腰椎椎間孔部病変の手術方法

Surgical Method for Lumbar Foraminal Stenosis

Ⅰ．はじめに

　椎間孔部狭窄の概念は，1976年にArnoldi ¹⁾らが初めて外側型狭窄として報告した．また，1981年にBurton ³⁾らは，この病態はfailed back surgeryの約60％を占め，術後成績不良の要因になると報告した．近年，MRI，CTなどの画像診断の普及によりさまざまな診断方法が確立したが，治療方法，特に手術方法に関しては，罹患椎体固定術⁵⁾か，単独除圧術⁹⁾のみかについてのコンセンサスはない．われわれは，久野木の分類⁸⁾に従って，椎間孔部狭窄と診断した症例について，当科での手術方法（顕微鏡的単独除圧術）を示すとともに，術後臨床評価についても報告する．

　Objective: There are mainly two surgical methods for lumbar foraminal stenosis,simple decompression of the extra-foraminal portion or decompression with fixation surgery. However the indication of either method is controversial. The aim of this study is to show our surgical method and results.

　Method: In six cases diagnosed as lumbar foraminal stenosis with or without far lateral disc herniation by X-ray, CTscan, MRI and nerve conduction velocity, decompression surgery was performed by our paramedian method (Wiltse approach). The apex and lateral portion of the superior articular facet (one third to one fourth) and the transforaminal ligament without fixation for lumbar foraminal stenosis. All patients were followed up for more than 10 months after the surgery. Japanese Orthopaedic Association (JOA) score and Visual Analogue Scale (VAS) were assessed before surgery and more than 10 months after the surgery. Postoperative radiological assessments were examined by neutral, flexion and extension X-ray.

　Result: Foraminal stenosis was successfully decompressed in all cases. The postoperative JOA score and VAS were significantly improved in comparison to the preoperative score (Recovery Rate ware of 74.9% and 85.8%). There was no recurrence of symptoms or necessity for secondary surgery. The radiological evaluation did not indicate significant instability or decrease in the disc height.

　Conclusion: Our surgical method,removing the apex and lateral part of the superior articular process and transforaminal ligament without fusion led to a good outcome and recurrence 10 months after the surgery had not occurred.