视神经鞘减压术的疗效与风险

视神经鞘减压术(ONSD),也称视神经鞘开窗术(ONSF),是一种通过在视神经鞘上开窗以释放视神经周围蛛网膜下液、为视神经减压的外科手术。该手术是为了缓解颅高压所致威胁视力的视乳头水肿(papilledema),常用于药物降颅压无效或不能耐受药物、进行性视力丧失的大脑假瘤综合征(PTCS)患者。本文综述了视神经鞘减压术的适应证、禁忌证、手术方式及其疗效与并发症。     

视神经鞘减压术

视神经鞘减压术是治疗顽固性颅内压增高性视乳头水肿的一种手术治疗手段。主要适应证为:病因不明或病因不能去除,内科治疗不能控制颅内压,而视功能又有进行性损害倾向的颅内压增高性视乳头水肿。本文简要论述了这种术式的历史发展,近年来流行的手术方法、术后效果和并发症,以及对手术原理的推测。     

视神经鞘减压术的术式选择及并发症

视神经鞘减压术（optic nerve sheath fenestration，ONSF）是将眶内段视神经鞘膜开窗来引流脑脊液的手术，主要用于治疗特发性颅内压升高（idiopathic intracranial hypertension，IIH）引起的视功能损伤。此外，它还可以用于治疗其他威胁视功能的疾病。在国外，视神经鞘减压术已经广泛应用，但在国内，绝大多数医院尚未开展该项手术。其手术方式包括眶外侧壁进路、球结膜进路、重睑内侧进路、重睑外侧延长切口进路和鼻内窥镜进路等，常见的并发症有视神经损伤、瞳孔散大、眼球运动障碍、视网膜中央动脉损伤等。     

视神经周围脑膜减压术以解除视乳头水肿

由眼眶内作视神经周围脑膜减压术,在猴实验中治疗视乳头水肿已证明有效,也已应用于病人。本文报告一简易手术方法,并报告7例。 1872年De Wecker已描述用手术治疗视乳头水肿,他从颞下方作结膜切口,触及视神经后用小刀切开鞘膜;他报告二例其视乳头水肿及颅压增高的症状在术后均得到缓解。1887年(?)arter切断外直肌,在直视下钩住视神经鞘膜,再以刀切开之;并报导4例。30年后Müller从侧路开眶,将视神经鞘膜作一三角形切口;并报导19例     

视神经鞘膜减压术治疗多种视神经病变

视神经鞘膜减压术自1872年De Wecker首次提出用于治疗视神经病变以来，引起许多争议。近年来的文献显示其对颅内压增高症引起的原发性视乳头水肿、进行性非动脉炎性前部缺血性视神经病变、急性视网膜坏死综合症等多种视神经病变都具有明显疗效。对视神经鞘膜减压术的发展史、手术技术、作用机理、各种适应证的疗效评价以及可能出现的手术并发症等方面进行系统介绍。 （中华眼底病杂志，1995，11：59-63）     

视神经减压术

当视乳头水肿损害着病人的视力时,现在已渐多地采用“视神经周围脑膜切开减压术”,来争取多保留一点视力。作者报告一例恶性多发性成胶质细胞瘤,双眼慢性视乳头水肿,双侧成功地作了减压手术,术后39天死亡,尸检病理组织切片中,找到手术处硬脑膜有漏孔,他认为此漏孔为主要的减压机制。另有2例慢性视乳头水肿,视力受到损害,各作了一侧视神经减压术,结果使双眼视乳头水肿消退,其临床症状也减轻,推测可能脑脊液也从视神经减压术漏孔处渗出。     

颅内压增高的视神经乳头改变

我们观察了本院1 352例颅内疾患颅内高压后的视神经乳头改变．其中颅内肿瘤934例(包括胶质瘤、脑膜瘤、垂体瘤、神经纤维瘤、颅咽管瘤等)，颅脑外伤360例{均为重型颅脑外伤)，脑血管病58例(动脉瘤及动、静脉畸形破裂出血)．分析了常见颅内疾患颅内高压后视乳头改变的特征、一般规律和诊断要点，并阐述了颅内高压与视乳头水肿之间的关系，提出发现和诊断早期视神经乳头水肿的重要性． （中华眼底病杂志，1994，10：94-96）     

视神经鞘膜切开减压术四例

视神经鞘膜切开减压术四例傅相平，王鸿启，易声禹，顾建文良性颅内压增高导致的慢性视盘水肿，在眼科临床上颇为常见。多数病人治疗预后较好，但有部分病人因病程较长，可发生长期的慢性视盘水肿导致继发性视神经萎缩而失明［１］。早期发现和及时治疗该类病人，是防止视...     

