Douglas Wardlaw

Efficacy and safety of balloon kyphoplasty compared with non-surgical care for vertebral compression fracture (FREE): a randomised controlled trial

BACKGROUND Balloon kyphoplasty is a minimally invasive procedure for the treatment of painful vertebral fractures, which is intended to reduce pain and improve quality of life. We assessed the efficacy and safety of the procedure. METHODS Adults with one to three acute vertebral fractures were eligible for enrolment in this randomised controlled trial at 21 sites in eight countries. We randomly assigned 300 patients by a computer-generated sequence to receive kyphoplasty treatment (n=149) or non-surgical care (n=151). The primary outcome was the difference in change from baseline to 1 month in the short-form (SF)-36 physical component summary (PCS) score (scale 0-100) between the kyphoplasty and control groups. Quality of life and other efficacy measurements and safety were assessed up to 12 months. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00211211. FINDINGS 138 participants in the kyphoplasty group and 128 controls completed follow-up at 1 month. By use of repeated measures mixed effects modelling, all 300 randomised participants were included in the analysis. Mean SF-36 PCS score improved by 7.2 points (95% CI 5.7-8.8), from 26.0 at baseline to 33.4 at 1 month, in the kyphoplasty group, and by 2.0 points (0.4-3.6), from 25.5 to 27.4, in the non-surgical group (difference between groups 5.2 points, 2.9-7.4; p<0.0001). The frequency of adverse events did not differ between groups. There were two serious adverse events related to kyphoplasty (haematoma and urinary tract infection); other serious adverse events (such as myocardial infarction and pulmonary embolism) did not occur perioperatively and were not related to procedure. INTERPRETATION Our findings suggest that balloon kyphoplasty is an effective and safe procedure for patients with acute vertebral fractures and will help to inform decisions regarding its use as an early treatment option.

Qualitative grading of severity of lumbar spinal stenosis based on the morphology of the dural sac on magnetic resonance images.

Study Design. Retrospective radiologic study on a prospective patient cohort. Objective. To devise a qualitative grading of lumbar spinal stenosis (LSS), study its reliability and clinical relevance. Summary of Background Data. Radiologic stenosis is assessed commonly by measuring dural sac cross-sectional area (DSCA). Great variation is observed though in surfaces recorded between symptomatic and asymptomatic individuals. Methods. We describe a 7-grade classification based on the morphology of the dural sac as observed on T2 axial magnetic resonance images based on the rootlet/cerebrospinal fluid ratio. Grades A and B show cerebrospinal fluid presence while grades C and D show none at all. The grading was applied to magnetic resonance images of 95 subjects divided in 3 groups as follows: 37 symptomatic LSS surgically treated patients; 31 symptomatic LSS conservatively treated patients (average follow-up, 2.5 and 3.1 years); and 27 low back pain (LBP) sufferers. DSCA was also digitally measured. We studied intra- and interobserver reliability, distribution of grades, relation between morphologic grading and DSCA, as well relation between grades, DSCA, and Oswestry Disability Index. Results. Average intra- and interobserver agreement was substantial and moderate, respectively (k = 0.65 and 0.44), whereas they were substantial for physicians working in the study originating unit. Surgical patients had the smallest DSCA. A larger proportion of C and D grades was observed in the surgical group. Surface measurements resulted in overdiagnosis of stenosis in 35 patients and under diagnosis in 12. No relation could be found between stenosis grade or DSCA and baseline Oswestry Disability Index or surgical result. C and D grade patients were more likely to fail conservative treatment, whereas grades A and B were less likely to warrant surgery. Conclusion. The grading defines stenosis in different subjects than surface measurements alone. Since it mainly considers impingement of neural tissue it might be a more appropriate clinical and research tool as well as carrying a prognostic value.

