·Clinical Research·
Newly
onset indirect traumatic optic neuropathy-surgical treatment first versus
steroid treatment first
Bo Yu1,
Ying-Jie Ma2, Yun-Hai Tu1, Wen-Can Wu1
1Department
of Orbital & Oculoplastic Surgery, Eye Hospital of Wenzhou Medical University,
Wenzhou 325000, Zhejiang Province, China
Correspondence to: Wen-Can Wu. Department of Orbital & Oculoplastic
Surgery, Eye Hospital of Wenzhou Medical University, Wenzhou 325000, Zhejiang
Province, China. 172015841@qq.com
Received:
Abstract
AIM: To
investigate the efficacy and safety of the treatment of endoscopic
trans-ethmosphenoid optic canal decompression (ETOCD) with combination of
steroid in patients with newly onset indirect traumatic optic neuropathy (ITON)
and compare the outcome between immediate ETOCD treatment and ETOCD with
preoperative steroid treatment.
METHODS: Patients
presented as newly onset ITON (suffered trauma within 3d) at a tertiary medical
center between Mar 1st, 2016 and Mar 1st, 2018 were
enrolled in this study. All patients were equally and randomly divided into 2
groups. Cases in group A were performed ETOCD immediately after admition while
cases in group B were prescribed by methylprednisolone (20 mg/kg · d) for 3d
before ETOCD. Methylprednisolone (20 mg/kg · d) was used after surgery for 6d
in group A and 3d in group B. Follow-up was up to 3mo in all cases. Visual
acuity (VA) before and after treatment between the two groups were taken into
comparison.
RESULTS: Complete
postoperative data were acquired from 34 patients in group A and from 32
patients in group B. Group A had significantly higher effective rate in VA than
group B (χ2
=4.905, P=0.027).
CONCLUSION: For
patients with newly onset ITON, combination treatment of ETOCD with high-dose
steroid is an effective and safe way. Immediate surgery will lead to better
prognosis for these cases.
KEYWORDS: indirect
traumatic optic neuropathy; endoscopic trans-ethmosphenoid optic canal
decompression; steroid; visual acuity; newly onset
DOI:10.18240/ijo.2020.01.18
Citation: Yu B, Ma YJ, Tu YH, Wu WC. Newly onset indirect traumatic optic
neuropathy-surgical treatment first versus steroid treatment first. Int J
Ophthalmol 2020;13(1):124-128
INTRODUCTION
Traumatic optic neuropathy (TON) is a rare and
potentially vision-threatening condition caused by ocular or head trauma with
the incidence rate of 0.5%-5%[1-3].
TON may result from either direct or indirect injury.
Direct optic nerve injury is usually caused by optic nerve laceration or
avulsion, or by direct fracture of the optic canal. Thus, it could always lead
to poor prognosis. Indirect optic injury is usually due to increased
intracanalicular pressure after an injury. A secondary disorders would happen
due to the a cascade of molecular and chemical mediators, initiated by this
increased intracanalicular pressure[4]. Therefore, indirect injuries
may derive benefit from treatment[4-5].
Time between the trauma and first treatment is
considered as a strong predictor of indirect traumatic optic neuropathy (ITON).
Early treatment always leads to better prognosis[6-7].
The treatment of ITON, especially for newly on-set
cases, is still controversial. High-dose steroid is recommended as the primary
treatment for ITON by previous studies[8-9]. Endoscopic
trans-ethmosphenoid optic canal decompression (ETOCD) was brought out by some
ENTs as a new therapy for ITON[10]. Treatment of ETOCD with
combination of steroid was then used as another treatment of ITON which was
considered as a more effective way of treating ITON[1,6,11].
However, when to perform ETOCD, immediate after admition or after several days
steroid treatment, hasn’t reached agreement. Yang et al[12]
suggested that high dose intravenous steroid therapy should be the primary
treatment for ITON, and ETOCD can be performed as an adjuvant to steroid
therapy in cases where steroids failed. However, Song et al[13]
found that no differences in the outcomes between cases who received surgery
with pre-operative steroid therapy and those underwent surgery alone. He
believed that it was not necessary to wait for the effect of steroid before
surgery[13].
