- Email: [email protected]
subcranial and Le Fort I approach
Operative Techniques in Otolaryngology (2010) 21, 39-43
A panoramic approach to the anterior skull base—The combined subfrontal/subcranial and Le Fort I approach Terry Y. Shibuya, MD, FACS,a Randall Schoeman, MD, DDS,a Sooho Choi, MDb From the aDepartment of Head and Neck Surgery and the b Department of Neurosurgery, Southern California Permanente Medical Group, Anaheim, California. KEYWORDS Subfrontal; Subcranial; Le Fort I; Advanced head and neck tumors; Anterior skull base tumors
Surgical exposure for massive tumor of the anterior skull base can be difficult. We have combined two surgical approaches, the subfrontal/subcranial approach and the Le Fort I osteotomy approach, to provide panoramic accesses to the anterior skull base. Via this combination of exposures, we have easily accessed and resected tumors extending from the cribiform plate all the way down to the level of the upper cervical spine. Additionally, we have used the nasal endoscope and microscope to assist in our resection. This approach has several advantages, which include ease of post-resection skull base reconstruction and excellent cosmetic results by avoiding anterior facial incisions. We believe this approach should be in the armamentarium of any surgeon resecting massive anterior skull base tumor. © 2010 Elsevier Inc. All rights reserved.
Panoramic access to the anterior skull base is frequently required for massive tumors that traverse the anterior skull base and span multiple regions. Very few approaches provide wide surgical exposure that spans from the anterior cribiform plate to the upper cervical spine. Over the past 8 years, we have combined the subfrontal/subcranial approach with the Le Fort I approach simultaneously. This combination has provided a panoramic exposure of the entire anterior skull base, from cribiform to upper cervical spine. Both are easy to perform and hide all surgical incisions in the scalp and sublabial regions, thereby avoiding any facial scars. We have found that, for selectively large tumors, this combination of approaches provides excellent tumor access, hidden facial incisions, and easy reconstructive options. Raveh, in 1978, pioneered the subfrontal approach to the anterior skull base for the repair of high-velocity skull base trauma and congenital anomalies.1,2 This approach provides vertical access from the anterior ethmoid roof down to the superior clivus and horizontal access across both orbital roofs, extending toward the temporal bones laterally (Figure 1). ViAddress reprint requests and correspondence: Terry Y. Shibuya, MD, FACS, Department of Head and Neck Surgery, Southern California Permanente Medical Group, 3460 La Palma Ave, Anaheim, CA 92806. E-mail address: [email protected]. 1043-1810/$ -see front matter © 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.otot.2010.03.007
sualization of the nasal cavity and maxillary sinuses is possible as well. The subfrontal exposure allows for intra- and extradural tumor resection with minimal frontal lobe retraction. To enhance visualization of the entire clivus and upper cervical spine inferiorly, a transmaxillary or Le Fort I approach is added3 (Figure 2). In addition, the septum is mobilized in a fashion similar to a transeptal/transnasal pituitary approach after mobilizing the lower maxilla inferiorly via a Le Fort I osteotomy. This combination of techniques allows a panoramic approach to the anterior skull base.
Technique The subfrontal approach is briefly reviewed. 1. The subfrontal approach begins with a coronal incision performed from preauricular crease to preauricular crease. 2. A pericranial flap is preserved and based on the supratrochlear and supraorbital arteries for later use in reconstruction of the anterior skull base defect. The flap is carried down to the frontozygomatic suture line laterally and to the rhinion and piriform aperture medially. 3. The orbit is accessed and the periorbita elevated off the medial, superior, and lateral orbital walls (Figure 3A). The anterior ethmoidal artery is ligated.
40
Operative Techniques in Otolaryngology, Vol 21, No 1, March 2010
Le Fort I approach The Le Fort I approach is briefly reviewed.
Figure 1 The subfrontal or subcranial approach to the skull base. The arrow indicates the improved view with the subfrontal extension.
