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Reconstructive SurgeryFLARENCT07887256

Flap Assessment With Regional Oximetry for Early Detection of Compromise in Free Flap Reconstructive Surgery - FLARE Study

An observational study of Reconstructive Surgery and Flap Monitoring, run by Leiden University Medical Center at 3 sites in Netherlands.

Not yet recruiting

Opening soon. The study is approved but enrolment has not started yet. Sites may already take enquiries.

Sites and contacts
Official record
Search all trials

Trial summary

After some operations in which tissue is removed, it is necessary to repair the defect with a piece of tissue from another location in the body. This is called a microsurgically transplanted tissue flap (or tissue flap, for short). It is important that, after an operation, enough blood flows to the relocated tissue. Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Reconstructive Surgery, Flap Monitoring
What is being tested?
Elective free flap surgery and INVOS monitoring
How many people
100 participants
Where
3 sitesNetherlands
Study dates
Dec 2026to Dec 2028
Phase
Observational
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 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Study population: Patients scheduled for elective free flap reconstructive surgery

Who may be able to join

  • Patients 18 years or older who are schedulded for elective free flap reconstructive surgery

Who cannot join

  • Severe cardiac comorbidities (NYHA heart failure >2)
  • Severe pulmonary comorbidities (MET<4)
  • Oxygen saturation level < 90% without supplemental oxygen during preop visit
  • Any contraindications for INVOStm monitoring
  • Inability or refusal to complete informed consent form
  • Absence of an adequate site for safe and reliable INVOS™ sensor placement on or near the free flap, or for placement of the reference sensor, as determined by the treating plastic surgeon

Trial locations and contacts

3 sites in 1 country. Contact the study team or a site near you to ask about taking part.

Martijn Boon, MD, PhD contact

0031 71 526 2301

m.boon@lumc.nl

Netherlands3 sites

  • Leiden University Medical Centre

    Leiden, South Holland, 2333 ZA

    Martijn Boon, MD, PhD, 0031 71 526 91 11, m.boon@lumc.nl

    Hendrik J.F. Helmerhorst, MD, PhD

  • Haaglanden Medisch Centrum, locatie Anthoniushove

    Leidschendam, South Holland, 2262 BA

    Yuen M. Cheung, MD, PhD, 0031 88 979 79 00, y.cheung@haaglandenmc.nl

    Yuen M. Cheung, MD, PhD

  • HagaZiekenhuis

    The Hague, South Holland, 2545 AA

    Mandana Rad, MD, PhD, 0031 70 210 0000, m.rad@hagaziekenhuis.nl

    Mandana Rad, MD, PhD

Other trials in Netherlands

About this study

After some operations in which tissue is removed, it is necessary to repair the defect with a piece of tissue from another location in the body. This is called a microsurgically transplanted tissue flap (or tissue flap, for short). It is important that, after an operation, enough blood flows to the relocated tissue. In this study, we want to investigate whether, after the operation, measuring oxygen in the tissue flap with the INVOS 7100c device helps detect blood flow problems earlier. In the future, this could help doctors intervene more quickly, thereby reducing the risk of complications.

Read the detailed description

Reconstruction of defects using free flaps has become increasingly popular. However, vascular compromise is a potential postoperative complication leading to ischemia of (parts of the) flap. Early detection of perfusion problems is pivotal and directly correlated with increased flap salvage. Currently, detection of flap ischemia relies on frequent postoperative clinical inspection of the flap and the assessment of doppler signal of the (perforator) artery of the flap. These inspections are labor intensive and potentially suboptimal as these inspections are done in one- to four-hour intervals. Near infrared tissue oximetry using INVOStm monitoring technique allows for continuous monitoring of the flap, which may improve detection of flap ischemia and reduce the work load for health care personnel. Previous studies using NIRS for free flap monitoring have reported promising results, but available evidence is limited by differences in NIRS devices, algorithms, flap types, monitoring protocols, sensor placement, definitions of vascular compromise and proposed alarm thresholds. In addition, practical aspects of prolonged postoperative monitoring on a recovery unit or ward, including sensor adherence, signal quality, missing or uninterpretable data, patient mobility and patient experience, have not been sufficiently studied.

Main objective: To assess the feasibility of postoperative INVOS tissue oximetry monitoring after free-flap reconstructive surgery.

