Iliac Crest Internal Oblique Osteomusculocutaneous Free Flap Reconstruction of the Postablative Palatomaxillary Defect

Background  Traditionally, restoration of extensive palatomaxillary defects have been achieved by prosthetic restoration, often with suboptimal functional results. More recently, vascularized bone-containing free flaps have been used for this purpose.

Objective  To describe 6 patients who underwent palatomaxillary reconstruction using the composite iliac crest–internal oblique osteomusculocutaneous free flap.

Methods  Six cases of iliac crest osteomusculocutaneous free flap reconstruction of extensive postablative palatomaxillary defects were retrospectively reviewed with clinical follow-up. We reviewed these cases for pathologic findings, defect size, dental restoration, oral rehabilitation, and speech.

Results  Pathologic findings included squamous cell carcinoma (n = 4), osteogenic sarcoma (n = 1), and sinonasal hemangiopericytoma (n = 1). Mean follow-up was 14.5 months (range, 10-25 months). Four patients underwent resection and reconstruction primarily and 2 underwent reconstruction secondarily. Two patients required reconstruction of a cutaneous defect using the iliac skin paddle. The hard palate and lateral nasal wall were reconstructed in all 6 patients, and the orbital rim and zygomatic body were reconstructed in 4. One patient underwent reconstruction with an orbital prosthesis supported by osseointegrated implants. There was 1 donor site complication and 1 recipient site infection, which was treated successfully with oral antibiotics. Four patients were rehabilitated with osseointegrated implants, and all 6 patients maintain an unrestricted oral diet. All 6 patients have normal speech without velopharyngeal or oronasal insufficiency.

Conclusion  For extensive palatomaxillary defects, the iliac crest–internal oblique osteomusculocutaneous free flap offers a reliable method of primary reconstruction, allowing for complete orodental rehabilitation without the use of a prosthetic obturator.

THE 3-DIMENSIONAL architecture of the maxillary skeleton serves functional and aesthetic roles. Functionally, the palate provides an occlusal surface for the mandible during mastication and supports the globe, the nasal airway, and the pharyngeal musculature essential to initiation of deglutition. Aesthetically, the maxilla serves as a scaffold that is responsible for projection of the nose, the cheek, and the anterior midface. As a result of this complex interaction between form and function, defects in the palatomaxillary complex can lead to devastating functional as well as cosmetic consequences. Prosthetic obturation, local soft tissue flaps, free bone grafts, pedicled soft tissue flaps, and, more recently, vascularized bone-containing free flaps (VBCFFs) have all played a role in the evolution of palatomaxillary restoration.

In the past, tissue-borne prosthetic obturation was the only option for orodental rehabilitation of postablative palatomaxillary defects. Although prosthetic obturation has several advantages, including immediate dental restoration without the need for further surgery, it is also associated with a variety of shortcomings, most notably, instability and poor retention. A breakdown in the oronasal prosthetic-tissue seal, characteristic of prosthetic instability, might lead to oronasal insufficiency manifest as oronasal regurgitation and compromised speech. These shortcomings are accentuated in edentulous patients, irradiated patients, and those who have undergone extensive resections. In an effort to achieve improved prosthetic stabilization and retention, the surgeon and the prosthodontist have been encouraged to work together to develop surgical and nonsurgical measures for achieving functional success.

Conventional surgical considerations for prosthetic rehabilitation have focused on placement of a split-thickness skin graft within a palatomaxillary defect and on formation of tissue undercuts to aid in the creation of fibrous scar bands. When it is possible, surgical cuts should be made adjacent to canine or molar teeth. Characteristically, these teeth have superior root form and can be clasped by the obturator framework to enhance prosthetic stability.

Nonsurgical considerations have focused on enhancing the favorable biomechanical forces and deemphasizing the counterproductive lever forces placed on the obturator. Several publications^1-5 have been devoted to techniques aimed at minimizing the destabilizing forces. However, as the amount of residual palate diminishes, and the palatal defect enlarges, the cantilever forces² become overwhelming, leading to prosthetic instability and a poor functional result.

