Facet Joint Osteoarthritis - Denervation for Low Back Pain

     


Facet Joint Back Pain

Low back pain constitutes the majority of musculoskeletal problems seen in chronic pain settings. The lifetime incidence of back pain has been reported to be between 54%-80% [1-3]. Lumbar facet joint pain is a syndrome in which the zygapophysial joints cause back pain. [1] It may account for as much as 14%-45% of those patients experiencing chronic LBP [4-6].

 



Facet Joint Osteoarthritis Treatment Options

Facet joint interventions, including intraarticular injections, medial branch nerve blocks, and neurotomy (radiofrequency and cryoneurolysis) are used to manage chronic facet-mediated spinal pain. Radiofrequency ablation to induce thermal necrosis of the facet neural fibers has been reported to provide significant pain reduction in patients for 6-12 months [7, 8]. However. complications from these techniques may occur. These include discomfort around the injection site, numbness of the skin, neuritis, pain from muscle spasm at injection site, permanent nerve pain and reactions to administered medications [9].

MR guided Focused Ultrasound provides a non-invasive method of facet denervation that provides pain relief without invasive procedural complications. [10]


ExAblate- MR guided Focused Ultrasound for Facet Joint Osteoarthritis

ExAblate uses MR guided Focused Ultrasound as a non-invasive thermal ablation technique to relieve back pain caused by facet joint osteoarthritis with minimum effect of the surrounding tissues. The palliative effect of MRgFUS is based on destruction of periosteal denervation by controlled heating.
 
The focused ultrasound energy is focused onto a small area of the painful joint, thermal energy is deposited resulting in protein denaturation at temperatures above 55 C for one second. Heating the peri-articular tissue beyond this threshold for a few seconds, results in local tissue necrosis, which causes denervation of the network of nerves around the facet joint. The FUS beam is then focused onto another facet and this new area is treated. The process is repeated until all the nerves causing the pain are destroyed. In clinical studies on average 5 [4-10] facet joints have been treated during one treatment session.



a Axial: Showing pretreatment beam angulation to avoid spinous process and spinal canal.   
b Sagittal: Showing pre-treatment beam angulation to avoid the spinous process
and spinal canal
 

Benefits of Focused Ultrasound for Facet Joint Osteoarthritis

The benefits of ExAblate for facet joint denervation include:

  • Non-invasive therapy for facet joint pain
  • No needles involved
  • No exposure to ionizing radiation (as in fluoroscopy)
  • All involved facet joints can be treated in one session
  • Real-time image control and thermal feedback minimize complications
  • An effective and safe thermal ablation technique for facet joint pain

 
In addition, MRI can help increase the diagnostic certainty of facet joint disease 


Clinical Results



Weeks, Platt and Gedroyc report on the safety and efficacy of eighteen patients treated with ExAblate with MRgFUS for facet joint lower back pain. [10]
The mean age of patients was 48.2 years and mean BMI was 28.2. The mean number of joints treated was five (4-10). Mean pain score, measured by 0-10 numerical rating scale (NRS), pre-treatment was 6.42 (average) and 7.96 (worst). A reduction in the NRS average pain score of 3.87 (60.2%) and NRS worst pain score of 4.08 (51.5%) was found at 6/12 months. This was associated with a 45.88% improvement in the low back pain dedicated Oswestry Disability Questionnaire score and a 61.90% reduction in the brief pain inventory (BPI) interference in life score questioner.

The findings confirmed the inherent safety of MRgFUS. There were no recorded treatment complications or related thermal side effects.
The safety and efficacy demonstrated that MRgFUS resulted in improvements in both pain scores and functional disability measures at each follow-up time point from 1 week post treatment to 6 months after treatment. These results are similar to those reported by treatment of RF denervation. 


Clinical Case: 35 Year Old Female, L4-L5, L5-S1 (Bilateral) Treated

      

Patient experienced significant pain relief following treatment with no adverse events


References

1. Manchikanti L, Singh V, Datta S, Cohen SP, Hirsch JA (2009). Comprehensive review of epidemiology, scope and impact of spinal pain. Pain Physician 12:35–70;

2. Quraishi NA, Taherzadeh O, McGregor AH, Hughes SPF, Anand P (2004) Correlation of nerve root pain with dermatomal sensory threshold and back pain with spinal movement in single level lumbar spondylosis. J Bone Joint Surg Br 86-B:74–80;

3. Woolf A, Pfleger B (2003) Burden of major musculoskeletal conditions. Bull World Health Organ 81:646–656

4. Boswell MV, Colson JD, Sehgal N, Dunbar EE, Epter R (2007) A systematic review of therapeutic facet joint interventions in chronic spinal pain. Pain Physician 10:229–253

5. Cohen SP, Williams KA, Kurihara C, Nguyen C, Shields C, Kim P, Griffith SR, Larkin TM, Crooks M, Williams N, Morlando B, Strassels SA (2010) Multicenter, randomized, comparative cost- effectiveness study comparing 0, 1, and 2 diagnostic medial branch (facet joint nerve) block treatment paradigms before lumbar facet radiofrequency denervation. Anaesthesiol 113:395–405

6. Van Zundert J, Mekhail N, Vanelderen P, van Kleef M (2010) Diagnostic medial branch blocks before lumbar radiofrequency zygapophysial (facet) joint denervation–benefit or burden? Anaesthesiol 113:276–278

7. Gallagher J, PL PV, Wedley JR, Harman W, Ryan P, Chikanza I (1994) Radiofrequency facet joint denervation in the treatment of low back pain: a prospective controlled double-blind study to assess its efficacy. Pain Clin 7:193–197

8. Dreyfuss P, Halbrook B, Pauza K, Joshi A, McLarty J, Bogduk N (2000) Efficacy and validity of radiofrequency neurotomy for chronic lumbar zygapophysial joint pain. Spine 25:1270–1277

9. Kornick C, Kramarich SS, Lamer TJ, Todd Sitzman B (2004) Complications of lumbar facet radiofrequency denervation. Spine 29:1352–1354

10. Weeks EM, Platt M, Gedroyc, W.MRI-guided focused ultrasound (MRgFUS) to treat facet joint osteoarthritis low back pain—case series of an innovative new technique European Society of Radiology 2012 DOI 10.1007/s00330-012-2628-6









 

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