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The anterolateral thigh free flap for skull base reconstruction
Otolaryngology–Head and Neck Surgery (2009) 140, 855-860
ORIGINAL RESEARCH—SKULL BASE SURGERY
The anterolateral thigh free flap for skull base reconstruction Matthew M. Hanasono, MD, Justin M. Sacks, MD, Neha Goel, BS, Martina Ayad, BS, and Roman J. Skoracki, MD, Houston, TX No sponsorships or competing interests have been disclosed for this article. ABSTRACT OBJECTIVE: To assess outcomes of patients undergoing reconstruction after resection of skull base tumors with the anterolateral thigh (ALT) free flap. STUDY DESIGN: Case series with chart review. SUBJECTS AND METHODS: Thirty-four consecutive patients with cancers involving the skull base that underwent reconstruction with the ALT free flap between 2005 and 2008 were reviewed. RESULTS: The ALT free flap was successfully used to reconstruct two, five, and 17 anterior, lateral, and posterior skull base defects, respectively. In addition, six and four combined anteriorlateral and lateral-posterior defects, respectively, were reconstructed. The overall complication rate was 29 percent. There were no flap losses. Nerve grafts (n ⫽ 6) and fascial slings (n ⫽ 14) for facial reanimation were performed using the lateral femoral cutaneous nerve and fascia lata from the same donor site as the ALT free flap. By harvesting the flap and graft(s) simultaneously with the resection, an average of 3.0 hours per case was saved. CONCLUSIONS: The ALT free flap is a versatile, reliable flap that should be considered a first-line option for skull base reconstruction. Operative time is minimized by performing a simultaneous two-team approach to resection and reconstruction, and by harvesting nerve, vein, and fascial grafts from the same donor site as the flap. © 2009 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved.
R
esection of skull base tumors may result in exposed dura, cranial bone, and neurovascular structures. Reconstruction of these defects is often mandatory to prevent life-threatening complications, such as vascular rupture, meningitis, and osteomyelitis, as well as to restore craniofacial form and function. Local and regional flaps have limited indications due to their small size, restricted reach, and inferior cosmesis.1 In recent years, free tissue transfer has become the preferred method of reconstruction for skull base defects due to reliable healing and a low rate of complications.1-3 Although multiple free flaps have been
described for skull base reconstruction, most reports to date have favored the rectus abdominis free flap due to its versatility, reliability, and location, which facilitates a simultaneous two-team approach to reconstruction and tumor resection.1-6 In the present study, we sought to evaluate our outcomes with the anterolateral thigh (ALT) free flap for reconstruction of skull base defects. The ALT free flap has been shown to be a very useful flap for oral and pharyngeal reconstructions and has more recently been suggested as an option for skull base reconstruction.7-9 Based on our more extensive experience than previously reported, we discuss our rationale for selecting the ALT free flap as a first-line choice to reconstruct a broad spectrum of skull base defects. We describe technical details on how to apply this flap specifically to reconstruction of skull base defects and demonstrate how harvest of additional tissues, such as nerve grafts and fascial grafts, which are often indicated in the comprehensive treatment of skull base diseases, from the same donor site results in significant operative time savings and reduced donor site morbidity.
METHODS A case series with chart review was performed of patients undergoing immediate skull base reconstruction following oncologic resection using the ALT free flap performed at The University of Texas M. D. Anderson Cancer Center between July 2004 and June 2008. All reconstructions were performed by the authors (M.M.H. and R.J.S.). Institutional review board approval was obtained prior to undertaking this study. In our series, the defect location was categorized according to the classification system previously described by Irish et al.10 Briefly, region I refers to anterior fossa defects, which result from resections involving the orbital roof and superior nasal cavity in the region of the cribriform plate and frontal sinuses. Region II defects occur laterally and primarily involve the infratemporal and pterygopalatine fos-
Received September 10, 2008; revised January 14, 2009; accepted February 20, 2009.
