the addition of dexmedetomidine (BLD) to retrobulbar blockade with combined lignocaine and bupivacaine on nociception.

ANIMALS

A total of 17 eyes from 15 dogs.

METHODS

Prospective, randomized, masked clinical comparison study. Dogs undergoing unilateral enucleation were randomly assigned into two groups; a retrobulbar administration of lignocaine and bupivacaine in a 1:2 volume ratio combined with either BLD or 0.9% saline (BLS). The total volume of the intraconal injection was calculated at 0.1 mL/cm cranial length. Intraoperative parameters were recorded: heart rate (HR), respiratory rate (RR), end-tidal CO2 (EtCO2 ) arterial blood pressure (BP), and inspired isoflurane concentration (ISOinsp). Pain scores, heart rate and RR were recorded postoperatively.

RESULTS

Dogs receiving BLD (n = 8) had significantly lower intraoperative RR (p = 0.007), and significantly lower ISOinsp (p = 0.037) than dogs in the BLS group (n = 9). Postoperatively heart rate was significantly lower in the BLD group at 1 min (p = 0.025) and 1 h (p = 0.022). There were no other significant differences in intraoperative or postoperative parameters, or in postoperative pain scores (p = 0.354). Dogs receiving BLD had a higher rate of anesthetic events of bradycardia and hypertension (p = 0.027). Analgesic rescue was not needed in either group.

CONCLUSIONS

The addition of BLD to retrobulbar anesthesia did not result in a detectable difference in pain scores relative to blockade with lignocaine and bupivacaine alone. Dogs receiving retrobulbar BLD had a significantly lower intraoperative RR and isoflurane requirement and an increased incidence of intraoperative bradycardia and hypertension.

Transcutaneous retrobulbar amphotericin B for rhino-orbital-cerebral mucormycosis: a multi-center retrospective comparative study

PURPOSE

To assess whether transcutaneous retrobulbar amphotericin B injections (TRAMB) reduce exenteration rate without increasing mortality in rhino-orbital-cerebral mucormycosis (ROCM).

METHODS

In this retrospective case-control study, 46 patients (51 eyes) with biopsy-proven ROCM were evaluated at 9 tertiary care institutions from 1998 to 2021. Patients were stratified by radiographic evidence of local orbital versus extensive involvement at presentation. Extensive involvement was defined by MRI or CT evidence of abnormal or loss of contrast enhancement of the orbital apex with or without cavernous sinus, bilateral orbital, or intracranial extension. Cases (+TRAMB) received TRAMB as adjunctive therapy while controls (-TRAMB) did not. Patient survival, globe survival, and vision/motility loss were compared between +TRAMB and -TRAMB groups. A generalized linear mixed effects model including demographic and clinical covariates was used to evaluate the impact of TRAMB on orbital exenteration and disease-specific mortality.

RESULTS

Among eyes with local orbital involvement, exenteration was significantly lower in the +TRAMB group (1/8) versus -TRAMB (8/14) (p = 0.04). No significant difference in mortality was observed between the ±TRAMB groups. Among eyes with extensive involvement, there was no significant difference in exenteration or mortality rates between the ±TRAMB groups. Across all eyes, the number of TRAMB injections correlated with a statistically significant decreased rate of exenteration (p = 0.048); there was no correlation with mortality.

CONCLUSIONS

Patients with ROCM with local orbital involvement treated with adjunctive TRAMB demonstrated a lower exenteration rate and no increased risk of mortality. For extensive involvement, adjunctive TRAMB does not improve or worsen these outcomes.

Comparison of a blind and an ultrasound-guided technique for Retrobulbar anesthesia in dogs undergoing unilateral subconjunctival enucleation

OBJECTIVE

This study compared the quality of retrobulbar anesthesia using a blind inferior-temporal palpebral approach (ITP) with an ultrasound-guided supratemporal (ST) technique in dogs undergoing unilateral enucleation.

ANIMAL STUDIED

Twenty-one client-owned dogs were undergoing enucleation.

PROCEDURES

Dogs were randomly assigned to receive ITP (n = 10) or ST (n = 11) with 0.5% ropivacaine at 0.1 mL/cm of neurocranial length. The anesthetist was blinded to the technique. Intraoperative data included cardiopulmonary variables, inhalant anesthetics requirement, and requirement for rescue analgesia (intravenous fentanyl 2.5 mcg/kg). Postoperative data included pain scores, sedation scores, and need for intravenous hydromorphone (0.05 mg/kg). Treatments were compared using Wilcoxon's rank sum test or Fisher's exact test as appropriate. Comparison of variables over time were tested using a mixed effect linear model on rank. Significance was set at p = 0.05.

