In contrast to polyneuropathies where most or even all peripheral nerves are affected, mostly in a symmetric manner, damage to a peripheral nerve at one site causes focal neuropathies [
1]. The most frequent neuropathies of the lower extremity are peroneal neuropathy followed by sciatic neuropathy [
2]. Due to its long anatomic course, various sites of sciatic nerve injury are possible with the hip as the most common location of lesions [
2]. Sciatic neuropathy can be traumatic, often with more severe clinical presentation depending on the location and severity of injury to the nerve [
3]. Iatrogenic sciatic neuropathy due to surgery, most importantly hip replacement surgery, is the most frequent cause of non-traumatic perioperative sciatic neuropathy [
4]. In a study of 109 non-traumatic sciatic neuropathy patients, 39 had non-perioperative causes of sciatic neuropathy, most frequently compression (
n = 16), inflammation (
n = 8) and idiopathic (
n = 6). Other less frequent causes were weight loss, infection, radiation, piriformis entrapment, perineuroma and ischemia [
4]. In a study on 92 consecutive patients evaluated for sciatic neuropathy, nerve infarction was the third most important cause (10% of patients) after hip arthroplasty and acute external compression [
3]. Ischemic sciatic neuropathies have been described in the context of aneurysms with formation of arterial thrombosis on the basis of arteriosclerosis [
5], arterial thrombosis after acetabulum fracture and surgery with ilioinguinal approach [
6] or intra-operative arterial occlusion during total hip arthroplasty [
7]. McManis described six cases of sciatic neuropathy after cardiac surgery. Four of them underwent prolonged periods of intra-aortic balloon pump therapy with a catheter in the femoral artery ipsilateral to sciatic nerve lesion. The other two experienced an ipsilateral femoral artery occlusion [
8]. In another case report, ischemic neuropathy of the peroneal and tibial nerve as a rare complication of aorto-femoral bypass surgery has been described [
9].
Spontaneous arterial ischemia with secondary axonal nerve damage due to occlusive vascular disease had been first described under the term “ischemic neuritis” in 1949 [
10,
11]. Later the term ischemic monomelic neuropathy (IMN) was introduced by Wilburn et al. in 1983 [
12] and recently discussed in a report of three cases [
13]. Ischemic monomelic neuropathy has been originally described as a non-compressive occlusion of blood supply or steal phenomenon causing single or multiple axonal mononeuropathies in the distal limb, without necrosis of muscles or skin [
12]. Causes are typically thromboembolic diseases in cases without preceding vascular surgical procedures [
12]. The typical clinical presentation is acute onset of persisting deep, burning pain of a distal extremity, accompanied by paresthesia and numbness, with or without motor weakness [
12]. Classical features of limb ischemia such as intermittent ischemic claudication, paleness and swelling of the limb and clinical evidence of necrosis are typically absent and pulses may be palpable [
12]. Therefore, a significant and detrimental delay in diagnosis may occur with patients misdiagnosed with lumbar radiculopathy [
12] or even complex regional pain syndrome [
13].
We present two cases of ischemic sciatic neuropathy due to arterial thrombosis.