腰椎椎間板ヘルニアに対する前方固定術後の再手術例の検討

The Reasons for Reoperation after Anterior Lumbar Interbody Fusion for Intervertebral Disc Herniation

　抄録：腰椎椎間板ヘルニアに対し前方固定術を施行した90例を対象とし，術後臨床成績と再手術の原因を調査した．治療成績はJOAスコアで，術前平均7.6点から術後1年13.6点，最終調査時12.9点と安定した長期成績を示していた．術後再手術症例は17例（19％）に認めた．L5/Sで総腸骨動静脈が側方に位置する症例において移植骨の脊柱管内打ち込み，椎間レベルより転位したヘルニアにおいてヘルニアの取り残しがそれぞれ1例発生し，術後後方手術を追加した．このような症例に対する前方固定術（腹膜外アプローチ）の適応については，十分な注意が必要である．採骨に伴う外側大腿皮神経障害1例に対し神経剝離術を施行した．有症性偽関節，遷延癒合が2例存在した．隣接椎間障害が術後1年から14年にわたって12例（13％）に発生し，術後再手術の大きな原因となっていた．1例に再前方固定術，11例に後方除圧術を施行した．

　There have been many follow-up studies on anterior lumbar interbody fusion (ALIF) for intervertebral disc herniation, and excellent clinical outcomes have been reported. However, some cases have required reoperation during the follow-up period.

　A total of 136 patients underwent ALIF for lumbar intervertebral disc herniation in our hospital. Of these, 90 patients, can be followed-up for 6 to 20 years (average 13 years). 68 were male and 22 were female and their average age at operation was 39 years (range, 14 to 68 years). The Japanese Orthopaedic Association Low Back Pain Score (JOA score without restriction of ADL, perfect score：15 points) was used to evaluate the outcome.

　The mean JOA score was 7.6 points before surgery, 13.6 points 1 year after surgery, and 12.9 points at final follow-up. Reoperation was necessary in 17 Cases (19％). Impaction of grafted bone in the spinal canal and remnants of a herniated mass was observed in one case each of L5/S1 intervertebral disc herniation,and a posterior decompression operation was performed to treat these cases. Neurolysis for a lateral femoral cutaneous nerve injury at the bone graft harvest site was required in 1 case. Symptomatic non-union or delayed union was observed in 2 cases. Symptomatic adjacent segment disease developed in 12 cases (13％). The disease-free survival rate of adjacent segment following ALIF was 93％ at 6 years, 88％ at 10 years, and 74％ at 15 years according to a Kaplan-Meier analysis.