Transplantation of labial salivary glands can be a more fundamental solution in cases of severe dry eyes when even frequent eye drop instillations only give partial relief of symptoms. The glands are easily accessible and their secretion product is very similar to natural tears. I use the labial glands of the lower lip. These form a group of lobula that are so numerous, they form an almost compact layer between the quadratus labii muscle and the oral mucosa. Each lobule is approximately 2 mm by 2 mm by 3 mm and has a short excretory duct that exits in the oral cavity. The secretion of these labial glands is mixed mucoserous and very similar to the composition of natural tears but more viscous. Its lipid level is four to five times greater than in other salivary glands. This aspect makes it suitable to replace natural tears. The technique of transplanting labial salivary glands was first described by Prof. Juan Murube del Castillo. I modified the protocol and use the Ellman high-frequency/low-temperature radiosurgical equipment. For this particular intervention I use the cut-coagulate mode, which gives 50% cutting and 50% coagulation. The small coagulation effect limits the bleeding of the highly vascular mucosa. With Radiosurgery mucosa and salivary glands can be excised without damaging the firm glandular structures or the quadratus labii muscle.

All surgery is performed under general anesthesia. First the recipient beds in both upper and lower lid of one eye are prepared. The lid is everted using a Desmarres lid retractor. Xylocaïne 1% solution with epinephrine is injected under the tarsal conjunctiva to separate it from the underlying Mueller's muscle in the upper lid or retractor muscle in the lower lid. The epinephrine causes a local vasoconstriction to (further) limit the bleeding. Next, an incision of approximately 2.5 cm is made along the rim of the tarsal plate using a fine wire electrode and using the cut/coagulation setting of the Radiosurgical unit. In this way, the conjunctiva is dissected posteriorly for approximately 1.5 cm. When the lid retractor is removed we can switch to the lower id of the same eye and repeat the procedure. The inferior lip is then everted with two 4-0 silk sutures, entering the inner aspect of the lip rim and exiting through the inner aspect again but 1 cm more laterally. Applying traction to these sutures, the inner, mucosal side of the lip can be exposed, facilitating the taking of the grafts. A first horizontal incision is made in the lip mucosa, not closer than 1 mm from the mouth opening and staying 0.5 cm laterally to the midline of the lip and ending 2 cm to 2.5 cm more laterally. Histoloical studies confirm that fewer glands are found in the central third part of the lower lip; they are more numerous in the lateral portions of the lip. Two vertical incisions are then made from the end of the horizontal incisions in the direction of the gingivo-labial sulcus. I cut through the complete mucosa thickness without going too deep i.e. without damaging the quadratus labii muscle. The use of Radiosurgery also facilitates careful dissection of the lip mucosa with the attached salivary lobules from the underlying muscle. The resulting labial wound is cleaned with a Polyvidone solution and left with no cover. I never suture this labial wound. It easily granulates in the days after surgery. The obtained donor piece is cut in two fragments, carefully avoiding damaging any of the glandular structures and, of course, not bisecting any of the lobules. The upper lid is everted again with the Desmarres retractor, and the donor piece is carefully sutured to the receptor site. Each graft is held in place with two horizontal running submucosal prolene 4/0 sutures (Fig!) The Prolene enters the eyelid through the skin temporally, runs submucosally along the superior border of the graft to the nasal side (Fig??) where it re-emerges from the skin. In a similar way the inferior border of the graft is sutured. At the end, both external cut ends of the prolene are tied together on the skin. (Fig.??) The same technique is the used for the lower lid. I always try to maintain as many lobules as possible, and if any salivary glandule pops out during the suturing, it is reintroduced with a blunt instrument (forceps without teeth, strabismus hook,..) The area is rinsed by a 10% polyvidone solution. A lightly compressive bandage is placed over the treated eye and checked 24 hours postop. At this time the eye is gently rinsed with antibiotic drops and a new bandage is placed over the operated eye. Next checkups are done 4, 7 and 14 days postop. At this time the prolene sutures can already be removed. Further controls are done, depending on the individual results of the healing.

Postop clinical course The day after surgery, the graft looks rather pale and we can see a variable degree of chemosis. All patients have conjunctivitis to some extent during the days after the operation. When we change the bandage, secretions are gently wiped off with a wet cotton tip. During the first week I prefer to put a bandage under light pressure to prevent any bleeding that could influence the survival of the graft. After one week we already notice a vascularization of the graft, and after 2 weeks a secretion of saliva can easily been seen. The 15th day is also the day that the sutures can be removed. In the beginning, the secretion product seems to be more viscous than normal tears, but one month later no difference in appearance with natural tears can be noticed.

Results The donor site for the mucosal graft heals without any further treatment, although local hypo-esthesia of the mucosal part of the lip can persist for a few months. Even in the immediate postop period, the patients report only minor discomfort. Despite the use of polyvidone solution at the end of the operation all patients have bacterial conjunctivitis to some extent. All the grafts had a whitish color during the first postop week. Sometimes the transplant has a violet color in some areas, caused by a local submucosal bleeding. After 1 week, when the eyes are left open, i.e., without a bandage, patients usually already report some subjective improvement. Multiple test confirm the subjective improvement of the patients.

Evolution The pathologist reported the persistence of normal acinar tissue in biopts taken after 18 and 36 months.

Cconclusion: although more study has to be done to confirm my results, the first 18 cases are very promising and patients' acceptance is excellent. The procedure is easy with only minimal surgical risk. Radiosurgery makes an important contribution to facilitation of the surgery and survival of the graft.