Standardization of Basket Use in Sialendoscopy: A Ten-Year Retrospective Study

Summary

We present the standardization of the basket use in sialendoscopy for obstructive sialolithiasis in a consecutive ten-year series of patients with obstructive salivary gland, describing localization, stone evaluation, size estimation, choosing basket type, and choosing approach technique (Frontal, Side-to-Side, Back-to-Forward) to achieve a high success rate in its removal.

Abstract

Sialolithiasis is a common cause of obstructive salivary gland disease, occurring in both submandibular and parotid glands. The treatment has evolved with the introduction of Sialendoscopy and micro-instruments (baskets, wires, and balloons), which allow intraductal manipulations, including stone removal and strictures, to be dilated. Nowadays, it is the main option for effectively treating these obstructive conditions, leading to improvements in overall quality of life. The objective of the present 10-year retrospective review is to standardize the basic steps involved in successfully removing intraductal sialolithiasis with a Basket instrument.

A consecutive ten-year series (January/2014 to June/2024) of patients with obstructive submandibular and parotid glands due to sialolithiasis who underwent sialendoscopy using a basket successfully removed were analyzed. The procedure was conducted following the standards; all interventions were video-recorded and performed by the same surgical team using a semi-rigid modular sialendoscope (1.3 mm/1.7 mm diameter) with working channel, salivary probes, dilatators, different baskets (0.4 mm diameter and 3, 4 and 6 wires) for stones and dilatations, using some steps previously reported.

In 10 years, we have performed 224 sialendoscopy due to salivary gland obstructive disease, 84.4% from sialolithiasis. The successful sialolith removal with the basket was performed using pure sialendoscopy (PS-study group) in 132 (69.8%) patients: 79.5% female patients, mean age 44.8 years; 68.9% in the submandibular gland, 65.9% single stones, with 0% major complications. The basic steps were a) how to localize; b) to evaluate (mobile/hard/single stone); c) to estimate sialolith size; d) to choose basket type; e) to choose approach technique (A: Frontal:9.1%, B: Side-to-Side: 35.6%, C: Back-to-Forward: 55.3%). All sialoliths were completely removed, and the patients recovered uneventfully. This article details the standardization of the use of basket in removing ductal stones during sialendoscopy, which is necessary to achieve a high success rate in its removal.

Introduction

The obstructive salivary gland disease is due to sialolithiasis in almost 60% of cases, the strictures, mucoid debris, and anatomic ductal abnormalities among the other causes¹. Nearly 80%-95% of sialolithiasis cases occur in the submandibular gland and 5%-20% in the parotid gland². This condition has also been proven by image studies, usually ultrasound, computed tomography, or eventually magnetic resonance^3,4,5.

Their treatment has evolved in the last 25 years since the introduction of sialendoscopy with very thin semi-flexible endoscopes and adequate miniaturized related instruments like forceps, baskets, wires, and balloons. These new instruments allowed intraductal manipulations, including stone removal, dilatation of strictures, and cleansing of mucus plugs during sialendoscopy². In some special cases, all these procedures can be used in combination with minimally invasive external approaches⁶.

Nowadays, sialendoscopy is the main option for effectively treating these obstructive conditions, leading to improvements in overall quality of life^7,8,9. Nevertheless, no article has clearly shown the standardized basic steps to follow in the sialolithiasis treatment through sialendoscopy using the basket instrument.

The basket instrument use during sialendoscopy is a well-established technique for the retrieval of salivary stones, and it must be done inside the duct, a clear advantage over the open surgical techniques once this last involves the mucosal and skin incisions, nerve manipulations, and sometimes salivary gland excision^10,11,12. In this point of view, the knowledge of how to properly use the basket in a patterned way will help the assistant surgeon to adequately and safely treat these salivary obstructive conditions, saving surgical time, saving the salivary gland, and avoiding potential complications^{2,13,14,15,16}.

The basket use procedure typically involves the following intuitive steps: Identification and access of the salivary duct through a sialendoscope, stone identification, introduction of the basket through the sialendoscope, opening of the basket, stone capture, and retrieval^15,17,18. These steps are usually done with a relatively good success rate in experienced hands but have potentially hardazous complications, like avulsion of the salivary duct, gland swelling, salivary fistulas, stuck basket inside the duct, salivary ducts perforations (false rout - "via falsa"), traumatic ranulas, and the lingual nerve paraesthesia^14,16.

