Around 1.3% of the population has one or more salivary lithiasis.
76% of these lithiasis are localized in the submandibular glands, 22% in the parotid glands and 2% in the sublingual glands.
Surgery was the only available treatment.
We will describe the two new non-surgical therapies.

This pathology appears at any age, from 3 to 85 but the average age has been estimated to be 44.
Lithiastatic pathology is usually revealed by signs and symptoms which can be equally painful as those occurring in salivary colic, most frequently just before or during meals, causing violent pain in the area of the affected gland, and hampering eating. Analgesics and antispasmodics should be administered as soon as possible.
In other cases, the painless swelling of the salivary gland or salivary herniation, occurs during the course of a meal. The gland remains swollen for a few hours, then slowly empties and the process begins again with the next meal.
In other cases, the pathology is discovered during routine X-rays and maxillary panoramic tomography.
The pathology is equally divided between the sexes.
These different pathologies must always call for a consultation with a clinician who will quickly diagnose salivary lithiasis.

LITHIASIS FORMATION

It is admitted as a rule that lithiasis develop following a period of inflammation of a salivary gland, it is accompanied by a slowing down of the secretion of saliva.
A thick mucus, and in certain cases, even a purulent salivation may occur, the latter stagnating within a minor duct.
This pathological formation coats itself with and gives birth to a lithiasis.

The only treatment of salivary lithiasis before the development of endoscopy and lithotrypsy was surgical. It consisted of the removal of the stone, using various methods, depending on the salivary gland involved.

The only procedure was superficial parotidectomy, with conservation of the facial nerve if the stone was located in the gland or in Stenon's Duct as far in as one third of its frontal part. This delicate operation was performed under general anesthesia and often caused temporary facial paralysis. The average hospital stay varied from 5 to 7 days. It is for this reason that often patients were left to cope with their painful crisis, in order to wait for the stone to migrate towards the ostium. The consequence of this wait was often the partial destruction of the salivary gland through chronic infection.

At the level of submandibular glands :

Surgeons had several options. If the stone was located behind the ostium of the excretory duct, a simple sphincterotomy under local anesthesia allowed the stone to exit.
If the lithiasis was blocked in the duct's median part, a precise dissection of the duct had to be done, taking great care not to injure the lingual nerve. This procedure was performed under local or general anesthesia, but was very painful post-operatively.
Finally, in the event the stone was located in the gland's pelvis and the sub-maxillectomy was the only issue, under general anesthebnsia, taking care to perfectly dissect the chin branches of the facial nerve. The average hospitalization was 3 to 5 days. Post-operative sequelae were simple.

Technically, all of these endoscopies were performed with the help of flexible ultra fine "Olympus" endoscopes of 0.4, 0.8 and 1.1 mm.
For the last 10 years we have used the same protocol.
First, we locate the lithiasis. Preliminary imaging is obtained without any special preparation, it includes a full frontal or profile X-ray, or better, a panoramic tomography of the maxillaries.
Next, an intra buccal occlusal image showing the submandibulars and the stones located in the excretory ducts.
An echography of the salivary glands is then performed in order to visualize the glandular parenchyma, and determine whether there is a glandular pain or glandular atrophy due to chronic infections.
Finally, sialography is performed with a simple injection through the duct up to the obstruction to obtain the diameter of the excretory duct and it's degree of dilation.

If all of the above conditons are met, i.e., a permeable excretory duct, a mobile lithiasis in the duct, and a non-atrophied, operational salivary gland, then we would opt for performing a fibroscopy.

After a simple dilatation of the ostium, the introduction of the fibroscope is effected with the aid of nontraumatic calibrated probes.
We are presently using exclusively a flexible endoscope of 0.8 mm in diameter. Over the past ten years, we have tested many diameters of endoscopes among which : 0.4 mm, and 1.1 mm with an working channel of 500 microns, which allowed the use of a laser catheter of 300 microns. In this manner, we were able to attempt to perform intraduct lithotrypsies with a dye pulse laser.
Because of the extreme fineness of the endoscopic material, the guiding is entirely done by hand, maintaining contact with the fibroscope externally.
No anesthesia is necessary for this totally painless examination.

