Periocular Mass Due to Persistent Secretion Within a Transplanted Parotid Duct.

A male patient underwent microvascular transplantation of an autologous submandibular gland and its associated (Wharton's) duct for management of very severe right keratoconjunctivitis sicca due to Stevens-Johnson syndrome; due to hypersecretion, the gland was later removed in toto. Twenty-two years later, he presented with a nontender, sausage-like mass lying subcutaneously in the right temple. Intraoperatively a fluctuant tubular mass passing from the temporalis fossa to the superotemporal conjunctiva was identified and excised intact. Histology showed a slightly proteinaceous fluid within a duct lined with cuboidal epithelium, this being compatible with Wharton's duct. This case highlights that iatrogenic causes should be considered with any history of periocular injury or surgery.

Characteristics and management of vascular compromise after an organ transplantation surgery of the head and neck region: Analysis of 220 submandibular glands with autologous transplantation.

BACKGROUND: Microvascular submandibular gland transplantation (SMGT) for severe dry eye disease (DED) has rarely been reported in the literature. The aim of this study was to report a case series of SMGT with the special focus on monitoring and management of postoperative vascular compromise. METHODS: Using a retrospective single-cohort study design, the investigators enrolled a sample of DED patients undergoing SMGT in a Chinese university hospital during 1999 and 2021. The main outcomes were baseline and surgical data, post-operative manifestations, and surgical results. Descriptive, uni- and bivariate statistics were computed with the significant P < 0.05. RESULTS: During the study period, 220 DED patients (55.9% female) with a mean age of 32.66±14.47 years underwent SMGT. Vascular compromises occurred in 27 grafted glands (12.3%; 22 venous compromises and 5 arterial compromises) at a median of 27 h(range, 3.3 to 288 h) after surgery. Harden texture and swelling of the covering skin flap of the donor indicated venous compromises, while some specific sign was absent for arterial compromise. The accompanying vein of the facial artery (FAV) as a donor's vein was associated with less vascular compromise compared to the anterior facial vein (AFV). Timely reexploration was performed in 25 glands (92.6%), with a salvaged rate of 48%, and more venous compromises were salvaged compared to artery compromises (54.6% vs. 0%, P = 0.047). Temporary hypersecretion on postoperative 2-5 days was noticed in the grafted glands with no or salvaged vascular compromise (Schirmer's test, 35 mm/5 min and 37 mm/5 min, respectively, P = 0.749), while they were absent for the 15 surgically failed grands (Schirmer's test 0 mm/5 min, P<0.001). CONCLUSIONS: Vascular compromise appears to be a common complication of SMGT. Postoperative hypersecretion of the grafted glands may indicate good circulation, and the use of FAV as the donor's vein could help to decrease the risk of vascular compromise.

Sex-dependent Regeneration Patterns in Mouse Submandibular Glands.

Our previous studies indicated that YIGSR-A99 peptides chemically conjugated to fibrin hydrogel (FH) and applied to wounded submandibular gland (SMG) in vivo, formed new organized salivary tissue, whereas wounded SMG treated with FH alone or in the absence of a scaffold showed disorganized collagen formation and poor tissue healing. While these studies indicated that damaged SMG grow and differentiate when treated with FH containing L1 peptide, they were performed only in female mice. However, there is a well-established sexual dimorphism present in mouse SMG (e.g., males develop well-differentiated granular convoluted tubules, but these structures are poorly developed in females) and little is known about how these sex differences influence wound healing events. Therefore, the goal of this study was to conduct comparative analyses of regeneration patterns in male and female mice using L1p-FH in a wounded SMG mouse model. Particularly, we focused on sex-dependent wound healing events such as macrophage polarization, vascularization, tissue organization, and collagen deposition, and how these events affect salivary gland functioning.

Anomalous Course of Facial Artery Through the Submandibular Gland and its Redundant Loop at the Base of Mandible.

Knowledge of variant course and branching pattern of the facial artery gains importance in the surgeries of upper neck and face. The authors report a unilateral anomalous course and a redundant loop of right facial artery as seen in an adult male cadaver. The right facial artery had its origin from the external carotid artery. It pierced through the submandibular salivary gland and formed a redundant loop at the base of the mandible. Its further course and branching pattern was normal. This case could be important for radiologists, plastic surgeons and craniofacial surgeons.

