In this article, we are going to discuss the Future of Cervical Spine Surgery a complete information step by step. The manufacture of individualized implants is possible on the basis of recent research on the spine. Using patient-specific computed tomography or magnetic resonance tomography data, an individual spine model can be rendered. With the help of such a model, an implant can be configured individually. In addition, the finite element method could be used to virtually test the biomechanical behaviour of the cervical spine after implantation. Another area of research is biological disc replacement through the autologous transplant section of chondrocytes. In the thoracic and lumbar spine, the augmentation of screws with polymethyl methacrylate in severe osteoporosis has been established for many years. Thus, this technique could also be used for the cervical spine.
What is Cervical Spine
The cervical spine is the uppermost part of the spine, is located between the skull and the thoracic vertebrae and consists of seven different vertebrae, two of which have unique names: The first cervical vertebra (C1) is known as the atlas. The second cervical vertebra (C2) is called the axis
The benefit of Total Disc Replacement
Despite the numerous prostheses for total disc replacement available on the market, there is still ongoing discussion about and controversy over the benefit of these relatively expensive implants (Bae et al. 2015; Radcliff et al. 2015). In particular, the avoidance of adjacent degeneration is still the focus of research (Richards 2012). Furthermore, the follow-up intervals of most studies are relatively short, since most implants have been on the market for less than 10 years.
Autologous Chondrocyte Transplantation for Disc Replacement
In the future, there will likely be a trend towards biological replacement with autologous chondrocytes. This could be an alternative to mechanical prostheses for total disc replacement. So far, however, no valid data are available for this procedure. Case reports and experiences come from a Phase I study of the lumbar spine. These results can lead to a useful and safe alternative to mechanical disc replacement. But valid results will probably only be available years later.
Augmentation of Screws in Fusion Cases
The use of augmented screws has been established in lumbar backbone surgical treatment for osteoporosis or revision instances. A pre-situation is the usage of cannulated screws to permit the utility of fluid polymethylmethacrylate (PMMA) into the cancellous bone. After the PMMA hardens, a good junction among screws and the bone emerges. Reports of PMMA augmentation in screwing the dens axis (Kohlhof et al. 2013) and in anterior plating of the cervical backbone (Jo et al. 2012; Waschke et al. 2013) are available from small affected person populations present process cervical surgical treatment. We used PMMA augmentation for a secondary breakout after anterior plating in sufferers with osteoporosis (Fig. 11.1).
With growing lifestyles expectancy, an increasing number of sufferers with osteoporosis will probably need to be treated, and for that reason, the range of instances with a demonstration for PMMA augmentation of screws will increase. As referred to in Chap. 7.2.2 web page 67, the usage of spreading screws did now no longer win popularity seeing that reviews are available of extended breakout rates after the use of that form of a screw, even in sufferers without osteoporosis (König and Spetzger 2014). The use of PMMA has additional disadvantages, together with an exothermal hardening technique and the discharge of poisonous remnant monomers. Therefore the usage of opportunity substances and substances has been investigated (Hollstein 2003), however to date there are no noteworthy options to PMMA.
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Manufacturing and Implantation of an Individualised 3-Dimensional Printed Titanium Cage for Cervical
Fusion
This topic of The Future of Cervical Spine Surgery is divided into 5 categories which are given below:-
01. General Considerations
At present, anterior cervical discectomy and fusion (ACDF) with implantation of cages product of numerous biocompatible materials, without or with anterior plating, is the same old surgical remedy for spondylotic cervical myelopathy and/or radiculopathy (Cabraja et al. 2012; Kolstad et al. 2010; Wu et al. 2012; Yamagata et al. 2012). The severe cervical cages supplied through the industry greater or much less mimic the anatomy of the intervertebral disc space, while the size and layout of the cages are tailored to fit the average sizes and styles of a patient’s intervertebral discs. The method of standalone cages without a further plate reduces the invasiveness of the procedure and is gaining usual acceptance.
The philosophy of our innovative project was to adapt a cage to a patient’s person anatomy and not – as usual – adapt the patient’s anatomy to a commercially to be had cage. This improvement ambitions to create an implant that perfectly suits the person endplates of the adjoining vertebral our bodies on the way to keep away from fusion complications which includes secondary dislocation or subsidence of the cage. Together with our business partners, we created a patient-specific and individualised cervical cage for ACDF.
