Medical Policy

Policy Num:   07.001.170
Policy Name: Lithotripsy for Salivary Stones
Policy ID:       [07.001.170] [Ac / L / M+ /P+] [0.00.00]

Last Review:  October 24, 2024
Next Review: October 20, 2025
 

Related Policies:  07.001.034 Extracorporeal Shock Wave Lithotripsy (ESWL)

Lithotripsy for Salivary Stones

Summary

The major salivary glands, parotid (front and behind the ear), submandibular (both sides of the jaw), and sublingual glands (beneath the tongue), are located near the mouth and throat. Their function is to secrete saliva into the mouth aiding in digestion, moistening the mouth, and protecting teeth from decay. There are also approximately 600 to 1,000 small glands, called minor salivary glands and they are 1-2mm in diameter. They coat all the mucosa surface around the mouth and throat. Sialolithiasis is the most common cause of ductal obstruction of the major salivary glands. Salivary stones or Sialolithiasis are developed when chemicals, debris, and calcium build-up from a small rock or "stone" and it becomes lodged or stuck on the salivary duct. The shape and size of these stones vary and may be asymptomatic. In some patients, these stones may present the following symptoms: pain, swelling, difficulty eating or swallowing, inflammation, and infection. 

Extracorporeal shock wave lithotripsy (ESWL) is a minimally invasive approach that uses high-energy shock waves generated outside the body to pulverize or crush the stones inside the body. ESWL consists of high-intensity shock waves that are produced electrically, and focused radiographically or ultrasonically on the treatment area. Intra-corporeal lithotripsy exploits the shock waves generated by a lithotripsy probe that is inserted into the salivary duct system under endoscopic guidance and directly reaches the stone's surface. More than one treatment may be required. 

Objective

The objective of this evidence review is to examine whether the use of extracorporeal or intra-corporeal shock wave treatments for sialolithiasis improves the net health outcome.

Policy Statements

Intraductal Shockwave lithotripsy (ISWL) may be considered medically necessary as a combination approach in selected cases of sialolithiasis. 

Extracorporeal Shock Wave Lithotripsy (ESWL - 50590) is considered investigational for the treatment of salivary stones, as is not approved by the US Food and Drug Administration (FDA) for this use.

Policy Guidelines

Coding

Please see the Codes table for details.

Benefit Application

BlueCard/National Account Issues

State or federal mandates (eg, Federal Employee Program) may dictate that certain U.S. Food and Drug Administration‒approved devices, drugs, or biologics may not be considered investigational, and thus these devices may be assessed only by their medical necessity.

Benefits are determined by the group contract, member benefit booklet, and/or individual subscriber certificate in effect at the time services were rendered.  Benefit products or negotiated coverages may have all or some of the services discussed in this medical policy excluded from their coverage.

Background

Introduction

Sialolithiasis is a benign condition that involves the hardening of mineral deposits formed in the salivary glands. Out of all the glands located on the mouth, the major salivary glands are the parotid, submandibular, and sublingual glands. Mineral stones form on the ducts of these glands and are the most frequent cause of salivary gland swelling, with a reported incident of 1 in 10,000 to 1 in 30,000. Sialolithiasis leads to inflammation, and in some cases, a bacterial infection that leads to abscess. The most common symptoms are postprandial swelling of the affected gland and decreased salivary flow.

Etiology

Since the incidence of Sialolithiasis is so rare, extensive studies have been limited, so there are no established etiologic factors of the disease. Possible causes are associated with dehydration, illness, medications, anticholinergic drugs, trauma, smoking, and gum disease.

