Quantitative Data-driven Utilization of Hematologic Labs Following Lumbar Fusion

Increased Severity of Anemia Is Associated with Postoperative Complications following a Adult Spinal Deformity Surgery

BACKGROUND

Anemia is a modifiable risk factor for postoperative complications following surgery. This study aimed to determine the impact of preoperative anemia severity on 30-day postoperative complications following adult spinal deformity (ASD) surgery.

METHODS

Adults undergoing spinal fusion for ASD from 2012 to 2018 were identified in the National Surgical Quality Improvement Program database. Patients were substratified into 3 cohorts-non-anemia, mild anemia, and moderate-to-severe anemia-based on World Health Organization definitions. We assessed 30-day wound, cardiac, pulmonary, renal, and thromboembolic complications, as well as sepsis, mortality, postoperative transfusions, extended length of stay, and reoperation. Bivariate analyses and multivariable logistic regression were performed.

RESULTS

Of 2173 patients, 1694 (78%) had no anemia, 307 (14%) had mild anemia, and 172 (8%) had moderate or severe anemia. Following adjustments, patients with mild anemia were more likely to have postoperative blood transfusions (odds ratio [OR] 1.80, P < 0.001) and extended length of stay (OR 1.43, P < 0.001). Patients with moderate-to-severe anemia were at increased risk of organ space infection (OR 3.27, P = 0.028), death (OR 13.15, P = 0.001), postoperative blood transfusion (OR 2.81, P < 0.001), and extended length of stay (OR 3.02, P < 0.001).

CONCLUSIONS

We found a stepwise and approximately two-fold increase in the odds ratio of postoperative transfusion and length of stay with increasing severity of anemia. Moderate-to-severe anemia was associated with increased odds of death and organ space infection. Patients with moderate-to-severe anemia should be medically optimized before ASD surgery.

Spine Surgery and Preoperative Hemoglobin, Hematocrit, and Hemoglobin A1c: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVES

Synthesize previous studies evaluating clinical utility of preoperative Hb/Hct and HbA1c in patients undergoing common spinal procedures: anterior cervical discectomy and fusion (ACDF), posterior cervical fusion (PCF), posterior lumbar fusion (PLF), and lumbar decompression (LD).

METHODS

We queried PubMed, Embase, Cochrane Library, and Web of Science for literature on preoperative Hb/Hct and HbA1c and post-operative outcomes in adult patients undergoing ACDF, PCF, PLF, or LD surgeries.

RESULTS

Total of 4,307 publications were assessed. Twenty-one articles met inclusion criteria.

PCF AND ACDF

Decreased preoperative Hb/Hct were significant predictors of increased postoperative morbidity, including return to operating room, pulmonary complications, transfusions, and increased length of stay (LOS). For increased HbA1c, there was significant increase in risk of postoperative infection and cost of hospital stay.

PLF

Decreased Hb/Hct was reported to be associated with increased risk of postoperative cardiac events, blood transfusion, and increased LOS. Elevated HbA1c was associated with increased risk of infection as well as higher visual analogue scores (VAS) and Oswestry disability index (ODI) scores.

LD

LOS and total episode of care cost were increased in patients with preoperative HbA1c elevation.

CONCLUSION

In adult patients undergoing spine surgery, preoperative Hb/Hct are clinically useful predictors for postoperative complications, transfusion rates, and LOS, and HbA1c is predictive for postoperative infection and functional outcomes. Using Hct values <35-38% and HbA1c >6.5%-6.9% for identifying patients at higher risk of postoperative complications is most supported by the literature. We recommend obtaining these labs as part of routine pre-operative risk stratification.

LEVEL OF EVIDENCE

III.

Knee or Spine Surgery First? A Survey of Treatment Order for Patients With Concurrent Degenerative Knee and Lumbar Spinal Disorders

BACKGROUND

Total knee arthroplasty (TKA) and lumbar spine surgery have been reported to affect the outcomes of each other. There is insufficient evidence to guide the choice of treatment order for patients with both disorders that are equally symptomatic.

METHODS

Five clinical scenarios of concurrent, advanced, degenerative knee and lumbar spinal disorders were designed to survey surgeons' choices of treatment order and rationale. The spinal disorder was consistently degenerative lumbar spinal stenosis, but the knee conditions varied to include (1) osteoarthritis (OA) with varus deformity, (2) OA with valgus deformity, (3) rheumatoid arthritis with a severe flexion contracture, (4) OA without deformity, and (5) bilateral OA with windswept deformities. The survey was distributed to selected clinical members of the Knee Society and Scoliosis Research Society in North America. The surgeons' choices were compared among the 5 scenarios, and their comments were analyzed using text-mining.

RESULTS

Responses were received from 42 of 74 (57%) knee arthroplasty surgeons and 55 of 100 (55%) spine surgeons. The percentages of knee arthroplasty surgeons recommending "TKA first" differed significantly among scenarios: 29%, 79%, 55%, 7%, and 81% for scenarios 1 through 5, respectively (P < .001). A similar pattern was noted for the spine surgeons.

CONCLUSION

For patients with concurrent degenerative knee and lumbar spinal disorders, the severity and type of knee deformity influenced the preference of treatment order in both specialties. Severe valgus deformity and windswept deformities of the knee would drive the decision toward "TKA first."

The Utility of Routinely Obtaining Postoperative Laboratory Studies Following a Minimally Invasive Transforaminal Lumbar Interbody Fusion

STUDY DESIGN

This is a retrospective analysis.

OBJECTIVE

To test the hypothesis that there is limited utility in routinely obtaining postoperative laboratory values following minimally invasive transforaminal lumbar interbody fusion (MIS TLIF).

BACKGROUND DATA

At many institutions, it is routine to obtain a complete blood count and basic metabolic profile (BMP) following a MIS TLIF. However, the utility of this practice has not been well characterized.

METHODS

A total of 332 consecutive patients who underwent a primary, 1-level MIS TLIF for degenerative spinal pathology between 2007 and 2013 were identified. Patients were stratified into low-risk and high-risk cohorts based upon risk for postoperative laboratory abnormalities. Inclusion criteria for the high-risk cohort were malignancy, complicated diabetes, renal failure, liver disease, hematologic disease, or significant intraoperative blood loss (>300 mL). Preoperative and postoperative hemoglobin (Hb), hematocrit, and BMP values were compared. Any interventions that were potentially related to laboratory values were identified.

RESULTS

Totals of 270 low-risk and 62 high-risk patients were identified. Mean postoperative Hb, hematocrit, blood urea nitrogen, sodium, potassium, and calcium values were decreased compared with preoperative values (P<0.001 for each) in both cohorts. Similar changes from preoperative levels were demonstrated in each cohort. No patients received blood product transfusion. Eleven low-risk (4.1%) and 5 high-risk patients (8.1%) received oral potassium supplementation. All patients who received potassium supplementation were asymptomatic. Most patients who were given potassium replacement consumed medications known to decrease serum potassium levels. No other interventions were performed in either group.

CONCLUSIONS

Despite a significant decrease in mean Hb concentration following surgery, no patients required a transfusion. In total, 16 patients received potassium supplementation likely related to medication-related potassium deficits. Overall, these findings suggest that the utility of routinely obtaining a complete blood count or BMP following uncomplicated MIS TLIF may be limited except in the setting of select preoperative comorbidities and/or perioperative risk factors or events.

LEVEL OF EVIDENCE

Level III.