Medial Transconjunctival Research Articles

Optic Nerve Sheath Fenestration: A Retrospective Review of Its Safety, Efficacy, and Impact on Optical Coherence Tomography.

This study aimed to evaluate the safety and efficacy of optic nerve sheath fenestration using visual acuity, perimetry, and optical coherence tomography. A retrospective review of patients who underwent an optic nerve sheath fenestration at an academic center between 2016 and 2021 was performed with institutional review board approval. Outcome measures included visual acuity, perimetric mean deviation, optic disc edema grade, improvement in symptoms, and intraoperative and postoperative complications. Optical coherence tomography data collected included macular ganglion cell volume and thickness, as well as retinal nerve fiber layer thickness. Preoperative baseline data and 1-, 6-, and 12-month postoperative data were collected. Repeated measures with a mixed-effects model were used for continuous data, and linear regression analyses were performed. A total of 55 patients (86 eyes) underwent optic nerve sheath fenestration, via a medial transconjunctival approach by the same orbital surgeon. After 12-month follow-up, visual acuity (P < 0.05), perimetric mean deviation (P < 0.05), and optic disc edema (P < 0.001) improved in the operative eye. Retinal nerve fiber layer thickness decreased from a mean of 165 to 92 µm (P < 0.001). Macular ganglion cell volume was found to have a small decrease from baseline and correlated well with visual acuity, contrast sensitivity testing, and perimetric mean deviation (P < 0.001). Optic nerve sheath fenestration performed via a medial transconjunctival approach is a safe and effective method to preserve vision in patients with papilledema, particularly in cases of fulminant or progressive idiopathic intracranial hypertension. Quantitative measurements of the macular ganglion cell layer can serve as a useful adjunct to other diagnostic testing.

Optic nerve sheath fenestration: Current status in France and comparison of 6 different surgical approaches

Optic nerve sheath fenestration (ONSF) is a surgical procedure commonly performed in the Anglo-Saxon countries for the treatment of medically refractory idiopathic intracranial hypertension (IIH). We chose to compare 6 different trans-orbital surgical approaches to ONSF. We also desired to determine the number of optic nerve decompression procedures performed in France in 2019 and 2020. Four fresh frozen orbits were dissected at the University of Nice anatomy laboratory. We performed the following surgical approaches: (i) eyelid crease, (ii) lid-split, (iii) medial transconjunctival with medial rectus disinsertion, (iv) medial transconjunctival without rectus disinsertion, (v) lateral transconjunctival and (vi) lateral orbitotomy. For each surgical approach, we measured the distance between the incision and the optic nerve dura mater. We also extracted data from the French National PMSI (Programme de Médicalisation des Systèmes d' Information) database from January 2019 through December 2020 to determine the annual number of optic nerve decompression procedures. The lid crease and medial transconjunctival approaches provided the shortest distance to the optic nerve (average 21mm and 24mm, respectively) and the lowest levels of difficulty compared to the other surgical routes. A total of 23 and 45 optic nerve decompressions were performed in France in 2019 and 2020, respectively. Among them, only 2 and 7 procedures, respectively, were performed through a trans-orbital approach. Upper lid crease incision and medial transconjunctival approaches are the most direct and easiest surgical routes when performing an ONSF. We found that ONSF was rarely performed in France. We strongly recommend close cooperation between ophthalmologists, neurologists, neurosurgeons and interventional radiologists.

A technique for excisional optic nerve biopsy

ABSTRACT Purpose To describe a transconjunctival technique for full-thickness (excisional) optic nerve biopsy. Method A medial transconjunctival approach to the optic nerve with disinsertion of the medial rectus is used. A small right-angle Mixter forcep is used to clamp the optic nerve far posteriorly, and then a microscalpel is directed metal-on-metal to cut the posterior optic nerve. The cut nerve is then rotated anteriorly to complete the proximal nerve cut. Result A full-thickness specimen of 11 mm of more can be obtained without undue traction on the globe. The globe remains viable. Conclusion A long length, excisional optic nerve biopsy can be readily and safely performed without endoscopic techniques.

