3 Ablative and reconstructive surgery of the midface and craniofacial junction
3.1 Approaches and access osteotomies to the midface
Disorders involving the midface are numerous including congenital abnormalities, acquired posttraumatic deformities, benign and malignant neoplastic lesions, as well as degenerative and inflammatory processes.
The midface is a fundamental anatomical structure paramount for both the cosmetic and functional properties of the face including orbital support, mastication, airway, and facial appearance. Treatment of the disorders of the midface are complicated because of important structures, such as the orbits and the anterior portion of the skull base, and the need to preserve or reconstruct functional entities like the upper dental arch, airway, and maxillary and ethmoid sinuses. This complexity paired with the diversity of pathologies has historically garnered significant attention from surgeons to both refine existing and develop novel therapeutic approaches. Complete removal of disease remains the most basic mandate of oncological principles, which necessitates the experienced surgeon to master a variety of techniques, both open and endoscopic, in managing disorders involving the midface. From these efforts, a plethora of surgical techniques have been developed to gain access to the different areas of the midface. The goal of these approaches is to provide adequate exposure without compromise to treatment of the disorder with little cosmetic or functional morbidity and optimized reconstructive potential.
2 Diagnostic procedures and imaging
A comprehensive history and physical examination remains the cornerstone of sound preoperative evaluation when approaching diseases of the midface. A thorough examination of the lateral nasal wall, floor, and septum, as well as the nasopharynx and oropharynx should be performed. This is done by both visual examination and palpation of the soft and bony tissues of the nose, oral cavity, oropharynx, upper lip, cheek and canine fossa. Flexible endoscopic evaluation of the nasal cavity, nasopharynx and oropharynx is essential. Careful examination of the neck for the presence of regional adenopathy is critical, as well as a complete assessment of cranial nerve function.
Today high-resolution computed tomography (CT) and magnetic resonance imaging (MRI) are critical in establishing the extent of injury or disease ( Fig 3.1-1 ).
A CT imaging allows for detailed analysis of regional bone and soft-tissue involvement. An MRI provides important information regarding the extent of invasion into peritumoral soft tissues and more accurately assess intracranial extension. It also differentiates between tumor and sinonasal mucus to show the true extent of the disease. These examination tools have not only improved the accuracy of preoperative clinical staging but also opened the door to increasingly focused surgical approaches to tumors of the midface. When addressing vascular lesions, angiography and/or CT angiography, or MRI angiography should be considered. The use of fusion PET/CT scans have little value in assessing regional disease, but in selected cases may aid in assessing regional and distant metastatic disease.
In tumor surgery, depending on the clinical problem, a biopsy is mandated to allow appropriate diagnosis and planning of a resection. At times when the tumor is inaccessible for biopsy before surgery, the surgeon must rely on an intraoperative biopsy to obtain a diagnosis before planning the extent of resection.
Careful discussion with the patient of all treatment options, in addition to associated risks and benefits of each procedure, is mandated. Considerations of possible adjuvant and/or alternative radiation and/or chemotherapy should be included within this discussion. A multidisciplinary team approach is standard today to ensure optimal outcomes in the treatment of more advanced malignancies.
3 Surgical approaches including osteotomies
Many approaches to the midface have been described, transoral, transnasal, transfacial, and coronal. These can be used alone or in combination depending on the level of access needed.
3.1 Transoral/sublabial approach
For benign lesions of the maxillary sinus, a transoral approach allows for easy access with minimal morbidity. The soft-tissue approach is usually combined with an osteotomy/ostectomy of the anterior maxillary sinus wall. For treatment of benign conditions, the bone is replaced during wound closure. In case of invasive pathologies or conditions which result in erosions of the anterior sinus wall, the wall may be replaced with a titanium mesh ( Fig 3.1-2 and Fig 3.1-3 ).
The sublabial approach provides excellent exposure to tumors of the maxillary alveolus ( Fig 3.1-4 ).
3.2 Midface degloving approach
Many lesions involving the maxilla and central midface can be removed via midfacial degloving approaches. There are some limitations, for example, when the disease extends medially superiorly or wraps around the orbital rim. This approach provides excellent exposure to both sides of the face and nose. It allows access to the pterygomaxillary space and can be enhanced by using endoscopes and image guidance. The addition of these enhancements benefits in the complete removal of lesions involving this region (ie, neurogenic tumors of cranial nerve V or juvenile angiofibromas). This approach also provides access to the pterygoids in the posterior maxilla, so osteotomies can be performed when performing orbit-sparing maxillectomy procedures. These osteotomies are combined with palatal osteotomies and anterior maxillary osteotomies (nasomaxillary and zygomaticomaxillary) and division of the soft palate attachment to the hard palate to allow en bloc removal of the maxilla ( Fig 3.1-5 ).
3.3 Transpalatal approach
Transpalatal approaches have limited use as stand-alone approaches. They may be combined with resections of the alveolar process for tumors involving the premaxilla, alveolus, and anterior floor of the nose. They may also be combined with osteotomies of the attachments to the septum or maxilla depending on tumor location to release the superior attachments. Obviously, the extent or resection is dependent on the size and location of the tumor.
Transpalatal approaches for the pituitary have also been described, but have mostly been replaced by transnasal microscopic and transnasal endoscopic approaches. Likewise, transpalatal approaches may provide primary or extended access to the nasopharynx as well as to high anterior cervical fusions. Generally, separation of the soft palate with (temporary) resection of the posterior hard palate gives more restricted access than if one separates the soft and hard palate, and then divides the soft palate in the midline. Care must be taken to preserve the vascular supply of the posterior soft palate. Extensive cautery lateral to the midline is not advised and careful retraction of the palate with stay sutures is preferable to overzealous use of self-retaining retractors. This approach is seldom needed and is best performed by an experienced craniomaxillofacial surgeon to minimize morbidity. Most lesions can be removed by other approaches especially when enhanced with endoscopic image guidance.
3.4 Transoral approach in combination with Le Fort I osteotomy
A Le Fort I osteotomy, usually done from an upper buccal/ sublabial incision, with down fracture of the inferior part of the maxilla, provides good access to the posterior nasal cavity and epipharynx, especially for vascular lesions which may require good access for bleeding control. For this approach and osteotomy, the osteotomy line in the maxilla is outlined, the anterior and lateral maxillary pillars are preplated. The miniplates are then removed, the osteotomy and down fracture are performed, and the lesions treated as indicated. After that the inferior portion of the maxilla is repositioned and fixed with typically four miniplates along the anterior and lateral pillars of the midface, as it is done in orthognathic surgery ( Fig 3.1-6 ).
