Postoperative Loss of Disc Height in Instrumented Posterior Lumbar Interbody Fusion Using Keystone Bone Grafts

骨移植後方腰椎椎體間融合術術後椎間高度塌陷之探討

楊曙華(Shu-Hua Yang)

《Formosan Journal of Surgery》 40卷1期 (2007/02) Pp. 1-8

https://doi.org/10.29833/FJS.200702.0001

摘要

於後方腰椎椎體間融合(Posterior Lumbar Interbody Fusion, PLIF)手術中植入椎籠之理論基礎在增進補骨融合率及避免術後椎間盤高度的喪失，但術後椎間盤高度喪失之發生率及其臨床意義至今仍不清楚。本文研究目的在了解未植入椎籠之PLIF手術後，椎間盤高度塌陷的發生率及其對臨床症狀的影響。
自1999年7月至2002年8月間共有20位病患接受PLIF手術治療，術前診斷包括有11例退化性腰椎滑脫症、5例椎弓缺損性滑脫症及4例接受再次手術之患者。於PLIF手術中，椎間盤前半是以碎骨片填滿，之後再植入一公分立方的樞石狀植骨。手術後定期以X光檢查評估補骨融合狀況，手術逾24個月後進行病人臨床反應之評估。
以本文PLIF手術方法治療之融合率及病人臨床反應與文獻中其他近似方法相當。三例病患於補骨成功融合時發生超過2毫米以上的椎間盤高度塌陷，另有一例發生補骨融合失敗現象。術後椎間盤高度塌陷並未伴隨因椎孔狹窄引發之神經根病變，亦未與不理想之臨床治療效果相關。導致術後椎間盤高度塌陷之可能因素包括術前病人身體前傾時於手術部位有局部後突之現象，以及經椎莖植入之鋼釘侵入至椎間盤，二者均會影響手術中椎間盤部位填入碎骨片之緊實度，因而使位於前方之補骨穩定度不足，導致隨後的椎間盤高度塌陷。除此之外PLIF術後椎間盤高度塌陷之現象並未發現與其他因素具有相關性。
於PLIF手術中即使未植入椎籠，其術後椎間盤高度喪失之發生僅與少數特定危險因子有關，並且術後椎間盤高度喪失之現象並不會導致不理想之治療結果。

並列摘要

Objective: Rationales of using interbody fusion cages in posterior lumbar interbody fusion (PLIF) are enhancement of the fusion rate and prevention of postoperative disc height loss. However, the prevalence of postoperative disc height loss and its influences on clinical outcomes have not been clearly understood. The objective of this study was to clarify and the incidence and clinical consequences of postoperative disc height loss in instrumented PLIF with keystone grafts and packed bone chips but without an interbody fusion cage.
Methods: From July 1999 to August 2002, 20 patients who underwent at a total of 23 levels of PLIF by a single surgeon were evaluated. Preoperative diagnosis included degenerative spondylolisthesis in 11 patients, isthmic spondylolisthesis in 5 patients and failed back surgery syndrome in 4 patients. During surgery, the anterior half or two-thirds of the disc space was first filled and packed with bone chips, and then cubic keystone grafts approximately 1cm^3 in size were tamped into the disc space. Fusion status was assessed according to sequential postoperative radiographs, and clinical outcomes were evaluated at least 24 months after surgery.
Results: The fusion rate and clinical outcome in this study were comparable with those in the literature. Collapsed fusion with disc height loss of more than 2mm was observed in 3 levels and pseudarthrosis developed in one level. Postoperative loss of disc height was not associated with occurrence of radiculopathy secondary to foraminal narrowing and was not associated with unsatisfactory clinical outcomes. Factors associated with postoperative loss of disc height included focal kyphosis at preoperative flexion radiographs and invasion of transpedicular screws into the disc space. Both situations may jeopardize initial solid packing of bone chips, may lead to inadequate stability of the anterior bone graft, and then predispose to subsequent loss of disc height. No other radiographic or demographic factors were found to be contributive.
Conclusion: Postoperative loss of disc height developed only in the presence of certain risk factors when single-stage instrumented circumferential fusion was performed without using interbody fusion cage and would not lead to unsatisfactory clinical outcomes.

並列關鍵字

loss of disc height ； spinal instrumentation ； posterolateral lumbar interbody fusion PLIF ； keystone bone grafts