Image-guided orbital surgery: a preclinical validation study using a high-resolution physical model.

OBJECTIVE: Preclinical validation study to assess the feasibility and accuracy of electromagnetic image-guided systems (EM-IGS) in orbital surgery using high-fidelity physical orbital anatomy simulators. METHODS: EM-IGS platform, clinical software, navigation instruments and reference system (StealthStation S8, Medtronic) were evaluated in a mock operating theatre at the Royal Victoria Eye and Ear Hospital, a tertiary academic hospital in Dublin, Ireland. Five high-resolution 3D-printed model skulls were created using CT scans of five anonymised patients with an orbital tumour that previously had a successful orbital biopsy or excision. The ability of ophthalmic surgeons to achieve satisfactory system registration in each model was assessed. Subsequently, navigational accuracy was recorded using defined anatomical landmarks as ground truth. Qualitative feedback on the system was also attained. RESULTS: Three independent surgeons participated in the study, one junior trainee, one fellow and one consultant. Across models, more senior participants were able to achieve a smaller system-generated registration error in a fewer number of attempts. When assessing navigational accuracy, submillimetre accuracy was achieved for the majority of points (16 landmarks per model, per participant). Qualitative surgeon feedback suggested acceptability of the technology, although interference from mobile phones near the operative field was noted. CONCLUSION: This study suggests the feasibility and accuracy of EM-IGS in a preclinical validation study for orbital surgery using patient specific 3D-printed skulls. This preclinical study provides the foundation for clinical studies to explore the safety and effectiveness of this technology.

Twelve-month analysis of emergency argon laser retinopexy in an Irish tertiary hospital.

BACKGROUND: Retinal tears occur as a result of traction at sites of retinal and vitreous adhesion-this allows retrohyaloid fluid into the subretinal space. Prompt management is required to prevent progression to rhegmatogenous retinal detachment (RRD). AIMS: To identify the post-procedural outcomes following treatment of retinal tears with laser retinopexy in an emergency setting. METHODS: Retrospective review of all patients who underwent emergency slit-lamp laser retinopexy between January and December 2021 in Cork University Hospital, an Irish tertiary referral centre. RESULTS: A total of 87 patients were identified-mean age of 60 ± 12 years and 54% female. Follow-up ranged from 1 week to 11 months. Pre-disposing risk factors were identified-myopia (37%), recent trauma (2%), and RRD family history (5%). All patients had slit-lamp mounted laser-retinopexy performed in the eye-casualty. 63 patients (72%) had a superior break, 66 patients (76%) had a horse-shoe retinal tear, and 21 patients (24%) had a retinal hole. Associated findings included lattice degeneration (26%), sub-retinal fluid (55%), and vitreous haemorrhage (33%). Fourteen patients (16%) required multiple slit-lamp laser retinopexies while 18 patients (21%) required intervention by a vitreo-retinal surgeon including indirect-laser retinopexy (3%), cryotherapy (11%), and pars-plana vitrectomy (6%). At the most recent follow-up, all the patients had anatomically attached retinas. CONCLUSION: A notable proportion of patients (21%) undergoing emergency laser retinopexy required further intervention. Patients with anteriorly located retinal tears would benefit from an early discussion with a vitreo-retinal surgeon. Departmental training in laser retinopexy and retinal tear management is recommended as part of ongoing quality improvement.

p53 and Myofibroblast Apoptosis in Organ Fibrosis.

Organ fibrosis represents a dysregulated, maladaptive wound repair response that results in progressive disruption of normal tissue architecture leading to detrimental deterioration in physiological function, and significant morbidity/mortality. Fibrosis is thought to contribute to nearly 50% of all deaths in the Western world with current treatment modalities effective in slowing disease progression but not effective in restoring organ function or reversing fibrotic changes. When physiological wound repair is complete, myofibroblasts are programmed to undergo cell death and self-clearance, however, in fibrosis there is a characteristic absence of myofibroblast apoptosis. It has been shown that in fibrosis, myofibroblasts adopt an apoptotic-resistant, highly proliferative phenotype leading to persistent myofibroblast activation and perpetuation of the fibrotic disease process. Recently, this pathological adaptation has been linked to dysregulated expression of tumour suppressor gene p53. In this review, we discuss p53 dysregulation and apoptotic failure in myofibroblasts and demonstrate its consistent link to fibrotic disease development in all types of organ fibrosis. An enhanced understanding of the role of p53 dysregulation and myofibroblast apoptosis may aid in future novel therapeutic and/or diagnostic strategies in organ fibrosis.

Beware the Retrobulbar Optic Neuritis Diagnosis.

A 48-year-old gentleman presented to the ophthalmology department with progressive monocular vision loss, a relative afferent-pupillary defect, decreased color perception, headache, proptosis, and retro-orbital pain. This particular patient's demographics and disease course did not suggest a "typical" retro-bulbar optic neuritis and highlights the importance of avoiding presumptive steroid treatment in such "atypical" cases. Further investigations revealed a compressive optic neuropathy secondary to an orbital tumor (B-cell non-Hodgkin's lymphoma) and were subsequently treated by a multi-disciplinary approach. Early detection and commencement of treatment is a crucial determining factor in orbital lymphoma prognosis and is therefore an important differential diagnosis for an ophthalmologist to consider when evaluating patients with "atypical" optic neuropathies.

Pheochromocytoma due to a novel SDHD variant presenting as unilateral visual loss.

SUMMARY: A 53-year-old female presented to a tertiary ophthalmology referral centre complaining of unilateral painless loss of vision. Subsequent assessment revealed malignant hypertension causing right-sided cystoid macular oedema. During the course of secondary hypertension workup, she was diagnosed with a 7.8 cm phaeochromocytoma which was resected. Testing for a panel of all predisposing phaeochromocytoma-causing variants using next-generation sequencing resulted in the diagnosis of a novel SDHD variant. LEARNING POINTS: Screening for secondary causes of hypertension is indicated when there is evidence of hypertension-mediated end-organ damage (1). Testing for a predisposing variant should be considered in all patients with phaeochromocytoma or paraganglioma due to the high heritability rate and prevalence of somatic variants (2, 3, 4). Novel variants are commonly uncovered in the Succinate Dehydrogenase (SDH) subunit; proving pathogenicity is a complex, time-consuming process and one challenge of next-generation sequencing (3). SDHB immunohistochemistry as a tool for demonstrating pathogenicity is associated with reduced sensitivity when assessing SDHD variants (5, 6).