Facial nerve network & parotid gland  please place the mouse on the image

Salivary Tumours, Stones & Strictures

Benign Tumours

ECD or Extra-Capsular Dissection 

ECD is a specialist procedure that is not widely available. It was developed by Nicholson (Christie Hospital Manchester) in the 1950s but overlooked by the surgical community. Its application has been championed by Professor McGurk.   The main advantage of the operation is that it preserves most or all of the gland and reduces the risk of injury to the facial nerves. Patients leave hospital sooner and the risk of complications and side effects is significantly reduced.

Approximately 80 patients per million in the British population develop benign salivary tumours each year. The parotid gland is the most commonly affected site. 

Current Practice  - Superficial & Total Parotidectomy

The main risk with parotid surgery is an injury to the facial nerves that run through the Parotid Gland.  (Please pass the mouse over the diagram top left) The traditional operation for a benign tumour that lies above the nerve is a Superficial Parotidectomy (video left) and for a tumour lying below the nerve, a Total Parotidectomy.

If the nerve is damaged during surgery then varying degrees of facial paralysis result. The traditional operations mentioned above are more disruptive than the minimally invasive ECD procedure and carry greater risk of nerve damage. Another common side effect is Frey's syndrome where the secretory nerves from the damaged parotid gland join with the skin so the skin of the cheek sweats while eating. 

Total Parotidectomy also results in a hollowing of the cheek due to removal of the parotid gland.

Extra-Capsular Dissection ECD (video left)

ECD is less invasive than traditional operations, it can be performed through a smaller incision and the side effects are much reduced because the operation is less disruptive to the tissues. It is a much more conservative procedure with the same low risk of tumour recurrence (1-2% at 10y) as the traditional larger operations. However it has a significantly lower risk of side effects. (see table below - M McGurk published results - (pubmed Extracapsular dissection- minimal resection for benign disease BJOMS Jan 2011) M McGurk published results - (pubmed Extracapsular dissection- minimal resection for benign disease BJOMS Jan 2011)

Malignant tumours 

Incidence 

The incidence of malignant salivary gland disease is approximately eight patients per million population each year. Since they are uncommon, experience in dealing with them is vital and treatment has to be tailored to each person. In general the size of the tumour and its biological grade are important to outcome. Treatment is usually a combination of surgery followed by radiotherapy.
  
Treatment  

If a malignant salivary tumour is suspected, a thorough evaluation is indicated normally with CT/MRI scans and some form of biopsy.  Surgery is now more conservative when used in conjunction with post operative radiotherapy. In most instances the facial nerve can now be preserved. Treatment policy is mainly determined by the size of the tumour and to a lesser extent by its grade and site. Treatment is equally successful for the parotid, submandibular gland and mouth lesions.

Salivary Stones - New Minimally Invasive Methods of Treatment

The management of salivary stones has been revolutionised by European teams in London, Paris, Erlangen and Milan . The combined results of all the centres in more than 4,600 cases show that less than 3% of patients required salivary gland removal with 83% of stones retrieved.

However the current standard of care in most surgical units for stones in the submandibular or parotid gland is still gland removal with all the attendant risk to the associated nerves.

Baskets Small mobile stones of 4 - 5 mm can be removed with small wire baskets. (picture left and video left)

These baskets can be introduced through a small endoscope or under radiological control and patients are treated in the outpatient setting under local anaesthesia. The results are excellent with about 70%-75% of stones retrieved. 

Lithotripter Larger stones, (5-8mm) can be broken with a salivary gland lithotripter using ultrasound. The treatment is more effective for parotid stones (60% clearance) than submandibular (30%) so the treatment tends to be saved for parotid stones. 

Endoscope Assisted Submandubular Gland Surgery Fixed submandibular stones larger than 6mm are removed by an endoscope assisted surgical technique.  Under day care general anaesthesia, an incision in made along the floor of the mouth, the submandibular duct is found and traced back into the gland with the help of the micro endoscope. The stone is found and released. The operation takes about 30-40min. Results are excellent with stone retrieval rates of 97% 

Endoscope Assisted Parotid Surgery (video left)  Fixed parotid stones above 8mm are also removed by an endoscope assisted surgical method.  Under general anaesthesia an endoscope is introduced into the parotid duct. A small face lift incision is made in front of the ear to expose the parotid gland. The light on the end of the endoscope guides the surgeon on to the stone which is released, preserving the parotid gland. The operation takes about 1 hr. Stone retrieval rates are excellent, 97%  

Advances in optical instruments have made available micro-endoscopes (1mm diameter) that allow excellent visualisation of the salivary ducts. Micro-instruments can be passed through the endoscopes to target stones and strictures

Salivary Stricture  

   Incidence

In the group of patients that present with symptoms of obstruction (gland swells at mealtime) the cause is a salivary stone in 75% of cases but in the other 25% it is a stricture in the duct wall. The majority of strictures are in the parotid (75%) and more strictures occur in women than men. The cause of strictures is unknown. 
 
Traditionally there was no way of managing strictures apart from removing the salivary gland. 

   New Minimally Invasive Methods of Treating Salivary Strictures 
 
There are two approaches both provided in the outpatient setting under local anaesthesia

   Endoscope assisted dilation of stricture: 

An endoscope is introduced into the salivary duct. Mild strictures can be dilated flushing the duct with a saline solution under pressure. Tighter strictures can be opened will a small hand drill or by a small balloon that can be inflated within the stricture.   

   Radiological guided balloon dilation of the stricture: 

Under radiological control a thin catheter is passed into the duct then the balloon inflated to stretch the stricture. Successful dilation of the stricture is achieved in about 75% of cases. 

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