Sleep Apnea, ObstructivesTONOSNCT07580170
Randomized Clinical Trial for Tonsil Surgery in Adults With Obstructive Sleep Apnea and Enlarged Tonsils
A study testing Tonsillectomy and Tonsillotomy in people with Sleep Apnea, Obstructives and Tonsil Hypertrophy, run by Turku University Hospital at 4 sites in Finland.
Trial summary
The aim is to investigate whether the tissue-preserving tonsil surgery technique is as effective as complete tonsil removal in the treatment of obstructive sleep apnea. The primary outcome measure is the change in the apnea-hypopnea index (AHI) before surgery and at 4-6, 24, and 60 months after surgery. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Sleep Apnea, Obstructives, Tonsil Hypertrophy
- What is being tested?
- Tonsillectomy and Tonsillotomy
- Type of treatment
- Pill or oral medicine, Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 132 participants
- Where
- 4 sitesFinland
- Study dates
- 1 Oct 2026to 1 Jan 2036
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- BMI < 35
- Tonsil size 2 - 4
- Otherwise healthy patient fit for tonsil surgery
- Apnea-hypopnea index > 15
- Obstructive sleep apnea symptoms
Who cannot join
- Pathological hemostasis or use of anticoagulation
- Craniofacial deformities
- Neurological condition with muscular hypotonia
- Other surgical treatment for OSA
Trial locations and contacts
4 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Finland4 sites
Helsinki University Hospital
Helsinki
Johanna Ruohoalho, MD, PhD, +35894711, firstname.lastname@hus.fi
Vanhapiha Nelli, MD
Oulu University Hospital
Oulu
Aleksi Laajala, MD, +35886699500, firstname.lastname@oulu.fi
Alakärppä Antti, MD, PhD
Tampere University Hospital
Tampere
Saara Markkanen, MD, PhD, +3583311611, firstname.lastname@pirha.fi
Saara Lesonen, MD
Turku University Hospital
Turku
Henrik M Sjöblom, MD, +35823130000, hmsjob@utu.fi
Jenny Knubb, MD, +35823130000
About this study
Official title: Multicenter, National, Randomized, Patient-Blinded, Parallel Group, Non-Inferiority Trial To Compare Tonsillotomy Versus Extracapsular Tonsillectomy in Adults With Obstructive Sleep Apnea and Tonsil Hypertrophy: The TONOS Trial.
The aim is to investigate whether the tissue-preserving tonsil surgery technique is as effective as complete tonsil removal in the treatment of obstructive sleep apnea. The primary outcome measure is the change in the apnea-hypopnea index (AHI) before surgery and at 4-6, 24, and 60 months after surgery.
Read the detailed description
Adult reviews suggest tonsillotomy (TT) reduces morbidity compared to tonsillectomy (TE). In pediatric populations, the effectiveness of partial tonsil surgery for sleep apnea (OSA) is well-documented. It remains unclear if TT is non-inferior to TE in adults in the treatment of OSA. This study compares TE with TT in adults using change in apnea-hypopnea index as the primary endpoint.
The hypothesis is that TT is non-inferior compared to TE in treating patients with moderate or severe OSA and grade 2 to 4 tonsil size.
Participants are blinded to the allocated intervention with an allocation ratio 1:1. Participants will be recruited from patients referred to an outpatient hospital clinic. The trial will be carried out in four tertiary hospitals in Finland.
- Conditions
- Sleep Apnea, Obstructives, Tonsil Hypertrophy
- Being tested
- Tonsillectomy, Tonsillotomy
- Keywords
- sleep apnea, tonsillectomy, tonsillotomy, intracapsular tonsillectomy, adults, tonsil hypertrophy
- Medical subject headings
- Sleep Apnea Syndromes
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
TonsillectomyProcedure or surgery
TE will be performed by dissection in the peritonsillar plane. Parts of the upper and lateral palatal mucosal arches will be incised, and an extracapsular dissection for complete tonsil excision will be performed.
TonsillotomyProcedure or surgery
TT will be performed by removing approximately 60 - 90% of the tonsillar tissue, leaving a rim of tonsillar tissue on the tonsillar fossae. The tonsil capsule will not be breached.
| Study group | Role | What they receive |
|---|---|---|
| Tonsillectomy | Active comparator | TE will be performed by dissection in the peritonsillar plane. Parts of the upper and lateral palatal mucosal arches will be incised, and an extracapsular dissection for complete tonsil excision will be performed.
The surgical instrumentation (eg. cold steel, monopolar diathermy with a pen electrode, bipolar scissors, coblation technique or a microdebrider) is selected by the surgeon. Receives: Procedure: Tonsillectomy |
| Tonsillotomy | Active comparator | TT will be performed by removing approximately 60 - 90% of the tonsillar tissue, leaving a rim of tonsillar tissue on the tonsillar fossae. The tonsil capsule will not be breached.
