Nd:YAG laser posterior capsulotomy performed under general anesthesia in the sitting position: a novel approach

Summary

We present a novel approach for performing an Nd:YAG laser posterior capsulotomy under general anesthesia with the patent in a seated position. We illustrate this approach in 2 cases, a young child and an adult patient with developmental delay. This technique may facilitate YAG capsulotomy in patients who cannot sit for the procedure.

Cases

We illustrate this technique with 2 cases of posterior capsular opacification (PCO) after intraocular lens implantation (IOL). Both cases underwent neodymium:yttrium-aluminum-garnet (Nd:YAG) laser posterior capsulotomy using the Lumenis Selecta Duet laser (Lumenis, Yokneam, Israel) at Penn State Eye Center. The first case was a 5-year-old child with a history of infantile anterior segment dysgenesis glaucoma after having undergone combined therapeutic penetrating keratoplasty (PK) for severe corneal edema and lens extraction with IOL implantation who developed PCO 4 months after surgery in the left eye (Figure 1A). The second case was a 37-year-old adult patient with trisomy 21 with developmental delay and keratoconus; he had undergone PK in the right eye 12 years prior and developed PCO in the right eye 13 years after cataract surgery (Figure 1B).

Figure 1.

A, A 5-year-old child undergoing sedated Nd:YAG laser posterior capsulotomy in an upright position in the operating room setting with the aid of an Invacare Spree 3G Pediatric Tilt-in-Space Wheelchair. The chair itself is raised using 12 total surgical steps, interlocked for stability. The procedure was performed without use of a standard YAG contact lens, and an assistant was used to elevate the left upper eyelid manually during the procedure. B, A 37-year-old adult patient with trisomy 21 and developmental delay and keratoconus sedated for an Nd:YAG laser posterior capsulotomy in the operating room setting. An Invacare Compass SPT Tilt-in-Space Wheelchair with an approximate 18-inch seat width and maximum support headrest (both posterior and lateral supports) was used, with arm rests and head rest removed for proper positioning of the patient’s head in the YAG laser headrest. The chair itself was raised using 4 total surgical steps, interlocked for stability. A standard YAG contact lens was used for this procedure.

In this procedure, general anesthesia was induced with the patient in the supine position on a standard operating room table. After endotracheal tube intubation, a soft cervical collar was placed around the patient’s neck for c-spine stabilization during positioning and treatment. The patient was then transferred to a fully reclined assistive chair, borrowed from our hospital’s inpatient physical therapy department (Tilt-In-Space Wheelchair; Invacare, www.invacare.com), and secured into position with the chair’s standard chest harness, side head supports, and ankle straps. Of note, the head was also secured to the headrest using surgical tape over gauze for complete stability. Once secured, the patient was slowly elevated to an upright seated position in approximately 10° increments, with pauses between elevation adjustments to monitor for any signs of hemodynamic instability. Once the patient was deemed to be hemodynamically stable in the fully upright 90° seated position, the patient and chair were carefully lifted onto a platform of interlocking surgical steps. The YAG laser table was moved into position and the patient’s chin and forehead positioned into the headrest. In order to accomplish proper positioning of the patient’s head within the YAG headrest, the surgical tape used to secure the head was removed and the chest harness loosened, and in some cases removed, to allow the patient’s body to lean forward. The armrests were also removed from the wheelchair to allow closer proximity to the YAG laser table. The patient’s arms were then allowed to rest on either side of the YAG laser table on top of pillow supports. Once the head was secured and properly positioned within the slit-lamp biomicroscope headrest, the posterior capsulotomy was performed in standard fashion.

At the completion of the procedure, the patient was re-secured into the chair, as prior to the procedure. The patient and chair were removed carefully from the interlocking surgical steps and placed back on the floor. The patient was then lowered into the fully reclined position. Finally, the patient was transferred back to the standard operating room table in the supine position, where anesthesia emergence and extubation were performed.

For the 5-year-old child, a Spree 3G Pediatric Tilt-in-Space Wheelchair (Invacare, www.invacare.com) with an approximate 12-inch seat width and maximum support headrest (both posterior and lateral supports) was used (Figure 1A). The height (120 cm) and weight (27.8 kg) of our patient was above the 75th percentile for age. We have experimented with a standard full size car seat for a smaller infant or toddler; however, the rigid side supports at the level of the child’s legs in a standard car seat do not allow adequate placement of the child’s head within the YAG headrest. We believe use of the smallest Invacare Tilt-in-Space Wheelchair with additional padding and support works best for this purpose.

For our adult patient, an Invacare Compass SPT Tilt-in-Space wheelchair with an approximate 18-inch seat width and maximum support headrest (Figure 1B) was used. Throughout the case, at least 1 person in the operating room was responsible for monitoring the overall positioning of the patient to avoid pressure-induced sores and to maintain the head in an upright anatomical position.

