Medical Fitness Evaluation

Age

There is no age that is an absolute contraindication to surgery. Many studies have indicated that age increases mortality and complication rates. Advancing age is often accompanied by an accumulation of comorbidities and decreased postoperative resilience, which can drastically affect surgical outcomes. Life expectancy is considered when planning for a surgical procedure that requires extensive healing time. This is appropriate but it is important to remember that life expectancy depends most heavily on comorbidities rather than age. The chronological age on a chart should not be use as a main decision-making tool when evaluating a patient for surgery.

Frailty

Lack of postoperative resilience, or the physiological reserve to heal from surgery, is termed frailty. Frailty scores do not worsen at the same rate between patients and are not linked to chronological age. Frail patients have increased postoperative mortality across all surgical fields, with odds ratios (ORs) ranging from 1.1 to 4.97, and are at higher risk for falls, skilled nursing home placement, and readmissions. Although there is no universally accepted rating scale for frailty, several key components are measured.

• 1.

  Weakness, also referred to as sarcopenia, is defined as progressive loss of skeletal muscle mass. Often this is assessed by grip strength with cutoff values based on body mass index (BMI) and sex (men: BMI above 28, cutoff of ≤32 kg; women: BMI above 29, ≤21 kg). Calculations of the psoas muscle area in the abdominal region based on magnetic resonance imaging (MRI) have been proposed to be helpful in determining sarcopenia but standard cutoff values have not been established. The use of MRI as an objective measure of sarcopenia will likely be particularly useful in spine surgery as lumbar MRI is often available.

• 2.

  Functional status is the ability to independently complete activities of daily living (ADL). This can be assessed through patient and caregiver questioning about ADL and falls. In spine patients, the ability to ambulate independently and the absences of any falls in the 6 months before surgery have been linked to decreased length of stay and decreased readmission rates.

• 3.

  Nutritional assessment should be conducted before surgery. Malnutrition impairs wound healing and increases the propensity for infections. Mini nutritional assessment, which evaluates BMI and unintentional weight loss, can be completed but this takes 10 to 15 minutes. An alternative to this is a laboratory test for albumin. Nutritionally deficient patients, as defined by a serum albumin of less than 36 g/L, showed 27.6% higher risk of postoperative pulmonary complications compared with patients with normal serum albumin levels.

• 4.

  Dementia screening. This can be efficiently done through Mini-Cog 3 screening which assesses short-term recall and spatial recognition. Preoperative dementia is associated with increased postoperative cognitive dysfunction and postoperative delirium.

Although increased frailty is predictive of overall complications, it most strongly corresponds to increased rates of discharge to skilled nursing facilities. Increased frailty has also been linked to increased length of hospital stay and increased readmission rates.

If patients are found to have a high frailty index, several interventions are recommended ( Table 3.1 ). Patients should be evaluated for polypharmacy to ensure that medication use is optimized. Patients with nutritional deficiency may be supplemented with protein-rich enrichment formulas. If functional limitations are severe, “pre-habbing” therapy for ambulation and strengthening should be considered before surgery when possible. Such therapies can also work on strengthening the muscles involved in inspiration to decrease pulmonary risk. Modifications in surgical planning for frail patients should include consideration of regional anesthesia, shorter operating room time, and less invasive procedures.