Endoscopic image-guided transcervical odontoidectomy: outcomes of 15 patients with basilar invagination

Clinical effect and prognosis of transoral or endoscope-assisted transoral release for irreducible atlantoaxial dislocation: A retrospective cohort study

Background

The clinical applications of endoscope-assisted transoral release for irreducible atlantoaxial dislocations are limited. This study aimed to investigate the clinical effect and prognostic factors of traditional and endoscope-assisted transoral release, as well as posterior reduction and fixation, in treating irreducible atlantoaxial dislocations.

Materials and methods

We conducted a retrospective study on 59 patients with irreducible atlantoaxial dislocation who underwent either traditional or endoscope-assisted transoral release, posterior fixation, and fusion between January 2018 and January 2023. Various data, including surgical time, blood loss, drainage volume, oral intake, hospital stay, complications, and neurological status (assessed by the Japanese Orthopedic Association [JOA] score and Oswestry Disability Index [ODI]), were recorded. Imaging parameters such as the atlantodontoid interval (ADI), space available for the cord (SAC), and cervicomedullary angle (CMA) were analyzed and compared. In addition, the correlation between ODI, JOA and patient age, course of disease, preoperative ADI, SAC and CMA were analyzed.

Results

No significant differences were observed in age, sex, BMI, preoperative ADI, preoperative SAC, or preoperative CMA. All patients achieved excellent reduction with no significant differences between the two groups. Patients in the endoscopic group experienced significantly reduced blood loss, earlier oral intake, and shorter hospital stays compared to those in the open group (P < 0.05). The ODI and JOA scores improved significantly in both groups at 1, 6, 12, 18, and 24 months postoperatively (P < 0.05). Postoperative ADI, SAC, and CMA values in both groups were significantly better than preoperative values (P < 0.001). The patient age, course of disease and the preoperative ADI were negatively correlated with the postoperative ODI and the JOA improvement ratio (P < 0.01), and the preoperative SAC and preoperative CMA had positive correlations with the postoperative ODI and the JOA improvement ratio (P < 0.01) at 6, 12 and 24 months postoperatively.

Conclusion

Patient age, course of disease, preoperative ADI, SAC and CMA are correlated with the operative prognosis of irreducible atlantoaxial dislocation. The endoscope-assisted transoral approach, compared to the traditional transoral approach, is minimally invasive, resulting in less operative blood loss, earlier oral intake and a shorter length of hospital stay, which could be offered as an alternative for irreducible atlantoaxial dislocation.

Release, reduction, and fixation of one-stage posterior approach for basilar invagination with irreducible atlantoaxial dislocation

PURPOSE

We evaluate the efficacy, safety and indications of single stage posterior release, reduction, and fixation of basilar invagination (BI) with irreducible atlantoaxial dislocation (IAAD).

MATERIALS AND METHODS

Seventeen patients with BI and IAAD consecutively underwent one-stage release, reduction, and fixation by a posterior approach from July 2000 to June 2015 were followed up for at least 12 months. There were 8 males. Mean age was 56 35.2 ± 13.8 years (range 12-56). The clinical symptoms and signs of the patients were recorded. Pre- and postoperative imaging examinations were performed. Neurological function was assessed using the Japanese Orthopedic Association (JOA) and Ranawat scores.

RESULTS

Average follow-up time was 47.4 months (12-97 months). The JOA score increased from preoperative 4-10 (8.06 ± 2.52) to postoperative 13-16 (15.20 ± 0.62). The preoperative Chamberlain line, McRae line, Wackenheim line, atlantodens interval, and cervico medullary angle were 12.52 ± 5.17 mm, 6.59 ± 3.04 mm, 6.96 ± 4.32 mm, 9.88 ± 1.93 mm, and 115.35 ± 12.40°, respectively. The postoperative values were 2.0 ± 3.67 mm, -3.06 ± 1.85 mm, -1.76 ± 2.88 mm, 1.17 ± 1.18 mm, and 136.76 ± 11.44°, respectively.

CONCLUSION

One-stage release, reduction, and fixation for patients with BI and IAAD through a posterior approach is safe and efficient.

Transcervical, retropharyngeal odontoidectomy - Anatomical considerations

Context

Anterior craniocervical junction lesions have always been a challenge for neurosurgeons. Presenting with lower cranial nerve dysfunction and symptoms of brainstem compression, decompression is often required. While posterior approaches offer indirect ventral brainstem decompression, direct decompression via odontoidectomy is necessary when they fail. The transoral and endoscopic endonasal approaches have been explored but come with their own limitations and risks. A novel retropharyngeal approach to the cervical spine has shown promising results with reduced complications.

Aims

This study aims to explore the feasibility and potential advantages of the anterior retropharyngeal approach for accessing the odontoid process.

Methods and Surgical Technique

To investigate the anatomical aspects of the anterior retropharyngeal approach, a paramedian skin incision was performed below the submandibular gland on two cadaveric specimens. The subcutaneous tissue followed by the platysma is dissected, and the superficial fascial layer is opened. The plane between the vascular sheath laterally and the pharyngeal structures medially is entered below the branching point of the facial vein and internal jugular vein. After reaching the prevertebral plane, further dissection cranially is done in a blunt fashion below the superior pharyngeal nerve and artery. Various anatomical aspects were highlighted during this approach.

Results

The anterior, submandibular retropharyngeal approach to the cervical spine was performed successfully on two cadavers highlighting relevant anatomical structures, including the carotid artery and the glossopharyngeal, hypoglossal, and vagus nerves. This approach offered wide exposure, avoidance of oropharyngeal contamination, and potential benefit in repairing cerebrospinal fluid fistulas.

Conclusions

For accessing the craniocervical junction, the anterior retropharyngeal approach is a viable technique that offers many advantages. However, when employing this approach, surgeons must have adequate anatomical knowledge and technical proficiency to ensure better outcomes. Further studies are needed to enhance our anatomical variations understanding and reduce intraoperative risks.

Advances, Challenges, and Future Directions in the Management of Craniovertebral Junction Pathologies

In this third article in a 3-article series on the craniocervical junction, we define the terms "basilar impression," "cranial settling," "basilar invagination," and "platybasia," noting that these terms are often used interchangeably but represent distinct entities. We then provide examples that represent these pathologies and treatment paradigms. Finally, we discuss the challenges and future direction in the craniovertebral junction surgery space.

Anatomical Description and Literature Review of the Endoscopic Endonasal Transclival Transodontoid Approach Combined with Endoscopic Transoral Decompression to the Anterior Craniovertebral Junction: A New Strategy

OBJECTIVE

To describe and evaluate the steps required to perform a combined endoscopic endonasal/transoral transclival transodontoid approach for anterior decompression of the craniovertebral junction.

METHODS

The endoscopic endonasal transclival transodontoid approach combined with endoscopic transoral decompression was performed on 4 cadaveric specimens. Evaluation of this combined technique; a review of the literature; and the nuances, advantages, and pitfalls are reported.

RESULTS

Adequate wide anterior decompression was achieved in all specimens. This combined approach allowed the preservation of the anterior arch of C1 without injuring the eustachian tube anatomy and avoiding internal carotid artery manipulation.

CONCLUSIONS

Mastery of both techniques allows for a safe and comfortable surgical corridor. The transoral and transnasal approaches should not be considered as either/or techniques, but rather as a complement to each other. However, as with all new or developing techniques, there is a steep learning curve, which requires ample training in the skull base laboratory.

