Quality measures of macular surgery – can we characterize surgical skill?

Abstract

Purpose : We aimed to objectively characterize quality measures of macular hole surgery to provide better patient care and improve surgical training. This study focuses on internal limiting membrane peeling which is considered one of the most challenging procedures in macular surgery.

Methods : We retrospectively examined 3 full-thickness macular hole case series. Patients operated by 1) a novice surgeon, 2) this same novice surgeon after 1 year of experience (intermediate group) and 3) an experienced surgeon. Treatment consisted of pars plana vitrectomy, internal limiting membrane peeling and gas tamponade and all patients were examined over 1 year postoperatively. Primary outcome was ganglion cell layer (GCL) thickness (internal limiting membrane - inner plexiform layer thickness of the 7.0 x 7.0 mm macular area) measured with OCT. A cutoff between healthy and pathological ganglion cell layer was defined as <1.96 SDs below mean ganglion cell layer thickness. Secondary outcome was retinal function as measured by confocal microperimetry using a custom scanning protocol.

Results : 29 patients were examined; 11, 7 and 11 patients belonging to the novice, intermediate and experienced surgeon group, respectively. Mean GCL thickness across groups was 102 µm and pathological GCL thickness was defined as <59 µm. Median GCL volume defect was 47.0x10⁶ µm³, 12.2x10⁶ µm³ and 8.8x10⁶ µm³ in the novice, intermediate and experienced surgeon group, respectively. The novice group differed significantly from both the intermediate and experienced surgeon group (p = 0.004 and p = 0.0004, respectively). The difference between the intermediate and experienced surgeon group did not meet statistical significance (p = 0.07). A subset of 7 patients underwent microperimetry measurements. A univariate linear model revealed that GCL volume defect seemed to influence microperimetry measured retinal sensitivity (p = 0.02).

Conclusions : Forceps induced ganglion cell layer damage often occurs with initiation of internal limiting membrane peel in full-thickness macular hole surgery. Novice surgeons risk creating significant damage to the structure and function of the inner retina. With surgical experience the structural and functional damage is significantly reduced.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.