Abstract
The aim of this study was to report the clinical features, reliability, and various applications of free anterolateral thigh (ALT) flaps and to provide a 10-year retrospective review of the application of this flap in head and neck tumour patients. A retrospective study was performed of 872 patients who underwent immediate reconstruction of head and neck tumour-induced defects with ALT flaps between April 2005 and April 2014. The study sample consisted of 609 males and 263 females aged 18–79 years. The shapes and sizes of the flaps were designed individually to meet various demands of reconstruction in the head and neck region. The overall rate of successful reconstruction was 97.4%. The reasons for 57 cases of flap compromise were analyzed. The time to detection of flap crisis was often within the first 8 h after surgery (64.9%). One- and two-vein anastomosis strategies in microsurgery were compared, and significant differences were observed in terms of the time to detection of flap compromise and the rate of successful flap salvage. In conclusion, the free ALT flap provides unique features for the reconstruction of oral and facial defects in a reliable and versatile approach. The ALT flap is a favourable and versatile ‘workhorse’ flap for head and neck reconstruction.
The surgical treatment of various head and neck tumours may result in severe defects, which may significantly reduce quality of life. The reconstruction of such defects is a high priority for head and neck surgeons and plastic surgeons. The demands of oral and maxillofacial reconstruction are increasingly high, from shape recovery to functional and aesthetic restoration, providing an increased quality of life after surgery. Great progress has been made in maxillofacial reconstruction surgery to achieve better cosmetic and functional outcomes. Loco-regional flaps such as the platysma musculocutaneous flap and pedicled flaps like the pectoralis major myocutaneous flap have been used widely, while free flaps have undoubtedly heralded a revolution in head and neck reconstruction. Progress in microsurgery has also made the free flap a more reliable choice.
Craniofacial and neck tumour-induced defects consist largely of multi-fold soft defects, including defects of the facial skin, mucosa, muscle of the tongue, cheek, and floor of the mouth. Favourable reconstruction requires a free flap that is reliable and pliable and supplies sufficient tissues; the length of the pedicle and diameter of the pedicle-containing vessels should be appropriate for vascular anastomosis. Over the last several decades, numerous free flaps have been introduced and applied in oral and facial defects, including the free anterolateral thigh flap (ALT) and latissimus dorsi flap. The introduction of the first free ALT flap in 1984 by Song gained worldwide attention, and many studies have since reported the features of the ALT flap. The donor site contains abundant soft tissues, and different types of flap can be harvested and tailed, such as fasciocutaneous, musculocutaneous, perforator, adipofascial, thinned ALT, de-epithelialized, folded, and chimeric flaps. The clinical value of the ALT flap is also widely recognized, and many advances in surgery related to the harvesting and application of ALT flaps have been reported in the literature. However, large-scale systematic and comprehensive studies on ALT flap utilization in head and neck reconstruction are still limited, which may reduce the variation by different surgical techniques. In the present study, the data of 872 patients who underwent tumour resection and immediate reconstruction using ALT flaps were investigated with the aims of presenting our experience of the use of the ALT flap and providing information on this ‘workhorse’ free flap.
Methods
Patients and surgical procedures
A total of 872 patients who underwent tumour excision and immediate reconstruction with an ALT flap at the Hospital of Stomatology, Wuhan University or Second Xiangya Hospital, Central South University, were recruited into this retrospective study. General patient information was collected, including age, gender, the site and pathological features of the tumour, and previous treatment.
All surgical procedures were performed simultaneously using a ‘two-team’ approach. The experienced senior surgeons were responsible for tumour resections, which were performed with or without neck dissections depending on the nodal status. The other team was responsible for reconstruction of the defects, including flap harvesting, vascular anastomosis, and postoperative flap monitoring.
The flaps were harvested according to the standard procedures mentioned in the literature, with several modifications. Doppler ultrasonography was used to assist in locating the perforator position before surgery. Surgical procedures consisted mainly of incision line design, localization of the perforators, and harvesting and preparing the ALT flaps. After localization of the perforators, the rectus femoris muscle was retracted internally to expose the branches of the lateral circumflex femoral artery (LCFA). The perforators were then dissected along the branch to the main trunk of the lateral circumflex femoral system while carrying the required muscle tissue. The skin paddle was incised after freeing the pedicle. Different types of ALT flap, such as musculocutaneous, fasciocutaneous, chimeric, folded, thinned, de-epithelialized, and myofascial, were designed and harvested based on the size and shape of the defect. Good communication was maintained between the two teams during this procedure because any extension of the excision could affect the reconstruction required to a significant degree. Data on the flap types, perforators, and pedicle features were collected for this study. After completion of the tumour resections, vascular anastomoses were performed using hand-sewing and/or mechanical techniques. Two- and one-vein anastomosis strategies with the hand-sewing technique were applied separately in 389 cases in this study during the 2 years from April 2012 to April 2014; differences between the two types of vein anastomosis strategy were compared. The donor sites were closed primarily in almost all cases; otherwise a skin graft was applied to close wounds.