RESULTS

Intraoperative cardiopulmonary variables and inhalant requirements were not different between groups. Dogs receiving ITP required median (interquartile range, IQR) 1.25 (0, 2.5) mcg/kg intraoperative fentanyl while those receiving ST required none (p < 0.01). Intraoperative fentanyl was required in 5/10 and 0/11 of dogs in the ITP and ST groups, respectively (p = 0.01). Postoperative analgesia requirements were not significantly different between groups; 2/10 and 1/10 dogs in the ITP and ST groups, respectively. Sedation score negatively affected pain score (p < 0.01).

CONCLUSIONS

The ultrasound-guided ST technique was more effective at decreasing intraoperative opioid requirements than the blind ITP approach in dogs undergoing unilateral enucleation.

Long-term systemic antibiotics and surgical treatment can be an effective treatment option for retrobulbar abscesses in rabbits (Oryctolagus cuniculus): 21 cases (2011-2022)

OBJECTIVE

To characterize the epidemiologic features of rabbits with retrobulbar abscesses, including the clinical signs, diagnosis, treatment, and outcome.

ANIMALS

21 client-owned rabbits.

METHODS

The medical record database of a veterinary teaching hospital was searched from 2011 to 2022 for records of rabbits diagnosed with retrobulbar abscesses by CT. Data reviewed included age, breed, presenting complaint, association with an odontogenic infection, aerobic and anaerobic culture results, treatment, and outcome.

RESULTS

The primary presenting complaint was exophthalmos (19/21 [90%]). Most cases (15/21 [71%]) were associated with an odontogenic infection. Dental disease, not associated with a retrobulbar abscess (14/21 [67%]), was a common comorbidity on CT. The most common aerobic and anaerobic isolates were Streptococcus intermedius (5/12 [42%]) and Fusobacterium nucleatum (2/12 [17%]), respectively. Surgical treatment combined with long-term systemic antibiotic therapy was performed in 9 of 21 (43%) cases. It included intraoral tooth extraction (4/9 [44%]) versus extraoral peribulbar abscess lancing with either abscess packing with antibiotic-soaked gauze (3/9 [33%]) or surgical abscess debridement (2/9 [22%]). Resolution of the clinical signs with no recurrence for at least 6 months occurred in 7 of 9 (78%) surgically treated cases. Medical treatment with long-term systemic antibiotic therapy was performed in 4 of 21 (19%) cases, and 3 of 4 (75%) resolved. Due to poor prognosis or financial concerns, euthanasia was performed or recommended in 8 of 21 (38%) cases.

CLINICAL RELEVANCE

On the basis of the data from this study, retrobulbar abscesses in rabbits carry a guarded prognosis. When intraoral and extraoral surgical treatment options combined with systemic antibiotic therapy were used, it resolved clinical disease in most cases.

Retrobulbar Blood Flow Parameters in Patients With Anisometropic Amblyopia

Introduction We aim to compare retrobulbar blood flow parameters between the amblyopic eye and the fellow eye in patients with anisometropic amblyopia. Methods Peak systolic velocity (PSV) and end-diastolic velocity (EDV) of the ophthalmic artery (OA), central retinal artery (CRA), and posterior ciliary artery (PCA) were measured by color Doppler imaging (CDI), and the resistivity index (RI) and pulsatility index (PI) were calculated in 62 patients aged 12-40 years with anisometropic amblyopia. Results The mean PSV values of OA, CRA, and PCA in amblyopic and fellow eyes were 30.38 ± 10.34, 8.45 ± 2.27, and 8.03 ± 2.77, and 33.73 ± 14.46, 8.35 ± 2.05, and 8.81 ± 2.77, respectively. The mean EDV values of OA, CRA, and PCA in amblyopic and fellow eyes were 6.86 ± 2.64, 1.47 ± 1.59, and 1.94 ± 2.03, and 8.57 ± 4.30, 1.80 ± 1.73, and 2.32 ± 1.20, respectively. The mean RI values of OA, CRA, and PCA in amblyopic and fellow eyes were 0.77 ± 0.10, 0.85 ± 0.14, and 0.78 ± 0.15, and 0.75 ± 0.07, 0.79 ± 0.20, and 0.74 ± 0.13, respectively. OA-PSV and OA-EDV values were significantly lower in the amblyopic eye than in the healthy eye (p < 0.05). OA-RI values were significantly higher (p < 0.05) in the amblyopic eye than in the healthy eye. Conclusions Considering the decrease in PSV and EDV and the increase in RI, which are the blood flow parameters of the amblyopic eye, our study may provide guidance to focus on increasing blood flow in the treatment of amblyopia.

