We treated 40 affected eyes of 40 patients with traumatic optic neuropathy with optic nerve decompression, high-dose corticosteroids and non-specific therapy, respectively, and the preliminary results are summarized and analyzed as follows.
Subjects and methods
Forty consecutive cases with 40 eyes were treated in our hospital from February 1995 to November 1997 in both outpatient and inpatient settings. All cases had a history of closed head trauma and were associated with severe post-injury visual impairment. Among them, 26 eyes had no light perception after the injury; 7 eyes had visual acuity for a short period of time after the injury and then black eye blindness occurred; 1 eye had visual acuity of 0.01 after the injury; 6 eyes had visual acuity naturally recovered to light perception ~ number of fingers within 2 weeks after the injury. All eyes had afferent pupillary reflex disorder, and there were no significant changes of the optic disc and retina in the fundus within 2 weeks after the injury, while optic nerve atrophy occurred in the distant stage. There were 37 cases (92.5%) with bone damage and other abnormalities on imaging examination, and 3 cases (7.5%) without bone damage. Based on the above medical history, symptoms and signs, all 40 patients were consistent with the diagnosis of posterior traumatic optic neuropathy. The hospitalized patients were randomly divided into surgical treatment group and corticosteroid treatment group. Those who had lost the timing of surgery and corticosteroid treatment more than 1 month after the injury, but whose diagnosis and condition were eligible for enrollment, filled in the registration form item by item as the control group of non-special therapy treatment.
1, observation subjects grouping
Surgical treatment group: 14 patients, all of whom underwent optic nerve decompression. Among them, 6 cases were treated by transcranial route, 4 cases by orbital sieve route and 4 cases by sinus endoscopic route.
High-dose corticosteroid treatment group: 11 patients, initially 5 were treated with dexamethasone, the treatment regimen was 1 mg/(kg*d) in 2 intravenous drips for 3 d. The dose was gradually reduced from 7.5 mg orally on the 4th day for 14 d. After that, 6 patients were treated with methylprednisolone, the treatment regimen was 30 mg/kg intravenously for the first time for 8 h for those who started treatment within 3 d after injury, and then 5.4 mg/(kg*h) intravenously for 23 h and 250 mg/6 h intravenously for 24-48 h. For those who started treatment more than 3 d after injury, methylprednisolone was given at the first dose of 1000 mg intravenously, followed by 500 mg intravenously twice/d for 2 d. Prednisone 50 mg/d was given orally from the 3rd d onwards and gradually reduced to 14 d. For those who started treatment more than 3 d after injury, methylprednisolone was given at the first dose of 1000 mg intravenously, followed by 500 mg intravenously for 2 d. Prednisolone 50 mg/d was given orally from the 3rd d onwards and gradually reduced to 14 d.
Non-specific therapy group: 15 patients, same as the above 2 groups, received general treatment such as dehydrating drugs, antibiotics, energy combination, and vitamins after craniocerebral trauma.
Follow-up
All cases were followed up by outpatient clinic (at least 2 times) for more than 3 months and by telephone.
Judgment of efficacy
No change: no change in visual acuity before and after treatment; recently effective: visual acuity improved within 3 d of treatment; distantly effective: visual acuity improved at the last follow-up compared with post-injury visual acuity.
Statistical methods
The χ2 test and Fisher’s exact probability test were analyzed by SAS software, and logistic analysis was performed to evaluate the role of confounding factors affecting the final visual acuity results.
2. Results
Visual acuity
In the high-dose corticosteroid treatment group, the difference between 5 cases treated with dexamethasone (final visual acuity improved in 4 cases and no change in 1 case) and 6 cases treated with methylprednisolone (final visual acuity improved in 4 cases and no change in 2 cases) was not significant by χ2 test (P=0.89). Because of the small number of cases, they were combined into one group and compared with the surgical treatment group and the non-specific therapy treatment group, and the final visual acuity of the surgical treatment group improved in 5 cases and did not change in 9 cases (Table 1). The final visual acuity in the high-dose corticosteroid treatment group was significantly better than that in the surgical treatment group (Fisher test, χ2=7.82, P=0.005) and better than that in the non-specific treatment group (final visual acuity improved in 7 cases and remained unchanged in 8 cases) (Fisher test, χ2=5.18, P=0.023).
Comparison of the high-dose corticosteroid treatment group with the surgical treatment group
To exclude the effect of confounding factors by natural recovery, the treatment results of the high-dose corticosteroid treatment group and the surgical treatment group were further evaluated by the recent efficiency rate. For those with significant visual acuity improvement within 3 d after treatment, 2 eyes in the surgical treatment group and 5 eyes in the high-dose corticosteroid treatment group; for those with no change in visual acuity within 3 d, 9 eyes in the surgical treatment group and 2 eyes in the high-dose corticosteroid treatment group. The recent efficiency was higher in the high-dose corticosteroid treatment group than in the surgical treatment group (Frisher test, χ2=5.1034, P=0.024).
Factors influencing prognosis
Based on the final visual outcome of having light perception at the last follow-up, the effects of treatment modality, age, mechanism of injury, post-injury state of consciousness, direct site of injury, and the occurrence of optic nerve canal fracture on the final visual outcome were analyzed, and their logistic regression analysis is shown in Table 2, in which treatment modality and absence of light perception after injury (P=0.034) were the factors that had significant effects on final visual acuity. The non-specific therapy treatment group was used as a reference for treatment modality, P=0.28 for the surgical treatment group, and P=0.0125 for the high-dose corticosteroid treatment group. because the post-injury visual acuity was better in the non-specific therapy treatment group than in the surgical treatment group, the results were masked by bias and need to be corrected by further expansion of the sample.
Discussion
The percentage of cases in this group with complete final vision loss was 47.5%, which is similar to the percentage of complete vision loss reported in the literature [1-3]. High doses (30 mg/kg) of methylprednisolone are thought to exert a therapeutic effect on CNS damage by effectively inhibiting lipid peroxidation [4]. The results of a multicenter, double-blind, placebo-controlled study have affirmed the therapeutic efficacy of methylprednisolone in acute spinal cord injury [5].The Boston Conference on Extracranial Optic Nerve Decompression (1995) developed a multicenter randomized controlled study program [6], but this study has not been reported to date.
Preliminary analysis of the results of this study showed that those treated with high-dose corticosteroids had better outcomes than those treated with surgery and non-specific therapies. Although the cases in this group were randomly selected, the sample was small, and more patients in the non-specific therapy group had post-injury visual acuity above light perception than those in the surgical treatment group (P=0.08), so it was not yet possible to compare the two groups, and further comparisons need to be made with an expanded sample. All 14 patients in the surgical treatment group had no light perception after the injury, and the surgical efficiency was 35.71%, which was similar to the efficiency reported in the literature [2-7], although the results with the non-specific therapy treatment group are yet to be determined, but significantly less than the high-dose corticosteroid treatment group (P<0.05). Recent efficiency analysis further confirmed the higher recent efficiency in the high-dose corticosteroid treatment group than in the surgical treatment group (P=0.002). Multivariate analysis was used to screen the risk factors associated with visual prognosis and the advantages of the different treatments, and the results confirmed that the absence of light perception after injury was a risk factor for poor visual prognosis and also reflected the superiority of high-dose corticosteroid treatment among the three different therapies.