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Trial registered on ANZCTR


Registration number
ACTRN12622000838718p
Ethics application status
Submitted, not yet approved
Date submitted
22/04/2022
Date registered
15/06/2022
Date last updated
15/06/2022
Date data sharing statement initially provided
15/06/2022
Type of registration
Prospectively registered

Titles & IDs
Public title
Microvascular Decompression for Unilateral Pulsatile Tinnitus- A Prospective Randomised Multicenter Study
Scientific title
The Efficacy of Microvascular Decompression for Unilateral Pulsatile Tinnitus- A Prospective Randomised Multicenter Study
Secondary ID [1] 306956 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Pulsatile tinnitus secondary to vascular compression of vestibulocochlear nerve 326071 0
Condition category
Condition code
Neurological 323382 323382 0 0
Other neurological disorders

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Participants with unilateral pulsatile tinnitus, secondary to vascular compression and without any other identifiable cause, and have exhausted maximal medical therapy, will be eligible for enrolment. This trial will consist of two groups - a control and an intervention group. Participants will be randomised to either group.

The intervention group will consist of participants undergoing surgery in the form of microvascular decompression of the hearing nerve (vestibulocochlear nerve). Microvascular decompression is already an established surgical treatment for patients with trigeminal neuralgia (vascular compression of trigeminal nerve), hemifacial spams (vascular compression of facial nerve) and glossopharyngeal neuralgia (vascular compression of glossopharyngeal nerve). Microvascular decompression of the vestibulocochlear nerve has been described in the literature with promising results, although large scale trials have never been performed. This trial aims to go beyond what exists in the literature by being the first randomised study to investigate the efficacy of microvascular decompression for pulsatile tinnitus. If found to be effective in providing symptom relief, then this will offer patients affected with this condition with another line of treatment. Participants in this group will continue receiving maximal medical therapy as they were previously (e.g. CBT, masking devices or hearing aids), and this will continue for the duration of this study i.e. for 90 days post-op and beyond.

The surgery will be performed by both and ENT and Neurosurgeon as a joint procedure, and will take 2-3hrs. Intra-operatively, the offending vessel (artery or nerve) compressing the vestibulocochlear nerve will be separated. Participants will still continue to receive maximal medical therapy for the duration of the trial, without interruption. Operation reports will be audited by the investigators.
Intervention code [1] 323401 0
Treatment: Surgery
Comparator / control treatment
Participants in the control group will consists of patients with pulsatile tinnitus secondary to vascular compression, and this group will continue with maximal medical therapy that they are already on by their treating physician, and no changes will be made to this during the study period. This may include cognitive behavioural therapy, hearing aids or masking devices. This will allow direct comparison of the intervention (patients undergoing microvascular decompression) to determine whether surgery can be offered as an additional line of treatment for these patients. Medical therapy will continue throughout the duration of the study i.e. for 90 days to allow participants to complete the assessments at each time interval (30 and 90 days).
Control group
Active

Outcomes
Primary outcome [1] 331117 0
The primary outcome is surgical treatment efficacy compared to control. using the tinnitus functional index.
Timepoint [1] 331117 0
30 and 90 days after completion of treatment (date of surgery) for the intervention group, and 30 and 90 days after enrolment for the control group.
Primary endpoint is 90 days
Primary outcome [2] 331337 0
The primary outcome is surgical treatment efficacy compared to control using the tinnitus handicap index
Timepoint [2] 331337 0
30 and 90 days after completion of treatment (date of surgery) for the intervention group, and 30 and 90 days after enrolment for the control group.
Primary endpoint is 90 days
Primary outcome [3] 331338 0
Treatment efficacy assessed as resting state functional activity of the auditory cortex measured using functional near-infrared spectroscopy
Timepoint [3] 331338 0
30 and 90 days after completion of treatment (date of surgery) for the intervention group, and 30 and 90 days after enrolment for the control group.
Primary endpoint is 90 days
Secondary outcome [1] 408830 0
The secondary outcome is to assess the morbidity associated with microvascular decompression of the vestibulocochlear nerve. This includes post-operative complications, such as CSF leak, partial/complete hearing loss, vertigo, DVT/PE, facial weakness, speech/swallow disturbance, infection (meningitis/abscess), wound breakdown and post-operative haematoma.