3.5 Transfacial approaches
Lateral rhinotomy approach
A transfacial approach combined with a lateral rhinotomy is an excellent approach for tumors involving the nasal cavity. This allows exposure of the entire nasal cavity. Superiorly, this extends to the skull base and inferiorly to the floor of the nose. All three turbinates are also exposed. The lateral rhinotomy is still the preferred approach for tumors involving the mucosa and/or cartilage of the membranous collumella, ala and dome of the nose ( Fig 3.1-7 ).
3.6 Weber Ferguson ( Dieffenbach Weber) approach
The Weber Ferguson approach is indicated as access for tumors involving the maxilla extending superiorly to the infraorbital nerve and into the orbit. It provides a wide access to all areas of the maxilla, nose, and orbital floor. The incision line is drawn through the vermillion border, along the filtrum of the lip, extending around the base of the nose (or entering the nostril floor for a better esthetic result) and along the facial nasal groove (in the border of both esthetic units). It then extends infraorbitally 3–4 mm below the cilium to the lateral canthus. The incision can be extended laterally or superiorly as necessary for tumor removal ( Fig 3.1-8a-k ).
3.7 Access through defects after tumor ablation
Besides the traditional transfacial approaches, in scenarios where skin resection because of tumor invasion is required, this may provide good and direct access to the underlying facial bones and midface cavities such as the sinuses, nasal cavities, and orbits.
3.8 Endoscopic approaches
Open approaches are consistent with the variety of clinical scenarios that patients present to surgeons, but open approaches to the midface in combination with osteotomies can result in substantial morbidity for patients. This has engendered an expanding interest in the development of minimally invasive endoscopic, endoscopically assisted, and image-guided approaches.
Today many midface lesions can be treated via transnasal endoscopic procedures. Extensions of these procedures may also provide access to the skull base, orbit and frontal sinus. Better visualization with potentially less wide and disruptive exposure can facilitate surgical removal with less surgical morbidity. They have enhanced application when coupled with image guidance systems. They can enhance traditional approaches to assess disease extension, provide improved visualization, and provide better assessment of the complete removal of the process being treated (image guided) ( Fig 3.1-9 ).
Excellent examples of the application of modern imageguided resection techniques to neoplastic processes are being observed especially in the treatment of juvenile angiofibromas, inverted papillomas, and neurogenic tumors. Rates of recurrence and operative complications following endoscopic or endoscopic-assisted resection of juvenile angiofibromas now approximate that observed following traditional open operations. This is also true for removal of inverted papilloma and several other neoplasias involving the maxilla. The older paradigm of en bloc removal appears less rigid. Indeed, what is required is complete removal. Furthermore, the innovation of intraoperative image guidance systems used in endoscopic approaches has offered surgeons improved real time anatomical localization of their resection. This allows for complete endoscopic resection of technically challenging lesions with less potential morbidity resulting from injury of vital structures. Other applications for endoscopic image-guided approaches include medial maxillectomy for inverted papilloma, and maxillary division fifth nerve neuromas. These techniques may also be used to assist in placement of implants for trauma, treatment of exophthalmos, optic nerve decompression and cerebrospinal fluid leak repair. Importantly, it cannot be overstated that the guiding principles of endoscopic intervention should mirror those of traditional approaches to midface pathology; achieving adequate exposure as to allow for the safe and complete excision of all involved tissue is critical.
The nature of the lesion also determines whether endoscopic approaches can be used. Traditional anterior transmaxillary approaches are still required for more extensive malignant processes, which may erode through the posterior or lateral table of the maxilla, floor of orbit, and alveolus. Traditional osteotomies are commonly used in the treatment of malignant tumors and removal of hard tissues (bone tumors, teeth). Transmaxillary approaches may also provide access to lesions or disorders involving the orbit and nasopharynx. Frequently in using transmaxillary approaches for tumors not involving the anterior bony structures, the anterior bone may need to be osteotomized and replaced at the end of the ablative procedures providing better postoperative cosmetic results. The surgeon must use the approach which best addresses the patient’s disease without compromise in removal or to function and appearance.
Ultimately, the surgeon’s decision regarding whether to implement an endoscopic approach hinges on both their individual technical skill set, as well as whether complete resection can be accomplished using a minimally invasive approach. Cases must be carefully selected, and patients always counseled about the potential need for a more radical approach if their tumor is not amenable to endoscopic resection. To this end, a surgeon must always remain aware of the potential intraoperative discovery of unanticipated disease extension. Such situations may mandate modification of the operative plan, requiring a more extensive resection including for instance orbital exenteration. Likewise, an experienced team is required to provide optimal outcomes, treatment for malignant tumors is best discussed and consented in a tumor board.
4 Complications and pitfalls
Complications resulting from midface approaches and osteotomies have largely been divided into four categories; namely facial, intraorbital, intraoral, and vascular [Lofchy et al, 1998]. In brief, these may include bleeding, ecchymosis, infection, hardware-related complication, infraorbital nerve impairments, epiphora, oroantral fistulae, extraocular muscle weakness/entrapment, anosmia, cerebrospinal fluid leak, and facial scar retraction and more rarely blindness.
Osteotomies performed endoscopically are undertaken with well-defined risk of minor and major complications as well. It is important to remember that with ever increasing use of endoscopic and image-guided approaches to the resection of midface and maxillary tumors, there is no substitute for surgeon experience and excellent operative exposure. As such, the surgeon must always remain cognizant of his/her own level of comfort when operating using these more minimally invasive techniques, and retain a low threshold to convert to a more invasive approach when anatomical clarity is blurred. Furthermore, when treating complex tumors, it is essential to have a team approach. A tumor board is beneficial and should integrate the expertise of multiple disciplines including—the radiologist, surgeon (ablative and reconstructive), prosthodontist, radiation oncologist, medical oncologist, pathologist, speech and swallowing specialists. Well-established multidisciplinary approaches best serve the patient who is faced with a serious disease and a potentially deforming surgery.
