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Minimally Invasive Procedures for Vertebral Compression Fractures


One in two women and one in five men aged >50 years will experience an osteoporotic fracture. These can result in substantial patient pain, morbidity, and healthcare utilization. A new osteoporotic vertebral fracture occurs every 22 s; 1.4 million occur worldwide every year. The majority are asymptomatic or result in tolerable symptoms, with only a third of patients with new fractures seeking medical attention. For the vast majority, acute back pain symptoms subside over a period of six to eight weeks as the fracture heals.

Vertebroplasty and kyphoplasty are minimally invasive image-guided procedures that involve the injection of polymethylmethacrylate (PMMA) into a fractured vertebral body ( Fig. 69.1 – 69.2 ). Most of these vertebral augmentation procedures are performed for a small subset of patients with symptomatic osteoporotic compression fractures that fail to respond to conservative medical therapy. Failure of medical therapy is variably defined but can be considered if pain persists at a level that severely compromises mobility or activities of daily living despite analgesic therapy or if unacceptable side effects such as confusion, sedation, or constipation occur as a result of medication doses required to reduce pain to tolerable levels. The first report of vertebral augmentation, published in 1987, was for neoplastic disease. As survival rates in cancer patients continue to improve, symptomatic neoplastic vertebral fractures or neoplastic vertebral tumors have increased in prevalence. A selected sub-group of these patients, particularly those with symptomatic fractures from multiple myeloma and metastasis that fail to respond to conservative therapy, also benefit from vertebral augmentation. The primary goal of vertebral augmentation is pain relief and enhanced functional status with the secondary goals of vertebral body stabilization in cases of fracture. Emerging population level evidence suggests a mortality benefit in patients treated with vertebral augmentation compared to conservative therapy.

Figure 69.1
Vertebroplasty involves the insertion of a needle into the vertebral body (A) with subsequent delivery of cement (B) into the vertebral body.

Figure 69.2
Kyphoplasty. Once vertebral body access is achieved (A), the inner ­stylet is removed, and a balloon tamp ­inflated within the vertebral body (B) to create a cavity within the bone (C) into which cement is delivered (D).

Indications and contraindications for vertebral augmentation are summarized in Box 69.1 .

BOX 69.1
Indications

  • 1

    Treatment of symptomatic osteoporotic vertebral body fractures that are refractory to conservative medical therapy

  • 2

    Treatment of symptomatic vertebral bodies that are refractory to medical therapy weakened or fractured because of neoplasia

Absolute contraindications

  • 1

    Active systemic infection, in particular, spinal infection

  • 2

    Uncorrectable bleeding diathesis

  • 3

    Insufficient cardiopulmonary health to safely tolerate sedation or general anesthesia

  • 4

    Myelopathy resulting from fracture retropulsion or epidural tumor extension

  • 5

    Known allergy to bone cement

Relative contraindications (should only be treated by experienced practitioners)

  • 1

    Marked loss of vertebral body height (greater than 75% height loss)

    • a

      Makes the procedure more difficult because there may be little space for cannula placement.

  • 2

    Vertebroplasty above T5

    • a

      Challenges because of the small size of the vertebral bodies and pedicles. The shoulders often limit fluoroscopic imaging at these levels.

  • 3

    Severe osteopenia resulting in poor visualization of osseous structures on fluoroscopy

    • a

      Increases the risk of improper needle placement and cement leakage. This can be overcome with computed tomography (CT) guidance.

  • 4

    Disruption of the posterior cortex

    • a

      Increases the risk of posterior cement leakage and, therefore, the risk of the spinal cord or nerve root compression. This phenomenon is frequently observed in burst fractures and neoplasms. The integrity of the posterior cortex was best evaluated using CT scanning.

  • 5

    Substantial canal narrowing (without neurologic dysfunction)

    • a

      Increases the risk that even a small amount of cement leakage will produce neurologic compromise.

  • 6

    Retropulsion of fracture fragments

    • a

      Risk of further canal compromise with vertebral augmentation, particularly if the posterior vertebral body wall is unstable.

  • 7

    Epidural extension of tumor

    • a

      Pathologic fractures result in significantly higher rates of spinal canal leakage than osteoporotic fractures.

Conservative Medical Therapy

Conservative therapy aims to reduce pain (with analgesics and/or bed rest), improvement in functional status (with orthotic devices and physical therapy), and prevention of future fractures (with vitamin D and calcium supplementation and bisphosphonate therapy).

While conservative management for those with mild pain and no limitation of function is appropriate, conservative ­treatment for those with more severe pain or limitation of function is not benign. In this cohort, conservative therapy often involves a period of bed rest, which may lead to undesirable side effects such as bone mass and muscle strength loss, decubitus ulceration, and venous thromboembolic disease (VTE), all of which can prolong the recovery period and result in loss of independence. Bone loss occurs at approximately 2% per week, muscle strength reduces by 10%–15%, and infectious complications can lead to septicemia and osteomyelitis. Reduced lung capacity can also predispose patients to pneumonia. Moreover, the presence of fracture or malignancy combined with bed rest elevates the risk of VTE in this cohort. Overall, complications of prolonged bed rest, combined with opioid narcotic use and associated side effects, can result in a vicious cycle of physical deconditioning, poor nutrition, and a subsequent increased risk of vertebral insufficiency.

