Treating long wait-times dictate long-term success of spinal cord stimulation therapy

Mar 7 2014

Success rates soared to 75% for patients who waited less than 2 years for a spinal cord stimulator (SCS) implant, compared with 15% for patients whose implants happened 20 years after the onset of pain, according to a retrospective analysis. The length of time patients waited for a referral also varied by specialty, as shown in a scientific poster presented today at the 30th Annual Meeting of the American Academy of Pain Medicine.

The study authors placed their findings in context by noting that fewer than 50% of patients currently report long-term success with SCS in the treatment of chronic pain. Improving wait times could significantly improve success rates, said lead author Krishna Kumar, MD, of Regina General Hospital in Regina, Saskatchewan, Canada.

"The success of SCS is time sensitive, in that as wait times decline, long-term outcomes with SCS are enhanced," Dr. Kumar said.

Dr. Kumar cited barriers to referral that included lack of uptake and awareness among healthcare providers, patients and payers; ongoing reimbursement concerns; and fragmentation of pain-care delivery. Moreover, Dr. Kumar cited return to employment as a metric that has been unfairly employed to curtail access to SCS, a tactic he said downplays benefits of SCS for quality of life, pain and depression.

The study included 443 patients who received SCS. Beginning with the initial pain diagnosis, investigators examined points of delay to referral for implantation by primary care physicians and specialists. The effects on pain duration of gender, age, referring specialty, and their interactions were analyzed using a 2-way ANOVA. A multiple linear regression model that incorporated patient demographic characteristics and components of wait times was developed to predict factors responsible for delays in SCS implantation.

Patients first saw a physician an average of 3.4 months after developing a pain syndrome. Family physicians managed patients for 11.9 months. Specialists then took over management for an additional 39.8 months on average.

The mean time to implantation from symptom onset was 5.12 years. Neurosurgeons were quickest to make a referral, whereas, non-implanting anesthetists were most likely to delay implantation. In fact, referral for SCS treatment took 2.15 years longer if a non-implanting anesthetist vs. a neurosurgeon referred the patient.

Successful SCS outcomes depend on appropriate candidate selection, and Dr. Kumar highlighted the importance of examining underlying pain pathology to help determine who might benefit. For example, patients suffering from failed back surgery syndrome, complex regional pain syndrome, refractory angina pectoris, pain due to peripheral vascular disease, postherpetic neuralgia, chronic migraine or post-surgical neuropathy are considered good candidates for SCS. Red flags Dr. Kumar cited were secondary gain from litigation, persistent uncontrolled or undiagnosed psychiatric disorder, unwillingness to curb inappropriate drug use and cognitive issues that could interfere with operation of SCS equipment.

Education, patient advocacy, basic science and clinical research all could aid the integration of SCS into the pain-management continuum, Dr. Kumar concluded.

"Chronic pain is a disease unto itself, which is responsible for physical and psychosocial suffering. The importance of timely treatment must, therefore, be recognized by all physicians."