5 References and suggested reading
Batra PS, Luong A, Kanowitz SJ, et al. Outcomes of minimally invasive endoscopic resection of anterior skull base neoplasms. Laryngoscope. 2010 Jan;120(1):9–16. Beumer HW, Puscas L. Computer modeling and navigation in maxillofacial surgery. Curr Opin Otolaryngol Head Neck Surg. 2009 Aug;17(4):270–273. Bhattacharyya N, Orlandi RR, Grebner J, et al. Cost burden of chronic rhinosinusitis: a claims-based study. Otolaryngol Head Neck Surg. 2011 Mar;144(3):440–445. Bleier BS, Kennedy DW, Palmer JN, et al. Current management of juvenile nasopharyngeal angiofibroma: a tertiary center experience 1999-2007. Am J Rhinol Allergy. 2009 May–Jun;23(3):328–330. Carrau RL, Snyderman CH, Kassam AB, et al. Endoscopic and endoscopic-assisted surgery for juvenile angiofibroma. Laryngoscope. 2001 Mar;111(3):483–487. Heiland M, Habermann CR, Schmelzle R. Indications and limitations of intraoperative navigation in maxillofacial surgery. J Oral Maxillofac Surg. 2004 Sep;62(9):1059–1063. Herman P, Lot G, Chapot R, et al. Longterm follow-up of juvenile nasopharyngeal angiofibromas: analysis of recurrences. Laryngoscope. 1999 Jan;109(1):140–147. Levine HL. Functional endoscopic sinus surgery: evaluation, surgery, and follow-up of 250 patients. Laryngoscope. 1990 Jan;100(1):79–84. Lofchy NM, Bumsted RM. Revision and open sinus surgery. In: Cummings CW, ed. Otolaryngology —Head & Neck Surgery. 3rd ed. St Louis: Mosby; 1998:1173–1188. Nicolai P, Berlucchi M, Tomenzoli D, et al. Endoscopic surgery for juvenile angiofibroma: when and how. Laryngoscope. 2003 May;113(5):775–782. Nijmeh AD, Goodger NM, Hawkes D, et al. Image-guided navigation in oral and maxillofacial surgery. Br J Oral Maxillofac Surg. 2005 Aug;43(4):294–302. Terrell JE. Primary sinus surgery. In: Cummings CW, ed. Otolaryngology —Head & Neck Surgery. 3rd ed. St Louis: Mosby; 1998:1145–1172. Welch KC, Stankiewicz JA. A contemporary review of endoscopic sinus surgery: techniques, tools, and outcomes. Laryngoscope. 2009 Nov;119(11):2258–2268.
3.2 Midface resection and reconstruction
The importance of the central portion of the face, including palate, cheek, maxilla, upper lip, orbit, and nose cannot be underestimated. It is the functional and esthetic cornerstone of the mid-facial unit and includes each of the key mid-facial elements. The maxilla functions as the structural support between the skull base and the occlusal plane, resisting and absorbing the forces of mastication, anchoring the dentition, separating the oral and nasal cavities, supporting the globe and the soft-tissue envelope and its mimetic musculature. The soft tissues of the midface are supported by the maxilla which esthetically provides much of the facial appearance unique to each individual and serving as an icon for the whole person. Due to the disparate shapes and sizes of tumors affecting the maxilla and the complex surgical anatomy, the broad category of “maxillectomy” encompasses a group of diverse defects that range from a small oro-antral or oronasal fistula to a large cavity, bounded by the tongue inferiorly and the anterior skull base superiorly. Tumors treated by maxillectomy are rarely confined by the bony walls of the maxilla itself ( Fig 3.2-1 ); thus, resection of adjacent tissues in the velum, palate, midface, and orbits is commonly performed simultaneously. The morbidity of maxillectomy defects is rarely trivial. It potentially includes impairment of deglutition and nutrition, ocular function and vision, speech and communication, self-image and mental health, as well as maintenance of hygiene and social acceptability. Clearly, when one or all the functions of the maxilla are lost, a return to good quality of life depends on the degree to which these functions are reconstituted.
The goal of reconstruction is always to replace the form and function of native tissue. Ideal reconstruction in the midface in particular requires the following goals be met. They are in order of importance [Triana et al, 2000; Brown et al, 2000]: (1) healed wound; (2) separation of the oral and nasal cavities; (3) restoration of maxillary buttresses; (4) restoration of functional dentition, mastication, and deglutition; (5) restauration of globe position or cosmetical rehabilitation of an exenterated cavity; (6) maintain a patent nasal airway; (7) support and suspend adynamic facial soft tissues, including avoidance of ectropion; and (8) restore midfacial contour.
2 Indications and planning
Indications for partial or total maxillectomies mostly come from tumor surgery, primarily from malignant tumors. However, maxillary defects may also be congenital or the result of extensive facial trauma, especially shotgun injuries.
For reconstructive purposes, several midface defect classification systems have been developed. The classification according to Brown and Shaw is shown [Brown et al, 2010] [Brown et al, 2000; Cordeiro et al, 2000] ( Fig 3.2-2 ).
3 Diagnosis and imaging
See chapter 3.1, paragraph 2, for details.
4 Resection and reconstruction of the midface
Resection of midface structures imposes significant functional and esthetic consequences on the patient; therefore, they require reconstruction. It is crucial for a surgeon performing ablative surgery in this area to be familiar with the various reconstructive options even though that skill set may be provided by other reconstructive surgeons. Therefore, an overview is given at the beginning of this chapter.
Placement of a maxillary prosthesis is one traditional and reliable method to obturate maxillary defects [McGregor et al, 1986; Wells et al, 1995] ( Fig 3.2-3 ). The prosthesis restores the oral/nasal separation, which is a fundamental principle necessary for speaking and swallowing. Dentition can be included for chewing and appearance. The surgical complexity and length of operative procedure is less with obturator compared with tissue reconstructions. A prosthesis may also be fashioned to restore maxillary as well as nasal, orbital, and ocular defects.
These larger prostheses depend significantly on support from native tissues, and are compromised when native hard-tissue support is lacking. In particular, the status of the canine and molar teeth is important for the retention of a prosthesis. Depending on the defect, orbitofacial and dental prostheses may be used either alone or in addition to surgical flaps. For individuals reconstructed with a maxillary prosthesis only, a cheek packing is left for 7 days postoperatively and the patient will need to receive appropriate gram-positive antibiotic coverage while the packing is retained. On returning to clinic, he/she is seen by the CMF prosthodontist; the packing is removed, the cavity is cleaned and inspected and after that an obturator is manufactured and the patient is started on frequent nasal saline irrigations and home humidification. Over time, the maxillary prosthesis can be altered to “best fit” the evolving defect.
Nevertheless, prosthetic rehabilitation has significant shortcomings and patients may become dissatisfied for several reasons. Speech and swallowing require use of the device, and the device needs frequent removal and cleaning for hygiene, which may be cumbersome and technically difficult, especially for the elderly or those left with monocular vision. Poor retention due to denture bulkiness, poor residual dentition (both quality and quantity), and poor or deficient retentive surfaces can create leakage and oronasal regurgitation. In addition, as more of the zygomatic prominence is lost, the esthetic success and stability of the prosthesis is decreased. Radiation also has a negative impact on the comfort and retention of the obturator as well as the quality of underlying tissues to support it. Although initial use of a prosthesis does not preclude future tissue reconstruction, performing immediate reconstruction is technically easier than secondary procedures. Additionally, immediate reconstruction of large defects averts significant psychological and emotional distress because of disfigurement during a delay period. The theoretical advantage in tumor surveillance with prostheses compared with flap coverage remains unproved, and this is likely due to the accuracy and availability of modern imaging modalities that allow for accurate assessment of the resection bed without direct inspection [Robb et al, 2001].