Technical Aspects

The evaluation of patients for vertebral augmentation should identify patients likely to benefit from vertebral augmentation, as well as screen for contraindications. The decision to proceed with treatment must be based on a good history, physical examination, appropriate laboratory evaluation, and imaging, as summarized in Box 69.2 .

BOX 69.2
Pre-procedural Workup
*Rad AE, Kallmes DF. Pain relief following vertebroplasty in patients with and without localized tenderness on palpation. AJNR . 2008;29:1622-1626.

Identify those patients who will likely benefit from vertebral augmentation.

Screen for absolute contraindications.

Document failure of conventional medical therapy.

Symptoms

  • Fractures may occur with little or no trauma.

  • Deep pain with sudden onset

  • Midline location

  • Exacerbation by axial mechanical loading (worsening with standing or weight-bearing and often at least partially relieved by recumbency)

  • Exacerbation by motion (especially flexion)

  • Referred lateral radiation in a dermatomal pattern because of foraminal narrowing may be present.

Signs

  • Point tenderness at the spinous process of fractured vertebra Local signs may be absent.

  • Per Rad et al. up to 30% of patients may have subjective off-midline pain or tenderness over non-target vertebrae and still gain significant benefit.*

  • Localization to a specific level if possible is important in targeting treatment in patients with multiple compression fractures, some of which may be healed and do not require treatment. In difficult cases, examination can be performed with fluoroscopic assistance to localize the pain to a specific anatomic level.

Assess lower extremity neurologic function.

Laboratory evaluation

  • Screening for infection, coagulopathy, and metabolic abnormalities

  • Additional tests such as the performance of a urinalysis, electrocardiogram (ECG), and/or chest radiography are left to the discretion of the practitioner.

  • Imaging

  • The role is to confirm the clinical diagnosis, identify and assess the acuity of the painful fracture, identify potential difficulties, and plan the procedure.

  • Fracture imaging can be performed with magnetic resonance imaging (MRI) or nuclear scintigraphic bone scan to correlate symptoms with the vertebral level in question and confirm the acuity of the fracture.

  • MRI sequences include short tau inversion recovery or T2-weighted sequences with fat saturation. These sequences identified marrow edema, distinguishing between acute and chronic fractures. MRI also distinguishes between benign osteoporotic and pathologic fractures, and assesses the degree of fracture retropulsion, epidural tumor extension, spinal canal compromise, and compression of the spinal cord or nerve roots. Fracture clefts appear as a linear band of T1 hypointensity and T2 hypo- or hyperintensity within the vertebral body. Fluid signal intensity should be interpreted with caution, as some studies demonstrate persistent signals many months after the known incident fracture.

  • Nuclear scintigraphic bone scan or single-photon emission computed tomography (SPECT) combined with CT are the tests of choice. Acute fractures will take up the injected 99m Tc-MDP tracer at much higher concentrations; CT evaluates the bony integrity and spinal contents. In patients with pathologic fractures, CT also helps define the extent of sclerosis and posterior wall osteolysis, which predicts increased technical challenges associated with the procedure.

Sedation

Analgesia is typically necessary for vertebroplasty and kyphoplasty. In most cases, this is achieved with a combination of local anesthetic (e.g. lidocaine with bicarbonate or bupivacaine) and moderate sedation (intravenous midazolam and fentanyl). In some cases, the preferred approach is to utilize general anesthesia to provide adequate comfort and safety, particularly in patients who a However, having the patient awake allows feedback (e.g. increasing pain and neurologic dysfunction) that can alert the operator to potential complications. In all cases, continuous monitoring was performed with a minimum electrocardiogram (ECG), blood pressure measurements, and pulse oximetry. Drug delivery and monitoring are performed by anesthesiologists, nurse anesthetists, or certified nursing personnel. In patients with substantial preexisting respiratory or cardiac disease, an anesthesiologist can be asked to evaluate the patient and determine if monitored ­anesthesia care is warranted. The patient should not eat or drink for at least 4–6 h prior to the procedure.

Patient Positioning

Prone or oblique prone is the ideal patient position for thoracic and lumbar procedures. Besides the clear advantage of easy access, this position with proper cushion support under the upper chest and lower abdomen maximizes extension of the fractured segments, promoting kyphosis reduction. The patient’s arms should be placed sufficiently toward the head to keep them out of the path of the fluoroscope. Analgesia should be considered prior to placement on the table, as this part of the procedure may be quite painful. Care must be taken when transferring patients who are aged, osteoporotic, or with myelomatous infiltration, as this may result in new rib or vertebral fractures.

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