0194-5998/$36.00 © 2009 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved. doi:10.1016/j.otohns.2009.02.025
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sae and communicate with the middle cranial fossa. Region III defects arise posteriorly, within or around the temporal bone, and extend intracranially into the middle or posterior cranial fossae. The technique for ALT free flap harvest has been described previously.11-14 Whenever practical, a simultaneous two-team approach was used in which the flap was harvested during the resection. Saphenous vein grafts, harvested from the same donor site incision as the ALT free flap, were used when the vascular pedicle length was inadequate to reach recipient vessels. The flaps were designed to include variable amounts of vastus lateralis muscle as needed to fill dead space and create a seal around cranial defects with exposed dura. When multiple defects were present, the ALT free flap can usually be separated into two distinct skin paddles based on separate vascular perforators.13,14 In cases where there was only one cutaneous perforator but more than one skin paddle was needed, the intervening segment of skin was de-epithelialized. In addition to soft tissue free flap reconstruction, various procedures for facial nerve reconstruction and rehabilitation were performed simultaneously or in a delayed manner in patients who underwent a facial nerve excision as part of their oncologic resection. Whenever a functioning facial nerve was sacrificed during the resection or facial nerve paralysis was not present for longer than 12 months, the facial nerve was reconstructed using cable nerve grafts as long as the proximal and distal ends could be located. When facial nerve paralysis existed preoperatively, the patient was evaluated for brow ptosis, ectropion, incomplete eye closure, and facial asymmetry. Patients then underwent one or more of the following procedures as indicated for facial nerve rehabilitation: direct browlift, lateral canthoplasty, upper eyelid gold weight placement, and static reanimation with a fascial sling. When there was no pre-existing facial paralysis, but the nerve was sacrificed during the oncologic resection, a fascial sling was placed to immediately improve facial symmetry and oral competence, regardless of whether nerve grafting was performed.15,16 Direct browlifts, lateral canthoplasties, and upper eyelid gold weight placements were performed as a secondary procedure depending on the postoperative function and appearance of the patient as described by Golio et al.17 The lateral femoral cutaneous nerve was harvested as a nerve graft through the same incision as the ALT free flap (Fig 1A). The nerve is located superficial to the fascia lata within the deep subcutaneous fat. It arises within 2 cm of the anterior superior iliac spine and travels toward the knee, usually dividing into several branches distally. More than 20 cm of nerve can be obtained for use as a graft. In cases where a fascial sling was placed, fascia lata was also harvested from the same incision as the ALT free flap harvest (Fig 1B). A strip of fascia 1 to 2 cm wide was harvested and split into two slips distally. The slips were secured to the modiolus at the oral commissure and the nasolabial crease
Figure 1 (A) Lateral femoral cutaneous nerve graft harvest during flap dissection. (B) Tensor fascia lata graft harvest via the same incision.
or nasal alar region and the other end of the fascial graft was secured under tension to the periosteum of the zygoma. All patients were routinely admitted to the intensive care unit postoperatively for monitoring and ventilatory support. Mechanical ventilation was weaned as tolerated on the first postoperative day.
RESULTS During the study period, 34 patients (25 male and nine female) underwent skull base reconstruction using the ALT free flap following oncologic resection. The mean age was 64.2 years (range, 14 to 90 years; standard deviation, 17.0 years). The mean follow-up time was 8.4 months (range, 3.0 to 34.0 months; standard deviation, 8.2 months). Tumors included squamous cell carcinoma (n ⫽ 19), basal cell carcinoma (n ⫽ 5), sarcoma (n ⫽ 5), sebaceous cell carcinoma (n ⫽ 1), and acinic cell carcinoma (n ⫽ 1). Eighteen patients received external beam radiation therapy, including eight patients who received preoperative radiation therapy and 10 patients who received postoperative radiation therapy. Defect locations are summarized in Table 1. The average flap size was 138.7 cm2 (range, 49 cm2 to 410 cm2; standard
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The anterolateral thigh free flap for skull . . .
Table 1 Oncologic defect details in patients undergoing skull base reconstruction with the anterolateral thigh free flap Defect Location Region I Region II Region III Region II⫹III Region I⫹II Dural repair Facial nerve resection
No. (%)
2 5 17 4 6 3 14
(5.9) (14.7) (50.0) (11.7) (17.6) (8.8) (41.2)
n ⫽ 34 patients.
deviation, 88.2 cm2). Twenty-eight flaps were myocutaneous while six flaps were fasciocutaneous. Three alloplastic cranioplasties and one autogenous bone graft were used for calvarial reconstruction. Dural defects were repaired by a neurosurgeon using allografts. A representative middle skull base defect (region II) and reconstruction is shown in Figure 2. An ALT free flap with two separate skin paddles based on separate branches from the main vascular pedicle was used to reconstruct this defect. A fascial sling and right upper eyelid gold weight were also placed for facial nerve rehabilitation. A representative posterior skull base (region III) defect is shown in Figure 3. A separate medial cheek
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basal cell carcinoma was also excised. An ALT free flap was used to reconstruct the defect and a fascial sling was used to suspend the right nasolabial region and oral commissure to the zygomatic periosteum. The facial nerve was reconstructed using cable nerve grafts from the lateral femoral cutaneous nerve. A right direct brow lift, right upper eyelid gold weight placement, and right lateral canthoplasty were also performed. In addition to free flap reconstruction, various other procedures were performed for facial nerve reconstruction or rehabilitation in 18 patients (Table 2). Saphenous vein grafts were harvested from the same donor thigh via the same incision used for harvesting the ALT free flap in cases of inadequate pedicle length in three patients. Six patients underwent a delayed flap revision for improvement of contour no sooner than six months following the initial reconstruction or the completion of postoperative radiation therapy, if given, whichever was later, in order to allow for complete healing and spontaneous flap remodeling. Operative times, intensive care unit stays, and hospital stays are summarized in Table 3. It should be noted that reconstructive operative times include not only performing ALT free flap reconstruction but also a variable number of other procedures related to facial nerve reconstruction or rehabilitation. Individual operative times for each surgeon involved (ablative and reconstructive) were available for the most recent 24 cases. Fourteen of these cases were performed using a two-team approach in which free flap har-
Figure 2 (A) A region II defect, showing exposed dura (arrow), in a 13-year-old with rhabdomyosarcoma. (B) The patient four months postoperatively.