[MICRO- AND ULTRASTRUCTURAL RECONSTRUCTION OF THE RAT SUBMANDIBULAR GLAND IN THE LATE STAGES OF EXPERIMENTAL TYPE 2 DIABETES MELLITUS].

Electron microscopic investigations of the animals' submandibular gland, conducted in 6 weeks of the experiment, established that ultrastructural changes increase in glandular cells of terminal secretory units in comparison with early period of the experiment. Serocytes have osmiophilic, rather small or picnotic nuclei. Perinuclear spaces of karyolemma are uneven, external nuclear membrane forms local protrusions. Electron density of the karyoplasm is significant, appearing homogenous, nuclei are not observed. Evident submicroscopic changes in blood capillaries of the submandibular gland in experimental diabetes mellitus indicate the impairment of blood-tissue barrier and transcapillary exchange. Deep destructive modifications of all branches of microcirculatory blood flow of the submandibular gland are observed in 8-week course of experimental diabetes mellitus. As compared with the 6th week of investigation, a reliable slight dilation of organ artery diameter, dilation of the diameter of interlobular arterioles, dilation of the diameter of intralobular (precapillary) arteriole and dilation of the capillary diameter were observed. Dilation, as compared to 6th weeks of the experiment, of postcapillary venules was observed. Compared to the indices of the 6th weeks of the experiment, an index of trophic activity of the submandibular gland tissuereaches its maximum meaning and an index of packing density of the capillaries reaches its minimum meaning. Capillary network loses delicate, tortuous pattern and often breaks due to destruction of the capillary component. Arteriovenous anastomoses dilate and blood from the arterioles flows into the venous bed avoiding destructed capillaries. Venules are dilated; thin-walled, retained fragments of the capillaries are significantly dilated in some areas. Swelling of connective tissue stroma and significant swelling of the interstitium are observed. Walls of the capillaries and venules are deformed. The walls of the arterioles are thickened due to plasmorrhagia, sclerosis and hyalinosis.

A Novel Experimental Approach for In Vivo Analyses of the Salivary Gland Microvasculature.

Microvascular dysfunction plays a fundamental role in the pathogenesis of salivary gland disorders. Restoring and preserving microvascular integrity might therefore represent a promising strategy for the treatment of these pathologies. The mechanisms underlying microvascular dysfunction in salivary glands, however, are still obscure, partly due to the unavailability of adequate in vivo models. Here, we present a novel experimental approach that allows comprehensive in vivo analyses of the salivary gland microvasculature in mice. For this purpose, we employed different microscopy techniques including multi-photon in vivo microscopy to quantitatively analyze interactions of distinct immune cell subsets in the submandibular gland microvasculature required for their infiltration into the surrounding parenchyma and their effects on microvascular function. Confocal microscopy and multi-channel flow cytometry in tissue sections/homogenates complemented these real-time analyses by determining the molecular phenotype of the participating cells. To this end, we identified key adhesion and signaling molecules that regulate the subset- and tissue-specific trafficking of leukocytes into inflamed glands and control the associated microvascular leakage. Hence, we established an experimental approach that allows in vivo analyses of microvascular processes in healthy and diseased salivary glands. This enables us to delineate distinct pathogenetic factors as novel therapeutic targets in salivary gland diseases.

Natriuretic peptide system expression in murine and human submandibular salivary glands: a study of the spatial localisation of ANB, BNP, CNP and their receptors.

The natriuretic peptide (NP) system comprises of three ligands, the Atrial Natriuretic Peptide (ANP), Brain Natriuretic peptide (BNP) and C-type Natriuretic peptide (CNP), and three natriuretic peptide receptors, NPRA, NPRB and NPRC. Here we present a comprehensive study of the natriuretic peptide system in healthy murine and human submandibular salivary glands (SMGs). We show CNP is the dominant NP in mouse and human SMG and is expressed together with NP receptors in ducts, autonomic nerves and the microvasculature of the gland, suggesting CNP autocrine signalling may take place in some of these glandular structures. These data suggest the NP system may control salivary gland function during homeostasis through the regulation of electrolyte re-absorption, neural stimulation and/or blood vessel wall contraction/relaxation. We also show abnormal expression of NPRA in the stroma of a subset of human SMGs resected from patients diagnosed with oral squamous cell carcinoma (OSCC) of non-salivary gland origin. This finding warrants further research to investigate a possible correlation between early OSCC invasion and NPRA overexpression.

