Atypical Scheuermann's disease with severe kyphosis and negative sagittal balance in the thoracolumbar region: A case report and literature review.

INTRODUCTION AND IMPORTANCE: Scheuermann's kyphosis is a structural deformity of the thoracolumbar spine that is classified in typical (thoracic) and atypical (lumbar and thoracolumbar) Scheuermann's disease. Surgical intervention is reserved for those with progressive kyphosis, intractable pain and neurological impairment. Although, previous literature focuses on the correction of the thoracic kyphosis (TK), recent lines of evidence recommend considering all the sagittal balance parameters when performing a surgery. We herein, report a posterior-only approach in a patient with Scheuermann's kyphosis, considering all the sagittal balance parameters. CASE PRESENTATION: The patient was a 17-year-old boy with a kyphotic deformity in the lumbar region, with urinary retention and upper back intractable pain. The preoperative physical examination was normal except for a kyphotic gait. The patient was first treated with thoracic lumbosacral orthoses (TLSO) brace that was not effective; consequently, the patient underwent posterior only approach (pedicular screw fixation along with Smith-Peterson osteotomy) with correction of the sagittal balance and kyphosis. The patient's sign and symptoms improved significantly. The surgery was uneventful and no complication was recorded. The 1-year follow-up revealed normal neurological examination and normal sagittal balance parameters. CLINICAL DISCUSSION: Atypical Scheuermann's kyphosis with neurological impairment and progressive kyphosis should be treated with surgical intervention. CONCLUSION: Considering the sagittal parameters of the spine, the surgical intervention should be designed to correct the kyphosis and the other indices of the sagittal balance. Posterior-only approach is safe and effective method for correction of the TK and improving the signs and symptoms of the patients.

An optimal general type-2 fuzzy controller for Urban Traffic Network.

Urban traffic network model is illustrated by state-charts and object-diagram. However, they have limitations to show the behavioral perspective of the Traffic Information flow. Consequently, a state space model is used to calculate the half-value waiting time of vehicles. In this study, a combination of the general type-2 fuzzy logic sets and the Modified Backtracking Search Algorithm (MBSA) techniques are used in order to control the traffic signal scheduling and phase succession so as to guarantee a smooth flow of traffic with the least wait times and average queue length. The parameters of input and output membership functions are optimized simultaneously by the novel heuristic algorithm MBSA. A comparison is made between the achieved results with those of optimal and conventional type-1 fuzzy logic controllers.