Literature Review
Medpor® Biomaterial and Porex Surgical Products
Cranial
Cenzi, R., Farina, A., Zuccarino, L., Carinci, F., “Clinical Outcome of 285 MEDPOR Grafts used for Craniofacial Reconstruction” The Journal of Craniofacial Surgery, Vol. 16, No. 4, pp526-536 (July 2005)
Porous polyethylene (MEDPOR) is an alloplastic material worldwide used for
craniofacial reconstruction. To evaluate complications and risk factors
associated with this synthetic graft, a retrospective study was performed.
A series of 285 MEDPOR grafts were placed in 187 patients. Age, sex,
diagnosis at admission, site, type of surgical insertion, type of fixation,
and outcome (no complications, anesthesia, exposure, infection, and implant
remodeling and removal) are considered. By means of univariate and multivariate
analyses, we detect variables most associated with poor outcome. Univariate
analysis showed that graft “survival” curves stratified according to (1)
diagnosis at admission and (2) site are statistically significant. Subsequently,
a Cox analysis was preformed: both variables are also predictors of graft outcome.
Porous polyethylene is a reliable alloplastic material that can be satisfactory
used for craniofacial reconstruction. However, some sites (i.e., nose, maxilla,
and ear) and diagnosis at admission (i.e., syndromic patients previously operated)
are related to an higher risk of implant failure.
This abstract is provided for educational purposes only. It
contains information about cleared uses of the product. It may contain other
potential uses not cleared by the Food and Drug Administration and not advocated
by the manufacturer. The uses and opinions expressed within the article are
those of the author derived from his or her personal experience with the product.
For additional information on cleared product specific indications and to request
a copy of the cleared labeling please contact the manufacturer's customer care
department.
Ki-Sun Hong, M.D.,Shin-Hyuk Kang, M.D., Jang-Bo Lee, M.D., Yong-Gu Chung, M.D., Hoon-Kap Lee, M.D., Heung-Seob Chung, M.D. Department of Neurosurgery, College of Medicine, Korea University, Seoul, Korea “Cranioplasty with the Porous Polyethylene Implant (MEDPOR®) for Large Cranial Defect” J Korean Neurosurg Soc 38, pp 96-101 (2005)
Objective: This paper describes our experience and implant technique for cranioplasty of a large cranial defects using a porous polyethylene implant (MEDPOR) and compares the results with polymethylmethacrylate (PMMA).
Methods: Sixteen cranioplasties were performed using MEDPOR (n=10) and PMMA (n=6) implants between June 2003 and January 2005. The criterion for patient enrollment was a defect larger than 10cm in diameter. This study compared the operation times and complications.
Results: The operation times ranged from 105 to 250 minutes (Mean 180°+44 minutes) in MEDPOR and from 185 to 460 minutes (Mean 128 minutes) in PMMA. The absolute operation times were shorter using the MEDPOR Implant and the differences were statistically significant (P=0.030). Satisfactory cosmetic results were obtained in all cases using the MEDPOR Implant and with no implant-related complications. Bone ingrowth to the MEDPOR Implant was presumed to be the result on an increase in Houndsfield units of the implant, particularly at the marginal areas in the serial follow-up brain computed tomography images.
Conclusion: It is believed that the properties of a MEDPOR Implant make this implant a good alternative to the existing methods of a cranial contour correction. However, a further follow-up study will be needed.
Key Words: MEDPOR,
Cranioplasty, Porous polyethylene implant, Large cranial defect
This abstract is provided for educational purposes only. It
contains information about cleared uses of the product. It may contain other
potential uses not cleared by the Food and Drug Administration and not advocated
by the manufacturer. The uses and opinions expressed within the article are
those of the author derived from his or her personal experience with the product.
For additional information on cleared product specific indications and to request
a copy of the cleared labeling please contact the manufacturer's customer care
department.
