Axis instrumentation: surgical results

Abstract

OBJECTIVE: Evaluate the surgical results of axis screw instrumentation. METHODS: Retrospective evaluation of the clinical and radiological data of patients submitted to axis fixation using screws. RESULTS: Seventeen patients were surgically treated. The mean age was 41.8 years (range: 12-73). Spinal cord trauma was the most common cause of instability (8 patients - 47%). Bilateral axis fixation was performed in all cases, except one, with laminar screw (total of 33 axis screws). Seven patients (41.1%) underwent bilateral pars screws; laminar screws were used in six cases and pedicular screws were used in two. In two cases, we performed a hybrid construction (laminar + pars and pedicle + pars). There was no neurological worsening or death, nor complications directly related to use axis screws. CONCLUSION: Axis instrumentation was effective and safe, regardless of the technique used for stabilization. Based on our learnt experience, we proposed an algorithm to choose the best technique for axis screw fixation.

Axis Screw Fixation – A Step-by-Step Review of the Surgical Techniques

“…11,12 However, if a laminectomy of the axis is necessary for decompressing the spinal cord, obviously C2 laminar screws cannot be used. 1 Additionally, it has the disadvantage of the need to use head screw extension connectors in some cases, since the rods are generally far from the screw head, due to the oblique orientation of the laminar screws compared with subaxial cervical lateral mass screws.…”

“…1,15,16 A midline incision is made in the posterior cervical spine, just below the inion level to the cervical spine. A meticulous subperiosteal dissection is required, as well as exposure of the posterior arch of C1, of the spinous process, the lateral masses and the lamina of the axis.…”

“…1,15,16 A gauze roll is placed in the patient mouth after intubation to allow anteroposterior fluoroscopy if transarticular screws placement is planned, according to the surgeon's preferences. A midline incision is made in the posterior cervical spine, just below the inion level to the subaxial cervical spine.…”

“…1 Additionally, the axis may be included in the spinal instrumentation procedure requiring occipitocervical stabilization or even extension of the subaxial cervical spine surgeries. 1 The classic fixation of the atlantoaxial region, based on wiring Screw-based constructs at C2 have higher rates of fusion and immediate stability, being much more efficient in restricting motion of the atlantoaxial joint than wiring techniques. The most commonly used screw-based fixation techniques of the axis are: laminar, pedicular, pars interarticularis and transarticular C1-2 screws.…”

Surgical treatment of Type II odontoid fractures: anterior odontoid screw fixation or posterior cervical instrumented fusion?

“…[10][11][12] The most common screw fixation techniques are the C1-2 transarticular screw, described by Magerl and Seeman in 1987, as well as C-1 lateral mass screw fixation described by Goel and Laheri, associated with a C-2 screw (lamina, pars, or pedicle). 13,19,20,25 Posterior techniques are indicated when there is a con-traindication for AOSF, such as a reverse fracture line (anteroinferior to posterosuperior of dens base), transverse ligament rupture, nonreducible fractures, nonunions (remote injuries), inappropriate body habitus, severe cervicothoracic kyphosis, and osteoporosis. 1,2,17 Patients in whom postoperative complications such as dysphagia and pneumonia are a concern may instead be indicated for a posterior technique.…”