An Alternate Technique for Goniotomy: Description of Procedure and Preliminary Results

Abstract

Purpose: Multiple glaucoma treatment modalities seek to lower IOP by bypassing or removing a portion of the juxtacanalicular trabecular meshwork. These procedures often require expensive implants or specialized surgical instruments. The authors developed a technique for ab interno goniectomy utilizing a standard disposable 25-gauge hypodermic needle. The surgical procedure-termed bent ab interno needle goniectomy (BANG)-and preliminary results are presented here.

Methods: A retrospective chart review was performed for all patients who underwent goniotomy using a modified hypodermic needle by one of the three authors between July 2017 and June 2018. The mean and standard deviation pre- and postoperative IOP and the number of glaucoma medications were calculated. The student paired t-test was used to compare pre- and postoperative data. A P-value of $<$ 0.05 was considered statistically significant.

Results: At postoperative month six, the mean IOP was 13.3 $\pm$ 2.5 mmHg (P = 3.6 $\times$ 10 ${}^{-7}$ ) on 0.5 $\pm$ 0.8 topical glaucoma medications (P = 0.01). A $\ge$ 20% reduction in IOP was achieved in 73% of patients. Seventy-three percent of patients required $\ge$ 1 fewer medication, while 73% of patients required no medications for IOP control. Forty-one percent of those treated achieved IOP $\le$ 12 mmHg.

Conclusion: The BANG procedure is a low-cost MIGS technique available to surgeons around the world with preliminary outcomes similar to more expensive alternatives.

Keywords: Glaucoma; Goniotomy; Microinvasive Glaucoma Surgery.

Figure 1

Fashioning a goniotome from a 25-gauge needle using a needle driver.

Figure 2

Histologic specimen of human trabecular meshwork following excision with a modified 25-gauge hypodermic needle. Light micrograph, hematoxylin–eosin, 200 $\times$ magnification.