Botulinum Toxin-Induced Parotitis: A Postoperative Complication Following Masseter Muscle Injection

Botulinum toxin (BTX) injection is a common treatment for bruxism, but there is no literature on potential salivary gland complications. This paper presents a case of acute parotitis in a 60-year-old female following BTX injections to the masseter muscle. This case highlights the possible salivary gland complications after injection of BTX into the masticatory muscles. An electronic search of PubMed and Embase databases was conducted to create a literature review in order to delve into the etiology behind the presented case and suggest potential preventive measures to avoid salivary gland complications. Thirty-one articles are reviewed and discussed. Currently, there is no consensus on the causes of the mentioned complication. However, various factors have been proposed, encompassing anatomical, physiological, biological, and physical aspects. Several methods have been recommended for the safe injection of BTX, which, along with better medical training and knowledge, are warranted to achieve predictable results.

Botulinum toxin for chronic parotid sialadenitis: A case series and systematic review

OBJECTIVE

To evaluate salivary gland chemodenervation with botulinum toxin in chronic parotid sialadenitis.

METHODS

Patients who underwent parotid gland chemodenervation for chronic sialadenitis due to duct stenosis refractory to siaendoscopy were reviewed (case series). Additionally, a systematic review of the literature on botulinum toxin injection for chronic parotid sialadenitis was performed. Inclusion criteria included studies containing original data on botulinum toxin injections in patients with chronic sialadenitis symptoms.

RESULTS

Sialadenitis symptoms from 10 patients with 13 affected parotid glands were examined. All had duct stenosis diagnosed on sialendoscopy, refractory sialadenitis symptoms, and received parotid onabotulinum toxin injection(s) (median dose 65U). Of patients with 3-month follow-up, 78% reported significant improvement in symptoms. Mean Chronic Obstructive Sialadenitis Symptoms (COSS) Score improved at 3 months post-injection (47-25.9, P = .039) with significant reduction in gland pain frequency and gland swelling severity. No patients had a facial nerve paralysis or increased xerostomia. With the systematic review, 518 abstracts were reviewed and 11 studies met inclusion criteria and included case series or case reports with a total of 40 patients treated with botulinum toxin for chronic parotitis. Thirty-four out of a total of 35 patients in the studies (97%) reported complete (9, 26%) or partial (25, 71%) improvement in sialadenitis symptoms with minimal complications.

CONCLUSION

Parotid gland chemodenervation with botulinum toxin is a minimally invasive treatment option for symptomatic chronic sialadenitis refractory to medical treatment or sialendoscopy. Botulinum toxin injections alleviate gland pain and swelling associated with salivary obstruction and provide an alternative to parotidectomy for recurrent sialadenitis.Level of evidence: 4.

Botulinum Toxin Injection for Chronic Parotitis: A Multi-Center and Prospective Trial

OBJECTIVE

When conservative therapy fails for chronic parotitis, sialendoscopic treatment or surgical excision can be considered. However, these are financially costly or invasive. Thus, this study aimed to evaluate the clinical efficacy and safety of botulinum toxin (BTX) injection and to further analyze its effect on parotid gland function and volume using salivary single-photon emission computed tomography (SPECT)-computed tomography (CT).

METHODS

This clinical trial has been registered in the Clinical Research Information Service, Republic of Korea. Fourteen patients with chronic parotitis received BTX injections into the parotid glands. Pain, postprandial pain, swelling, aesthetic discomfort, and salivary flow rate were assessed before injection, at 2 weeks, and at 1, 3, and 6 months. Salivary SPECT-CT was performed before injection and again 3 and 6 months after to assess the volume and uptake changes.

RESULTS

All subjective symptoms decreased significantly until 1 month and then increased. However, at 6 months, all subjective symptoms were determined to be better than before injection. The unstimulated and stimulated salivary flow rate did not show a significant difference over time. No significant difference was noted in parotid gland volume or uptake on salivary SPECT-CT over time.

CONCLUSION

BTX injection can be an alternative treatment option for chronic parotitis.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E1903-E1909, 2021.

Salivary duct stenosis: diagnosis and treatment

The management of stenoses of the major salivary glands had undergone a significant change during the last 15-20 years. Accurate diagnosis forms the basis of adapted minimal invasive therapy. Conventional sialography and MR-sialography are useful examination tools, and ultrasound seems to be a first-line investigational tool if salivary duct stenosis is suspected as cause of gland obstruction. Sialendoscopy is the best choice to establish final diagnosis and characterise the stenosis in order to plan accurate treatment. In all major salivary glands, inflammatory stenosis can be distinguished from fibrotic stenosis. In the parotid duct system, an additional stenosis associated with various abnormalities of the duct system has been reported. Conservative therapy is not sufficient in the majority of cases. The development of a minimally invasive treatment regime, in which sialendoscopy plays a major role, has made the preservation of the gland and its function possible in over 90% of cases. Ductal incision procedures are the most important measure in submandibular duct stenoses, but sialendoscopy becomes more important in the more centrally located stenoses. Sialendoscopic controlled opening and dilation is the dominating method in parotid duct stenoses. In 10-15% of cases, success can be achieved after a combined treatment regime had been applied. This review article aims to give an overview on the epidemiology, diagnostics and current state of the art of the treatment of salivary duct stenoses.

Botulinum toxin therapy: functional silencing of salivary disorders

Botulinum toxin (BTX) is a neurotoxic protein produced by Clostridium botulinum, an anaerobic bacterium. BTX therapy is a safe and effective treatment when used for functional silencing of the salivary glands in disorders such as sialoceles and salivary fistulae that may have a post-traumatic or post-operative origin. BTX injections can be considered in sialoceles and salivary fistulae after the failure of or together with conservative treatments (e.g. antibiotics, pressure dressings, or serial aspirations). BTX treatment has a promising role in chronic sialadenitis. BTX therapy is highly successful in the treatment of gustatory sweating (Frey's syndrome), and could be considered the gold standard treatment for this neurological disorder.