Lumbar radiculopathy, characterized by signs and symptoms stemming from lumbar root dysfunction, often occurs concurrently with peripheral nerve entrapment, a condition known as double crush syndrome (DCS). Originally described by Upton and McComas in 1973, DCS indicates that a proximal lesion on a peripheral nerve can increase the risk for additional distal injuries, potentially leading to compounded nerve dysfunction [1,2]. Research on DCS affecting the lower limbs correlates lumbosacral radiculopathy with conditions such as tarsal tunnel syndrome and peroneal nerve (PN) entrapment, supported by clinical case studies or statistical evidence [3-5].

The effectiveness of Korean medicine therapies, including pharmacopuncture, in treating patients with lumbar disc herniation and various entrapment neuropathies, is being actively investigated and applied clinically [6,7]. Recently, ultrasound-guided pharmacopuncture has been actively used in clinical practice, which enhances therapeutic effects by precisely delivering medications to the targeted lesions [8,9]. This study provides a retrospective analysis of cases where patients with L5 nerve root compression also suffered from PN entrapment and discusses the treatment outcomes of such Korean medicine interventions.

1. Diagnosis

Three patients were diagnosed with lumbar stenosis at the L5 nerve root (Figs. 1–3). Clinical exams confirmed concurrent PN entrapment, showing progressive calf and foot paresthesia and hardening of the soft tissues on the bifurcation of the common PN. Symptoms included burning pain, motor weakness, and positive Tinel’s sign when pressing on the tender nerve area [10].

Figure 1. Magnetic resonance imaging on June 17, 2022. Mild foraminal stenosis, depicted on T2-weighted sagittal (A) and axial (B) images of a 70-year-old female. The L5/S1 foraminal stenosis results from facet arthrosis and a herniated disc, as indicated by the white arrows.

Figure 2. Magnetic resonance imaging on July 19, 2022. Severe right foraminal stenosis at L5/S1, depicted on T2-weighted sagittal (A) with axial (C) and T1-weighted sagittal (B) images of a 67-year-old male. The L5 nerve root is compressed in the foramen due to upward disc migration, shown in image (A, B) with a white arrow.

Figure 3. Magnetic resonance imaging on November 30, 2022. Severe right foraminal stenosis at L5/S1 shown on T2-weighted sagittal and axial images in a 59-year-old female. The L5 nerve root is severely compressed in the foramen by facet arthrosis shown in image (A, C, white arrow) and upward disc migration, indicated in image (B, C, yellow arrow).

2. Treatment

1) Ultrasound-guided pharmacopuncture

After admission, Shinbaro 2 pharmacopuncture (Jaseng Hospital of Korean Medicine), at a dosage of 4 mL (S4), was administered at the site near the L5 nerve root under ultrasound guidance. The patient was placed in a supine position, with a single ultrasound frame capturing the spinous processes, facet joints, and transverse processes. By shifting the probe caudally, the transverse processes were obscured, revealing the hypoechoic round-shaped cross-section of the nerve root above the vertebral body. S4 with 26-gauge × 60-mm needle attached to a disposable 5 mL syringe was injected at an oblique angle around the L5 nerve root (Fig. 4).

Figure 4. Sonogram of the L5 nerve root. D, disc; FJ, facet joint; L, lamina; N, needle; S, sacrum.

If improvement in lumbar-origin pain was noticed, the treatment was modified to Shinbaro 2 pharmacopuncture 2 mL (S2) administered near the corresponding PN area under ultrasound guidance, in a phase termed 'intervention changed (IC)'. Using an ultrasound probe along the transverse axis of both the deep and superficial PNs (Fig. 5), a 13-gauge, 38-mm needle with a disposable 3-mL syringe was used around the deep and superficial PNs (Tables 1, 2).

Figure 5. Sonogram of the peroneal nerve. AIMS, anterior intermuscular septum; DPN, deep peroneal nerve; EDL, extensor digitorum longus; F, fibula head; PL, peroneus longus; SPN, superficial peroneal nerve.

Table 1 . Ultrasound-guided pharmacopuncture treatment.

Patient no.	Duration (d)
	Total admission	S4*	S2†
1	26	14	4
2	30	15	5
3	33	17	5

*Shinbaro 2 pharmacopuncture at a dosage of 4 mL given near the L5 nerve root, ^†Shinbaro 2 pharmacopuncture at a dosage of 2 mL given near the peroneal nerve..

Table 2 . Ingredients of the pharmacopuncture solution.