An Approach to Managing Disorders Affecting the Craniovertebral Junction

The craniovertebral junction (CVJ), or the "first junction," can be affected by a variety of pathological states. Some of these conditions could represent a gray area in that they can be treated by general neurosurgeons or such specialists as skull base or spinal surgeons. However, some conditions are best managed with a multidisciplinary approach. The importance of in-depth knowledge of the anatomy and biomechanics of this junction cannot be overemphasized. Identifying what represents clinical stability or instability is key to successful diagnosis and, hence, treatment. In this report, the second in a 3-article series, we describe our approach to managing CVJ pathologies in a case-based fashion to illustrate key concepts.

Radiological assessment and surgical management of cervical spine involvement in patients with rheumatoid arthritis

The purpose of the present systematic review was to describe the diagnostic evaluation of rheumatoid arthritis in the cervical spine to provide a better understanding of the indications and options of surgical intervention. We performed a literature review of Pub-med, Embase, and Scopus database. Upon implementing specific inclusion and exclusion criteria, all eligible articles were identified. A total of 1878 patients with Rheumatoid Arthritis (RA) were evaluated for cervical spine involvement with plain radiographs. Atlantoaxial subluxation (AAS) ranged from 16.4 to 95.7% in plain radiographs while sub-axial subluxation ranged from 10 to 43.6% of cases. Anterior atlantodental interval (AADI) was found to between 2.5 mm and 4.61 mm in neutral and flexion position respectively, while Posterior Atlantodental Interval (PADI) was between 20.4 and 24.92 mm. 660 patients with RA had undergone an MRI. A pannus diagnosis ranged from 13.33 to 85.36% while spinal cord compression was reported in 0-13% of cases. When it comes to surgical outcomes, Atlanto-axial joint (AAJ) fusion success rates ranged from 45.16 to 100% of cases. Furthermore, the incidence of postoperative subluxation ranged from 0 to 77.7%. With regards to AADI it is evident that its value decreased in all studies. Furthermore, an improvement in Ranawat classification was variable between studies with a report improvement frequency by at least one class ranging from 0 to 54.5%. In conclusion, through careful radiographic and clinical evaluation, cervical spine involvement in patients with RA can be detected. Surgery is a valuable option for these patients and can lead to improvement in their symptoms.

Anterior occipital condyle screw placement through the endonasal corridor: proof of concept study with cadaveric analysis

PURPOSE

Odontoidectomy for ventral compressive pathology may result in O-C1 and/or C1-2 instability. Same-stage endonasal C1-2 spinal fusion has been advocated to eliminate risks associated with separate-stage posterior approaches. While endonasal methods for C1 instrumentation and C1-2 trans-articular stabilization exist, no hypothetical construct for endonasal occipital instrumentation has been validated. We provide an anatomic description of anterior occipital condyle (AOC) screw endonasal placement as proof-of-concept for endonasal craniocervical stabilization.

METHODS

Eight adult, injected cadaveric heads were studied for placing 16 AOC screws endonasally. Thin-cut CT was used for registration. After turning a standard inferior U-shaped nasopharyngeal flap endonasally, 4 mm × 22 mm AOC screws were placed with a 0° driver using neuronavigation. Post-placement CT scans were obtained to determine: site-of-entry, measured from the endonasal projection of the medial O-C1 joint; screw angulation in sagittal and axial planes, proximity to critical structures.

RESULTS

Average site-of-entry was 6.88 mm lateral and 9.74 mm rostral to the medial O-C1 joint. Average angulation in the sagittal plane was 0.16° inferior to the palatal line. Average angulation in the axial plane was 23.97° lateral to midline. Average minimum screw distances from the jugular bulb and hypoglossal canal were 4.80 mm and 1.55 mm.

CONCLUSION

Endonasal placement of AOC screws is feasible using a 0° driver. Our measurements provide useful parameters to guide optimal placement. Given proximity of hypoglossal canal and jugular bulb, neuronavigation is recommended. Biomechanical studies will ultimately be necessary to evaluate the strength of AOC screws with plate-screw constructs utilizing endonasal C1 lateral mass or C1-2 trans-articular screws as inferior fixation points.

The Impact of C1 Anterior Arch Preservation on Spine Stability After Odontoidectomy: Systematic Review and Meta-Analysis

BACKGROUND

Odontoidectomy for symptomatic irreducible ventral brainstem compression at the craniovertebral junction may result in spine instability requiring subsequent instrumentation. There is no consensus on the importance of C1 anterior arch preservation in prevention of iatrogenic instability. We conducted a systematic review of the impact of C1 anterior arch preservation on postodontoidectomy spine stability.

METHODS

PubMed, Embase, Scopus, Web of Science, and Cochrane were searched following the PRISMA guidelines to include studies of patients undergoing odontoidectomy. Random-effect model meta-analyses were performed to compare spine stability between C1 anterior arch preservation versus removal and posttreatment outcomes between transoral approaches (TOAs) versus endoscopic endonasal approaches (EEAs).

RESULTS

We included 27 studies comprising 462 patients. The most common lesions were basilar invagination (73.3%) and degenerative arthritis (12.6%). Symptoms included myelopathy (72%) and neck pain (43.9%). Odontoidectomy was performed through TOA (56.1%) and EEA corridors (34.4%). The C1 anterior arch was preserved in 16.7% of cases. Postodontoidectomy stabilization was performed in 83.3% patients. Median follow-up was 27 months (range, 0.1-145). Rates of spine instability were significantly lower (P = 0.004) when the C1 anterior arch was preserved. Postoperative clinical improvement and pooled complications were reported in 78.8% and 12.6% of patients, respectively, with no significant differences between TOA and EEA (P = 0.892; P = 0.346). Patients undergoing EEA had significantly higher rates of intraoperative cerebrospinal fluid leaks (P = 0.002).

CONCLUSIONS

Odontoidectomy is safe and effective for treating craniovertebral junction lesions. Preservation of the C1 anterior arch seems to improve maintenance of spine stability. TOA and EEA show comparable outcomes and complication rates.

C1 Lateral Mass Screw Placement Through Endonasal Corridor for Purpose of O-C1 Fusion: Morphometric Analysis in Cadaveric Specimens

BACKGROUND

Odontoidectomy may pose some risks for O-C1 and/or C1-C2 instability, with previous authors reporting techniques for endonasal C1-C2 fusion. However, no technique for endonasal O-C1 fusion currently exists. We sought to describe the feasibility of endonasal anterior C1 (AC1) screw placement for endonasal O-C1 fusion.

METHODS

Seven adult cadaveric heads were studied for endonasal placement of 14 C1 screws. Using thin-cut computed tomography (CT)-based "snapshot" neuronavigation assistance, 4 mm x 22 mm screws were placed in the C1 lateral mass using a 0° driver. Post-placement CT scans were obtained to determine site-of-entry measured from C1 anterior tubercle, screw angulation in axial and sagittal planes, and screw proximity to the central canal and foramen transversarium.

RESULTS

Average site-of-entry was 16.57 mm lateral, 2.23 mm rostral, and 5.53 mm deep to the anterior-most portion of the C1 ring. Average axial angulation was 19.49° lateral to midline, measured at the C1 level. Average sagittal angulation was 13.22° inferior to the palatal line, measured from the hard palate to the opisthion. Bicortical purchase was achieved in 11 screws (78.6%). Partial breach of the foramen transversarium was observed in 2 screws (14.3%), violation of the O-C1 joint space in 1 (7.1%), and violation of the central canal in 0 (0%). Average minimum screw distances from the unviolated foramen transversaria and central canal were 1.97 mm and 4.04 mm.

CONCLUSIONS

Navigation-assisted endonasal placement of AC1 screws is feasible. Additional studies should investigate the biomechanical stability of anterior C1 screw-plating systems, with anterior condylar screws as superior fixation point, compared to traditional posterior O-C1 fusion.