Postoperative flap monitoring and follow-up
Postoperatively, clinical examinations and peripheral vascular Doppler ultrasound testing were used for flap monitoring. Flap monitoring was performed every 30 min for the first 24 h, then every 1 h for the second and third days, and then every 24 h for the following days. In the case of adverse changes in the flap, such as a change in colour to pale or dark, a loss of lustre, or a lowering in temperature, an acupuncture bleeding test using needles (diameter 0.5 mm) was done. Doppler ultrasonography was then also used to judge the patency of the anastomosed vessels. Low molecular weight heparin calcium (5000 IU) injection was used to prevent thrombus and/or papaverine to prevent arteriospasm in the situation in which a blood flow Doppler signal was still observed. Exploration and salvage surgery was performed immediately if the flap did not improve during the next 2 h of monitoring. In completely failed cases, the ALT flap was replaced with another flap, such as a contralateral ALT flap, free radial forearm flap, pedicled pectoralis major myocutaneous flap (PMMF), etc.
The duration of follow-up ranged from 6 to 50 months, with an average of 27 months. During follow-up, the cosmetic results were evaluated by clinical examination and medical photography and the patient’s own perception; the aesthetic outcome was categorized as good, satisfactory, or unsatisfactory. Diet was assessed by the patient’s dietary intake and was classified as tolerating a normal diet, a soft diet, or a liquid diet. The assessment of speech was based on whether the patient could be understood easily by a listener (fluent and intelligible) or whether it required concentration on the part of the listener (intelligible with effort). Speech was judged as unintelligible if the patient could not be understood.
Statistical analysis
Comparisons between the one- and two-vein anastomosis strategies was done by χ 2 analysis and/or the Student’s t -test using IBM SPSS Statistics for Windows, version 19.0 software (IBM Corp., Armonk, NY, USA). A P -value of <0.05 was considered statistically significant.
Multivariate logistic regression analysis was used to investigate risk factors for flap failure among the flap compromise cases using IBM SPSS Statistics for Windows, version 19.0 software. Odd ratios (OR) are provided with 95% confidence intervals (CI). A P -value of <0.05 was considered statistically significant.
Results
The subjects consisted of 609 males and 263 females aged 18–79 years (mean 43.6 years). The length of hospitalization ranged from 5 to 23 days, with a mean duration of 11.8 days. In terms of the site and histological features of the tumours, the most common defects resulted from tongue tumours and a squamous cell carcinoma (SCC) pathology. In addition to SCC, other pathological types of tumour, including sarcoma, adenoid cystic carcinoma, and mucoepidermoid carcinoma, were also included in this study. Cervical lymph node dissections were performed at the same time in 660 cases of malignant carcinoma. The skin paddle area of the flaps ranged from 12 cm 2 (4 cm × 3 cm) to 224 cm 2 (28 cm × 8 cm), with the average flap measuring 45 cm 2 (9 cm × 5 cm). ALT myocutaneous flaps were the most commonly used in this study, accounting for 79.9% of the total cases.
During flap elevation, 1040 perforators emerged and 936 of these perforators were selected to supply the skin paddles. The number of perforators in each case ranged from one to three based on the size of the skin paddle and flap type, with an average of 1.4. Perforators were concentrated near the iliac patellar connection line, and 775 (82.8%) perforators were confined to the inner and outer sides of the line within a width of 2.5 cm. A total of 936 perforators were present in the pedicles; descending branches, transverse branches, and ascending branches of the LCFA gave off 782, 142, and 12 perforators, respectively, among cases included in this research. Pedicle lengths varied from 6 cm to 18 cm, with an average length of 8.2 cm. Descriptive features of all study subjects are summarized in Table 1 .
