Risk factors for free flap failure: a retrospective analysis of 881 free flaps for head and neck defect reconstruction

Abstract

The aim of this study was to identify the risk factors for free flap failure after head and neck reconstructive surgery. The data of 881 consecutive patients who underwent free flap surgery at the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, between January 2013 and November 2016, were reviewed retrospectively. All surgeries were performed by a single head and neck surgical team. Patient demographic and surgical data that may have an influence on free flap outcomes were recorded. The χ 2 test and multivariate logistic regression analysis were used to identify relevant risk factors. In total, 881 free tissue transfer surgeries were included in this study. Free flap failure occurred in 26 of 881 flaps (2.9%). A history of irradiation (odds ratio 0.205, 95% confidence interval 0.07–0.56; P = 0.002) was a statistically significant risk factor for free flap failure. Age, diabetes mellitus, history of previous neck surgery to the anastomosis side, donor site, choice of recipient vein, use of a coupler device, and postoperative anticoagulation were not associated with free flap outcomes. Thus, it is concluded that when performing head and neck reconstructive surgery, special attention should be paid to patients who have previously undergone irradiation.

With improvements in microsurgical techniques and instruments, free tissue transfer has become the most reliable method of treating head and neck defects. Although free flap transfers have high success rates (ranging from 90% to 99%), flap loss, which can be devastating for both the patient and surgeon, remains a possibility . A better understanding of the causes of flap loss is necessary to avoid this disastrous outcome.

Numerous possible risk factors have been reported for flap loss, including age, sex, hypertension, diabetes mellitus, tobacco and alcohol use, preoperative irradiation and chemotherapy, previous neck surgery to the anastomosis side, type of recipient vessel and donor site, use of a coupler device, timing of the operation, and use of postoperative anticoagulants . Some of these factors have been shown to have no association with free flap failure. However, there is as yet no international consensus concerning whether factors such as diabetes mellitus, previous irradiation, previous neck surgery to the anastomosis side, choice of recipient vessel and donor site, use of a coupler device, and use of postoperative anticoagulants influence free flap outcomes.

Most studies investigating these factors have had their own limitations, such as a small sample size, differences in surgeon preferences and experience, and the inclusion of cases of breast or extremity reconstruction. This retrospective analysis of the data of 881 patients who underwent head and neck free flap reconstructions performed by a single surgical team (XP and YW) over a 4-year period was performed to overcome these limitations. The aim was to identify the risk factors for free flap failure after head and neck reconstruction.

Patients and methods

Patients

This study constituted a retrospective review of 881 consecutive free flaps in head and neck surgeries performed by a single surgical team between January 2013 and November 2016 at Peking University School and Hospital of Stomatology. The study was approved by the ethics committee for human experiments at the Peking University School and Hospital of Stomatology. The patient characteristics and surgical data, including patient age, diabetes mellitus, previous irradiation, history of previous neck surgery to the anastomosis side, donor sites, type of recipient vein, use of a coupler device, and use of postoperative anticoagulants, were recorded.

Data analysis

Each possible risk factor was examined by univariate analysis using the χ 2 test. Factors with P -values of <0.10 were included in multivariate logistic regression models to identify significant independent risk factors for free flap failure. All measured data were analyzed using SPSS version 17.0 software (SPSS Inc., Chicago, IL, USA). P < 0.05 was considered statistically significant.

Results

This retrospective study consisted of 881 microvascular free flap transfer surgeries. The surgeries were performed on 534 male subjects and 347 female subjects; their mean age was 48.87 years (range 6–83 years; median 51 years). The free flaps used for reconstruction included 548 fibula flaps, 165 anterolateral thigh flaps (ALTF), 134 radial forearm free flaps (RFFF), 20 iliac crest free flaps, 11 submental free flaps, and three rectus abdominis flaps ( Table 1 ).

