Direct epidural electrical stimulation of the optic nerve: a new method for intraoperative assessment of function

2008 ◽  
Vol 109 (4) ◽  
pp. 647-653 ◽  
Author(s):  
Roman Bošnjak ◽  
Mitja Benedièiè
Keyword(s):  
Electrical Stimulation ◽  
Optic Nerve ◽  
Optic Canal ◽  
Tumor Removal ◽  
Tuberculum Sellae Meningioma ◽  
Close Relationship ◽  
Tuberculum Sellae ◽  
The Impact ◽  
Light Flashes ◽  
Stimulation Of

Intraoperative visual system monitoring of lesions with a close relationship to the optic apparatus by using light flashes reportedly is difficult to perform, and the results are too unreliable to interpret. The authors used direct epidural electrical stimulation of the optic nerve (ON) during surgery instead of light flashes. Four patients were included in this feasibility study. In 3 patients—1 each harboring a planum sphenoidale meningioma, a tuberculum sellae meningioma, and an intraorbital ON sheath meningioma—2 stimulating needle electrodes were placed on each side of the ON just anterior to the optic canal, before unroofing the optic canal and an extradural anterior clinoidectomy. In the fourth patient, who harbored a frontotemporal astrocytoma, stimulation was applied at the exit of the ON from the canal. The electrically induced visual evoked potentials (eVEPs) were recorded from the scalp before, during, and after tumor removal. A typical eVEP consisted of N20 and N40 waves. The amplitude of the N40 wave varied up to 25% prior to tumor removal. In the patient with a symptomatic tuberculum sellae meningioma, the decompressive effect of opening the optic canal and the impact of manipulation during piecemeal tumor removal were detected by the eVEPs. In the patient with an ON sheath meningioma and light sensation, only the N20 wave was observed. Epidural electrical stimulation of the ON is a safe means of providing a stable signal and real-time information on nerve conduction during surgery. It may be a useful adjunct in improving visual outcomes postoperatively. Further clinical studies are necessary.

Endoscopic endonasal approach for a tuberculum sellae meningioma

2012 ◽  
Vol 32 (Suppl1) ◽  
pp. E8 ◽  
Author(s):  
Juan C. Fernandez-Miranda ◽  
Carlos D. Pinheiro-Neto ◽  
Paul A. Gardner ◽  
Carl H. Snyderman
Keyword(s):  
Optic Nerve ◽  
Carotid Artery ◽  
Internal Carotid Artery ◽  
Internal Carotid ◽  
Optic Canal ◽  
Csf Leak ◽  
Endoscopic Endonasal ◽  
Tuberculum Sellae Meningioma ◽  
Tuberculum Sellae

The authors present the technical and anatomical nuances needed to perform an endoscopic endonasal removal of a tuberculum sellae meningioma. The patient is a 47-year-old female with headaches and an incidental finding of a small tuberculum sellae meningioma with no vascular encasement, no optic canal invasion, but mild inferior to superior compression of the cisternal segment of the left optic nerve. Neuroophthalmology assessment revealed no visual defects. Treatment options included clinical observation with imaging follow-up studies, radiosurgery, and resection. The patient elected to undergo surgical removal and an endonasal endoscopic approach was the preferred surgical option. Preoperative radiological studies showed the presence of an osseous ring between the left middle and anterior clinoids, the so-called carotico-clinoidal ring. The surgical implications of this finding and its management are illustrated. The surgical anatomy of the suprasellar region is reviewed, including concepts such as the chiasmatic sulcus and limbus sphenoidale, medial and lateral optico-carotid recesses, and the paraclinoidal and supraclinoidal segments of the internal carotid artery. Emphasis is made in the importance of exposing the distal dural ring of the internal carotid artery and the precanalicular segment of the optic nerve for adequate intradural dissection. The endonasal route allows for early coagulation of the tumor meningeal supply and extensive resection of dural attachments, and importantly, provides an inferior to superior access to the infrachiasmatic region that facilitates complete tumor removal without any manipulation of the optic nerve. The lateral limit of dural removal is formed by the distal dural ring, which is gently coagulated after the tumor is resected. A 45° scope is used to inspect for any residual tumor, in particular at the entrance of the optic nerve into the optic canal and at the most anterior margin of the exposure (limbus sphenoidale). The steps for reconstruction are detailed and include intradural placement of dural substitute and extradural placement of the nasoseptal flap. The nuances for proper harvesting, positioning, and reinforcement of the flap are described. No lumbar drain was used. The patient had an uneventful recovery with no CSF leak or any other complications. Imaging follow-up at 6 months showed complete removal of the tumor. The patient had no sinonasal or neurological symptoms, and olfaction was fully preserved. The video can be found here: http://youtu.be/kkuV-yyEHMg.

