Endoscope-assisted anterolateral approach to a recurrent cervical spinal chordoma

The Anterolateral Approach, Revisited for Benign Jugular Foramen Tumors With Predominant Extracranial Extension: Microsurgical Anatomy and Case Series (SevEN-012)

BACKGROUND AND OBJECTIVES

The anterolateral approach (ALA) enables access to the mid and lower clivus, jugular foramen (JF), craniocervical junction, and cervical spine with added anterior and lateral exposure than the extreme lateral and endoscopic endonasal approach, respectively. We describe the microsurgical anatomy of ALA with cadaveric specimens and report our clinical experience for benign JF tumors with predominant extracranial extension.

METHODS

A stepwise and detailed microsurgical neurovascular anatomy of ALA was explored with cadaveric specimens. Then, the clinical results of 7 consecutive patients who underwent ALA for benign JF tumors with predominant extracranial extension were analyzed.

RESULTS

A hockey stick skin incision is made along the superior nuchal line to the anterior edge of the sternocleidomastoid muscle (SCM). ALA involves layer-by-layer muscle dissection of SCM, splenius capitis, digastric, longissimus capitis, and superior oblique muscles. The accessory nerve runs beneath SCM and is found at the posterior edge of the digastric muscle. The internal jugular vein (IJV) is lateral to and at the level of the accessory nerve. The occipital artery passes over the longissimus capitis muscle and IJV and into the external carotid artery, which is lateral and superficial to IJV. The internal carotid artery (ICA) is more medial and deeper than external carotid artery and is in the carotid sheath with the vagus nerve and IJV. The hypoglossal and vagus nerves run along the lateral and medial side of ICA, respectively. Prehigh cervical carotid, prejugular, and retrojugular surgical corridors allow deep and extracranial access around JF. In the case series, gross and near-total resections were achieved in 6 (85.7%) patients without newly developed cranial nerve deficits.

CONCLUSION

ALA is a traditional and invaluable neurosurgical approach for benign JF tumors with predominant extracranial extension. The anatomic knowledge of ALA increases competency in adding anterior and lateral exposure of extracranial JF.

Key role of microsurgical dissections on cadaveric specimens in neurosurgical training: Setting up a new research anatomical laboratory and defining neuroanatomical milestones

Introduction

Neurosurgery is one of the most complex surgical disciplines where psychomotor skills and deep anatomical and neurological knowledge find their maximum expression. A long period of preparation is necessary to acquire a solid theoretical background and technical skills, improve manual dexterity and visuospatial ability, and try and refine surgical techniques. Moreover, both studying and surgical practice are necessary to deeply understand neuroanatomy, the relationships between structures, and the three-dimensional (3D) orientation that is the core of neurosurgeons' preparation. For all these reasons, a microsurgical neuroanatomy laboratory with human cadaveric specimens results in a unique and irreplaceable training tool that allows the reproduction of patients' positions, 3D anatomy, tissues' consistencies, and step-by-step surgical procedures almost identical to the real ones.

Methods

We describe our experience in setting up a new microsurgical neuroanatomy lab (IRCCS Neuromed, Pozzilli, Italy), focusing on the development of training activity programs and microsurgical milestones useful to train the next generation of surgeons. All the required materials and instruments were listed.

Results

Six competency levels were designed according to the year of residency, with training exercises and procedures defined for each competency level: (1) soft tissue dissections, bone drilling, and microsurgical suturing; (2) basic craniotomies and neurovascular anatomy; (3) white matter dissection; (4) skull base transcranial approaches; (5) endoscopic approaches; and (6) microanastomosis. A checklist with the milestones was provided.

Discussion

Microsurgical dissection of human cadaveric specimens is the optimal way to learn and train on neuroanatomy and neurosurgical procedures before performing them safely in the operating room. We provided a “neurosurgery booklet” with progressive milestones for neurosurgical residents. This step-by-step program may improve the quality of training and guarantee equal skill acquisition across countries. We believe that more efforts should be made to create new microsurgical laboratories, popularize the importance of body donation, and establish a network between universities and laboratories to introduce a compulsory operative training program.

“Endoscope-assisted Anterolateral Approach for a Craniovertebral Junction Chordoma”

Chordomas of craniovertebral junction represent a challenging pathology for neurosurgeons, due to their deep location, proximity with critical neurovascular structures and local aggressiveness. Several surgical options are available for these tumors: both endoscopic extended approaches and open approaches. We present the case of a 24 years old female with a craniovertebral junction chordoma with anterior and right lateral extension. For this case, an anterolateral approach with endoscopic assistance was chosen. Key surgical steps are presented. In the postoperative course the neurological symptoms improved and there were no complications. Unfortunately, she had an early recurrence of tumor two months later, prior the beginning of radiotherapy. After multidisciplinary consultation, we performed a second surgical removal and a posterior cervical spine arthrodesis. The anterolateral approach is a valuable option for craniovertebral junction chordomas with lateral extension and the endoscope assistance allowed to reach the narrowest and furthermost points. The patients must be referred to multidisciplinary skull base surgery centers and be addressed to early adjuvant radiation therapy.

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.