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 Table of Contents  
CASE REPORT
Year : 2020  |  Volume : 53  |  Issue : 2  |  Page : 74-77

Utilization of the 3-D image and printed model as a surgical plan: An experience of a multi-level cervical spine fracture


1 Department of Neurosurgery, Chi-Mei Medical Center, Tainan, Taiwan
2 Department of Neurosurgery, Chi-Mei Medical Center; Department of General Education, Southern Taiwan University of Science and Technology, Tainan, Taiwan
3 Department of Neurosurgery, Chi-Mei Medical Center; Department of Medical Research, Chi.Mei Medical Center, Tainan, Taiwan

Date of Submission06-Oct-2019
Date of Decision28-Oct-2019
Date of Acceptance07-Jan-2020
Date of Web Publication23-Apr-2020

Correspondence Address:
Dr. Jinn-Rung Kuo
No. 901 Chung Hwa Road, Yung Kang City, Tainan
Taiwan
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/fjs.fjs_80_19

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  Abstract 


The placement of cervical spine pedicle screws and lateral mass screws are technically demanding due to their proximity to vital structures such as the spinal cord and the vertebral arteries. In the case of multilevel cervical spine trauma, the fracture location and the size of the pedicle often limits the choice of the pedicle screw. This case report analyses the possibility of pedicle screw placement in the upper cervical spine with the help of a three-dimensional (3D)-image model as preoperative planning. Here, we present a 29-year-old patient who suffered from a motor vehicle accident. He had a cervical injury for which we designed a reduction plan with the help of 3D models shaped from his computed tomography image. The operation of reduction and fixation was performed from the level of C5 to T1 smoothly and no complication occurred through to follow-up. As shown in this case, 3D reconstruction technology can help us plan for reduction surgery in a highly complicated case of cervical spine fracture and provide the operator with a better way to visualize the surgical anatomy. 3D reconstruction technology can help us plan for reduction surgery and perform the preoperative surgical simulation. The surgeon can select the size of the pedicle screw correctly and save the operative time.

Keywords: Three-dimensional printing, cervical spine fracture, lateral mass screw, pedicle screw, surgical plan


How to cite this article:
Zheng HX, Lee YL, Wang CC, Kuo JR. Utilization of the 3-D image and printed model as a surgical plan: An experience of a multi-level cervical spine fracture. Formos J Surg 2020;53:74-7

How to cite this URL:
Zheng HX, Lee YL, Wang CC, Kuo JR. Utilization of the 3-D image and printed model as a surgical plan: An experience of a multi-level cervical spine fracture. Formos J Surg [serial online] 2020 [cited 2020 May 28];53:74-7. Available from: http://www.e-fjs.org/text.asp?2020/53/2/74/283126




  Introduction Top


Three-dimensional (3D)-printed models have become a popular tool for surgeons to outline preoperative plans in the fields of cardiovascular surgery,[1] plastic surgery,[2] and neurosurgery.[3] Most of these clinical applications in spine surgery focused on the customized implant design.[4] Even though there is a trend to make the use of the spine screw guiding plate to facilitate the operation, it takes time to produce and design a sterilized guiding plate.[5] Here, we present a case of a multilevel cervical spine fracture with surgical planning for reduction and fixation created with the help of a 3D-printed and image model. Through this case, we wish to illustrate the advantage of the 3D-printed model and its usefulness of 3D-image in surgical planning and communication with patients and family before the surgery.


  Case Report Top


A 29-year-old male with the medical history of the recreational drug abuse and prior auditory hallucinations had a car accident on August 28, 2018. His consciousness level on arrival at the emergency department was clear with a Glasgow coma scale of 15. Neurologic examination revealed increased deep tendon reflex in bilateral lower limbs and limitation of range of motion. Cervical spine X-ray showed C7 pars fracture with mild spondylolisthesis at the C6/7 level [Figure 1]a and computed tomography (CT) of the brain showed no intracranial hemorrhage. Cervical spine CT was thus arranged and showed bilateral C6 cervical spine lamina fracture with right pedicle fracture, combined with C6/7 bilateral locked facet joints. There was also minimal C5/6 spondylolisthesis and C7 left pedicle incomplete fracture, which causes an unstable cervical spine [Figure 1]b, [Figure 1]c, [Figure 1]d, [Figure 1]e, [Figure 1]f, [Figure 1]g, [Figure 1]h. Thus, a cervical spine magnetic resonance imaging was arranged for suspicion of spinal cord compression and it showed cervical spondylosis with mild disc protrusion at C4/5 and C6/7 without cord compression, there was bilateral C6/7 facet perched subluxation and C5/6 interspinous process ligament tear.
Figure 1: (a) The plain X-ray of lateral view of cervical spine. (b-h) The axial and sagittal view of cervical spine

