By Duncan Dillabough, iData Research
Traditional interbody devices replace the intervertebral disc of the spine while maintaining vertebral height and varying degrees of mobility within the patent. Devices are segmented by surgical access and interbody device material type. There are three major types of implants used: metal-based interbody implants, polyetheretherketone (PEEK) devices, and machined bone interbody devices.
Metal-based interbody implants are made from a base of titanium, which is then combined with a cone allograph to facilitate fusion. Titanium was introduced into the orthopedic view in the 1940s.1 Titanium is a suitable candidate for spinal implants as a result of the material’s biocompatibility and its ability to provide robust resistance against corrosion.1 In general, titanium interbody devices are considered stronger than those made of PEEK or bone.
PEEK began to be frequently used in the market starting in the late 1990s, and it grew in popularity as a result of its minimal radiographic interference, as well as its properties that make it more similar to bone, which has been linked to lower stress shielding, less bone remodeling, and decreased subsidence when compared to titanium.2,3 PEEK is also a hydrophobic polymer that does not allow for material integration into bone, which may cause cage migration and pseudoarthrosis.4
Machined bone interbody devices involve removing bone from a donor site, with the gold standard being iliac crest bone grafts (ICBGs).5 Patient dissatisfaction with machined bone, stemming from longer than average operating times compared to PEEK and metal interbody devices, the finite supply of iliac crest cone grafts, and the morbidity of the donor site, has led to a transition away from machined bone interbody devices.5
Metal interbody devices have continued to gain popularity within the Asia-Pacific traditional spinal implant market over recent years, and this trend will continue throughout the forecast period. Across the major segments of anterior lumbar interbody fusion (ALIF), posterior lumbar interbody fusion (PLIF), and transforaminal lumbar interbody fusion (TLIF), PEEK remains the dominant choice within the market. Metal device implants have gained popularity again, due in part to the properties of titanium compared to PEEK, which include its additional strength and biocompatibility.
Chart 1: Interbody Device Units Sold, Asia-Pacific, 2018-2028
Titanium continues to dominate the vertebral body replacement (VBR) and expandable interbody device markets; this has allowed the two interbody segments to increase their market share, as metal-based expandable and VBR devices will continue to represent the majority of the VBR and expandable interbody device segments.
On average across all interbody devices, PEEK devices are less expensive for medical institutions than their metal counterparts. However, the gap between metal and PEEK devices will continue to reduce as, on average, the price of metal interbody devices will continue to decline at a faster rate than that of PEEK interbody devices. A combination of factors will lead to the decline in the cost of metal devices, with a reduction in the manufacturing cost of titanium implants, increasing domestic manufacturing, and economies of scale all helping to reduce the gap in price between PEEK and metal interbody devices. The high price of titanium will limit price declines over the forecast period. While PEEK will remain lower in price on average over the forecast period, the reduction of the price gap combined with the material property advantages of titanium implants will increase demand for the product.
3D printing is the process of creating three-dimensional objects from a digital file. This involves a process of addition rather than the creation of 3D objects via subtraction (milling). The unique manufacturing process allows for the creation of more intricate designs and the use of less material than with subtractive creation.
In the case of a 3D printed interbody device, this can allow for the printing of a special microstructure for the contact surface between the vertebrae. The structure allows for the early fusion between vertebrae without the need for an autogenous bone filling cage.
Additive manufacturing also has the benefit of requiring less manufacturing space and fewer personnel than for the traditional means of manufacturing, so developments with 3D printing as a whole may lead to increased domestic manufacturing. In the future, manufacturers hope to eventually be able to supply custom implants for patients within the private market, which would provide interbody implants that will provide better stabilization between the vertebra and device than the current “off-the-shelf” interbody devices.6
While both PEEK and metal are suitable materials for additive manufacturing, titanium construction is favored within the current 3D printed interbody device market.
As a result of the COVID-19 pandemic supply shock, many Asian-Pacific countries have announced road maps intended to increase the local manufacturing of medical devices. The participation of local manufacturers in the metal interbody segment continues to rise in the market, as many countries look to create various policies that favor the domestic manufacturing of spinal implants over those offered by international competitors. As a result, many domestic manufacturers have expanded their spinal implant portfolios to include metal interbody devices. These trends are likely to continue over the forecast period as many governments look to become less dependant on international supply chains. The increase in competition within the metal interbody market will place further downward pressure on the average sale prices, while also providing a wider selection of offerings for healthcare facilities and their patients. The continuing increase in domestically produced products in the spinal implant space will create the ideal conditions for further expansion of the use of metal interbody devices within the Asia-Pacific markets.
Metal interbody devices will continue to gain popularity over PEEK and machined bone interbody devices. Metal interbody devices will benefit from both supply and demand related factors, as additive manufacturing, the reduction in the price gap between metal and PEEK devices, increased portfolio options from local manufacturers, and the high demand for titanium VBR and expandable devices will all contribute to increases in total device unit share.
Duncan Dillabough is a senior research analyst at iData Research. He develops, writes, and models syndicated research projects regarding the medical device industry, publishing both the Asia Pacific Spine and MIS series.
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