Complications of Surgery: Recognition and Management

The middle ear and mastoid spaces contain delicate and functionally important structures. Safe cholesteatoma surgery requires mastery of otologic anatomy as well as thorough preoperative investigation. Cholesteatoma can damage otologic structures on its own; however, there is also an opportunity for an iatrogenic complication given the distortion of anatomy by the disease process. This article explores complications that can occur during cholesteatoma surgery, guidance on how to avoid intraoperative complications, and treatment of such complications.

Chorda tympani injury during endoscopic versus microscopic stapes surgery: a randomized controlled clinical trial

OBJECTIVES

The aim of this study was to compare the incidence of chorda tympani nerve (CTN) injury between endoscopic and microscopic stapes surgery.

METHODS

This randomized controlled clinical trial included 88 patients who were randomly divided into two groups: endoscopic stapedotomy group (n = 44) and microscopic stapedotomy group (n = 44). The incidence of chorda tympani nerve (CTN) injury after surgery was determined by both subjective taste testing and chemical taste tests, before and after surgery. The results were compared between the two groups.

RESULTS

The total number of patients who were identified as having CTN affection (based on the chemical testing) was 16 out of 88 (18.2%). The incidence was significantly lower in the endoscopic group (n = 2) than the microscopic group (n = 14) (p = 0.019).

CONCLUSION

Altered taste as a result of iatrogenic CTN injury can affect the patients' quality of life. Endoscopic ear surgery offers better visualization, less need for extensive manipulation of the chorda tympani, and consequently decreased incidence of CTN injury.

Subjective and Objective Taste Change After Stapes Surgery Systematic Review and Meta-Analysis

INTRODUCTION

Iatrogenic injury to the chorda tympani (CT) is a well recognized, although potentially underestimated, consequence of stapes surgery. This study aims to review the currently available literature to determine the incidence and prognosis of taste disturbances in these patients.

DATA SOURCES

PubMed, Embase, and Cochrane Library databases.

METHODS

Databases were searched according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Search terms included (chorda tympani OR gustatory OR taste OR chemosensory OR dysgeusia OR nervus intermedius) AND (ear surgery OR middle ear OR stapes OR stapedectomy OR stapedotomy). Patients with prospective data collection including preoperative data were further divided by methodology into "objective" and "subjective" assessments of taste dysfunction. A systematic review was performed for all included studies, with meta-analysis using a random-effects model was used for those with comparable methodology and patient populations.

RESULTS

Initial search yielded 2,959 articles that were screened according to inclusion and exclusion criteria. Once duplicates were removed, seven studies were identified, representing 173 patients with subjective testing (all seven studies) and 146 with objective testing (five studies). Eighty of 173 patients (46.2%) noted a disturbance in taste at early follow-up, whereas as 26 of 173 (15.0%) noted long-term problems. Objective methodology and result reporting were heterogenous and not amenable to pooled meta-analysis for all studies included.

CONCLUSION

Changes in taste occur relatively frequently after stapedectomy. Surgeons should continue to counsel prospective patients as to the risks of both short- and long-term taste disturbances.

Change in chorda tympani nerve function after two-stage tympanoplasty for cholesteatoma

Objectives

Chorda tympani nerve (CTN) function may be damaged more by two-stage than by one-stage surgery for middle ear cholesteatoma. However, few studies have reported the relationship between two-stage cholesteatoma surgery and CTN function. This study aimed to investigate CTN function after two-stage surgery for cholesteatoma.

Methods

In this prospective study, 35 patients underwent two-stage canal wall up tympanoplasty (CWUT). Perioperative CTN function was assessed using questionnaires and electrogustometry (EGM). Participants were categorized into minor, major, and section groups, based on the degree of CTN manipulation during surgery.