Epidemiology

The primary age of diagnosis is between 30 and 60 years old, with a higher incidence in males. Approximately 85% of sialoliths occur within the submandibular gland, making it the most common location for sialolithiasis. One of the reasons is that the submandibular duct ascends towards its opening in the oral cavity, resulting in a stagnant flow of saliva. Additionally, the submandibular gland produces predominately mucinous saliva, which is more viscous than the secretions created by the parotid gland, resulting in a more stagnant flow of secretions. The submandibular gland also produces more alkaline saliva, which predisposes to precipitation of inorganic salts (i.e., calcium and phosphate), further leading to salivary stone formation. Approximately 15% of salivary stones occur within the parotid gland, and less than 5% occur within the sublingual and minor salivary glands. 

Pathophysiology

The exact pathogenesis of sialolithiasis is not well understood, but two dominant theories were suggested: multiple internal microcalculi within salivary gland secretory granules that act as nidus for the formation of larger calculi, and bacteria or food debris within the oral cavity that enter the ducts and act as nidus for the formation of the calculi.

Diagnosis

Sialolithiasis may be asymptomatic in some patients, making it difficult to detect, unless the stones obstruct the salivary ducts. Most commonly, the patient will present with unilateral salivary gland swelling of acute onset, pain that worsens during meals, asymmetric swelling of the gland or anatomical localization. If the stones are large enough, they may be apparent on examination and may be palpable along the anatomic course of the affected salivary duct or gland.

Salivary stones’ size and weight vary. Sialoliths’ diameter ranges between 2.1 and 10 mm, and only 7.6% exceeds 15 mm in diameter.  Submandibular stones are usually larger than parotid ones. Sialoliths weigh 300 mg on average, ranging between 1 mg to 5 gr. 

If a stone is detected during a physical examination, the doctor may request imaging such as computer tomography and ultrasounds. Such is required to rule out related conditions as tumors, gland infection, Sjögren’s syndrome, malnutrition, radiation exposure, and reaction to iodine. While conventional radiography can be useful in the initial workup, CT scans or ultrasounds can accurately diagnose and provide the exact location of the stone.

Sialography is traditionally regarded as the gold standard for diagnosing sialolithiasis as it allows excellent visualization of the salivary ducts and underlying ductal pathology. In this technique, contrast is injected via a small needle, enabling radiographic visualization, acting as a sialagogue, and allowing passage of smaller stones. Disadvantages include radiation exposure and risk of contrast reaction. 

Treatment

Options to manage and treat sialolithiasis should begin with conservative measures, such as massages, non-steroidal anti-inflammatory drugs, and sialogogues. In case of cervical adenopathy, purulent discharge from the salivary ducts, or erythema, antibiotic therapy should be indicated.

Further treatment is dictated based on the sialolith's size, number, and location if conservative management is unsuccessful.

Sialendoscopy is the gold standard treatment for salivary stones. It is a minimally invasive procedure that uses a tiny endoscope to diagnose and treat salivary stones. The surgeon makes a small incision inside the mouth and inserts the endoscope to capture and remove the stone. Initially, stones measuring less than 5mm located within the distal duct should initially undergo management with endoscopy. Larger than 5mm should be treated with transoral duct slitting. The same treatment for the affected proximal or hilar duct.

Sialendoscopy allows for direct visualization of salivary stones and the salivary ducts, thus providing excellent sensitivity and specificity. In addition to aiding in the diagnosis of sialolithiasis, clinicians increasingly use sialoendoscopy for therapy and stone removal, given the advancements in endoscopic technology.  If this is unsuccessful or the stone becomes impacted, the next step is the transoral surgical approach. Surgical excision of the submandibular gland should be a last resort.

External shockwave lithotripsy (ESWL) is considered an option for non palpable (smaller) stones, or the ones visualized under endoscopy. It is generally unsuccessful for stones larger than 7 to 10 mm. Salivary stones within the parotid duct that measure less than 7 mm and are mobile require endoscopic removal. If endoscopic management is unsuccessful or the stones have become impacted, external shockwave lithotripsy is considered the most appropriate second-line therapy with subsequent endoscopic removal of fragmented stones. Treatment of salivary stones that do not respond to external shockwave lithotripsy is with a combined transcutaneous and endoscopic approach (assuming the stone is visible under endoscopy). Surgical excision of the parotid gland should be a last resort. 