Secondary objectives:

To descriptively evaluate clinical outcomes after free-flap reconstructive surgery, including flap-at-risk episodes, surgical re-exploration, flap failure, postoperative complications and patient-reported experience with INVOS™ monitoring.

Study design: Multi-center, observational cohort study Study population: adult patients scheduled for elective free flap reconstructive surgery Main study endpoints: Successful maintenance of continuous monitoring, proportion of missing or uninterpretable StO₂ data, and sensor displacement or detachment requiring inter-vention or replacement. Nature and extent of the burden and risks associated with participation, benefit and group relatedness: Participants will receive perioperative surgical and anesthetic care as usual. At the end of surgery, INVOStm stickers will be placed at the free-flap by the surgeon. In addition, an INVOStm sticker will be placed at the femoral muscle which will serve as so-matic reference. Postoperative flap controls will follow routine protocol; no decisions will be made based on INVOStm readings.

Being tested
Elective free flap surgery, INVOS monitoring
Keywords
DIEP, INVOS, Reconstructive surgery, Free flap surgery, Near-infrared spectroscopy, Flap monitoring

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Elective free flap surgeryProcedure or surgery

    Reconstruction using deep inferior epigastric perforator (DIEP) flap. Participants will receive standard surgical, anaesthetic and postoperative care according to local practice.

  • INVOS monitoringDevice

    The INVOS system (In Vivo Optical Spectroscopy). INVOS™ sensors will be applied to the free flap and to a femoral reference site for postoperative tissue oximetry monitoring. The INVOS™ monitor readings will not be visible to caregivers, alarms will be muted, and INVOS™ measurements will not be used for clinical decision-making during this study. Clinical assessment and Doppler monitoring will remain leading for all decisions regarding flap viability.

Study groups in NCT07887256
Study groupRoleWhat they receive
Primary cohortAdult patients scheduled for elective free flap reconstructive surgery.
Receives: Procedure: Elective free flap surgery; Device: INVOS monitoring

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Proportion successfully maintained monitor

    The proportion of patients (%) in whom continuous tissue oximetry monitoring was successfully maintained for the entire postoperative period.

    Measured: From day of surgery (day 0) until day 3 postoperative

Secondary outcomes (9)

  1. Surgical re-exploration

    Surgical re-exploration performed because of suspected vascular compromise of the free flap. Yes/no.

    Measured: From day of surgery (day 0) until day 3 postoperative

  2. Flap failure

    Flap failure. Yes/no.

    Measured: From day of surgery (day 0) until day 3 postoperative

  3. Flap risk score

    0= no risk parameters present 6= all risk parameters present. Risk parameters are: color, consistency, capillary refill, temperature, doppler signal, clinical suspiscion. Parameters score 0 if the parameter is clinically judged to be normal/optimal and 1 if parameter is clinically judged to be suboptimal

    Measured: From day of surgery (day 0) until day 3 posteroperative

  4. Postoperative complications

    According to Clavien-Dindo scale

    Grade I Any deviation from the normal postoperative course without the need for pharmacological treatment or surgical, endoscopic and radiological interventions. Allowed therapeutic regimens are: drugs as antiemetics, antipyretics, analgetics, diuretics and electrolytes and physiotherapy. This grade also includes wound infections opened at the bedside.

    Grade II Requiring pharmacological treatment with drugs other than such allowed for grade I complications. Blood transfusionsand total parenteral nutritionare also included.

    Grade III Requiring surgical, endoscopic or radiological intervention

    • IIIa Intervention not under general anesthesia
    • IIIb Intervention under general anesthesia

    Grade IV Life-threatening complication (including CNS complications)* requiring IC/ICU-management

    • IVa single organ dysfunction (including dialysis)
    • IVb multiorgandysfunction

    Grade V Death of a patient

    Measured: From day of surgery (day 0) until day 3 posteroperative

  5. INVOS risk triggers: absolute drop of StO₂

    Number of absolute drops of StO₂ < 60%.

    Measured: From start of INVOS measurements (day 0) until day 3 postoperative

  6. INVOS risk triggers: relative drop StO₂

    Number of relative drops of StO₂ ≥20% decrease from baseline sustained ≥30 minutes.

