Lateral Cutaneous Nerve Entrapment Syndrome (LACNES): A previously unrecognized cause of intractable flank pain.

BACKGROUND AND AIMS: Chronic abdominal pain may occasionally be due to terminal endings of intercostal nerves (ACNES, abdominal cutaneous nerve entrapment syndrome) that are entrapped in the abdominal wall. Spontaneous neuropathic flank pain may also be caused by involvement of branches of these intercostal nerves. Aim is to describe a series of patients with flank pain due to nerve entrapment and to increase awareness for an unknown condition coined Lateral Cutaneous Nerve Entrapment Syndrome (LACNES). METHODS: Patients possibly having LACNES (constant area of flank tenderness, small point of maximal pain with neuropathic characteristics, locoregional altered skin sensation) presenting between January 2007 and May 2016 received a diagnostic 5-10mL 1% lidocaine injection. Pain levels were recorded using a numerical rating scale (0, no pain to 10, worst possible). A >50% pain reduction was defined as success. Long term effect of injections and alternative therapies were determined using a satisfaction scale (1, very satisfied, no pain - 5, pain worse). RESULTS: 30 patients (21 women, median age 52, range 13-78) were diagnosed with LACNES. Pain following one injection dropped from 6.9±1.4 to 2.4±1.9 (mean, p<0.001) leading to an 83% immediate success rate. Repeated injection therapy was successful in 16 (pain free n=7, pain acceptable, n=9; median 42 months follow-up). The remaining 14 patients received (minimally invasive) surgery (n=5) or other treatments (medication, manual therapy or pulsed radiofrequency, n=9). Overall treatment satisfaction (scale 1 or 2) was attained in 79%. CONCLUSIONS AND IMPLICATIONS: LACNES should be considered in patients with chronic flank pain. Injection therapy is long term effective in more than half of the population.

Renal colic in adults: NSAIDs and morphine are effective for pain relief.

(1) Renal colic is an acute syndrome involving unilateral flank pain, linked to an obstruction in the upper urinary tract. The pain is often intense. After having considered other diagnoses and checked for signs of complication (fever, oligoanuria), the first step is to control the pain; (2) Which non-invasive treatments have a positive risk-benefit balance in relieving this type of pain? To answer this question, we reviewed the available evidence, based on the standard Prescrire methodology; (3) According to a meta-analysis of 20 trials, nonsteroidal antiinflammatory drugs (NSAIDs) and strong opioid analgesics have comparable efficacy. The most widely studied NSAID is diclofenac, given intramuscularly at a dose of 50 mg or 75 mg. Pethidine is the best-assessed strong opioid, given intramuscularly at a dose of 50 mg to 100 mg, which corresponds to about 5 mg to 10 mg of morphine. Morphine is given intravenously; subcutaneous administration is an alternative although it has not been evaluated in renal colic; (4) In clinical trials, NSAIDs were associated with fewer adverse effects than opioids, which cause vomiting in about 20% of patients (versus about 6% with an NSAID); (5) NSAIDs expose patients to a risk of functional renal impairment, especially in patients with heart failure, renal artery stenosis, dehydration, renal impairment or ongoing treatment with a nephrotoxic drug, and the very elderly. NSAIDs should never be used during pregnancy; (6) According to one trial in 130 patients, the analgesic effect of the morphine and NSAID combination was greater than either agent used alone, in about 10% of patients; (7) Paracetamol has not been evaluated in comparative trials of renal colic, even for moderate pain; (8) Scopolamine is the only antispasmodic to have been evaluated in a comparative trial. Adding scopolamine to morphine did not seem to provide additional efficacy; (9) Other drugs, which have not been adequately tested as of early 2009, have no documented benefit in the treatment of the pain associated with renal colic; tamsulosin, nifedipine, desmopressin; (10) Among the non-drug measures tested, local active warming, taking care to avoid burns, was effective against pain according to one trial; pain was reduced by at least 50% using a device delivering 42 degrees C to the abdomen or lower back; (11) In pregnant women, morphine carries a lower risk of adverse effects than NSAIDs; (12) In practice, the treatment of renal colic is mainly based on taking an NSAID, or morphine when the NSAID does not adequately control the pain or when it is better to avoid using NSAIDs.