Endoscope-assisted clipping of a superior hypophyseal artery aneurysm without removal of the anterior clinoid process. Case report

Endoscopically Assisted Release Surgery for Idiopathic Spinal Cord Herniation: Technical Case Instruction

BACKGROUND AND IMPORTANCE

Idiopathic spinal cord herniation through a defect in the ventral dura mater is rare and typically results in progressive myelopathy. Various surgical procedures to release the tethered spinal cord can prevent the progression of myelopathy; however, the optimal procedure has not yet been established. We describe techniques using endoscopic assistance to minimize spinal cord manipulation.

CLINICAL PRESENTATION

A 60-year-old woman presented with Brown-Séquard syndrome. Magnetic resonance imaging demonstrated ventral displacement of the spinal cord at T3-4. Right T2, T3, T4, and T5 hemilaminectomies and T4 pediculectomy were performed. After paramedian durotomy and transection of the dentate ligament, we identified a defect in the inner layer of the dura mater ventrally and found the spinal cord incarcerated in a pocket between the inner and outer layers. The spinal cord was adherent to the dura at the caudal end of the defect. The defect was extended caudally on the right under microscopic observation. On the left, which could not be visualized under the microscope, the adhesions were dissected under endoscopic guidance. After complete spinal cord untethering, the defect was closed using collagen matrix. The patient's motor weakness fully recovered, and she was walking independently at the time of discharge.

CONCLUSION

Endoscopic assistance for release of thoracic spinal cord herniation is useful for minimizing intraoperative spinal cord manipulation.

Keyhole clipping of a low-lying basilar apex aneurysm without posterior clinoidectomy utilizing endoscopic indocyanine green video angiography

Background:

Basilar apex (BX) aneurysms are surgically challenging due to their anatomic location, need to traverse neurovascular structures, and proximity to multiple perforator arteries. Surgical approaches often require extensive bone resection and neurovascular manipulation. Visualization of low-lying BX aneurysms is typically obscured by the posterior clinoid and upper clivus and poses a unique challenge. Subtemporal or anterolateral approaches with a posterior clinoidectomy are often required to achieve adequate exposure, though these maneuvers can add invasiveness, risk, and morbidity to the procedure. Endoscopes and, more recently, fluoroscopic angiography capable endoscopes offer the possibility of providing improved visualization with less exposure allowing for minimally invasive clipping.

Case Description:

We present the case of a 42-year-old female with incidentally found 5 mm middle cerebral artery and 5 mm BX aneurysms. She underwent a minimally invasive supraorbital keyhole craniotomy for the clipping of both aneurysms. While the posterior clinoid obstructed the necessary visualization for the BX aneurysm, use of endoscopy and endoscopic fluoroscopic angiography allowed for safe and successful clipping without the need for a posterior clinoidectomy.

Conclusion:

This represents the first reported case of a BX aneurysm clipping through a minimally invasive keyhole craniotomy using endoscopic indocyanine green video angiography. Use of endoscopic indocyanine green angiography, combined with keyhole endoscopic approaches, allows for safe minimally invasive clipping of challenging posterior circulation aneurysms.

Efficacy of Endoscopic Fluorescein Video Angiography in Aneurysm Surgery—Novel and Innovative Assessment of Vascular Blood Flow in the Dead Angles of the Microscope

BACKGROUND: In aneurysm surgery, assessment of the blood flow around the aneurysm is crucial. Recently, intraoperative fluorescence video angiography has been widely adopted for this purpose. However, the observation field of this procedure is limited to the microscopic view, and it is difficult to visualize blood flow obscured by the skull base anatomy, parent arteries, and aneurysm.

OBJECTIVE: To demonstrate the efficacy of a new small-caliber endoscopic fluorescence video angiography system employing sodium fluorescein in aneurysm surgery for the first time.

METHODS: Eighteen patients with 18 cerebral aneurysms were enrolled in this study. Both microscopic fluorescence angiography and endoscopic fluorescein video angiography were performed before and after clip placement.

