|Year : 1998 | Volume
| Issue : 2 | Page : 87-89
A new curved vitreous cutter for managing phakic retinal detachment with proliferative vitreoretinopathy
S Natarajan, A Malpani, PK Nirmalan
Aditya Jyot Eye Hospital, Mumbai, India
Aditya Jyot Eye Hospital, Mumbai
Source of Support: None, Conflict of Interest: None
In the presence of proliferations anteriorly, adequate excision of the vitreous base is essential. To enable a good vitreous base excision, removal of lens often becomes necessary as it may be damaged while attempting to remove peripheral vitreous. To avoid damage or the need to remove the crystalline lens we have used a new modified curved vitreous cutter along with a wide angle observation system binocular indirect ophthalmomicroscope (BIOM). Use of BIOM during vitreous surgery enables easy viewing of the retinal periphery without the need for scleral depression. Sclerotomies are made as for any regular three-port vitrectomy procedure and the vitrectomy is carried out using the curved vitreous cutter, including the vitreous base, avoiding damage to the crystalline lens. The modified curved vitreous cutter is helpful in removing the peripheral vitreous without damaging the crystalline lens, giving the patient the advantage of intraocular lens implantation at a later date.
Keywords: Curved vitreous cutter, retinal detachment, proliferative vitreoretinopathy
|How to cite this article:
Natarajan S, Malpani A, Nirmalan P K. A new curved vitreous cutter for managing phakic retinal detachment with proliferative vitreoretinopathy. Indian J Ophthalmol 1998;46:87-9
Vitreous surgery has changed much since its inception, with acceptable innovative techniques being introduced for better management of the disease process and its attendant complications. Proliferative vitreoretinopathy is a common cause of failure of surgery for rhegmatogenous retinal detachment. In cases of proliferative vitreoretinopathy where proliferation is close to the vitreous base, adequate removal of the vitreous base is essential to prevent further recurrence., The conventional vitreous cutter with a straight shaft used for this purpose carries a high risk of iatrogenic trauma to the lens while negotiating the opposite vitreous base, limiting the amount of dissection possible. The curved cutter also reduces the risk of vitreous prolapse, retinal incarceration and retinal breaks that might occur while using the straight cutter through the same side sclerotomy for vitreous base excision. In phakic eyes, this often necessitates lensectomy of a clear crystalline lens to aid visualisation and tissue dissection in the anteroperipheral part of the posterior segment. We have designed a new curved vitreous cutter to avoid iatrogenic damage to the lens while performing adequate vitreous base excision. Further, the use of binocular indirect ophthalmomicroscope during surgery facilitates wide angle visualization of the peripheral retina up to the ora, without excessive rotation of the globe.
| Materials and Methods
A new vitreous cutter with a gentle curve to the shaft at an angle of 160° was used for vitrectomy (Figure). This has not been reported elsewhere. This new curved vitreous cutter has a cutter shaft length of 30 mm and an arc of curvature of 45°. The dimensions of the cutter/ suction port are 0.1 x 0.4 mm. The cutter has a guillotine cutting action and pneumatic mechanism of movement.
Ten phakic eyes with retinal detachment and proliferative vitreoretinopathy of grade CA 6 or more, types 4 and 5 (pre-equatorial circumferential proliferation and anterior displacement covering ≥6 (clock hours), were selected randomly for the study. All patients had Snellen visual acuity measured, and Schiotz tonometry, slit lamp examination and indirect ophthalmoscopy done preoperatively. Preoperatively, all 10 patients had clear crystalline lenses. All patients were informed about the use of a new cutter and its perceived advantages and disadvantages. Informed consent was obtained from each patient. The perceived advantages were less risk of lenticular trauma and more complete vitreous base excision, reducing the chances of recurrence. The disadvantage was that it was a new instrument. Binocular indirect ophthalmomicroscope was used during surgery to facilitate easy viewing of the retinal periphery up to the ora without the need for scleral depression. Sclerotomies were made as for any regular three-port vitrectomy procedure at 3.5 mm from the limbus and the curved vitreous cutter was used for vitrectomy and the vitreous base excision, constantly checking if it touched the posterior part of the lens at any point of use. The crystalline lens was also checked for any evidence of trauma at the end of the surgery. Routine postoperative care was advised and all patients had a slitlamp examination and indirect ophthalmoscopy on all follow-up visits under full mydriasis, to look for any evidence of iatrogenic trauma to the crystalline lens. All patients were followed up for a minimum period of 1 year.
