Pars Plana Vitrectomy for the Treatment of Tractional and Degenerative Lamellar Macular Holes: Functional and Anatomical Results
Figueroa M, Govetto A, Steel D, et al. Pars Plana Vitrectomy for the Treatment of Tractional and Degenerative Lamellar Macular Holes: Functional and Anatomical Results. Retina, Nov 2019; 39: 2090 – 2098.
The diagnosis of lamellar macula hole (LMH) was first described by Gass in 1976 and major advances in imaging have led to better understanding of the pathology. However, the diagnosis and nomenclature of LMH is not uniform in the literature. Recently, Govetto et al in 2016 proposed two distinct subtypes of LMH: degenerative with “top hat” appearance on OCT (recently renamed LHEP: lamellar macular hole associated with epiretinal proliferation) and tractional with “moustache” shaped appearance on OCT, arguing they may represent different pathological conditions with different clinical implications (Figure 1). The following study was conducted to analyses the functional and anatomic outcomes of these two sub-types post-PPV.
Figure 1 from Figueroa M et al. Retina 2019.
Study Design: multi-center, retrospective observational study including patients diagnosed with tractional or degenerative LMH between January 1, 2010 and January 1, 2017. Inclusion criteria included presence of tractional or degenerative LMH treated with PPV and membrane peeling, with a minimum of 6-month follow-up, and with pre- and post-op SD-OCT imaging. Exclusion criteria included any other macular pathology limiting vision.
All patients underwent 23- or 25-gauge PPV with membrane peeling by 4 vitreoretinal surgeons with ILM removal performed with use of Kenalog, Brilliant Blue G, or indocyanine green. Combined phacoemulsification cataract surgery was completed at the discretion of the surgeon. The eyes were filled with BSS, C3F8 or SF6 at the end of the case. Patients were evaluated at least at 1 and 6 months after surgery. Primary anatomical success was defined as absence of breaks in inner fovea and absence of intraretinal hyporeflective spaces on OCT. Immediate healing was defined within 1 month after surgery and delayed healing as seen at greater than 1 month after surgery.
Results: 103 eyes of 103 patients were enrolled – 38 were men and 65 were women. Mean follow was 31 months. 52 eyes were phakic and the remaining were pseudophakic. Tractional LMH was diagnosed in 77 eyes and degenerative LMH was diagnosed in 26 eyes.
Preoperative: mean BCVA was LogMAR 0.39 (20/50) in tractional LMH and LogMAR 0.56 (20/72) in degenerative LMH, P < 0.001. PMM was present in all tractional LMH and LHEP was present in all degenerative LMH. Preoperatively, 13 of 26 eyes with degenerative LMH had outer retinal disruption while this was only seen in 11 of 77 eyes with tractional LMH, P < 0.001.
Surgical intervention: 82.5% cases were performed with 23-gauge PPV and the rest with 25-gauge PPV. 12.6% eyes underwent combined phaco-PPV. Double peeling of membrane and ILM was done in 96.1% of eyes. Brilliant Blue G was used in 66.6% of cases, ICG in 16.2% of cases, and in the remainder, chromodissection was not performed.
- Primary anatomical success was achieved in 94.2% of eyes, with 5 tractional and 1 degenerative LMH unable to achieve foveal anatomy restoration.
- Delayed healing was more frequent in the tractional subtype and immediate healing was more common in degenerative subtype (P < 0.001).
- Outer-retinal disruption resolved in 29.2% of eyes (5 of tractional and 2 of degenerative subtype) at last follow-up.
- BCVA improved significantly in both groups (tractional 20/30 and degenerative 20/50).
- Type of tamponade did not significantly change anatomic success rate.
- Three eyes developed full-thickness macular holes after 8 months (2 degenerative and 1 tractional LMH).
- Two eyes developed rhegmatogenous retinal detachment (both degenerative LMH).
Discussion: This study analyzed the functional and anatomical outcomes of PPV with membrane peeling in degenerative and tractional LMH. There were significant visual acuity improvements in both subgroups and higher rates of anatomical improvement in the tractional subgroup compared to the degenerative subgroup.
Limitations: the baseline characteristics of both groups were statistically different, specifically baseline BCVA and rates of outer-retinal disruption, which may have caused a difference in their outcomes.
Conclusion: PPV with membrane peeling improved best-corrected visual acuity in both degenerative and tractional LMH, with improvement in microanatomy. The study highlights the pathophysiological difference between the two subtypes and supports the clinical distinction between tractional and degenerative LMH.