Liu, J.K., Gottfried, O.N., Cole, C.D., Dougherty, W.R., Couldwell, W.T., “MEDPOR® Porous Polyethylene Implant for Cranioplasty and Skull Base Reconstruction” Neurosurgery [Online Serial], Directory
http://www.neurosurgery.org/abstractcenter April 2004
Object: Cranial reconstruction after skull-base surgery is important for restoration of function and cosmesis. The authors describe their experience with the MEDPORŇ Porous Polyethylene Implant for cosmetic cranioplasty and reconstruction after skull base surgery.
Methods: MEDPOR, a biocompatible implant, is flexible and can be contoured to facilitate surgical reconstruction of small to medium (< 8cm) convexity or cranial base defects resulting from a variety of skull-base approaches. This method provides similar cosmetic results to standard alloplast cranioplasty while decreasing operating time. The porous nature of the material allows ingrowth of soft tissue and bone to increase implant strength and decrease the risk of infection. This material can also be used safely in reconstruction of the cranium and skull base adjacent to the paranasal sinuses.
Conclusions: The
authors have used the MEDPOR Porous Polyethylene Implant in 611
standard cranial and skull-base procedures and have achieved
excellent cosmetic results and no implant-related complications.
This abstract is provided for educational purposes only. It
contains information about cleared uses of the product. It may contain other
potential uses not cleared by the Food and Drug Administration and not advocated
by the manufacturer. The uses and opinions expressed within the article are
those of the author derived from his or her personal experience with the product.
For additional information on cleared product specific indications and to request
a copy of the cleared labeling please contact the manufacturer's customer care
department.
Day, J.D., Chen, D.A., Arriage, M., “Translabyrinthine Approach for Acoustic Neuroma,” Neurosurgery, Volume 54, Number 2 (February 2004)
The translabyrinthine approach has been popularized during the past 30 years for the surgical treatment of acoustic neuromas. It serves as an alternative to the retrosigmoid approach in patients when hearing preservation is not a primary consideration. Patients with a tumor of any size may be treated by the translabyrinthine approach. The corridor of access to the cerebellopontine angle is shifted anteriorly in contrast to the retrosigmoid approach, resulting in minimized retraction of the cerebellum. Successful use of the approach relies on a number of technical nuances that are outlined in this article.
KEY WORDS:
Acoustic neuroma, Surgery, Translabyrinthine approach, Vestibular
schwannoma
This abstract is provided for educational purposes only. It
contains information about cleared uses of the product. It may contain other
potential uses not cleared by the Food and Drug Administration and not advocated
by the manufacturer. The uses and opinions expressed within the article are
those of the author derived from his or her personal experience with the product.
For additional information on cleared product specific indications and to request
a copy of the cleared labeling please contact the manufacturer's customer care
department.
Mesiwala, A.H., Lipson, A.C., Gelfenbeyn, M., Futran, N., Silergeld, D.L.,
Rostomily, R.C., “Assessment of a Custom-made Linear High-density Porous
Polyethylene Implant for Craniofacial Reconstruction” Presented at Congress
of Neurological Surgeons Denver, Colorado 53rd Annual Meeting
October 18 – 23, 2003
Introduction: For routine cranioplasty, in situ reconstruction with polymer,
mesh, bone cement or split thickness calvarial grafts achieve satisfactory
results. However, for large defects in cosmetically sensitive or
anatomically complex regions, these techniques can be time-consuming and
acceptable cosmetic results are more difficult to achieve, and in high-risk
patients, have a significantly increased incidence of infection. To address
these issues, we report our preliminary experience with custom-made linear
high-density porous polyethylene implants (MEDPOR® Porex Corp., Atlanta,
Georgia, USA) that promote vascular in-growth.
METHODS: Implants are generated from a CT-based stereolithographic model of
the skull and defect which is refined by clay sculpting to optimize anatomic
contours, eliminate bone edge gaps and provide sites for rigid fixation. A
retrospective chart review was performed to evaluate our preliminary experience.