Balloon kyphoplasty for the treatment of acute vertebral compression fractures: 2‐year results from a randomized trial

Vertebral fractures are often painful and lead to reduced quality of life and disability. We compared the efficacy and safety of balloon kyphoplasty to nonsurgical therapy over 24 months in patients with acute painful fractures. Adults with one to three vertebral fractures were randomized within 3 months from onset of pain to undergo kyphoplasty (n = 149) or nonsurgical therapy (n = 151). Quality of life, function, disability, and pain were assessed over 24 months. Kyphoplasty was associated with greater improvements in Short‐Form 36 (SF‐36) Physical Component Summary (PCS) scores when averaged across the 24‐month follow‐up period compared with nonsurgical therapy [overall treatment effect 3.24 points, 95% confidence interval (CI) 1.47–5.01, p = .0004]; the treatment difference remained statistically significant at 6 months (3.39 points, 95% CI 1.13–5.64, p = .003) but not at 12 months (1.70 points, 95% CI −0.59 to 3.98, p = .15) or 24 months (1.68 points, 95% CI −0.63 to 3.99, p = .15). Greater improvement in back pain was observed over 24 months for kyphoplasty (overall treatment effect −1.49 points, 95% CI −1.88 to −1.10, p < .0001); the difference between groups remained statistically significant at 24 months (−0.80 points, 95% CI −1.39 to −0.20, p = .009). There were two device‐related serious adverse events in the second year that occurred at index vertebrae (a spondylitis and an anterior cement migration). There was no statistically significant difference between groups in the number of patients (47.5% for kyphoplasty, 44.1% for control) with new radiographic vertebral fractures; fewer fractures occurred (∼18%) within the second year. Compared with nonsurgical management, kyphoplasty rapidly reduces pain and improves function, disability, and quality of life without increasing the risk of additional vertebral fractures. The differences from nonsurgical management are statistically significant when averaged across 24 months. Most outcomes are not statistically different at 24 months, but the reduction in back pain remains statistically significant at all time points.

The Dynesys lumbar spinal stabilization system: a preliminary report on positional magnetic resonance imaging findings.

Study Design. We present the positional magnetic resonance imaging findings of a prospective case series of patients undergoing surgery with the Dynesys spinal stabilization device (Zimmer, Inc., Warsaw, IN). Objective. To explore the biomechanical impact of the Dynesys device in vivo. Summary of Background Data. Spinal fusion surgery is widely used for painful degenerative conditions of the lumbar spine that have not responded to conservative measures. It often produces good outcomes but can be associated with adjacent segment hypermobility that may lead to further degeneration and pain. Previous cadaveric biomechanical studies claim that the Dynesys Dynamic Spinal Stabilization System allows some lumbar movement, behaving similar to a normal spine in extension but similar to rigid fixation in flexion. Methods. Twenty-four patients with dominant low back pain, with or without leg pain, were treated with the Dynesys. All patients underwent positional magnetic resonance imaging before surgery and 9 months after surgery. Measurements were made to assess the differences at the operated level, adjacent level, and whole lumbar spine. Results. There was a statistically significant reduction in flexion-extension range of movement of both the whole lumbar spine by 13.37° (P = 0.002) and at the instrumented segments by 4.08° (P < 0.001) following surgery. There was an insignificant reduction in range of movement at the level above instrumentation (P = 0.807). Mean anterior disc height at the instrumented level reduced by 0.7 mm following insertion of the Dynesys (P < 0.027). Mean posterior disc height reduced by 0.3 mm (P = 0.453). In a neutral posture, the Dynesys had no significant impact on lordosis or inclination of operated or adjacent levels. Contrary to cadaveric study findings, the Dynesys appears to restrict extension more than flexion with respect to a neutral posture. Conclusions. In vivo, the Dynesys Stabilization System allows movement at the instrumented level, albeit reduced, with no significant increased mobility at the adjacent segments. There was reduction of the anterior disc height without a significant increase of the posterior disc height.

