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Restoring the Intermediate Segment
|Approaches to traumatic
iridodialysis and cyclodialysis.
BY WILLIAM ERIC SPONSEL, MB, CHB, MD
|Ocular trauma frequently damages the cornea,
lens, and retina. Standard methods of managing such injuries use ultrasonic,
radiological, slit-lamp, and ophthalmoscopic imaging. Because damage to
the intermediate segment of the eye (ie, the iris root, zonule, and ciliary
body) is obscured from view, it is often ignored. The clinician's failure
to detect and resolve anterior uveal injury can result in either profound
hypotony that may lead to phthisis or ocular hypertension with ax-onal loss.
8oth conditions are painful and may cause blindness.
Before the advent of ultrasound biomicroscopy (UBM), the available methods for viewing the intermediate segment included gonioscopy and liquid immersion ultrasound. Hyphema, corneal edema, and a collapse of the anterior chamber preclude gonioscopy in many trauma cases. Immersion ultrasound provides insufficient detail to help direct and facilitate careful surgical exploration. Contradistinctively, preoperative UBM provides the surgeon with useful 3-D mapping information. A thoughtful application of UBM findings may lead to surgical success, even when one's expectations are appropriately guarded. With UBM, the precise placement of drainage sclerostomies over supraciliary effusion and hemorrhage is possible, as is identifying cyclodialysis zones that require resuturing of the scleral spur and reattachment of the ciliary body. Optical coherence tomography may ultimately provide similarly useful images, but its resolution diminishes in patients who have dark uveal pigmentation, thus limiting its clinical applicability.
In the following three patients, all of whom presented within a few weeks of each other at the South Texas Medical Center in San Antonio, my colleagues and I used a P45 Ultrasonic Workstation UBM (Paradigm Medical Industries, Inc., Salt Lake City, UT), courtesy of Erin Doe, MD, a glaucomatologist at the Brooke Army Medical Center in Fort Sam Houston, Texas. The UBM's
50-MHz VHF mode provides microscopic digital images that reveal hidden anatomy and pathology beneath the iris, sclera, and ciliary body.
Severe, Bilateral Trauma
Cyclodialysis Cleft With Supraciliary Fluid Pockets
An 81-year-old Hispanic male presented with a painful left eye. He had a history of corneal stromal edema. He had been scheduled for assessment in the cornea clinic with presumptive Fuch's dystrophy, but I was invited to assess his hypotony in the glaucoma clinic when he first arrived. His BCVA was 20/200 OS, and his IOP was <1 mm Hg OS. A thorough patient history and careful gonioscopy revealed that he had undergone bilateral cataract extraction 5 years earlier. Postoperatively, the patient's visual acuity remained 20/20 OO, but his left eye irregularly cycled through periods of relative clarity and total blurring. He demonstrated a mild, afferent pupillary defect in his hypotonous left eye, and a slit-lamp fundus examination revealed macular folds ¦ consistent with hypotony maculopathy. Gonioscopy confirmed pigmentary accumulation inferiorly and temporally and a small, single-clock-hour, nondisplaced cyclodialysis superiorly.
UBM revealed fluid extending downward to the A- and 7-o'clock positions, on either side of the small cyclodialysis cleft. The scarred area at the 12-o'clock position contained little adjacent supraciliary fluid. I prescribed Cy-clogyl 2% (Alcon Laboratories, Inc.) q.i.d. for his left eye instead of primary repair. Within 1 month, the patient's left eye had an IOP of 10 mm Hg, a clear cornea, and no residual macular folds. His visual acuity, which had previously vacillated between hand motions and 20/40 since cataract extraction, now measured 20/15 OS. UBM with cycloplegia showed an obstruction of the small cyclodialysis cleft with peripheral iris root and a spontaneous resorption of all the supraciliary fluid. Later, the patient was treated with surgical closure of the cyclodialysis cleft, which allowed the restoration of his normal pupillary function. He had no further ocular problems.
Hemi-lridodialysis and Cyclodialysis
An 8-year-old Hispanic male had suffered an injury to his right eye from a BB gun 11 days before presenting. His IOP had been almost zero since the injury. The temporal iris was detached and scrolled nasally. The iris was encased in fibrin and vitreous, and the temporal zonule was destroyed (Figure 3). The lens appeared to be intact, but there was no evidence of macular function. His visu¬al acuity was < 20/400 OD. The boy was in great pain and appeared at risk for recurrent bleeding.
Figure 4. The surgeon creates a stepped incision (A) and a half-thickness planar corneoscleral ridge (B). He unscrolled the iris root (C and D) and attached the peripheral iris to the sclera with 10-0 nylon (E). After per¬forming a manual vitrectomy (F), he created sclerostomies over the largest areas of supraciliary and pars plana/choroidal detachment (G). Finally, the surgeon implanted a tube shunt (H and I).
UBM showed extensive cyclodialysis and supraciliary effusion with angle recession beyond the ends of the cyclodialysis. The patient was scheduled for surgical repair of the cyclodialysis and the iridodialysis with an anterior vitrectomy and transscleral drainage. Based on my experience in case 1,1 tentatively scheduled optional implantation of an Ahmed Glaucoma Valve and a scler¬al graft.
After carefully performing the peritomy, I created a stepped incision posterior to the limbus (Figure 4A). I used a crescent blade to create a half-thickness planar corneoscleral ridge for the full extent of the wound (Figure 4B). Keeping the internal Descemet's openings below 2 clock hours at a time will avoid an expurgation of the ocular contents. After clearing overlying fibrin and vitreous and carefully instilling viscoelastic, I unscrolled the iris root (Figures 4C and D). I attached the peripheral iris to the anterior lip of the stepped incision with 10-0 nylon sutures (Figure 4E). After closing the central area, I carefully opened the adjacent area with a blade and performed another vitrectomy (Figure 4F).
After repairing the anterior and intermediate segments, I strategically placed sclerostomies (Figure 4C) overlying the largest areas of supraciliary and pars plana/choroidal detachment as shown on preoperative UBM. I completed a slow, repetitive transzonular fluid replacement wi h BSS using a 30-gauge cannula via an oblique 25-gauge paracentesis. This process continued as long as fluid exited through each sclerostomy. Finally, I placed the Ahmed Glaucoma Valve (Figures 4H and I) to avoid postoperative ocular hypertension and associated pain that could readily compromise my efforts.
The child rapidly recovered from the 6-hour procedure. He had a central oval pupii with normal sphincter function, a UCVA of 20/30 OD, full peripheral visual fields, and a consistent IOP of approximately 16 mm Hg without medication.
The three cases presented herein illustrate the utility of UBM in the assessment of intermediate segment trauma. I now recognize that, in some cases, prophylactically placing a shunt may be prudent after the surgical repair of the trauma, because postoperative nausea or eye-rubbing could readily undo the meticulous repair. Large clefts must be repaired primarily. In smaller cyclodialyses, if the detached scleral spur remains aligned with its normal anatomic attachment site, pharmacologic cycloplegia may temporarily induce the cleft to reseal, allowing spontaneous resorption of massive quantities of circinate supraciliary fluid. Most importantly, the precise attachment of the scleral spur is key to the success of all repairs. If resutured too far anteriorly or posteriorly, the ciliary body will remain detached with persisting supraciliary fluid, and long-term hypotony and eventual phthisis are likely. Thorough supraciliary drainage facilitates initial repair and helps stabilize the repositioned uveal tissue.