A new angle to mandibular reconstruction: The scapular tip free flap

Transcription

1 ORIGINAL ARTICLE A new angle to mandibular reconstruction: The scapular tip free flap John Yoo, MD,* Samuel A. Dowthwaite, MBBS, Kevin Fung, MD, Jason Franklin, MD, Anthony Nichols, MD Department of Otolaryngology Head and Neck Surgery, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada. Accepted 23 March 2012 Published online 29 July 2012 in Wiley Online Library (wileyonlinelibrary.com). DOI /hed ABSTRACT: Background. The purpose of this study was to review our experience with the scapular tip free flap for mandibular reconstruction, describe the surgical approach, and highlight specific clinical applications. Methods. A retrospective review of all patients undergoing oromandibular reconstruction using a scapular tip free flap at the London Health Sciences Centre was undertaken. Patient demographics, surgical data, and early outcomes were collated. Results. Twenty patients were identified. The majority involved mandibular angle and short segment defects (16 of 20). Average length of the segmental defect was 6.2 cm with the longest measuring 8 cm. A single patient required an osteotomy. Six were revision cases. No vein grafts were required. One complete flap failure occurred. Conclusions. The natural scapular angle makes the scapular tip flap ideal for mandibular angle reconstruction. Short bone segments can be harvested with little donor-site morbidity. The long pedicle length may obviate vein grafts. VC 2012 Wiley Periodicals, Inc. Head Neck 35: , 2013 KEY WORDS: scapular tip, mandible, reconstruction, free flap INTRODUCTION Contemporary reconstruction of oromandibular defects usually incorporates osseous free flaps with or without a soft tissue component. Common donor sites include the fibula, iliac crest, radial forearm, and the lateral border of the scapula. Each mandibular reconstruction option has advantages and disadvantages related to the quality of the bone or soft tissue component, specifics of the free tissue transfer, pedicle length, donor site, and general patient morbidity. 1 Important advantages of flaps harvested from the subscapular system are the lack of atherosclerosis in the vascular pedicle compared to extremity flaps, little donor-site morbidity, and the ability to ambulate patients earlier in their postoperative course. 2,3 The scapular tip free flap (STFF) is based on the angular branch of the thoracodorsal artery. The reliability of this free tissue transfer has been demonstrated conclusively in both cadaveric and in vivo dissections. Recently, it has regained popularity as a versatile osseous flap that is useful for midface reconstruction. 4 6 The STFF can be harvested as a stand-alone osseous flap or as part of a complex chimeric osseous/soft tissue free flap. The vascular pattern of the subscapular system provides unparalleled versatility and freedom between the soft tissue and bone. 7 The bone of the scapular tip can be readily harvested to custom fit various defects. The angle of the scapula *Corresponding author: J. Yoo, London Health Science Centre, Department of Otolaryngology Head and Neck Surgery, Schulich School of Medicine & Dentistry, University of Western Ontario, 800 Commissioners Road East, Suite B3-433A, London, Ontario, Canada N6A 5W9. john.yoo@lhsc.on.ca can be positioned to match mandibular angle defects without osteotomies. Small bone segments can be harvested without sacrificing additional bone from the donor site, and leaves little donor site morbidity. The STFF has the additional benefit of increased pedicle length compared to the traditional lateral scapular border osseous flap, iliac crest flap, and fibula flap This facilitates primary revascularization in situations that may have required vein grafting with shorter pedicle length. 