Large defects adversely affect prosthetic retention in 2 ways. In such defects, less dentition is available to clasp, and the diminished retentive surface area results in greater cantilever forces over the defect. As a result, the prosthesis tends to tip toward the defect. In smaller defects, the fulcrum is positioned across 2 stable teeth, usually the canine and the third molar. Each has characteristically strong root form and will support clasping. In addition, the dentition oriented perpendicular to the fulcrum line can be securely clasped. However, techniques to neutralize these counterproductive forces become obsolete in extensive palatal defects because the retentive mechanisms, such as dentition, palatal surface area, and bony undercuts, are diminished. To stabilize prosthetic restoration of large palatal defects, the surgeon must supplement bone to increase the area of the palatal arch. This can be achieved by the addition of vascularized or nonvascularized bone into which osseointegrated implants can be placed and a stable fulcrum line reestablished.

In an effort to achieve successful implant stability through osseointegration, a variety of techniques have been used to restore bone to the maxilla. Free iliac bone,⁶ vascularized rib with latissimus dorsi and periosteal flaps,⁷ and vascularized cranial bone flaps⁶ were used in the 1980s. Although these methods provided bone to the region, they were often insufficient for implant placement, and the soft tissue was commonly too bulky to permit retention of tissue-borne dentures.

Application of microvascular reconstruction to the head and neck has greatly impacted the surgeon's approach to defect restoration and functional rehabilitation. Superior functional results in mandibular reconstruction using VBCFFs^8,9 led to application of the osteocutaneous scapular free flap,¹⁰ followed by a variety of publications describing fibular-containing^11,12 and iliac bone–containing^13,14 free flaps for maxillary reconstruction. Vascularized bone-containing free flaps offer several benefits for primary maxillary reconstruction over traditional palatomaxillary obturation. This technique permits the single-staged transfer of vascularized soft tissue and bone, which is capable of separating the oral and nasal cavities as well as providing bone adequate for the placement of osseointegrated implants. This technique eliminates the limitations of vascular pedicle length associated with regional flap reconstructions. The mobility of the skin paddle relative to the bone flap permits the restoration of complex 3-dimensional defects of the palatomaxillary complex that otherwise require prosthetic restoration. Probably, the most significant advantage of free tissue reconstruction is the ability to rehabilitate extensive palatomaxillary defects. The biomechanical forces placed on a palatomaxillary obturator, particularly in extensive defects in which the retentive surface is diminished, leads to a cascade of destabilizing forces. Reconstruction with autologous bone and soft tissue restores a permanent soft tissue seal, preserving oronasal competence, restoring nasal lining, and providing a fixed segment of bone ideal for dental rehabilitation.

We retrospectively reviewed 6 cases of palatomaxillary reconstruction using the iliac crest VBCFF combined with the internal oblique muscle. In this series, we evaluated our ability to achieve a separation between the oral and nasal cavities, dental rehabilitation, intelligible speech, a patent nasal airway, and satisfactory cosmetic restoration.

The study population consists of 6 consecutive patients who presented to The Mount Sinai Medical Center, a tertiary referral center for otolaryngology in New York, NY, with either a malignancy of the palatomaxillary complex or a palatomaxillary defect as a result of a previous ablative surgery. All 6 patients were offered the option of surgical or prosthetic reconstruction, and all were explained the risks and benefits of each method of orodental rehabilitation.

Each case was retrospectively reviewed for the patient's ability to maintain intelligible speech, orodental rehabilitation, a patent nasal airway, and a satisfactory cosmetic result. Oronasal separation and a patent nasal airway were assessed by direct examination. Intelligible speech and oral rehabilitation were assessed by a licensed speech pathologist.

After the maxillary resection, an iliac crest–internal oblique VBCFF was harvested in the manner previously described by Urken et al.⁹ In all cases, the internal oblique muscle, based on the ascending branch of the deep circumflex iliac artery and vein, was harvested with the vascularized bone graft. Skin paddle overlying the iliac crest was harvested in cases in which a cutaneous defect existed. After the free flap was removed from the donor site, the iliac bone flap was contoured using a reciprocating saw, which allowed for the fashioning of a piriform aperture and orbital rim. Additional bone was used for restoration of the prominence of the zygomatic body, which was performed by placing a free on-lay bone graft onto the vascularized iliac bone. The bone graft was fixed with 2 titanium lag screws. The internal oblique muscle was sutured to the cut edge of the remaining palatal mucosa and then used to resurface the lateral nasal wall (Figure 1). The distal edge of the internal oblique was sutured to the superior aspect of the remaining nasal and ethmoid bones by making drill holes in the bone. The internal oblique served to resurface the palate and the lateral nasal wall, and in the case of a previous orbital exenteration, the orbital cavity. Once the bone was properly fashioned and the internal oblique was sutured to reline the neopalate and the lateral nasal wall, the iliac bone graft was fixed to the remaining maxilla, zygoma, and nasal bones using titanium miniplates. The vascular pedicle was delivered through a subcutaneous tunnel made along the cheek. In all cases, the facial artery and vein were used without a vein graft as recipient vessels.

