Elsevier

World Neurosurgery

Volume 95, November 2016, Pages 46-52
World Neurosurgery

Original Article
Surgical Treatment of Occipitocervical Dislocation with Atlas Assimilation and Klippel-Feil Syndrome Using Occipitalized C1 Lateral Mass and C2 Fixation and Reduction Technique

https://doi.org/10.1016/j.wneu.2016.07.058Get rights and content

Objective

To introduce and assess a surgical treatment of occipitocervical (OC) dislocation with atlas assimilation and Klippel-Feil syndrome (KFS) using occipitalized C1 lateral mass and C2 fixation and reduction technique.

Methods

From January 2007 to August 2013, 58 symptomatic patients with OC dislocation and KFS of C2-3 congenital fusion and atlas assimilation were surgically treated in our institution via this technique. After opening the C1-2 facet joints via a posterior approach, OC reduction was conducted by intraoperative manipulation and C1 lateral mass and C2 pedicle screw and rod fixation. The instrument position, fusion status, and clinical outcome were analyzed.

Results

The average follow-up was 36 months (range, 18–52 months). Radiologically, effective reduction was achieved in 56 patients (96.6%) and <50% reduction in 2 (3.4%) who had additional transoral decompression. Neurologic improvement and solid bone fusion were achieved in all patients. The clinical symptoms improved for all patients, with the averaged Japanese Orthopedic Association myelopathy scores increasing from 11.5 to 15.6 (P < 0.01).

Conclusions

In patients with OC dislocation and KFS of C2-3 fusion and atlas assimilation, posterior manipulative reduction combined with occipitalized C1 lateral mass and C2 fixation provides a reliable and effective treatment.

Introduction

In 1912, Klippel-Feil syndrome (KFS) was first described with the classic triad of short neck, low posterior hairline, and limited neck motion. This abnormality is the consequence of failed segmentation of the developing sclerotomes during the third to eighth week of gestation.1 KFS of C2-3 fusion and atlas assimilation have congenital fusions at the occiput-C1 and C2-3 junction, resulting in the greatest amount of C1-2 motion and superior odontoid migration.2 The atlantoaxial hypermobility and concomitant basilar invagination (BI) increased the risk of developing neurologic compromise and the need for surgical intervention.2, 3 For this kind of complex abnormalities, occipitocervical (OC) reduction and fixation has been successful in preventing ventral brainstem impingement.4, 5, 6 However, currently available OC fixation devices mainly rely on instrumentation of the occiput. This occipital screw instrumentation has several limitations because of its variable occipital bone thickness and underling vasculature.7, 8, 9

The ideal system for OC fixation should meet the following requirements: 1) it should concern only the involved segments; 2) no hardware should be inserted into the intracalvarium; 3) it should provide immediate reduction of the deformity until fusion develops without requiring postoperative external halo orthoses; and 4) it should be effective even if the laminae are absent.10 Recently, the occipital condyle screw fixation or fused occipital condyle-C1 lateral mass (C1LM) screw fixation in atlas assimilation has been described,11, 12, 13, 14, 15, 16, 17, 18 which could effectively meet all the requirements of an ideal system. To our knowledge, this technique has not been reported in patients with BI and OC dislocation and C2-3 congenital fusion and atlas assimilation. In this study, we use the modified technique of Harms et al.19 and Goel et al.16, 17, 20 and describe this alternative fixation option of occipitalized C1LM and C2 pedicle screw fixation in 58 such patients and to assess this technique.

Section snippets

Patient Population

From January 2007 to August 2013, 58 symptomatic patients with BI and OC dislocation and C2-3 congenital fusion and atlas assimilation were surgically treated in our institution via C1LM and C2 pedicle/pars screw fixation. The patient population comprised 24 males and 34 females, with ages ranging from 14 to 63 years (mean, 30 years). All patients presented with signs and symptoms of spinal cord dysfunction, and surgical stabilization was indicated. There was a history of a minor trauma on the

Results

In all the 58 cases, complete occipitalization of the atlas was found in 48 cases and partial occipitalization of the atlas (C1 superior articular process with/without anterior or posterior arch) was found in 10. According to the KFS classification proposed by Samartzis et al.,21 type I (a single congenitally fused cervical segment) with fused C2-C3 was noted in 49 cases, type II (multiple noncontiguous fused segments) with fused C2-C3 and C5-C6/C6-C7 was noted in 4, and type III (multiple

Discussion

OC dislocation remains as one of the most serious and concerning problems of the craniovertebral junction (CVJ) and can lead to devastating neurologic deficit or death. In KFS of C2-C3 fusion and occipitalization, the deformity makes the level from occiput to C3 only 1 motion segment and leads to greatest OC instability.2, 3 In such conditions, biomechanical complexity of the CVJ and the scarcity of attachment sites on this region have made internal fixation a challenge. Most OC fixation

Conclusions

To address the poor occipital bone purchase and low OC fusion failure rates for the treatment of KFS and occipitalization with BI and OC dislocation, a novel surgical treatment of occipitalized C1LM and C2 fixation has been developed. By intraoperative manipulative reduction and fixation, impaction of the cervicomedullary junction was relieved without anterior decompression. Our results suggest that this technique is feasible and can be considered as a traditional or salvage fixation procedure.

Acknowledgments

This research was supported by the National Natural Science Foundation of China (numbers 81301274 and 81571350) and the Capital Characteristic Clinical Application Research Funding (Z151100004015009).

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    Conflict of interest statement: This research was supported by the National Natural Science Foundation of China (No: 81301274 and 81571350) and the Capital Characteristic Clinical Application Research Funding (Z151100004015009).

    Yi-Heng Yin and Guang-Yu Qiao contributed equally to this work.

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