New Technique for 25-g Iridotomy, Iridectomy, and Tumor Biopsy
The Finger Iridectomy Technique may be a
flexible and safe way to biopsy tumors.
T. FINGER, MD
Fine-needle aspiration biopsy (FNAB) has traditionally
been performed to diagnose anterior segment tumors and uveitic conditions through
a corneal or limbal approach.1-8
Though FNAB will typically yield a few cells for cytology, rarely does the surgeon
obtain enough tissue for histopathology or immunopathologic analysis. Additionally,
the FNAB also increases the risk of lacerating the lens, iris, and tumor blood vessels.
Finally, it has been my experience that up to 35% of patients can develop a significant
hyphema after FNAB.
1. Unlike a needle (right), the 25-g aspiration cutter (left) is blunt at its end
I have developted a new technique that can be used to biopsy iris
and iridociliary tumors and perform iridotomies or iridectomies through a 1-mm (self-sealing)
clear corneal incision. The Finger Iridectomy Technique (FIT) utilizes a 25-g aspiration
cutter for minimally invasive iris surgery.9,10
The FNAB uses a sharp-needle tip, which stabs and scrapes at cells
and maintains less control of suction. The FIT uses an aspiration cutter, which
possesses blunter, softer, physical characteristics and nibbles the tumor or iris
(Figure 1). I believe that the 25-g aspiration cutter lowers the incidencce of hemorrhage.
Also, the use of sodium hyaluronate 1%, (Healon, Advanced Medical Optics) helps
prevent blood formation from spreading and developing into media opacity. FNAB uses
aqueous without any viscoelastic and blood can quickly spread over the iris.
Typically, surgical iridectomy can be used to obtain larger specimens.
However, this procedure requires a relatively large corneal wound, suture-based
closure, and subsequent visual rehabilitation.5,8,11-14
The Finger Iridectomy Technique offers the benefits of a small
incision like FNAB as well as the large biopsy yield of iridectomy.
The FIT also offers a small-incision alternative for patients who require iridotomy
and iridectomy. The following is a step-by-step review of the technique for the
aforementioned procedures, as well as noted side effects and results.
In the cases I describe (20 total), the
FIT procedures were typically performed under conscious sedation, but topical anesthesia
can be used. For each patient, the face and eyes were prepped and draped for intraocular
surgery. An eyelid speculum was inserted and a 0.3 forcep was used to stabilize
the eye. Where necessary, a 25-gauge trocar was used to create a stab incision through
clear juxtalimbal cornea, into the anterior chamber.
A clear corneal incision was made to accommodate the 25-g aspiration
cutter and to minimize liberation of tumor cells.15
Acetylcholine chloride 10 mg/ml (Miochol-E, Novartis) is introduced into the anterior
chamber to induce miosis. Then, sodium hyaluronate 1% was used to maintain the anterior
chamber during surgery (and could be used to position the iris for biopsy
typically away from the natural lens).
At the end of surgery, an antibiotic-steroid solution was injected
beneath the conjunctiva. After 1 drop of timolol maleate 0.5% (Timoptic-XE, Merck)
and antibiotic steroid ointment were administered, each eye was patched and shielded.
Patients were discharged on the same day and given a regimen of a topical steroid,
antibiotic, and pharmacological agents to maintain intraocular pressure control.
For tumor biopsy, patients are not released from the operating
room until an adequate specimen is obtained; therefore, for these cases, either
procedure (iridotomy or iridectomy) was utilized to achieve tumor biopsy. Only 1
case, a sarcoid granuloma, resulted in the pathologist requesting an open biopsy
for tissue after several FIT specimens were biopsed.
FOR TUMOR BIOPSY
2. Slit-lamp photo of central tumor crater created with FIT small-incision
biopsy (white arrow). Note the dilated iris vessels along the tumor's posterior
margin (black arrows).
The indications for iris and iridociliary
tumor biopsy typically include atypical tumor, metastatic tumor with unknown primary,
and in cases where histopathologic confirmation of the diagnosis is required prior
to treatment. In addition, it is my recommendation that most small iris tumors be
watched for growth prior to biopsy or treatment. Because most iris melanomas are
associated with a low metastatic rate (related to their small size and isolated
location), biopsy must be balanced against the known risks of surgery or radiation
During the FIT procedures we performed, the use of a corneal entry
site ensured that any liberated cancer cells would exit the patient's body (addressing
concerns about tumor seeding).15
The entry site for each case was chosen to avoid crossing the pupil and the natural
lens. After acetylcholine chloride and sodium hyaluronate, the aspiration-biopsy
cannula (25-g aspiration cutter) was inserted into the anterior chamber as to approximate
the target tissue (the aspiration portal can be seen along its anterior surface).
For tumor biopsy, the aspiration port was rotated 90Þ as to come in contact
with the tumor for biopsy. If the tumor could not be engaged at 90Þ, then the
portal was progressively rotated posteriorly (toward the iris stroma).