Six consecutive patients underwent palatomaxillary reconstruction using the iliac crest–internal oblique VBCFF. Patients were followed up after surgery for an average of 14.5 months (range, 10-25 months). The patient population consisted of 5 men and 1 woman, ranging in age from 42 to 63 years (mean, 52 years). Four patients had squamous cell carcinoma of the maxillary sinus, 1 had an osteogenic sarcoma of the maxillary sinus, and 1 had a hemangiopericytoma of the lateral nasal wall that had invaded the adjacent sinus (Table 1). Five patients underwent surgical therapy and primary reconstruction at The Mount Sinai Medical Center. One patient underwent primary surgical therapy and postoperative external beam radiation at another institution and subsequently presented to The Mount Sinai Medical Center for secondary reconstruction.

Five of 6 defects involved at least half of the hard palate, the orbital rim, and the body of the zygoma (Table 1). One patient underwent an infrastructure maxillectomy involving half of the palate without ablation of the orbital rim or zygoma. Patient 4 presented for a secondary reconstruction after a previous resection involving the hard palate, the orbital rim, and the body of the zygoma as well as an orbital exenteration and resection of the skin of the cheek (case presentation 2). This patient had undergone concomitant radiation therapy and chemotherapy. At the time of presentation, the patient had also developed osteoradionecrosis of the medial margin of the hard palate. The cutaneous defect was reconstructed using a combination of the iliac skin paddle and a split-thickness skin graft placed over the distal tip of the internal oblique muscle. A second patient sustained a cutaneous defect of the lateral cheek that was reconstructed using only the iliac skin paddle.

All 6 patients underwent successful reconstruction with an iliac crest VBCFF. There were no intraoperative complications. After surgery, patient 2, who had sustained a cutaneous defect of the lateral cheek, required leech therapy early in the postoperative course for the successful treatment of transient venous congestion that involved only the cutaneous portion of the composite flap. One patient sustained a postoperative donor site abdominal hernia that was repaired successfully secondarily. Two patients underwent placement of Marlex mesh in the primary closure of the iliac crest donor site, and all 6 patients were ambulatory by postoperative day 5.

Four patients underwent primary placement of osseointegrated dental implants (Table 1). One patient underwent secondary placement of osseointegrated implants, and 1 did not undergo implant placement. Five of 6 patients rehabilitated with implant-borne dentures are currently eating an unrestricted oral diet. One patient did not undergo implant placement because of financial limitations; however, this patient currently manages a soft diet. Patient 4 underwent placement of osseointegrated implants in the native superior orbital rim and iliac bone graft for retention of an orbital prosthesis.

All 6 patients have successful permanent separation of the oral and nasal cavities and excellent speech quality, with no evidence of oronasal escape or velopharyngeal insufficiency. Five of 6 patients are currently free of disease. Patient 2 is presently being treated for locally recurrent disease.

The patient is a 59-year-old man with no significant past medical history who presented with complaints of right maxillary sinus pressure and epiphora. Computed tomography demonstrated a right maxillary sinus mass with invasion into the right lateral nasal wall.

