Extracorporeal Lithotripsy for Salivary Calculi: A Long-Term Clinical Experience

Long-term rare giant sialolithiasis for 30 years: A case report and review of literature

BACKGROUND

Sialolithiasis is one of the most common salivary gland disorders, most commonly affecting the submandibular gland. Submandibular sialolithiasis can be treated using non-invasive conservative measures and invasive treatments. Treatment selection was based on the ductal system anatomy and the size and location of the stones. This study aimed to review the updates on sialolithiasis treatment and compare the different management strategies of the variables.

CASE SUMMARY

This report presents a case of a long-term, rare, and giant sialolithiasis within the submandibular gland parenchyma for 30 years in an older adult. Our patient presented with painless right submandibular swelling. Computed tomography revealed a calcified mass measuring 35 mm × 20 mm within the right submandibular gland. In this case, the infection and fibrosis of the affected gland and size of the stone did not provide us with other alternatives except for the excision of the involved gland. Thus, right submandibular sialoadenectomy was performed via the transcervical approach. After the surgery, the patient recovered without any complaints, side effects, or complications.

CONCLUSION

Tailored management is important for preserving gland function, maintaining low risk, and reducing patient discomfort.

Long-term rare giant sialolithiasis for 30 years: A case report and review of literature

BACKGROUND

Sialolithiasis is one of the most common salivary gland disorders, most commonly affecting the submandibular gland. Submandibular sialolithiasis can be treated using non-invasive conservative measures and invasive treatments. Treatment selection was based on the ductal system anatomy and the size and location of the stones. This study aimed to review the updates on sialolithiasis treatment and compare the different management strategies of the variables.

CASE SUMMARY

This report presents a case of a long-term, rare, and giant sialolithiasis within the submandibular gland parenchyma for 30 years in an older adult. Our patient presented with painless right submandibular swelling. Computed tomography revealed a calcified mass measuring 35 mm × 20 mm within the right submandibular gland. In this case, the infection and fibrosis of the affected gland and size of the stone did not provide us with other alternatives except for the excision of the involved gland. Thus, right submandibular sialoadenectomy was performed via the transcervical approach. After the surgery, the patient recovered without any complaints, side effects, or complications.

CONCLUSION

Tailored management is important for preserving gland function, maintaining low risk, and reducing patient discomfort.

Contemporary Review of Submandibular Gland Sialolithiasis and Surgical Management Options

One of the most common disorders of the salivary glands is obstructive sialolithiasis. Salivary gland obstruction is important to address, as it can significantly impact patient quality of life and can progress to extensive cellulitis and abscess formation if left untreated. For small and accessible stones, conservative therapies often produce satisfactory outcomes. Operative management should be considered when stones are inaccessible or larger in size, and options include sialendoscopy, laser lithotripsy, extracorporeal shockwave lithotripsy, transoral surgery, and submandibular gland adenectomy. Robotic approaches are also becoming increasingly used for submandibular stone management. The purpose of this review is to summarize the modern-day management of submandibular gland obstructive sialolithiasis with an emphasis on operative treatment modalities. A total of 77 articles were reviewed from PubMed and Embase databases, specifically looking at the pathophysiology, clinical presentation, diagnosis, and management of submandibular sialolithiasis.

The changing landscape of pediatric salivary gland stones: A half-century systematic review

OBJECTIVE

To assess the evidence for pediatric sialolithiasis, including its demographic characteristics, diagnosis, and demonstrate the shift in its treatment paradigm.

DESIGN

A systematic review of sources from the Medline and Embase databases was conducted from inception to Dec 4, 2020. Two researchers independently extracted data and assessed quality.

PATIENTS

Patients under the age of 18 with sialolithiasis were included.

MAIN OUTCOME MEASURES

Study design, cohort size, age, sex, symptoms, stone characteristics, diagnostic modality and intervention were collected data points.

