Improving Patient Outcomes in Spinal Surgery and the Role of 3D Printed Devices

SPECIAL REPORT

Improving Patient Outcomes in Spinal Surgery and the Role of 3D Printed Devices Fusion Through Design: A Look at CASCADIA™ 3D Interbody Systems Featuring Lamellar 3D Titanium Technology™ A Nagging Pain New Methods and New Technologies

Published by Global Business Media

SPECIAL REPORT

Improving Patient Outcomes in Spinal Surgery and the Role of 3D Printed Devices Fusion Through Design: A Look at CASCADIA™ 3D Interbody Systems Featuring Lamellar 3D Titanium Technology™

IMPROVING PATIENT OUTCOMES IN SPINAL SURGERY AND THE ROLE OF 3D PRINTED DEVICES

Contents

A Nagging Pain New Methods and New Technologies

Foreword

2

John Hancock, Editor

Fusion Through Design: A Look at CASCADIA™ 3D Interbody Systems Featuring Lamellar 3D Titanium Technology™ Published by Global Business Media

Published by Global Business Media Global Business Media Limited 62 The Street Ashtead Surrey KT21 1AT United Kingdom Switchboard: +44 (0)1737 850 939 Fax: +44 (0)1737 851 952 Email: info@globalbusinessmedia.org Website: www.globalbusinessmedia.org Publisher Kevin Bell

Anthony Troncale, PA, MHS, MBA* & Robert Lee^, BSc, MBBS, FRCS (Tr & Orth) *K2M Inc. 600 Hope Parkway SE, Leesburg, Virginia, USA ^Royal National Orthopaedic Hospital, Stanmore, UK

Background Fusion Through Design Lamellar 3D Titanium Technology Results to Date Case Study 1

Business Development Director Marie-Anne Brooks

Case Study 2

Editor John Hancock

A Nagging Pain

Senior Project Manager Steve Banks

John Hancock, Editor

Advertising Executives Michael McCarthy Abigail Coombes

Intervertebral Discs

Production Manager Paul Davies

New Methods and New Technologies

For further information visit: www.globalbusinessmedia.org

Camilla Slade, Staff Writer

The opinions and views expressed in the editorial content in this publication are those of the authors alone and do not necessarily represent the views of any organisation with which they may be associated.

Material in advertisements and promotional features may be considered to represent the views of the advertisers and promoters. The views and opinions expressed in this publication do not necessarily express the views of the Publishers or the Editor.

While every care has been taken in the preparation of this publication, neither the Publishers nor the Editor are responsible for such opinions and views or for any inaccuracies in the articles.

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Degenerative Disc Disease

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Surgery 3D Printing The Importance of Balance in Spinal Surgery The Importance of the Cage in Achieving Balance Looking to the Future

References 12

© 2018. The entire contents of this publication are protected by copyright. Full details are available from the Publishers. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical photocopying, recording or otherwise, without the prior permission of the copyright owner.

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IMPROVING PATIENT OUTCOMES IN SPINAL SURGERY AND THE ROLE OF 3D PRINTED DEVICES

Foreword

I

N 2016, more than 30 million working days were

with those devices and materials, and the potential for

lost in the UK to musculoskeletal problems,

negative outcomes, before continuing to introduce

including back pain and lower limb pain. That

the new technology that has begun to transform

was around 20% of working days lost in that year.

the treatment. This is 3D printing, which he explains

And the annual cost of lower back pain alone to

very clearly as to, not only the process but also the

the NHS has been put at c£500 million. There

additional opportunities that it has generated. In

is nothing minor about back pain, its causes or

particular, he looks at the application by K2M UK Ltd

its consequences. A significant proportion of

of Lamellar 3D Titanium Technology to develop a range

back problems result from Degenerative Disc

of CASCADIA Interbody Systems.

Disease (DDD), a condition that can be painfully

We also have an article on degenerative disc disease

debilitating but is manageable and treatable by

(DDD), what causes it, its symptoms, how it affects

a range of interventions including surgery. That

patients’ lives, its impact on healthcare systems and

often involves inserting a cage or spacer between

how it is usually managed and treated. Finally, there’s

vertebrae where the original intervertebral disc

an article by Camilla Slade based around the place of

has deteriorated and lost enough of its function to

surgery in the treatment of DDD with a further reference

warrant removal.

to 3D printing as well as the critical element of balance

This Report opens with an excellent article by

in spinal surgery.

