Treatment Of Atlantoaxial Subluxation Research Articles

Innovative C-Arm-Free Navigation Technique for Posterior Spinal Fixation for Atlantoaxial Subluxation: A Technical Note.

Study design: Technical note. Objectives: To present a novel C-arm-free technique guided by navigation to insert and place a C1 lateral mass screw. Background and Objectives: Atlantoaxial subluxation (AAS) is a relatively common sequelae in patients with rheumatoid arthritis (RA) and upper cervical trauma. If they present with severe symptoms, surgical intervention such as posterior fusion is indicated. The established treatment for AAS is fixation with a C1 lateral mass screw and C2 pedicle screw (modified Goel technique) to achieve bony fusion. However, this technique requires fluoroscopy for C1 screw insertion. To avoid exposing the operating team to radiation, we present here a novel C-arm-free C1 lateral mass screw insertion technique for AAS. Materials and Methods: A 67-year-old man was referred to our hospital with neck pain, quadriparesis, and clumsiness and numbness of both upper and lower limbs. He had undergone C3-6 posterior fusion previously in another hospital. In physical examination, he had severe muscle weakness of bilateral upper limbs and hypoesthesia of all four limbs. He had hyper-reflexia of bilateral lower limbs and pollakiuria. His Japanese orthopedic score was 8 points out of 17. Preoperative radiograms showed AAS with an atlantodental interval (ADI) of 7 mm. MRI indicated retro-odontoid pseudotumor and severe spinal cord compression at the C1-2 level. The patient underwent posterior atlantoaxial fixation under navigation guidance. To prevent epidural bleeding during the insertion and placement of a C1 lateral mass screw, we have here defined a novel screw insertion technique. Results: The surgical time was clocked as 127 min and blood loss was 100 mL. There were no complications per-operatively or in the postoperative period. The patient showed almost full recovery (JOA 16/17) at two months follow-up and a solid bony fusion was noticed in the radiograms at one year follow-up. Conclusions: This novel surgical procedure and C1 lateral mas screw placement technique is a practical and safe method in recent advances of AAS treatment. Procedurally, the technique helps prevent epidural bleeding from the screw entry point and also allows for proper C1 screw insertion under navigation guidance without exposing surgeons and staff to the risk of fluoroscopic radiation.

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P110. The impact of chronic steroid and dmard therapy on atlanto-axial fusion rates in patients with rheumatoid arthritis: a multicenter review

BACKGROUND CONTEXT Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease of the immune system primarily affecting the synovial joints leading to progressive joint destruction with a 1%–2% worldwide prevalence. The cervical spine is commonly affected in patients with RA leading to atlantoaxial subluxation (AAS), basilar invagination (BI), and subaxial subluxation. These patients commonly require stabilization of their AAS requiring either Occipitocervical or C1–C2 arthrodesis. RA has historically been treated with steroid therapy and although this has been falling out of favor with the advent of disease modifying anti-rheumatic drugs (DMARDs); however, some patients are unable to wean from steroids. Although DMARDs have become increasingly popular for treatment of RA there is a growing concern that the cytotoxicity of these agents may compromise wound healing and arthrodesis. Currently there is little information available regarding surgical outcomes in patients on DMARDs. This study aims to identify patients with RA and AAS that underwent surgical intervention. We hypothesize that DMARDS and low dose steroids do not adversely affect patient outcome. PURPOSE To identify the sigficance of impact that chronic steroid and/or DMARD therapy has on RA patients underdoing posterior arthrodesis for atlanto-axial instability. STUDY DESIGN/SETTING Multicenter retrospective review. PATIENT SAMPLE Patients with the diagnosis of RA requiring surgery for atlanto-axial pathology. Patients undergoing occipital–cervical and atlanto-axial arthrodesis were included. OUTCOME MEASURES Primary outcome measure was return to the OR. METHODS This study was a multicentered retrospective review from seven hospitals. All patients with the diagnosis of RA that underwent cervical spine surgery were identified and reviewed. All patients that underwent C1–C2 or occipital–cervical fusion for treatment of AAS dating back to January 2008 were identified and included in the review. Perioperative medications were reviewed for use of steroids, DMARDs, bisphosphonates and hormone therapy. Patients were stratified among 2 groups, those that had their steroids or DMARDs held perioperatively and those that did not. End point measurement was return to the operating room (OR) for wound failure, pseudoarthrosis, infection, or other reasons. RESULTS A total of 40 patients were idenitifed for inclusion in the review. There were two patients in the cohort that required return to the OR, one for pseudoarthrosis and one for wound failure. The patient with pseudoarthrosis maintained their anti-RA medications in the perioperative period while the patient with wound failure had their anti-RA medications held in the perioperative period. There was note however of patients experiencing RA flare-ups when the anti-RA medications were held. CONCLUSIONS Our cohort demonstrated a 5% return to OR rate in RA patients undergoing surgery for atanto-axial instability. There was no demonstrable affect on outcome with respect to holding or continuing anti-RA medications in the peri-operative period in our cohort. The overall affect these medications in this patient population may be benign. However, more studies are warranted to further investigate the impact these medications have in the perioperative period and overall outcome.