RESULTS

Forty-one studies with 243 patients were included in the review, of which 40 were case reports or series. Most stones were found in the submandibular gland (n = 210, 85.4%) and were single stones (n = 101, 71.1%). Average stone size was 7.7 mm. The most common diagnostic imaging modality used was ultrasound (n = 73, 47.4%), shifting from plain radiograph which was favoured in earlier years. Similarly, open gland excision was historically preferred, but since 2000, sialoendoscopy comprised 40.5% of all treatment modalities and continues to increase in prevalence, up to 52.1% by 2020. Extracorporeal shock wave lithotripsy was associated with the highest complication rate of 54.2%.

CONCLUSIONS

The pediatric sialolithiasis diagnostic and therapeutic landscape has changed with ultrasound replacing plain radiographs, and sialoendoscopy replacing submandibular gland excision. Further high-level quality evidence research is required to refine the indications, effectiveness, and safety of sialoendoscopy in pediatric sialolithiasis.

Treatment of Sialolithiasis: What Has Changed? An Update of the Treatment Algorithms and a Review of the Literature

Treatment for sialolithiasis has undergone significant changes since the 1990s. Following the development of new minimally invasive and gland-preserving treatment modalities, a 40-50% rate of gland resection was reduced to less than 5%. Extracorporeal shock-wave lithotripsy (ESWL), refinement and extension of methods of transoral duct surgery (TDS), and in particular diagnostic and interventional sialendoscopy (intSE) are substantial parts of the new treatment regimen. It has also become evident that combining the different treatment modalities further increases the effectiveness of therapy, as has been especially evident with the combined endoscopic-transcutaneous approach. In the wake of these remarkable developments, a treatment algorithm was published in 2009 including all the known relevant therapeutic tools. However, new developments have also taken place during the last 10 years. Intraductal shock-wave lithotripsy (ISWL) has led to remarkable improvements thanks to the introduction of new devices, instruments, materials, and techniques, after earlier applications had not been sufficiently effective. Techniques involving combined approaches have been refined and modified. TDS methods have been modified through the introduction of sialendoscopy-assisted TDS in submandibular stones and a retropapillary approach for distal parotid sialolithiasis. Recent trends have revealed a potential for significant changes in therapeutic strategies for both major salivary glands. For the submandibular gland, ISWL has replaced ESWL and TDS to some extent. For parotid stones, ISWL and modifications of TDS have led to reduced use of ESWL and the combined transcutaneous-sialendoscopic approach. To illustrate these changes, we are here providing an updated treatment algorithm, including tried and tested techniques as well as promising new treatment modalities. Prognostic factors (e.g., the size or location of the stones), which are well recognized as having a strong impact on the prognosis, are taken into account and supplemented by additional factors associated with the new applications (e.g., the visibility or accessibility of the stones relative to the anatomy of the duct system).

Combined sialendoscopic/mini-preauricular microscopic approach for large proximal parotid sialolithiasis

OBJECTIVE

To describe and evaluate a combined approach for sialendoscopic stone localization with microscopic mini-preauricular incision external stone extraction as a gland-sparing minimally invasive surgical management in cases of large proximal duct or intraparenchymal parotid gland sialolithiasis.

METHODS

A retrospective chart review of a single primary surgeon's patient series of 21 cases operated in a 5-year period in a tertiary care university and private practice hospitals.

RESULTS

Study included 16 males and five females, with age range 12-68 years (mean 40.9 ± 14.5). Nineteen out of the 21 patients had their stones completely removed (90.5%), with two not completing the procedure due to inability of intraoperative endoscopic stone visualization. In total 25 stones were extracted with six patients having two stones. Longest diameter of single (or first) stone was 5-16 mm (mean 9.1 ± 2.9) and second was 3-5 mm (mean, 3.9 ± 0.6). Endoscopic findings showed 14/25 stones in the proximal main parotid duct and 11/25 in one of its secondary parenchymal branches. Stents were used in 4/19 cases (21.1%). No major complications occurred. Minor complications included two postoperative conservatively managed seromas. All 19 cases had completely intact facial nerve function, good parotid salivary flow and acceptable esthetic result after median follow-up period of 26 months (range 6-62).

