title: Impact of pedicle-lengthening osteotomy on spinal canal volume and neural foramen size in three types of lumbar spinal stenosis.
abstract: OBJECTIVE
  Pedicle-lengthening osteotomy is a novel surgery for lumbar spinal stenosis (LSS), which achieves substantial enlargement of the spinal canal by expansion of the bilateral pedicle osteotomy sites. Few studies have evaluated the impact of this new surgery on spinal canal volume (SCV) and neural foramen dimension (NFD) in three different types of LSS patients.
  
  
  METHODS
  CT scans were performed on 36 LSS patients (12 central canal stenosis (CCS), 12 lateral recess stenosis (LRS), and 12 foraminal stenosis (FS)) at L4-L5, and on 12 normal (control) subjects. Mimics 14.01 workstation was used to reconstruct 3D models of the L4-L5 vertebrae and discs. SCV and NFD were measured after 1 mm, 2 mm, 3 mm, 4 mm, or 5 mm pedicle-lengthening osteotomies at L4 and/or L5. One-way analysis of variance was used to examine between-group differences.
  
  
  RESULTS
  In the intact state, SVC and NFD were significantly larger in the control group compared with the LSS groups (P<0.05). After lengthening at L4, the percentage increase in SCV (per millimetre) was LRS>CCS>FS>Control. After lengthening at L5 and L4-L5, the percentage increase in SCV (per millimetre) was LRS>FS>CCS>Control. After lengthening at L4 and L4-L5, the percentage increase in NFD (per millimetre) was FS>CCS>LRS>Control. After lengthening at L5, the percentage increase in NFD (per millimetre) was CCS>LRS>control>FS.
  
  
  CONCLUSIONS
  LRS patients are the most suitable candidates for treatment with pedicle-lengthening osteotomy. Lengthening L4 pedicles produced larger percentage increases in NFD than lengthening L5 pedicles (p < 0.05). Lengthening L4 pedicles may be the most effective option for relieving foraminal compression in LSS patients.Cite this article: P. Li, L. Qian, W. D. Wu, C. F. Wu, J. Ouyang. Impact of pedicle-lengthening osteotomy on spinal canal volume and neural foramen size in three types of lumbar spinal stenosis. Bone Joint Res 2016;5:239-246. DOI: 10.1302/2046-3758.56.2000469.
authors.affiliation: Department of Anatomy, Southern Medical University and Guangdong Provincial Key Laboratory of Medical Biomechanics and Academy of Orthopedics of Guangdong Province, Guangzhou, 510515, P. R. China.
authors.forename: P
authors.initials: P
authors.lastname: Li
authors.affiliation: Department of Anatomy, Southern Medical University and Guangdong Provincial Key Laboratory of Medical Biomechanics and Academy of Orthopedics of Guangdong Province, Guangzhou, 510515, P. R. China.
authors.forename: L
authors.initials: L
authors.lastname: Qian
authors.affiliation: Department of Orthopedic Surgery, Wuzhou Red Cross Hospital, Wuzhou, Guangxi, 543000, P. R. China.
authors.forename: W D
authors.initials: WD
authors.lastname: Wu
authors.affiliation: Department of Orthopedic Surgery, The Affiliated Hospital of Putian University, and the Affiliated Putian Hospital of Southern Medical University, Putian, Fujian, 351100, P.R.China.
authors.forename: C F
authors.initials: CF
authors.lastname: Wu
authors.affiliation: Department of Anatomy, Southern Medical University, Key Laboratory of Medical Biomechanics, Academy of Orthopedics of Guangdong Province, Guangzhou, China jouyang@126.com.
authors.forename: J
authors.initials: J
authors.lastname: Ouyang
keywords: 3D reconstructions; Neural foraminal dimension; Pedicle lengthening; Spinal canal volume; Spinal stenosis