Treatment of spinal fractures in ankylosing spondylitis.

Ankylosing spondylitis (AS) is a chronic inflammatory spondyloarthropathy with the potential for progressive spinal stiffness that ultimately makes patients susceptible to spinal fractures with traumatic spinal cord injury from even low-energy trauma. Treatment of patients with AS and spinal fractures (AS+FX) is controversial because, although these patients need especially rigorous stabilization, surgery has been associated with an increased risk of complications and persistent neurological deficits. The purpose of this retrospective case series was to profile patients with AS+FX from a 19-year period within the authors' county hospital system, including differences of neurological status in patients treated operatively vs nonoperatively. The study group comprised 11 patients with AS+FX (9 men and 2 women; mean age, 63 years [range, 38-91 years]). The authors reviewed available clinical notes and imaging reports. Six patients had posterior operative fixation, and 5 were stabilized nonoperatively. By the time of either discharge or final follow-up, 3 of the patients treated operatively deteriorated neurologically (2 of them preoperatively) and 3 remained stable. Of the patients treated nonoperatively, 3 remained neurologically intact, 1 deteriorated, and 1 recovered completely. The most common complications in all patients were pneumonia and urinary tract infection. Operative and nonoperative management produced acceptable outcomes in most patients. The authors recommend individualized treatment, accounting for patient preferences and comorbidities.

Pedicle screw instrumentation of thoracolumbar burst fractures: Biomechanical evaluation of screw configuration with pedicle screws at the level of the fracture.

BACKGROUND: Posterior fixation alone may not be adequate to achieve and maintain burst fracture reduction. Adding screws in the fractured body may improve construct stiffness. This in vitro study evaluates the biomechanical effect of inserting pedicle screws in the fractured body compared with conventional short- and long-segment posterior fixation. METHODS: Stable and unstable L2 burst fractures were created in 8 calf spines (aged 18 weeks). Constructs were tested at 8 Nm in the intact state and then with instrumentation consisting of long- and short-segment posterior fixation with and without screws in the fractured L2 vertebral body after (1) stable burst fracture and (2) unstable burst fracture. Range of motion was recorded at L1-3 for flexion-extension, lateral bending, and axial rotation. Statistical analysis was performed with repeated-measures analysis of variance, with significance set at P < .05. The data were normalized to the intact state (100%). RESULTS: Both long- and short-segment constructs with screws in the fractured body significantly reduced motion compared with the stable and unstable burst fracture in flexion-extension and lateral bending. Fracture screws enhanced construct stability by 68% (on average) relative to conventional short-segment posterior fixation and were comparable to long-segment posterior fixation. CONCLUSIONS: Screws at the fracture level improve construct stiffness. Short-segment constructs may suffice for stable burst fractures. More severe injuries may benefit from fracture screws and can be considered as an alternative treatment to long-segment constructs.

A comparison of film and computer workstation measurements of degenerative spondylolisthesis: intraobserver and interobserver reliability.

STUDY DESIGN: A comparison of measurements of degenerative spondylolisthesis made on film and on computer workstations. OBJECTIVE: To determine whether the 2 methodologies are comparable in some of the parameters used to assess lumbar degenerative spondylolisthesis. SUMMARY OF BACKGROUND DATA: Digital radiology has been replacing analog radiographs. In scoliosis, several studies have shown that measurements made on digital and analog films are similar and that they are also similar to those made on computer workstations. Such work has not been done in spondylolisthesis. METHODS: Twenty-four cases of lumbar degenerative spondylolisthesis were identified from our clinic practice. Three observers measured anterior displacement, sagittal rotation, and lumbar lordosis on digital films using the same protractor and pencil. The same parameters were measured on the same studies at clinical workstations. All measurements were repeated 2 weeks later. A statistician determined the intra and interobserver reliability of the 2 measurement methods and the degree of agreement between the 2 methods. RESULTS: The differences between the first and second readings did reach statistical significance in some cases, but none of them were large enough to be clinically meaningful. The interclass correlation coefficients (ICCs) were >or=0.80 except for one (0.67). The difference among the 3 observers was similarly statistically significant in a few instances but not enough to influence clinical decisions and with good ICCs (0.67 and better). Similarly, the differences in the 2 methods were small, and ICCs ranged from 0.69 to 0.98. CONCLUSION: This study supports the use of computer workstation measurements in lumbar degenerative spondylolisthesis. The parameters used in this study were comparable, whether measured on film or at clinical workstations.

Degenerative spondylolisthesis of the cervical spine: analysis of 58 patients treated with anterior cervical decompression and fusion.

