Effects of Capsaicin and Carbachol on Secretion From Transplanted Submandibular Glands and Prevention of Duct Obstruction

Salivary Gland Transplantation as a Promising Approach for Tear Film Restoration in Severe Dry Eye Disease

With increased awareness of dry eye disease (DED), a multitude of therapeutic options have become available. Nevertheless, the treatment of severe DED remains difficult. In a patient whose DED is related to the loss of lacrimal function without severe destruction of the salivary glands, autologous transplantation of the latter as functioning exocrine tissue to rebuild a stable tear film is an attractive idea. All three major and minor salivary glands have been used for such transplantation. Due to the complications associated with and unfavorable prognosis of parotid duct and sublingual gland transplantation, surgeons now prefer to use the submandibular gland (SMG) for such procedures. The transplantation of the SMG not only has a high survival rate, but also improves dry eye symptoms and signs for more than 20 years post-surgery. The regulation of the secretion of the transplanted SMG is critical because the denervated SMG changes its mechanism of secretion. Innovative procedures have been developed to stimulate secretion in order to prevent the obstruction of the Wharton's duct and to decrease secretion when postoperative "epiphora" occurs. Among the minor salivary glands, the transplantation of the labial salivary glands is the most successful in the long-term. The measurement of the flow rates of minor salivary glands and donor-site selection are critical steps before surgery.

Submandibular Gland Transplantation vs Minor Salivary Glands Transplantation for Treatment of Dry Eye: A Retrospective Cohort Study

PURPOSE

To compare submandibular gland (SMG) transplantation with minor salivary gland (MSG) transplantation for the treatment of different dry eye diseases (DED).

DESIGN

Retrospective clinical cohort study.

METHODS

A total of 73 refractory DED eyes were divided into 3 groups. Group A comprised 35 end-stage DED eyes that underwent SMG transplantation. Group B comprised 20 end-stage DED eyes with MSG transplantation. Group C comprised 18 non-end-stage DED eyes with MSG transplantation. Schirmer test (ST), tear break-up time (TBUT), corneal fluorescein staining (FL), and best-corrected visual acuity (BCVA) were measured before and after surgery.

RESULTS

Hospital length of stay, length of operation, and hospital fee were significantly higher in group A than in group B or C. Eyes in group A showed the most severe DED disease, with preoperative ST, TBUT, FL, and BCVA of 0.36 mm per 5 minutes, 0.03 seconds, 10.97, and 0.11, respectively, which improved significantly to 20.23 mm per 5minutes, 1.74 seconds, 7.58, and 0.2 at >2-year follow-up. Group B had similar baseline data, and significant but limited improvement only in the ST (0.55 mm per 5 minutes to 3.79 mm per 5 minutes) and FL (11.10 to 9.58) after the operation. Group C had better baseline ST, TBUT, FL, and BCVA of 0.89 mm per 5min, 3.49 seconds, 1.83, and 0.81, respectively, which improved significantly (except for BCVA) to 9.35 mm per 5min, 9.08 s, 0.53, and 0.89 after MSG transplantation.

CONCLUSION

SMG transplantation could be recommended to treat end-stage refractory DED. MSG transplantation may provide satisfying results for refractory DED with relatively less severe impairment of the eye.

Management of duct obstruction in transplanted submandibular glands

BACKGROUND

Submandibular gland (SMG) transplantation is a successful treatment approach for patients with severe dry eye. However, duct obstruction can occur post-transplant.

METHODS

We studied nineteen patients with duct obstruction of transplanted SMGs, including five interventional modalities: stone removal; secretory stimulation (to mimic "internal irrigation" with substantial secretory flow); irrigation; surgical opening of stenosis and orifice reconstruction; cephalic vein bypass and Wharton's duct reconstruction.

RESULTS

A solitary stone was found and removed in one patient. Duct blockages like mucus plug were cleared by secretory stimulation in three patients, and by normal saline irrigation in two grafts. In the remaining 13 patients, irrigation failed and surgical opening was performed. Orifice reconstruction succeeded in six of the eight patients, whose stenosis was near the orifice. Wharton's duct reconstruction was successful in two of the five cases where stenosis was located in the middle segment of the duct.

CONCLUSION

Transplanted SMGs obstruct for various reasons. Stone, which is easy to diagnose and treat, should be excluded first. Non-organic blockage and stenosis were semblable in clinic. Therefore, subsequent steps should be a diagnostic/therapeutic trial of secretory stimulation, followed by irrigation; failure of these interventions suggests the diagnosis of duct stenosis, necessitating surgical recanalization.