摘要目的:探讨儿童骶尾部小凹与终丝变性的关系。方法:纳入2015年4月至2020年3月上海交通大学医学院附属上海儿童医学中心神经外科以发现骶尾部小凹为主诉就诊、且行腰椎MRI检查的儿童343例。对MRI发现终丝变性(MRI阳性)或虽然MRI为阴性但有明显脊髓拴系症状的患儿行手术治疗。回顾性分析有骶尾部小凹的儿童终丝变性的发生情况，并分析不同影像学表现患儿终丝变性的差异。结果:343例患儿中，经手术证实166例(48.4%)存在终丝变性。术前MRI阳性者152例(44.3%)，阴性者191例(55.7%)；152例MRI阳性患儿中，52例矢状位及轴位像均可见终丝变性，100例仅轴位像可见终丝变性；191例MRI阴性者中，14例(7.3%)因存在明显脊髓拴系症状行手术探查，术中均发现终丝变性。术中显示，MRI矢状位及轴位像均为阳性组、仅轴位像阳性组、MRI阴性组的终丝最大直径分别为(3.58±1.17)mm、(2.32±0.56)mm、(2.04±0.37)mm，差异有统计学意义( P<0.001)。术后病理学显示，52例MRI矢状位及轴位像均为阳性组中，脂肪变性50例(96.2%)，纤维脂肪变性2例(3.8%)；100例仅轴位像阳性组中，脂肪变性95例(95.0%)，纤维脂肪变性4例(4.0%)，纤维变性1例(1.0%)；14例MRI阴性组中，脂肪变性7例，纤维脂肪变性1例，纤维变性6例；3组病理学类型的差异有统计学意义( P<0.001)。166例手术的患儿均无手术相关的脊髓神经损伤症状，无脑脊液漏。术后6个月随访显示，术前有症状的患儿症状均明显改善。 结论:有骶尾部小凹的儿童发生终丝变性的概率高。MRI轴位像扫描有助于提高MRI的阳性发现率；MRI阴性者不能排除终丝变性。MRI终丝变性检出率与终丝直径和病理学类型相关，终丝纤维变性不易被MRI检出。

abstractsObjective:To explore the relationship between sacrococcygeal dimples and filum terminale degeneration in children.Methods:A total of 343 children who visited the Department of Neurosurgery of Shanghai Children′s Medical Center, Shanghai Jiao Tong University School of Medicine from April 2015 to March 2020 with the main complaint of sacrococcygeal dimples who underwent MRI lumbar spine examination were included. Surgical treatment was performed for children with filum terminale degeneration found on MRI (MRI positive) or with obvious tethered cord symptoms despite negative MRI findings. The occurrence of filum terminale degeneration in children with sacrococcygeal dimples was retrospectively analyzed, and the differences in filum terminale degeneration in children with different imaging manifestations were analyzed.Results:Among the 343 children, 166 (48.4%) were confirmed to have filum terminale degeneration by surgery. Preoperative MRI was positive in 152 cases (44.3%) and negative in 191 cases (55.7%). Among the 152 children with positive MRI, 52 cases showed degeneration of the filum terminale in both sagittal and axial images, and 100 cases showed degeneration of the filum terminale only in axial images. Among the 191 children with negative MRI findings, 14 cases (7.3%) underwent surgical exploration due to obvious symptoms of tethered cord, and degeneration of the filum terminale was found in all cases during the operation. Intraoperatively, the maximum diameter of the filum terminale in the group with positive sagittal and axial MRI images, the group with positive axial images only, and the group with negative MRI images was 3.58±1.17 mm, 2.32±0.56 mm, and 2.04±0.37 mm, respectively, with statistically significant differences ( P<0.001). Postoperative pathology showed that among the 52 cases with positive MRI sagittal and axial images, 50 cases (96.2%) had fatty degeneration and 2 cases (3.8%) had fibrofatty degeneration; among the 100 cases with positive axial images only, 95 cases (95.0%) had fatty degeneration, 4 cases (4.0%) had fibrofatty degeneration, and 1 case (1.0%) had fibrotic degeneration; among the 14 cases with negative MRI findings, 7 cases had fatty degeneration, 1 case had fibrofatty degeneration, and 6 cases had fibrotic degeneration; the differences in pathological types among the three groups were statistically significant ( P<0.001). None of the 166 children who underwent surgery had surgery-related nerve injury symptoms or cerebrospinal fluid leakage. Follow-up at 6 months post surgery showed that the symptoms of children with preoperative symptoms were significantly improved. Conclusions:Children with sacrococcygeal dimples have a high probability of filum terminale degeneration. MRI axial scanning can help improve the positive detection rate of MRI. Filum terminale degeneration cannot be ruled out in patients with negative MRI findings. The detection rate of filum terminale degeneration on MRI is related to the diameter of the filum terminale and the pathological type. Filum terminale fiber degeneration is not easily detected by MRI.