    Measured: From start of INVOS measurements (day 0) until day 3 postoperative

  7. INVOS risk triggers: flap-to-reference ratio

    Flap-to-reference ratio of <0.75. Yes/no

    Measured: From start of INVOS measurements (day 0) until day 3 postoperative

  8. Incidence sensor displacement or detachment

    The incidence of mechanical sensor displacement or complete detachment requiring clinical intervention or sensor replacement within the first 48 hours postoperatively.

    Measured: From day of surgery (day 0) until day 3 posteroperative

  9. Cumulative duration missing StO2 data

    The cumulative duration of missing or uninterpretable tissue oxygen saturation (StO₂) data due to sensor detachment, signal artifacts, or hardware failure, expressed as a percentage (%) of the total monitoring time.

    Measured: From start INVOS measurement (day 0) until day 3 postoperative

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted21 Oct 2026
  2. Study startDec 2026 (estimated)
  3. Primary completionDec 2028 (estimated)
  4. Study completionDec 2028 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Observational
Observational model
Cohort
Time perspective
Prospective
Enrolment
100 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07887256
Sponsor's protocol ID
NL-010821
Other IDs
P26.023
Acronym
FLARE
Status last verified
Oct 2026
First submitted
23 Sep 2026
Last updated
21 Oct 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
Yes
Individual data sharing
Undecided

Publications

  • Lindelauf AAMA, Vranken NPA, Rutjens VGH, Schols RM, Heijmans JH, Weerwind PW, van der Hulst RRWJ. Economic Analysis of Noninvasive Tissue Oximetry for Postoperative Monitoring of Deep Inferior Epigastric Perforator Flap Breast Reconstruction: A Review. Surg Innov. 2020 Oct;27(5):534-542. doi: 10.1177/1553350620942985. Epub 2020 Jul 23.

    PubMed 32701027

  • Whitaker IS, Pratt GF, Rozen WM, Cairns SA, Barrett MD, Hiew LY, Cooper MA, Leaper DJ. Near infrared spectroscopy for monitoring flap viability following breast reconstruction. J Reconstr Microsurg. 2012 Mar;28(3):149-54. doi: 10.1055/s-0031-1296030. Epub 2011 Nov 30.

    PubMed 22131106

  • Salgarello M, Pagliara D, Rossi M, Visconti G, Barone-Adesi L. Postoperative Monitoring of Free DIEP Flap in Breast Reconstruction with Near-Infrared Spectroscopy: Variables Affecting the Regional Oxygen Saturation. J Reconstr Microsurg. 2018 Jul;34(6):383-388. doi: 10.1055/s-0038-1636527. Epub 2018 Apr 19.

    PubMed 29672776

  • Kagaya Y, Miyamoto S. A systematic review of near-infrared spectroscopy in flap monitoring: Current basic and clinical evidence and prospects. J Plast Reconstr Aesthet Surg. 2018 Feb;71(2):246-257. doi: 10.1016/j.bjps.2017.10.020. Epub 2017 Nov 22.

    PubMed 29175135

  • Kumbasar DE, Hagiga A, Dawood O, Berner JE, Blackburn A. Monitoring Breast Reconstruction Flaps Using Near-Infrared Spectroscopy Tissue Oximetry. Plast Surg Nurs. 2021 Apr-Jun 01;41(2):108-111. doi: 10.1097/PSN.0000000000000380.

    PubMed 34033637

  • Keller A. A new diagnostic algorithm for early prediction of vascular compromise in 208 microsurgical flaps using tissue oxygen saturation measurements. Ann Plast Surg. 2009 May;62(5):538-43. doi: 10.1097/SAP.0b013e3181a47ce8.

    PubMed 19387157

Questions about this trial

What is this clinical trial studying?

An observational study of Reconstructive Surgery and Flap Monitoring, run by Leiden University Medical Center at 3 sites in Netherlands.

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 1 inclusion and 6 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 21 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 3 sites in Netherlands. 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 Martijn Boon, MD, PhD (0031 71 526 2301, m.boon@lumc.nl), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Proportion successfully maintained monitor (time frame: From day of surgery (day 0) until day 3 postoperative). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07887256, which also lists 6 linked publications.

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 21 Oct 2026.

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