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Minimally Invasive Interventional Spine Treatment – Part 1

Flouroscopically directed spinal injection techniques may improve the efficacy of physical therapy and functional restoration protocols.
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Minimally invasive interventional spine treatment has grown in importance during the past several years. In this first of a two-part series, we examine the common intradiscal procedures and spinal injections not involving the discs and we present the most common spinal procedures utilized to diagnose and treat spinal pain. Part 1 examines injections for diagnosing, localizing, and ultimately blocking spinal pain generators.

The patient diagnostic work-up should commence with a well-documented, detailed, and directed historical account, together with a focused physical examination of the involved body parts. Historical emphasis should be on the duration of symptoms, previous attempts at procedures, and the functional approach to their disability. The signs of symptom magnification and malingering should be noted and documented. Notwithstanding potential discomfort, a thorough functional, social, and psychological history should be reviewed with the patient. Selective imaging studies (e.g., plain radiographs, MRI, CT scan, myelography, bone scans) can be useful added screening aids in further evaluating the patient, when compared to the history and physical. During the evaluation, additional screening and diagnostic studies (such as laboratory work-up and electromyography) can be useful in determining the correct diagnosis, and possibly ruling out other diagnoses. Electrodiagnostic studies (i.e., EMG/NCS) are useful for detecting neurogenic changes, denervation activity, differentiating multiple root vs. plexus lesion involvement, as well as the extent or severity of these changes, and the level of involvement. Unlike imaging studies, electrodiagnostic studies provide electrophysiological information, which is helpful to the clinician in determining an accurate diagnosis. Lastly, diagnostic interventional procedures can be useful in providing valuable insight into the patient’s primary pain generator(s), anatomic defect(s), pain threshold, and psychological response to treatments given.1-14

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Role of Spinal Injections in Spinal-related Pain

The use of selective spinal injections in the treatment of spinal-related pain disorders have obvious diagnostic and therapeutic values for the affected patient. They involve discrete, well-controlled injection techniques directed at specific target sites in and around the spine, which usually involve the use of fluoroscopy to aid in the proper needle placement and in so doing, may help increase the accuracy and efficacy of the specific injection technique (see Figure 1). Spinal injections are an extremely useful adjunct to other clinical evaluation tools, in precisely diagnosing and localizing the clinically significant spinal pain generators. This technique is especially valuable for multilevel disc disease, suspected chemically-mediated symptoms (when demonstrated by imaging or electromyographic testing in situations with no obvious abnormalities), or in post-operative cases where anatomic boundaries are disrupted and imaging studies are difficult to interpret accurately. When combined with corticosteroids (which interfere with inflammatory mediators, membrane stabilization, and suppression of ectopic neuronal discharges) and other anesthetic solutions (which cause reversible nerve conduction block), they provide a dramatic therapeutic benefit. They provide a specific beneficial role for individuals by relieving pain and increasing the range of motion prior to, or during, the rehabilitative process and so allows the patient to participate more fully in the therapy program. These selective spinal injections are indicated specifically in the medically-stable patient and are considered outpatient, minimally-invasive, minor surgical procedures. For patients with failed back surgical syndrome (FBSS) and prior to proceeding with operative interventions (e.g., spinal fusion, microdiscectomy, or laminectomy and decompression), the coupling of injection procedures with an accurate history and physical exam, and the confirmation with the appropriate imaging and/or electrophysiologic study, can greatly assist the spinal surgeon and treating physician to make an informed decision regarding a more directed and efficient treatment program.

The goal of diagnostic selective bocks is to differentiate the qualitative and quantitative contributions of discogenic, radicular, and posterior element pain sources. Because of the required precision in needle localization—and technical difficulty in performing these procedures—the use of fluoroscopy and contrast dye is essential. Epidural injections are frequently performed without radiographic guidance, but incorrect needle placement can occur in up to 25% of cases, including subcutaneous, intraligamentous, and intravenous locations. Therefore, fluoroscopic visualization with an epidurogram, perisheathogram, or arthrogram is highly recommended, especially in postoperative cases. Pain reproduction during these procedures may also help to more accurately identify the painful structure. Typically, nonaffected nerve roots will not trigger as severe a pain response when mechanically irritated by a spinal needle or contrast dye. Often, comparison of pain levels prior to and after the injections — by patient verbalization, pain diaries, or visual analog scale — is very helpful in gauging the response to the anesthetic procedure. Afterwards, provocative maneuvers such as evaluating spinal range of motion, straight leg raise, and ambulatory capabilities pre- and post-injection may also assist in identifying a particular site as the actual pain source. Exaggerated or extreme pain behaviors during the procedure provide information regarding non-physiologic causes for pain.15-31

Diagnostic and Therapeutic Spinal Injections

Selective spinal injections are being performed with increasing frequency in the management of acute and chronic pain syndromes. A few of the most common indications for these diagnostic and therapeutic spinal procedures are noted as follows:

  • Spinal nerve radiculopathy;
  • Spinal stenosis;
  • Discogenic pain (i.e., symptomatic, internal disc disruption);
  • Contained, disc bulge, or protrusion vs. extruded or sequestered herniated disc;
  • Multilevel degenerative disc disease;
  • Facet joint arthropathy or associated facet joint nerve pain;
  • Sacroiliac joint pain dysfunction;
  • Failed back surgery syndrome (FBSS);
  • Epidural and/or perineural fibrosis/granulation with associated symptomatic pain;
  • Complex regional pain syndrome (CRPS) (formerly known as reflex sympathetic dystrophy, RSD).

Although numerous interventional procedures are used to treat spinal-related pain conditions, a few of the most common types of diagnostic and therapeutic spinal injections are noted as follows:

  • Epidural steroid injections (translaminar, transforaminal, caudal);
  • Facet joint nerve blocks and facet joint intra-articular injections;
  • Neurolytic and radiofrequency (RF) nerve ablation procedures;
  • Sacroiliac joint and other intra-articular joint injections;
  • Sympathetic ganglion nerve blocks;
  • Diagnostic discographic injections;

The following sections will briefly describe these interventional spine procedures in common use for spinal-related pain.32-50

Last updated on: December 13, 2011
First published on: November 1, 2006