How the spine differs in standing and in sitting—important considerations for correction of spinal deformity

Hey, Hwee Weng Dennis; Teo, Alex Quok An; Tan, Khee Giap; Ng, Li Wen Nathaniel; Lau, Leok-Lim; Liu, Ka-Po Gabriel; Wong, Hee-Kit

doi:10.1016/j.spinee.2016.03.056

Cited by 87 publications

(93 citation statements)

References 37 publications

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“…The results indicated that in the sitting position, the curvature of lumbar lordosis decreased by 50% and PT increased by 25%. Other studies yielded similar results, which can be summarized as a straightened curve in the lumbar region, pelvic retroversion, and forward displacement of sagittal balance [2][3][4][5]11 . Hey et al compared the spinal sagittal alignment in three weightbearing positions (standing, erect sitting, and natural sitting) in healthy subjects and found that LL decreased by approximately 80% in the natural sitting position; furthermore, the curvature of the trunk was vaguely C-shaped 3 .…”

Section: Discussionsupporting

confidence: 54%

“…All patients met the following inclusion criteria: patients who received PLIF with the lower instrumented vertebra located in the lumbar or sacral regions, and fusion levels of ≤ 4. The exclusion criteria were as follows: patients (1) who underwent other spinal surgeries, (2) with coronal deformity and adjacent segment instability, (3) with severe lower back pain affecting sitting and standing position or an Oswestry Disability Index of > 40, (4) with hip or knee joint contracture, (5) with vertebral fracture, (6) with neuromuscular disorders, (5) with severe osteoporosis, and (7) with internal xation breakage or pseudarthrosis formation.…”

Section: Patientsmentioning

confidence: 99%

“…Previous studies have investigated the basic changes occurring in the lumbar and pelvic regions when moving from the standing to sitting position in healthy subjects, which can be summarized as a straightened curve in the lumbar region (decreased lumbar lordosis) and pelvic retroversion (increased pelvic tilt) [1][2][3][4][5] . Spinal sagittal alignment is reported to greatly affect the clinical outcomes and quality of life 6,7 .…”

Section: Introductionmentioning

confidence: 99%

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Differences in Standing and Sitting Spinopelvic Sagittal Alignment for Patients with Posterior Lumbar Fusion: Important Considerations for the Changes of Unfused Adjacent Segments Lordosis

Sun

Zhou

Wang

et al. 2020

Preprint

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Objective: This study aimed to describe the changes in spinopelvic sagittal alignment in the sitting position after posterior lumbar fusion, and to identify the factors influencing unfused adjacent segment lordosis.Methods: Consecutive patients with lumbar degenerative disease who underwent posterior lumbar interbody fusion between December 2010 and April 2012 were recruited. Lateral full spine radiographs were obtained in the standing, erect sitting, and natural sitting positions. Spinopelvic parameters were measured preoperatively and at the final follow-up. Results: The data of 63 patients were analyzed in this study. The average age was 61.6±11.0 years. When changing from standing to sitting at the final follow-up, all spinopelvic sagittal parameters with the exceptions of pelvic incidence and thoracic kyphosis were significantly altered. The most noticeable changes occurred in the natural sitting position, with the spine slumped toward achieving a C-shaped sagittal profile. Multiple linear regression analysis revealed that when changing to a natural sitting position, age and fusion levels reflected the changes in lumbar lordosis (ΔLL), age and lumbosacral fusion reflected the changes in upper residual lordosis (ΔURL). Conclusion: The most noticeable changes in spinopelvic sagittal alignment occurred in the natural sitting position after lumbar fusion. Age, fusion levels, and lumbosacral fusion significantly influenced the differences in LL and URL between the standing and natural sitting position. These characteristics should be fully considered when planning spinal realignment surgery and investigating the etiological factors of junctional complications.

