Salivary Endoscopy




Introduction


Salivary endoscopy is a minimally invasive technique for the treatment of a variety of inflammatory salivary gland pathologies. The procedure has been in practice globally since the early 1990s. The small high-resolution telescopes are in their fifth generation of development and now incorporate rinsing and instrumentation capabilities. The technique is useful for removing calculi and treating stenosis, as well as for inflammatory conditions such as Sjögren’s syndrome, recurrent juvenile parotitis, and for the secondary effects of radioactive iodine on the major salivary glands.


Patients most commonly present with meal-time obstructive symptoms of swelling of the gland and discomfort with provocation. The inflammatory processes can have more constant symptoms not associated with meals.




Key Operative Learning Points





  • The dilation of the papilla of the submandibular gland (SMG) and parotid gland is the initial rate-limiting step and requires delicate handling of the tissue.



  • The SMG duct is difficult to access via the papilla but very easy to navigate with the salivary endoscope.



  • Although the papilla of the parotid is relatively easy to dilate, the challenge is where the duct curves around the masseter muscle. Straightening the duct helps to facilitate this part of the endoscopy.



  • The scopes range in size from the diagnostic scope (0.8 mm) to therapeutic scopes (1.1 to 1.6 mm).





Preoperative Period


History





  • History of present illness




    • Duration of symptoms



    • Age at onset



    • Provocation with meals



    • Previous history of calculi



    • Dry eye and/or dry mouth




  • Past medical history




    • History of radioactive iodine



    • Previous surgery of the salivary gland



    • Medical illness



    • Family history



    • Medications:




      • Anticoagulants





Physical Examination





  • Palpation of all major salivary glands



  • Intraoral examination including examination under the operating microscope




    • Notation of size and location of the papilla particularly of SMG



    • Observation of quality and quantity of expressible saliva



    • Palpation for calculi along Wharton’s duct



    • Palpation for calculi at or near the papilla of Stensen’s duct



    • Evaluation of potential surgical challenges to the procedure




      • Teeth



      • Tori



      • Piercings





Imaging





  • Ultrasound (US) is the primary imaging modality outside of the United States and is becoming more popular in the United States. US is able to detect calculi as small as 2 mm and is very good at demonstrating ductal dilation associated with any form of obstruction. It is also a dynamic study and can be done with concurrent salivary stimulation with food. It is also possible to do the study with intraoral palpation to further delineate calculi. The most difficult area to image is the anterior aspect of Wharton’s duct.



  • Computerized tomography (CT) without contrast is very good at identifying calculi larger than 1 mm. It is not useful for most cases of stenosis unless the duct is dramatically dilated. Contrast should be used in cases where a neoplasm remains in the differential diagnosis.



  • Sialography




    • Conventional sialography is invasive and very operator and interpreter dependent, but it can be useful in some difficult to understand cases of obstruction.



    • MRI sialography is available in a few centers. No contrast is required because the saliva is used as contrast. It is expensive and has all the limitations of normal MRI. It requires extra back table work and programming to acquire the images.




Indications





  • Obstruction of the salivary glands by history and imaging compatible with calculi or stenosis



  • Inflammatory conditions significant enough to warrant operative intervention due to frequency and severity



  • Symptoms related to administration of I 131



Contraindications





  • Salivary endoscopy during an acute infection is a relative contraindication with the possibility of worsening the infection or perforating the duct.



  • Medical comorbidities should not be a contraindication because most of these procedures can be done using local anesthesia alone or with awake sedation.



Preoperative Preparation





  • Preoperative antibiotics if necessary to control an acute process





Operative Period


Anesthesia





  • General: Although this procedure can be done using local anesthesia or with awake sedation, general anesthesia is often preferred for patient comfort. For some hybrid procedures and bilateral cases, nasal intubation may provide better exposure in the oral cavity.



  • Awake sedation is possible.



  • Local anesthesia, including office salivary endoscopy, is possible in some situations.



Positioning





  • Supine: The patient is positioned the same as any endoscopic sinus procedure with the head turned slightly toward the surgeon.



Perioperative Antibiotic Prophylaxis


Not all surgeons use perioperative or postoperative antibiotics for a routine type of procedure. However, if there has been recent infection or for a combined approach with some degree of opening through the mucosa combined with an endoscopy, antibiotics are recommended.