All patients will be followed up in the immediate post-operative period, and post-discharge in 4-6 weeks in the outpatient clinic setting. In both instances, any morbidity associated with the procedure will be recorded. This will be assessed in both groups.
Timepoint [1] 408830 0
Morbidity associated with microvascular decompression will be recorded up to the 6 week mark when patients are followed up.

Eligibility
Key inclusion criteria
The inclusion criteria are as follows: 1) age 18-75 years; 2) unilateral pulsatile tinnitus with some preservation of ipsilateral hearing; 3) MRI brain with no alternative major abnormality accounting for symptoms and there is identifiable vascular compression of the vestibulocochlear nerve; 4) all conservative therapies have been trialled and exhausted without significant symptom relief; 5) pre-op assessment by audiometry, vestibular testing and assessment by either a consultant ENT surgeon or Neurosurgeon who deem that microvascular decompression (MVD) is indicated; 6) patients with an American Society of Anaesthiology (ASA) score of I/II; and 7) patients have suffered from pulsatile tinnitus for >12 months
Minimum age
18 Years
Maximum age
75 Years
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
The exclusion criteria are as follows: 1) non-pulsatile tinnitus; 2) bilateral tinnitus; 3) abnormal MRI brain with significant structural abnormality; 4) previous retrosigmoid craniotomy or radiotherapy to the posterior fossa of the brain; 5) severe medical co-morbidities with ASA score III/IV; 6) patients with psychiatric comorbidity; 7) total deafness; and 8) inability to consent.

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Yes

Allocation concealment will be carried out by contacting the holder of the allocation schedule who is not on site.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Randomisation of participants will be performed by using a randomisation table on a computer. Each participant will be assigned a number and accordingly assigned to either the intervention or control group.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
Data collected from the study participants, including demographic information, pre and
post-operative testing and clinical information will be de-identified and stored electronically
on a password protected computer in a locked office at both of the study sites (Melbourne Health and Monash Health). fNIRS data at the Bionics Institute will be de-identified and stored electronically on a password protected computer at the Bionics Institute, and only Associate investigators from the BI will have access to this.

Patient demographics, in de-identified format, will be uploaded onto a Microsoft Excel (Microsoft
Corp., Redmond, Washington, United States) document. It will then be transferred to statistical and
graphical programs including GraphPad Prism (GraphPad Software Inc., La Jolla, California, USA)
and Stata/IC 15 (StataCorp LLC, College Station, Texas, USA) for further analysis and generation of
figures and tables. Data and images will be stored onto a password protected hard drive that will be
securely locked in the Principal Investigator’s Office.

Categorical data will be calculated and analysed using Chi-Squared or Fisher’s Exact Test to examine
any correlation between two data sets. Continuous data will be reported as a mean with standard
deviation and analysed using Student’s T/Analysis of Variance Tests of parametric variables, or with
Mann-Whitney U/Kruskal-Wallis Test for non-parametric variables. A p-value of < 0.05 will be
considered statistically significant.

The sample size is 23, based on a 95% confidence interval, with 5% margin of error, and a 50% population proportion. The estimated population size over the 12-month period is 13 per each site.

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
1/08/2022
Actual
Date of last participant enrolment
Anticipated
31/05/2023
Actual
Date of last data collection
Anticipated
31/08/2023
Actual
Sample size
Target
30
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
VIC
Recruitment hospital [1] 22212 0
Monash Medical Centre - Clayton campus - Clayton
Recruitment hospital [2] 22213 0
Royal Melbourne Hospital - City campus - Parkville
Recruitment postcode(s) [1] 37373 0
3050 - Parkville
Recruitment postcode(s) [2] 37375 0
3052 - Parkville
Recruitment postcode(s) [3] 37372 0
3168 - Clayton
Recruitment postcode(s) [4] 37374 0
3168 - Notting Hill