This record summarises our interdisciplinary clinical industrial cooperation with computer-aided planning (virtual truth interactive simulation), production through 3-dimensional (3-d) printing (selective laser melting) and surgical implantation of an individualised cervical cage. Simulation and making plans have been completed with 3-d Systems, Rock Hill, SC. The production and 3-d printing of the cage have been completed through Emerging Implant Technologies GmbH (EIT), Tuttlingen, Germany. The surgery become completed on the Department of Neurosurgery, Städtisches Klinikum Karlsruhe (SKK), Karlsruhe, Germany. The first surgery implanting this type of customised 3-d-revealed cervical cage become completed in May 2015. A record of the complete task become posted in 2016 withinside the European Spine Journal as a technical innovation.
02. Computer-Aided Planning and Virtual Reality Simulation
Using a DICOM-CT data set (1.0 mm slice thickness), a 3D model of the patient’s cervical spine is rendered (“rendered anatomy of the cervical spine”; Figure 11.2). After analyzing the 3D model with a focus on deformities, each kyphosis is virtually corrected by repositioning the C6 and C7 vertebrae (‘repositioned anatomy’; Fig. 11.3). You are reading The Future of Cervical Spine Surgery .
the anatomic conditions with degeneration at C6–7 and slight kyphosis
With this procedure, the individualized cage reaches the ideal lordotic angle to restore the sagittal balance of the cervical spine. Osteophyte resection (“resected anatomy”; Figure 11.4) Resection of the posterior osteophytes is necessary to adequately decompress the spinal cord and nerve roots; Resection of anterior osteophytes should be considered if they obstruct access to the disc space, or particularly if there is symptomatic dysphagia. In order to check the accuracy of fit of the implant, the implantation can be simulated (“Implantation”; Fig. 11.5).
When determining the optimal implant height, the height and orientation of the facet joint in the adjacent planes must be taken into account. Planning begins with existing data for a standard EIT titanium cage, which is modified according to the patient’s individual anatomy. After the individual shaping of the patient end plates, the final implant height is determined (Fig.In the final phase, the entire virtual reality simulation and planning process is interactively modified and checked by the neurosurgeon, with this final step finalizing the final shape of the cage before going into production.
The credit of Images: Degenerative Diseases of The Cervical Spine
03. Manufacturing
EIT manufactures the porous titanium cage in layers using selective laser melting, a modern additive manufacturing process in which a very thin layer of titanium alloy powder, in this case TiAl6V4, is applied to a base plate. completely melted by a laser beam and forms a dense layer after consolidation. After this process, the base plate is lowered 30-50 µm and the next layer is applied. This process is repeated until all layers are complete and the cage reaches its end. Additionally, it is possible to mimic the trabecular structure of the bone within a titanium fusion cage.
This cage consists of EIT cell titanium with 80% porosity and a pore size of 0.65 mm and offers good conditions for secondary bone fusion without an additional synthetic bone graft (Fig. 11.7).The laser beam is guided by special 3D computer-aided design software that divides the device into several layers and calculates the laser tracks. Based on the patient’s special 3D data set, the precalculated 3D shape of the cage is precisely reproduced and shows the exact anatomy of the patient’s individual disc space (Figure 11.7). The Future of Cervical Spine Surgery.
04. Surgical Implantation
For ACDF with decompression, we use the standard anterolateral approach up to the C6-7 level of the cervical spine. First, the anterior osteophytes are virtually resected as planned, followed by discectomy and microsurgical decompression of the cervical spinal canal and foramina. Narrowing of the spinal canal and holes are selectively removed with a 4mm diameter drill or a 2mm diameter awl under the microscope, avoiding damage to the bony endplates of adjacent vertebral bodies to allow a perfect fit for the El The final step is the implantation of the Cages by intraoperative fluoroscopy.
A Caspar retractor is slightly distracted to implant the 3D-printed cage. In this way, after the distraction has been removed, the box finds its correct position thanks to its unique and perfectly adapted endplate design (Fig. 11.8). Also, for the same reason, it is impossible to move the cage in any direction with the introducer after distraction is complete.The pilot project of the first implantation of an individualized 3D-printed cervical cage resulted in a high precision of the implant fit (Fig. 11.8). It can therefore be assumed that an individualized cervical implant offers excellent primary stability. After removing the distractor and pins, the cage is checked intraoperatively by fluoroscopy. The perfect result is documented immediately postoperatively by anteroposterior and lateral x-rays (Fig. 11.9).
05. Perspective
In summary, we present the technical requirements for planning and manufacturing individualized 3D-printed cervical fusion cages based on patient-specific data. The implantation of these cages is as easy as the implantation of standard cages. When the improved loading area is able to reduce the implantation rate. Dislocation and subsidence of the cage should be evaluated in the future. Increased cooperation between spinal surgeons and industrial partners should develop cost-effective, individualized 3D-printed cages. However, the era of virtual reality in surgery and 3D printing in surgery has only just begun (Spetzger et al., 2013).
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