Table 1.

Summary of reports on the features and treatment of superior cluneal nerve entrapment

Study	Study summary
Strong and Davila (1952) [2]	The success rate was 80% in 39 operated patients with superior- or middle cluneal nerve entrapment (SCN-E, MCN-E); 57% of patients with SCN-E reported groin pain and/or leg symptoms.
Takayama and Utsumi (1961) [3]	Intractable low back pain (LBP) was attributable to SCN-E in 200 Japanese patients. The surgical outcomes were rated ‘good’ in 87% of operated patients.
Kuniya et al. (2013) [4]	An anatomical study of the SCN in 109 usable specimens revealed several anatomical variations in the run patterns of SCN branches.
Lu et al. (1998) [5]	A study was performed on the relationship between the SCN and the posterior iliac crest and thoracolumbar fascia in 15 cadavers. The osteofibrous tunnel was cited.
Maigne and Doursounian (1997) [6]	Among 1,800 patients with LBP, 29 (1.6%) presented with SCN-E. SCN block only was effective in 10 of these patients, the other 19 underwent surgery. After 3.2 years, the surgical treatment outcome was rated as excellent in 13- and as unsatisfactory in 6 patients.
Maigne et al. (1989) [7]	An anatomical study of 37 dissected SCNs. The osteofibrous tunnel was cited.
Konno et al. (2017) [8]	In 16 cadavers, the SCN originated at the T12 to L5 nerve root. These anatomical findings may explain why patients with SCN-E often suffer leg pain or tingling that mimics sciatica.
Tubbs et al. (2010) [9]	The relationship between the SCN and the MCN and the posterior superior iliac spine on 20 cadaveric sides was discussed.
Maigne and Maigne (1991) [10]	This anatomical study of 37 dissected SCNs examined the relationship between the SCN and clinical symptoms around the iliac crest.
Kuniya et al. (2014) [11]	A prospective study of 834 patients, 113 of whom (13.5%) suffered LBP due to SCN-E; 54 of these (49%) also manifested leg symptoms. SCN block therapy was often useful; 19 patients underwent SCN neurolysis. Complete or almost complete relief of leg symptoms was obtained in 5 of the operated patients.
Morimoto et al. (2013) [17]	A detailed description of a successful, less invasive surgical procedure to treat 55 sides with SCN-E by neurolysis under local anesthesia.
Ermis et al. (2011) [18]	The quality of life in individuals with LBP was examined. The study included 25 patients with SCN-E, 25 patients with lumbar disc herniation, and 25 healthy subjects. SCN-E was successfully treated by only SCN blocks. Patients with SCN-E scored lower on the mental health section of SF-36 than individuals with lumbar disc herniation. The physical health score and LBP indices were not significantly different.
Aly et al. (2001) [19]	Two female teenagers whose condition was diagnosed late. Both had engaged in vigorous sports activities; SCN block was effective in the abatement of their LBP.
Speed et al. (2011) [20]	A young professional cricketer with severe LBP due to SCN-E who responded to SCN neurolysis.
Berthelot et al. (1996) [21]	LBP due to SCN-E was successfully treated by SCN neurolysis in a 48-year-old woman with LBP.
Akbas et al. (2005) [22]	A 62-year-old male with SCN-E diagnosed 8 years after decubitus surgery. His LBP improved by only SCN block.
Talu et al. (2000) [23]	Successful treatment of a 55-year-old patient with acute unilateral intractable LBP by only SCN block.
Iwamoto et al. (2016) [24]	Severe LBP was alleviated in 8 Parkinson patients by SCN entrapment treatment; 4 patients each underwent SCN block only or SCN neurolysis. The Hoehn-Yahr classification improved in 7 of the 8 patients.
Morimoto et al. (2017) [25]	A study of the long-term surgical outcomes (41.3 months) in 79 sides with SCN-E. LBP associated with leg symptoms was reported by 60% of the patients. While all patients experienced symptom improvement, LBP due to SCN-E recurred on 10 sides (13%) and required additional treatment for SCN-E. At the last follow- up visit all patients reported significant improvement.
Trescot (2003) [26]	A review of the effectiveness of cryoanalgesia for interventional pain management. SCN-E was reported to mimic radiculopathy due to lumbar disorder.
Kim et al. (2017) [27]	LBP and leg pain in patients with paralumbar spine diseases including SCN-E entrapment, can be misdiagnosed as lumbar disc herniation. As treatment based on a misdiagnosis may result in failed back-surgery syndrome, SCN-E must be differentiated from lumbar disc herniation.
Chiba et al. (2015) [28]	In 5 patients with intermittent LBP due to SCN-E, SCN neurolysis was successful. SCN-E should not be over-looked as a causal factor in patients in whom walking elicits LBP.
Kim et al. (2013) [29]	Indocyanine green (ICG) video angiography was reported to be useful for SCN neurolysis. As the peripheral nerve is supplied from epineurial vessels around the nerve, ICG video angiography facilitated inspection of peripheral nerves such as the SCN, helped to identify the SCN, and could be used to confirm sufficient SCN-E decompression intraoperatively.
Kokubo et al. (2017) [30]	Seventeen consecutive elders with LBP and leg pain improved by SCN entrapment and gluteus medius muscle pain treatments. Even very old patients with symptoms due to SCN entrapment can be treated successfully by less-invasive surgery and local block.
Kim et al. (2015) [31]	Of 27 patients with LBP due to SCN-E elicited by vertebral compression fractures, 17 responded to SCN block only. The other 10 reported pain alleviation after SCN neurolysis.
Matsumoto et al. Forthcoming [32]	Residual symptoms were reported by 27% of patients who had undergone lumbar decompression surgery. They required additional treatments for para-lumbar- and peripheral nerve diseases including SCN-E.
Iwamoto et al. (2017) [33]	After lumbar fusion surgery, 8 patients reported LBP. SCN-E was treated by SCN neurolysis and their LBP improved significantly.
Yamauchi et al. Forthcoming [34]	Persistent or recurrent LBP and/or leg pain after lumbar discectomy were significantly improved in 13 patients by treating peripheral neuropathy including SCN-E.
Kim et al. Forthcoming [35]	SCN neurectomy was performed to treat 7 nerves in patients with intractable LBP. Their symptoms improved after surgery. A review of the pathologic features and the effectiveness of SCN neurectomy suggest that SCN neuropathy elicited LBP via nerve compression.