Navigated Transconjunctival Endoscopic Approaches to the Orbit

ABSTRACT BACKGROUND Standard cranial approaches to the orbit involve lengthy skin incisions, extensive soft tissue dissection, and large craniotomies, increasing morbidity. OBJECTIVE To evaluate less invasive approaches to the orbit, using endoscopic transconjunctival approaches. METHODS Neuronavigated transconjunctival approaches to the orbit were performed on 4 cadavers using 30°/3 mm and 0°/6 mm rigid endoscopes. A special head frame was designed for this study to prevent excessive movement of the endoscope tip in the orbit. Lateral and medial transconjunctival supra- and infrabulbar approaches to the extra- and intraconal spaces were performed. The incision length, maximal penetration depth in the extra- and intraconal spaces, and distance from the orbital rim to the optic nerve were measured. RESULTS All 4 approaches afforded satisfactory exposure and access to the extra- and intraconal spaces. The mean incision length for the transconjunctival approach was 10.4 mm. The optic nerve could be exposed through all 4 approaches. The mean maximal penetration depths in the extraconal space were 28.6 ± 3.5 mm for the 30°/3 mm and 20.7 ± 4.5 mm for the 0°/6 mm endoscope. In the intraconal space, the mean maximal depth of penetration was 23.8 ± 2.4 mm for the 30°/3 mm and 19.4 ± 3.4 mm for the 0°/6 mm endoscope. Based on these measurements, the orbit was classified into quadrants and zones. CONCLUSION Transconjunctival endoscopic approaches to the orbit allow maximal exposure of the extra- and intraconal spaces through a minimally invasive approach requiring no muscle transection. Infrabulbar approaches have better cosmetic results than suprabulbar approaches, which require incision of the eyelid.

Optic nerve sheath fenestration via a supero-medial eyelid skin crease approach for the treatment of idiopathic intracranial hypertension in a UK population.

Optic nerve sheath fenestration (ONSF) is a surgical intervention in the management of idiopathic intracranial hypertension (IIH) infrequently performed in the United Kingdom. Numerous surgical approaches have been described, including medial transconjunctival, lateral and endoscopic. We describe our outcomes and complications from ONSF via a supero-medial eyelid skin crease incision in patients with IIH. We performed a retrospective review of consecutive patients undergoing ONSF for IIH between January 2011 and December 2017 by a single surgeon. Thirty patients were included in the analysis with a median follow-up of 14.5 months. Bilateral ONSFs were undertaken in 27 (90%). The data from one eye per patient were analysed. The mean kinetic perimetry score in mean radial degrees of the I4e isopter improved from 27.3° to 35.7°, p = 0.04. After removing cases with optic atrophy, the median modified Frisén grade of papilloedema improved from 2.5 to 1.0, p = 0.007. A total of 5/30 (17%) patients had complications: two (7%) had recurrence/late failure (one managed medically and one with cerebrospinal fluid [CSF] diversion surgery), one had transient cotton wool spots post-operatively, one had transient retinal haemorrhages and one patient had a transiently oval pupil. No patients had repeat ONSF, but CSF diversion surgery was subsequently carried out in 4/30 (13%) patients. ONSF via a supero-medial eyelid skin crease approach is effective at improving visual function in patients with IIH. The complication rates are low when compared with CSF diversion surgery and other surgical approaches for ONSF.

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

ABSTRACTIdiopathic 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.

Benefits of the Retrocaruncular Approach to the Medial Orbit

Current trends in the management of medial orbital wall fractures are toward the development of transconjunctival incisions and the use of endoscopic-assisted methods. Different authors have suggested variations of the medial transconjunctival approach. (1) In 30 fresh cadaver orbits, the classic transcaruncular approach was compared with the precaruncular and retrocaruncular approach under magnified dissection. (2) A retrospective analysis was conducted on a series of 20 consecutive patients that underwent primary repair of medial orbital wall fractures using a retrocaruncular approach without endoscopic assistance. Postoperative computed tomography scans were obtained for all patients and were evaluated by 3 experienced clinicians. (1) Anatomic dissections showed that all 3 approaches provided excellent exposure of the entire medial orbital wall. The transcaruncular and precaruncular approaches, however, (a) both resulted in exposure of the upper and lower tarsi when incisions greater than 10 mm were used; (b) both required a transition from the preseptal plane to the postseptal plane when combined with inferior fornix incisions. (2) A clinical study of 20 patients showed all reconstructions were possible without endoscopic assistance, resulting in no postoperative complications. Postoperative computed tomography scans showed anatomic orbital reconstruction in all patients judged as excellent by the clinicians. Medial orbital wall fractures can be successfully repaired using transconjunctival incisions without using endoscopes. The retrocaruncular approach surpasses the transcaruncular and precaruncular methods due to its decreased risk of postoperative lid complications and its ability to be directly carried to the inferior conjunctival fornix.

