Biomedical Engineering Reference
In-Depth Information
Hanasono et al. [49] presented the results of six
delayed calvarial reconstructions using PEEK
Optima-LT patient-specific implants. All patients had
been treated for an infection of their bone flap. Three
patients had a previous reconstruction and infection
with an alternate material. Four patients had a defect
too large to be treated with autologous bone. Overall,
the authors observed no infections, an especially
positive outcome as one patient had already received
multiple subsequent surgeries. All implants fit well,
with one having to be trimmed with a cutting burr to
avoid compressing soft tissue of a prior pericranial
flap overlying the edge of the defect. The study
concluded that implants were well tolerated in
patients with a history of prior surgery, infection,
radiation, and cerebrospinal fluid leakage.
Chacon-Moya et al. [47] reported the case of an
esthesioneuroblastoma that was treated with anterior
craniofacial resection and radiation. The patient
subsequently presented with osteomyelitis and
osteoradionecrosis with the loss of the frontal cranial
vault, which was treated conservatively with cleaning,
debridement, sequestrectomy, and antibiotics. After
recurrent infection, the patient was treated with
a local resection that left a large defect, approximately
10.5
Figure 15.14 EOS HPS PEEK cranial implant. The
image is reprinted here with the permission of the
manufacturer.
product lines include implants manufactured by
machining PEEK Optima-LT from Invibio (Lanca-
shire, UK). On the emerging technology front, EOS
(Munich, Germany) is testing a PEEK implant
produced by selective laser sintering. Producing the
implant by this additive laser sintering is purported to
be faster and more economical, providing a fully
customized implant in less than 2 days. Their new
design, shown in Fig. 15.14 , is formed as a mesh
scaffold that is intended to promote bone ingrowth
and facilitate infiltration with an HA-filled bio-
absorbable polymer. The implant is currently under-
going animal trials.
6.4 cm. After the infection was cleared, the
defect was reconstructed with a customized PEEK
implant. Immediate intra- and postoperative evolutions
were satisfactory and there were no complications.
Other studies have found similarly optimistic
results. Kim et al. [45] presented a series of four cases
of trauma and oncological defects that were recon-
structed using customized PEEK implants. After
16 e 20 months, no patients had any implant-related
complications, including infection, extrusion, or
malposition. All patients improved in aesthetics and
function. In another study, Lethaus et al. [50] operated
on 12 patients using customized titanium and PEEK
implants. Outcomes were not presented, but the
implants were reported to fit accurately, without any
on-site adjustments to the skull or implant. Although
short-term results are promising, long-term evidence
is still required to grasp the full potential and draw-
backs in using PEEK as a cranioplastic implant.
15.5 Summary
Semirigid fixation for trauma and arthroscopy has
been finding favor as the fracture healing and stress
shielding literature continues to develop. Although
PEEK fracture fixation has a number of proposed
benefits for fracture healing, it remains to be seen
whether a PEEK solution can provide better clinical
and functional outcomes relative to metallic fixation.
PEEK has, however, found early clinical success in
arthroscopic and cranial defect markets. It is expec-
ted that performance of PEEK implants for each of
these applications will continue to improve as
product design methodologies innovate to optimize
and capitalize on the unique material property
advantages inherent in this material.
15.4.4 Current Landscape for
PEEK Cranial Defect Implants
Currently, PEEK cranioplastic implants are avail-
able from Synthes (West Chester, PA) and Maastricht
Instruments (Maastricht, Netherlands). The available
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