RESULTS: Endoscopic fluorescein video angiography provided bright fluorescence imaging even with a 2.7-mm-diameter endoscope and clearly revealed blood flow within the vessels in the dead angle areas of the microscope in all 18 aneurysms. Consequently, it revealed information about aneurysmal occlusion and perforator patency in 15 aneurysms (83.3%) that was not obtainable with microscopic fluorescence video angiography. Furthermore, only endoscopic video angiography detected the incomplete clipping in 2 aneurysms and the occlusion of the perforating branches in 3 aneurysms, which led to the reapplication of clips in 2 aneurysms.

CONCLUSION: The innovative endoscopic fluorescein video angiography system we developed features a small-caliber endoscope and bright fluorescence images. Because it reveals blood flow in the dead angle areas of the microscope, this novel system could contribute to the safety and long-term effectiveness of aneurysm surgery even in a narrow operative field.

The Roles of Endoscope in Aneurysmal Surgery

The neuroendoscope, with its higher magnification, better observation, and additional illumination, can provide us information that may not be available with the microscope in aneurysm surgery. Furthermore, recent advancement of the holding systems for the endoscope allows surgeons to perform microsurgical manipulation using both hands under the simultaneous endoscopic and microscopic monitoring. With this procedure, surgeons can inspect hidden structures, dissect perforators at the back of the aneurysm, identify important vessel segments without retraction of the aneurysm or arteries, and check for completion of clipping. In addition, we have recently applied endoscopic indocyanine green video angiography to aneurysm surgery. This newly developed technique can offer real-time assessment of the blood flow of vasculatures in the dead angles of the microscope, and will reduce operative morbidity related to vascular occlusion, improve the durability of aneurysm surgery by reducing incomplete clipping, and thus promote the outcome of aneurysm surgery.

Surgical anatomy of endoscope-assisted approaches to common aneurysm sites

BACKGROUND

The endoscope is being introduced as an adjuvant to improve visualization of certain areas in open cranial surgery.

OBJECTIVE

To describe the endoscopic anatomy of common aneurysm sites and to compare it with the microsurgical anatomy.

METHODS

Pterional, anterior interhemispheric, and subtemporal approaches to the most common aneurysm sites were examined in cadaveric heads under the surgical microscope and with the endoscope.

RESULTS

The endoscopic view, particularly with the angled endoscopes, provides a significant improvement compared with the microscopic view, especially for poorly visualized sites such as the medial aspect of the supraclinoid carotid artery and its branches, the area below the anterior perforated substance and optic tract, and the carotid and basilar bifurcations. The endoscope aided in the early visualization of perforating branches at each aneurysm site except the middle cerebral artery. Small-diameter optics (2.7 mm) provided greater space for dissection and less potential for tissue damage in narrow places, whereas the larger 4-mm diameter optics provided better visualization and less panoramic distortion. The positioning of the endoscope for each aneurysm site is reviewed.

CONCLUSION

The endoscope provides views that complement or improve the microscopic view at each aneurysm site except the middle cerebral artery. Endoscopy training and a thorough knowledge of endoscopic vascular anatomy are essential to safely introduce endoscopic assistance in vascular surgery.

Pupil-sparing oculomotor nerve palsy caused by upward compression of a large posterior communicating artery aneurysm. Case report

A 69-year-old woman without diabetes or hypertension presented with a large posterior communicating artery aneurysm projecting beneath the oculomotor nerve manifesting as a 2-week history of progressive diplopia. Neurological examination revealed external ophthalmoplegia and blepharoptosis without pupil involvement. Neuroimaging showed a large aneurysm in the left internal carotid artery projecting postero-inferiorly. Craniotomy and neck clipping of the aneurysm revealed the origin at the junction of the internal carotid artery and posterior communicating artery, and elevation of the oculomotor nerve. Pupil-sparing oculomotor nerve palsy is often assumed to be caused by ischemic injury such as hypertension and diabetes mellitus. Sometimes compressive lesion can cause pupil-sparing oculomotor nerve palsy with a short interval from the onset of symptoms to diagnosis. Despite the 2-week interval from the onset of symptoms, this patient presented with pupil-sparing oculomotor nerve palsy caused by compressive lesion. Involvement or sparing of the pupil is often considered to be the most important criterion in the diagnosis of isolated oculomotor nerve palsy. This unique case demonstrated that unusual compressive lesions must be taken into consideration in the diagnosis of pupil-sparing oculomotor nerve palsy.