Management ¹⁵

1. Conservative management: 

• Antibiotics / analgesics / mouthwashes / sialogogues / massaging the gland
• Antibiotic options cover staph aureus: Augmentin, clindamycin

2. Failing conservative management:

• Decision to intervene surgically is dependent on the requests of an informed patient and the clinicians successful correlation of symptoms with the pathologic process of sialectasis.
  • Facial pain in the absence of classic swelling associated with meals may be caused by processes other than salivary disorders.
• Consideration:
  • Gland removal as a a definitive invasive but usually (not always) successful approach with an emphasis on alternatives
    • Parotidectomy / Sjogren's Syndrome ( Sjögrens ) with Sialolithiasis Treated with Bilateral Parotidectomy.
    • Submandibular Gland Resection.
  • Sialendoscopy with laser fragmentation and basket removal:
    • Small stones (< 3 mm) reported 97% success rate with wire basket removal w/o fragmentation.
    • Larger stones (> 3 mm) reported 35% success with wire basket removal w/o fragmentation; increases to 72% with fragmentation; unusual to approach larger stones without attempted laser fragmentation
    • Extracorporeal Lithotripsy
      • Available in Germany and other sites in Europe but not in the United States- external lithotripsy may permit spontaneous extrusion of fragmented parotid stones in 40% of cases
      • Often done along with sialendoscopy to assist in removal of stone fragments.
  • Pneumatic Lithotripsy
  • Salivary Stone Removal with Ductoplasty from Submandibular Gland

Prognosis

Sialolithiasis has an excellent prognosis, and the majority of patients can be managed conservatively with sialagogues and NSAIDs. Even if the minimally invasive procedures discussed above have excellent success rates with minimal morbidity compared to traditional surgical techniques, additional research is required to establish the success of external or internal shockwave lithotripsy. Sialoadenectomy for the treatment of sialolithiasis is rarely necessary with modern treatment techniques.

Regulatory Status

This section is to be used for informational purposes only. FDA approval alone is not a basis for coverage.

The FDA has approved several lithotriptor devices. Refer to the following website for information and approved indications [use product code FFK or GEX (for laser-powered devices)]:

https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance/guidance-documents-medical-devices-and-radiation-emitting-products (current as of 05/27/22);

https://www.fda.gov/medical-devices/guidance-documents-medical-devices-and-radiation-emitting-products/guidance-content-premarket-notifications-intracorporeal-lithotripters-guidance-industry.

There is no FDA approval specified for extracorporeal lithotripsy.

Rationale

This evidence review was created in January 2023 with a search of the PubMed database. The most recent literature update was performed through September 30, 2024.

Evidence reviews assess the clinical evidence to determine whether the use of a technology improves the net health outcome. Broadly defined, health outcomes are length of life, quality of life, and ability to function including benefits and harms. Every clinical condition has specific outcomes that are important to patients and to managing the course of that condition. Validated outcome measures are necessary to ascertain whether a condition improves or worsens; and whether the magnitude of that change is clinically significant. The net health outcome is a balance of benefits and harms.

To assess whether the evidence is sufficient to draw conclusions about the net health outcome of a technology, 2 domains are examined: the relevance and the quality and credibility. To be relevant, studies must represent one or more intended clinical use of the technology in the intended population and compare an effective and appropriate alternative at a comparable intensity. For some conditions, the alternative will be supportive care or surveillance. The quality and credibility of the evidence depend on study design and conduct, minimizing bias and confounding that can generate incorrect findings. The randomized controlled trial is preferred to assess efficacy; however, in some circumstances, nonrandomized studies may be adequate. Randomized controlled trials are rarely large enough or long enough to capture less common adverse events and long-term effects. Other types of studies can be used for these purposes and to assess generalizability to broader clinical populations and settings of clinical practice.

