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

A Three-Step Submandibular Retropharyngeal Approach to the Craniovertebral Junction: Is Less Always More?

Background: Accessing the craniovertebral junction poses unique challenges due to its anatomical complexity and proximity to critical structures, such as the cord-brainstem junction, great vessels of the neck, cranial nerves, oropharynx, and rhinopharynx. Among the approaches that have been developed over the years, the submandibular retropharyngeal approach offers good antero-lateral access without the need of transgressing mucosal layers. In its traditional form, however, this approach involves multiple sequential steps and requires intricate dissection, extensive retraction, and meticulous maneuvering, which can increase operative time and produce approach-related morbidity. Methods: With this paper, we propose a simplified technique for a submandibular retropharyngeal approach involving only three surgical steps. The advantages and limitations of this technique are illustrated through three surgical cases of neoplastic and degenerative craniovertebral junction pathologies. Results: In two out of the three cases, our technique allowed for a wide exposure of the lesions that could be resected totally or sub-totally with good outcome. In one case with involvement of the clivus and the occipital condyle, the exposure was inadequate; a biopsy was obtained, and the lesion was subsequently resected via and endoscopic transmucosal approach. Conclusions: Our technique represents a significant simplification of the traditional submandibular retropharyngeal approach; with appropriate indication, it permits a fast, safe, and adequate exposure of craniovertebral junction pathologies.

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.

Os odontoideum associated with a retro-odontoid cyst treated with posterior C1-C3 fixation: A case report and literature review

Background

Os odontoideum is a rare abnormality of the upper cervical spine, and os odontoideum associated with a retro-odontoid cyst has been described as a marker of local instability.

Case description

This paper reports a case of a 52-year-old female patient who was diagnosed with os odontoideum associated with a retro-odontoid cyst. The patient underwent posterior C1-C3 fixation without surgical removal of the cyst. Magnetic resonance imaging (MRI) two days later revealed that the retro-odontoid cyst was still present and that there were no significant changes to it when compared with the preoperative MRI.

Conclusion

Retro-odontoid cysts associated with unstable os odontoideum can lead to symptomatic spinal cord compression. Posterior C1-C3 fixation can restore atlantoaxial stability by allowing the gradual resorption of the cyst and ensuring spinal cord decompression. Fixation can also avoid the surgical risk associated with a high-riding vertebral artery.

Virtual reality surgical planning for endoscopic endonasal approaches to the craniovertebral junction

PURPOSE

To demonstrate the utility of virtual reality (VR) for preoperative surgical planning of endoscopic endonasal craniovertebral junction (CVJ) surgery.

MATERIALS AND METHODS

Five patients who had undergone endoscopic endonasal surgery of the craniovertebral junction with preoperative virtual reality surgical planning were identified and described.

RESULTS

The anterior approach to the CVJ has been traditionally accomplished transorally. However, recently the transnasal endoscopic approach to this location has been described. Multiple anatomical studies have been conducted using the nasopalatine, nasoaxial, and rhinopalatine lines (NPL, NAxL, RPL) in an attempt to preoperatively delineate the inferior limits of endoscopic dissection. The use of advanced surgical simulation using immersive virtual reality is an innovative approach for analyzing CVJ anatomy and developing a surgical plan. VR simulation through the use of interactive and highly accurate patient specific models allows for the creation of three-dimensional (3D) digital reconstructions via the fusion of CT and MRI studies. Incorporation of simulation technology has been shown to increase surgeon proficiency while simultaneously decreasing complication rates. The described case series demonstrates the novel utility of VR planning for designing the endoscopic surgical approach to the CVJ.

CONCLUSIONS

VR technology allows for the creation of anatomically accurate 3D models that can be used for preoperative planning of endoscopic endonasal surgery. Such models help in the development of safe surgical plans by predicting inferior and lateral planes of dissection and assisting in the identification of critical structures.