A right hemimaxillectomy and resection of the inferior orbital rim and body of the zygoma was performed after a transnasal biopsy, which was interpreted as fibrosarcoma (Figure 1). An iliac crest–internal oblique osteomusculocutaneous free flap was harvested without a skin paddle. The iliac crest was fashioned to recreate the nasal piriform aperture and the inferior orbital rim (Figure 2 and Figure 3). The vascularized iliac bone flap was fixed to the adjacent maxilla, the remaining lateral nasal bones, and the remnant of the zygoma using titanium miniplates. The internal oblique muscle was used to reline the palate and resurface the ipsilateral lateral nasal wall. Free bone grafts were lag screwed to the anterior surface of the iliac bone to restore the prominence of the body of the zygoma (Figure 4). The iliac bone was oriented with the crest along the inferior border to restore the new maxillary alveolus. Osseointegrated dental implants were primarily placed into the neoridge of the iliac bone. A subcutaneous tunnel was made along the cheek, and a separate incision was made inferior to the ipsilateral mandibular ramus. The facial artery and vein were isolated as recipient vessels for the microvascular anastomoses, which were performed without vein grafts.

Subsequently, the neopalate mucosalized and the patient underwent the fabrication and placement of an implant-borne denture (Figure 5). He currently tolerates an unrestricted oral diet. He has achieved an acceptable cosmetic result with near normal midface contour (Figure 6).

This patient is a 53-year-old man with a history of squamous cell carcinoma of the right maxillary sinus. The patient underwent a right radical maxillectomy with orbital exenteration and postoperative external beam radiation at another hospital. Several failed attempts had been made to fabricate a prosthesis for a combined orbital-palatal-cutaneous defect. The patient presented with a cutaneous lateral cheek defect, chronic purulent drainage from the orbital exenteration site, and osteoradionecrosis of the remaining palatal margin (Figure 7).

Nonvital bone was excised from the residual palate and orbit, and an iliac crest–internal oblique osteomusculocutaneous free flap was harvested from the ipsilateral hip. The iliac bone was fashioned to reconstruct the palatal alveolus, the inferior orbital rim, and the nasal piriform aperture (Figure 8). Miniplates were used to secure the iliac bone to the remaining palate. The internal oblique muscle was used to reline the palate, the lateral nasal wall, and the orbital exenteration site. A split-thickness skin graft was sutured to the underlying muscle in the orbit, and the iliac skin paddle was used to restore the lateral cheek defect.

Osseointegrated dental implants were primarily placed into the neoalveolus and along the native superior orbital rim and the newly created inferior orbital rim for future placement of an orbital prosthesis. This patient's postoperative course was complicated by a minor wound infection, which was successfully treated with oral antibiotics. Three months after surgery the implants were uncovered and the patient was orally rehabilitated with an implant-borne dental prosthesis and an orbital prosthesis (Figure 9). A 3-dimensional computed tomographic scan demonstrates the position of the iliac crest relative to the native maxilla (Figure 10). Currently, the patient tolerates an unrestricted regular diet.

Although prosthetic obturation or adjacent tissue transfer offers equivalent functional results for smaller defects, debate still exists with regard to the optimal method of reconstruction of more extensive defects.^15,16 Some researchers have advocated the prosthetic restoration of all hemipalatectomy defects,^2,5 whereas others believe that such defects, in which the unfavorable biomechanical forces lead to an unstable or nonretentive prosthesis, are overwhelming and are best rehabilitated using a VBCFF.^16,17

In the typical hemipalatectomy defect, the anterior abutment tooth is either the central or lateral incisor. Retention is not uncommonly provided by framework designs, where clasps to the incisor are provided in an effort to distribute the load. Such clasps often splint 2 or more adjacent teeth. However, despite these load-sharing designs, the inadequate root form of the incisors make stabilization of the prosthesis difficult. Furthermore, the hemipalatectomy defect shifts the fulcrum line to an unfavorable position, leading to increased tipping forces. As a result, obturated patients often have difficulty with mastication. The unfavorable forces are a particular problem in the edentulous patient or in previously irradiated patients whose teeth are absent or poorly suited to withstand the stresses of a clasp.

Soft tissue flaps are effective for relining the oral cavity and separating the oral and nasal cavities. However, placement of a soft tissue flap obliterates the maxillectomy cavity and eliminates the retentive properties of the mucocutaneous scar band and the medial palatal shelf, thereby adversely affecting the prognosis for a stable tissue-borne dental prosthesis. Furthermore, the absence of bone will prevent the placement of osseointegrated implants. As a result, patients are left without the opportunity for dental rehabilitation. Several attempts to combine a fasciocutaneous flap^18-20 or a temporalis flap^21,22 with free bone grafts have been used to address this problem. Choung et al¹⁹ advocated using a parietal osteofascial flap with vascularized cranial bone grafts for maxillary reconstruction, and, more recently, Cordeiro et al¹⁸ reported the wrapping of nonvascularized bone grafts in a radial forearm free flap. Although cranial bone grafts can be stacked and wrapped in vascularized tissue to increase the bone stock and therefore accommodate osseointegrated implants, success with this technique is limited because of poor bone graft vascularization and resultant bone resorption. Furthermore, reconstruction of extensive defects is limited by the amount of available donor bone.