Retrobulbar respiratory epithelial orbital cyst in a dog: A case report

A 10-month-old female, neutered French Bulldog presented with a history of unilateral right-sided intermittent conjunctivitis and exophthalmos. The patient suffered blunt force trauma to the right eye after a tennis ball impact approximately five months prior to presentation. Examination identified the patient was visual with exophthalmos, lateral strabismus, conjunctival hyperaemia, episcleral congestion, and papilloedema. Magnetic resonance imaging and ultrasonography identified an approximately two centimeter diameter fluid-filled structure directly posterior to the globe leading to displacement of the optic nerve and distortion of the posterior globe wall. Centesis of the lesion demonstrated neutrophilic and macrophagic inflammation with evidence of prior hemorrhage. Within four weeks, the structure had re-filled to its original size and was subsequently excised in its entirety, via a lateral orbitotomy. Histopathologic findings indicated a non-keratinising orbital cyst, the lining of which was consistent with a respiratory epithelial cyst. Recurrence had not occurred seven months' post-surgery. To the author's knowledge, previous reports of retrobulbar respiratory epithelial cysts have not been documented in animals.

COMPARISON OF RETROBULBAR, SUB-TENON ANESTHESIA AND MEDIAL CANTHUS EPISCLERAL ANESTHESIA FOR 25-GAUGE POSTERIOR VITRECTOMY

PURPOSE

The aim of the study is to compare the efficacy, safety, and globe akinesia between retrobulbar anesthesia, sub-Tenon anesthesia, and medial canthus episcleral anesthesia for 25-gauge posterior vitrectomy.

METHODS

A total of 340 25-gauge vitrectomy data sheets were retrospectively collected between November 2017 and June 2019. Ninety patients were included in the study. These patients were matched by sex and age to receive retrobulbar anesthesia (group 1, n = 30), sub-Tenon anesthesia (group 2, n = 30), and medial canthus episcleral anesthesia (group 3, n = 30). Globe akinesia was recorded after the injection of anesthetic at 2, 5, and 10 minute time intervals. Patients were asked to rate the pain during administration of anesthesia, during surgery, and postoperatively using the visual analog pain scale.

RESULTS

For a perfect block, at 10 minutes, retrobulbar outperformed both sub-Tenon and medial canthus episcleral anesthesia which seemed quite similar. During administration, the three techniques did not show statistically different effects on pain. Regarding perioperative pain, retrobulbar outperformed medial canthus episcleral anesthesia.

CONCLUSION

All three techniques allowed for safe surgery. Retrobulbar obtained the best results, although sub-Tenon proved to be a valid alternative. Medial canthus episcleral anesthesia obtained mostly good and fair blocks and acceptable pain levels during surgery. Further studies should investigate whether optimal anesthetic efficacy can be obtained with sub-Tenon and medial canthus episcleral techniques when higher volumes are used.

Canine Retrobulbar Cellulitis and Abscessation in the Southeastern United States: A review of case management, diagnostic imaging, bacterial isolates, and susceptibility patterns

OBJECTIVE

To describe common bacterial organisms cultured from retrobulbar cellulitis and abscess lesions, in vitro susceptibility patterns, common diagnostic techniques utilized, etiologies encountered, and prevalence of blindness.

ANIMALS STUDIED

Thirty-eight dogs diagnosed with retrobulbar cellulitis or abscessation from 2007 to 2017.

PROCEDURE

For cases of orbital cellulitis or abscess, signalment, orbital imaging, cytology, histopathology, bacterial culture and susceptibility testing, presence of vision at the initial examination and resolution, and presumed cellulitis/abscess etiology were recorded.

