Tullio phenomenon and postural stability: experimental study in normal subjects and patients with vertigo

Comparison of the effect of sevoflurane and propofol on the optic nerve sheath diameter in patients undergoing middle ear surgery

PURPOSE

During middle ear surgery, the patient's head is turned away from the surgical site, which may increase the intracranial pressure. Anesthetics also affect the intracranial pressure. The optic nerve sheath diameter (ONSD) measured using ultrasonography is a reliable marker for estimating the intracranial pressure. This aim of this study was to investigate the effect of sevoflurane and propofol on the ONSD in patients undergoing middle ear surgery.

METHODS

Fifty-eight adult patients were randomized into sevoflurane group (n = 29) or propofol group (n = 29). The ONSD was measured using ultrasound after anesthesia induction before head rotation (T0), and at the end of surgery (T1). The occurrence and severity of postoperative nausea and vomiting (PONV) were assessed 1 h after the surgery.

RESULTS

The ONSD was significantly increased from T0 to T1 in the sevoflurane group [4.3 (0.5) mm vs. 4.9 (0.6) mm, respectively; P < 0.001] and the propofol group [4.2 (0.3) mm vs. 4.8 (0.5) mm, respectively; P < 0.001]. No significant difference was observed in the ONSD at T0 (P = 0.267) and T1 (P = 0.384) between the two groups. The change in the ONSD from T0 to T1 was not significantly different between the sevoflurane and propofol groups [0.6 (0.4) mm vs. 0.6 (0.3) mm, respectively; P = 0.972]. The occurrence and severity of PONV was not significantly different between the sevoflurane and propofol groups (18% vs. 0%, respectively; P = 0.053).

CONCLUSION

The ONSD was significantly increased during middle ear surgery. No significant difference was observed in the amount of ONSD increase between the sevoflurane and propofol groups.

Vestibular Hypersensitivity in Patients with Chronic Noise Exposure

It has been demonstrated that high-intensity noise exposure adversely affects the human balance function. The Tullio phenomenon (TP) refers to sound-induced imbalance which is resulted from hypersensitivity of vestibular end organs to normal acoustic stimuli. Although different etiologies have been attributed to TP, evidence on the role of excessive noise exposure in the development of this symptom is limited. The present study aims to assess the vestibular functions in patients manifesting TP symptom who were exposed to long-term excessive noise levels. This was an analytic cross-sectional study conducted on 17 males diagnosed with TP with a history of chronic noise-induced hearing loss (TP group) and 17 healthy individuals. All subjects in both groups underwent complete otological, videonystagmography (VNG), and cervical vestibular myogenic potential (cVEMP) assessments. The most common complaint in TP subjects was vertigo and imbalance. During the VNG assessment, we found abnormal positional nystagmus and caloric irrigation (vestibular hyperfunction) results in 4 (23.53%) and 9 (52.94%) patients, respectively. Seven (41.17%) patients indicated cVEMP thresholds which were abnormally lower than the normal values ( ≤ 70 dB HL). However, when both VNG and cVEMP results were considered together, the abnormal rate reached 70.58% (12 of 17 cases). Our findings showed that both the semicircular canal as well as otolith stuctures could be affected in TP patients with a history of chronic noise exposure.

Biomechanics of Third Window Syndrome

Third window syndrome describes a set of vestibular and auditory symptoms that arise when a pathological third mobile window is present in the bony labyrinth of the inner ear. The pathological mobile window (or windows) adds to the oval and round windows, disrupting normal auditory and vestibular function by altering biomechanics of the inner ear. The most commonly occurring third window syndrome arises from superior semicircular canal dehiscence (SSCD), where a section of bone overlying the superior semicircular canal is absent or thinned (near-dehiscence). The presentation of SSCD syndrome is well characterized by clinical audiological and vestibular tests. In this review, we describe how the third compliant window introduced by a SSCD alters the biomechanics of the inner ear and thereby leads to vestibular and auditory symptoms. Understanding the biomechanical origins of SSCD further provides insight into other third window syndromes and the potential of restoring function or reducing symptoms through surgical repair.

Transient Vertigo with Horizontal Nystagmus to Loud Noise and Pressure: Utricular Hydrops or Vestibular Atelectasis?