CONCLUSION

The combined sialendoscopic/microscopic mini-preauricular approach is a highly effective and safe gland-preserving method for large proximal parotid sialolithiasis management with a main limitation being inability to visualize the stone endoscopically.

A gland-sparing, intraoral sialolithotomy approach for hilar and intraparenchymal multiple stones in the submandibular gland

Multiple intraglandular sialolithiasis for stones deep in the glandular parenchyma may require submandibulectomies, especially if sialendoscopic facilities are unavailable. We describe a gland-sparing intraoral sialolithotomy approach for both hilar and intraparenchymal multiple sialoliths. Nine patients with obstructive sialadenitis resulting from multiple sialoliths in both the deep hilar region and the submandibular gland parenchyma were selected for this study. Ultrasonography and computer tomography (CT) scans were performed to determine the location, number and sizes of the calculi and the distance between hilar and intraparenchymal sialoliths. All sialoliths were removed via gland-sparing, intraoral sialolithotomy. In all, 27 stones were found in the 9 patients. The hilar and deeper sialoliths were 4.5–11 and 0.8–4.5 mm, respectively, in diameter. The largest distance between the hilar and intraparenchymal sialoliths was 28.3 mm. Sialoliths in the hilar region were excised through an intraoral incision before deeper intraparenchymal stones were eased out of the same incision site. Postoperative follow-up imaging verified complete sialolith removal. Therefore, submandibular gland multiple sialoliths in the hilum and parenchyma can be successfully removed via an intraoral sialolithotomy under general anesthesia, thereby preserving the gland and restoring its secretory function.

Extracorporeal lithotripsy of salivary gland stone: A 55 patients study

Sialolithiasis are the most frequent salivary gland disease, mainly affecting the submandibular gland. With the advent of minimally invasive techniques, total salivary gland removal should not be considered as the first-line treatment anymore. Extracorporeal Shock Wave Lithotripsy (ESWL) is an alternative to surgery preserving the gland. The objective of our retrospective study was to evaluate the efficiency of ESWL on pain and obstructive syndrome in patients suffering from sialolithiasis. The global result felt by the patients was also considered. All patients treated between October 2009 and July 2016 for sialolithiasis by ESWL in our department were included. They were divided into two groups according to the concerned gland: a parotid gland (PG) and a submandibular gland (SMG) group. Our retrospective telephone questionnaire consisted in 4 questions about their symptomatology before and after ESWL, including pain self-evaluation before and after treatment. They were finally asked to evaluate the global result of the ESWL treatment: excellent, good, mean, or poor. In total, 55 patients were included in this study, 38 patients in PG group and 17 patients in SMG group. We observed a decrease of pain and obstructive syndrom after ESWL procedure in both groups. Better results were found on the obstructive syndrome in the PG group. Very few side-effects were reported by patients. Given that it has very few side effects, ESWL can easily be considered as first line treatment for sialolithiasis to avoid heavier treatments such as surgery. It should be the first-line treatment for symptomatic parotid sialolithiases. The treatment of symptomatic submandibular sialolithiases depends on the topography of the lithiasis.

Salivary lithotripsy in the era of sialendoscopy

The traditional management of obstructive salivary disorders has been replaced by minimally-invasive gland-preserving techniques including shock-wave lithotripsy, sialendoscopy, interventional radiology and endoscopically video-assisted trans-oral and cervical stone retrieval, of which sialendoscopy is considered to be the method of first choice. Primary endoscopically controlled stone extraction without prior fragmentation is only possible in 15-20% of cases; in more than 80%, fragmentation is necessary because of the size, impactation and location of the stone, or an alternative treatment such as transoral duct surgery or combined approaches are required. Moreover, about 10-20% of all stones cannot be adequately accessed by means of a sialendoscope or any alternative surgical method and, in such cases, extra-corporeal shock wave lithotripsy (ESWL) is the treatment of choice. However, in endoscopically accessible stones, ESWL is being gradually replaced by endoscopically assisted intra-corporeal techniques, including endoscopically guided laser and pneumatic intracorporeal lithotripsy. We describe the currently most widely used techniques for salivary lithotripsy, including ESWL, and endoscopically guided laser, electrohydraulic, electrokinetic and pneumatic intra-corporeal lithotripsy, and discuss their indications given the widespread use of advanced rehabilitative sialendoscopy and combined therapeutic approaches.

