May 29, 2007

Spinal Interventions — Interventional Radiology Experiences in Treating Back Pain
By Beth W. Orenstein
For The Record
Vol. 19 No. 11 P. 32

Physicians have used epidural steroid injections (ESIs) to treat back pain since the early 1950s. Today, epidural injections are used in the thoracic, cervical, and lumbar spines, providing relief to many patients and helping them avoid or postpone costly and more invasive surgery. The injections relieve pain by reducing the swelling and inflammation around the nerve roots caused by conditions such as spinal stenosis, herniated discs, and arthritis.

At The Christ Hospital in Cincinnati, Ohio, primary care doctors and neurosurgeons, who often refer patients to interventional radiologists for ESIs, were so impressed with the clinical results of the injections for back pain that they asked the radiologists if they would be willing to use them to treat neck pain as well. The result was a study of 161 patients with neck pain that found translaminar cervical ESIs to be a safe procedure with excellent clinical results in short-term follow-up.

The lead author of the paper, William M. Strub, MD, of the department of radiology at the University of Cincinnati, presented the results at the 32nd annual scientific meeting of the Society of Interventional Radiology (SIR). Strub was one of several radiologists to present findings on new back and neck interventions at the meeting.

In Strub’s report, the patients had neck pain due to arthritis, disc bulging, or spinal stenosis. A small percentage of the patients had prior cervical spine surgery.

“Some pain studies choose to look at their results from treating pain that is isolated [with] a specific condition, but we took all patients [who] presented with neck pain,” Strub says.

The interventional radiologists chose a translaminar (posterior) approach rather than the more conventional transforaminal (anterior) approach because they felt it was safer. Any procedure has risks, Strub says, but the inherent risks appeared to be lower with the translaminar approach.

“The group began performing cervical ESIs in 2003. The transforaminal approach was quickly abandoned due to reports in the literature of serious and catastrophic complications associated with it,” Strub says. The problem with the transforaminal approach, he says, “is there is a higher risk of injecting the steroid into small blood vessels that feed the spinal cord, and you can cause spinal cord infarction and paralysis.”

A retrospective analysis was performed on 69 men and 92 women, ranging in age from 26 to 82, who underwent cervical interlaminar ESIs between December 1, 2003, and April 30, 2006, at one of three institutions. The injections were performed by one of five interventional radiologists.

“An important aspect of this study,” Strub says, “is that we achieved excellent results at three different institutions among five different interventional radiologists. It is important to show results are transferable and reproducible, so a patient does not have to go to a designated physician at a particular institution to achieve the desired clinical outcome.”

Study patients received a cervical MRI exam prior to their injection to exclude any fracture or ligamentous injury as a cause of the pain and determine a safe level for the outpatient procedure, Strub says. Guided by fluoroscopy, the radiologists used a 22-gauge Tuohy epidural spinal needle to inject the steroid Kenalog at the C7-T1 level. “We found procedures performed at that level were more likely to result in improved pain relief for patients,” Strub says.

The radiologists injected 3 to 3.5 milliliters of a steroid-saline solution into patients, who were then monitored for a brief period before being discharged. After discharge, “the patients could return to normal activity level,” Strub says.

Epidural injections are usually done in sets of three. The patients in the study were typically not offered a second or third injection if they had no response to the first. “We didn’t see any point of continuing if it wasn’t working,” Strub says.

Ten days after the procedure, the patients were asked to rate their pain relief on a four-level scale with 0 being no relief; 1, minor or minimal relief; 2, some relief; and 3, substantial relief. After one injection, 81% reported pain relief, and 35% rated it as substantial.

A total of 280 injections were performed. Eighty-seven patients (54%) underwent the second, and 32 (20%) underwent the third procedure. The injections were given approximately four weeks apart.

Only minor complications in approximately 5% of patients were observed. They included weight gain, difficulty sleeping, facial flushing, hot flashes, and emotional lability (moodiness), which are typical of steroid injections. Thirteen patients (8%) had surgery after their second or third injections.

The researchers found that patients with multilevel degenerative changes were more likely to report improved pain relief than those who presented with single-level degenerative changes such as disc bulging, Strub says. Patients who showed radicular symptoms in the hand/finger also benefited from the procedure. However, the study found that those patients who needed narcotics for pain relief did not benefit as much from the injections as those who could control their pain with nonsteroidal anti-inflammatories such as ibuprofen, Strub says. “Although we don’t have any data to support the claim, we suspect that the pain is so severe in these patients that the injections won’t help,” he says.

Knowing which patients may benefit is helpful, Strub says, because “if you have a patient who said, ‘Ibuprofen doesn’t control the pain, and I need to take narcotics,’ you can say from the beginning that ‘you’re probably not going to experience as much pain relief from the injections as other patients.’”

The researchers found it didn’t matter how long the patient had been suffering from the pain. “We did not observe any difference with duration of symptoms with regard to the clinical response,” Strub says. “If the patients had symptoms for six months or six weeks, their pain relief was similar.” The median duration of symptoms before the procedure was performed was four months.

The study did not look at the long-term results of ESIs. “What we don’t know is if, years from now, we’re keeping patients from having surgery,” says Strub, who is hoping to have the research published in the Journal of Vascular and Interventional Radiology.