BACKGROUND CONTEXT: Degenerative spondylolisthesis has been well described as a disorder of the lumbar spine. Few authors have suggested that a similar disorder occurs in the cervical spine. To our knowledge, the present study represents the largest series of patients with long-term follow-up who were managed surgically for the treatment of degenerative spondylolisthesis of the cervical spine. PURPOSE: To describe the clinical presentation and radiographic findings associated with degenerative cervical spondylolisthesis, and to report the long-term results of surgically managed patients. STUDY DESIGN: Analysis of 58 patients treated with anterior cervical decompression and fusion for degenerative spondylolisthesis of the cervical spine. PATIENT SAMPLE: From 1974 to 2003, 58 patients were identified as having degenerative spondylolisthesis of the cervical spine occurring in the absence of trauma, systemic inflammatory arthropathy, or congenital abnormality. These patients were identified from a database of approximately 500 patients with degenerative cervical spine disorders treated by the senior one of us. OUTCOME MEASURES: Patient outcomes were evaluated with regard to neurologic improvement (Nurick grade myelopathy) and osseous fusion. METHODS: The records of 58 patients were reviewed. The average follow-up period was 6.9 years (range, 2-24 years). Seventy-two cervical levels demonstrated spondylolisthesis. In all cases, there was radiographic evidence of facet degeneration and subluxation. All patients were treated with anterior cervical decompression and arthrodesis with iliac crest structural graft. This most commonly involved corpectomy of the caudal vertebrae. Three patients required additional posterior facet fusion. RESULTS: Fifty-eight patients demonstrated 72 levels of involvement. The C4-C5 level was most frequently involved (43%). Two radiographically distinct types of listhesis were observed based on the amount of disc degeneration and the degree of spondylosis at adjacent levels. The average neurologic improvement was 1.5 Nurick grades. The overall fusion rate was 92%. Three patients were treated with combined anterior-posterior arthrodesis. The prevalence of myelopathy and instability pattern was greater in the listheses occurring adjacent to spondylotic levels. CONCLUSIONS: Degenerative spondylolisthesis is relatively common in the cervical spine. Common to all cases is facet arthropathy and neurologic compression. Anterior cervical decompression and arthrodesis appears to yield excellent union rates and neurological improvement in those patients having cervical degenerative spondylolisthesis and significant neurological sequelae who have failed nonoperative treatments.

One- and two-level anterior cervical discectomy and fusion: the effect of plate fixation.

BACKGROUND CONTEXT: The success of arthrodesis for anterior cervical fusion depends on several factors, including the number of surgical levels. Internal fixation putatively improves the arthrodesis rate and outcome. PURPOSE: To provide medium-term follow-up data on the surgical success and patient outcome of one- and two-level anterior cervical discectomies and fusions and to determine the effect that plate fixation has on results. STUDY DESIGN: A prospective study of 40 patients who underwent modified Smith-Robinson anterior cervical discectomy and fusion at one or two operative levels. PATIENT SAMPLE: Forty patients. OUTCOME MEASURES: Odom criteria, Nurick grading system, radiographs. METHODS: Forty patients, with an average age of 44 years (range, 27 to 82), were followed for an average of 51 months (range, 24 to 85). All had an anterior discectomy, burring of the end plates and placement of an autogenous tricortical iliac crest graft at one (20 patients) or two levels (20 patients). Twenty-three were stabilized with the Cervical Spine Locking Plate (Synthes Spine, Paoli, PA), 4 single level, 19 two level. All patients had follow-up office visits with examinations and radiographs. Radiographic union, postoperative pain relief and neurologic recovery were evaluated. RESULTS: Successful arthrodesis of single-level procedures occurred in 11 of 16 unplated and 2 of 4 plated fusions. Primary bony union in the two-level group was achieved in 15 of 19 plated patients and did not occur in the single unplated procedure. Clinically, there were 12 excellent, 5 good, 3 satisfactory and 0 poor outcomes among the single-level procedures. Among the dual-level procedures, there were 10 excellent, 5 good, 3 satisfactory and 2 poor results. Nine of 16 who developed adjacent-level degeneration had pain. Five of the 9 also had nonunions. Of the 40, 3 had fibrous union at final follow-up, and 10 had revision surgery. CONCLUSIONS: The Cervical Spine Locking Plate improved the outcome of two-level procedures to that of uninstrumented one-level fusions. Adjacent-level degeneration is associated with persistent pain, especially if there is also a nonunion. Primary bony union is paralleled by a better clinical outcome.