Posterolateral odontoidectomy for irreducible atlantoaxial dislocation: a technical case report

Case Report: Posterolateral Epidural Supra-C2-Root Approach (PESCA) for Biopsy of a Retro-Odontoid Lesions in Same Sitting After Occipitocervical Fixation and Decompression in a Case of Crowned Dens Syndrome With Brainstem Compression and Displacement

Background

‘Crowned dens syndrome' (CDS) is a special form of calcium pyrophosphate dihydrate deposition disease which is characterized radiologically by a halo-like or crown-like distribution in the periodontoid region and clinically by cervical pain. Herein, we will describe our experience of posterolateral epidural supra-C2-root approach (PESCA) for biopsy of retro-odontoid lesions in one surgical session after occipitocervical fixation and decompression in a patient with CDS and massive brainstem compression.

Case Presentation

A 70-year-old woman presented to our department with a 4-week history of progressive walking impairment, neck pain, neck rigidity, fever, dizziness, slight palsy of the left hand, and multiple fall episodes. Magnetic resonance imaging (MRI) of the craniovertebral junction (CVJ) and cervical spine revealed a lesion of the odontoid process and the retro-odontoid region with mainly solid components, as well as small cystic components, and brainstem compression and displacement. In first step, fusion surgery of the CVJ C0–C4 was performed with occiptocervical decompression. After fusion and decompression the lower lateral part of the C1 arc and the lateral superior part of the left side of the C2 arc were removed. The entry point was located directly above the superior part of the C2 root. A biopsy of the lateral portions of the lesions was obtained by bioptic forceps under microscope guidance. Pathologic examination of the mass revealed deposition of birefringent crystals compatible with calcium pyrophosphate. In addition to the clinical symptoms (especially neck pain), the diagnosis of CDS was made. Non-steroidal inflammatory drugs (NSAIDs) and colchicine (and later magnesium) were started. At follow-up examination 6 months after surgery, an MRI scan of the cervical spine revealed regression of the pannus and the cyst with replacement of the brainstem, clinical improvement of walking, and increased strength of the left hand.

Conclusions

This study demonstrates that PESCA can be used to obtain tissue for pathological analysis in one surgical sitting after fusion and decompression and that fusion, decompression, and PESCA (in the same session) together with subsequent conservative management could be a good alternative for the treatment of CDS.

The selective odontoidectomy: endoscopic endonasal approach to the craniocervical junction

OBJECTIVE

The resection of the odontoid process via an extended endoscopic endonasal approach has been recently proposed as an alternative to the microscopic transoral method. We aimed to delineate a minimally invasive endoscopic transnasal odontoidectomy and to describe the endoscopic anatomy of the anterior craniovertebral junction (CVJ).

MATERIALS AND METHODS

The anterior CVJ of 14 fresh adult cadavers were selectively accessed via a binostril endoscopic endonasal approach using 0- and 30-degree endoscopes.

RESULTS

The nasopharynx was widely exposed without removing any of the turbinates and without performing a sphenoidotomy. Occipital condyles and lateral masses of the C1 vertebra have been exposed inferiorly at lateral margins of the exposure, in addition to the foramen lacerum, which came into view at the superolateral corner of the operative field. The anterior arch of C1 and the upper 1.5 cm of the odontoid process of C2 have been removed via a minimally invasive endoscopic transnasal approach in all dissections.

CONCLUSIONS

We propose the selective odontoidectomy as a minimally invasive method for the endoscopic endonasal removal of the odontoid process. By using this approach, turbinates and the sphenoid sinus remain unharmed. In addition, this approach may be used in exposing pathologies situated laterally at the anterior CVJ, such as the lateral masses of atlas and occipital condyles.

Advances in videoassisted anterior surgical approach to the craniovertebral junction

At the present time, an update to the classical microsurgical transoral decompression is supported by the most recent literature dealing with the introduction of the endoscopy in spine surgery. In this paper, we present all the reported experience on the surgical approaches to anterior cranioveretebral junction (CVJ) compressive pathology managed by endoscopy. Surgical strategies dealing with decompressive procedures by using an open access, microsurgical technique, neuronavigation and endoscopy are summarized.Endoscopy represents a useful complement to the standard microsurgical approach to the anterior CVJ. Endoscopy can be used via transnasal, transoral and transcervical routes; it facilitates visualisation and better decompression without the need for soft palate splitting, hard palate resection, or extended maxillotomy. Although neuronavigation enhances orientation within the surgical field, intraoperative fluoroscopy helps to recognize residual compression.Under normal anatomical conditions, there appear to be no surgical limitations for the endoscopically assisted transoral approach compared with the pure endonasal and transcervical endoscopic approaches.The endoscope has a clear role as "support" to the standard transoral microsurgical approach since 30° angulated endoscopy increases the surgical area exposed over the posterior pharyngeal wall and the extent of the clivus.