Results

In the first-stage surgery, posterior tympanotomy with an intact canal wall reduced the degree of CTN manipulation. The incidence of taste disorder after the first-stage surgery was 71.4%. Postoperative taste disorder and the EGM threshold improved early in the minor manipulation group. In the second-stage surgery, no new CTN damage occurred, even if this surgery involved removal of residual cholesteatoma. The incidence of taste disorder after second-stage surgery was less than that after first-stage surgery, independent of CTN preservation. However, the recovery rate of the EGM threshold after second-stage surgery was significantly lower in the section group than in those with CTN preservation.

Conclusion

CTN function, including symptoms and EGM threshold, can be preserved during two-stage cholesteatoma surgery if care is taken to preserve the CTN in both the first- and second-stage surgeries. A two-stage CWUT, ensuring an intact bony annulus, may be effective to facilitate CTN preservation.

Level of Evidence

2b.

Recovery of sweet taste preference in adult rats following bilateral chorda tympani nerve transection

Background

Numerous studies have noted the effect of chorda tympani (CT) nerve transection on taste sensitivity yet very few have directly observed its effects on taste receptor and taste signaling protein expressions in the tongue tissue.

Methods

In this study, bilateral CT nerve transection was performed in adult Sprague Dawley rats after establishing behavioral taste preference for sweet, bitter, and salty taste via short term two-bottle preference testing using a lickometer setup. Taste preference for all animals were subsequently monitored. The behavioral testing was paired with tissue sampling and protein expression analysis. Paired groups of CT nerve transected animals (CTX) and sham operated animals (SHAM) were sacrificed 7, 14, and 28 days post operation.

Results

Immunofluorescence staining of extracted tongue tissues shows that CT nerve transection resulted in micro-anatomical changes akin to previous investigations. Among the three taste qualities tested, only the preference for sweet taste was drastically affected. Subsequent results of the short-term two-bottle preference test indicated recovery of sweet taste preference over the course of 28 days. This recovery could possibly be due to maintenance of T1R3, GNAT3, and TRPM5 proteins allowing adaptable recovery of sweet taste preference despite down-regulation of both T1R2 and Sonic hedgehog proteins in CTX animals. This study is the first known attempt to correlate the disruption in taste preference with the altered expression of taste receptors and taste signaling proteins in the tongue brought about by CT nerve transection.

Consequences of Stapes Surgery on Tongue Morphological Characteristics in Narrow Band Imaging, Gustatory Function and General Sensation: A Prospective Tertiary Center Study

(1) Background: Chorda tympani (CT) manipulation during stapes surgery affects its functions. We hypothesized that this alters tongue morphology and sensory functions. (2) Methods: Patients undergoing stapes surgery were tested 1 day preoperatively, 1 and 6 months postoperatively. Narrow band imaging contact endoscopy (NBI) was used to determine the number of fungiform papillae (Npapillae) and the total score of blood vessel morphology (NBItotal). The taste was tested with taste strips. General sensation was tested with a static two-point discrimination. Tests were performed on ipsilateral and contralateral side of the tongue. (3) Results: 52 otosclerosis patients were included in the study. There was a statistically significant decrease of NBItotal (p = 0.005), Npapillae (p = 0.009), sensation of sweet (p = 0.003), salty (p = 0.035), sour (p = 0.036), and bitter taste (p = 0.013) within the test side during the follow-up. A statistically significant impact on presence of dysgeusia for sweet was found 1 month postoperatively (p < 0.005). Postoperative decrease in two-point discrimination score did not reach a statistical significance (p = 0.056). (4) Conclusions: CT manipulation affects fungiform papillae density, vascular patterns and taste sensation. The general sensation of the tongue is not influenced by CT manipulation.

Gustatory Function in Acute COVID ‐19 ‐ Results from Home‐Based Psychophysical Testing

Objective

Gustatory function during COVID‐19 is self‐reported by around 50% of patients. However, only a few studies assessed gustation using psychophysical testing during acute infection. The objective of this study is to test gustatory function on threshold tests in the very first days of COVID‐19.