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Figure 3
(A) A region III defect in a 53-year-old with basal cell carcinoma. (B) The patient nine months postoperatively.
vest, as well as nerve, fascia, and vein graft harvest if needed, were performed simultaneously with the oncologic resection. The mean time needed to perform the reconstructive surgery in these 14 cases was 6.6 hours, with a mean of 3.6 hours of time needed for the reconstructive surgery after the oncologic resection was complete. This resulted in a mean time savings in operating room time of 3.0 hours (standard deviation, 0.27 hours) using the two-team approach. Complications are listed in Table 4. There were no free flap losses. There were no mortalities during the immediate postoperative period (within 30 days). Preoperative or postoperative radiation therapy was not associated with a significant increase in flap recipient site complications (P ⫽ 0.67 using the 2 test), although five of six patients with recipient site complications received radiation therapy. All
Table 2 Reconstructive procedures performed in addition to anterolateral thigh free flap reconstruction of skull base defects Procedure Nerve graft Fascial graft Upper eyelid gold weight placement Ectropion repair Browlift n ⫽ 34 patients.
patients recovered their previous level of activity and no patient had gait disturbance after ALT free flap harvest. All patients had decreased sensation in the area of the anterior thigh on the side from which the ALT free flap was harvested.
DISCUSSION The ALT free flap was shown to be extremely versatile in this series, in which it was used to reconstruct anterior, lateral, and posterior skull base defects. The vascular anatomy of this flap is variable but often includes more than one perforating blood vessel coming from the main pedicle.13,14 This allows reconstruction with multiple independent skin
Table 3 Operative times, ICU and hospital stay in patients undergoing skull base reconstruction with the anterolateral thigh free flap Mean Time Range SD
No. (%) 6 14 6 4 3
(17.6) (41.2) (17.6) (11.8) (8.8)
Total operative time (hours) Total reconstruction time (hours) ICU stay (days) Hospital stay (days)
10.8 6.7-18.4 3.2 5.7 3.5-10.0 1.5 2.8 1-5 1.4 9.6 4-33 5.9
ICU, intensive care unit; n ⫽ 34 patients.
Hanasono et al
The anterolateral thigh free flap for skull . . .
Table 4 Complications in patients undergoing skull base reconstruction with the anterolateral thigh free flap Complication Recipient site Cerebrospinal fluid leak Nasocutaneous fistula Orocutaneous fistula Wound infection Donor site Dehiscence Seroma Total*
No. (%)
1 1 1 3
(3) (3) (3) (9)
2 (6) 2 (6) 10 (29)
*No patient had more than one complication; n ⫽ 34 patients.
paddles, which we found particularly useful for reconstructing region II defects. In these reconstructions, one paddle can be used to reconstruct the anterior facial skin or the orbit, and a second paddle is used to reconstruct the palate, isolating the oral cavity from the sinonasal cavity. Additional surfaces, such as the lateral nasal wall, can be resurfaced with skin if a third perforator is present or a bridge of ALT free flap can be de-epithelialized to allow for folding of the flap. However, we have found that leaving exposed muscle, fat, or fascia in the lateral nasal region does not result in complications such as fistula, infection, or mucocele formation, and that these tissues rapidly remucosalize. For deep defects requiring bulk to restore craniofacial contour, or defects in which dural or other critical neurovascular structures needed coverage, a variable amount of the vastus lateralis muscle was included with the fascial and skin components of the flap. As with other series, most bony defects were not reconstructed with rigid material in our series.4,18 Whenever possible, we attempted to close flap tissue around skull base bony defects, but in many cases, it was not possible to suture circumferentially around exposed dura as there was a paucity of soft tissue in the region immediately adjacent to which to sew the flap. We have found that placing well-vascularized muscle from the free flap over such defects under mild compression results in an adequate seal. By doing so, we did not observe any complications of meningitis, brain abscess, or pneumocephalus in our series. The ALT free flap was used to reconstruct defects as small as 49 cm2 and as large as 410 cm2 in our series. For limited defects, the ALT free flap can be harvested as a cutaneous or fasciocutaneous perforator flap and thinned aggressively, replacing the radial forearm fasciocutaneous free flap in many centers.11-13 For more extensive defects, a flap up to 8 to 10 centimeters wide can usually be harvested and the thigh wound closed primarily.14 For very large defects, ALT free flaps up to 16 cm wide by 40 cm long supported by the vascular pedicle (descending branch of the lateral circumflex femoral artery and vein) have been re-