Promotion of greater diversity and inclusion in clinical research of historically marginalized groups (e.g., People of Color [African-American, Asian, Black, Latino and Native American]; LGBTQIA (Lesbian, Gay, Bisexual, Transgender, Queer, Intersex, Asexual); Women; and People with Disabilities [Physical and Invisible]) allows policy populations to be more reflective of and findings more applicable to our diverse members. While we also strive to use inclusive language related to these groups in our policies, use of gender-specific nouns (e.g., women, men, sisters, etc.) will continue when reflective of language used in publications describing study populations.

Population Reference No. 1

Extracorporeal shock wave lithotripsy for management of sialolithiasis

Extracorporeal lithotripsy – For patients in whom a simple transoral surgical approach is not possible (typically stones in the proximal ducts or in the salivary glands themselves) or fails, extracorporeal lithotripsy appears to be effective for stones that are intraductal and less than 7 mm. However, extracorporeal lithotripsy for salivary stones is not approved by the US Food and Drug Administration (FDA).

Laser lithotripsy – Laser lithotripsy (available in some locations in the United States) is an alternative to extracorporeal lithotripsy and can be performed via endoscopy. Laser lithotripsy allows fragmentation of the stone prior to endoscopic removal.

Conservative management is the mainstay of treatment in primary care; patients should be instructed to keep well hydrated, apply moist heat to the involved area, massage the gland, "milk" the duct, and suck on the tart, hard candies to promote salivary flow. Pain should be managed with nonsteroidal anti-inflammatory drugs (NSAIDs) or occasionally opioid analgesics. Anticholinergic medications should be discontinued when possible. Patients with severe or persistent symptoms should be referred for specialist management.

Treatment Algorithms

Koch et.al (2021) reviewed and updated the algotrithm with the new developments, devices, materials and techniques, revealing significant changes in therapeutic strategies for the treatment of major salivary glands. Mainly, ISWL or Intraductal shock-wave lithotripsy has been improved and has replaced ESWL and TDS (transoral duct surgery), leading to a reduce use of them and the combined transcutaneous - sialendoscopic approach. See Parotid Gland Sialolithiasis Update.  

The Updated Algorithm for Submandibular Glands Stones 

1. Conservative Measures are always the first option. 

2.  Stones at the Papilla and in the Distal and Middle Duct:

• ISWL may be indicated in patients with unfavorable anatomic conditions, or in those who decline transoral duct surgery (TDS) in order to avoid general anesthesia. If ISWL is performed, papillotomy or a retropapillary duct incision may be necessary. 
• ESWL is not indicated for stones in this location. 

3. Stones in the Proximal to Hilar Duct System

• ISWL is indicated for small mobile stones (≤3–5 mm) due to the curved and very narrow duct system.
• ISWL followed by fragment extraction is indicated for immobile, impacted larger stones (<10 mm). 
• ISWL may be indicated in difficult cases when the patient has unfavorable anatomic conditions, in order to avoid general anesthesia.

4. Posthilar to Intraparenchymal Stones

• The indication for ISWL is heavily dependent on the anatomical situation, which determines the visibility and accessibility of the stones.
• ESWL is indicated if stones cannot be visualized endoscopically, are not palpable, and are located too far inside the duct system (>6.5–7.0 cm).
• ESWL is performed as a single treatment modality for stones >10 mm in size.

Updated Treatment Algorithm for Parotid Gland Stones

1. Conservative Measures are always the first option.

2. Stones in the Papilla and Distal Excretory Duct

• For stones that are of a hard consistency and/or are greater than 7 mm, ISWL is indicated.
• ESWL is indicated only in selected cases, i.e.  when there is unfavorable duct anatomy and/or a difficult stone location. 
• ESWL is indicated if distal stones are present in multiple sialolithiasis.