Anthony Troncale which looks at how cages or spacers for use in spinal surgery have evolved over time and at the different materials that have been used. It also reviews some of the challenges and issues associated

John Hancock Editor

John Hancock, an Editor of Hospital Reports Europe, has worked in healthcare reporting and review for many years. A journalist for nearly 30 years, he has written and edited articles, papers and books on a range of medical and management topics. Subjects have included management of long-term conditions, elective and non-elective surgery, wound management, complex health issues, Schizophrenia, health risks of travel, local health management and NHS management.

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IMPROVING PATIENT OUTCOMES IN SPINAL SURGERY AND THE ROLE OF 3D PRINTED DEVICES

Fusion Through Design: A Look at CASCADIA™ 3D Interbody Systems Featuring Lamellar 3D Titanium Technology™ Anthony Troncale, PA, MHS, MBA* & Robert Lee^, BSc, MBBS, FRCS (Tr & Orth) *K2M Inc. 600 Hope Parkway SE, Leesburg, Virginia, USA ^Royal National Orthopaedic Hospital, Stanmore, UK

Lamellar 3D Titanium Background Degenerative disc disease (DDD) is a common condition that affects the whole population to a lesser or greater degree. As part of the natural ageing process, intervertebral discs degenerate and in the majority of cases are asymptomatic.

However, a significant proportion of the population present with symptoms including low back and cervical pain, arm and leg pain/weakness (due to nerve compression) or structural spinal deformities (scoliosis, spondylolisthesis, loss of lordosis/kyphosis or positive sagittal balance).

Patients can present with one or more of these symptoms. Surgery is required when conservative measures fail. In particular, fusion of specific vertebrae is required in cases of deformity and instability. Whilst it is possible to perform a posterior fusion with pedicle screws, there are significant advantages in removing the degenerate disc and using an implant (interbody spacer/cage) in the intervertebral space. The aim is to restore the intervertebral space to a more natural or anatomical position and, when necessary, provide an indirect decompression of the neural structures. Cages can be inserted either posteriorly, laterally, or anteriorly and the decision as to which approach is used is dependent on the pathology being treated and the patient’s anatomy.

It is essential to analyze a patient’s spinopelvic parameters prior to any fusion being performed in order to ensure that an iatrogenic flat back fusion deformity is not created. Failure to fuse a patient with adequate lordosis can lead to failure of the construct, pseudoarthrosis, and proximal level degeneration. Other factors which influence

the success of a fusion include patient factors such as smoking, steroid usage, osteoporosis, and other co-morbidities. Prior to any fusion, attempts are made to address modifiable risks of non-union. In addition, it is more difficult to achieve a fusion across multiple levels than just a single level.

To date, the most commonly used interbody spacer devices in spine were made of polyetheretherketone (PEEK). The advantage of PEEK over other interbody materials is its radiolucency and low elastic modulus. The radiolucent nature of PEEK facilitates fusion assessment on X-ray, and being non-metallic, allowed MRI assessment post-fusion should the need arise to assess the neural structures at the fused level. Furthermore, PEEK’s low modulus of elasticity, similar to that of cancellous bone, was felt to lessen the risk of subsidence. However, more recently PEEK has been shown to promote fibrosis and an inflammatory reactiona. OlivaresNavarrete et ala showed that cells were more mature on titanium than PEEK. Also, titanium had increased BMP levels compared to PEEK. Another study by the same groupb demonstrated that cells grown on PEEK expressed greater amounts of inflammatory cytokines that favour formation of fibrous tissue and that cells associated with PEEK had higher levels of factors associated with cell death/apoptosis.

Furthermore, clinically, PEEK cages have been associated with vertebral osteolysis resulting in a greater incidence of non-union.c Whilst titanium has more favourable biological properties, the elastic modulus and stiffness of solid titanium is much greater than cancellous

Technology uses an advanced 3D printing method to create structures that were once considered impractical with traditional manufacturing techniques

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IMPROVING PATIENT OUTCOMES IN SPINAL SURGERY AND THE ROLE OF 3D PRINTED DEVICES

bone (Figure 1) and subsidence has also been reported. As a result, the use of solid titanium cages has also resulted in some negative outcomes.

FIGURE 1: ELASTIC MODULUS OF INTERBODY MATERIALS SHOWING HIGHER ELASTIC MODULUS OF TITANIUM

Fusion Through Design

Whilst it is possible to perform a posterior fusion with pedicle screws, there are significant advantages in removing the degenerate disc and using an implant (interbody spacer/cage) in the intervertebral space

During the early 2010s, surgeons began expressing a desire for alternatives to PEEK interbody devices. The ideal interbody cage would be a less stiff implant which combined favourable biological and biomechanical properties.

