MEANS: The Multi-Ethnic Alignment Normative Study and Why It Matters for Spine Surgery

How straight is “straight enough”? Surgeons planning scoliosis, kyphosis and revision surgery need a target, and that target should come from knowing what healthy alignment actually looks like. The Multi-Ethnic Alignment Normative Study (MEANS), led by Dr. Zeeshan Sardar with collaborators in France, Japan, Singapore, Tunisia and the United States, measured standing full-body alignment in 468 healthy adult volunteers aged 18 to 80. Its published papers describe it as the largest multi-ethnic cohort of asymptomatic adult volunteers studied for skeletal alignment.

Why Normal Alignment Matters

Too little lordosis or too much forward lean can leave a patient imbalanced, tired and in pain, which is the problem in flatback deformity. Aiming for a number that does not fit the patient can cause trouble in either direction. Good targets depend on knowing what is normal for a given age, sex and pelvic shape.

What the MEANS Studies Have Shown

  • Healthy alignment changes slowly with age. Thoracic kyphosis increases with age, while lumbar lordosis does not significantly decline. Healthy volunteers compensate with slight pelvic retroversion, knee flexion and neck extension to keep the head centered over the knees.
  • The pelvis sets the target, but not alone. Lumbar lordosis tracks with pelvic incidence and with thoracic kyphosis, while thoracic kyphosis does not track with pelvic incidence. In the MEANS cohort, lordosis could be estimated from pelvic incidence, thoracic kyphosis and age.
  • Segmental shape matters. The lordosis of the lower lumbar spine and the position of the lumbar apex vary with pelvic incidence, so distribution of lordosis between levels matters, not just the total.
  • Race and ethnicity influence alignment. Despite similar pelvic anatomy, Asian volunteers had lower thoracic kyphosis and lumbar lordosis than Caucasian and Arabo-Berber volunteers. Pelvic incidence itself is affected by age, sex, ethnicity and pelvic thickness.
  • Healthy spines come in a spectrum. About one in five healthy volunteers was moderately disproportioned on the GAP score and 3.6% severely so, and about a third had a Roussouly shape that differed from the one predicted by pelvic anatomy. Radiographic malalignment does not always mean symptoms.
  • The neck and the transitions are now mapped. MEANS defined normal cervical alignment and the relationship between neck angle and the T1 slope, the cervicothoracic and thoracolumbar inflection points, the cervical inclination angle, the posterior cranial vertical line and coronal alignment (odontoid-CSVL).
  • A cervical classification system. The most recent MEANS analysis proposes a cervical sagittal classification that helps identify whether a cervical deformity is driven by the neck, the thoracolumbar spine, or both, to guide where surgery should focus.

Together, the MEANS papers give surgeons a reference for what healthy alignment looks like across ages, sexes and populations. Dr. Sardar’s leadership of this work informs the individualized correction targets he uses in deformity and revision planning.

How This Shapes Your Surgical Plan

For deformity, fusion and revision cases, MEANS-derived targets help set a correction goal that reflects the patient’s age, sex and pelvic incidence, rather than one number for everyone. They are one input among several: symptoms, function, bone quality, health and the patient’s own goals all matter, and not every curve needs to be perfected on an X-ray. Where appropriate, the target is built into robotic CT planning, custom rods and patient-specific implants, and then confirmed with intraoperative CT. See Ultra-Personalized Spine Surgery, Patient-Specific Spine Surgery Planning and Custom Rods and Patient-Specific Implants.

Who Benefits Most

Frequently Asked Questions

Does MEANS mean everyone gets the same target?

No. The point is the opposite: targets vary with age, sex and pelvic anatomy, and are weighed against each patient’s symptoms and goals.

Is a “perfect” X-ray always the goal?

No. Healthy people show a range of alignment, and the aim of surgery is better function and less pain, not matching a number.

MEANS Publications

  1. Sardar ZM, et al. Proposal of a cervical sagittal classification system to guide surgical treatment for adult cervical deformity: a MEANS cohort analysis. Spine (Phila Pa 1976). 2026;51(11):773-782. PubMed
  2. Reyes JL, Miller R, et al., Sardar ZM. The variability of the cervicothoracic inflection point: a cohort analysis of the MEANS. Global Spine J. 2025;15(4):2409-2414. PubMed
  3. Shen Y, Sardar ZM, Malka M, et al. Characteristics of spinal morphology according to the “current” and “theoretical” Roussouly classification systems in a diverse, asymptomatic cohort: MEANS. Global Spine J. 2025;15(2):1295-1305. PubMed
  4. Malka M, Sardar ZM, et al. The thoracolumbar inflection point in a population of asymptomatic volunteers: a MEANS cohort study. Global Spine J. 2025;15(2):438-444. PubMed
  5. Shen Y, Sardar ZM, Malka M, et al. Characteristics of spinal morphology according to the Global Alignment and Proportion (GAP) score in a diverse, asymptomatic cohort: MEANS. Spine (Phila Pa 1976). 2024;49(14):979-989. PubMed
  6. Park PJ, Hassan FM, et al., Sardar ZM, et al. The posterior cranial vertical line: a novel radiographic marker for classifying global sagittal alignment. Neurospine. 2023;20(3):790-797. PubMed
  7. Sardar ZM, Kelly M, Le Huec JC, et al. Sagittal spinal alignment varies with an individual’s race: results of the MEANS. Spine Deform. 2023;11(6):1355-1362. PubMed
  8. Shen Y, Sardar ZM, et al. Variation in lumbar shape and lordosis in a large asymptomatic population: a MEANS study. Spine (Phila Pa 1976). 2023;48(11):758-765. PubMed
  9. Le Huec JC, Sardar ZM, et al. Cervical inclination angle: normative values in an adult multiethnic asymptomatic population. Neurospine. 2022;19(4):883-888. PubMed
  10. Sardar ZM, Cerpa M, Kelly M, et al. Age and gender based spinopelvic and regional spinal alignment in asymptomatic adult volunteers: results of the MEANS. Spine (Phila Pa 1976). 2022;47(19):1382-1390. PubMed
  11. Sardar ZM, Cerpa M, Hassan F, et al. Age- and gender-based global sagittal spinal alignment in asymptomatic adult volunteers: results of the MEANS. Spine (Phila Pa 1976). 2022;47(19):1372-1381. PubMed
  12. Hasegawa K, Hatsushikano S, Le Huec JC, Sardar Z, et al. Pelvic thickness, sex, ethnicity, and age affect pelvic incidence in healthy volunteers of the MEANS database. Eur Spine J. 2022;31(6):1421-1430. PubMed
  13. Zuckerman SL, Sardar ZM, et al. The odontoid-CSVL distance in a global population of asymptomatic volunteers: normative values and implications for spinal coronal alignment. Eur Spine J. 2021;30(12):3639-3646. PubMed
  14. Hasegawa K, Sardar ZM, Lenke LG, et al. Normality of sagittal spinal alignment parameters reveals evolutionary signals in healthy adults across five countries. Sci Rep. 2025;15:35484. Article

More research is on the publications page. Browse the Patient Education Library or return to the home page.

About Dr. Zeeshan Sardar
Dr. Sardar, MD, MSc, F.R.C.S.C, is Co-Chief of Spinal Deformity at Och Spine Hospital at NewYork-Presbyterian / Columbia University. To schedule, call 212-932-5187 or visit the contact page.

This page is for educational purposes only and does not constitute individualized medical advice. Please consult a qualified spine specialist to discuss your specific condition.