C1 anterior arch preservation in transnasal odontoidectomy using three-dimensional endoscope: A case report

Lesson learned in endoscopic endonasal dens resection for C1-C2 spinal cord decompression

PURPOSE

Endoscopic endonasal approach (EEA) is the safest and most effective technique for odontoidectomy. Nevertheless, this kind of approach is yet not largely widespread. The aim of this study is to share with the scientific community some tips and tricks with our ten-year-old learned experience in endoscopic endonasal odontoidectomy (EEO), which remains a challenging surgical approach.

MATERIAL AND METHODS

Our case series consists of twenty-one (10 males, 11 females; age range of 34-84 years) retrospectively analyzed patients with ventral spinal cord compression for non-reducible CVJ malformation, treated with EEA from July 2011 to March 2019.

RESULTS

The results have recently been reported in a previous paper. The only intraoperative complication observed was intraoperative cerebrospinal fluid (CSF) leak (9.5%), without any sign of post-operative CSF leak.

CONCLUSIONS

Considering our experience, EEO represents a valid and safe technique to decompress neural cervical structures. Despite its technical complexity, mainly due to the use of endoscope and the challenging surgical area, with this study we encourage the use of EEO displaying our experience-based surgical tips and tricks.

[Minimally invasive surgery for invaginated CII odontoid process]

Odontoidectomy is indicated for anterior compression of the brainstem by invaginated odontoid process. This procedure can currently be performed via transoral microsurgical and transnasal endoscopic access.

OBJECTIVE

To analyze the results of endoscopic transnasal odontoidectomy.

MATERIAL AND METHODS

We assessed treatment outcomes in 10 patients with anterior compression of the brainstem by invaginated odontoid process. All patients underwent endoscopic transnasal odontoidectomy.

RESULTS

Brainstem decompression was achieved in all cases.

CONCLUSION

Currently, endoscopic transnasal approach is gradually replacing the transoral one in some patients requiring anterior odontoidectomy. Analysis of literature data reflects the development of this technique taking into account various features of surgical treatment including optimization of dimensions of surgical field, attempts to perform C1-sparing surgeries and analysis of sufficient size of trepanation. Nasopalatine and nasoclival lines are used to select optimal access. Nevertheless, the choice of access depends on equipment of the hospital and surgical experience in most cases.

Biomechanical evaluation of the craniovertebral junction after odontoidectomy with anterior C1 arch preservation: A finite element study

OBJECTIVE

Odontoidectomy with preservation of the anterior C1 arch can be increasingly achieved by an endoscopic endonasal approach. It is controversial whether preservation of the anterior C1 arch after odontoidectomy can prevent instability of the craniovertebral junction （CVJ） and avoid posterior fixation. The aim of this research was to investigate the biomechanical effect of the preserved anterior C1 arch after odontoidectomy.

METHODS

A validated finite element model of a whole cervical spine (occipital bone to T1) was constructed to study the biomechanical changes due to traditional odontoidectomy (TO) and odontoidectomy with preservation of the anterior C1 arch (OPC1).

RESULTS

The greatest biomechanical changes in the cervical spine model after TO and OPC1 occurred at C0-C1 and C1-C2. At C0-C1 and C1-C2, the motion changes of the TO and OPC1 models had no significant difference in flexion, extension and lateral bending. Compared with the intact model, motion increases of the two surgical models were both extremely significant at C1-C2 in extension (128.2% vs. 128.1%) and lateral bending (178% vs. 156%). In axial rotation, the TO approach produced more motions than the OPC1 approach, especially at C1-C2(90.3° under TO approach, and 74.6° under OPC1 approach).

CONCLUSIONS

Preservation of the anterior C1 arch after odontoidectomy can preserve the axial rotational motion at C0-C1 and C1-C2, whereas the motions in extension and lateral bending continue to have an extremely abnormal increase at C1-C2. Thus, instability of the CVJ still exists, and posterior internal fixation may also be required after OPC1.

Craniovertebral junction chordomas: Case series and strategies to overcome the surgical challenge

Introduction:

Chordomas are rare and malignant primary bone tumors. Different strategies have been proposed for chordomas involving the craniovertebral junction (CVJ) compared to other locations. The impossibility to achieve en bloc excision, the impact on stability and the need for proper reconstruction make their surgical management challenging.

Objective:

The objective is to discuss surgical strategies in CVJ chordomas operated in a single-center during a 7 years' experience (2013-2019).

Methods:

Adult patients with CVJ chordoma were retrospectively analyzed. The clinical, radiological, pathological, and surgical data were discussed.

Results:

A total number of 8 patients was included (among a total number of 32 patients suffering from skull base chordoma). Seven patients underwent endoscopic endonasal approach (EEA), and posterior instrumentation was needed in three cases. Three explicative cases were reported: EEA for midline tumor involving lower clivus and upper cervical spine (case 1), EEA and complemental posterior approach for occurred occipitocervical instability (case 2), C2 chordoma which required aggressive bone removal and consequent implant positioning, focusing on surgical planning (timing and type of surgical stages, materials and customization of fixation system) (case 3).

