Background: Patients with pre-existing cervical spinal canal stenosis (CSCS) are more likely to suffer from an extensional spinal cord injury (SCI). However, the appropriate surgical alternatives for extended cervical SCIs in individuals with pre-existing CSCS remain unknown. The purpose of this study was to evaluate the clinical efficacies of laminoplasty and posterior short-segment fusion (PSF) with laminoplasty and anterior short-segment fusion (ASF) in the treatment of these patients. Methods: The clinical data of 258 patients from six spine centers were included in this retrospective study. Patients were divided into two different groups based on the surgical approach: laminoplasty and PSF (PSF group) and laminoplasty and ASF (ASF group). ASIA grades and JOA scores were obtained before and after surgery to assess neurological function. Results: There were 116 patients in the PSF group and 142 patients in the ASF group. The average operation time, intraoperative blood loss, and hospital stay were 188 min, 298 ml, and 7.6 days, respectively, in PSF group, compared to 245 min, 366 ml, and 10.4 days in PSF group, respectively. Complete decompression was achieved in all patients, and fusion was achieved 6 months after surgery. A post-operative computed tomography scan revealed that 39/464 (8.4%) screws had perforated, but no neurovascular complications occurred. Both surgical strategies improved the ASIA grade and there was no significant difference between the two groups (P = 0.926). The JOA score improved from 6.21 ± 1.85 to 10.90 ± 3.56 in the PSF group and from 6.45 ± 2.17 to 11.48 ± 3.62 in the ASF group, but at the final follow-up, there was no significant difference between the two groups (P = 0.134). The incidence of post-operative complications in the ASF group (24/142, 16.9%) (P = 0.043) was higher than that in the PSF group (6/116, 5.17%). Conclusions: Cervical laminoplasty combined with short-segment transpedicular screw fixation is a reliable option to treat extensional cervical SCIs in patients with CSCS. This surgical strategy is beneficial for achieving sufficient cervical spinal cord decompression, preserving cervical spine stability, and avoiding extra anterior cervical decompression and fusion, thereby reducing surgery time, intraoperative blood loss volume, post-operative complication rate, and length of hospital stay. Relevance for Patients: Cervical laminoplasty combined with posterior segmental fusion (PSF) reduces operative time, bleeding, and complications and achieves adequate spinal cord decompression in the treatment of extension cervical SCI in patients with CSCS.