頚椎椎弓形成術後の軸性疼痛―前向き研究

Prospective Study to Locate the Cause of Axial Neck Pain after Laminoplasty

　頚椎椎弓形成術後に生じる軸性疼痛の原因を解明するため前向きに検討を行った．われわれは以前より蝶番側の深層伸筋を딵離しない術式を採用しているが，この術式を経年的にC3-7形成からC3-6形成へ，さらに左딵離から右딵離へと変更した．軸性疼痛はC3-7群30％，C3-6群7.5％とC3-6群で有意に少なかった．C3-6群のうち左딵離群と右딵離群を比べると，術後早期に一過性の軸性疼痛が筋딵離（開放）側に出現したがごく軽いものであった．以上より，軸性疼痛の発生にはC7への手術侵襲が強く関与しており，深層伸筋딵離の関与は少ないものと考えられた．

　Cervical laminoplasty is an excellent surgical procedure for the treatment of myelopathy secondary to multisegmental cord compression, although many patients experience its notorious postoperative complication：axial neck pain. To locate the cause of the axial pain, we prospectively allocated 91 myelopathy patients to undergo three different types of laminoplasty and investigated the incidence of axial pain in the left-opened C3-7 laminoplasty group (n＝37), left-opened C3-6 laminoplasty group (n＝31) and right-opened C3-6 laminoplasty group (n＝23). The paravertebral muscles on the hinged side are all preserved in our original open-door laminoplasty technique. Significant axial neck pain developed in 30％ of the patients after C3-7 laminoplasty, but the rate was only 7.5％ after the C3-6 procedure (p＝0.015). When we checked the slightest pain after the C3-6 procedure, it was predominantly on the side that was opened, although it dissolved spontaneously within a month. We concluded that there is little relationship between the paravertebral muscles and axial pain after laminoplasty, but that C7 is strongly associated with axial pain, and it should not be included in the procedure to prevent it.