Transoral submandibulotomy for deep hilar submandibular gland sialolithiasis

OBJECTIVES/HYPOTHESIS

To assess the long-term results after transoral submandibulotomy for stones located in the deep hilar and intraparenchymal submandibular region.

STUDY DESIGN

Retrospective cohort analysis.

METHODS

Retrospective evaluation including all patients treated with transoral submandibulotomy for sialolithiasis at a tertiary referral center.

RESULTS

Complete stone removal at the first transoral surgical treatment was achieved in 185 of 234 patients (79.1%). One hundred seventy-five of the 234 patients were followed up for a mean of 31.2 ( ± 20.5) months. During the follow-up period, 140 of the 175 patients (80.0%) became symptom free after one operation. In patients with residual symptoms, no further treatment was needed in 12 patients (6.9%) due to the mildness of the symptoms; 23 patients (13.1%) received further therapy, which was successful in 15 cases. Submandibulectomy only had to be performed in 3.4% of the patients with follow-up (6/175). In a questionnaire survey, 91.4% of the patients stated that they would be prepared to have the same operation again.

CONCLUSIONS

These findings show that transoral removal of submandibular sialoliths located in the deep hilum or adjacent intraglandular parenchyma is an effective treatment that can be assisted by additional measures. The techniques described show high success rates, good long-term results, low complication rates, and they avoided the need for submandibulectomy in >95% of cases.

LEVEL OF EVIDENCE

4. Laryngoscope, 127:2038-2044, 2017.

Cost-effectiveness of transfacial gland-preserving removal of parotid sialoliths

OBJECTIVE

Examine outcomes of transfacial gland-preserving removal of difficult parotid stones and compare the cost and operative time to traditional parotidectomy.

STUDY DESIGN

Cost-effectiveness analysis and retrospective chart review.

METHODS

Patients who underwent transfacial removal of symptomatic parotid sialoliths at a tertiary medical center from June 2010 to July 2015 were evaluated. Outcomes included operative technique, stone size, stone location, complications, and symptom relief. In addition, patients who underwent traditional parotidectomy for chronic sialadenitis were identified. The charges and times for both procedures were reviewed and compared.

RESULTS

Forty-four patients underwent transfacial resection for symptomatic parotid sialolithiasis. Stones were most often located in the main duct and hilum (53.3%), with fewer intraglandular stones (46.7%). No facial nerve weakness was observed. Of those with follow-up, 33 (87%) patients reported at least partial resolution of symptoms. Overall transfacial technique charges were significantly less expensive (U.S.$) than parotidectomy (mean difference -8,064.09; 95% confidence interval [CI] -13,472.78 to -2,655.40; P = 0.033). Anesthesia charges (mean difference -2,997.85; 95% CI, -5,748.81 to -246.89; P = 0.035) and operating room charges (mean difference -4,793.91; 95% CI, -8,958.09 to -629.72; P = 0.028) were also less expensive for the transfacial technique. Finally, mean procedure time for transfacial removal of parotid stones was shorter than for parotidectomy (120.2 ± 49.9 vs. 178.4 ± 41.3 minutes, respectively; P = 0.002).

CONCLUSION

Transfacial gland-preserving removal of difficult parotid stones is a well tolerated and effective alternative to parotidectomy. Moreover, it is faster and less expensive than parotidectomy, maximizing both surgeon time and hospital resources.

