Evaluation of Proximal and Distal Junctional Kyphosis After Posterior Instrumentation and Fusion in Scheuermann’s Kyphosis

Purpose: To evaluate the frequency, risk factors and effects of distal junction kyphosis (DJK) and proximal junction kyphosis (PJK), which are common in patients who undergoposterior instrumentation and fusion due to Scheuerman kyphosis (SK), on patient quality of life. Patients and Methods: Sixty-threepatients who underwent posterior instrumentation and fusion due to Scheuerman kyphosis between 2012 and 2017 at The Health Sciences University, Haydarpaşa Numune Training and Research Hospital Orthopedics and Traumatology Clinic and who served asregular controls were retrospectively analyzed. All patients were operated on by the same surgical team. Twenty-sixof the patients were male,and 37 were female. The mean age was 26.83 ± 9.08 years (range: 17–50 years). Patients who had a follow-up period of less than 2 years, had intraspinal pathology on preoperative MR imaging, had kyphosis forother reasons and had previously undergone spinal surgery or combined surgery (anterior-posterior) were excluded. The patients were divided intotwo groups according to the detection of PJK and DJK. PJK developed in 22 patients, DJK in three patients, and both PJK and DJK in two patients. Results: The mean age of patients (36.4±12.54 years) with DJK was significantly greater than that of patients without DJK (p <0.05). There was no statistically significant difference in sex between the groups with DJK (p> 0.05). There was no statistically significant difference between the patients who developed PJK and the other patients in terms of the mean age (25,96±8,05) or sex distribution (p> 0.05). Stablesagittal vertebrae (SSVs) were not included in the fusion in 80% of the patients who developed DJK. This differencewas statistically significant(p <0.05). Lumbar lordosis (LL) (24,46±8,01), sacral slope (SS) (26,36±6,55) and pelvic incidence (PI) (11,92±8,72) values were significantly lower in patients with DJK than in those without DJK (p <0.05). There was no statistically significant difference in the sagittal vertical axis (SVA) (-29,75±45,92), thoracickyphosis (TK) (51,32±11,26), pelvic tilt (PT) (12,05±4,49), LL (46,1±13,39), SS (38,09±7,55) or PI (50,14±9,71) parameters betweenpatients with PJK andother patients (p> 0.05). There was no statistically significant difference between the SRS-24 score and the SF-36 score in patients with PJK or DBK (p> 0.05). Conclusion: A significant relationship was found between low LL, SS, PI and DJK. The mean age of patients with DJK was significantly greater. There was no significant relationship between clinical evaluations of the SRS-24 and SF-36 scores and the development of DJK and PJK.