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J Reconstr Microsurg 2015; 31(07): 500-507
DOI: 10.1055/s-0035-1554940
Original Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Advanced Microcirculatory Parameters of Lower Extremity Free Flaps during Dangling and Their Influencing Factors

Jonas Kolbenschlag
1   Department of Plastic Surgery, Burn Center, Sarcoma Center, BG University Hospital, Ruhr University, Bochum, Germany
,
Pascal Bredenbroeker
1   Department of Plastic Surgery, Burn Center, Sarcoma Center, BG University Hospital, Ruhr University, Bochum, Germany
,
Marcus Lehnhardt
1   Department of Plastic Surgery, Burn Center, Sarcoma Center, BG University Hospital, Ruhr University, Bochum, Germany
,
Adrien Daigeler
1   Department of Plastic Surgery, Burn Center, Sarcoma Center, BG University Hospital, Ruhr University, Bochum, Germany
,
Sebastian Fischer
2   Department of Hand, Plastic and Reconstructive Surgery, Burn Trauma Center, BG Trauma Center Ludwigshafen, University of Heidelberg, Ludwigshafen, Germany
,
Kamran Harati
1   Department of Plastic Surgery, Burn Center, Sarcoma Center, BG University Hospital, Ruhr University, Bochum, Germany
,
Andrej Ring
1   Department of Plastic Surgery, Burn Center, Sarcoma Center, BG University Hospital, Ruhr University, Bochum, Germany
,
Ole Goertz
1   Department of Plastic Surgery, Burn Center, Sarcoma Center, BG University Hospital, Ruhr University, Bochum, Germany
› Author Affiliations
Further Information

Publication History

19 February 2015

26 March 2015

Publication Date:
23 June 2015 (online)

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Abstract

Background Dangling of the leg to habituate a free flap to the lower extremity is common practice. However, little is known about the microcirculatory changes in free flaps and the influence of comorbidities.

Methods Tissue oxygen saturation (StO2) and hemoglobin content (tissue hemoglobin index [THI]) of 39 lower extremity free flaps was measured during dangling on postoperative days (PODs) 6 to 9. We assessed the maximal desaturation during dangling and re-elevation and the maximal increase in THI as well as the time required to reach a stable plateau during dangling, among others.

Results All parameters showed significant changes during dangling (desaturation during dangling: 0.23 ± 10.7 vs. − 4.66 ± 12.6%, p = 0.001 for POD 6 vs. 7; further desaturation after re-elevation: − 11.1 ± 7.4 versus − 14.5 ± 7.8%, p = 0.001 for POD 6 vs. 9; THI increase during dangling: from 3.4 ± 1.6 to 4.2 ± 1.8 AU, p = 0.008, time to THI plateau: 1.7 ± 1.2 vs. 2.5 ± 1.7 minutes, p = 0.004 for POD 6 vs. 7). Age, gender, and smoking did not influence the mentioned parameters. Nondiabetic patients showed a significant increase of baseline StO2, whereas diabetic patients did not (p = 0.009 vs. 0.11). For THI, both diabetic and hypertensive patients showed a lower increase in THI on the first day of dangling (p = 0.056; p = 0.009) and significantly lower baseline values on the last day (0.046 for both).

Conclusion Duration of dependency seems to have the greatest impact on microcirculation during dangling, although comorbidities may interfere with the adaptive processes. An earlier start of dangling could safely be applied in most patients. Special care needs to be taken in diabetic and hypertensive patients.

Keywords

free flap - dangling - lower extremity - reconstruction - microcirculation