Methods

Psychophysical testing consisted of validated and blinded tests for olfaction (NHANES Pocket Smell Test) and gustation (Taste Strips Test). These test kits were sent to home‐quarantined patients and self‐administered using a detailed instruction sheet.

Results

A total of 51 patients were included in this study. Testing was performed 6.5 ± 2.7 days after sampling of respiratory swabs. At this time 37% of patients stated to currently experience a gustatory impairment. The mean Taste Strips score was 10.0 ± 3.4 with 28% scoring in the range of hypogeusia. Interestingly, no significant difference in the results of gustatory testing could be observed between the group with subjectively preserved gustation and the group with self‐rated taste impairment.

Conclusion

During the very first days of COVID‐19, psychophysical gustatory testing revealed hypogeusia in 28%. This is far lower than patients' self‐reports. Different from previous studies, we did not find clear evidence for an impairment of only certain taste qualities.

Level of Evidence

3 Laryngoscope, 132:1082–1087, 2022

Endoscopic Anatomy of the Chorda Tympani: Systematic Dissection, Novel Anatomic Classification, and Surgical Implications

HYPOTHESIS

A transcanal endoscopic approach enables visualization of the variable course of the chorda tympani inside the middle ear.

BACKGROUND

The chorda tympani is the longest intrapetrous branch of the facial nerve. Despite having been investigated in several studies, a description of its tympanic tract from an endoscopic point of view is lacking in the literature.

METHODS

We performed transcanal endoscopic dissections of 44 human cadaveric head and ear specimens. The entry point of the chorda tympani into the middle ear was classified into four categories according to its location, and as covered or dehiscent according to its appearance. The chordal eminence (CE) was defined as absent, shallow, intermediate, prominent, or fused, based on its shape and extension. The relationship of the chorda tympani to adjacent bony and ligamental structures was assessed.

RESULTS

The tympanic tract of the chorda tympani was divided into three portions. The periannular segment was dehiscent in 54.5% of specimens, with type II being the most frequent entry point configuration (52.3%). In the interossicular segment, the nerve consistently passed lateral to the incus and medial to the malleus. The course of the intrapetrous segment was independent from the conformation of the tensor fold and supratubal recess.

CONCLUSION

The transcanal endoscopic approach allows a detailed description of tympanic segment of the chorda tympani. Novel anatomic classifications of the chorda tympani and CE are proposed herein to highlight their possible surgical implications during otologic procedures.

Flavor Enhancement in Daily Life of Patients with Olfactory Dysfunction

Introduction

Patients with olfactory dysfunction report deterioration of taste due to loss of flavor, leading to less food enjoyment, alterations in dietary behaviors and stress. The aim of this study was to introduce flavor enhancement to investigate its acceptance and possible effects on quality of life.

Methods

In this prospective, controlled, randomized, single-blinded, cross-over pilot study, we recruited 30 olfactory dysfunction patients, of which 16 were hyposmic and 14 anosmic. After single-blinded triangle flavor discrimination test, flavor drops were randomized either in high or low concentration for 14 days and vice versa for another 14 days. Records included a daily diary and the questionnaire of olfactory disorders.

Results

Usage rates were excellent with 82.2% of all days, while drops were mainly used for breakfast (44.6%, p < 0.05). Hyposmics used flavor enhancement on significantly more days (median = 14) compared to anosmics (median = 11, p = 0.0094). QOD improved in 12 patients to a meaningful extent.

Conclusions

In this pilot study, we show that flavor enhancement is feasible accompanied by high compliance and acceptance in olfactory dysfunction patients. Flavor drops were used regardless of low or high concentrations with no adverse events noted.

Implications

Our findings give rise to further studies illuminating the possible advantages of flavor enhancement in patients with olfactory disorders.