| Clinical features | No. (%) |
|---|---|
| Gender | |
| Male | 609 (69.8%) |
| Female | 263 (30.2%) |
| Location | |
| Tongue | 342 (39.2%) |
| Cheek | 202 (23.2%) |
| Gingiva | 123 (14.1%) |
| Floor of the mouth | 51 (5.8%) |
| Retromolar region/oropharynx | 92 (10.6%) |
| Palate | 34 (3.9%) |
| Parotid gland/lateral deep face | 28 (3.2%) |
| Pathology | |
| OSCC | 692 (79.4%) |
| Adenoid cystic carcinoma | 75 (8.6%) |
| Mucoepidermoid carcinoma | 33 (3.8%) |
| Sarcoma | 31 (3.6%) |
| Other carcinoma | 23 (2.6%) |
| Benign tumour | 18 (2.1%) |
| Flap type | |
| Musculocutaneous | 697 (79.9%) |
| Fasciocutaneous | 78 (8.9%) |
| Chimeric/folded | 36 (4.1%) |
| Thinned | 38 (4.4%) |
| De-epithelialized/myofascial | 23 (2.6%) |
| Perforator type | |
| Musculocutaneous | 682 (72.9%) |
| Septocutaneous | 175 (18.7%) |
| Direct | 79 (8.4%) |
| Total | 936 |
| Associated branch of LCFA | |
| Descending | 782 (83.5%) |
| Transverse | 142 (15.2%) |
| Ascending | 12 (1.3%) |
| Total | 936 |
The mean time taken to harvest the flap was 40.5 ± 9.5 min, while the average time taken to perform the vascular anastomosis was 36.8 ± 4.6 min. Recipient vessels were the following: superior thyroid artery in 626 cases, facial artery in 139 cases, lingual artery in 46 cases, external carotid artery in 38 cases, and superficial temporal artery in 23 cases. The internal jugular vein was the most commonly used recipient vein, among which an end-to-end anastomosis with a suitable trunk of internal jugular vein was performed 782 times and an end-to-side anastomosis 460 times. The external jugular vein and facial vein were used in 89 and 65 cases, respectively.
Eight hundred and fifteen cases were successful without flap crisis. Of the 57 flap crisis cases, 34 (59.6%) flaps survived after salvage surgery, among which were nine cases of partial failure with flap retention. The overall rate of successful reconstruction was 97.4% (849/872). Total flap failure occurred in 23 cases in which the initial flaps were abandoned and replaced with other flaps in a second tissue transfer. Among the 57 flap compromise cases, there was a venous crisis in 39 cases and an arterial crisis in 13 cases; the remaining five cases emerged from both arterial and venous crises. Thirty-seven (64.9%) flap crisis cases were identified within 8 h after surgery, 15 were identified at 8–24 h after surgery, and five at >24 h after surgery. The latest flap crisis was identified on the fourth day postoperatively.
The proximate causes of flap crisis are presented in Table 2 . According to the multivariate logistic regression analysis for outcome (flap failure) among patients with flap crisis, the time to detection of the flap crisis (>8 h post-surgery), anastomosis time (>90 min), and old age (>60 years) were the potential risk factors in terms of flap failure ( Table 3 ).
| Reason for ALT flap crisis | No. (%) |
|---|---|
| Adverse surrounding pressure | 19 (33.3%) |
| Operative injury to pedicles/perforators | 15 (26.3%) |
| Abnormal position of pedicles/perforators in surgery | 11 (19.3%) |
| Primary clot at anastomosis site | 5 (8.8%) |
| Bad posture/mobilization of body | 2 (3.5%) |
| Negative drainage devices | 1 (1.8%) |
| Undefined reasons | 4 (7.0%) |
| Total | 57 |
| Variables | OR (95% CI) | P -value | |
|---|---|---|---|
| Age (years) | <45 | 1 | |
| 45–60 | 0.811 (0.534–1.232) | 0.272 | |
| >60 | 1.496 (1.076–2.080) | 0.031 | |
| Comorbidities | Normal | 1 | |
| Abnormal | 1.198 (0.569–2.224) | 0.474 | |
| Anastomosis time (min) | ≤90 | 1 | |
| >90 | 1.254 (1.000–2.676) | 0.017 | |
| Time to detection of flap crisis post-surgery (h) | <8 | 1 | |
| 8–24 | 2.740 (1.116–6.997) | 0.021 | |
| >24 | 5.976 (2.110–12.709) | 0.003 | |
| Use of anti-coagulation therapy | Yes | 1 | |
| No | 1.146 (0.719–1.723) | 0.856 | |
The two- or one-vein anastomosis strategy with hand-sewing technique was applied separately in 389 cases in this study. On statistical analysis, there was no significant difference in the recipient vessels, age, gender, flap sizes, or postoperative anticoagulation therapy between the two groups ( P > 0.05). The different options of one- or two-vein anastomosis had no significant effect on the rate of flap crisis ( P > 0.05). However, in terms of the time to detection of the flap crisis, this was significantly earlier in the one-vein anastomosis cases than in the two-vein anastomosis cases ( P < 0.05). Also, there was a significant difference between the two groups in relation to the success rate of salvage surgery ( P < 0.05). The outcomes of the two types of vein anastomosis strategy in 389 patients treated between April 2012 and April 2014 are shown in Table 4 .