Multidisciplinary approach to the craniovertebral junction. Historical insights, current and future perspectives in the neurosurgical and otorhinolaryngological alliance

Historically considered as a nobody’s land, craniovertebral junction (CVJ) surgery or specialty recently gained high consideration as symbol of challenging surgery as well as selective top level qualifying surgery. The alliance between Neurosurgeons and Otorhinolaringologists has become stronger in the time. CVJ has unique anatomical bone and neurovascular structures architecture. It not only separates from the subaxial cervical spine but it also provides a special cranial flexion, extension, and axial rotation pattern. Stability is provided by a complex combination of osseous and ligamentous supports which allows a large degree of motion. The perfect knowledge of CVJ anatomy and physiology allows to better understand surgical procedures of the occiput, atlas and axis and the specific diseases that affect the region. Although many years passed since the beginning of this pioneering surgery, managing lesions situated in the anterior aspect of the CVJ still remains a challenging neurosurgical problem. Many studies are available in the literature so far aiming to examine the microsurgical anatomy of both the anterior and posterior extradural and intradural aspects of the CVJ as well as the differences in all the possible surgical exposures obtained by 360° approach philosophy. Herein we provide a short but quite complete at glance tour across the personal experience and publications and the more recent literature available in order to highlight where this alliance between Neurosurgeon and Otorhinolaringologist is mandatory, strongly advisable or unnecessary.

Inflammatory Response to Spinal Cord Injury and Its Treatment

Spinal cord injury (SCI), as one of the intractable diseases in clinical medicine, affects thousands of human beings, and the pathologic changes after injury have been a hot spot for exploration in clinical medicine. With the development of new treatments, the survival of patients has shown an increasing trend; however, the inflammatory response after injury has not yet been effectively controlled. SCI is divided into primary injury and secondary injury according to the time of injury and pathophysiologic changes. Primary injury occurs immediately and the damage to the injury site is irreversible; however, secondary injury occurs after primary injury and involves pathologic changes at the cellular and molecular levels, which are reversible. Thus, the inflammatory response from secondary injuries has become the main direction of research. In recent years, a complex pathophysiologic mechanism has gradually been unveiled, which has been followed by an upgrade of treatment methods. This article describes the mechanisms of the inflammatory response after SCI and the mainstream treatment modalities. Also, neuroprotective agents and nerve regeneration agent agents are commonly used in the treatment of SCI; the therapeutic mechanism and classification of these agents are reviewed.

Anterior cervical osteophytes causing dysphagia: Choice of the approach and surgical problems

Background

Anterior cervical osteophytes (ACOs) may rarely cause dysphagia, dysphonia, and dyspnea. Symptomatic ACOs are most commonly located between C3 and C7, whereas those at higher cervical (C1-C2) levels are rarer. We report a case series of 4 patients and discuss the best surgical approach according to the ostheophyte location and size, mainly for those located at C1-C2, and the related surgical problems.

Materials and Methods

Four patients (two males and two females) aged from 57 to 72 years were operated on for ACOs, causing variable dysphagia (and dyspnea with respiratory arrest in one). Three patients with osteophytes between C3 and C5 were approached through antero-lateral cervical approach, and one with a large osteophyte between C1 and C3-C4 level underwent a two-stage transcervical and transoral approach. All had significant postoperative improvement of dysphagia.

Results

The patient operated on though the transoral approach experienced postoperative flogosis of the prevertebral tissues and occipital muscles and thrombosis of the right jugular vein and transverse-sigmoid sinuses (Lemierre syndrome).

Conclusion

The transoral approach is the best surgical route to resect C1 and C2 ACOs, whereas the endoscopic endonasal approach is not indicated. The anterior transcervical approach is easier to resect osteophytes at C3, as well as those located below C3. A combined transoral and anterior cervical approach may be necessary for multilevel osteophytes.

Surgical Management of Skull Base and Spine Chordomas

OPINION STATEMENT

Management of chordoma along the cranial-spinal axis is a major challenge for both skull base and spinal surgeons. Although chordoma remains a rare tumor, occurring in approximately 1 per 1 million individuals, its treatment poses several challenges. These tumors are generally poorly responsive to radiation and chemotherapy, leading to surgical resection as the mainstay of treatment. Due to anatomic constraints and unique challenges associated with each primary site of disease, gross total resection is often not feasible and is associated with high rates of morbidity. Additionally, chordoma is associated with high rates of recurrence due to the tumor's aggressive biologic features, and postoperative radiation is increasingly incorporated as a treatment option for these patients. Despite these challenges, modern-day surgical techniques in both skull base and spinal surgery have facilitated improved patient outcomes. For example, endoscopic endonasal techniques have become the mainstay in resection of skull base chordomas, improving the ability to achieve gross total resection, while reducing associated morbidity of open transfacial techniques. Resection of spinal chordomas has been facilitated by emerging techniques in preoperative imaging, intraoperative navigation, spinal reconstruction, and radiotherapy. Taken collectively, the treatment of chordoma affecting the skull base and spinal requires a multidisciplinary team of surgeons, radiation oncologists, and medical oncologists who specialize in the treatment of this challenging disease.