4. Osteotomies are marked out, and the size of frontal bone flap removed is dependent on the size of tumor being access/resected. Osteotomies are usually performed as follows: superior osteotomy—placed across the frontal bone in a horizontal plane; lateral osteotomies— cut from the superior osteotomy ends inferiorly down and thru the superior orbital rims bilaterally; orbital osteotomies—placed from the superior orbital rim cut 1 cm posterior into the superior orbital roof, then cut 90° medially to the medial orbital wall, then cut inferiorly down the medial orbital wall to the level of the nasolacrimal duct, then cut anteriorly and out the medial orbital wall; anterior osteotomy—placed along the nasomaxillary groove horizontally just anterior to the lacrimal duct and connected with the opposite side (Figure 3B). A final vertical osteotomy is performed anterior to the crista galli detaching the frontonasal segment. The orbit and dura are protected at all times with ribbon retractors (Figure 4A). 5. There are variations in the size of bone flap removed (Figure 4). A Raveh type I approach removes the frontonasal segment while preserving the posterior wall of the frontal sinus. The posterior wall is removed in a second step and is indicated when tumor abuts this region. A Raveh type II approach removes the frontonasal segment, which includes the posterior wall of the frontal sinus. This is performed when tumor involves the posterior wall or broader intracranial exposure is needed to access the tumor. Visualization and removal of tumor extending to the sphenoid sinus and clivus is easily achieved. For sinonasal tumors extending through the olfactory groove, the olfactory cleft may be easily keyholed and dropped inferiorly into the sinus cavity for an en bloc resection. If tumor only involves one side of the olfactory groove, the involved side may be easily visualized and resected while preserving the opposite side.
1. A sublabial incision is performed in the gingival-buccal sulcus, leaving a 5- to 7-mm cuff of mucosa for closure of the wound postoperatively. 2. The cheek is elevated off bilateral anterior maxillary sinus walls to the level of the nasal aperture and superiorly both medial and lateral to the inferior orbital nerve exiting its foramen on the anterior maxillary wall (Figure 5). 3. Next, the mucosa of the inferior nasal floor is elevated bilaterally, and the mucosa is elevated off the lower nasal septum bilaterally. This can be done via the sublabial incision or performed via a hemitransfixation incision in the right nostril (similar to performing a septoplasty). When doing this, we elevate the mucosa off the septum completely on one side and on the remaining side only elevated to 3-5 mm above the maxillary crest/cartilaginous septal junction. This will preserve the septal mucosal attachment on one side, ensuring a cartilage/mucosa vascular blood supply to one side. 4. Next, osteotomies are performed along the anterior, medial, and lateral maxillary sinus walls using an oscillating saw (Figure 6). 5. After performing the osteotomies, 1.5-mm titanium midface plates are bent, drilled, and fixed into position. This will allow for correct anatomic positioning of the maxilla prior to fracturing. The plates are then saved in cups marked with the correct anatomical position for reconstruction post tumor resection (Figure 7). 6. Next, a curved osteotome is placed in the pterygomaxillary fissure, and an osteotomy is performed on the left and right sides. 7. After this, two small self-retaining retractors are placed between the anterior maxillary osteotomies on the left
Figure 2 The transmaxillary with the Le Fort I osteotomy approach to the skull base. Lines indicate the extent of exposure.
Shibuya et al
Figure 3
Combined Subfrontal/Subcranial and Le Fort I Approach
41
The subfrontal approach. (A) Subcranial access viewed from above. (B) Osteotomies performed. FS, frontal sinus.
and right sides (Figure 8). Each is then simultaneously opened, similar to “opening a clam shell.” 8. At the base of the clam shell or posterior wall of the maxilla, the pterygoid plates are then resected carefully using Takahashi forceps, and the pterygoid muscles are released from their insertion on the plates. As this occurs, the maxilla will descend, and the self-retaining retractor can be maximally opened. 9. The septum can now be pushed to one side, and a Hardy pituitary retractor can be placed trans-septally to expose the anterior wall of the sphenoid sinus. Because the cavity is very large, the speculum lies at the level of the upper cervical spine region. To enhance exposure, we usually place two Hardy retractors on top of each other to provide enhanced retraction and exposure (Figure 9).
10. At this point, surgical exposure will be visible from the cribiform region all the way to the level of the upper cervical spine. The endoscope or microscope or both can be used to assist with tumor resection using this technique.