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ported.19 In these cases, the donor site is skin grafted. Skin grafting the ALT free flap donor site is less morbid and deforming than skin grafting the rectus abdominis myocutaneous free flap donor site and demonstrates more reliable graft take than the latissimus dorsi myocutaneous free flap donor site. In addition, a greater amount of fascia is available from the thigh, which does not need fascial reconstruction after flap harvest, than from the abdomen, in which harvest of more than a few centimeters of fascia results in a risk for hernia or bulge and usually necessitates closure with mesh. Subjectively, we have also found that inclusion of greater amounts of subcutaneous fibrofatty tissue from the thigh results in less postoperative atrophy of the flap as compared to many of our earlier reconstructions with latissimus dorsi or rectus abdominis myocutaneous free flaps in which the muscle component makes up a greater amount of the flap bulk. There were no flap losses in this series, emphasizing the reliability of this flap, which includes a pedicle of generous caliber, and one or more robust perforating vessels to the skin island. Partial or total flap losses may have significant implications in skull base reconstructions, potentially resulting in dural exposure, cerebrospinal fluid (CSF) leaks, meningitis, cranial bone osteomyelitis, and the need for additional surgery.3 In addition, flap losses may delay adjuvant chemotherapy and/or radiation therapy, decreasing the patient’s chance of cure. Our overall rate of complications (29%) was comparable to other series, which have suggested an overall surgical complication rate of 25 percent to 60 percent.2,4,5,9,20 Cerebrospinal fluid leak is among the most common complications reported in other series with a 5 percent to 21 percent incidence.5,20 We encountered one CSF leak in our study (3% incidence), which resolved with lumbar drainage. In contrast to other reports, we did not observe a significant effect of radiation therapy on recipient site complications.5 There were six patients with donor site complications, all of which resolved with conservative treatment and did not require further surgery. We have shown that the simultaneous two-team approach saves a considerable amount of operative time (mean of 3.0 hours) in long cases that averaged 10.8 hours in our series, which is important in terms of surgeon fatigue, operating room costs, and, most importantly, patient morbidity. We have found that the increased distance of the lower extremity, compared to the abdomen, from the head and neck gives the resecting team and the reconstructive team more room to operate simultaneously. In general, we usually experience difficulty with harvesting flaps located in the upper extremity or back simultaneously with the resection due to proximity to the resecting team and limitations of patient positioning. In cases in which facial nerve reconstruction and rehabilitation is indicated, soft tissue reconstruction with the ALT free flap is also attractive because nerve graft harvest for cable nerve grafting and fascial graft harvest for static facial reanimation can be performed through the same in-
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cision, again minimizing operative time as well as donor site morbidity. We favor performing procedures such as cable nerve grafting and placement of facial slings at the time of the resection since they are fraught with the potential for complications when performed in a delayed manner after radiation therapy has been administered. Additionally, when the vascular pedicle length of the flap is insufficient to reach the recipient vessels, the saphenous vein can be harvested from the medial thigh through the same donor site incision as the ALT free flap, also saving operative time and sparing the patient the morbidity of an additional skin incision. The availability of nerve grafts, fascial grafts, and vein grafts from the thigh donor site, which are frequently indicated in the treatment of postablative skull base defects as shown in our series, contributes to the ALT free flap becoming our flap of choice in patients with skull base tumors.
CONCLUSION Because of its superior reliability, versatility, and ability to be harvested simultaneously with the resection using a two-team approach to reduce operative time, we feel that the ALT free flap is the reconstructive method of choice for most skull base reconstructions, particularly those that are complicated or extensive. An additional advantage of this flap is that nerve, fascial, and vein grafts can be harvested from the same donor site incision when needed, again minimizing valuable operative time as well as patient morbidity.
AUTHOR INFORMATION From the Department of Plastic Surgery, The University of Texas M. D. Anderson Cancer Center. Corresponding author: Matthew M. Hanasono, MD, 1515 Holcombe Blvd. Unit 443, Houston, TX 77030. E-mail address: [email protected]. Presented at the Annual Meeting of the American Academy of Otolaryngology–Head and Neck Surgery, Chicago, IL, September 21-24, 2008.
AUTHOR CONTRIBUTIONS Matthew M. Hanasono, manuscript preparation, data acquisition and analysis; Justin M. Sacks, manuscript preparation, data acquisition and analysis; Neha Goel, data acquisition; Martina Ayad, data acquisition; Roman J. Skoracki, manuscript preparation, data acquisition and analysis.
DISCLOSURES Competing interests: None. Sponsorships: None.
REFERENCES 1. Chang DW, Langstein HN, Gupta A, et al. Reconstructive management of cranial base defects after tumor ablation. Plast Reconstr Surg 2001;107:1346 –55. 2. Urken ML, Catalano PJ, Sen C, et al. Free tissue transfer for skull base reconstruction: analysis of complications and a classification scheme for defining skull base defects. Arch Otolaryngol Head Neck Surg 1993;119:1318 –25. 3. Neligan PC, Mulholland S, Irish J, et al. Flap selection in cranial base reconstruction. Plast Reconstr Surg 1996;98:1159 – 66. 4. Disa JJ, Rodriguez VM, Cordeiro PG. Reconstruction of lateral skull base oncological defects: the role of free tissue transfer. Ann Plast Surg 1998;41:633–9. 5. Teknos TN, Smith JC, Day TA, et al. Microvascular free tissue transfer in reconstructing skull base defects: lessons learned. Laryngoscope 2002;112:1871– 6. 6. Chiu ES, Kraus D, Bui DT, et al. Anterior and middle cranial fossa skull base reconstruction using microvascular free tissue techniques. Ann Plast Surg 2008;60:514 –20. 