24 Pain after Vertebral Augmentation

10.1055/b-0040-175473

24 Pain after Vertebral Augmentation

Scott Kreiner

Summary

Vertebral augmentation is a very effective procedure for relieving pain from a vertebral compression fracture (VCF). If pain persists after vertebral augmentation, the temporal relationship of the pain to the procedure is the most important factor in determining the cause of the pain. Pain immediately after the augmentation procedure is most commonly due to inadequate treatment of the fracture, complications associated with the procedure or an unrepaired additional fracture. Pain present before the fracture that returns or is perceived as worse is likely related to a degenerative or neoplastic process depending on the particular patient’s underlying condition. The most common cause of pain is an additional vertebral fracture and when this is suspected additional imaging should be obtained. Additional imaging should be obtained when infection or procedural complications are suspected. Any additional treatment will depend on the underlying disorder but can include antibiotics for injection and decompression with or without stabilization for symptomatic cement extravasation. Recurrent fracture of the incident fracture level can occur and should be thought of in patients with recurrent pain after vertebral augmentation. Vertebral body collapse and intervertebral disk degeneration places additional stress on the posterior elements and facet joints. This additional stress can cause pain which can be substantially decreased by facet injection or medial branch blocks. Facet related pain is common after VCFs and should be considered in a patient with persistent pain. The kyphosis seen with VCFs creates a sagittal imbalance that places more stress on the paraspinal musculature and can give rise to increase energy expenditure to maintain an upright posture and can cause pain. If the sagittal imbalance is severe enough it may require the patient to use a cane or a walker to ambulate. Although vertebral augmentation cannot entirely prevent vertebral deformity it can improve it and optimal restoration of vertebral body height can serve to improve patient function and to minimize abnormal stresses on the spine caused by excessive kyphosis.

24.1 Introduction

Vertebral augmentation is an effective treatment for pain caused by an acute compression fracture with 75 to 90% of patients obtaining good to excellent pain relief within 7 to 10 days after vertebral augmentation with or without cavity creation. ¹ ^– ³ For this reason, when providing this treatment both the physician and the patient should have reasonable expectations of pain improvement fairly quickly following the procedure. However, on occasion, the patient’s pain does not resolve, or they develop new pain at some point following the fracture.

Pain following vertebral augmentation, may or may not be associated with the compression fracture or the vertebral augmentation procedure. Most of the patients undergoing vertebral augmentation procedures have compression fractures related to osteoporosis or primary or secondary malignancy in the spine. These conditions are related to a host of comorbidities which are either directly or indirectly associated with other spine-related conditions that may cause pain.

The potential causes of spine pain after vertebral augmentation can be separated based on the timing of the pain in relation to the index procedure. For this reason, in patients who present with pain after the procedure, detailed questioning on exactly when the pain started, its quality, location, and aggravating/alleviating factors can help establish a diagnosis and develop an appropriate treatment plan.

In general, pain immediately surrounding the vertebral augmentation temporally is more likely related to the fracture, or complications of the procedure, or an adjacent level fracture. Pain that was present prior to the fracture is more likely related to degenerative changes that most often pre-date the presence of the VCF. Patients may also have preexisting conditions such as degenerative disk disease, facet arthropathy, or spinal stenosis that were painful and present prior to the fracture treatment but the more severe fracture pain overshadowed the secondary condition and following successful vertebral augmentation the pain from that secondary condition seemed to return or was, once again, noticed. Separating this from an additional fracture that was not seen on prior imaging or complications from the procedure itself is important.

24.2 Complications from Procedure

In the day or two following the procedure, it is reasonable to expect some postprocedural pain as a result of the incision and the needle traversing through the paraspinal soft tissue. In general, this pain should be limited to the first week following the procedure and usually within the first 3 to 4 days. If a patient returns to clinic with pain that is persisting over 10 days following the procedure, the most likely potential causes of the pain are inadequate treatment or refracture of the index fracture, and fractures at a level(s) other than the index level not identified prior to the procedure. There can also be some persistent pain at this time as the result of a fracture of a rib, pedicle, or transverse process during the procedure.

Patients who return to the office with complaints of persistent or worsening pain within the first 4 weeks after vertebral augmentation need assessment. If a thorough history and examination reveals severe, functionally limiting pain (≥7/10 on a numerical rating score), and/or the presence of “red flag” conditions, such as fever, chills, nausea, vomiting, inability to lie supine, new trauma, and/or pain with percussion to spinous process, then new imaging should be obtained.