Reconstruction Brief review of reconstruction option: 1. Once the tumor has been resected, there are several options for reconstructing the anterior skull base. A large pericranial flap that was previously harvested with the subfrontal approach may be rotated into the defect. This
Figure 4 Raveh type 1 and 2 approaches. (A) The frontal bone flap created with the type 1 and 2 approaches. (B) Removal of the frontal bone flap and view obtained.
42
Operative Techniques in Otolaryngology, Vol 21, No 1, March 2010
Figure 7 Plating the anterior maxilla, prior to mobilizing the maxilla. (Color version of figure is available online.)
Figure 5 The facial degloving approach with exposure of the anterior maxillary sinus wall.
2.
3. 4.
5.
6.
can be used to seal the cribiform region and sphenoid sinus and line the clivus and cervical spine. If the flap is too short or inadequate in length to reach, we routinely harvest tensor fascia lata from the thigh, cutting it into strips of adequate length and width to cover the defect. We routinely place three layers of tensor over the defect in a layered fashion and use fibrin glue to secure into position. Next, the nasal mucosa is then repositioned to cover the flap or tensor. After this, the bone flaps are fixed back into position. For the maxilla, the prebend plates and screws are fixed into position. For the subfrontal area, the bone flap is stripped of any mucosa, and a diamond bur is used to bur any residual mucosa off the bone. The frontal sinus is cranialized, and the bone is secured into proper position with microplates or titanium mesh. The nose is then packed with either strip gauze coated with bacitracin ointment or nasal tampons coated with ointment. The patient is then kept intubated overnight, but will frequently have a tracheotomy placed to reduce the
Figure 6 Osteotomies of the anterior, lateral and medial maxilla, prior to fracturing. (Color version of figure is available online.)
chance of airway obstruction and prevention of a tension pneumocephalous. If there is a concern regarding a potential cerebral spinal fluid (CSF) leak, we do not routinely place suction drain in the scalp. This is to reduce the potential for the drain to create a suction fistula.
Complications To prevent a CSF leak, meticulous dural reconstruction is performed. Small dural defects are sutured shut, whereas larger defects may be repaired using an anteriorly based pericranial flap or a laterally based temporalis–pericranial flap. Either flap is rotated into the defect and used to separate the dura from the sinonasal cavity. Other options include using tensor fascia lata, temporalis fascia, lyophilized dura, or bovine pericardium to separate the regions. For large defects, a free or pedicled myocutaneous flap may be used as well. To prevent herniation of the medial orbital contents, temporalis fascia or tensor fascia lata may be used to line the medial wall. Gel foam (Pfizer, New York, NY) is then placed on top of the fascia, and xeroform gauze (Covidien, Mansfield, MA) is used to line the cavity. Bacitracin-impregnated packing is placed to hold the grafts in position for 1 week and then removed. A triple layer of tensor fascia lata has been used successfully and is very
Figure 8 Opening the maxilla with self-retaining retractors. (Color version of figure is available online.)
Shibuya et al
Combined Subfrontal/Subcranial and Le Fort I Approach
Figure 9 Placement of two Hardy retractors trans-septally, stacked on top of each other with the maxilla pushed inferiorly for improved exposure of the skull base. (Color version of figure is available online.)
effective at preventing leaks or infections. Free bone grafts to reconstruct the medial orbital wall are rarely performed. If used, they must be completely surrounded by vascularized tissue or there will be a high risk of failure. This is especially true in a previously irradiated tissue bed. The use of alloplastic materials or titanium mesh in irradiated tissue beds or soon-to-be-radiated beds is not routinely recommended due to infectious complications and extrusion of alloplastic material over time.
