Lumbar facet joint denervation technique [Neurosurgery Wiki]

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====== Lumbar facet joint denervation technique ======

It is unclear how effective [[RFD]] is at relieving [[LBP]]. [[NICE]] 2016 (NG59) guidance
((CG59 N. Low back pain and sciatica in over 16s: assessment and management. In: NICE, editor, 2016. Available at: http://nice.org.uk/guidance/ng59))
on [[LBP]] recommends [[RFD]] as a treatment option for people with suspected facetogenic LBP who fail to respond to [[conservative treatment]] and respond positively to [[medial branch]] blocks (MBBs). A subsequent (2017) Dutch study ([[MINT]]), found no benefit from the addition of RFD to an exercise program for people with LBP who had responded positively to a MBB
((Juch JNS, Maas ET, Ostelo R, et al. Effect of radiofrequency denervation on pain intensity among patients
with chronic low back pain: the mint randomized clinical trials. JAMA 2017; 318(1): 68–81.)).

The MINT study was heavily criticized for multiple reasons, including the utilization of a sub-optimal [[lumbar facet joint denervation]] [[technique]], which was inconsistently delivered
((Provenzano DA, Buvanendran A, de Leon-Casasola OA,
et al. Interpreting the MINT randomized trials evaluating radiofrequency ablation for lumbar facet and sacroiliac joint pain: a call from ASRA for better education, study
design, and performance. Reg Anesth Pain Med 2018;
43(1): 68–71.))
((Van Kuijk SMJ, Van Zundert J, Hans G, et al. Flawed
study design and incorrect presentation of data
negatively impact potentially useful interventional
treatments for patients with low back pain: a critical
review of JAMA’s MinT study. Pain Pract 2018; 18(3):
292–295.)).

The described technique of RFD varies between published studies
((Nath S, Nath CA and Pettersson K. Percutaneous lumbar zygapophysial (Facet) joint neurotomy using radiofrequency current, in the management of chronic low
back pain: a randomized double-blind trial. Spine 2008;
33(12): 1291–1297; discussion 1298.))
((Cohen SP, Doshi TL, Constantinescu OC, et al. Effectiveness of lumbar facet joint blocks and predictive value before radiofrequency denervation: the Facet Treatment
Study (FACTS), a randomized, controlled clinical trial.
Anesthesiology 2018; 129(3): 517–535.))
((Civelek E, Cansever T, Kabatas S, et al. Comparison of
effectiveness of facet joint injection and radiofrequency
denervation in chronic low back pain. Turk Neurosurg
2012; 22(2): 200–206.))
((Van Kleef M, Barendse GA, Kessels A, et al. Randomized trial of radiofrequency lumbar facet denervation for chronic low back pain. Spine 1999; 24(18): 1937–1942.)).

The British Pain Society (BPS) and Faculty of Pain Medicine (FPM) Standards of good practice for MBB injections and RF published in March 2014 provide the broad framework for delivery of RFD and patient selection but do not specify the technical detail of needle placement, lesion temperature, duration or choice of joint level
((Anaesthetists BPS & FPM of RCoA. Standards of
good practice for medial branch block injections and
radiofrequency denervation for low back pain. March
2014. Available at: https://www.britishpainsociety.org/
mediacentre/news/standards-of-good-practice-formedial-branch-block-injections-and-radiofrequencydenervation-for-low-back-pain/)).

The Spine Injection Society guidelines are widely adopted by most but not all practitioners. Furthermore, the technique is published in the society’s book and only available on payment of a fee
((Bogduk N (ed.) International spine intervention society
practice guideline for spinal diagnostic and treatment procedures. San Francisco, CA: International Spine Intervention Society, 2013.)).