We present an unusual case of a patient with a positive Tullio phenomenon, brief Valsalva-induced transient horizontal nystagmus, reduced left caloric response, and bilateral vestibulo-ocular reflex loss. This study discusses the pathophysiology and differential diagnosis concerning the suspected pathology for the phenomenon of utricular hydrops or vestibular atelectasis and presents a literature review.

Betahistine as an add-on: The magic bullet for postoperative nausea, vomiting and dizziness after middle ear surgery?

PURPOSE

Patients undergoing middle ear surgery experience variable degrees of postoperative nausea and vomiting (PONV) despite prophylaxis and treatment with ondansetron or other 5HT3 receptor antagonists. Furthermore vertigo or dizziness are not well controlled perioperatively. Role of betahistine was tested as an add-on to ondansetron in control of PONV and vertigo in middle ear surgery cases.

MATERIALS AND METHODS

We conducted a prospective, randomized, double-blind, placebo controlled study, enrolling one hundred patients undergoing middle ear surgery under local anesthesia into two groups consisting of fifty (n = 50) patients each. Group A patients were given betahistine 16 mg plus ondansetron 8 mg and placebo plus ondansetron 8 mg were given to group B or placebo group, orally 3 hours before starting operation. The incidence of nausea, vomiting, and dizziness was noted during the intraoperative and postoperative 24 hours period. Chi-square test, unpaired 't' test, and Fisher's exact tests were performed for statistical analysis using SPSS version 16 and Open Epi version 2.3.1 softwares.

RESULTS

Complete response was obtained in 90% patients in the betahistine group as compared to 66% in the placebo group. Vomiting in the intraoperative and postoperative period was noted in 4% and 8% cases, respectively, in the betahistine group as compared to 18% and 26%, respectively, in the placebo group. Overall, vertigo was 10% versus 32% in betahistine group and placebo group, respectively.

CONCLUSION

Betahistine as an add-on to ondansetron can significantly attenuate PONV and perioperative vertigo, following middle ear surgeries.

Postoperative nausea and vomiting after myringoplasty under continuous sedation using midazolam with or without remifentanil

PURPOSE

This prospective study evaluated the effects of continuous sedation using midazolam, with or without remifentanil, on postoperative nausea and vomiting (PONV) in patients undergoing myringoplasty.

MATERIALS AND METHODS

Sixty patients undergoing myringoplasty were sedated with midazolam in the presence of remifentanil (group MR), or after saline injection instead of remifentanil (group M).

RESULTS

Three patients (10%) in group M complained of nausea; two vomited. Four patients (13%) in group MR complained of nausea and vomited within 24 h after surgery. Rescue drugs were given to the six patients who vomited. No significant difference was detected between the two groups regarding the incidence or severity of nausea, incidence of vomiting, or need for rescue drugs.

CONCLUSION

Midazolam-based continuous sedation can reduce PONV after myringoplasty. Compared with midazolam alone, midazolam with remifentanil produced no difference in the incidence or severity of nausea, incidence of vomiting, or need for rescue drugs.

Randomized double blind comparative study comparing efficacy of granisetron and ondansetron for the prophylactic control of postoperative nausea and vomiting in patients undergoing middle ear surgery

The objective is to evaluate the prophylactic profile, efficacy of granisetron and ondansetron to prevent postoperative nausea and vomiting (PONV) after middle ear surgery. In a randomized, double blind trial, one hundred patients undergoing middle ear surgery received either granisetron 1 mg or ondansetron 8 mg in equal volume (n = 50 for each) intravenously towards the end of surgery and before reversal of anaesthesia. A standard general anaesthetic technique was employed. Postoperatively, during the first 24 h after anaesthesia, the incidence of PONV, recovery score, time to first feeding, willingness to have the same prophylactic antiemetic drug in future and adverse events were recorded. The incidence of vomiting once (PONV score 2) was significantly less, 4% with granisetron and 22% with ondansetron (P = 0.002) respectively and the incidence of vomiting twice or more times in 30 min interval (PONV score 3) was significantly less, 8% with granisetron as compared to 34% with ondansetron (P = 0.001). The requirement of rescue antiemetic drug was significantly higher in ondansetron group, i.e. 34 vs. 8% in granisetron group (P = 0.001). The incidence of adverse events, recovery score and time to first feeding were comparable among the groups. Willingness to have the same prophylactic antiemetic drug in future was significantly high in patients receiving granisetron. Granisetron is more efficacious and desirable drug than ondansetron for reducing the incidence of PONV in patients undergoing middle ear surgery.

