Sagittal reconstruction of the atlantoaxial lateral mass complex with an intra-articular cage fusion technique for degenerative atlantoaxial instability

OBJECTIVE

To evaluate the outcomes of sagittal reconstruction of the atlantoaxial lateral mass complex using a modified intra-articular cage fusion technique for treating degenerative atlantoaxial instability (AAI).

METHODS

Data from 15 patients with degenerative AAI were retrospectively reviewed. All patients underwent posterior reduction and intra-articular fusion with a cage filled with local autologous bone. The atlanto-dental interval (ADI) values on plain radiograph in flexion before and after operation were recorded. Bone fusion was evaluated on computed tomography (CT) reconstruction and bone fusion time was recorded. The lateral atlantoaxial joint space height (LAAJSH) before and after surgery was measured on coronal CT reconstruction. Japanese Orthopedic Association (JOA) score and visual analog scale score for neck pain (VASSNP) before surgery and at the final follow up were compared.

RESULTS

The mean follow up time was 40.7±13.4 months. All patients achieved good reduction and solid bone fusion at follow-up. The mean fusion time was 4.4±1.1 months. The ADI decreased from 8.6±1.5 mm preoperatively to 1.9±0.5 mm at the final follow up (P<0.05). The LAAJSH significantly improved from 1.7±0.5 preoperatively to 4.7±0.3 at the final follow-up (P<0.05). The JOA score significantly improved from 14.9±1.5 preoperatively to 16.7±0.6 at the final follow-up (P<0.05). The VASSNP markedly decreased from 4.5±1.8 preoperatively to 0.5±0.6 at the final follow-up (P<0.05).

CONCLUSIONS

Posterior reduction and intra-articular cage fusion with a C2 nerve root preservation technique is effective in the treatment of degenerative AAI. It can well reconstruct the sagittal alignment and the height of atlantoaxial complex.

One-Stage Anterior Retropharyngeal Release Followed by Posterior Open Reduction and Intra-Articular Cage Fusion for Treating Chronic Fixed Type III Atlantoaxial Rotatory Fixation

OBJECTIVE

To verify the effectiveness of anterior retropharyngeal release followed by posterior open reduction using long arm reduction screws combined with intra-articular fusion with a cage filled with the local autologous bone for treating fixed Type III atlantoaxial rotatory fixation (AARF).

METHODS

Data from 6 children with fixed AARF were retrospectively reviewed. All patients underwent anterior retropharyngeal release followed by posterior open reduction using long-arm reduction screws combined with intra-articular fusion with a cage filled with local autologous bone. Outcomes were measured using the atlantodental interval value, the Japanese Orthopedic Association score and visual analog scale for neck pain. Patient age, sex, operation time, blood loss, and bone fusion time were recorded. Complications related to the operation were also recorded.

RESULTS

All patients achieved complete reduction and solid bone fusion at follow-up. The atlantodental interval dropped to 2.1 ± 0.5 mm after the operation from a preoperative score of 15.3 ± 3.1 mm (P < 0.05). Japanese Orthopedic Association score significantly improved from a preoperative score of 15.3 ± 0.5 to 17 ± 0 at the final follow-up (P < 0.05). Visual analog scale for neck pain markedly decreased from preoperative 4.5 ± 1.0 to 0.2 ± 0.4 at the final follow-up (P < 0.05). No complication related to the surgical approach or instrumentation was observed.

CONCLUSIONS

One-stage anterior retropharyngeal release followed by posterior open reduction combined with intra-articular cage fusion is effective in treating chronic fixed type III AARF.

[The Facet Wedge: a minimally invasive technique for posterior segmental intra-articular fusion]

OBJECTIVE

Minimally invasive posterior segmental instrumentation and intra-articular fusion with the Facet Wedge device.

INDICATIONS

All fusion indications in degenerative disc disease without significant translational instability, postnucleotomy syndrome, spondylarthrosis, discitis.

CONTRAINDICATIONS

Translatory instabilities, status after decompression with partial facet joint resection, spondylolysis in the affected segment.

SURGICAL TECHNIQUE

Through a 3 cm skin incision, blunt transmuscular approach to the corresponding facet joint L1/2 to L5/S1. Opening of the joint capsule and visualisation of the intra-articular space. Cartilage removal and intra-articular implantation of the Facet Wedge device. Fixation of the implant by means of two angle-stable screws inserted in the corresponding facet joint parts.

POSTOPERATIVE MANAGEMENT

Early mobilisation under thomboprophylaxis. Wearing a trunk-stabilizing brace for up to 12 weeks, depending on the type and extent of the procedure. No restrictions regarding walking distance, standing and sitting immediately postoperatively after pain.

RESULTS

In all, 27 patients (mean age 51.2 years, range 30-76 years) were enrolled in the prospective nonrandomized study from 02/2015 to 9/2017 with a total of 31 treated segments. In 23 cases a ventrodorsal surgical technique was used, in 4 cases a purely dorsal procedure with interposition of an intervertebral cage. Follow-up was 2 years. The Oswestry Score (ODI) improved from an average of 40.6% preoperatively to 16.6% postoperatively. The visual analog scale (VAS) for back pain improved from an average of 6.7 points preoperatively to 2.1 points 2 years postoperatively. During this observation period, 2 implant-specific complications were observed. One Facet Wedge had to be revised due to misplacement with early loosening. In another case, loss of correction occurred in a preoperatively existing first-degree spondylolisthesis with revision to a dorsal screw-rod system.