===== Positioning the RF cannula =====
1. Identify the L5-S1 disc interspace.
2. Identify the L5 vertebral body.
3. Rotate the image intensifier laterally to visualise
the bony curvature between the transverse and
the articular process. Occasionally, the curvature is visible in the AP view and no lateral rotation is necessary.
4. Once the curvature is identified, tilt the image
intensifier inferiorly keeping the curvature
clearly in view.
5. Tilt the image intensifier so as to view curvature
as medially and inferiorly as possible.
6. Once the above view is achieved, local anaesthetic is infiltrated at the skin entry point. This
is in a line directly below curvature at lower border of transverse process of the same level.
7. Aim to contact bone below curvature.
8. Advance your RF cannula in a posterolateral
view needle at 4 o’clock or 8 o’clock depending
on right or left side. The target is the middle
two-fourth of the lateral aspect of the articular
process aiming to contact the medial branch
before it courses under the mammillo-accessory
ligament in a trajectory parallel to the nerve.
9. Once the RF cannula is in position, use the tunnel view to confirm needle in curvature on bone.
10. Use the superior (cranial tilt) view with needle
at 6 o’clock to assess depth of the cannula
((Nath S, Nath CA and Pettersson K. Percutaneous lumbar zygapophysial (Facet) joint neurotomy using radiofrequency current, in the management of chronic low
back pain: a randomized double-blind trial. Spine 2008;
33(12): 1291–1297; discussion 1298.)).
----
Be very familiar with the [[lumbar medial branch]] of the posterior primary ramus - this is your target!

For [[facet denervation]], target the medial branches at the levels you want to treat together with the medial branch to the level above. 


L1/L2 T12, L1, L2

L2/L3 L1 L2 L3 

L3/L4 L2, L3, L4

L4/L5 L3, L4, L5

L5/S1 L4, L5, S1 


----

In [[prone position]] on a [[radiolucent table]]; stand on the left side of the patient if you are right-handed and vice-versa if you are left-handed. With the [[C Arm]] image intensifier in the postero-anterior axis, obtain a clear view of the [[lumbar vertebra]]e; if necessary, adjust the position of the image intensifier so as to obliterate any double end-plates. 

This is done by angling the image intensifier, which is in the postero-anterior axis, very slightly caudally. This manoeuvre results in the lower border becoming a single line on X-ray screening 

{{doubleendplate.jpg|}}

Occasionally, the double-end plate is removed by moving the axis of the C-arm image intensifier very slightly cranially. The best place to start trying to locate the medial branch of the posterior primary ramus is the point where it enters the groove on the back of the vertebral lamina. 

For this you need to move the image intensifier from its initial postero-anterior axis (corrected for 'double end-plates') obliquely away from the patient so as to obtain a good view of the so-called 'Scottie dog'. Your preliminary target is the 'eye of the dog' 

{{::scottie_dog_eye.jpg?200|}} {{::scottie_dog_eye_xray.jpg|}}

Use a 25G needle to infiltrate the superficial tissues only; do not go down as far as bone, as you will anaesthetise the medial branch and be unable to locate it by stimulation. Insert a 22G, 100.5mm (5mm exposed tip) RF needle along the angle of the X-ray beam so as to hit the 'eye of the Scottie dog' in tunnel vision

 
Replace the RF needle stilette with the thermocouple electrode and try to locate the medial branch by sensory stimulation, using the following parameters on your machine: 

Frequency; 50Hz Pulse width; l ms Voltage; up to 0.5V 

NB If you only manage to locate the nerve at a voltage greater than 0.5V - keep looking! You are unlikely to produce an effective lesion here. 

If you cannot locate the nerve on bone, then slip forward off bone and into the groove close to the intervertebral foramen 

and try again. If you still cannot locate the nerve, advance deeper and very slowly checking the position of your needle in the lateral axis.

The tip of your needle must newer lie anterior to an imaginary line passing through the posterior margin of the intervertebral foramen

If you lesion anterior to this point, you run the double risk of causing neuritis and of damaging the motor root. As you gain experience in the technique, you may decide to slip forward into the groove from the 'eye of the Scottie dog' as a matter of routine. Locating the nerve in the groove means that you are using the shaft of the needle as opposed to its tip and many workers consider to be a better way of obtaining a permanent lesion (see chapter on 'The physics of radiofrequency'). Once you have achieved localisation by sensory stimulation, test for motor stimulation using the following parameters on your machine: 

Frequency; 2Hz Pulse width; I ms Voltage; double the sensory threshold but at least I V 

NB it is very common to see localised contractions around the needle area (due to stimulation of the Multifidus muscle by the motor component of the medial branch); these can safely be ignored. You are on the lookout for rhythmical contractions in the lower limb. Should these appear, reposition the needle. 