  • If combined approach through a face lift incision is used to address parotid pathology, then a first-generation cephalosporin is used.



  • Clindamycin if the patient is allergic to penicillin



  • Patients having transoral hybrid procedures receive amoxicillin/clavulanic acid.



Monitoring





  • For combined approaches to the parotid gland and Stensen’s duct, some surgeons use facial nerve monitoring. There is no evidence that it improves outcomes, and we do not use such monitoring.



Instruments and Equipment to Have Available





  • Camera and light source tower for endoscopy



  • Basic salivary endoscopy set with mouth props, dilators of multiple types, and delicate scissors and forceps



  • Retractors including sweetheart, malleable, and self-retraining



  • 20-cc syringe with saline



  • Irrigations with intravenous (IV) connecting tubing



  • Multiple salivary endoscopes of different dimensions (1.1, 1.3, and 1.6 mm) for different pathologies



  • Disposable instruments including stone baskets, balloons, dilators, and stents



  • Kenalog



  • Local anesthesia if the case is not under general; local without epinephrine can be used as the irrigation fluid instead of saline to stent the duct open to perform the procedure



Key Anatomic Landmarks





  • Internally the SMG papilla is located posterior to the anterior incisors, although its exact location is variable and should be noted in the office while stimulating the patient’s salivary glands with food.



  • The parotid papilla is adjacent to the second molar in the buccal mucosa.



  • Stensen’s duct is in close proximity to the buccal branch of the facial nerve.



  • Calculi in the hilum of the SMG are close to the lingual nerve, which frequently has to be moved laterally for hybrid approaches to an SMG calculus.



Prerequisite Skills





  • Endoscopic skills



  • Basic open head and neck surgery skills



  • Patience



Operative Risks





  • Failure to retrieve the calculus or eliminate the pathologic process



  • Perforation of the duct by penetrating the duct with the scope



  • Avulsion of the duct by pulling too hard on an impacted calculus



  • Blocked basket requiring an open procedure to retrieve the basket stuck on a salivary calculus



  • Stenosis of the duct from instrumentation, laser thermal injury, or combined approach incisions



  • Airway obstruction from irrigation



  • Cranial nerve injury to the lingual or buccal branch of the facial nerve during hybrid procedures



  • Bleeding from an injured vessel. No risk of these during purely endoscopic procedures



  • Failure of the procedure and the need for excision of the salivary gland



Surgical Technique





  • Salivary endoscopy



Submandibular Gland





  • Patients are selected for local, monitored anesthesia care, or general anesthesia based on patient factors, pathology, and comorbidities.



  • Visualize the papilla with magnification.



  • Saliva milked from the gland is a useful landmark but is of limited quantity and must be used sparingly.



  • Do not use toothed forceps or instruments that can create a dimple in the mucosa simulating an orifice.



  • Atraumatic dilation technique with rigid dilation progressively or with Seldinger technique ( )



  • Choose scope size based on expected pathology and instruments that fit through each port.



  • Check scope for optics, focus, and white balance, and determine the direction of up while holding the scope in your hand outside the patient so that you will know this direction during the endoscopy.



  • Irrigate both ports of the scope with saline to avoid air bubbles.



  • Insert the scope without force.



  • Use appropriate stone (calculus) baskets for size (more wires for smaller calculi and fewer for larger stones) ( ).



  • Stones larger than 4 mm in their smallest dimension that are not near the papilla will need either hybrid procedures or fractionation before retrieval.



  • Floating calculi are usually retrievable.



  • Most calculi require papillotomy for extraction ( ).



Parotid Gland








    • Identify the papilla near the second molar. These are usually easier to locate than the submandibular papilla.



    • Dilation using metal dilators



    • Scope set up as previously described



    • Realize that Stensen’s duct is smaller



    • Be aware that attempted endoscopic removal of calculus in the ductal system proximal to the masseter muscle has a low success rate.



    • Calculi larger than 3 mm that are not floating may need fragmentation or hybrid approaches.




  • Most stenosis tends to occur in the parotid ductal system.



  • Stenosis cases may be single diaphragmatic ideal cases or more difficult multilevel or severe cases.



  • A stenotic duct can be dilated by a balloon or scopes in sheaths ( Fig. 88.1 ).


Apr 3, 2019 | Posted by in OTOLARYNGOLOGY | Comments Off on Salivary Endoscopy
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