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After admission, the patient's upper limbs Medical Research Council muscle power grading worsened from 5 to 3 after 2 days of conservative neck collar treatment. The patient also complained of neck pain and stiffness. Surgical intervention was recommended for the first time; however, the patient was so hesitated. For provided more detailed information about the surgical planning and obtaining a spine solid model, the digital imaging and communications in medicine from the thin-cut CT image was used to build the 3D-printed model using the software: Materialise Mimics Medical (Technologielaan, Leuven, Belgium, version 22.0) and postprocessing software: 3-Matic Medical (Technologielaan, Leuven, Belgium, version 14.0) [Figure 2]a.
Figure 2: (a-c) The three-dimensional model created with computer software and then be manufactured into real three-dimensional print object (d)

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For stability concerns, we prefer the pedicle screw to the lateral mass screw.[6] However, the risks of complications for high cervical pedicle screws are extremely high.[7] To prevent such complications, we chose to abandon screw implantation for the C6 right pedicle and C7 left pedicle. To analyze the possibility of pedicle screw placement, we defined the Hounsfield unit (HU) of the cancellous bone as 148 HU ~ 661 HU and the cortical bone as 662 HU ~ 1988 HU. The cancellous part and the cortical part of the pedicle can thus be identified separately and then be reconstructed into 3D images. After reconstructing the 3D image, we defined the centerline along the center of the cortex and cancellous bone of the pedicle. With the definition of the centerline, we can measure the pedicle diameter along the continuous centerline. Pedicle diameter was measured in two ways: the best-fit diameter and the minimal diameter. These principles are based on overall bone structure as well as cancellous bone diameter to evaluate the relationship between the screw and the bone structure. The best-fit diameter follows the cancellous bone in bilateral pedicles and is measured continuously in a cone shape through the pedicle length, and the mean diameter value was recorded. Pedicle trajectory for the screws is adjusted to measure the minimal diameter [Figure 2]b and [Figure 2]c, which is the smallest distance from the centerline to the cortex surface. With the recording of continuous values of the minimal diameter along the pedicle, it can be clearly identified the small thinnest part of the pedicel and thus can help select the proper diameter of the pedicle screw which will not penetrate out of the pedicle. Finally, we used the lateral mass screw with a length of 16 mm and diameter of 3.5 mm for the right side of C5 and the pedicle screw with a length of 24 mm and diameter of 3.5 mm for the left side of C5. The pedicle screw used for the left side of C6 was in the length of 26 mm and diameter of 4 mm and the right side of C7 were in the length of 28 mm and diameter of 4 mm. At T1 level, the pedicle screws were in length of 26 mm and diameter of 4 mm for the left side and in length of 30 mm and diameter of 4 mm for the right side.

The model was then manufactured by a 3D-printer with polylactic acid for surgical simulation [Figure 2]d immediately after the CT examination was finished. Printing takes 3 h from C5-6-7-T1. Finally, the patient accepted operation after we explained the surgical plan assistant with the 3D model and imaging. The cervical posterior laminectomy for C6 and posterior fixation with the Oasys system for C5-6-7-T1 was performed smoothly for this patient without complications on 5 September 2018 [Figure 3]a and [Figure 3]b. The overall operation time took 4 h and 15 min from the anesthesia to the closure of wound and the average screw implantation time was about 3 min.
Figure 3: (a and b) The postoperative plain X-ray of cervical spine

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  Discussion Top


After the complete image survey of the cervical spine, we discussed reduction surgery with the patient and his family. However, the patient and his family were hesitant about surgery due to the uncertain risks and benefits of surgery. We demonstrated the lesion and the plan reduction and fixation surgery to the patient and his family using the 3D model, and they had more comprehension of the procedure, which led to the decision to accept surgery. This shows that 3D models can provide us with a good communication tool with patients before the surgery.