You are now ready to carry out a lesion. Preset the timer to 60 seconds. Preset the temperature maximum to 85°C. Remove the thermocouple electrode and inject l ml of 2% Lidocaine through the needle. Replace the electrode. Switch your machine to lesion mode and gradually increase the power, which will in turn cause a temperature rise. When the temperature reaches 80`C, switch the timer on, in order to create the lesion. When the lesion has been performed, remove the electrode and inject 1 ml of a mixture of 0.5% Bupivocaine plus a depot steroid preparation in order to reduce post procedure discomfort. 

__The medial branch of the L5 posterior primary ramus__ 

Your target here is slightly different. With the image intensifier in the postero-anterior axis, visualise the sacrum; your target is the junction between the superior articular process and the upper surface of the lateral part of the sacrum 

; very often you can locate the medial branch here without needing to move the image intensifier off the postero-anterior axis; instead, you may find it useful to angle your needle, departing from strict 'tunnel vision'. 

Hunt for the nerve as already outlined above. 

If you cannot locate the nerve on bone, then slip forward off bone and into the groove close to the intervertebral foramen and try again. If you still cannot locate the nerve, advance deeper and very slowly checking the position of your needle in the lateral axis. The tip of your needle must never lie anterior to an imaginary line passing through the posterior margin of the L5 intervertebral foramen.



If you lesion anterior to this point, you run the double risk of causing neuritis and of damaging the motor root. As you gain experience in the technique, you may decide to slip forward into the groove from bone as a matter of routine. Locating the nerve in the groove means that you are using the shaft of the needle as opposed to its tip and many workers consider to be a better way of obtaining a permanent lesion (see chapter on The science of radiofrequency'). 

__Branch from S1__ 

This lies just lateral to the Si foramen.



 You do not need a motor test at this point. 



----


Using diagnostic anesthetic blocks, the [[lumbar facet joint]] has been shown to be the primary cause of pain in approximately 15% of patients with chronic low back pain. 

Lumbar RFN can be very effective when performed in a rigorous manner in appropriately selected patients. Chronic back pain, mediated by the lumbar medial branches, can be stopped and patients fully restored to normal living, if treated with RFN ((MacVicar J, Borowczyk JM, MacVicar AM, Loughnan BM, Bogduk N. Lumbar medial
branch radiofrequency neurotomy in New Zealand. Pain Med. 2013 May;14(5):639-45. 
doi: 10.1111/pme.12000. Epub 2012 Dec 28. PubMed PMID: 23279154.)).

The prevalence of zygapophysial joint pain appears to be 7% in patients with failed back surgery syndrome. Patients with this condition can be treated with a radiofrequency neurotomy with a success rate of 58.8% ((Klessinger S. Zygapophysial joint pain in post lumbar surgery syndrome. The
efficacy of medial branch blocks and radiofrequency neurotomy. Pain Med. 2013
Mar;14(3):374-7. doi: 10.1111/pme.12012. Epub 2012 Dec 13. PubMed PMID: 23241083.)).

Radiofrequency neurotomy (RFN) of the lumbar medial branch innervating the zygapophysial joint has been shown to provide a significant decrease in pain in patients selected by dual comparative anesthetic blocks, but quantitative improvements in mobility have not been fully elucidated. A theoretical concern with RFN is that the multifidus muscle, a stabilizing paraspinal muscle, is also denervated during this procedure, which may have adverse effects on mobility and spine stability ((Stegemöller EL, Roper J, Hass CJ, Kennedy DJ. Changes in gait kinematics and
lower back muscle activity post-radiofrequency denervation of the zygapophysial
joint: a case study. Spine J. 2013 Oct 10. pii: S1529-9430(13)00747-X. doi:
10.1016/j.spinee.2013.06.061. [Epub ahead of print] PubMed PMID: 24120824.)).
----
In CLBP of facet origin, shifting the target of percutaneous radiofrequency to the facet joint capsule provides an easier technique with an extended period of pain relief compared to the medial dorsal branch of the facet joint
((Moussa WM, Khedr W. Percutaneous radiofrequency facet capsule denervation as
an alternative target in lumbar facet syndrome. Clin Neurol Neurosurg. 2016 Sep
5;150:96-104. doi: 10.1016/j.clineuro.2016.09.004. [Epub ahead of print] PubMed
PMID: 27618781.
)).