"Round-the-Clock" Surgical Access to the Orbit.

Objective To describe an algorithm to guide surgeons in choosing the most appropriate approach to orbital pathology. Methods A review of 12 selected illustrative cases operated on at the neurosurgical department of University of Pittsburgh Medical Center over 3 years from 2009 to 2011 was performed. Preoperative coronal magnetic resonance imaging and/or computed tomography views were compared using a "clock model" of the orbit with its center at the optic nerve. The rationale for choosing an external, endoscopic, or combined approach is discussed for each case. Results Using the right orbit for demonstration of the clock model, the medial transconjunctival approach provides access to the anterior orbit from 1 to 6 o'clock; endoscopic endonasal approaches provide access to the mid and posterior orbit and orbital apex from 1 to 7 o'clock. The lateral micro-orbitotomy gives access to the orbit from 8 to 10 o'clock. The frontotemporal craniotomy with orbital osteotomy accesses the orbit from 9 to 1 o'clock; addition of a zygomatic osteotomy to this extends access from 6 to 8 o'clock. Conclusions Combined, the approaches described provide 360 degrees of access to the entire orbit with the choice of the optimal approach guided primarily by the avoidance of crossing the plane of the optic nerve.

Optic Nerve Sheath Decompression

The purpose of this study was to determine the safety and efficacy of optic nerve sheath decompression (ONSD) with a medial transconjunctival approach for a variety of indications in a larger population of patients than has previously been reported. A retrospective chart review was performed on consecutive patients who underwent ONSD between January 1992 and December 2010. Before ONSD, all patients had documented evidence of progressive loss of visual acuity or visual field, or both. Postoperative follow-up visits were scheduled at 1 week, 1 month, and then every 3-6 months. Main outcome measures were visual acuity, visual fields, and surgical complications. Five hundred seventy-eight eyes of 331 patients underwent ONSD for progressive vision loss due to various indications, which included but were not limited to idiopathic intracranial hypertension (IIH), progressive nonarteritic ischemic optic neuropathy, and optic nerve drusen (OND). During a mean follow-up of 18.7 months (range, 1 week to 10 years), postoperative visual acuity remained stable or improved in 536 of 568 eyes (94.4%) and progressively worsened in 32 of 568 eyes (5.6%). Visual fields remained stable or improved in 257 of 268 eyes (95.9%) and progressive visual field loss occurred in 11 of 268 eyes (4.1%). There were no reported intraoperative complications. The most common postoperative complication was diplopia (6.0%). To our knowledge, this review represents the largest series of patients who have undergone ONSD for any indication. Our data are consistent with current literature supporting ONSD as a safe and effective procedure for IIH. Other indications for ONSD, such as progressive visual field loss associated with OND, warrant further study. Regardless of the indication, complications following ONSD with the technique described in this report are infrequent.

Outcomes of Optic Nerve Sheath Decompression for Visual Loss in Idiopathic Intracranial Hypertension

Purpose: To report our experience with optic nerve sheath decompression (ONSD) for visual loss in idiopathic intracranial hypertension (IIH).Methods: Six patients (7 eyes) with idiopathic intracranial hypertension and visual loss were involved. Five women and 1 man (mean age 42 years, ranged from 12 to 65 years) were operated at the Department of Ophthalmology, University Hospital, Hradec Kralove. Surgeries were performed by a standard medial transconjunctival approach and the sheaths were cut by three incisions. We have not seen any serious intra and postoperative complications. Only one patient developed transient double vision after surgery.Results: Visual functions improved in 5 patients. In one patient permanent visual loss with optic atrophy in both eyes occurred due to long-term duration of papilledema before referral to us.Conclusions: On the basis of our results, we believe that ONSD is safe and effective treatment of patients with IIH in vision-threatening cases after thoroughly balanced assessment of possible risks and gains.