7. Amin A, Rifaat M, Civantos F, et al. Free anterolateral thigh flap for reconstruction of major craniofacial defects. J Reconstr Microsurg 2006;22:97–104. 8. Malata CM, Terhani H, Kumiponjera D, et al. Use of anterolateral thigh and lateral arm fasciocutaneous free flaps in lateral skull base reconstruction. Ann Plast Surg 2006;57:169 –75. 9. Rosenthal EL, King T, McGrew BM, et al. Evolution of a paradigm for free tissue transfer reconstruction of lateral temporal bone defects. Head Neck 2008;30:589 –94. 10. Irish J, Gullane PJ, Gentili F, et al. Tumors of the skull base: outcome and survival analysis of 77 cases. Head Neck 1994;16:3–10. 11. Koshima I, Fukuda H, Utunomiya R, et al. The anterolateral thigh flap: variations in its vascular pedicle. Br J Plast Surg 1989;42:260 –2. 12. Kimata Y, Uchiyama K, Ebihara S, et al. Anatomic variations and technical problems of the anterolateral thigh flap: a report of 74 cases. Plast Reconstr Surg 1998;102:1517–23. 13. Wei FC, Jain V, Celik N, et al. Free anterolateral thigh flap for reconstruction of head and neck defects following cancer ablation. Plast Reconstr Surg 2000;105:2349 – 60. 14. Yu P. Characteristics of the anterolateral thigh flap in a Western population and its application in head and neck reconstruction. Head Neck 2004;26:1038 – 44. 15. Deleyiannis FWB, Askari M, Schmidt KL, et al. Muscle activity in the partially paralyzed face after placement of a fascial sling: a preliminary report. Ann Plast Surg 2005;55:449 –55. 16. Rose EH. Autogenous fascia lata grafts: clinical applications in reanimation of the totally or partially paralyzed face. Plast Reconstr Surg 2005;116:20 –32. 17. Golio D, De Matelaere S, Anderson J, et al. Outcomes of periocular reconstruction for facial nerve paralysis in cancer patients. Plast Reconstr Surg 2007;119:1233–7. 18. Spinelli HM, Persing JA, Walser B. Reconstruction of the cranial base. Clin Plast Surg 1995;22:555– 61. 19. Mosahebi A, Disa JJ, Pusic AL, et al. The use of the extended anterolateral thigh flap for reconstruction of massive oncologic defects. Plast Reconstr Surg 2008;122:492– 6. 20. Chepeha DB, Wang SJ, Marentette LJ, et al. Radial forearm free tissue transfer reduces complications in salvage skull base surgery. Otolaryngol Head Neck Surg 2004;131:958 – 63.
ORIGINAL RESEARCH—SKULL BASE SURGERY
The anterolateral thigh free flap for skull base reconstruction Matthew M. Hanasono, MD, Justin M. Sacks, MD, Neha Goel, BS, Martina Ayad, BS, and Roman J. Skoracki, MD, Houston, TX No sponsorships or competing interests have been disclosed for this article. ABSTRACT OBJECTIVE: To assess outcomes of patients undergoing reconstruction after resection of skull base tumors with the anterolateral thigh (ALT) free flap. STUDY DESIGN: Case series with chart review. SUBJECTS AND METHODS: Thirty-four consecutive patients with cancers involving the skull base that underwent reconstruction with the ALT free flap between 2005 and 2008 were reviewed. RESULTS: The ALT free flap was successfully used to reconstruct two, five, and 17 anterior, lateral, and posterior skull base defects, respectively. In addition, six and four combined anteriorlateral and lateral-posterior defects, respectively, were reconstructed. The overall complication rate was 29 percent. There were no flap losses. Nerve grafts (n ⫽ 6) and fascial slings (n ⫽ 14) for facial reanimation were performed using the lateral femoral cutaneous nerve and fascia lata from the same donor site as the ALT free flap. By harvesting the flap and graft(s) simultaneously with the resection, an average of 3.0 hours per case was saved. CONCLUSIONS: The ALT free flap is a versatile, reliable flap that should be considered a first-line option for skull base reconstruction. Operative time is minimized by performing a simultaneous two-team approach to resection and reconstruction, and by harvesting nerve, vein, and fascial grafts from the same donor site as the flap. © 2009 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved.
R
esection of skull base tumors may result in exposed dura, cranial bone, and neurovascular structures. Reconstruction of these defects is often mandatory to prevent life-threatening complications, such as vascular rupture, meningitis, and osteomyelitis, as well as to restore craniofacial form and function. Local and regional flaps have limited indications due to their small size, restricted reach, and inferior cosmesis.1 In recent years, free tissue transfer has become the preferred method of reconstruction for skull base defects due to reliable healing and a low rate of complications.1-3 Although multiple free flaps have been
described for skull base reconstruction, most reports to date have favored the rectus abdominis free flap due to its versatility, reliability, and location, which facilitates a simultaneous two-team approach to reconstruction and tumor resection.1-6 In the present study, we sought to evaluate our outcomes with the anterolateral thigh (ALT) free flap for reconstruction of skull base defects. The ALT free flap has been shown to be a very useful flap for oral and pharyngeal reconstructions and has more recently been suggested as an option for skull base reconstruction.7-9 Based on our more extensive experience than previously reported, we discuss our rationale for selecting the ALT free flap as a first-line choice to reconstruct a broad spectrum of skull base defects. We describe technical details on how to apply this flap specifically to reconstruction of skull base defects and demonstrate how harvest of additional tissues, such as nerve grafts and fascial grafts, which are often indicated in the comprehensive treatment of skull base diseases, from the same donor site results in significant operative time savings and reduced donor site morbidity.
