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Bone Benefits of 3D Printing

24 Mar

Recently there has been some extraordinarily interesting articles in the press on the value of 3D printing in surgical procedures.  In particular the United Kingdom seems to be leading the way in producing and using 3D printed implants for use in reconstructive surgeries, as recent articles in the BBC, the Daily Telegraph and The Independent publications highlight.

Mr Craig Gerrand, a consultant orthopaedic surgeon in an NHS hospital in Newcastle-Upon-Tyne, England, recently announced the success of producing and fitting half of a 3D printed titanium hip into an unnamed patient who was suffering from chondrosarcoma.  Chondrosarcoma is a cancer of the cartilage cells and typically tends to affect the axial skeleton.  In this case the unnamed patient suffered severe damage to one half of his hip due to the effect of the destructive cancer.  In an effort to stop the spread of the cancer, which rarely responds to radiotherapy or chemotherapy, the surgeon was forced to remove half of the patient’s hip (termed an hemipelvectomy, which can be external or internal dependent on if the leg is to be amputated as well).

Before this, however, Mr Gerrand was able to construct and print a 3D titanium half model of the patient’s  hip which, along with the added attachment of a hip socket replacement, he was then able to implant into the patient following the removal of the chondrosarcoma affected bone.  The fake hip was based on scans and x-rays of the patient’s own hip for anatomical reasons and was fully produced using a 3D printer.  The printer used lasers to fuse together titanium powder, which slowly built up a model of the hip layer by layer.  The fake hip was then coated in a mineral into which the remaining bone in the patient’s healthy hip could fuse with, providing long-term stability during recovery and mobility.  Although the news articles on the case were only recently produced, the actual surgery itself was carried out over 3 years ago.  Wonderfully the patient continues to manage to walk with mobility aids, something that would be unthinkable if the surgeon had not been able to print and implant the titanium hip.

In other news recently, as reported by the BBC, the Welsh victim of a vicious motorcycle accident was able to benefit from the 3D printing of custom parts for use in maxillofacial reconstruction.  The use of 3D printing was used at each stage of the procedure, including the planning of the surgery and the reconstruction itself, by using titanium parts to stabilise or replace parts of the patient’s own facial bones.

Following the motorcycle accident, which severely damaged both of the patient’s zygomatic bones as well as sustaining damage to the maxilla, frontal and nasal bones, the patient’s face was reconstructed in a series of operations.  To achieve the aim of improving the patient’s face to almost pre-accident standards the surgeons scanned the skull of the individual using a CT scanner and printed the results using a 3D printer, the results of which helped to produce a symmetrical model of his skull to help plan the surgery in detail.  By using cutting guides and by being able to measure the facial skeletal anatomy directly, they managed to print titanium plates to match the symmetry of the patient’s face originally, and likely minimised the time the patient spent under anesthetic.  In the article the patient, from the city of Cardiff in Wales, movingly states how he now looks as he did before the motorcycle accident, adding that he was able to go out in public once again following the reconstructive surgery.


A model example of how the surgeons helped plan the surgery to improve the motorcycle accident man’s face with 3D printed titanium implants. The image shows the left zygomatic arch with the titanium implants in white against the model of the cranium. (Image credit: The BBC 2014).

The two innovative procedures above are fine examples of the value of integrating the latest technology into the operating theatre, but they also highlight some themes of the body and surgical intervention that interest me.  The benefits of being able to 3D print specific and specially made parts offer a ‘continuation’ for the patient of their own bodies, even with the distinct disconnect (and often intrusive procedures) between the effect of the trauma or disease process and the reconstructive attempts at re-structuring the body, as highlighted in the above orthopaedic cases.

3D printing is a fast-moving technology in the medical world, where even the possibility of being able to bioprint human organs and tissue is fast becoming a possibility for the future.  Perhaps most significantly it offers the option for the patient to use their own bodies (or, more specifically, their cells) to help cultivate a ‘second chance’ organ or tissue in the lab using artificial scaffolds to grow the tissue needed.  To a small degree this has already been carried out with certain tissues, but further work is needed to be able to bioprint human organs properly.  But back to the use of 3D printing in orthopaedic surgery.