11 Thus the STFF possesses many of the advantages of the traditional lateral scapular flap without its inherent drawbacks. 2 Although the value of the lateral scapular border osseous flap for oromandibular reconstruction has been well documented in the literature, the clinical applications of the STFF based on the angular artery are less well defined. We present a series of 20 consecutive patients who were treated with segmental oromandibulectomy and reconstruction with STFF over a 3-year period. The surgical technique, specific clinical applications, and patient outcomes are described. PATIENTS AND METHODS Surgical technique Our preferred surgical technique to identifying the angular artery is by the posterior latissimus dorsi approach to the thoracodorsal pedicle as described below. At the beginning of the operation, the patient is positioned 20 to 30 degrees lateral decubitus on a soft shoulder roll and secured to the bed with straps. This allows table rotation intraoperatively. Before beginning the dissection, appropriate surface landmarks are identified including the scapular tip, posterior border of 980 HEAD & NECK DOI /HED JULY 2013

2 MANDIBLE RECONSTRUCTION WITH SCAPULAR TIP latissimus dorsi, and the muscular triangle. If a skin paddle is not required, the incision is made in the shape of a "lazy-s" to optimize access to the tip, lateral border, and axilla (Figure 1A). The posterior border of latissimus dorsi is then retracted anteriorly immediately identifying the thoracodorsal pedicle (Figure 1B). The latissimus dorsi is then detached from the scapular tip and the teres major from the lateral border. With posterolateral distraction of the scapula, the angular branch of the thoracodorsal is clearly identified. In most cases, the angular artery arises from the thoracodorsal or serratus anterior artery. 7,9,10 Once the angular artery has been identified and protected, the infraspinatus musculature can be divided down to the scapular bone and the appropriate volume of serratus anterior is detached. The osteotomy is performed and the underlying subscapularis and remaining serratus anterior muscles are divided. Retrograde pedicle dissection is then carried out to the subscapular system as required and to improve pedicle length (Figure 1C). In all cases, primary closure of the donor site can be achieved. Gradual shoulder range of motion exercises can begin on the third postoperative day. Patients Approval was obtained from the Research Ethics Board of the University of Western Ontario. As well, specific consents that allow the publication of identifying photographs were obtained from all patients before surgical management. A retrospective review was undertaken of all patients in whom STFFs were used to reconstruct segmental mandibulectomy defects between August 1, 2008, and December 20, Patient demographics, pertinent aspects of the operation, and patient outcomes were collected. FIGURE 1. (A) "Lazy-S" incision for approach to scapular tip free flap (STFF). (B) Posterior border of latissimus dorsi retracted anteriorly to identify the thoracodorsal pedicle. (C) Harvested STFF isolated on thoracodorsal/angular pedicle. RESULTS Twenty consecutive oromandibular resections with STFF reconstructions were performed over a 3-year period at London Health Sciences Centre in London, Ontario, Canada. This included 13 men and 7 women. Ages ranged from 23 to 86 years with a median age of 71 years. In all cases, the ipsilateral scapular tip was harvested; 11 from the right and 9 from the left. For most cases, the intraoral reconstruction was performed using muscle (latissimus dorsi, teres major, or serratus anterior) that was allowed to remucosalize. Patient demographics and clinical data for each patient are provided in Table 1. All