The Dangers of Microsuction

You do not need to go to the Mayo Clinic to have ear wax removed. Are you going for anything else?

Can you possibly see a local ear specialist? Mayo Clinic is great, but flying there to have ear wax removed seems not the best use of resources. They have many highly specialized physicians and nurses. I had a spinal tap there and the nurse who did the procedure was specifically a spinal puncture nurse. That was her area of expertise and what she did all day, every day.

But locally I saw an ear specialist who did intratympanic steroid injections and multiple ear surgeries a week. I would trust him to remove ear wax, moreso than a PA who likely does not regularly remove wax. I do not think ear wax is a common complaint at Mayo.

Are you certain there is wax on your eardrum? If there is anything wrong with your eardrum causing it to not move correctly, flying may be uncomfortable and add to your discomfort.

 

Hi @guys pls help

OK, I read your post so understand you have a dilemma.

I can't tell you what is the best thing for you to do, but I can tell you what I would do in the same situation. I would definitely stay away from microsuction, for sure. I had wax removed by this method (ent didn't give me any other option and I was unaware of the risks) and despite putting drops in 2-3 times a day for almost 2 weeks prior to seeing the ent, the procedure caused permanent tinnitus, hyperacusis and hearing loss (all of which I didn't have before). The suction was very loud and the procedure caused clarinetting as the wax blocked the end of the suction tube. This was my experience, and for that reason I would never risk having microsuction again. If I could turn back the clock I would give it more time with the drops, and maybe try softening the wax a little when under the shower. Obviously this is my opinion from my dreadful experience. I hope you manage to come to a decision you're comfortable with.

 

@guys pls help

You have two options. Either to carry on as you are and do nothing or get the earwax removed using one of the three methods discussed in this thread. I advise you to choose the latter as a build up of earwax will eventually cause you problems also discussed in my posts. I advise you to follow the advice your ENT Dr gives you on which method he or she recommends. Although I have mentioned I had microsuction 3 times and water irrigation the same without problems. I have had my earwax removed by a 3rd method.

Twenty two years ago when I first got tinnitus I had my ears syringed by my GP the "old fashioned" way that is no longer used today, as it's considered too harsh and abrasive for the ear and auditory system. This is where a metal canister is filled with warm water and squirted into the ear under pressure to flush out the wax. My GP was very good and knew about tinnitus. She wouldn't let the practice nurse perform this procedure as was the usual case. I was advised to use eardrops for 10 days and fortunately had no problems.

I wish you well
Michael

 

@Tinker Bell Thank you very much for your response Tinker Bell. In October, after I stopped overprotecting my ears with frequent ear muff and ear plug use, my tinnitus (which used to be a high pitch monotone ring) and hyperacusis seemed to fade almost completely away, giving me hope that over-sensitivity from over-protection/anxiety was the cause of my ear problems.

However, when I was fast tracked to see a local ENT in Canada (2 month wait time from the fast track), the audiologist there could not get a seal on my ears with an ART/tympanometry 2-in-1 instrument, and so jammed the instrument into my ears repeatedly, trying to get a seal, and shooting air into my ears. It is this incident, combined with my previous frequent ear plug use, that I believe may have lodged and impacted the heavy wax build up in my ear into my left ear drum; This resulted in a COMPLETELY NEW, atonal, constant ringing that has not gone away since that incident.

My ear drum is completely occluded by ear wax and so it is not possible to see the state of my ear drum. There is of course, no guarantee that there is any impaction at all.

I do not know how experienced the PA's who do wax removal are at mayo, I would have hoped that they do it all the time like the spinal puncture nurse you saw.

I called my local city hospital ENT department, and unlike mayo, they refused to give me any information regarding ear wax removal until I get a referral except that instead of a 1 year or 2 year wait time for ENT like GP's in Canada say it can be, they could maybe get me in on a booking out 2 weeks to 2 months estimate depending on how urgent it was, and the ENT would have to order the wax removal.

I went to a GP this morning who was happy to get me a referral, but I wanted to look into which ENT to get a referral to; at this point I am willing do go to US, uk, or stay in Canada, wherever I can get the safest/most reliable wax removal done when it gets to that point of my decision making. I have been debilitated for months due to my tinnitus and want to make the most informed decision I can, because even though it is such a common procedure, from what I have read, it seems to be an area of medicine drowning in litigation accordingly.