Reconstructive orthopaedic surgery generally aims to improve the quality of life for the individual through physical manipulation and internal or external fixation of an implant onto, or into, the bone directly.  The benefits of this are not just anatomical but often also psychological, perhaps more so in maxillofacial procedures.  The patient may feel that their appearance has improved dramatically, or that they have been made to look more normal.  This can increase the positive social perception of the patient themselves and boost self-confidence.  Of course there are always risks associated with reconstructive orthopaedic surgery, the first and foremost being the fact that more damage may occur as a result of the often intrusive procedures, particularly the risk of implant fatigue and possibility of macro/micro fracture of surrounding bone material.

Internal and external fixations also often run the risk of infection, more so when there is the risk of repeated surgical interventions.  Internal fixation (such as intramedullary rodding) has the possibility of deep bone infection, whilst external fixation (such as the use of the Ilizarov frame) often results in small localised infections.  Nevertheless the risk of infection by implant is often controlled for by using clean surgical rooms, sterilised medical equipment and the infusion of antibiotics during and post-surgery.  Further to this, antibiotic laden cement is also often used during the surgical fixation of an implant as an added protector against infection through the introduction of foreign bodies.

I am also interested in the after effects of surgery in the perception of the self.  Titanium implant parts are typically manufactured for general use, although there is a dizzying variety of screws, plates and rods available to the orthopaedic surgeon.   Of course they are also shaped and made to fit the patient to a certain degree.  Titanium is a fairly hefty metal, with the patient often being able to tell that something heavy has been implanted into the body upon awakening from surgery.  It also often hammered or screwed into the bone, sometimes causing the bone to fracture or microfracture during the process, or afterwards as the patient starts to weightbear.  (As a side note orthopaedic surgeons are often built like rugby players because of the demanding physical aspect of orthopaedic surgery).

The new generation of 3D printed parts are often made of different materials than purely consisting of titanium.  Importantly there is the option to help improve the post surgical integration of existing bone and ceramic implants (such as hip replacements, which often use ceramic femoral heads) through the ability to print intricate designs to help meld with bone, and the ability to seed the ceramic scaffolds with the patients own cultured cells to promote  healthy bone growth (Seitz et al. 2005).  This is purely speculation and conjecture, but I wonder if the newer materials used, are of a much lighter material than titanium and are, as a result, less intrusive to the person undergoing the surgery?

What the 3D printing of implants offer is the opportunity to make identical and specifically made models of the  patient for their own use (Fedorovich et al. 2011), by either basing the custom build on an existing bone of the patient or by specifically making a part to improve what has either been lost to a disease process or a traumatic incident, to name the two main causes for orthopaedic reconstructive surgery.  There are also opportunities to help promote wound healing and prevent infection during and post-surgery (Lee et al. 2012), a step that is needed considering the rise of drug resistant germs, the general decline in pharmaceutical companies producing new antibiotics, and the widespread misuse of antibiotics in general (Mayo Clinic release).  3D printing then, I believe, is an important step in advancing and improving the techniques, approaches and materials used in orthopaedic surgery.

Learn More

  • Watch Ben Garrod’s Secrets of Bones BBC TV series to learn more about just how wonderful the skeleton is.  Learn more about the remarkable 3D print of his skull here.
  • Kristina Killgrove, over at Powered by Osteons, has a series of posts on her attempts to integrate 3D printing with teaching human osteology, check it out here.
  • The frankly amazing news of the Netherlands surgeons who were able to produce a 3D model of a patient’s cranium which was then successfully implanted can be found here, although there has been a lack of evidence for this procedure in other mainstream or medical publications.