Conclusion:

EEA could represent a safe route to avoid injuries to neurovascular structure in clival locations, while a combined approach could be considered when tumor spreads laterally. Tumor involvement or surgical procedures could give raise to CVJ instability with the need of complementary posterior instrumentation. Thus, a tailored preoperative planning should play a key role, especially when aggressive bone removal and implant positioning are needed.

Staged Repositioning in Endoscopic Endonasal Odontoidectomy Maximizes Decompression While Allowing Preservation of the C1 Anterior Arch: A Technical Note

BACKGROUND

Preservation of the anterior arch of C1 in endoscopic endonasal odontoidectomy has been proposed as an alternative to complete C1 arch resections, potentially affording less destabilization of the craniocervical junction. Nonetheless, this approach may limit the decompression achieved. In this case, intraoperative repositioning allowed maximal decompression while preserving the anterior arch of C1.

METHODS

A 79-year-old woman presented with suboccipital pain caused by an expansile and compressive mass centered on the dens. Notably, the mass occluded both vertebral arteries resulting in small cerebellar strokes. An endoscopic endonasal approach for diagnosis and decompression was performed followed by posterior fixation.

RESULTS

Given the significant compression, the patient was initially positioned in slight cervical extension. After rhinopharyngeal flap harvest, the top half of the anterior arch of C1 was resected, maintaining its structural integrity. The odontoidectomy was completed flush to the superior border of the reduced C1 arch. After an intraoperative computed tomography (CT) scan, performed in a neutral position, the patient was then repositioned with cervical flexion. This maneuver presented the residual odontoid above the C1 arch, but, given the partial removal of the dens, it did not result in any change in neuromonitoring. Further odontoid resection was then completed and follow-up CT scan revealed maximal dens removal, extending below the C1 anterior arch in neutral position.

CONCLUSIONS

In cases of odontoid/atlantoaxial pathology causing significant neural compression, staged intraoperative repositioning can safely maximize the odontoidectomy, while affording preservation of the structural integrity of the anterior arch of C1.

Endoscopic Endonasal Approach for Urgent Decompression of Craniovertebral Junction in Syringobulbia

BACKGROUND

Syringobulbia is an uncommon lesion that occurs in the central nervous system; it is often defined as a pathologic cavitation in the brainstem. The cases with partial blockage of the cerebrospinal fluid pathways at the level of the foramen magnum are more common and the most important group. The most common treatment of syringobulbia is craniovertebral decompression.

CASE DESCRIPTION

This paper reports a case of a symptomatic syringobulbia in which an urgent endoscopic endonasal approach to the craniovertebral junction (CVJ) was done to limit bulbo-medullary compression and rapid neurologic deterioration. A 69-year-old man was admitted to the hospital because of acute onset of dysphonia, dysphagia, imbalance, and vomiting. Magnetic resonance imaging revealed a cystic lesion in the brainstem, suggestive of a syringobulbia in Klippel Feil syndrome with CVJ stenosis.

CONCLUSIONS

This case report details the successful use of endoscopic endonasal anterior decompression to treat syringobulbia, and adds to the growing literature in support of the endonasal endoscopic approach as a safe and feasible means for decompressing the craniocervical junction, even in the setting of urgency. However, prudent patient selection, combined with sound clinical judgment, access to instrumentation, and intraoperative imaging cannot be overemphasized.

The Endonasal Endoscopic Approach to Pathologies of the Anterior Craniocervical Junction: Analytical Review of Cases Treated at Four European Neurosurgical Centres

Supported by preliminary anatomical and clinical studies exploring the feasibility and usefulness of approaching many ventral pathologies of the craniocervical junction (CCJ) using the endoscopic endonasal approach, four European centres have joined forces to accumulate and share their growing surgical experience of this advanced technique. By describing the steps that led to the development and continuous refinement of this approach to the CCJ, this article delves deeply into an analysis of the cases operated on since 2010 at these four institutions, and discusses in detail the operative nuances that so far have allowed achievement of successful outcomes with excellent perioperative patient comfort and satisfactory long-term quality of life.

The Endoscopic Endonasal Approach to Craniovertebral Junction Pathologies: Surgical Skills and Anatomical Study

INTRODUCTION

Surgical anterior decompression is the treatment of choice for symptomatic irreducible ventral craniovertebral junction (CVJ) compression. Along with the classic transoral approach, the endoscopic endonasal approach has evolved and is gaining growing success.

MATERIALS AND METHODS

In this work we discuss the surgical technique, give a complete step-by-step description of dissection of the craniovertebral junction and report a specific case of endoscopic endonasal odontoidectomy with use of a high-definition (HD) three-dimensional (3D) endoscope.

DISCUSSION

The extended endonasal approach exploits an anatomical corridor to the odontoid process, involving only a small incision in the nasopharynx and sparing palate integrity. The most important limitation of the technique is 2D visualization, which hinders correct recognition of anatomical structures.

