Correlative Factors Analysis For Degeneration Of Adjacent Segments After Lumbar Spinal

Objective: To Analyze and explore factors causing adjacent segmental degenerations after lumbar fusion surgery. Methods: A retrospective analysis was applied among 256 cases of lumbar stenosis treated with lumbar posterior decompression, pedicle screw fixation and fusion in orthopedic department of XinJiang Medical University First Hospital from May 2010 to January 2013.These cases included 136 males and 120 females with ages ranging from 27 to 81 and an average of 56. All of them were followed up by a 1- to-5year clinic investigation, with an average of 3.0 years. Measurements included lumbar lordosis(LL), sacral slope(SS), pelvic incidence(PI) in pre-operation。Record gender, age, fusion segment. Adjacent segment imaging degeneration is defined by adjacent segmental slip 3mm or more on standing X-ray post-operative 24-month. All patients were categorized into degenerative group(Group A) and non-degenerative group(Group B). The comparative results between two groups was analyzed by t-test and χ2 –test. Affecting factors of adjacent segment imaging degeneration were analyzed using logistic regession. Results: There are 30 cases in Group A and 226 cases in Group B. All of ASD appears at proximal adjacent segments. Results of two groups for preoperative were as follows: LL group A28.9±11.5°, group B31.4±11.2°;SS group A 30.9±12.2°, group B 36.5±13.3°;(P<0.05). PI in group A 41.9°±9.6° was significantly lower than in group B 49.8°±9.7°(P<0.05). Gender, age, bone mineral density, number of fusion segments and DA were not the relative factors(P>0.05). Logistic regression analysis showed that PI was significantly associated with ASD. Conclusions: The PI and LL value are critical factors in evaluating the compensating capability of global equilibrium after lumbar fusion surgery and also a direct reason causing post-operative ASD.Age and Gender are both factors causing ASD.