Share this page
Adult Spinal Deformity Surgery
Smith-Petersen Osteotomy (SPO)
An in-depth, evidence-based explanation of the Smith-Petersen osteotomy — a posterior bone cut used to restore forward balance, classically in stiff, forward-stooped spines.
The Smith-Petersen osteotomy, or SPO, is one of the original spinal osteotomies, and remains a valuable tool for correcting a spine that is stooped forward. It is a posterior-column osteotomy: a V-shaped wedge of bone is removed from the back of the spine at a segment, and closing this wedge hinges the spine backwards, opening at the front through the disc to restore a more upright posture. Each SPO delivers a modest correction, so several are often performed to produce a smooth overall change. It is classically used in stiff, forward-stooped spines, and this page explains what the procedure involves and what the evidence shows.
For information only — not medical advice. The content on this page is patient education to help you understand a condition or treatment. It is not a substitute for personalised assessment by a qualified clinician. Always consult your doctor or specialist about your own symptoms, diagnosis, and treatment decisions.
When an SPO is used
An SPO is used to restore forward balance where the spine is stooped and reasonably mobile at the front, so that opening the disc space contributes to the correction. It is a classic treatment for the fixed forward stoop of conditions such as ankylosing spondylitis, and for flatback where the natural lumbar curve has been lost. Because each osteotomy gives a moderate correction, several are usually combined; where a single large correction is needed through a rigid, fused segment, a three-column osteotomy such as a pedicle subtraction osteotomy may be preferred instead.
What the operation involves
The osteotomy is performed from the back. A wedge of bone including the facet joints is removed at the chosen level or levels, and the posterior spine is then compressed to close the wedge, hinging the spine into a more upright position and opening the front of the disc. Pedicle screws and rods apply and hold the correction, and bone graft is added so the segments fuse. Because the correction relies partly on the front of the spine opening, and because the cord and nerves are nearby, the technique is carried out carefully with neuromonitoring.
What the evidence shows
The evidence positions the SPO within the family of osteotomies and clarifies when it is preferable. Comparative studies of Smith-Petersen versus pedicle subtraction osteotomy show that the SPO gives a gentler, distributed correction suited to more mobile spines, while the PSO delivers a larger single-level correction for rigid deformity, and decision-making analyses help choose between osteotomy types. More recent work continues to refine technique and its role in sagittal correction. The balanced view is that the SPO is a well-established, effective osteotomy for restoring forward balance in suitable, more mobile deformities.
What to expect
The procedure is carried out under general anaesthetic as part of a deformity correction, usually with a hospital stay of several days and a recovery measured in months, supported by rehabilitation. The correction is achieved during surgery and held by the metalwork while the treated levels fuse. As with any deformity surgery there are risks, which are discussed fully beforehand, and whether an SPO — as opposed to a more powerful osteotomy — is the right choice is decided together.
The information provided on this page is intended for educational purposes only and should not be considered personalised medical advice. Every patient is different, and treatment options, risks, expected recovery and outcomes depend upon an individual's diagnosis, general health and personal circumstances. Decisions regarding treatment should always be made following consultation with your treating spinal surgeon or healthcare professional.
Evidence & further reading
- —Cho KJ, Bridwell KH, et al. Comparison of Smith-Petersen versus pedicle subtraction osteotomy for the correction of fixed sagittal imbalance. Spine 2005. (PMID 16166890)
- —Bridwell KH. Decision making regarding Smith-Petersen versus pedicle subtraction osteotomy versus vertebral column resection for spinal deformity. Spine 2006. (PMID 16946635)
- —Jiang J, et al. Combining pedicle subtraction and Smith-Petersen osteotomy in correcting severe ankylosing spondylitis kyphosis. Sci Rep 2025. (PMID 40325136)
- —Polly DW, et al. Does a hinged operating table facilitate sagittal correction in TLIF with Smith-Petersen osteotomy? Clin Orthop Relat Res 2024. (PMID 38038970)
- —Rostami M, et al. Spinal osteotomies for cervicothoracic sagittal imbalance: a systematic review and meta-analysis. Global Spine J 2025. (PMID 40072901)
Found this helpful? Share it
Discuss this with Mr Madi
Personalised, consultant-led advice
Every patient is different. The information on this page is a starting point — Mr Madi will tailor any plan to your specific imaging, symptoms and goals.