SQU Med J, December 2010, Vol. 10, Iss. 3, pp. 382-387, Epub. 14th Nov 10 
Submitted 5th Dec 09, Reformat Recd. 24th Apr 10
Revision ReQ. 5th July 10, Revision recd. 7th Aug 10
Accepted 8th Sept 10

Sialolithiasis, the formation of stones in the salivary gland, results in a mechanical obstruction of the salivary duct, causing 
recurrent glandular swellings during meals which 
are transitory, or complicated by bacterial infections 
accompanied by fever, purulent discharge at the 
papilla, and painful glandular swelling. Salivary 
stones occasionally form in a salivary gland or duct, 
usually by deposition of calcium salts around a nidus 
of organic material, and have a layered microscopic 
structure.   

In contrast to urolithiasis and cholelithiasis, the 
aetiology of sialolithiasis is unknown.1 and various 
hypotheses have been proposed.2,3 Salivary stones 
can be either solitary or multiple, particularly in the 
parotid gland. They vary in size and shape, being 
either round or irregular [Figure 1]. They can either 

float in the lumen, or become partially fixed due to 
an irregular shape, or even attach to the ductal wall. 
A less frequent diagnosis is intraductal stenosis, 
which might be localised [Figure 2], or diffuse on a 
portion of the main duct. Sialolithiasis is estimated 
to affect 1:10–20,0004 and the incidental ratio of 
submandibular/parotid is described as 90/10, but 
in the Geneva experience is a ratio of 60/40; this 
difference is possibly explained by the sensitivity of 
the new detection methods, and local recruitment.5,6

In the classical approach, distal stones close to 
the papilla are simply extracted,7 whereas glandular 
resection is indicated for deeply located stones. 
In submandibular glands, sialolithiasis surgery 
still represents 70–90% of all actual indications8 

for surgery, which may carry a risk of facial nerve 
injury.9 Parotidectomy is rarely performed for 

1Department of Surgery, Sultan Qaboos University Hospital, Muscat, Oman; 2Department of Otorhinolaryngology, Head & Neck 
Surgery, University Hospital, Geneva, Switzerland.  
*Corresponding Author email: ralabri@hotmail.com

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aBstract: Sialendoscopy is one of the innovations introduced in the last few years in the field of otolaryngology, 
head and neck surgery. Sialolithiasis and sialadenitis are two of the most frequently presenting disorders of the 
salivary glands. The diagnosis is most frequently confirmed by radiology and the treatment of sialolithiasis ranges 
from the use of surgery, intra-oral extraction or external lithotripsy, to the more frequent external excision of 
the gland. Sialendoscopy uses minimal invasive surgical techniques which allows for optical exploration of the 
salivary ductal system and extraction of the stones by a basket under endoscopic view. Sialendoscopy incorporates 
diagnostic with therapeutic procedures, as dictated by the clinical findings. This technique can be performed in 
most cases as an ambulatory, outpatient procedure under local anaesthesia.

Keywords: Sialolithiasis; Sialendoscopy; Salivary glands

New era of Endoscopic Approach 
for Sialolithiasis: Sialendoscopy

*Rashid Al-Abri1 and Francis Marchal2

TECHNICAL NOTE



Rashid Al-Abri and Francis Marchal

Technical Note | 383

inflammatory conditions in parotid glands, because 
it remains a tedious procedure and involves a higher 
incidence of postoperative paresis.10 

A possible reason for this high rate of 
submandibular resections might be the common 
belief that a gland suffering from long standing 
sialolithiasis is no longer functional. In a clinical-
histopathological study on 48 patients afflicted with 
sialolithiasis and treated with glandular resection, 
half of the patients had subnormal histology 
patterns, and there was no correlation between the 
number of infectious episodes and the alteration 
of the gland.11 Therefore, numerous infectious 
episodes or a long duration of symptoms cannot be 
used to predict the degree of glandular alteration, 
and thus a minimally invasive approach towards 
sialolithiasis appears justified.

