275. The effect of the distal level or proximal level on post-laminoplasty loss of cervical vertebra lordosis

Abstract

BACKGROUND CONTEXT Open-door laminoplasty is a useful operation in the surgical management of cervical myelopathy with favorable outcomes and relatively low complications. One potential undesirable outcome is a decrease in cervical lordosis postoperatively. It is unknown whether the most the distal level or proximal level undergoing laminoplasty affects the magnitude of loss of lordosis. PURPOSE This study aimed to compare the loss of cervical lordosis postoperatively in patients for whom the most proximal level undergoing laminoplasty is proximal level. STUDY DESIGN/SETTING A retrospective radiographic review as a center was carried out. PATIENT SAMPLE A total of 513 patients at a single institution who underwent plated open door laminoplasty for cervical myelopathy by multiple surgeons over a 5-year period were included. OUTCOME MEASURES The primary outcome was change in cervical lordosis, which was the difference in C2-T1 Cobb angle between the postoperative and preoperative film. METHODS Patients were divided into two groups based on the most proximal vertebral level undergoing laminoplasty. There were 157 patients who underwent laminoplasty beginning at C2, whereas 171 patients underwent laminoplasty beginning at C3, whereas 137 patients underwent laminoplasty beginning at C4, whereas 48 patients underwent laminoplasty beginning at C5. The C2-T1 Cobb angle was measured on the preoperative film and on the final postoperative follow-up film. The difference between these values was calculated for each patient, and the mean of the differences for the C3 group was compared with that of the C4 group. RESULTS When C2 was the proximal plated laminoplasty level, loss of lordosis averaged 12°. When C3 was the proximal plated laminoplasty level, loss of lordosis averaged 10°. When C4 was the proximal plated laminoplasty level, loss of lordosis averaged 4°. In contrast, when C5 was the proximal plated level, loss of lordosis was significantly less and averaged only 2° (p=0.041). In the group as a whole, mean preoperative lordosis was 21° compared with 12° postoperatively, for an overall 8° loss of lordosis. CONCLUSIONS Starting the laminoplasty at C4 led to significantly less loss of lordosis than starting at C2-C3. When the pattern of spinal cord compression does not require laminoplasty at C3, consideration should be given to making C4 the most cephalad laminoplasty level rather than C3 to better preserve lordosis. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.