What are the causes of redetachment post scleral buckling and cryotherapy?

Causes of Redetachment Post Scleral Buckling and Cryotherapy

The primary causes of redetachment after scleral buckling and cryotherapy are inadequate treatment of the original retinal breaks (particularly at the anterior borders of horseshoe tears), buckle malposition, new break formation, and insufficient chorioretinal adhesion. 1, 2, 3

Technical Failures During Initial Surgery

Inadequate Treatment of Original Breaks

• The anterior border of horseshoe tears is the most common site of treatment failure because this area is difficult to visualize and frequently receives inadequate cryotherapy coverage 1, 2
• Insufficient anterior extension of cryotherapy—failing to extend treatment to the ora serrata when complete surrounding of tears is impossible—is a significant risk factor for surgical failure 1, 2
• All retinal breaks must be completely surrounded by cryotherapy application, as incomplete treatment allows continued fluid passage into the subretinal space 1

Buckle-Related Problems

• Buckle malposition occurs when the scleral buckle is not properly positioned beneath the original break, leaving the tear inadequately supported 3
• Inadequate buckle height fails to provide sufficient indentation to relieve vitreous traction on the retinal break 3
• The break may become elevated off the buckle due to progressive vitreous traction, even if initially well-positioned 3

Delayed Adhesion Formation

• The chorioretinal adhesion from cryotherapy is not firm or complete for up to 1 month following treatment, during which continued vitreous traction can pull tears beyond the treated area 1, 2
• This delayed adhesion formation creates a vulnerable period where inadequate initial treatment coverage becomes clinically apparent 1
• Insufficient chorioretinal adhesion can result from inadequate cryotherapy application or premature vitreous traction before scar maturation 3

New Break Development

• New retinal breaks develop in 10-16% of patients during long-term follow-up, with pseudophakic patients at particularly higher risk 1, 2
• These new breaks occur in previously untreated areas and represent a distinct mechanism from inadequate treatment of original breaks 3
• Missed breaks at the time of initial surgery—breaks that were present but not identified—also contribute to early redetachment 3, 4

Proliferative Vitreoretinopathy (PVR)

• Periretinal proliferation accounts for a significant proportion of final failures after scleral buckling surgery 5
• PVR can develop postoperatively and create tractional forces that overcome even adequate buckle placement and chorioretinal adhesion 3, 6

Patient-Specific Risk Factors

• Pseudophakic patients have higher rates of both missed breaks at initial surgery and new break formation during follow-up 2, 4
• Difficulties in peripheral retinal visualization in pseudophakic eyes contribute to undetected breaks, with one study showing 24.5% of pseudophakic retinal detachments had undiagnosed breaks 4
• The absence of posterior vitreous detachment at the time of surgery in high-risk eyes (myopia, lattice degeneration) increases long-term risk 7

Clinical Implications for Prevention

• Meticulous examination to identify all retinal breaks before surgery is essential, particularly in pseudophakic patients where visualization is challenging 4
• Cryotherapy must extend anteriorly to the ora serrata with adequate coverage of horseshoe tear anterior borders 1, 2
• Recognition that the first month postoperatively represents a vulnerable period before complete chorioretinal adhesion formation 1, 2
• Long-term follow-up is necessary given the 10-16% incidence of new break formation over time 1, 2