A 360° Approach to the Craniovertebral Junction in a Cadaveric Laboratory Setting: Historical Insights, Current, and Future Perspectives in a Comparative Study

BACKGROUND

We herein outline the experience matured in our equipped Cranio-Vertebral Junction Laboratory for anatomic dissection.

METHODS

An extreme lateral approach (ELA) was performed on 4 fresh cadavers and submandibular approach was performed on 5. An endoscope and navigation-assisted far lateral approach (FLA) was performed in 5 injected specimens. In these specimens, a transoral approach was also performed, as well as a neuronavigation-assisted comparison between transoral and transnasal explorable distances.

RESULTS

As calculated with neuronavigation, statistically significant differences both in the explored craniocaudal (P = 0.003) and lateral (P = 0.008) distances were observed between the transoral approach and endoscopic endonasal approach. In FLA, neuronavigation facilitated identification and partial removal of the occipital condyle; in one case, during endoscopic intradural exploration, tearing of the emerging roots of the 11th cranial nerve occurred. In ELA, the site where the accessory nerve pierces into the sternocleidomastoid muscle was found at a distance from the tip of the mastoid between 3 and 4 cm.

CONCLUSIONS

During dissections, as in the clinical setting, endoscope and image guidance give the surgeon a constant orientation, increasing the accuracy and the safety of the approach. Nonetheless, the encumbrance of the endoscope could represent a limit in deep and narrow corridors as those running across the craniovertebral junction, especially in "oblique" FLA and ELA, in which the surgical target is often hidden by a delicate tangle of nerves and vessels. Its use appears more suitable and safer in "straight" approaches as transoral and transnasal in which there are no neurovascular structures interposed.

Navigation-Guided Measurement of the Inferior Limit Through the Endonasal Route to the Craniovertebral Junction

BACKGROUND

The endoscopic endonasal approach (EEA) has been accepted as an alternative option for diseases at the craniovertebral junction. However, the inferior destination through the endoscopic endonasal approach is anatomically higher than that of the transoral approach. Therefore, preoperative assessment of accessibility is mandatory for appropriate selection of indication. Using a navigation system, we examined the inferior limit through the endonasal route and evaluated the relationships between surrounding anatomicl structures and the lowest point.

METHODS

This study included patients who underwent endoscopic transsphenoidal surgery for intrasellar lesions at our hospital (N = 23). At the start of surgery, the lowest point (target point [TP]) was marked with a straight probe under guidance of the navigation system. We measured 4 parameters on preoperative computed tomography: nasal length, hard palate length, anterior-posterior diameter of the nasopharynx, and nasopalatine angle. Patients were classified into groups depending on whether the TP was at or above (group A) or below (group B) the hard palatine line.

RESULTS

TPs were above the hard palatine line in 15 patients (group A) and below the hard palatine line in 8 patients (group B). No TPs reached the nasopalatine line. Nasal length (P = 0.03) and nasopalatine angle (P = 0.01) were larger in group B than in group A. There were no significant differences in anterior-posterior diameter of the nasopharynx or hard palate length.

CONCLUSIONS

The hard palatine line is a reliable parameter for assessing the inferior limit of the endoscopic endonasal approach. Nostril size affects accessibility with surgical instruments.

[Anatomy of anterior craniovertebral junction in endoscopic transnasal approach]

Modern achievements in endoscopic technologies ensure extending the indications for endoscopic transnasal approach in skull base surgery. Knowledge on topographic anatomy of craniovertebral junction is a prerequisite for surgical interventions in this area. Transnasal endoscopic surgery of craniovertebral junction is a relatively new field. Therefore, this manuscript and similar anatomical studies are extremely important for neurosurgeons.

