Essential lordosis revisited.

AIMS: Significant correction of an adolescent idiopathic scoliosis in the coronal plane through a posterior approach is associated with hypokyphosis. Factors such as the magnitude of the preoperative coronal curve, the use of hooks, number of levels fused, preoperative kyphosis, screw density, and rod type have all been implicated. Maintaining the normal thoracic kyphosis is important as hypokyphosis is associated with proximal junctional failure (PJF) and early onset degeneration of the spine. The aim of this study was to determine if coronal correction per se was the most relevant factor in generating hypokyphosis. METHODS: A total of 95 patients (87% female) with a median age of 14 years were included in our study. Pre- and postoperative radiographs were measured and the operative data including upper instrumented vertebra (UIV), lower instrumented vertebra (LIV), metal density, and thoracic flexibility noted. Further analysis of the post-surgical coronal outcome (group 1 < 60% correction and group 2 ≥ 60%) were studied for their association with the postoperative kyphosis in the sagittal plane using univariate and multivariate logistic regression. RESULTS: Of the 95 patients, 71.6% (68) had a thoracic correction of > 60%. Most (97.8%) had metal density < 80%, while thoracic flexibility > 50% was found in 30.5% (29). Preoperative hypokyphosis (< 20°) was present in 25.3%. A postoperative thoracic hypokyphosis was four times more likely to occur in patients with thoracic correction ≥ 60% (odds ratio (OR) 4.08; p = 0.005), after adjusting for confounding variables. This association was not affected by metal density, thoracic flexibility, LIV, UIV, age, or sex. CONCLUSION: Our study supports the 'essential lordosis' hypothesis of Roaf and Dickson, i.e. with a greater ability to translate the apical vertebra towards the midline, there is a commensurate lengthening of the anterior column due to the vertebral wedging. Cite this article: Bone Joint J 2020;102-B(4):513-518.

Role of Posterior Stabilization and Transpedicular Decompression in the Treatment of Thoracic and Thoracolumbar TB: A Retrospective Evaluation.

STUDY DESIGN: A retrospective study. OBJECTIVE: To evaluate the results of posterior pedicle-screw fixation with transpedicular decompression in 21 cases of thoracic and thoracolumbar spinal tuberculosis (TB) in terms of functional, neurological, and radiologic outcomes. SUMMARY OF BACKGROUND DATA: Spinal TB is predominantly an anterior disease that can lead to kyphotic deformity. Hence, anterior debridement and fusion was considered as the gold standard. However, with remarkable improvements in chemotherapy regimens and diagnostic tools, it is possible to detect the disease process early and treat them with less radical approaches. In the present study, authors have shown the results of posterior pedicle-screw fixation with transpedicular decompression in thoracic and thoracolumbar spinal TB. MATERIALS AND METHODS: The study reviewed 21 patients with thoracic or thoracolumbar TB with kyphotic deformity who were operated with posterior pedicle-screw fixation and transpedicular decompression (pus aspiration through a Jamshidi needle) with kyphosis correction for either neurological deficits (11) or intractable pain (10), not responding to at least 4-6 weeks of chemotherapy. Patients with <3 spinal segment involvement, <30 degrees kyphosis, and <50% vertebral body destruction were included in the study. RESULTS: The mean age of patients was 43.9 years and the mean kyphosis angle at the level of involvement was 21.61±3.72 degrees. Kyphosis improved postoperatively to 5.79±3.48 degrees. The mean follow-up period was 24.09 months, and final kyphosis correction was maintained at 8.74±3.65 degrees. Bony fusion was achieved in 80.5% cases. Eleven patients had neurological deficits, and all of them recovered. All patients had a Visual Analog score improvement from 9.52 to 2.57 postoperatively. CONCLUSIONS: Posterior stabilization with transpedicular decompression can be considered as a good treatment option for the management of thoracic and thoracolumbar TB in patients with <50% vertebral body destruction and <30-degree kyphosis. It provides rapid relief of instability pain, improvement of neurological deficit, and prevents progression of deformity.