Post–Vertebral Augmentation Back Pain: Evaluation and Management

Patient Selection

Our institutional review board approved the study, and Health Insurance Portability and Accountability Act—compliant practices were used throughout our investigation. We evaluated 124 consecutive patients who underwent vertebral augmentation for painful osteoporotic vertebral compression fractures at our institution retrospectively during a 2-year period.

All of these patients were referred for a vertebral compression fracture consultation at our institution after a thorough clinical evaluation, including either MR imaging or skeletal scintigraphy and CT of the spine, by their clinicians, and demonstrated the presence of ≥1 osteoporotic vertebral compression fracture as the possible cause of their back pain symptoms. Most of these vertebral compression fractures were subacute (6–12 weeks after the development of back pain symptoms), and these patients were not responding to conservative management with bed rest, analgesics, or orthosis. After an additional detailed clinical evaluation and fluoroscopic examination at the time of consultation, these patients were determined to be candidates for vertebral augmentation. All patients undergoing vertebral augmentation were subsequently evaluated after their procedures at standard time intervals (3 weeks postprocedure, 3 months postprocedure, and 1 year postprocedure) to assess patient outcome and provide additional patient management. In those patients with recurrent or persistent post–vertebral augmentation pain, the source of pain and the efficacy of subsequent spine-injection treatments were assessed.

Vertebral Augmentation Technique

The vertebral augmentation procedures were performed in an interventional radiology suite by using a biplane fluoroscopy unit (Integris V5000; Philips Medical Systems, Eindhoven, the Netherlands) with pulsed fluoroscopy at a rate of 7.5 pulses/second. The procedures were performed by an experienced interventional neuroradiologist under strict aseptic technique and local 2% anesthesia at the puncture site, with administration of the local anesthetic agent to the level of the periosteal surface. All patients were sedated with either intravenous propofol or midazolam (Versed) and fentanyl and were monitored by an anesthesiologist. Patients underwent either kyphoplasty or vertebroplasty by using bilateral or unilateral approaches with transpedicular or parapedicular access to treat vertebral compression fractures. Vertebroplasty was performed in patients whose vertebral body fractures showed only mild height loss, in patients with upper thoracic (T1 through T6) vertebral compression fractures, and in situations in which extensive patient comorbidities allowed only mild sedation to be administered. We used a 10-cm-long 10.5-ga bone needle for the vertebroplasty procedure and coaxial cannulas for cement injection.

Kyphoplasty was performed in patients whose vertebral compression fractures demonstrated at least 20% height loss, vertebral compression deformities with near-complete height loss (vertebra plana configuration), and vertebral compression deformities with significant avascular necrosis and endplate deformities or defects. Either 8- or 10-ga bone-access needles were used for kyphoplasty, depending on the size of the vertebral pedicle. Inflatable balloon tamps were used for the purpose of cavity creation and vertebral endplate remodeling in all of the patients undergoing kyphoplasty. Cement injection with commercially available polymethylmethacrylate bone cement (CONCERT Spine VR, Advanced Biomaterial Systems, Chatham, New Jersey) was performed by a hand-injection technique with a plunger by using coaxial bone-filler cannulas with both vertebral augmentation techniques by using detailed fluoroscopic monitoring. End points for termination of cement injection included satisfactory filling of the anterior two-thirds of the vertebral body or satisfactory cement filling of a large cleft or cement beginning to encroach upon the disk-endplate interface or basivertebral plexus. Cement volumes averaged 2.3 mL in the thoracic spine and 3.5 mL in the lumbar spine. Intraoperative-procedure time averaged approximately 20 minutes per level treated. The skin incision site was secured with Steri-Strip bandages (Nexcare 3M, Maplewood, Minnesota). All patients were monitored and recovered for 3 hours after their procedure. Most of these procedures were performed on an outpatient basis, with inpatient procedures performed in patients in whom a vertebral compression fracture was subsequently identified as the source of their abdominal or chest pain, in patients with intractable back pain, or in patients requiring transient correction of their anticoagulation status.