The surgical instrumentation (eg. cold steel, monopolar diathermy with a pen electrode, bipolar scissors, coblation technique or a microdebrider) is selected by the surgeon. Receives: Procedure: Tonsillotomy |
What is being measured
The primary outcome is the main question the study is designed to answer.
Changes in AHI at baseline and after surgery
The primary outcome is changes in AHI measured with home sleep study
Measured: baseline, 4-6, 24 and 60 months after surgery.
Secondary outcomes (5)
Daytime sleepiness
Measured with Epworth Sleepiness Scale (ESS) questionnaire (patient-reported). Points 0-18, higher is worse.
Measured: Baseline and 6, 12, 24 and 60 months after surgery
Changes in insomnia symptoms
Measured with Insomnia Severity Index (ISI) questionnaire, points range 0-28, higher is worse.
Measured: Baseline and 6, 12, 24 and 60 months after surgery
Surgical success rate
Defined according to Sher's criteria: a reduction in AHI of >50% and a total AHI of <20 after surgery
Measured: Baseline and 6, 12, 24 and 60 months after surgery
Surgical cure rate
Defined as a total AHI of <5 after surgery
Measured: Baseline and 6, 12, 24 and 60 months after surgery
Changes in nocturnal desaturation
Changes in nocturnal desaturation measured with oxygen saturation (SaO2) mean, min, and SpO2 <90% (T90) and ODI3, measured with home sleep study
Measured: Before surgery and 4-6, 24 and 60 months after surgery
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 May 2026
- Study start1 Oct 2026 (estimated)
- Primary completion1 Jan 2031 (estimated)
- Study completion1 Jan 2036 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Sleep Apnea, ObstructivesStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Tonsil surgery is performed while patient is under general anesthesia by experienced otorhinolaryngologist who are familiar with both techniques (a minimum of 20 procedures performed using each technique). TT will be performed by removing approximately 60 - 90% of the tonsillar tissue, leaving a rim of tonsillar tissue on the tonsillar fossae. The tonsil capsule will not be breached. TE will be performed by dissection in the peritonsillar plane. Parts of the upper and lateral palatal mucosal arches will be incised, and an extracapsular dissection for complete tonsil excision will be performed. The surgical instrumentation (eg. cold steel, monopolar diathermy with a pen electrode, bipolar scissors, coblation technique or a microdebrider) is selected by the surgeon.
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 132 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Turku University Hospital
- Sponsor type
- Other government
- Collaborators
- Tampere University Hospital, Oulu University Hospital, Helsinki University Central Hospital
- Responsible party
- Principal investigator, Jaakko Piitulainen, Turku University Hospital
- Investigators
- Jaakko M Piitulainen, MD, PhD, Study director, Turku University HospitalHenrik Sjöblom, MD, Principal investigator, Turku University HospitalJenny Knubb, MD, Principal investigator, Turku University Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07580170
- Sponsor's protocol ID
- VARHA/28047/13.02.02/2025
- Acronym
- TONOS
- Status last verified
- May 2026
- First submitted
- 27 Mar 2026
- Last updated
- 3 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Data dictionary describing the variables.
Study at a glance
From the registry record, last updated by the sponsor on 3 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Multicenter, National, Randomized, Patient-Blinded, Parallel Group, Non-Inferiority Trial To Compare Tonsillotomy Versus Extracapsular Tonsillectomy in Adults With Obstructive Sleep Apnea and Tonsil Hypertrophy: The TONOS Trial.
- ClinicalTrials.gov ID
- NCT07580170
- Acronym / sponsor ID
- TONOS / VARHA/28047/13.02.02/2025
- Conditions
- Sleep Apnea, Obstructives, Tonsil Hypertrophy
- Keywords
- sleep apnea, tonsillectomy, tonsillotomy, intracapsular tonsillectomy, adults, tonsil hypertrophy
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 132 participants (estimated)
- Lead sponsor
- Turku University HospitalOther government
- Collaborators
- Tampere University Hospital, Oulu University Hospital, Helsinki University Central Hospital
- Study start
- 1 Oct 2026 (estimated)
- Primary completion
- 1 Jan 2031 (estimated)
- Study completion
- 1 Jan 2036 (estimated)
- First posted
- 12 May 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The aim is to investigate whether the tissue-preserving tonsil surgery technique is as effective as complete tonsil removal in the treatment of obstructive sleep apnea. The primary outcome measure is the change in the apnea-hypopnea index (AHI) before surgery and at 4-6, 24, and 60 months after surgery.
