Atlantoaxial Joint Distraction for the Treatment of Basilar Invagination: Clinical Outcomes and Radiographic Evaluation

doi:10.1016/j.wneu.2017.12.013

World Neurosurgery

Volume 111, March 2018, Pages e135-e141

https://doi.org/10.1016/j.wneu.2017.12.013 Get rights and content

Objective

To investigate the causes of partial remission in patients with basilar invagination (BI) and irreducible atlantoaxial dislocation (IAAD) treated with transoral atlantoaxial reduction plate (TARP) without odontoidectomy and quantify the distance of odontoid descent.

Methods

Between August 2010 and July 2012, 22 consecutive patients with BI with IAAD who underwent TARP surgery were reviewed. The preoperative and postoperative radiographic parameters were evaluated. Follow-up data and the symptom treatment interval (STI), defined as the interval between the onset of symptoms and surgical treatment, were assessed. Neurological function was evaluated as neurologic improvement, defined as ([Postoperative Japanese Orthopedic Association (JOA) score] − [Preoperative JOA score])/(17 − [Preoperative JOA score]). The patients were assigned to group A (<50%) or group B (≥50%) based on their level of neurologic improvement.

Results

All 22 patients improved clinically to varying degrees. The mean preoperative STI was 105.6 ± 67.6 months for group A and 45.3 ± 46.7 months for group B (P < 0.05). There were no significant between-group differences in follow-up (P > 0.05) or with respect to radiographic parameters (P > 0.05). Persistent brainstem compression was observed in 1 patient, whose symptoms were not adequately relieved after revision surgery (transoral odontoidectomy and posterior decompression and fusion). No fixation failure was observed.

Conclusions

Descent of the odontoid process is useful for treating basilar invagination. TARP surgery without odontoidectomy may pull the dens caudally and ventrally to achieve sufficient decompression of the spinal cord. Neurologic improvement may be associated with STI.

Introduction

Basilar invagination (BI) is a complex deformity of the craniovertebral junction with the major pathological feature of direct brainstem compression due to the dens. Improving the surgical techniques used to treat BI should enhance surgical efficacy and reduce complications. Currently, the most common surgical procedure used to manage BI is direct transoral decompression with single-stage posterior instrumentation; however, the rates of surgical injury and complications are high with dens and/or clivus resection.1, 2 Several studies have demonstrated that reducing the dens using an anterior-only or posterior-only approach may effectively decompress the spinal cord while decreasing the complication rate associated with spinal deformity surgery.3, 4, 5, 6, 7, 8 Goel et al.⁴ described a novel technique for treating BI by receding the dens using a posterior-only approach; however, sufficient descent of the dens was not achieved in most cases, and atlantoaxial dislocation (AAD) was not always reduced. In a previous study, we demonstrated that sufficient decompression can be achieved via transoral atlantoaxial reduction plate (TARP) surgery (Figure 1C and G)⁹; however, adequate relief of symptoms was not always achieved, and the distance of odontoid descent was unknown. In the present study, we investigated the causes of partial remission in patients with BI and irreducible AAD (IAAD) treated with TARP surgery, and we quantified the distance of the odontoid process descent.

Section snippets

Patients

We enrolled 22 consecutive patients who underwent the TARP operation performed by the same surgeon between August 2010 and July 2012 (Table 1). The cohort comprised 9 men and 13 women with a mean age of 32 years (range, 8–57 years), an average follow-up of 67 months (range, 55–81 months), and an average preoperative STI of 59 months (range, 6–180 months). The exclusion criteria were previous posterior instrumented fixation and craniovertebral junction tumor or infection. The patients were

Results

All 22 patients improved clinically to various degrees. One patient in group A who had urinary hesitancy improved only partially. One patient in group B who had dyspnea improved completely. The mean preoperative STI was 105.6 ± 67.6 months for group A and 45.3 ± 46.7 months for group B (P < 0.05). There was no significant between-group difference in follow-up (P > 0.05) (Table 1). Postoperative ADI was restored completely in all 22 patients, and postoperative CL was restored completely in 8

Discussion

Treatment for BI with IAAD is a controversial and challenging topic. Conventional surgery uses transoral release or odontoidectomy, followed by posterior fixation and fusion. Potential risks and complications are associated whether an anterior or posterior approach is used. Several studies have reported novel techniques demonstrating that receding the odontoid process using either an anterior-only or posterior-only approach can effectively prevent damage to the brainstem.4, 5, 7, 8, 9, 16

The

Conclusions

Descent of the odontoid process is useful for treating BI. Performing a TARP operation without odontoidectomy may pull the dens caudally and ventrally to achieve sufficient decompression of the spinal cord. Neurologic improvement may be associated with STI.