METHODS A case series with chart review was performed of patients undergoing immediate skull base reconstruction following oncologic resection using the ALT free flap performed at The University of Texas M. D. Anderson Cancer Center between July 2004 and June 2008. All reconstructions were performed by the authors (M.M.H. and R.J.S.). Institutional review board approval was obtained prior to undertaking this study. In our series, the defect location was categorized according to the classification system previously described by Irish et al.10 Briefly, region I refers to anterior fossa defects, which result from resections involving the orbital roof and superior nasal cavity in the region of the cribriform plate and frontal sinuses. Region II defects occur laterally and primarily involve the infratemporal and pterygopalatine fos-
Received September 10, 2008; revised January 14, 2009; accepted February 20, 2009.
0194-5998/$36.00 © 2009 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved. doi:10.1016/j.otohns.2009.02.025
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Otolaryngology–Head and Neck Surgery, Vol 140, No 6, June 2009
sae and communicate with the middle cranial fossa. Region III defects arise posteriorly, within or around the temporal bone, and extend intracranially into the middle or posterior cranial fossae. The technique for ALT free flap harvest has been described previously.11-14 Whenever practical, a simultaneous two-team approach was used in which the flap was harvested during the resection. Saphenous vein grafts, harvested from the same donor site incision as the ALT free flap, were used when the vascular pedicle length was inadequate to reach recipient vessels. The flaps were designed to include variable amounts of vastus lateralis muscle as needed to fill dead space and create a seal around cranial defects with exposed dura. When multiple defects were present, the ALT free flap can usually be separated into two distinct skin paddles based on separate vascular perforators.13,14 In cases where there was only one cutaneous perforator but more than one skin paddle was needed, the intervening segment of skin was de-epithelialized. In addition to soft tissue free flap reconstruction, various procedures for facial nerve reconstruction and rehabilitation were performed simultaneously or in a delayed manner in patients who underwent a facial nerve excision as part of their oncologic resection. Whenever a functioning facial nerve was sacrificed during the resection or facial nerve paralysis was not present for longer than 12 months, the facial nerve was reconstructed using cable nerve grafts as long as the proximal and distal ends could be located. When facial nerve paralysis existed preoperatively, the patient was evaluated for brow ptosis, ectropion, incomplete eye closure, and facial asymmetry. Patients then underwent one or more of the following procedures as indicated for facial nerve rehabilitation: direct browlift, lateral canthoplasty, upper eyelid gold weight placement, and static reanimation with a fascial sling. When there was no pre-existing facial paralysis, but the nerve was sacrificed during the oncologic resection, a fascial sling was placed to immediately improve facial symmetry and oral competence, regardless of whether nerve grafting was performed.15,16 Direct browlifts, lateral canthoplasties, and upper eyelid gold weight placements were performed as a secondary procedure depending on the postoperative function and appearance of the patient as described by Golio et al.17 The lateral femoral cutaneous nerve was harvested as a nerve graft through the same incision as the ALT free flap (Fig 1A). The nerve is located superficial to the fascia lata within the deep subcutaneous fat. It arises within 2 cm of the anterior superior iliac spine and travels toward the knee, usually dividing into several branches distally. More than 20 cm of nerve can be obtained for use as a graft. In cases where a fascial sling was placed, fascia lata was also harvested from the same incision as the ALT free flap harvest (Fig 1B). A strip of fascia 1 to 2 cm wide was harvested and split into two slips distally. The slips were secured to the modiolus at the oral commissure and the nasolabial crease
Figure 1 (A) Lateral femoral cutaneous nerve graft harvest during flap dissection. (B) Tensor fascia lata graft harvest via the same incision.
or nasal alar region and the other end of the fascial graft was secured under tension to the periosteum of the zygoma. All patients were routinely admitted to the intensive care unit postoperatively for monitoring and ventilatory support. Mechanical ventilation was weaned as tolerated on the first postoperative day.
RESULTS During the study period, 34 patients (25 male and nine female) underwent skull base reconstruction using the ALT free flap following oncologic resection. The mean age was 64.2 years (range, 14 to 90 years; standard deviation, 17.0 years). The mean follow-up time was 8.4 months (range, 3.0 to 34.0 months; standard deviation, 8.2 months). Tumors included squamous cell carcinoma (n ⫽ 19), basal cell carcinoma (n ⫽ 5), sarcoma (n ⫽ 5), sebaceous cell carcinoma (n ⫽ 1), and acinic cell carcinoma (n ⫽ 1). Eighteen patients received external beam radiation therapy, including eight patients who received preoperative radiation therapy and 10 patients who received postoperative radiation therapy. Defect locations are summarized in Table 1. The average flap size was 138.7 cm2 (range, 49 cm2 to 410 cm2; standard
Hanasono et al
The anterolateral thigh free flap for skull . . .
Table 1 Oncologic defect details in patients undergoing skull base reconstruction with the anterolateral thigh free flap Defect Location Region I Region II Region III Region II⫹III Region I⫹II Dural repair Facial nerve resection
No. (%)
2 5 17 4 6 3 14
(5.9) (14.7) (50.0) (11.7) (17.6) (8.8) (41.2)
n ⫽ 34 patients.
