Borghi Alessandro, Rodgers Will, Schievano Silvia, Ponniah Allan, Jeelani Owase, Dunaway David
UCL Great Ormond Street Institute of Child Health and Great Ormond Street Hospital for Children.
Royal Free Hospital, London, UK.
J Craniofac Surg. 2018 Jan;29(1):45-48. doi: 10.1097/SCS.0000000000004025.
Treatment of unicoronal craniosynostosis is a surgically challenging problem, due to the involvement of coronal suture and cranial base, with complex asymmetries of the calvarium and orbit. Several techniques for correction have been described, including surgical bony remodeling, early strip craniotomy with orthotic helmet remodeling and distraction. Current distraction devices provide unidirectional forces and have had very limited success. Nitinol is a shape memory alloy that can be programmed to the shape of a patient-specific anatomy by means of thermal treatment.In this work, a methodology to produce a nitinol patient-specific distractor is presented: computer tomography images of a 16-month-old patient with unicoronal craniosynostosis were processed to create a 3-dimensional model of his skull and define the ideal shape postsurgery. A mesh was produced from a nitinol sheet, formed to the ideal skull shape and heat treated to be malleable at room temperature. The mesh was afterward deformed to be attached to a rapid prototyped plastic skull, replica of the patient initial anatomy. The mesh/skull construct was placed in hot water to activate the mesh shape memory property: the deformed plastic skull was computed tomography scanned for comparison of its shape with the initial anatomy and with the desired shape, showing that the nitinol mesh had been able to distract the plastic skull to a shape close to the desired one.The shape-memory properties of nitinol allow for the design and production of patient-specific devices able to deliver complex, preprogrammable shape changes.
单冠状缝早闭的治疗是一个具有手术挑战性的问题，因为冠状缝和颅底受累，伴有颅骨和眼眶的复杂不对称。已经描述了几种矫正技术，包括手术骨重塑、早期条带颅骨切开术加矫形头盔重塑和牵引。目前的牵引装置提供单向力，且成功率非常有限。镍钛诺是一种形状记忆合金，可通过热处理将其编程为患者特定解剖结构的形状。在这项工作中，提出了一种制造镍钛诺患者特定牵引器的方法：对一名16个月大的单冠状缝早闭患者的计算机断层扫描图像进行处理，以创建其颅骨的三维模型并确定术后理想形状。从镍钛诺片材制作出一个网格，将其成型为理想的颅骨形状并进行热处理，使其在室温下具有可塑性。之后将网格变形以附着到快速成型的塑料颅骨上，该塑料颅骨是患者初始解剖结构的复制品。将网格/颅骨结构放入热水中以激活网格的形状记忆特性：对变形的塑料颅骨进行计算机断层扫描，以将其形状与初始解剖结构和所需形状进行比较，结果表明镍钛诺网格能够将塑料颅骨牵引到接近所需形状的形状。镍钛诺的形状记忆特性允许设计和制造能够提供复杂的、预编程形状变化的患者特定装置。
