Blood Loss Minimization and Blood Salvage Techniques for Complex Spinal Surgery

Patients with spinal malalignment may present with disabling back pain, increased fatigue, difficulty maintaining an erect posture, and reduced health-related quality of life (HRQL). The etiopathogenesis of curve progression with ensuing spinal malalignment may be related to various factors such as age-related degeneration, osteomyelitis, trauma, or iatrogenic changes from prior surgery. Less flexible, rigid curves (i.e., fixed deformities) can result after previous fusion and these can be difficult to treat. For these revision cases (e.g., iatrogenic flatback deformity), a surgeon may consider performing lumbar pedicle subtraction osteotomy (PSO) to achieve the desired correction. A lumbar PSO is a three-column osteotomy (Schwab grade 3) that allows approximately 30 degrees of focal correction. More correction can be achieved with an extended PSO (Schwab grade 4). This powerful technique may improve lumbar lordosis, restore global alignment, and improve patient-reported HRQL. However, a PSO is technically challenging and requires complete removal of the posterior elements, bilateral pedicles, and a wedge-shaped portion of the vertebral body with a subsequent osteotomy closure in a controlled fashion. Accordingly, a lumbar PSO is associated with high complication rates, which include neurological deficits, high blood loss, and rod fracture/pseudarthrosis. Appropriate patient selection and some surgical strategies such as satellite or accessory rod placement may reduce complications and instrumentation failure. In this chapter, we review lumbar PSO and focus on patient selection, indications, operative planning, surgical techniques, revision strategies, outcomes, complications, and potential strategies to reduce complications.

The aim of this study was to generate a score based on preoperative characteristics and predictive of the individual probability of allogeneic erythrocyte transfusion in patients undergoing elective thoracolumbar spine surgery.

Two hundred thirty consecutive patients were retrospectively included over a 15-month period (derivation set). Preoperative independent predictors of erythrocyte transfusion from the day of surgery until postoperative day 5 were determined by multivariable analysis, from which a model of individual probability of transfusion was derived and prospectively validated in 125 additional patients (validation set).

Four preoperative independent predictors were associated with transfusion: age older than 50 yr (adjusted odds ratio = 4.9 [2–13.5]), preoperative hemoglobin level less than 12 g/dl (adjusted odds ratio = 6.9 [3.1–17.2]), fusion of more than two levels (adjusted odds ratio = 6.7 [3.1–15.2]), and transpedicular osteotomy (adjusted odds ratio = 19.9 [5.6–98.2]). A 0–4 score (0 = no risk, 4 = maximum risk) predictive of allogeneic transfusion was derived by weighting estimate parameters for each variable in a multivariable logistic regression model. Discriminating capacity of the score was 0.86 [0.81–0.92] in the receiver operating characteristics in the derivation sample and 0.83 [0.75–0.91] in the validation sample. The observed transfusion rates in the validation set and the individual probabilities of erythrocyte transfusion from the score were well correlated (y = 0.98x + 0.04; P < 0.0001), and the observed differences were not statistically different (goodness-of-fit chi-square, P = 0.125). The score was also correlated with the number of erythrocyte units transfused (Spearman ρ = 0.61; P < 0.0001).

The Predictive Model of Transfusion in Spine Surgery may be useful in clinical practice to identify patients undergoing spine surgery at risk of massive bleeding and encourage erythrocyte-saving strategies in these patients.