K2M, Inc. recognized this need and in mid2012 launched an alternative material interbody project team. Rather than focus initially on a specific material type, the surgeon developers delved into the latest research in orthopaedic, dental, and material sciences literature. The surgeons focused on biomaterials that had osteoconductive and osteoinductive properties which promote bone ongrowth and ingrowth, both properties ideal for supporting bony fusion.

Based on research from the orthopaedic literature looking into porous coatings on orthopaedic devices, the development team found that 300–700 μm interconnected pores allowed for bony integration throughout an implant.d, e, f, g Furthermore, a material surface roughness of 0.5–20 μm led to greater osteoblastic activity and attachment than on smooth titanium and PEEK.h, i, j Unfortunately, devices manufactured using traditional subtractive manufacturing techniques, as with most metal alloy-based devices, require additional treatments and/or coatings to achieve these properties. The development team then turned their attention to the emerging field of 3D printing, first used in medical applications in 1999 k, l to develop Lamellar 3D Titanium Technology™.

Lamellar 3D Titanium Technology Lamellar 3D Titanium Technology uses an advanced 3D printing method to create structures that were once considered impractical with traditional manufacturing techniques. Starting with a titanium powder, the implants are grown through the selective application of a high-energy laser beam, allowing for the incorporation of both a porosity and surface roughness that pre-clinical data have associated with bone growth activity. Lamellar 3D Titanium Technology incorporates titanium with a surface roughness between 3–5 μm (designed to allow for direct bony ongrowth* j, m) and 500 μm longitudinal channels extending directly from endplate to endplate, which in conjunction with transverse windows, create an interconnected lattice designed to allow for bony integration. Titanium alloy was chosen as the material of choice given its favourable biological properties.

The first products designed using Lamellar 3D Titanium Technology were the CASCADIA™ Interbody Systems (Figure 2). The porosity inherent with Lamellar 3D Titanium Technology in conjunction with the proprietary CASCADIA product design, results in an approximately 70% porosity overall, and therefore a decreased radiographic signature. Thanks to an internal reversed hourglass design, the CASCADIA Interbody Systems allow for an average of 40% additional bone graft volume compared to the K2M PEEK equivalent.

Despite being made of titanium, CASCADIA’s stiffness is similar to PEEK and less than cortical bone and solid titanium alloy (Figure 3). The elastic modulus of PEEK is between the accepted values for cortical and cancellous bone, while that of titanium is significantly higher. It should be understood that the elastic modulus of a biomaterial is simply a material property that is independent of overall implant design. From stiffness testing, it can be demonstrated that CASCADIA interbodies behave similarly in compression to their PEEK equivalents. This is due to the design density of the CASCADIA interbodies. A simple analogy is that a solid block of titanium will behave differently from a titanium spring – it is the design which reduces the stiffness of the implant.

FIGURE 2: CASCADIA – SURFACE ROUGHNESS OF 3–5 μM & 500 μM LONGITUDINAL CHANNELS

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IMPROVING PATIENT OUTCOMES IN SPINAL SURGERY AND THE ROLE OF 3D PRINTED DEVICES

FIGURE 3: STIFFNESS OF LAMELLAR 3D TITANIUM IS SIMILAR TO PEEK & LESS THAN CORTICAL BONE

Initial laboratory studies show the enhanced integration between bone and Lamellar 3D Titanium compared to PEEK (Figure 4).

Results to Date CASCADIA Interbody Systems were cleared by the Food and Drug Administration in the United States and received the European CE Mark in 2015. K2M was the first leading spine company to market 3D-printed implants and has the most comprehensive portfolio of 3D-printed spinal implants (Figure 5). To date, over 30,000 Lamellar 3D Titanium Technology products have been implanted globally.

While results from a prospective, multi-center clinical study will be forthcoming, a number of smaller studies have demonstrated positive early results.

A study conducted by Mr Robert Lee (Consultant Spinal Surgeon) at the Royal National Orthopaedic Hospital NHS Trust, Stanmore, UK has demonstrated high fusion rates with the use of CASCADIA implants. The abstract, “Lumbar Interbody Fusion Rates In 3D Printed Lamellar Titanium Cages Using a Silicate Substituted Calcium Phosphate Bone Graft” was presented at the annual meeting of the British Association of Spine Surgeons, ISASS, Spine Society of Australia and Global Spine Congress in 2018.