There is also no detailed article describing the standardized intraductal use of the basket instrument during the sialendoscopy in a series of patients for a safe and high success rate, an apparently simple task that is still done in intuitive mode. Some studies have described random and non-standardized movements of the basket to engage the stone in the region of the hilum of Stensen's duct, but without mentioning the success rates for each maneuver or how it has been used in other parts of the main duct¹⁹. The rationale and correct application of standardized basket use for the removal of salivary stones will allow the adequate treatment of sialolithiasis with sialendoscopy while reducing operative time and related complications.

The present method proposed by the authors should be used whenever possible in any situation where intraductal salivary stones can be removed mainly via pure sialendoscopy or sometimes in association with a planned combined procedure.

In the protocol below, we used these important definitions of approach techniques.

Type A: Frontal - The tip of the basket is located against the anterior part of the sialolith, and the opening of the basket threads is made anterior to the sialolith. By instilling a sterile physiological 0.9% saline solution, the stone can move anteriorly into the basket, becoming trapped.

Type B: Side-to-Side -The tip of the basket is located next to the sialolith, and during the opening of the basket threads, the position is on the side of the sialolith and by instilling sterile physiological 0.9% saline solution, the stone can move laterally into the basket, becoming trapped.

Type C: Back-to-Forward -The tip of the basket is located posterior to the sialolith, and the opening of the basket wires is made posterior to it, bringing it anteriorly to the sialolith to trap it inside the basket

The main objective of this 10-year retrospective review is to standardize the basic steps involved in successfully removing intraductal sialolithiasis with the basket instrument, facilitating the handling of the instruments and the basket during sialendoscopy, making the procedure highly safe and successful.

Protocol

All procedures were conducted under institutionally approved protocols, in accordance with the Institution Human Research Ethical Guidelines, and approved by the Ethics Committee. Informed consent was obtained from the patients to film the surgery for educational purposes before starting the process.

NOTE: The materials suggested to be used are semi-rigid modular sialendoscope, as listed in the Table of Materials, with a diameter of 1.3 mm or 1.7 mm and with the working channel; salivary probes, conic dilatators, bougies, baskets for stones, dilatator balloons, silastic stents, and sterile physiological 0,9% saline solution.

1. Preoperative procedures

1. Once in a sterile field, check the sialendoscopes and support instruments by carefully inspecting them and verifying the integrity of the material. (Figure 1A,B).
2. Inspect and check the basket operation by testing the opening of the wires manually outside the duct system, following the instructions in the manufacturer's manual. (Figure 1C).
3. Inspect and check the operation of the inflated balloon by filling the balloon with sterile physiological 0.9% saline solution, according to the volume recommended by the manufacturer, which varies from 0.2-0.4 mL, always following the instructions in the instruction manual.
4. Inspect and verify the operation of the fiber optic cables connecting them to the video rack lighting system, initially maintaining a low light intensity, about 50% of the possible, and connecting the other end to the fiber optic plug of the sialendoscope (Figure 1D).
5. Inspect the video camera cable and connect the video camera of the video set, properly protected with sterile wrap, to the video connector of the sialendoscope.
6. Inspect and check the image on the video monitor screen for the presence of light and the quality and image formation while trying to read the wire packing label.
7. Adjust the camera zoom to focus the image by rotating the video image adjustment to eliminate the presence of "honeycombs" in the image seen on the monitor screen. Use the label on the wire packaging to ensure the letters are seen and have acquired better image quality.
8. Insert the optical fiber into the sialendoscope if using the "sheets" for sialendoscopy, adjusting it so that it is correctly adapted to the material. Follow the same steps above to calibrate the video set.
9. Locate the irrigation channel of the sialendoscope caudally, with the optical fiber located in the middle of the instrument and the working channel located cranially. Use the label on the wire packaging to correctly position the "north" of the sialendoscope on the image screen.
10. Connect the saline solution equipment containing full sterile physiological 0.9% saline solution to the irrigation channel, checking that no air bubbles have formed inside that will interfere with the formation of the video image in the ductal system.
11. Check and mark the correct side of the patient's neck or face to do the sialendoscopy with a washable surgical pen marker; do the same on the salivary gland on which the sialendoscopy is to be performed (Safe Surgery Protocol).
12. Perform all the operations under general anesthesia, with the use of salivating stimulators like neostigmine as the surgeon's choice: adult single dose of neostigmine 0.5-2.5 mg (0.05-0.07 mg/kg) to be administered simultaneously (in separate syringes) with atropine sulfate 0.6-1.2 mg (0.02 to 0.03 mg/kg) by slow intravenous (IV) injection over 1 min, with caution, in accordance with the anesthesiologist preferences and following the manufacturer data sheet.
13. Perform all the steps above before starting the anesthetic procedure in the operating room. Ensure all interventions are video-recorded and performed by the same surgical team for diagnostic and therapeutic procedures.