Prescription	Components	Proportions (g/mL)
JS3-SBO Shinbaro 2	Paeoniae lactiflora	0.0027
	Ostericum koreanum Kitagawa	0.0013
	Aralia continentalis	0.0013
	Eucommiae Cortex	0.0013
	Radix Achyranthis	0.0013
	Rhizoma Cibotii	0.0013
	Radix Ledebouriellae	0.0013
	Cortex Acanthopanacis	0.0013
	Scolopendra subspinipes mutilans	0.0013

2) General pharmacopuncture

Ashi points mainly around the muscles showing tension, such as the erector spinae and tibialis anterior muscles, and L5/S1 EX-B2 were selected. For each acupoint, 1 mL of Shinbaro 2 pharmacopuncture solution was injected once a day using a 29-gauge × 13-mm insulin syringe.

3) Acupuncture

Acupuncture was performed twice daily using standardized needles (0.25 × 40 mm; Dong Bang Medical) for 10 minutes with infrared therapy. BL24, BL25, BL26, BL56, BL57, BL58, GB34, GB35, and GB36 acupoints were mainly selected, and the typical depth of the needle insertion was 20–30 mm. Above the acupoints, electroacupuncture at a frequency of 2 Hz was performed concurrently with the acupuncture.

4) Herbal medicine

During the hospitalization, Chungpajeon-H was administered three times daily (Table 3).

Table 3 . Ingredients of the herbal medicine.

Prescription	Components (g/pouch)	Administered	Daily dose
Chungpajeon-H	Acanthopanacis Cortex (5.000)	During each admission period	3 times/d
	Eucommiae Cortex (5.000)
	Ledebouriellae Radix (5.000)
	Achyranthis Radix (5.000)
	Cibotii Rhizoma (5.000)
	Atractylodis Rhizoma (2.500)
	Amomi Semen (2.500)
	Geranium thunbergii (2.500)
	Zingiberis rhizoma (1.250)
	Ledebouriellae Radix (0.250)
	Glycyrrhiza uralensis (1.667)
	Lasiosphaera seu Calvatia (7.500)

3. Evaluation

1) Patient-reported scales

The patient’s subjective score of overall pain was measured using a patient-reported numerical rating scale (NRS) that ranges from 0 (minimal) to 10 (worst). The functionality of the L-spine was evaluated using the Oswestry disability index (ODI) on a scale from 0 (minimal pain) to 100 (worst pain) points. The patient’s quality of life was assessed using the EuroQoL 5-Dimension (EQ-5D) questionnaire (EuroQoL Research Foundation), which was scored across five dimensions, with the best and worst scores being 1 and 0 points, respectively.

2) Motor and sensory tests

The patient underwent manual muscle testing to assess muscle strength and function, with grades ranging from 0 to 5. These grades are based on resistance, gravity, and joint motion and reflect a spectrum of functionality from 0% to 100%. Initially, sensory abnormalities in all patients were uniformly rated at 100 to denote maximum severity, whereas normal sensation received a grade of 0.

4. Case 1

1) Patient

The patient was a 70-year-old female patient admitted from July 5, 2022, to July 30, 2022.

2) Chief complaint

The chief complaint was low back pain with left lateral leg pain and numbness. She also suffered from paresthesia in the entire left foot, particularly concentrated on the foot dorsum, along with the left lateral calf.

3) Onset

Onset: May 30, 2022.

4) Past illness

Lumbar herniated intervertebral disc (HIVD) operation (June 15, 2016).

5) Present illness

On May 30, 2022, the patient was offered reoperation but chose injection and oral medications over 1 month in the rehabilitation medical hospital. Consequently, she was admitted to the hospital on July 5, 2022.

5. Case 2

1) Patient

The patient was a 67-year-old male patient admitted from July 18, 2022, to August 6, 2022.

2) Chief complaint

The chief complaint was low back pain with left lateral leg pain. He also suffered from left first-toe motor weakness and paresthesia at the left instep.

3) Onset

Onset: July 01, 2022.

4) Past illness

Lumbar HIVD (June 15, 2012).

5) Present illness

On July 1, 2022, the patient was diagnosed with lumbar stenosis and initiated medication for approximately 2 weeks. Consequently, he was admitted to the hospital on July 18, 2022.

6. Case 3

1) Patient

The patient was a 59-year-old female patient admitted from January 9, 2023, to February 10, 2023.

