FIGURE 25.1 A. and B. Coronal and sagittal images show a large left frontoethmoid osteoma. Because of the lateral and superior extension of the lesion, an osteoplastic flap was elected. A nonobliterative approach was chosen in order to preserve the normal mucosa of the contralateral frontal sinus as well as the uninvolved mucosa of the ipsilateral side. The procedure for this patient is demonstrated in Figures 25.2 to 25.6.
Although the majority of cases of frontal sinusitis can be managed successfully using endoscopic techniques, the osteoplastic flap does remain an important alternative for revision of severe frontal sinusitis cases. In patients in whom extensive scarring renders the frontal recesses severely stenotic, an osteoplastic flap approach to the frontal sinus may be considered. Infectious complications of frontal sinusitis, such as Pott’s puffy tumor or frontal osteomyelitis, may require an osteoplastic flap to access infected frontal bone for debridement or resection. The addition of obliteration to the osteoplastic flap procedure is an option for treatment of inflammatory and infectious cases; however, a nonobliterative approach may be preferred in patients with tumors of the frontal sinus since the obliterative material may obscure detection of early recurrences of tumor and may make radiologic surveillance difficult.
Fractures of the frontal sinus may also be best managed by an open osteoplastic flap approach, allowing for direct visualization and manipulation of bony fragments of the anterior and posterior table.
CONTRAINDICATIONS
There are few absolute contraindications to osteoplastic flap surgery. In considering an obliterative versus nonobliterative approach, one must consider relative contraindications to frontal sinus obliteration. In the setting of frontal sinus trauma, posterior table fractures demonstrating extensive comminution or severe displacement are managed more favorably by frontal sinus cranialization than by frontal obliteration. In addition, when neoplasms of the frontal sinus are removed through an osteoplastic approach, radiographic surveillance of tumor recurrence will be more difficult in an obliterated compared to a nonobliterated sinus.
PREOPERATIVE PLANNING
Obliteration Versus Nonobliteration
A key decision point in preoperative planning for frontal osteoplastic flap surgery is to determine whether obliteration of the frontal sinus is indicated as an adjunctive procedure. The osteoplastic flap provides outstanding surgical exposure of the frontal sinus, but it does not necessarily need to be accompanied by stripping of the frontal sinus and obliteration, depending on the pathology being approached. There are several advantages of preserving the frontal sinus mucosa (osteoplastic flap without obliteration): (1) preservation of frontal sinus function, (2) improved ability to interpret postoperative imaging, and (3) reduced risk of chronic frontal neuropathy.
Patients with smaller tumors of the frontal sinus are, in general, good candidates for preservation of noninvolved frontal sinus mucosa, unless there is direct involvement of the frontal outflow tract by tumor that would require circumferential removal of the mucosa thereby predisposing the patient to frontal ostial stenosis. Similarly, management of trauma of the frontal sinus has trended toward more conservative approaches. Fractures of the frontal sinus requiring an osteoplastic flap for surgical exposure may not necessarily require obliteration, unless there is gross traumatic involvement of the frontal infundibula.
Choice of Obliteration Material
When obliteration is indicated, the time-tested material of choice for filling the frontal sinus is adipose tissue, usually harvested from the abdomen. Alternatively, the frontal sinus can be obliterated with hydroxyapatite cement, pericranium, or autologous bone chips.
Preoperative Imaging
Preoperative imaging should include thin section noncontrast computed tomography (CT) of the frontal sinus. Unilateral obliteration may be considered for unilateral disease. An extensively pneumatized frontal sinus will be more challenging to obliterate owing to the extended mucosal surface area of the frontal sinus that must be completely exenterated. In addition, erosion of the posterior table or floor is a relative contraindication to obliteration, owing to the difficulty of completely removing mucosa from periorbita or dura in areas of bone erosion. CT studies should be performed with a protocol enabling computer navigation, as delineation of the boundaries of the osteoplastic flap is greatly facilitated by computer navigation.
Alternatively, plain film imaging may be used to create a template to demarcate the boundaries of the frontal sinus. A 6-foot Caldwell view will produce a 1:1 image of the frontal sinus. The film may be cut out around the frontal sinus outline and sterilized as a template for making the frontal osteotomies.
SURGICAL TECHNIQUE
The patient is placed in the supine position with the head positioned 180 degrees away from anesthesia to facilitate complete access to the frontal region. The hair can be parted without shaving the scalp to prepare for the scalp incision; the hair should be bundled in rubber bands to keep the hair clear of the incision. If surgical navigation is planned, a bone-anchored navigation reference post should be placed prior to skin prep (Fig. 25.2). Tarsorrhaphy sutures or other form of eye protection should be employed.