deviation, 88.2 cm2). Twenty-eight flaps were myocutaneous while six flaps were fasciocutaneous. Three alloplastic cranioplasties and one autogenous bone graft were used for calvarial reconstruction. Dural defects were repaired by a neurosurgeon using allografts. A representative middle skull base defect (region II) and reconstruction is shown in Figure 2. An ALT free flap with two separate skin paddles based on separate branches from the main vascular pedicle was used to reconstruct this defect. A fascial sling and right upper eyelid gold weight were also placed for facial nerve rehabilitation. A representative posterior skull base (region III) defect is shown in Figure 3. A separate medial cheek
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basal cell carcinoma was also excised. An ALT free flap was used to reconstruct the defect and a fascial sling was used to suspend the right nasolabial region and oral commissure to the zygomatic periosteum. The facial nerve was reconstructed using cable nerve grafts from the lateral femoral cutaneous nerve. A right direct brow lift, right upper eyelid gold weight placement, and right lateral canthoplasty were also performed. In addition to free flap reconstruction, various other procedures were performed for facial nerve reconstruction or rehabilitation in 18 patients (Table 2). Saphenous vein grafts were harvested from the same donor thigh via the same incision used for harvesting the ALT free flap in cases of inadequate pedicle length in three patients. Six patients underwent a delayed flap revision for improvement of contour no sooner than six months following the initial reconstruction or the completion of postoperative radiation therapy, if given, whichever was later, in order to allow for complete healing and spontaneous flap remodeling. Operative times, intensive care unit stays, and hospital stays are summarized in Table 3. It should be noted that reconstructive operative times include not only performing ALT free flap reconstruction but also a variable number of other procedures related to facial nerve reconstruction or rehabilitation. Individual operative times for each surgeon involved (ablative and reconstructive) were available for the most recent 24 cases. Fourteen of these cases were performed using a two-team approach in which free flap har-
Figure 2 (A) A region II defect, showing exposed dura (arrow), in a 13-year-old with rhabdomyosarcoma. (B) The patient four months postoperatively.
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Figure 3
(A) A region III defect in a 53-year-old with basal cell carcinoma. (B) The patient nine months postoperatively.
vest, as well as nerve, fascia, and vein graft harvest if needed, were performed simultaneously with the oncologic resection. The mean time needed to perform the reconstructive surgery in these 14 cases was 6.6 hours, with a mean of 3.6 hours of time needed for the reconstructive surgery after the oncologic resection was complete. This resulted in a mean time savings in operating room time of 3.0 hours (standard deviation, 0.27 hours) using the two-team approach. Complications are listed in Table 4. There were no free flap losses. There were no mortalities during the immediate postoperative period (within 30 days). Preoperative or postoperative radiation therapy was not associated with a significant increase in flap recipient site complications (P ⫽ 0.67 using the 2 test), although five of six patients with recipient site complications received radiation therapy. All
Table 2 Reconstructive procedures performed in addition to anterolateral thigh free flap reconstruction of skull base defects Procedure Nerve graft Fascial graft Upper eyelid gold weight placement Ectropion repair Browlift n ⫽ 34 patients.
patients recovered their previous level of activity and no patient had gait disturbance after ALT free flap harvest. All patients had decreased sensation in the area of the anterior thigh on the side from which the ALT free flap was harvested.
DISCUSSION The ALT free flap was shown to be extremely versatile in this series, in which it was used to reconstruct anterior, lateral, and posterior skull base defects. The vascular anatomy of this flap is variable but often includes more than one perforating blood vessel coming from the main pedicle.13,14 This allows reconstruction with multiple independent skin
Table 3 Operative times, ICU and hospital stay in patients undergoing skull base reconstruction with the anterolateral thigh free flap Mean Time Range SD
No. (%) 6 14 6 4 3
(17.6) (41.2) (17.6) (11.8) (8.8)
Total operative time (hours) Total reconstruction time (hours) ICU stay (days) Hospital stay (days)
10.8 6.7-18.4 3.2 5.7 3.5-10.0 1.5 2.8 1-5 1.4 9.6 4-33 5.9
ICU, intensive care unit; n ⫽ 34 patients.
Hanasono et al
The anterolateral thigh free flap for skull . . .
Table 4 Complications in patients undergoing skull base reconstruction with the anterolateral thigh free flap Complication Recipient site Cerebrospinal fluid leak Nasocutaneous fistula Orocutaneous fistula Wound infection Donor site Dehiscence Seroma Total*
No. (%)
1 1 1 3
(3) (3) (3) (9)
2 (6) 2 (6) 10 (29)
*No patient had more than one complication; n ⫽ 34 patients.