Our study aimed to investigate the efficacy and
safety of the treatment of ETOCD with combination of steroid in patients with
newly on-set ITON and compare the outcome between immediate ETOCD treatment and
ETOCD with preoperative steroid treatment.
SUBJECTS AND METHODS
Ethical Approval
The study was approved
by the local Ethical Research Committee (KYK[2016]18) and was authorized by the
Eye Hospital of
All patients in this series had loss of vision after
trauma with an afferent pupillary defect in the involved eye. High resolution
brain and orbital computed tomography scans were performed in all patients.
Optical coherence tomography scan and fundus photo were performed as well.
Patients with bilateral ITON were excluded in our
study. Patients had previous treatment or with a history of consciousness
impairment were also excluded in our study. Cases who refused surgery were
excluded in this study as well. Then the rest patients were randomly equally
divided into 2 groups, group A and group B. Cases in group A were performed
ETOCD immediately after admition while cases in group B were prescribed by
methylprednisolone (20 mg/kg·d) for 3d before ETOCD. Methylprednisolone (20
mg/kg·d) was used after surgery for 6d in group A and 3d in group B. Patients
were followed up to 3mo after surgery. Written content was signed by all cases
before surgery. We recorded the demographic characteristics of the patients,
including visual acuity (VA) before and 3mo after surgery, time to medical
treatment, other accompanied conditions, including hemorrhage within sphenoid
sinus and/or the post-ethmoid, optic canal fracture and orbital fracture. VA
improvement is defined as 1) VA improved ≥2 lines on the Snellen visual chart;
2) VA improved from no light perception (NLP) to light perception (LP) or
better; 3) VA improved from LP to hand motion (HM) or better; 4) VA improved
from HM to finger counting (FC) or better; 5) VA improved from FC to 0.01 or
better[5-6].
Surgical Procedure All of the procedures were performed by the same surgeon
(Wu WC). The surgical procedure was detailed describe in our previous studies[2,11].
During the surgery, a routine endoscopic sphenoethmoidectomy was performed
using the Messerklinger technique. After sphenoethmoidectomy and optic nerve
canal locating, the optic canal was thinned with a microdrill and removed with
a microcurrette. Then, the periorbita of the orbital apex, annulus of Zinn and
the optic nerve sheath were incised with a sharp 9# microvitreoretinal (MVR) knife. Finally, a piece of sterile gelatine sponge
that was immersed in mouse-derived nerve growth factor (30 mg/mL; Staidson,
Biopharmaceuticals Co.,
Figure 1 The surgical procedures of endoscopic
trans-ETOCD A: A microdrill was used to thin the
middle wall of optic canal; B: The thinned medial wall was removed by a
microcurrette; C: A sharp 9# MVR knife was used to incised the optic nerve
sheath; D: The opened sphenoid sinus was covered by a piece of sponge that was
immersed in mouse-derived neuron growth factor and dexamethasone.
Statistical Analysis Statistical analyses were performed with SPSS version
RESULTS
Totally, 82 cases were enrolled in this study (41
cases in each group). Of 34 cases in group A finished the follow-up while 32
cases in group B finished the follow-up. The clinical characteristic of them
were list in Table 1.
Table 1 Clinical characteristics of patients
n (%)
|
Characteristics |
Case in group A |
Case in group B |
|
Injury type |
|
|
|
Fall |
6 (17.6) |
12 (37.5) |
|
Car
accident |
19 (55.9) |
12 (37.5) |
|
Assault |
9 (26.5) |
6 (18.75) |
|
Explode |
0 (0） |
2 (6.25) |
|
Age, y |
33.74±11.53 |
32.72±9.80 |
|
Orbital bone fracture |
|
|
|
Yes |
15 (44.1) |
11 (34.4) |
|
No |
19 (55.9) |
21 (65.6) |
|
Hemorrhage within the sphenoid sinus and/or post-ethmoid |
|
|
|
Yes |
13 (38.2) |
15(46.9) |
|
No |
21 (61.8) |
17(53.1) |
|
Optic canal fracture |
|
|
|
Yes |
20 (58.8) |
21(65.6) |
|
No |
14 (41.2) |
11(34.4) |
|
The time to medical treatment |
|
|
|
Within 1d |
11 (32.3) |
9 (28.1) |
|
1 to 2d |
15 (44.1) |
13 (40.6) |
|
2 to 3d |
8 (23.5) |
10 (31.3) |
|
VA before surgery |
|
|
|
NLP |
20 (58.8) |
21 (65.6) |
|
Non-NLP |
14 (41.2) |
11 (34.4) |
VA: Visual acuity; NLP: No light perception; Non-NLP:
Visual acuity better than no light perception.
