Characteristics and clinical significance of spine-pelvic sagittal morphology of adolescent L5 spondylolisthesis

English Keywords:Adolescents lumbar spondylolisthesis  Spondylolysis  Dysplasia  Sagittal balance  Spino-pelvic parameters

English Abstract:

  【Abstract】 Objectives: To study the sagittal spinopelvic morphological characteristics of adolescent with L5 spondylolisthesis, and analyze the sagittal parameters and clinical significance of different types of spondylolisthesis. Methods: Retrospective analysis was performed on adolescent patients with L5 spondylolisthesis treated in our hospital from January 2010 to December 2019. Of all 36 patients with intact medical data, there were 18 males and 18 females with an average age of 14.1±2.5 years (10-18 years). According to Wiltse classification, the patients were divided into isthmic type (28 cases) and dysplasia type (8 cases). According to Meyerding classification, 32 cases were mild spondylolisthesis (29 cases were of grade Ⅰ and 3 cases were of grade Ⅱ) and 4 cases were severe spondylolisthesis (2 cases were of grade Ⅲ and 2 were of grade Ⅳ). The sagittal spinopelvic parameters were measured on the standing lateral full-length spine radiograph, among which were slip parameters including slip rate (SR) and slip angle (SA); sagittal parameters of the pelvis including pelvic incidence (PI), pelvic tilt (PT), lumbosacral angle (LSA), and the sacral table angle (STA); spinal sagittal parameters including thoracic kyphosis (TK), lumbar lordosis (LL) and sagittal vertical axis (SVA). The sagittal spinopelvic parameters of isthmic and dysplastic group as well as mild and severe group were compared. Results: SR=(13.7±8.1)%, PT=15.7±8.3°, LSA=105.9±11.8° and STA=102.8±6.5° in isthmic type; SR=(42.4±27.8)%, PT=34.2°±9.6°, LSA=78.7±11.2° and STA=76.4±9.5° in dysplastic type. The difference between the two groups was statistically significant(P<0.05). SR=(14.4±7.8)%, PT=18.1°±10.4°, LSA=102.1°±15.5° and STA=99.9°±10.8° in mild spondylolisthesis; SR=(65.0±19.6)%, PT=33.9°±11.1°, LSA=77.4°±6.7° and STA=77.7°±8.8° in severe spondylolisthesis. The difference between the two groups was statistically significant(P<0.05). SA=2.6°±13.1°, PI=54.6°±9.0°, TK=23.5°±15.5° and LL=-53.0°±18.3° in isthmic type; SA=11.2°±10.5°, PI=60.8°±14.5°, TK=21.5°±14.3° and LL=-45.3°±15.9° in dysplastic type; there was no statistical difference between the two groups(P>0.05)。SA=3.3°±12.6°, PI=55.3°±10.4°, TK=24.0°±13.1° and LL=-52.7°±17.4° in mild spondylolisthesis; SA=14.5°±12.8°, PI=61.0°±12.2°, TK=14.8°±3.7° and LL=-40.0°±20.0° in severe spondylolisthesis, with no statistical difference between the two groups(P>0.05). Conclusions: In L5 spondylolisthesis of adolescents, most of the dysplasia type is severe spondylolisthesis, while the isthmus type is mild spondylolisthesis. Severe spondylolisthesis of dysplasia is prone to sagittal imbalance and progress of spondylolisthesis. The sagittal plane of spine pelvis presents the forward sloping trunk, the sacrum is vertical and the pelvis is inclined backward.