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Section: Discussionsupporting

confidence: 54%

Section: Patientsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Differences in Standing and Sitting Spinopelvic Sagittal Alignment for Patients with Posterior Lumbar Fusion: Important Considerations for the Changes of Unfused Adjacent Segments Lordosis

Sun

Zhou

Wang

et al. 2020

Preprint

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“…Lastly, it has recently been found that the lumbar spine changes its alignment in various different postures (22,23) with both the L4/5 and L5/S1 levels of the spine moving into flexion together with pelvic retroversion. By rendering the spine immobile during fusion and creating a lordosis ending at L5, high mechanical stress can happen in the LIV of L5 or the remaining L5/S1 joint during pelvic retroversion when sitting.…”

Section: A B Cmentioning

confidence: 99%

Distal junctional failure secondary to L5 vertebral fracture—a report of two rare cases

Tan

Hey

et al. 2017

J. Spine Surg.

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Distal junctional failure (DJF) with fracture at the last instrumented vertebra is a rare occurrence. In this case report, we present two patients with L5 vertebral fracture post-instrumented fusion of the lumbar spine. The first patient is a 78-year-old female who had multi-level degenerative disc disease, spinal stenosis and degenerative scoliosis involving levels T12 to L5. She underwent instrumented posterolateral fusion (PLF) from T12 to L5, and transforaminal lumbar interbody fusion (TLIF) at L2/3 and L4/5. Six months after her operation, she presented with a fracture of the L5 vertebral body necessitating revision of the L5 pedicle screws, with additional TLIF of L5/S1. The second patient is a 71-year-old female who underwent decompression and TLIF of L3/4 and L4/5 for degenerative spondylolisthesis. Six months after the surgery, she developed a fracture of the L5 vertebral body with loosening of the L5 screws. The patient declined revision surgery despite being symptomatic. DJF remains poorly understood as its rare incidence precludes sufficiently powered studies within a single institution. This report aims to contribute to the currently scarce literature on DJF.

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“…While respecting the advantages of "as anterior as possible" cage placement for lordosis realignment, a mechanically more stable anterior column reconstruction from cage placement may be preferred. This includes situations when the lumbar spine is required to be fused in lordoses of varying magnitudes (over-and undercorrection strategies [20][21][22]) and curve shapes (restoring Roussouly curve type strategies [1]).…”

mentioning

confidence: 99%

Sagittal Radiographic Parameters of the Spine in Three Physiological Postures Characterized Using a Slot Scanner and Their Potential Implications on Spinal Weight-Bearing Properties

Hey¹,

Ng²,

Loh³

et al. 2021

Asian Spine J

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To compare and understand the load-bearing properties of each functional spinal unit (FSU) using three commonly assumed, physiological, spinal postures, namely, the flexed (slump sitting), erect (standing) and extended (backward bending) postures. Overview of Literature: Sagittal spinal alignment is posture-dependent and influences the load-bearing properties of the spine. The routine placement of intervertebral cages "as anterior as possible" to correct deformity may compromise the load-bearing capabilities of the spine, leading to complications. Methods: We recruited young patients with nonspecific low back pain for <3 months, who were otherwise healthy. Each patient had EOS images taken in the flexed, erect and extended positions, in random order, as well as magnetic resonance imaging to assess for disk degeneration. Angular and disk height measurements were performed and compared in all three postures using paired t-tests. Changes in disk height relative to the erect posture were caclulated to determine the alignment-specific load-bearing area of each FSU. Results: Eighty-three patients (415 lumbar intervertebral disks) were studied. Significant alignment changes were found between all three postures at L1/2, and only between erect and flexion at the other FSUs. Disk height measurements showed that the neutral axis of the spine, marked by zones where disk heights did not change, varied between postures and was level specific. The load-bearing areas were also found to be more anterior in flexion and more posterior in extension, with the erect spine resembling the extended spine to a greater extent. Conclusions: Load-bearing areas of the lumbar spine are sagittal alignment-specific and level-specific. This may imply that, depending on the surgical realignment strategy, attention should be paid not just to placing an intervertebral cage "as anterior as possible" for generating lordosis, but also on optimizing load-bearing in the lumbar spine.

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How the spine differs in standing and in sitting—important considerations for correction of spinal deformity

Cited by 87 publications

References 37 publications

Differences in Standing and Sitting Spinopelvic Sagittal Alignment for Patients with Posterior Lumbar Fusion: Important Considerations for the Changes of Unfused Adjacent Segments Lordosis

Differences in Standing and Sitting Spinopelvic Sagittal Alignment for Patients with Posterior Lumbar Fusion: Important Considerations for the Changes of Unfused Adjacent Segments Lordosis

Distal junctional failure secondary to L5 vertebral fracture—a report of two rare cases

Sagittal Radiographic Parameters of the Spine in Three Physiological Postures Characterized Using a Slot Scanner and Their Potential Implications on Spinal Weight-Bearing Properties

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