Treatment of multilevel degenerative disc disease with intradiscal electrothermal therapy.
Article Type: Case study
Subject: Spinal diseases (Case studies)
Spinal diseases (Care and treatment)
Spinal diseases (Diagnosis)
Spinal diseases (Patient outcomes)
Spinal diseases (Development and progression)
Electrotherapeutics (Case studies)
Electrotherapeutics (Usage)
Electrotherapeutics (Patient outcomes)
Author: Malik, K.
Pub Date: 04/01/2007
Publication: Name: Anaesthesia and Intensive Care Publisher: Australian Society of Anaesthetists Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2007 Australian Society of Anaesthetists ISSN: 0310-057X
Issue: Date: April, 2007 Source Volume: 35 Source Issue: 2
Geographic: Geographic Scope: United States Geographic Code: 1USA United States
Accession Number: 188796856
Full Text: SUMMARY

Intradiscal electrothermal therapy is a frequently performed procedure for the pain of internal disc disruption. It is typically performed on one to two discs, the discal treatment is followed by a long period of rest and rehabilitation. In patients with multilevel disc disease, intradiscal electrothermal therapy is either not contemplated or only one to two discs are treated at a time. This approach therefore either denies the patients the potential benefits of intradiscal electrothermal therapy or significantly prolongs the period of pain and disability.

A 25 year-old female patient printed with internal disc disruption at four lumbar disc levels diagnosed by provocative discography and post discography CT scan. All the discs were treated simultaneously by intradiscal electrothermal therapy. The patient tolerated the procedure well and responded favourably with significant and prolonged decrease in her symptoms. She reported sustained reduction in her pain and showed no clinical evidence of early neurological or infectious complications during 18 months of follow-up.

This report indicates that intradiscal electrothermal therapy can be performed at multiple levels at a single sitting, compared to intradiscal electrothermal therapy performed at one to two discs at a time, this approach may obviate the need for surgery and may reduce the duration of pain and disability incurred. However, the influence of multilevel intradiscal electrothermal therapy on long-term complications or outcome is not known.

Key Words: lumbar disc disruption, intradiscal electrothermal therapy, analgesia

**********

Intradiscal electrothermal therapy (IDET) is a minimally invasive, albeit controversial treatment for low back pain (LBP) of discogenic origin. It involves heating of the painful disc by a thermal coil (1,2). After thermal treatments of the discs, a period of rest and rehabilitation typically follows that can last for several months. Because of the potential risks of the IDET, it is commonly performed only on one or two disc levels at a time. There is no report of IDET being performed simultaneously at more than three discs (3,4). Patients with multilevel disc disease are considered either not suitable for this procedure, or only one to two discs are treated at a time interspersed by a long period of rest and rehabilitation. This strategy may significantly prolong the pain and disability, deny these patients the potential benefits of IDET and may expose them to spinal surgery, which has its own risks. A case is reported here where IDET was performed at four levels at a single sitting, in an effort to shorten the overall treatment time and reduce the period of pain and disability.

CASE HISTORY

The patient was a 25-year-old female who presented with a three-week history of low back pain, which radiated down her right leg. She worked as a waitress in a local restaurant and apart from her recent pain, was in good health with no history of alcohol or drug abuse. For this pain she was taking acetaminophen/ hydrocodone (Norco[R], Watson Laboratories, Corona CA, U.S.A.) 325/5 mg six to eight tablets a day, ibuprofen 800 mg three tablets a day and cyclobenzaprine (Flexril[R], Merck & Co. West Point PA, U.S.A.) 10 mg three tablets a day. She rated her pain as 9/10 on a numeric rating scale (NRS; where 0 corresponded to "no pain at all" and 10 corresponded to the "most severe pain imaginable"). Clinical examination revealed diffuse tenderness over the lumbar spinous processes and severe limitation of range of motion of her lower back. She had a positive straight leg raise (SLR) test on the right side and neurological examination of both her lower extremities was normal. Magnetic resonance imaging (MRI) showed herniated L4-5 and L5-S1 discs and except for the L1-2 disc, showed desiccation of all her lumbar discs. She was diagnosed with right-sided lumbar radiculopathy secondary to L4-5 and L5-S1 herniated discs.

[FIGURE 1 OMITTED]

[FIGURE 2 OMITTED]

Over the course of the next three months she received three lumbar epidural steroid injections, underwent physical therapy and continued her usual dose of acetaminophen/hydrocodone, ibuprofen and cyclobenzaprine. She was off work throughout this time and remained in significant pain (8-9/10: NRS). Over the course of the next few months, her pain gradually became axial and did not radiate to her right leg. For the next 16 months she continued with the physical therapy, analgesic medications and remained off work with no improvement in her pain levels. A second lumbar spine MRI was obtained (18 months after the initial MRI) which showed resolution of L4-5 and L5-S1 herniated discs. The desiccated appearance of the four lower lumbar discs however, remained unchanged. Lumbar discography was performed at 22 months after the onset of her symptoms. On provocative testing, except at L1-2 disc, she experienced severe concordant pain at all lumbar discs. Post-discography computerised tomography (CT) scan showed tears extending to the outer annulus (grade 4 and 5) at all the discs levels, except the L1-2 disc. She was diagnosed with internal disc disruption (IDD) of the lower four lumbar discs.

