Postoperative C5 palsy is a clinically important complication after cervical laminoplasty, and prophylactic C4/5 foraminotomy has been advocated despite insufficient evidence. The C3 dome C7 reverse dome open-door laminoplasty technique was designed to preserve C3 and C7 posterior elements and prevent excessive posterior spinal cord shift. We retrospectively reviewed 86 consecutive patients who underwent this technique. The primary outcome was postoperative C5 palsy. Secondary outcomes were Japanese Orthopaedic Association (JOA) score and recovery rate by Hirabayashi’s method. C4/5 foraminal diameter was measured on axial T2-weighted MRI; stenosis was defined as <2.0 mm. Mean age was 63.1 years, 68.6% were men, and cervical spondylotic myelopathy was the most common indication. Twenty-five patients (29.1%) had preoperative C4/5 foraminal stenosis, and 18 underwent prophylactic C4/5 foraminotomy. Mean JOA improved from 12.4 preoperatively to 14.9 at 3 months, 15.7 at 1 year, and 16.0 at 2 years (p<0.001), with a mean 2-year recovery rate of 64.4%. No patient developed C5 palsy (0%); no revision surgery was required at final follow-up. Baseline characteristics were comparable between the foraminotomy and no-foraminotomy groups, although the 2-year JOA score was higher without foraminotomy (16.2 vs 15.0, p=0.04). These findings suggest that routine prophylactic C4/5 foraminotomy may not be necessary during C3 dome C7 reverse dome open door laminoplasty, including for patients with C4-C5 foraminal stenosis or spinal cord signal changes. The technique may lower C5 palsy risk, and selective foraminotomy may be considered only when neuromonitoring indicates possible intraoperative C5 root injury or when preoperative radiculopathy is present.