LEVEL OF EVIDENCE

4. Laryngoscope, 127:1080-1086, 2017.

Structure and growth of sialoliths: computed microtomography and electron microscopy investigation of 30 specimens

Theories have been put forward on the etiology of sialoliths; however, a comprehensive understanding of their growth mechanisms is lacking. In an attempt to fill this gap, the current study has evaluated the internal architecture and growth patterns of a set of 30 independent specimens of sialoliths characterized at different scales by computed microtomography and electron microscopy. Tomography reconstructions showed cores in most of the sialoliths. The cores were surrounded by concentric or irregular patterns with variable degrees of mineralization. Regardless of the patterns, at finer scales the sialoliths consisted of banded and globular structures. The distribution of precipitates in the banded structures is compatible with a Liesegang-Ostwald phenomenon. On the other hand, the globular structures appear to arise from surface tension effects and to develop self-similar features as a result of a viscous fingering process. Electron diffraction patterns demonstrated that Ca- and P-based electrolytes crystallize in a structure close to that of hydroxyapatite. The organic matter contained sulfur with apparent origin from sulfated components of secretory material. These results cast new light on the mechanisms involved in the formation of sialoliths.

Algorithm changes in treatment of submandibular gland sialolithiasis

Our research was conducted to determine the algorithm changes during the treatment of submandibular sialolithiasis. Two time periods were compared between 2004-2008 and 2009-2012. The turning point was December 2008, when sialendoscopy procedure was introduced. In the first period, 48 patients were treated: 31 outpatient duct incisions with stone evacuation and 17 surgical excision of submandibular gland. In the second period, 207 sialendoscopy procedures were performed on 197 patients. Out of this particular group, 158 patients were diagnosed with pathological obstruction of salivary glands and 64 of them were confirmed to have sialolithiasis of submandibular gland. Deposits of calcifications in 40 individuals (62.5 %) affected by sialolithiasis were removed endoscopically; however, in 21 patients, due to the increased circumference of the stone, the intimate association of deposits within the wall of the duct along with its presence inside the deep portions of the gland, double approach (incision of the floor of the mouth in hilar area and sialendoscopy) was performed. Three individuals had their salivary glands totally removed due to the presence of calcified deposits within the glandular parenchyma. Our results allow us to affirm that sialendoscopy is the current treatment of choice for submandibular glands affected by sialoliths. Indication for a complete removal of the gland is becoming uncommon as a first line treatment although still indispensable in chosen cases.

Ho:Yag Laser for Sialolithiasis of Wharton’s Duct

Objective

To assess the feasibility of intracorporeal lithotripsy with holmium YAG laser under sialoendoscopic guidance for sialolithiasis of Wharton’s duct.

Study Design

Case series with planned data collection.

Setting

Tertiary referral university hospital.

Methods

This study was conducted on 16 patients with sialolithiasis of Wharton’s duct. Diagnosis was confirmed at ultrasound examination. Patients with stones ranging from 5 to 8 mm in diameter were enrolled in the study. The selected patients underwent intracorporeal lithotripsy with holmium Yag laser under endoscopic control. Debris was removed using sialoendoscopic forceps or a wire basket during the same procedure. After a 3-month follow-up, radiological tests were rerun.

Results

Stone fragmentation was possible in all cases. All patients experienced a regular postoperative course. Postoperative ultrasound examinations revealed residual stones in 3 patients, 1 of whom was asymptomatic. Three patients complained of residual symptoms after 3 months of follow-up. These patients were treated successfully during a second sialoendoscopic procedure.

Conclusions

In our experience, endoscopic laser lithotripsy was proved to be a feasible technique for Wharton’s duct lithiasis in clinical practice.

Sialoendoscopy and combined approach for the management of salivary gland stones

The introduction of minimally invasive surgical procedures has significantly reduced the rate of major salivary gland removal due to sialolithiasis. The aim of this study is to assess the effectiveness of sialoendoscopy, rate of salivary fistula or natural ostium stenosis in parotid sialolithiasis treatment. The endpoint was to analyse the efficiency of a combined transcutaneous and endoscopic approach in the removal of refractory and impacted stones in most difficult cases.

