Minimally Invasive Techniques for Benign Salivary Gland Obstruction
Total Page：16
File Type：pdf, Size：1020Kb
ENT FEATURE Minimally invasive techniques for benign salivary gland obstruction BY JACKIE E BROWN AND ROSE NGU Salivary gland obstruction is a common condition – it is recognised by a complaint of intermittent meal-time swelling of the affected salivary gland and can be accompanied by recurrent infections. Imaging can identify the nature and location of an obstruction but has more recently been used to guide minimally invasive techniques in the treatment of benign salivary gland obstruction. Introduction Obstruction of the major salivary glands and associated infection is the most common cause of salivary gland complaints, resulting in hospital admission for up to 59 cases per million inhabitants in the UK [1]. Salivary stones are the most common cause of obstruction. A recent study revealed that 73.2% were due to salivary stones while 22.6% were caused by salivary duct stricture formation [2]. Post-mortem studies have shown salivary stones in 1.2% of the population but it is likely that micro-calculi are formed continuously and mostly expelled spontaneously. Occasionally a stone becomes trapped, develops to cause mechanical obstruction and promotes infection. Dehydration and pre- existing sialadenitis may be promoting Figure 1: Salivary stone lithotripter in place for treatment of a parotid stone. factors. Stones develop mostly in the submandibular glands (80-90%) but spontaneously following sialogogues infection, surgical sialadenectomy 5-20% form in the parotid glands. and gland massage or are released by becomes more hazardous and nerve Salivary duct stenosis is a narrowing papillotomy. More proximally placed damage increasingly likely. of the duct lumen sufficient to reduce stones have required sialadenectomy. egress of saliva at peak flow. Of cases Gland removal is accompanied by Minimally invasive exhibiting strictures, 22.6% may be a recognised level of morbidity, techniques in salivary point or diffuse, single or multiple; which includes the risks of general obstruction 75.3% are found in the parotid glands anaesthesia and the morbidity A minimally invasive approach and they are three times more common associated with surgery, such as avoids the need for surgical removal in middle aged women [2]. haemorrhage, neurological damage of the gland with its accompanying (hypoglossal and lingual nerves complications and yet removes the Traditional management following submandibular gland symptomatic obstruction. In addition, options removal, and risks of facial nerve palsy it reduces demand on inpatient Conventional treatment options following superficial parotidectomy), facilities as procedures are invariably have been determined by the scarring, cosmetic defects, and other performed on an outpatient basis. location and nature of the salivary sequelae of surgical intervention Further, normal secretory function gland obstruction. Salivary stones including infection, fistula formation may be restored, allowing the long- in the distal ductal system may be and Frey’s syndrome. When stone term retention of a viable salivary managed conservatively; many pass formation is complicated by chronic gland and reducing the possibility of ent and audiology news | MAY/JUNE 2014 | VOL 23 NO 2 | www.entandaudiologynews.com ENT FEATURE developing a chronically dry mouth [3, and Marchal have each reported 4]. A scintigraphic study assessing the 82-87% success in clearing suitable recovery of gland function following sialoliths [7, 8]. surgical stone release from the More recently intracorporeal submandibular duct demonstrated lithotripsy has been described. Here improvement in radioisotope laser, piezoelectric or electrohydraulic uptake over a three-month period energy is applied directly to the postoperatively, supporting the surface of a salivary stone visualised in argument that salivary glands may the salivary duct through a dedicated recover function following clearance sialendoscope [9]. of an obstruction [5]. Limited access surgery Salivary stone lithotripsy A form of minimal-access intra-oral This procedure uses piezoelectric surgery has been developed to treat Figure 2: Image seen down a sialendoscope while capturing a stone in a basket. or electromagnetic shockwaves large palpable proximally-placed – targeted transcutaneously by stones in the region of the posterior ultrasound through a fine therapy part of the submandibular duct, the Treatment of salivary calculi beam – to break down salivary calculi region sometimes referred to as by interventional sialography over a number of visits (Figure 1). The the ‘comma’ or ‘genu’ area. This is a Miniature Dormia baskets can be procedure is relatively painless and frequent site of impaction for larger inserted into the major