This was a review of prospectively collected data from a single surgeon consecutive case series of 78 adult patients who underwent either transforaminal (TLIF) or lateral interbody fusions (LLIFs), using 3D-printed Lamellar titanium cages. All patients had posterior instrumentation or a lateral plate. All patients had CT scans at 12 months to assess fusion. The case mix included 25 single level TLIFs, 14 two-level TLIFs, 39 LLIF cases with 79 cages (12 patients had two cages inserted and 10 patients had three or more cages). CT scans showed solid fusion in all, bar one case with good integration of the cage at the vertebral body interface and no evidence of

During the early 2010s, surgeons began expressing a desire for alternatives to PEEK interbody devices. The ideal interbody cage would be a less stiff implant which combined favourable biological and biomechanical properties

FIGURE 4: HISTOLOGICAL SPECIMENS SHOWING BETTER INTEGRATION BETWEEN BONE & LAMELLAR 3D TITANIUM COMPARED TO PEEK

FIGURE 5: CASCADIA FAMILY OF IMPLANTS

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IMPROVING PATIENT OUTCOMES IN SPINAL SURGERY AND THE ROLE OF 3D PRINTED DEVICES

CASCADIA Interbody Systems were cleared by the Food and Drug Administration in the United States and received the European CE Mark in 2015

screw loosening. Average 12-month TLIF outcome scores were: VAS back 6.8 to 2.3, VAS leg 7.3 to 2, EQ-5D 0.338 to 0.889, EQ-5D VAS 51.8 to 78.4, ODI 55.4 to 25.4. Average 12-month LLIF outcome scores were: VAS back 7.2 to 2, VAS leg 7.8 to 1.5, EQ-5D 0.286 to 0.943, EQ5D VAS 44.0 to 82.3, ODI 57.1 to 18. The study demonstrated a 99% fusion rate at 12 months.

Another study by the same group (“Porous 3D Printed Lamellar Titanium Lateral Interbody Cages: Subsidence rates compared to PEEK and early clinical outcomes”), which was initially presented at Eurospine 2017, compared subsidence rates in two matched groups of 20 patients who underwent LLIFs – one group with PEEK and the other with CASCADIA implants.

Subsidence was 2.0 mm in the PEEK group.

There was no subsidence in any of the Lamellar titanium patients. ODI and EQ-5D VAS outcome scores at 6 months were better with Lamellar 3D Titanium Technology.

A similar study looking at subsidence rates in TLIFs was presented at Eurospine 2017 – “3D Porous Lamellar Titanium versus PEEK and Solid Titanium Interbody TLIF Cages: A Prospective Clinical and Radiographic Comparison”. There were three groups with 20 patients in each group: PEEK, solid titanium, and L3DTT. Subsidence was 2.3 mm in the PEEK group, 1.5 mm in the solid titanium group, and 0.6 mm in the Lamellar titanium group. This difference was significant.

Non-union occurred in three of the PEEK cases and in one solid titanium case. All the Lamellar titanium cases showed fusion at either six months or 12 months.

One further paper by Mr Robert Lee and Mr Lester Wilson, presented at IMAST 2017 (“In Vivo Analysis of Kambin’s Triangle and the Clinical and Radiographic Results Following the Use of 14mm Extra Wide 3D Porous Lamellar Titanium TLIF Cages”) reviewed the results of 80 patients who underwent TLIFs with 10 mm or 14 mm wide TLIF CASCADIA implants. Both groups showed excellent outcomes (VAS leg 1.5, VAS back 1.0, ODI 18, ED-5D 23.5, EQ-5D VAS 82.5).

EVEREST® Minimally Invasive (MI) Spinal System featuring SERENGETI® Retractor System (O-arm and Navigation), TERRA NOVA® Access System, 10 x 28 x 11 mm & 10 x 28 x 10 mm CASCADIA AN Oblique Cage

Case Study 1

Case Study 2

Patient information A 42 year-old female with L5/S1 grade 3 spondylolisthesis presented with severe right leg pain and back pain. The patient was unable to walk more than 50 metres, unable to sleep, and was essentially housebound.

Patient information A 72 year-old male with degenerative scoliosis with severe left L3/4 foraminal narrowing, presented with severe left thigh leg pain and back pain.

Operative treatment L4/5 and L5/S1 transforaminal lumbar interbody fusion with bilateral facectomies at L5/S1 and reduction of spondylolisthesis.

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Preoperative Imaging

X-ray, CT, and MRI – grade 3 spondylolisthesis L5/S1 with severe foraminal narrowing and mild retrolisthesis L4/5. High pelvic incidence and lumbar lordosis.

Inoperative Imaging

Postoperative Imaging

X-RAY - COMPLETE REDUCTION OF SPONDYLOLISTHESIS; CT AT 12 MONTHS – SOLID FUSION THROUGH CAGE.

Operative treatment L3/4 lateral interbody fusion with RAVINE® Lateral Access System and CASCADIA Lateral 3D Interbody (22 x 55 x 12 mm) and 14 mm CAYMAN® Minimally Invasive Plate System with 36 mm screws.