Let me know if you have any suggestions of ENT's you would suggest as well. Thanks again.

 

@Blue28 Thank you so much for your response Blue. Right now, since I have some hope that it is ear wax causing my tinnitus, I have decided to at least try and use ear drops a little longer.

I have used olive oil in my ears twice a day for 3 weeks so far with no success but will continue to do so.

And than maybe follow these instructions from a home remedy link from my local health services instructions:

"Once the wax is loose and soft, all that is usually needed to remove it from the ear canal is a gentle, warm shower. Direct the water into the ear, then tip your head to let the earwax drain out."

From this link- https://myhealth.alberta.ca/Health/aftercareinformation/pages/conditions.aspx?hwid=uh2941

I will try that, and in the mean time, if I ever get into a worsening condition of state of health, I'm going to try and find reputable people/places to have ear wax removed, like Michael said, with the opinion of what an ENT thinks is best, but I hope irrigation or manually, but I can't tell what I will decide in the future to be honest, maybe I will end up rolling the dice with microsuction.

 

Thank you for providing more information; but I am confused. Do you actually have impacted wax or are you assuming you do?

The Mayo Clinic is one of the best medical facilities in the world. They regularly see very rare and complex medical cases. That is why they have puncture nurses for spinal taps. I do not think they have PAs who specialize in ear wax removal, as I said before that is likely not a common patient complaint.

I realize you are nervous about the procedure, but there is no reason to take an international flight for ear wax. If you have impacted wax, the flight would likely make things worse. Seek out local ENTs and find one who does manual wax removal.

 

You're welcome @guys pls help

 

Hey Blue, yeah my hearing is 10db worse at higher frequencies than it used to be, I don't have hyperacusis however as I've had tinnitus for so long I managed to nip it in the bud before it started. No offense Michael Leigh but you realize that the claranetting that occurs during microsuction (this is what causes tinnitus and hearing loss) can occur with both soft and hard wax, just telling people to use olive oil is honestly quite infuriating as I did and I have hearing loss and incrediblyy loud tinnitus now soooo yeah. The noise generated during claranetting can be around 150 db so yeah. Also for anyone who had it done without using drops, what you are doing when you tell them that they should have used drops is victim blaming and shifting the blame from the incompetent doctor onto the actual victim, for someone who claims to have counseled people it boggles my mind that you dont realise how this would make them feel horrible and cause them to blame themselves.

 

Hey @Tinker Bell

I don't know if I have impacted wax and I'm not assuming I do.

My ear canal is completely blocked by wax so the ear drum can't be scene to tell if there's an impaction.

And the new ear pain/new tinnitus that occurred after the incident of when I think the wax was pushed deeper into my ear I just thought it may be a likely possibility worth pursuing as the cause of my tinnitus.

I will ask ENT dept. at mayo if the PA's do it routinely every day or if it is indeed not a common complaint like you suggest cause I do think that is important.

In regards to finding a local ENT, from what I have been told by GP's in Canada so far is that the wait time could be as long as even a year or 2, and even if I do wait a year, I don't really want to wait a year to find out that the ENT I was sent to uses a metal syringe and has barely any experience with wax removal.

So I will keep looking, and seeing if I can find both a good place/person for wax removal by whatever method I decide on if or when it comes to that, and if there are any shorter wait times for a wax removal procedure instead of a full consultation.

From what I read on this forum about people's experiences in the United States with seeing ENT's and the services they've been provided, it may be easier/faster for me to find what I need in the US, which I wouldn't mind flying for at all if it means I get what I'm looking for.

 

Hi everyone. Signed up to comment on this thread. I also have hearing loss, severe tinnitus from both ear irrigation methods, but noticed the hearing loss right after the ENT cleaned my ears using the micro-suction. He was using it for so long, i had very high pitched noises from the machine it hurt me so much i kept telling him to stop, but he said he has to remove everything so i endured it. Well now i am stuck with severe tinnitus, hearing loss, blocked feeling in my ears and now my ears are again full of wax and i dont know how to safely remove it please help

oh and nobody told me to soften the wax before the procedure. Ive done this procedure 4x and the last 2 was the worst

 