Discussion Panoramic exposure of the anterior skull base from cribiform to upper cervical spine is occasionally required for advanced skull base tumors. Over the past decade, we have combined two individual approaches, the subfrontal/subcranial approach with the Le Fort I approach, to provide panoramic exposure. With this combination we have been able to surgically resect a variety of very extensive tumors. We have also added the assistance of the nasal endoscope and microscope to further enhance our visualization, dissection, resection, and reconstruction. The broader exposure has allowed the surgeon to use a two-handed surgical approach while operating along the anterior skull base. Additionally,
43
the sublabial incision and coronal incision have prevented anterior facial scars and enhanced cosmetic outcome. Reconstruction of defects along this region can be quite extensive, especially if the clivus is resected and the only remaining barrier between the nasopharynx/sinus region is the dura covering the brainstem. In such instances, we have used a large pericranial flap rotated into the defect from above or used a triple layering of tensor fascia lata covering the dura. Overlying this, we rotate nasal/septal mucosa provided it is available and has not been resected. After this is completed, gel foam impregnated with bacitracin ointment is placed on top of the grafts/flap; finally, xeroform gauze with strip gauze is packed against the gel foam to hold everything in place. This is kept in position for 7 days and then removed in the office or under sedation if the patient is not cooperative or there is concern a dehiscence is present. Radiation for malignant tumor may be necessary, and it is very important that the wound has healed prior to radiation. We routinely wait 6 weeks prior to initiating this. Patient postoperative care is very important to prevent infections. Patients will frequently develop very large crusts that need to be removed. Patients are instructed to flush their nasal passage/douche with saline four to six times a day for about a week after the packing is removed. They will need to be seen on a regular basis for nasal debridement while the cavity is maturing. At times the crusting can be very adherent to the lateral nasal walls and posterior nasopharynx/ clival wall. It is not recommended to be overly vigorous in removing the posterior wall crusts, especially if the posterior bony wall has been completely removed. With time the crust will mature and soften and can be gently removed in the office. Flushing with saline is an important adjunct to loosing the scabs/crust, helping to facilitate the cavity’s maturation. In conclusion, we have found the combination of the subfrontal/subcranial approach with the Le Fort I osteotomy approach to be a very effective exposure to massive tumors extending along the anterior cranial base. The access has been panoramic in nature, allowing for excellent visualization for resection and reconstruction, while providing excellent cosmesis.
References 1. Raveh J, Laedrach K, Speiser M, et al: The subcranial approach for fronto-orbital and anteroposterior skull-base tumors. Arch Otolaryngol Head Neck Surg 119:385-393, 1993 2. Shibuya TY, Armstrong WB, Shohet J: Skull base surgery, in Ensley JF, Gutkind SJ, Jacobs JR, Lippman SM (eds): Head and Neck Cancers. San Diego, CA, Academic Press, 2003, pp 339-357 3. Brown H: The Le Fort I maxillary osteotomy. J Maxillofac Surg 14: 112-119, 1986
A panoramic approach to the anterior skull base—The combined subfrontal/subcranial and Le Fort I approach Terry Y. Shibuya, MD, FACS,a Randall Schoeman, MD, DDS,a Sooho Choi, MDb From the aDepartment of Head and Neck Surgery and the b Department of Neurosurgery, Southern California Permanente Medical Group, Anaheim, California. KEYWORDS Subfrontal; Subcranial; Le Fort I; Advanced head and neck tumors; Anterior skull base tumors
Surgical exposure for massive tumor of the anterior skull base can be difficult. We have combined two surgical approaches, the subfrontal/subcranial approach and the Le Fort I osteotomy approach, to provide panoramic accesses to the anterior skull base. Via this combination of exposures, we have easily accessed and resected tumors extending from the cribiform plate all the way down to the level of the upper cervical spine. Additionally, we have used the nasal endoscope and microscope to assist in our resection. This approach has several advantages, which include ease of post-resection skull base reconstruction and excellent cosmetic results by avoiding anterior facial incisions. We believe this approach should be in the armamentarium of any surgeon resecting massive anterior skull base tumor. © 2010 Elsevier Inc. All rights reserved.
