4th November 2011, Volume 124 Number 1345

Ryan Gao, Stanley Loo

After decades of refinement of surgical techniques and improved perioperative management, free flaps have become accepted as the procedure of choice for reconstructing many complex wound defects. Success rates exceeding 90% have consistently been reported in the international literature.1–4 Nevertheless, complications from free flap reconstructions inevitably occur and flap failure can be disastrous for both the patient and the surgical team involved.

Herein, we report the outcome of 100 consecutive free flap reconstructions from our regional plastics and reconstruction centre.

Method

100 consecutive free flap reconstructions from January 2004 to April 2010 were identified from the Middlemore Hospital Theatre Coding List. Patients who were identified as having undergone a ‘free flap’ operation or any subtype of free tissue transfer [e.g. latissimus dorsi (LD), serratus anterior (SA), anterolateral thigh (ALT) etc] were included in the study.
Basic patient demographics were recorded as well as indication for surgery and type of free flap. Adverse outcomes were recorded as free flap failure or other complications including infection, venous congestion, dehiscence, haematoma formation, and vascular thrombosis.

Results

100 consecutive free flap reconstructions were performed on 96 patients by 17 consultant plastic surgeons during the study period. One patient received two LD flaps following bilateral forefoot amputations as a result of meningococcal septicaemia. Another patient received two free flaps (LD and SA) following Gustilo-Anderson type IIIB injuries to both his legs.5 Two patients underwent successful repeat free flaps following failure of the first operation. There were 34 females and 62 males. The median age at the time of surgery was 43 years (range 3–79 years). The most common indication for free flap reconstruction was limb trauma (60%), followed by tumours (13%), infections (11%), mastectomies (10%), burns (3%) and iatrogenic causes (3%) (Table 1).

Table 1. Indications for free flaps versus complications
Indications
No.
Complica-tions
Thrombosis
Infection
Ischaemia
Haematoma
Venous congestion
Dehiscence
Limb trauma
MVA
Non MVA
Tumours
Limb
Head and neck
Trunk
Infection/necrosis
Chronic ulcer
Osteomyelitis
Necrotising fasciitis
Gangrene
Mastectomy
Burns
Iatrogenic
Redo Flap
Postoperative wound
60
38
22
13
7
5
1
11
5
3
2
1
10
3
3
2
1

8
5
3
1
0


1


1
0
2
0

4 (1†)
1

1†
1

3
2





1




1

1‡
1‡










1‡


1‡

1†




1†











1‡
Total
100
21
7
7
3
2
1
1
† Associated with flap failure; ‡Associated with partial flap failure; MVA=Motor vehicle accident.

Ten different types of free flaps were utilised during the study period (Table 2). Three types of free flaps (LD, ALT and transverse rectus abdominus myocutaneous [TRAM]) contributed to 65% of the total cases. Flap failures occurred independently compared to the types of flaps used. Specifically, there was one failure from each of the LD, TRAM, gracilis and fibular flaps. The LD was the most widely utilised flap accounting for 26% of the total cases. Half of the TRAM flaps (10/20) were performed for breast reconstruction following mastectomies. The use of ALT flaps proved to be extremely safe in this series; of the 19 ALT flaps utilised, only three complications occurred (two infections and one partial flap failure). On the contrary, complications from gracilis and fibular flaps were high, 3/9 and 2/6 respectively, including one failure from each of these two types of flaps.

Table 2. Free flap types versus complications
Flap type
No.
Complica-tions
Thrombosis
Flap infection
Ischaemia
Haematoma
Venous congestion
Dehiscence
LD
TRAM
ALT
Radial forearm
Gracilis
Fibular
Parascapular
Others
Lateral forearm
Serratus anterior
Iliac crest
26
20
19
11
9
6
1
8
4
2
2
6
3
3
3
3
2
1
0

1†

3
2 (1†)
1
4
1
2
1‡
1‡




1‡
1†



1‡





1†


1‡
Total
100
21
7
7
3
2
1
1
† Associated with flap failure; ‡Associated with partial flap failure; LD=Latissimus dorsi; TRAM=Transverse rectus abdominus myocutaneous; ALT=Anterolateral thigh.

