Low-cost acrylic cranioplasty using an implant cast on a pre-printed 3D polylactic acid model in a child with a complicated osteolytic extradural hydatid cyst

doi:10.21203/rs.3.rs-5026563/v1

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Case Report

Low-cost acrylic cranioplasty using an implant cast on a pre-printed 3D polylactic acid model in a child with a complicated osteolytic extradural hydatid cyst

https://doi.org/10.21203/rs.3.rs-5026563/v1

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Cranioplasty to restore calvarial defects involves reconstruction with alloplastic materials or autologous tissues in order to provide the best protection to all intracranial contents. Sometimes, autologous bone may not be available; therefore, different materials have emerged such as polymethylmethacrylate plate, titanium mesh, and hydroxyapatite. However, when it is impossible to replace the autologous bone, the aesthetic result is generally unsatisfactory. Some techniques like neuronavigation and computer-aided design can help overcome these problems. However, these techniques cost too much. By combining these techniques and that of 3D printing, some authors have provided an aesthetically precise and cost-effective implant using polymethylmethacrylate in patients with large craniectomy defects.

Here, the authors report a case of a 6-year-old child with history of two previous surgeries for osteolytic extradural and complicated hydatid cyst followed by intra cerebral dissemination who was admitted for recurrence of his hydatid pathology. The child was scheduled for hydatid cysts resection and cranioplasty using the polymethylmethacrylate, after removal of the hydatid cysts, using a bone flap cast on a pre-printed cost effective polylactic acid 3D mold.

hydatid cyst

cranioplasty

polymethylmethacrylate

surgery

Cranioplasty to restore postoperative or post-traumatic calvarial defects involves reconstruction with alloplastic materials or autologous tissues in order to provide the best protection to all intracranial contents including brain parenchyma, vascular tissues, and cerebrospinal fluid (CSF). Cranioplasty can reestablish boundaries between intra- and extracranial structures, and restore the craniofacial contour, providing support for any overlying soft tissues [1]. The first signs of cranial and facial reconstruction were found in Egypt between 3,000 and 2,500 BC. In the 16th century, Fallopius covered the cranial defect of trepanation with gold plates. Much later, during the 19th century, cranial reconstruction with bone grafts was introduced and became popular during the 20th century with the help of technology and the advent of alloplastic materials [1, 2]. Cryopreserved autologous bone have been the most widely used material, since it best meets the basic characteristics to be considered the ideal material [3]. Sometimes, autologous bone may not be available due to fracture, contamination, or even lack of availability of a tissue bank; therefore, different materials have emerged such as polymethylmethacrylate plate, titanium mesh, and hydroxyapatite, among others [4]. However, when it is impossible to replace the autologous bone or when the bone defects are quite significant, the aesthetic result is generally unsatisfactory because it will be difficult to obtain an adjustment and a desired thickness as well as a smooth surface [5]. Some techniques like neuronavigation and computer-aided design can help overcome these problems [6]. However, these techniques cost too much. By combining these techniques and that of 3D printing, some authors have provided an aesthetically precise and cost-effective implant using polymethylmethacrylate in patients with large craniectomy defects [7].

Through this report, the author will describe in details this low-cost technique using a three-dimensional skull modeling with images from a multi-bar scanner. The reconstruction of a skull mold from a mirror image of the healthy side is obtained after more advanced computer processing of the 3D model. The mold was made by a 3D printer using a cost effective polymer called polylactic acid (PLA).

We present the case of a 6-year-old child, former patient of our neurosurgery department, who underwent excision surgery twice for a primary left cerebral parieto-occipital hydatid cyst. At the first surgery, the cyst was extra parenchymal, complicated and communicating with the subcutaneous tissues through bone defects. It was totally removed. Infected and perforated bone flap was not put back in place (Fig. 1; [8]). The postoperative course was uneventful and the patient was discharged under complementary medical treatment made of albendazole and scheduled for subsequent cranioplasty. Three months later, our patient underwent the second surgery for homolateral intra-axial dissemination of his hydatid cyst through an embolization of embryos or scolices through blood. Resection of both new intra-axial cysts was not done according to Dowling-Orlando’s given the opposite cerebral cortex was quite thin. The membrane of both cysts was completely removed and both cysts cavities were irrigated abundantly with warm hypertonic saline. The postoperative course was also uneventful and our patient was discharged under his old medical treatment made of albendazole. Four months later, the child was brought back by his mother again for rapidly onset of constrictive occipital long-lasting headaches predominantly in the morning and few episodes of slight abilious nausea without fever or other localizing neurological signs.