The goal of palatomaxillary reconstruction is to achieve a level of function and cosmesis similar to the predisease state. To achieve this goal, 2 broad aims must be accomplished: first, to shift the fulcrum line away from the midline, thereby decreasing the tipping forces and improving the equal distribution of masticatory forces, and, second, to address the vertical component of the defect, namely, the orbital rim/floor and the body of the zygoma. Defects of the zygomatic body are extremely difficult to rehabilitate using a prosthesis. Reconstruction of the hemipalatectomy defect using VBCFF offers several unique advantages to orodental rehabilitation that cannot be realized with other forms of prosthetic or soft tissue reconstruction. Most important, free tissue transfer allows for the bony restoration of the absent maxillary alveolus. Placement of osseointegrated implants, and subsequent fitting of an implant-borne denture, offers patients an excellent orodental rehabilitation without the inconvenience or instability associated with prosthetic devices. Although the pure hemipalatectomy defect (an infrastructure maxillectomy) can be adequately managed with either prosthetic rehabilitation or bone-containing free flaps, the unique advantage of a VBCFF is realized in defects that involve the vertical component of the palatomaxillary complex, specifically, the orbital rim, the body of the zygoma, and cutaneous defects.

Palatomaxillary defects involving the orbital rim and/or the zygomatic body are particularly difficult to reconstruct prosthetically. Resection of the orbital floor, the orbital rim, and/or the globe itself represents a functional and aesthetic problem. The bony architecture of the orbit acts to support the globe and provide midface form. Vertical orientation of the iliac bone–containing free flap provides a bony rim that might serve as a shelf to secure an orbital floor reconstruction, or in the case of an orbital exenteration, provide bone for the placement of implants for a future prosthetic globe.

Extensive resections might involve the lateral orbital rim, the zygoma, and, in some cases, the skin of the lateral cheek. Reconstruction of the zygoma will often require the placement of free bone grafts, which can be secured using lag screws placed directly into the iliac bone.

The scapula, fibula, and iliac crest bone–containing free flaps have all been described for palatomaxillary reconstruction^12-14; however, we believe that each donor site has a well-defined role that is largely determined by the nature of the defect. Each donor site offers a unique source of bone and associated soft tissue and muscle. As a result, choosing the most appropriate donor site requires a preoperative assessment of the anticipated defect.

During the past 2 decades, the iliac crest became a popular donor site for the reconstruction of complex composite oromandibular defects. The addition of the internal oblique muscle based on the ascending branch of the deep circumflex iliac artery and vein provides a unique tripartite design consisting of vascularized bone and skin based on a single vascular pedicle. Initially described by Ramasastry et al²³ for extremity reconstruction, the iliac crest–internal oblique VBCFF was subsequently modified by Urken et al^9,24,25 and used extensively in oromandibular reconstruction. Subsequently, Brown¹⁴ described using the iliac crest–internal oblique composite flap as a method of palatomaxillary reconstruction. Brown reported 3 cases using the iliac crest–internal oblique muscle VBCFF to immediately reconstruct a low central defect, a moderate lateral defect, and a high complex defect with an orbital exenteration. Brown oriented the iliac bone horizontally in 2 defects and vertically in 1. One of the 3 patients was successfully rehabilitated with osseointegrated dental implants, and 1 patient who had undergone an orbital exenteration was scheduled for the future placement of osseointegrated implants for an orbital prosthesis. None of the patients in the series by Brown required reconstruction of a cutaneous defect.

