Recent studies have shown that corrective surgery targeting the lumbar spine of adult spinal deformity (ASD) patients affects not only the lumbar lordosis but also the cervical spine balance. Evolution of the cervical spine lordosis after ASD surgery attracted attention of many surgeons, especially when dealing with concomitant cervical spondylosis. We conducted a prospective study, recruiting ASD patients underwent lumbar instrumentation and fusion and assessed the evolution of the C2-C7 cervical lordosis at three different times: preoperative, postop and at final follow-up. Neck pain intensity (assessed by using NDI) was also collected in parallel to radiographic parameters. Risk factors of worsening cervical symptoms were identified using univariate analysis. There were 72 patients (12 men/ 60 women) with mean age of 64 and mean duration of FU of 2.5 years. We noticed a transient decrease of the cervical spine lordosis right after operation and then it increased again at final FU, with the C2-C7 angles at preop, postop and at final FU evaluations were 20o, 10o and 15o, respectively (p<0.05). In regards to risk factors of increased postoperative neck pain, only preop T1slope < 40o was the risk factor (OR=9.7; p = 0.036). Preop neck pain severity, amount of lumbar lordosis correction, change in SVA and change of cervical lordosis after surgery did not affect the final cervical status. When dividing participants into two groups based on T1slope, we found that the cervical lordosis of group T1 slope <40o was always inferior than that of group T1 slope > 40o with statistical significance (16o versus 24o at preop, 4o versus 10o at postop and 15o versus 18o at final FU assessment; p<0.05). Our findings were in line with the results of other studies, demonstrating the relationship between the cervical lordosis and the global sagittal balance of the entire body. Among cervical parameters, T1 slope, similarly to the sacral slope, plays the crucial role in cervical sagittal balance and will determine other indices. Care should be taken when correcting patients with flat back and low T1 slope as the temporary decrease of postop cervical lordosis may negatively affect preexisting cervical spondylosis.