Fedorovich, N. E., Alblas, J., Hennink, W. E., Oner, F. C. & Dhert, W. J. A. 2011. Organ Printing: The Future of Bone Regeneration? Trends in Biotechnology29 (12): 601-606.

Lee, J-H., Gu, Y. Wang, H. & Lee, W. Y. 2012. Microfluidic 3D Bone Tissue model for High-Throughput Evaluation of Wound-Healing and Infection-Preventing Biomaterials. Biomaterials. 33 (4): 999-1006.

Seitz, H., Rieder, W., Irsen, S., Leukers, B. & Tille, C. 2005. Three-Dimensional Printing of Porous Ceramic Scaffolds for Bone Tissue Engineering. Journal of Biomedical Materials Research Part B: Applied Biomaterials. 74B (2): 782-788.

Skeletal Series Part 3: The Human Skull

22 Apr

In this post I will be discussing the basics of the human skull; its anatomical features, number of elements, terminology, key functions and how to handle a skull.  Alongside the earlier blog on variations in human skeleton and the ethics that should be considered, this should prepare the user for interaction and identification of physical remains.

A skull in situ. From the Gadot archaeological site in Israel.

Individual elements found in the human skull, individual elements discussed below (Pearson Education 2000).

 The human skull is one of the most complex structures in the human skeleton.  It houses the foundations for the sense of smell, sight, taste & hearing, alongside the housing of the brain.  It also provides the framework for the first processes of digestion by mastication of food with the use of the teeth anchored in mandible and maxilla bones (White & Folkens 2005: 75).  White & Folkens (2005) go on to note that it is of value that the key anatomical landmarks of the skull are noted.  These include the Orbits of the eye sockets, the Anterior Nasal Aperture (nose hole), External Auditory Meati (ear canals), the Zygomatic Arches (cheek bones) along with the Foramen Magnum (base of the skull).  It is by these landmarks that we can orientate the skeletal elements if they are disarticulated or have been broken (White & Folkens 2005: 75).


Particular care should be taken when excavating the skull, or any human skeletal element.  Careful consideration should be made of its location, burial type, any nearby skeletons, and of course any different stratigraphic (colour/cut/fill) features present should be noted (Mays 1999).  As this is the only chance to lift the skeleton since deposition, careful notes should be made on first impression and any post depositional changes that can be immediately identified.  Careful sieving of the soil matrix around the skull should take place, to help retain any small fragments of bone or lose teeth (whole and partial fragments) (Mays 1999).  Differential preservation, dependent on deposition & burial environment conditions, will mean that it is likely sections of the skull will not survive.  These are often the small, delicate bones located inside the cranial-facial portion of the skull.  The likeliest to survive portions are the mandible and the cranial plate elements because of their tough biological nature.


When handling the skull it should be noted of the above major landmarks.  For example, you will not damage the skull whilst carefully holding it in both your hands but if you hold it by the orbits you are liable to damage the surrounding bone.  The foramen magnum is usually stable and strong it to withstand creeping fingers as a hold place.  Whilst studying the skull on a desk, a padded surface should be provided for it to rest upon.  Care should be taken when handling the mandible, and temptation should be resisted in testing the mechanical properties of the surrounding bone (Mays 1999).

Anatomical Planes

For use between comparative material, it is useful to use a standardized set of viewing planes.  The human skull is often viewed via the Frankfurt Horizontal (White & Folkens 2005).  The FH is a plane of three osteometric points conceived in 1884 (see above link).  The skull is normally viewed from six standard perspectives.  These include norma verticalis (viewed from above), norma lateralis (viewed from either side), norma occipitalis (viewed from behind), norma basilaris (viewed from underneath) and norma frontalis (viewed from the front). Thus, when considered with osteometric points, measurements can be taken and compared and contrasted (White & Folkens 2005: 86).