Panoramic access to the anterior skull base is frequently required for massive tumors that traverse the anterior skull base and span multiple regions. Very few approaches provide wide surgical exposure that spans from the anterior cribiform plate to the upper cervical spine. Over the past 8 years, we have combined the subfrontal/subcranial approach with the Le Fort I approach simultaneously. This combination has provided a panoramic exposure of the entire anterior skull base, from cribiform to upper cervical spine. Both are easy to perform and hide all surgical incisions in the scalp and sublabial regions, thereby avoiding any facial scars. We have found that, for selectively large tumors, this combination of approaches provides excellent tumor access, hidden facial incisions, and easy reconstructive options. Raveh, in 1978, pioneered the subfrontal approach to the anterior skull base for the repair of high-velocity skull base trauma and congenital anomalies.1,2 This approach provides vertical access from the anterior ethmoid roof down to the superior clivus and horizontal access across both orbital roofs, extending toward the temporal bones laterally (Figure 1). ViAddress reprint requests and correspondence: Terry Y. Shibuya, MD, FACS, Department of Head and Neck Surgery, Southern California Permanente Medical Group, 3460 La Palma Ave, Anaheim, CA 92806. E-mail address: [email protected]. 1043-1810/$ -see front matter © 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.otot.2010.03.007
sualization of the nasal cavity and maxillary sinuses is possible as well. The subfrontal exposure allows for intra- and extradural tumor resection with minimal frontal lobe retraction. To enhance visualization of the entire clivus and upper cervical spine inferiorly, a transmaxillary or Le Fort I approach is added3 (Figure 2). In addition, the septum is mobilized in a fashion similar to a transeptal/transnasal pituitary approach after mobilizing the lower maxilla inferiorly via a Le Fort I osteotomy. This combination of techniques allows a panoramic approach to the anterior skull base.
Technique The subfrontal approach is briefly reviewed. 1. The subfrontal approach begins with a coronal incision performed from preauricular crease to preauricular crease. 2. A pericranial flap is preserved and based on the supratrochlear and supraorbital arteries for later use in reconstruction of the anterior skull base defect. The flap is carried down to the frontozygomatic suture line laterally and to the rhinion and piriform aperture medially. 3. The orbit is accessed and the periorbita elevated off the medial, superior, and lateral orbital walls (Figure 3A). The anterior ethmoidal artery is ligated.
40
Operative Techniques in Otolaryngology, Vol 21, No 1, March 2010
Le Fort I approach The Le Fort I approach is briefly reviewed.
Figure 1 The subfrontal or subcranial approach to the skull base. The arrow indicates the improved view with the subfrontal extension.
4. Osteotomies are marked out, and the size of frontal bone flap removed is dependent on the size of tumor being access/resected. Osteotomies are usually performed as follows: superior osteotomy—placed across the frontal bone in a horizontal plane; lateral osteotomies— cut from the superior osteotomy ends inferiorly down and thru the superior orbital rims bilaterally; orbital osteotomies—placed from the superior orbital rim cut 1 cm posterior into the superior orbital roof, then cut 90° medially to the medial orbital wall, then cut inferiorly down the medial orbital wall to the level of the nasolacrimal duct, then cut anteriorly and out the medial orbital wall; anterior osteotomy—placed along the nasomaxillary groove horizontally just anterior to the lacrimal duct and connected with the opposite side (Figure 3B). A final vertical osteotomy is performed anterior to the crista galli detaching the frontonasal segment. The orbit and dura are protected at all times with ribbon retractors (Figure 4A). 5. There are variations in the size of bone flap removed (Figure 4). A Raveh type I approach removes the frontonasal segment while preserving the posterior wall of the frontal sinus. The posterior wall is removed in a second step and is indicated when tumor abuts this region. A Raveh type II approach removes the frontonasal segment, which includes the posterior wall of the frontal sinus. This is performed when tumor involves the posterior wall or broader intracranial exposure is needed to access the tumor. Visualization and removal of tumor extending to the sphenoid sinus and clivus is easily achieved. For sinonasal tumors extending through the olfactory groove, the olfactory cleft may be easily keyholed and dropped inferiorly into the sinus cavity for an en bloc resection. If tumor only involves one side of the olfactory groove, the involved side may be easily visualized and resected while preserving the opposite side.
1. A sublabial incision is performed in the gingival-buccal sulcus, leaving a 5- to 7-mm cuff of mucosa for closure of the wound postoperatively. 2. The cheek is elevated off bilateral anterior maxillary sinus walls to the level of the nasal aperture and superiorly both medial and lateral to the inferior orbital nerve exiting its foramen on the anterior maxillary wall (Figure 5). 3. Next, the mucosa of the inferior nasal floor is elevated bilaterally, and the mucosa is elevated off the lower nasal septum bilaterally. This can be done via the sublabial incision or performed via a hemitransfixation incision in the right nostril (similar to performing a septoplasty). When doing this, we elevate the mucosa off the septum completely on one side and on the remaining side only elevated to 3-5 mm above the maxillary crest/cartilaginous septal junction. This will preserve the septal mucosal attachment on one side, ensuring a cartilage/mucosa vascular blood supply to one side. 4. Next, osteotomies are performed along the anterior, medial, and lateral maxillary sinus walls using an oscillating saw (Figure 6). 5. After performing the osteotomies, 1.5-mm titanium midface plates are bent, drilled, and fixed into position. This will allow for correct anatomic positioning of the maxilla prior to fracturing. The plates are then saved in cups marked with the correct anatomical position for reconstruction post tumor resection (Figure 7). 6. Next, a curved osteotome is placed in the pterygomaxillary fissure, and an osteotomy is performed on the left and right sides. 7. After this, two small self-retaining retractors are placed between the anterior maxillary osteotomies on the left
Figure 2 The transmaxillary with the Le Fort I osteotomy approach to the skull base. Lines indicate the extent of exposure.