composite resections were undertaken for ablation of malignant lesions. In 18 cases, the confirmed pathology was squamous cell carcinoma (SCC), and 2 cases were for sarcomas. Of the 2 patients with sarcomas, 1 had developed a radiation-induced leiomyosarcoma/highgrade osteosarcoma after undergoing radical radiotherapy for treatment of an oropharyngeal SCC 20 years prior. The other patient with osteosarcoma had undergone chemotherapy followed by oromandibular resection with fibula free flap reconstruction 1 year previously. She developed a local recurrence and was treated with salvage surgery and underwent reconstruction with a scapular tip. Fourteen of the 18 patients with SCC had pt4a lesions on final pathological review. Three patients were preoperatively assessed as ct4, but on final pathology were deemed to be either pt2 or pt3. The final patient with SCC was referred with a submandibular nodal recurrence 2 years after surgical management of a tongue malignancy. Preoperative imaging demonstrated a 6-cm mass intimately related to the mandible and the decision was made to perform a segmental resection with no mucosal component. The length of the mandibular defect ranged from 4 cm to 8 cm, with an average of 6.2 cm. Ten cases involved the mandibular angle 6 body 6 ramus, 5 were mandibular body only, 4 involved the parasymphysis/symphysis, and 1 involved the ramus and condyle. Only 1 case for reconstruction of an anterior mandibular defect required HEAD & NECK DOI /HED JULY

3 TABLE 1. Twenty oromandibular reconstructions with scapular tip free flap. Age/Sex Pathology Primary site Mandible defect Pre-op treatment Defect length, cm Osteotomy Donor site Complication Complication details 23/F Osteosarcoma Mandibular ramus Ramus (including condyle) 56/M Leiomyosarcoma / osteosarcoma Angle of mandible / submasseteric space Surgery/CT 4.5 No Right scapular tip No Ramus / angle CRT 6 No Right scapular tip and latissimus dorsi Yes Postoperative donor site hematoma 80/M SCC Submandibular nodal mass (TxN2b) Body Surgery 6 No Left scapular tip No 66/M SCC Mandibular alveolus (T4aN2b) Body and angle None 8 No Left scapular tip and latissimus dorsi No 84/F SCC Mandibular alveolus (T4aN1) Body None 6 No Left scapular tip No 71/F SCC Mandibular alveolus (T2N0) Body Surgery 5 No Left scapular tip No 81/F SCC Mandibular alveolus (T4aN2b) Body None 4 No Left scapular tip No 85/F SCC Anterior mandible (T4aN0) Anterior mandible None 5 No Right scapular tip and scapular fasciocutaneous 75/M SCC Anterior mandible (T4aN0) Anterior mandible None 7 Yes - single Right scapular tip and latissimus dorsi No 71/F SCC Anterior mandible (T2N0) Anterior mandible None 7.5 No Right scapular tip and latissimus dorsi No 63/M SCC Anterolateral mandible (T4aN0) Anterolateral mandible Surgery / RT 5 No Right scapular tip and latissimus dorsi No 56/M SCC Retromolar trigone (T4aN0) Body and angle CRT 7 No Right scapular tip and latissimus dorsi No 56/M SCC Retromolar trigone (T4aN0) Ramus / angle None 7 No Left scapular tip and latissimus dorsi No 59/M SCC Retromolar trigone (T4aN0) Angle None 7.5 No Left scapular tip No 81/M SCC Angle of mandible (T4aN1) Angle Surgery / RT 7 No Right scapular tip and latissimus dorsi No 86/M SCC Angle of mandible (T4aN1) Body and angle None 8 No Right scapular tip Yes Postoperative neck hematoma 80/M SCC Angle of mandible (T4aN1) Angle None 7 No Right scapular tip No 58/M SCC Angle of mandible (T4aN0) Body and angle None 8 No Right scapular tip Yes Flap failure revised with pedicled pec major 68/M SCC Angle of mandible (T4aN0) Angle Surgery / CRT 5 No Left scapular tip and latissimus dorsi No 74/F SCC Mandibular alveolus (T3N0) Body None 4 No Left scapular tip No No Abbreviations: CRT, chemoradiotherapy; SCC, squamous cell carcinoma; RT, radiotherapy.