One-year results of X STOP interspinous implant for the treatment of lumbar spinal stenosis

Study Design. Prospective observational study. Objective. To prospectively assess the clinical outcome of patients with symptomatic lumbar spinal stenosis before and at periodic intervals after X Stop implantation and to compare the data with previous studies. Summary of Background Data. The X Stop Interspinous Process Distraction Device is a relatively new interspinous implant designed for patients with symptomatic spinal stenosis particularly neurogenic claudication. Previously, a randomized study has shown a 75% improvement in symptoms and physical function at 1-year post-X Stop implantation for lumbar spinal stenosis. The only other study is a preliminary report of only 10 patients with variable intervals of clinical outcome assessment. Method. Forty consecutive patients were enrolled and surgically treated with X Stop implantation. The X Stop device was implanted at the stenotic segment, which was either at 1 or 2 levels in each patient. They were clinically evaluated at the preoperative, 3-month, 6-month, and 1-year stage with clinical questionnaires (Zurich Claudication Questionnaire, Oswestry Disability Index, and SF-36). Results. Sixteen patients failed to complete all the questionnaires at all time intervals and hence were excluded, leaving 24 patients who had completed all questionnaire at all time interval. By 12 months, 54% of these 24 patients reported clinically significant improvement in their symptoms, 33% reported clinically significant improvement in physical function, and 71% expressed satisfaction with the procedure. 29% of the patients required caudal epidural after 12 months after surgery for recurrence of their symptoms of neurogenic claudication. Conclusion. The results of this prospective observational study indicate that X Stop offers significant short-term improvement over a 1-year period. It is a safe, effective, and less invasive alternative for treatment of lumbar spinal stenosis. Our results, however, are less favorable than the previous multicenter, randomized study.

Allograft Versus Autograft in Instrumented Posterolateral Lumbar Spinal Fusion : A Randomized Control Trial

Study Design. To evaluate the clinical outcome respective of the type of bone graft used, 69 patients undergoing instrumented lumbar spinal fusion were randomized to receive either their own bone (harvested from the iliac crest) or allograft bone (fresh-frozen femoral head from donors undergoing total hip joint arthroplasty). Self-completed questionnaires were administered before surgery and at intervals thereafter. Objectives. To compare the clinical outcome of lumbar spinal fusion carried out using either allograft or autograft bone. Summary of Background Data. Previous studies have suggested that allograft bone is effective in cervical and thoracic fusion operations but that it is less effective in lumbar spinal fusions. Most of these studies used a radiographic means of determining fusion. However, no reliable radiologic assessment method has yet been agreed upon. It has also been shown that radiographic appearance does not correlate with clinical outcome. Methods. A total of 69 patients undergoing instrumented posterolateral lumbar spinal fusion surgery were randomized to receive either allograft bone from the North East of Scotland Blood Transfusion Service or autologous bone from the iliac crest. The patients were then followed up at 1-year intervals over 6 years regarding clinical outcome. Results. Patients receiving allograft bone had outcome scores similar to those who had received their own bone, except that in the autograft group there was a significant incidence of donor site pain that was persistent in about one sixth of patients. Conclusions. Allograft bone, in the form of fresh-frozen human femoral head, gives clinical results at least as good as autograft bone in instrumented posterolateral lumbar spinal fusion and completely avoids any donor site complications.

The Positional Magnetic Resonance Imaging Changes in the Lumbar Spine Following Insertion of a Novel Interspinous Process Distraction Device

Study Design. Patients with symptomatic lumbar spinal stenosis underwent magnetic resonance imaging to study changes in the lumbar spine in various postures before and after implantation of the X STOP Interspinous Process Distraction Device (St. Francis Medical Technologies, Concord, CA). Objective. To visualize the effect of the device in vivo. Summary of Background Data. Previous studies have shown vertebral canal and exit foraminal area to reduce from flexion to extension. Recently, reports on improved kinematics in vitro at the implantation level of the X STOP device have also been published. Methods. Using positional magnetic resonance imaging, patients were scanned before and 6 months after surgery. Images were taken with the patient in sitting flexed, extended, neutral, and standing positions. The total range of motion of the lumbar spine and individual segments were measured, along with changes in disc height, areas of the exit foramens, and dural sac. Results. In 12 patients with 17 distracted levels, the area of the dural sac at these levels increased from 77.8 to 93.4 mm2 after surgery in the standing position (P = 0.006), with increase in the exit foramens, but no change in lumbar posture. Conclusions. This study shows that the X STOP device increases the cross-sectional area of the dural sac and exit foramens without causing changes in posture.