RESULTS

Most cases were medically (78.9%) versus surgically managed (18.4%). Most common form of orbital imaging was computed tomography (48.5%) followed by ocular ultrasound (18.2%). Fifteen of eighteen cultures (83.3%) showed growth of aerobic bacterial organisms, anaerobic bacterial organisms, or both. Most common aerobic bacteria were gram-negative bacilli (40.0%) followed by Corynebacterium sp. (26.7%) and α-hemolytic Streptococci sp. (26.7%) but Micrococcus and Bacillus spp. were also identified. Most common anaerobic bacteria were gram-negative bacilli (40.0%). Antibiotics with highest susceptibility patterns included gentamicin, followed equally by amoxicillin/clavulanic acid, cephalothin, chloramphenicol, and imipenem. No bacteria were susceptible to cefovecin. Six cases presented with vision loss due to retrobulbar disease (15.8%). Idiopathic (50%) disease and tooth root abscessation (23.7%) were most commonly diagnosed cause of orbital disease.

CONCLUSION

Retrobulbar cellulitis/abscess is a serious and vision-threatening process, which can be effectively managed by broad-spectrum antibiotics such as gentamicin or amoxicillin/clavulanic acid, but not cefovecin. This study identified three organisms that have not been previously reported to be associated with orbital cellulitis (Corynebacterium sp., Bacillus sp. and Micrococcus sp.).

Retrobulbar lidocaine injection via the supraorbital fossa is safe in adult horses but produces regionally variable periocular anaesthesia

BACKGROUND

Injection techniques for retrobulbar anaesthesia are published in horses, but neither safety nor anaesthetic efficacy and duration have been evaluated objectively in vivo.

OBJECTIVE

To characterise the safety and efficacy of one published technique for retrobulbar anaesthesia.

STUDY DESIGN

Randomised, controlled descriptive experiment.

METHODS

Unilateral retrobulbar injection with 10 mL lidocaine (2%) was performed in eight sedated adult mares. Contralateral eyes served as untreated controls. Neurophthalmic parameters, intraocular pressure (IOP), and corneal and periocular sensation were measured awake, post-sedation and at periodic time points for 24 hours following injection. Adverse effects were documented.

RESULTS

Injection of 10 mL lidocaine significantly increased IOP for up to 2 hours (P < .05) maximally at 30 min (mean [95% CI]: 6.0 [2.7, 9.2] mm Hg, P < .001). Six of the eight treated eyes developed mild to moderate reversible chemosis for 2 to 24 hours. One eye developed severe chemosis and superficial corneal ulceration at 24 and 48 hours following injection respectively. Corneal sensitivity significantly decreased for 6 hours (P < .05), maximally at 10 min (-44.4 [-34.6, -54.1] mm, P < .001). Periocular sensitivity (measured as increase in applied force) significantly decreased dorsally and medially for up to 2 hours (maximal at 2 hours (367.1 [238.5, 495.7] g, P < .001, and at 30 min: 345.8 [202.6, 488.9] g, P < .001) respectively). Ventral and lateral sensitivity were not effectively decreased beyond 30 min. Optic nerve function was not consistently reduced following injection.

MAIN LIMITATIONS

Investigators were not masked to the treated eye.

CONCLUSIONS

Retrobulbar injection using 10 mL lidocaine is safe in normal eyes of adult horses, but carries risk in structurally compromised or glaucomatous eyes due to transient IOP increase. Reversible chemosis commonly develops 2-4h following injection, and may be severe in some horses with risk for corneal ulceration. Corneal anaesthesia is rapid and prolonged, but all periocular regions are not consistently anaesthetised. Retrobulbar injection should be combined with other local anaesthetic injections for eyelid surgeries or enucleations.

Diagnosis and surgical management of a retrobulbar abscess causing unilateral exophthalmos in a Boer goat

A 10-year-old Boer goat wether presented for unilateral exophthalmos of 2- to 3-week duration. Ocular ultrasonography and computed tomography (CT) were utilized in the diagnosis of the patient's orbital disease and surgical planning. Exenteration was performed under the same general anesthetic event as CT. Cytology, culture, and histopathology were performed after exenteration. Cytology was consistent with a mixed bacterial infection. Culture confirmed the presence of Streptococcus ovis. Histopathology on the enucleated globe and mass revealed no evidence of tumor and confirmed intraocular extension of retrobulbar inflammation. Histopathologic diagnosis was consistent with severe chronic orbital pyogranuloma and fibrinosuppurative endophthalmitis confined to the subretinal space. The abscess recurred in the orbital space 2 weeks postoperatively; the orbit was explored. Repeat culture was consistent with S. ovis, Staphylococcus schleigeri subspecies coagulans, and Fusobacterium necrophorum. Complete resolution was obtained after drainage and lavage of the orbit. Abscess is cited as a cause of exophthalmos in small ruminants, but no individual case reports exist. Advanced imaging allowed presumptive diagnosis and surgical planning. Histopathology confirmed intraocular extension of retrobulbar disease.