Medial Transconjunctival Intrinsic Optic Nerve Biopsy: Surgical Technique and Indications

Aim: To describe a method of intrinsic optic nerve biopsy and its indications.Methods: Retrospective case series.Results: We report four cases that required intrinsic optic nerve biopsy for progressive optic neuropathy with uncertain diagnosis after negative systemic investigations. In all cases, a medial transconjunctival approach was used. There were no complications noted with this technique in the series, specifically there was no reported deterioration in vision. One case of neurosarcoidosis was confirmed. In the other three cases, the pathology results were non-diagnostic but ruled out serious causes such as central nervous system leukaemia relapse.Conclusion: Medial transconjunctival intrinsic optic nerve biopsy is a minimally invasive and safe technique. The technique is suitable for sampling pathology in the distal portion of the optic nerve. Optic nerve biopsy is indicated when there is significant loss of vision from an isolated optic nerve disease and all systemic investigations have failed to identify the cause, or where the clinical course of a presumed diagnosis is atypical.

Addition of a minimally invasive medial orbital approach in the endoscopic management of advanced sino‐orbital disease: Cadaver study with clinical correlations

Access to the medial orbit traditionally has been gained transcutaneously, with potential for associated soft tissue and lacrimal disruption. Endoscopic transnasal approaches to the medial orbit may be limited in certain scenarios by tumor presence or patient-specific factors. The medial transconjunctival approach, or transcaruncular approach, has been recently described for access to the medial orbit in orbital decompression and repair of medial blowout fractures. The aim of this study is to determine the utility of this minimally invasive external approach in the endoscopic management of advanced sino-orbital disease. This is a cadaver study with additional clinical correlations. The transcaruncular approach was combined with a transnasal endoscopic approach in cadaver dissections performed on eight sides. Five cases are described in which the transcaruncular approach was used as an adjunctive technique in advanced endoscopic sinus surgery. In cadaver dissection, the transcaruncular approach is a simple, reliable method to ligate the ethmoid arteries and place bony cuts along the medial orbital wall. In certain anatomic configurations, supraorbital dissection into the frontal sinus or anterior fossa may be achieved. In the cases examined, exposure of the medial orbital subperiosteal plane allowed for ligation of ethmoid arteries, assessment of periorbital invasion of disease, assistance in tumor dissection, and placement of a malleable retractor for protection of orbital contents. The transcaruncular approach to the medial orbit has certain advantages over the traditional open approach. Ligation of the ethmoid arteries, assessment of the lacrimal sac and periorbita for tumor invasion, protection of orbital contents, and en bloc resection of the periorbita and lamina papyrecea are possible through this route.

Optic Nerve Biopsy via a Medial Transconjunctival Orbitotomy Approach in the Diagnosis of Optic Nerve and Sheath Tumors

Purpose: To evaluate the role of optic nerve biopsy in the diagnosis and management of optic nerve and sheath tumors.Methods: Seven patients with progressive optic nerve and sheath tumors for whom treatment was deemed necessary were included in this study. Optic nerve biopsy via a medial transconjunctival orbitotomy approach was performed in all patientsResults: There were no complications related to the surgical procedure. Histopathological examination revealed that five patients had juvenile pilocytic astrocytoma (JPA) and two patients had optic nerve sheath meningioma (ONSM). All patients received external beam radiotherapy (EBRT).Conclusions: Many other benign and malignant optic nerve and sheath tumors have imaging features similar to those seen in JPA and ONSM. Therefore, it is important to establish histopathologic diagnosis before embarking on treatment. Furthermore, tissue diagnosis is required prior to EBRT in many institutions because of concerns about medicolegal liability. Optic nerve biopsy via a transconjunctival orbitotomy procedure in seven patients yielded histopathologic confirmation of the existing pathology and was not associated with any complications in this series.

Indikation und Technik der Optikusscheidenfensterung

An optic nerve sheath fenestration is indicated when papilloedema leads to progressive visual loss despite previous, conservative measures and when no cause of increased intracranial pressure can be indentified and eliminated. This rather rare constellation usually occurs in idiopathic intracranial hypertension. The procedure is performed via a medial transconjunctival orbitotomy. If headaches and neurologic symptoms other than visual deterioration prevail, the placement of a ventricular shunt is preferred. This review covers the symptoms of idiopathic intracranial hypertension and optic nerve sheath fenestration with its technical aspects and results.

