Sullivan Humbert G, Bertagnoli Rudolf, Nigogosyan Mark A, Ladwig Nicholas R, Born Hayley L, Cerniglia Molly M, Habbicht Hartmann, Mathiason Michelle A, McHugh Vicki L
Department of Neurosurgery, Gundersen Lutheran Health System, La Crosse, WI.
Department of Radiology, Gundersen Lutheran Health System, La Crosse, WI.
Int J Spine Surg. 2012 Dec 1;6:93-102. doi: 10.1016/j.ijsp.2011.12.004. eCollection 2012.
Prior studies of multilevel ProDisc-L (PD-L) implants (Synthes Spine, Inc., West Chester, Pennsylvania) using the standard US technique have used conventional radiography postoperatively. We found vertebral body-splitting fractures (VB-SFs) in interposed vertebral bodies after 5 sequential multilevel PD-L device implantations using the standard US technique. These were identified with postoperative computed tomography (CT) but were not visible on plain radiographs. In an additional patient, we found that a stress-relieving, pilot holes-only technique did not prevent VB-SFs. The 5 patients operated on with the standard technique composed the background series against which we compared the incidence of VB-SFs in patients operated on with a modification of the standard US technique-a combination of stress-relieving pilot holes, removal of cortex in the chisel path, and a fenestrated chisel (PH/CR/FC)-intended to reduce the incidence of VB-SFs in multilevel PD-L constructs.
Patients receiving multilevel PD-L implants at 2 sites-1 in the United States and the other in Germany-were operated on with the PH/CR/FC technique and their postoperative CT scans evaluated for the presence of VB-SFs. The frequency of VB-SFs in these patients was compared with that of the 5 patients from the background series who were operated on by the standard US technique. The groups' mean sex, age, body mass index, and vertebral body height, as well as average spinal T score, were also compared.
No fractures were found in 13 interposed vertebral bodies in 11 patients operated on with the PH/CR/FC technique, as compared with 4 VB-SFs and 1 anterior keel cut-to-anterior keel cut fracture in 5 interposed vertebral bodies in 5 patients operated on with the US technique (P ≤ .001). Although the sample sizes were small, this difference in fracture rate was not associated with sex, age, body mass index, or average spinal T score. At up to 13 months of follow-up of patients in the background series, we found that VB-SFs tend not to bridge with bone, instead forming sclerotic margins.
The PH/CR/FC technique studied reduced the incidence of VB-SF in multilevel PD-L implants. Because previously published multilevel studies did not use postoperative CT scans and because VB-SFs are not visible on conventional radiography, the incidence of VB-SFs in multilevel PD-L applications may be higher than previously reported. Our findings may contribute to prevention of complications in total disc replacement.
此前关于多级ProDisc-L（PD-L）植入物（美国宾夕法尼亚州韦斯特切斯特的Synthes Spine公司）使用标准美国技术的研究，术后采用的是传统放射成像。我们在连续5例使用标准美国技术植入多级PD-L装置后，发现置入椎体出现椎体劈裂骨折（VB-SF）。这些骨折通过术后计算机断层扫描（CT）得以识别，但在平片上不可见。在另一例患者中，我们发现一种仅钻导向孔以缓解应力的技术并不能预防VB-SF。采用标准技术手术的5例患者构成了背景系列，我们将其与采用标准美国技术改良术式——一种结合了缓解应力导向孔、凿骨路径去皮质及开窗凿（PH/CR/FC）——手术的患者的VB-SF发生率进行比较，该改良术式旨在降低多级PD-L结构中VB-SF的发生率。
在美国和德国两个地点接受多级PD-L植入的患者采用PH/CR/FC技术进行手术，并对其术后CT扫描评估是否存在VB-SF。将这些患者的VB-SF发生频率与背景系列中采用标准美国技术手术的5例患者进行比较。还比较了两组患者的平均性别、年龄、体重指数、椎体高度以及平均脊柱T值。
采用PH/CR/FC技术手术的11例患者的13个置入椎体未发现骨折，而采用美国技术手术的5例患者的5个置入椎体出现4例VB-SF和1例从前侧骨嵴切迹到前侧骨嵴切迹的骨折（P≤0.001）。尽管样本量较小，但骨折率的这种差异与性别、年龄、体重指数或平均脊柱T值无关。对背景系列患者进行长达13个月的随访时，我们发现VB-SF往往不会与骨愈合，而是形成硬化边缘。
所研究的PH/CR/FC技术降低了多级PD-L植入物中VB-SF的发生率。由于此前发表的多级研究未使用术后CT扫描，且VB-SF在传统放射成像上不可见，因此多级PD-L应用中VB-SF的发生率可能高于此前报道。我们的研究结果可能有助于预防全椎间盘置换中的并发症。