There was no difficulty in either introducing the curved vitreous cutter through conventional sclerotomy or in intraocular manoeuvering of the instrument. At no point of use did the curved vitreous cutter touch the crystalline lens in the 10 phakic eyes operated upon. Postoperative course of all patients was uneventful and there was no evidence of iatrogenic trauma to the lens on follow-up visits. All patients had an attached retina on binocular indirect examination on follow-up visits.
The most common cause of failure of surgery for rhegmatogenous retinal detachment has been proliferative vitreoretinopathy. The basic principles of treatment of proliferative vitreoretinopathy include closure of all retinal breaks, relief of the retinal traction and minimizing recurrence of traction. Adequate excision of the vitreous is essential to minimize chances of recurrent traction. This requires proper viewing of the retinal periphery and instrumentation designed for easy movements within the eye causing minimum or no damage to other intraocular structures. In routine pars plana vitrectomy in phakic eyes this often necessitates lensectomy of a clear crystalline lens to aid visualization and access to the retinal periphery, thus placing on the vitreoretinal surgeon an additional responsibility of aphakic visual rehabilitation. Despite advances aphakic visual rehabilitation remains unsatisfying and difficult.
Also, a normal clear crystalline lens is being sacrificed for reasons not related to the disease process. The use of binocular indirect ophthalmomicroscope during vitreous surgery [4, 5] provides a wide angle view of the fundus up to 90°, good stereopsis with good depth perception, and a non contact system that protects the cornea. This helps in performing surgery without the need for excessive rotation of the eyeball.
Lensectomy is still often required due to the iatrogenic damage to the lens caused by the shaft of the straight vitreous cutter while attempting adequate excision of the vitreous base. The new curved vitreous cutter has been designed with an angle of 160° with a gentle curve such that the opposite vitreous base can be accessed and operated without any touch or damage to the posterior surface of the lens in situ. This curvature was arrived at after trying out various designs in pseudophakic eyes initially. One initial design had a curvature of 140° which we found to be too acute. Intraoperative touch of the intraocular lens implant was noted on using this curvature. Another difficulty experienced while using this curved cutter was during the removal of posterior vitreous. The present design takes care of this drawback. At no point of use did the new curved vitreous cutter touch the crystalline lens intraoperatively. At the same time adequate vitreous base surgery was possible.
None of the 10 phakic eyes had any evidence of iatrogenic trauma to the lens on follow-up visits. The gentle curvature of 160° of the vitreous cutter ensured that it did not cause damage to other intraocular structures during intraocular manoeuvers to access the opposite vitreous base. The cutting action is not being compromised as the cutter forms part of the arc of a circle. We have also noted that the curved vitreous cutter has been useful for anterior vitrectomy in aphakic eyes without additional damage to the iris, and in performing membranectomy for thick after cataracts. Another perceived advantage has been in deep sunken eyes in which manoeuvering of the straight cutter has often been difficult particularly while performing inferior iridectomy at 6 o'clock. Being a modification of the existing design, there is no significant learning curve. The main advantage of the new curved vitreous cutter lies in its easy access to the vitreous base without additional intraocular damage. The curved vitreous cutter can be used for vitreous debulking in anterior proliferative vitreoretinopathy, with fewer complications than the straight cutter. However, in some cases it may be necessary to remove the lens to attain retinal reattachment and to prevent reproliferation. Even in cases where 360° retinectomy is done, vitreous debulking upto the ora serrata can be done using the curved vitreous cutter especially with the simultaneous use of BIOM.
We acknowledge the collaboration with D.O.R.C., Oude singel 2, 3211 BA Geervliet, Holland, in developing this curved vitreous cutter.
| Financial Disclaimer
None of the authors have any financial interest in this curved vitreous cutter.
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