Evaluation of retrobulbar circulation in type 2 diabetic patients using color Doppler imaging

Purpose:

To investigate the retrobulbar circulatory parameters in type 2 diabetes mellitus patients with color Doppler imaging (CDI) and compare the results with nondiabetic controls.

Methods:

This prospective study included 50 type 2 diabetic patients and 50 age-matched controls. Seven field stereo fundus photography was used to diagnose and classify diabetic retinopathy (DR). Diabetic patients were further divided into two: Group 1, consisted of patients with no DR, mild and moderate non-proliferative DR (n = 36); Group 2, severe nonproliferative and proliferative DR (n = 14). CDI was performed using Philips iU22 xMATRIX ultrasound. The peak systolic velocity (PSV), end-diastolic velocity (EDV), resistivity index (RI) and pulsatile index (PI) of ophthalmic (OA), posterior ciliary artery (PCA), and central retinal artery (CRA) along with central retinal vein (CRV) were recorded.

Results:

RI in the ophthalmic artery was significantly higher in both DR groups than the control group (P = 0.000). Diabetic Group 1 had decreased blood flow velocity (PSV and EDV) in PCA compared to controls (P = 0.046 and P = 0.010, respectively). Group 2 DR had significantly reduced EDV and increased RI in CRA compared to Group 1 (P = 0.015). Binary logistic regression analysis revealed glycosylated hemoglobin and RI of OA to be independent risk factors of DR.

Conclusion:

Significant changes in resistivity index and flow velocities were observed in the retrobulbar vessels, especially in ophthalmic artery in diabetics compared to controls. CDI with results of increased resistance or decreased flow could be useful to predict individuals at higher risk for developing severe DR.

Retrobulbar chlorpromazine injection in a child with gliosarcoma invasion into the orbits

This paper has two main purposes: (1) to report a rare case of paediatric gliosarcoma that invaded the surrounding orbit and (2) to demonstrate chlorpromazine injection as a potential treatment option for blind, painful eye caused by tumour invasion. A 12-year-old man who presented with headaches was found to have glioblastoma multiforme and it was excised and treated with radiation and chemotherapy. Seven months later, the tumour recurred as gliosarcoma, a rare variant of glioblastoma multiforme containing distinct gliomatous and sarcomatous components. In spite of treatment, the tumour progressed and eventually invaded into the right orbit. He subsequently developed a proptotic, blind, painful eye and was treated with retrobulbar chlorpromazine injection, which provided immediate symptomatic relief.

The Impact of Common Recovery Blood Sampling Methods, in Mice (Mus Musculus), on Well-Being and Sample Quality: A Systematic Review

Blood sampling is often performed in laboratory mice. Sampling techniques have the potential to cause pain, distress and impact on lifetime cumulative experience. In spite of institutions commonly providing guidance to researchers on these methods, and the existence of published guidelines, no systematic evaluation of the evidence on this topic exists. A systematic search of Medline, Scopus, and Web of Science was performed, identifying 27 studies on the impact of recovery blood sample techniques on mouse welfare and sample quality. Studies were appraised for quality using the SYstematic Review Centre for Laboratory animal Experimentation (SYRCLE) risk of bias tool. In spite of an acceptable number of studies being located, few studies examined the same pairwise comparisons. Additionally, there was considerable heterogeneity in study design and outcomes, with many studies being at a high risk of bias. Consequently, results were synthesised using the Synthesis Without Meta-analysis (SWiM) reporting guidelines. Grading of Recommendations, Assessment, Development and Evaluation (GRADE) was utilised for assessment of certainty in the evidence. Due to the heterogeneity and GRADE findings, it was concluded that there was not enough high-quality evidence to make any recommendations on the optimal method of blood sampling. Future high-quality studies, with standardised outcome measures and large sample sizes, are required.

