title: Minimally invasive atlantoaxial fusion: cadaveric study and report of 5 clinical cases.
abstract: OBJECTIVE Minimally invasive techniques are being increasingly used to treat disorders of the cervical spine. They have a potential to reduce the postoperative neck discomfort subsequent to extensive muscle dissection associated with conventional atlantoaxial fusion procedures. The aim of this paper was to elaborate on the technique and results of minimally invasive atlantoaxial fusion. MATERIALS Minimally invasive atlantoaxial fusion was done initially in 4 fresh-frozen cadavers and subsequently in 5 clinical cases. Clinical cases included patients with reducible atlantoaxial instability and undisplaced or minimally displaced odontoid fractures. The surgical technique is illustrated in detail. RESULTS Among the cadaveric specimens, all C-1 lateral mass screws were in the correct position and 2 of the 8 C-2 screws had a vertebral canal breach. Among clinical cases, all C-1 lateral mass screws were in the correct position. Only one C-2 screw had a Grade 2 vertebral canal breach, which was clinically insignificant. None of the patients experienced neurological worsening or implant-related complications at follow-up. Evidence of rib graft fusion or C1-2 joint fusion was successfully demonstrated in 4 cases, and flexion-extension radiographs done at follow-up did not show mobility in any case. CONCLUSIONS Minimally invasive atlantoaxial fusion is a safe and effective alternative to the conventional approach in selected cases. Larger series with direct comparison to the conventional approach will be required to demonstrate clinical benefit presumed to be associated with a minimally invasive approach.
authors.affiliation: M. S. Ramaiah Medical College and Hospitals, Bengaluru, Karnataka, India.
authors.forename: Umesh
authors.initials: U
authors.lastname: Srikantha
authors.affiliation: M. S. Ramaiah Medical College and Hospitals, Bengaluru, Karnataka, India.
authors.forename: Kiran S
authors.initials: KS
authors.lastname: Khanapure
authors.affiliation: M. S. Ramaiah Medical College and Hospitals, Bengaluru, Karnataka, India.
authors.forename: Aniruddha T
authors.initials: AT
authors.lastname: Jagannatha
authors.affiliation: M. S. Ramaiah Medical College and Hospitals, Bengaluru, Karnataka, India.
authors.forename: Krishna C
authors.initials: KC
authors.lastname: Joshi
authors.affiliation: M. S. Ramaiah Medical College and Hospitals, Bengaluru, Karnataka, India.
authors.forename: Ravi G
authors.initials: RG
authors.lastname: Varma
authors.affiliation: M. S. Ramaiah Medical College and Hospitals, Bengaluru, Karnataka, India.
authors.forename: Alangar S
authors.initials: AS
authors.lastname: Hegde
mesh_terms: D000328:Adult; D000368:Aged; D001268:Atlanto-Axial Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D001863:Bone Screws; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D005260:Female; D005471:Fluoroscopy; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000295:instrumentation / Q000379:methods*; D013123:Spinal Fusion / Q000295:instrumentation / Q000379:methods*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014741:Video Recording; D055815:Young Adult
keywords: C1–2 fusion; atlantoaxial fusion; cervical; minimal access; minimally invasive spine surgery; tubular retractor