Aim:. To present 11 patients with quadriplegia who developed severe lordoscoliosis or hyperlordosis. This is a rare deformity in children with CP, treatment is challenging and there are less than 20 patients ever reported. Method:. All patients underwent posterior spinal arthrodesis at mean age 14.6 years with mean follow-up 3.5 years. We measured all radiographic parameters including coronal and sagittal balance and sacral slope before and after surgery. Results:. Mean preoperative lumbar lordosis was 107°. This corrected to mean 63° at follow-up. Mean preoperative thoracic kyphosis was 13°. This improved to mean 47° at follow-up. Mean preoperative scoliosis was 80°. This corrected to mean 22o at follow up. Mean preoperative pelvic obliquity was 22°. This corrected to mean 4° at follow-up. Mean preoperative sacral slope was 80o. This corrected to mean 51o at follow-up. Mean preoperative coronal imbalance was 5.2 cm. This corrected to mean 0.6 cm at follow-up. Mean preoperative sagittal imbalance was 8 cm. This corrected to mean 1.6 cm at follow-up. Mean surgical time was 260 minutes. Mean intra-operative blood loss was 0.82 EBV. Mean stay in ICU was 3.6 and in hospital 15.2 days. Complications included 3 patients with severe blood loss (1.3–2 EBV), one patient with chest and one chest and urinary infection, and a patient with superior mesenteric artery syndrome. Increased preoperative lumbar lordosis and sacral slope correlated with surgical and postoperative morbidity. In contrast, there was no correlation between preoperative scoliosis or pelvic obliquity and surgical morbidity. Reduced lumbar lordosis and increased thoracic kyphosis correlated with better global sagittal balance at follow-up. Greater surgical time and blood loss correlated with increased postoperative morbidity. All 11 patients and their parents reported excellent feedback on the outcome of surgery with major improvement in physical appearance, sitting balance and relief of severe preoperative back pain. Discussion:.