Table 1
Patient characteristics and the donor sites used.
Flap success Flap failure Total
Sample size 855 26 881
Sex, male 522 12 534 (60.6%)
Age (years), mean ± SD 50.88 ± 16.09 48.81 ± 16.08 48.87 ± 16.08
Donor site
Fibula flap 536 12 548 (62.2%)
ALTF 157 8 165 (18.7%)
RFFF 130 4 134 (15.2%)
Iliac crest flap 18 2 20 (2.3%)
Submental free flap 11 0 11 (1.2%)
Rectus abdominis flap 3 0 3 (0.3%)
SD, standard deviation; ALTF, anterolateral thigh flap; RFFF, radial forearm free flap.

In all, 26 flaps were lost; the total free flap success rate was 97.0%. Venous thrombosis was the main cause of free flap failure (16/26), followed by arterial crisis (seven flaps: six arterial thrombosis, one vasospasm), haematoma (two flaps), and infection (one flap) ( Table 2 ). Thrombosis developed in 19 flaps (63.3%) in the first 48 h postoperatively and 11 flaps in the next 72 h ( Tables 2 and 3 ).

Table 2
Causes and outcomes of 49 take-back free flaps.
Cause Number of flaps Flap survival Flap loss
Venous thrombosis 24 8 16
Arterial thrombosis 6 0 6
Arterial vasospasm 1 0 1
Haematoma 13 11 2
Misplacement 4 4 0
Infection 1 0 1
Total 49 23 26

Table 3
Impact of timing of take-back surgery on flap survival.
Characteristic Number of flaps Salvage
Venous thrombosis
0–48 h 15 6
>48 h 9 2
Arterial thrombosis
0–48 h 4 0
>48 h 2 0
Arterial vasospasm 1 0
Haematoma
0–48 h 10 10
>48 h 3 1
Vessel misplacement 4 4
Infection 1 0

In all, 65 patients (7.4%) had a history of diabetes and 55 patients (6.2%) had undergone radiotherapy before surgery. Fourteen patients (1.6%) had a history of neck surgery to the anastomosis side. Branches of the internal jugular system (59.4%) and the external jugular vein (40.6%) were used as the recipient veins for anastomosis. Coupler devices were used to anastomose the blood vessels in 328 patients (37.2%). No anticoagulants were prescribed postoperatively in 158 patients (17.9%).

Univariate analysis in the 26 cases of unsuccessful free flap transfer indicated that a history of irradiation ( P < 0.001) and a history of the previous neck surgery to the anastomosis side ( P = 0.007) were two potential risk factors for free flap failure. Patient age ( P = 0.056), diabetes mellitus ( P = 0.750), choice of recipient vein ( P = 0.298), use of a coupler device ( P = 0.130), and anticoagulant use ( P = 0.141) were not associated with free flap outcomes ( Table 4 ). Logistic regression analysis identified a history of irradiation as a statistically significant risk factor for free flap failure ( P < 0.002; Table 5 ).

Table 4
Univariate analysis of potential risk factors for free flap failure.
Characteristic Flap success
( n = 855)
Flap failure
( n = 26)
P -value
Age (years)
≤50 426 8 0.056 a , *
>50 429 18
Diabetes
Yes 64 1 0.750 b
No 791 25
Previous neck surgery to the anastomosis side
Yes 11 3 0.007 c , *
No 844 23
Previous irradiation
Yes 48 7 <0.001 b,*
No 807 19
Donor site
Fibula flap 536 12 0.558 a
ALTF 157 8
RFFF 130 4
Recipient vein
IJS 505 18 0.298 a
EJV 350 8
Coupler device
Yes 322 6 0.130 a
No 533 20
Anticoagulants
Yes 705 18 0.141 b
No 150 8
ALTF, anterolateral thigh flap; RFFF, radial forearm free flap; IJS, internal jugular system; EJV, external jugular vein.

a Pearson’s χ 2 test.

b continuity correction.

c Fisher’s exact test.

* P < 0.1.

Dec 14, 2017 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Risk factors for free flap failure: a retrospective analysis of 881 free flaps for head and neck defect reconstruction
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