In the 1980s, development of microvascular techniques allowed for free tissue transfers, yielding a tremendous improvement in the ability to resect and reconstruct in a single stage without the limitations of reach and orientation of regional pedicled flaps. These techniques allow a wide variety of donor tissue types to be used, permitting the surgeon to customize the reconstruction to match the defect. The various nuances of soft tissue and osseous needs (shape, bulk, and quality) can be incorporated into the reconstructive plan. Various free tissue transfer donor sites have been described for maxillectomy defects, including radial forearm [Marshall et al, 2003], rectus abdominis [Browne et al, 1999], fibula [Yim et al, 1994; Futran et al, 2002], scapular system [Swartz et al, 1986; Uglesic et al, 2000], and iliac crest [Brown, 1996; Genden et al, 2001]. Flap selection should be determined by various factors. The amount, location, and quality of residual bone in the midface, the quality of the existing dentition and/or denture bearing alveolar arch, determine whether a bonecontaining flap is necessary. Ideally, skin, soft tissue, mucosa, and bone needs are matched to the characteristics of the appropriate flap before undertaking a reconstructive procedure. Length of the vascular pedicle, thickness or thinness of the skin, muscle, and subcutaneous fat, the volume of the tissues available, the durability and thickness of the bone and donor-site morbidity are all important factors that must be considered.
When only the soft tissues of the alveolus are reconstructed, conventional dentures may provide functional dentition if adequate teeth and/or retentive surfaces are available to provide stability. In many cases, soft-tissue reconstruction alone results in a flatter surface of maxillary arch than in the native condition. Blunted neo-alveolar contours are created and there is loss of the gingival buccal sulcus and palatal arch depth. This results in a ‘trampoline-like’ surface so that the reconstructed maxilla functions poorly to retain a denture [Funk et al, 1998; Futran, 2001] ( Fig 3.2-4 ). If sufficient underlying bone is available, osseointegrated implants may overcome this problem, but reconstruction of a large composite defect with soft tissue alone is done at the expense of dental prosthetic rehabilitative options. Soft-tissue free flap reconstruction of the maxilla should be reserved for patients who retain adequate dentition for mastication and/ or patients who do not agree to the rigors of more complex reconstructive procedures [Cordeiro et al, 2000].
Alternatively, bony reconstruction partly restores the 3-D alveolar ridge and allows use of osseointegrated implants for functional dentition when adequate bone stock is replaced [Triana et al, 2000; Futran et al, 1999] ( Fig 3.2-5 ). Free flaps with sufficient bone stock to support osseointegrative implantation include the fibula, iliac crest, and sometimes, the scapula. The radial forearm free flap may be harvested with a bony component but the length and width of the bone available limit its use to small anterior defects not requiring implantation.
4.1 Maxillectomy with orbital preser vation
In extended maxillary defects, in addition to the considerable task of restoring oral functions, reconstitution of an inferior orbital wall and zygoma become a paramount consideration ( Fig 3.2-6 ). Without adequate support of the orbit, enophthalmos, hypophthalmos, and diplopia may result. Reconstruction of the orbital floor is necessary to prevent dystopia and to preserve eye function postoperatively. The reconstructive tasks for this defect are, therefore, technically more challenging than when the orbital contents have been resected. Soft-tissue pedicled flaps, such as the temporalis flap rotated through the defect from the osteotomized zygomatic arch, are useful in patients unable to undergo free tissue transfer. The addition of vascularized calvarial bone to the temporalis flap may also provide bone for orbital support in these patients but the geometry of getting the bone and soft tissue each into the right place may be difficult to accomplish [Parhiscar et al, 2002]. Access to the orbital floor and infraorbital rim to insert temporalis flaps requires at least a partial resection of the lateral maxilla, which may weaken the important zygomaticomaxillary buttress. However, this flap places the facial nerve at risk, particularly in the upper division, and results in an unnatural appearing temporal depression. This could be an advantage in situations where just thin bony reconstruction is needed with minimal soft-tissue bulk. Given that this is rarely the case in total maxillectomy defects, this option can be combined with other soft-tissue flaps that could then provide bulk and be fashioned independently from the bony reconstruction.
Because of the volume required to fill the midface contours, many authors have recommended soft-tissue free flaps to obtain a sealed palate and achieve an esthetically satisfactory recontouring of the face and cheek soft tissues [Marshall et al, 2003; Browne et al, 1999; Cordeiro et al, 2000; Cordeiro et al, 2000]. Preference for fat, fascia, and skin as donor material limits the unpredictable atrophy (30–90%) associated with denervated muscle-alone. Soft-tissue-alone reconstructions, however, do not address the maxillary bony skeleton, particularly the orbit, zygoma, and alveolus. Nonvascularized bone or alloplasts have been advocated to improve globe position and bone support, but bone may undergo substantial resorption ( Fig 3.2-7a–b ). The remainder of the defect is filled with vascularized free tissues ( Fig 3.2-7c ). Muscle-alone flaps should be avoided as they do not provide a lasting solution because of atrophy.
Vascularized osteomusculocutaneous free flaps have the advantage of better infection resistance than nonvascularized bone graft reconstructions and are better able to maintain bony volume. For total maxillectomy defects with orbital preservation, the subscapular system of flaps, while technically more complex, offers perhaps the greatest versatility in flap reconstruction [Swartz et al, 1986; Uglesic et al, 2000]. Replacement of the alveolar arch inferiorly with the lateral scapula (supplied by the circumflex scapular artery) and the orbital floor and rim with the scapular tip (supplied by the angular branch of the thoracodorsal artery) suits this reconstruction need well ( Fig 3.2-8 ). The thoracodorsal artery supplies the latissimus dorsi muscle and overlying tissue, which may be harvested partially or completely for a wide range of soft-tissue reconstructive needs. Furthermore, each of the two components of this flap may be rotated independently of each other. In the series by Triana et al , various flaps based on the subscapular system of vessels were used to reconstruct maxillectomy defects in ten patients. Dental and/or orbital restoration was performed in four of these patients with the use of osseointegrated implants. Schliephake  found that it is difficult to tailor the bone in a fashion that simultaneously restores the malar prominence, the infraorbital rim, and the maxillary wall, and at the same time place the lateral border of the scapula in an appropriate position for placement of these implants. Miles et al  have described the use of the vascularized scapular tip flap to restore the palate or the zygomatic contour with the scapular soft tissue (fat, fascia, and skin) filling the remainder of the maxillary defect. The scapular bone may not always be suitable for placement of osseointegrated implants, unless secondary bone augmentation is performed. A relative disadvantage in the use of the subscapular system include challenges to position the patient to harvest the flap simultaneously with the extirpative procedure, difficulty in orienting the bone to provide orbit, zygoma, and alveolar reconstruction and the relatively short pedicle length.
