Objective. To compare the clinical and radiographic outcomes in patients of different ages who underwent the Dynesys stabilization. Methods. This retrospective study included 72 patients (mean age 61.4 years) with one- or two-level lumbar spinal stenosis who underwent laminectomy and the Dynesys (Zimmer Spine, Minneapolis) dynamic stabilization system. Thirty-seven patients were younger than 65-year old while the other 35 were older. Mean followup was 46.7 months. Pre- and postoperative radiographic and clinical evaluations were analyzed. Results. The mean calibrated disc signal (CDS) at the index level was significantly improved from preoperatively to postoperatively ( ). Screw loosening occurred in 22.2% of patients and 5.1% of screws. The improvement in CDS at index level was seen to be significant in younger patients but not in older patients. Overall, the mean visual analogue scale (VAS) of back pain, VAS of leg pain, and the Oswestry disability index (ODI) scores improved significantly after operation. There were no significant differences in pre- and postoperative VAS and ODI and screw loosening rates between the younger and older patients. Conclusions. There is significant clinical improvement after laminectomy and dynamic stabilization for symptomatic lumbar spinal stenosis. Intervertebral disc rehydration was seen in younger patients. 1. Introduction Instrumented spinal fusion is the treatment of choice for degenerative spondylosis with instability refractory to conservative treatment [1, 2]. Spine surgeons have also used modern biologics such as recombinant human bone morphogenetic protein-2 to increase the rate of spinal fusion in selected patients [3–7]. However, using biologics to enhance spinal fusion has been sometimes reported with complications postoperatively and during followup. Moreover, even autograft has been repeatedly reported with adverse events, such as donor site morbidity. Not to mention that loss of segmental motion and subsequent adjacent segmental degeneration have also been concerned for the spinal fusion surgery [8–10]. In the recent years, there is the emerging option of dynamic stabilization to spare spinal fusion and still yield satisfactory outcomes in the surgical management of lumbar spondylosis and back pain. Fischgrund and colleagues reported application of the Dynesys (Zimmer Spine, Minneapolis, USA), a pedicle-based lumbar dynamic stabilization system, as an effective alternative to treat lumbar spondylosis in 1994 [11–16]. Theoretically Dynesys can unload the intervertebral disc while providing a restricted
V. Arlet, L. Jiang, T. Steffen, J. Ouellet, R. Reindl, and M. Aebi, “Harvesting local cylinder autograft from adjacent vertebral body for anterior lumbar interbody fusion: surgical technique, operative feasibility and preliminary clinical results,” The European Spine Journal, vol. 15, no. 9, pp. 1352–1359, 2006.
K. H. Bridwell, T. A. Sedgewick, M. F. O'Brien, L. G. Lenke, and C. Baldus, “The role of fusion and instrumentation in the treatment of degenerative spondylolisthesis with spinal stenosis,” Journal of Spinal Disorders, vol. 6, no. 6, pp. 461–472, 1993.
Z. Ghogawala, E. C. Benzel, S. Amin-Hanjani et al., “Prospective outcomes evaluation after decompression with or without instrumented fusion for lumbar stenosis and degenerative Grade I spondylolisthesis,” Journal of Neurosurgery, vol. 1, no. 3, pp. 267–272, 2004.
H. N. Herkowitz and L. T. Kurz, “Degenerative lumbar spondylolisthesis with spinal stenosis: a prospective study comparing decompression with decompression and intertransverse process arthrodesis,” Journal of Bone and Joint Surgery A, vol. 73, no. 6, pp. 802–808, 1991.
A. R. Vaccaro, D. G. Anderson, T. Patel et al., “Comparison of OP-1 putty (rhBMP-7) to iliac crest autograft for posterolateral lumbar arthrodesis: a minimum 2-year follow-up pilot study,” Spine, vol. 30, no. 24, pp. 2709–2716, 2005.
A. ？akmak, A. Gyedu, I. Kepenek？i, C. ？zcan, and A. E. ünal, “Colon perforation caused by migration of a bone graft following a posterior lumbosacral interbody fusion operation: case report,” Spine, vol. 35, no. 3, pp. E84–E85, 2010.