From the perspective of the operation, a 3D reconstructed image can help us select either a pedicle screw or a lateral mass screw by evaluating the diameter we measured from the 3D model. [Figure 4] shows the diameter we measure from the software Materialize and the pedicle screws we selected for implantation (with exception of the right C6 and left C7 pedicle which were fractured and the right C5 which diameter was too thin for pedicle screw implantation). With the help of the 3D-printed model, we can correctly plan for the screws depending on the size of the pedicle diameter and its optimal length and determine whether pedicle screws or lateral mass screws are preferable in an individualized setting of upper cervical spine trauma. In this case, we spent about 3 min for one screw implantation. In general, it took us about more than 6 min in one pedicle screw instrumentation due to the more fluoroscopy confirmation without the help of the 3D model. The 3D model technique can really reduce surgical time and the blood loss was also less because all screws were implanted in one time without readjustment.
Figure 4: Pedicle analysis for the narrowest part

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Besides, the distribution of cancellous bone was analyzed and measured for the prediction of the strength of the pedicle screw. We can simulate the condition of the pedicle screw instrumentation with the software in the computer to make sure no breach out regarding the size of pedicle screw or the plan of pedicle screw instrumentation should be abandoned and turned to lateral mass screw implantation. In comparison to the traditional 2D image, 3D image can provide a more precise and unlimited method for the measurement of the pedicle, which needs not to be restricted to the angle of the CT slice cut. The trajectories of the screws can also be planned as a thorough preoperative preparation to prevent catastrophic iatrogenic injury and can be produced into a real sized 3D print model as the preoperative simulation for the well-experienced neurosurgeon.


  Conclusion Top


3D reconstruction technology can help us plan for reduction surgery in a highly complicated case of cervical spine fracture and provide the operator with a better way to visualize the surgical anatomy. It can also be a good communication tool with patients before the surgery. Surgeons can perform surgical simulation and select the correct screw size for the pedicle screw implantation to save the operative time with the help of the 3D printing model.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published, and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Milano EG, Capelli C, Wray J, Biffi B, Layton S, Lee M, et al. Current and future applications of 3D printing in congenital cardiology and cardiac surgery. Br J Radiol 2019;92:20180389.  Back to cited text no. 1
    
2.
Ghai S, Sharma Y, Jain N, Satpathy M, Pillai AK. Use of 3D printing technologies in craniomaxillofacial surgery: A review. Oral Maxillofac Surg 2018;22:249-59.  Back to cited text no. 2
    
3.
Randazzo M, Pisapia JM, Singh N, Thawani JP. 3D printing in neurosurgery: A systematic review. Surg Neurol Int 2016;7:S801-S809.  Back to cited text no. 3
    
4.
Wilcox B, Mobbs RJ, Wu AM, Phan K. Systematic review of 3D printing in spinal surgery: The current state of play. J Spine Surg 2017;3:433-43.  Back to cited text no. 4
    
5.
Wu HH, Su IC, Hsieh CT, Fang JJ, Chang CJ. Accuracy and safety of using customized guiding templates for cervical pedicle screw insertion in severe cervical deformity, fracture, and subluxation: A retrospective study of 9 cases. World Neurosurg 2018;116:e1144-52.  Back to cited text no. 5
    
6.
Hong JT, Qasim M, Espinoza Orías AA, Natarajan RN, An HS. A biomechanical comparison of three different posterior fixation constructs used for c6-c7 cervical spine immobilization: A finite element study. Neurol Med Chir (Tokyo) 2014;54:727-35.  Back to cited text no. 6
    
7.
Nakashima H, Yukawa Y, Imagama S, Kanemura T, Kamiya M, Yanase M, et al. Complications of cervical pedicle screw fixation for nontraumatic lesions: A multicenter study of 84 patients. J Neurosurg Spine 2012;16:238-47.  Back to cited text no. 7
    


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  [Figure 1], [Figure 2], [Figure 3], [Figure 4]



 

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