2. Sialendoscopy technique

1. Place the patient in the supine position under general anesthesia with the orotracheal tube located on the contralateral side of the gland for sialendoscopy.
2. Perform the routine mouth asepsis and antiseptic following the rules with proper oral 0.2% chlorhexidine mouthwash and covering the sterile surgical field, ensuring that the side on which sialendoscopy is to be performed is exposed.
3. Check the sialendoscope again as soon as the sterile field is ready on the patient, making the necessary adjustments: to the white balance, press the WB button on the camera or in the video device located in the video set; do the same to adjust the zoom and focus on the camera.
4. Check again for the spatial orientation of the optical instrument, which is necessary for safe intraductal navigation.
5. Put the open-mouth gag on the contralateral side, adequately exposing the papilla of the salivary gland to be submitted to sialendoscopy, either submandibular or parotid gland.
6. Dilatate progressively the salivary gland papilla with dilatators until it fits the adequate size of the sialendoscope to allow the insertion of the sialendoscope and proper visualization of the duct (Figure 2).
7. Introduce delicately the sialendoscope inside the main duct, and connect a 20 mL syringe filled with sterile 0.9% physiological saline solution or sterile isotonic water to the irrigation system connected to the sialendoscope irrigation system.
8. Slowly and carefully inject small portions, with low pressure, sufficient volume of the sterile 0.9% physiological saline solution to distend the duct that will be visualized on the video monitor screen.
9. Navigate gently into the duct once it is distended, allowing the sialendoscope to enter it effortlessly without major maneuvers and twists (Figure 3).
10. Inspect the main duct, secondary and tertiary ducts as possible, in detail with sialendoscope, cleaning from mucus plugs using the saline solution irrigation instilled by the syringe in small amounts as much as necessary to clean it, which should not usually exceed the total volume of 60 mL in the entire procedure, taking into account the loss (exit) of saline solution into the oral cavity around the sialendoscope in the salivary papilla.
11. Locate the stone(s) inside the duct after cleaning it, and be prepared to perform the salivary stone capture maneuvers.

3. Basic steps on standardization of basket use in sialendoscopy

1. Initial inspection:
   1. Exam with the sialendoscope all duct extensions during this initial phase, looking for stenosis presence and evaluate the stenosis along the main, secondary, and tertiary ducts.
   2. Note the appearance of the duct stenosis and its location, and estimate its size by comparing it to the main duct. (Figure 4). Also, observe the stone presence after the stenosis (if any) and how the saliva is affected by the last (milky or clear appearance) (Figure 5).
2. Localization of sialolithiasis
   1. Inspect the main duct, secondary, and tertiary ducts, looking directly for stones after the initial inspection, and make notations where the stone is located in the main duct, secondary, or tertiary ducts (Figure 6A, B).
3. Sialolithiasis estimation
   1. Size: Observe the sialolith carefully and make notes of the size of the stone(s) (i.e., all duct diameter or lesser than duct diameter) (Figure 7A, B).
   2. Number: Identify if the stone(s) are single or multiple, trying to establish a plan of treatment (single or multiple attempts) (Figure 8A, B).
   3. Mobility: Move the sialendoscope and flush the sterile 0.9% physiological saline solution carefully at the same time to observe and evaluate the mobility of the stones, recording their characteristics as fixed/little mobility or mobile stones (floating along the duct).
   4. Consistency: Identify and try to presume the stone's consistency by its physical appearance and/or touch it gently with the sialendoscope and try to feel it by the touch, as hard or soft.
4. Basket type selection: 3, 4, 6 wires: Choose the appropriate basket based on observations of steps 3.2 and 3.3 to achieve a higher chance of trapping the stone. Note that small stones will need more wires to facilitate the catch maneuver, and bigger and small mobility stones will require fewer wires (Figure 9A, B).
5. Approach technique
   1. Type A: Frontal:
      1. Choose the Type A-frontal approach after complete evaluation as described above by putting the tip of the basket against and very close to the anterior part of the sialolith (Figure 10A).
      2. Open the wires gently, carefully flush the saline solution, and try to trap the stones as they move the saline solution into the basket. (Figure 10B). This approach is ideal for mobile, smaller and occasionally soft stones, using the 4 to 6 wires basket.
   2. Type B: Side-to Side:
      1. Choose this type of approach for a relatively mobile, single stone that is smaller than the size of the duct. To do this, place the tip of the basket next to the stone, and by doing so, the wire will be located on the side of the sialolith. (Figure 11A).
      2. Carefully flush the sterile 0.9% physiological saline solution with the soft movement of the open basket to dislodge the stone and catch it with the basket. (Figure 11B).
   3. Type C: Back-to-Forward:
      1. Choose this type of approach in cases of all-duct size stones with hard consistency or single stones with little mobility.
      2. Put the tip of the basket posterior to the sialolith (Figure 12A), and make sure to open the wires posterior to it. After this, slightly bring the wires of the basket anteriorly, and at the same time, gently flush the sterile 0.9% physiological saline solution (Figure 12B).
      3. Finally, after the wires are around the stone, secure the stone, pulling the basket wires. (Figure 12-C).
6. Final inspection: Make the final duct inspection before finishing the procedure; it is when the main duct, secondary, and tertiary ducts are evaluated afresh, looking for residual stones and stenosis. Be prepared to solve any other problem again and repeat the above steps if necessary (Figure 13).
7. Remove the endoscopic system and evaluate the papilla or duct stent necessity, putting it in appropriate extension and orientation and fixing it to the mucosa with a non-absorbable suture.
8. Finish the endoscopic procedure, stop the video recording, and allow the patient to wake up safely. Evaluate the face and neck again looking for major swelling of the salivary gland to prevent airway distress. In this case, allow to recover more time than conventional in the recovery room properly monitored.

