Abstract
Microvascular free tissue transfer is a routine procedure with high predictability and a low complication rate. However, compromised flap perfusion remains a challenge and there is no consensus regarding the appropriate flap salvage protocol. The purpose of this study was to identify techniques with implications for flap salvage procedures and to assess their efficacy. A systematic review of studies published in the literature between 1990 and 2015, with predefined inclusion and exclusion criteria, was performed. The data obtained were pooled and analyzed. A total of 39 studies qualified for data extraction. The overall level of evidence was low and the total number of reported cases was limited (330 flaps). Five studies involved control groups and supplied comparative data. Surgical anastomotic revision and thrombectomy are inevitable in every flap salvage protocol. Four techniques or combinations of these with positive effects on flap salvage success rates were identified: thrombectomy with a Fogarty catheter (six studies, 68 flaps), intraoperative use of thrombolytic drugs (16 studies, 184 flaps), placement of an arteriovenous fistula (five case reports, five flaps), and the postoperative application of medicinal leeches (11 studies, 73 flaps). Currently available data exploring flap salvage procedures are limited. None of the techniques presented yielded superior salvage outcomes.
Microvascular surgical procedures in reconstructive and trauma surgery have become safe and predictable in recent years, with reported long-term success rates of over 90%. Up until flap autonomization, the outcome of successful free tissue transfer depends on the integrity and patency of the microvascular anastomosis and pedicle. Despite advances in surgical techniques and perioperative intensive care, the postoperative course after microvascular tissue transfer remains a challenge due to postoperative surgery- and patient-related complications. As well as extravascular problems such as haematoma, infection, pedicle kinking, and oedema, intravascular processes such as vessel spasms, thrombosis formation, and arterial or venous insufficiency can threaten pedicle patency and lead to compromised perfusion or even flap failure. Close postoperative flap monitoring can reveal early signs of decreased perfusion, and re-exploration of the anastomosis can be initiated. There is evidence that immediate flap revision at the first sign of diminished perfusion increases the flap salvage rate. Although most flap perfusion problems occur within the first day after surgery, delayed flap failure has been reported and the success rate of salvage attempts decreases with time. As the overall number of microvascular flap failures is low, studies exploring the efficacy of different salvage procedures, and especially late salvage procedures, are rare.
Immediate re-exploration of the anastomotic site remains the gold standard treatment in cases of early and delayed compromised flap perfusion. To improve salvage rates, different surgical and non-surgical approaches for securing the re-establishment of pedicle patency have been discussed. However, late flap complications in particular remain a challenge and pose a high risk for eventual flap loss.
The purpose of this systematic literature review was to identify surgical and non-surgical techniques that are recommended in salvage algorithms for compromised microvascular flaps in addition to anastomotic revision. Specific aims were (1) to identify the applicable literature, (2) to extract the relevant data, (3) to analyze the information gained statistically, and (4) to assess the efficacy of the techniques found.
Materials and methods
Search strategy
To address the research question, a systematic review of the literature in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement was performed. The online databases PubMed, Scopus, Google Scholar, and Web of Science were searched for scientific literature published in the English language between 1990 and 2015 using the following search terms: “free flap failure therapy” OR “free flap failure thrombolysis” OR “free flap failure salvage” OR “free flap failure rescue” OR “free flap salvage” OR “free flap rescue” OR “free flap complication rescue” OR “free flap complication salvage”.
Inclusion and exclusion criteria
To qualify for data extraction, the articles identified had to meet the following predefined inclusion criteria: human studies; studies reporting microvascular free flap salvage procedures; explicit description of flap salvage protocol; incidence of free flap complications after the patient had left the operating room; compromised perfusion as the reason for impending flap failure; studies published in the English language.
The following exclusion criteria were applied: animal studies; salvage procedures for microvascular complications in replantation surgery; intraoperative free flap complications; surgical reintervention at the anastomotic site for reasons other than vascular free flap compromise.
Due to the paucity of published data, all study types were considered, including case series and single case reports. Review articles were excluded.
