絞扼性腓骨神経障害の臨床像に関する検討

Clinical Feathers and Treatment of Peroneal Nerve Entrapment Neuropathy

Ⅰ．緒　　言

　腓骨神経障害は，下垂足を伴い，腓骨神経領域のしびれや感覚障害を呈するものとして知られているが，運動麻痺が軽度であっても，知覚障害を主として発症するものもある^7,15,18)．しかしその臨床像に関する報告は少なく，本邦で一般的に治療されているとは言いがたい．一方，間欠性跛行は腰部脊柱管狭窄症にみられる特徴的症候の1つとして知られているが，ときに腰椎病変が明らかでないものや，外科治療で腰椎病変を治療したにもかかわらず，間欠性跛行が改善しないものも経験する^{11,13-16,24,25,30,31)}．今回われわれは，当科で治療した腓骨神経障害の臨床像に着目し，特に間欠性跛行との関連について検討したため，報告する．

　OBJECTIVE:Peroneal nerve entrapment neuropathy（PEN）is generally known as a drop foot with sensory disturbance. However, some patients experience numbness and pain in the affected area without severe paresis due to PEN. We report the clinical features and our surgical results of PEN cases.

　METHODS:We encountered 17 cases of PEN. The patients were 7 females and 10 males and their ages ranged from 30 to 78 years（average 56.1 years). In these cases, conservative therapy was unsuccessful;therefore, we performed surgical treatment for PEN.

　RESULTS:Among the 17 cases, 4 were of bilateral and 13 were of unilateral PEN. There was no severe paresis, as in drop foot;however, mild paresis（4/5, manual muscle test, MMT）was noted in 15 cases. In all cases, intermittent claudication presented, which ranged from 10 to 800m（average 150m). In 13 cases, radiological abnormality of the lumbar region was noted and 8 cases had a history of lumbar surgery（they had failed back surgery syndrome). In all the cases, we performed neurolysis of the peroneal nerve under local anesthesia;there was no surgical complication. After the surgery, symptoms improved, and the numerical rating of the lower limb improved from 8.6/10 to 0.8/10. Intermittent claudication also improved in all of the cases.

　CONCLUSIONS:We successfully treated 17 cases of PEN, which had lower limb pain without severe paresis, as in drop foot. Our results indicate that PEN should be recognized as a cause of intermittent claudication. Neurolysis for PEN under local anesthesia is less invasive and is useful for the treatment of lower limb pain.