Taste impairment after endoscopic stapes surgery: Do anatomic variability of chorda tympani and surgical technique matter? : Post-operative dysgeusia after EStS

PURPOSE

To investigate how the anatomical configuration of the oval window region (OWR) influences the management of the chorda tympani (ChT) and the curetting of adjacent bony structures, in a setting of patients undergoing endoscopic stapes surgery (EStS); to assess the incidence of early and late post-operative dysgeusia and to identify anatomical and surgical factors influencing taste function after EStS.

METHODS

Surgical video recordings of 48 patients undergoing EStS for otosclerosis between January 2019 and July 2020 were retrospectively revised, to classify the anatomical variability of selected middle ear structures and the management strategies for the ChT. Clinical records of included patients were reviewed for subjective early and late post-operative taste impairment using a 5-point Likert-scale.

RESULTS

The most common configuration of the OWR was type III. The extension of the bony curettage resulted inversely proportional to the exposure of the OWR. The long-term rate of preserved post-operative taste function was 85%. Displacement of the ChT was necessary in 43/48 cases (90%), mostly medially (36/48, 75%).

CONCLUSION

Bone curetting during EStS does not correlate with post-operative taste impairment. Despite 100% ChT preservation rate, dysgeusia may occur in a minority of patients, with no apparent relationship to anatomical variability or intraoperative management of the ChT. The use of CO₂ laser could have a role in increasing the risk of post-operative dysgeusia after EStS.

Taste-strip gustometry in cochlear implanted patients

OBJECTIVE

Investigation of the gustatory function in a large cohort of cochlear implanted patients using lateralized taste-strip tests.

PATIENTS AND METHODS

One hundred and seven unilaterally or bilaterally profoundly hearing impaired or deaf patients who received cochlear implants (n = 113) were included in this study. Data on gustometry, subjective gustatory dysfunction, and the detailed surgical procedure were acquired retrospectively. Gustatory function, assessed using lateralized taste-strip tests, was performed the day before, 3 days after cochlear implantation, and on the day of the initial CI adjustment (39 days ±7.3 SD).

RESULTS

Averaged taste-strip scores of the cohort declined significantly from preoperatively 12.3 [11.8; 12.7] (mean [95% confidence intervals]) to 10.5 [9.7; 11.2] on the implanted side about 6 weeks after surgery. Patients with intraoperatively exposed and rerouted, or a severed, chorda tympani nerve (CTN) showed significantly reduced unilateral postoperative scores (10.1 [8.8; 11.4] and 9.3 [8.1; 10.5], respectively), when compared to not exposing or to leaving a bony layer over the CTN. Total taste-strip test scores showed a significant decline 6 weeks postoperatively in CI-patients expressing a subjective gustatory dysfunction (from 23.6 [21.4; 25.8] to 17.5 [14.2; 20.8]), as opposed to patients with a documented subjectively normal taste.

CONCLUSION

We consider postoperative gustatory dysfunction as a relevant side effect post cochlear implantation, at least within the first month. Taste-strip based gustometry is a suitable diagnostic tool to assess taste function in CI patients and is recommended to be performed routinely.

LEVEL OF EVIDENCE

3, retrospective, nonrandomized follow-up study.

Chemical, Electrical and Tactile Sensitivity Changes After Middle Ear Surgery

OBJECTIVE/HYPOTHESIS

Taste disturbances are often seen in patients after middle ear surgery due to the stress received by an unprotected chorda tympani. It has also been reported that loss in tactile sensitivity may accompany this issue. The current study was designed to measure electrical, chemical, and tactile sensitives of several senses involved in oral processing, smell, taste and touch, over time.

STUDY DESIGN

Prospective cohort study.

METHODS

For three time points, one before middle ear surgery and two after operation (about 5 and 23 days), sensitivity thresholds were obtained using electrogustometry (electrical taste), taste strips (chemical taste), Sniffin' Sticks (smell) and Von Frey Hairs (point-pressure tactile sensitivity).