3. Stones in the Middle or Proximal Duct and Hilar Region

• Small, mobile stones (≤3–5 mm) are primarily an indication for intSE or ISWL. 

4. Hilar to Intraparenchymal Stones

• Up to 20% of all stones, these are more commonly impacted. 
• ISWL may be applied in favorable anatomic situations or if multiple sialolithiasis are present. 
• ESWL is a valuable and sometimes the only treatment modality if gland preservation is intended.

Population Reference No. 1 Policy Statement 

Updates of the treatment algorithm and review of recent literature reveals an improved Intraductal Shock Wave Lithotripsy in favor of the Extracorporeal Shockwave Lithotripsy, relegating the use of ESWL to selected cases such as indicated for <7mm stones, unfavorable locations or anatomy. The success rate of ISWL is that of 81-100% (5-7mm stones) wether with the utilization of ESWL is 26-81%(it drops with stone diameter). It also prevents the need for more invasive surgical management and gland loss. Also, sialendoscopy often performed following ESWL for complete stone fragment removal is Not FDA approved in United States¹⁸. Following a ESWL procedure, stones often cannot be completely cleared by salivary flow and residual fragments can cause recurrences. Conservative measures continue to be the first line of treatment, opting for sialoendoscopy combined with ISWL, and lastly ESWL for the more extreme or peculiar cases.

Laser lithotripsy – Laser lithotripsy (available in some locations in the United States) is an alternative to extracorporeal lithotripsy and can be performed via endoscopy. Laser lithotripsy allows fragmentation of the stone prior to endoscopic removal.

There is sufficient evidence to support the use of Intraductal Shockwave Lithotripsy (ISWL) for managing salivary stones.

Extracorporeal lithotripsy – For patients in whom a simple transoral surgical approach is not possible (typically stones in the proximal ducts or in the salivary glands themselves) or fails, extracorporeal lithotripsy appears to be effective for stones that are intraductal and less than 7 mm [29]. However, extracorporeal lithotripsy for salivary stones is not approved by the US Food and Drug Administration (FDA).

There is insufficient evidence to support the use of Extra-Corporeal Shockwave Lithotripsy (ESWL) for managing salivary stones.

Supplemental Information

The purpose of the following information is to provide reference material. Inclusion does not imply endorsement or alignment with the evidence review conclusions.

Practice Guidelines and Position Statements

Guidelines or position statements will be considered for inclusion in ‘Supplemental Information’ if they were issued by, or jointly by, a US professional society, an international society with US representation, or the National Institute for Health and Care Excellence (NICE). Priority will be given to guidelines that are informed by a systematic review, including the strength of evidence ratings, and include a description of the management of conflict of interest.

Medicare National Coverage

Medicare does not have a National Coverage Determination (NCD) for lithotripsy used in the treatment of salivary stones. Local Coverage Determinations (LCDs) do not exist at this time (Accessed September 30, 2024).

In the absence of a national coverage determination, coverage decisions are left to the discretion of local Medicare carriers.

References​​

1. Berry, R. L. (1995). SIALADENITIS AND SIALOLITHIASIS: Diagnosis and Management. Oral and Maxillofacial Surgery Clinics of North America, 479-503. doi:https://doi.org/10.1016/S1042-3699(20)30841-4

2. Capaccio P, Canzi P, Gaffuri M, et al. Modern management of pediatric obstructive salivary disorders: long-term clinical experience. Acta Otorhinolaryngol Ital. 2017 Apr; 37(2):160-167.

3. Capaccio P, Torretta S, Pignataro L, Koch M. Salivary lithotripsy in the era of sialendoscopy. Acta Otorhinolaryngol Ital. 2017 Apr;37(2):113-121. doi: 10.14639/0392-100X-1600. PMID: 28516973; PMCID: PMC5463518.