Roadmap to Ventral Craniocervical Junction Through the Endonasal Corridor: Anatomic Evaluation of Inverted U-Shaped Nasopharyngeal Flap Exposure in a Cadaveric Study

BACKGROUND

There is a paucity of data in the literature describing quantitative exposure of the ventral craniocervical junction through the endonasal corridor in a safe manner mindful of locoregional anatomy.

OBJECTIVE

To quantify ventromedial exposure of O-C1 and C1-2 articular structures after turning an inverted U-shaped nasopharyngeal flap (IUNF) and to obtain measurements assessing the distance of flap margins to adjacent neurovascular structures.

METHODS

In 8 cadaveric specimens, an IUNF was fashioned using a superior incision below the level of the pharyngeal tubercule of the clivus and lateral incisions in the approximate region of Rosenmuller fossae bilaterally. Measurements with calipers and/or neuronavigation software included flap dimensions, exposure of O-C1 and C1-2 articular structures, inferior reach of IUNF, and proximity of the internal carotid artery (ICA) and hypoglossal nerve to IUNF margins.

RESULTS

The IUNF facilitated exposure of an average of 9 mm of the medial surfaces of the right/left O-C1 joints without transgression of the carotid arteries or hypoglossal nerves. The C1-2 articulation could not be routinely accessed. The margins of the IUNF were not in close (<5 mm) proximity to the ICA in any of the 8 specimens. In 6 of 8 specimens, the dimensions of the IUNF were in close (<5 mm) horizontal or vertical proximity to the hypoglossal foramina.

CONCLUSION

The IUNF provided safe and reliable access to the medial O-C1 articulation. Given the close proximity of the exocranial hypoglossal foramen, neuronavigation assistance and neuromonitoring with attention to the superolateral IUNF margin are recommended.

Surgical outcomes of posterior occipito-cervical decompression and fusion for basilar invagination: A prospective study

STUDY DESIGN

A Prospective Study.

OBJECTIVE

To assess results of posterior occipito-cervical decompression and fusion operated with intra-operative traction/manipulation and instrumented reduction in cases of Basilar Invagination(BI).

METHODS

Total 22 patients of 8-65 years with diagnosed BI were operated for posterior occipito-cervical fusion by intra-operative traction/manipulation and instrumented reduction. Fusion was done using autologous bone graft taken from iliac crest. Immediate post-operative, first month and then every 3 months' follow-up examination were done for minimum period of 2 years.

RESULTS

22 patients (10 males,12 females) with mean age of 23.9 years having BI were included. 11 patients had C1 occipitalization, 4 had platybasia and 9 had atlanto-axial dislocation (AAD). 1 patient with os odontoideum with kyphotic deformity expired on 4th postoperative day due to respiratory insufficiency (mortality rate 4.54%). Neurological improvement by at least by one grade according to RANAWAT's and/or NURICK'S scale was observed in 17/21 patients (80.95%). 3 patients remained static and 1 had neuro-worsening. Mean mJOA score of 13.14 improved to 16.24. All had reduction of dens below foramen magnum according to McRae, chamberlain line and Ranawat index. Bone graft fused in all patients as confirmed with CT scan and dynamic X-rays. 1 wound dehiscence and 1 asymptomatic implant loosening were seen on follow-up.

CONCLUSION

Surgical treatment of BI with intra-operative traction/manipulation, instrumented reduction and posterior occipito-cervical fusion can achieve good correction of radiology, functional performance and clinical neurology as well as excellent fusion rates without adverse effects of trans-oral surgery.

[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.

Full-Endoscopic Transcervical Ventral Decompression for Pathologies of Craniovertebral Junction: Case Series

Odontoidectomy is very effective for the decompression of the ventral craniovertebral junction (CVJ). Various approaches are available for the direct ventral decompression of the CVJ. Because there are many disadvantages of open transoral approach, endoscopic odontoidectomy was developed. There are 3 approaches in endoscopic odontoidectomy. We report transcervical retropharyngeal endoscopic approach for the ventral CVJ in this paper. Three patients with different pathologies received operations using this approach. The decompression was enough and surgical invasion was less in all patients. Each endoscopic approach has some advantages and different working regions due to their approach trajectories, but transcervical retropharyngeal approach is very familiar for our neurospinal surgeons and has a relatively large working area. This approach might have the chance to take the place of open transoral approach for endoscopic spinal surgeons.

Anterior release without odontoidectomy for irreducible atlantoaxial dislocation: transoral or endoscopic transnasal?

PURPOSE

To compare transoral and endoscopic transnasal anterior release without odontoidectomy and posterior reduction and fixation to treat irreducible atlantoaxial dislocation (IAAD).

METHODS

From June 2006 to January 2017, 35 consecutive patients with IAAD underwent transoral (Tr-Oral group) or endoscopic transnasal (Tr-Nasal group) release and posterior fixation and fusion in our department. Clinical neurological recovery (Japanese Orthopedic Association (JOA) score) and radiological reduction parameters including atlantodontoid interval (ADI), space available for the cord (SAC) and cervicomedullary angle (CMA) were analyzed and compared. The operation duration, blood loss, length of intensive care unit (ICU)/hospital stay and complications were recorded.

RESULTS

All 35 patients (18 and 17 patients in the Tr-Oral and Tr-Nasal groups, respectively) were followed up for a mean of 36.4 months (range, 21-60 months). All patients achieved excellent anatomical reduction and clinical neurological recovery, with no significant differences between the two groups. The JOA score, ADI, SAC and CMA were not significantly different between the two groups at various postoperative points. Although the Tr-Oral group had shorter operation time and less blood loss than the Tr-Nasal group, the Tr-Nasal group tended to have a significantly shorter hospital/ICU stay, earlier extubation and earlier oral intake than the Tr-Oral group.

CONCLUSION

The transoral and endoscopic transnasal approaches can achieve equivalent release and reduction effects when treating IAAD. Compared to the transoral approach, the endoscopic transnasal route is less invasive with earlier extubation and oral intake, shorter hospital/ICU stays and lower medical costs, which is conducive to enhanced recovery after surgery.

Transcervical approach with endoscopic assistance for surgical treatment of patient with irreducible atlantoaxial dislocation: a case report

We demonstrate the case of a surgery in a patient with irreducible atlantoaxial dislocation (IrAAD) after C2 fracture. The challenges of this case were the flexed head in a forced position, impossibility of neck extension, and revision operation after posterior occipito-cervical fixation. The patient underwent the following surgeries: 1. A ventral release of C1-C2 using transcervical endoscopy; 2. Removal of occipito-cervical system and fibrous block resection in the posterior surfaces of the C1-C2; 3. Reducing of AAD and odontoid screw fixation; 4. Posterior C1-C2-C3 screw fixation. Ankylosing of C1-C2 and C2-C3-C4 fusion was verified by computed tomography scan. There was an improvement in patient status as observed by the increase of the SF-36 scale scores. The use of endoscopic transcervical approach is a good alternative to the transoral approach. Comparative studies of these methods should be performed regarding the choice of an optimal method of decompression in cases of IrAAD.

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.

Giant intracranial aneurysms of the posterior circulation and their relation to the brainstem: analysis of risk factors for neurological deficits

OBJECTIVE

Giant posterior circulation aneurysms (GPCirAs) usually cause substantial mass effect on the brainstem, which may lead to neurological deficits. So far, there has been no systematic investigation of factors associated with such deficits in GPCirA. The authors aim to examine the risk factors for cranial nerve deficit (CND), motor deficit, and disability in patients with GPCirA.

