Spinal surgery

A groundbreaking procedure to address irreducible atlantoaxial dislocation (IAAD) shows promising results according to a new study published in the Journal of Orthopaedic Surgery and Research. As per the study led by Tang Xiangsheng and his team from the Department of Spinal Surgery at the China-Japan Friendship Hospital, Beijing, an innovative endoscopic transnasal anterior release and posterior reduction approach provides a safe and effective treatment for this complex and challenging spinal condition, without the need for an odontoidectomy.

Irreducible atlantoaxial dislocation is a critical and often debilitating condition that affects the pivotal junction between the atlas and axis, the first two cervical vertebrae. Traditional surgical interventions, such as transoral odontoidectomy, although effective, carry significant risks and prolonged recovery times. The new research, DOI: 10.1186/s13018-019-1167-0, investigates the efficacy and safety of the endoscopic technique in managing IAAD.

The Study’s Method and Findings

The study evaluated a series of nine patients with irreducible atlantoaxial dislocation, each of whom underwent the transnasal endoscopic surgery. The patients, aged between 14 and 60 years, presented varying etiologies such as os odontoideum, old traumatic dens fracture, occipitalization of the atlas, and rheumatoid arthritis. The majority underwent C1-C2 pedicle screw fixations, while two required occipitocervical fixation.

Notably, this innovative approach led to complete reduction in eight cases and partial reduction in one. The complication rate was considerably low, with only one superficial infection reported, linked to the posterior approach. Follow-ups over an average span of 17 months confirmed bony fusion in all cases through radiologic assessment, boasting a 100% fusion rate. Importantly, no instances of instrumental failure were recorded during the follow-up period.

The Japanese Orthopedic Association (JOA) score improved significantly, showing an increase from a mean preoperative score of 7.21 to a postoperative score of 12.28. The atlantodontoid interval (ADI) and the cervicomedullary angle (CMA) also saw improvement, cementing the procedure’s success.

Comparative Advantage of the Transnasal Endoscopic Technique

The authors asserted that the transnasal approach offers a reliable alternative to the more conventional transoral surgery. This minimally invasive procedure reduces the potential complications commonly associated with traditional methods. It negates the need for odontoidectomy and circumvents the associated risks, such as infection, excessive bleeding, and prolonged postoperative morbidity. The significant improvement in JOA score and radiological outcomes marks it as an effective solution for patients with IAAD.

Ethical approval for this study was duly obtained from the Medical Ethics Committee of the China-Japan Friendship Hospital, and written informed consent was received from all participants.

Global Relevance of the Study

Atlantaaxial dislocation encompasses a spectrum of disorders leading to instability and potential neurological impairment. The outcomes of the study spearheaded by Xiangsheng and his colleagues are an important contribution to the global body of orthopedic practice, potentially influencing patient care standards worldwide.

Further Research

Though the findings are promising, further long-term studies with larger patient populations are required to validate these outcomes. The procedure’s reproducibility and efficacy across diverse medical facilities also remain to be evaluated.

Implications for Future Surgical Practice

Adopting the transnasal approach could dramatically change how spinal surgeons approach irreducible atlantoaxial dislocation, particularly in cases where traditional surgery poses a high risk for the patient. It may herald a shift towards less invasive, endoscopically-driven procedures in cervical spine surgery.

Keywords 

1. Endoscopic Transnasal Atlantoaxial Dislocation
2. Non-Odontoidectomy IAAD Treatment
3. Minimally Invasive Spinal Surgery
4. Atlantoaxial Dislocation Reduction
5. Innovative Cervical Spine Procedures

References

1. Tang X., Wu X., Tan M., Yi P., Yang F., Hao Q. (2019). Endoscopic transnasal anterior release and posterior reduction without odontoidectomy for irreducible atlantoaxial dislocation. J Orthop Surg Res, 14(1), 119. DOI: 10.1186/s13018-019-1167-0
2. Dickman C.A., Locantro J., Fessler R.G. (1992). The influence of transoral odontoid resection on stability of the craniovertebral junction. J Neurosurg, 77, 525–530. DOI: 10.3171/jns.1992.77.4.0525
3. Wang S., Yan M., Passias P.G., Wang C. (2016). Atlantoaxial rotatory fixed dislocation. Spine (Phila. Pa. 1976), 41, E725–E732. DOI: 10.1097/BRS.0000000000001414
4. Ma H., Dong L., Liu C., Yi P., Yang F., Tang X., et al. (2016). Modified technique of transoral release in one-stage anterior release and posterior reduction for irreducible atlantoaxial dislocation. J Orthop Sci, 21, 7–12. DOI: 10.1016/j.jos.2015.10.012
5. Jiang L., Dong L., Tan M., Yang F., Yi P., Tang X. (2016). Accuracy assessment of atlantoaxial pedicle screws assisted by a novel drill guide template. Arch. Orthop. Trauma Surg, 136, 1483–1490. DOI: 10.1007/s00402-016-2552-y