Pain Management

All patients were routinely evaluated and examined in the clinic at 3 weeks, 3 months, and 1 year after their vertebral augmentation procedure by the same operator who performed the initial vertebral augmentation procedure and by a nurse practitioner. This evaluation included a medical history, pain diagram with a numeric pain scale from 0 to 10, and a physical examination. Patient history was obtained by the nurse practitioner, and the pain diagram and numeric pain score was reported and provided by each patient. Patients with any type of back pain after the procedure were examined under fluoroscopy, by the same operator who performed their initial vertebral augmentation procedure, to better assess the postoperative site, assess the presence of a new vertebral compression fracture, or identify the site of pain along the spinal axis. Patients with vertebral body-related or vertebrogenic pain and a suspected vertebral compression fracture were referred for MR imaging to assess the presence of a new vertebral compression fracture. Those patients with a vertebrogenic pain source, focal palpable midline spinal tenderness, and a new vertebral compression deformity were considered to have a new vertebral compression fracture.

Patients with facet joint- or SIJ-related pain had pain diagrams that lateralized the side of pain to the affected joint or joints. These patients had focal palpable tenderness over the affected joint or joints. Those patients in whom the facet joint or SIJ was identified as a potential pain generator were subsequently scheduled for therapeutic injection of the affected joint (Figs 1 and 2). These procedures were performed on an outpatient basis by an experienced interventional neuroradiologist using either fluoroscopic or CT fluoroscopic guidance. A 22-ga spinal needle was advanced into the affected joint under imaging guidance. Arthrography was then performed with 1–3 mL of iodinated low-osmolar contrast media to confirm the intra-articular location of the needle tip. The joint was subsequently injected with 1–3 mL of a mixture of 2 mL (80 mg) of methylprednisolone and 3 mL of 0.5% bupivacaine. This volume of injectant allowed both intra- and periarticular distribution of the medication in all patients who were treated. The patient was questioned regarding pain provocation at the time of joint injection, and the response was documented. All patients were monitored and recovered for 30 minutes before discharge.

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Fig 1.

CT-guided unilateral facet joint injection. The patient is a 97-year-old woman (patient 19 in Table 1) with recurrent back pain after T10 and T11 vertebral augmentation. Her initial back pain symptoms were localized to the right upper lumbar facet joints under fluoroscopic evaluation. She was pain-free after undergoing right L1-L2 and L2-L3 facet joint injections 2 weeks after vertebral augmentation. She returned 11 months after her vertebral augmentation procedure for new low-back-pain symptoms that localized to her SIJs and responded to bilateral SIJ injections.

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Fig 2.

CT-guided bilateral SIJ injection. This 74-year-old woman (patient 28 in Table 1) had recurrent low back pain after T12 vertebral augmentation. On evaluation, including a pain diagram and fluoroscopic examination, her pain localized to her SIJs. Her T12 level revealed no evidence of palpable tenderness, and there was no new vertebral compression fracture. She became pain-free after 2 sessions of bilateral SIJ injection 6 weeks and 7.5 months after T12 vertebral augmentation.

Radio-frequency neurolysis was performed in patients who showed a favorable but short-term response, 2–4 weeks, to facet or SIJ injection.

In 8 patients with thoracic or lumbar facet-related pain, diagnostic median branch blocks were required before proceeding with radio-frequency neurolysis. Sacral radio-frequency neurolysis was performed in 2 patients who experienced temporary pain relief following their SIJ injections. These 2 patients showed a favorable pain response to diagnostic anesthetic injections in their SIJs before undergoing sacral radio-frequency neurolysis with a bipolar technique and treatment of the dorsal branches of S1, S2, and S3 as well as monopolar treatment at L5.

All 29 patients were seen in follow-up to assess their response to treatment. The patients were again required to complete a pain diagram and a numeric pain scale at the time of their evaluation. All patients were referred for outpatient physical therapy at facilities close to their homes, either after their 3-week evaluation or after their spine-injection procedures. Physical therapy was directed at spine rehabilitation, with core muscle strengthening, gait, and balance training. Additionally, patients with SIJ pain underwent pelvic and sacroiliac stabilization exercises and maneuvers as part of their physical therapy regimen.

Statistics

Because some patients underwent multiple vertebral augmentation procedures and multiple joint injections, we decided to use the averages of each vertebral body treatment and joint injection treatment to compare the level of joint injection with vertebral augmentation levels. Each vertebra was assigned a number starting from 1 for C1 to 24 for L5 and 25 for any sacral region (S1-S5 or SIJ). The average of the locations augmented was compared with the average of the locations that were treated for post–vertebral augmentation pain by using a paired t test, and the difference and confidence interval for the difference were reported. A P value < .05 was considered significant. The Mann-Whitney U test was used for any unpaired comparison without normal distribution. The normality of the distribution was assessed by the D'Agostino-Pearson omnibus test (GraphPad Prism, Version 5.02 for Windows; GraphPad Software, San Diego California; www.graphpad.com).