Implementation Of Minimally Invasive Nasal Trabeculostomy (Mint) In Malawi

To overcome the poor availability and compliance of anti-glaucoma medications in Malawi, implementation of a minimally invasive glaucoma surgery (MIGS) is indicated. MINT is a simple surgical procedure that theoretically can be performed by all eye-surgeons in Malawi and provide better eye-care to the over 20 million citizens of this country. We report here a successful implementation of MINT surgery performed by a team of local ophthalmologists, one glaucoma specialist and 3 additional ophthalmologists from other sub-specialties.

All surgical procedures took place at Zomba Central Hospital in Malawi. Training of the surgeons was done one day before the surgeries in the operating room using artificial human eyes. All participants were of African origin and had ocular hypertension or early/moderate glaucoma. A pilot study was first performed, following which a pivotal study was initiated. Average age was 46±17 (range 17 to 80) years.  Most cases were completed in less than 10 minutes. The follow-up is ongoing.

The MINT is a hand-held robotic device, that when attached firmly to the trabecular meshwork band, and activated by a foot pedal, automatically creates a hole in the trabecular meshwork. This is repeated 5 times to create 5 holes in the nasal and inferonasal quadrants. The surgeon holds the MINT device with his dominant hand and views the angle structures directly via a "direct" gonio lens, held by his other hand. Retrobulbar anesthesia was given in all cases. A temporal paracentesis was used followed by an intra cameral injection of Myochol to constrict the pupil.  After filling the AC with a viscoelastic material the MINT device was introduced via the temporal paracentesis to approach the trabecular band in the opposite nasal side. 

13 pilot MINT procedures were done by one glaucoma specialist. There were no intra-operative complications. An average IOP of 14.5mmHg was recored day 1 post surgery with one patient having elevated intraocular pressure. Within 2 months, the average IOP decrease was 19.2±3.2 to 17.1±4.0 mmHg (p=0.16). The number of needed medications decreased by 73%, from 1.5±0.5 to 0.4±0.5 (P<0.0001). 59 MINT operations were then later performed by four eye-surgeons. An avereage IOP of 16mmHg was recorded on day 1 after surgery with one patient having elevated intraocular pressure. However, the number of needed glaucoma medications decreased by 95% from 1.1±0.31 to 0.06±0.24 (P<0.0001).

Using the MINT device, minimally invasive trabecular surgery can be performed without intraoperative complications by glaucoma and non-glaucoma specialists. This is true for young adults, adults and elderly alike. Early IOP spikes are rare. Glaucoma medication can be stopped immediately after the operation in mild and moderate glaucoma patients with only minimal risk of an early IOP elevation. Extended follow-up shows a persistent substantial decrease in the need for glaucoma medications, MINT can be implemented in many African countries where reliance on glaucoma medications is problematic.