ACTA OTORHINOLARYNGOL ITAL 25, 145-149, 2005 ROUND TABLE 91ST NATIONAL CONGRESS S.I.O. Current opinions in sialolithiasis diagnosis and treatment Attuali conoscenze nella diagnosi e trattamento della scialolitiasi M. ANDRETTA, A. TREGNAGHI1, V. PROSENIKLIEV, A. STAFFIERI ORL Clinic, Department of Surgery; 1 Institute of Radiology, University of Padua, Italy Key words Parole chiave Salivary glands • Sialolithiasis • Diagnosis • Treatment • Ghiandole salivari • Litotrissia • Diagnosi • Terapia • Sialo-MRI • Lithotripsy Scialo-RM • Scialolitiasi Summary Riassunto The introduction, 15 years ago, of extracorporeal shock L’introduzione, 15 anni fa, della litotrissia extracorporea con wave lithotripsy in the treatment of salivary gland calculi, onde d’urto (ESWL) nella terapia della calcolosi salivare ha has changed the therapeutic approach in these patients. Aim cambiato radicalmente l’approccio terapeutico di questi pa- of this study was to evaluate the efficacy of lithotripsy in zienti. L’obiettivo del nostro studio è stato quello di valutare sialolithiasis, after 10 years follow-up. A review has been l’efficacia terapeutica della litotrissia nei pazienti con scialo- made of the literature to establish current opinions in diag- litiasi, tramite un follow-up a lungo termine (10 anni). È stata, nosis and treatment of sialolithiasis. The role of ultra- inoltre, effettuata una revisione della letteratura con lo scopo sonography, radiography and, in particular, of sialo- di valutare le attuali conoscenze riguardanti la diagnosi e la magnetic resonance imaging in diagnosis of salivary lithi- terapia di questa patologia. È stato, poi, valutato il ruolo del- asis has been evaluated. The greater efficiency of the extra- l’ecografia, della radiografia ed in particolare della scialo- corporeal shock wave lithotripsy treatment for parotid, RM nella diagnosi di calcolosi salivare. La maggiore efficacia compared to submandibular calculi, has been demonstrated della litotrissia è stata riscontrata nella calcolosi della ghian- (57% versus 33%). In 68% of our patients, lithotripsy was dola parotide, rispetto alla ghiandola sottomandibolare (57% resolutive after 10 years. Ultrasonograpy should be consid- vs. 33%). La litotrissia extracorporea è stata risolutiva in 68% ered first choice examination in diagnosis of salivary dei nostri pazienti, a 10 anni di distanza. L’ecografia si è con- calculi. Sialo-magnetic resonance imaging is a recent, non- fermata indagine di prima scelta nella diagnosi di calcolosi invasive diagnostic procedure with the advantage of no salivare. La scialo-RM è una metodica diagnostica non invasi- radiation exposure, and with better definition of anatom- va con il vantaggio di non esporre a radiazioni ionizzanti e che ical and functional state of glandular parenchyma and duct, offre maggiori indicazioni anatomo-funzionali riguardo alle compared to other available techniques. ghiandole salivari e al loro asse escretore, rispetto alle altre metodiche disponibili. Introduction gland is affected in 2% of cases and other minor sali- vary glands in another 2% 2. Calculi generally consist The introduction, 15 years ago 1, of extracorporeal of a mixture of different calcium phosphates (mainly shock wave lithotripsy (ESWL) in the treatment of hydroxy-apatite and carbonate-apatite) together with salivary gland calculi, has changed the therapeutic an organic matrix. The aetiologic factors involved in approach in these patients. the sialolith formation can be classified into two dif- Salivary glands lithiasis (sialolithiasis) is the most ferent groups: on the one hand, saliva retention due common disease of the major salivary glands after to morpho-anatomic factors (salivary duct stenosis, mumps 2 and accounts for approximately 30% of all salivary duct diverticuli, etc.), on the other, saliva salivary disorders and about 0.01-1.0% of the popu- composition factors (high supersaturation, crystal- lation is held to be affected, with a higher incidence lization inhibitor deficit, etc.) 3. in males aged between 30 and 60 years 3-10. The most Until a few years ago, the treatment of salivary common localization is the submandibular gland stones consisted in medical and surgical procedures. where 92% of calculi are found, the duct being more The surgical procedure shows greater efficacy in the frequently affected than the parenchyma. The parotid elimination of stones, compared to medical therapy gland is affected in 6% of cases. The sublingual (in most cases with poor results), but with not indif- 145 M. ANDRETTA ET AL. ferent, post-operative, complications observed in weighted; second – the sialographic part – acquired some cases. The innovative (conservative) therapeu- with cholangiographic derivation sequences, op- tic methods