2) Chief complaint

The chief complaint was low back pain with right lateral leg pain and numbness. She also suffered from right ankle dorsiflexion motor weakness with paresthesia along the lateral calf and instep.

3) Onset

Onset: November 14, 2021.

4) Past illness

Lumbar HIVD operations on June 15, 2014; June 18, 2015; April 15, 2021; and October 14, 2021.

5) Present illness

On November 14, 2021, she began medication treatment with injections for approximately 1 year and offered reoperation on November 31, 2022. Consequently, she was admitted to the hospital on January 9, 2023.

7. Response to treatment

All assessment measures improved at discharge. In the IC stage, lower back pain resolved in case 1, and NRS scores significantly decreased in cases 2 and 3, but sensory abnormalities showed modest improvements of 40%, 50%, and 70%. Despite decreases in NRS and ODI scores, muscle weaknesses in cases 2 and 3 persisted until peripheral nerve entrapment-focused interventions, which led to notable improvements in muscle strength and sensory symptoms (Fig. 6, Table 4).

Figure 6. Changes in the NRS score. NRS, numerical rating scale.

Table 4 . Changes in ODI, EQ-5D, paresthesia, and motor weakness.

	Case 1				Case 2				Case 3
	Adm	IC	D/C		Adm	IC	D/C		Adm	IC	D/C
ODI	38	22.22	11.11		72	44	32		55.56	46.67	46.67
EQ-5D	0.473	0.837	0.854		0.377	0.722	0.856		0.677	0.677	0.72
Paresthesia	100	40	10		100	70	30		100	50	20
Motor (%)	100	100	100		50	80	90		80	80	90

ODI, Oswestry disability index; EQ-5D, EurQoL 5-Dimension; Adm, admission; IC, intervention changed; D/C, discharge..

This paper presents a retrospective case study of three ptients who exhibited improvements in NRS, ODI, sensory tests, motor grades, and EQ-5D scores at discharge. In all three cases, interventions were modified when the lumbar-origin pain significantly decreased, subsequently hastening the amelioration of motor weakness and sensory abnormalities.

Shibuya et al. [11] noted that when a single nerve fiber undergoes focal compression, it becomes susceptible to damage at a distal compression site along the same nerve fiber. This vulnerability is attributed to the disrupted axonoplasmic flow at the proximal compression site, leading to the introduction of the DCS to explain this phenomenon. Although short-duration experiments do not cause permanent nerve degeneration, prolonged compression can initiate Wallerian degeneration in the impacted nerve [12].

According to the DCS theory, the pathway of the PN corresponds to the dermatome associated with L5 radiculopathy, implying a linear relationship between focal compression of the L5 nerve root and effects on the common fibular nerve. Acupuncture and pharmacopuncture are believed to effectively alleviate pain by mechanisms that include relieving nerve entrapment and restoring the disrupted homeostasis of tissues and nerves [13,14]. Previous studies have reported that Shinbaro 2 pharmacopuncture alleviates inflammation through various mechanisms, including the reduction of serum prostaglandin E2, interleukin-1β, inducible nitric oxide synthase, cyclooxygenase-2, and tumor necrosis factor-α, as well as increasing pain thresholds in the peripheral system [15,16].

To date, DCS has been considered when the patient’s condition does not improve after alleviating compression at one site due to ongoing compression at another site along the PN [4]. For this reason, cases of sequential surgeries involving the spine and PNs have been reported [3,4]. However, surgery may not always be the best treatment option, particularly when it does not strictly meet the surgical indications. In this study, less invasive approach is notable as it marks the initial application of Korean medicine treatments integrating acupoints with neuroanatomical knowledge in light of DCS.

If muscle weakness and paresthesia do not improve after prolonged lumbar nerve compression, peripheral nerve damage might also be involved. Therefore, focusing treatment solely on the central nerve site may not completely ameliorate the residual abnormalities. Clinicians must be adept at discerning subtle distinctions and possess a deep understanding of differentiating between symptoms of single compression and DCS in clinical practice.

Conceptualization: MIJ. Data curation: MIJ, GTP, HIJ, CJK. Formal analysis: MIJ, HSP. Resources: GTP, HIJ. Supervision: MIJ. Visualization: CJK, SMY. Writing – original draft: MIJ. Writing – review & editing: MIJ.

The authors have no conflicts of interest to declare.

None.

The patients’ medical records and personal information were obtained from the Jaseng Hospital of Korean Medicine Institutional Review Board (IRB no. JASENG 2024-07-027).