Surgery for Optic Nerve Injury: Should Nerve Sheath Incision Supplement Osseous Decompression?

ABSTRACT

Objective: To evaluate the benefits and risks of performing an optic nerve sheath incision to supplement standard osseous optic canal decompression for traumatic optic neuropathy. Methods: Before-after analysis of 57 cases undergoing optic nerve decompression at a tertiary referral centre from 1988–2006. Fifty-five cases had adequate post surgical follow-up for evaluation for improvement. Group A (n = 35) had decompression of the osseous optic canal and surgical slitting of the optic nerve sheath; Group B (n = 22) had osseous decompression alone. The groups were comparable for age, injury severity, and injury-surgery interval. Main outcome measure: Percentage visual improvement, which was calculated by conversion of the pre- and post-intervention visual acuity measurements to the logarithm of the minimum angle of resolution (logMAR) scale. Results: No significant recovery was noted in subjects with persistent complete blindness (PL-ve vision). In subjects with residual pre-op vision, the quantum of recovery was greater in Group A than in Group B (46% and 33% respectively, p = 0.10). The difference was especially evident in subjects with no optic canal/posterior orbit fracture (p = 0.07). Three cases with the sheath incision developed transient CSF rhinorrhea in the initial experience, but this was subsequently alleviated with modification of surgical technique. Conclusion: The addition of optic nerve sheath incision to osseous decompression may improve recovery in optic nerve injury, especially in subjects without optic canal fracture.

KEYWORDS

Optic nerve injury - optic nerve decompression - optic nerve sheath - endoscopic skull base

REFERENCES

• 1 Cook M W, Levin L A, Joseph M P, Pinczower E F. Traumatic optic neuropathy. A meta-analysis.  Arch Otolaryngol Head Neck Surg. 1996;  122 389-392
• 2 Levin L A, Beck R W, Joseph M P, Seiff S, Kraker R. The treatment of traumatic optic neuropathy: the International Optic Nerve Trauma Study.  Ophthalmology. 1999;  106 1268-1277
• 3 Tandon D A, Thakar A, Mahapatra A K, Ghosh P. Trans-ethmoidal optic nerve decompression.  Clin Otolaryngol. 1994;  19 98-104
• 4 Walsh F B. Pathological–clinical correlations. I. Indirect trauma to the optic nerves and chiasm. II. Certain cerebral involvements associated with defective blood supply.  Invest Ophthalmol. 1966;  5 433-449
• 5 Steinsapir K D, Goldberg R A. Traumatic optic neuropathy.  Surv Ophthalmol. 1994;  38 487-518
• 6 Chen Y R, Breidahl A, Chang C N. Optic nerve decompression in fibrous dysplasia: indications, efficacy and safety.  Plast Reconstr Surg. 1997;  99 22-30
• 7 Thakar A, Mahapatra A K, Tandon D A. Delayed optic nerve decompression for indirect optic nerve injury.  Laryngoscope. 2003;  113 112-119
• 8 Luxenberger W, Stammberger H, Jebeles J A, Walch C. Endoscopic optic nerve decompression: the Graz experience.  Laryngoscope. 1998;  108 873-882
• 9 Onofrey C B, Tse D T, Johnson T E et al.. Optic canal decompression: a cadaveric study of the effects of surgery.  Ophthal Plast Reconstr Surg. 2007;  23 261-266
• 10 Niho S, Niho M, Niho K. Decompression of the optic canal by the transethmoidal route and decompression of the superior orbital fissure.  Can J Ophthalmol. 1970;  5 22-40
• 11 Fukado Y. Results in 400 cases of surgical decompression of the optic nerve.  Mod Probl Ophthalmol. 1975;  14 474-481
• 12 Sofferman R A. The recovery potential of the optic nerve.  Laryngoscope. 1995;  105(supplement 72) 1-38
• 13 Matsuzaki H, Kunita M, Kawai K. Optic nerve damage in head trauma: clinical and experimental studies.  Jpn J Ophthalmol. 1982;  26 447-461
• 14 Kountakis S E, Maillard A A, Urso R, Stiernberg C M. Endoscopic approach to traumatic visual loss.  Otolaryngol Head Neck Surg. 1997;  116 652-656
• 15 Fujitani T, Inoue K, Takahashi T, Ikushima K, Asai T. Indirect traumatic optic nerve neuropathy- visual outcome of operative and nonoperative cases.  Jpn J Ophthalmol. 1986;  30 125-134
• 16 Girard B C, Bouzas E A, Lamas G, Soudant J. Visual improvement after transethmoid-sphenoid decompression in optic nerve injuries.  J Clin Neuroophthalmol. 1992;  12 142-148
• 17 Mine S, Yamakami I, Yamaura A et al.. Outcome of traumatic optic neuropathy. Comparison between surgical and nonsurgical treatment.  Acta Neurochir (Wien). 1999;  141 27-30
• 18 Chen C T, Huang F, Tsay P K et al.. Endoscopically assisted transconjunctival decompression of traumatic optic neuropathy.  J Craniofac Surg. 2007;  18 19-26
• 19 Levin L A, Joseph M P, Rizzo III J F, Lessell S. Optic canal decompression in indirect optic nerve trauma.  Ophthalmology. 1994;  101 566-569
• 20 Wang B H, Robertson B C, Girotto J A et al.. Traumatic optic neuropathy: a review of 61 patients.  Plast Reconstr Surg. 2001;  107 1655-1664
• 21 Rajiniganth M G, Gupta A K, Gupta A, Bapuraj J R. Traumatic optic neuropathy: visual outcome following combined therapy protocol.  Arch Otolaryngol Head Neck Surg. 2003;  129 1203-1206
• 22 Lang J. Anatomy of optic nerve decompression, in surgical anatomy of the skull base. In: Samii M, Draf W Surgery of the Skull Base, an Interdisciplinary Approach. Berlin; Springer 1989: 16-18
• 23 Joseph M P, Lessel S, Rizzo J, Momose J. Extracranial optic nerve decompression for traumatic optic neuropathy.  Arch Ophthalmol. 1990;  108 1091-1093
• 24 Wohlrab T M, Maas S, de Carpentier J P. Surgical decompression in traumatic optic neuropathy.  Acta Ophthalmol Scand. 2002;  80 287-293