Effect of i.v. dexamethasone on postoperative dizziness, nausea and pain during canal wall-up mastoidectomy

CONCLUSION

Prophylactic i.v. administration of 10 mg of dexamethasone reduced postoperative dizziness and nausea without adverse effects in patients undergoing canal wall-up mastoidectomy, but did not reduce postoperative pain.

OBJECTIVE

To investigate the efficacy of dexamethasone in reducing postoperative dizziness, nausea and pain in patients undergoing canal wall-up mastoidectomy.

MATERIAL AND METHODS

A prospective, randomized, double-blind study was performed between January 2002 and December 2004. A total of 162 patients (66 males, 96 females) scheduled for canal wall-up mastoidectomy were enrolled and randomly assigned to receive either i.v. dexamethasone (10 mg in 2 ml) or i.v. placebo (2 ml of normal saline) during mastoidectomy. A standard general anesthetic technique was employed throughout the surgical procedure. At 3, 6 and 24 h after surgery, patients completed questionnaires regarding postoperative dizziness, nausea and pain, with their responses being given on a visual analog scale.

RESULTS

There were no postoperative complications in either group. Compared to the placebo group, the dexamethasone group showed reduced postoperative dizziness and reduced nausea (p<0.05 for both) at 24 h postoperatively. Compared to the placebo group, dexamethasone had no effect on postoperative pain.

Superior canal dehiscence: review of a new condition

A new cause of sound and pressure induced vertigo, superior canal dehisence, is described. Auditory manifestations include hyperacusis to bone-conducted sounds and conductive hearing loss with normal acoustic reflexes. The diagnosis is reached by a directed history, documentation of upward and torsional nystagmus evoked by sound and pressure, and radiology. Acoustic reflexes and VEMP (vestibular evoked myogenic potentials) aid in the identification of patients with an apparent conductive loss with normal acoustic reflexes or have an asymptomatic dehiscense on radiology. Treatment involves avoidance of the precipitating stimuli. Surgical treatment, by resurfacing the dehiscence, is considered in patients with more severe symptoms.

Can low frequency sound stimulation during posturography help diagnosing possible perilymphatic fistula in patients with sensorineural hearing loss and/or vertigo?

Perilymphatic fistula (PLF) is often difficult to diagnose because of the similar symptomatology, such as vertigo, tinnitus and hearing loss, which is found in several inner ear diseases. We attempted to correlate a positive result of low frequency sound (LFS) stimulation tests in posturography with the presence or absence of a PLF confirmed by transtympanic endoscopy in 209 patients with various inner ear diseases (Meniere's disease ( n=128), vestibulopathy ( n=41), cochleopathy ( n=28) and sudden deafness ( n=12). LFS provoked unsteadiness in posturography without PLF in 24 patients with Meniere's disease, in 5 patients with vestibulopathy, in 3 patients with cochleopathy and in 2 patients with sudden deafness. In one patient, tympanoscopy revealed fistula in the round window membrane that was covered with a fibrinous layer. In four cases there was abnormal light reflex in the round window but without PLF. In eight cases, Hennebert's sign was present with nystagmus, without PLF. We conclude that pathological responses to the LFS test in posturography can also be encountered in other inner ear diseases without PLF.

Ondansetron and dexamethasone in middle ear procedures

A randomised, double-blind study was conducted on 90 ASA I & II patients undergoing middle ear surgery to compare the efficacy of ondansetron, dexamethasone and a combination of Ondansett on+dexamethasone for the prevention of postoperative nausea and vomiting. Group I patients received ondansetron (0. 1 mg/kg), group IIpatients received dexamethasone(0.1z mg./Kg) while group III received ondansetron (0.1 mg./kg) + dexamethasone (0.15 mg/kg), 10 minute before induction of general anaesthesia. A standardised general anaesthetic technique was employed through out. A complete response, defined as no postoperative nausea and vomiting and no need for another rescue antiemetic during the first 4 hours after anaesthesia was achieved in 58%, 55% and 83% of patients who had received ondansetron, dexamethasone and ondansetron + dexamethasone respectively. The corresponding incidence during the next 20 hours after anaesthesia was 54%, 47% and 85%. No clinically important adverse effects were observed in any of the groups. We conclude that prophylactic therapy with ondansetron +dexamethasone,one is superior in the prevention of postoperative nausea and vomiting after middle ear surgery.