Overall, 21 complications occurred without any perioperative mortality. All seven cases of postoperative infections responded well to intravenous antibiotics. Fourteen flaps were taken back to the operating theatre for further procedures, of which, ten (71%) were successfully salvaged (Table 3). Eight flaps required redo of vascular anastomosis (seven venous and one arterial).

Five out of the eight (63%) redo anastomosis were successful, with the help of medicinal leeches in two cases. Five flaps required debridement of partial ischaemic tissue. The resulting defects were able to be primarily closed in three cases. Split-thickness skin graft was used for soft tissue coverage following debridement of a LD and a gracilis flap. The reasons for the partial flap failures were not accurately recorded for all five cases. However, it was evident from the clinical documents that haematoma formation and wound dehiscence were to blame for partial failure of the gracilis and the ALT flaps respectively.

Table 3. Free flaps taken back to theatre
Flap type
No.
Flaps taken back to theatre
Redo venous anastomosis
Redo arterial anastomosis
Debridement of partial ischaemic tissue
Unsuccessful evacuation of haematoma
LD
TRAM
ALT
Radial forearm
Gracilis
Fibular
Parascapular
26
20
19
11
9
6
1
2
2
1
3
3
2
1

1†

3 (2xLeech)
1
2 (1†)




1†
1‡ + SSG
1‡
1‡

1‡ + SSG

1‡
1†
Total
92
14
7
1
5
1
† Associated with flap failure; ‡Associated with partial flap failure; Leech: medicinal leech therapy; SSG=Split-thickness skin graft; LD=Latissimus dorsi; TRAM=Transverse rectus abdominus myocutaneous; ALT=Anterolateral thigh.

Discussion

Free flap failure is a dreaded complication which plagues even the most experienced microvascular surgeons. The repercussions of flap failure include poor functional and cosmetic outcomes for the patient along with devastating psychological impact on both the patient and the surgical team involved.

Studies which have investigated the causes of flap failures have shown that vascular compromise is the leading cause of flap failures in the immediate postoperative period. Furthermore, venous thrombosis occurs much more frequently than arterial occlusions.6-10 On the other hand, flaps that fail after 48 hours were mostly due to mechanical stress around the anastomosis. Factors that predispose to mechanical stress around the anastomosis include haematoma formation, physical kinks in the vascular loop, poor flap design or inappropriate in-setting during the time of surgery.7

In our series of 100 consecutive free flaps, a total of four flap failures occurred (Table 4). Three flaps failed as a result of vascular thrombosis, including two venous and one arterial thrombus formation. The fourth case failed as a result of mechanical stress around the anastomosis caused by a large haematoma.

Table 4. Flap failures
Cases
No. 1
No. 2
No. 3
No. 4
Flap type
Gracilis
TRAM
Fibular
LD
Age/gender
47yo/M
49yo/F
49yo/M
73yo/F
Indication
Trauma
Tumour
Tumour
Tumour
Causes of failure
Arterial thrombus
Venous thrombus
Venous thrombus
Haematoma
Identifiable factors Attributable to failure
Arterial thrombus
Prolonged operation
Convoluted anastomosis
Mechanical obstruction
Outcome
Redo flap
Redo flap
Resection
Resection

LD=Latissimus dorsi; TRAM=Transverse rectus abdominus myocutaneous.

It is worth noting that the most common indication for free flap coverage in our series was limb trauma (60% of total cases). This is reflective of the fact that our plastics unit is part of a large tertiary trauma centre. Thirteen complications arose from this cohort of patients including one flap failure.

The flap failure occurred in a 47-year-old patient who sustained a Gustilo-Anderson type IIIB distal tibia fracture as a result of a motor vehicle accident.5 He underwent an uncomplicated intramedullary nailing of the fracture and subsequently proceeded to have a free gracilis flap for coverage of the resulting pre-tibial soft tissue defect.

