Can Standard Work Reduce Complications in Adult Spinal Deformity Surgery?

North American Spine Society 34th Annual Meeting Highlight

Peer Reviewed

Douglas C. Burton, MD, made a call for standardizing the surgical treatment of adult spinal deformity surgery, including use of a patient optimization protocol, at the North American Spine Society 34th Annual Meeting in Chicago, IL.

“The expectations of our aging population are creating an epidemic of patients presenting with symptomatic spinal deformity,” said Dr. Burton, who is the Marc and Elinor Asher Spine Professor and Vice-Chairman of the Department of Orthopedic Surgery at the University of Kansas School of Medicine in Kansas City. “In the value equation of adult spinal deformity surgery, the benefits—particularly the cost-effectiveness—becomes negligible when we start laying in reoperations and readmissions.”

man grips his painful low backExpectations of our aging population are creating an epidemic of patients presenting with symptomatic spinal deformity. There is good evidence to support standardizing preoperative treatment of adult spinal deformity. Photo Source: iStock.com.While researchers have suggested that complications of adult spinal deformity (ASD) surgery can be decreased by only operating on healthier patients, “the problem is that if you start limiting who you are going to operate on, you are eliminating the patients who get the most benefit from surgery,” Dr. Burton said.1 In fact, research suggests that the biggest delta in improvement comes from operating on the sickest and frailest patients, he noted.2

“How do we navigate between these two tensions if we want to lower the risk for complications, but we know that the patients who gain the most benefit from ASD surgery are the ones who seem to be at the highest risk?,” Dr. Burton asked the audience at NASS. “We thought that a lot of the work probably needs to be done before we get to the operating room, and if we standardize our approach to patient optimization and the performance of adult spinal deformity surgery, we can reduce complications.”

Optimizing Adult Spinal Deformity Surgery

Dr. Burton and colleagues performed a systematic review of 12 items (ie, 9 patient factors and 3 operative factors) to investigate the potential association of these factors with complications, reoperations, and readmissions in ASD surgery to develop a standard work protocol for patient optimization.3,4

Body Mass Index
The first factor considered was body mass index (BMI). Approximately 85% of studies on this topic showed an association between BMI and increased complications in patients undergoing ASD surgery. For example, a retrospective review of a multicenter prospective database of adults undergoing spinal deformity surgery found that obese patients had a higher overall incidence of major complications (incidence rate ratio, 1.54; P=0.02) and wound infections (odds ratio, 4.88; P=0.02) complications with increasing BMI.5

As a result, Dr. Burton and colleagues at the University of Kansas School of Medicine do not operate on any patient with a BMI >35. Patients are referred to the institution’s weight management clinic or for bariatric surgery.

“I’ve operated on several patients who have had 50 to 100 lb weight losses before surgery,” Dr. Burton said. “It takes time in the clinic to have this conversation, but it works.”

Bone Density
Several studies have shown an association between low bone density and screw loosening.3,4 For example, a meta-analysis by Liu et al showed that low bone mineral density was linked to a more than two-fold increased risk for proximal junctional kyphosis in patients undergoing ASD (odds ratio, 2.37; P<0.001).6

Thus, Dr. Burton’s team performs a dual-energy X-ray absorptiometry (DEXA) scan on every adult being considered for a 2-level or greater thoracolumbar fusion. A T-score of -1.5 is used as a cutoff for surgery, and patients who do not meet this criterion are treated with abaloparatide 80 mcg administered subcutaneously daily for three months to increase bone mineral density before performing surgery. The researchers are still gathering evidence to determine whether this treatment has a beneficial effect on outcomes.

Smoking
There is fair evidence of an association between smoking and reoperations, however, “It was interesting that the evidence wasn’t as strong as I thought it was going to be for smoking,” Dr. Burton said.3,4

All patients at Dr. Burton’s institute are serum tested and are not scheduled for ASD surgery unless they have a negative serum cotinine level.

Mental Health
While mental health is another important aspect to consider, how to optimize patients with depression or psychiatric disorders is an area that still needs more work, Dr. Burton explained.

“When we looked at the literature, basically nearly every study showed an association between low mental health and some type of increased complications and reoperations,” Dr. Burton said.3,4 “The problem is how do you measure mental health, and what do you do with the data?”

“We’re not screening for mental health right now, and we’re not really sure what we should be screening for,” he said. Patients with uncontrolled depression or other psychiatric disorders are either referred to their psychiatrist for reevaluation and/or are not offered surgery.

Frailty
“There is fair evidence that frailty is associated with increased complications following ASD surgery,” Dr. Burton said.3,4 Several retrospective cohort studies have identified associations between frailty and increased complications following ASD surgery. The 11-item modified Frailty Index is an effective risk stratification tool, Dr. Burton said, adding that a 5-item Frailty Index recently was proposed.7

“The question is: can you optimize frailty?,” Dr. Burton asked. While frailty is probably not easily modifiable, sarcopenia may be able to be improved, he said.