METHODS

Using MR images obtained in 30 patients with unruptured GPCirA, the authors examined GPCirA volume, presence of hydrocephalus or partial thrombosis (PT) of the aneurysm, and the degree of brainstem displacement measured by the distance between the McRae line and the tip of the GPCirA (∆MT). They evaluated associations between these factors and neurological deficits.

RESULTS

Thirty GPCirAs in 30 patients were included. The prevalence of CNDs was 50%. Patients with CNDs significantly differed from those without CNDs in terms of age (mean 51.0 years [SD 15.0 years] vs 69.0 years [SD 21.0 years], p = 0.01) and in ∆MT (median 50.7 mm [IQR 39.2-53.9 mm] vs 39.0 mm [IQR 32.3-45.9 mm], p = 0.02). The prevalence of motor deficits was 33.3%. Patients with motor deficits showed a larger ∆MT (median 50.5 mm [IQR 40.8-54.6 mm]) compared with those without (∆MT: median 39.1 mm [IQR 32.8-50.5 mm], p = 0.04). GPCirA volume was larger in patients with poor modified Rankin Scale (mRS) scores (median 14.9 cm3 [IQR 8.6-18.7 cm3]) than in those with mRS scores of 0-2 (median 6.8 cm3 [IQR 4.4-11.7 cm3], p = 0.03). After adjusting for patient age and the occurrence of hydrocephalus or PT, the authors found that higher degrees of disability were significantly associated with aneurysm volume (OR 1.13, 95% CI 1.0-1.3; p = 0.04), but not with ∆MT. The occurrence of CND or motor deficit was not associated with any of the examined variables. There was no correlation between GPCirA volume and ∆MT (rs = 0.01, p = 0.96). The prevalence of neurological deficits did not differ between GPCirA at the basilar apex, the basilar trunk, the vertebrobasilar junction, or the vertebral artery.

CONCLUSIONS

In this study, the neurological condition of the patients was associated only with GPCirA volume and not with the degree of brainstem displacement, the occurrence of PT or hydrocephalus, or the exact location of the GPCirA. These findings highlight the clinical relevance of GPCirA volume and suggest that factors such as brainstem displacement or PT should play less of a role when finding arguments for or against treatment of GPCirA.Clinical trial registration no.: NCT02066493 (clinicaltrials.gov).

A Dual Approach for the Management of Complex Craniovertebral Junction Abnormalities: Endoscopic Endonasal Odontoidectomy and Posterior Decompression with Fusion

BACKGROUND

Ventral brainstem compression secondary to complex craniovertebral junction abnormality is an infrequent cause of neurologic deterioration in pediatric patients. However, in cases of symptomatic, irreducible ventral compression, 360° decompression of the brainstem supported by posterior stabilization may provide the best opportunity for improvement in symptoms. More recently, the endoscopic endonasal corridor has been proposed as an alternative method of odontoidectomy associated with less morbidity. We report the largest single case series of pediatric patients using this dual-intervention surgical technique. The purpose of this study was to evaluate the surgical outcomes of pediatric patients who underwent posterior occipitocervical decompression and instrumentation followed by endoscopic endonasal odontoidectomy performed to relieve neurologic impingement involving the ventral brainstem and craniocervical junction.

METHODS

Between January 2011 and February 2017, 7 patients underwent posterior instrumented fusion followed by endonasal endoscopic odontoidectomy at our unit. Standardized clinical and radiological parameters were assessed before and after surgery. A univariate analysis was performed to assess clinical and radiologic improvement after surgery.

RESULTS

A total of 14 operations were performed on 7 pediatric patients. One patient had Ehlers-Danlos syndrome, 1 patient had a Chiari 1 malformation, and the remaining 5 patients had Chiari 1.5 malformations. Average extubation day was postoperative day 0.9. Average day of initiation of postoperative feeds was postoperative day 1.0.

CONCLUSIONS

The combined endoscopic endonasal odontoidectomy and posterior decompression and fusion for complex craniovertebral compression is a safe and effective procedure that appears to be well tolerated in the pediatric population.

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.

The full-endoscopic uniportal technique for decompression of the anterior craniocervical junction using the retropharyngeal approach: an anatomical feasibility study in human cadavers and review of the literature

Objective

Acute or progressive myelopathy may necessitate direct anterior decompression of the craniocervical junction and odontoidectomy. Different techniques with individual advantages and disadvantages can be used. In addition to the gold standard-the transoral approach-there is also increasing experience with the endoscopic transnasal technique. Other alternative methods are also being developed to reduce technical and perioperative problems. The aim of this anatomical study was to investigate the feasibility of the full-endoscopic uniportal technique with a retropharyngeal approach for decompression of the craniocervical junction, taking into consideration the specific advantages and disadvantages compared with conventional methods and the currently available data in the literature.

Methods

Five fresh adult cadavers were operated on. The endoscope used has a shaft cross-section of 6.9 × 5.9 mm and a 25° viewing angle. It contains an eccentric intraendoscopic working channel with a diameter of 4.1 mm. An anterior retropharyngeal approach was used. The anatomical structures of the anterior craniocervical junction were dissected and the bulbomedullary junction was decompressed.

Results

The planned steps of the operation were performed in all cadavers. The retropharyngeal approach allowed the target region to be accessed easily. The anatomical structures of the anterior craniocervical junction could be identified and dissected. The bulbomedullary junction could be adequately decompressed. No resections of the anterior arch of the atlas were necessary in the odontoidectomy.

Conclusions

Using the full-endoscopic uniportal technique with an anterior retropharyngeal approach, the craniocervical region can be adequately reached, dissected, and decompressed. This is a minimally invasive technique with the known advantages of an endoscopic procedure under continuous irrigation. The retropharyngeal approach allows direct, sterile access. The instruments are available for clinical use and have been established for years in other operations of the entire spine.

Endoscopic Endonasal Resection of the Odontoid Process in a Patient with Chronic Injury of the C1 Transverse Ligament

Atlas dislocation after transverse ligament injury is one of the most rare types of trauma to the upper cervical level. If magnetic resonance imaging of the craniovertebral junction reveals the Kassam line passing through the cervix of the odontoid process, a transnasal approach can be used for surgical treatment. Here, we present a case in which an endoscopic endonasal approach was used to treat chronic traumatic transligamentous atlas dislocation. A 26-year-old male underwent two-stage surgical treatment; during the first stage, posterior decompression and fixation were performed under halo immobilization. In the second stage, a transnasal endoscopic approach to the odontoid process was used. A transnasal approach permitted complete decompression of the medulla oblongata and facilitated early extubation of the patient without any postoperative complications such as respiratory or pharyngopalatine deficiency. The patient was discharged in good condition 9 days after the surgery.

Full-endoscopic uniportal retropharyngeal odontoidectomy for anterior craniocervical infection

BACKGROUND

Infections of the anterior craniocervical junction may require surgery. There are various techniques with individual advantages and disadvantages. This study evaluates the full-endoscopic uniportal technique via the anterior retropharyngeal approach for odontoidectomy, decompression, and debridement.

MATERIAL AND METHODS

Three patients with an infection of the anterior craniocervical junction with retrodental involvement were operated on between 2014 and 2016 using the full-endoscopic uniportal technique. Posterior stabilization was also performed with the same procedure for all patients.

RESULTS

The operation was technically satisfactory in all cases. No problems due to swelling of the pharyngeal soft tissue occurred. No other complications were observed. All patients had a satisfactory outcome with stable regression of the myelopathy symptoms and/or complete healing of the infection. The follow-up images showed sufficient decompression of bone and soft tissues in all cases.