Several new techniques have been developed 
since 1990 to fragment sialoliths such as 
extracorporeal lithotripsy.12 Success rates for 
extracorporeal lithotripsy vary from 40–75% 
for the submandibular and parotid glands,  
respectively. Performed on an outpatient basis, 
this technique is now widely practised, but often 
requires multiple sessions. The main problem 
remains the clearance of fragments, which can 
be incomplete and could become the cause of  
recurrent sialolithiasis. The classical investigation 
methods of salivary glands are radiography, 
including X-rays, ultrasound and computed 
tomography scans and sialography.13 Ultrasound 
remains an excellent primary diagnostic method  
for the detection of salivary stones; however,  

calculi with a size less than 3 mm can hardly be 
visualised.14 Another new non-invasive diagnostic 
option is nuclear magnetic resonance tomography, 
which provides scans of the salivary ducts by 
opacification of the natural salivary pathway  
without the need for administration of contrast 
medium and without exposing the patient to 
ionising irradiation.5 These procedures aim to 
visualise the ductal system for the diagnosis of 
obstructive pathologies, typically stones or other 
rarer diseases. 

Sialendoscopy is a new procedure, aiming 
to visualise the lumen of the salivary ducts and 
their pathologies. The first reported attempts to 
visualise the ducts were conducted in the early 
1990s.15,16 Major advances in optical technologies 
and the development of semirigid sialendoscopies 
are responsible for significant progress in salivary 
gland endoscopy.17 This procedure, by allowing the 
complete exploration of the salivary ductal system, 
is positioned to replace sialography and other 
radiological studies15  because of its higher specificity 
and cost-effectiveness. Patients with suspected 
sialolithiasis comprise the major population for 
whom sialendoscopy is indicated. This technique 
can be performed in most cases as an ambulatory, 
outpatient procedure18 with advantages of no 
scar, elimination of facial nerve paralysis of the  
marginal mandibular branch, and lower morbidity, 
especially for older patients with co-occurring 
disorders. 

They are two types of sialenoscopy,  
diagnostic and interventional. The diagnostic and 

Figure 1: Salivary stones can be unique or multiple and 
vary in size and shape, and be either round or irregular as 
demonstrated in this endoscopic view

Figure 2: Endoscopic view of a concentric stenosis in the 
second branch of Stensen’s duct as shown by sialendoscopy



New era of Endoscopic Approach  
for Sialolithiasis: Sialendoscopy

384 | SQU Medical Journal, December 2010, Volume 10, Issue 3

interventional sialendoscope (1.33 mm2 surface, 
1.3 mm diameter) [Figure 3] provides excellent 
vision and is recommended both for diagnostic 
and interventional procedures as it has a rinsing 
channel as well as a working channel. Recently 
new generations of all-in-one endoscopes became 
available to be used for the same purposes.

Diagnostic Sialendoscopy
The endoscopic technique described19,20 allows 
almost complete exploration of the ductal system 
(main duct, secondary and tertiary branches) [Figure 
4], mainly because of the small diameter of the 
scopes (0.9 and 1.3 mm). Diagnostic sialendocopy 
was used to classify ductal lesions into sialolithiasis, 
stenosis, sialodochitis, and polyps. Over the 
last 1,000 endoscopies performed, diagnostic 
sialendoscopy could be achieved in 98% of cases  
and reduced the need for radiological investigations. 
Rare limitations include convoluted sections that 
are impassable with a rigid endoscope.18,1 Mobility 
of the endoscope is also limited at the distal end of 
the gland. Diagnostic findings showed that mucous 
plugs are found in cases of sialolithiasis and also in 
cases of Sjögren syndrome and in several cases of 
chronic parotitis in children [Figure 5]. 

Interventional 
Sialendoscopy
Interventional sialendoscopy is used to  
treat disorders discovered during diagnostic 
sialendoscopy. The attitude is the same for the 
submandibular and parotid glands,1 although the 
diameter of the ductal system is smaller in the 
parotid duct. For small stones less than 4 mm in 
diameter in submandibular cases and less than 
3 mm for parotid cases [Figure 6], extraction is 
performed with custom designed wire baskets of 
various sizes [Figure 7]. In cases of bigger stones, 
a priori fragmentation is necessary, using a laser 
system [Figure 8], or possibly an  extracorporeal 
lithotripter. Stenoses are treated with metallic 
dilators or with balloon catheters. All these 
techniques of fragmentation and stone retrieval are 
performed under endoscopic control, as described 
by others.21 We do not recommend the “semi-blind” 
technique, consisting of introducing the basket  
after the removal of the optic fibre, because of its  
lack of precision and the potential danger of 
perforation. In recent published studies, the overall 
success rates were above 85%.17,1,22 It is important to 
keep in mind that a combined endoscopic-external 
approach may be required in cases with larger 
size stones especially the ones positioned deeper 
in the salivary ducts and not easily retrievable or 
fragmented by laser.