4 MANDIBLE RECONSTRUCTION WITH SCAPULAR TIP an osteotomy for flap inset. This case involved a patient with multiple comorbidities including severe peripheral vascular disease who had undergone chemoradiotherapy and 3 prior oromandibular resections, including a fibular free flap, over the previous 5 years. Six cases were revision surgeries as defined by previous oromandibular resections and/or neck dissections. Three cases required anastomosis to the contralateral neck vessels. Pedicle length was sufficient to obviate vein grafts in all cases. Three patients required return visits to the operating theater with 1 developing a neck hematoma, another a donor site hematoma, and a third for surgery-related flap failure. This patient was morbidly obese (body mass index of 48), preoperatively bedridden, with significant coexisting medical conditions including extensive vascular disease. Postoperatively, the patient developed renal failure and hemodynamic instability. The free flap was noted to be compromised, but due to patient instability, no attempt was made to salvage the flap. A secondary reconstruction for soft tissue coverage was carried out with a pedicled pectoralis major myogenous flap. DISCUSSION The scapula as a donor site for osseous free tissue transfer was originally described by Teot et al 12 in 1981, and has now been used for over 30 years. Deraemaecker et al 13 initially described the use of the scapular tip isolated on the angular artery in In 1991 Coleman and Sultan 7 reported on 14 cadaveric and 22 operative dissections of the angular artery, with 8 patients in the reported series undergoing reconstruction of various complex head and neck defects with this versatile free flap. Their landmark article provided a clear insight into the benefits of the improved pedicle length with this flap in addition to the well-established advantages of using the scapular system as a donor site including versatile soft tissue paddles and low donor site morbidity. Further studies describing the anatomic features and surgical anatomy of the STFF have been published over the years Seitz et al 10 reported on 125 cadaveric dissections in 1999 that demonstrated the vascular patterns of the subscapular system. In 81 of the dissections, the average length of the angular artery was 68.3 mm. Five different branching patterns of the angular branch were described, although the vast majority arose from either the thoracodorsal or serratus anterior arteries. Similar results were seen by Seneviratne et al 9 in 81 cadaveric dissections of the thoracodorsal system. In addition, their ink injection studies confirmed reliable perfusion of the scapular tip and lateral border of the scapula when supplied by the angular artery. Specific advantages of the scapular tip as a donor flap have been neatly summarized by Chepeha et al. 2 These include: (1) a long pedicle, (2) independently mobile tissue components, and (3) a variety of 3-dimensional shapes able to be harvested. Furthermore, the reduced amount of atherosclerotic disease affecting the subscapular vascular system, as compared to lower limb and iliac crest systems, may be important especially in the elderly patients with cancer. 2,14 Harvesting from the scapular system offers several benefits in postoperative patient care. Early ambulation is possible in this patient group compared with fibula and iliac crest donor sites. This facilitates physiotherapy measures, improves pulmonary function, and reduces the general risks related to prolonged immobility. The avoidance of significant abdominal pain associated with the iliac crest flap may further improve rehabilitation during this early postoperative period. The unique shape of the scapular tip offers advantages in certain clinical situations. The scapular tip is ideal for the mandibular angle defect (Figure 2). The natural angular shape of the tip can be positioned to match various defects of the body and angle of the mandible while eliminating the need for osteotomies (as demonstrated in 2 different patients CT scans in Figure 3 and Figure 4). The medial and lateral scapular border extensions can be harvested to fit the defect created by the ramus and body. Most of the defects in our series were situated around the angle of the mandible, with 1 case requiring resection of the condyle. No osteotomies were required for mandibular angle reconstruction in this series. There are limited elegant options among conventional bone flaps when a short segment of bone is required. The use of the fibula in this setting wastes considerable proximal bone with the incurred morbidity. Harvesting a short segment iliac crest or the lateral scapula (based on the circumflex scapular artery) still