Two hours postoperatively, it was noted that the flap became ischaemic and the patient returned to theatre for exploration. A small arterial thrombus was identified approximately 1cm distal to the anastomosis. Despite thrombecotomy, the gracilis flap failed to survive and the patient underwent a successful free LD flap 5 days later. Arterial thrombus is known to be associated with a poor flap outcome even with prompt salvage attempts. In Nakatuska’s review of 2372 free flaps for head and neck reconstruction following cancer resection, arterial thrombectomy was successful in only 15% of cases.11

Free flap coverage for soft tissue defects following tumour resection accounted for 13% of the total cases performed during the study period. A disproportionally high number of complications occurred in this cohort of patients including three failures. Venous thrombosis was accountable for two of the failures and the final flap failure was caused by a large haematoma causing mechanical stress around the anastomosis.

The second free flap failure in our series occurred in a patient who underwent resection of a high grade leiomyosarcoma from her thigh with immediate TRAM flap reconstruction. The patient had an extended procedure with total operative time of more than 12 hours. Strong Doppler signals were recorded during and shortly after the operation. However, two hours postoperatively the flap was found to be ischaemic and upon exploration in the operating theatre, a venous thrombus was evacuated distal to the anastomosis.

The salvage procedure proved to be futile with the flap again becoming ischaemic several hours later requiring complete resection. The patient subsequently underwent a successful LD flap 2 weeks later. Prolonged operation time of more than 10 hours has been shown to be a significant risk factor for poor flap outcome including failure.12-15 Another predictor of flap outcome has been shown to be the number of operating surgeons in theatre.16,17 Intuitively, longer operations with more surgeons often equate to higher degree of surgical complexity, greater intraoperative fluid shifts, greater risks of infections and longer ischaemia period.12

Extended ischaemia time increases the risk of anoxic injury as a result of anaerobic metabolism and the accumulation of inflammatory mediators. In addition, following re-establishment of vascular flow following prolonged ischaemia; the incidence of reperfusion injury also increases markedly with resultant deleterious effect on flap survival.12 Furthermore, surgeon fatigue associated with extended operating time may potentially affect proper tissue handling, vessel preparation and anastomosis, flap insetting and skin closure.

The third flap failure occurred in a patient who underwent reconstruction of his humerus with a free fibular flap. The patient originally had resection of an aggressive fibromatosis from his left humerus with intercalary allograft reconstruction and plating. The allograft was complicated by wound infections requiring multiple debridements, long term antibiotics and ultimately removal of the allograft and insertion of cement spacer.

Two years after his primary resection, the patient proceeded to have a free fibular flap to reconstruct his humerus. Approximately 4 hours after the operation, the flap was found to show signs of venous congestion. Upon urgent exploration in the operating theatre, the arterial anastomosis was found to be patent and functional. However, a very convoluted venous anastomosis was identified with evidence of venous congestion. The excessive redundancy in the venous anastomosis was excised and the ends re-anastomosed.

Unfortunately, the flap failed to survive and the patient eventually underwent excision of his fibular flap and an en bloc upper humeral interscapulothoracic resection. The nature of this retrospective review precluded accurate assessment of the reason why there was such a convoluted venous anastomosis. Nevertheless, better flap design with particular attention paid to the venous anastomosis and more careful in-setting of the flap may have made a difference in the outcome of this fibular flap.

The final flap failure occurred in a 73-year-old lady with a history of large malignant fibrous histiocytoma over her thigh involving all four quadriceps muscles. She underwent wide local excision with neoadjuvant radiotherapy and a delayed LD flap for coverage of the soft tissue defect a month later. Approximately 4 hours postoperatively; the flap appeared to be congested with poor Doppler signals. Upon urgent exploration, a large haematoma was identified deep to the flap with evidence of diffuse bleeding points around the anastomosis. The anastomosis was found to be patent and functional without any evidence of thrombosis. The haematoma was evacuated and the bleeding vessels cauterised.