consist in extra-corporeal lithotripsy, in- portunely modified and adapted, with a volumetric tra-cannular lithotripsy and interventional sialen- and multi-slice 2D acquisition, then 3D recon- doscopy. structed. After positive experience in the treatment of urinary and pancreatic calculi, extra-corporeal shock wave lithotripsy (ESWL) is proposed as an alternative Results therapeutic approach in the treatment of salivary stones in the early 90s. Data concerning site of salivary stones, results of The aim of this investigation was to evaluate the ef- lithotripsy and clinical evolution of our patients over ficiency of ESWL, with long-term follow-up study a 10-year follow-up period, are outlined in Table I*. (10 years), in patients submitted to ESWL treatment None of these patients reported any kind of compli- for sialo-lithiasis and also to determine the role of ul- cations during or after treatment. trasonography, radiography and, in particular, of sia- None of the 13 patients (68%) presented further lo-magnetic resonance imaging (MRI) in the diagno- episodes of sialo-lithiasis during the 10-year follow- sis of salivary stones. up period and continued being asymptomatic for 10 years after lithotripsy. The remaining 6 patients un- derwent different treatments: 2 continued sessions of Materials and methods lithotripsy in another hospital, 3 patients underwent an operation of marsupialization of Wharton’s duct, A total of 19 patients (11 male, 8 female) with sali- and 1 patient underwent sialectomy of the sub- vary calculi (12 submandibular and 7 parotid), age mandibular gland due to persistence of hilar calculus range 14-70 years (mean 40), were observed at a dis- 1.5 cm in diameter. tance of 10 years, after ESWL treatment. ESWL was performed using a Minilith SL1 (Storz- Medical) with an electromagnetic shock wave Discussion source, equipped with a coaxial 7.5 MHz frequency ultrasound (US) transducer. Patients were treated in 4 US with high frequency linear transducer (10-13 MHz) sessions (20 minutes each), with 1200 impulses per is first choice investigation for diagnosis of salivary session. stones. Submandibular and parotid calculi diagnosis US with a high frequency (10-13 MHz) transducer can be readily performed with US, for almost all intra- was performed in all patients. parenchymal stones. US sensibility decreases for duc- Moreover, patients underwent sialo-MRI, for tal and, in particular, for papillary stones. Finally, di- which a one Tesla super conductive Tool, (Siemens agnosis of salivary calculi is correctly performed in > Harmony), equipped with a Head coil, was used. 90% of cases, with the 10-13 MHz US transducer 11. The sialo-MRI examination consisted in two parts: ESWL can be performed in all calculi visualized by first – the morphological part – acquired with 5 mm US, since the exact location of the stone(s) can be de- coaxial scan slices, a gap of 0.5 mm T1 and T2 termined during the ESWL session 12. Tabl. I. Location of salivary calculi and follow-up over 10 years. ESWL Submandibular gland Parotid gland Total 12 (63%) 7 (37%) 19 Duct Parenchyma Duct Parenchyma 10 (83%) 2 (17%) 5 (71%) 2 (29%) Complete disintegration 3 (30%) 1 (50%) 3 (60%) 1 (50%) 8 (42%) Partial fragmentation 7 (70%) 1 (50%) 2 (40%) 1 (50%) 11 (58%) 10-year follow-up: asymptomatic patients 6 (60%) 1 (50%) 5 (100%) 1 (50%) 13 (68%) Note: (%) 146 MAJOR SALIVARY GLANDS PATHOLOGY The two formal contraindications are pregnancy and failure of US detection of the stone 13. Before treat- ment, a radiographic examination can be performed, considering that stones are radio-opaque in > 80% of cases 11. In this study, we propose a sialo-MRI exam- ination in the diagnostic workup of sialolithiasis. Sia- lo-MRI is a diagnostic, non-invasive, method recent- ly introduced, with promising results, in the evalua- tion of salivary gland disease. This technique pro- duces sialographic images but without contrast medi- um injection and without the disadvantage of ioniz- ing radiation (CT and contrast sialography). An im- portant advantage of sialo-MRI is the fact that the structural anatomy of the salivary glands remains un- changed with this technique, which allows an exact delimitation of the glandular acini and duct (Fig. 1). In US, the acini and ducts may be compressed by the US transducer, moreover, in sialography, the acini and ducts can be dilated by contrast medium injec- tion 14. The Sialo-MRI study consists of two parts: i. anatomical – which also contributes to determine the relationship with adjacent structures thanks to its di- mensional, morphological and structural examination of the parotid and submandibular gland (Fig. 3); and ii. sialographic – which shows only the ductal com- Fig. 2. Sialo-MRI of parotid gland with remarkable dilata-