Perioperative factors that influence the outcome of microsurgical ...

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British Journal of Oral and Maxillofacial Surgery 53 (2015) 533–537

Perioperative factors that influence the outcome of microsurgical reconstructions in craniomaxillofacial surgery R.H.M. Preidl ∗ , F. Wehrhan, T. Schlittenbauer, F.W. Neukam, P. Stockmann Department of Oral and Maxillofacial Surgery, University of Erlangen, 91056 Erlangen, Germany1 Accepted 14 March 2015 Available online 8 April 2015

Abstract Microsurgical tissue transfer is a well-established way of reconstructing the head and neck, but there are still many postoperative complications that require revision. The aim of this study was to clarify perioperative factors and characteristics of patients that influence the success of the flap and the need for revision. We retrospectively studied 368 patients who were treated with microsurgical free tissue transfer in the head and neck area at the Department of Oral and Maxillofacial Surgery at the University Medical Centre, Erlangen, between 2004 and 2009. Investigations concentrated on patients’ characteristics and operative factors. Free scapular or parascapular flaps (n = 161, 44%) and radial forearm flaps (n = 119, 32%) were predominantly used for the reconstruction of major defects in the mandible and the floor of the mouth. In 39 patients (11%) revision was required, which resulted in a success rate of 96%. There was a significant association between preoperative American Society of Anesthesiologists (ASA) grade and postoperative survival of the flap (p = 0.04). Patients previously treated by irradiation required significantly more revisions than those not so treated (p = 0.04). The use of vein grafts was also significantly associated with the need for revision (p = 0.02). The ASA grade influenced the success rate but was not associated with the number of revisions. These factors must be taken into consideration when intervention is planned to reduce the number of postoperative complications and interventions further. © 2015 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Keywords: Microsurgical free tissue transfer; Perioperative factors; Operative revision

Introduction Microvascular transfer of tissue is widely accepted as a method of reconstruction of the head and neck area. During past decades various free flaps have been developed, and further modified for use in reconstruction.1 Microvascular free tissue transfer is now used more and more for patients with osteoradionecrosis (ORN) and bisphosphonateassociated osteonecrosis of the jaw (BRONJ), and many defects with varying dimensions and at various sites can

∗ Corresponding author at: Oral and Maxillofacial Surgery, University of Erlangen, Glückstraße 11, 91054 Erlangen, Germany. Tel.: +49 9131 8543724; fax: +49 91318533657. E-mail address: [email protected] (R.H.M. Preidl). 1 [email protected]

be successfully reconstructed with adequate functional and aesthetic outcomes.2 The overall success rate of microsurgical transfer of tissue in the head and neck is reported to be over 90%,3 but necrosis of the flap because of impaired perfusion mainly as a result of thrombosis, haematoma, or infection, is the main cause of failure and can be associated with serious life-threatening complications.4 Various predictive factors in patients’ characteristics at the time of operation, and differences in operative techniques, were identified in the past as having an influence on the outcome. Apart from the patients’ coexisting medical conditions, preoperative treatment with radiotherapy was one of the main factors that affected the postoperative course.5 However, the reports about factors that might potentially influence the failure of microvascular reconstructions are

http://dx.doi.org/10.1016/j.bjoms.2015.03.007 0266-4356/© 2015 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

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R.H.M. Preidl et al. / British Journal of Oral and Maxillofacial Surgery 53 (2015) 533–537

Table 1 Review of publications about operative revisions and success rates in microvascular tissue transfer. The percentage of revision procedures varies between 5% and 23%, whereas the success rate is over 90%. First author, year of publication, and reference

No of flaps

Study design

Revisions (%)

Success rate (%)

Eckardt 200318 Ferrari 201217 Gerressen 201319 Holom 201320 Hölzle 201021 Jonas 201222 Kesting 20118 Llorente 201323 Pohlenz 20127 Rosenberg 200924 Wolff 200825

500 360 406 143 166 125 161 259 1000 150 350

Retrospective Retrospective Retrospective Retrospective Retrospective Prospective Retrospective Retrospective Retrospective Prospective Retrospective

8 5 12 15 Not shown 14 23 Not shown 12 9 Not shown

94 97 92 92 93 94 98 92 94 95 95

heterogeneous, and the percentage of revisions required to treat malperfusion of flaps has varied from 5% to 23% (Table 1). We hypothesised that there are still unknown factors that influence not only the success rate of microsurgical transfer of tissue but also the need for revision procedures during the postoperative course. It was our aim, therefore, to evaluate and analyse postoperative complications in 368 cases of free tissue transfer in this retrospective study to see if we could support existing theories, and to describe any additional factors that we found.

