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Year : 2020  |  Volume : 28  |  Issue : 1  |  Page : 21-23

21G Needle-Assisted Pterygium Excision (21-GNAP): A Novel Safe Approach

Department of Ophthalmology, University of Uyo, Nigeria

Date of Submission01-Mar-2020
Date of Decision09-Apr-2020
Date of Acceptance05-May-2020
Date of Web Publication07-Sep-2020

Correspondence Address:
MBBS, FMCOph, MPA, MSc (Ed.) Emmanuel Olu Megbelayin
Department of Ophthalmology, University of Uyo
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/njo.njo_8_20

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Aim: To determine surgical efficacy of 21G needle-assisted pterygium excision. Method: A pictorial review of pterygia excised at different levels of maturity and diverse clinical history using a 21G hypodermic needle and a colibri. Ten pterygia were excised of which grade 3 were six and grade 2 were four. Nine cases were primary pterygia and a case was recurrent. The author was the only surgeon. Result: Cases reviewed showed minimal or no residual pterygial tissues post-operatively. Pterygial beds had smooth corneal optical surfaces, there were no perforations or undue corneal “guttering” from irregular cuts, no exuberant tissue formation like pyogenic granuloma or recurrence at 6 weeks of follow-up. Overall, slit lamp images were comparable with conventional “grab and cut” with surgical blade or scissors. Conclusion: 21G Needle-Assisted Pterygium (21-GNAP) excision is cheap, safe, and easy-to-learn new modality of excising all forms of pterygial and ocular surface masses.

Keywords: Excision, pterygium, 21-gauge hypodermic needle

How to cite this article:
Megbelayin EO. 21G Needle-Assisted Pterygium Excision (21-GNAP): A Novel Safe Approach. Niger J Ophthalmol 2020;28:21-3

How to cite this URL:
Megbelayin EO. 21G Needle-Assisted Pterygium Excision (21-GNAP): A Novel Safe Approach. Niger J Ophthalmol [serial online] 2020 [cited 2022 Aug 8];28:21-3. Available from:

  Introduction Top

A pterygium (plural pterygia) is a triangular fibrovascular subepithelial ingrowth of degenerative bulbar conjunctival tissue over the limbus onto the cornea. It typically develops in patients who have been living in hot climates and, as with pinguecula, may represent a response to ultraviolet exposure and to other factors such as chronic surface dryness. A pterygium is histologically similar to a pinguecula and shows elastotic degenerative changes in vascularized subepithelial stromal collagen in contrast to pingueculae, pterygia encroach onto the cornea, invading the Bowman layer. Pseudo-pterygium appears similarly clinically but is caused by a band of conjunctiva adhering to an area of compromised cornea at its apex.[1] If not promptly removed, pterygium unleashes significant cosmetic blemish and defective vision.

Numerous surgical techniques have been described since the early 1960s, including the bare sclera technique, simple closure with absorbable sutures, sliding flap, rotational conjunctival flap, conjunctival autoplasty, mucous membrane graft, and conjunctival autograft.[2],[3] These techniques involve grasping the pterygial head and avulsing from its base or grasping and gradually dissecting it off its base using a surgical knife or conjunctival scissors.

21G hypodermic needle has been noted by the author to possess the right size, finesse, and ergonomics to neatly separate pterygium from its bed with little or no worry about corneal perforation. 21G needle is being reported by this article as a viable alternative to surgical knife, razor blade, scissors, or similar tools hitherto employed in pterygium excision.

Surgical Procedure and Adjuvants

Items required are ophthalmic operating microscope, lid speculum, colibri, cotton buds, conjunctival scissors (optional). A sterile tray is set in the usual way. For a right-handed surgeon, best sitting position is above the patient to operate right nasal pterygium and left temporal pterygium. This position also allows operating left nasal pterygium and right temporal pterygium for a left-handed surgeon. Sitting at patient’s right temporal side allows for good grasp of pterygial heads at left nasal areas and right temporal areas for the right-hand. This reverse is the case for the left-handed.