Hello @NoMeaning25

I am sorry to hear of the difficulties that you have with microscution. You should have been advised to administer eardrops 3 times a day to each ear for 7 to 10 days before having the wax removed. This should also be done, if the wax is going to be removed by: ear irrigation or manually removal using tools - curette.
You have 4 choices. Have the earwax removed using: Microsuction, irrigation or manual removal. Use eardrops and hope that the wax exits from the ear naturally. If you do nothing and carry on as you are, then further problems may occur:

Ear infection
Increased tinnitus
Dizziness
Hearing loss
Earache leading to severe pain.
Fever
A feeling of fullness in the ear

Try and get the wax removed at an ENT clinic in hospital. I go to other tinnitus forums and surprised to learn, some people have microsuction and do not use any eardrops before this procedure and have no problems. I think this is risky and not a good idea. People have contacted me that have had microsuction and used eardrops and their tinnitus has been made worse. Some have also had ear irrigation and manual removal and used eardrops and have also had problems.

I have had earwax removed by microsuction 3 times and ear irrigation the same and had no problems.

The choice is yours.
I wish you well
Michael

 

Hi @NoMeaning25
I'm so sorry to hear that you are another victim of microsuction, it amazes me that this procedure is still permitted when clearly it can have catastrophic consequences. The loud, high pitched noise you experienced was probably clarinetting, where the wax or dermal flakes obstruct the suction tool. I had this happen to me too.

Which country did you have the procedure done? Were you asked to sign a disclaimer?

If I were you and needed wax removed again, I'd try to find a very skilled ENT and have it removed manually. No suction and no irrigation.

 

Hi there thanks for responding, I stay in South Africa and i did not sign any disclaimer or told of the dangers.It has been 2 years ago though and I only figured it all out yesterday, this could be the only reason for my hearing loss etc, i am only 29 years old i am not supposed to be having hearing loss of a 60 year old and i noticed the deafness straight afterwards, but the ENT told me its normal, i guess it wasn't.

I do really not feel comfortable putting anything in my ears, so how will i manage to put olive oil in my ears for 10 days? I have quite severe anxiety and cant handle the feeling of my ears completely clogged up and i know this is what will happen when i put oil in my ears. How can i manage this?

I have found a good ENT but he only has an opening in April this year so i will need to wait

I actually never had this wax build up until right after they used irrigation to clean out my ears in 2009, but i never had fullness, tinnitus, or any other issues up until 2016 when they used microsuction and it literally felt like he was sucking my whole sinuses out

 

Unfortunately @NoMeaning25 using eardrops 3 times a day for 10 days is likely to clog up your ears as it did mine I'm not going to lie to you. It is up to you to decide what to do. Your earwax will have to be removed at some time if it cannot exit the ear naturally, or you risk having additional problems like I've mentioned above. Whatever method of removal you choose, I advise you to use eardrops at least twice a day for 7 to 10 days before the procedure.

Another thing. It is not easy to prove negligence or malpractice against someone in the medical profession as one has to have deep pockets to pay lawyers. The medical profession can afford the best lawyers. I know someone that tried this and regretted it.

Best of luck
Michael

 

Doctors/ENTs are absolutely worthless. My ENT gave me a list of possible conitions that are casuing my T, even though i said it is Acoustic Trauma she was like it could be also all of these lol

 

Had microsuction treatment today. I had read previously about the pros and cons of ear syringing and microsuction (and doing without) and this thread was helpful in informing me about this. For me doing nothing wasn't really an option - the build-up of wax in one ear had really impacted on both my hearing and worsened my tinnitus. So I decided on the microsuction option and afterwards both my hearing and tinnitus (in the treated ear) have improved.

I would say, however, it really is worth choosing your ear clinic carefully. From a UK perspective I was happy to pay to see a specialist audiologist rather than to take a chance - and a long wait - on our NHS with its often inexperienced and over-worked practice nurses. The audiologist I saw was helpful and experienced - we discussed my concerns that my tinnitus might be negatively impacted by the procedure and agreed that if I felt the sound was too loud at any stage to say and they would immediately stop the procedure.

I'm glad that I had the microsuction - but it pays to choose carefully and discuss any concerns beforehand.

 

I haven't known this about microsuction. I had microsuction 6 years ago, then the ENT gave me ear drops after the microsuction. And after that I developed otitis.

