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Chapter Summary
• Context: Aging is heterogeneous, and chronological age alone does not reflect physiological reserve in elderly candidates for spine surgery. Frailty describes a multidimensional syndrome of increased vulnerability to stressors resulting from diminished homeostatic reserve, whereas sarcopenia involves loss of muscle strength, mass, or quality and impaired physical performance. The two conditions overlap but are distinct. Coexisting bone mineral loss creates osteosarcopenia, multiplying biomechanical and clinical risks. In spine surgery, observational studies connect frailty and sarcopenia with increased complications, extended hospitalization, transfusions, thromboembolism, mechanical construct failures, reoperations, and mortality. The challenge lies in screening and recognizing these vulnerabilities preoperatively using objective, structured tools rather than subjective clinical impressions.
• Chapter Objective: To differentiate aging, frailty, and sarcopenia; present validated clinical screening instruments (Fried phenotype, FRAIL scale, EWGSOP2 criteria); and explain their prognostic significance in spine surgery. The chapter incorporates functional, muscular, and bone quality metrics into perioperative optimization and multidisciplinary care.
• Frailty is Not Chronological AgePatients of identical chronological age exhibit widely divergent physiological reserves. Validated screening tools—such as the Fried frailty phenotype (weight loss, exhaustion, low physical activity, slowness, weakness), the FRAIL scale, and the modified Frailty Index (mFI)—structure preoperative risk stratification.
• Sarcopenia: Strength, Mass, and FunctionThe European Working Group on Sarcopenia in Older People (EWGSOP2) diagnosis requires: low muscle strength (grip dynamometry or chair stand test) to establish suspect sarcopenia; confirmed by low muscle quantity/quality (DEXA, BIA, or lumbar CT psoas/paraspinal cross-sectional area); and graded severe by poor physical performance (gait speed, Timed Up and Go). Sarcopenic obesity masks muscle wasting under high BMI.
• OsteosarcopeniaCoexistence of sarcopenia and low bone mineral density (osteopenia/osteoporosis) creates an ultra-vulnerable phenotype for falls, fractures, hardware loosening, proximal junctional kyphosis (PJK), and surgical nonunion.
• Surgical Impact and Risk StratificationFrailty and sarcopenia independently predict perioperative complications, ICU admissions, delirium, infection, prolonged length of stay, and 30-day mortality. Surgical evaluation must look beyond static spinal radiographs to include biological reserve, bone density, nutrition, and social support.
• Multidisciplinary OptimizationComprehensive geriatric assessment, prehabilitation (exercise, resistance training), nutritional support (high-protein supplementation, vitamin D optimization), and bone-targeted therapies (anabolic agents like teriparatide) calibrate surgical invasiveness to the patient's true physiological capacity.
• Clinical Application: Preoperatively, screen elderly spine patients with the FRAIL scale or mFI and measure handgrip strength. On lumbar CT, evaluate paraspinal and psoas muscle cross-sectional area and fatty infiltration (Goutallier grade). In frail or osteosarcopenic patients, tailor the surgical plan: consider staged or less invasive decompression rather than massive multi-level fusion, utilize cement-augmented screws or multiple-rod constructs, initiate preoperative nutritional prehabilitation, and involve geriatric co-management to prevent delirium and medical complications.