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.

Retrobulbar Lymphangioma: A Rare Case Report

We report a case of biopsy-proven retrobulbar lymphangioma in a 14-year-old girl. She presented with chief complaints of swelling in the left eye for 2 months. The patient underwent imaging evaluation and it was diagnosed as cavernous hemangioma, radiologically. However, later on, the patient underwent surgery, and the specimen was sent for histopathology which revealed it to be a lymphangioma.

Migration of retrobulbar wooden foreign body between diagnostic imaging and surgical extraction in a German shepherd dog

A 2-year-old, male castrated German shepherd dog was presented to the University of Tennessee Veterinary Medical Center (UTVMC) with periorbital swelling and conjunctival mucopurulent discharge 2 days following removal of a twig from the medial canthus by the owner. Diagnostic imaging was pursued due to the suspicion of a retrobulbar foreign body (FB). A cylindrical FB approximately 3.0 cm in length and 1.0 cm in diameter with concentric rings, suspected to be wooden material, was identified on computed tomography (CT) imaging. An attempt to remove the FB via a stab incision using ultrasound guidance was unsuccessful, and postmanipulation ultrasound confirmed the FB position was unchanged. An exploratory orbitotomy was performed, using the acquired CT images for guidance in locating the FB; however, the FB was not present at the predicted site. The CT imaging was repeated and showed that the FB had migrated rostrally approximately 3.0 cm, compared to the originally acquired study and its same location during attempted ultrasound-guided removal. A combination of CT-guided needle placement and contrast injection was then used with repeat imaging in an attempt to better localize the FB and its soft tissue tract. The dog was taken back into the operating room, and the wooden FB was successfully removed.

Ocular involvement of multicentric malignant B-cell lymphoma in a ewe. A case report

An 8.5-year-old, 98 kg female mountain sheep presented with bilateral exophthalmos with reduced retropulsion of the globes, impairing physiologic eyelid closure, sanguineous ocular discharge, as well as swelling of the eyelids and periocular skin. Bilateral vitreal hemorrhage hindering examination of the fundus was further noticed. Systemic signs included reduced general demeanour, presence of a firm mass in the left half of the mammary gland, multiple masses in the area of the vulva and a mass between the shoulder blades. Complete diagnostic work-up, i.  e. complete blood count, blood chemistry and coagulation status, fine needle aspiration of periocular swellings and incisional biopsy of the vulvar masses revealed a diagnosis of malignant B-cell lymphoma. Due to the deterioration in general demeanour and rapid progression of exophthalmos, resulting in bilateral corneal ulceration, despite symptomatic medical treatment, the ewe was humanely euthanized. Gross necropsy and histopathology of select tissue samples confirmed the diagnosis of multicentric malignant B-cell lymphoma. To the authors' knowledge, this is the first report of multicentric malignant B-cell lymphoma involving the ocular adnexa in sheep.

Idiopathic sclerosing orbital inflammation mimicking a malignant spindle cell tumor in a dog

A dog presented with a retrobulbar mass, diagnosed histopathologically as malignant spindle cell neoplasia. Emergence of analogous findings in the contralateral orbit prompted extended immunohistochemistry of the original mass and reassignment to idiopathic sclerosing orbital inflammation. Early incisional biopsy with extended immunohistochemical analysis should be considered for canine orbital tumors.

Emergency management for orbital compartment syndrome-is decompression mandatory?

Current guidelines for the urgent management of patients with orbital compartment syndrome include immediate lateral canthotomy and cantholysis, followed by surgical decompression. Medical treatment is also advocated to 'buy time' while preparing the patient for theatre. This consists of high-dose steroids, mannitol, and acetazolamide diuretics to reduce swelling and orbital pressure. It is generally recognized that late or delayed intervention is associated with poor outcomes including blindness. With early presentation, given the potential risk to sight, there is generally a low threshold for treating suspected cases. However, whether or not to treat late cases is more controversial, partly because clinicians could face accusations of medical negligence if they do nothing. The case of a patient who sustained an orbital trauma to his only seeing eye, which resulted in acute proptosis and loss of vision, is presented here. He received no treatment at all for what appeared to be an orbital compartment syndrome secondary to retrobulbar haemorrhage, but surprisingly made a full recovery of vision within 48h. In contrast to the current literature in favour of urgent treatment, this case would appear to cast some doubt over the concept of 'always' treating orbital compartment syndrome and our understanding of the condition.