Strub believes ESIs are a good procedure for patients who may not be candidates or ready for cervical spine surgery. Also, he says, the study shows that the translaminar approach is a safe procedure. “Future comparative studies may show you don’t need to do the transforaminal approach anymore,” Strub adds.

Roughly 10% to 15% of the population suffers from neck pain, Strub says. “Many people say that it limits their ability to work and participate in recreational activities,” he says.

While not new, Strub believes cervical ESIs are underpublicized. “The pain management field is traditionally dominated by physicians in anesthesia or physical medicine and rehabilitation,” he says. “With an excellent clinical support staff, performing ESIs offers a significant area of growth opportunity for radiology practices.”

Percutaneous Vertebroplasty (PV): Four Years’ Experience
Another paper presented at SIR discussed the follow-up on 880 cases of PV, with follow-up as much as four years later. Giovanni Carlo Anselmetti, MD, of the Institute for Cancer Research and Treatment in Torino, Italy, reported on a large-scale study of patients suffering from back pain who underwent PV over a four-year period starting in August 2002. “To the best of my knowledge, this was the largest prospective study that has been done,” Anselmetti said.

The study showed that vertebroplasty is a safe, effective, minimally invasive procedure, even if it is applied on a large series of patients and more than three levels are treated in the same session, Anselmetti said. Vertebroplasty is performed by injecting an orthopedic cement mixture through a needle into the fractured bone.

Anselmetti said that many physicians believe vertebroplasty increases the risk of a new fracture in patients with osteoporosis. His data suggest the opposite.

The study looked at 880 patients—including 675 women with a mean age of 70.1—with painful vertebral collapse due to osteoporosis, metastases, myeloma, symptomatic angioma, or trauma who were not responding to conservative medical therapy of at least three months. Patients were treated in a same-day surgery environment, typically in the morning, and discharged in the afternoon.

Using a visual analog scale, with 0 being no pain and 10 being the worst pain possible, the researchers considered a good clinical outcome to be a drop equal to more than two points. They obtained that result in 100% of patients with symptomatic vertebral angioma; 95.7% in patients with osteoporosis; 95.5% in patients with traumatic fracture; 89.9% in patients with vertebral metastases; and 91.7% in patients with myeloma. The follow-up with patients varied from three to 51 months.

Anselmetti said patients who have back pain caused by vertebral collapse can benefit from vertebroplasty even if the vertebral fracture is more than three years old. Also, he said, vertebroplasty is a therapy for back pain, not only for osteoporosis or neoplastic disease but also for patients who have new fractures or metastases in other vertebrae.

Vertebroplasty is normally performed under digital fluoroscopy in the angiographic suite, Anselmetti said. However, in more difficult cases, CT guidance can be employed. “Actually,” he said, “state of the art is digital fluoroscopy in the angiographic suite with three-dimensional CT rotational acquisition built together. This allows the perfect real-time monitoring of the digital fluoroscopy, plus the precise localization of the vertebroplasty needle within the pedicle and vertebral body of CT, thus reducing the risk of complications, such as spinal cord damage from the needle, bone cement leakage, and pulmonary embolism.”

Although Anselmetti’s abstract was on 880 consecutive patients, he spoke about more than 1,000 consecutive patients as the SIR committee had asked him to update his data.

— Beth W. Orenstein is a freelance medical writer in Northampton, Pa.

Percutaneous Spinal Stabilization System
Also at the Society of Interventional Radiology meeting, J. Kevin McGraw, MD, FSIR, codirector of interventional radiology at Riverside Methodist Hospital in Columbus, Ohio, talked about a device that shows promise for stabilizing the spine and alleviating pain without open spinal fusion surgery.

The device is called Vertebral Percutaneous Interbody Nail (V-PIN), a series of curved hollow nitinol rods that are percutaneously inserted across the disc space to stabilize adjacent vertebral bodies. McGraw is working on the microinvasive, patent-pending device with Hatch Medical, a medical device incubator and technology brokerage firm based in Duluth, Ga.

McGraw said the device has been successfully placed in two cadaver spines and eight spine models to stabilize 10 disc spaces. The V-PINs were placed through four 10-gauge needle punctures. Each procedure took approximately one hour, according to McGraw.

The procedure could probably be done under local anesthesia, McGraw said, but it would more likely be performed under general anesthesia to limit any patient motion. It is a same-day procedure, he said.

The next hurdle is to conduct mechanical fatigue testing and seek FDA approval. “We conducted finite element analysis computer modeling with the Georgia Institute of Technology in Atlanta, and it passed that. Now we need to put the device in a model that bends it back and forth several million times to make sure that it doesn’t break. What that does is simulate the normal load on the human spine. Once we have that, we can seek FDA approval for human implantation,” McGraw said. “It’s hard to say when the device might become clinically available. It all depends on what the FDA requires.”

While additional studies are necessary, the initial results are promising, McGraw said. More than $4 billion is spent annually on surgical treatment for back pain. Degenerative disc disease is a common problem, and if this device could help patients avoid surgical fusion, it would be advantageous, McGraw said.

— BWO