The increasing popularity of minimally invasive neurosurgery has led to the development of transnasal expanded approaches for the treatment of skull base lesions. One of the greatest challenges in safely accomplishing resection of tumors, particularly intradural lesions, is effective hemostasis. Over the past 7 years the authors have progressively developed an organized approach to address this challenge. This has required the development of new instrumentation as well as variations on standard techniques. In this report they present the technique that has evolved at their institution for endoneurosurgical hemostasis.
Amin Kassam, Carl H. Snyderman, Ricardo L. Carrau, Paul Gardner and Arlan Mintz
Amin Kassam, Ricardo L. Carrau, Carl H. Snyderman, Paul Gardner and Arlan Mintz
Harvey Cushing first popularized the transsphenoidal route to the sella turcica, and Jules Hardy subsequently refined it by adding the operating microscope. Over the ensuing decades, attempts at extending the application of this approach have been advanced by Edward Laws and others. With the evolution of endoscopic approaches, the natural expansion of their use to intradural lesions followed. For the expanded endonasal approach to become a viable option, the paramount concerns surrounding consistent reconstruction of the dura mater must be overcome. In this review the authors chronicle the evolution of the reconstruction technique they currently use after performing expanded endonasal approaches. They also report the use of a balloon stent to buttress the reconstruction and counter the effects of graft migration and cerebrospinal fluid fistula formation. The technique described in this report represents an important step forward in the reconstruction of defects resulting from expanded endonasal approaches.
Amin B. Kassam, Paul Gardner, Carl Snyderman, Arlan Mintz and Ricardo Carrau
The middle third of the clivus and the region around the petrous internal carotid artery (ICA) is a difficult area of the skull base in terms of access. This is a deep area rich with critical neurovascular structures, which is often host to typical skull base diseases. Expanded endoscopic endonasal approaches offer a potential option for accessing this difficult region. The objective of this paper was to establish the clinical feasibility of gaining access to the paraclival space in the region of the middle third of the clivus, to provide a practical modular and clinically applicable classification, and to describe the relevant critical surgical anatomy for each module.
The anatomical organization of the region around the petrous ICA, cavernous sinus, and middle clivus is presented, with approaches divided into zones. In an accompanying paper in this issue by Cavallo, et al., the anatomy of the pterygopalatine fossa is presented; this was observed through cadaveric dissection for which an expanded endonasal approach was used. In the current paper the authors translate the aforementioned anatomical study to provide a clinically applicable categorization of the endonasal approach to the region around the petrous ICA. A series of zones inferior and superior to the petrous ICA are described, with an illustrative case presented for each region.
The expanded endonasal approach is a feasible approach to the middle third of the clivus, petrous ICA, cavernous sinus, and medial infratemporal fossa in cases in which the lesion is located centrally, with neurovascular structures displaced laterally.
Amin Kassam, Carl H. Snyderman, Arlan Mintz, Paul Gardner and Ricardo L. Carrau
Transsphenoidal approaches have been used for a century for the resection of pituitary and other sellar tumors. More recently, the standard endonasal approach has been expanded to provide access to other, parasellar lesions. With the addition of the endoscope, this expansion carries significant potential for the resection of skull base lesions.
The anatomical landmarks and surgical techniques used in expanded (extended) endoscopic approaches to the rostral, anterior skull base are reviewed and presented, accompanied by case illustrations of each segment (or module) of approach. The rostral half of the anterior skull base is divided into modules of approach: sellar/parasellar, transplanum/transtuberculum, and transcribriform. Case illustrations of successful resections of lesions with each module are presented and discussed.
Endoscopic, expanded endonasal approaches to rostral anterior skull base lesions are feasible and hold great potential for decreased morbidity. The effectiveness and appropriate use of these techniques must be evaluated by close examination of outcomes as case series expand.
Amin Kassam, Carl H. Snyderman, Arlan Mintz, Paul Gardner and Ricardo L. Carrau
Transsphenoidal approaches have been used for a century for the resection of pituitary and other sellar tumors. Recently, however, the standard endonasal approach has been expanded to provide access to other parasellar lesions. With the addition of the endoscope, this expansion has significant potential for the resection of skull base lesions.
The anatomical landmarks and surgical techniques used in expanded (extended) endoscopic approaches to the clivus and cervicomedullary junction are reviewed and presented, accompanied by case illustrations of each segment (or module) of approach.
The caudal portion of the midline anterior skull base and the cervicomedullary junction is divided into modules of approach: the middle third of the clivus, its lower third, and the cervicomedullary junction. Case illustrations of successful resections of lesions via each module of the approach are presented and discussed.
Endoscopic expanded endonasal approaches to caudally located midline anterior skull base and cervicomedullary lesions are feasible and hold great potential for decreased morbidity. The effectiveness and appropriate use of these techniques must be evaluated by close examination of outcomes as case series expand.
Amin Kassam, Ajith J. Thomas, Carl Snyderman, Ricardo Carrau, Paul Gardner, Arlan Mintz, Hilal Kanaan, Michael Horowitz and Ian F. Pollack
The authors reviewed their experience with endoscopic approaches to determine their safety and efficacy in the treatment of pediatric patients who harbor skull base lesions. Although they were interested in ascertaining outcomes after surgery as well as validating and defining indications and limitations of these approaches, the authors recognized that the follow-up duration was inadequate to assess long-term outcomes.