CONCLUSIONS

The full-endoscopic uniportal technique with an anterior retropharyngeal approach can be an adequate and minimally invasive surgical technique for odontoidectomy, decompression, and debridement in infections of the craniocervical junction and can reduce access-related problems. The transoral, transnasal, and retropharyngeal approaches have different surgical fields due to the access trajectories, which must be taken into consideration depending on the anatomy and pathology when selecting a suitable technique.

Full-endoscopic Uniportal Odontoidectomy and Decompression of the Anterior Cervicomedullary Junction Using the Retropharyngeal Approach

STUDY DESIGN

A study of a series of consecutive full-endoscopic uniportal decompressions of the anterior craniocervical junction with retropharyngeal approach.

OBJECTIVE

The aim of this study was to evaluate the direct anterior decompression of the craniocervical junction in patients with bulbomedullary compression using a full-endoscopic uniportal technique via an anterolateral retropharyngeal approach.

SUMMARY OF BACKGROUND DATA

Acute or progressive myelopathy may necessitate direct anterior decompression of the craniocervical junction and odontoidectomy. Different techniques with individual advantages and disadvantages can be used. In addition to the gold standard - the transoral approach - there is increasing experience with the endoscopic transnasal technique. Other alternative procedures are also being developed.

METHODS

Between 2013 and 2016, eight patients with basilar impression, retrodental pannus, or retrodental infection were operated in the full-endoscopic uniportal technique with a retropharyngeal approach. Anterior decompression of the bulbomedullary junction with odontoidectomy was performed. All patients additionally underwent posterior stabilization. Imaging and clinical data were collected in follow-up examinations for 1 year.

RESULTS

The bulbomedullary junction was adequately decompressed. No problems due to swelling of pharyngeal soft tissue occurred. One patient required revision due to secondary bleeding. No other complications were observed. All patients had a good clinical outcome with stable regression of the myelopathy symptoms and/or healing of the infection. The imaging follow-up showed sufficient decompression of bone and soft tissue in all cases. No evidence was found of increasing instability or failure of posterior fusion.

CONCLUSION

In the operated patients, the full-endoscopic uniportal surgical technique with anterior retropharyngeal approach was found to be a sufficient and minimally invasive method with the known advantages of an endoscopic procedure under continuous irrigation. It should not be viewed only as competition for other surgical techniques - due to its individual technical parameters, it can also be considered to be an alternative or complementary procedure.

LEVEL OF EVIDENCE

4.

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.

Direct and Oblique Approaches to the Craniovertebral Junction: Nuances of Microsurgical and Endoscope-Assisted Techniques Along with a Review of the Literature

PURPOSE

The aim of this review is to provide an update of the technical nuances of microsurgical and endoscopic-assisted approaches to the craniovertebral junction (transnasal, transoral, and transcervical), and to report on the available clinical results in order to identify the best strategy.

METHODS

A nonsystematic update of the reviews and reporting on the anatomical and clinical results of endoscopic-assisted and microsurgical approaches to the craniovertebral junction (CVJ) was performed.

RESULTS

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

CONCLUSIONS

The transoral (microsurgical or video-assisted) approach with sparing of the soft palate still remains the gold standard compared with the "pure" transnasal and transcervical approaches, due to 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. Of particular interest is the evidence that advances in reduction techniques can avoid the ventral approach.

[The rheumatic cervical spine]

BACKGROUND

The cervical spine is one of the main sites of manifestation in rheumatoid arthritis outside of the extremities. It can have a decisive influence on disease course via the occurrence of mechanical instabilities as well as neurologic symptoms. Both adequate diagnosis and the corresponding surgical treatment represent a challenge for the involved physicians.

MATERIALS AND METHODS

This review presents relevant diagnostic strategies and possibilities for surgical intervention which aim to avoid potentially fatal neurologic symptoms. Basic literature and expert opinions are also discussed.

RESULTS AND CONCLUSION

Through target-oriented surgical management, as well as tight clinical and radiologic monitoring during conservative and surgical therapy, potentially fatal disease courses can be avoided.

Three-Dimensional, computer simulated navigation in endoscopic neurosurgery

BACKGROUND

In order to address the pre- and perioperative need for visualization and prediction of patient-specific anatomy for surgical planning, endoscopic neurosurgeons have increasingly relied on computerized navigation devices to guide their surgical approaches.

OBJECTIVE

This manuscript aims to review: 1) the use of neuronavigation in endoscopic neurosurgery for pre-operative planning, 2) the intraoperative advantages of neuronavigation in endoscopic neurosurgery, and 3) the effects of navigation guidance on operative time, registration accuracy, brain shift, and avoidance of complications. Limitations of the current neuroendoscopic navigation literature will be discussed.

METHODS

We conducted a search using PubMed-MEDLINE; the keywords "stereotactic navigation AND endoscopic surgery" and "simulation AND endoscopic neurosurgery". 36 studies were identified that addressed the use of neuronavigation in endoscopic neurosurgery. These studies were then further analyzed for topics relevant to computerized neuroendoscopy and reviewed for the purposes of this article.

CONCLUSION

Three-dimensional, frameless neuronavigation systems are useful in endoscopic neurosurgery to assist in the pre-operative planning of potential trajectories and to help localize the pathology of interest. Neuronavigation appears to be accurate to < 1-2 mm without issues related to brain shift. Further work is necessary in the investigation of the effect of neuronavigation on operative time, cost, and patient-centered outcomes.

Use of Frameless Stereotactic Neuronavigation and O-arm for Transoral Transpalatal Odontoidectomy to Treat a Very High Basilar Invagination

Frameless stereotactic neuronavigation system has been in wide use since many years for precise localization of cranial tumors and navigation for spinal instrumentation. We present its usage in the localization of odontoid process in a very high basilar invagination for a transoral transpalatal resection of the same. We discuss the technical aspects of assembly of neuronavigation system, O-arm and Mayfield head frame on Allen spine system to achieve precise and accurate localization of high riding odontoid process through an extremely narrow operative corridor.

Endoscopic Transnasal Odontoidectomy

Transoral microscopic odontoidectomy followed by posterior fixation has been accepted as a standard procedure to treat nonreducible basilar invagination during the half past century. In recent years, the development of endoscopic techniques has raised challenges regarding the traditional treatment algorithm. The endoscopic transnasal odontoidectomy is a feasible and effective method in the treatment of irreducible ventral cervicomedullary junction compression, which has several advantages over the transoral approach. The endoscopic odontoidectomy includes transnasal, transoral, and transcervical approaches. The 3 different approaches for endoscopic odontoidectomy present complementary advantages and limitations. The necessity of posterior fixation after odontoidectomy should be considered in every single case on the basis of the peculiar anatomic and clinical conditions.

Selection of surgical procedures for basilar invagination with atlantoaxial dislocation

BACKGROUND CONTEXT

Basilar invagination (BI) is a malformation of craniovertebral junction. However, surgical procedures on BI with atlantoaxial dislocation (AAD) remain controversial.

PURPOSE

This research aimed to investigate the selection of surgical procedures and its significance in the surgical treatment of patients with BI and AAD.

STUDY DESIGN

This was a retrospective study.

PATIENT SAMPLE

This study enrolled 33 patients who were diagnosed with BI and AAD and were followed up for at least 6 months.

OUTCOME MEASURE

All of the patients were assessed for neurologic recovery observation in terms of Japanese Orthopaedic Association scores and Odom criteria. X-ray, magnetic resonance imaging, or computed tomography scanning was used to determine reduction, compression, bone graft, and internal fixation before and after operation.