requires significant muscular dissection while retaining its short vascular pedicle. No less morbidity is incurred than when longer bone segments are taken. In comparison, the STFF is an excellent choice for linear short segments such as isolated defects of the mandibular body or ramus. Harvesting scapular tip bone segments as small as 4 cm are easily customizable and associated with extremely little donor site morbidity. There may also be a unique role for the scapular tip for condylar/ramus reconstruction, as was required in 1 patient in our series (Figure 5). In this case, the flap was oriented such that the fibrous tip was used to reconstruct the condylar head with excellent mouth opening postoperatively and relief of disease-related trismus (Figure 6). In our series, the length of the osseous flap averaged 6.2 cm with the longest segment measuring 8 cm. This compares similarly to the average length of 5.2 cm (2.5 cm 9 cm) described by Chepeha et al 2 in their series of 21 cases of head and neck reconstruction. For bone requirements longer than 8 cm and where the fibula is contraindicated, our preferred option is to extend our scapular bone harvest onto the lateral scapular border or to harvest a standard lateral scapular flap. When possible, we preserve the circumflex scapular vessels and its osseous branches. The STFF is an excellent option in the setting of revision surgery when the lower or contralateral neck may be the source of the recipient vessel. Due to pedicle lengths of up to 17 cm, vein grafts may be avoided by selecting this bone flap In our series, one third of our patients had prior surgery, radiotherapy 6 chemotherapy or a combination. In all cases, the pedicle length was satisfactory without requiring vein grafting. 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5 YOO ET AL. FIGURE 3. Three-dimensional CT viewed inferiorly demonstrating reconstruction of the natural contour of the left mandibular body with scapular tip free flap (STFF). [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.] within the neomandible due to the thin plate of scapular bone. 15,16 In addition, the shallow mandibular profile is esthetically suboptimal. Our preference is to orientate the scapular bone in a vertical position. The corticocancellous bone of the lateral scapular border can support dental implants, although it is generally considered inferior to the iliac crest for this indication. 17,18 The capacity to harvest single or multiple independent soft tissue paddles as a chimeric flap affords great flexibility in reconstruction of complex defects and may avoid FIGURE 2. (A) Right mandibular angle defect. (B) Scapular tip free flap (STFF) reconstruction of right mandibular angle defect. (C) Postoperative result after mandibular angle reconstruction with STFF. For defects of the symphysis, some authors have described the scapular tip oriented horizontally without osteotomies to recreate the contour of the anterior mandible line. This generally precludes dental implantation FIGURE 4. Three-dimension CT demonstrating reconstruction of mandibular angle with scapular tip free flap (STFF). [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.] 984 HEAD & NECK DOI /HED JULY 2013

6 MANDIBLE RECONSTRUCTION WITH SCAPULAR TIP FIGURE 5. (A) Defect of right mandibular ramus including condyle, with harvested scapular tip free flap (STFF). (B) STFF inset with fibrous tip positioned to reconstruct the mandibular condyle. (C) Three-dimensional CT demonstrating STFF reconstruction of the right ramus and condyle following surgical resection of recurrent osteosarcoma. A portion of the original fibula free flap reconstruction of the right mandibular body remains in situ. Note the accurate restoration of dental occlusion. (D) Three-dimensional CT viewed inferiorly following STFF reconstruction of right ramus and condyle. multiple free flaps. 7,16,18 Although abundant skin is available, our preferred approach was to use the myogenous extensions such as the teres major, serratus anterior, or latissimus dorsi without skin for intraoral lining. The exposed muscle is left to remucosalize and has been demonstrated to provide a reliable reconstruction. 13 Similar techniques have been described using internal oblique based on the iliac crest flap with excellent functional outcomes. 19,20 The STFF does have certain limitations and disadvantages. The limited length of available bone is a relative disadvantage that may preclude its use for extended mandibular defects. For defects which are greater than 10 cm, involve the central mandibular segment, or require multiple osteotomies, our preferred option remains the fibula free flap. In these selected defects where the fibula is not an option and/or where the soft tissue requirements are complex, such as through-and-through defects, the lateral scapula border free flap is often used. Our experience with the fibula and subscapular system of bone flaps has eliminated the iliac crest and radius in almost all circumstances. Other disadvantages of the STFF include the inability to use a concurrent 2-team approach and the complex 3- dimensional anatomy of the subscapular system. The perceived inconvenience of patient repositioning in the midst HEAD & NECK DOI /HED JULY