The authors conducted a retrospective review of all endoscopic procedures performed at their institution between January 2000 and September 2005. The procedures were categorized into a series of anatomical modular approaches.
Twenty-five patients 18 years of age or younger were identified. The surgical goals were individualized and included gross-total resection, partial resection, biopsy, decompression of neural structures, and repair of a cerebrospinal fluid (CSF) leak. One patient required an open procedure in addition to the expanded endonasal approach for definitive therapy. No patient suffered a neurological deficit, vascular injury, or central nervous system infection. A CSF leak was the most common complication and occurred in two (8%) of the 25 patients.
In well-selected patients, the expanded endonasal approach represents a safe, effective, and minimally invasive technique for the treatment of skull base lesions in children. Incremental experience is needed for acquiring the skills with endoscopic techniques to progress to the more complex modular approaches.
Daniel M. Prevedello, Amin B. Kassam, Ricardo L. Carrau, Carl H. Snyderman, Ajith Thomas, Paul Gardner, Arlan Mintz, Lisa Vecchione and Joseph Losee
✓Teratomas are neoplasms composed of tissues from all three germ layers with varying degrees of differentiation. They are most commonly found in the sacrococcygeal and gonadal regions and rarely occur in the head and neck region. A teratoma is termed “epignathus” when it arises from the skull base or hard palate and is located in the oral cavity. The authors describe a case of a giant epignathus teratoma originating in the skull base of a neonate, extending bilaterally via two pedicles throughout the hard palate and protruding through the oral cavity. The tumor was completely resected using a transpalatal endoscopic endonasal approach. The excised tumor proved to be an immature teratoma with well-differentiated yolk sac elements. At the 1-year follow-up the patient showed no evidence of tumor recurrence and the child remains neurologically intact.
This report demonstrates the use of a transpalatal endonasal corridor in a preterm infant. This approach provided an ample corridor into the ventral skull base without the need for external excisions and/or disruption of osseous elements.
Amin B. Kassam, Paul A. Gardner, Arlan Mintz, Carl H. Snyderman, Ricardo L. Carrau and Michael Horowitz
✓Paraclinoidal aneurysms, especially superior hypophyseal artery (SHA) aneurysms (with medial projection), can be challenging to access via a pterional craniotomy and damage to the optic nerve can occur during surgery. The authors have previously reported on endonasal clipping and aneurysmorrhaphy of a vertebral artery aneurysm following proximal and distal protection of the aneurysm using partial coil embolization. To the best of the authors' knowledge no unprotected aneurysm has been clipped using an endonasal approach.
The 56-year-old woman in this report was found to have two unruptured aneurysms: an anterior communicating artery (ACoA) aneurysm and an SHA aneurysm. An endoscopic endonasal, transplanar–transsellar approach was used to successfully clip the SHA aneurysm. Proximal and distal control was obtained endonasally prior to successful clip occlusion of the aneurysm. The ACoA aneurysm was clipped via a pterional craniotomy during the same anesthetic session. This report shows that it is possible to successfully clip a medially projecting, paraclinoidal aneurysm using an endonasal approach. Such cases must be chosen with extreme caution and only performed by surgeons with significant experience with both endoscopic endonasal approaches and neurovascular surgery.
Amin B. Kassam, Allan D. Vescan, Ricardo L. Carrau, Daniel M. Prevedello, Paul Gardner, Arlan H. Mintz, Carl H. Snyderman and Albert L. Rhoton Jr.
✓ The purpose of this study was to describe the technique used to safely identify the petrous carotid artery during expanded endonasal approaches to the skull base. A series of 20 cadaveric studies was undertaken to isolate the vidian artery and nerve and to use them as landmarks to the petrous internal carotid artery (ICA). Twenty-five consecutive paraclival endoscopic cases were also reviewed to determine the consistency of the vidian artery in vivo as an intraoperative landmark to the ICA. These data were then correlated with results from a separate study in which computed tomography scans from 44 patients were evaluated to delineate the course of the vidian canal and its relationship to the petrous ICA. In all 20 cadaveric dissections and all 25 surgical cases, the vidian artery was consistently identified and could be reliably used as a landmark to the ICA. The correlation between anatomical and clinical data in this paper supports the consistent use of the vidian artery as an important landmark to the petrous ICA.
Paul Gardner, Amin Kassam, Carl Snyderman, Arlan Mintz, Ricardo Carrau and John J. Moossy
✓ Cerebrospinal fluid (CSF) leakage following endoscopic endonasal skull base resection can be a significant problem. A method for securing tissue grafts is needed. In this paper the authors used an endonasal suturing device to secure the graft reconstruction following endonasal tumor resection.
The U-Clip anastomotic device (Medtronic), developed for cardiovascular anastomoses, was used to secure the tissue graft to native dura. A specialized needle driver and hemoclip applier were used for the application and deployment of this device. No suture tying was necessary, facilitating its endonasal application.
The graft was successfully secured in its desired position to native dura by using the U-Clip anastomotic device. The patient did not suffer a postoperative CSF leak, and postoperative imaging and endoscopy revealed that the graft was in a good position. There was no complication from the use of the device.
The U-Clip anastomotic device can be used as a suture device during endonasal surgery. It may prevent tissue graft migration and help prevent CSF leakage.