METHODS

Thirty-three patients who suffered from BI with AAD were treated in our department from July 2000 to October 2014. Preoperatively, the patients were divided into two types on the basis of whether dislocation was reduced after anesthesia and traction were performed: reducible dislocation (Type A) and irreducible dislocation (Type B). Reducible dislocation was further divided into two subtypes: full reducible dislocation (Type A1) and partial reducible dislocation (Type A2). Type A1 patients were treated with direct posterior fixation and fusion after traction and reduction. Type A2 patients received posterior atlantoaxial release, fixation, and fusion under traction. Type B patients underwent transoral atlantoaxial release, posterior fixation, and fusion.

RESULTS

There were 5 Type A1 patients, 10 Type A2 patients, and 18 Type B patients treated in accordance with the proposed scheme. Postoperatively, sufficient reduction and decompression were achieved for all cases. Two Type B patients died. Other patients were followed up from 6 months to 42 months (average=16.6 months); follow-up results showed sufficient decompression, effective fixation and fusion, and no reduction loss. The Japanese Orthopaedic Association Score increased from preoperative 4-12 (average, 7.8) to postoperative 10-17 (average, 14.3), and neurologic recovery was satisfactory.

CONCLUSIONS

Under traction, simple posterior fixation and fusion were effective for Type A patients suffering from BI with AAD; anterior atlantoaxial release and posterior fixation and fusion were effective for Type B patients with BI and AAD.

Endoscopic Approaches to the Craniovertebral Junction

The endoscopic endonasal approach provides a direct surgical trajectory to anteriorly located lesions at the craniovertebral junction. The inferior limit of surgical exposure is predicted by the nasopalatine line, and the lateral limit is demarcated by the lower cranial nerves. Endoscopic endonasal odontoidectomy allows preservation of the soft palate, and patients can restart an oral diet on the first postoperative day. Treating the condition at the craniovertebral junction using this approach requires careful preoperative planning and endoscopic endonasal surgical experience with a 2-surgeon 4-handed approach combining expertise in otolaryngology and neurosurgery.

Orthopaedic Considerations for the Adult With Osteogenesis Imperfecta

Osteogenesis imperfecta is a heritable group of collagen-related disorders that affects up to 50,000 people in the United States. Although the disease is most symptomatic in childhood, adults with osteogenesis imperfecta also are affected by the sequelae of the disease. Orthopaedic manifestations include posttraumatic and accelerated degenerative joint disease, kyphoscoliosis, and spondylolisthesis. Other manifestations of abnormal collagen include brittle dentition, hearing loss, cardiac valve abnormalities, and basilar invagination. In general, nonsurgical treatment is preferred for management of acute fractures. High rates of malunion, nonunion, and subsequent deformity have been reported with both closed and open treatment. When surgery is necessary, surgeons should opt for load-sharing intramedullary devices that span the entire length of the bone; locking plates and excessively rigid fixation generally should be avoided. Arthroplasty may be considered for active patients, but the procedure frequently is associated with complications in this patient population. Underlying deformities, such as malunion, bowing, rotational malalignment, coxa vara, and acetabular protrusio, pose specific surgical challenges and underscore the importance of preoperative planning.

The rise and fall of the craniocervical junction relative to the hard palate: a lifetime story

OBJECT

Endoscopic approaches to the anterior craniocervical junction are increasing in frequency. Choice of oral versus endoscopic endonasal approach to the odontoid often depends on the relationship of the C1–2 complex to the hard palate. However, it is not known how this relevant anatomy changes with age. We hypothesize that there is a dynamic relationship of C-2 and the hard palate, which changes with age, and potentially affects the choice of surgical approach. The aim of this study was to characterize the relationship of C-2 relative to the hard palate with respect to age and sex.

METHODS

Emergency department billing and trauma records from 2008 to 2014 were reviewed for patients of all ages who underwent cervical or maxillofacial CT as part of a trauma evaluation for closed head injury. Patients who had a CT scan that allowed adequate visualization of the hard palate, opisthion, and upper cervical spine (C-1 and C-2) were included. Patients who had cervical or displaced facial/skull base fractures, a history of rheumatoid arthritis, or craniofacial anomalies were excluded. The distance from McGregor's palatooccipital line to the midpoint of the inferior endplate of C-2 (McL–C2) was measured on midsagittal CT scans. Patients were grouped by decile of age and by sex. A 1-way ANOVA was performed with each respective grouping.

RESULTS

Ultimately, 483 patients (29% female) were included. The mean age was 46 ± 24 years. The majority of patients studied were in the 2nd through 8th decades of life (85%). Significant variation was found between McL–C2 and decile of age (p < 0.001) and sex (p < 0.001). The mean McL–C2 was 27 mm in the 1st decade of life compared with the population mean of 37 mm. The mean McL–C2 was also noted to be smaller in females (mean difference 4.8 mm, p < 0.0001). Both decile of age (p = 0.0009) and sex (p < 0.0001) were independently correlated with McL–C2 on multivariate analysis.

CONCLUSIONS

The relationship of C-2 and the hard palate significantly varies with respect to age and sex, descending relative to the hard palate a full centimeter on average in adulthood. These findings may have relevance in determining optimal surgical approaches for addressing pathology involving the anterior craniocervical junction.

The endoscopic transoral approach to the craniovertebral junction: an anatomical study with a clinical example

OBJECTIVE

The microscopic transoral, endoscopic transnasal, and endoscopic transoral approaches are used alone and in combination for a variety of craniovertebral junction (CVJ) pathologies. The endoscopic transoral approach provides a more direct exposure that is not restricted by the nasal cavity, pterygoid plates, and palate while sparing the potential morbidities associated with extensive soft-tissue dissection, palatal splitting, or mandibulotomy. Concerns regarding the extent of visualization afforded by the endoscopic transoral approach may be limiting its widespread adoption.

METHODS

A dissection of 10 cadaver heads was undertaken. CT-based imaging guidance was used to measure the working corridor of the endoscopic transoral approach. Measurements were made relative to the palatal line. The built-in linear measurement tool was used to measure the superior and inferior extents of view. The superolateral extent was measured relative to the midline, as defined by the nasal process of the maxilla. The height of the clivus, odontoid tip, and superior aspect of the C-1 arch were also measured relative to the palatal line. A correlated clinical case is presented with video.

RESULTS

The CVJ was accessible in all cases. The superior extent of the approach was a mean 19.08 mm above the palatal line (range 11.1–27.7 mm). The superolateral extent relative to the midline was 15.45 mm on the right side (range 9.6–23.7 mm) and 16.70 mm on the left side (range 8.1–26.7 mm). The inferior extent was a mean 34.58 mm below the palatal line (range 22.2–41.6 mm). The mean distances were as follows: palatal line relative to the odontoid tip, 0.97 mm (range −4.9 to 3.7 mm); palatal line relative to the height of the clivus, 4.88 mm (range −1.5 to 7.3 mm); and palatal line relative to the C-1 arch, −2.75 mm (range −5.8 to 0 mm).

CONCLUSIONS

The endoscopic transoral approach can reliably access the CVJ. This approach avoids the dissections and morbidities associated with a palate-splitting technique (velopharyngeal insufficiency) and the expanded endonasal approach (mucus crusting, sinusitis, and potential lacerum or cavernous-paraclival internal carotid artery injury). For appropriately selected lesions near the palatal line, the endoscopic transoral approach appears to be the preferred approach.