Arteriovenous vascular malformation of the submandibular gland masquerading as Küttner's tumour.

Chronic sclerosing sialadenitis, also known as Küttner's tumour, is a chronic inflammatory condition affecting the salivary glands. We present the case of an arteriovenous vascular malformation (AVM) of the right submandibular gland mimicking a Küttner's tumour on ultrasound scan in a 63-year-old woman. Examination revealed a 2 cm firm, mobile, non-pulsatile, right-sided submandibular mass with no overlying skin changes but with mild tenderness to palpation. Histological appearances revealed an AVM associated with localised fatty metaplasia and glandular atrophy. Although rare, AVMs should be considered a differential diagnosis for a submandibular gland mass that gives unclear or unusual radiological appearances.

Microvascular Submandibular Gland Transplantation for Severe Keratoconjunctivitis Sicca: A Single-Institution Experience of 61 Grafts.

PURPOSE: Keratoconjunctivitis sicca (KCS) is a relatively common disease that results in discomfort, tear film instability, visual impairment, and ocular surface damage. Artificial tear substitutes may be suitable for the treatment of mild KCS, but no effective treatment currently exists for severe KCS. Therefore, this study evaluated the effectiveness of autologous microvascular submandibular gland transplantation in the treatment of severe KCS. PATIENTS AND METHODS: A total of 61 eyes (56 patients) with severe KCS were treated with autologous submandibular gland transplantation from June 2002 to June 2017. The cephalic vein or the great saphenous vein was applied to solve the problem of unmatched veins. RESULTS: In 53 cases (53 of 56, 94.6%), 58 glands (58 of 61, 95.1%) were transplanted successfully. The mean Schirmer I test value improved from 0.78 ± 0.84 mm preoperatively to 18.83 ± 5.72 mm in the stable period after transplantation. Epiphora (14 of 58, 24.14%) was the most common complication of this procedure. Other postoperative complications included venous thrombosis (6 of 61, 9.84%), local infection (2 of 58, 3.45%), xerostomia (2 of 53, 3.77%), duct fistula (1 of 58, 1.72%), sialolithiasis (1 of 58, 1.72%), and ranula (1 of 58, 1.72%). CONCLUSIONS: Autologous microvascular submandibular gland transplantation is a credible and effective solution for severe KCS.

A Surgical Approach to the Harvest of the Vascularized Submandibular and Submental Lymph Node Flap: The "Through-the-Gland" Dissection Technique.

BACKGROUND: Extremity lymphedema is a pathological condition resulting from absence of lymph nodes and disease of lymphatic vessels, often due to oncologic clearance of lymph nodes. In recent years, vascularized lymph node transfer has become a rapidly emerging method of lymphatic reconstruction shown to lead to lymphatic regeneration. In particular, lymphatic flaps based on the submental artery have shown good results with its favorable donor site and available nodes. The lymph nodes here are in close relation to the submandibular gland and require careful dissection around and through the gland for safe harvest. We studied this region of the neck and describe the blood supply to the lymph nodes, their variable positions in relation to the gland, and our technique of dissecting through the submandibular gland while keeping the lymph nodes' hilar blood supply intact. METHODS: We dissected 2 cadaver heads (4 sides of the neck) to study the submandibular and submental lymph nodes, where to locate them in relation to the submandibular gland and how best to dissect through the submandibular gland for access while keeping the hilar supply intact. We applied this knowledge in 6 clinical cases and provide a brief description of our "through-the-gland" dissection technique. RESULTS: The submandibular lymph nodes may lie (1) superficial and posterior to the gland, (2) between the superficial and deep parts of the submandibular gland, or (3) anteriorly and submental. They are classified as superficial, deep, and submental, respectively. The through-the-gland dissection technique gave the surgeon improved access and exposure to the lymph nodes. It also facilitated safer dissection because their hilar blood supply is well visualized. CONCLUSIONS: The through-the-gland technique of harvesting vascularized submandibular lymph node flaps is a safe technique that allows the surgeon to clearly identify and preserve blood supply of lymph nodes.

Differences in salivary secretory function between patients with erosive esophagitis and those with nonerosive reflux disease.