Cranial Terminology and Elements

  1. The Skull refers to the entire framework including the lower jaw.
  2. The Mandible is the lower jaw.
  3. The Cranium is the skull without the mandible.
  4. The Calvaria is the cranium without the face portion.
  5. The Calotte is the calvaria without the base of the skull.
  6. The Splanchnocranium is the facial skeleton.
  7. The Neurocranium is the braincase.

The skull in infants is made up of 45 separate elements but as an adult it is normally made up of 28 elements (including the ear ossicles) (White & Folkens 2005: 77).  The Hyoid bone (the ‘voice box’ bone) is generally not included in the count of skull bones.  The identification of the elements can be made hard as idiosyncratic differences, and fusion between plates of the cranium, can lead to differences.  A number of elements in the human skull are paired elements; simply that they are part of two identical bones in the skull.  Alongside this there are also separate elements.  The list is below-

Paired Elements

  1.  Parietal bones- Located form the side and roof of the cranial vault.
  2. Temporal bones- Located laterally and house the Exterior and Interior Auditory Meatus.  They also include the Temporomandibular Joint (TMJ for short), the
  3. Auditory Ossicles– The malleus, incus and stapes (6 bones altogether) are located in both of the ears, very near the temporal bones (Very often never recovered in archaeological samples).
  4. Maxillae bones- Located proximal to the mandile, houses the upper jaw.
  5. Palatine bones- Located inside the mouth and forms the hard palate and part of the nasal cavity.
  6. Inferior Nasal Conchae bones- Located laterally inside the nasal cavity.
  7. Lacrimal bones- Located medially in the orbits.
  8. Nasal bones- Located distally to the frontal bone, helping to form the upper nose.
  9. Zygomatic bones- They are the cheekbones.

‘Norma Lateralis’ view of the human skull (Pearson Education 2000).

Single Elements

  1. Frontal bone- Located anterior, it is the brow of the skull.
  2. Occipital bone- Located to the rear of the skull, houses the Foramen Magnum.
  3. Vomer bone- Located in the splanchnocranium, and divides the nasal cavity.
  4. Ethmoid bone- A light and spongy bone located between the orbits.
  5. Sphenoid bone- Located inside the front of the splanchnocranium, a very complex bone.
  6. Mandible bone- The lower jaw.

‘Norma Frontalis’ view of the human skull, note the large orbits (Pearson Education 2000).

‘Norma Basilaris’ view of the human skull, note the foramen magnum where the spinal chord enters the skulls to connect with the brain (Pearson Education 2000).

‘Intracranial Superior’ view of the human skull, again note the foramen magnum where the spinal chord enters the skull to join the brain and the thickness of the outer and inner cortical bones of the skull (Pearson Education 2000).

General Discussion

The human skull is a complex part of the body.  It is key in identification of sex by the size of the Mastoid Process, Supraorbital Torus, tooth size, and the squareness of the mandible amongst others; it can also be used in describing age at death by tooth wear, Cranial Suture closure and general porosity of the bone (Roberts & Manchester 2010, White & Folkens 2005, Jurmain et al 2011).  A later post will detail exactly how in further detail.

It has also changed as our species, Homo Sapiens, evolved from earlier hominids.  The morphology of the human skull has certainly become more gracile, and as an indicator and outcome of the agricultural revolution, it seems our mandibular size and muscle robusticity has slowly become less pronounced (Larsen 1999: 230, Jurmain et al 2011).  As Larsen remarks (1999: 226), it is the influence of environment and mechanical behaviour that helps determine the morphology of the skull, alongside considered genetic factors.  It is important we keep this in mind as we look at archaeological material.  Studying population trends in both temporal, cultural and geographic contexts can have important results and can also highlight long term trends.

One such trend is the discussion that a change to a more ‘globular cranial change in the Holocene represents a compensatory response to decrease in functional demands as foods become softer’ (Larsen 1999: 268).  This is underscored in archaeological populations worldwide that consumed abrasive foods with populations that consumed non abrasive foods.  By being affected by food production processes & the nature of the food itself, the morphology of the cranial facial biomechanics has changed to adjust to differing food sources.  This change has influenced cranio-facial size and morphology, occlusal abnormalities, tooth size, dental trauma, and gross wear from masticatory and non-masticatory functions (Larsen 1999: 269, Waldron 2009).