paddles, which we found particularly useful for reconstructing region II defects. In these reconstructions, one paddle can be used to reconstruct the anterior facial skin or the orbit, and a second paddle is used to reconstruct the palate, isolating the oral cavity from the sinonasal cavity. Additional surfaces, such as the lateral nasal wall, can be resurfaced with skin if a third perforator is present or a bridge of ALT free flap can be de-epithelialized to allow for folding of the flap. However, we have found that leaving exposed muscle, fat, or fascia in the lateral nasal region does not result in complications such as fistula, infection, or mucocele formation, and that these tissues rapidly remucosalize. For deep defects requiring bulk to restore craniofacial contour, or defects in which dural or other critical neurovascular structures needed coverage, a variable amount of the vastus lateralis muscle was included with the fascial and skin components of the flap. As with other series, most bony defects were not reconstructed with rigid material in our series.4,18 Whenever possible, we attempted to close flap tissue around skull base bony defects, but in many cases, it was not possible to suture circumferentially around exposed dura as there was a paucity of soft tissue in the region immediately adjacent to which to sew the flap. We have found that placing well-vascularized muscle from the free flap over such defects under mild compression results in an adequate seal. By doing so, we did not observe any complications of meningitis, brain abscess, or pneumocephalus in our series. The ALT free flap was used to reconstruct defects as small as 49 cm2 and as large as 410 cm2 in our series. For limited defects, the ALT free flap can be harvested as a cutaneous or fasciocutaneous perforator flap and thinned aggressively, replacing the radial forearm fasciocutaneous free flap in many centers.11-13 For more extensive defects, a flap up to 8 to 10 centimeters wide can usually be harvested and the thigh wound closed primarily.14 For very large defects, ALT free flaps up to 16 cm wide by 40 cm long supported by the vascular pedicle (descending branch of the lateral circumflex femoral artery and vein) have been re-
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ported.19 In these cases, the donor site is skin grafted. Skin grafting the ALT free flap donor site is less morbid and deforming than skin grafting the rectus abdominis myocutaneous free flap donor site and demonstrates more reliable graft take than the latissimus dorsi myocutaneous free flap donor site. In addition, a greater amount of fascia is available from the thigh, which does not need fascial reconstruction after flap harvest, than from the abdomen, in which harvest of more than a few centimeters of fascia results in a risk for hernia or bulge and usually necessitates closure with mesh. Subjectively, we have also found that inclusion of greater amounts of subcutaneous fibrofatty tissue from the thigh results in less postoperative atrophy of the flap as compared to many of our earlier reconstructions with latissimus dorsi or rectus abdominis myocutaneous free flaps in which the muscle component makes up a greater amount of the flap bulk. There were no flap losses in this series, emphasizing the reliability of this flap, which includes a pedicle of generous caliber, and one or more robust perforating vessels to the skin island. Partial or total flap losses may have significant implications in skull base reconstructions, potentially resulting in dural exposure, cerebrospinal fluid (CSF) leaks, meningitis, cranial bone osteomyelitis, and the need for additional surgery.3 In addition, flap losses may delay adjuvant chemotherapy and/or radiation therapy, decreasing the patient’s chance of cure. Our overall rate of complications (29%) was comparable to other series, which have suggested an overall surgical complication rate of 25 percent to 60 percent.2,4,5,9,20 Cerebrospinal fluid leak is among the most common complications reported in other series with a 5 percent to 21 percent incidence.5,20 We encountered one CSF leak in our study (3% incidence), which resolved with lumbar drainage. In contrast to other reports, we did not observe a significant effect of radiation therapy on recipient site complications.5 There were six patients with donor site complications, all of which resolved with conservative treatment and did not require further surgery. We have shown that the simultaneous two-team approach saves a considerable amount of operative time (mean of 3.0 hours) in long cases that averaged 10.8 hours in our series, which is important in terms of surgeon fatigue, operating room costs, and, most importantly, patient morbidity. We have found that the increased distance of the lower extremity, compared to the abdomen, from the head and neck gives the resecting team and the reconstructive team more room to operate simultaneously. In general, we usually experience difficulty with harvesting flaps located in the upper extremity or back simultaneously with the resection due to proximity to the resecting team and limitations of patient positioning. In cases in which facial nerve reconstruction and rehabilitation is indicated, soft tissue reconstruction with the ALT free flap is also attractive because nerve graft harvest for cable nerve grafting and fascial graft harvest for static facial reanimation can be performed through the same in-
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cision, again minimizing operative time as well as donor site morbidity. We favor performing procedures such as cable nerve grafting and placement of facial slings at the time of the resection since they are fraught with the potential for complications when performed in a delayed manner after radiation therapy has been administered. Additionally, when the vascular pedicle length of the flap is insufficient to reach the recipient vessels, the saphenous vein can be harvested from the medial thigh through the same donor site incision as the ALT free flap, also saving operative time and sparing the patient the morbidity of an additional skin incision. The availability of nerve grafts, fascial grafts, and vein grafts from the thigh donor site, which are frequently indicated in the treatment of postablative skull base defects as shown in our series, contributes to the ALT free flap becoming our flap of choice in patients with skull base tumors.
CONCLUSION Because of its superior reliability, versatility, and ability to be harvested simultaneously with the resection using a two-team approach to reduce operative time, we feel that the ALT free flap is the reconstructive method of choice for most skull base reconstructions, particularly those that are complicated or extensive. An additional advantage of this flap is that nerve, fascial, and vein grafts can be harvested from the same donor site incision when needed, again minimizing valuable operative time as well as patient morbidity.
AUTHOR INFORMATION From the Department of Plastic Surgery, The University of Texas M. D. Anderson Cancer Center. Corresponding author: Matthew M. Hanasono, MD, 1515 Holcombe Blvd. Unit 443, Houston, TX 77030. E-mail address: [email protected]. Presented at the Annual Meeting of the American Academy of Otolaryngology–Head and Neck Surgery, Chicago, IL, September 21-24, 2008.
AUTHOR CONTRIBUTIONS Matthew M. Hanasono, manuscript preparation, data acquisition and analysis; Justin M. Sacks, manuscript preparation, data acquisition and analysis; Neha Goel, data acquisition; Martina Ayad, data acquisition; Roman J. Skoracki, manuscript preparation, data acquisition and analysis.
DISCLOSURES Competing interests: None. Sponsorships: None.
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