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Transforaminal Epidural Injections Treat Leg and Back Pain

Epidural glucocorticoid injections are commonly given to patients with leg and/or back pain to relieve such pain and improve mobility without surgery. These steroid injections buy time to allow healing to occur and/or as an attempt to avoid surgery after other conservative (non-surgical) treatment approaches have failed.

During a transforaminal injection, a small-gauge blunt needle is inserted into the epidural space through the bony opening of the exiting nerve root (See Figure 1, Neuroforamen).

spinal nerve structures
Figure 1. Spinal nerve structures;
nerve root and neuroforamen

The needle is smaller in size than that used during a conventional epidural approach. The procedure is performed with the patient lying on their belly using fluoroscopic (real-time x-ray) guidance, which helps to prevent damage to the nerve root. A radiopaque dye is injected to enhance the fluoroscopic images and to confirm that the needle is properly placed (See Figure 2). This technique allows the glucocorticoid medicine to be placed closer to the irritated nerve root than using conventional interlaminar epidural approach. The exposure to radiation is minimal.

x-ray  shows spread of radiopaque dye to confirm correct needle placement
Figure 2. Transforaminal spread of the radiopaque
dye to confirm correct needle placement.

Spinal Conditions Treated and Outcomes
Indications include large disc herniations, foraminal stenosis, and lateral disc herniations. Patients with disc herniations and leg pain in most of the studies attained maximal improvement in 6 weeks. Interestingly, long-term success rates for transforaminal epidural glucocorticoid injections ranged from 71% to 84%.

Is More than One Injection Necessary?
As a rule, patients who obtained little relief from the first injection got little benefit from a second or third injection. Those patients with degenerative lumbar canal stenosis and patients who failed previous therapies may significantly improve standing and walking tolerance following transforaminal lumbar steroid injections. However, only about 15% to 61% of interventional pain management physicians perform transforaminal epidural injections. Interestingly, almost every single interventional pain management physician uses the conventional, interlaminar epidural injection.

Complications
Complications are rare but may include headaches, infections, blood pressure changes, bleeding, and discomfort at needle insertion site. Use of steroids rarely causes an increase in blood sugar and blood pressure, as well as leg swelling. The major complication, that being damage to a nerve root is very rare. However, using a blunt needle may even more reduce the risk of this complication.

Patient Sedated but Awake
The patient is sedated but awake through the intervention. It is important that the physician and patient communicate during the procedure. If significant leg pain is triggered during placement of the epidural needle or injection of the medication, the physician will immediately stop the procedure and check the position of the needle and the source of pain.

References:
1. Botwin T, Rittenberg B. Am J Phys Med Rehabil 2002; 81:898-895.

2. Vad VB, Bhat AL, Lutz GE, et al. Spine 2002; 27:11-16.

3. Lutz GE, Vad VB, Wisneski RJ. Arch Phys Med Rehabil 1998; 79:1362-1366.

Updated on: 09/07/12
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