Occipito-cervical fixation in rheumatoid arthritis and posttrauma patients, using the OCAM fixation system. Short report

Occipito-cervical fixation is used in rheumatoid arthritis patients with atlanto-axial subluxation and sub-axial instability or vertical displacement of the odontoid. To date, plates with hooks, wires or screws have been used to achieve internal fixation. We performed a clinical trial with a fixation system that uses bicortical / unicortical occipital clamps and lateral mass / pedicle screws or laminar clamps (OCAM System LFC Poland) for vertical displacement of the odontoid in two rheumatoid arthritis patients and one trauma patient. Material and methods: two women and one man (32 – 81 years) were treated. All 3 patients were intubated awake. They were turned prone into the operating table under fluoroscopic vision. A three point head fixation system was used for stabilization. The foramen magnum was opened and the posterior arch of c1 was removed. Trans-operative neuromonitoring was used in one patient. A rectangular orifice was drilled on both sides of the midline of the occipital bone and the ocam clamps were introduced and rotated so as to secure them between the inner and outer table. Similar holes were drilled bilaterally on c2, c3 or c4 laminas. Clamps were secured either uni or bicortically. Two titanium rods were connected and secured to the clamps. A cancellous rib autograph was used to obtain fusion. Patients were followed clinically and radiographically for at least 6 months (range 6 – 14 months). Results: no immediate postoperative complications were observed. All 3 patients experienced improvement in neck and head pain. All three remained neurologically stable. Conclusion: this preliminary report confirms the usefulness of the ocam system that achieves internal fixation with a straight forward surgical technique that offers the possibility of avoiding the potential complications of lateral mass or pedicular screws with laminar clamps. Longer follow up is needed to draw final conclusions.