Disc changes in the bridged and adjacent segments after Dynesys dynamic stabilization system after two years.

Study Design. Prospective case series. Objective. To study the radiologic changes in the intervertebral disc after Dynesys dynamic stabilization. Summary of Background Data. Adjacent segment disc degeneration is one of the potential complications of fusion surgery. It has been proposed that nonfusion motion preservation surgery may prevent accelerated adjacent segment degeneration because of the protective effect of persisting segmental motion. Methods. Thirty-two patients who underwent Dynesys procedure between November 2002 and June 2004 and have completed 2-year follow-up MRI scans were included in this study. Preoperative and 2 year postoperative lumbar MRI scans were evaluated by 2 independent observers. T2-weighted mid-sagittal images were used and disc degeneration classified according to the Woodend classification of disc degeneration. Anterior and posterior intervertebral disc heights were also measured. Results. Of the 32 patients, 20 patients underwent Dynesys procedure alone and 12 underwent additional fusion at 1 or more levels. A total of 70 levels were operated on, of which 13 levels were fused. There was a statistically significant increase in the mean Woodend score at the operated levels in the Dynesys alone group, a change from 1.95 before surgery to 2.52 after surgery (P < 0.001). The mean Woodend scores changed from 1.27 preoperative to 1.55 postoperative (P = 0.066) at the proximal adjacent levels, and from 1.37 to 1.62 at the distal levels (P = 0.157). There was good interobserver agreement (weighted &kgr; score of 0.819). The anterior intervertebral disc height reduced by 2 mm from 9.25 to 7.17 (P < 0.001). The posterior disc height increased by 0.14 mm but this change was not significant. Conclusion. Disc degeneration at the bridged and adjacent segment seems to continue despite Dynesys dynamic stabilization. This continuing degeneration could be due to natural disease progression.

Influence of X Stop on Neural Foramina and Spinal Canal Area in Spinal Stenosis

Study Design. Measurements of cross sections of exit foramen and spinal canal were performed before and after placement of X Stop in physiologic postures using positional MR scanner at the stenosed level in patients with lumbar spinal stenosis. Objective. To quantify the effect of the implant in vivo on the lumbar spine at the instrumented levels in various postures. Summary of Background Data. Dimensions of the spinal canal and neural foramen decrease from flexion to extension. Symptoms of spinal stenosis occur typically in standing or extension. The X Stop device is designed to distract the posterior elements of the stenotic segment and place it in flexion to treat neurogenic claudication. We think that the device will improve the dimension of the canal in standing and extension. Methods. Twenty-six patients with lumbar spine stenosis underwent a one- or two-level X Stop procedure. All had preoperative and postoperative positional MRI in standing, supine, and sitting flexion and extension. Measurements were carried out on the images acquired. Results. Significant increase in the dimensions of the neural foramen and canal area were demonstrated after surgery. Conclusions. The X Stop device improves the degree of central and foraminal stenosis in vivo.

Effects of X-STOP device on sagittal lumbar spine kinematics in spinal stenosis.

The X-Stop device is designed to distract the posterior elements of the stenotic segment and place it in flexion to treat neurogenic claudication. Previous biomechanical studies on X Stop have been done in vitro on cadavers looking at disc pressures and segmental range of movements. The objective of this study is to understand the sagittal kinematics in vivo of the lumbar spine at the instrumented and adjacent levels. Twenty-six patients with lumbar spine stenosis underwent 1 or 2 level X-Stop procedure. All had pre- and postoperative positional magnetic resonance imaging (MRI) in standing, supine, and sitting in flexion and extension. Measurements of disc heights, endplate angles, segmental and lumbar range of movement were performed after placement of X Stop at the stenosed level in patients with lumbar spinal stenosis. No significant changes were seen in disc heights, segmental and total lumbar spine movements postoperatively. The X-Stop device does not affect the sagittal kinematics of the lumbar spine in vivo.