Microsurgical bilateral decompression via a unilateral approach for lumbar spinal canal stenosis including degenerative spondylolisthesis

Clinical article

Restricted access


Surgical outcome and radiographic changes after microsurgical bilateral decompression via a unilateral approach (MBDU) for lumbar spinal canal stenosis during midterm follow-up periods (> 2 years) have not been reported. The authors retrospectively investigated surgical outcomes after MBDU in patients with lumbar degenerative spondylolisthesis with stenosis in comparison with patients with degenerative stenosis during a minimum follow-up period of 2 years. Radiographic changes at the affected intervertebral level were analyzed during that follow-up period.


Forty-eight patients (23 in the spondylolisthesis group, 25 in the degenerative stenosis group) were included in the study. The average follow-up period was 46 months (range 24–71 months). Surgical outcome was evaluated using the Neurogenic Claudication Outcome Score (NCOS) and the Oswestry Disability Index (ODI). Additionally, the back pain score within the NCOS was also compared. There were no statistically significant differences between the spondylolisthesis group and the degenerative stenosis group with regard to sex, age, follow-up period, operating time, blood loss, surgical sites, approach side, preoperative NCOS, preoperative back pain score, and preoperative ODI. Comparisons were also made between groups using 2 satisfaction measurements at the last follow-up visit. Radiographically, intervertebral angles of 80 sites and slip percentages of 24 sites were measured preoperatively and at the last follow-up.


No patient in either group had additional surgery in the lumbar spine, including fusion procedures. The NCOS, back pain score, and ODI had significantly improved at the last follow-up in both groups. There were no significant differences between the 2 groups in these 3 parameters and the 2 satisfaction measurements at the last follow-up, although those for the spondylolisthesis group indicated a somewhat worse outcome. Intervertebral angles, dynamic intervertebral angles, and dynamic slip percentage did not significantly change after surgery, whereas only slip percentage significantly increased postoperatively (p = 0.0319).


A satisfactory outcome of MBDU persisted for a period longer than 2 years for patients with degenerative spondylolisthesis with stenosis as well as for those with degenerative stenosis. Radiographically in both groups this less invasive procedure was not likely to result in postoperative dynamic instability at the affected level, although the slippage progressed in the spondylolisthesis group.

Abbreviations used in this paper: LSCS = lumbar spinal canal stenosis; MBDU = microsurgical bilateral decompression via a unilateral approach; NCOS = Neurogenic Claudication Outcome Score; ODI = Oswestry Disability Index.
Article Information

Contributor Notes

Address correspondence to: Kunihiko Sasai, M.D., Ph.D., Department of Orthopedic Surgery, Kansai Medical University, 2-3-1 Shinmachi, Hirakata City, Osaka, 573-1191, Japan. email: sasaik@hirakata.kmu.ac.jp.
  • 1

    Fujiwara AKobayashi NSaiki KKitagawa TTamai KSaotome K: Association of the Japanese Orthopaedic Association score with the Oswestry Disability Index, Roland-Morris Disability Questionnaire, and short-form 36. Spine 28:160116072003

    • Search Google Scholar
    • Export Citation
  • 2

    Greenough CGFraser RD: Assessment of outcome in patients with low-back pain. Spine 17:36411992

  • 3

    Matsunaga SIjiri KHayashi K: Nonsurgically managed patients with degenerative spondylolisthesis: a 10-to 18-year follow-up study. J Neurosurg 93:2 Suppl1941982000

    • Search Google Scholar
    • Export Citation
  • 4

    McCulloch JAMicrosurgical spinal laminotomies. Frymoyer JW: The Adult Spine: Principles and Practice New YorkRaven Press, Ltd1991. 18211831

    • Search Google Scholar
    • Export Citation
  • 5

    Palmer STurner RPalmer R: Bilateral decompression of lumbar spinal stenosis involving a unilateral approach with microscope and tubular retractor system. J Neurosurg 97:2 Suppl2132172002

    • Search Google Scholar
    • Export Citation
  • 6

    Palmer STurner RPalmer R: Bilateral decompressive surgery in lumbar spinal stenosis associated with spondylolisthesis: unilateral approach and use of a microscope and tubular retractor system. Neurosurg Focus 13:1E42002

    • Search Google Scholar
    • Export Citation
  • 7

    Poletti CE: Central lumbar stenosis caused by ligamentum flavum: unilateral laminotomy for bilateral ligamentectomy: preliminary report of two cases. Neurosurgery 37:3433471995

    • Search Google Scholar
    • Export Citation
  • 8

    Spetzger UBertalanffy HReinges MHGilsbach JM: Unilateral laminotomy for bilateral decompression of lumbar spinal stenosis. Part II: Clinical experiences. Acta Neurochir (Wien) 139:3974031997

    • Search Google Scholar
    • Export Citation
  • 9

    Thome CZevgaridis DLeheta OBazner HPockler-Schoniger CWohrle J: Outcome after less-invasive decompression of lumbar spinal stenosis: a randomized comparison of unilateral laminotomy, bilateral laminotomy, and laminectomy. J Neurosurg Spine 3:1291412005

    • Search Google Scholar
    • Export Citation
  • 10

    Weiner BKWalker MBrower RSMcCulloch JA: Microdecompression for lumbar spinal canal stenosis. Spine 24:2268 22721999

  • 11

    Young SVeerapen RO'Laoire SA: Relief of lumbar canal stenosis using multilevel subarticular fenestrations as an alternative to wide laminectomy: preliminary report. Neurosurgery 23:6286331988

    • Search Google Scholar
    • Export Citation


All Time Past Year Past 30 Days
Abstract Views 298 284 42
Full Text Views 151 114 0
PDF Downloads 140 92 0
EPUB Downloads 0 0 0
Google Scholar