Anterior video-assisted approach to the craniovertebral junction: transnasal or transoral? A cadaver study

BACKGROUND

Endoscopy represents both an alternative and useful complement to the standard microsurgical approach to the anterior craniovertebral junction (CVJ). Nevertheless, few studies provide an experimental comparison between transnasal and transoral endoscopic control on CVJ. We compared the surgical exposition angle and the working channel volume of both the transnasal and transoral approaches in the cadaver.

METHODS

Eleven fresh non-perfused cadavers were studied. Transnasal and transoral linear and angled exposure of the CVJ were evaluated by means of X-ray and CT scan both in sagittal and lateral planes.

RESULTS

The transoral endoscopic surgical exposition was wider compared with the transnasal in anterior and lateral projections:(1)in the sagittal plane, both in vertical exposition (transnasal inferior to transoral from 5.89 % to 76.48 %, average 35.89 %) and in vertical surgical angle (from 22 % to 77.42 %, average 56.53 %); (2)in the coronal plane, both in coronal exposition (transnasal inferior to transoral from 50.77 % to 83.88 %, average 70.34 %) and in coronal surgical angle (from 65.58 % to 86.71 %, average 76.70 %). The sagittal surgical domain was found to spanning from the inferior third of the clivus to C3 with the transoral and from the middle third of the clivus to the nasopalatal line (NPL) with the transnasal approach. The overlapping surgical domain area was found to be the inferior third of the clivus.

CONCLUSIONS

The endoscope assisted transoral approach allows a better surgical control of the CVJ. It provides a better CVJ exposure, in sagittal and transverse planes, providing a larger working channel and an easier manoeuvrability. The transnasal approach is limited in caudal direction down to the NPL, otherwise the transoral approach is limited in the rostral direction with a maximum to the foramen magnum in normal specimen. In every individual case, pros and cons of the appropriate approach have to be taken into account as well as the choice of a combined transnasal and transoral approaches strategy.

Posterior realignment of irreducible atlantoaxial dislocation with C1-C2 screw and rod system: a technique of direct reduction and fixation

BACKGROUND CONTEXT

Treatment of chronic and irreducible atlantoaxial dislocation (AAD) with ventral compression is challenging for surgeons. The main procedures are occipitocervical/C1-C2 fusion after transoral odontoidectomy or release of the periodontoid tissues. These surgical procedures, which are performed simultaneously or intermittently, have many disadvantages that may discount their effectiveness. Therefore, a more effective way to achieve surgical reduction and to keep solid stability with only a single procedure is needed.

PURPOSE

We describe a technique to reduce chronic and irreducible AAD with C1 lateral mass and C2 pedicle screw and rod system.

STUDY DESIGN

This was a retrospective case series.

PATIENT SAMPLE

Our sample comprised 26 patients (9 men and 17 women) with irreducible AAD who ranged in age from 15 to 54 years (mean, 35 years).

OUTCOME MEASURES

Patients' neurologic status was evaluated with the Japanese Orthopedic Association (JOA) scale.

METHODS

Twenty-six symptomatic patients underwent posterior realignment and reduction through the C1 lateral mass and C2 pedicle screw and rod system. The proposed mechanism of reduction is that the implanted screws and rods between C1 and C2 acting as a lever system drew C1 backward and pushed C2 downward and forward after removing circumambient obstruction and scars and thoroughly releasing the facet joints. The preoperative and postoperative JOA score, the extent of reduction, and the conditions of C1-C2 bony fusion were examined.

RESULTS

No neurovascular injury occurred during surgery. Follow-up ranged from 6 to 40 months (mean 20.7 months). Radiographic evaluation showed that solid bony fusion was achieved in all patients, and that complete reduction was attained in 18 patients and partial reduction (>60% reduction) in 8 patients. The mean postoperative JOA score at last follow-up was 15.7, compared with the preoperative score of 12.1 (p<.01).

CONCLUSIONS

This C1-C2 screw and rod system provides reliable stability and sufficient reduction of the anatomic malalignment at the craniovertebral junction and meanwhile retains the mobility of atlanto-occipital joints in the treatment of chronic and irreducible AAD. Sophisticated skills, thorough release of the facet joints, and intraoperative protection of the vertebral artery are key points to accomplish this technique.