Complications of transoral and transnasal odontoidectomy: a comprehensive review

BACKGROUND

Odontoidectomy has been considered an effective way to treat anterior cervicomedullary compression in patients presenting with craniocervical joint anomalies. The transoral and transnasal routes have been described for anterior decompression surgery. However, to date, a comprehensive review of the complications from this procedure is lacking in the extant medical literature. Therefore, herein, we review this specific literature as a resource for surgeons.

METHODS

A comprehensive review of the literature via online search engines was performed.

CONCLUSION

The most reported complications for odontoidectomy are CSF leakage, postoperative craniocervical instability, velopharyngeal insufficiency, wound dehiscence, pulmonary issues, meningitis, and death. To our knowledge, this is the first comprehensive review of complications of odontoidectomy. Increased awareness of the more common complications associated with this procedure may help in the care of patients in the future.

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

BACKGROUND

The transoral ventral corridor is the most common approach used to reach the craniovertebral junction (CVJ). Over the last decade, many case reports have demonstrated the transnasal corridor to the odontoid peg represents a practicable route to remove the tip of the odontoid process. The biomechanical consequences of the traditional odontoidectomy led to the necessity of a cervical spine stabilization. Preserving the inferior portion of the C1 anterior arch should prevent instability.

CASE DESCRIPTION

This is the first report in which the technique to remove the tip of the odontoid while preserving the C1 anterior arch is described by means of a three-dimensional (3D) endoscope. A 53-year-old man underwent a transnasal 3D endoscopic approach because of a complex CVJ malformation. The upper-medial portion of the C1 anterior arch was removed preserving its continuity, and the odontoidectomy was performed. After surgery, a dynamic X-ray scan showed no difference in CVJ motility in comparison with the preoperative one.

CONCLUSIONS

The stereoscopic perception augmented the precision of the surgical gesture in the deep field. The importance of a 3D view relates to the depth of field, which a two-dimensional endoscopy cannot provide. This affects the preservation of the C1 anterior arch because of the presence of critical structures that are exposed to potential damage if not displayed.

Endoscopic endonasal approach for craniovertebral junction pathology: a review of the literature

OBJECT

The transoral approach is the gold standard for ventral decompression of the brainstem caused by craniovertebral junction (CVJ) pathology. This approach is often associated with significant morbidity, related to swallowing and respiratory complications. The endoscopic endonasal approach was introduced to reduce the rate of these complications. However, the exact role of this approach in the treatment of CVJ pathology is not well defined.

METHODS

A comprehensive literature search was performed to identify series of patients with pathology of the CVJ treated via the endoscopie endonasal approach. Data on patient characteristics, indications for treatment, complications, and outcome were obtained and analyzed.

RESULTS

Twelve studies involving 72 patients were included. The most common indications for treatment were rheumatoid pannus (38.9%) and basilar invagination (29.2%). Cerebrospinal fluid leak was found in 18% of cases intraoperatively and 4.2% of cases postoperatively. One case of meningitis complicated by sepsis and death represents the procedure-related mortality of 1.4%. Of the patients without preoperative swallowing impairment, 95% returned to oral feeding on the 3rd postoperative day. Ninety-three percent of patients experienced improvement in neurological symptoms after the procedure.

CONCLUSIONS

The endonasal endoscopie approach is effective for the treatment of neural compression caused by CVJ pathology. It offers advantages such as lower rates of postoperative dysphagia and respiratory complications when compared with the more traditional transoral approach. However, these 2 approaches should be seen as complementary rather than alternatives. Patient-related factors as well as the surgeon's expertise must be considered when making treatment decisions.

Endoscopic endonasal transclival transodontoid approach for ventral decompression of the craniovertebral junction: operative technique and nuances

The transoral approach is considered the gold-standard surgical route for performing anterior odontoidectomy and ventral decompression of the craniovertebral junction for pathological conditions that result in symptomatic cervicomedullary compression, including basilar invagination, rheumatoid pannus, platybasia with retroflexed odontoid processes, and neoplasms. Extended modifications to increase the operative corridor and exposure include the transmaxillary, extended "open-door" maxillotomy, transpalatal, and transmandibular approaches. With the advent of extended endoscopic endonasal skull base techniques, there has been increased interest in the last decade in the endoscopic endonasal transclival transodontoid approach to the craniovertebral junction. The endonasal route represents an attractive minimally invasive surgical alternative, especially in cases of irreducible basilar invagination in which the pathology is situated well above the palatine line. Angled endoscopes and instrumentation can also be used for lower-lying pathology. By avoiding the oral cavity and subsequently using a transoral retractor, the endonasal route has the advantages of avoiding complications related to tongue swelling, tracheal swelling, prolonged intubation, velopharyngeal insufficiency, dysphagia, and dysphonia. Postoperative recovery is quicker, and hospital stays are shorter. In this report, the authors describe and illustrate their method of purely endoscopic endonasal transclival odonotoidectomy for anterior decompression of the craniovertebral junction and describe various operative pearls and nuances of the technique for avoiding complications.

Videoassisted anterior surgical approaches to the craniocervical junction: rationale and clinical results

PURPOSE

In this narrative review, we aim to give an update on the anatomic fundamentals of endoscopic assisted surgery to the craniocervical junction (transnasal, transoral and transcervical), and to report on the available clinical results.

METHODS

A non-systematic review and reporting on the anatomical and clinical results of endoscopic assisted approaches to the craniocervical junction (CVJ) is performed.

RESULTS

Pure endonasal and cervical endoscopic approaches still have some disadvantages, including the learning curve and the lack of 3-dimensional perception of the surgical field. Endoscopically assisted transoral surgery with 30° endoscopes represents an emerging alternative to standard microsurgical techniques for transoral approaches to the anterior CVJ. Used in conjunction with traditional microsurgery and intraoperative fluoroscopy, it provides a safe and improved method for anterior decompression with or without a reduced need for extensive soft palate splitting, hard palate resection, or extended maxillotomy.

CONCLUSIONS

Transoral (microsurgical or video-assisted) approach with sparing of the soft palate still remains the gold standard compared to the "pure" transnasal and transcervical approaches due to the wider working channel provided by the former technique. Transnasal endoscopic approach alone appears to be superior when the CVJ lesion exceeds the upper limit of the inferior third of the clivus. Combined transnasal and transoral procedures can be tailored according to the specific pathological and radiological findings.

Rheumatoid Arthritis and the Cervical Spine: A Review on the Role of Surgery

Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease affecting a significant percentage of the population. The cervical spine is often affected in this disease and can present in the form of atlantoaxial instability (AAI), cranial settling (CS), or subaxial subluxation (SAS). Patients may present with symptoms and disability secondary to these entities but may also be neurologically intact. Cervical spine involvement in RA can pose a challenge to the clinician and the appropriate role of surgical intervention is controversial. The aim of this paper is to describe the pathology, pathophysiology, clinical manifestations, and diagnostic evaluation of rheumatoid arthritis in the cervical spine in order to provide a better understanding of the indications and options for surgery. Both the medical and surgical treatment options for RA have improved, so has the prognosis of the cervical spine disease. With the advent of disease modifying antirheumatic drugs (DMARDs), fewer patients are presenting with cervical spine manifestations of RA; however, those that do, now have improved surgical techniques available to them. We hope that, by reading this paper, the clinician is able to better evaluate patients with RA in the cervical spine and determine in which patients surgery is indicated.

Basilar Invagination: Case Report and Literature Review

BACKGROUND

Basilar invagination is a rare clinical condition characterized by upward protrusion of the odontoid process into the intracranial space, leading to bulbomedullary compression. It is often encountered in adults with rheumatoid arthritis. Transoral microscopic or endonasal endoscopic decompression may be pursued, with or without posterior fixation. We present a case of basilar invagination with C1-C2 autofusion and discuss an algorithm for choice of anterior versus posterior approaches.

