Plastic Surgery for Frontal Sinus Fractures Treatment & Management

The main goals of the surgical treatment of frontal sinus fractures are (1) protection of intracranial structures and the cessation of CSF leakage, (2) prevention of posttraumatic infections, and (3) restoration of facial aesthetics.

One may consider a 6-foot Caldwell view plain film prior to surgical intervention. An image is then obtained that accurately depicts the size and shape of the patient's frontal sinuses. This film is then sterilized and used as a template to mark the exact location of the frontal sinuses intraoperatively when the frontal bone is exposed. The film assists in designing a precise osteoplastic flap.

A study by Lee et al indicated that in patients undergoing repair of anterior table frontal sinus fractures, the use of computed tomography (CT)-scan guidance permits more accurate osteotomies and elevations of the anterior table than do the use of plain radiographic templates or a “cut-as-you-go” technique. The study, which involved 29 patients with acute, traumatic anterior table frontal sinus fractures and nasofrontal duct injury, found that osteotomies in the CT-scan guidance patients were 95% accurate, compared with 85% and 72.5% accurate in the plain radiographic template and cut-as-you-go patient groups, respectively. ^[41]

Appropriate consent must be obtained from the patient preoperatively. Sensation of the forehead must be documented, and the surgical approach must be determined prior to surgery. ^{[42, 43, 44]} Risks of the chosen approach must be discussed. For example, if the sinuses are to be explored via a bicoronal approach, frontal numbness, temporal hollowing, and scarring should be addressed.

The frontal sinus can be approached in many ways. Exposure through existing lacerations should be attempted first, but incisions through existing soft tissue defects or through the upper eyelid may provide limited exposure and access. The bicoronal incision offers better exposure of the frontal sinus and more easily permits the use of osteoplastic flaps and grafting materials for sinus obliteration. Some authors propose the pretrichial incision as a more aesthetic and equally valuable incision in particular situations. ^[45]

An endoscopic approach may also be used in certain cases. This approach decreases surgical and recovery time and avoids a large external bicoronal incision. ^[22] The use of this technique, while previously limited to the treatment of isolated simple anterior wall fractures, ^{[46, 47]} has now expanded to the repair of posterior table fractures with good results. ^[48] Computer-aided medical modeling has been described to facilitate access to the frontal sinus in complex cases. In this technique, 3-dimensional maxillofacial reconstruction technology is used to create a cutting guide, which outlines the anterior table. It is placed on the skull intraoperatively to aid the surgeon in precise cutting of the borders of the anterior table at its junction with the surrounding frontal bone. ^[49]

Standard practice is to repair fractures of the anterior wall if significant displacement is causing an external cosmetic deformity. The risk of cosmetic deformity is increased if the fracture depth is greater than 4 mm. ^[50] Exploration of the frontal sinus is indicated for nasofrontal duct injury when the fracture involves the floor of the sinus or the anterior ethmoid complex. After excluding nasofrontal duct injury, the anterior table should be repaired, most commonly with titanium or absorbable miniplates.If a large anterior table defect exists or the degree of comminution is high, grafting with calvarial cancellous bone is recommended. Iliac bone grafts have also been used with success. ^[51] The presence of improperly reduced segments, retained sinus bony fragments or foreign bodies, damaged sinus mucosa, and, in some studies, the use of synthetic grafting materials such as methyl methacrylate or hydroxyapatite may lead to infection. ^[18] Thus, one should take care to appropriatelyexplore,clean out, and reduce the frontal sinus fracture prior to repair.

Attempts to confirm nasofrontal duct injury are performed intraoperatively. The duct orifice may be probed gently. Alternatively, fluorescein dye or methylene blue may be administered in the duct after mucosal vasoconstriction. Duct obstruction is confirmed if fluorescein (or methylene blue) fails to emerge in the nose. ^[52] Alternatively, the nasofrontal duct orifice may be visualized indirectly with an endoscope through either the existing fracture site or a frontal trephination.

After confirmation of nasofrontal duct obstruction, most authors recommend ablation of the sinus. ^{[3, 14, 18, 19, 20, 21, 23, 24, 35]} Nasofrontal duct repair may also be attempted by intubating the duct for several weeks as described by Luce. ^[52] This approach may be associated with a 30% failure rate of duct patency after removal of the catheter, and, thus, is no longer commonly performed. Ablation is considered to be the safer treatment in the presence of nasofrontal duct injury because attempts to save an injured duct may be riskier in the long-term. ^{[14, 15]} Depending on the degree of comminution of the posterior table, cranialization is also an option for the treatment of nasofrontal duct injury and obstruction. Newer protocols involving sinus preservation with endoscopic management of the nasofrontal duct have been described for specific cases. Proponents argue that sinus preservation may decrease morbidity, operative time, and risk of bone devitalization,as well as allowing the surgeon to endoscopically evaluate the sinus postoperatively. Larger studies are needed to evaluate these claims. ^[53]

Gross CSF rhinorrhea is usually indicative of a dural tear and of injury either to the posterior table or, more commonly, the posterior inferior thin, bony cribriform plate. An exploration of these injuries is recommended, and, if possible, the dura should be repaired. Sinus cranialization or obliteration has been shown to be effective for management of the CSF fistula. ^{[32, 54]} Cranialization may be more beneficial in patients with severe comminution.

