The Effects Of Modified PLIF On Postoperative Adjacent Segment Degeneration And Its Clinical Efficacy

【Background】Posterior lumbar interbody fusion (PLIF) still remains one of the most common surgicalapproaches in the treatment of lumbar degenerative diseases. Compared with the othermethods, this surgical approach could expose visual operative field fully and relieve theentrapment of the nerve root completely. Meanwhile, it could also provide solid internalfixation and promote the recovery of spinal stability. However, some of the side effects ofthis operation also attracts great attention of the researchers, and adjacent segmentdegeneration is the problem that need to be resolved urgently. The pathogenesis of ASDand its risk factors remain ambiguous, and it has been recently accepted that posteriorligamentous complex (PLC) injury might play a crucial role in ASD. Therefore, it ischallenging to search for the approach that could preserve the integrity of PLC withoutaffecting the exposure of operative vision and decompressive effects. In order to solve thisproblems, we have carried out modified PLIF with reservation of PLC ever since2010.Compared with the traditional PLIF, we only cut down the partial spinous to keep theintegrity of PLC of adjacent vertebral in this modified approach. However, it remainsunclear whether modified PLIF on ASD and its clinical efficacy. 【Objectives】1. To compare the differences of clinical therapeutic effects and morbidity of ASDbetween modified and traditional PLIF;2. To explore the significance of PLC inprevention of postoperative ASD.【Methods】158patients from Mar2010to October2012, were included in this study.78patientswere treated with traditional PLIF (40males,38females, average age52.3±12.6years) and80patients received modified PLIF(42males,38females, average age51.1±12.6years).The patients were followed up for an average of28months (12-36months). X-rayexamination was used to evaluate the occurrence of postoperative ASD and the clinicaleffect was evaluated by visual analogue scores (VAS) and Oswestry disability index (ODI).【Results】1. There was no significant difference in age, gender, clinical diagnosis or the segmentbetween the two groups(P＞0.05). The VAS and ODI scores in the last follow-upinterview were both significantly reduced than that before the operation(P＜0.05), but nosignificant difference was observed between two groups (P＞0.05). However, there were32cases exhibiting radiographic degeneration (degeneration rate41.0%) and symptomaticdegeneration in the traditional group, while only9(11.3%) and3(3.8%) cases were foundto be the same, respectively. There were no obvious correlation between radiographicASD and the clinical effects (P＞0.05), and only symptomatic ASD was associated withthe clinical outcomes (P＜0.05).2. ASD was not associated with age, gender and the height of the intervertebral disc,and the damage to the PLC during the surgery was one of the direct causes of ASD.【Conclusions】The modified PLIF could reduce the morbidity of ASD. ASD was not associated withage, gender and the height of the intervertebral disc during the surgery, but the correlationbetween the damage to adjacent vertebral PLC and ASD was found. Therefore, we speculated that the reservation of adjacent segment PLC could prevent the postoperativeASD.