This year, I had microsuction from another ENT, he didn't gave me ear drops after the microsuction ( he had a good rep as an ENT ). After that my T went bilateral and so I went to another ENT. After microsuction, I had hyperacusis and my T became bilateral. This year, both ENTs got me an audiogram and tympanogram. Comparing the between previous and current audiogram and tympanogram, my good ear now has worst hearing than before in only 2 weeks time.

I was lucky to have only one ear microsucted this time. If he microsucted the ear which had the acoustic trauma, I would have gotten significant hearing loss.

 

I would like to join Blue28 and others, who have had their hearing damaged by the microsuctioning of their ears.
I underwent the vacuum otomicrotoilet procedure here in Christchurch NZ at an ear hygiene clinic in the suburb of Ferrymead. The procedure was carried out so roughly that one eardrum was pierced and both ears are now deaf to frequencies beyond 2KHz. Any sounds, voices, music etc that carries frequencies above the 2KHz point, are heard as crackly. chopped up sounds much like a damaged speaker...this condition is known as Hydracusis. I also know now that in the hands of unskilled and or simply rough operators, the microsuction process can induce painful levels of sound in excess of 140dB in the ear canal, and its this level of sound that destroys nerve cells in the inner ear ( cochlear). Unfortunately I have no redress here in NZ for medical malpractice as we have a Govt setup medical compensation system which is supposed to help in situations like this. However someone like me has to find a way to prove that my previous hearing before the procedure was okay...and this is just an impossible task...mainly because when you approach any ENT specialist, you will find that they use the procedure themselves and fully back the use of the equipment. One such specialist is on record sa saying to me that instances of damage to patients undergoing this procedure are "vanishing rare". I suspect that its not quite so rare, as I am just another unfortunate person who has lost their previously good hearing to this procedure.

 

Here's are some studies I found relating to microsuction sound levels and safety.

-

Noise levels generated within the external auditory canal during microsuction aural toilet and the effect on hearing: a prospective controlled series.

Snelling JD, et al. Clin Otolaryngol. 2009.

Abstract

OBJECTIVES: To measure the noise generated during suction aural toilet and to determine whether there is any clinically measureable effect on audiometric thresholds.

STUDY DESIGN: Prospective, controlled study with 14 patients.

SETTING: The study was conducted in an aural toilet clinic in a district general ENT department.

PARTICIPANTS: Fourteen patients who attend regularly for suction aural toilet to clear cerumen.

MAIN OUTCOME MEASURES: Live direct measurement of noise levels during treatment. Pre-treatment and post-treatment pure tone audiometry.

RESULTS: Microsuction generated a broadband sound with a peak at 2 kHz. Sound levels peaked at over 120 dB(A) in two patients. We found no evidence of any shift in audiometric thresholds following microsuction aural toilet.

CONCLUSIONS: Microsuction is a noisy procedure that is uncomfortable for some patients. However, it does not appear to be sufficiently noisy to produce a clinically detectable threshold shift. We would suggest that it is safe but that the use of non-suction methods or a fine end may on occasion be preferable to improve patient comfort.

-

[Suction-generated noise levels during aural toilet].

Hansen S, et al. Laryngorhinootologie. 2012.

Abstract

BACKGROUND: The use of suction for the removal of foreign bodies or cerumen from the external auditory canal is a common procedure in ENT outpatient centers. Patients' lamentations about high noise levels during microsuction can cause assault charges concerning permanent hearing loss or tinnitus. However, the medical opinion of these cases is difficult because only a small amount of objective data about suction-generated noise is available.

MATERIALS AND METHODS: In this study, noise levels of different suction devices were measured under standardized conditions in an artificial model head (HEAD acoustics, Germany). In a second set-up water and lard (instead of cerumen) were suctioned from an artificial external auditory canal, which was coupled with a noise mediator (Mediator 2238, Brüel & Kjaer, Denmark).

RESULTS: There was a significant influence of the inner diameter of the sucker on the noise level. A sucker with a diameter of 1.4 mm generated a noise level of more than 100 dB(A). The suctioning of water generated a maximum noise level of more than 130 dB(LAmax), while the suctioning of lard reached nearly 150 dB(LAmax). The time lapse of both noise and frequency level for lard suctioning was characteristic of a bang.

CONCLUSION: This study demonstrates objective and reproducible data for suction-generated noise levels and could help to evaluate patients' complaints.

-

Suction-generated noise in an anatomic silicon ear model.