The removal of salivary gland stones by fibroscope began in April of 1990, after the development of a small basket probe of 0.8 mm in diameter. The basket was inserted blindly into the glands excretory duct, it was not possible to keep the fibroscope in place due to the narrowness of the salivary ducts.

Beginning in December 1988, at first, 66 supposedly normal salivary glands (34 submandibulars, 32 parotids) were examined after sialography. This was done in order to obtain the endoscopic anatomy of the salivary ducts of the submandibular and parotid glands.

Later, we conducted fibroscopies on 784 pathological glands:

• 546 glands with a lithiasis, or 70% (397, or 50% in submandibular glands, and 149 in parotid glands, or 19%).

• 218 glands with pathologies, with 28% presenting intrinsic or extrinsic duct compressions due to stenosis, lymph nodes, or expansive tumoral processes.
  

A total of 882 endoscopies were performed in 10 years.

The division was equal between the sexes and ages varied between 5 and 71 years. (avg 38)
This examination was always performed on ambulatory patients, and without interfering in their jobs.

During an 8 year period, 491 lithiasis were removed by natural methods (401 submandibulary lithiasis, or 83%; of which 312 were single stones, and 89 multiples of 2 to 6 stones; 90 parotidian, or 17%, of which 85 were single stones, and 5 were mutiples), representing 90% of all examined lithisiatic glands.

In this total of endoscopies, we were able to perform 26 endosopies on children between the ages of 5 and 13 who presented salivary lithiasis, and removed 23 submaxilliary and 3 parotid lithisasis while under endoscopy, with local anesthesia of the ostium of Wharton's or Stenon's Duct, and without postoperative pain.

There was a failure rate of 32, or 3.6%.
- The Wharton's duct was too small in 19 submaxilliary glands, and for 13 parotid glands it wasnt possible to pass through the masseter elbow of Stenon's Duct.

Endoscopy allowed a visualization of 52 radio transparent microlithiasis (7% of the glands with pathologies), not perviously visible on conventional x-rays.
Fibroscopy supported the physio-pathological mechanisms of patients with chronic parotid problems due to the absence of a small valve normally located at the junction of Stenon's Duct and the pelvis, preventing the endo parotidian salivary reflux.

Endoscopy should be performed in the gentlest possible manner to prevent duct or glandular perforation. The passage of an obstacle must be performed after having examined the duct walls to assess the degree of inflammation at this level, and their elasticity to allow the passage of the endoscope. All brusque movements should be avoided.

In as much as the removal of a lithiasis is concerned, one single incident was noted in 1992, due to the basket catheter becoming blocked, after having clamped the stone in the pelvis of the parotid gland, level with the junction of the Stenon's Duct with the gland. The probe was left in place, and a superficial parotidectomy with conservation of the facial nerve was performed later.
Salivary lithiasis extractions must not be performed until a careful assessment has been made of the stone, the size of the excretory duct and its degree of elasticity in relation to the stone allowing the passage of a foreign body through natural channels.
Indeed, once the stone has been caught in the miniature basket probe, it will not be possible to release it in the duct, the narrow walls keep the stone in place no matter what motions are made with the probe. The major risk is removing the gland surgically because the miniature basket probe is blocked, whether in the pelvis, or in the main duct of the gland.

With the development of extra corporal lithotrypsy through electromagnetic shockwaves, this type of incident diminishes, the fragmentation of the lithiasis into small particles allows for its spontaneous elimination through the ostium of the gland.

Salivary gland endoscopy has become a simple, painless examination, that allows the in vivo approach of the pathology, and presents a reliable alternative to surgery.

Methods and Material

Pinpointing with an echographic probe of 7.5 Mhz, allows for an exact location of the lithiasis, and focalization of the electromangetic shockwaves on the stone to be fragmented.
The residue is spontaneously evacuated by saliva in the excretory duct, or removed under micro video endoscopy with the miniature basket probe catheter.