| Variable | One-vein anastomosis | Two-vein anastomosis | P -value |
|---|---|---|---|
| No. | 189 | 200 | – |
| Duration of microsurgery (min), mean ± SD | 30.2 ± 6.9 | 45.6 ± 10.7 | >0.05 |
| Flap compromise, n (%) | 13 (6.9%) | 15 (7.5%) | >0.05 |
| Time to detection of flap crisis (h), mean ± SD | 10.1 ± 7.9 | 20.8 ± 8.2 | <0.05 |
| Successful salvage surgery, n (%) | 10 (76.9%) | 7 (46.7%) | <0.05 |
Short-term complications, including unsatisfactory wound healing (68; 7.8%) and partial necrosis of the skin paddle of the flap (23; 2.6%), were detected. All flap areas below 8 cm × 22 cm were directly sutured at the donor site. Only 27 (3.1%) cases exhibited mild seroma at the donor site during the short-term follow-up, and all of these cases healed soon after the application of local treatment, within a month. Fifteen cases received a skin graft to facilitate wound closure, and four cases had an infection of the skin graft area. Major complications, such as severe infection and fistula, which would affect functional recovery at both the donor and recipient site, did not appear during the short- or long-term follow-up.
Most of the patients were satisfied with their oral and facial appearance and function during follow-ups; however, a few patients underwent subsequent adjuvant therapy, like radiotherapy and chemotherapy, or experienced tumour relapse, which affected their daily lives. The quality of life at the 1-year follow-up of the 252 oral SCC patients who received free ALT transfers without radiotherapy/chemotherapy or recurrence/metastasis is summarized in Table 5 .
| Location | No. | Long-term complications | Cosmetic appearance | Diet | Speech |
|---|---|---|---|---|---|
| Tongue | 102 | Recipient site deformity n = 2 |
Good n = 88 |
Normal n = 90 |
Fluent and intelligible n = 77 |
| Donor site deformity n = 0 |
Satisfactory n = 10 |
Soft n = 11 |
Intelligible with effort n = 23 |
||
| Unsatisfactory n = 4 |
Liquid n = 1 |
Unintelligible n = 2 |
|||
| Cheek | 56 | Recipient site deformity n = 1 |
Good n = 30 |
Normal n = 53 |
Fluent and intelligible n = 50 |
| Donor site deformity n = 0 |
Satisfactory n = 20 |
Soft n = 3 |
Intelligible with effort n = 6 |
||
| Unsatisfactory n = 6 |
Liquid n = 0 |
Unintelligible n = 0 |
|||
| Gingiva | 46 | Recipient site deformity n = 1 |
Good n = 35 |
Normal n = 32 |
Fluent and intelligible n = 39 |
| Donor site deformity n = 0 |
Satisfactory n = 10 |
Soft n = 12 |
Intelligible with effort n = 7 |
||
| Unsatisfactory n = 1 |
Liquid n = 2 |
Unintelligible n = 0 |
|||
| Floor of the mouth | 19 | Recipient site deformity n = 0 |
Good n = 15 |
Normal n = 11 |
Fluent and intelligible n = 10 |
| Donor site deformity n = 0 |
Satisfactory n = 4 |
Soft n = 5 |
Intelligible with effort n = 7 |
||
| Unsatisfactory n = 0 |
Liquid n = 3 |
Unintelligible n = 2 |
|||
| Palate | 16 | Recipient site deformity n = 0 |
Good n = 13 |
Normal n = 14 |
Fluent and intelligible n = 13 |
| Donor site deformity n = 0 |
Satisfactory n = 3 |
Soft n = 2 |
Intelligible with effort n = 3 |
||
| Unsatisfactory n = 0 |
Liquid n = 0 |
Unintelligible n = 0 |
|||
| Oropharynx | 13 | Recipient site deformity n = 1 |
Good n = 8 |
Normal n = 8 |
Fluent and intelligible n = 7 |
| Donor site deformity n = 0 |
Satisfactory n = 4 |
Soft n = 4 |
Intelligible with effort n = 5 |
||
| Unsatisfactory n = 1 |
Liquid n = 1 |
Unintelligible n = 1 |
|||
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