Figure 3: Diagnostic and interventional Marchal 
sialendoscope (inset – wire basket and laser fibre)

Figure 4: Endoscopic view shows the salivary ductal 
system (main duct, secondary and tertiary branches)



Rashid Al-Abri and Francis Marchal

Technical Note | 385

Technique Indications and 
Contraindications
The indications for sialendoscopy are all salivary 
gland swellings of unclear origin.23 There are 
no specific contraindications, mostly because 
sialendoscopy is a minimally invasive outpatient 
procedure performed under local anaesthesia. All 
ages can benefit from this technique.24,3 

The interventional sialendoscopy is a  
technically challenging procedure. Operating the 
rigid sialendoscope is delicate, requires experience 
and might be hazardous due to the theoretical 
risks of perforation and vascular or neural damage. 
Progression in the canal should be performed only 
under adequate vision. Perforations of iatrogenic 
origin can lead to diffuse swellings of the floor of 
mouth, with potential risks of life-threatening 
swellings.

Operative Technique
Sialendoscopy can be done as an outpatient 
procedure with the patient sitting in a chair or 
partially recumbent. Anaesthesia is purely local, 
but occasionally general anaesthsia (GA) may be 
required for some cases. Progressive dilatation 
of the papilla is performed with salivary sounds 
of progressively larger diameters. Endoscopy is 
performed with progressive endoluminal irrigation 
using a local anaesthetic solution and, if GA is 
administered, irrigation is performed using normal 
saline solution.

Limitations
The writhing course of the canal puts certain 
limitations on semi-rigid endoscopy, especially 
in cases of sharply bent curvatures. Also,  
manoeuvering within the small salivary ducts has 
to be absolutely atraumatic because of possible 
ductal perforation of yet uncertain consequences. 
Significant trauma to the ductal wall could result 
in later stenosis. Marsupialisation of the ductal 
papillae should either be completely avoided, or 
kept as small as possible to prevent retrograde 
passage of air and aliments.

Efficacy  
In the reviewed literature, the procedural success 
rate of sialendoscopy (resolution of obstruction) 
ranged from 82% (90/110)25 to 87% (47/54).26 
In a study of 72 patients, 8% (n = 6) had clinical 
or subjective problems which did not improve 
after the procedure and required removal of the 
gland. In another study of 129 patients, 110 of 
whom underwent interventional sialendoscopy, 
sialendoscopy treatment in 18% (n = 20) of 
patients was considered a failure, with five patients  
requiring gland resection.25 Recurrence of 
obstructive symptoms were reported in two other 
studies with rates of 2% (4/236)27 and 5% (3/55),17 

respectively. All recurrences occurred between  
15 and 24 months after the procedure.

 
Figure 5: Endoscopic view demonstrates the presence of a 
mucosal plug in a salivary gland ductal system Figures 6: Stone being removed by use of a wire basket



New era of Endoscopic Approach  
for Sialolithiasis: Sialendoscopy

386 | SQU Medical Journal, December 2010, Volume 10, Issue 3

Safety
Few complications were reported in the reviewed 
literature. The most common complication reported 
by patients following sialendoscopy was temporary 
swelling of the gland. In one study of 129 patients,25 

ductal wall perforation occurred in 11 patients (9%), 
with two of these patients requiring hospitalisation 
and one patient undergoing gland resection. Three 
other studies reported cases of perforation with an 
incidence of 3/55,17  1/103,28 1/23627 respectively. 
One patient (1/236) suffered from lingual nerve 
paraesthesia caused by the perforation, and ductal 
strictures were also reported in seven patients in 
a case series study of 236 patients.27 Five of these 
underwent successful dilatation with two requiring 
further surgery. Other complications included wire 
basket blockages, infection and ductal avulsion. 

Conclusion
As the most frequent ductal pathology is  
sialolithiasis, interventional sialendoscopy 
aims to retrieve salivary stones following their 
fragmentation and allows almost complete 
exploration of the ductal system (main duct, 
secondary and tertiary branches), mainly because 
of the small diameter of the scopes (0.9 and 1.3 
mm).18 Diagnostic sialendoscopy is a low morbidity 
minimally invasive technique, which becomes the 
investigational procedure of choice for salivary 
duct pathologies in all ages and especially in elderly 
patients with concurrent diseases. Interventional 
sialendoscopy allows the treatment of sialolithasis 
and stenosis, and help therefore to prevent salivary 
gland excisions and to minimise postoperative 

complications. Finally, it should be noted that in the 
early phases of sequential learning complications 
rates are significant. However, major complications 
are infrequent and in general can be rectified by 
standard salivary gland surgery.29

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