Luxenberger W, et al. Eur Arch Otorhinolaryngol. 2012.

Show full citation

Abstract

The objectives of this study were to evaluate noise levels generated during micro-suction aural toilet using an anatomic silicon ear model. It is an experimental study. In an anatomic ear model made of silicone, the eardrum was replaced by a 1-cm diameter microphone of a calibrated sound-level measuring device. Ear wax was removed using the sucker of a standard ENT treatment unit (Atmos Servant 5(®)). Mean and peak sound levels during the suction procedure were recorded with suckers of various diameters (Fergusson-Frazier 2.7-4 mm as well as Rosen 1.4-2.5 mm). Average noise levels during normal suction in a distance of 1 cm in front of the eardrum ranged between 97 and 103.5 dB(A) (broadband noise). Peak noise levels reached 118 dB(A). During partial obstruction of the sucker by cerumen or dermal flakes, peak noise levels reached 146 dB(A). Peak noise levels observed during the so-called clarinet phenomena were independent of the diameter or type of suckers used. Although micro-suction aural toilet is regarded as an established, widespread and usually safe method to clean the external auditory canal, some caution seems advisable. The performance of long-lasting suction periods straight in front of the eardrum without sound-protecting earwax between sucker and eardrum should be avoided. In particular, when clarinet phenomena are occurring (as described above), the suction procedure should be aborted immediately. In the presence of dermal flakes blocking the auditory canal, cleaning with micro-forceps or other non-suctioning instruments might represent a reasonable alternative.

-

Microsuction aural toilet in ENT outpatients: a questionnaire to evaluate the patient experience

Addams-Williams
Eur Arch Otorhinolaryngol (2010)

Results
[...]

A total of 164 patients completed the questionnaire with an average age of 55 years (age range from 18 to 89 years).There were 77 females (47%) and 87 males (53%).

The grade of operator undertaking the procedure is shown in Fig. 1. A large proportion of the procedures was

performed by staff grade and associate specialist doctors (40%).

Aural microsuction was performed on patients with a wide range of otological problems as shown by Table 1.

Overall, 8% reported tinnitus after the procedure, 34% were dizzy during suctioning, 41% were dizzy post aural microsuction, 11% complained of reduced hearing and 28% found the loudness to be unpleasant (Table 1).

Patients with mastoid cavities reported a higher percentage of adverse effects in all categories when compared to those with normal ears (Fig. 2). This is

particularly the case for symptoms of dizziness during and/or after aural microsuction (Table 2). The Chi-squared test with Yates correction used for intergroup comparison showed a significant difference (p\0.001).

Of the patients with normal ears, 66% did not report any adverse side effects from the current procedure versus 16% of patients with mastoid cavities.

Patients with atticotomies, retraction pockets and tympanic membrane perforations also reported higher rates

of adverse side effects. However, the number of patients within those groups is too small to analyse further.

Fifty-three patients (32%) had an infected ear.

Seventy-four patients (45%) did not report any current adverse effects from the aural microsuction procedure.

A total of 44 patients (27%) reported a previous bad experience with aural microsuction (see Fig. 3); 21 of these patients specifically complained of pain. A proportion of these patients did not state the nature of the previous bad experience. Of those patients who reported no previous bad experience of aural microsuction, a proportion would not have undergone this procedure before.

Conclusion
[...]

We would recommend using aural microsuction for short periods of time only and the use of wax hooks and forceps where possible may minimise the risk of complications such as those described here. However, some patients may prefer microsuction as a means of aural toilet and this also needs to be recognised. Clear communication between the patient and the clinician is essential to establish the patient’s preference for treatment method and to allow for informed consent by the patient for the procedure to be undertaken.
-

 

Insane...

 

They pierced an ear drum. That is proof enough to show they were incompetent. They cant turn around and say it was already perforated as they couldn’t perform microsuction on a perforated ear.

 

@Bruce Whitfield

I'm so sorry to hear that you have suffered due to microsuction. It angers me so much that doctors (ENTs especially) and other health professionals are carrying out this procedure with such lack of knowledge and care. I feel so strongly about this as my life has been ruined by this procedure, yet the ENT that caused the damage to my ears is in total denial. I complained and he even went as far as blaming me saying I'm psychologically unstable etc. How can we make the world wake up to such negligence? @Vicki14 and others affected by this procedure what can we do? We need to stand together and make the authorities listen!!!