Data extraction, study variables, and analysis
Eligible studies and case reports were screened for the following data: author, year of publication, type of study, number of flaps, type of flap, type of perfusion problem (arterial/venous congestion or combinations), intervention, number of flaps lost, comparative data (if applicable), special complications. The data obtained were tabulated and analyzed descriptively. The primary predictor variable was the intervention. The primary outcome variable was the flap salvage rate. All statistical analyses were performed using SPSS for Windows version 23.0 software (IBM Corp., Armonk, NY, USA). The quality assessment (level of Evidence, LOE) of the selected studies was performed as recommended by the Oxford Centre for Evidence-Based Medicine (2011).
Results
The systematic literature review yielded 39 studies and case reports that met the inclusion criteria and qualified for data extraction. A flowchart of the search process is provided in Fig. 1 . The heterogeneity between studies was high. In general, the LOE of the literature reporting procedures with possible implications for salvage rates of microvascular flaps with compromised perfusion was limited (LOE: 17 level V, 17 level IV, 5 level III). All studies were retrospective in design and there were no randomized controlled trials. In the majority of the studies examined ( n = 36), surgical revision of the anastomotic sites with or without irrigation (heparin, saline, lidocaine, papaverine) was performed as a major step of the salvage procedure. Only three studies discussed interventional, catheter-directed thrombolysis as a viable alternative to surgical re-exploration of the microvascular anastomoses.
With respect to the exact flap perfusion issue, four additional techniques with possibly positive effects on salvage rates of failing microvascular flaps due to pedicle thrombosis or insufficiency were reported in the literature: (1) the postoperative use of medicinal leeches, (2) the adjunctive administration of thrombolytic drugs in salvage procedures, (3) thrombectomy using a Fogarty catheter, and (4) the use of an arteriovenous fistula; combinations of these were also used.
Medicinal leeches
This systematic review identified 11 studies exploring the effects of the application of medicinal leeches in flap salvage procedures ( Table 1 ). The indication for medicinal leech application was exclusively venous congestion. The cumulative assessment of all of these studies showed that 10 out of 73 flaps treated with medicinal leeches after surgical revision eventually failed (salvage rate 86%). Haemorrhage and infection were mentioned as considerable complications of medicinal leech therapy. There were no control groups examining salvage procedures without medicinal leeches. Therefore, the definitive efficacy of medicinal leech use in flap salvage procedures could not be determined.
| Authors, year | Level of evidence | Number of flaps | Type of problem | Type of flap | Number of flaps lost | Complications | Average time until inosculation (days) | Blood transfusion, average units needed |
|---|---|---|---|---|---|---|---|---|
| Gilhooly et al., 1993 | V | 1 | Venous thrombosis | N/A | 0 | None | 4 | 0 |
| Soucacos et al., 1994 | IV | 20 | Venous thrombosis | 18 fasciocutaneous 2 myocutaneous |
3 fasciocutaneous 0 myocutaneous |
Haemorrhage, infection, blood transfusions required | 5 | 14 |
| Haycox et al., 1995 | V | 1 | Venous thrombosis | N/A | 0 | None | 22 | N/A |
| Chepeha et al., 2002 | IV | 8 | Venous thrombosis | N/A | 0 | Haemorrhage | 6.6 | 13 |
| Ribuffo et al., 2004 | V | 1 | Venous thrombosis | N/A | 0 | Haemorrhage | 5 | N/A |
| Zhao et al., 2009 | IV | 5 | Venous thrombosis | 3 fasciocutaneous 2 myocutaneous |
0 fasciocutaneous 0 myocutaneous |
None | 5 | 6.6 |
| Whitaker et al., 2011 | IV | 4 | Venous thrombosis | 4 myocutaneous | 0 | Haemorrhage, infection, blood transfusions required | 5.6 | 3 |
| Koch et al., 2012 | IV | 5 | 3 venous thrombosis 2 venous + arterial thrombosis |
5 fasciocutaneous | 0 | Haemorrhage, blood transfusions required | 9 | 13.5 |
| Nguyen et al., 2012 | IV | 13 | Venous thrombosis | 3 fasciocutaneous 10 myocutaneous |
1 fasciocutaneous 3 myocutaneous |
None | 5.4 | 3.5 |
| Pannucci et al., 2014 | IV | 4 | Venous thrombosis | 4 myocutaneous | 3 myocutaneous | Haemorrhage | 4 | 5 |
| Kucur et al., 2015 | IV | 11 | Not specified | N/A | 0 | N/A | N/A | N/A |
| Total | 73 | 10 | ||||||
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