Twelve-month results of a clinical pilot study utilizing pedicle-lengthening osteotomy for the treatment of lumbar spinal stenosis

Clinical article

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Lumbar spinal stenosis (LSS) is a common condition that leads to significant disability, particularly in the elderly. Current therapeutic modalities for LSS have certain drawbacks when applied to this patient population. The object of this study was to define the 12-month postoperative outcomes and complications of pedicle-lengthening osteotomies for symptomatic LSS.


A prospective, single-treatment clinical pilot study was conducted. A cohort of 19 patients (mean age 60.9 years) with symptomatic LSS was treated by pedicle-lengthening osteotomy procedures at 1 or 2 levels. All patients had symptoms of neurogenic claudication or radiculopathy secondary to LSS and had not improved after a minimum 6-month course of nonoperative treatment. Eleven patients had a Meyerding Grade I degenerative spondylolisthesis in addition to LSS. Clinical outcomes were measured using the Oswestry Disability Index (ODI), Zurich Claudication Questionnaire (ZCQ), 12-Item Short-Form Health Survey (SF-12), and a visual analog scale (VAS). Procedural variables, neurological outcomes, adverse events, and radiological imaging (plain radiographs and CT scans) were collected at the 1.5-, 3-, 6-, 9-, and 12-month time points.


The pedicle-lengthening osteotomies were performed through percutaneous approaches with minimal blood loss in all cases. There were no operative complications. Four adverse events occurred during the follow-up period. Clinically, significant improvement was observed in the mean values of each of the outcome scales (comparing preoperative and 12-month values): ODI scores improved from 52.3 to 28.1 (p < 0.0001); the ZCQ physical function domain improved from 2.7 to 1.8 (p = 0.0021); the SF-12 physical component scale improved from 27.0 to 37.9 (p = 0.0024); and the VAS score for leg pain while standing improved from 7.2 to 2.7 (p < 0.0001). Imaging studies, reviewed by an independent radiologist, showed no evidence of device subsidence, migration, breakage, or heterotopic ossification. Thin-slice CT documented healing of the osteotomy site in all patients at the 6-month time point and an increase in the mean cross-sectional area of the spinal canal of 115%.


Treatment of patients with symptomatic LSS with a pedicle-lengthening osteotomy procedure provided substantial enlargement of the area of the spinal canal and favorable clinical results for both disease-specific and non–disease-specific outcome measures at the 12-month time point. Future studies are needed to compare this technique to alternative therapies for lumbar stenosis.

Article Information

Address correspondence to: D. Greg Anderson, M.D., Departments of Orthopaedic Surgery and Neurological Surgery, Thomas Jefferson University/Rothman Institute, 925 Chestnut Street, 5th Floor, Philadelphia, Pennsylvania 19107. email:

Please include this information when citing this paper: published online February 1, 2013; DOI: 10.3171/2012.11.SPINE12402.

© AANS, except where prohibited by US copyright law.



  • View in gallery

    En face fluoroscopic views of the pedicle (left) and of the guide-wire held over the patient's back used to mark the center of the pedicle on the skin (right).

  • View in gallery

    En face (A) and lateral (B) fluoroscopic views show the guide pin placed through the central pedicle. Lateral fluoroscopic views demonstrate the guide pin inserted into the vertebral body (C) and the cannulated reamer used to open a passage through the center of the pedicle (D).

  • View in gallery

    The bone saw used to cut the pedicle has a knob (A, arrow) that can be turned to deploy or retract the cutting blade, and the saw blade (B,arrow) extends from the tip of the bone saw. En face (C) and lateral (D) fluoroscopic views show the bone saw in use, cutting the pedicle. The saw blade (C and D, arrow) can be followed fluoroscopically during the cutting procedure.

  • View in gallery

    The pedicle-lengthening implant is shown in the shortened (A) and expanded (B) states. The implant is inserted into the pedicle as a typical bone screw and is expanded in length after it has been properly positioned across the osteotomy site by the action of an inner screw. Anteroposterior (C) and lateral (D) fluoroscopic views show the pedicle-lengthening implants placed bilaterally over guidewires.

  • View in gallery

    Pedicle-lengthening implants in final position on anteroposterior (left) and lateral (right) fluoroscopic views.

  • View in gallery

    Axial CT scan of the pedicle-lengthening osteotomy site at the 6-month time point demonstrating successful healing of the pedicle gap.


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