Material and methods The medical records of 368 patients who were treated by microsurgical free flap reconstruction between 2004 and 2009 in the Department of Oral and Maxillofacial Surgery at the University Hospital Erlangen, Germany, were reviewed retrospectively. The mean (SD) age was 59 (13) years (range 7–86). Other personal and clinical details, which were abstracted from the patients’ medical records, are shown in Table 2. Data are expressed as mean (SD) or number (%), and the significance of differences was assessed with the help of IBM SPSS Statistics for Windows (version 19, IBM Corp, Armonk NY, USA) using the chi square test, Student’s t test, and the Mann–Whitney U test as appropriate. Probabilities of less than 0.05 were accepted as significant.

Results The results are shown in Table 2. All revisions were required during the first 24 h after the initial operation, and a reanastomosis of the affected vessel was necessary in all cases. Significantly more veins were affected than arteries (p = 0.02). In 3 cases (8%) the salvage operation was unsuccessful, and flaps became necrotic. Loss of a flap was not associated with the need for revision (p = 0.18), and differences in the frequency of revisions, the type of flaps, and the

indication for operation (cancer or not) were not significant either (p = 0.85 and p = 0.11). The patients’ general health, as reflected in the preoperative ASA grade, also influenced the incidence of postoperative loss of a flap (p = 0.04), but such loss was seen only among patients whose original ASA grade was II or more. There was a significant positive correlation between age and ASA grade (p = 0.02). Previous treatment with radiotherapy had a significant effect on the number of revisions, with significantly more re-explorations required in patients given radiotherapy than in those not so treated (p = 0.04). However, there was no association between loss of a flap and preoperative radiotherapy (p = 0.56).

Discussion Microsurgical tissue transfer has developed into a reliable alternative to regional tissue transfer, and has become a well-established technique in oral and maxillofacial surgery.1 Unfortunately it is associated with serious and possibly life-threatening complications both regarding the transferred tissue itself, or the patients’ general condition, and this influences both healing capacity and duration of hospital stay.6 Like other authors, we have analysed the impact of perioperative factors that lead not only to the failure of different kinds of free flaps but also to the need for revisions.7–9 We have reported an overall success rate of 96% over a period of 6 years, which compares well with other published data (Table 1). Loss of a flap is correlated with arterial or venous thrombosis, which usually happens within the first 72 h and is treated by revision of the anastomoses and removal of the thrombus. In our study as well as others the number of revisions of microvascular anastomoses was greater than the number of flaps lost. Our results showed that only 3/39 flaps failed after re-exploration, which emphasises the importance of monitoring perfusion of the flap postoperatively, and immediate intervention if anything goes wrong.


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Table 2 Perioperative factors that influenced the need for revision and loss of flaps in 368 cases of microvascular tissue transfer. Need for revision

Sex Male Female ASA grade I–II III–IV Site of defect Maxilla Mandible Floor of the mouth Tongue Tonsils Salivary glands Cheek Midface Upper face Soft palate Indication for operation Osteoradionecrosis Recurrent cancer Primary cancer Secondary reconstruction Metastasis Other Source of flap Radial forearm Latissimus dorsi Lateral upper arm Fibular Scapular/parascapular Anterolateral thigh Preoperative radiotherapy Yes No Vein graft Yes No Technique for arterial anastomosis End-to-end End-to-side Supplying artery External carotid Superior thyroid Maxillary Facial Lingual Temporal Submental Transverse cervical Superior labial Supplying vein Internal jugular Facial Superior thyroid External jugular Temporal Two and more Bony resection and reconstruction No Resection only Resection and reconstruction