ENDOSCOPIC TRANSCONJUNCTIVAL SURGICAL APPROACH TO THE OPTIC NERVE AND MEDIAL INTRACONAL SPACE

Surgical approaches to the orbit require great precision and care because of the functional and aesthetic importance of this region. Conventional approaches to the posterior orbit often require bone removal, may disrupt extraocular muscles, and may create external surgical scars. We conceived a transconjunctival surgical approach to the medial intraconal space that is aided by a minimally invasive endoscopic technique and avoids muscle transection. Assisted by a rigid endoscope measuring 2.7 mm in diameter, with 0- and 30-degree lenses, we made a medial conjunctival incision along the limbus to approach the medial intraconal space and optic nerve in 7 fresh cadaver heads (a total of 9 procedures). This approach provided direct and quick access to the medial intraconal space and intraorbital optic nerve with the use of endoscopes via an aesthetically acceptable conjunctival incision, and it provided an excellent view of the operative area. Unlike conventional techniques, this approach left the anatomy relatively undisturbed and did not require detachment of the medial rectus muscle. The endoscopic medial transconjunctival surgical approach provides minimally invasive direct access to the medial intraconal space and the intraorbital optic nerve. The approach is easy; minimally disturbs structures; and lends itself to biopsy, drainage, and even excision of selected lesions in this region without muscle transection and with aesthetically acceptable anatomic closure.

Intraorbital implantation of a stimulating electrode for an optic nerve visual prosthesis

Research into visual prosthetics is expected to revolutionize the treatment of blind patients with incurable outer retinal degenerative disease. Substantial evidence shows that useful visual sensations can be produced by controlled electrical stimulation of the optic nerve. To make the optic nerve visual prosthesis more acceptable, implantation techniques safer and less invasive than those previously used have been developed. A medial transconjunctival approach is now used to implant a stimulating electrode around the intraorbital section of the optic nerve. This new technique allows sufficient exposure of the nerve after detaching only one rectus muscle and performing a lateral canthotomy. Previously, an electrode was implanted in the intracranial part of the optic nerve, which required more invasive surgery. The new technique was first developed in cadavers and in patients undergoing eye enucleations. Finally, a 68-year-old blind man suffering from retinitis pigmentosa underwent long-term implantation. In this case report the authors describe the technique and outline some of the challenges involved.

Rapid Development of Amputation Neuroma Following Excision of an Orbital Cavernous Hemangioma

A 48-year-old man with left proptosis and signs of optic nerve compression underwent medial transconjunctival orbitotomy for an excisional biopsy of a posteromedial orbital cavernous hemangioma. The left eye once again became proptotic and painful only 5 weeks later because of a more anteriorly growing orbital mass, which was homogeneously hyperintense relative to orbital fat on both T1- and T2-weighted MRI studies. The tumor proved to be an amputation neuroma after total excision. The latter tumor is presumed to originate most probably from the transected branch of the oculomotor nerve innervating the medial rectus muscle, which remained paralytic after the first operation.

Endoscopically assisted reconstruction of orbital medial wall fractures.

Traditional surgical approaches to orbital medial wall fractures are either direct extraocular skin incisions or indirect bicoronal flap. However, these methods can leave remarkable orbital scars or scalp alopecia with the possible associated complications. A minimally invasive endoscopic technique with the assistance of a 2.7-mm, 30-degree telescope through a medial transconjunctival incision has been successfully used to reconstruct the orbital medial wall fractures. This technique was applied to four patients who had orbital medial wall fractures. Three patients also had concomitant orbital floor fractures. The other had associated superior orbital fissure syndrome. All patients were presented with limited eye movement, positive forced duction test, horizontal diplopia, and enophthalmos (3 mm to 6 mm) preoperatively. The entrapped periorbital tissues in the ethmoid sinus were completely reduced endoscopically. The bone defect of orbital medial wall was reconstructed with autogenous rib bone grafts under endoscopic control. The patients were followed up for 8 to 16 months with an average of 11 months. Three patients recovered completely without any residual eye symptoms after intervention. Clinically significant residual enophthalmos of 3 mm occurred in the patient with the superior orbital fissure syndrome. His eye movement limitation caused by entrapment of medial rectus muscle was relieved postoperatively. There was no donor-site morbidity or any complications related to the endoscopically assisted procedure. Endoscopically assisted medial transconjunctival approach to the orbital medial wall fractures is an excellent adjunct for the exposure and complete reduction of herniated periorbital tissue and bony reconstruction of the medial orbital wall.