Detailed description
Adult reviews suggest tonsillotomy (TT) reduces morbidity compared to tonsillectomy (TE). In pediatric populations, the effectiveness of partial tonsil surgery for sleep apnea (OSA) is well-documented. It remains unclear if TT is non-inferior to TE in adults in the treatment of OSA. This study compares TE with TT in adults using change in apnea-hypopnea index as the primary endpoint.
The hypothesis is that TT is non-inferior compared to TE in treating patients with moderate or severe OSA and grade 2 to 4 tonsil size.
Participants are blinded to the allocated intervention with an allocation ratio 1:1. Participants will be recruited from patients referred to an outpatient hospital clinic. The trial will be carried out in four tertiary hospitals in Finland.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- Tonsil surgery is performed while patient is under general anesthesia by experienced otorhinolaryngologist who are familiar with both techniques (a minimum of 20 procedures performed using each technique). TT will be performed by removing approximately 60 - 90% of the tonsillar tissue, leaving a rim of tonsillar tissue on the tonsillar fossae. The tonsil capsule will not be breached. TE will be performed by dissection in the peritonsillar plane. Parts of the upper and lateral palatal mucosal arches will be incised, and an extracapsular dissection for complete tonsil excision will be performed. The surgical instrumentation (eg. cold steel, monopolar diathermy with a pen electrode, bipolar scissors, coblation technique or a microdebrider) is selected by the surgeon.
| Arm | Type | Receives |
|---|---|---|
| Tonsillectomy | Active comparator | Procedure: TonsillectomyTE will be performed by dissection in the peritonsillar plane. Parts of the upper and lateral palatal mucosal arches will be incised, and an extracapsular dissection for complete tonsil excision will be performed. The surgical instrumentation (eg. cold steel, monopolar diathermy with a pen electrode, bipolar scissors, coblation technique or a microdebrider) is selected by the surgeon. |
| Tonsillotomy | Active comparator | Procedure: TonsillotomyTT will be performed by removing approximately 60 - 90% of the tonsillar tissue, leaving a rim of tonsillar tissue on the tonsillar fossae. The tonsil capsule will not be breached. The surgical instrumentation (eg. cold steel, monopolar diathermy with a pen electrode, bipolar scissors, coblation technique or a microdebrider) is selected by the surgeon. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- BMI < 35
- Tonsil size 2 - 4
- Otherwise healthy patient fit for tonsil surgery
- Apnea-hypopnea index > 15
- Obstructive sleep apnea symptoms
Key exclusion criteria (4 listed)
- Pathological hemostasis or use of anticoagulation
- Craniofacial deformities
- Neurological condition with muscular hypotonia
- Other surgical treatment for OSA
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| TonsillectomyTE will be performed by dissection in the peritonsillar plane. Parts of the upper and lateral palatal mucosal arches will be incised, and an extracapsular dissection for complete tonsil excision will be performed. | Procedure or surgery | Tonsillectomy |
| TonsillotomyTT will be performed by removing approximately 60 - 90% of the tonsillar tissue, leaving a rim of tonsillar tissue on the tonsillar fossae. The tonsil capsule will not be breached. | Procedure or surgery | Tonsillotomy |
Primary outcome
Changes in AHI at baseline and after surgery
Time frame: baseline, 4-6, 24 and 60 months after surgery.
The primary outcome is changes in AHI measured with home sleep study
5 secondary outcomes
Daytime sleepiness
Time frame: Baseline and 6, 12, 24 and 60 months after surgery
Changes in insomnia symptoms
Time frame: Baseline and 6, 12, 24 and 60 months after surgery
Surgical success rate
Time frame: Baseline and 6, 12, 24 and 60 months after surgery
Surgical cure rate
Time frame: Baseline and 6, 12, 24 and 60 months after surgery
Changes in nocturnal desaturation
Time frame: Before surgery and 4-6, 24 and 60 months after surgery
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Jun 2026.
- Individual participant dataSharing planned: Yes. Data dictionary describing the variables.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Jaakko M Piitulainen, MD, PhD study director
Turku University Hospital
Henrik Sjöblom, MD principal investigator
Turku University Hospital
Jenny Knubb, MD principal investigator
Turku University Hospital
4 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Tonsillectomy and Tonsillotomy in people with Sleep Apnea, Obstructives and Tonsil Hypertrophy, run by Turku University Hospital at 4 sites in Finland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 3 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 4 sites in Finland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Jaakko M Piitulainen, MD, PhD (+35823130000, jaakko.piitulainen@utu.fi), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Changes in AHI at baseline and after surgery (time frame: baseline, 4-6, 24 and 60 months after surgery.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Jun 2026; AzTrials last refreshed its copy on 30 Oct 2026.