IMPROVING PATIENT OUTCOMES IN SPINAL SURGERY AND THE ROLE OF 3D PRINTED DEVICES

Preoperative Imaging

Post-Operative Imaging

POSTOPERATIVE X-RAY – L3/4 LATERAL INTERBODY CAGE WITH PLATE AND GOOD PRESERVATION OF PARAMETERS AND CORRECTION OF FOCAL SCOLIOSIS.

X-RAY, CT, & MRI – FOCAL DEGENERATIVE SCOLIOSIS AT L3/4, LEFT-SIDED FORAMINAL NARROWING

CT AT 12 MONTHS – SOLID FUSION THROUGH CAGE.

Future 3D printing holds great promise in healthcare. From 3D-printed organs, to prosthetics, to pills, researchers and engineers continue to explore alternative and unique uses for 3D printing as well as new materials with which to print advanced medical devices. Lamellar 3D Titanium Technology is just the first step in what will likely be a wave of innovation in better ways to address spinal disease and healthcare more broadly.

References: a. Olivares-Navarrete R, Hyzy SL, Slosar PJ, Schneider JM, Schwartz Z, Boyan BD. “Implant materials generate

different peri-implant inflammatory factors; poly-ether-ether-ketone promotes fibrosis and microtextured titanium promotes osteogenic factors.” Spine. 2015; 40(6): 399-404. b. Olivares-Navarrete R, Gittens RA, Schneider JM, Hyzy SL, Haithcock DA, Ullrich PF, Schwartz, Boyan BD. “Osteoblasts exhibit a more differentiated phenotype and increased bone morphogenetic protein production on titanium alloy substrates than on poly-ether-ether-ketone.” The Spine Journal 12 (2012): 265-272. c. Nemoto O, Asazuma T, Yato Y, Imabayashi H, Yasuoka H, Fujikawa A. “Comparison of fusion rates following transforaminal lumbar interbody using polyetheretherketone cages or titanium cages with transpedicular instrumentation.” European Spine Journal 2014 Oct; 23(10): 2150-5. d. Bobyn J. D., Pilliar R. M., Cameron H. U., and Weatherly G. C. “The Optimum Pore Size for the Fixation of Porous- Surfaced Metal Implants by the Ingrowth of Bone.” Clin. Orthop. Rel. Res., 150, (1980): 263-270. e. Gauthier O., Bouler J. M., Aguado E., Pilet P., and Daculsi G. “Macroporous Biphasic Calcium Phosphate Ceramics: Influence of Macropore Diameter and Macroporosity Percentage on Bone Ingrowth.” Biomat., 19 (1998): 133-139.

A study conducted by Mr Robert Lee (Consultant Spinal Surgeon) at the Royal National Orthopaedic Hospital NHS Trust, Stanmore, UK has demonstrated high fusion rates with the use of CASCADIA implants

f. Karageorgiou V. and Kaplan D. “Porosity of 3D Biomaterial Scaffolds and Osteogenesis.” Biomat., 26, (2005): 5474-5491. g. Predecki P., Stephan J. E., Auslaender B. A., Mooney V. L., and Kirkland K. “Kinetics of Bone Growth into Cylindrical Channels in Aluminum Oxide and Titanium.” J. Biomed. Mater. Res., 6, (1972): 375-400. h. Boyan B. D., Batzer R., Kieswetter K., Liu Y., Cochran D. L., Szmuckler-Moncler S., Dean D. D., and Schwartz Z. “Titanium surface roughness alters responsiveness of MG63 osteoblast-like cells to 1 alpha,25-(OH)2D3.”

J. Biomed. Mater. Res., 39, (1998): 77-85. i. Lincks J., Boyan B. D., Blanchard C. R., Lohmann C. H., Liu Y., Cochran D. L., Dean D. D., and Schwartz Z. “Response of MG63 Osteoblast-like Cells to Titanium and Titanium Alloy is Dependent on Surface Roughness and Composition.” Biomat., 19, (1998): 2219-2232. j. Martin J. Y., Schwarts Z., Hummert T. W., Schraub D. M., Simpson J., Lankford, Jr. J., Dean D. D., Cochran D. L., and Boyan B. D. “Effect of titanium surface roughness on proliferation, differentiation, and protein synthesis of human osteoblast-like cells (MG63).” J. Biomed. Mater. Res., 29, (1995): 389-401. k. Ventola, C. “Medical applications for 3D printing: current and projected uses.” Pharmacy & Therapeutics. v39(10): 2014 Oct. l. Whitaker, M. “The history of 3D printing in healthcare.” Bulletin. v96(7): July 2014. m. Nishimura, N., Kawai, T. “Effect of microstructure of titanium surface on the behavior of osteogenic cell line MC3T3-E1.” Journal of Materials Science: Materials in Medicine, 9, (1998): 99-102. *Based on pre-clinical data. May not represent clinical results.

