SRS Research Award Goes to Povidone Iodine Study

The 2016 Scoliosis Research Society Thomas E. Whitecloud Awards went to researchers who found that a widely used wound irrigant is toxic to growing bone cells and who discovered the true incidence rates of proximal junctional kyphosis (PJK), a prevalent post-surgery complication that can lead to revision surgery in patients with adult severe spinal deformity. They were honored at the International Meeting on Advanced Spine Technologies (IMAST) in July.

For years, surgeons performing scoliosis surgery have used irrigants to reduce wound infections. Now, researchers have found that one particular irrigant—povidone iodine—is actually toxic to growing bone cells. Although it is an effective antimicrobial, it can ambush the actual surgical goal by stopping important bone growth. The irrigant of choice should instead be Vancomycin or Gentamicin, doctors say.

“The Effect of Anti-Microbial Irrigations on Osteoblasts and Bone Formation: An in Vitro Comparison of Vancomycin, Gentamicin and Povidone Iodine, ” lays out the results of a comparative study of the use of different wound irrigants and their effects on osteopaths and bone formation in the lab. Ashleigh Marie Philp; Matthew Peter Newton Ede, FRCS T&O; and Simon W. Jones, Ph.D. were awarded the Thomas E. Whitecloud Best Basic Science Award.

In addition, a team of doctors from Johns Hopkins earned the Thomas E. Whitecloud Best Clinical Paper for their report titled “Incidence of Proximal Junctional Kyphosis in Patients with Adult Spinal Deformity Fused to the Pelvis: A ScoliRisk-1 Sub-analysis.” Authors included: Amit Jain, M.D.; Floreana Naef Kebaish, M.D.; Lawrence G. Lenke, M.D.; Yong Qiu, M.D.; Yukihiro Matsuyama, M.D., Ph.D.; Christopher P. Ames, M.D.; Michael G. Fehlings, M.D., Ph.D., FRCSC; Benny T. Dahl, M.D., Ph.D.; Hossein Mehdian, M.D.; Kenneth MC Cheung, M.D.; Frank J. Schwab, M.D.; Ferran Pellisé, M.D.; Leah Yacat Carreon, M.D., MSc; Christopher I. Shaffrey, M.D.; and Khaled M. Kebaish, M.D., FRCSC.

Proximal junctional kyphosis (PJK) is a major complication that can occur in patients who undergo surgical treatment for adult spinal deformity and may require further surgical intervention. Having accurate incidence rates of PJK is very important for patient counseling and surgical planning.

Researchers found that of the 198 patients whose records were studied almost one quarter of those with severe adult spinal deformity develop symptomatic PJK after surgical fusion to the pelvis, and as many as 10% require revision surgery. Radiographic PJK occurs in 21% of patients. There were no significant differences between patients who developed symptomatic PJK vs. those who developed radiographic PJK in terms of comorbidities or preoperative radiographic characteristics.

Nominees for the Whitecloud Best Basic Science and Clinical awards are selected by the IMAST Committee from the submitted 2016 abstracts for the IMAST and the SRS Annual Meeting. This year, there were more than 1, 500 manuscripts submitted to the Scoliosis Research Society for consideration for the Whitecloud Awards, said committee chair Ronald A. Lehman, Jr., M.D.

During the meeting, attendees vote for their favorite presentation via the IMAST application (app) and the popular votes and manuscript scores are taken into consideration.

Anti-Microbial Irrigations: A Comparison

Matthew Newton Ede and his team set out to study the effect of irrigants that are increasingly being used at the end of surgery to reduce wound infections. Common compounds studied included Povidone Iodine (Betadine or Videne), Gentamicin or Vancomycin.

“Clearly these are effective antimicrobials, but what are the effects on the bone?” asked Ede. “Most of the larger spinal procedures are fusion procedures, meaning that we require the bone to knit together. Clearly it is imperative that these irrigants, whilst reducing infection, do not impede the primary goal of the surgery.”

However, Ede and colleagues found that povidone iodine was significantly toxic to proliferating bone cells. “We discovered that Gentamicin and Vancomycin were safe with regard to preserving bone forming function, even when we increased the dose up to ten times what we would expect to see in clinical practice.

“Infection is a significant problem, ” Ede continued. “We have proven that the use of Vancomycin or Gentamicin is safe with regards to bone formation in the laboratory setting. This is important as these antibiotics are being used ‘off-label’ in this sense and so as clinicians we have to be very sure of what we are doing.”

Other papers have shown that Vin particular is very effective at reducing infection. “We hope that as a result of our work we will have encouraged others to use this practice more widely (irrigation with Vancomycin) and that infection rates in scoliosis surgery will fall, ” Ede added.

Ede said the findings could be considered of benefit in other orthopedic, maxillofacial neurosurgical settings, beyond scoliosis surgeries.

A generous grant from the British Scoliosis Research Foundation made the research possible, Ede said.

Incidence of PJK: A ScolioRisk-1 Sub-Analysis

The primary aim of researchers who undertook a study of PJK was to determine the incidence of symptomatic and radiographic PJK in adults with severe spinal deformity after surgical spinal fusion to the pelvis, according to Amit Jain, lead researcher.

Symptomatic PJK is defined as PJK or proximal junctional failure (PJF) that results in revision surgery; whereas, radiographic PJK is defined as asymptomatic and does not result in revision surgery. Reported rates of radiographic PJK range from 17% to 62%, with most studies reporting rates between 20% and 40%, Jain said.

The secondary aims of the research were to compare the following:

• Clinical and radiographic characteristics of patients who develop symptomatic vs. radiographic PJK,
• Rates of PJK in patients with long vs. short fusion constructs,
• Health-related quality-of-life outcomes of patients with radiographic PJK vs. patients without PJK.

“We hypothesized that while symptomatic PJK would be associated with changes in health related quality of life scores, radiographic PJK will not impact health related quality of life scores, ” Jain said.

“We were surprised to find that there were no significant differences between patients who developed symptomatic PJK vs. those who developed radiographic PJK in terms of comorbidities or preoperative radiographic characteristics, ” continued Jain. “Further, incidence of PJK (symptomatic and radiographic) did not differ significantly between patients with long fusion constructs vs. short fusion constructs. As we suspected, patients with radiographic PJK did not have worse health related quality of scores than patients without PJK.”

The study was a sub-analysis of the Scoli-Risk-1 study, a collaborative international effort from 15 institutions around the globe to evaluate neurologic complications associated with surgical correction of “high risk” complex adult spinal deformity prospective observational cohort.

“This prospective, observational, multicenter study marks the first clinical trial collaboration between AOSpine and the Scoliosis Research Society (SRS), ” Jain said of the team’s research. The study was executed by AO Clinical Investigation and Documentation (AOCID) on behalf of AOSpine and the SRS. “The prospective study was a major undertaking that would not have been possible without cooperation of the Scoli-Risk investigators and AOSpine support staff.”