BACKGROUND AND AIM: It has been speculated that impaired salivary flow contributes to abnormal acid clearance in patients with erosive esophagitis (EE). For easy and objective assessment of salivary function, we developed a salivary gland blood flow measurement technique using continuous-wave Doppler sonography. In the present study, we evaluated the salivary secretory function in patients with EE and those with nonerosive reflux disease (NERD) using this method. METHODS: Doppler waveform analysis was performed on the facial artery to assess blood inflow to the submandibular gland of 30 healthy subjects (HS). Blood flow was compared before and after secretory stimulation with 1 mL of lemon juice. Saliva was simultaneously collected and weighed before and after stimulation. Continuous-wave Doppler sonography was also performed in patients with EE and NERD. The size of the submandibular gland was compared in 26 patients with EE, 41 patients with NERD, and 86 HS. RESULTS: The submandibular gland blood flow increased after stimulation in all HS. Both within-day and day-to-day reproducibility were good. There was a significant correlation between the percent increase in the maximum velocity and the percent increase in salivary secretion. Although the size of the submandibular gland was not significantly different among the three groups, the percent increase in the maximum velocity in patients with EE was significantly smaller than that in HS. CONCLUSIONS: We have established an easy method of assessing salivary function in daily practice. This study revealed that a decrease in salivary secretory function is involved in the pathology of EE.

Differences in control of parasympathetic vasodilation between submandibular and sublingual glands in the rat.

We examined blood flow in the submandibular gland (SMGBF) and sublingual gland (SLGBF) during electrical stimulation of the central cut end of the lingual nerve (LN) in the urethane-anesthetized rats using a laser speckle imaging flow meter. LN stimulation elicited intensity- and frequency-dependent SMGBF and SLGBF increases, and the magnitude of the SMGBF increase was higher than that of the SLGBF increase. The increase in both glands was significantly inhibited by intravenous administration of the autonomic cholinergic ganglion blocker hexamethonium. The antimuscarinic agent atropine markedly inhibited the SMGBF increase and partly inhibited the SLGBF increase. The atropine-resistant SLGBF increase was significantly inhibited by infusion of vasoactive intestinal peptide (VIP) receptor antagonist, although administration of VIP receptor antagonist alone had no effect. The recovery time to the basal blood flow level was shorter after LN stimulation than after administration of VIP. However, the recovery time after LN stimulation was significantly delayed by administration of atropine in a dose-dependent manner to the same level as after administration of VIP. Our results indicate that 1) LN stimulation elicits both a parasympathetic SMGBF increase mainly evoked by cholinergic fibers and a parasympathetic SLGBF increase evoked by cholinergic and noncholinergic fibers, and 2) VIP-ergic mechanisms are involved in the noncholinergic SLGBF increase and are activated when muscarinic mechanisms are deactivated.

Brief Report: Ultrasonographic Assessment of Salivary Gland Response to Rituximab in Primary Sjögren's Syndrome.

OBJECTIVE: To evaluate changes in salivary gland echostructure and vascularization after rituximab treatment in patients with primary Sjögren's syndrome (SS). METHODS: Twenty-eight patients with primary SS included in the multicenter, randomized, double-blind, placebo-controlled Tolerance and Efficacy of Rituximab in Primary Sjögren's Syndrome (TEARS) trial underwent salivary gland ultrasonography before the first placebo or rituximab infusion and then 6 months later. Trial inclusion criteria were scores of ≥50 mm on at least 2 of 4 visual analog scales (VAS) evaluating dryness, pain, fatigue, and global disease; and recent-onset (<10 years) biologically active primary SS and/or systemic primary SS. Patients were randomly assigned (1:1) to rituximab (1 gm at weeks 0 and 2) or placebo. Ultrasonography of both parotid and submandibular glands was performed to assess echostructure (using a semiquantitative score of 0-4, with improvement defined as a ≥1-point decrease), size of each gland, and vascularization based on the resistive index of the transverse facial artery of the parotid gland before and after lemon juice stimulation. RESULTS: Of the 28 patients, 5 (18%; 3 in the placebo group and 2 in the rituximab group) had clinically detectable bilateral parotid gland enlargement at baseline. Parotid parenchyma echostructure improved in 50% of the rituximab-treated patients versus 7% of the placebo-treated patients (P = 0.03). In the submandibular glands, echostructure also improved in a larger proportion of rituximab-treated patients, although the difference was not significant (36% versus 7% of placebo-treated patients; P = 0.16). Gland sizes and resistive index remained unchanged. CONCLUSION: Ultrasonography showed improved salivary gland echostructure in patients with primary SS receiving rituximab, with no changes in salivary gland size or vascularization, 6 months after the first infusion.

