Intraoperative ultrasound combined with MRI for evaluating float back and enlargement of the spinal cord after cervical laminoplasty in the management of degenerative cervical myelopathy

Abstract

Abstract Background Spinal cord floating and enlargement can develop after cervical laminectomy and laminoplasty, it determines whether completely decompress the cord. To assess the relationship between immediate float back and enlargement of the spinal cord after decompression and subsequent recovery of spinal cord function. Methods The parameters associated with float back and enlargement of the spinal cord in Intraoperative ultrasound (IOUS) and preoperative MRI were investigated. Spinal cord function recovery was also investigated as measured by the mJOA score at the one-year follow-up. Results The average preoperative mJOA score was 10.24 ± 2.59, the postoperative mJOA score was 14.51 ± 2.32, and improvements in mJOA score were achieved with an average recovery rate of 64.29%±27.70%. The immediate float back distance after decompression (1.01 ± 0.49 mm) was positively correlated with the one-year follow-up mJOA score (P < 0.01, r = 0.68) and the recovery rate of the mJOA score (P < 0.01, r = 0.72). The immediate enlargement of the spinal cord (1.39 ± 0.84 mm) was positively correlated with the one-year follow-up mJOA score (P < 0.01, r = 0.64) and the recovery rate of the mJOA score (P < 0.01, r = 0.71). Immediate enlargement of the front side of the spinal cord (1.39 ± 0.59 mm) was positively correlated with the one-year follow-up mJOA score (P < 0.01, r = 0.74) and the recovery rate of the mJOA score (P < 0.01, r = 0.73). Interestingly, only enlargement of the front side of the spinal cord was positively correlated with the preoperative mJOA score (P < 0.05, r = 0.36). Conclusions The extent of immediate spinal cord float back, and enlargement after decompression in French-door cervical laminoplasty can be evaluated using preoperative MRI combined with IOUS, and these indications help predict the clinical outcome after French-door expansive laminoplasty.