Endoscopic indocyanine green video angiography in aneurysm surgery: an innovative method for intraoperative assessment of blood flow in vasculature hidden from microscopic view

Recently, intraoperative fluorescence video angiography using indocyanine green (ICG) has been widely used in aneurysm surgery. This is a simple and useful method to confirm complete occlusion of the aneurysm lumen and preservation of blood flow in the arteries around the aneurysm. However, the observation field of ICG video angiography is limited under a microscope, making it difficult to confirm the flow in the arteries behind the parent arteries or aneurysm. The authors developed a new technique of intraoperative endoscopic ICG video angiography to assess the blood flow in perforating arteries hidden by the parent arteries or aneurysm. The endoscope emits excitation light with a wavelength of approximately 800 nm, and video images were obtained through a cut filter. The authors used this ICG fluorescence endoscope in treating 3 patients with unruptured cerebral aneurysms. During clip placement, the endoscope was inserted to confirm aneurysm occlusion. Then, ICG was intravenously administered, and the fluorescence in the vessels was observed via the endoscope as well as under the microscope. The blood flow in the perforating arteries was clearly identified, and no procedural complication occurred. The authors conclude that the technique is very useful and facilitates intraoperative real-time assessment of the patency of perforating arteries behind parent arteries or aneurysms.

Supracerebellar infratentorial endoscopically controlled resection of pineal lesions: case series and operative technique

OBJECT

The heterogeneous clinical manifestations and operative characteristics of pathological entities in the pineal region represent a significant challenge in terms of patient selection and surgical approach. Traditional surgical options have included endoscopic transventricular resection; open supratentorial microsurgical approaches through the midline, choroidal fissure, lateral ventricle, and tentorium; and supracerebellar infratentorial (SCIT) approaches through the posterior fossa. The object of the current study was to review the preoperative characteristics and outcomes for a cohort of patients treated purely via the novel endoscopically controlled SCIT approach.

METHODS

A single-institution series of 9 consecutive patients (4 male and 5 female patients [10 total cases]; mean age 21 years, range 6-37 years) treated via the endoscopically controlled SCIT approach for a pathological entity in the pineal region was retrospectively reviewed. The mean follow-up time was 13.2 months.

RESULTS

The endoscopically controlled SCIT approach was successfully used to approach a variety of pineal lesions, including pineal cysts (6 patients), epidermoid tumor, WHO Grade II astrocytoma (initial biopsy and recurrence), and malignant mixed germ cell tumor (1 patient each). Gross-total resection and/or adequate cyst fenestration was achieved in 8 cases. Biopsy with conservative debulking was performed for the single case of low-grade astrocytoma and again at the time of recurrence. The mean preoperative tumor and cyst volumes were 9.9 ± 4.4 and 3.7 ± 3.2 cm(3), respectively. The mean operating times were 212 ± 71 minutes for tumor cases and 177 ± 72 minutes for cysts. Estimated blood loss was less than 150 ml for all cases. A single case (pineal cyst) was converted to an open microsurgical approach to enhance visualization. There were no operative complications, as well as no documented CSF leaks, additional CSF diversion procedures, or air emboli. Seven patients underwent concomitant third ventriculostomy into the quadrigeminal cistern. At the time of the last follow-up evaluation, all patients had a stable or improved modified Rankin Scale score.

CONCLUSIONS

The endoscopically controlled SCIT approach may be used for the biopsy and resection of appropriately selected solid tumors of the pineal region, in addition to the fenestration and/or resection of pineal cysts. Preoperative considerations include patient presentation, anticipated disease and vascularity, degree of local venous anatomical distortion, and selection of optimal paramedian trajectory.