7 YOO ET AL. FIGURE 6. Post-operative result of Figure 5 patient: right mandibular ramus/condyle reconstruction using scapular tip with correction of severe trismus. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.] of surgery has largely been overcome with initial patient positioning at 20 to 30 degrees lateral decubitus. This allows both the ablative and reconstructive teams adequate exposure to operate unimpeded. CONCLUSIONS At our institution, the STFF is the first-line option for mandibular reconstructions of: (1) defects involving the mandibular angle, (2) short-segment linear defects of the ramus or body, (3) revision surgery in order to avoid vein grafts, (4) concurrent complex soft tissue requirements, and (5) elderly patients or patients with significant comorbidities. REFERENCES 1. Bak M, Jacobson AS, Buchbinder D, Urken ML. Contemporary reconstruction of the mandible. Oral Oncol 2010;46: Chepeha DB, Khariwala SS, Chanowski EJ, et al. Thoracodorsal artery scapular tip autogenous transplant: vascularized bone with a long pedicle and flexible soft tissue. Arch Otolaryngol Head Neck Surg 2010;136: Moukarbel RV, White JB, Fung K, Franklin JH, Yoo JH. The scapular free flap: when versatility is needed in head and neck reconstruction. J Otolaryngol Head Neck Surg 2010;39: Clark JR, Vesely M, Gilbert R. Scapular angle osteomyogenous flap in postmaxillectomy reconstruction: defect, reconstruction, shoulder function, and harvest technique. Head Neck 2008;30: Ilankovan V, Ramchandani P, Walji S, Anand R. Reconstruction of maxillary defects with serratus anterior muscle and angle of the scapula. Br J Oral Maxillofac Surg 2011;49: Uğurlu K, Sacak B, Hüthüt I, Karsidag S, Sakiz D, Bas L. Reconstructing wide palatomaxillary defects using free flaps combining bare serratus anterior muscle fascia and scapular bone. J Oral Maxillofac Surg 2007;65: Coleman JJ III, Sultan MR. The bipedicled osteocutaneous scapula flap: a new subscapular system free flap. Plast Reconstr Surg 1991;87: dos Santos L. The vascular anatomy and dissection of the free scapular flap. Plast Reconstr Surg 1984;73: Seneviratne S, Duong C, Taylor GI. The angular branch of the thoracodorsal artery and its blood supply to the inferior angle of the scapula: an anatomical study. Plast Reconstr Surg 1999;104: Seitz A, Papp S, Papp C, Maurer H. The anatomy of the angular branch of the thoracodorsal artery. Cells Tissues Organs 1999;164: Brown J, Bekiroglu F, Shaw R. Indications for the scapular flap in reconstructions of the head and neck. Br J Oral Maxillofac Surg 2010;48: Teot L, Bosse JP, Moufarrege R, Papillon J, Beauregard G. The scapular crest pedicled bone graft. Int J Microsurg 1981;3: Deraemaecker R, Thienen CV, LeJour M, Dor P. The serratus anterior free flaps. In: Proceedings of the Second International Conference on Head and Neck Cancer. July 31, 1988; Boston, Mass. 14. Bartlett SP, May JW Jr, Yaremchuk MJ. The latissimus dorsi muscle: a fresh cadaver study of the primary neurovascular pedicle. Plast Reconstr Surg 1981;67: Hanasono MM, Skoracki RJ. The scapular tip osseous free flap as an alternative for anterior mandibular reconstruction. Plast Reconstr Surg 2010; 125:164e 166e. 16. Yamamoto Y, Nohira K, Yamashita T, et al. Combined V figure-shaped scapular osteocutaneous and latissimus dorsi myocutaneous flap for composite mandibular reconstruction. Head Neck 1995;17: Schultes G, Gaggl A, K archer H. Stability of dental implants in microvascular osseous transplants. Plast Reconstr Surg 2002;109: ; discussion Beckers A, Schenck C, Klesper B, Koebke J. Comparative densitometric study of iliac crest and scapula bone in relation to osseous integrated dental implants in microvascular mandibular reconstruction. J Craniomaxillofac Surg 1998;26: Brown JS. Deep circumflex iliac artery free flap with internal oblique muscle as a new method of immediate reconstruction of maxillectomy defect. Head Neck 1996;18: Genden EM, Wallace D, Buchbinder D, Okay D, Urken ML. Iliac crest internal oblique osteomusculocutaneous free flap reconstruction of the postablative palatomaxillary defect. Arch Otolaryngol Head Neck Surg 2001; 127: HEAD & NECK DOI /HED JULY 2013