Objective To review the process of radiographic measurements of sagittal balance and offer reference for the clinical practice. Methods The related literature of spino-pelvic sagittal parameters and their clinical application was reviewed and analyzed from the aspects such as the clinical application, the advantages and disadvantages, and how to use them effectively. Results All parameters have their advantages and disadvantages, and they are influenced by age and race. Sagittal vertical axis can only reflect the global balance, and T1 pelvic angle which accounts for both spinal inclination and pelvic tilt can’t be controlled in the surgery. The correction goal for western people may be not suitable for Chinese. Conclusion The parameters should be used wisely when evaluating the sagittal balance, the global balance and local balance should be considered together and the different groups of people need different correction goals.
Objective To review the research progress of upper instrumented vertebra (UIV) selection strategy for long-segment fixation (LSF) in adult degenerative scoliosis (ADS). Methods The relevant domestic and foreign literature in recent years was reviewed, and the selection strategy of sagittal and coronal UIV for LSF in ADS patients, the relationship between UIV selection and proximal junctional kyphosis (PJK) and proximal junctional failure (PJF), the impact of minimally invasive spine surgery on the selection strategy of UIV were summarized. Results LSF can restore the biomechanical balance of the spine and reconstruct the physiological curve of the spine for ADS patients. LSF should be selected for ADS patients with severe scoliosis, vertebral rotation, and severe sagittal imbalance. For patients with poor general condition, UIV can choose the thoracic and lumbar vertebrae to reduce the operation time and intraoperative bleeding, which is conducive to early mobilization and reduce complications; for patients with good general condition, the upper thoracic vertebrae can be considered if necessary, in order to achieve satisfactory long-term effectiveness. However, the lower thoracic vertebra (T9、10) should be selected as much as possible to reduce postoperative complications such as PJK and PJF. In recent years, a new reference marker, the first coronal reverse vertebra was proposed, to guide the selection of UIV. But a large-sample multicenter randomized controlled study is needed to further verify its reliability. Studies have shown that different races and different living habits would lead to different parameters of the spine and pelvis, which would affect the selection of UIV. Minimally invasive surgeries have achieved satisfactory results in the treatment of ADS, but the UIV selection strategy in specific applications needs to be further studied. Conclusion The selection strategy of UIV in LSF has not yet been unified. The selection of UIV in the sagittal plane of the upper thoracic spine, the lower thoracic spine, or the thoracolumbar spine should comprehensively consider the biomechanical balance of the spine and the general condition of the patient, as well as the relationship between the upper horizontal vertebra, the upper neutral vertebra, and the upper end vertebra on the coronal plane.
Objective To analyze the prospective effect of pre-existing spinal stenosis of adjacent segment on the short-term effectiveness after lumbar fusion surgery. Methods A prospective comparative study was conducted to divide 183 patients with L4-S1 lumbar spinal stenosis who met the selection criteria between July 2015 and December 2017 into two groups according to the status of adjacent segment degeneration (ASD) judged by preoperative disc degeneration and spinal stenosis. There were 98 patients in group A (no degeneration of adjacent segments before operation) and 85 patients in group B (adjacent segments degenerated before operation). There was no significant difference in gender, American Society of Anesthesiologists (ASA) grade, body mass index (BMI), combined spondylolisthesis, and preoperative visual analogue scale (VAS) score of low back pain and leg pain, Japanese Orthopaedic Association (JOA) score, and Oswestry disability index (ODI) score between the two groups (P>0.05); the age of group A was significantly younger than that of group B (t=−3.560, P=0.000). The operation time, intraoperative blood loss, hospitalization stay, and perioperative complications were recorded and compared. The VAS score of low back pain and leg pain, JOA score, and ODI score at last follow-up were used to evaluate the effectiveness. The incidence of ASD after operation was compared between the two groups, and logistic regression was used to analyze the independent risk factors affecting the occurrence of ASD after operation. Results There was no significant difference in operation time, intraoperative blood loss, and hospitalization stay between the two groups (P>0.05). The incidence of perioperative complications in groups A and B was 13.3% and 20.0%, respectively, with no significant difference (χ2=1.506, P=0.220). Two groups of patients were followed up, the follow-up time of groups A and B was (24.9±8.8) months and (24.8±7.8) months, respectively, there was no significant difference (t=0.050, P=0.960). At last follow-up, no adjacent segment disease was found in either group. There was no significant difference in Pfirrmann grade between the two groups at last follow-up (P>0.05), and there was significant difference in Pfirrmann grade between the two groups before operation and at last follow-up (P<0.001). At last follow-up, 21 cases (21.4%) in group A and 53 cases (62.4%) in group B had ASD, with significant difference (χ2=31.652, P=0.000). The main cause of ASD was the severity of adjacent spinal canal stenosis. The clinical scores of the two groups at last follow-up were significantly improved when compared with those before operation (P<0.05). The JOA score of group A was significantly higher than that of group B at last follow-up (P<0.05). In group B, the VAS score of low back pain and ODI score in patients with ASD after operation at last follow-up were significantly higher than those in patients without ASD (P<0.05). logistic regression analysis showed that preoperative pre-existing degeneration and BMI were independent risk factors for ASD after operation (P<0.05). Conclusion Pre-existing mild spinal stenosis in adjacent segment can significantly affect the effectiveness, and can significantly increase the risk of ASD early after operation. The main pathological type of ASD was the severity of adjacent segment spinal stenosis. For preoperative assessment of pre-existing degeneration, we should evaluate the overall degeneration of the adjacent segment of the spinal canal, rather than simply evaluating the degeneration of the adjacent disc and facet joints.