RESULTS

The results show a decline in both chemical and electrical taste responses. Additionally, the electrical taste response showed more sensitivity to deviations and no sign of recovery unlike the chemical taste response. Mechanosensory function of the anterior tongue and olfactory function was not strongly affected by middle ear surgery.

CONCLUSION

Taste responses, but not mechanosensory or olfaction function, are altered after middle ear surgery. Due to the effects that taste loss has on quality of life, gustometry is recommended for this group of patients.

LEVELS OF EVIDENCE

4.

Taste Changes in Patients With Middle Ear Surgery by Intraoperative Manipulation of Chorda Tympani Nerve

OBJECTIVES

The aim of study was to evaluate the subjective changes of taste and salivation after middle ear surgery according to chorda tympani nerve (CTN) injury.

STUDY DESIGN

Prospective cohort study.

SETTING

Tertiary referral center.

PATIENTS

We enrolled 180 patients older than 13 years old who received middle ear surgery.

INTERVENTIONS

The patients were classified into cut, manipulated, and intact groups according to intraoperative assessments of the CTN. The patients responded taste and salivation surveys preoperatively, and 1, 3, and 6 months postoperatively.

MAIN OUTCOME MEASURES

We analyzed results of questionnaires including disturbance rates, severity and character to evaluate taste and salivation functions.

RESULTS

Taste disturbance rate was significantly improved in all groups during follow-up (p < 0.05). The incidence of taste disturbance did not differ significantly between the three groups at each follow-up (p > 0.05). The taste disturbance score improved gradually in the cut and intact groups (p < 0.001), but not in the manipulated group (p = 0.067). Among the patients with taste disturbance, hypoguesia was most common symptom. Incidence of salivation disturbance did not differ between the three groups (p = 0.298). However, this symptom improved significantly only in the intact group (p < 0.001). The taste and salivation disturbance rate was not different between patients with and without chronic otitis media at 3 and 6 months, and both groups showed significant improvement.

CONCLUSIONS

Prevalence of taste and salivation disturbance was similar between three groups until 6 months. However, taste disturbance did not improve in the manipulated group and salivation disturbance improved only in the intact group.

Feasibility of preservation of chorda tympani nerve during noninflammatory ear surgery: A systematic review

OBJECTIVE

The objective of our systematic review is to investigate the postoperative gustatory function of the chorda tympani nerve following noninflammatory ear surgery for which the chorda tympani is at risk for iatrogenic injury (stretching, handling, or sacrificing).

DATA SOURCES

PubMed and EMBASE.

REVIEW METHODS

A PubMed and EMBASE databases search was conducted on November 15, 2016. Study inclusion criteria included: 1) ear surgery performed for noninflammatory ear diseases, and 2) gustatory function of the chorda tympani reported as an outcome. The quality of eligible studies was assessed using the risk of bias assessment tool for nonrandomized studies. Study characteristics and outcome data of the included studies were extracted.

RESULTS

In total 1,094 articles were retrieved. Fourteen studies encompassing 1,062 operated ears were included after quality assessment. Stapedectomy was the most frequent surgical procedure performed in 398 ears. The follow-up time varied between 6 weeks and 99 months. Patients with a preserved chorda tympani were less symptomatic (24% was symptomatic) compared to patients with a stretched (53% was symptomatic) or sacrificed chorda tympani (47% was symptomatic). The recovery rate varied from 61% to 79%. The results of the electrogustometry and strip test showed a discrepancy with the subjective complaints of the patients.

CONCLUSION

Patients with a stretched chorda tympani were slightly more symptomatic compared to patients with a sacrificed chorda tympani. Therefore, in cases for which the chorda tympani greatly hinders a proper view of the surgical field, sacrificing the nerve could be considered to maximize surgical performance and have a satisfactory postoperative result. Laryngoscope, 1904-1913, 2018.

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.

