{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,1]],"date-time":"2026-11-01T22:37:56Z","timestamp":1793572676854,"version":"4.5.0"},"reference-count":41,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2023,5,11]],"date-time":"2023-05-11T00:00:00Z","timestamp":1683763200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Life"],"abstract":"<jats:p>Background: Lower extremity free flap dangling protocols are still widely practiced, despite a paucity of evidence for their use. This pilot study investigates the use of tissue oximetry to provide further insight into the physiological effect of postoperative dangling in lower limb free flap transfer. Methods: Ten patients undergoing lower extremity free flap reconstruction were included in this study. Free flap tissue oxygen saturation (StO2) was continuously measured using non-invasive near-infrared spectroscopy. Measurements were performed on the free flap and contralateral limb during dangling from postoperative day (POD) 7 until 11, according to the local dangling protocol. Results: StO2 values measured in the free flap diminished to 70 \u00b1 13.7% during dangling. This minimum StO2 was reached significantly later, and correspondingly the area under the curve (AUC) was significantly larger on POD 11 compared to the start of the dangling protocol on POD 7, reflecting an improving free flap microvascular reactivity. The dangling slope was equal between the free flap and contralateral leg. The reperfusion slope was significantly flatter on POD 7 compared to the other PODs (p &lt; 0.001). Thereafter, no significant differences between PODs were observed. Patients with a history of smoking had significantly lower tissue oximetry values compared to non-smokers. Conclusions: The application of tissue oximetry during dangling provides further insight into the physiological effect (i.e., changes in microcirculatory function) of the free flap of the reconstructed lower extremity. This information could potentially be useful to either revise or disrupt the use of such dangling protocols.<\/jats:p>","DOI":"10.3390\/life13051158","type":"journal-article","created":{"date-parts":[[2023,5,11]],"date-time":"2023-05-11T01:37:09Z","timestamp":1683769029000},"page":"1158","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Tissue Oximetry Changes during Postoperative Dangling in Lower Extremity Free Flap Reconstruction: A Pilot Study"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4275-2804","authenticated-orcid":false,"given":"Anouk A. M. A.","family":"Lindelauf","sequence":"first","affiliation":[{"name":"Department of Cardiothoracic Surgery, Maastricht University Medical Center, 6202 AZ Maastricht, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5066-7909","authenticated-orcid":false,"given":"Joep A. F.","family":"van Rooij","sequence":"additional","affiliation":[{"name":"Department of Plastic, Reconstructive and Hand Surgery, Maastricht University Medical Center, 6202 AZ Maastricht, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Loes","family":"Hartveld","sequence":"additional","affiliation":[{"name":"Department of Plastic, Reconstructive and Hand Surgery, Maastricht University Medical Center, 6202 AZ Maastricht, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ren\u00e9 R. W. J.","family":"van der Hulst","sequence":"additional","affiliation":[{"name":"Department of Plastic, Reconstructive and Hand Surgery, Maastricht University Medical Center, 6202 AZ Maastricht, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Patrick W.","family":"Weerwind","sequence":"additional","affiliation":[{"name":"Department of Cardiothoracic Surgery, Maastricht University Medical Center, 6202 AZ Maastricht, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3730-2075","authenticated-orcid":false,"given":"Rutger M.","family":"Schols","sequence":"additional","affiliation":[{"name":"Department of Plastic, Reconstructive and Hand Surgery, Maastricht University Medical Center, 6202 AZ Maastricht, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,5,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2219","DOI":"10.1097\/00006534-200206000-00007","article-title":"Have we found an ideal soft-tissue flap? An experience with 672 anterolateral thigh flaps","volume":"109","author":"Wei","year":"2002","journal-title":"Plast. Reconstr. Surg."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"243","DOI":"10.1097\/00006534-197509000-00001","article-title":"The anatomy of several free flap donor sites","volume":"56","author":"Palmer","year":"1975","journal-title":"J. Plast. Reconstr. Surg."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1055\/s-0038-1667049","article-title":"Postoperative management of lower extremity free tissue transfer: A systematic review","volume":"35","author":"Soteropulos","year":"2019","journal-title":"J. Reconstruct. Microsurg."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"319","DOI":"10.1055\/s-0033-1363773","article-title":"Changes of oxygenation and hemoglobin-concentration in lower extremity free flaps during dangling","volume":"30","author":"Kolbenschlag","year":"2014","journal-title":"J. Reconstr. Microsurg."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"280","DOI":"10.1097\/SAP.0b013e3181579900","article-title":"A survey of microvascular protocols for lower extremity free tissue transfer II: Postoperative care","volume":"61","author":"Xipoleas","year":"2008","journal-title":"Ann. Plast. Surg."