postoperative CT scans obtained approximately 3 months after surgery one can now clearly distinguish the separation of the anterior cranial fossa and orbital cavities from the sinus and nasal cavities inferiorly. This is particularly evident when comparing these CT scans (Figure 21) with the preoperative scans (Figure 14). It is important to obtain postoperative CT scans to confirm that adequate functional separation of these 2 cavities has been accomplished. The postoperative photograph at 6 months post injury demonstrates a relatively normal appearance after repair.

Complications

To this date, we have not encountered significant complications such as CSF leak or mucocele. However, it is certainly understood that the latter complication can occur long after the initial reconstruction. There have been no significant cosmetic deformities other than laceration scar deformities and occasional irregularities along the supraorbital rim that seem to be most commonly due to placement of fixation devices such as mesh and fixation screws. Sense of smell has been notably altered in several patients.

Discussion

Fractures of the anterior skull base present a unique and challenging situation in craniomaxillofacial trauma. The management of these fractures is common, and accepted management techniques for frontal sinus fractures exist but, on occasion, these fractures can be relatively isolated and present a unique challenge in that there is relatively limited frontal sinus involvement. It is in the scenario that the challenge is in the decision as to whether or not to intervene surgically. The author has experienced situations in which there is relatively limited other regional trauma but significant anterior skull base component such as in a small caliber gunshot wounds or even in blunt trauma situations. These are commonly observed by the neurosurgeons but, on occasion, these patients re-present with subacute complications such as CSF leak and meningitis or even brain abscess (all of which have been seen by this author). It is in this

situation that the surgeon must be prepared to have a plan for intervening in a manner that allows us anterior skull base access. This can be either through fracture segments in the frontal bone and anterior table of the frontal sinuses as well as posterior table of the frontal sinus or may require elective osteotomies. The latter includes a frontal bar osteotomy for the subcranial approach but also may be further facilitated by adding a low frontal craniotomy. Such a craniotomy has the advantage of both an increased comfort level for the neurosurgeon but also allows for harvesting of calvarial bone grafts from the posterior table of the craniotomy bone segment. Alternatively, such bone grafts can be harvested from the outer parietal cortex.

A key element to aggressive reconstruction of anterior cranial fossa defects, particularly in the region of the cribriform plate, is injury to the olfactory mechanism. We have noted sense of smell alterations after such surgical intervention and it is unknown whether the degree of injury in this region would have impacted the sense of smell regardless of intervention but this certainly something to be considered in terms of the degree of aggressiveness of the exploration and placement of flaps or grafts into the region of the cribriform plate. When possible, the patient is counseled about this preoperatively and further counseled about it postoperatively.

In summary, fractures of the anterior skull base prevent a wide range of challenges and can be commonly observed but equally often should be addressed surgically. The use of subcranial or anterior approaches appears to lessen cortical edema and other intracranial complications and is recommended whenever possible. The latter can be facilitated by large fracture fragment removal but occasionally requires supraorbital bar osteotomies which are not difficult to perform. The use of pericranial flaps and free bone grafts along with fibrin tissue glues appear to be very effective in obtaining the goal of separation of the anterior cranial fossa from the sinonasal regions.

References

1.Stanley RB, Becker TS: Injuries of the nasal frontal orifices in frontal sinus fractures. Laryngoscope 97:728-731, 1987

2.Rohrich RJ, Hollier LH: Management of frontal sinus fractures. Clin Plast Surg 19:219-232, 1992

3.Donald PJ: Frontal sinus ablation but cranialization. Arch Otolaryng 108:142-146, 1982

4.Stanley RB: Management of severe frontobasilar skull fractures. Otolaryng Clin North Am 24:131-150, 1991

5.Raveh J, Laedrach K, Vuillemin T, et al: Management of combined fronto-orbital/skull base fractures and telecanthus in 355 cases. Arch Otolaryng Head Neck Surg 118:605-614, 1992