Atlantoaxial instability treated with free-hand C1-C2 fusion in a child with Morquio syndrome

Mucopolysaccharidosis type IVA, also known as Morquio syndrome, is an autosomal recessive lysosomal storage disease. Skeletal dysplasia with short stature, dysplastic-hypoplastic dens (os odontoideum), ligamentous hyperlaxity, and C1-C2 instability are characteristic features. Most patients with Morquio syndrome present with compressive myelopathy at a young age as a result of a combination of C1-C2 instability and extradural soft tissue thickening; treatment generally consists of anterior decompression with occipito-cervical fusion and external orthosis. In this report, we describe the successful treatment of a young child using posterior C1-C2 fusion alone with a free-hand technique. A 3-year-old boy presented at our hospital with a 5-month history of progressive quadriparesis. A whole-body skeletal survey showed skeletal dysplasia with hypoplasia, thoracolumbar kyphosis, and atlantoaxial subluxation. Preoperative cervical imaging showed compressive myelopathy at C1-C2 and atlantoaxial subluxation. C1-C2 fixation and decompression were performed successfully. After the operation, the patient had improved strength and was able to walk independently 8 months postoperatively. Establishment of stability via C1-C2 fusion is challenging in patients with genetic disorders characterized by skeletal dysplasia because of these young patients' small bone size and deficient bone quality. In this unique case, the treatment consisted solely of C1-C2 fusion with a free-hand technique. This case report presents a new approach in the treatment of atlantoaxial instability in Morquio syndrome.

Hybrid antero-lateral transcondylar approach to the clivus: a laboratory investigation and case illustration

BACKGROUND

Surgical treatment of lesions involving the ventral craniovertebral junction (CVJ) and the lower clivus, traditionally involved complex lateral or transoral approaches to the skull base. However, mid or upper clivus involvement requires more extensive lateral approaches. Recently, the endoscopic endonasal approach (EEA) has become the standard for upper CVJ lesions and medial clival, and a valuable alternative for those tumors extending in its upper third as well as laterally. However, the EEA is associated with an increased risk of post-operative CSF leakage and infection when the tumor is characterized by an intradural extension. Furthermore, whenever the tumor has significant lateral and/or inferior extension below the odontoid process, the chances for a complete resection decrease.

METHOD

To analyze the extent of exposure of a hybrid microscopic-endoscopic transcondylar antero-lateral approach to the CVJ and clival region, and to verify its effectiveness in terms of mid and upper clival access. Five silicone-injected cadaver heads were used. Following a standard antero-lateral approach, condylectomy and jugular tubercle drilling were performed, after which angled endoscopes were utilized to extend the bone resection to the clivus. A volumetric assessment of the amount of clival removal was carried out. A case of CVJ chordoma operated through this approach is presented.

RESULTS

The hybrid antero-lateral transcondylar approach provides adequate exposure of the ventral CVJ, up to the dorsum sellae and the sphenoid sinus, the contralateral petrous apex, and the contralateral paraclival internal carotid artery (ICA). Approximately 60% of the total clival volume can be removed with this approach. The main limitation is the limited visualization of the ipsilateral paraclival ICA and petrous apex.

CONCLUSION

The hybrid antero-lateral transcondylar approach is a valuable surgical option for CVJ tumor extending from C2 to the mid and upper clivus.

Atlantoaxial dislocation due to os odontoideum in patients with Down's syndrome: literature review and case reports

PURPOSE

To clarify etiology, clinical features, and diagnostic and treatment options of atlantoaxial dislocation (AAD) due to os odontoideum (OsO) in patients with Down's syndrome (DS).

METHODS

We described and analyzed three clinical cases of AAD due to OsO in DS patients and reviewed descriptions of similar cases in the scientific sources.

RESULTS

According to literature review, more than 80% of DS patients with odontoid ossicles had atlantoaxial instability (AAI). AAI in DS patients with OsO is more often manifested in childhood and adolescence, rarely in adults when ligament relaxation is reduced. Some patients had acute clinical manifestation after a minor trauma without any precursors; in some of the cases, neurological deterioration increased during several years. We found that the earlier surgical treatment of AAD due to OsO in DS patients carries the higher recovery potential.

CONCLUSIONS

Most patients with DS and OsO had AAI. The method of appropriate treatment in such cases is a posterior screw fixation. Preoperative halo traction and posterior fusion have proved to be a very useful tool in the treatment of AAD due to OsO in DS patients. Even if irreducibility of the AAD established preoperatively, it should not be an absolute indication for anterior decompression. In such cases, an attempt to reduce the AAD should be made under general anesthesia during posterior fixation.