In this series, we found that the iliac crest free flap offers an ideal source of tissue for the reconstruction of subtotal defects of the palatomaxillary complex. In particular, defects that involve a vertical component of the maxilla can be appropriately managed by orienting the bone flap vertically. This allows the internal oblique muscle to serve as a neopalate and lateral nasal wall. The tremendous flexibility of the internal oblique muscle based on its axial blood supply in 80% of cases provides the necessary mobility of the soft tissue flap relative to the bone, which is critical for restoring the complex 3-dimensional anatomy of the midface region. Similarly, the vertically oriented bone graft can be fashioned to duplicate the piriform aperture and the orbital rim. Palatomaxillary reconstruction of complex defects can be achieved with the fibular²⁶ and the scapular¹⁰ donor sites; however, the ability to contour the hearty bone stock associated with the iliac crest uniquely allows for the restoration of the horizontal and vertical components of these defects. Although the scapular donor site has been used in adult¹⁰ and pediatric²⁷ populations for maxillary rehabilitation, the ability to reconstruct the 3-dimensional buttress system of the maxilla is limited.

All 6 patients included in this review had a patent nasal airway. The internal oblique muscle was used to reline the nasal airway, and, after several weeks, the denervated muscle atrophied and mucosalized. Two patients sustained mild epiphora as a result of lacrimal duct stenosis despite placement of a lacrimal stent at the time of surgery. Secondary procedures were necessary to correct this condition. The neopalate resulted from mucosal ingrowth over the atrophied, denervated internal oblique muscle, resulting in an arched hemipalate that simulated the appearance of the intact native palate. None of the patients had oronasal escape or velopharyngeal insufficiency. As a result, all 6 patients had normal speech and articulation.

Vertical orientation of the iliac bone graft serves to reconstruct the orbital rim, which is often difficult to accomplish with scapula or fibula VBCFFs. Titanium mesh or free cortical bone grafts can be fixed to the neo-orbital rim to provide support for the globe. Four of 6 patients reviewed in this series have normal globe position relative to the contralateral eye. One patient had a previous orbital exenteration, and another patient did not require resection of the orbital floor. All 6 patients achieved facial symmetry after reconstruction of the zygoma with free bone grafts; however, 1 patient required secondary revision surgery. Similarly, 2 patients required a revision dacrocystorhinostomy for epiphora.

Five patients underwent placement of osseointegrated implants, followed by implant-borne dental rehabilitation. Patients rehabilitated with implant-borne dentures are maintaining an unrestricted diet and deny any problem with mastication of solid food. The single patient who was not rehabilitated with implant-borne dentures is maintaining a soft diet without difficulty. We found that patients who undergo maxillary reconstruction and orodental rehabilitation have a significantly improved functional prognosis relative to patients who undergo mandibular reconstruction and orodental rehabilitation. This is likely because the tongue is unaffected in palatomaxillary carcinoma. Therefore, the onus of restoring the oral phase of deglutition and mastication is more easily achieved using palatomaxillary resection or reconstruction.

Although this review demonstrates the high level of orodental rehabilitation that can be achieved with iliac crest VBCFF reconstruction of the extensive palatomaxillary defect, a prospective evaluation comparing prosthetic and VBCFF reconstruction is necessary to elucidate the impact of this technique on function, form, and quality of life. We are currently conducting a 2-arm outcomes study in an effort to examine these factors.

The goals of palatomaxillary reconstruction are to support the orbital contents, separate the oral cavity and nasal cavity, reconstruct the palatal surface, reconstruct the lacrimal apparatus, provide facial symmetry, and achieve dental rehabilitation. The iliac crest–internal oblique VBCFF offers an excellent source of tissue to achieve these goals. It has become evident through the course of this review that patients with extensive defects of the palatomaxillary complex profoundly benefit from iliac crest VBCFF reconstruction. The addition of vascularized bone to the midface allows for the equal distribution of forces associated with chewing. The bone stock provides an excellent scaffold for the placement of osseointegrated implants for the retention of dental and orbital prostheses. Furthermore, cutaneous defects of the lateral cheek, which are poorly managed by prosthetic reconstruction, are effectively treated using the iliac skin paddle.

Accepted for publication January 18, 2001.

Presented at the annual meeting of the American Head and Neck Society, Fifth International Conference on Head and Neck Cancer, San Francisco, Calif, August 1, 2000.

Corresponding author: Eric M. Genden, MD, Department of Otolaryngology–Head and Neck Surgery, Box 1189, The Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029.