The fibular flap has sufficient bone stock and a soft pliable skin paddle that can be used for either intraoral and/or cutaneous reconstruction ( Fig 3.2-9 ). Futran et al  used the revascularized fibular osteocutaneous free flap in seven patients with total maxillectomies and orbital preservation. Superior and inferior bony support was accomplished, and cosmesis was only considered fair because of flattening in the midface. In comparison one patient in this series whose flap failed and ultimately used a prosthesis, was noted to have poor cosmesis. Osseointegrated implants were placed or planned in this entire group. The fibula bone stock is more reliably implantable than the scapula. This represents an advantage of the fibula over the scapula for this defect, although cosmesis favors the scapula.
The iliac crest free flap provides an excellent bone source for palate and maxillary reconstruction [Brown, 1996; Genden et al, 2001] ( Fig 3.2-10a ). A single block can restore the alveolus, zygomatic prominence, and infraorbital rim. This allows for excellent restoration of structure to support both the globe and a dental prosthesis ( Fig 3.2-10b–e ). It is harvested with the internal oblique muscle that restores the palatal mucosa. The disadvantages of using this flap for the maxilla are its potentially excessive bulk, limited soft-tissue mobility in relationship to the bone and short pedicle length.
4.2 Maxillectomy with orbital exenteration
When tumor resection extends from tongue to supraorbital rim, reconstructive options depend on the amount of remaining dentition. If adequate teeth and alveolar arch remain, a prosthesis may be used. The use of a prosthesis that spans the defect from the oral cavity to the orbit is subject to cheek retraction over time and poor fit as well as the distracting appearance of an unblinking, expressionless eye. These defects provide an additional challenge to the prosthodontist because of the large amount of associated dead space that is created. Reconstruction is usually ideally accomplished through the use of a bulky soft-tissue free flap, such as a rectus abdominus, latissimus dorsi or anterolateral thigh flap to fill the midface volume, including the orbit ( Fig 3.2-11a ). These flaps can be supplemented with separate free nonvascularized bone grafts for additional structural support when the zygomaticoorbital complex is removed as part of the resection. This complex reconstruction in one study resulted in a fair cosmetic result in 46% of patients, normal or near-normal speech in 77%, and limitation to a soft diet in 54% [Cordeiro et al, 2000]. To achieve adequate bone volume for the infraorbital and zygomatic region as well as the alveolar arch, any of the bony options described above can be used but adequate soft tissue must be harvested to obliterate and/or line the orbital component of the defect.
In those cases where there is intracranial communication, the skull base must be sealed as well and cranial protection provided. The advantages of autogenous tissue to seal the skull base include its durability and viability.
4.3 Total maxillectomy
In individuals undergoing total maxillectomy, defects are created with insufficient retentive surfaces and without remaining dentition to support a conventional prosthesis. It is therefore preferable to reconstruct the area with vascularized bone and soft tissue to allow for closure of the palate, and a stable base for osteointegrated dental implants. Ultimately an implant-borne prosthesis will be added. The main determinants of which flap to use are the size of the palate’s defect as well as whether there are additional areas that need bony support, such as the orbital floor or the malar eminence. Futran et al  reported a series of 27 consecutive patients receiving a fibula free flap for reconstruction of maxillectomy defects involving the palate that were not amenable to an obturator. In this group, 18 patients received implants with fabrication of prostheses. Four patients had wound complications managed successfully with local wound care and there was one flap loss. All patients had intelligible speech over the telephone and all were able to resume an oral diet, with 14 patients on a regular diet and 13 using soft diet. The fibula free flap has a large amount of available bone, long pedicle length and minimal donor site morbidity and is the most popular choice for total maxilla reconstruction. Scapula flaps can be a versatile option for more complex defects but disadvantages include somewhat thinner bone that does not as reliably accept implants. Simultaneous midface surgery and flap harvest are not feasible. The iliac crest is less frequently used but provides excellent bone stock, though it has excessive bulk and a short vascular pedicle. Nonvascularized free bone grafts when used in combination with softtissue flaps can provide structure to the face, improving contour but they have not been shown to reliably accept dental implants and in addition resorb substantially and often almost completely.
An example of a total maxillectomy requiring fibula free flap reconstruction is shown in Fig 3.2-12a–k . The maximal length of bone is harvested, and osteotomies are then performed proximally and distally to allow for shaping of the neo-maxilla ( Fig 3.2-12e ). The vascular pedicle is then passed through a tunnel created in the cheek, into the neck for microanastomosis. This tunnel is usually made in a subcutaneous plane superficial to the facial nerve branches and should be able to accommodate at least two fingers to ensure adequate space for the vessels. This is simpler than going beneath the facial musculature and also avoids potential kinking of the vessels. Miniplates are then used to secure the fibula to the medial and lateral buttresses of the remnant midfacial skeleton ( Fig 3.2-12f ). The skin paddle of the fibula is then inset to reconstruct the mucosa of the palate ( Fig 3.2-12g ). Delayed placement of osteointegrated implants, a prosthesis, and a longlasting stable result is shown in Fig 3.2-12h–k .
4.4 Donor site management
Management of each free flap donor site has been previously described in the literature. In short, the radial forearm free flap donor site should be closed with a split thickness skin graft and a bolster placed over the graft. The arm is then casted or placed in a volar splint for 7 days before removal to improve graft take. If bone is taken and the radius plated, arrange an appropriate follow-up with an orthopedic or hand specialist. After a fibula free flap, the donor lower leg should be cast with the ankle at a right angle for 5 days or 7 days if a skin graft is used at the donor site. The patients can then touch-down their body weight as tolerated. After the cast is removed, they can ambulate and work with physical therapy to optimize leg function. A splint should be placed to keep the foot at 90° to the leg when in bed. Flaps from the subscapular system require no particular rehabilitation care but closed suction drains should remain until a minimal output is achieved over several days to avoid seroma formation (minimal output less than 30 cc per day). Rectus abdominus and iliac crest donor sites require that the patient not strain or lift heavy objects for at least 2–4 weeks to avoid hernia formation.