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A Nagging Pain John Hancock, Editor Back pain is often the subject of jokes until someone suffers with it; then it’s not funny.

T

A vertebral disc is the shock-absorbing structure between each vertebra. The disc has a thick outer layer (annulus) that surrounds the soft gel-like center (nucleus). Intervertebral discs act as cushions in between vertebrae

HE SPINE is an amazing piece of natural engineering, the central core to which all components of our bodies are linked.

It’s so important that animals are classified according to whether they have a backbone - vertebrates, or not - invertebrates. And, in man, the structure is most important as, by supporting an upright stance, it makes us into biped as opposed to quadruped animals. The spine works hard throughout our lives and is constructed to deal with a lot of wear and tear.

Intervertebral Discs The spinal column consists of a number of vertebrae separated by intervertebral discs (commonly simply called ‘discs’) which play a very important part in the function of the backbone. Spine-health1 tells us that, “A vertebral disc is the shock-absorbing structure between each vertebra. The disc has a thick outer layer (annulus) that surrounds the soft gel-like center (nucleus). Intervertebral discs act as cushions in between vertebrae. The spinal canal, containing the spinal nerves, lies directly behind the disc and the vertebral bodies.”

Making up a quarter of the spine, each disc allows a little movement between its adjoining vertebrae which creates a reasonable level of flexibility along the length of the spine. However, with that flexibility and the natural pressure generated by its function, parts of the spine do wear with age and the softer intervertebral discs are particularly susceptible to a condition called Degenerative Disc Disease (DDD).

Degenerative Disc Disease Inasmuch as it is neither degenerative nor a disease, DDD is a misnomer but what it describes is a condition that, as The Spinal Foundation2 explains, “results from ageing and its effects vary considerably in their nature and severity and should be referred to as disc degeneration (Spondylosis). However, the term Degenerative Disc Disease is generally used to define a number of natural processes and conditions brought about by the general ageing and wear and tear upon the spinal discs and the secondary effects 8 |WWW.HOSPITALREPORTS.EU

that this has upon associated spinal structures.”

More specifically, ‘back-ache’ or low back pain (LBP) “…is the top global cause of years lived with disability.” Is the introduction to a BMJ Open article3 which continues to explain in relation to non-specific LBP (NSLBP), “Lumbar degenerative disc disease (LDDD) is a condition which has been found to be significantly associated… with NSLBP, the lifetime prevalence of which may be as much as 80% with an annual prevalence rate of 25–60%.”

On prevalence, Hebrew Senior Life Institute for Aging Research4 reported in Science Daily that “…one-third of people 40-59 years have image-based evidence of moderate to severe degenerative disc disease and more than half had moderate to severe spinal osteoarthritis. Beyond that, the prevalence of disc height narrowing and joint osteoarthritis increased 2 to 4 fold in those aged 60-69 and 70-89 respectively. Furthermore, scientists observed that progression of these conditions occurred 40 – 70% more frequently in women than men.”

Causes The causes of DDD are wear and tear of the intervertebral discs, especially in the lower back and neck and this is associated with or progressive with aging. The Arthritis Foundation5 sets out several factors that might cause a disc to lose its integrity: “The drying out of the disc. As we age, the disc dries out and doesn’t absorb shocks as well. Daily activities and sports can cause tears in the outer core of the disc. Injuries can cause swelling, soreness and instability” Because there is little blood supply to discs, once one is injured, there is little chance that it will repair and more chance that it will deteriorate.

Symptoms The symptoms are, of course, what make most people aware that there is a problem. The Arthritis Foundation lists a number of symptoms within the article above, and the Mayfield Clinic6 sums them up as, “… pain that starts gradually and gets progressively worse.” The pain might manifest in the back or in the legs and will vary between a

IMPROVING PATIENT OUTCOMES IN SPINAL SURGERY AND THE ROLE OF 3D PRINTED DEVICES

nagging background pain and intense pain from time to time. Sitting, standing still, twisting or bending is often when the pain is worse, because that’s when the spine is under most pressure, while walking will often reduce the pain.

