gms | German Medical Science

ESBS 2005: Skull Base Surgery: An Interdisciplinary Challenge
7. Kongress der Europäischen Schädelbasisgesellschaft & 13. Jahrestagung der Deutschen Gesellschaft für Schädelbasischirurgie

18. - 21.05.2005, Fulda

The expanded endonasal approach: a fully endoscopic transnasal resection of the odontoid process

Meeting Contribution

  • Carl Snyderman - Minimally Invasive EndoNeurosurgical Center, Departments of Otolaryngology and Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, USA
  • Ricardo Carrau - Minimally Invasive EndoNeurosurgical Center, Departments of Otolaryngology and Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, USA
  • Amin Kassam - Minimally Invasive EndoNeurosurgical Center, Departments of Otolaryngology and Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, USA
  • Paul Gardner - Minimally Invasive EndoNeurosurgical Center, Departments of Otolaryngology and Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, USA
  • Richard Spiro - Minimally Invasive EndoNeurosurgical Center, Departments of Otolaryngology and Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, USA

ESBS 2005: Skull Base Surgery: An Interdisciplinary Challenge. 7th Congress of the European Skull Base Society held in association with the 13th Congress of the German Society of Skull Base Surgery. Fulda, 18.-21.05.2005. Düsseldorf: German Medical Science GMS Publishing House; 2009. Doc05esbs18

DOI: 10.3205/05esbs18, URN: urn:nbn:de:0183-05esbs186

Veröffentlicht: 27. Januar 2009

© 2009 Snyderman et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielfältigt, verbreitet und öffentlich zugänglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Introduction

Resection of the odontoid process is sometimes necessary for the treatment of basilar invagination with brainstem compression. This may be the result of rheumatoid degeneration with pannus formation or traumatic fracture and dislocation of the odontoid. With the advent of transnasal endoscopic approaches to the ventral skull base, resection of the odontoid may also be performed to provide access to tumors of the foramen magnum and adjacent areas.

The expanded endonasal approach to the ventral skull base allows access in the sagittal plane from the frontal sinus to the level of C2. A transnasal endoscopic approach for resection of the odontoid provides superior visualization compared to traditional transoral and transcervical approaches and may avoid some of the morbidity associated with these approaches. This paper describes our surgical technique and outcomes for patients with rheumatoid degeneration of the odontoid with brain stem compression.

Methods

We reviewed our experience with a fully endoscopic transnasal approach for resection of the odontoid process at the University of Pittsburgh Medical Center from 2004–2005. The technique has been described elsewhere [1] and is performed by a surgical team of an otolaryngologist and neurosurgeon operating simultaneously. The first step is a bilateral sphenoidotomy with resection of the posterior attachment of the nasal septum to the rostrum of the sphenoid. The mucosa of the posterior nasopharynx is then cauterized and elevated to expose the underlying paraspinal muscles (longus capitis and longus colli). The soft tissues and muscles are then resected to expose the underlying pharyngobasilar fascia. Resection of this dense fascia is facilitated by using a drill (3mm coarse diamond) to remove the cortical bone of the clivus starting at the sphenoidotomy and progressing inferiorly. The limits of exposure include the Eustachian tubes laterally, the floor of the sphenoid sinus superiorly, and the level of the soft palate inferiorly.

An image guidance system is used to identify the level of the ring of C1 and the bone is then exposed. The lower edge of the clivus is thinned with a drill and resected with a Kerrison rongeur. The central portion of C1 is then removed with the drill and the defect is widened laterally with the bone rongeur. The location of the underlying dens is then confirmed with image guidance and the central portion of the dens is drilled. When only a shell of outer cortical bone remains, the base of the dens is then detached from the body of C2. Blunt and sharp dissection of the attachments of the dens to the surrounding pannus allows mobilization and removal of the remaining bone.

Although resection of the pannus may not be necessary, we prefer to remove pannus with an ultrasonic aspirator until pulsations transmitted from the brainstem are observed. No reconstruction is necessary if there is no violation of the dura. The defect is covered with fibrin glue.

Due to inherent instability of the craniovertebral junction in these patients, posterior fusion of the cervical spine to the occiput is performed at the same operative event.

Results

We have operated on 5 patients using an endoscopic transnasal approach to the odontoid for rheumatoid degeneration with pannus formation. All of the patients presented with symptoms of brainstem compression.

All of the patients were successfully decompressed. The results in the patients with rheumatoid arthritis are shown in the table. None of these patients had intraoperative or postoperative cerebrospinal fluid leaks. Two patients required a tracheostomy; both of these patients had significant preoperative pharyngeal dysfunction. One elderly patient died from a pulmonary embolus on the day of discharge. With the exception of the single mortality, all patients showed improvement in symptoms and strength with followup of three or more months. None of the patients had hypernasal speech or nasal reflux in followup.

Discussion

The transnasal endoscopic approach to the odontoid is direct and provides access to the lower clivus, C1, and body of C2. The endoscope provides superior visualization compared to the microscope and facilitates a more complete removal of pannus if indicated. The only limitation is the ability to dissect below the body of C2 due to the level of the hard palate. The avoidance of pharyngeal and palatal incisions avoids the potential airway and swallowing morbidity associated with the transoral approach. Because the surgical opening is above the level of the soft palate, palatal dysfunction is avoided and there is no need to close the mucosal defect. No infections have been observed. There is also minimal pain and patients are able to resume an oral diet immediately if there were no swallowing problems preoperatively. A more rapid return to normal function and avoidance of operative morbidity should result in a shorter hospitalization with decreased cost of care.

Table 1 [Tab. 1]


References

1.
Kassam AB, Snyderman C, Gardner P, Carrau R, Spiro R. The Expanded Endonasal Approach: A Fully Endoscopic Transnasal Approach and Resection of the Odontoid Process: Technical Case Report. Neurosurgery. 2005;57(1 Suppl):E213