Case Report: Diagnosis of hypogeusia after oral exposure to commercial cleaning agent and considerations for clinical taste testing

Few reports in the literature document acute taste disturbance following exposure to toxic chemicals. We describe the case of a 54-year-old man who presented with primary complaint of tongue numbness and persistent problems with taste 1.5 years following oral exposure to a commercial cleaning agent. A test of olfaction revealed normosmia for age and gender. Lingual tactile two-point discrimination testing showed reduced somatosensation. Taste threshold testing using a 3-drop method demonstrated severe hypogeusia, though the patient was able to discriminate tastants at lower concentrations with a whole mouth swish and spit test. We conclude that clinical evaluation of dysgeusia can be performed using a number of previously published testing methods, however, determining causative factors may be confounded by duration since exposure, lack of knowledge of baseline taste function, and medications. Although many testing options exist, basic taste testing can be performed with minimal expertise or specialized equipment, depending on the patient history and goals of evaluation.

Taste disturbance after stapes surgery: an evaluation of frequency, severity, duration, and quality-of-life

CONCLUSION

The incidence of taste disturbance after stapes surgery is high (61.9%), whereas the majority (94.8%) recovers within 1 year. More severe surgical nerve trauma caused more disturbance, implying that the nerve should be handled carefully during surgery.

OBJECTIVES

Patients operated on for otosclerosis seem more often to complain about post-operative taste disturbance than those operated on for chronic otitis media, although the chorda tympani nerve more seldom becomes maltreated in stapedotomy. These observations seem paradoxical. It is unclear to what extent a post-operative taste disturbance affects the quality-of-life. This study aims to shed light on the occurrence of post-operative taste disturbances, on possible prognostic factors, and to what extent post-operative taste disturbance impairs the quality-of-life.

METHODS

One hundred and thirty-four adults undergoing primary stapedotomy were included. Questionnaires on taste disturbance and quality-of-life (SF-36) were answered before and after surgery, until 1 year post-operatively.

RESULTS

Eighty-three (61.9%) study persons reported post-operative taste disturbance. Seven (5.2%) reported persisting disturbance at 1 year. Surgically more traumatized chorda tympani nerves correlated with more severe taste disturbance post-operatively than less traumatized. Taste disturbance at 1 year post-operatively correlate with a decrease of the physical function domain in the SF-36.

Gustatory function in chronic otitis media (mucosal type) before and after tympanoplasty

Chronic inflammation in the middle ear may result in functional impairment of the chorda tympani nerve, which carries taste from the anterior two-thirds of the tongue. This may lead to impaired taste sensation. Timely intervention and adequate disease clearance may help the chorda tympani nerve to recover. Gustatory function of 107 patients who underwent Tympanoplasty for Chronic otitis media (mucosal type) was evaluated in a cohort of Indian patients. To compare the preoperative and postoperative gustatory function in these patients taste scores were documented preoperatively, and at 6 weeks and 3 months postoperatively, in an effort to document taste function improvement after disease clearance. The taste scores thus obtained were recorded and analyzed. A significant improvement in taste threshold postoperatively in comparison to the preoperative taste scores (p = 0.001) was found. It was observed that age of the patient and duration of illness have a significant impact on the recovery of taste function. Our study suggests that taste perception improves over a period of time after successful tympanoplasty in patients with chronic otitis media (mucosal type).

A self-administered test of taste function using "Taste Strips"

BACKGROUND

Assessment of gustatory function with impregnated taste strips is an established and validated method. In clinical routine, application of the tests is often limited due to lack of time or costs associated with administering the test. The aim of the study was to develop a procedure suitable for self-administration of the "Taste Strips" test.

METHODS

The investigated participants (n = 65; 22 males, 43 females; mean age 36.7 ± 19.2 years; range, 20 to 83 years) were tested twice in a randomized crossover procedure. On 1 occasion, an examiner administered the established and validated "Taste Strips" test. On another occasion, test subjects administered the taste strips themselves. Results of both test methods were compared.