Peribulbar anesthesia causing bilateral orbital hemorrhage

We report a case of bilateral orbital hemorrhage as a complication of peribulbar anesthesia in a 78 year old man. Initially, unilateral orbital hemorrhage occurred but quickly spread to the contralateral side. Neuroophthalmological assessment revealed a proptosed tense globe with normal retinovascular findings. Visual acuity was adversely affected and this was conservatively managed with no lasting ophthalmic sequela. This patient’s case was reported as it illustrates an unusual complication of bilateral spread of orbital hemorrhage secondary to peribulbar anesthesia. It highlights how early ophthalmic assessment can ensure a good visual outcome in the setting of appropriate ophthalmic monitoring. The mechanisms of orbital hemorrhage spread and appropriate management options are discussed.

Management of Orbital Diseases

Orbital diseases are common in dogs and cats and can present on emergency due to the acute onset of many of these issues. The difficulty with diagnosis and therapy of orbital disease is that the location of the problem is not readily visible. The focus of this article is on recognizing classical clinical presentations of orbital disease, which are typically exophthalmos, strabismus, enophthalmos, proptosis, or intraconal swelling. After the orbital disease is confirmed, certain characteristics such as pain on opening the mouth, acute vs. chronic swelling, and involvement of nearby structures can be helpful in determining the underlying cause. Abscesses, cellulitis, sialoceles, neoplasia (primary or secondary), foreign bodies, and immune-mediated diseases can all lead to exophthalmos, but it can be difficult to determine the cause of disease without advanced diagnostic imaging, such as ultrasound, magnetic resonance imaging, or computed tomography scan. Fine-needle aspirates and biopsies of the retrobulbar space can also be performed.

Retrobulbar optic neuropathy secondary to isolated sphenoid sinus disease

Paranasal sinus disease can cause a condition that mimics optic neuritis. Simultaneous appearance of both diseases would create etiological dilemma. We report two cases of retrobulbar optic neuropathy secondary to isolated sphenoid sinus disease. In the case of a 65-year-old female who had presented with acute loss of vision in the left eye associated with left-sided frontal headache which subsequently turned out to be caused by optic nerve compression at the orbital apex due to collection in abnormally pneumatized left lesser wing of the sphenoid. In another case, a 65-year-old lady had presented with symptoms of bilateral retrobulbar optic neuropathy which was found to be due to direct compression of optic nerves at the orbital apex secondary to metastases from breast carcinoma.

Canine orbital rhabdomyosarcoma: a report of 18 cases

PURPOSE

To describe clinical and pathological features of canine orbital rhabdomyosarcoma (COR).

METHODS

Retrospective review of patients with COR from the archives of the Comparative Ocular Pathology Laboratory of Wisconsin and the University of Wisconsin Veterinary Medical Teaching Hospital (1983-2014).

RESULTS

Eighteen cases of COR were identified, all diagnosed in an 8-year period (2006-2014). Affected dogs were typically young (range 1-8; median 2 years), and both sexes were equally represented. Common clinical signs included exophthalmos (16/18) with dorsolateral deviation of the globe (10/18) and elevation of the nictitans (12/18). Ultrasonography, performed in nine cases, revealed an orbital mass with mixed echogenicity and posterior globe indentation. Advanced imaging, performed in nine cases, demonstrated a soft tissue mass with variable contrast enhancement and lysis of the orbital bones (5/9). Histologically, all tumors were subclassified as embryonal rhabdomyosarcoma. All neoplasms demonstrated positive immunohistochemical labeling for desmin, and 14/18 were positive for skeletal muscle actin. Follow-up information was available for 15/18 cases. Older dogs, aged 6-8 years, had no clinical signs of recurrence or metastasis 8-13 months postdiagnosis (4/4). Most younger dogs (9/11), aged 1-4 years, were euthanized within 6 months (median 2.5 months) of diagnosis due to recurrence at the surgical site (5/9) and/or metastasis (5/9).

CONCLUSIONS

Canine orbital rhabdomyosarcoma is a highly malignant neoplasm in juvenile dogs, but may be amenable to surgical resection in older dogs. This duality in biologic behavior may reflect differences in tissue of origin between juvenile onset tumors and adult onset tumors.