CT evaluation of bone dehiscence of the superior semicircular canal as a cause of sound- and/or pressure-induced vertigo

PURPOSE

To describe the computed tomographic (CT) findings at different collimation widths associated with superior semicircular canal (SSC) dehiscence syndrome and to determine the frequency of these findings in a control population.

MATERIALS AND METHODS

Temporal bone CT scans with 1.0-mm and/or 0.5-mm collimation were obtained in 50 patients with sound- and/or pressure-induced vestibular symptoms. The control population consisted of 50 patients undergoing CT at 1.0-mm collimation and 57 patients undergoing CT at 0.5-mm collimation for other reasons.

RESULTS

SSC dehiscence was documented on CT scans in all 36 patients with the clinical syndrome, with bilateral findings in six patients. Six other patients without specific clinical signs appeared to have dehiscence on 1.0-mm-collimated scans. Intact bone overlaying the SSC was subsequently identified with 0.5-mm-collimated CT in each case. On the 1.0-mm-collimated scans in 50 control patients, an area judged as possible or definite dehiscence was identified in 18 of 100 ears. The bone overlaying the SSC was intact in each of the 114 control ears evaluated with 0.5-mm-collimated CT. CT findings from the patients with vestibular symptoms combined with those in the control population indicated that the positive predictive value of an apparent dehiscence in the diagnosis of SSC dehiscence syndrome improved from 50% with 1.0-mm-collimated CT with transverse and coronal images to 93% with 0.5-mm-collimated CT with reformation in the plane of the SSC.

CONCLUSION

The positive predictive value of CT in identification of SSC dehiscence syndrome improves with 0.5-mm-collimated helical CT and reformation in the SSC plane.

Low-dose dexamethasone reduces nausea and vomiting after tympanomastoid surgery: a comparison of tropisetron with saline

PURPOSE

The aim of the study was to evaluate the efficacy of low-dose dexamethasone sodium phosphate (5 mg) on the prophylaxis of nausea and vomiting after tympanomastoid surgery. Tropisetron hydrochloride (2 mg) and saline were used as controls.

MATERIALS AND METHODS

One hundred twenty patients (n = 40 in each of 3 groups) undergoing general anesthesia for tympanomastoid surgery were enrolled in this randomized, double-blind, placebo-controlled study. Following endotracheal intubation, group 1 received intravenous dexamethasone 5 mg, whereas groups 2 and 3 received intravenous 2 mg tropisetron and saline, respectively. Several parameters connected with the occurrence of postoperative nausea and vomiting were evaluated.

RESULTS

Dexamethasone 5 mg significantly reduced the total incidence of nausea and vomiting by 40% (P =.002). Dexamethasone also reduced the incidence of vomiting episodes by more than 4-fold (P =.03) and the incidence of patients requiring rescue antiemetics (P =.02). Tropisetron at a 2-mg dose did not exhibit any significant antiemetic effect.

CONCLUSIONS

Dexamethasone sodium phosphate 5 mg was more effective than 2 mg tropisetron hydrochloride and saline in the prevention of nausea and vomiting after tympanomastoid surgery.

Use of dexamethasone on the prophylaxis of nausea and vomiting after tympanomastoid surgery

OBJECTIVE

The aim of this study was to evaluate the prophylactic effect of dexamethasone on postoperative nausea and vomiting (PONV) in patients undergoing tympanomastoid surgery.

STUDY DESIGN

Eighty patients (n = 40 in each of two groups) undergoing tympanomastoid surgery under general anesthesia were enrolled in this randomized, double-blind, placebo-controlled study.

METHODS

After tracheal intubation, group 1 received 10 mg dexamethasone intravenously, whereas group 2 received saline intravenously. Several parameters concerning with the occurrence of PONV were evaluated.

RESULTS

We found that dexamethasone reduced the total incidence of nausea and vomiting by 45%, with a 95% confidence interval of 26% to 64% (P <.001). Furthermore, dexamethasone reduced the incidence of vomiting episodes >4 times and the incidence of patients requiring rescue antiemetics (P <.05).

CONCLUSION

Dexamethasone at a dosage of 10 mg administered intravenously is effective in preventing PONV in patients undergoing tympanomastoid surgery.