“We are right now just starting to quantify sarcopenia with sit/stand tests and hand dynamometers,” Dr. Burton said. “We think that there is a role for a prehabilitation program to improve sarcopenia prior to surgery. It may be that prehabilitation will improve the ability of the patient to be discharged to home rather than to a skilled nursing or rehabilitation program.”

In terms of nutrition, Dr. Burton’s systematic review showed fair evidence supporting an association between serum markers for malnutrition (ie, albumin and prealbumin) and complication rates and readmissions in patients undergoing spinal fusion surgery.3,4

“Thus, we check pre-albumin and albumin levels on every patient, and if they have albumin levels <3.5, pre-albumin levels <20, or a BMI <20, we refer them to a nutritionist,” Dr. Burton told NASS attendees.

Hemoglobin A1C
While many studies have examined the impact of a having diabetes on ASD complications, Dr. Burton believes that uncontrolled hemoglobin A1C (HbA1C) levels (which are less commonly examined in clinical trials) may have more of an impact on the risk of complications than a diabetes diagnosis. His systematic review found fair evidence for an association between a HbA1C and an increased incidence of adverse events.3,4

At his institution, the cutoff for surgery in a patient with diabetes is a HbA1C ≤8. Patients with high levels are sent back to their primary care physician or endocrinologist for treatment to reduce their HbA1C level.

Hemoglobin
Seven studies in the literature found fair evidence that low preoperative hemoglobin levels (<12 gm/dL for women and <13.5 gm/dL for men) are associated with an increased risk for intraoperative transfusion.3,4 Dr. Burton and colleagues found conflicting evidence regarding the impact of low hemoglobin levels on other complications of ASD surgery.

While Dr. Burton’s team does not treat patients with low hemoglobin levels preoperatively currently, this is an aspect of care that he hopes to include in the standard work protocol to study whether pretreatment helps lower the incidence of transfusion.

Vitamin D
Dr. Burton and colleagues identified one systemic review and two observational studies providing fair evidence that preoperative vitamin D deficiency is associated with pseudarthrosis and pain.3,4

“It is amazing to me how many people have low vitamin D levels,” Dr. Burton said. While his team does not delay surgery due to low vitamin D level, they start patients with 25-OH Vitamin D (calcifediol) levels <30 ng/mL on supplements:

  • Patients with levels of 20 to 30 ng/mL are instructed to take 1000 IU vitamin D3 (cholecalciferol) over previous intake
  • Patients with levels of 10 to 20 ng/mL are instructed to take 2000 IU vitamin D3 over previous intake and are rechecked in 3 to 6 months
  • Patients with levels <10 ng/mL are instructed to take 5000 IU vitamin D3 over previous intake and are rechecked in 3 to 6 months.

Patients are also given calcium citrate 630 to 1260 mg/day depending on dairy intake.

Operative Factors
Good evidence was found that preemptive goal-directed fluid therapy (GDFT) leads to decreased complications and mortality in ASD surgery.3,4 However, there is a lack of agreement on how to standardize fluid management. Dr. Burton’s team works with the anesthesia team to achieve a goal of 3:1 crystalloid to colloid ratio for all ASD surgeries.

In addition, good evidence was found in the literature that tranexamic acid reduces blood loss and transfusion requirements.3,4

“A big debate right now is whether to use high- or low-dose tranexamic acid,” Dr. Burton said. “I use a low-dose 10 mg/kg load, and a 1 mg/kg/hr continuous infusion.”

Use of tranexamic acid lowers the seizure threshold, as has been noted in cardiac surgery patients.8 Dr. Burton said he had 2 patients experience seizures while taking tranexamic acid, and that the use of total IV anesthesia with propofol may protect against seizures.

“The big thing I’ve noticed is I haven’t had a patient develop a coagulopathy in the last 2 years, and I do not use fresh frozen plasma any more even with big blood loss, so that has been really good,” Dr. Burton said.

Furthermore, Dr. Burton discussed whether age-appropriate realignment is associated with decreased complications, readmissions, or reoperations after adult spinal surgery.

“This patient-specific alignment is new, and there is insufficient evidence in the literature right now to address this topic,” Dr. Burton said.

Conclusion

“There is good evidence to support standardizing the preoperative surgical treatment of ASD,” Dr. Burton concluded. “Patient optimization is really important. As medicine moves to a health system-oriented approach, if we’re not leading this movement to standardization, someone else is going to do it for us, and I don’t think any of us want that.”

Disclosures
Dr. Burton disclosed the following relationships: DePuy Synthes Spine (Consultant, Royalties, Research Support), AlloSource (Consultant), Pfizer (Research Support), Progenerative Medical (Consultant, Stock), and Deputy Editor, Spine Deformity.

Updated on: 12/20/19
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Pre-Operative Planning Reduces Complication Risk in Adult Spinal Deformity Surgery
Douglas C. Burton, MD
Marc & Elinor Asher Spine Professor and Vice Chairman
Department of Orthopedic Surgery
University of Kansas School of Medicine
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