STUDY DESIGN

prospective study, tertiary university centre, between XII 2008 and XI 2011, 185 sialendoscopies (SE) were performed in 162 patients. Within the group of 29 patients with parotid sialolithiasis endoscopy was the definite treatment in 15 cases (53 %), in 9 cases lithotripsy (ESWL) was necessary and in 5 patients who failed SE and lithotripsy, a combined approach was performed. This approach comprised both SE and open surgery. We observed no salivary fistula formation after the incision of the duct. Stenosis of the natural ostium thanks to the insertion of stent was observed only in one case. Sialoendoscopy is the method of choice with a high rate of success and gland preservation in small and medium stones. The combined transcutaneous and endoscopic approach is indicated for large stones, for complications after and contraindications in using minimally invasive procedures. Short and medium term follow up shows that surgery can be performed with a high rate of success.

Extracorporeal lithotripsy techniques for salivary stones

Over the past 20 years, development of minimally invasive therapies has led to the use of extracorporeal shock wave lithotripsy (ESWL) to treat salivary stones. The two main energy sources are piezoelectric and electromagnetic extracorporeal lithotripsy. Both have the aim of fragmenting the stones. ESWL is considered the treatment of choice for all parotid calculi and submandibular perihilar or intraparenchymal stones of less than 7 mm. Continuous ultrasonographic monitoring during the procedure reduces the number of untoward effects. The main limitations are the need for multiple sessions and residual stone fragments inside the duct system.

Sialoendoscopic secondary intervention after failure of open sialolithectomy

PURPOSE

Traditionally, sialoadenectomy was always indicated when open sialolithectomy failed. The aim of the present study was to investigate the role of sialoendoscopy as the secondary intervention after failure of open sialolithectomy.

PATIENTS AND METHODS

A consecutive series of 15 patients with obstructive salivary gland disease with failure of open sialolithectomy were prospectively recruited for our study. All these patients underwent sialoendoscopy under local anesthesia. The reasons for the failure of open sialolithectomy were analyzed, and secondary interventions were performed using sialoendoscopy.

RESULTS

Failure of open sialolithectomy resulted from 4 main causes. Small stones could not be found after the duct was incised (n = 3); the stones were pushed posteriorly during open surgery (n = 4); the stones located in the anterior part of the duct were removed, but the hilar stones were left untouched (n = 5); and radiolucent stones were missed (n = 3). All the patients were treated successfully by sialoendoscopy. No symptoms or signs of recurrence developed during a median follow-up period of 16 months.

CONCLUSIONS

Sialoendoscopy can be recommended as an effective secondary intervention after failure of open sialolithectomy.

Combined Endoscopic and Transcutaneous Approach for Parotid Gland Sialolithiasis: Indications, Technique, and Results

OBJECTIVE: Despite all the advances of minimally invasive surgery, refractory stones remain in 10 to 20 percent of all cases of parotid gland sialolithiasis, and persistence of the symptoms makes removal of the gland inevitable. In some of these cases, however, it may be possible to conserve the gland using a combination of endoscopic and transcutaneous procedures.

STUDY DESIGN: Case series with chart review.

SETTING: Tertiary referral center.

SUBJECTS AND METHODS: Nine patients treated with a combined endoscopic transcutaneous operation were evaluated. During this procedure, the stone is removed through a skin incision under endoscopic guidance. Indications were sialolithiasis refractory to treatment (n = 5), sialolithiasis with complications (n = 2), contraindications to primary minimally invasive surgery (n = 1), and primary treatment (n = 1). In seven cases, the stones were extracted. Simultaneous resection of a sialocele was carried out in one case, and simultaneous resection of a saliva-cutaneous fistula was carried out in another. A stent was inserted in 66.7 percent of the cases.

RESULTS: Treatment was successful in 88.9 percent of the patients. All of these patients were free of stones and symptoms, and glandular function was maintained both clinically and on ultrasound assessment. Complete parotidectomy had to be carried out in one case because it was not possible to reconstruct the duct system.

