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Spinal Alignment and Balance

Aug 23, 2025

Overview

The lecture distinguishes alignment from balance in spinal assessment, highlighting the need for both static and dynamic evaluations for optimal function and prevention of complications.

Alignment vs. Balance

  • Alignment refers to the static position of the spine, while balance is dynamic and involves stability during movement.
  • Radiographs (X-rays) show alignment, but advanced imaging like EOS provides horizontal and 3D perspectives for better assessment.
  • Good static alignment on imaging does not guarantee optimal dynamic (functional) balance.

Evaluation Techniques

  • EOS imaging enables assessment of the spine in different planes.
  • Dynamic evaluations include force plate measurements and motion analysis for function and mobility.
  • Local and global balance are interconnected and must both be considered.

Spine and Pelvis Compensation

  • The pelvis plays a critical role in compensating for spinal imbalances.
  • Human posture and balance rely on coordinated muscle, joint, and neurological factors.
  • The "cone of economy" concept describes efficient upright posture with minimal energy use.

Neurology and Compensation

  • Balance involves proprioception (body position sense), vision, and vestibular (inner ear) function.
  • The brain integrates sensory inputs for posture and gaze stabilization.
  • Humans naturally compensate for imbalance through orthopedic and neurological mechanisms.

Aging, Morphotypes & Adaptation

  • Aging affects spinal alignment and pelvic motion, with decreased hip extension leading to compensatory changes.
  • Incidence angle and spinal morphotype (shape) are genetically influenced and may change post-surgery.
  • Ignoring mass distribution (head, torso, pelvis) leads to surgical planning failures.

Surgical Planning & Prevention

  • Preoperative planning should consider compensation above/below fusion zones and mass, not just angles.
  • Postoperative assessment needs dynamic evaluation, not only X-rays.
  • Preventative strategies include preserving junctional (transition) vertebrae and maintaining hip extension reserve.

Practical Assessment & Rehabilitation

  • Simple functional tests: walking speed, stair climbing, squatting, and performing tasks with a cognitive load (dual tasking).
  • Dynamic measurements are important for older adults to time interventions before significant decline.
  • Daily physical exercise, good nutrition, vision correction, proper footwear, and cognitive training help maintain balance.

Key Terms & Definitions

  • Alignment — The static positioning of the spinal column.
  • Balance — The dynamic ability to maintain stability during movement.
  • EOS Imaging System — Advanced imaging technology for 3D spine visualization.
  • Cone of Economy — Concept describing efficient, minimal energy upright posture.
  • Incidence Angle — Measurement relating to pelvic orientation and spine morphotype.
  • Compensation — Body's adaptation to maintain balance in response to changes or deficits.

Action Items / Next Steps

  • Perform dynamic and functional assessments in addition to standard imaging for all patients.
  • Encourage daily balance and strength exercises, especially in older adults.
  • Use simple clinic tests: timed walking, stair climbing, squatting, and dual-task activities.
  • Ensure proper surgical planning that includes evaluation of compensation and mass.
  • Check and preserve hip extension reserve and junctional vertebrae in spinal procedures.