Description
Cluneal nerve blocks are used as a proposed treatment for individuals with cluneal nerve entrapment syndromes causing pain in the low back and buttocks. The superior and the middle cluneal nerves (SCN and MCN) are cutaneous nerves that are sensory and dominate sensation in the lumbar area and the buttocks, and entrapment of these nerves around the iliac crest can elicit low back pain. The superior cluneal nerve (SCN) provides sensory innervation to the areas of the posterior iliac crest and upper buttocks. It originates from the upper 3 lumbar spinal nerves (L1 – 3), passes through the thoracolumbar fascia, and can be entrapped at the osteofibrous orifice where it penetrates the thoracolumbar fascia. The anatomic and functional bases for the development of SCN entrapment neuropathy are a rigid fascial edge and stretching of the gluteus maximus muscle and skin over a large area during flexion of the hip joint. If the nerve is chronically subjected to stretching, the resulting tissue irritation, edema, inflammatory cell infiltration, and scarring can lead to entrapment. Low-back pain caused by SCN entrapment is induced and exacerbated by movements such as rising, sitting, and rolling over, and by prolonged sitting, standing, or walking. Although the etiology of SCN entrapment neuropathy remains unclear, the symptoms are low-back pain (buttock pain) and paresthesia in the area of SCN innervations. Diagnosis of SCN entrapment neuropathy requires a positive result after a SCN block. Cluneal nerve blocks are generally performed under fluoroscopy where the physician injects one or more anesthetic agents and/or steroids near an affected cluneal nerve or branch to control pain and inflammation or to aid in diagnosis and treatment. The block is intended to interrupt the conduction of pain impulses and minimize the neuropathic pain and paresthesia associated with the SCN entrapment.

Policy
Cluneal nerve injections or blocks for the treatment of low back pain is considered investigational and/or unproven and therefore considered NOT MEDICALLY NECESSARY.

Rationale
There is insufficient evidence pertaining to cluneal nerve blocks for the treatment of low back pain in the peer reviewed medical literature. Only one randomized controlled trial (RCT) (n = 20) was located and the remaining are small prospective uncontrolled studies and case reports. There are no professional society guidelines that address cluneal nerve blocks as a treatment for low back pain.

The only RCT (Nielsen et al. 2019) describes a novel ultrasound-guided superior cluneal nerve block technique for application in the management of postoperative pain after hip surgery as well as other clinical uses such as chronic lower back pain. The study was carried out as two separate investigations. First, dissection of 12 cadaver sides was conducted in order to test a novel superior cluneal nerve block technique. Second, this nerve block technique was applied in a randomized trial of 20 healthy volunteers. Initially, the LFC, the subcostal and the iliohypogastric nerves were blocked bilaterally. A transversalis fascia plane (TFP) block technique was used to block the iliohypogastric nerve. Subsequently, randomized, blinded superior cluneal nerve blocks were conducted with active block on one side and placebo block contralaterally. The results showed that successful anesthesia after the superior cluneal nerve block was achieved in 18 of 20 active sides (90%). The area of anesthesia after all successful superior cluneal nerve blocks was adjacent and posterior to the area anesthetized by the combined TFP and subcostal nerve blocks. The addition of the superior cluneal nerve block significantly increased the anesthetic coverage of the various types of hip surgery incisions. The authors concluded that the novel ultrasound-guided nerve block technique reliably anesthetizes the superior cluneal nerves. It anesthetizes the skin posterior to the area innervated by the iliohypogastric and subcostal nerves. It improves the anesthetic coverage of incisions used for hip surgery. Among potential indications, this new nerve block may improve postoperative analgesia after hip surgery and may be useful as a diagnostic block for various chronic pain conditions. The authors indicated that clinical trials are mandated. Limitations of this study include very small sample size, healthy subjects without back pain were utilized and there was no randomization to any other low back pain treatment for comparison other than placebo.⁹

References

1. Centers for Medicare & Medicaid Services (CMS). Medicare Coverage Database. National coverage determination (NCD) Search. Accessed at: http://www.cms.gov/medicare-coverage-database/
2. Iwamoto N, Isu T, Kim K et al. Treatment of low back pain elicited by superior cluneal nerve entrapment neuropathy after lumbar fusion surgery. Spine Surg Relat Res. 2017 Dec 20;1(3):152-157. 
3. Isu T, Kim K et al. Superior and Middle Cluneal Nerve Entrapment as a Cause of Low Back Pain. Neurospine. 2018 Mar;15(1):25-32. doi: 10.14245/ns.1836024.012. Epub 2018 Mar 28. 
4. Kim K, Isu T, Matsumoto J et al. Low back pain due to middle cluneal nerve entrapment neuropathy. Eur Spine J. 2018 Jul;27(Suppl 3):309-313. doi: 10.1007/s00586-017-5208-2. Epub 2017 Jul 5. 
5. Kim K, Isu T, Chiba Y, Iwamoto N et al. Treatment of low back pain in patients with vertebral compression fractures and superior cluneal nerve entrapment neuropathies. Surg Neurol Int. 2015;6(Suppl 24):S619-S621.
6. Kokubo R, Kim K, Isu T, Morimoto D et al. Superior cluneal nerve entrapment neuropathy and gluteus medius muscle pain: their effect on very old patients with low back pain. World Neurosurg. 2017;Feb;98:132-139.
7. Kuniya H, Aota Y, Kawai T et al. Prospective study of superior cluneal nerve disorder as a potential cause of low back pain and leg symptoms. J Orthop Surg Res. 2014 Dec 31;9:139.
8. Matsumoto J, Isu T, Kim K et al. Middle cluneal nerve entrapment mimics sacroiliac joint pain. Acta Neurochir (Wien). 2019 Apr;161(4):657-661. 
9. Nielsen TD, Moriggl B, Barckman J et al. Randomized trial of ultrasound-guided superior cluneal nerve block. Reg Anesth Pain Med. 2019;May 6.
10. Hayes a TractManager Company. Winifred Hayes Inc. Lansdale, PA: • Evidence Analysis Research Brief. Cluneal Nerve Block For Treatment of Low Back Pain. March, 2020.
11. AMR Peer Review Network: Policy reviewed by practicing board certified MD in Physical Med & Rehab, Pain Management. April, 2020

Coding Section 

Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each policy. They may not be all-inclusive.

This medical policy was developed through consideration of peer-reviewed medical literature generally recognized by the relevant medical community, U.S. FDA approval status, nationally accepted standards of medical practice and accepted standards of medical practice in this community, Blue Cross Blue Shield Association technology assessment program (TEC) and other nonaffiliated technology evaluation centers, reference to federal regulations, other plan medical policies, and accredited national guidelines.

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