Visual Outcome of Tuberculum Sellae Meningiomas after Extradural Optic Nerve Decompression

Neurosurgery ◽  
2006 ◽  
Vol 59 (3) ◽  
pp. 570-576 ◽  
Author(s):  
Tiit Mathiesen ◽  
Lars Kihlström
Keyword(s):  
Cerebrospinal Fluid ◽  
Optic Nerve ◽  
Diabetes Insipidus ◽  
Visual Outcome ◽  
Optic Canal ◽  
Visual Deterioration ◽  
Nerve Decompression ◽  
Visual Outcomes ◽  
Tuberculum Sellae

Abstract OBJECTIVE: Meningiomas of the tuberculum sellae have a close relationship with the optic apparatus. Even modern series show a 10 to 20% risk of visual deterioration after surgery. We have attempted to improve visual outcome by extradural decompression of the optic canal and anterior clinoid process, followed by intradural release of the optic nerve; this study provides an analysis of visual outcomes with this approach. METHODS: Treatment, histopathology, and follow-up data of 29 consecutive patients undergoing surgery for tuberculum sellae meningiomas with initial release of the optic nerve were prospectively collected. RESULTS: Radical tumor removal was possible in all 23 patients with primary tumors and in three out of six patients with recurrent tumors. All patients but two of the worst affected with preoperative visual compromise improved from surgery; there were no instances of visual deterioration. Five patients with normal preoperative vision remained intact and visual improvement was 22 (91%) out of 24 patients in the remaining patients. In total, 13 patients (42%) had completely normal vision at follow-up. Mainly patients younger than 60 years experienced complete normalization after surgery. Two patients underwent transsphenoidal surgery for cerebrospinal fluid leaks. Postoperative endocrinological symptoms were temporary diabetes insipidus in one patient and permanent diabetes insipidus in another patient undergoing elective sectioning of the pituitary stalk because of a recurrent tumor with invasive growth into the stalk. CONCLUSION: Adding early optic nerve decompression by extradural clinoidectomy and optic canal unroofing to a frontopterional approach seemed to improve visual outcomes because there were no instances of visual deterioration. Simpson Grade 1 to 2 removal was possible in all patients with primary surgery, whereas recurrent cases could only be treated with lower grades of radicality. Radical removal, however, required readiness to reoperate for cerebrospinal fluid leakage at the site of the drilled tumor origin in bone.

Pre-Clinical Applications of High-Definition Manometry System to Investigate Pelvic Floor Muscle Contribution to Continence Mechanisms in a Rabbit Model

2021 ◽  
Author(s):  
Samuel Sorkhi ◽  
Youngjin Seo ◽  
Valmik Bhargava ◽  
Mahadevan Raj Rajasekaran
Keyword(s):  
Electrical Stimulation ◽  
Anal Canal ◽  
Dynamic Pressure ◽  
Rabbit Model ◽  
Puborectalis Muscle ◽  
High Definition ◽  
System Pressure ◽  
Vaginal Canal ◽  
The Impact ◽  
Stimulation Of

External anal sphincter (EAS), external urethral sphincters and puborectalis muscle (PRM) have important roles in the genesis of anal and urethral closure pressures. In the present study, we defined the contribution of these muscles alone and in combination to the sphincter closure function using a rabbit model and a high-definition manometry (HDM) system. A total of 12 female rabbits were anesthetized and prepared to measure anal, urethral, and vaginal canal pressures using a HDM system. Pressure was recorded at rest, and during electrical stimulation of the EAS and PRM. A few rabbits (n=6) were subjected to EAS injury and the impact of EAS injury on the closure pressure profile was also evaluated. Anal, urethral, and vaginal canal pressures recorded at rest and during electrical stimulation of EAS and PRM demonstrated distinct pressure profiles. EAS stimulation induced anal canal pressure increase whereas PRM stimulation increased the pressures in all the three orifices. Electrical stimulation of EAS after injury resulted in about 19% decrease in anal canal pressure. Simultaneous electrical stimulation of EAS and PRM resulted in an insignificant increase of individual anal canal pressures when compared to pressures recorded after EAS or PRM stimulations alone. Our data confirm that HDM is a viable system to measure dynamic pressure changes within the three orifices and to define the role of each muscle in the development of closure pressures within these orifices in preclinical studies.