Lithotrypsy can be utilized on all stones found in submandibular or parotid salivary glands, with the exclusion of all lithiases in endo-oral surgical surroundings, without risk of lesions, at either the level of the lingual or facial nerves.
The size of the lithiasis is of little significance. These can vary from 1 mm to 3 cm, but its echographic location must be perfect.
There must be no intraglandular infection, and if necessary, antibiotics should be administered 8 days prior to the lithotrypsy.

Sialography remains the radiological examination of choice and reference before any therapy can be initiated. It is effectively the only one capable of indicating the caliber of the salivary gland's excretory duct. If the duct is too small (less than 1 mm) to allow the evacuation of lithiasic fragments, the only treatment available is surgery.
Scanners and MRIs are not used in these cases as they only supply limited information as to the glandular canal network.

In regards to blood dyscrasias, all hemostatic disruption contraindicates lithotrypsy. In these cases, anti-coagulants must be stopped 24 hours before the procedure.

Again, considering the extreme fragility of the salivary glandular parenchyma, which cannot accept trauma, we advise against all lithotrypsies, or attempts at lithotrypsy while using equipment not specifically adapted for this use, such as renal lithotrypsy tables, that have neither the pinpointing capability for the stone's location, nor the fragmentation power, and on which the patients position is not adequate for an operation on the salivary glands and could cause irreversible lesions.

RESULTS

From July 1995 to April 1999, 400 patients were treated, divided into 198 males (49%) and 202 females (51%).
The age of the patient varied between 6 and 85, with a statistical average of 45.5 years.

• 262 (65.5%) presented a single or mulitple submandibulary lithiasis;
• 138 (34.5%°) a parotid lithiasis.
• 252 lithiasis (63%) were destroyed (164 submandibular (41%), 88 parotid (22%) .
• 148 (37%) were reduced in volume with residual fragments from 3 to 5 mm.
• 388 (97%) patients no longer present any painful symptoms of salivary colic at mealtime.

12 (3%) of the patients continued to have salivary colic;
8 (2%) underwent a submaxillectomy which revealed a blocking of the fragments at the junction of Wharton's Duct with the gland's pelvis, presenting a macroscopic aspect of chronic sub-maxilitis.
4 (1%) were placed on antalgesics, antibiotics and corticoid anti inflammatory therapies until their symptoms abated.
We can state that all the lithiasis were fragmented, whatever their sizes, in 100% of the cases.

Undesirable after-effects

Some temporary undesirable effects were observed in the course of the lithotrypsy:

• pettechiae at the tubes point of impact (144, or 36%);
• light pain associated with a swelling of the treated gland (90, or 22.5%);
• duct hemorrages spontaneously reduced (258 patients, or 64%).

In the 15 days following the treatment, we observed 36 cases of glandular infection that were treated by antibiotics and corticosteroids.
We emphasis the fact that no anesthetic was given, no major sedative prescribed, and we observed no permanent or temporary facial nerve lesion, at the level of the parotid glands.

CONCLUSION

This new treatment that is performed with the aid of a miniaturized lithotryptor, with electromagentic shockwaves under echographic control, permits us in the vast majority of cases, to avoid surgical intervention for patients suffering from the disorders resulting from salivary lithiasis.

DISCUSSION

Lithiasic pathology represents a benign attack on main salivary glands. The only available treatment was surgical, either by sub-maxillectomy, parotidectomy if the stone was located in the gland pelvis, or by dissection of the floor of the mouth to seek Wharton's Duct for stones located in the median of the submandibulary's excretory duct. These operations were performed under general anesthesia, with a resulting minimum hospitalization of 3 days, leaving a scar, and sometimes after effects on the branches of the facial nerve, requiring a convalescence of 8 to 15 days. Endoscopy and lithotrypsy reduce these operations to a strict minimum. It is also is a complementary diagnostic tool useful in determining the cause of infectious pathologies.

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