5 Complications and pitfalls
Major potential complications from maxillary resection include substantial bleeding, especially from the retromaxillary venous plexus or the maxillary artery. A rare but significant complication is blindness following maxillectomies with preservation of the orbital content. A frequent adverse effect is sensory disturbances in the innervation areas of the infraorbital or/and zygomatic nerves. Those can be dysesthesias ranging from numbness to pain.
As a whole, free tissue transfer is relatively contraindicated in individuals with poor underlying health status or in those with a poor prognosis with expected short-term survival. In such instances, maxillary prostheses can be used in an effort to decrease operative time and morbidity. Specific contraindications also exist for each individual flap donor site. In instances where the morbidity from the flap harvest is unacceptable to the patient, a maxillary prosthesis or alternative simpler reconstructive technique should be considered. Temporoparietal fascial flaps and temporalis flaps are contraindicated in individuals where the superficial and deep temporal arteries have been sacrificed during past or the present surgical interventions. When selecting free tissue transfers, flaps with long pedicles are preferred to minimize the need for vein grafts. Upper neck recipient vessels are preferred for vessel anastomoses. Although the superficial temporal artery is reliable in most cases, the vein caliber and integrity are variable and the geometry is not ideal. A useful technique is to dissect facial vessels over the mandible, as these are excellent recipient vessels for anastomoses to bone flap vascular pedicles that are typically shorter than soft-tissue flap vascular pedicles. The surgeon must be prepared for using vein grafts, as the vascular pedicle of the flap may not always reach recipient neck vessels. A generous subcutaneous tunnel should be established between the maxilla and the neck vessels to allow for unrestricted and unkinked passage of the vascular pedicle. The coronoid process of the mandible can also be resected for additional space ( Fig 3.2-13 ). When using bone flaps, the vascular pedicle can be pinched in between the bony segments and also in the pterygoid region. Careful attention to an absence of pedicle compression in these areas is mandatory. Residual maxillary bone for rigid fixation is limited. Miniplates 1.5 or 2.0 are preferred and the zygomatic buttress and piriform aperture areas provide the best anchorage. It is also critical to be totally comfortable with the geometry of the vascular pedicle before plating the bone of the flap because once the bone is secure and/or the soft tissue is inset, any adjustments are difficult. When the eye is preserved, correct orbital position is technically challenging to achieve and a forced duction test should always be done to make sure the globe is not entrapped by the reconstruction.
When a free flap is used, it must be regularly monitored to ensure vascular integrity.
In patients where there is an intraoral mucosal skin suture line, a feeding tube should be placed at the time of surgery allowing the patient to be kept nil per os for 5–7 days. If issues develop with velopharyngeal insufficiency or dysphagia, assessment by a speech and swallowing pathologist may be indicated. When the lateral nasal wall is reconstructed, especially when a bulky soft-tissue flap is used, the nasal airway should be stented with gauze packing or a Merocel sponge for 5 days. An obturator may be necessary thereafter in certain cases.
6 References and suggested reading
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 Sep – Oct;18(5):412–421. Brown JS, Rogers SN, McNally DN, et al. A modified classification for the maxillectomy defect. Head Neck. 2000 Jan;22(1):17–26. Brown JS, Shaw RJ. Reconstruction of the maxilla and midface: introducing a new classification. Lancet Oncol. 2010 Oct;11(10):1001–1008. Browne JD, Burke AJ. Benefits of routine maxillectomy and orbital reconstruction with the rectus abdominis free flap. Otolaryngol Head Neck Surg. 1999 Sep;121(3):203–209. Cordeiro PG, Santamaria E. A classification system and algorithm for reconstruction of maxillectomy and midfacial efects. Plast Reconstr Surg. 2000 Jun;105(7):2331–2346. Cordeiro PG, Disa JJ. Challenges in midface reconstruction. Semin Surg Oncol. 2000 Oct–Nov;19(3):218–225. Funk GF, Arcuri MR, Frodel JL Jr. Functional dental rehabilitation of massive palatomaxillary defects: cases requiring free tissue transfer and osseointegrated implants. Head Neck. 1998 Jan;20(1):38–51. Futran ND, Haller JR. Considerations for free-flap reconstruction of the hard palate. Arch Otolaryngol Head Neck Surg. 1999 Jun;125(6):665–669. Futran ND, Wadsworth JT, Villaret D, et al. Midface reconstruction with the fibula free flap. Arch Otolaryngol Head Neck Surg. 2002 Feb;128(2):161–166. Futran ND. Retrospective case series of primary and secondary microvascular free tisssue transfer reconstruction of midfacial defects. J Prosthet Dent. 2001 Oct;86(4):369–376. Genden EM, Wallace D, Buchbinder D, et al. Iliac crest internal oblique osteomusculocutaneous free flap reconstruction of the postablative palatomaxillary defect. Arch Otolaryngol Head Neck Surg. 2001 Jul;127(7):854–861. Marshall DM, Amjad I, Wolfe SA. Use of the radial forearm flap for deep, central, midfacial defects. Plast Reconstr Surg. 2003 Jan;111(1):56–64; discussion 65–66. McGregor IA, McGregor FM. Cancer of the face and mouth. In: Pathology and Management for Surgeons. 1st ed. New York: Churchill Livingstone; 1986:553. Miles BA, Gilbert RW. Maxillary reconstruction with the scapular angle osteomyogenous free flap. Arch Otolaryngol Head Neck Surg. 2011 Nov; 137(11):1130–1135. Parhiscar A, Har-El G, Turk JB, et al. Temporoparietal osteofascial flap for head and neck reconstruction. J Oral Maxillofac Surg. 2002 Jun;60(6):619–622. Robb GL, Marunick MT, Martin JW, et al. Midface reconstruction: surgical reconstruction versus prosthesis. Head Neck. 2001 Jan;23(1):48–58. Schliephake H. Revascularized tissue transfer for the repair of complex midfacial defects in oncologic patients. J Oral Maxillofac Surg. 2000 Nov;58(11):1212–1218. Swartz WM, Banis JC, Newton ED, et al. The osteocutaneous scapular flap for mandibular and maxillary reconstruction. Plast Reconstr Surg. 1986 Apr;77(4):530–545. Triana RJ, Uglesic V, Virag M, et al. Microvascular free flap reconstructive options in patients with partial and total maxillectomy defects. Arch Facial Plast Surg. 2000 Apr–Jun;2(2):91–101. Uglesic V, Virag M, Varga S, et al. Reconstruction following radical maxillectomy with flaps supplied by the subscapular artery. J Craniomaxillofac Surg. 2000 Jun;28(3):153–160. Wells MD, Luce EA. Reconstruction of midfacial defects after surgical resection of malignancies. Clin Plast Surg. 1995 Jan;22(1):79–89. Yim KK, Wei FC. Fibula osteoseptocutaneous free flap in maxillary reconstruction. Microsurgery. 1994;15(5):353–357.