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1017","DOI":"10.1016\/j.bjps.2017.04.001","article-title":"Systematic review: Early versus late dangling after free flap reconstruction of the lower limb","volume":"70","author":"McGhee","year":"2017","journal-title":"J. Plast. Reconstr. Aesthet. Surg."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"601","DOI":"10.1055\/s-0030-1267384","article-title":"A survey of U.K. units and a suggested protocol for free flap reconstruction of the lower limb: Follow-up and management in the first postoperative week","volume":"26","author":"Greenwood","year":"2010","journal-title":"J. Reconstr. Microsurg."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/s13063-019-3665-0","article-title":"Is dangling of the lower leg after a free flap reconstruction necessary? Study protocol for a large multicenter randomized controlled study","volume":"20","author":"Krijgh","year":"2019","journal-title":"Trials"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"540","DOI":"10.1097\/SAP.0b013e31820909f9","article-title":"Three-year experience using near infrared spectroscopy tissue oximetry monitoring of free tissue transfers","volume":"66","author":"Steele","year":"2011","journal-title":"Ann. Plast. Surg."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"103","DOI":"10.1177\/1553350619862097","article-title":"Optimizing Indocyanine Green Fluorescence Angiography in Reconstructive Flap Surgery: A systematic Review and Ex Vivi Experiments","volume":"27","author":"Pruimboom","year":"2020","journal-title":"Surg. Innovat."},{"key":"ref_11","first-page":"1","article-title":"Early detection onset of flap failure using near infrared spectroscopy","volume":"29","author":"Ozkan","year":"2021","journal-title":"J. Plast. Surg. Hand Surg."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"267","DOI":"10.1007\/s00238-021-01873-7","article-title":"Exploring personalized postoperatibe non-invasive tissue oximetry in DIEP flap breast reconstuction","volume":"45","author":"Lindelauf","year":"2022","journal-title":"Eur. J. Plast. Surg."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"534","DOI":"10.1177\/1553350620942985","article-title":"Economic analysis of noninvasive tissue oximetry for postoperative monitoring of deep inferior epigastric perforator flap breast reconstruction: A review","volume":"27","author":"Lindelauf","year":"2020","journal-title":"Surg. Innovat."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"71","DOI":"10.1016\/j.bjps.2007.04.003","article-title":"Continuous postoperative monitoring of cutaneous free flaps using near infrared spectroscopy","volume":"61","author":"Repez","year":"2008","journal-title":"J. Plast. Reconstr. Aesthet. Surg."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"538","DOI":"10.1097\/SAP.0b013e3181a47ce8","article-title":"A new diagnostic algorithm for early prediction of vascular compromise in 208 microsurgical flaps using tissue oxygen saturation measurements","volume":"62","author":"Keller","year":"2009","journal-title":"Ann. Plast. Surg."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"268","DOI":"10.1002\/micr.30526","article-title":"Outcomes of free flap reconstructions with near-infrared spectroscopy (NIRS) monitoring: A systematic review","volume":"40","author":"Newton","year":"2020","journal-title":"Microsurgery"},{"key":"ref_17","first-page":"1264","article-title":"Non-invasive Infrared Monitoring of Cerebral and Myocardial Oxygen Sufficiency and Circulatory Parameters","volume":"198","author":"Jobsis","year":"1977","journal-title":"AAAS"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"i3","DOI":"10.1093\/bja\/aep299","article-title":"Near-infrared spectroscopy as an index of brain and tissue oxygenation","volume":"103","author":"Murkin","year":"2009","journal-title":"Br. J. Anaest."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"559","DOI":"10.1055\/s-0030-1263292","article-title":"New insight into an old paradigm: Wrapping and dangling with lower-extremity free flaps","volume":"26","author":"Ridgway","year":"2010","journal-title":"J. Reconstr. Microsurg."},{"key":"ref_20","first-page":"179","article-title":"Perfusion controlled mobilization after lower extremity free flaps-pushing the limits of time and intensity","volume":"33","author":"Dornseifer","year":"2017","journal-title":"J. Reconstr. Microsurg."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"165","DOI":"10.1007\/s12028-007-0010-3","article-title":"Bilateral near infrared spectroscopy in space-occupying middle cerebral artery stroke","volume":"6","author":"Damian","year":"2007","journal-title":"Neurocrit. Care"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1753","DOI":"10.1038\/sj.jid.5700329","article-title":"In Vivo Monitoring of Cutaneous Edema using Spectral Imaging in the Visible and Near Infrared","volume":"126","author":"Stamatas","year":"2006","journal-title":"J. Investig. Dermatol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1346","DOI":"10.1097\/SCS.0000000000000812","article-title":"Evaluation of foot perfusion after fibula flap surgery","volume":"25","author":"Shan","year":"2014","journal-title":"J. Craniofac. Surg."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1007\/s10877-013-9507-9","article-title":"Peripheral tissue oximetry: Comparing three commercial near-infrared spectroscopy oximeters on the forearm","volume":"28","author":"Hessel","year":"2014","journal-title":"J. Clin. Monit. Comput."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1007\/s10877-007-9105-9","article-title":"Near-infrared spectroscopy to monitor peripheral blood flow perfusion","volume":"22","author":"Harel","year":"2008","journal-title":"J. Clin. Monit. Comput."