Impact on patient lives Perhaps not surprisingly, the impact on lives of people with DDD will vary according to the stage and intensity of their condition. Reassuringly, as Know Your Back7 explains, “you cannot die from degenerative disc disease. This can, however, be a quality of life issue.” Some elements of modern life such as air travel, packing a suitcase or even brushing your teeth can mean sitting or standing in a way that exacerbates the pain. On the plus side, pain often subsides with normal movement or after a few days but incidents of pain can become more frequent and there is no cure for DDD, nor is the condition reversible. Also, depending on the type of job that a patient does, DDD can either curtail or prevent work and, in some occupations, it might be dangerous to continue working. Disability Benefits Help8 offers guidance on this. Pain killers as well as cessation of smoking, weight reduction

and exercise of the right type can help to manage the pain. Spine-health9 outlines some key actions in a self-care program that DDD sufferers can use.

• First, quickly reduce the pain to a tolerable level; • Engage in a controlled, progressive exercise and active rehabilitation; • Identify and act on any behavioral and activity modifications needed to minimize aggravation to the disc; • Improve hydration and nutrition to foster improved spinal disc health.

You cannot die from degenerative disc disease. This can, however, be a quality of life issue

Impact of healthcare systems Any regime such as that mentioned above will help patients to ease pain and it will also help to ease pressure on healthcare systems such as NHS England, which has developed a National Back Pain Pathway10 in 2016 in face of the fact that, “Back pain is the largest single cause of disability in the UK, with lower back pain alone accounting for 11% of the total disability of the UK population.”

That’s the problem: next, what can be done about it?

Back pain is the largest single cause of disability in the UK, with lower back pain alone accounting for 11% of the total disability of the UK population

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New Methods and New Technologies Camilla Slade, Staff Writer 3D printing has made it easier to make a key component in surgery to correct Degenerative Disc Disease

A

LBEIT THAT Degenerative Disc Disease (DDD) and other complex spinal conditions can be explained, what will be of more interest to patients and clinicians will be how they might be treated.

3D printing, which creates a physical object from a digital design, first came into its own as a means of rapidly making a prototype or concept model

Surgery The previous article sets out a number of management techniques and publications such as Medical News Today11 which offer a range of things to do for patients and clinicians including, as the Cleveland Clinic12 explains, “If pain persists despite medical treatment, your doctor may recommend surgery.” One such surgical treatment for a severe degenerative back condition is spinal fusion which, Cleveland Clinic again, “involves joining the bones together with screws or bone grafts to provide stability.” This can be achieved either using bone taken from another part of the body or with metal implants to hold the vertebrae together while new bone grows between them.

Using a cage to separate vertebrae One method used involves the removal of the degenerate disc and the placing of a cage between the vertebrae which can achieve the separation necessary, and it is in this area that the relatively new technology of 3D printing (sometimes known as additive manufacturing) offers a reasonably costed method of tailormaking a cage for each specific patient’s requirements.

3D Printing 3D printing, which creates a physical object from a digital design, first came into its own as a means of rapidly making a prototype or concept model without the old-world need for a craftsman to translate design into material or the need to use several components to achieve the desired shape. In 3D printing, layers of material are applied and built up to create a 3D object.

One advantage is that, unlike production line or conventional manufacture, 3D printing allows 10 |WWW.HOSPITALREPORTS.EU

rapid changes in the configuration of the object being produced by simply re-configuring the design program. As 3D HUBS13 explains; “Complex designs can be uploaded from a CAD model and printed in a few hours.” The system also offers single step manufacture and usually lower costs because it reduces material waste to near zero, requires less skilled labor to operate and it’s faster than traditional handbuilding of a part. 3D printed parts and devices are gaining ground across the healthcare sector in areas such as cardiology and heart surgery. They are providing organ models for training or familiarization purposes and even being used to print living tissue. As Scitech Europa14 put it, “The outlook for medical uses of 3D printing is evolving at an extremely quick pace as specialists are beginning to utilize the technology in more advanced ways. Patients are now experiencing improved quality of care through 3D printed implants and prosthetics…”

The Importance of Balance in Spinal Surgery The Science Direct article ‘Neurological risks in scheduled spinal surgery’15 opens with the comment, “Spinal surgery is a high-risk specialty with an ever-increasing patient volume. Results are very largely favorable, but neurologic damage, the most severe complication, may leave major sequelae [conditions resulting from a previous injury], some of which can be life-threatening.” In particular, the article emphasizes the importance of patient positioning to the success of spinal surgery stating that “All possible compression and stretching points along the nerve trunks of the four limbs and brachial plexus should be checked [for balance]” Achieving balance So important is balance that the 2018 Meeting of Minds conference for spine surgeons focused on the need for spinal balance during surgery and how to achieve that using Total

IMPROVING PATIENT OUTCOMES IN SPINAL SURGERY AND THE ROLE OF 3D PRINTED DEVICES

The outlook for medical Body Balance™; “achieving balance of the spine by addressing each anatomical vertebral segment with a 360-degree approach of the axial, coronal, and sagittal planes, emphasizing Total Body Balance as an important component of surgical success.” This is not new. As the World Journal of Orthopedics ‘Importance of balance and profile in adult spinal reconstruction’16 opened, “Long before its current understanding, the concept of balance was common among spine surgeons dealing with deformities, but it was a hard one to transfer to clinical practice. Thanks to the pioneering work of Duval-Beaupere and followers, the idea of balancing the sagittal contour of the spine has gained scientific status and is now in the armamentarium of the skilled surgeon as the single most important tool to achieve superior clinical results in adult spinal deformity surgery.”