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Cited by (16)

Transcranial Insertion of Atlas Facetal Screw for Atlantoaxial Fixation
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Citation Excerpt :
In addition, the occipitocervical implant will severely restrict neck movement. Our experience has suggested that direct screw fixation in the facet of the atlas, even in patients with assimilation of the atlas, is significantly superior to insertion of screws into the occipital bone.1,10,11,15,16 The long length of the screw possible in the strong and largely cortical nature of the bone of the facet of the atlas provides the ground for solid screw purchase.
We evaluated the technical feasibility and potential advantages of transcranial insertion of an atlas screw for atlantoaxial fixation.
From January 2016 to August 2018, the transcranial technique for atlas screw insertion was used in 6 patients. Conventional lateral mass atlantoaxial fixation was not possible because of the presence of a complex craniovertebral junctional abnormality and difficulty in direct exposure of the facet of the atlas. In all cases, severe basilar invagination and assimilation of the atlas was present. Of the 6 patients, 3 were male and 3 were female. The age range was 12–41 years (average, 23 years). The surgical technique involved a small suboccipital craniotomy in line with the facet of the axis. Extradural elevation of the cerebellum exposed the region of the occipital condyle and fused atlas. The screw was directed medially and inferiorly into the facet of the atlas.
In all 6 patients, strong and successful atlantoaxial fixation was achieved. All patients showed clinical improvement after surgery. At an average follow-up period of 21 months, successful arthrodesis of atlantoaxial joint had been achieved in all 6 patients, with no complications.
Transcranial insertion of atlas screw can be used as a salvage procedure when the conventional method of screw insertion is not possible because of technical difficulties.
Submandibular Approach for Single-Stage Craniovertebral Junction Ventral Decompression and Stabilization: A Preliminary Cadaveric Study of Technical Feasibility
2019, World Neurosurgery
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As reported in posterior surgerical procedures for basilar invagination, the atlantoaxial joints were distracted by placement an intra-articular cage, thus determining odontoid descent and anterior compression reduction. Intraoperative neurophysiologic monitoring is mandatory in these surgical procedures during patient positioning and distraction/decompression maneuvers.32,33 Furthermore, an intra-articular device may improve the possibilities for postsurgical arthrodesis, thus improving the stabilization outcome.
The craniovertebral junction (CVJ) may be affected by several diseases. It is an anatomically complex region, involving the osteoligamentous, vascular, and nervous structures, which makes surgery challenging. In a case of ventral compression, an anterior approach is preferable, although posterior fixation is often required. Anterior transmucosal approaches are associated with high rates of complications. However, decompression and fixation by the use of retropharyngeal extramucosal approaches may be challenging.
To investigate the feasibility of a single-stage, anterior, extramucosal submandibular (SM) approach modification to the CVJ for simultaneous decompression and stabilization.
This was a preliminary cadaveric feasibility study on 2 injected specimens. A variation of the SM approach with a short “boomerang” incision, microsurgical decompression of the ventral CVJ, and a new hybrid construct for an anterior atlantoaxial stabilization was investigated. The surgical approach, the decompression, and the instrumentation technique have been described. In addition, intraprocedural images and radiographs and also postprocedural computed tomographic images were collected. Furthermore, surgical exposure, working corridors and angles, and decompression grade were measured.
The SM approach provided wide exposure of the ventral CVJ and the possibility for instrumentation and decompression by removing the anterior arch of C1 and the odontoid process.
A single- stage anterior extramucosal SM approach for decompression and stabilization of the CVJ is feasible and could result in shorter surgical duration, avoiding the complications related to both the transmucosal approach and the prone position, although specific related risks exist. Mechanical investigation of this hybrid system and in vivo studies are needed to confirm our results.
Characteristics of Cervical Sagittal Alignment at Different C0–C2 Correcting Angles in Fusion Treatment of Atlantoaxial Dislocations
2019, World Neurosurgery
Citation Excerpt :
Matsunaga et al.9 showed that the appropriate range of the C0–C2 correction angle is 0°–30°, as most patients outside this range suffer cervical sagittal malalignment. However, some studies have shown postoperative cervical malalignment within the recommended angle range,7,9,10 which indicates that a C0–C2 correction angle range of 0°–30° might be too large for obtaining the desired cervical alignment. Therefore, the purpose of this study is to explore the appropriate range of C0–C2 correction angles by analyzing cervical sagittal alignment parameters and evaluating clinical outcomes.
To explore the appropriate range of C0–C2 correction angles by analyzing cervical sagittal alignment parameters and evaluating clinical outcomes.
The preoperative and postoperative radiographs, visual analogue scale, Japanese Orthopedic Association score, and neck disability index of 65 atlantoaxial dislocation patients were retrospectively collected. The C0–C2 angle, C2–C7 angle, and cervical sagittal vertical axis (cSVA) were measured from the radiographs, and an assessment of cervical degenerative disc disease was made. According to the 2-year postoperative C0–C2 angles, all patients were categorized into a <10° subgroup, 10°–20° subgroup, and >20° subgroups.
The postoperative C2–C7 angles and cSVA of the 10°–20° subgroup were significantly different from those of the <10° subgroup. The Japanese Orthopedic Association score of the 10°–20° subgroup was significantly different from those of the <10° and >20° subgroups. All patients (26/26) in the 10°–20° subgroup exhibited a cSVA 0–40 mm, 25% of patients (6/24) in the >20° subgroup exhibited a cSVA >40 mm, and 40% of patients (6/15) in the <10° subgroup showed a cSVA <0 mm. The postoperative incidence of cervical degenerative disc disease did not increase in the 10°–20° subgroup.
Atlantoaxial dislocation patients with different C0–C2 postoperative angles had different cervical sagittal alignments and clinical outcomes. In our study, the patients within the C0–C2 10°–20° subgroup exhibited superior clinical outcomes and cervical sagittal alignment.
Anomaly-Related Pathologic Atlantoaxial Displacement in Pediatric Patients
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In recent years, there has been an increasing interest in pathologic/symptomatic atlantoaxial displacement (PAAD) caused by to congenital anomalies of the craniovertebral junction (CVJ).1-5
To analyze clinical and radiologic features of pathologic atlantoaxial displacement (PAAD) in pediatric patients and to compose a treatment algorithm for anomaly-related PAAD.
Criteria of different types of PAAD and treatment algorithms have been widely reported in the literature but are difficult to apply to patients with odontoid abnormalities, C2-C3 block, spina bifida C1, and children.
We evaluated results of treatment of 29 pediatric patients with PAAD caused by congenital anomalies of the craniovertebral junction (CVJ), treated in Ilizarov Center in 2009–2017, including 20 patients with atlantoaxial displacement (AAD) and 9 patients with atlantoaxial rotatory fixation.
There were 14 males (48.3%) and 15 females (51.7%). We singled out 3 groups of patients: nonsyndromic (6 patients, 20.7%), Klippel-Feil syndrome (13 patients, 44.8%), and syndromic (10 patients, 34.5%). Odontoid abnormalities and C1 dysplasia were widely represented in the syndromic group. Local symptoms predominated in the nonsyndromic and KFS groups. In the syndromic group, all patients had AAD and myelopathy. A pronounced decrease of space available for chord C1 and increase of anterior atlantodental interval were noted compared with other groups.
We present a unified treatment algorithm of pediatric anomaly-related PAAD. Syndromic AAD are often accompanied by anterior and central dislocation and myelopathy and atlantooccipital dissociation. These patients require early aggressive surgical treatment. Nonsyndromic and Klippel-Feil syndrome AAD, atlantoaxial subluxation, and atlantoaxial fixation often manifest by local symptoms and need to eliminate CVJ instability. Existing classifications of symptomatic atlantoaxial displacement are not always suitable for patients with CVJ abnormalities.
Biomechanical Study on Atlantoaxial Dislocation Combined with Basilar Invagination by Different Posterior Internal Fixation Methods
2023, Yiyong Shengwu Lixue/Journal of Medical Biomechanics
A radiological study between anterior and posterior surgery in patients with basilar invagination and atlantoaxial dislocation
2022, Chinese Journal of Orthopaedics

