Trabectome

The Trabectome is a surgical device that can be used for ab interno trabeculotomy, a minimally invasive glaucoma surgery for the surgical management of adult, juvenile, and infantile glaucoma. The trabecular meshwork is a major site of resistance to aqueous humor outflow. As angle surgeries such as Trabectome follow the physiologic outflow pathway, the risk of complications is significantly lower than filtering surgeries. Hypotony with damage to the macula (hypotony maculopathy), can occur with pressures below 5 mmHg, for instance, after traditional trabeculectomy, because of the episcleral venous pressure limit. The Trabectome handpiece is inserted into the anterior chamber, its tip positioned into Schlemm's canal, and advanced to the left and to the right. Different from cautery, the tip generates plasma to molecularize the trabecular meshwork and remove it drag-free and with minimal thermal effect. Active irrigation of the trabectome surgery system helps to keep the anterior chamber formed during the procedure and precludes the need for ophthalmic viscoelastic devices. Viscoelastic devices tend to trap debris or gas bubbles and diminish visualization. The Trabectome decreases the intra-ocular pressure typically to a mid-teen range and reduces the patient's requirement to take glaucoma eye drops and glaucoma medications (see references).…

The Trabectome is a surgical device that can be used for ab interno trabeculotomy, a minimally invasive glaucoma surgery for the surgical management of adult, juvenile, and infantile glaucoma. The trabecular meshwork is a major site of resistance to aqueous humor outflow. As angle surgeries such as Trabectome follow the physiologic outflow pathway, the risk of complications is significantly lower than filtering surgeries. Hypotony with damage to the macula (hypotony maculopathy), can occur with pressures below 5 mmHg, for instance, after traditional trabeculectomy, because of the episcleral venous pressure limit. The Trabectome handpiece is inserted into the anterior chamber, its tip positioned into Schlemm's canal, and advanced to the left and to the right. Different from cautery, the tip generates plasma to molecularize the trabecular meshwork and remove it drag-free and with minimal thermal effect. Active irrigation of the trabectome surgery system helps to keep the anterior chamber formed during the procedure and precludes the need for ophthalmic viscoelastic devices. Viscoelastic devices tend to trap debris or gas bubbles and diminish visualization. The Trabectome decreases the intra-ocular pressure typically to a mid-teen range and reduces the patient's requirement to take glaucoma eye drops and glaucoma medications (see references). The theoretically lowest pressure that can be achieved is equal to 8 mmHg in the episcleral veins. This procedure is performed through a small incision and can be done on an outpatient basis. By removing the primary resistance (the trabecular meshwork), aqueous humor can pass more freely into collector channels and aqueous veins. The Goldmann equation states that Intraocular Pressure = [Aqueous Humor Formation/Outflow] + Episcleral Venous Pressure. This equation states that free-flowing aqueous humor should cause intraocular pressure to drop to the same level as in the episcleral veins [26]. However, this is rare, and the average postoperative intraocular pressure is around 16 mmHg [27]. Spectral domain optical coherence tomography can be used to view collector channel diameter change, collapse or patency. Like human eyes, pig eyes have more outflow along the nasal drainage system than the temporal angle. Trabecular meshwork removal from the nasal can enhance outflow beyond physiological levels. It can also cause fluorescein to flow circumferentially, through small connections between Schlemm's canal-like segments, typical of a pig's angular aqueous plexus [3-5]. Reconstruction of outflow tracts via spectral domain optical coherence tomography have confirmed a correlation between aqueous spaces and collectors where flow was seen. However, these studies have also confirmed the existence of non-perfused vascular structures that could be part of the arterial or venous vascular system, or poorly perfused collector channels. Recent discoveries have shown valve-like structures that appear to guard collector channel orifices and collapsible aqueous veins 9, 10. These findings contradict the view that collector channel openings are round and unobstructed. Structural data has shown that flaps are suspended by string-like attachments. This research suggests that these attachments should be maintained during surgery, or that the flaps at the opening of collector channels should be removed. Electron microscopic images of the outer wall suggest that most are removed during trabectome procedures, together with their attachments and the trabecular meshwork [30].

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