There were no statistically significant differences
in patients age (t=0.396, P=0.693), NLP rate before treatment (χ2=0.324,
P=0.569), the rate of hemorrhage within the post-ethmoid and/or sphenoid
sinus (χ2=0.504, P=0.478), orbital fracture (χ2=0.655,
P=0.418) and OCF (χ2=0.324, P=0.569) between
group A and group B.
VA in 25 out of 34 patients in group A was improved,
with an effective rate of 73.5%. These patients had pre-treatment NLP in 20
eyes, LP in 5 eyes, HM in 2 eyes, FC in 2 eyes and better than FC in 5 eyes.
Twelve of 20 cases with NLP pre-treatment had improved post-treatment vision,
including LP in 3 eyes, HM in 1 eye, FC in 3 eyes and better than FC in 5 eyes.
All 5 patients with LP pre-treatment had improved in vision after treatment,
including HM in 2 eyes and better than FC in 3 eyes. Both 2 cases with HM
before treatment had improved to FC in vision after treatment. Both 2 cases
with FC pre-treatment had improved to 20/200 after treatment. Four of 5 cases
with better than FC pre-treatment had improved in vision after treatment,
including 1 from 20/200 to 20/60, 1 from 20/200 to 20/50, 1 from 20/100 to 20/20
and 1 from 20/40 to 20/20 (Table 2).
Table 2 The VA before and after treatment of cases in
group A
|
VA pre-treatment (n) |
VA post-treatment |
||||
|
NLP |
LP |
HM |
FC |
Better than FC |
|
|
NLP (20) |
8 |
3 |
1 |
3 |
5 |
|
LP (5) |
0 |
0 |
2 |
0 |
3 |
|
HM (2) |
0 |
0 |
0 |
2 |
0 |
|
FC (2) |
0 |
0 |
0 |
0 |
2 |
|
Better than FC (5) |
0 |
0 |
0 |
0 |
|
VA: Visual acuity; NLP: No light perception; LP:
Light perception; HM: Hand motion; FC: Finger count. aFour of 5 cases with better than FC pre-treatment had
improved in vision after treatment, including 1 from 20/200 to 20/60, 1 from
20/200 to 20/50, 1 from 20/100 to 20/20 and 1 from 20/40 to 20/20.
VA was improved in 15 out of 32 patients in group B,
with an effective rate of 46.9%. These patients had pre-treatment NLP in 21
eyes, LP in 1 eye, HM in 3 eyes, FC in 5 eyes and better than FC in 2 eyes.
Nine of 21 cases with NLP pre-treatment had improved in vision after treatment,
including LP in 1 eyes, HM in 1 eye, FC in 5 eyes and better than FC in 2 eyes.
Patient with LP pre-treatment had improved to FC vision after treatment. Two of
3 cases with HM before treatment had improved in vision after treatment,
including FC in 1 eye and 20/
Table 3 The VA before and after treatment of cases in
group B
|
VA pre-treatment (n) |
VA post-treatment |
||||
|
NLP |
LP |
HM |
FC |
Better than FC |
|
|
NLP (21) |
12 |
1 |
1 |
5 |
2 |
|
LP (1) |
0 |
0 |
0 |
1 |
0 |
|
HM (3) |
0 |
0 |
1 |
1 |
1 |
|
FC (5) |
0 |
0 |
0 |
3 |
2 |
|
Better than FC (2) |
0 |
0 |
0 |
0 |
|
VA: Visual acuity; NLP: No light perception; LP:
Light perception; HM: Hand motion; FC: Finger count. aOne cases with better than FC pre-treatment had
improved in vision , who improved from 20/40 to 20/25.