Aspiration cutting was typically started on a suction of 300 mm
Hg at 600 cuts per minute. These settings were then adjusted to maximize the efficiency
of the process under direct visualization (trying to keep the cut rate as low as
possible). Each time the cutter was removed from the eye, the cutter-portal was
placed in balanced salt solution and the aspirate flushed (0.5 mL) from the effluent
tube utilizing suction from a 3 mL syringe.
Two to 3 biopsies were typically performed in each case.10
Specimens were immediately sent to the pathology department for cytological evaluation.
Once the pathologist confirmed that an adequate specimen was obtained, the residual
sodium hyaluronate 1% was removed from the eye by manual aspiration and irrigation.
The goal of tumor biopsy was to obtain tumor tissue for cytology,
histopathology, and immunohistochemistry. Therefore, only partial thickness of the
tumor and iris were sampled (Figure 2).
Figure 3. Left: An FIT iridotomy with
its characteristic scalloped edges. Right: A bright transillumination shadow reveals
that it is patent.
Iridotomy is typically performed for narrow
or closed angle glaucoma. We have performed FIT for this reason, but more commonly
when the tumor is within the iris stroma or when a diffuse iris melanoma was suspected.
In these cases, a minimally invasive surgical iridotomy was performed
utilizing the FIT "small-incision" technique (Figure 3).9
A juxtalimbal clear corneal incision was made in the superotemporal cornea with
a 25-g trocar. Acetylcholine chloride, then sodium hyaluronate, were introduced
into the anterior chamber for miosis and chamber stabilization. The 25-g aspiration-cutter
was inserted into the anterior chamber through the corneal wound and toward the
superonasal peripheral iris. Once engaged with iris tissue, aspiration, cutting,
and iridotomy were almost instantaneous.
Tumor excision can be performed utilizing
the FIT. I have use this technique on 1 melanoma where the tumor was relatively
small, near the pupil, and in a patient with corneal dystrophy. The FIT was also
used to remove an epithelial inclusion cyst.
Performing FIT tumor-excision or a large FIT-iridectomy takes
more time and requires subsequent injections of sodium hyaluronate, as well as a
second 1-mm incision (for an iris manipulator). Obtaining negative FIT tumor margins
would require the use of a new aspiration cutter for each margin.
Advantages of FIT iridectomy include: a small incision, rapid
rehabilitation, and its ability to spare peripheral iris (Figure 4). This can allow
for a more cosmetically acceptable ovoid pupil as compared to a standard "keyhole."
Though FIT yields more cells and relatively
large pieces of tissue compared to FNAB, we utilized special cytopathology and immunohistochemistry
techniques for tissue-specimen analysis. This includes the cytospin technique to
potentiate cytopathology and immunohistochemistry of retrieved tissue.9,10
Cytospin technique. A cytospin technique was used
to optimize the biopsy yield. Cytospin slides were cleaned with alcohol and assembled
with a slide filter card and sample delivery chamber, secured by a metal clip. Approximately
0.5 mL of fluid sample (3–5 drops) were added to the chamber, together
with an equal amount of cytospin collection fluid. After spinning at 1800 rpm for
2 minutes, the slides were removed from the cytospin chamber, further fixed in cytology
fixative (70% alcohol/formalin), and stained with haematoxylin and eosin.10
Tissue specimens. We have found that up to 0.5 mm
chunks of tissue were aspirated and cut utilizing this technology.9,10
This corresponds fairly well to the size of the portal
of the 25-g aspiration cutter. If pieces of biopsy specimen could be visualized
floating in the 3 mL syringe or cytospin collection fluid, the paraffin embedded
cellblock technique allowed for histochemical and immunohistochemical stains.
4. A slit-lamp photograph, taken 1 day after FIT iridectomy, reveals a surgically
enlarged ovoid pupil. The cornea is clear with minimal subconjunctival hemorrhage.
Diagnostic material was obtained in 19 of
20 biopsy cases (95%). One rather large sarcoid granuloma was found to be resistant
to both FIT and needle biopsy. The diagnosis was made by surgical iridectomy and
it resolved with systemic steroid therapy.
In most cases, FIT thinned the tumor, yielding relatively large
specimens that were amenable to cytology, histopathology, and immunohistochemical
analysis. Diagnoses included iris and iridociliary melanoma (n=12), iridociliary
melanocytoma (n=2), suspicious iris nevus (n=3), normal iris (n=1), epithelial inclusion
cyst (n=1), and sarcoid granuloma (n=1).
As a result of FIT-biopsy diagnosis, all but 1 iris and all iridociliary
melanomas were treated with palladium-103 ophthalmic plaque radiation therapy. Benign
iris tumors have been examined less frequently.16-18
One iris melanoma and an epithelial inclusion cyst were resected utilizing the FIT.
Iridotomies were found to be both patent and persistent (Figure 3).
Since April of 2003, no patient has lost
vision as a result of the FIT procedure.9,16
One patient with a 20-mm iridociliary melanocytoma and melanomalytic glaucoma developed
transient ocular hypertension. One patient developed a small (<5%) hyphema that
cleared within 1 week and did not induce glaucoma. One patient had elevated IOP,
treatable with topical medications. One patient developed a cataract, but only after
subsequent external beam radiation therapy.
