<p>Chronic localized back pain due to entrapment of cutaneous branches of posterior rami of the thoracic nerves (POCNES): a case series on diagnosis and management</p>

Abstract

Introduction and aim Chronic back pain (CBP) may be caused by a variety of conditions including dysfunctional muscles, ligaments or intervertebral discs, improper movement of vertebral column joints, or nerve root compression. Recently, CBP was treated successfully in a patient having an entrapment of cutaneous branches of the posterior rami of the thoracic nerves, termed posterior cutaneous nerve entrapment syndrome (POCNES). Our aim is to describe clinical presentation, differential diagnosis, and management of patients with such a neuropathic pain syndrome. Methods This study analyzed prospectively obtained data from consecutive patients suspected of having POCNES, presenting to two Dutch hospitals between January 2013 and September 2016. Patients received a diagnostic 2–5 mL 1% lidocaine injection just below the thoracolumbar fascia. Pain was scored using a numerical rating scale (0 = no pain to 10 = worst possible pain). A >50% pain reduction was defined as success. A neurectomy was proposed if pain reduction was temporary or insufficient after one to three injections. Long-term treatment effect was determined using a verbal rating scale (VRS; 1 = very satisfied, no pain, to 5 = pain worse). Results Fourteen patients (12 women, median age 26, age range 18–73) were diagnosed with POCNES. Eighty-one percent (n=11) reported a >50% pain drop after injection (NRS pain scores of median 8.0 [IQR 7.0–8.0] to median 3.0 [IQR 1.5–3.5], P <0.001). In one patient, repeated injections were successful long-term (VRS score of 2). Two patients declined surgery, whereas the remaining eleven underwent a neurectomy that was successful in seven (64%). A 57% long-term efficacy (median 29 months follow-up, range 5–48, VRS score 1–2) was attained in the entire study population. Conclusion POCNES should be considered in the differential diagnosis of chronic localized back pain. A treatment regimen including injections and neurectomy of the specific cutaneous branch results in long-term pain relief in more than half of these patients.

A combination of three nerve entrapment syndromes, which was difficult to differentiate from a vertebral compression fracture

“…ACNES, POCNES and LACNES have a similar pathology, in that branches of the cutaneous nerve are entrapped by surrounding tissues, such as muscle, owing to several mechanisms [1] . These syndromes also have several common features: prevalence in women aged 20-50 years, rightsided dominance (except for POCNES), and frequent involvement of lower thoracic spine levels, including Th11 (Th7-12) [2][3][4] . Previous studies have reported that more than one of these syndromes can develop in the same patient [5] , so the occurrence of three cutaneous nerve entrapment syndromes in this patient is possible.…”

Efficacy of Erector Spinae Plane Block for Back Pain Referred from Visceral Pain in the Palliative Care Setting

“…In these 3 cases, bone metastasis, facet joint pain, and posterior cutaneous nerve entrapment syndrome (POCNES) were considered as differential diagnoses of back pain (16). Imaging studies did not indicate bone metastasis or facet joint abnormalities in any case.…”

“…Imaging studies did not indicate bone metastasis or facet joint abnormalities in any case. Facet joint pain was not indicated because patients did not report the pain, such as pain radiating into a somewhat larger area; furthermore, a specific point of maximum pain was absent or concerned multiple overlapping dermatomes (16). POCNES was not indicated because no skin somatosensory abnormalities were reported in any case.…”

Lateral Cutaneous Nerve Entrapment Syndrome (LACNES)

“…Lateral cutaneous nerve entrapment syndrome causes lateral thoracic pain and lateral abdominal pain, and POCNES causes dorsal pain (Figure 2). 2,3 Lateral cutaneous nerve entrapment syndrome is often idiopathic with rare triggers such as trauma, surgery, or obesity, which is also the case in ACNES. 2 The condition is characterized by the following three features: 1) a constant area of tenderness located in the flank, covering a fingertip-sized point of maximal pain in the midaxillary line; 2) a larger area of altered skin sensation such as hypoesthesia, hyperesthesia, or altered cool perception covering the pain point, but not necessarily corresponding to a specific complete dermatome; and 3) a positive pinch test.…”