Triological Society Best Practice
Is sialendoscopy an effective treatment for obstructive salivary gland disease?
The authors have no funding, financial relationships, or conflicts of interest to disclose.
Send correspondence to Rahmatullah Rahmati, MD, Department of Otolaryngology–Head and Neck Surgery, Columbia University Medical Center, 180 Fort Washington Ave, HP 8-818, New York, NY 10032. E-mail: firstname.lastname@example.org
The management of inflammatory salivary gland disease is undergoing a paradigm shift due to the use of sialendoscopy, which facilitates minimally invasive gland-sparing therapeutic procedures. Although salivary gland resection (sialadenectomy) continues to play an important role in the treatment of significant inflammatory salivary gland disorders due to stones, strictures, and chronic sialadenitis, it is not without potential complications including bleeding, infection, nerve injury, sialocele, and cosmetic deformity.
Sialendoscopy involves miniaturized semirigid endoscopes that allow for the diagnostic evaluation of the salivary ductal system. The working channel of therapeutic endoscopes allows insertion of wire baskets, microforceps, manual drill burrs, laser fibers, and balloons that can be used to address obstructive disorders such as sialoliths and strictures. Additionally, saline irrigation and steroid instillation help to clear cellular debris, salivary sludge, mucous plugs, and generalized ductal inflammation. As such, sialendoscopy offers both diagnostic and therapeutic benefits for obstructive salivary gland disease. This review will evaluate the diagnostic and therapeutic outcomes of sialendoscopy as a single-treatment modality for obstructive salivary gland disease and also identify factors predictive of treatment success.
Sialolithiasis is the main cause of obstructive salivary gland disease. Diagnosis can be made clinically and with a number of imaging modalities such as occlusal view radiographs, computed tomography (CT) scan, ultrasound, contrast sialography, and magnetic resonance sialography. Each imaging modality has its advantages and disadvantages. CT scan, however, provides the best information regarding the size, location, and number of stones. This information is useful in management planning.
Diagnostic sialendoscopy allows the direct visualization and localization of intraductal pathology. In 450 diagnostic sialendoscopy cases, Marchal and Dulguerov had a 98% success rate. Also, in a large study involving 1,154 patients treated with gland-preserving salivary gland surgery by Zenk et al., diagnostic sialendoscopy failed to demonstrate stones in 7% of submandibular and 21% of parotid cases, where stones were suspected on ultrasound, thereby supporting the diagnostic sensitivity of sialendoscopy. For small accessible stones, direct evaluation of the duct with sialendoscopy may obviate the need for imaging studies.
Just as diagnostic sialendoscopy has demonstrated high efficacy rates, interventional sialendoscopy yields comparable results in appropriately selected patients. A recent systematic review and meta-analysis by Strychowsky et al. examined the outcomes of sialendoscopy used in treating obstructive salivary gland disease. The analysis included 19 peer-reviewed articles involving 1,213 patients undergoing a sialendoscopy-alone procedure for their disorder. Success, defined as symptom free or absence of residual obstruction, was obtained in 86% of patients.
The recently published series by Zenk et al. was not included in the above meta-analysis and review, but also reported high stone and symptom-free success rates of 100% and 98% for sialendoscopy-alone submandibular and parotid cases, respectively. The study consisted of 1,154 patients in whom sialolithiasis was diagnosed with sialendoscopy and then approached by different gland-preserving techniques (sialendoscopy, transoral excision, extracorporeal shockwave lithotripsy, or combined approaches) based on stone size, mobility, and/or ability to mobilize the stone. Due to generally larger-sized stones, the majority of submandibular ducts stones were approached through a transoral excision (mean stone diameter, 9.1 mm), whereas only 5% were amenable to a sialendoscopy-alone approach (mean stone diameter, 4.9 mm). Unlike submandibular stones, approximately 50% of the patients with parotid stones were managed with a sialendoscopy-alone or sialendoscopy-assisted procedure. Transoral stone extraction was avoided to prevent stricture formation. Long-term success was >90% for patients with submandibular and parotid stones treated with sialendoscopy.
Luers et al. looked at prognostic factors predicting successful outcomes in sialendoscopy for sialolithiasis and found that size, good mobility, round or oval shape, and distal location in the main salivary duct were positive predictors. Stone size <5 mm resulted in an 80% removal rate, with 91% of stones <4 mm successfully removed. On multivariate analysis, stone mobility was the greatest predictor of successful endoscopic extraction (92%) (Table 1).
Table 1. Gland-Specific Outcomes and Factors Predictive of Success
|Interventional: stone and/or symptom free||86%–100%||86%–98%|
|Size||≤5 mm||≤4 mm|
|Shape||Round or oval||Round or oval|
|Location||Hilum or distal duct||Hilum or distal duct|
|Complications||Procedure failure main minor complication; no permanent nerve injury|
In terms of complications, the Strychowsky et al. meta-analysis found complications to be primarily minor. No cases of permanent nerve injury were reported. Sialoadenectomy rates ranged from 0% to 11% of patients, with a decreasing prevalence in more recently reported series. In a study of 450 patients by Marchal and Dulguerov, there were no cases of nerve injury, hemorrhage, or major salivary duct perforation. They reported cases of minor ductal injury leading to floor of mouth swelling and eight cases involving technical issues with the basket.
Walvekar et al. reported a 25% complication in their series of 56 consecutive patients. Only one patient suffered a major complication involving an avulsion of the parotid duct, which required a superficial parotidectomy. The other complications, which were minor, were mainly due to failure to retrieve the stone or failure to complete the procedure. Stone size and difficulty with navigation of the scope through the duct were the main reasons for failure. Theses authors highlight a greater occurrence of complications in the early phases of the learning curve with sialendoscopy.
Diagnostic sialendoscopy is highly effective in identifying sialolithiasis in obstructive salivary gland disease. Endoscopic findings of round or oval mobile stones <4 to 5 mm generally permit utilization of interventional sialendoscopy in a safe and efficacious, minimally invasive, gland-sparing manner. Large palpable submandibular duct stones or intraglandular stones may be approached with traditional transoral excisional techniques or sialoadenectomy, whereas large intraparotid stones may be managed with a sialendoscopy-assisted approaches or usual conservative means.
LEVEL OF EVIDENCE
Outcomes of obstructive salivary gland disease treated with sialendoscopy are based on level 2a evidence (systematic review of cohort studies). Retrospective institutional experiences represent level 4 evidence (case series).