4. Chiesa-Estomba CM, Saga-Gutierrez C, Calvo-Henriquez C, et al. Laser-assisted lithotripsy with sialendoscopy: Systematic review of YO-IFOS Head and Neck Study Group. Ear Nose Throat J. 2021 Feb;100(1_suppl):42S-50S.

5. Desmots F, Chossegros C, Salles F, et al. Lithotripsy for salivary stones with prospective US assessment on our first 25 consecutive patients. J Craniomaxillofac Surg 2014 Jul;42(5):577-82.

6. Escudier MP, Brown JE, Putcha V, et al. Factors influencing the outcome of extracorporeal shock wave lithotripsy in the management of salivary calculi. Laryngoscope. 2010 Aug;120(8):1545-9.

7. Fazio, S. B. (n.d.). Salivary Gland Stones. Retrieved from Uptodate.com: https://www.uptodate.com/contents/salivary-gland-stones?search=Lithotripsy%20for%20Salivary%20Stones&source=search_result&selectedTitle=1~115&usage_type=default&display_rank=1#H37

8.  Guenzel T, Hoch S, Heinze N, et al. Sialendoscopy plus laser lithotripsy in sialolithiasis of the submandibular gland in 64 patients: A simple and safe procedure. Auris Nasus Larynx. 2019 Oct;46(5):797-802.

9. Hammett JT, Walker C. Sialolithiasis. [Updated 2022 Sep 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK549845/

10. Hayes, Inc. Directory. Sialoendoscopy for Salivary Gland Stones. August 2014. Updated July 16, 2015. Archived October 26, 2017.

11. Koch M, Schapher M, Mantsopoulos K, et al. Multimodal treatment in difficult sialolithiasis: Role of extracorporeal shock-wave lithotripsy and intraductal pneumatic lithotripsy. Laryngoscope. 2017 Dec 15.

12. Koch, M., Mantsopoulos, K., Müller, S., Sievert, M., & Iro, H. (2021). Treatment of Sialolithiasis: What Has Changed? An Update of the Treatment Algorithms and a Review of the Literature. Journal of clinical medicine, 11(1), 231. https://doi.org/10.3390/jcm11010231

13. Nahlieli O, Shacham R, Zaguri A. Combined external lithotripsy and endoscopic techniques for advanced sialolithiasis cases. J Oral Maxillofac Surg. 2010 Feb;68(2):347-53.

14. Phillips J, Withrow K. Outcomes of holmium laser-assisted lithotripsy with sialendoscopy in treatment of sialolithiasis. Otolaryngol Head Neck Surg. 2014 Jun;150(6):962-7.

15. University of Iowa Health Care. (2024, February 22). Sialolithiasis - Salivary Stones - What Causes Them and How to Manage. Iowa Head and Neck Protocols; University of Iowa Health Care. https://medicine.uiowa.edu/iowaprotocols/sialolithiasis-salivary-stones-what-causes-them-and-how-manage

16. Zenk J, Koch M, Iro H. Extracorporeal and intracorporeal lithotripsy of salivary gland stones: basic investigations. Otolaryngol Clin North Am. 2009 Dec;42(6):1115-37, Table of Contents. doi: 10.1016/j.otc.2009.08.005. PMID: 19962011.

17. Zenk J, Koch M, Klintworth N, et al. Sialendoscopy in the diagnosis and treatment of sialolithiasis: a study on more than 1000 patients. Otolaryngol Head Neck Surg. 2012 Nov;147(5):858-63.

18. Badash, I., Raskin, J., Pei, M., Soldatova, L., & Rassekh, C. (2022). Contemporary Review of Submandibular Gland Sialolithiasis and Surgical Management Options. Cureus, 14(8), e28147. https://doi.org/10.7759/cureus.28147

19. UpToDate:   https://www.uptodate.com/contents/salivary-gland-stones?search=Lithotripsy%20for%20Salivary%20Stones&source=search_result&selectedTitle=1%7E113&usage_type=default&display_rank=1

Codes

Policy History