CASE DESCRIPTION

A 47-year-old woman with rheumatoid arthritis presented with severe occipital and cervical pain, dysphagia, hoarseness, and arm paresthesias. Findings on magnetic resonance imaging revealed moderate cranial settling with the odontoid indenting the ventral medulla but no posterior compression. Computed tomography demonstrated bony fusion at C1-C2 without lateral sag. Given autofusion of C1-C2 in proper occipitocervical alignment and the absence of posterior compression, the patient underwent endoscopic endonasal odontoidectomy without further posterior fusion, with satisfactory resolution of symptoms.

CONCLUSION

Endoscopic endonasal odontoidectomy offers a safe and effective method for anterior decompression of basilar invagination. Preoperative assessment for existing posterior fusion, absence of posterior compression, and preservation of the anterior C1 ring during operative decompression help stratify the need for lone anterior approach versus a combined anterior and posterior treatment.

Endoscopic endonasal atlantoaxial transarticular screw fixation technique: an anatomical feasibility and biomechanical study

OBJECT The primary disadvantage of the posterior cervical approach for atlantoaxial stabilization after odontoidectomy is that it is conducted as a second-stage procedure. The goal of the current study is to assess the surgical feasibility and biomechanical performance of an endoscopic endonasal surgical technique for C1-2 fixation that may eliminate the need for posterior fixation after odontoidectomy. METHODS The first step of the study was to perform endoscopic endonasal anatomical dissections of the craniovertebral junction in 10 silicone-injected fixed cadaveric heads to identify relevant anatomical landmarks. The second step was to perform a quantitative analysis using customized software in 10 reconstructed adult cervical spine CT scans to identify the optimal screw entry point and trajectory. The third step was biomechanical flexibility testing of the construct and comparison with the posterior C1-2 transarticular fixation in 14 human cadaveric specimens. RESULTS Adequate surgical exposure and identification of the key anatomical landmarks, such as C1-2 lateral masses, the C-1 anterior arch, and the odontoid process, were provided by the endonasal endoscopic approach in all specimens. Radiological analysis of anatomical detail suggested that the optimal screw entry point was on the anterior aspect of the C-1 lateral mass near the midpoint, and the screw trajectory was inferiorly and slightly laterally directed. The custommade angled instrumentation was crucial for screw placement. Biomechanical analysis suggested that anterior C1-2 fixation compared favorably to posterior fixation by limiting flexion-extension, axial rotation, and lateral bending (p > 0.3). CONCLUSIONS This is the first study that demonstrates the feasibility of an endoscopic endonasal technique for C1-2 fusion. This novel technique may have clinical utility by eliminating the need for a second-stage posterior fixation operation in certain patients undergoing odontoidectomy.

The endoscopic endonasal approach to the odontoid and its impact on early extubation and feeding

OBJECT

The gold-standard surgical approach to the odontoid is via the transoral route. This approach necessitates opening of the oropharynx and is associated with risks of infection, and swallowing and breathing complications. The endoscopic endonasal approach has the potential to reduce these complications as the oral cavity is avoided. There are fewer than 25 such cases reported to date. The authors present a consecutive, single-institution series of 9 patients who underwent the endonasal endoscopic approach to the odontoid.

METHODS

The charts of 9 patients who underwent endonasal endoscopic surgery to the odontoid between January 2005 and August 2013 were reviewed. The clinical presentation, radiographic findings, surgical management, complications, and outcome, particularly with respect to time to extubation and feeding, were analyzed. Radiographic measurements of the distance between the back of the odontoid and the front of the cervicomedullary junction (CMJ) were calculated, as well as the location of any residual bone fragments.

RESULTS

There were 7 adult and 2 pediatric patients in this series. The mean age of the adults was 54.8 years; the pediatric patients were 7 and 14 years. There were 5 females and 4 males. The mean follow-up was 42.9 months. Symptoms were resolved or improved in all but 1 patient, who had concurrent polyneuropathy. The distance between the odontoid and CMJ increased by 2.34 ± 0.43 mm (p = 0.03). A small, clinically insignificant fragment remained after surgery, always on the left side, in 57% of patients. Mean times to extubation and oral feeding were on postoperative Days 0.3 and 1, respectively. There was one posterior cervical wound infection; there were 2 cases of epistaxis requiring repacking of the nose and no instances of breathing or swallowing complications or velopharyngeal insufficiency.

CONCLUSIONS

This series of 9 cases of endonasal endoscopic odontoidectomy highlights the advantages of the approach in permitting early extubation and early feeding and minimizing complications compared with transoral surgery. Special attention must be given to bone on the left side of the odontoid if the surgeon is standing on the right side.

Endoscopic transnasal odontoidectomy without resection of nasal turbinates: clinical outcomes of 13 patients

Object The goal of the study was to report a series of consecutive patients who underwent endoscopic transnasal odontoidectomy (ETO) without resection of nasal turbinates. The techniques for this minimally invasive approach are described in detail. Methods The authors conducted a retrospective review of consecutive patients who underwent ETO for basilar invagination. All the patients had myelopathy caused by compression at the cervicomedullary junction, which required surgical decompression. Preoperative and postoperative data, including those from radiographic and clinical evaluations, were compared. Morbidity and mortality rates for the procedure are also reported in detail. Results Thirteen patients (6 men and 7 women) with a mean age of 52.7 years (range 24-72 years) were enrolled. The basilar invagination etiologies were rheumatoid arthritis (n = 5), trauma (n = 4), os odontoideum (n = 2), ankylosing spondylitis (n = 1), and postinfectious deformity (n = 1). The average follow-up duration was 51.2 months (range 0.3-105 months). One patient died 10 days after the operation as a result of meningitis caused by CSF leakage. Among the other 12 patients, the average postoperative Nurick grade (3.2) was significantly improved over that before the operation (4.1, p = 0.004). The mean (± SD) duration of postoperative intubation was 1.5 ± 2.1 days, and there was no need for perioperative tracheostomy or nasogastric tube feeding. There also was no postoperative velopharyngeal insufficiency. There were 6 (46%) intraoperative and 2 (15%) postoperative CSF leaks in the 13 patients in this series. Conclusions ETO is a viable and effective option for decompression at the ventral cervicomedullary junction. This approach is minimally invasive and causes little velopharyngeal insufficiency. The pitfall of this approach is the difficulty in repairing dural defects and subsequent CSF leakage.

Advances in the treatment of cervical rheumatoid: Less surgery and less morbidity

Rheumatoid arthritis is a chronic systemic inflammatory disease that often affects the cervical spine. While it was initially thought that cervical involvement was innocuous, natural history studies have substantiated the progressive nature of untreated disease. Over the past 50 years, there has been further elucidation in the pathophysiology of the disease, as well as significant advancements in medical and surgical therapy. The introduction of disease modifying drugs and biologic agents has reduced the amount of patients with advanced stages of the disease needing surgery. Advancement in instrumentation techniques has improved patient outcomes and fusion rates. The introduction of endoscopic approaches for ventral decompression may further lower surgical morbidity. In this review, we give a brief overview of the pertinent positives of the disease. A discussion of historical techniques and the evolution of surgical therapy into the modern era is provided. With improved medical therapies and less invasive approaches, we will likely continue to see less advanced cases of disease and less surgical morbidity. Nonetheless, a thorough understanding of the disease is crucial, as its systemic involvement and need for continued medical therapy have tremendous impact on overall complications and outcomes even in patients being seen for standard degenerative disease with comorbid rheumatoid.