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"979","DOI":"10.1053\/j.jvca.2016.03.003","article-title":"Vascular occlusion test to dynamically assess microcirculation during normothermic pulsatile cardiopulmonary bypass","volume":"30","author":"Vranken","year":"2016","journal-title":"J. Cardiothorac. Vasc. Anesth."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1600","DOI":"10.1007\/s00134-008-1145-1","article-title":"Use of non-invasive NIRS during a vascular occlusion test to assess dynamic tissue O2 saturation response","volume":"34","author":"Gomez","year":"2008","journal-title":"Intensive Care Med."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1217","DOI":"10.1053\/j.jvca.2014.03.016","article-title":"A novel assessment of peripheral tissue microcirculatory vasoreactivity using vascular occlusion testing during cardiopulmonary bypass","volume":"28","author":"Smith","year":"2014","journal-title":"J. Cardiothorac. Vasc. Anesth."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1016\/0007-1226(95)90024-1","article-title":"Near infra-red spectroscopy: A non-invasive monitor of perfusion and oxygenation within the microcirculation of limbs and flaps","volume":"48","author":"Irwin","year":"1995","journal-title":"Br. J. Plast. Surg."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"e127","DOI":"10.1097\/GOX.0000000000000080","article-title":"Early mobilization after free-flap transfer to the lower extremities: Preferential use of flow-through anastomosis","volume":"2","author":"Miyamoto","year":"2014","journal-title":"Plast. Reconstr. Surg. Glob. Open"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1055\/s-0028-1090600","article-title":"A recommended protocol for the immediate postoperative care of lower extremity free-flap reconstructions","volume":"25","author":"Rohde","year":"2009","journal-title":"J. Reconstr. Microsurg."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"536","DOI":"10.1002\/micr.22476","article-title":"Flow-through anastomosis for both the artery and vein in leg free flap transfer","volume":"35","author":"Fujiki","year":"2015","journal-title":"Microsurgery"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1090","DOI":"10.1002\/hed.20639","article-title":"Predictors of morbidity following free flap reconstruction for cancer of the head and neck","volume":"29","author":"Clark","year":"2007","journal-title":"Head Neck"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"86","DOI":"10.1097\/00006534-199601000-00015","article-title":"The effect of cigarette smoking on the survival of free vascularized and pedicled epigastric flaps in the rat","volume":"97","author":"Hoegen","year":"1996","journal-title":"Plast. Reconstr. Surg."},{"key":"ref_35","first-page":"e79","article-title":"The impact of smoking on surgical complications after head and neck reconstructive surgery with free vascularised tissue flap: A systematic review and meta-analysis","volume":"59","author":"Garip","year":"2021","journal-title":"BJOMS"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"500","DOI":"10.1055\/s-0035-1554940","article-title":"Advanced microcirculatory parameters of lower extremity free flaps during dangling and their influencing factors","volume":"31","author":"Kolbenschlag","year":"2015","journal-title":"J. Reconstr. Microsurg."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"492","DOI":"10.1055\/s-0038-1639377","article-title":"Does cigarette smoking harm microsurgical free flap reconstruction?","volume":"34","author":"Ehrl","year":"2018","journal-title":"J. Reconstr. Microsurg."},{"key":"ref_38","first-page":"512","article-title":"Predicting risk factors that lead to free flap failure and vascular compromise: A single unit experience with 565 free tissue transfer","volume":"74","author":"Lese","year":"2021","journal-title":"JPRAS"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"535","DOI":"10.1186\/s13018-021-02686-x","article-title":"Factors affecting the outcome of lower extremity osteomyelitis treated with microvascular free flaps: An analysis of 65 patients","volume":"16","author":"Thai","year":"2021","journal-title":"J. Orthop Surg. Res."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"184","DOI":"10.3390\/diagnostics12010184","article-title":"Perioperative hyperspectral imaging to assess mastectomy skin flap and DIEP flap perfusion in immediate autologous breast reconstruction: A pilot study","volume":"12","author":"Pruimboom","year":"2022","journal-title":"Diagnostics"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"65","DOI":"10.3390\/life12010065","article-title":"Near-infrared spectroscopy (NIRS) versus hyperspectral imaging (HSI) to detect flap failure in reconstructive surgery: A systematic review","volume":"12","author":"Lindelauf","year":"2022","journal-title":"Life"}],"container-title":["Life"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-1729\/13\/5\/1158\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T19:32:38Z","timestamp":1760124758000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-1729\/13\/5\/1158"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,5,11]]},"references-count":41,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2023,5]]}},"alternative-id":["life13051158"],"URL":"https:\/\/doi.org\/10.3390\/life13051158","relation":{},"ISSN":["2075-1729"],"issn-type":[{"value":"2075-1729","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,5,11]]}}}