Funding & Sponsors
Funding source category [1] 311274 0
Hospital
Name [1] 311274 0
Monash Health
Country [1] 311274 0
Australia
Funding source category [2] 311298 0
Hospital
Name [2] 311298 0
Melbourne Health
Country [2] 311298 0
Australia
Primary sponsor type
Hospital
Name
Monash Health
Address
246 Clayton Road, Clayton, VIC, 3168
Country
Australia
Secondary sponsor category [1] 312633 0
Hospital
Name [1] 312633 0
Melbourne Health
Address [1] 312633 0
300 Grattan Street, Parkville, VIC, 3050
Country [1] 312633 0
Australia

Ethics approval
Ethics application status
Submitted, not yet approved
Ethics committee name [1] 310781 0
Monash Health HREC
Ethics committee address [1] 310781 0
246 Clayton Road, Clayton, VIC, 3168
Ethics committee country [1] 310781 0
Australia
Date submitted for ethics approval [1] 310781 0
27/04/2022
Approval date [1] 310781 0
Ethics approval number [1] 310781 0

Summary
Brief summary
Tinnitus is a common presentation whereby patients experience a ringing or buzzing sound in the absence of external noise, and these symptoms can be quite debilitating for the affected individual. Pulsatile tinnitus represents a subtype that may be caused by compression exerted by an arterial loop or vein against the vestibulocochlear nerve as it exits the brainstem en-route to the inner ear. Microvascular decompression (MVD) is already routinely performed for the treatment of other neurovascular compression syndromes with positive results, including trigeminal neuralgia (compression of trigeminal nerve), hemifacial spasm (compression of facial nerve) and glossopharyngeal neuralgia (compression of the glossopharyngeal nerve). There is a limited volume of worldwide literature which suggests that surgery (microvascular decompression of the acoustic nerve) to treat this condition may be of benefit in selected cases. The evidence is limited to small case series, and several systematic reviews, but no randomised trials have been performed to date.

The objective of this study is to go beyond what we already know from the limited literature by carrying out a randomized multi-centre controlled trial, investigation to results of microvascular decompression of the acoustic nerve. The primary endpoint is treatment efficacy compared to control. The secondary endpoints examine the safety and prognostic factors that would lead to a more favourable outcome following surgery.

A small case series of patients recruited from two large health networks in Melbourne (Melbourne Health and Monash Health) will be selected according to the type and severity of their tinnitus. Inclusion criteria include: 1) patients with unilateral pulsatile tinnitus, 2) there is an identifiable compression of their vestibulocochlear nerve by an arterial loop or vein on pre-operative imaging, 3) have suffered from pulsatile tinnitus for > 12 months, 4) have attempted other conservative measures, 5) age 18-75 years and 6) able to consent for participate in the study.

Patients meeting the inclusion criteria and who consent to participation in the study will be randomised to either continue with 1) best medical management (control arm) or 2) undergo microvascular decompression via a retrosigmoid craniotomy at either of the two study centres (intervention arm).

This surgery involves a general anaesthetic, and posterior fossa craniotomy, identification of the vestibulocochlear nerve and compressing vessel, and removing this vessel away from the nerve to relieve the pressure on it. The primary outcome measure is the surgical efficacy for treating pulsatile tinnitus.

Based off the existing literature, it is hypothesised that at least 60% of participants will experience some symptom relief post-surgery.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 118842 0
A/Prof Leon Lai
Address 118842 0
Monash Medical Centre
246 Clayton Road, Clayton, VIC, 3168
Country 118842 0
Australia
Phone 118842 0
+61 3 9594 6141
Fax 118842 0
Email 118842 0
leon@drleonlai.com
Contact person for public queries
Name 118843 0
A/Prof Andrew Morokoff
Address 118843 0
Royal Melbourne Hospital
300 Grattan Street, Parkville, VIC, 3050
Country 118843 0
Australia
Phone 118843 0
+61 3 93427000
Fax 118843 0
Email 118843 0
morokoff@unimelb.edu.au
Contact person for scientific queries
Name 118844 0
Dr Rebecca Limb
Address 118844 0
Monash Medical Centre
246 Clayton Road, Clayton, VIC, 3168
Country 118844 0
Australia
Phone 118844 0
+61 407645393
Fax 118844 0
Email 118844 0
beckylimb06@yahoo.co.uk

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
No individual data would be made available to the public
The results of this study will be published in peer-reviewed journals and presented in a de-identified manner where there is no way of identifying individual participants.


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.