No systemic or ocular complications were encountered during or after the two procedures. Postoperatively, our 5-year-old patient experienced return of visual acuity from counting fingers to 20/250. The adult patient remained able to fix and follow before and after surgery, but consulting physicians gained the ability to view the posterior segment and red reflex more readily in the clinical setting. Both patients remained with a clear posterior capsular opening until at least their 1-year follow-up visit.

Discussion

PCO is the most common complication after both adult and pediatric cataract extraction with IOL implantation, with a varied incidence of <5% to 50%1 for uncomplicated senile cataracts and up to 100%2 for infants after cataract surgery. Risk factors for PCO have been reported to be younger age, female sex, diabetes, and uveitis along with surgical risk factors dependent on surgical technique and IOL selection.3 PCO results from the growth and re-proliferation of lens epithelial cells remaining after cataract surgery that migrate to the posterior capsule, where they approach the pupillary axis and cause not only visual blur for the patient but poor visualization for the ophthalmologist examining the posterior segment.1

The Nd:YAG laser is a solid-state laser with a wavelength of 1064 nm that can disrupt ocular tissues by achieving optical breakdown with a short, high-power pulse.4 Nd:YAG capsulotomy has been in use since the 1980s as a noninvasive clinical procedure to treat PCO using a series of focal, micropulse ablations to create an opening in the posterior capsule.5 The procedure requires the patient to remain in a seated position with their chin and forehead in contact with a traditional slit-lamp biomicroscope headrest. The ophthalmologist then has the option to place a specialty YAG lens onto the operative eye using an ocular lubricant for adequate ocular surface coupling. The procedure can also be performed without a lens. The patient must remain still for the duration of the procedure, which can be for minutes at a time. Given the need for patient cooperation and constant ocular fixation, patients who cannot cooperate, such as young children, developmentally delayed children or adults, and/or those patients with nystagmus, are not good candidates for the procedure in the clinical setting. There is also no currently available Nd:YAG laser that can be performed in the supine position for those patients whose body habitus cannot tolerate a seated position.

Traditionally, treating patients unsuited to Nd:YAG capsulotomy has involved performing a limited anterior vitrectomy and posterior capsulotomy in the operating room under general anesthesia. Both procedures carry the risk of increased intraocular pressure, inflammation, IOL dislocation, cystoid macular edema, and retinal detachment. The retinal detachment risk at 1 year post Nd:YAG laser, however, is considerably lower (1.4%)6 compared with open anterior vitrectomy (4.86%).7

Procedure time, though surgeon and patient pathology dependent, is likely similar for both procedures; the average time to perform the Nd:YAG laser in our 2 patients was 15 minutes. The time, however, to safely position a seated patient under general anesthesia may add to the overall case time; for example, in our adult patient, approximately 36 minutes of total anesthesia time for induction, patient positioning, and then emergence was needed. The Nd:YAG laser procedure, however, avoids the risk of intraocular infection inherent in any open ophthalmologic surgical procedure, such as anterior vitrectomy. For these reasons the authors prefer to weigh the risks, benefits, and alternatives specifically for each patient; we prefer the Nd:YAG laser over open anterior vitrectomy in those patients who would have a higher-than-average risk for retinal detachment (pathologic myopia, elongated axial length, previous history of retinal tear/detachment), patients who cannot be prevented from rubbing or causing trauma to the eye postoperatively, and those who cannot sit for a postoperative slit lamp examination (via stationary or portable slit lamp) for detecting complications specific to the procedure used.

An alternative to the seated position for an Nd:YAG laser capsulotomy under general anesthesia would be the lateral decubitus position as reported in great detail by Kinori et al8 in the pediatric population. In order to perform this procedure using the standard YAG slit lamp, the entire chin rest apparatus is removed. Given that we are a small academic practice with only one Lumenis Selecta Duet laser shared by both clinical and operating room staff, our Lumenis technical representative recommended against removal of the chin rest apparatus, which involves disconnecting both the hardware and the electrical wiring to the fixation bulb. Because removal of the chin rest is not recommended by the manufacturer, we recommend to those considering our technique that they consult their laser representative; reconfiguring the equipment could affect equipment warranty or be considered off-label use.

The potential risks, benefits, and alternatives for patients should be considered on a case-by-case basis, because patient repositioning from supine to seated is not without medical risk.9,10 Reported concerns of cerebral desaturation events, studied in the orthopedic literature during beach chair positioning for shoulder surgery, have a reported average incidence of 41.4%.9 The reported incidence of postoperative neurologic decline believed secondary to these events, however, is only reported at 0.004%.9 Further study in this area is needed, especially given the difference between the ophthalmologic versus orthopedic populations requiring this positioning.

In conclusion, Nd:YAG laser posterior capsulotomy under general anesthesia, with the patient in a seated position is possible in the operating room setting using the appropriate methods and equipment to ensure proper positioning, hemodynamic stability, and patient safety. We recommend close communication with and collaboration with the anesthesiologist before undertaking such a procedure. Consultation with the surgical center may be necessary to ensure all required safety protocols have been met.