视神经管减压术治疗视神经挫伤三例报告

本文报道 3例由于头颅外伤所致视神经管挫伤而行视神经管减压术 ,手术成功 ,使病人改善恢复视功能和较好的视力 ,报告如下 :例 1:张×× ,男 ,35岁 ,住院号 97712 5 ,患者被汽车撞伤 5天 ,以创伤性湿肺 ,头颅外伤收入脑外科 ,因病人左眼视物不见而请眼科会诊。查视力无光感 ,直接光反射消失 ,间接光反射存在 ,瞳孔散大 7ｍｍ。视神经乳头轻度水肿 ,ＣＴ扫描 ,颅骨骨折 ,蝶骨小翼骨折 ,视神经管狭窄 ,立即转入眼科行视神经管减压术 ,术中将嵌夹在视神经管周围的碎散骨片钳出 ,术后视力恢复到眼前数指 ,2月后视力 0 1,随访 2年视力为 0 2。…     

视神经鞘减压术治疗进行性非动脉炎性缺血性视神经病变

非动脉炎性缺血性视神经病变导致视力轻度到明显下降且发生于老年人。常发生无痛性的视功能损害,瞳孔传入神经受损和视盘水肿。很多病人视力的损害是迅速和持续的。然而在少数病人中大概4％～30％视力丧失可能在六周以内,随后视力自发改善是罕见的。近年来提倡采用视神经鞘减压术治疗进行性非动脉炎性块血性视神经病变,这些治疗效果引起了很多争论。我们治疗了四例病人(五只眼)他们是进行性非动脉炎性缺血性视神经病变,采用了视神经鞘减压术。其中有四只眼视力提高和视野扩大,一只非进行性的眼视力全部丧失。表明手术后没有明显改善。我们的结果证实了以前的发现。视神经鞘减压改善了进行性非动脉炎性缺血性视神经病变所致的视力损害,此症在以前没有成功的治疗。     

Optic nerve sheath fenestration: a revised lateral approach for nerve access

Idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri, describes a disease of poorly understood pathophysiology with a specific set of signs and symptoms including potentially irreversible and blinding visual loss. Optic nerve sheath fenestration (ONSF) is a well-described surgical treatment for patients with IIH and progressive visual loss despite maximally tolerated medical therapy. A number of optic nerve access procedures have been described including medial transconjunctival, superomedial lid crease, and lateral orbitotomy with and without bone takedown. The purpose of this report is to describe a revised lateral approach for temporal optic nerve access that obviates the need to traverse through the intraconal fat of the central surgical space in the previously described lateral approach techniques.     

A 15-year review of secondary and tertiary optic nerve sheath fenestration for idiopathic intracranial hypertension

Purpose: Optic nerve sheath fenestration (ONSF) is a common surgical option for patients with idiopathic intracranial hypertension (IIH) with vision loss refractory to medical management. Little is known about the visual benefit of repeated ONSF. The authors aimed to assess the efficacy of secondary and tertiary ONSF in patients with IIH.

Methods: A retrospective chart review was performed on all patients with repeat ONSF for IIH at Emory University from 1999 to 2016. Primary outcome measures included visual acuity, optic nerve head findings, and visual field results.

Results: A total of nine eyes in seven patients (five females and two males) with repeat ONSF were identified. Two of the seven patients had repeat ONSF in both eyes, while the remaining five patients had only one eye repeated. Five of seven patients (five eyes) improved or remained stable after the secondary ONSF. Two patients (three eyes) continued to worsen despite the secondary fenestration surgery and underwent tertiary ONSF at an average of 13.2 months (SD 5.5 months) after the failed secondary ONSF. Both patients that underwent the tertiary fenestration showed improvement. Six of the patients had either improvement or stability in their clinical findings at their last documented follow-up, but one continued to worsen despite intervention.

Conclusions: This study suggests that secondary and tertiary nerve sheath fenestration is a viable management option for patients with progressive vision loss from IIH. Repeat ONSFs do not appear to have increased complication or failure rates compared to prior documented studies regarding primary fenestrations.     

