We describe the clinical results of a technique of direct pars repair stabilised with a construct that consists of a pair of pedicle screws connected with a modular link that passes beneath the spinous process. Tightening the link to the screws compresses the bone grafted pars defect providing rigid intrasegmental fixation.

20 patients aged between 9 and 21 years were included in this prospective study. Each of the patients had high activity levels and suffered from significant back pain without radicular symptoms or signs. Patients had either no or grade I spondylolisthesis. Definitive pseudoarthrosis and fracture were confirmed via computerize tomography (CT). Magnetic resonance imaging was performed in every patient to assess the adjacent disc spaces which demonstrated normal signal intensity.

A midline incision was used for surgery. The pars interarticularis defect was exposed and filled with autologous iliac crest bone graft prior to screw insertion. After screw insertion, a link was contoured to fit, and placed just caudal to the spinous process, deep to the interspinous ligament of the affected level, and attached to each pedicle screw. There was early mobilization post-operatively without a brace. The average inpatient stay was 3 days. Post-operative complications included 1 superficial wound haematoma and two superficial wound infections which responded to antibiotic treatment. Follow-up was at 6 weeks, 6 months and at 18 months, and 24 months. Clinical assessments for all patients was via the Oswestry disability index (ODI) and visual analogue scores (VAS). At the latest follow-up, 18 out of the 20 patients showed a significant (p<0.05) improvement in their ODI and VAS scores. The mean post-operative ODI score was 8%. All patients had radiographs and CT scans which showed fusion rates of 80% in those patients followed up for a minimum of 24 months. This new technique for direct pars repair demonstrates high fusion rates in addition provides the possible benefits of maintaining adjacent level motion. Clinically this group had good-to excellent functional outcomes as indicated by visual analogue scales and the Oswestry Disability Index in 18 out of 20 patients studied with a minimum follow-up of 2 years.

Anterior cervical discectomy and fusion for radiculopathy and myelopathy has the complication of the development of adjacent segment degeneration. Furthermore, reoperations may be required to treat complications of fusion, such as non-union, graft collapse, or expulsion. Cervical disc arthroplasty lays claim to preserving cervical motion and reducing the risks of adjacent segment disease in the treatment of cervical radiculopathy.

We performed a prospective study in order to evaluate the radiological and clinical outcomes of cervical disc arthroplasty for single or two level disc disease with associated radiculopathy. Our study included a total of 26 patients. Each patient had cervical radiculopathy from nerve root compression due to degenerative disc disease at one or two levels. Diagnosis was made preoperatively on clinical examination and by means of MRI scanning. Each patient also had preoperative flexion and extension cervical spine x-rays in order to assess pre-operative range of neck movement.

The outcomes of surgery were assessed prospectively. Range of motion at final follow-up was measured by flexion and extension view x-rays of the cervical spine. Clinical outcome was assessed by means of VAS scores for pain, SF12 for mental and physical health and the neck disability index (NDI). All complications were recorded. 14 of the patients had a follow-up for two years and the remaining 12 patients had a follow-up for one year.

A Discovery disc arthoplasty by Scient'X was the implant used in all patients. A standard anterior cervical approach was used to achieve decompression and for the implantation of the prosthesis.

On follow-up all patients had either maintenance or an improvement in the range of movement. There was no evidence of progression of degeneration in the segments adjacent to the arthroplasty prosthesis. Improvements in SF12, VAS, and NDI scores were seen from preoperative levels in 25 of the 26 patients. Complications included one patient with a horse voice post-operatively and one patient with minimal improvement of radicular symptoms. Post-operative MRI scanning demonstrated adequate decompression with this procedure and showed no evidence of progression of adjacent segment disease. There were no cases of implant subsidence or dislocations.

We have found cervical disc arthroplasty to produce good clinical outcomes when used for single or two level cervical radiculopathy whilst maintaining neck motion with an acceptable complication rate. A longer follow-up is needed to further assess the risk of development of adjacent segment disease but we did not discover the development of adjacent segment disease in our study with a follow-up of upto 2 years