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- retinal pick
- arteriovenous adventitial sheathotomy
- branch retinal vein occlusion
- transvitreal arteriovenous- crossing manipulation without vitrectomy
- optical coherence tomography
Although arteriovenous adventitial sheathotomy (AAS) has been proposed as an alternative treatment for patients with branch retinal vein occlusion (BRVO) complicated by macular haemorrhage, persistent macular oedema after grid laser photocoagulation, and macular ischaemia, the inner retinal incision may increase the risk of retinal detachment and spontaneous vitreous haemorrhage.1–3 Han et al.2 recently proposed that incomplete separation of the common adventitial sheath without lysis may achieve comparable results. Thus, we propose transvitreal limited arteriovenous crossing manipulation (LAM) without vitrectomy as an alternative to AAS.
A 70 year old man with a medical history of hypertension, presented with BRVO of 14 weeks’ duration, visual acuity of 7/200, intraretinal macular haemorrhages, macular oedema assessed by ocular coherence tomography, and capillary non-perfusion on fluorescein angiography (fig 1). After informed consent and institutional review board approval was obtained, the patient underwent LAM without vitrectomy using the 25 gauge transconjunctival standard vitrectomy system (MADLAB, Bausch & Lomb, St Louis, MO, USA). Next, the blunt, flexible extendable pick (MADLAB) was introduced into the vitreous, and, once extended, makes a slit in the internal limiting membrane approximately 1.5 mm next to the pathological arteriovenous crossing. Then, LAM was initiated by first lifting the proximal portion of the artery followed by the portion distal to the crossing. Then, the artery was lifted at the crossing site, stretching but not severing the common adventitial sheath. Visualisation of clot dislodgement and reperfusion were noted. No vitrectomy was performed and no vitreous cutter was used during the procedure. There was no evidence of posterior vitreous detachment.
At the 2 month postoperative visit, the patient’s visual acuity was 20/40. Fundus photography and fluorescein angiography revealed markedly decreased intraretinal haemorrhages and good macular perfusion, respectively. Macular thickness decreased from 512 µm to 133 µm on optical coherence tomography (fig 2). No cataract progression was noted and intraocular pressure remained stable throughout the postoperative course. The patient has remained stable for over 12 months.
Our group has previously published a case report of 25 gauge AAS with vitrectomy where improvement was noted in visual acuity, macular thickness (as measured by optical coherence tomography), and refixation (as shown by scanning laser ophthalmoscopy).4 Han et al2 postulated that incomplete separation of the common adventitial sheath may be an alternative to AAS. The LAM without vitrectomy procedure may provide a minimally invasive way of clot dislodgment and reperfusion without need for large retinal incisions near retinal vessels as with AAS.
Although this intervention may suggest benefit, it is certainly possible that the macular oedema spontaneously resolved as a result of reperfusion from recanalisation. We are uncertain as to which of these factors (LAM or recanalisation) resulted in significant improvement. It is our belief that the reperfusion after the procedure was mainly responsible for the dramatic clearing of haemorrhage and the resolution of the macular oedema. A prospective, randomised trial examining the potential benefits of 25 gauge without vitrectomy and 20 gauge AAS with vitrectomy procedures for BRVO is warranted.
Supported in part by NIH grant for vision research EY03040 and by an unrestricted grant from Research to Prevent Blindness.
The blunt 25 gauge nitinol flexible extendable retinal pick and the transconjunctival standard vitrectomy system (TSV) are disclosed to Bausch & Lomb Surgical, St Louis, MO, USA. The Microsurgery Advanced Design Laboratory (MADLAB) at the Doheny Retina Institute may receive royalties related to the sale of these instruments mentioned in this article to defray operating costs. The authors have no proprietary interests in any instrumentation in this article.