[FIGURE 3 OMITTED]

Multilevel IDET was offered and informed consent was obtained. Possible risks of the procedure were discussed, including increased risk of infection, spinal instability and unknown long-term effects with treatment of multiple disc levels. A single IDET catheter was placed in each disc (L5-S1, 1,4-5, 1,3-4 and L2-3) and catheter position along the posterior annulus was confirmed by fluoroscopy. Each disc was then treated for 17 minutes and the catheter temperature was incrementally raised to 90[degrees]C. The entire procedure was completed in about two hours. The patient tolerated the procedure well and she was discharged home in good condition wearing a lumbar brace and with instructions for activity limitation. After eight weeks of lumbar immobility and activity limitation, a program of progressive rehabilitative exercises was initiated that lasted for another four months.

[FIGURE 4a OMITTED]

[FIGURE 4b OMITTED]

[FIGURE 5a OMITTED]

[FIGURE 5b OMITTED]

[FIGURE 6 OMITTED]

At the two-week and six-week post-procedure visits, the patient remained in severe pain (NRS, 8/10) and continued the use of acetaminophen/hydrocodone (six to eight tablets a day) and ibuprofen (800 mg three tablets a day). At the 12-week follow-up visit however, she reported improvement in her pain (NRS 4-5/10) and had stopped taking the acetaminophen and was taking occasional ibuprofen. For the next several months her pain level steadily declined and at the 18-month follow-up visit she had minimal back discomfort (NRS 2-3/10). She was taking occasional over-the-counter analgesics and was back to her regular job. The neurological examination of her lower extremities remained normal throughout this time, she showed improved range of motion of her lower back over time and there remained no signs or symptoms suggestive of discal infection.

DISCUSSION

Low back pain is a significant source of morbidity and disability and healthcare costs related to back disorders amount to billions of dollars each year (5). Discogenic pain secondary to IDD is a common problem and may account for 40% of all pain from low back disorders (6). Cellular dysfunction and increased catabolic activity in the nucleus pulposus results in the loss of nuclear proteoglycan and water content. Dehydration of the nucleus pulposus reduces its hydrostatic pressure and exposes the annulus fibrosus to direct compressive forces, which eventually results in annular failure and fissuring. The inner layers of the annulus fibrosus are normally avascular and lack innervation. Ingrowth of granulation tissue, blood vessels and nociceptive nerve fibers, along the annular fissures, may result in a disc that is highly vascular and richly innervated (7). Distortion of these annular neo-nociceptors, which are presensitised by exposure to nuclear chemokines and cytokines, is thought to be responsible for pain generation (8). Low back pain, which is often worse with axial loading, is the most prominent symptom in these patients; signs and symptoms of spinal nerve root irritation are usually absent (9). The clinical course of IDD is typically chronic and resistant to conservative therapy (9). Nucleus pulposus desiccation and annular tearing may appear as loss of nucleus pulposus signal intensity and annular high intensity zones (HIZ) on MR images. Although subtle, these may be the only MRI findings discernible in these patients. Concordant pain reproduction during provocative discography remains currently the only test available to confirm the presence of IDD.

The IDET procedure involves placement of a heating coil inside the painful disc, along its posterior annulus, which is then incrementally heated for 17 minutes to a maximum temperature of 90[degrees]C. After discal treatment, a period of lumbar bracing, activity restriction and progressive rehabilitative exercises follows, that can last for four to six months. The mechanisms by which IDET relieves pain are speculative and are poorly understood. They have been described as coagulation of the neo-nociceptive pain fibers, repair of annular tears and remodelling and shrinkage of the annular collagen (8,10). Although a controversial procedure, IDET has been promoted as a safe and minimally invasive treatment for IDD and an alternative to spinal fusion surgery(1-4,8). Outcome studies of IDET are mostly observational and the results are highly heterogeneous, ranging from excellent to no benefit at all. A recently published meta-analysis of the published literature on IDET reported the overall efficacy and safety of the procedure (11). Although placebo effect of IDET cannot be ruled out, one controlled study showed that effectiveness of IDET cannot be wholly attributed to the placebo response (12). Due to its controversial nature and conflicting evidence of its efficacy, most third party payers do not support its use.