During the surgery, cerebrospinal fluid rhinorrhea
was happened in 4 patients. All of them were repaired by mucosal flap
transplantation uneventfully during surgery and totally recovered from strict
bed rest in a 30 degree of head-up position for a week. No other severe
complications were observed.
DISCUSSION
ITON is a serious complication of head trauma which
could have serious outcomes. Most of patients suffer ITON in their early
Indirect optic nerve injury is caused by increased
intracanalicular pressure after injury[4-5]. Though this disease has
been known for over for many years, the precise pathogenesis of ITON is still
unclear. However, various studies trying to explain the mechanism of optic
nerve damaging in ITON were conducted. Some studies suggested that when forces
applied to the frontal bone, it would be transferred and concentrated in the
optic canal region. It would result in optic nerve damaging[15].
Others demonstrated that patients with indirect injury to optic nerve had been
consistent with localization of the lesion to this area which may cause damaging
in optic nerve[16]. Increased intracanalicular pressure after injury
may initiate a cascade of molecular and chemical mediators. A secondary
disorders such as intraneural oedema, haematoma, altered microvasculature or
cerebrospinal fluid circulation, and interruption of direct axoplasmic
transport, would happen due to the a cascade of molecular and chemical
mediators, initiated by this increased intracanalicular pressure[4].
Treatment for ITON remains controversy. Although
observation alone showed improvement in VA in some cases[17-18],
most ophthalmologists do not think it is enough for ITON especially for newly
on-set ones. High-dose steroid is recommended as the primary treatment for ITON
by previous studies[8-9]. Optic canal decompression (OCD) was raised
up these years by some authors. OCD physically decompresses the optic nerve
within the canal, which could create space for the nerve to swell, thus to
decrease the damaging effect[13]. Different approaches have been
advocated for OCD, including transcranial, transantral, intranasal microscopic
and endoscopic approaches[10,13,19-21]. There are many advantages
with endoscopic approach, such as less morbidity, good cosmetic results without
external scarring, preservation of olfaction, and a shorter recovery time. In
addition, the endoscopic approach provides an excellent view of the orbital
apex[22]. Thus, endoscopic approach of OCD was chosen in our study.
Treatment of OCD with combination of steroid and
surgery was found to be more effective than steroid only. According to previous
researches, the VA improvement rate of high-dose steroid treatment alone was
4.3%-44%, and high-dose steroid combined with OCD was 60.9%-71.1%[11,22-23].
According to the retrospective study we made before, the effective rate of
combination treatment was higher than it of using steroid only[11].
Therefore, this combination therapy was used in our study as well.
When to perform ETOCD is still controversial. Song et
al’s[13] believed that it was not necessary to wait the effect
of steroid before surgery[13]. We found that cases who received
immediate ETOCD had better prognosis than those underwent steroid therapy
before ETOCD. This may because that ETOCD has better effect of OCD than
steroid. We found the subsiding of optic nerve edema at the second day after
ETOCD while it remained the same at the second day after steroid treatment.
What’s more, ETOCD can relieve the compression of optic nerve caused by optic
canal fracture.
Whether to split the nerve sheath is another controversial
issue[23]. Thakar et al[24] believed that the
annulus of Zinn at the anterior end of the fibrous sheath may related to edema.
However, sheath splitting could increase the risk of cerebrospinal fluid
leakage, the happening of ophthalmic artery injury and injury to the optic
nerve. In order to improve the effectiveness and safety of surgery, several
modified surgical methods were made in our surgical procedure: 1) Punctuated
optic nerve sheath splitting was made in this study. This procedure is different
from the traditional way, which is associated with complications like
cerebrospinal fluid leakage, ophthalmic artery injury and optic nerve injury.
In our surgery, 5 to 6 small punctuated incision about
For patients with newly on-set ITON, combination
treatment of ETOCD with high-dose steroid is an effect and safety way.
Immediate surgery will lead to better prognosis for these cases.
ACKNOWLEDGEMENTS
Foundations: Supported by the Natural Science Foundation of
Conflicts of Interest: Yu B, None; Ma YJ, None; Tu YH, None; Wu
WC, None.
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