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Wednesday, 4 March 2015

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Removal of hydrogel scleral buckles.


Today, ophthalmologists in general, and retina surgeons in particular, continue to see patients who present with symptoms related to hydrogel buckle swelling. When swelling becomes symptomatic, surgical removal is usually the only option for symptom relief. Unfortunately, removal is not without risks. Surgeons must recognise the presenting symptoms and be aware of the friable characteristics of this material as well as the risks associated with removing these hydrogel buckles when planning surgical removal.

 

SYMPTOMS 

  • Swelling of a hydrogel buckle does not usually become symptomatic until 5 years after surgery, and it can occur up to 25 years after initial placement. It is unknown how many of these hydrogel buckles will eventually experience symptomatic swelling, but it has been calculated that at least 34% of the devices implanted will. 
  • Among the most commonly reported signs and symptoms are ocular pain or discomfort, ocular motility disturbance, scleral erosion, conjunctival erosion, cosmetic problems, and ptosis, but corneal astigmatism, tear film insufficiency, and a diagnosis of "orbital tumors" are other possible presentation scenarios. Because of the gradual nature of the swelling, symptoms tend to be progressive. Some symptoms may be related to the orientation of the buckle; for example, conjunctival erosion is more commonly associated with a radially oriented buckle, while ocular motility disturbance is more commonly associated with a segmental buckle.
  • A significantly swollen hydrogel buckle has an almost translucent, gel-like appearance and is usually easy to identify when examined. However, taking a thorough history, particularly regarding previous retinal surgery, is critical in making the correct diagnosis and developing a treatment plan. A hydrogel buckle should be considered if there is a history of retinal detachment surgery between 1985 and 2000.

 

SURGERY TECHNIQUE

  • The hydrogel material becomes friable as the hydrogel buckle degrades. This is critical when removing a symptomatic swollen buckle because it cannot be extracted with forceps alone. When the surgeon tries to grasp the degraded hydrogel, it breaks apart and comes out in small pieces. It is critical to remove all remaining material because it will continue to swell.
  • Scleral thinning, whether mild or severe, is not uncommon, so it should be carefully examined and kept in mind during surgical manipulation. Extensive opening of the overlying conjunctiva and the capsule surrounding the buckle is critical to minimizing this manipulation and lowering the risk of intraoperative scleral rupture. If there is an overlying silicone encircling band, it should be cut to free the hydrogel buckle and make removal easier.
  • For this procedure, blunt, curved Wescott tenotomy scissors work well. When they are closed, they form a blunt, gently curved instrument of just the right size for reaching the posterior sclera and gently manipulating the hydrogel anteriorly. When the scissors are opened, they can be used to cut tissue or sutures, reducing the need to change instruments.
  • A hydrogel buckle can be removed using one of two techniques. Boric acid can be used to dry out the buckle and make removal easier. This approach, however, should be used with caution, especially in cases of severe scleral thinning. Another method for easing removal is cryo-application (Video), which is especially useful in radial-oriented buckles. Aside from swelling and friability, the hydrogel buckle can sometimes show local calcification on the sclera. These calcified plaques can be left in place while the rest of the buckle is removed because they are extremely adherent to the sclera.

 

SURGICAL REMOVAL RISKS

  • The removal of the swollen hydrogel buckle is the only option for most symptomatic patients. However, removing a scleral buckle, regardless of the material (silicone or hydrogel), carries the risk of intraoperative scleral perforation and retinal redetachment.
  • When a symptomatic hydrogel buckle is removed, the reported incidence of retinal redetachment and intraoperative scleral perforation varies between studies. A risk of 11% for retinal redetachment or intraoperative scleral perforation was observed in our own recent study of 467 consecutive eyes, with loss of vision occurring in several of these cases. This is a serious risk, but as with all surgical indications, it must be balanced against the severity of the patient's symptoms, the condition of the fellow eye, and other influencing factors.
  • Active periocular infection and a history of multiple sessions of retinal surgery are two factors that are independently linked to an increased risk of scleral rupture.
  • Given that more than 34% of hydrogel buckles are removed due to symptomatic swelling, there appears to be a good chance that all hydrogel buckles that have ever been placed have already degraded and will be difficult to remove. Given the risks of removal, an important question to consider is whether all hydrogel buckles should be removed prophylactically.
  • Despite the fact that all patients who had an intraoperative scleral perforation also had a silicone encircling band, there was no significant correlation between the length of the hydrogel buckle and the risk of intraoperative scleral perforation in our study. As a result, it may not be necessary to remove all swollen hydrogel buckles as a precaution. However, in symptomatic cases, removal by an experienced surgeon is the only option for symptom relief. The patient's pain and desire for relief must be carefully balanced against the known risks.

 


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