RESULTS: Thirteen (13) patients with large defects in cosmetically sensitive
regions were implanted with good to excellent anatomic contour. Little, if
any, intraoperative modification was needed prior to rigid fixation with
standard cranial fixation systems, such that operative time and blood loss
(average, 195cc) were minimized. Two implants were removed, one for an
implant-related infection (1/13, 7.6%) and another in a multiply operated
and radiated patient to prevent implant contamination due to scalp breakdown
(1/13, 7.6%). Both patients were re-implanted without complication.
Pre-implant tissue expansion in two cases with extensive skin retraction
allowed excellent tension-free tissue coverage. Robust implant vascularization
and local tissue in-growth was noted in one re-operated case.
CONCLUSIONS: Custom-made Porex implants provide excellent anatomic contour
for reconstruction of large defects in cosmetically sensitive or anatomically
complex regions and can be rigidly fixed in a timely fashion with standard
techniques. Their porous structure promotes vascular and soft tissue ingrowth
potentially minimizing infection risks (1/13 in this series of high-risk
patients). Overall, they represent a valuable addition to the existing
armamentarium of options for cranial reconstruction.
This abstract is provided for educational purposes only. It
contains information about cleared uses of the product. It may contain other
potential uses not cleared by the Food and Drug Administration and not advocated
by the manufacturer. The uses and opinions expressed within the article are
those of the author derived from his or her personal experience with the product.
For additional information on cleared product specific indications and to request
a copy of the cleared labeling please contact the manufacturer's customer care
department.
Berk, C., Savas, A., Kanpolat, Y., "The Use of High Density Polyethylene Implants For Craniectomy Repair in Posterior Fossa Surgery", Journal of Neurological Sciences (Turkish), Vol. 17, 2000
During the period between October 1996 and April 1998; at the
Department of Neurosurgery, Ankara University School of Medicine;
sixteen patients undergoing posterior fossa surgery had their
craniectomy defects repaired with high-density polyethylene
implants. The patients were followed-up for an average of 11.2
months. During the follow-up period, the high-density polyethylene
implants proved to be highly biocompatible and with good cosmetic
results. The computerized tomographic scans at the sixth postoperative
month revealed the implant to be almost integrated to the adjacent
bony structures. None of the patients had any implant related
problems in the postoperative period. As a result high-density
polyethylene implants are found to be advisable for use in
patients for the repair of craniectomy defects in posterior
fossa surgery
This abstract is provided for educational purposes only. It
contains information about cleared uses of the product. It may contain other
potential uses not cleared by the Food and Drug Administration and not advocated
by the manufacturer. The uses and opinions expressed within the article are
those of the author derived from his or her personal experience with the product.
For additional information on cleared product specific indications and to request
a copy of the cleared labeling please contact the manufacturer's customer care
department.
Wheeler, D.L., Eschbach, E. J., Hoellrich, R. G., Montfort M. J., and Chamberland D. L. “Assessment of Resorbable Bioactive Material for Grafting of Critical-size Cancellous Defects,” Journal of Orthopedic Research, Vol. 18, No. 1, 2000, pp. 140 – 148 (2000)
Bioactive glasses form a surface apatite layer in vivo that enhances the formation and attachment
of bone. Sol-gel Bioglass graft material provides greater nanoscale
porosity than bioactive glass (on the order of
50 – 200 A), greater particle surface area, and improved resorbability, while maintaining
bioactivity. This study histologically and biomechanically evaluated,
in a rabbit model, bone formed within critical-sized
distal femoral Cancellous bone defects filled with 45S5
Bioglass particulates, 77S sol-gel, or 58S sol-gel Bioglass and
compared the bone in these defects with normal, intact, untreated Cancellous bone
and with unfilled defects at 4, 8, and 12
weeks. All grafted defects had more bone within the area than did unfilled
controls (p < 0.05). The percentage of bone within the defect
was significantly greater for the 45S5 material than for the
585 or 77S material at 4 and 8 weeks (p < 0.05), yet
by 12 weeks equivalent amounts of bone were observed for all
materials. By 12 weeks, all grafted defects were equivalent to
the normal untreated bone. The resorption of 77S and
58S particles was significantly greater than that of 45S5 particles
(p < 0.05). Mechanically, the grafted defects had
compressive stiffness equivalent to that of normal bone at
4 and 8 weeks. At 12 weeks, 45S5-grafted defects had significantly greater
stiffness (p < 0.05). At 8 and 12 weeks, all
grafted defects had significantly greater stiffness than unfilled
control defects (p < 0.05). In general, the 45S5-filled
defects exhibited greater early bone ingrowth than did those filled
with 58S or 77S. However, by 12 weeks, the bone ingrowth in each
defect was equivalent to each other and to normal bone. The 58S
and 77S materials resorbed faster than the 45S5 materials.