3.3 Ablative and reconstructive surgery of the orbit
1.1 Introduction and history
In addition to the eyeball, the orbit with its bony walls contains the eye muscles and nerves, fatty tissue and glandular structures of all germ layers. Therefore, various types of tumors can be found in the eye socket that are often associated with complex treatment requirements.
The most common symptom of orbital masses is exophthalmos. In addition to the visible protrusion of the globe, double vision, motility disorders, and a reduction in visual acuity, lateral and/or medial displacement and rotation of the eyeball may indicate an orbital tumor. Until the 19th century, orbital tumors, if they were operated on at all, were almost always treated by exenteration regardless of their pathology.
Advances in anesthesia and the introduction of osteotomy techniques have expanded the options for operations inside the orbit. In 1888, Krönlein was the first to describe the temporary resection of the lateral orbital wall for the removal of a dermoid while maintaining the eyeball. The mobilized piece of bone pedicled on the periosteum healed without any problems after tumor removal [Krönlein, 1888].
In 1941, Dandy could extirpate a meningioma in the optic canal for the first time via a transcranial access route after removing the orbital roof. Dandy subsequently proclaimed that this access route should be used for all orbital tumors [Dandy, 1941]. He even performed the first cranial bone graft, which he used in reconstruction.
Today, if an orbital lesion is suspected, operations can be planned based on computed tomographic (CT) scans and magnetic resonance imaging (MRI) procedures. The localization and size of the tumor and its anatomical link to the adjacent structures determines the most appropriate approach for the operation on a case-by-case basis. The globe is preserved if possible. The use of intraoperative navigation techniques can facilitate the removal of orbital tumors while maintaining function.
1.2 Etiology and epidemiology
The basis for exophthalmos in almost 50% of cases is endocrine orbitopathy, followed by inflammatory orbital pseudotumors. With few exceptions, the disease occurs on both sides. In contrast to this, orbital pseudotumors are responsible for approximately 16% of all one-sided cases of exophthalmos [Jones et al, 1979].
True orbital tumors are rare. The incidence varies between 3 and 20 cases per 1,000,000 people [Eldrup-Jörgensen, 1970; Henderson, 1987].
Epithelial neoplasias may originate from the conjunctiva or the lids but also from the lacrimal glands or the choroid. In terms of numbers, adenomas are the most common epithelial lacrimal gland tumors but carcinomas and other malignancies are also observed. Epidermoid cysts are typically localized in the orbit. Benign neurogenic tumors in the orbit that arise from the outer germ layer are also observed.
Mesenchymal tumors can originate from the extraocular muscles, the fatty tissue, the orbital vessels and more rarely the orbital bones. Here, the diagnostic spectrum ranges from benign cavernous angiomas, lipomas and osteomas to sarcomas and malignant lymphomas.
The most important and largest group of malignant neoplasias during childhood are rhabdomyosarcomas. However, benign orbital diseases and orbital dermoid are even more common in numbers and can make operations during early childhood a necessity.
In adults, endocrine orbitopathy is the most common orbital mass. Malignant lymphomas are observed frequently in patients older than 60 years [Shields et al, 2008].
In addition to this, orbital metastases and various primary tumors are also observed. Extension of sinonasal carcinomas may happen and can penetrate the orbit from the maxillary, ethmoid and/or frontal sinuses. Metastases, for instance from breast carcinomas or melanomas, are also observed and sometimes first occur more than 10 years after the primary treatment as an isolated manifestation.
2 Treatment principles
2.1 Interdisciplinary treatment concepts
The treatment of orbital masses and tumors should be an interdisciplinary task. Ophthalmology is usually the first point of contact for a patient affected by a tumor of the orbit. Frequently, an interdisciplinary treatment concept involves surgical and nonsurgical specialties. Common collaboration partners for orbital surgery includes, neurosurgeons, craniomaxillofacial surgeons, radiation oncologists, and medical oncologists in addition to ophthalmologists.
2.2 Presurgical diagnostics
The clinical symptoms of orbital tumors are often nonspecific and only rarely indicative of the diagnosis. Conclusions can be drawn about the location of the tumor based on a visible displacement of the globe, motility disorders, double vision, ocular pain or a reduction of visual acuity.
A complete ophthalmological evaluation includes assessment of visual acuity, motility and visual field testing. If applicable, it can be expanded by the determination of visually evoked potentials and eye pressure measurements that provide important results relating to the preoperative functional status of the diseased orbit. The patency and function of the lacrimal system should also be evaluated, as should ocular lubrication.
The CT and/or MRI show the exact location of the tumor and are indispensable in most cases.
2.3 Treatment principles
With the aid of modern imaging techniques for preoperative localization, the most gentle and accurate operative access route for each individual case can be determined and the risk of complications significantly reduced. A clear operative field with a wide osteotomy of the orbital walls prevents unnecessary intraoperative compression of the orbital contents, and significantly reduces postoperative dysfunction. It is also necessary to avoid long periods of traction on the globe or orbital muscles during the operation.
3 Surgical techniques
3.1 Biopsy and surgical planning
The confirmation of a diagnosis by means of a biopsy before the planning of a specific treatment is standard of care.
However, in the case of tumors in the retrobulbar area, it can be necessary to use complicated access routes to harvest representative tissue. The surgeon is then faced with the difficult decision of whether to remove the tumor entirely when first accessing the area. The depiction of the lesion in the MRI/CT image performed to plan the operation is also used for guidance. When there is a clear delineation between the tumor and the surrounding structures, an attempt should be made at primary total extirpation. This applies to most cavernous angiomas and many neurofibromas in the orbit.
An initial biopsy is a contraindication in the case of pleomorphic adenomas of the lacrimal gland as a significantly increased rate of recurrence is to be expected in the case of prior sample excision [Front et al, 1978; Henderson, 1987; Wright et al, 1992].
If epidermoid or dermoid cysts are expected because of the clinical presentation and imaging, the mass should be enucleated in total because biopsy may lead to a leakage of the contents of the cystic lesions and subsequent contamination of the orbital tissues. This may result in pronounced orbital inflammation and an increased rate of recurrence despite the subsequent extirpation of the cysts [Bartlett et al, 1993; Shermann et al, 1984].