Case of Orbital Mucosa-Associated Lymphoid Tissue Lymphoma Associated with Serous Retinal Detachment

We present a case of orbital mucosa-associated lymphoid tissue (MALT) lymphoma accompanied by a serous retinal detachment (SRD). A 44-year-old man who developed uveitis accompanied by a SRD in the right eye was referred to the Chiba National Hospital. B-mode ultrasonography and magnetic resonance imaging (MRI) showed a thickened choroidal membrane and a retrobulbar mass. Although topical steroid treatments improved the inflammation, the SRD did not improve. He was then referred to the Chiba University Hospital. Two months later, the retrobulbar mass had increased, and a partial resection biopsy combined with flow cytometry was performed. The final diagnosis was MALT lymphoma. After R-CHOP (rituximab-cyclophosphamide, doxorubicin, vincristine, and prednisolone) chemotherapy, signs of the tumour could not be detected and the SRD was reduced. We conclude that the SRD was most likely due to the infiltration of lymphoma cells and also to choroidal circulatory disturbances. Retrobulbar malignant lymphomas associated with a SRD are very rare and difficult to diagnosis without biopsy, but because early diagnosis is helpful in deciding the appropriate therapy, we recommend partial biopsy.

Retrobulbar magnetic resonance angiography using binomial off-resonant rectangular (BORR) pulse

PURPOSE

Applying a newly developed binomial off-resonant rectangular (BORR) pulse method for high resolution three-dimensional MR angiography (MRA) on retrobulbar ocular vessels, which has not been possible with routine MRA due to background fatty tissues.

METHODS

BORR pulse was implemented in a gradient echo sequence by replacing the original excitation pulse, and were optimized for robust orbital fat suppression. Several other MRA methods, with or without fat suppression, were also compared, including time-of-flight, contrast enhanced MRA, and hybrid of opposite-contrast MRA. Nine healthy subjects participated with written informed consents. To reduce eye motion, the subjects were instructed to casually stare at a projected cross during each MRA scan. Major vessels were evaluated by three independent radiologists using a 4-point scale.

RESULTS

The BORR method yielded the best MRA results for retrobulbar vessels without contrast enhancement, significantly superior than other MRA methods. BORR results had significantly higher visibility scores than all other methods for small vessels.

CONCLUSION

We have successfully revealed orbital vessels in retrobulbar space for the first time using MRA, by using the BORR pulse method. With a clear depiction of the vasculature without the need for contrast enhancement, our method has the potential to provide important diagnostic information for ocular vascular diseases.

Selection of patients and results of 25 years of topical anesthesia and adjustable suture surgery

BACKGROUND AND PURPOSE

The author has used adjustable suture techniques either in the operating room with topical anesthesia or at a later time after retrobulbar or general anesthesia for over 25 years. Careful selection of patients is essential to the success of this technique. It is the purpose of this paper to report the selection criteria used and to compare the results of the two methods utilized.

PATIENTS AND METHODS

One hundred eighty-three patients were included in this study: 123 were operated upon with topical anesthesia. For comparison, sixty patients were included who had adjustment later in the day or the next day after having retrobulbar or general anesthesia. Both horizontal and vertical strabismus cases were included.

RESULTS

Adjustable techniques done in the operating room or at a later time have both shown significant improvement in the strabismus angle following one operation in 86% of the cases. Diplopia was eliminated in 63% of patients with this complaint. (63% and 64.5% in the two groups, respectively). Seventeen of 123 patients having topical anesthesia (13.8%) required a second operation, and 8 of 60 (13.3%) of those having a later adjustment needed further surgery.

CONCLUSION

Careful selection of patients undergoing strabismus surgery allows successful topical muscle adjustment in the operating room with results similar to adjustments done following retrobulbar or general anesthesia at a later time.

Ophthalmic regional anaesthesia: A review and update

Local anaesthetic techniques are increasingly popular for ophthalmic surgery. It is now being provided mainly by anaesthesiologists and varies from an akinetic injection technique to a non-akinetic topical technique. Each technique has its own risk/benefit profile, and proven to be highly successful if performed correctly. The choice of the technique should be individualized based upon specific needs of the patient, the nature and extent of eye surgery, and the anaesthesiologist's and surgeon's preferences and skill. This review article attempts to outline the orbital anatomy, discuss the commonly used agents, current method of pre-operative preparation, available clinical techniques and their inherent complications.