Controversies: Optic nerve sheath fenestration versus shunt placement for the treatment of idiopathic intracranial hypertension

Background:Idiopathic intracranial hypertension (IIH) has been increasing in prevalence in the past decade, following the obesity epidemic. When medical treatment fails, surgical treatment options must be considered. However, controversy remains as to which surgical procedure is the preferred surgical option – optic nerve sheath fenestration (ONSF) or cerebrospinal fluid (CSF) shunting – for the long-term treatment of this syndrome.Purpose:To provide a clinical update of the pros and cons of ONSF versus shunt placement for the treatment of IIH.Design:This was a retrospective review of the current literature in the English language indexed in PubMed.Methods:The authors conducted a PubMed search using the following terms: Idiopathic IIH, pseudotumor cerebri, ONSF, CSF shunts, vetriculo-peritoneal shunting, and lumbo-peritoneal shunting. The authors included pertinent and significant original articles, review articles, and case reports, which revealed the new aspects and updates in these topics.Results:The treatment of IIH remains controversial and lacks randomized controlled clinical trial data. Treatment of IIH rests with the determination of the severity of IIH-related visual loss and headache.Conclusion:The decision for ONSF versus shunting is somewhat institution and surgeon dependent. ONSF is preferred for patients with visual symptoms whereas shunting is reserved for patients with headache. There are positive and negative aspects of both procedures, and a prospective, randomized, controlled trial is needed (currently underway). This article will hopefully be helpful in allowing the reader to make a more informed decision until that time.     

Complications of Optic Nerve Sheath Fenestration as a Treatment for Idiopathic Intracranial Hypertension

ABSTRACT

There are a number of surgical options for treatment of idiopathic intracranial hypertension (IIH) when it is refractory to medical treatment and weight loss. Optic nerve sheath fenestration (ONSF) is one of these options. Use of this procedure varies among centers due to experience with the procedure and concern for associated complications that can result in severe loss of vision. This review summarizes the literature concerning post-surgical complications of ONSF for IIH.     

Optic nerve sheath decompression for visual loss in intracranial hypertension: report from a tertiary care center in South India

Aim: Severe visual loss is the only serious complication of intracranial hypertension secondary to idiopathic intracranial hypertension (IIH) and some cases of cerebral venous thrombosis (CVT). Optic nerve sheath decompression (ONSD) has been shown to improve or stabilize visual function in patients with IIH, while its role in CVT is yet to be established. We report our experience with optic nerve sheath decompression for visual loss in IIH and CVT. Materials and Methods: In this prospective noncomparative, interventional study, 41 eyes of 21 patients with IIH and CVT and visual loss underwent ONSD. The main outcome measures included best-corrected visual acuity (BCVA), visual fields, pupillary light reflex, optic nerve sheath diameter on B-scan and resolution of papilledema which were evaluated preoperatively and at follow-up at four days, two weeks, one month, three months and final follow-up. In 7/41 eyes with absent light perception preoperatively, the functional outcome was analyzed separately. Results: Following ONSD BCVA and visual fields stabilized or improved in 32/34 (94%) eyes. Statistically significant improvement in BCVA, visual fields and pupillary light reflex occurred over the three month follow-up period. Surgical success was indicated by reduction in optic nerve diameter and papilledema resolution occurred in all patients. The outcome in the IIH and CVT groups was comparable. Four eyes with absent light perception showed marginal improvement in visual acuity. Four eyes had transient benign complications. Conclusion: Optic nerve sheath decompression is an effective and safe procedure to improve or stabilize vision in patients with visual loss caused by IIH and CVT.     

Visual outcomes following optic nerve sheath fenestration via the medial transconjunctival approach