6.Gliklich RE, Lazor JB: The subcranial approach to trauma of the anterior cranial base: Preliminary report. J Cranio-Maxillofac Trauma 1:56-62, 1995

7.Brustein F, Cohen S, Hudgins R, et al: Frontal basilar trauma: Classification and treatment. Plast Reconstr Surg 99:1314-1321, 1997

8.Gates T, Frodel JL: Frontobasilar blast injuries: Access and treatment. J Cranio-Maxillofac Trauma 4:32-39, 1998

KEYWORDS

Endoscopic; Orbital surgery; Subperiosteal; Orbital roof

Orbital surgery is traditionally performed through an open approach and often involves bone removal for better visualization. The use of an endoscope obviates the need for bone removal in certain situations, particularly for lesions involving the orbital roof. Transorbital use of the endoscope also provides better visualization when one is working deep within the orbit, for instance, on the deep lateral wall. However, the endoscope can only be situated in the subperiosteal space, thus limiting its utility. In the article, the authors describe their technique for transorbital endoscopic surgery and review the uses and limitations of transorbital endoscopic surgery.

© 2008 Elsevier Inc. All rights reserved.

Endoscopic surgery plays a relatively small role in ophthalmology, chiefly because of the constraints of size and space. However, endoscopes are being used for orbital, oculoplastic, lacrimal, and even intraocular procedures. Endoscopic orbital surgery is performed primarily via sinonasal approaches by ENT surgeons. Transnasal endoscopic approaches are well established for orbital decompression,1 orbital medial wall fracture repair,2 and optic canal decompression.3 The use of a transmaxillary or transnasal endoscopic approach also has been described for the repair of orbital floor fractures.2 The ophthalmologist is familiar with the endoscope, primarily in the context of endoscopic dacryocystorhinostomy4 and endoscopic brow lift.5 Nasal endoscopy also has proven to be useful in the perioperative assessment for lacrimal surgery and probing of the nasolacrimal duct.6,7 Additional applications in oculoplastic surgery include transcanalicular endoscopy8 and endoscopic assistance in facelifts9 and in harvesting fascia lata.10 Intraocular endoscopes are used to perform endoscopic cyclophotocoagulation to reduce intraocular pressure in patients with intractable glaucoma.11 The purpose of this article is to review transorbital endoscopic surgery.

The use of endoscopes in orbital surgery was first described by Norris and Cleasby in 1981.12 The initial reports by Norris detailed the use of the endoscope in biopsying

Address reprint requests and correspondence: Venkatesh C. Prabhakaran, MS, MRCOphth, Prabha Eye Clinic, 504, 40th Cross, Jayanagar, Bangalore-560070, India.

E-mail address: cpvenky@gmail.com.

1043-1810/$ -see front matter © 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.otot.2008.09.004

orbital tumors13 and in removing foreign bodies from the orbit. Isotonic saline was used to provide visualization while the surgeon was dissecting in the orbit. However, its use increased the pressure within the orbit, and the tissues became quickly edematous. Norris and Cleasby also found that that use of air to aid in visualization was not successful.12 Braunstein and coworkers14 have also described the experimental use of flexible endoscopes in the orbits of dogs by using hyaluronate infusion through the endoscope tip to aid visualization. However, the potential for compressive collateral damage during the creation of an optical cavity has limited the use of the endoscope within the orbital fat. Hence, because of the lack of a safely distensible space, intraorbital endoscopy15 is not widely used. In 2004, Selva and Chen16 described the subperiosteal transorbital use of the endoscope during curettage of a cholesterol granuloma of the orbital roof. Since then, there have been reports of

endoscopic approach to lesions of the orbital roof and also on the use of the endoscope as a surgical teaching aid.17,18

Indications

Transorbital endoscopic surgery is only used for procedures involving the orbital bones because the subperiosteal space can be used for situating the endoscope. Lesions such as cholesterol granulomas, orbital dermoids, and Langerhans cell histiocytosis involving the anterior portion of the orbital roof and situated behind the superior orbital rim can be difficult to