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Léri’s sign is an equivalent of straight leg raise to detect irritation of L4 and L3 nerve root.
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In this test, the examiner lifts the patient’s leg while the knee is flexed.
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The analysis shows Leri’s sign was positive in 95% of the cases in operated patients before surgery.
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Our study shows the sensitivity of Leri’s sign 0.9333 and the specificity 0.7974.
Abstract
Although not as frequent as sciatica, cruralgia remains one of the most frequent reasons why people consult a neurosurgeon. It should be kept in mind, however, that every anterior leg pain is not cruralgia and thus several diagnoses must be discarded, such as of musculoskeletal diseases of hip, pelvis and femur. In the last years of the 19th century, André Léri, a French neurologist, described Leri’s sign as it is used widely even today in everyday clinical practice. We studied retrospectively files of those patients who were seen in Neurosurgery by the authors for L3 and L4 nerve root compression to evaluate the reliability and accuracy of this sign.
Between October 1998 and September 2017, 38,654 patients were examined in our department of Neurosurgery. Among them, 1698 patients presented pain as cruralgia and meralgia. In total, 1545 patients were included in the study. The data analysis showed that the sensitivity of LS was 0.9333 and the specificity 0.7974. The results of the study show a reliable diagnostic accuracy of Leri’s sign.
André Léri, a French neurologist, was born in 1875 in Paris. He was a student of Joseph Babinski, the famous French doctor. He was promoted to Professor in 1910 in the Faculty of Medicine of Paris. The total number of his academic treatises is 323. They address different diseases like tabes, syphilis, blindness and bone disorders. In particular, he discovered mesosomatic lipomatosis (Léri disease) [
He proposed a test to detect nerve root compression lesions for L4 and L3 nerve roots. It is called Léri’s sign in French medical terminology. It is also known as “Inverted Lasegue sign” in English medical terminology [
Léri’s sign(=LS) is an equivalent of straight leg raise (Laségue sign) to detect irritation of L4 and L3 nerve root. It is an inherent part of the spine clinical examination. The test is performed with the patient lying face down -prone position- on an examination table. The examiner lifts the patient’s leg while the knee is flexed (Fig. 1). This test causes a compression of nerve roots and triggers the patient’s usual radicular pain. As a reminder, the L4 nerve root supplies sensitivity innervation of the front of the thigh, the front of the leg and above the foot. The L3 nerve root supplies sensitivity innervation of the anteromedial surface of the thigh and the knee interne side. The L4 supplies gluteus medius and minimus, quadratus femoris and lumborum, tensor fasciae latae, obturator externus, inferior gemellus and tibialis anterior. The L3 supplies quadratus lumborum, obturator externus and iliopsoas muscles either directly or through nerves originating from L3.
Fig. 1Leri’s sign. Positive if it reproduces the usual pain along the same path.
We reviewed clinical records of patients who presented cruralgia – L4 nerve root radiculalgia – or meralgia – L3 nerve root radiculalgia – to assess the reliability of Leri’s sign in actual medical practice before and after surgical and conservative treatment.
2. Material and methods
Between October 1998 and September 2017, 38,654 patients were examined in our departments of Neurosurgery. Among them, 1698 patients presented pain as cruralgia and meralgia. Patient were included in the study only if the pain trajectory was always the same and followed L3 and L4 nerve roots (the front of the thigh, the front of the leg and above the foot for L4 and the anteromedial surface of thigh and the knee interne side for L3). Patients with various aspects of symptoms and various pains or with pain of hip or pelvis were excluded. Patients who had constant pain (153P.) without imaging evidence -disk herniation, foraminal stenosis or tumour were excluded from the study. Simultaneously, patients who had mixed radicular compression L3 and L4 were excluded. We detected three main causes for nerve root compression: disk herniation, foraminale stenosis in relation to degenerative diseases and tumours. In total, 1545 patients were included in the study. Among them, 168 patients were treated only by conservative management (medicine, physiotherapy, rest). Of these patients, 962 had surgery and 414 had epidural or periradicular injection. The operated patients had been seen after 4 weeks and 8 weeks for the first two postoperative controls. The others had been seen on average after 2, 4 and 8 weeks. During every control, all the patients had a clinical examination including Leri’s sign. Table 1, Table 2 demonstrate patients’ characteristics with L3 and L4 nerve root pain.
Table 1Patients’ characteristics with L4 nerve root pain.
Patients
1299
Operated
Infiltrated
TCM
DH
437
203
178
56
DFS
811
505
207
99
T
51
51
0
0
Abbreviation: DH = Disk herniation; DFS = Degenerative foraminal stenosis; T = Tumour; TCM = Treated by conservative management.
The analysis of the collected data shows that Leri’s sign was positive in 95% (914) of the cases in operated patients before surgery.
Four weeks after surgery, 901 patients (93.66%) became pain free. However, 61 patients (6.34%) remained painful after that time. Eleven painful patients (1.20%) were still Leri’s sign positive. However, 2 pain-free patients had LS positive. Eight weeks after surgery, 11 patients (1.14%) remained painful and 9 (0.98%) patients were LS positive. The outcome is supportive of strong correlation between nerve root compression and an LS positive.
Among 414 patients treated by infiltration, 75 patients (18.12%) still had pain 4 weeks after surgery. Eight weeks after surgery, 69 patients (16.67%) were painful. Among patients treated by infiltration, 389 patients (93.96%) had LS positive before treatment. This number had decreased to 48 patients (12%) after 4 weeks and to 41 (10.54%) after 8 weeks. While the number of pain-free patients decreased considerably, the number of LS positive patients remained high. This reflects the persistence of nerve root compression in more than 10% of patients. As regards the conservatively treated patients, they were 169 during the initial stages of management. However, 99 patients (58.93%) after 4 weeks and 76 patients (45.24%) after 8 weeks remained painful. Among this population, 139 patients (82.74%) were LS positive at the beginning of the management. Four weeks later, 89 patients (64.03%) were LS positive and 8 weeks later, 73 patients (52.52%) were LS positive.
To provide quantitative analyses of sensitivity and specificity of Leri’s sign, we compared simultaneously the number of false negatives and positives and true negative and positives [
]. As noted above, in 1545 painful patients, we found imaging findings of nerve root compression. We found that 103 patients had pain and nerve root compression on imaging, but LS was negative (false negatives). The sensitivity of LS is 0.9333.
The 153 patients – excluded of the study – had pain imitating nerve root compression without imaging findings of compression. Among them, 122 patients were LS negative (true negative) and 32 patients were LS positive (false positive). The specificity is, therefore 0.7974.
4. Conclusion
The study reflects everyday clinical practice of four physicians (neurosurgeons and neurologist). The results of the study show a reliable diagnostic accuracy of Leri’s sign, given the significant number of patients and given the number of physicians participating in the study, working in different institutions.
The authors declare that they have no conflict of interest.
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