Postoperative evaluations have revealed no wound leaks, endophthalmitis,
cataract, or secondary refractive errors. These findings have largely been attributed
to our use of a small incision, lack of irrigation, and the number of patients.
Anterior segment tumors are typically accessible
to biopsy through the cornea. Biopsy techniques have included standard iridectomy,
iridocyclectomy, transcorneal tumor biopsy, and FNAB.1,12,14
FNAB has been performed with sharp or blunt needles. Most centers
use sharp 21- to 25-g needles introduced through clear cornea to poke, slice, or
scrape the tumor. Cells are aspirated through the needle, utilizing extension tubing
and uncontrolled manual suction from a 5 mL or 10 mL syringe (also used for
specimen collection).19 Utilizing
FNAB for anterior segment tumors, one can expect a significant hyphema to occur.
In contrast, the relatively small footprint of the active portion
of the aspiration-cutter allows the surgeon to place the cutting element in a more
precise location. This is particularly important in at the iris root where the tip
of a needle would likely be in the ciliary body or into the sclera in order
to aspirate tumor. With FIT, the blunt end can rest against the angle while the
side portal samples tumor tissue. While FNAB utilizes uncontrolled manual aspiration,
FIT aspiration is mechanically controlled and measurable.
The Finger Iridectomy Technique introduces
the concept of using a 25-g aspiration-cutter to perform minimally invasive anterior
segment biopsies, iridotomy, iridectomy, and tumor excision.9,10
Relatively large specimens were retrieved that allowed for cytology, histopathology,
Subsequently, benign tumors were treated by observation and malignant
lesions by resection or palladium-103 ophthalmic plaque radiation therapy. This
technique may also be helpful to determine malignancy prior to enucleation and external
beam radiation therapy.16,20
Although we have not performed a prospective comparative study, my experience suggests
that as compared to needle-tip FNAB or surgical iridectomy, FIT may be safer and
1. Grossniklaus HE. Fine-needle aspiration
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2. Gupta M, Puri P, Jacques R, Rennie IG. Fine needle aspiration
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3. Marigo FA, Finger PT. Anterior segment tumors: current concepts
and innovations. Surv Ophthalmol. 2003;48:569-593.
4. Murray PI, Mooy CM, Visser-de Jong E, et al. Immunohistochemical
analysis of iris biopsy specimens from patients with Fuchs' heterochromic cyclitis.
Am J Ophthalmol. 1990;109:394-399.
5. Donovan DC, Aquilla JB. Sarcoidosis: diagnosis by iris biopsy.
Md Med J. 1986;35:493-495.
6. La Hey E, Mooy CM, Baarsma GS, de Vries J, de Jong PT, Kijlstra
A. Immune deposits in iris biopsy specimens from patients with Fuchs' heterochromic
iridocyclitis. Am J Ophthalmol. 1992;113:75-80.
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M, Mooy CM. Adhesion molecules in iris biopsy specimens from patients with uveitis.
Br J Ophthalmol. 1998;82:432-437.
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by iris biopsy. Graefes Arch Clin Exp Ophthalmol. 1998;236:717-719.
9. Finger PT. Small incision surgical iridotomy and iridectomy.
Graefes Arch Clin Exp Ophthalmol. 2005:1-2.
10. Finger PT, Latkany P, Kurli M, Iacob C. The Finger iridectomy
technique: small incision biopsy of anterior segment tumours. Br J Ophthalmol.
11. Veasey CA, Jr. Intraocular biopsy. Am J Ophthalmol.
12. Kirby DB. A technique for ttal biopsy of neoplasms of the
iris; report of a case of excision of a leiomyoma. Am J Ophthalmol. 1953;36:1225-1234.
13. Cleasby GW. Nevoxanthoendothelioma (juvenile xanthogranuloma)
of the iris. Diagnosis by biopsy and treatment with x-ray. Arch Ophthalmol.
14. Lai YL. [The biopsy of human iris]. Nippon Ganka Kiyo.
15. Karcioglu ZA, Gordon RA, Karcioglu GL. Tumor seeding in ocular
fine needle aspiration biopsy. Ophthalmology. 1985;92:1763-1777.
16. Finger PT. Plaque radiation therapy for malignant melanoma
of the iris and ciliary body. Am J Ophthalmol. 2001;132:328-335.
17. Finger PT. Tumour location affects the incidence of cataract
and retinopathy after ophthalmic plaque radiation therapy. Br J Ophthalmol 2000;84:1068-70.
18. Finger PT. Radiation therapy for choroidal melanoma. Surv
19. Augsburger JJ, Shields JA. Fine needle aspiration biopsy of
solid intraocular tumors: indications, instrumentation and techniques. Ophthalmic
20. Moshfeghi DM, Moshfeghi AA, Finger PT. Enucleation. Surv
T. Finger, MD, FACS, is director of The New York Eye Cancer Center, New York, NY,
Research supported by The EyeCare Foundation, Inc., New York, NY. He can be e-mailed
Retinal Physician, Issue: May 2006