Submandibular venous hemangioma: Case report and review of the literature.

Hemangiomas of the submandibular space are very rare. Only 11 cases have been reported in the English literature, all of which were cavernous hemangiomas. In this report, we describe the case of a venous hemangioma in a 70-year-old woman. Ultrasound examination revealed a lobulated, homogeneous, hypoechoic mass, and minimal flow was detected on power Doppler evaluation. The mass and the submandibular gland were surgically excised, and the endothelium was found to be positive for CD31 and D2-40 markers, consistent with venous hemangioma. To our knowledge, this is the first reported case of a venous hemangioma in the submandibular space.

Ischemia preconditioning protects rat submandibular glands from ischemia/reperfusion injuries.

To investigate the effects of ischemia/reperfusion on rat submandibular glands without denervation and the possible protective effects of ischemia preconditioning on the glands that experienced ischemia/reperfusion, in-situ ischemia/reperfusion and ischemia preconditioning experimental models of submandibular glands of healthy male Wistar rats were conducted. For ischemia/reperfusion groups, the glands were subjected to 90 min of ischemia without denervation, followed by 1, 12, 24, or 72 h of reperfusion. Ischemia preconditioning was achieved by 3 min of ischemia following 3 min of reperfusion, performed three times before ischemia/reperfusion. Salivary secretion, histological changes, alterations of tight junctions, myeloperoxidase activity, cellular apoptosis, and reactive oxygen species levels were detected. In ischemia/reperfusion glands, rising acute-inflammation responses, reduced tight-junction width, and increased myeloperoxidase activity, reactive oxygen species levels, and apoptotic cell numbers were observed, along with secretory dysfunction, especially at 1 and 12 h post-reperfusion, which seemed to gradually return to normal by 72 h post-reperfusion. In contrast, ischemia preconditioning showed the potential to ameliorate the injury-stress responses caused by ischemia/reperfusion. Our study revealed that ischemia/reperfusion could cause a series of injury-stress responses and ultimately lead to hyposecretion, independently of the parasympathetic nerve supply, which might play an important role in the early-phase dysfunction of the transplanted glands. Ischemia preconditioning could protect the involved glands and improve ischemia/reperfusion-induced hyposecretion.

Effect of neuropeptide Y on norepinephrine-induced constriction in the rabbit facial artery after carotid artery occlusion.

BACKGROUND/AIM: Atherosclerotic-occlusive changes could be observed in orofacial branches of the external carotid artery. Atherosclerosis-induced ischemia caused alteration in production and release of endothelial factors. The aim of this study was to investigate the influence of carotid artery occlusion (10, 30 and 60 min) on vascular effects of norepinephrine (NOR) and neuropeptide Y (NPY) in the isolated glandular branch of the rabbit facial artery, the main feeding artery for the submandibular gland. METHOD: Changes in isometric tension were recorded in organ bath studies with arterial rings, before and after carotid artery occlusion. RESULTS: Concentration-dependent vasocontractile effect of NOR was significantly augmented after 30 and 60 min of carotid occlusion, but only in the rings with intact endothelium. Given alone, NPY showed no effect in isolated glandular branch of the rabbit facial artery, but enhanced NOR vasoconstriction in all the investigated rings. NOR vasocontractile effect enhancement in the presence of NPY was attenuated after 30 and 60 min of carotid occlusion. Also, enhancement of NOR vasoconstriction by NPY was significantly higher in endothelium-intact rings compared to endothelium-denuded rings obtained after 30 and 60 min of carotid occlusion. CONCLUSION: The present investigation provides results of increased vasocontractile effect of NOR and decreased enhancing effect of NPY on NOR vasoconstriction in the rabbit facial artery after carotid occlusion that is related to altered endothelium function.

Submandibular venous malformation phleboliths mimicking sialolithiasis in children.

OBJECTIVES/HYPOTHESIS: Salivary gland stones (sialoliths) are a common cause of salivary gland enlargement, but such stones are uncommon in children. Low-flow vascular malformations of the head and neck region may develop phleboliths. Phleboliths within a venous malformation may be mistaken for a salivary stone given the similar calcified nature and location. We present two children who were referred to us for evaluation of submandibular gland sialoliths but were found to have venous malformations containing phleboliths. Multiple calcifications, calcifications > 1 cm, within a soft tissue mass separate from the substance of the submandibular gland suggest a diagnosis, of phleboliths within a venous malformation as opposed to a sialolith.

