Wait Times for Spinal Cord Stimulation Vary by Specialty

Nancy A. Melville

March 18, 2014

PHOENIX, Arizona — Time is of the essence when it comes to the long-term success of spinal cord stimulation therapy for treatment of chronic pain; however, the treating physician's specialty can play a key role in whether the treatment is provided sooner rather than later, according to new research.

Previous data have shown that the procedure's long-term success rate ranges from as high as 75% if provided within 2 years of pain onset to just 15% if delayed 20 years from pain onset.

The new study's lead author, Krishna Kumar, MD, MBBS, a clinical professor of neurosurgery at the University of Saskatchewan, Regina, Canada, said that a trial of spinal cord stimulation should be considered if patients do not respond to conventional medical management within 12 to 16 weeks, but with the procedure commonly viewed as a therapy of last resort, the long-term success rate in the treatment of chronic pain is less than 50%.

In this study, the mean time from onset of the pain syndrome to implantation of a stimulator was more than 5 years and varied significantly by the referring specialty.

"We need to educate physicians that spinal cord stimulation is a viable and effective treatment option for the management of chronic, nonmalignant pain," Dr. Kumar said. "It is necessary to initiate spinal cord stimulation early within the pain care continuum, prior to changes occurring within the brain, to improve success rates."

They reported their findings here at the American Academy of Pain Medicine (AAPM) 30th Annual Meeting.

Dr. Krishna Kumar

Initial Contact

To better identify the factors involved in implantation delays, Dr. Kumar and his colleagues conducted a retrospective review of 532 patients who received the treatment, including 248 men and 189 women (mean age, 59.9 years). They looked at points of delay from initial diagnosis of chronic pain to referral for the procedure.

The researchers found that while initial contact with a physician occurred at a mean of 3.4 months following the development of a pain syndrome, the mean time from symptom onset until implantation was 5.12 years.

Among specialists, neurosurgeons were the fastest to refer patients, with referrals to spinal cord stimulation made an average of 2.69 years after treatment, while orthopedic surgeons and anesthesiologists (nonimplanting physicians) had patients with the longest durations of treatment before referral, at 4.30 and 4.84 years, respectively.

Family physicians treated patients for an average duration of 3.13 years before referral.

"Referral to a spinal cord stimulation implanter took a mean of 2.15 years longer if the patient was referred by a nonimplanting anesthetist vs a neurosurgeon," Dr. Kumar said.

He noted that his previous research has shown awareness of spinal cord stimulation to be low among people who could benefit from the procedure.

"We previously found that 61% of respondents who could benefit from spinal cord stimulation were unaware of it and 87% of patients tried at least 4 different treatments before the use of spinal cord stimulation."

He speculated on several reasons why patients of nonimplanting anesthesiologists and orthopedic surgeons have the longest delays before being referred to spinal cord stimulation.

"Some possible explanations are a lack of recognition of the efficacy of neuromodulation, and among anesthesiologists, there is a tendency to stick with well-rehearsed procedures, such as different types of blocks and trials of various pharmacological agents, as they are well versed in various drug interactions."

Likewise, orthopedic surgeons "invariably proceed with various types of fusion where outcomes may not be clear until 1 year postprocedure."

Aside from the referring specialty, other predictors found to be associated with delay in spinal cord stimulation were age, male sex, and worker's compensation coverage (all P < .0001).

Dr. Kumar asserted that important changes needed to prevent delays include improved pain management training, improved fee schedules for pain therapies, and early access to relevant imaging modalities.

"Worst Offender" Specialties

As a professor of 2 of Dr. Kumar's "worst offender" specialties, anesthesiology and orthopedic surgery, Andre P. Boezaart, MD, said he's not surprised by the findings.

"I instinctively agree with this," said Dr. Boezaart, from the Division of Acute and Perioperative Pain Medicine at the University of Florida College of Medicine in Gainesville.

"Nonimplanting anesthesiologists simply don't deal with these patients, and even if they do deal with acute and perioperative pain issues, their involvement is in the acute settings only," he told Medscape Medical News.

"And if orthopedic surgeons can't operate the pain away they simply cannot and will not treat these patients, and they typically do not want to deal with chronic pain issues," he added.

"They will refer a patient to a pain doctor or neurosurgeon who will then do the referral to spinal cord stimulation."

That tendency may in fact partially explain why neurosurgeons fared relatively well in faster referrals, Dr. Boezaart suggested.

"What is not clear is how many of the neurosurgery patients come from orthopedic surgeons originally, and does that play a role in how neurosurgeons are the 'good guys' here."

Either way, Dr. Boezaart agreed that when it comes to chronic pain, the sooner spinal cord stimulation is offered, the better.

"If you ascribe to the theory of spinal cord wind-up, then it makes a lot of sense to place the spinal cord stimulator as early as possible — before the spinal cord 'winds up' too much — beyond any repair. Personally I refer patients as soon as I can."

The study received no funding. Dr. Kumar is a consultant for Medtronic Inc and Boston Scientific, and he has received research grants from both companies in the past. Dr. Boezaart has disclosed no relevant financial relationships.

American Academy of Pain Medicine (AAPM) 30th Annual Meeting. Abstract 113. Presented March 6, 2014.

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