Anatomical Aspects of the Transnasal Endoscopic Access to the Craniovertebral Junction

OBJECTIVE

Interest in endoscopic transnasal access has increased with continued technological advances in endoscopic technology. The goals of this study were to review the normal anatomy in transnasal endoscopic neurosurgery and outline the anatomical basis for an expanded surgical approach. Defining anatomical aspects of surgical endoscopy helps guide the surgeon by defining normal anatomy of the access vector.

METHODS

This anatomic study was conducted on 15 adult male cadaver specimens using various microsurgical tools and endoscopic instruments and 1 intraoperative case. The vasculature was injected with colored silicone to aid visualization. Different transnasal approach techniques were used, with angles of endoscope access at 0°, 30°, 45°, and 70° accordingly for extensive anatomical mapping.

RESULTS

The proximity of critical structures is different in each approach degree. A full understanding of the possible structures to be met during transnasal access is described. As a result of the study, anatomical aspects and important structures were outlined, and a surgical protocol was defined for minimal risk access in respect to normal anatomy of the area.

CONCLUSIONS

Thorough knowledge of topographic anatomy of the craniovertebral junction is required for performing minimal-risk surgical intervention in this region. It is important to know all anatomical aspects of the transnasal approach in order to reduce the risk of damage to vital structures. Transnasal endoscopic surgery of the craniovertebral junction is a relatively new direction in neurosurgery; therefore, anatomical studies such as the one described in this article are extremely important for the development of this access method.

Transoral Approach to the Craniovertebral Junction: A Neuronavigated Cadaver Study

More than 100 years after the first description by Kanavel of a transoral-transpharyngeal approach to remove a bullet impacted between the atlas and the clivus [1], the transoral approach (TOA) still represents the 'gold standard' for surgical treatment of a variety of conditions resulting in anterior craniocervical compression and myelopathy [2, 3]. Nevertheless, some concerns-such as the need for a temporary tracheostomy and a postoperative nasogastric tube, and the increased risk of infection resulting from possible bacterial contamination and nasopharyngeal incompetence [4-6]-led to the introduction of the endoscopic endonasal approach (EEA) by Kassam et al. [7] in 2005. Although this approach, which was conceived to overcome those surgical complications, soon gained wide attention, its clear predominance over the TOA in the treatment of craniovertebral junction (CVJ) pathologies is still a matter of debate [3]. In recent years, several papers have reported anatomical studies and surgical experience with the EEA, targeting different areas of the midline skull base, from the olfactory groove to the CVJ [8-19]. Starting from these preliminary experiences, further anatomical studies have defined the theoretical (radiological) and practical (surgical) craniocaudal limits of the endonasal route [20-25]. Our group has done the same for the TOA [26, 27] and compared the reliability of the radiological and surgical lines of the two different approaches. Very recently, a cadaver study, with the aid of neuronavigation, tried to define the upper and lower limits of the endoscopic TOA [28].

Why the Craniovertebral Junction?

The craniovertebral junction (CVJ) has unique anatomical bone and neurovascular structure architecture. It not only separates the skull base from the subaxial cervical spine but also provides a special cranial flexion, extension and axial rotation pattern. Stability is provided by a complex combination of osseous and ligamentous supports, which allow a large degree of motion. Perfect knowledge of CVJ anatomy and physiology allows us to better understand instrumentation procedures of the occiput, atlas and axis, and the specific diseases that affect the region. Therefore, a review of the vascular, ligamentous and bony anatomy of the region, in relation to all possible surgical approaches to this anatomically unique segment of the cervical spine, appears to be absolutely mandatory in order to preview and to overcome possible anatomy-related complications of CVJ surgery; moreover, knowledge of the basic principles of instrumentation and of the kinematics of the region, since they interact with the anatomy, seems to be strategic in preoperative planning.Historically considered a no man's land, CVJ surgery, or the CVJ specialty, has recently attracted strong consideration as a symbol of challenging surgery as well as selective top-level qualifying surgery.Although many years have passed since the beginning of this pioneering surgery, managing lesions situated in the anterior aspect of the CVJ still remains a challenging neurosurgical problem. Many studies are available in the literature, aiming to examine the microsurgical anatomy of both the anterior and posterior extradural and intradural aspects of the CVJ, as well as the differences in all possible surgical exposures obtained by the 360° approach philosophy. In this paper the author provides a short but quite complete at-a-glance tour of personal experience and publications and the more recent literature available.

Transoral Versus Transnasal Approach for Craniovertebral Junction Pathologies: Which Route Is Better?