The surgical treatment of atlantoaxial subluxation derived from Os odontoiddeum

Objective To summarize the clinical characteristic and the results of surgical treatment of atlantoaxial subluxation patients derived from Os odontoiddeum. Method The clinical materials of 10 cases with Os odontoidum were reviewed and analyzed. Posterior approach atlas and axis pedicle screws or occipital screws and axis pedicle screws were applied to internal fix and fuse the atlas and axis. Before and post operation JOA scores were compared to evaluated the effects of the surgical treatment. Results Average operation time is about 3 hours, no operation related complications happened. The symptoms approved in 8 cases, and kept invariant in 2 cases. Post operation JOA scores were improved significantly. Reduction and bony fusion between atlas and axis were found in all cases 3 months post operation. Conclusions Internal fixation with pedical screws between atlas and axis is safe and effective method to treat Os odontoidum, and approve the symptoms of the patients. Key words: Os odontoidum; Atlas; Dislocations; Neurosurgical procedures

Clinical Study of a Modified Brooks Technique for Atlanto-axial Subluxation Using Polyethylene Tape

Forty-four patients, 15 males and 29 females (3-71 years old; mean age, 52.9), were treated for the control of cervical instability with a modified Brooks operation using Tekmilon tape (an ultrahigh molecular weight polyethylene tape) instead of metal wires. Forty of the patients had rheumatoid arthritis (RA) with atlanto-axial subluxation (AAS), three patients had os odontoideum, and one patient had a cervical spine injury. The mean follow-up period was 8 years and 4 months. These patients were divided into three groups: 30 years or less, 31 to 60 years, and over 60 years. Atlanto-dental interval (ADI), inclination angle of atlanto-axial vertebrae (A-A angle), and bone fusion were examined on plain radiographs. The proportion of patients with reduced neck pain (Ranawat's grade 0 or grade 1) increased from 42.5% to 97.9% at the time of postoperative evaluation. Surgical complications, such as dural tear, lamina fracture, and spinal cord injury did not occur in any cases. Thirty-nine patients (88.6%) achieved bone union. ADI in the maximum flexed position improved from 10.3 to 2.5 mm. There was no statistical difference between ADI in males and females. ADI did not change in any age group both before and after surgery. A-A angle also improved from 9.4 to 24.4 degrees. The polyethylene tapes, used for internal fixation, caused no neurologic complications during sublaminar wiring and produced no MR artifacts. This modified Brooks technique using Tekmilon tape was proved to be a simple and safe treatment of AAS.

Atlantoaxial Fixation using C2 Subarticular Screws and C1 Lateral Mass Screws: A Technical Report

Segmental screw fixation is a useful procedure for the surgical treatment of atlantoaxial subluxation. Currently, C1 lateral mass screws and C2 pedicle screws are the standard screws used in this procedure. However, the C2 pedicle screw can cause serious complications such as vertebral artery injury. Recently we suggested a new trajectory for the C2 screw, the subarticular screw, which has a lower probability of vertebral artery injury compared with the pedicle screw, based on a study using 1 mm-sliced CT scan images and simulation software. We report the first case of segmental screw fixation using C2 subarticular screws along with C1 lateral mass screws. The patient had atlantoaxial subluxation and myelopathy and showed satisfactory results after surgery.

Posterior atlantoaxial transpedicular screw and plate fixation

The authors describe a modified posterior atlantoaxial fixation technique for the treatment of reducible atlantoaxial instability, which can be performed simply and easily, and can decrease the risk of vessel and/or neural damage. During an 18-month period, this technique was undertaken in 11 patients with atlantoaxial instability. There was no procedure-related morbidity. The follow-up period ranged from 8 to 18 months (mean 13.2 months). Fusion was documented in all 11 patients, and there was no progression of spinal deformity. This technique can be considered an effective alternative in the treatment of atlantoaxial subluxation.

A STIFF COLLAR FOR THE TREATMENT OF RHEUMATOID ATLANTOAXIAL SUBLUXATION

Conservative treatment of atlantoaxial subluxation (AAS) has tended to be rather passive, since there has been a lack of effective tools. The stabilizing effect of a stiff collar in the treatment of AAS was evaluated. Fifty successive rheumatoid patients with unstable AAS were interviewed and examined clinically. Lateral view radiographs of the cervical spine were taken in neutral position, during flexion and extension without a collar, and during flexion with a stiff collar. Seventeen patients did not have cervical symptoms. A stiff collar was able to significantly stabilize AAS in more than half of the cases, the effect being predictable from neutral-position radiographs. The improvement in bearing enhanced the effect of the collar. The means and strategy of conservative treatment of AAS are discussed.

Psoriatic arthritis with C-1-C-2 subluxation as a neurosurgical complication

A 39-year-old man presented with a 10-year history of psoriatic arthritis, and more recently a progressive high cervical myelopathy. The development of the myelopathy syndrome was unassociated with trauma or any other specific inciting cause. Cervical spine x-rays demonstrated a significant atlantoaxial subluxation. Other x-ray features of the spine met the criteria for diagnosis of psoriatic spondylitis. The association of a high cervical myelopathy with atlantoaxial subluxation in psoriatic spondylitis is rare. Conversely, atlantoaxial subluxation without high cervical myelopathy has been reported in 45% of cases of psoriatic spondylitis. The authors report this case with a review of the diagnosis, possible pathogenesis, and treatment of atlantoaxial subluxation in psoriatic spondylitis.