Shibuya et al
Figure 3
Combined Subfrontal/Subcranial and Le Fort I Approach
41
The subfrontal approach. (A) Subcranial access viewed from above. (B) Osteotomies performed. FS, frontal sinus.
and right sides (Figure 8). Each is then simultaneously opened, similar to “opening a clam shell.” 8. At the base of the clam shell or posterior wall of the maxilla, the pterygoid plates are then resected carefully using Takahashi forceps, and the pterygoid muscles are released from their insertion on the plates. As this occurs, the maxilla will descend, and the self-retaining retractor can be maximally opened. 9. The septum can now be pushed to one side, and a Hardy pituitary retractor can be placed trans-septally to expose the anterior wall of the sphenoid sinus. Because the cavity is very large, the speculum lies at the level of the upper cervical spine region. To enhance exposure, we usually place two Hardy retractors on top of each other to provide enhanced retraction and exposure (Figure 9).
10. At this point, surgical exposure will be visible from the cribiform region all the way to the level of the upper cervical spine. The endoscope or microscope or both can be used to assist with tumor resection using this technique.
Reconstruction Brief review of reconstruction option: 1. Once the tumor has been resected, there are several options for reconstructing the anterior skull base. A large pericranial flap that was previously harvested with the subfrontal approach may be rotated into the defect. This
Figure 4 Raveh type 1 and 2 approaches. (A) The frontal bone flap created with the type 1 and 2 approaches. (B) Removal of the frontal bone flap and view obtained.
42
Operative Techniques in Otolaryngology, Vol 21, No 1, March 2010
Figure 7 Plating the anterior maxilla, prior to mobilizing the maxilla. (Color version of figure is available online.)
Figure 5 The facial degloving approach with exposure of the anterior maxillary sinus wall.
2.
3. 4.
5.
6.
can be used to seal the cribiform region and sphenoid sinus and line the clivus and cervical spine. If the flap is too short or inadequate in length to reach, we routinely harvest tensor fascia lata from the thigh, cutting it into strips of adequate length and width to cover the defect. We routinely place three layers of tensor over the defect in a layered fashion and use fibrin glue to secure into position. Next, the nasal mucosa is then repositioned to cover the flap or tensor. After this, the bone flaps are fixed back into position. For the maxilla, the prebend plates and screws are fixed into position. For the subfrontal area, the bone flap is stripped of any mucosa, and a diamond bur is used to bur any residual mucosa off the bone. The frontal sinus is cranialized, and the bone is secured into proper position with microplates or titanium mesh. The nose is then packed with either strip gauze coated with bacitracin ointment or nasal tampons coated with ointment. The patient is then kept intubated overnight, but will frequently have a tracheotomy placed to reduce the
Figure 6 Osteotomies of the anterior, lateral and medial maxilla, prior to fracturing. (Color version of figure is available online.)
chance of airway obstruction and prevention of a tension pneumocephalous. If there is a concern regarding a potential cerebral spinal fluid (CSF) leak, we do not routinely place suction drain in the scalp. This is to reduce the potential for the drain to create a suction fistula.
