Axial symptoms after cervical laminoplasty with C3 laminectomy compared with conventional C3-C7 laminoplasty: a modified laminoplasty preserving the semispinalis cervicis inserted into axis.

STUDY DESIGN: Results of C4-C7 laminoplasty with C3 laminectomy and C3-C7 laminoplasty were compared. OBJECTIVES: To clarify prospectively whether the modified laminoplasty preserving the semispinalis cervicis inserted into C2 could reduce the axial symptoms compared with conventional laminoplasty reattaching the muscle to C2. SUMMARY OF BACKGROUND DATA: Intraoperative damage of the semispinalis cervicis is relevant to the development of axial symptoms after laminoplasty. In C3-C7 laminoplasty, however, it is difficult to preserve the muscle insertion into C2 while opening the C3 lamina. METHODS: The axial symptoms of 40 patients (Group A) with C4-C7 laminoplasty with C3 laminectomy were compared with those of 16 patients (Group B) with C3-C7 laminoplasty. The cross-sectional areas of the cervical posterior muscles were measured on magnetic resonance images. RESULTS: The number of patients with no postoperative axial symptoms increased (P = 0.035) from 19% to 52.5%, and the number of patients whose symptoms worsened after surgery decreased (P = 0.020) from 50% to 17.5%. The average atrophy rate of cross-sectional area was smaller (P < 0.001) in Group A (2.4%) than in Group B (10.8%). CONCLUSIONS: This method was less invasive to the cervical posterior muscles than C3-C7 laminoplasty. This is an effective procedure for preventing postoperative axial symptoms.