BACKGROUND

Several pathologies that affect the craniovertebral junction (CVJ) can be treated by means of a microsurgical transoral approach (TOA) or, alternatively, with an endoscopic endonasal approach (EEA), which is potentially able to overcome some complications associated with the former approach. In this paper, after discussing updates in the recent literature, to which we add our own surgical experience, we critically analyse these procedures with the aim of demonstrating that the TOA still deserves to be considered a viable alternative and that, in selected cases, it can even be considered superior to the EEA.

METHODS

Our experience involves 25 anterior procedures in 24 paediatric and adult patients (18 TOA and seven EEA). The TOA group (13 male and five female patients) encompassed three tumours, three rheumatoid arthritis cases, one condylus tertius, three basilar invaginations, four impressio basilaris cases, one developmental anomaly of C0-C1, one os odontoideum, one posttraumatic C1-C2 compression and one C2 fracture. The EEA group (three male and four female patients, median age 39 years, operated on over a 7-year period) comprised four tumours, two impressio basilaris cases and one case of impressio basilaris with platybasia.

RESULTS

In the TOA group, all but one patient were discharged after posterior procedures within 2 weeks and improved or remained unchanged after surgery and during the follow-up period. No major complications occurred in the TOA group. In the EEA group, two patients who developed a cerebrospinal fluid (CSF) infection died, one from disease progression and the other from myocardial infarction.

CONCLUSION

Our data, in agreement with those from previous reports on other series, suggest that no clear superiority of the EEA over the endoscopic TOA can be postulated so far; in fact, the EEA can produce complications similar to those observed with the TOA in CVJ surgery.

Transoral Versus Transnasal Approach for Craniovertebral Junction Pathologies: Never Say Never

OBJECTIVE

For many years, the microsurgical transoral approach (TOA) has been accepted as the "gold standard" for the surgical treatment of a variety of congenital, developmental, and acquired pathologies affecting the craniovertebral junction. In the present study, we try to investigate both experimental and clinical fronts of such a challenging surgery, starting from the updated literature experience. TOA is actually presented as an "old-fashioned" surgical technique dealing with possible bacterial contamination, the need of postoperative nose gastric tube feeding for a week, the possible nasopharyngeal incompetence, and the postoperative tongue swelling. Otherwise, the endoscopic endonasal approach (EEA) appears strongly supported by the modern literature as the true "minimally invasive" procedure.

METHODS

Our clinical experience deals with 23 anterior procedures in paediatric and adult patients (17 TOA and 6 EEA). We further report on our experimental cadaver laboratory study of 12 subjects.

RESULTS

All the patients of TOA group but one were discharged after posterior procedures within two weeks and improved or remained unchanged after surgery and during the follow-up. No mayor complications occurred in TOA group. In EEA group two patients died for cerebrospinal fluid infection, for disease progression and for heart attack.

CONCLUSION

Our and other available data suggest that no clear superiority of EEA over endoscopic TOA can be assessed so far; on the other hand, EEA can produce complications similar to TOA in craniovertebral junction surgery.

Walk the Line. The Surgical Highways to the Craniovertebral Junction in Endoscopic Approaches: A Historical Perspective

BACKGROUND

We compiled a comprehensive literature review on the anatomic and clinical results of endoscopic approaches to the craniocervical junction (CVJ) to better contribute to identify the best strategy.

METHODS

An updated literature review was performed in the PubMed, OVID, and Google Scholar medical databases, using the terms "Craniovertebral junction," "Transoral approach," "Transnasal approach," "Transcervical approach," "Endoscopic endonasal approach," "Endoscopic transoral approach," "Endoscopic transcervical approach." Clinical series, anatomic studies, and comparative studies were reviewed.

RESULTS

Pure endonasal and cervical endoscopic approaches still have some disadvantages, including the learning curve and the deeper surgical field. Endoscopically assisted transoral surgery with 30° endoscopes represents an emerging option to standard microsurgical techniques for transoral approaches to the anterior CVJ. This approach should be considered as complementary rather than an alternative to the traditional microsurgical transoral-transpharyngeal approach.

CONCLUSIONS

The transoral approach with sparing of the soft palate still remains the gold standard compared with the pure transnasal and transcervical approaches because of the wider working channel provided by the former technique. The transnasal endoscopic approach alone appears to be superior when the CVJ lesion exceeds the upper limit of the inferior third of the clivus.