The reported complications from IDET are typically minor and resolve spontaneously. Serious complications such as nerve root injury, cauda equina syndrome, discitis and spinal instability have been reported but are rare (9). With average follow-up period of 12 to 24 months for most IDET related studies, no data is available on its long-term effects and its effects on disc integrity. Due to the potential risks of discitis and spinal instability, IDET is typically performed only on one or two painful discs (3,4). We encountered only one previous study where IDET was performed at three levels simultaneously (4). The results of multilevel IDET in these patients were compared to patients who had one or two discs treated at a time: although patients in the later group had a better outcome, the results differences were not statistically significant. There are no reports of IDET being performed at more than three discs at one time. It is unclear if the risk of discal infection will be higher if several discs are treated simultaneously and with strict aseptic precautions this risk should be no greater than one or two level IDET With accurate catheter positioning inside the disc and neurological assessment of the patient during the lesioning process, the potential for nerve injury should also be minimal. In vitro evidence suggests that no spinal instability resulted after IDET (13), with only a rare clinical report of possible spinal instability (11). The overall risk of spinal instability from simultaneous lesioning of several discs should also be insignificant.

The procedure was done at four discs levels at a single sitting. In this case, it was well tolerated and was completed in a relatively short period of time. Although a placebo effect cannot be ruled out, the patient experienced significant and sustained pain relief. She also showed no clinical evidence of neurological injury or disc infection for up to 18 months after the procedure. Although the possibility of longer-term complications cannot be ruled out, with strict aseptic precautions and meticulous technique (10,13), the theoretical risk of multilevel IDET should not be higher than IDET performed at one to two levels. Nevertheless, further clinical studies are needed to confirm the safety and efficacy of this practice.

ACKNOWLEDGEMENTS

I thank Andre DeWolf, Professor of Anesthesiology, Northwestern University, Evanston, Illinois for reviewing the manuscript.

REFERENCES

(1.) Saal JS, Saal JA. Management of chronic discogenic low back pain with a thermal intradiscal catheter. A preliminary report. Spine 2000; 25:382-388.

(2.) Saal JA, Saal JS. Intradiscal electrothermal treatment for chronic discogenic low back pain. prospective outcome study with a minimum 2-year follow-up. Spine 2002; 27:966-974.

(3.) Kapural L, Mekhail N, Korunda Z, Basali A. Intradiscal thermal annuloplasty for the treatment of lumbar discogenic pain in patients with multilevel degenerative disc disease. Anesth Analg 2004; 99:472-476.

(4.) Cohen SP, Larkin T, Abdi S, Chang A, Stojanovic M. Risk factors for failure and complications of intradiscal electrothermal therapy: A pilot study. Spine 2003; 28:1142-1147.

(5.) Andersson GB. Epidemiological features of low back pain. Lancet 1999; 354:581-585.

(6.) Schwarzer AC, Aprill CN, Derby R, Fortin J, Kine G, Bogduk N. The prevalence and clinical features of internal disc disruption in patients with chronic low back pain. Spine 1995; 20:1878-1883.

(7.) Freemont AJ, Peacock TE, Goupille P Nerve ingrowth into diseased intervertebral disc in chronic back pain. Lancet 1997; 350:178-181.

(8.) Saal JA, Saal JS. Intradiscal electrothermal therapy for the treatment of chronic discogenic low back pain. Clin Sports Med 2002;21:167-187.

(9.) Carey TS, Garrett JM, Jackman AM. Beyond the good prognosis. Examination of an inception cohort of patients with chronic low back pain. Spine 2000; 25:115-120.

(10.) Shah RV, Lutz GE, LeeJ, Doty SB, Rodeo S. Intradiskal electrothermal therapy: A preliminary histologic study. Arch Phys Med Rehabil 2001; 82:1230-1237.

(11.) Appleby D, Andersson G, Totta M. Meta-analysis of the efficacy and safety of Intradiscal Electrothermal Therapy (IDET). Pain Medicine 2006; 7:308-316.

(12.) Pauza KJ, Howell S, Dreyfuss P, Peloza JH, Dawson K, Bogduk N. A randomized, placebo-controlled trial of intradiscal electrothermal therapy for the treatment of discogenic low back pain. Spine J 2004; 4:27-35.

(13.) Lee J, Lutz GE, Campbell D, Rodeo SA, Wright T Stability of the lumbar spine after intradiscal electrothermal therapy. Arch Phys Med Rehabil 2001; 82:120-122.

K. MALIK * Department of Anesthesiology, Illinois Masonic Medical Center, Chicago, Illinois, Unite States of America

* M.D., Assistant Professor in Anesthesiology, Northwestern University, Evanston and Attending, Northwestern Memorial Hospital, Chicago.

Address for reprints: Dr K. Malik, Department of Anesthesiology, Northwestern Memorial Hospital, 251 Huron Street, Chicago, IL 60611, U.S.A.
Gale Copyright: Copyright 2007 Gale, Cengage Learning. All rights reserved.