Case Study: A Mesolithic-Neolithic population trend in Ancient Japan

One example of the importance of cranial studies, and of the skull in general in archaeology, is the discussion of population change during the end of the Jomon period of Japan.  Lasting roughly from 14,000 BC to 300 BC, the Jomon culture has evidence for the earliest use of pottery in the world, and made extensive use of the large variety of environments in the Japanese archipelago (Mithen 2003).  This culture has been classed as largely hunter-gather-forager in lifestyle, until roughly the Yayoi period around 300 BC; when the adoption to agriculture was fully implemented with intensive rice agriculture, weaving and the introduction of metallurgy (Mays 1998: 90).

The evidence suggests that the Yayoi were settlers from mainland Asia, with the evidence from craniometric studies and dental studies of both Jomon and Yayoi populations, alongside a comparative study with the modern day aboriginal Ainu people who inhabit the island of Hakkaido, north of mainland Japan.  The Ainu population themselves maintain that they are the descendents of the Jomon people, and with the skeletal data of skull morphology in the modern population compared to the Jomon archaeological data set, the evidence seems to match (Mays 1998: 92).  Population pressures during the end of the Jomon period and movement of the Jomon culture is therefore suggested as a geographic movement.  The skeletal data from the modern day Ainu population, concentrated in Hokkaido, provide evidence of a Jomon movement north due to pressure, as mainland Japanese modern population cranial measurements shows a mix of origin (Mays 1998: 90).

The importance of this work highlights the movement of the adaptation of agriculture in a relatively late time frame, in comparison to mainland Asia and Europe.  The palaeoenvironmental evidence suggests the richness and diversity of the Japanese archipelago, with heavy densities of the Jomon population in 3500 BC located in central and eastern Japan (Kaner & Ishikawa 2007: 2).

Stable village sites with pits dwellings, storage areas and burial facilities have been excavated and studied, yet there is only a hint of cultivating nuts and plants.  Ongoing date conflicts with AMS results from human and animal bone have suggested the impact of the Yayoi culture to be pushed back to 1000 BC or 900 BC.  However the results could be contaminated with the ‘marine radiocarbon reservoir effect’, a natural distortion of dates and thus a possible need to recalibrate existing dates (Kaner & Ishikawa 2007: 4).  The outcome of the timing of adoption of agriculture in the Late Jomon/Yayoi period is still hotly debated. Yet the archaeological and osteoarchaeological evidence presents a hunter gather society managing to thrive without agriculture in diverse environments until later cultures and migrations of people came into contact with the Jomon culture (Mays 1998).

Further Information


Jurmain, R. Kilgore, L. & Trevathan, W.  2011. Essentials of Physical Anthropology International Edition. London: Wadworth.

Kaner, S. and Ishikawa, T. 2007. ‘Reassessing the concept of ‘Neolithic’ in the Jomon of Western Japan’. Documenta Preahistorica. 2007. 1-7.

Larsen, C. 1997. Bioarchaeology: Interpreting Behaviour From The Human Skeleton. Cambridge: Cambridge University Press.

Mays, S. 1999. The Archaeology of Human Bones. Glasgow: Bell & Bain Ltd.

Mithen, S. 2003. After The Ice: A Global Human History, 20,000-5000 BC.London: Weidenfeld & Nicolson.

Roberts, C. & Manchester, K. 2010. The Archaeology of Disease Third Edition. Stroud: The History Press.

Waldron, T. 2009. Palaeopathology: Cambridge Manuals in Archaeology. Cambridge: Cambridge University Press.

White, T. & Folkens, P. 2005. The Human Bone Manual. London: Elsevier Academic Press.