Infection of the vertebral body and polymethyl methacrylate (PMMA) following vertebral augmentation (▶Fig. 24.1) is rare to the point that it is case-reportable but there should at least be a consideration of this possibility as it can be life threatening in the frail and elderly patients that frequently get VCFs. In patients who present in the postoperative period with systemic complaints of infection (fever, chills, lethargy) work-up should include laboratory work-up complete blood count (CBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and advanced imaging of the spine. Should this work-up be concerning for an infection, immediate aspiration/biopsy and culture of the area along with the long-term use of the appropriate antibiotics can be critical to the survival of the patient. ⁴ In the presence of neurologic deficit or spinal instability, prompt surgical treatment should be considered.

**Fig. 24.1** Vertebral osteomyelitis after vertebral augmentation. **(a)** T1-weighted fat saturated MRI with gadolinium one week after vertebroplasty demonstrates anterior epidural and paraspinal enhancing soft tissue and vertebral enhancement involving L1, T12, T11, and T10 (*white arrows* in a) indicating vertebral osteomyelitis. T1-weighted post-gadolinium axial MRI of the T10 vertebrae obtained one week after vertebroplasty demonstrates enhancing paraspinal inflammation with a cystic structure (*white arrow* in b) representing a paraspinal abscess. The short interval of time after the procedure does not correspond with the wide range and advanced appearance of the infection indicating that the infection may have already been present at the time of vertebroplasty. ⁵ Reproduced with permission from Syed et al 2009.

There are direct, procedure-related complications that can cause back pain and/or radicular pain after vertebral augmentation. These complications include fracture of the rib, pedicle, or transverse process, and extravasation of PMMA into locations where it is not desired (▶Fig. 24.2 and ▶Fig. 24.3). Some of the locations of extravasation that can cause symptoms include the neural foramen or spinal canal (▶Fig. 24.4 and ▶Fig. 24.5). Most if not all of these complications can be avoided if proper technique is used during the procedure. These technical aspects include not applying substantial torque by levering the needle once in the pedicle, carefully observing and managing the flow of the PMMA during its administration, and replacing the stylet into the introducer needle cannula once administration of the PMMA is complete.

**Fig. 24.2** Axial computed tomography (CT) image shows a fracture of the pedicle/vertebral body junction (*white arrow*). This was sustained during vertebral augmentation and the needle track through the lateral left pedicle can be seen (*white arrowheads*) along with the cement (*black arrows*).

**Fig. 24.3** Axial computed tomography (CT) image shows a fracture of the right transverse process (*white arrow*). This fracture occurred as a result of vertebral augmentation. Incidentally noted is extravasation of polymethyl methacrylate (PMMA) into the anterior epidural space (*white arrowheads*). This extravasation was asymptomatic.

**Fig. 24.4** Sagittal computed tomography (CT) scan of the thoracic spine showing polymethyl methacrylate (PMMA) leak into the epidural space (*black arrows*). ⁶ Adapted from Lopes and Lopes 2004.

**Fig. 24.5** Axial computed tomography (CT) scan of the thoracic spine showing extravasation of polymethyl methacrylate (PMMA) into the vertebral canal (*black arrows*) with compression of the spinal cord (*black arrowheads*) and nerve roots. Also note the presence of PMMA on the left side of the T6 vertebral body (area within black circle) which interfered with the lateral visualization of the PMMA injection. ⁶ Adapted from Lopes and Lopes 2004.

Treatment of these complications varies. Pedicle fracture occurs about 1% of the time, ⁷ ^– ⁹ and usually it does not require treatment if it is unilateral. It occurs most commonly in the thoracic spine where the pedicles are smaller, as compared with the lumbar spine. If the pedicle fracture is symptomatic it can be stabilized by injecting cement into it, a technique known as pediculoplasty. This technique is discussed in detail in Chapter 10. Should the patient have a radiculopathy related to the presence of PMMA in the foramen, a selective nerve root or epidural injection can be performed in an attempt to improve or alleviate the radicular symptoms. If the symptoms persist or if there is weakness related to compression of the nerve, surgical intervention may be required. Treatment of a PMMA “tail” in the paraspinal musculature (▶Fig. 24.6) is also determined by the symptoms. The overwhelming majority of patients are not symptomatic when cement follows the needle track into the paraspinal soft tissues. In the rare circumstance that the patient has substantial pain or discomfort that the provider feels is related to the paraspinal cement, a block with local anesthetic of the paraspinal muscles/PMMA should be diagnostic. If so, removal of the cement can be done with a small incision and fluoroscopic guidance. The cement can usually be identified under fluoro and removed with Ochsner-Kocher forceps or another type of clamping instrument.