A good initial grasp should be ensured at the tip of the head of pterygium close to Stocker’s line. The grasped head is gently lifted with sufficient but minimal force to avoid avulsion (shearing) [see [Figure 1] and [Figure 2]]. The right hand holding 21G with the bevel face up and one of the sharp edges advanced into bed of the pterygium, ensuring that every of its anatomic part has been lifted off the cornea. The same plane is followed until pterygium is dissected fully from the cornea to the conjunctiva. After sufficiently dissected, the same needle or conjunctival scissor is used to severe the separated pterygial tissues and attached conjunctiva. Further procedures could be carried out such as amniotic graft, conjunctival auto-graft, Mitomycin 5FU application as necessary.
Figure 1 Grasping pattern and needle positioning

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Figure 2 Pictorial representation of sampled cases

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The implication of avulsion that escapes needle control, if it occurs, is that the entire pterygium may be severed from its head leaving behind superior and inferior fangs. If this occurs, grasp each fang and repeat the initial process making sure the fangs are lifted with 21G needle leaving no pterygial tissues behind. Then all three parts: the initial bite and the two fangs, are then dissected off the cornea and amputated with conjunctival scissors or same 21G needle.

  Discussion Top

The field of Ophthalmology has witnessed massive innovations from surgical techniques,[4],[5] ideas[6],[7] and ophthalmic equipment. 21G Needle-Assisted Pterygium excision (21-GNAP) is a novel and safe method of pterygium removal with flat-surfaced learning curve that adds to the burgeoning body of ophthalmic innovations.Excision as a modality of removing pterygium is not new.[8] What continues to evolve is the modalities of preventing its recurrence with each method having variable outcomes. Various methods exist to disinsert pterygial head before dissecting the belly from corneal epithelium to which it is attached by variable degree. At times adhesions are so tough that cicatrizations make separation during surgery tedious. 21G green hypodermic needle is a cheap “scalpel” for a clean disinsertion and subsequent dissection of pterygium. Apart from limiting the chance of inadvertent corneal perforation associated with surgical knife or razor blade fragment, there is little or no residual pterygium on corneal surface with a relatively smoother optical surface. The author believes that in the event of inadvertent intraocular penetration by the 21G needle, the resultant opening is likely to be a self-sealing perforation unlike a full-thickness several millimeters lacerations reported as a complication of conventional blade/surgical knife excision. Till date, the authors have not experienced needle penetration during pterygium excision. Therefore, corneal perforation is thought to be a rare and unlikely complication of 21-GNAP.

  Conclusion Top

Surgical firmament remains accommodative to innovations that ease life and enhance its quality while increasing access and decreasing cost. With just a colibri and a 21G hypodermic needle, pterygium could be safely removed with minimal or no effect on ocular surface architecture.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Bowling B. Kanski’s clinic ophthalmology: a systemic approach. China: Elsevier Publishers International, 2016.  Back to cited text no. 1
Guillermo R. Surgical management of pterygium. Techniques in Ophthalmology 2003;1:22-28.  Back to cited text no. 2
Castroviejo R. Atlas of keratectomy and keratoplasty. Philadelphia: WB Saunders, 1966  Back to cited text no. 3
Agarwal A, Jacob S, Agarwal A. Aberropia: a new refractive entity. Ocular Surgery News 2002;20:14-19.  Back to cited text no. 4
Agarwal A, Jacob S, Kanjani N. Aberropia: a new refractive entity. In Boyd BF, Agarwal A, eds. Wavefront analysis, aberrometers and corneal topography. Panama, Republic of Panama: Highlights of Ophthalmology International 2003;333-42.  Back to cited text no. 5
Megbelayin EO. Propounding Darktom Theory: ophthalmologist perspective. Eur J Prev Med 2017;5:83-86.  Back to cited text no. 6
Megbelayin EO. Aberropia: concept and misconception. South Africa Ophthalmology Journal 2012;7:23-26.  Back to cited text no. 7
Chowdhury S. New surgical technique for pterygium: conjunctival in situ autograft. J Univer Surg 2018;6:1-4.  Back to cited text no. 8


  [Figure 1], [Figure 2]


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