Mechanically, the compressive characteristics of all grafted
defects were equivalent or greater than those of normal bone
at all time points.
This abstract is provided for educational purposes only. It
contains information about cleared uses of the product. It may contain other
potential uses not cleared by the Food and Drug Administration and not advocated
by the manufacturer. The uses and opinions expressed within the article are
those of the author derived from his or her personal experience with the product.
For additional information on cleared product specific indications and to request
a copy of the cleared labeling please contact the manufacturer's customer care
department.
Park, Hun, Dujovny, Manuel, Diaz, Fernando,
Guthikonda, Murali, “Biomechanical Properties Of High-density Polyethylene
For Pterional Prosthesis” Neurological Research, Volume 24, pp 671-676
(October 2002)
The pterional approach is the most popular surgical technique in
aneurysm and skull base tumor removal. Reconstruction of the temporal
contour deformity due to craniotomy requires graft implantation.
Porous high-density polyethylene (PHDPE) as a craniofacial and
pterional implant material recently became available. However,
material properties of the pterional implant are not yet known.
In order to measure the biomechanical properties of PHDPE, we
implemented the tensile test, the three-point bending test and
the water displacement method for density measurement. Elastic
modulus varies from 227 to 307 Mpa. Density range is 0.68 and
0.7 depending on the size of pores. The data can be used to
study the character of the porous high-density polyethylene
implant, how it resists stress or fatigue in combination with
conventional plating systems.
DISCUSSION:
Various alloplastic implant material have been used for facial
reconstruction and temporal contour deformity. As an ideal material
for restoration, it should be considered whether the material has
ideal characteristics. Those characteristics should be: easy to
obtain; noncarcinogenic; no fumes and no toxicity; sterilizable;
compatible with diagnostic imaging radiolucent, MRI inert and
nonscattering; high impact strength; easy to design and manipulate
the shapes; securable material to attach to the skull; usable with
stereolithography; not heavy; nonthermal and electrical conductance;
nonmagnetic; and noncorrosive and nonionizable. Based on the
literature from medical and engineering fields, the PHDPE implant
materials currently seem to evolve to satisfy those characteristics.
The MEDPOR Implant, as a form of highly compatible and long term
tissue stable material, is available for pterional application.
(Neurol Res 2002; 24: 671-676)
SPG-1056-111502-01
This abstract is provided for educational purposes only. It
contains information about cleared uses of the product. It may contain other
potential uses not cleared by the Food and Drug Administration and not advocated
by the manufacturer. The uses and opinions expressed within the article are
those of the author derived from his or her personal experience with the product.
For additional information on cleared product specific indications and to request
a copy of the cleared labeling please contact the manufacturer's customer care
department.
Janecka, I.P. "New Reconstructive Technologies
In Skull Base Surgery, Role Of Titanium Mesh and Porous Polyethylene",
Arch Otolaryngol Head Neck Surg, Vol. 126, pp 396-401 (Mar 2000)
Objective: To report on 8 years of experience with 156 titanium
mesh and porous polyethylene implants used for craniofacial reconstruction
after skull base surgery in 100 patients.
Design: Cohort study with a mean follow-up of 5 years.
Setting: Population based.
Patients: A consecutive sample of 100 patients treated for skull
base tumors or craniofacial trauma who underwent reconstruction
with 156 3-dimensional titanium mesh and/or porous polyethylene
implants. A retrospective review of the Skull Base Program database,
along with photographic and imaging documentation, was undertaken.