Relationship of the utriculus and sacculus to the stapes footplate: anatomic implications for sound-and/or pressure-induced otolith activation

One hundred thirty human temporal bones that were sectioned in the vertical plane were examined to evaluate the relationship between the stapes footplate and the otolith organs. The shortest distance between the footplate and the utriculus was 0.58+/-0.10 mm in the posterior third of the oval window, 1.04+/-0.20 mm in the middle third, and 1.51+/-0.20 mm in the anterior third. The distance from the sacculus to the footplate was 1.33+/-0.20 mm in the middle third of the oval window and 1.31+/-0.18 mm in the anterior third. Membranous connections extending between the utriculus and the footplate were found in 26% of temporal bones. These membranous connections in coexistence with additional anatomic factors such as stapes hypermobility and/or dehiscence of bone within labyrinthine structures may predispose patients to sound- and/or pressure-induced otolith activation. The findings may have implications for different causes of the Tullio phenomenon.

Surgeon's experience as a factor for emetic sequelae after middle ear surgery

PURPOSE

To test the hypothesis that an experienced surgeon is associated with less postoperative nausea and vomiting (PONV).

METHODS

A post hoc analysis was done on the data of 167 patients from 3 randomized studies on the prevention of PONV, with transdermal scopolamine, ondansetron and propofol, in middle ear surgery under general anaesthesia.

RESULTS

The patients in the residents' group suffered more from PONV (69% vs. 42%, P < 0.01) and from retching or vomiting (52% vs. 23%, P < 0.001) than those in the specialists' group. The proportion of patients needing droperidol was also higher in the residents' group (66% vs. 27%, P < 0.001). The durations of anaesthesia and surgery seemed to correlate positively with PONV. In matched-pair analysis, residentship was confirmed as a risk factor for emetic symptoms. In the residents' group, prophylaxis of PONV resulted in a decrease in retching and vomiting from 71% to 29% (P < 0.01), and in patients needing droperidol from 87% to 46% (P < 0.01).

CONCLUSION

The patients operated by residents need more aggressive prophylaxis for PONV than those operated by specialists in middle ear surgery.

Auditory and visual interactions in postural stabilization

The interaction and subsequent interpretation of sensory feedback from different modalities are important determinants in the regulation of balance. The importance of sound in this respect is not, as yet, fully understood. The aim of the present study was to determine the interaction of specific auditory frequencies and vision on postural sway behaviour. The frequencies employed represent the geometrical mean of 23 of the 25 critical bandwidths of sound, each presented at two loudness levels (70 and 90 phones). Postural sway was recorded using a biomechanical measuring platform. As expected vision had a highly significant stabilizing effect on most sway parameters. The frequency of the sound, however, appeared to influence the regulation of anteroposterior sway, while increasing loudness tended to increase mediolateral sway. At some frequencies the sound appeared to compensate for the lack of visual feedback. The interaction of sound and vision, particularly in combinations that lead to increased sway behaviour, may have implications in the occurrence, and possible prevention, of industrial accidents.

Myogenic potentials generated by a click-evoked vestibulocollic reflex

Electromyograms (EMGs) were recorded from surface electrodes over the sternomastoid muscles and averaged in response to brief (0.1 ms) clicks played through headphones. In normal subjects, clicks 85 to 100 dB above our reference (45 dB SPL: close to perceptual threshold for normal subjects for such clicks) evoked reproducible changes in the averaged EMG beginning at a mean latency of 8.2 ms. The earliest potential change, a biphasic positive-negativity (p13-n23), occurred in all subjects and the response recorded from over the muscle on each side was predominantly generated by afferents originating from the ipsilateral ear. Later potentials (n34, p44), present in most but not all subjects, were generated bilaterally after unilateral ear stimulation. The amplitude of the averaged responses increased in direct proportion to the mean level of tonic muscle activation during the recording period. The p13-n23 response was abolished in patients who had undergone selective section of the vestibular nerve but was preserved in subjects with severe sensorineural hearing loss. It is proposed that the p13-n23 response is generated by activation of vestibular afferents, possibly those arising from the saccule, and transmitted via a rapidly conducting oligosynaptic pathway to anterior neck muscles. Conversely, the n34 and p44 potentials do not depend on the integrity of the vestibular nerve and probably originate from cochlear afferents.