Flap loss

Yes

No

p value

Yes

No

p value

26 13

239 90

0.44

12 2

253 101

0.37

24 15

213 116

0.69

3 11

228 126

0.04*

5 19 7 5 1 0 1 1 0 0

24 112 91 57 7 1 8 8 12 9

0.34

1 7 3 0 2 0 0 0 0 1

28 124 95 62 6 1 9 9 12 8

0.06

7 10 18 2 1 1

47 40 206 11 5 20

0.11

3 3 8 0 0 0

51 47 216 13 6 21

0.80

12 2 2 2 21 0

107 22 35 20 140 5

0.85

4 2 0 1 7 0

115 22 37 21 154 5

0.54

17 22

90 239

0.04*

5 9

102 252

0.56

7 32

21 308

0.02*

2 12

26 328

0.29

28 11

253 76

0.49

9 5

272 82

0.33

14 10 0 9 5 0 0 0 0

128 118 4 62 10 6 1 1 1

0.11

5 5 0 3 1 0 0 0 0

137 123 4 68 14 6 1 1 1

0.85

23 2 4 0 1 9

192 22 25 16 4 70

0.48

9 2 1 1 0 1

206 22 28 15 5 78

0.43

8 9 22

99 71 159

0.43

2 4 8

105 76 173

0.41

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Table 2 (Continued) Need for revision

Loss Yes No ∗

Flap loss

Yes

No

p value

3 36

11 318

0.18

Yes – –

No

p value

– –

p < 0.05 was considered as significant.

Previously irradiated graft beds are particularly likely to present with impaired wound healing and the increased likelihood of fibrosis, which leads to disordered healing and postoperative infections.10 There is also a significant increase in the need for postoperative exploration in irradiated patients, presumably because radiation-induced vasculopathy leads to increased vascular dysfunction within the vessels that supply the flap. However, as we focused only on failure of the anastomoses, we have only limited data on the postoperative course of patients previously treated by irradiation as far as their infective state and general health were concerned. The interposition of vein grafts is still controversial. Furr et al. presented a retrospective study of 1143 patients with no significant differences in survival of flaps in cases with a vein graft compared with control.11 However, others have reported increased failure rates that might be associated with the fact that vein grafts are used in cases where there is no available vessel for anastomosis within the reach of the pedicle.12 This can be seen for example, in previously irradiated patients who needed a vein graft (22/28 grafts in our analysis). Depending on the kind of defect and the aesthetic and functional requirements, we use different types of free flaps. The radial forearm flap is one of the most commonly used,13 but though it gives adequate functional outcome (particularly in bony reconstructions) and has a success rate of over 95%, it is not the only successful flap. Other flaps, such as the scapular or parascapular flap (which is the most used in our department) turned out to be both successful and reliable, and were not associated with more malperfusions and the need for revisions. This is supported by the fact that we found no significant association between the type of flap and the number of revisions or failures in this study. In addition there was no significant correlation between the need to resect or reconstruct bone and either the need for revision or final failure of the flap. Currently there are heterogeneous data from clinical studies about the microsurgical techniques used, the total number of anastomosed veins, and their correlation with postoperative complications. Investigations have already shown that double venous anastomoses have a beneficial effect on survival of flaps compared with single venous drainage.14 However, we found no more lost flaps or revisions whatever the venous drainage, which might be because all sorts of flaps were included in the analysis. To investigate this topic further, blood perfusion and failure of flaps should be measured separately for each type and size of flap. The artery usually used for anastomoses and blood supply in our analysis was the external carotid artery in 39%

of cases, whereas in other current publications the external carotid artery was used in less than 10% of cases and the facial and superior thyroid arteries were the most common.15 This difference might have arisen because our analysis was retrospective, and we might have overestimated it. The success of microsurgically transplanted free flaps correlates with the general health of the patient as reflected in the ASA grade, and this was verified in our study. There are also other tools such as the Adult Comorbidity Evaluation-27 index (ACE-27) or the Eastern Cooperative Oncology Group (ECOG) which have been found to be useful in prospectively evaluating patients’ risk of complications in microvascular free tissue reconstructions.16 Surprisingly, although the ASA grade was significantly associated with increasing age in our analysis, the number of revisions and failures of flaps was not related to the age of the patient. This is in a line with data published by Ferrari et al., who showed that increasing age was not significantly associated with the incidence of postoperative complications.17 In conclusion, microvascular free tissue transfer is a reliable and successful method of reconstruction in the head and neck, and is independent of the patient’s age. However, one should carefully assess and investigate the patients’ general health and coexisting conditions beforehand, and monitor flap perfusion carefully (particularly in patients previously treated with irradiation) to improve the postoperative outcome further and reduce the need for revision.

Conflict of interest We have no conflicts of interest.

Ethics statement/confirmation of patients’ permission This study has been approved by the ethics committee of Friedrich-Alexander University Erlangen-Nürnberg (No. 83 13B).

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