salivary ducts will break calculi in around 2-6 visits stones and traditionally has been under x-ray or ultrasound guidance and in 39-65% of cases, dependent on treated by surgical removal of the manipulated to pass and grasp small stone size and location. The greatest whole submandibular gland. stones. The procedure is performed success has been achieved with Surgical stone removal from the under local anaesthesia (by direct stones less than 7mm diameter and submandibular gland is now possible infiltration of the buccal oral mucosa in the parotid gland. Stone fragments via an intra-oral approach, performed or inferior dental nerve block). The may be expelled spontaneously but under local or general anaesthesia. trapped stone is then withdrawn to the require a patent distal duct, or may The submandibular duct is identified duct ostium, where a small relieving be extracted by Dormia basket (see through an incision in the floor of papillotomy incision may be needed later). mouth and traced posteriorly to the to release the stone. It is important site of the large calculus. The lingual to maintain regular salivary flow Sialendoscopy and nerve, passing over the submandibular through a papillotomy site, if this has intracorporeal lithotripsy duct at this point, is identified and been necessary to release a stone Ultra-fine rigid, semi-rigid or flexible retracted, before a relieving incision in during extraction in a Dormia basket, endoscopes of 1.3-0.9mm diameter, the duct releases the stone. The duct in order to prevent healing over of with or without working channel, is then repaired and the wound closed the duct orifice. This may be done are inserted atraumatically assisted [10, 11]. This has been effective as a cure by prescribing regular hydration and by irrigation, and under local in 96% of cases, where the stone is use of sialogogues, assisted by gland anaesthesia. This can demonstrate directly palpable in the posterior floor massage. stones, duct wall changes, duct of mouth. Case selection is best performed on strictures and sphincter phenomena, the basis of preoperative sialography. and interestingly has detected salivary Interventional sialography Ideally the stone should be within stones undetectable by any other Interventional sialography enables the main extraglandular duct, mobile diagnostic tool in 20% of symptomatic access to the proximal portion of the and no more than 20-25% wider than cases of unclear diagnosis [6]. main parotid and submandibular the distal duct running from stone to Miniature Dormia baskets, graspers ducts for instrumentation in the ostium [12]. (to grasp and crush stones prior to treatment of obstruction by calculi Duct strictures lying between the removal) and balloons have been used and strictures. Sialography outlines stone and duct orifice may require through, or beside, the sialendoscope the duct morphology and localises the dilatation by balloon ductoplasty but to capture and extract stones, and obstruction, and subsequently provides should always be viewed with caution as dilate strictures (Figure 2). Nahlieli the route-map for intervention. they are invariably densely fibrotic and Figure 3: (A) The preoperative sialogram identifying a stone in the middle third of the submandibular duct. (B) The insertion of a Dormia basket (closed). (C) The stone trapped in the open basket. ent and audiology news | MAY/JUNE 2014 | VOL 23 NO 2 | www.entandaudiologynews.com ENT FEATURE Figure 4: (A) Sialogram showing multiple stenoses located in the parotid duct before treatment. (B) Appearance on sialogram following balloon dilatation. may still impede stone removal. apparent. Many of these techniques 7. Marchal F, Dulguerov P, Becker M, et al. Submandibular diagnostic and interventional Success in clearance of stones using compliment each other so that where sialendoscopy: new procedure for ductal Dormia baskets is reported to range from one is partially successful, a further disorders. Ann Oto Rhinol Laryn 2002;111(1):27-35. 60-100%. This technique therefore offers technique may complete the clearance of 8. Nahlieli O, Shacham R, Bar T, Eliav E. Endoscopic mechanical retrieval of sialoliths. Oral Surg Oral a simple, effective, highly non-invasive a stone. A study examining the outcome Med O 2003;95(4):396-402. cure which is achievable in one visit with of minimally invasive management of 9. Iro H, Zenk J, Hosemann WG, Benzel W. minimal morbidity. In avoiding general salivary calculi using single and, where Electrohydraulic intracorporeal lithotripsy of salivary calculi. In vitro and animal experiments. anaesthesia it offers treatment options necessary, combined Comment. HNO 1993;41(8):A12-3. to patients with other more serious co- minimally invasive techniques in 10. McGurk M, Makdissi J, Brown JE. Intra-oral removal morbidities. 4691 patients