Dynamic contrast-enhanced ultrasound for differential diagnosis of submandibular gland disease.

Intensity-time gradients (ITGs) of contrast-enhanced ultrasound (CEUS) can be used for non-invasive monitoring of gland-preserving treatment effects in sialolithiasis-related chronic sialadenitis as well as for imaging vascularization in tumors. The aim of this clinical trial was to evaluate feasibility to distinguish different entities of submandibular gland disease including inflammatory alterations of the submandibular gland as well as benign and malignant tumors. In this prospective clinical study, ITGs in 30 patients with sialolithiasis-related chronic sialadenitis or an unilateral submandibular mass and 18 disease-free submandibular gland controls were quantitatively analyzed by CEUS using the contrast agent SonoVue. In addition, clinical complaints according to visual analog scales (VAS) were documented. VAS data documented significantly less complaints only in benign tumors compared with the other pathologies of the submandibular gland. In parallel, CEUS-derived ITGs revealed significantly reduced ITGs only in benign tumors (n = 5) compared to the controls (n = 18). Despite of comparably reduced wash-in velocities in malignant lesions (n = 3) statistical significance was not reached. Chronic sialadenitis (n = 18) and its sclerosing variant (Küttner tumor, n = 4) revealed comparable ITGs as controls. Tumors of the submandibular gland present with reduced functional microcirculatory networks comparing with healthy gland controls and chronically inflamed submandibular glands. Thus, dynamic CEUS-derived ITGs in combination with conventional clinical measures--for example VAS--appear as a safe and promising strategy for non-invasive diagnostic workup of submandibular lesions and warrant further validation in a larger set of patients.

Upregulation of aquaporin expression in the salivary glands of heat-acclimated rats.

It is known that aquaporin (AQP) 5 expression in the apical membrane of acinar cells in salivary glands is important for the secretion of saliva in rodents and humans. Although heat acclimation enhances saliva secretion in rodents, the molecular mechanism of how heat induces saliva secretion has not been determined. Here, we found that heat acclimation enhanced the expression of AQP5 and AQP1 in rat submandibular glands concomitant with the promotion of the HIF-1α pathway, leading to VEGF induction and CD31-positive angiogenesis. The apical membrane distribution of AQP5 in serous acinar cells enhanced after heat acclimation, while AQP1 expression was restricted to the endothelial cells in the submandibular glands. A network of AQPs may be involved in heat-acclimated regulation in saliva secretion. Because AQPs probably plays a crucial role in saliva secretion in humans, these findings may lead to a novel strategy for treating saliva hyposecretion.

Microvascular autologous transplantation of partial submandibular gland for severe keratoconjunctivitis sicca.

OBJECTIVE: To evaluate the feasibility of microvascular autologous transplantation of partial submandibular gland (SMG) to prevent or reduce epiphora in severe keratoconjunctivitis sicca (KCS). METHODS: A total of 39 patients with KCS, covering 42 eyes, were randomised to undergo transplantation of partial or total SMG from January 2006 to December 2009. Clinical data of survival rate of transplanted SMG, ophthalmologic features of best-corrected visual acuity, Schirmer test results, break-up time (BUT) of tear film, fluorescence staining, incidence of postoperative epiphora and frequency of subsequent surgery were compared between two groups. RESULTS: Total SMG transplantation was performed in 22 eyes, and partial SMG transplantation was performed in the other 20 eyes. All transplanted SMGs survived. Microvascular crisis occurred in one case of partial SMG transplantation, but the gland survived after exploration to remove the venous thrombus. Obstruction of the ductal orifice in one case of partial SMG transplantation was resolved by reconstruction of the ductal orifice. Symptoms of dry eyes disappeared, and patients were able to discontinue use of artificial tears. Severe epiphora occurred in 6 eyes undergoing partial SMG transplantation and in 19 eyes undergoing total SMG transplantation (p<0.01). Surgical reduction was performed in 6 eyes undergoing partial SMG transplantation and 18 eyes undergoing total SMG transplantation (p<0.01). CONCLUSIONS: Microvascular transplantation of partial SMG is feasible and effective for severe KCS and does not decrease the survival rate of transplanted SMG. For ample SMGs with normal function, transplantation of partial SMG alleviates the symptoms of dry eye and significantly reduces the incidence of severe postoperative epiphora.