Main Outcome Measures: Rate of complications as well as the degree
of functional and esthetic reconstruction. Intervention: The reconstructive
technique focused primarily on the substitution of removed craniofacial
skeleton for oncologic reasons or soft tissue defects.
Results: After completion of follow-up (mean, 5 years), all 100
patients remained healed except for 7 patients (7%) with 8 implants
(5%). Overall, excellent craniofacial symmetry and stability were
achieved with both types of implants.
Conclusions: Immediate craniofacial skeletal reconstruction and
soft tissue augmentation is feasible with 3-dimensional titanium
mesh and porous polyethylene implants. The reviewed 8-year evolution
in the use of these technologies (156 implants in 100 patients)
highlights the excellent tolerance of these implants (5% implant
complication rate) in 100 patients (7% complication rate). The few
encountered complications were judged to be primarily related to
the quality of the overlying soft tissue and not to the implants
themselves. The advantages of using these implants for immediate
3-dimensional skeletal and soft tissue substitution, including availability,
easy contouring, stability, primary healing, and tolerance of adjuvant
therapy, translate to an improved function and esthetic appearance,
with a better quality of life for patients.
This abstract is provided for educational purposes only. It
contains information about cleared uses of the product. It may contain other
potential uses not cleared by the Food and Drug Administration and not advocated
by the manufacturer. The uses and opinions expressed within the article are
those of the author derived from his or her personal experience with the product.
For additional information on cleared product specific indications and to request
a copy of the cleared labeling please contact the manufacturer's customer care
department.
Kikkawa, D.O., Weisman, R.A., Orloff, L.A. "Orbital Rim Reconstruction
Following Maxillectomy", presented at the American Society Surgeons
Meeting, New Orleans, Louisiana, U.S.A. (Fall 1998)
Orbital reconstruction following maxillectomy for paranasal sinus
neoplasm presents a difficult challenge for the orbital surgeon.
Glode dystopia, extraocular motility restriction, ectopion, nasolacrimal
duct obstruction and cosmetic deformity may be present in patients
who have undergone globe sparing resection of sinus malignancy.
Secondary orbital rim and malar reconstruction with porous polyethylene
was used in five patients who underwent maxillectomy for paranasal
sinus malignancy. A prefabricated porous polyethylene rim and malar
implant was placed via a transconjunctival approach in all patients
and fixated with titanium microplates. All patients had primary
reconstructionof the orbital walls at the time of initial resection
and were tumor free for a minimum of one year prior to orbital rim
reconstruction. One patient developed a recrrence of squamous cell
carcinoma in the orbital apex. Implant, globe and lid position were
stable in all patients with a minimun follow-up of six months.
This abstract is provided for educational purposes only. It
contains information about cleared uses of the product. It may contain other
potential uses not cleared by the Food and Drug Administration and not advocated
by the manufacturer. The uses and opinions expressed within the article are
those of the author derived from his or her personal experience with the product.
For additional information on cleared product specific indications and to request
a copy of the cleared labeling please contact the manufacturer's customer care
department.
Janecka, I.P., Tiedemann, K., "Skull
Base Surgery: Anatomy, Biology and Technology", Lippincott-Raven
(1997) and Sauer, B.W. "Implants - Technical Aspects of Porex Surgical
Polyethylene Implants", Chapter 13, pp 353-375
Authors describe history of animal investigation on use of porous
polyethylene as implantable biomaterial. Examples of clinical use
of MEDPOR® Biomaterial in craniofacial surgery are given and
reviews of clinical papers by other authors are presented.
This abstract is provided for educational purposes only. It
contains information about cleared uses of the product. It may contain other
potential uses not cleared by the Food and Drug Administration and not advocated
by the manufacturer. The uses and opinions expressed within the article are
those of the author derived from his or her personal experience with the product.
For additional information on cleared product specific indications and to request
a copy of the cleared labeling please contact the manufacturer's customer care
department.