Folded pericranial flaps have been described to separate the nasal and frontal cavities in patients with injury to the cribriform plate. ^[12] These appear to prevent late complications that may occur from cribriform and dural injuries, such as meningitis and brain abscess. ^{[12, 21]}

Multiple materials, both autogenous and alloplastic, have been described for frontal sinus obliteration. Autogenous materials that have been used include fat, bone, muscle, and fascia. Alloplastic materials include Proplast, acrylic resin, Gelfoam, and methyl methacrylate. Overall, autogenous materials appear to be more successful than alloplastic materials in achieving obliteration and preventing long-term complications. ^[28] Anterior pericranial flaps have been suggested for frontal sinus and nasofrontal sinus duct obliteration owing to their benefits of vascularity and viability over avascular grafts such as fat, muscle, or bone. ^{[55, 56]} Latissimus dorsi myocutaneous free flaps have also been described for frontal sinus obliteration if local flaps are unavailable or infected. ^[57]

Certain procedures must be followed to ensure appropriate obliteration of the sinus and prevention of long-term sequelae, regardless of the type of material used. ^[23] First, the sinus mucosa must be completely removed. For this purpose, the use of surgical loupes and microscopes has been recommended. Second, all inner cortex bone should be removed from the sinus. Mucosa in the human frontal sinus is able to invaginate into pits of inner cortex bone. Donald described these as the vascular pits of Breschet. ^[58] Failure to remove mucosa from these pits can possibly lead to entrapment and late formation of mucoceles. To achieve this, a high-speed burr is recommended. Last, the nasofrontal duct should be occluded using either bone or pericranial fascia. A 20-year retrospective study by Pollock et al demonstrated a low complication rate of 6% after cranialization, which the authors attributed to thorough sinus mucosal debridement, complete obliteration of the nasofrontal duct, and avoidance of avascularbarriers such as abdominal fat. ^[59]

Isolated, depressed anterior table fractures without nasofrontal duct injury may be percutaneously reduced using a bony tapper device. The tapper is inserted into the depressed bone through a 3-mm incision without subperiosteal dissection. Traction is used for reduction. In a study by Yoo et al, of 13 patients who underwent percutaneous anterior table reduction, only 1 had a complication due to the procedure (pneumocephalus from involvement of posterior table). Alternatively, 2-mm screws can be used for simple percutaneous reduction and involves manual traction using forceps. This technique may be less invasive and more cosmetically favorable in patients with this simple type of fracture. ^{[29, 30]}

Postoperatively, the patient should be instructed to avoid contact and strenuous activities. The patient should seek medical attention if any swelling, tenderness, fever, or mental status decrease occurs because these may be signs of acute frontal sinusitis, with or without meningitis, which may occur in the early postoperative period secondary to retained bony chips or foreign materials in the sinuses. The patient benefits from routine wound care instructions.

For patients who have undergone repair and/or obliteration of the frontal sinuses, close monitoring (ie, every month) is recommended for the first year after the repair and annually thereafter. CT scans should be performed annually to detect complications in early stages. ^[22] Long-term follow-up care of these patients is mandatory. ^[28]

Complications of frontal sinus fractures may be life threatening. Both early and late complications may arise. An early complication is frontal sinusitis, most commonly resulting from retained foreign bodies or bony chips in the frontal sinus. If not recognized and adequately treated, this, in turn, may lead to meningitis, osteomyelitis, orbital abscess, or brain abscess.

Late complications may occur up to a decade after the injury. ^{[18, 60, 61]} These include mucocele, mucopyocele, and delayed CSF leak with or without meningitis. For this reason, patients who have undergone repair and/or obliteration of the frontal sinuses should be monitored closely the first year after the repair and then yearly thereafter. Long-term follow-up care is mandatory for these patients. ^[28] Any complaints of frontal pressure, pain, or headache should lead to an aggressive workup. Again, CT scanning provides the most accurate diagnostic information when evaluating a patient for complications.

Overall, if frontal sinus trauma is recognized adequately and patients receive an adequate workup and treatment, their prognosis is good. The management of the nasofrontal duct is key. Stanley reported on expected outcomes following repair of frontal sinus fractures. ^[62] For all patients treated with nonobliterative frontal sinus reconstructions, the complication rate was 10%. However, in patients treated with frontal sinus obliteration, the complication rate decreased to 1%. For this reason, a low threshold apparently should be present for deciding when to obliterate the frontal sinus in patients with injury to the nasofrontal duct.

Most reports in the literature have a poor follow-up record. Some of the series seem to support the notion of a 1-3% complication rate after repair. ^{[14, 20]} The most common complication appears to be meningitis. ^[63]

In the past, frontal contour defects were common after frontal sinus reconstruction. With the advent of titanium mesh, miniplates, and new grafting techniques, the overall aesthetic prognosis for these patients is good. Recently, endoscopic approaches with closure of defects using calcium hydroxyapatite have been performed with reportedly excellent cosmesis. ^{[46, 47]}

For excellent patient education resources, visit eMedicineHealth's Headache and Migraine Center and First Aid and Injuries Center. Also, see eMedicineHealth's patient education articles, Sinus Infection and Facial Fracture.

In summary, the treatment guidelines for patients with fractures of the frontal sinus, although not uniform, are mostly well established. Controversies exist regarding timing and indications for surgical intervention and regarding the best types of surgical ablative materials and procedures.

The recent introduction of newer bony, biocompatible, synthetic replacement materials with osteoinductive and osteoconductive properties is likely to add to this discussion. Endoscopic techniques and 3-dimensional reconstruction technology ^[64] continue to develop and may play a greater role in the treatment of more extensive fractures. The methods of ablative therapy and treatment algorithms presented are simply management guidelines, which may need to be modified in individual cases. Regardless of controversies, frontal sinus surgeons must be able to recognize injuries that require aggressive treatment. They then must be able to proceed with surgical treatment that renders the frontal sinus safe in the long-term. Prevention of potentially life-threatening complications is critical.