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: Conflict of interest statement: This work was supported by the Natural Science Foundation of Guangdong Province, China (Grant 2014A030313600) and the National Natural Science Foundation of China (Grant 81672178). The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

: Sibin Lan, Junjie Xu, and Zenghui Wu contributed equally to this work and should be considered co–first authors.

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Original ArticleAtlantoaxial Joint Distraction for the Treatment of Basilar Invagination: Clinical Outcomes and Radiographic Evaluation

Objective

Methods

Results

Conclusions

Introduction

Section snippets

Patients

Results

Discussion

Conclusions

Clin Neurol Neurosurg

J Orthop Trauma Rehabil

Clinics (Sao Paulo)

Spine J

Complications of transoral and transnasal odontoidectomy: a comprehensive review

Childs Nerv Syst

Posterior occipitocervical reconstruction using cervical pedicle screws and plate-rod systems

Spine (Phila Pa 1976)

Treatment of basilar invagination by atlantoaxial joint distraction and direct lateral mass fixation

J Neurosurg Spine

Irreducible anterior atlantoaxial dislocation: one-stage treatment with a transoral atlantoaxial reduction plate fixation and fusion. Report of 5 cases and review of the literature

Spine (Phila Pa 1976)

Open reduction of irreducible atlantoaxial dislocation by transoral anterior atlantoaxial release and posterior internal fixation

Spine (Phila Pa 1976)

Direct posterior reduction and fixation for the treatment of basilar invagination with atlantoaxial dislocation

Neurosurgery

Distraction, compression, and extension reduction of basilar invagination and atlantoaxial dislocation: a novel pilot technique

Neurosurgery

Treatment of basilar invagination with atlantoaxial dislocation: atlantoaxial joint distraction and fixation with transoral atlantoaxial reduction plate (TARP) without odontoidectomy

Eur Spine J

Significance of occipitoaxial angle in subaxial lesion after occipitocervical fusion

Spine (Phila Pa 1976)

Original Article
Atlantoaxial Joint Distraction for the Treatment of Basilar Invagination: Clinical Outcomes and Radiographic Evaluation