Couldwell, W. T., Chen, T. C., Weiss,
M. H., Fukushima, T. and Dougherty, W. "Cranioplasty With The MEDPOR®
Porous Polyethylene FLEXBLOCK™ Implant", The Journal of
Neurosurgery, Vol. 81, pp 483-486 (1994)
The experience of using the MEDPOR® FLEXBLOCK™ implant
in 25 patients with small to medium-sized cranial defects is described.
Excellent cosmetic results were achieved in all patients, with no
implant-related complications. The authors conclude that the FLEXBLOCK
design combines strength with flexibility and the material's porosity
permits tissue ingrowth, increasing implant strength and decreasing
the risk of infection. They also assert that MEDPOR's ease of implantation
decreases operative time when compared to methylmethacrylate.
This abstract is provided for educational purposes only. It
contains information about cleared uses of the product. It may contain other
potential uses not cleared by the Food and Drug Administration and not advocated
by the manufacturer. The uses and opinions expressed within the article are
those of the author derived from his or her personal experience with the product.
For additional information on cleared product specific indications and to request
a copy of the cleared labeling please contact the manufacturer's customer care
department.
Lacey, M. and Antonyshyn, O. "Use Of Porous
High-Density Polyethylene Implants In Temporal Contour Reconstruction",
Journal of Craniofacial Surgery, Vol. 4, pp 74-78 (1993)
Reconstruction of the temporal contour deformities is described
using porous high density polyethylene material in 16 patients treated
between July 1988 and September 1990. MEDPOR®implants were carved
to the required shape for contour augmentations. The techniques
were reported to be simple and effective in correcting soft tissue
volume defects.
Applications for the MEDPOR FLEXBLOCK™ implant are described
in the craniofacial skeleton. The FLEXBLOCK implant was found to
be suited for repair of small to medium-sized cranial defects and
correction of contour deformities. The implant was used in 12 patients
over a two-year period without any complications. The use of the
implant for supra-orbital rim defects is illustrated in two patients
This abstract is provided for educational purposes only. It
contains information about cleared uses of the product. It may contain other
potential uses not cleared by the Food and Drug Administration and not advocated
by the manufacturer. The uses and opinions expressed within the article are
those of the author derived from his or her personal experience with the product.
For additional information on cleared product specific indications and to request
a copy of the cleared labeling please contact the manufacturer's customer care
department.
Wellisz, T., Dougherty, W., Gross, J. “Craniofacial Applications For The MEDPOR® Porous Polyethylene FLEXBLOCK™ Implant,” The Journal of Craniofacial Surgery, Volume 3, Number 2, pp 101-107 (September 1992)
We describe use of FLEXBLOCK, a newly designed MEDPOR Porous Polyethylene Implant. This implant is ideally suited for repair of small to medium-sized cranial defects and correction of contour deformities. MEDPOR is used for a wide variety of maxillofacial procedures, and its properties make it an excellent choice for the cranium. It is a highly stable and somewhat flexible porous alloplast that has been shown to exhibit rapid soft-tissue and bone ingrowth. FLEXBLOCK, which was designed as an onlay for calvarial bone graft donor sites, has a smooth exterior surface and a series of conical ridges on its undersurface that enable easy bending, good contour adaptability, and suitable strength. We used the MEDPOR FLEXBLOCK Implant in 12 patients over 2 years for correction of contour deformities, cranial defects, and reconstruction of the supraorbital rim. There were no complications. Larger cranial defects and complex reconstructions can be performed using customized MEDPOR Implants. The properties of MEDPOR and the FLEXBLOCK design make this implant an excellent alternative to the existing methods of cranioplasty and cranial contour correction.
This abstract is provided for educational purposes only. It
contains information about cleared uses of the product. It may contain other
potential uses not cleared by the Food and Drug Administration and not advocated
by the manufacturer. The uses and opinions expressed within the article are
those of the author derived from his or her personal experience with the product.
For additional information on cleared product specific indications and to request
a copy of the cleared labeling please contact the manufacturer's customer care
department.
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