4. Pos-operative procedures

1. Keep the patient in-hospital for 1 day, as intense pain and swelling in the salivary gland area occurs in some patients. Treat with analgesics, antibiotics (usually cefazoline), and a soft diet.
2. Mobilize the patient as soon as possible following the procedure.
3. Discharge the patient on the following day if there are no complaints.

Results

In 10 years, we have performed 224 consecutive sialendoscopies due to salivary gland obstructive disease. Of these, 189 (84.4%) were caused by sialolithiasis. The successful sialolith removal with Pure sialendoscopy only (PS-study group) was done in 132 (69.8%) patients, all with uniglandular disease, utilizing the above-mentioned protocol.

In the PS study group (n = 132), there were 105 (79.5%) female patients, with a mean age of 44.8 years (ranging from 15 years to 84 years); the endoscopic ...

Discussion

Currently, in the general population, despite the heterogeneity of the studies, nearly 60-70% of obstructive salivary gland disease is caused by sialolithiasis. Nowadays, sialendoscopy is the main treatment option, removing stones and strictures and becoming the gold standard to treat these conditions as it restores the quality of life, keeping a functioning salivary gland intact^1,7,22.

However, in th...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Baskets for stones	Humanna medical, Brazil	https://www.humannamedical.com.br/post/kit-canula-para-exerese-de-calculo-salivar	3,4 and 6 wires
Bougies	Karl Storz, Tuttlingen, Germany	https://www.karlstorz.com/br/pt/search.htm?cat=1000246143	varying in 3 sizes
Conic dilatators	Karl Storz, Tuttlingen, Germany	https://www.karlstorz.com/br/pt/search.htm?cat=1000246143	unique
Dilatator balloons	Humanna medical, Brazil	https://www.humannamedical.com.br/post/kit-canula-para-exerese-de-calculo-salivar	0.4ml
Saline Solution 0.9%	Fresenius Kabi	https://www.fresenius-kabi.com/br	100ml
Salivary probes	Karl Storz, Tuttlingen, Germany	https://www.karlstorz.com/br/pt/search.htm?cat=1000246143	varying from number 0000 to 6
Sialendoscopes	Karl Storz, Tuttlingen, Germany	https://www.karlstorz.com/br/pt/search.htm?cat=1000246143	different semi-rigid modular Sialendoscope varying  diameter  1.1mm, 1.3 mm, 1.6mm, 1.7 mm
Silastic stents	Humanna medical, Brazil	https://www.humannamedical.com.br/post/kit-canula-para-exerese-de-calculo-salivar	varying in number: 4Fr, 6Fr, 8Fr
Video Set- Equipment carts and Monitor carts, cables	Karl Storz, Tuttlingen, Germany	https://www.karlstorz.com/br/pt/online-catalog.htm	consisting in Video Monitor, Light xenon 300, Video recorder camera