Relation of Posttetanic Potentiation to Subnormality of Lateral Geniculate Potentials

1957 ◽  
Vol 188 (2) ◽  
pp. 238-244 ◽  
Author(s):  
Edward V. Evarts ◽  
John R. Hughes
Keyword(s):  
Electrical Stimulation ◽  
Optic Nerve ◽  
Posttetanic Potentiation ◽  
Postsynaptic Response ◽  
Lateral Geniculate ◽  
Decerebrate Cats ◽  
Stimulation Of

The lateral geniculate response to electrical stimulation of the optic nerve was recorded in decerebrate cats and in cats anesthetized with Nembutal. Tetanization of the optic nerve at 500/sec. for 20 seconds in nembutalized cats produced a prolonged second subnormality of the geniculate postsynaptic response. Further tetanization during tetanically-induced second subnormality produced posttetanic potentiation (PTP). The degree of PTP (expressed in percentage of the pretetanic level) of the postsynaptic response following a 20-second tetanus was proportional to the degree of second subnormality present at the time the tetanus was applied. PTP was also found to occur during the subnormality which followed a brief train of optic nerve shocks, and during LSD-induced subnormality. PTP of postsynaptic lateral geniculate potentials occurred only rarely in the absence of some form of intentionally induced subnormality.

Dual actions of isthmic input to tectal neurons in a reptile, Gekko gekko

1999 ◽  
Vol 16 (5) ◽  
pp. 889-893 ◽  
Author(s):  
STEPHEN A. GEORGE ◽  
GANG-YI WU ◽  
WEN-CHANG LI ◽  
SHU-RONG WANG
Keyword(s):  
Electrical Stimulation ◽  
Optic Nerve ◽  
Optic Tectum ◽  
Nucleus Isthmi ◽  
Postsynaptic Potentials ◽  
Tectal Neurons ◽  
Electrical Connections ◽  
Stimulation Of

We analyzed postsynaptic potentials and dye-labeled morphology of tectal neurons responding to electrical stimulation of the optic nerve and of the nucleus isthmi in a reptile, Gekko gekko, in order to compare with previously reported interactions between the optic tectum and the nucleus isthmi in amphibians and birds. The results indicate that isthmic stimulation exerts inhibitory and excitatory actions on tectal cells, similar to dual isthmotectal actions in amphibians. It appears that dual actions of the isthmotectal pathway in amphibians and reptiles are shared by two subdivisions of the nucleus isthmi in birds. The morphology of tectal cells responding to isthmic stimulation is generally similar to that of tectoisthmic projecting neurons, but they differ particularly in that some tectoisthmic cells bear numerous varicosities whereas cells receiving isthmic afferents do not. Thus, it is likely that at least some tectoisthmic cells may not be in the population of tectal cells that can be affected by isthmic stimulation. Forty-four percent of injections resulted in dye-coupled labeling, suggesting extensive electrical connections between tectal cells in reptiles.

Endonasal Transsphenoidal Removal of Tuberculum Sellae Meningiomas: Technical Note

Neurosurgery ◽  
2004 ◽  
Vol 55 (1) ◽  
pp. 239-246 ◽  
Author(s):  
Shon W. Cook ◽  
Zachary Smith ◽  
Daniel F. Kelly
Keyword(s):  
Cerebrospinal Fluid ◽  
Optic Nerve ◽  
Nerve Compression ◽  
Transsphenoidal Approach ◽  
Fat Graft ◽  
Operating Microscope ◽  
Endonasal Approach ◽  
Tumor Removal ◽  
Tuberculum Sellae ◽  
Optic Nerve Compression

Abstract OBJECTIVE: Tuberculum sellae meningiomas traditionally have been removed through a transcranial approach. More recently, the sublabial transsphenoidal approach has been used to remove such tumors. Here, we describe use of the direct endonasal transsphenoidal approach for removal of suprasellar meningiomas. METHODS: Three women, aged 32, 34, and 55 years, each sought treatment for visual loss and headaches. In each patient, magnetic resonance imaging (MRI) showed a suprasellar mass causing optic chiasmal and optic nerve compression (average size, 2 × 2 cm). All three patients underwent tumor removal via an endonasal approach with the operating microscope. Suprasellar exposure was facilitated by removal of the posterior planum sphenoidale. Ultrasound was used to help define tumor location before dural opening. The extent of tumor removal was verified with angled endoscopes in all patients, and with intraoperative MRI in one patient. The surgical dural and bony defects were repaired in all patients with abdominal fat, titanium mesh, and 2 to 3 days of cerebrospinal fluid lumbar drainage. Nasal packing was not used. RESULTS: There were no postoperative cerebrospinal fluid leaks or meningitis. One patient required a reoperation 2 weeks after surgery to reduce the size of her fat graft, which was causing optic nerve compression; within 24 hours, her vision rapidly improved. At 3 months after surgery, all three patients had normal vision, no new endocrinopathy, and no residual tumor on MRI. At 10 months after surgery, one patient had a small asymptomatic tumor regrowth seen on MRI. CONCLUSION: The endonasal approach with the operating microscope appears to be an effective minimally invasive method for removing relatively small midline tuberculum sellae meningiomas. Intraoperative ultrasound, the micro-Doppler probe, and angled endoscopes are useful adjuncts for safely and completely removing such tumors. Longer follow-up is needed to monitor for tumor recurrence in these patients.

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