Long-term outcomes of sural nerve vertical cross-face graft for lacrimal gland neurotization in neurodeprivative dry eye

Purpose: We recently described a novel surgical procedure to reinnervate the lacrimal gland in neurodeprivative dry eye disease and reported the 1-year outcomes of patients treated accordingly. The purpose of this paper is to describe the long-term outcomes of this innovative surgical technique. Methods: Monocentric cross-sectional study including consecutive patients affected by facial palsy with an absolute deficiency of tear secretion (Schirmer test 0 mm/5 min) who underwent lacrimal gland neurotization, as previously described. Before surgery (T0) and at the last follow-up visit (T1), the following parameters were evaluated: tear film break-up time (TBUT), corneal fluorescein staining (Oxford score), Schirmer test type I, usage of tear substitutes (daily number of instillation). At T1, subjective satisfaction with surgery was collected and tear film osmolarity (TFO) was measured in both operated and contralateral eye. Corneal sensitivity was performed at T0 and T1 in patients who underwent neurotization of both lacrimal gland and cornea due to the concomitant presence of neurotrophic keratopathy (trigeminal nerve palsy). Results: Data from 9 patients (4 M, 5 F; mean age 47.1 ± 17.1 years) who underwent lacrimal gland neurotization and were followed up for an average time of 87 months (± 15) (range 60–108) were analyzed. The study procedure was combined in all cases with facial reanimation, while corneal neurotization was performed in 4 cases. At T1, the mean value of Schirmer test was significantly higher compared to T0 (5.8 ± 2.0 vs 0 ± 0 mm/5 min; p < 0.0001). TBUT and corneal fluorescein staining were significantly better compared to baseline (respectively, 2.4 ± 1.8 vs 1.2 ± 0.6 s, p = 0.04 and 1.7 ± 0.8 vs 3.1 ± 0.6, p = 0.0004). TFO was not significantly different between operated eye and contralateral one (306.7 ± 9.5 mOsm/L vs 308.9 ± 11.3 mOsm/L, p = 0.67). The mean daily number of tear substitute instillations was lower at T1 compared to T0 (12 ± 7 vs 21.8 ± 4.3; p = 0.011). Overall, all patients were satisfied with surgery at T1 (very satisfied: n = 3 and satisfied: n = 6). No major postoperative complications were recorded throughout the entire follow-up. Conclusion: Lacrimal gland neurotization through the sural nerve is a safe and effective procedure with stable favorable outcomes in the long term.