CONCLUSION: The combined operation offers a further option for gland-conserving treatment in cases with obstructive salivary gland disease, especially sialolithiasis. At present, it is indicated for cases that are resistant to treatment after sialendoscopy or extracorporeal shock wave lithotripsy. The gland resection rate can thus be further reduced.

Submandibular Gland Excision: 15 Years of Experience

PURPOSE

The surgical management of submandibular gland diseases has always been a challenge because it carries a considerable risk of nerve injury. The aim of this study was to review a single institution's experience of a nonselected case series of submandibular gland excision over 15 years.

MATERIALS AND METHODS

We retrospectively analyzed 258 unselected submandibular excisions of a tertiary university center for the histopathologic diagnosis and postoperative morbidity; 119 patients (46%) with sialolithiasis, 88 patients (34%) with sialadenitis, and 51 patients (20%) with submandibular tumors were operated.

RESULTS

We found a high rate of malignant tumors (42%) in the group of submandibular gland tumors. A low rate of transient palsies of the mandibular branch of the facial nerve (9%) and lingual nerve (2%) was observed. One patient developed a permanent paresis of the mandibular branch (<1%).

CONCLUSION

Our large series has shown that standardized submandibular sialadenectomy is a safe operation with a low rate of complications. Malignant disease is frequent in tumors of the submandibular gland.

Interventional Sialography and Minimally Invasive Techniques in Benign Salivary Gland Obstruction

Salivary gland obstruction is the commonest complaint affecting this organ and is usually due to the development of salivary calculi, ductal strictures, or both. Imaging has a role in the diagnosis of the cause, extent, and effects of obstruction. In recent years, the role of radiology has evolved; techniques, such as salivary stone lithotripsy, and salivary stone extraction and balloon ductoplasty are carried out under imaging guidance. This article reviews the current status of minimally invasive salivary interventions.

An Er:YAG laser endoscopic fiber delivery system for lithotripsy of salivary stones

BACKGROUND AND OBJECTIVES

Endoscopic applications of Erbium:YAG lasers are still very limited due to lack of appropriate fiber delivery capabilities. Recent reports on potential advantages of this laser for lithotripsy of ureteral stones prompted us to develop an Er:YAG fiber delivery system for endoscopic lithotripsy of salivary stones. We report on the development of this system and its clinical use on 17 patients.

STUDY DESIGN/MATERIALS AND METHODS

Ho:YAG and Er:YAG laser fragmentation performances were initially compared. Optimal laser parameters for lithotripsy of salivary stones were then established ex vivo using a commercial dental Er:YAG laser (Lumenis Opusdent 20). Metal hollow waveguides optimized for Er:YAG laser transmission were end sealed with a polished sapphire rod of 0.63 mm diameter and designed to adapt to the Opusdent laser and to a Storz sialoendoscope. The system was tested ex vivo for durability and clinical compatibility at input energies up to 700 mJ, 10-20 Hz. Following Helsinki approval the system was clinically tested on 17 patients with sialolithiasis.

RESULTS

Lithotripsy threshold was around 80 mJ/pulse (26 J/cm2) while efficient fragmentation, with microscopic fragments, was observed at an output energy range of 150-300 mJ/pulse. At 10 Hz, fragmentation rates of about 1.8 mm3/second were achieved enabling lithotripsy of a 6 mm stone in about 2 minutes. Front surface damage to the sapphire rod occurred but did not contribute to significant loss in fragmentation efficiency. Of the 21 stones treated clinically, 5 were fully fragmented, 7 were prepared for extraction by mini forceps, and 9 were released from surrounding soft tissues for subsequent removal. Fifteen of the 18 treated glands returned to normal function without any symptoms.

CONCLUSIONS

The Er:YAG endoscopic delivery system described is a clinically viable and cost-effective device for a range of hard and soft tissue wet field applications accessible through rigid or semi-rigid endoscopes. Further improvements in the waveguide may allow access also through fully flexible endoscopes.