Multisegmental Spinal-Shortening Osteotomy for the Treatment of Tethered Cord Syndrome: A Retrospective Study of Six Consecutive Cases

Abstract

Introduction Tethered cord syndrome often presents as low back pain in the early stage and progresses to sensory, motor, bowel, and bladder control dysfunctions. The pathogenesis of tethered cord syndrome is thought to be abnormal longitudinal traction on the caudal end of the spinal cord. Surgical detethering has been considered the gold standard for symptomatic tethered cord syndrome and consistently shown to be effective. However, complications such as cerebrospinal fluid leakage, infection, and neurologic deterioration including motor and bladder function are common. To minimize these complications, vertebral column subtraction osteotomy and pedicle subtraction osteotomy were reported as alternative procedures for the treatment of adult tethered cord syndrome. The concept of the procedures is to reduce neural tension indirectly. We present six consecutive cases with tethered cord syndrome that underwent a modified spinal-shortening osteotomy, which is multisegmental. Materials and Methods We retrospectively reviewed the surgical and radiological data of patients with tethered cord syndrome who underwent multisegmental spinal-shortening osteotomy (MSSO) by one doctor in one of the surgery groups at Changzheng Hospital from July 2009 to July 2013. The average follow-up period was 32 ± 7.5 months. Three patients were male and three were female and the average age at operation was 33 years (range, 16-57 years). MSSO were performed in patients, which required multilevel discectomy and facetectomy. The certain length gap created by the discectomy and facetectomy were then closed with serial compression through the domino connectors. Temporary rods were replaced with permanent rods once final spinal column alignment was achieved. The shortening of the spine was measured at the anterior and posterior borders and the midpoint of the vertebral end plate on the lateral fluoroscopy. Preoperative and postoperative VAS pain scores were evaluated. Results Six patients were followed up for 32 months in average and were included in the analysis. The length of spinal column shortening was 17 ± 1.7 mm. Urinary and sensory dysfunctions (two cases for each) were the most common residual deficits. Two (100%) patients with urological symptoms reported improvements, although deficits remained at the time of last follow-up. Six patients with lower-extremity motor dysfunction improved and six noted complete resolution of preoperative lower-extremity sensory symptoms. Five (100%) reported immediate low back or lower extremity pain relief following MSSO. VAS pain scores of all six patients were greatly improved after surgery. Complete bone union at the osteotomy site was noted in all cases at the time of last follow-up. Conclusion Most of the patients who have undergone MSSO in our study exhibited improvement of urological symptoms, complete recovery of motor functioning, and relief of debilitating back or lower extremity pain. Although many factors preclude a direct comparison of the symptomatic and functional outcomes following traditional surgical detethering compared with MSSO for TCS treatment, the outcomes are grossly similar regarding current literature. We believe that the principal benefits of MSSO over detethering operations will be in preserving the symptomatic and functional neurological improvements with lasting results and potentially obviating the need for future reoperations. However, longer follow-up results are needed from the MSSO series to support this belief. Disclosure of Interest None declared References Agarwalla PK, Dunn IF, Scott RM, Smith ER. Tethered cord syndrome. Neurosurg Clin N Am 2007;18(3):531–547 Alemdaroğlu KB, Atlihan D, Cimen O, Kilinç CY, Iltar S. Morphometric effects of acute shortening of the spine: the kinking and the sliding of the cord, response of the spinal nerves. Eur Spine J 2007;16(9):1451–1457 Hsieh PC, Stapleton CJ, Moldavskiy P, et al. Posterior vertebral column subtraction osteotomy for the treatment of tethered cord syndrome: review of the literature and clinical outcomes of all cases reported to date. Neurosurg Focus 2010;29(1):E6 Kanno H, Aizawa T, Ozawa H, Hoshikawa T, Itoi E, Kokubun S. Spine-shortening vertebral osteotomy in a patient with tethered cord syndrome and a vertebral fracture. Case report. J Neurosurg Spine 2008;9(1):62–66 Kawahara N, Tomita K, Kobayashi T, Abdel-Wanis ME, Murakami H, Akamaru T. Influence of acute shortening on the spinal cord: an experimental study. Spine 2005;30(6):613–620 Kokubun S, Ozawa H, Aizawa T, Ly NM, Tanaka Y. Spine-shortening osteotomy for patients with tethered cord syndrome caused by lipomyelomeningocele. J Neurosurg Spine 2011;15(1):21–27 Miyakoshi N, Abe E, Suzuki T, Kido T, Chiba M, Shimada Y. Spine-shortening vertebral osteotomy for tethered cord syndrome: report of three cases. Spine 2009;34(22):E823-E825 Traynelis VC. Spine shortening of tethered cord. J Neurosurg Spine 2011;15(1):19-20, author reply 20