Complications To prevent a CSF leak, meticulous dural reconstruction is performed. Small dural defects are sutured shut, whereas larger defects may be repaired using an anteriorly based pericranial flap or a laterally based temporalis–pericranial flap. Either flap is rotated into the defect and used to separate the dura from the sinonasal cavity. Other options include using tensor fascia lata, temporalis fascia, lyophilized dura, or bovine pericardium to separate the regions. For large defects, a free or pedicled myocutaneous flap may be used as well. To prevent herniation of the medial orbital contents, temporalis fascia or tensor fascia lata may be used to line the medial wall. Gel foam (Pfizer, New York, NY) is then placed on top of the fascia, and xeroform gauze (Covidien, Mansfield, MA) is used to line the cavity. Bacitracin-impregnated packing is placed to hold the grafts in position for 1 week and then removed. A triple layer of tensor fascia lata has been used successfully and is very
Figure 8 Opening the maxilla with self-retaining retractors. (Color version of figure is available online.)
Shibuya et al
Combined Subfrontal/Subcranial and Le Fort I Approach
Figure 9 Placement of two Hardy retractors trans-septally, stacked on top of each other with the maxilla pushed inferiorly for improved exposure of the skull base. (Color version of figure is available online.)
effective at preventing leaks or infections. Free bone grafts to reconstruct the medial orbital wall are rarely performed. If used, they must be completely surrounded by vascularized tissue or there will be a high risk of failure. This is especially true in a previously irradiated tissue bed. The use of alloplastic materials or titanium mesh in irradiated tissue beds or soon-to-be-radiated beds is not routinely recommended due to infectious complications and extrusion of alloplastic material over time.
Discussion Panoramic exposure of the anterior skull base from cribiform to upper cervical spine is occasionally required for advanced skull base tumors. Over the past decade, we have combined two individual approaches, the subfrontal/subcranial approach with the Le Fort I approach, to provide panoramic exposure. With this combination we have been able to surgically resect a variety of very extensive tumors. We have also added the assistance of the nasal endoscope and microscope to further enhance our visualization, dissection, resection, and reconstruction. The broader exposure has allowed the surgeon to use a two-handed surgical approach while operating along the anterior skull base. Additionally,
43
the sublabial incision and coronal incision have prevented anterior facial scars and enhanced cosmetic outcome. Reconstruction of defects along this region can be quite extensive, especially if the clivus is resected and the only remaining barrier between the nasopharynx/sinus region is the dura covering the brainstem. In such instances, we have used a large pericranial flap rotated into the defect from above or used a triple layering of tensor fascia lata covering the dura. Overlying this, we rotate nasal/septal mucosa provided it is available and has not been resected. After this is completed, gel foam impregnated with bacitracin ointment is placed on top of the grafts/flap; finally, xeroform gauze with strip gauze is packed against the gel foam to hold everything in place. This is kept in position for 7 days and then removed in the office or under sedation if the patient is not cooperative or there is concern a dehiscence is present. Radiation for malignant tumor may be necessary, and it is very important that the wound has healed prior to radiation. We routinely wait 6 weeks prior to initiating this. Patient postoperative care is very important to prevent infections. Patients will frequently develop very large crusts that need to be removed. Patients are instructed to flush their nasal passage/douche with saline four to six times a day for about a week after the packing is removed. They will need to be seen on a regular basis for nasal debridement while the cavity is maturing. At times the crusting can be very adherent to the lateral nasal walls and posterior nasopharynx/ clival wall. It is not recommended to be overly vigorous in removing the posterior wall crusts, especially if the posterior bony wall has been completely removed. With time the crust will mature and soften and can be gently removed in the office. Flushing with saline is an important adjunct to loosing the scabs/crust, helping to facilitate the cavity’s maturation. In conclusion, we have found the combination of the subfrontal/subcranial approach with the Le Fort I osteotomy approach to be a very effective exposure to massive tumors extending along the anterior cranial base. The access has been panoramic in nature, allowing for excellent visualization for resection and reconstruction, while providing excellent cosmesis.
References 1. Raveh J, Laedrach K, Speiser M, et al: The subcranial approach for fronto-orbital and anteroposterior skull-base tumors. Arch Otolaryngol Head Neck Surg 119:385-393, 1993 2. Shibuya TY, Armstrong WB, Shohet J: Skull base surgery, in Ensley JF, Gutkind SJ, Jacobs JR, Lippman SM (eds): Head and Neck Cancers. San Diego, CA, Academic Press, 2003, pp 339-357 3. Brown H: The Le Fort I maxillary osteotomy. J Maxillofac Surg 14: 112-119, 1986