Loss of visual evoked potential following temporary occlusion of the superior hypophyseal artery during aneurysm clip placement surgery. Case report

The authors report a case in which a 62-year-old woman with a history of subarachnoid hemorrhage due to a ruptured aneurysm was found to have a de novo paraclinoid aneurysm in the right internal carotid artery during a routine medical examination. Surgical clip placement was performed via a contralateral pterional approach under visual evoked potential (VEP) monitoring. The superior hypophyseal artery (SHA) was found to originate from the aneurysm body. The artery was temporarily occluded prior to application of the clip to the aneurysm neck. The VEP signal was lost 3 minutes after the SHA was occluded, and the potentials gradually recovered 10 minutes after the artery was released. The disappearance of VEP signal was reproducible with SHA occlusion. The clip was applied to the aneurysm body to preserve the origin of the SHA. The patient did not have any deterioration of vision after surgery. Intraoperative VEP monitoring can be used to help determine whether the SHA can be sacrificed safely.

Microneurosurgical management of carotid-ophthalmic aneurysms

OBJECTIVE

To evaluate the management of carotid-ophthalmic segment aneurysms (COA) with modern microneurosurgical techniques and instruments.

METHOD

Sixty patients with COA undergoing microsurgical clipping between March 1994 and June 2002 in the Department of Neurosurgery, Tiantan Hospital, Beijing, were analyzed retrospectively. Neuroimaging included digital subtraction angiography (DSA), MRI, CT, three-dimensional CT angiography and three-dimensional DSA. From 1998, intraoperative Doppler ultrasound monitoring and endoscope-assisted techniques were used.

RESULT

All aneurysms were completely obliterated without either recurrence or death. The morbidity rate of surgery prior to 1998 was 21.7%, which decreased to 13.7% after 1998 (mean 18.3% for the whole study period).

CONCLUSION

Preoperative planning based on neuroimaging is very valuable. Advances in neuroimaging, endoscope-assisted techniques and intraoperative Doppler ultrasound monitoring are useful to decrease postoperative complications. Microneurosurgical techniques are optimal for the management of COA with ever lessening morbidity.

New device for endoscopic image display during microsurgical clipping of cerebral aneurysms--technical note--

Endoscopy in microsurgery is most effective when a single surgeon can monitor both endoscopic and microscopic images simultaneously. However, monitoring systems of this kind, such as a contemporary microscope equipped with a picture-in-mode function, are expensive. The present display system is connected to the endoscope video camera and mounted on the surgeon's head. The liquid crystal display is positioned just under the microscope eyepieces, so reducing the need for the surgeon to refocus and redirect the gaze during surgery. This system allows nearly simultaneous endoscopic and microscopic monitoring. No changes to the surgical microscope are necessary.

Simultaneous microscopic and endoscopic monitoring during surgery for internal carotid artery aneurysms

Object. The authors of this study evaluated the efficacy of simultaneous microscopic and endoscopic monitoring during surgery for internal carotid artery (ICA) aneurysms.

Methods. The endoscopic technique was applied during microsurgery in 11 patients with 13 aneurysms. Nine of these lesions were located on the posterior communicating artery (PCoA), three in the paraclinoid region, and one on the anterior choroidal artery (AChA). Eight patients had unruptured aneurysms and three had ruptured aneurysms. The endoscope was introduced after first exposing the aneurysm through the microscope and was gripped firmly by an air-locked holding arm fitted with a steering system throughout the entire surgery, including dissection of the perforating arteries and application of the aneurysm clips.

Regarding paraclinoid aneurysms, clips were applied through direct visualization of the ophthalmic artery and the proximal neck. In a case involving a superior hypophyseal artery aneurysm in the paraclinoid segment, a ring clip was applied without removing the bone structure around the optic canal. In all aneurysms of the PCoA and the AChA, perforating arteries behind the lesion were identified and dissected using endoscopic control. The aneurysm clip was applied in the best position in a single attempt in 10 of 11 patients. There was no surgical complication related to the endoscopic procedures.

Conclusions. Simultaneous monitoring with the microscope and endoscope is extremely useful in applying clips to ICA aneurysms. This combined method allows for direct dissection of the aneurysm, perforating vessels, and the main trunk in an area not visible through the microscope's eyepiece and promises better surgical results.