Salivary gland ductal obstructions are common, being the most frequent nonneoplastic salivary disorders in adults. Salivary calculi are the main cause of obstruction. Traditional and invasive transcervical sialadenectomy is still the most widely used treatment for perihilar and intraparenchymal obstructive salivary diseases worldwide despite the well-known morbidity related to its functional, neurologic, and aesthetic sequelae. However, improved radiologic imaging, better optical systems and endoscopic devices, and the introduction of minimally invasive therapeutic options have allowed the development of conservative gland-preserving techniques for managing salivary gland obstructions, including extracorporeal shock wave lithotripsy, operative sialoendoscopy, video-assisted transoral and transcervical stone removal, and ductal rehabilitation through interventional radiology and sialoendoscopy. Through adopting a minimally invasive and multimodal policy, a significant number (74%–100%, technique dependent) of salivary calculi can be safely and successfully retrieved while leaving an intact and functional salivary gland system. Only 2% to 5% of patients require gland excision. However, long-term follow-up evaluations of obstructive symptom recurrence are needed before the ultimate benefits of a gland-preserving conservative approach and the residual role of adenectomy can be assessed.
Obstructive sialadenitis is the major cause of salivary gland disorders, and accounts for approximately 50% of all benign disease. Patients typically present with the so called “meal-time syndrome.” Recurrent and painful periprandial glandular swelling is typical and may be complicated by bacterial superinfection indicated by a purulent papillary discharge.
Salivary gland obstruction may be caused by the presence of sialolithiasis, stenosis or anatomic variations in the ductal system, intraductal fibromucinous plugs, polyps, or foreign bodies, all of which impair physiologic salivary down-flow and lead to stasis. Sialolithiasis is still the main cause of salivary obstruction, and is detectable in more than 65% of cases. Between 80% and 90% of all cases of sialolithiasis affect the submandibulary gland, probably because of the intrinsic features of its secretion. The parotid gland is involved in only 5% to 10% of cases.
The second most frequent cause of salivary obstruction is duct disorders, mainly strictures and kinks that prevalently involve the parotid duct system (75% of cases), although other reported disorders include accessory ducts, sphincteric-like structures, pelvis-like formations, and intraductal evaginations. Salivary obstruction may also be related to the presence of intraductal mucous plugs, foreign bodies or polyps, sialodochitis, ab estrinseco compression from neoplastic masses or reactive intraparenchymal lymph nodes, or the granulation tissue associated with immunologic disorders (ie, Sjögren’s syndrome), but radioiodine therapy and ab estrinseco ostial compression by dentures (in the case of the parotid gland) have been also reported.
Invasive adenectomy has sometimes been favored because distinguishing the cause of mechanical obstruction based on a clinical assessment and traditional radiography, ultrasonography, conventional sialography, or CT is not simple and sometimes cannot be done.
Invasive surgery has also been justified based on a mistaken belief that the salivary gland obstruction is associated with an irreversible parenchymal inflammation that impairs salivary function, but this has been recently denied by scintigraphic and histopathologic findings of the secretory function recovery and histologic normalization after stone removal.
The introduction of new diagnostic tools has substantially improved diagnosis, with the incidence of idiopathic obstruction reduced to only 5% to 10% of cases. Ultrasonography is considered a valuable diagnostic technique, especially in the case of stones, but it has the limitation of being an operator-dependent procedure. Sialoendoscopy has recently partially filled a diagnostic gap because it allows direct visualisation. Dynamic MR sialography has also been proposed as a useful diagnostic procedure for salivary duct disorders and the preoperative evaluation of patients undergoing sialoendoscopy.
These modern diagnostic tools now make it possible to plan appropriate therapy based on the site and specific cause of the obstruction. Over the past 20 years, new and minimally invasive conservative therapies have been proposed, particularly for sialolithiasis, including extracorporeal shock wave lithotripsy (ESWL), operative sialoendoscopy, interventional radiology, the transoral removal of submandibular stones, and endoscopically video-assisted transcervical or transoral removal of parotid and submandibular stones.
Conservative treatment using sialoballoon dilatation under sialoendoscopic or radiologic fluoroscopic guidance is another useful technique. Minimally invasive gland preservation for salivary gland obstruction has greatly reduced the need for sialadenectomy. Conservative therapeutic options, alone or in combination, can preserve a functional gland in situ in 97% of cases. The published success rates of each of these techniques over the past 10 years are shown in Tables 1 and 2 .