This article determines the safety of optic nerve sheath fenestration (ONSF) for the treatment of patients with intracranial hypertension in the immediate 6-month post-operative period and its efficacy in reducing optic disk edema. Retrospective, non-comparative interventional case series. 207 eyes in 104 patients undergoing ONSF between the years 2005 and 2014. Papilledema grade based on modified Frisen scale and mean deviation of Humphrey visual field. 207 eyes of 104 patients (102 IIH, 2 IH due to dural sinus thrombosis) were included in the study. The patients were 96.1% female (N = 100) and 3.9% male (N = 4). The average patient age was 28.8 years (SD ± 9.5 years) and had a mean opening pressure of 39.85 cmH₂O (SD ± 8.4 cmH₂O). Mean follow-up period was 6.0 months (SD ± 5.9 months). Papilledema resolved in 76.1% of eyes at 1 week (N = 102 eyes), 75% of eyes at 1 month (N = 90 eyes), and 71% of eyes at 6 months (N = 94 eyes). Visual field comparison had a mean of the paired differences in MD at 1 week, 1 month, and 6 months of 1.59dB (P = 0.006), 2.53dB (P < 0.001), and 1.30dB (P = 0.016), respectively. ONSF is effective in reducing optic disk edema and does not cause vision loss in the 6-month post-operative period regardless of severity of IIH (as judged by elevation of opening pressure measured at pre-operative assessment).     

Optic Nerve Sheath Fenestration: A Five Year Audit

Idiopathic intracranial hypertension (IIH), also known as benign intracranial hypertension (BIH) and pseudotumor cerebri, is a syndrome characterised by raised intracranial pressure (ICP) in the absence of an intracranial mass or ventricular abnormality and normal cerebrospinal fluid (CSF). Optic nerve sheath fenestration (ONSF) is advocated as a treatment for patients on maximal medical therapy with progressive visual field loss. We present the visual results of 13 patients undergoing ONSF on 27 eyes (primary, secondary and tertiary procedures) over a 5 year period. Overall 4 eyes (14.8%) had improved visual acuity after surgery, whilst 23 eyes (85.2%) were unchanged. Visual fields were improved in 18 eyes (66.7%), 2 (7.4%) were unchanged and 4 (14.8%) deteriorated despite surgery. Colour vision improved in 12 (44.4%), was unchanged in 3 (11.1%) and deteriorated in 7 (25.9%) eyes. 5 (18.5%) eyes had normal colour vision before and after surgery. 10 (77%) subjects were able to stop medical treatment after ONSF.     

Effect of optic nerve sheath fenestration for idiopathic intracranial hypertension on retinal nerve fiber layer thickness

The objective of the study was to evaluate whether optic nerve sheath fenestration in patients with idiopathic intracranial hypertension was associated with improvement in visual field pattern deviation and optical coherence tomography retinal nerve fiber layer thickness.The records of 13 eyes of 11 patients who underwent optic nerve sheath fenestration were reviewed. The subjects were patients of a clinical practice in Dallas, Texas. Charts were reviewed for pre- and postoperative visual field pattern deviation (PD) and retinal nerve fiber layer thickness (RNFL).PD and RNFL significantly improved after surgery. Average PD preoperatively was 8.51 DB and postoperatively was 4.80 DB (p = 0.0002). Average RNFL preoperatively was 113.63 and postoperatively was 102.70 (p = 0.01). The preoperative PD and RNFL did not correlate strongly.Our results demonstrate that PD and RNFL are improved after optic nerve sheath fenestration. The pre- and postoperative RNFL values were compared to the average RNFL value of healthy optic nerves obtained from the literature. Post-ONSF RNFL values were significantly closer to the normal value than preoperative. RNFL is an objective parameter for monitoring the optic nerve after optic nerve sheath fenestration. This study adds to the evidence that OCT RNFL may be an effective monitoring tool for patients with IIH and that it continues to be a useful parameter after ONSF.     

Resolution of optic nerve edema and improved visual function after optic nerve sheath fenestration in a patient with osteopetrosis

PURPOSE: To describe the outcome of a patient with visual loss and optic nerve edema that resulted from osteopetrosis who underwent an optic nerve sheath fenestration (ONSF). DESIGN: Interventional case report. METHODS: A 33-year-old man with osteopetrosis had bilateral visual field loss and optic nerve edema. Computed tomography and magnetic resonance imaging demonstrated open optic canals. Although a lumbar puncture showed a normal opening pressure, there were other findings that were suggestive of increased intracranial pressure. The patient elected to undergo a unilateral optic nerve sheath fenestration. RESULTS: After ONSF, the patient experienced markedly improved visual acuity, visual field, and optic nerve appearance. CONCLUSION: Individuals with visual loss and optic disk edema that is associated with osteopetrosis may benefit from ONSF if the optic canals appear to be open and the optic nerve edema is thought to be related to increased intracranial pressure.