Oral Neuropathy Associated with Commonly used Chemotherapeutic Agents: A Narrative Review.

PURPOSE OF REVIEW: Chemotherapy-induced peripheral neuropathy (CIPN) is a frequent complication of cytotoxic chemotherapeutic agents; its incidence largely varies, depending on type, dose, agent and preexisting risk factors. Oral-and-perioral-CIPN (OCIPN) is underreported. Neurotoxic agents can cause jaw pain or numbness. This review aims to present available data on OCIPN RECENT FINDINGS: A narrative literature review, following SANRA guidelines was conducted. PubMed and Cochrane databases were searched until September 2023. Articles referring to neuropathy or neuropathic pain due to head and neck cancer, head and neck radiotherapy, oropharyngeal mucositis, infection or post-surgical pain were excluded. Platinum-based chemotherapeutics, taxanes, vinca alkaloids, immunomodulatory and alkylating agents can cause OCIPN. Platinum-based chemotherapeutics can cause orofacial cold sensitivity, orofacial and jaw pain, oral cavity tingling and teeth hypersensitivity. Taxanes may induce oral cavity and tongue numbness and tingling as well as hot hypersensitivity. Vinca alkaloids may cause jaw, teeth and lips pain and oral mucosa hyperalgesia. Immunomodulatory drugs can cause lips, tongue and perioral numbness, while alkylating agents induce tongue and lips tingling and teeth cold-hypersensitivity. Chemotherapy may cause OCIPN due to changes in cellular structure and function, like alterations in membrane receptors and neurotransmission. OCIPN should be documented and physicians, dentists and health care providers should be alerted.

Does early repair of trigeminal nerve injuries influence neurosensory recovery? A systematic review and meta-analysis.

This systematic review and exploratory meta-analysis of the available evidence was performed to examine whether early nerve repair of lingual nerve (LN) and inferior alveolar nerve (IAN) injuries has an effect on neurosensory recovery. A literature search was conducted to identify relevant studies meeting the inclusion criteria. Two reviewers independently evaluated the methodological quality of the included studies and the risk of bias using the ROBINS-I quality assessment tool. For the quantitative analysis, data were pooled using the Mantel-Haenszel random-effects method due to the clinical heterogeneity across the studies. Sensitivity and subgroup analyses were performed based upon the group definition of timing from injury to nerve repair, with breakpoints of 2, 3, and 6 months. A total 1236 citations were identified, with a final 13 studies included in the systematic review. A clear definition of 'early' versus 'late' repair was not reported in six studies, allowing only seven to be included in the meta-analysis. The effect of early repair on functional sensory recovery was found not to be significant in nine studies, while four studies found a significant effect of early intervention. The meta-analysis showed a combined success rate of 93.0% for the early group and 78.5% for the late group. The odds of improvement were 5.49 (95% confidence interval 1.40-21.45) in the 3-month breakpoint studies and 2.28 (95% confidence interval 1.05-4.98) in the 6-month studies. A trend towards early repair achieving better functional sensory recovery outcomes was observed, but the specific time period is unknown.

Earlier recovery of lingual dysfunction after middle ear surgery in pediatric versus adult patients.

OBJECTIVES: It is generally thought that the recovery of damaged chorda tympani nerve (CTN) function after middle ear surgery is different in pediatric patients from that in adult patients. The purpose of this study was to investigate the changes and the progress of taste and somatosensory functions of the tongue after middle ear surgery in pediatric patients compared with those of adult patients. STUDY DESIGN: Prospective study. METHODS: Fifty-nine pediatric patients and 106 adult patients underwent middle ear surgery. Taste and somatosensory functions of the anterior tongue, the so-called CTN functions, were assessed using electrogustometry (EGM), a 2-point discriminator, an electrostimulator, and a questionnaire before and 2 weeks and 6 months after surgery. RESULTS: Two weeks after surgery, there was no significant difference in the incidence of dysgeusia and abnormal EGM thresholds between the patient groups. The incidence of tongue numbness was significantly lower in pediatric patients than in adult patients regardless of CTN manipulation. Although the lingual somatosensory thresholds of adult patients were significantly increased, those of pediatric patients were not increased. Six months after surgery, the incidences of dysgeusia and an abnormal EGM threshold were lower in pediatric patients than in adult patients. Tongue numbness disappeared, and the thresholds of lingual somatosensory tests returned to normal in most pediatric patients. CONCLUSION: Not only taste function but also lingual somatosensory function was damaged after middle ear surgery even in pediatric patients. Pediatric patients complained of tongue numbness less frequently and showed earlier recovery than adult patients. LEVEL OF EVIDENCE: 2 Laryngoscope, 130:1016-1022, 2020.

Change of somatosensory function of the tongue caused by chorda tympani nerve disorder after stapes surgery.

OBJECTIVES: Patients after middle ear surgery often complain of taste disturbance and a lingual numbness. The purpose of this study was to objectively assess changes in the somatosensation of the tongue and taste function in patients undergoing stapes surgery. STUDY DESIGN: Prospective study. METHODS: Symptoms of taste disturbance and tongue numbness after surgery were investigated before and after surgery in 41 patients (13 males, 28 females; mean age 41.8 years) who underwent stapes surgery. Twenty-eight patients (9 males, 19 females; mean age 43.1 years) underwent sensory and taste function tests before and after surgery. Sensory function of the tongue was measured at the operated side and the nonoperated side using the 2-point discrimination test and an electrostimulator test. Taste function was assessed with electrogustometry (EGM). RESULTS: The chorda tympani nerve (CTN) was gently touched or stretched in all patients. Postoperative thresholds on the operated side were significantly higher than preoperative thresholds in all tests in the patients who underwent all three kinds of tests. Tongue somatosensory symptoms improved significantly earlier than the taste disturbance postoperatively, and the sensory thresholds returned to the baseline along with recovery of symptoms. CONCLUSION: These findings suggest that dysfunction of the CTN occurred following surgery even when the CTN was preserved, and that the sensory nerve threshold of the tongue correlated with the symptom of lingual numbness. The CTN may play a role not only in taste function but also in the somatosensory function of the tongue. LEVEL OF EVIDENCE: 4. Laryngoscope, 128:701-706, 2018.