 

O

Start a Facebook group. If you google the Essure and mesh ones they have been unbelievably successful. I don't think there will be as many patients out there injured by suction but there will be some. Recording of complications in medicine does not appear to be good at all, probably as part medical legal protectionism

 

@brownbear Firstly, thank you for being part of this forum for your valuable contribution to it and sorry to hear that you too have been afflicted by this hellish condition.
Could I ask for your advice please? In June 2016 I visited an Audiologist who ran a local support group which I attended, recommended by the BTA. I wanted really to chat to him about Tinnitus etc. My tinnitus was very mild at that point and after a stressful uncomfortable 2.5hr appointment he suggest I have Microsuction to remove some wax from my right ear. I expressed my concern but he assured me that this was the safest possible method. I asked if I could see the wax and he was a bit frustrated by that and asked his receptionist to fetch the camera and operate as he couldn’t and said it was ‘new equipment’, he also had to get his receptionist to help remote wax which took at least 10 minutes due to narrowest canals! During this appointments he told me that I wasn’t coping very well and that my hearing wasn’t great... both of which were untrue.

Basically I was left with loud Tinnitus, hypercausis, stress, anxiety and other symptoms which have now developed as a result of this horrible experience. What I would like to kindly ask is there ANY WAY on which I can make a complaint to a professional organisation? I have contacted a few law firms but they’ve frustratingly told me that there isn’t enough evidence to sue.

I would appreciate any advice you can offer. Thank you in advance!

 

@Gman Im with you here. I went against my better judgement and has it done. A decision I’ll forever regret. Hope you’re doing ok and that there are better days ahead FOR US ALL x

 

@Vicki14 . So Sorry to hear what happened to you. I expect that if the lawyers don't think there is much chance then there probably isn't. Are you in the U.K.? Did you discuss the case with the hospital PALS team?

 

@brownbear

Thank you for your reply! Just seeing this now!!!

 

I may have suffered hearing loss and tinnitus in one ear after recent microsuction. As with others here I wasn't given any warnings as to the volume of the noise involved in microsuction, both the normal loud hissing and the much louder "bangs" when the tip blockages clear. Neither was I consulted on whether I had sensitivities to loud sounds, which I have.

I read a research paper stating no hearing losses were measured after microsuction. But to make that measurement they would need to have conducted a baseline hearing test before the microsuction was performed. Such a test would only be valid on ears clear of wax and dirt. But how do you do that when the ears are compromised with wax? They would need to use as reference a hearing test made before the wax buildup, which may have been made years or decades earlier. It's a chicken and egg situation.

They can claim that after the microsuction the hearing is better, which in my case it is better, and probably for others too, as the ear was badly blocked. But possibly worse, and permanently worse compared to that ear when clear of wax and before the microsuction.

In my case, the last time my hearing was tested was 8 years ago as a requirement for a job in audio recording. That test found my hearing in both ears satisfactory. Apart from probably some losses due to ageing over that 8 year period, even without a new test I am pretty sure that my left ear is now much worse than the right. The left ear was always my better ear - but not by a lot. Now it is definitely my worse ear. So in my case the right ear is a reference from which to compare the loss in left after microsuction of the left.

Without a valid baseline test of our hearing - with clear ears - and before the microsuction - I don't see how anyone can make any claims as to microsuction's safety re hearing loss.

Also I noticed claims that there is no research showing damage to hearing after microsuction. That of course can be used as an "argument from silence". What seems needed is solid research results showing no damage, not absence of research showing damage. There is a big difference.

Tim

 

Hi Tim, can you link to the paper you are referring to? I think I did see a few papers is critical of this procedure.

 

Thanks. I think this is the one.

https://onlinelibrary.wiley.com/doi/full/10.1111/j.1749-4486.2008.01841.x

The statement that they found no changes in hearing thresholds after the microsuction is unclear. In my case, my hearing was subjectively better because the wax was now removed, so you would hope it was better, not worse.

They seem to be saying that they were allowing for the improved hearing due to wax removal, but they didn't actually say it. I don't have access to the full paper. In a proper scientific test, the only variable is the one under test, in this case the microsuction. All other factors need to be controlled for.

So when they stated they found no evidence of changed thresholds after microsuction, I think the question to ask is "compared to what?"