Unfortunately, the flap continued to show signs of worsening congestion and the patient returned to theatre 6 hours later for repeat exploration. Intraoperatively it was noted that there were generalised ooze from the wound with more focal bleeding vessels which were again cauterised. The flap was re-inset and the wound closed. Fourty-eight hours later, the flap was found to be necrotic and was excised. It is postulated that the persistent wound ooze and microvascular bleeding may have been related to the harmful effects of neoadjuvant radiotherapy on local tissues and vasculature.

An in vitro comparative study of biopsies from irradiated versus unirradiated arteries in 147 patients undergoing free flap surgery showed that radiation caused significant intimal thickening.18 The authors also noticed an increase in proteoglycan deposition and inflammatory cell content in the irradiated vessels. Whilst some studies have echoed the increased risk of recipient site complications in post-irradiated wound beds,13,17,19 the majority of published literature thus far has failed to show any statistically significant effect of radiotherapy on the overall rate of free flap complications or length of hospital stay.8,12,20–23

In their retrospective review of 185 consecutive free flap reconstructions, Clark et al concluded that surgeons should not be deterred from performing free tissue transfer for reconstruction in post-irradiated wounds.17

Conclusion

Free flaps are safe and reliable reconstructive options particularly for complex defects. The present study showed that free flap reconstructions in our regional plastics and reconstruction centre have excellent success and salvage rates and the results are comparable to international literature. It must be re-iterated that full institutional support in the form of allocation of theatre time, personnel and training of allied health staff to effectively monitor postoperative patients is essential to ensure free flap success.

Summary

Free flap surgery is an integral part of modern day plastic surgery. The operation involves the transfer of tissue, along with its blood supply from the original (donor) location to another (recipient) location. Free flaps are extremely versatile and they can be performed for a variety of reasons including reconstructing a breast following breast cancer surgery; coverage of a defect following tumour resections from the head and neck region and coverage of exposed bones following repair of fractures. After decades of refinement of surgical techniques and improved perioperative management, success rates of more than 90% have widely been reported in the international literature. This study showed that free flap reconstructions in our regional plastics and reconstruction centre have an excellent success rate (96%); and the results are comparable to international literature.

Abstract

Aim

Colonic SEMS are increasing used in the management of acute large bowel obstruction, both as a bridge to surgery and as a definitive palliative measure in patients unfit for surgery. We describe our experience from a New Zealand hospital and compare our data with that already published in literature.

Method

In this retrospective 4-year study, data was collected from the case notes of 28 consecutive patients with acute large bowel obstruction referred for colonic SEMS. Uncovered Boston Scientific colonic SEMS were placed endoscopically under fluoroscopic guidance. Technical success was considered as correct placement of stent after deployment and clinical success as the passage of flatus and faeces after stent insertion. Data was analysed using descriptive statistics.

Results

Our technical and clinical success rates were 90% and 88% respectively. The procedure was palliative in 15 patients and as a bridge to elective surgery in 13 cases. Procedure-related mortality was 7%. It was because of one early and one late perforation. The average length of stay post procedure was 2 days. Mean survival post stent insertion in the palliative group was 2.4 months and for those with a bridge to surgery was 14 months.

Conclusion

Our results support the data published from international centres in terms of deployment of SEMS in patients with acute large bowel obstruction, both as a bridge to surgery and as a definitive palliative measure.

Author Information

Ryan Gao, House Officer; Stanley Loo, Consultant Plastics and Reconstructive Surgeon; Middlemore Hospital, Auckland

Correspondence

Ryan Gao, Department of Plastics and Reconstructive Surgery, Middlemore Hospital, Hospital Road, Otahuhu, Auckland, New Zealand. Fax: +64 (0)9 8496238

Correspondence Email

ygao921@gmail.com

Competing Interests

None.

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