3.2 Surgical approaches and techniques
3.2.1 Orbitotomies without osteotomy
Anterior orbitotomies with no additional osteotomies are suitable for sample biopsies and for encapsulated tumors in the anterior third of the orbit and with some limitations in the central third. In anterior orbitotomies without osteotomy of bony orbital walls, a distinction is made between transseptal and transperiosteal access routes.
In the transseptal approach, the fibers of the orbicularis oculi muscle are split in the direction of flow via an incision in the natural creases of the lid. Then the orbital septum is examined and opened ( Fig 3.3-1 ). This operative technique is particularly suitable for dermoid cysts during childhood that are often localized in front of and behind the orbital septum. Difficulties can arise because benign tumors slide back into the depths of the orbit when an attempt is made to remove them, so it can be difficult to grip them.
Transperiosteal approaches for sample biopsies of undefined tumors are an alternative approach in case the mass is not located close to the skin. With this approach, the contact area between the anterior end of the orbit and the lids remain undisturbed.
The skin incision is either made as an inferiormedial brow, lateral brow, orbital rim, mid eyelid, subciliary, or transconjunctival. The latter can, if necessary, be extended by a lateral canthotomy ( Fig 3.3-2 ). The orbital septum remains intact in this process. After the incision of the periosteum, the orbital wall close to the tumor is exposed, the periorbital tissue is split in a sagittal direction and the orbital tumor is exposed. To do this, a sufficiently large incision must be made in the periorbital tissue (normally 90° of the orbital circumference). The subsequent closure of the wound is carried out in all anatomical layers in combination with a deep silicone drain.
In single sample biopsies, the anterior periorbital area should remain intact to prevent a prolapse of the tumor out of the orbit.
3.2.2 Orbitotomies with osteotomy
Without the temporary removal of one or more orbital walls it is difficult to operate adequately on tumors in the central and posterior third of the orbit, if they are located inside the cone-shaped muscles of the orbit. In principle, all osteotomies should be carried out with fine saw blades or piezoelectric devices. The repositioning and stabilization of the osteotomy segment is then carried out using two single microscrews or microosteosynthesis plates 1.0 or 1.3.
220.127.116.11 Lateral orbitotomy
Since lacrimal gland tumors and most primary orbital tumors are both generally located lateral to the optic nerve, this access route frequently offers ideal conditions for removing tumors while maintaining function. In all orbitotomies with temporary removal of the lateral and/or superior orbital wall, a coronal incision is advantageous. The skin incision is taken down to the preauricular region on the tumor side. A subgaleal/epiperiosteal dissection up to approximately 2 cm above the eyebrow is performed ( Fig 3.3-3a ). At the height of the upper edge of the tragal cartilage, the external temporalis muscle fascia is incised and the incision is extended via the crista temporalis through the frontal periosteum to the contralateral side ( Fig 3.3-3b ).
The course of the frontal branch of the facial nerve is localized using an electrical nerve stimulator. Dissection between the layers of the superficial and deep temporal fascia or under the anterior layer of the deep temporal fascia in the subfascial fat and the subperiostal frontal dissection guarantees reliable protection of this nerve and broad subperiostal exposure of the orbital rim. The frontal branch of the trigeminal nerve is then dissected from or released from the supraorbital foramen by means of chisel osteotomy and shifted into the orbit at the same time as the periorbital periosteum is detached (normally 270° of the orbital circumference). The temporalis muscle is released from the crista temporalis in the anterior third of the muscle and deflected in a dorsal (posterior) direction. It is recommended that a small rim of the muscle be left in the muscle’s attachment to the crista temporalis for later suturing of the muscle to its insertion. The temporal fossa is completely exposed including the lateral orbit wall. A slight angular osteotomy is carried out through the lateral orbital rim ( Fig 3.3-4a ) down to the inferior orbital fissure. From there, a separation of the lateral orbital wall as far dorsal as possible in the junction between the lateral orbital wall and the temporal bone is performed. The saw cut runs above the frontozygomatic suture. The osteotomy is completed with osteotomes and the lateral segment of the orbit is temporarily removed ( Fig 3.3-4b ). The surgical assistant controls the orbital penetration depth of the saw blade during the osteotomy and protects the orbital content with a spatula.
18.104.22.168 Extended frontolateral orbitotomy
Tumors located in the intraconal and extraconal regions can be removed in a gentle manner via an extended frontolateral orbitotomy. Depending on the need, the lateral orbitotomy can be extended on an individual basis in a supraorbital and caudal lateral direction. The temporary removal of one or more orbital walls, if applicable with the zygoma and/or parts of the supraorbital edge enables clear and expanded access to the retrobulbar region. In doing this, the osteotomy is guided as a V-shape through the zygoma, and the zygomatic arches are detached from the articular tubercle at the temporomandibular joint. In the supraorbital area, the saw placement is supraorbital through the frontal bone.
22.214.171.124 Inferior orbitotomy
A temporary osteotomy of the infraorbital rim is used to expose tumors in the central and posterior thirds of the orbit caudal to the optic nerve. Above the infraorbital nerve, the bone can be mobilized. If a larger access route is needed, the infraorbital nerve, which runs directly through the operative area, must be completely freed from the mobilized segment ( Fig 3.3-5 ). If necessary in the case of tumor expansion far into the medial/caudal direction, an inferior orbitotomy can be combined with an extended superolateral orbitotomy.
126.96.36.199 Medial orbitotomy
Medial orbitotomies are mostly carried out transnasally or transethmoidally. The operative technique corresponds to that of classic sinus surgery but is always osteoclastic and contains the risk of a postoperative enophthalmos. The indication is therefore present mostly in the case of endocrine orbitopathy, in which the existing exophthalmos should be corrected anyway. An alternative to the transnasal procedure is the transconjunctival/transcaruncular approach. It can be used provided there is strict protection of the nasolacrimal duct and the medial strip attachment ( Fig 3.3-6 ). In combination with a lateral canthotomy, the lower lid is rendered free moving by this access route, which is why the operative technique is often referred to as “swinging eyelid approach” [McCord, 1981; Paridaens et al, 2006]. The resection of the lamina papyracea and the removal of the ethmoid mucosa, while maintaining the nasal ethmoid bone wall, can clearly be carried out in this way in endocrine orbitopathy. The connecting line between the anterior and posterior ethmoidal vessels, which are both coagulated and sharply detached from one another, defines the cranial limit of the decompression. If dissection and resection cranial to this line is performed, there is a risk of injury to the fila olfactoria and for a cerebrospinal fluid leak. The posterior ethmoidal foramen is the anatomical landmark to determine the limit of dorsal resection. As a rule the decompression ends here, as the optic nerve will enter the optic foramen 5 mm behind this point.