| Author | No. of Patients | Site | Procedure | Success Rate | Residual Obstruction Rate | Sialadenectomy |
|---|---|---|---|---|---|---|
| Zenk et al | 231 | SM | Hilar transoral removal | 91% | 6% | 2% |
| Nahlieli et al | 12 | P | Endoscopically assisted removal | 75% | 25% | — |
| Marchal et al | 129 | SM | Sialoendoscopy | 85% | — | — |
| Escudier et al | 122 | P and SM | ESWL | 33% |
| 2% |
| Capaccio et al | 322 | P and SM | ESWL | 45% |
| 3% |
| Makdissi et al | 43 | SM | Hilar transoral removal | 97% | 5% | 2% |
| Zenk et al | 191 | P and SM | ESWL | 50% | 50% | — |
| Katz | 1773 | P and SM |
|
| — | 3% |
| McGurk et al | 455 | P and SM |
|
| 15% | 2% |
| Eggers and Chilla | 38 | P and SM | ESWL | 55% | — | — |
| Zenk et al | 683 | SM | Transoral removal | 86% | 14% | — |
| Nahlieli et al | 172 | SM | Sialoendoscopy | 94% | 4% | 3% |
| Iro et al | 4691 | P and SM |
| 81% | 17% | 3% |
| Author | No. of Patients | Site | Procedure | Success Rate | Residual Obstruction Rate | Sialadenectomy |
|---|---|---|---|---|---|---|
| Nahlieli et al | 236 | P and SM | Sialoendoscopy | 88% | 6% | 4% |
| Marchal et al | 55 | P | Sialoendoscopy | 85% | 15% | 1% |
| Ziegler et al | 72 | P and SM | Sialoendoscopy | 87% | 11% | 8% |
| McGurk et al | 8 | P | Endoscopically assisted removal | 100% | — | — |
| Brown | 348 | P and SM | Interventional radiology |
|
| — |
| Koch et al | 39 | P | Sialoendoscopy | 76% | — | 5% |
| Yu et al | 68 | P and SM |
|
| — | — |
| Papadaki et al | 94 | P and SM | Sialoendoscopy | 85% | 11% | 5% |
| Walvekar et al | 56 | P and SM | Sialoendoscopy | 74% | 21% | 2% |
Botulinum toxin therapy can be proposed in patients who have recurrent sialadenitis with no radiologic or sialoendoscopic cause of obstruction.
With this background, the residual indications for parotid and submandibular sialadenectomy for salivary gland obstruction in the era of ESWL and operative sialoendoscopy can be better assessed.
Is there a residual indication for sialadenectomy for salivary gland obstruction?
Until the 1950s, parotid gland excision for benign and inflammatory disorders was not considered a standard procedure. The following years saw a more aggressive approach, with total or near-total parotidectomy being advocated for treating chronic parotid sialadenitis. However, because total parotidectomy was associated with a significant rate of facial nerve injury, some authors suggested the use of superficial parotidectomy. In 1978, Casterline and Jaques reported that “near total parotidectomy with removal of the parotid duct can be performed safely and should be the procedure of choice in patients with chronic, relapsing parotid sialadenitis.”
More recently, Bates and colleagues suggested the usefulness of total or near-total gland resection as an effective and low-morbidity procedure in the case of parotid and submandibular sialadenitis. In 1998, Bhatty and colleagues stated that superficial parotidectomy was the preferred treatment in selected cases of severe and recurrent chronic parotitis, despite the frequent risk for postoperative facial nerve weakness caused by the frequent adhesion of the facial nerve to glandular tissue. Traditionally, sialadenectomy has been indicated for not only chronic aspecific sialadenitis but also intraparenchymal stones.
Based on this historical background, the traditional management of salivary gland obstruction seems to consist of superficial parotidectomy and traditional transcervical submandibular removal in the case of hilum–parenchymal obstructions; transoral surgical procedures such as sialolithectomy for distal duct stones; and sialodochoplasty for distal duct strictures. Even though sialadenectomy is a relatively standard procedure, it is not devoid of postoperative complications, such as neurologic sequelae which, in the case of parotidectomy, may include transient (2%–76%) or permanent (1%–3%) facial nerve injury; sensory loss of the greater auricular nerve (2%–100%) ; or Frey’s syndrome (8%–33%). In the case of submandibular extirpation, these complications may include temporary (1%–23%) or permanent (1%–8%) marginalis mandibulae nerve injury; temporary (1%–2%) or permanent (3%) hypoglossal nerve palsy; or temporary (2%–6%) or permanent (2%) lingual nerve lesions. Other complications include aesthetic sequelae, such as hematomas (parotid gland, 2%–9%; submandibular gland, 2%–4%) ; salivary fistulas (parotid gland, 2%–18%; submandibular gland, 1%) or sialoceles (parotid gland, 5%–11%; submandibular gland, 1%–3%) ; wound infections (parotid gland, 5%–6%; submandibular gland, 3%–8%) ; hypertrophic scars (parotid gland, 3%–6%; submandibular gland, 2%–5%) ; and inflammation caused by residual stone in the salivary duct (parotid gland, 2–14; submandibular gland, 2%–8%)
Tables 3 and 4 provide detailed descriptions of the frequency of postoperative sequelae after parotid and submandibular gland excision for chronic and obstructive inflammatory disorders of salivary glands.
| Author | No. of Glands Removed | Type of Obstruction | Surgery | Facial Nerve Injury | Greater Auricular Nerve Injury | Greater Auricular Neuroma | Frey’s Syndrome | Hematoma | Wound Infection | Seroma | Fistula | Sialocele | Hypertrophic Keloid | Recurrences |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Casterline and Jaques | 26 | Chronic parotitis, 100% | SP, 35% NTP, 65% | CTP or PTP, 69% | — | — | — | — | — | 4% | — | — | — | 4% |
| Bhatty et al | 17 | SP | PTP, 76% | — | 5% | 15% | — | 5% | — | — | — | — | — | |
| Bates et al | 47 |
|
|
| — | — | — | 4% | — | — | 2% | — | — | 2% |
| Moody et al | 39 | Chronic parotitis, 100% |
|
| 3% | — | 8% | 3% | — | — | 5% | 10% | 5% | 8% |
| Moody et al | 44 |
|
|
| 2% | — | 11% | 2% | — | — | 6% | 11% | 6% | 11% |
| Amin et al | 21 | Chronic parotitis, 100% | SP |
| 100% | 14% | 33% | 5% | 5% | 5% | 5% | 14% | ||
| Patel et al | 78 |
|
|
| — | — | — | 4% | — | 1% | 3% | — | — | 3% |
| Nouraei et al | 34 |
|
|
| — | 3% | 21% | 9% | 6% | — | 18% | — | 3% | — |
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