J. S. Fischgrund, M. Mackay, H. N. Herkowitz, R. Brower, D. M. Montgomery, and L. T. Kurz, “Degenerative lumbar spondylolisthesis with spinal stenosis: a prospective, randomized study comparing decompressive laminectomy and arthrodesis with and without spinal instrumentation,” Spine, vol. 22, no. 24, pp. 2807–2812, 1997.
D. Grob, A. Benini, A. Junge, and A. F. Mannion, “Clinical experience with the dynesys semirigid fixation system for the lumbar spine: surgical and patient-oriented outcome in 50 cases after an average of 2 years,” Spine, vol. 30, no. 3, pp. 324–331, 2005.
S. Schaeren, I. Broger, and B. Jeanneret, “Minimum four-year follow-up of spinal stenosis with degenerative spondylolisthesis treated with decompression and dynamic stabilization,” Spine, vol. 33, no. 18, pp. E636–E642, 2008.
K. J. Schnake, S. Schaeren, and B. Jeanneret, “Dynamic stabilization in addition to decompression for lumbar spinal stenosis with degenerative spondylolisthesis,” Spine, vol. 31, no. 4, pp. 442–449, 2006.
T. M. Stoll, G. Dubois, and O. Schwarzenbach, “The dynamic neutralization system for the spine: a multi-center study of a novel non-fusion system,” The European Spine Journal, vol. 11, no. 2, pp. S170–S178, 2002.
J. C. Wu, W. C. Huang, H. W. Tsai, C. C. Ko, C. L. Wu, T. H. Tu, et al., “Pedicle screw loosening in dynamic stabilization: incidence, risk, and outcome in 126 patients,” Neurosurgical Focus, vol. 31, no. 4, article E9, 2011.
A. G. Copay, S. D. Glassman, B. R. Subach, S. Berven, T. C. Schuler, and L. Y. Carreon, “Minimum clinically important difference in lumbar spine surgery patients: a choice of methods using the Oswestry Disability Index, Medical Outcomes Study questionnaire Short Form 36, and Pain Scales,” Spine Journal, vol. 8, no. 6, pp. 968–974, 2008.
J. N. Weinstein, J. D. Lurie, T. D. Tosteson et al., “Surgical compared with nonoperative treatment for lumbar degenerative spondylolisthesis: four-year results in the Spine Patient Outcomes Research Trial (SPORT) randomized and observational cohorts,” Journal of Bone and Joint Surgery A, vol. 91, no. 6, pp. 1295–1304, 2009.
R. A. Deyo, D. C. Cherkin, J. D. Loeser, S. J. Bigos, and M. A. Ciol, “Morbidity and mortality in association with operations on the lumbar spine. The influence of age, diagnosis, and procedure,” Journal of Bone and Joint Surgery A, vol. 74, no. 4, pp. 536–543, 1992.
M. Y. Wang, B. A. Green, S. Shah, S. Vanni, and A. D. Levi, “Complications associated with lumbar stenosis surgery in patients older than 75 years of age,” Neurosurgical Focus, vol. 14, no. 2, article e7, 2003.
M. Putzier, S. V. Schneider, J. F. Funk, S. W. Tohtz, and C. Perka, “The surgical treatment of the lumbar disc prolapse: nucleotomy with additional transpedicular dynamic stabilization versus nucleotomy alone,” Spine, vol. 30, no. 5, pp. E109–E114, 2005.
C. C. Würgler-Hauri, A. Kalbarczyk, M. Wiesli, H. Landolt, and J. Fandino, “Dynamic neutralization of the lumbar spine after microsurgical decompression in acquired lumbar spinal stenosis and segmental instability,” Spine, vol. 33, no. 3, pp. E66–E72, 2008.
S. Vaga, M. Brayda-Bruno, F. Perona et al., “Molecular MR imaging for the evaluation of the effect of dynamic stabilization on lumbar intervertebral discs,” The European Spine Journal, vol. 18, no. 1, supplement, pp. S40–S48, 2009.