RESULTS

The mean score (± standard deviation [SD]) of the assisted taste test (11.6 ± 2.6) was significantly lower compared to the mean self-administered taste test that yielded 12.3 ± 2.6 points (Wilcoxon test: z = 2.836; p < 0.01). Comparison of mean values showed minimal difference of the tested procedures of 0.7 ± 1.9 points with a significant positive correlation of test results (r65 = 0.734; p < 0.01).

CONCLUSION

Although a small difference between test results was observed, the new test procedure seems to be an adequate screening tool for assessment of taste function with less personnel effort, leading to improved management of patients with chemosensory disorders.

Taste and olfaction in middle ear surgery

OBJECTIVE

The aim of this study was to assess pre- and postoperative taste ability in patients undergoing middle ear surgery for otosclerosis or chronic otitis media. Olfactory function was also evaluated to rule out taste deficits due to concomitant nasal pathology.

METHODS

All patients underwent ear, nose, and throat examination, otomicroscopy, nasal endoscopy, anterior rhinomanometry, taste testing, and olfactory testing. Patients were evaluated at 1 to 5 days preoperatively (T0), and at 1 (T1), 6 (T6), and 12 (T12) months postoperatively.

RESULTS

Both groups of patients experienced worsening of the mean taste threshold postoperatively. This phenomenon was more serious in poststapedotomy patients. Follow-up showed progressive improvement in both groups. All values of olfactory testing were within the normal range for otosclerosis patients. Patients with chronic otitis media showed variable postoperative findings.

CONCLUSION

Chorda tympani function can be negatively affected by middle ear surgery. Deficits may be more marked in stapedotomy patients than in those undergoing tympanoplasty. Postoperative recovery of taste is satisfactory, although with different timelines for the 2 types of pathology.

Iatrogenic injury of the chorda tympani: a systematic review

Objective:

To review the currently available literature on iatrogenic injury of the adult chorda tympani.

Design:

Systematic literature review.

Method

Five electronic databases and one search engine were used to access available English language literature on the chorda tympani, focusing on iatrogenic injury.

Results:

The chorda tympani is most often injured during middle-ear surgery, after which at least 15–22 per cent of patients experience symptoms, mostly changes in taste and dryness of the mouth. Numerous factors influence whether injury to the chorda tympani causes symptoms, including the extent of injury, type of surgery, age of the patient, anatomical variables and subjective adaptation. Although most patients experience gradual symptomatic recovery, complaints can be persistent and troublesome.

Conclusion:

Care should be taken to preserve the chorda tympani during middle-ear surgery, and to warn patients pre-operatively about this potential complication. This is particularly important if surgery is bilateral.

Cutting the chorda tympani: not just a matter of taste

Introduction:

Chorda tympani injury as a complication of middle-ear surgery has been extensively studied with regard to its effects upon taste. However, the chorda tympani also carries parasympathetic fibres to the salivary glands of the oral cavity. To date, little has been reported about the effect of chorda tympani section upon salivary function.

Setting:

Tertiary care centre.

Material and methods:

We report a case series of three patients with bilateral chorda tympani lesions. Chorda tympani function was assessed using ‘taste strips’ and unstimulated sialometry. A careful history of oral symptoms was taken.

Results:

All patients showed transient or permanent bilateral ageusia of the anterior two-thirds of the tongue, and a decreased resting salivary flow rate. In addition, all patients suffered from transient or persistent, distressing xerostomia.

Conclusion:

Taste disorders may occur after middle-ear surgery but they are mostly transient, even when the chorda tympani nerves are sectioned bilaterally. In contrast, bilateral chorda tympani lesions may lead to severe, persistent and distressing xerostomia. Based on this neglected aspect of chorda tympani function, we emphasise the importance of preserving the chorda tympani whenever possible.