The paper continues to set out some methods, gleaned from a number of papers, to achieve postoperative balance.

Not so much a clinical as a psychological reason for balance was set out in ‘Risk Factors for Postoperative Coronal Balance in Adult Spinal Deformity Surgery’17 as reported in Sage Journal. “Coronally balanced patients had higher Scoliosis Research Society (SRS) self-image scores at their initial follow up after surgery compared to the imbalanced patients.”

Self-image often suffers if a patient has, say, a stoop with DDD: if that can be removed, their self-image will improve.

The Importance of the Cage in Achieving Balance Balance and alignment matter, which means that any cage placed between vertebrae for the purpose of separating them should also contribute to balance and alignment and that will be more easily achieved if the cage is tailored exactly to the patient’s and the site’s contours.

3D printing makes that much easier and faster to achieve.

One such solution is the innosurge CAPRI® Cervical 3D Expandable Corpectomy Cage System which provides a 3D-printed solution for stabilization of the spine in cases of vertebral body resections and is constructed using 3D printing with Titanium. This system allows for in-situ height expansion and endplate angulation to achieve spinal balance and incorporates, as reported in Orthopaedic List18, “… complex internal geometries and rough surface architecture that pre-clinical data have associated with bone growth activity.”

uses of 3D printing is evolving at an extremely quick pace as specialists are beginning to utilize the technology in more advanced ways. Patients are now experiencing improved quality of care through 3D printed implants and prosthetics

Looking to the Future Spine Universe19 reports on a bright future in this field, including the addition of artificial discs to the surgeon’s toolbox. Advances in Orthopedics ‘Lumbar Degenerative Disc Disease: Current and Future Concepts of Diagnosis and Management’20 concludes, “While current strategies aim to remove the pain generator through surgery, future, emerging modalities aim to reverse the degenerative cascade through the use of biologics and gene modification.” Pending that, 3D printing will enable a great deal better solutions today.

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IMPROVING PATIENT OUTCOMES IN SPINAL SURGERY AND THE ROLE OF 3D PRINTED DEVICES

References: Spine Health www.spine-health.com/glossary/intervertebral-disc

1

2

The Spinal Foundation www.spinal-foundation.org/conditions/degenerative-disc-disease-or-disc-degeneration-spondylosis

3

https://bmjopen.bmj.com/content/6/9/e011075

4

Science Daily www.sciencedaily.com/releases/2018/05/180517163317.htm

5

Arthritis Foundation www.arthritis.org/about-arthritis/types/degenerative-disc-disease/

6

Mayfield Brain & Spine http://www.mayfieldclinic.com/pe-ddd.htm

7

Know your back www.spine.org/KnowYourBack/Conditions/DegenerativeConditions/LumbarDegenerativeDiscDisease

8

Disability Benefits Help www.disability-benefits-help.org/working-ability/degenerative-disc-disease

9

Spine Health www.spine-health.com/conditions/degenerative-disc-disease/living-degenerative-disc-disease

10

NHS England www.england.nhs.uk/blog/charles-greenough/

11

Medical News Today www.medicalnewstoday.com/articles/266630.php

12

Cleveland Clinic https://my.clevelandclinic.org/health/diseases/16912-degenerative-back-conditions#3

13

3D Hubs www.3dhubs.com/knowledge-base/advantages-3d-printing

14

Scitech Europa www.scitecheuropa.eu/using-3d-printing-healthcare/87437/

15

Science Direct www.sciencedirect.com/science/article/pii/S1877056813002570

16

US National Library of Medicine, ‘Importance of balance and profile in adult spinal reconstruction’ www.ncbi.nlm.nih.gov/pmc/articles/PMC4458491/

17

Sage Journals https://journals.sagepub.com/doi/full/10.1177/2192568218764904

18

Orthopaedic List www.orthopaediclist.com/product/1801071-Capri.html

19

Spine Universe www.spineuniverse.com/treatments/emerging/artificial-discs/artificial-discs-future-bright

20

Advances in Orthopedics www.ncbi.nlm.nih.gov/pmc/articles/PMC3335178/

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