CONCLUSION

The endoscopic endonasal route to the odontoid process has proven to be a feasible, safe and well-tolerated procedure. Anatomical study is very important for better understanding of the 3D anatomy of the CVJ and relation of critical neurovascular structures to specific bony and muscular landmarks.

Endonasal Endoscopic Odontoidectomy in Ventral Diseases of the Craniocervical Junction: Results of a Multicenter Experience

BACKGROUND

Over the past decades, supported by preliminary anatomic and clinical studies exploring its feasibility and safety, experience has increased of the use of the endoscopic endonasal approach (EEA) to ventral diseases at the craniocervical junction (CCJ).

METHODS

A multicenter study was carried out over a 4-year period of 14 patients managed by EEA odontoidectomy for CCJ diseases causing irreducible atlantoaxial dislocation. The surgical setup included an IGS system based on computed tomography and magnetic resonance images fusion, and 0° and 30° angled endoscopes with dedicated endoscopic tools.

RESULTS

Nine men and 5 women, with a mean age of 60.7 years, were included. The mean follow-up was 28.5 months; 9 patients had basilar impression, whereas 5 had a degenerative pannus. The quality of anterior decompression was excellent in all cases; nonetheless, a posterior stabilization was deemed necessary in 13 patients, and no external orthosis was used during the postoperative course. No tracheostomy or gastrostomy was required after surgery; no deaths, no new neurologic deficits/complications, and no postoperative cerebrospinal fluid leak were recorded. At follow-up, the neurologic status assessed with Frankel grade did not deteriorate in any of the patients but improved in 13 of them; and no new listhesis was shown on neuroradiologic follow-up.

CONCLUSIONS

The results show that EEA provides a direct surgical corridor to the CCJ, allowing an adequate decompression as with the more invasive transoral route. Morbidity is less than with a transoral approach, resulting in higher patient comfort and faster recovery.

Endoscopic Endonasal Approach for Craniovertebral Junction Pathologic Conditions: Myth and Truth in Clinical Series and Personal Experience

OBJECTIVE

For many years, the microsurgical transoral approach has been accepted as the gold standard for anterior decompressions of the craniovertebral junction (CVJ). The introduction of the endoscopic endonasal approach (EEA) has gained wide recognition and overwhelming support in recent years, including for diseases of the CVJ. The aim of this study was to critically analyze and discuss all cases of CVJ diseases approached by means of an EEA so far reported in the literature, including our institutional experience consisting of 6 consecutive patients.

METHODS

Six consecutive patients affected by CVJ disease underwent an EEA. Three patients had a tumor (2 chordomas and 1 myeloma) and 3 had impressio basilaris.

RESULTS

Five patients had an uncomplicated postoperative course and 1 developed an intraoperative cerebrospinal fluid leak and subsequent meningitis and died 5 weeks after surgery. A total of 107 patients (including our 6) affected by CVJ disease and treated with EEA have been reported so far. Among these patients, cerebrospinal fluid leak was reported in 13 (12.4%), transient velopharyngeal incompetence in 6 (5.6%), postoperative epistaxis in 2 (1.86%), and respiratory dysfunction requiring a tracheostomy in 2 (1.86%). In our extended institutional series of more than 20 consecutive anterior decompressions for CVJ diseases (including transoral and transnasal microsurgical approaches), the only fatal complication was associated with EEA.

CONCLUSIONS

On the basis of the reviewed literature and our personal experience, the reported increased safety of the EEA needs to be reassessed and discussed.

Endoscopic Endonasal Approach to the Odontoid Pathologies

BACKGROUND

Surgical anterior decompression represents the treatment of choice for symptomatic irreducible ventral craniovertebral junction (CVJ) compression. With the refinement of the endoscopic techniques, the endonasal route has been proposed as alternative to the classic transoral approach to CVJ. Some reports assess the effectiveness and safety of endoscopic endonasal approaches to CVJ pathologies.

MATERIALS AND METHODS

From July 2011 to February 2014, 12 patients with symptomatic nonreducible ventral spinal cord compression underwent purely 3-dimensional endoscopic endonasal odontoidectomy in our department. The surgical technique is described.

RESULTS

A good brainstem-medullary decompression was achieved in all patients. In 10 of 12 patients the endotracheal tube was removed just after the procedure with good recovery of the respiratory function. We report no cases of velopharyngeal insufficiency. In 5 of 12 patients the preservation of C1 anterior was achieved, without the need for posterior cervical fixation.

DISCUSSION AND CONCLUSIONS

Endoscopic endonasal odontoidectomy has proven to be safe and effective in selected patients. Soft and hard palate preservation dramatically reduces the risk of postoperative velopharyngeal insufficiency. Moreover, the endonasal endoscopic approach provides a direct access to the dens. Three-dimensional high-definition endoscope, laser, and ultrasound bony curettes revealed to be useful tools for this approach that, however, remains a demanding one.