Upon examination, the child was awake and well oriented in time and space. Examination revealed preserved higher functions, unaltered cranial nerves–as far as possible based on the patient's age and cooperation. His pupils were normoreactive to light and he had no neurological deficits or cranial nerve damage. Bilateral fundus examination revealed no papillary edema and the rest of his general physical examination was without abnormalities. There was no meningeal or cerebellar involvement. Both postsurgical scar and skin next to the surgical site and bone defect were of good vitality (Fig. 2). His brain magnetic resonance imaging (Fig. 3) showed a left parieto-occipital postoperative porencephalic cavity surrounded by gliosis and stigmata of old bleeding. It is associated with multiple adjacent left parietal intra-axial cysts, with clean walls and homogeneous fluid content in hyposignal on T1-weighted sequence and hypesignal on T2-weighted sequence measuring 21 x 15mm, 37 x 21mm, 17 x 11mm, 12mm and 11mm. These lesions are devoid of signal abnormality or enhancement after Gadolinium chelate injection. A new multisliced computerized tomography (MSCT) with 3D reconstruction (Fig. 4) was then performed to assess bone defect and schedule cranioplasty. The personalized images were extracted from preoperative MSCT scans in Digital Imaging and Communications in Medicine (DICOM) format and converted to STereoLithography (STL) file format using the open source software Invesalius 3.1–3D medical imaging reconstruction software (licensed under GNU GPL). From a 3D CT reconstruction, we created the implant model with the MeshMixer for surface 3D modeling software. Specifically, by taking advantage of the "mirror" command applied to the healthy skull right side, we obtained the external surface of the left flap ensuring cranial symmetry. As a negative of the obtained implant model, we defined a lower surface and an upper surface of the implant to subsequently create the two-part composite mold. Finally, we inserted three alignment posts to facilitate self-centering of the two parts of the mold. This mold was printed using a “Raise3D Pro3 Plus 3D” printer as a professional dual extruder 3D printer for easier 3D printing experience and a large build volume. The print used PLA (polylactic acid) filament. This workflow was carried out within the company Three-axis Innovation (Fig. 5).

The patient was therefore re-operated, after informed consent of his legal guardian, using the same skin incision and the same surgical approach in prone position with his head maintained in a classic horseshoe head rest. He underwent a complete cysts excision after a gentle puncture with a trocar needle to prevent their dissemination into the subarachnoid spaces. The surgical site and all cystic cavities were irrigated abundantly with warm 3% hypertonic saline for more than 15 minutes (Fig. 6). The dura mater was sutured tightly in a classic fashion and the bony edges of the craniectomy were well exposed. The second surgical time was dedicated to cranioplasty. For this, we washed both parts of the mold thoroughly with sterile and endotoxin-free physiological saline (NaCl 0.9%) after sterilizing it in a high-level disinfectant called CIDEX™ OPA solution. This solution is used for reprocessing reusable heat-sensitive semi-critical medical devices such as anesthesia equipment and endoscopic. Then we proceed to prepare the surgical cement in a sterile bowl where the premixed PMMA polymer and the monomer are both mixed in an appropriate ratio. This process continues until the mixture polymerizes and finally forms a thick paste without lumps. Before interposing the paste between the two surfaces of the mold, these are covered with sterile paraffin oil to prevent the PMMA from sticking. The PMMA paste is then placed on the convex surface of the mold and spread evenly and carefully in layers to obtain a smooth surface. The concave surface is then placed on the convex one adapting to the contour and the whole assembly is held firmly in place by pressing with hands for few seconds until the PMMA sets and becomes firmer. The overflow of the paste from all different sides of the mold is removed flush with the edges immediately before it hardens. The model mold is removed and left intact for few minutes. The exothermic reaction is reproduced on table and the new implant is rinsed abundantly with sterile and endotoxin-free physiological saline (NaCl 0.9%) to cool it and to enhance its rigidity. After checking the hemostasis which was maintained satisfactorily throughout the surgery, our prepared PMMA implant is placed on the cranial defect and fixed to the vault using transosseous sutures (Fig. 7). The wound is closed with a subcutaneous suction Redon wound drainage and the skin stiches were performed in a classic way. The postoperative course was uneventful. His postoperative scan showed a total disappearance of both hydatids cysts with good location of the bone implant filling his old cranial defect (Fig. 8). The child's cranial curvature was recovered and appears satisfactory compared to the contralateral side (Fig. 9). His surgical wound was dry without any dripping of the cerebrospinal fluid. The boy was discharged from our department 5 days postoperatively in a good clinical condition. His treatment made of albendazole was resumed at a dose of 15 ml per days divided in two doses and was scheduled for an appointment at our outpatient clinic. He did not experience any side effects, and his recovery went exceptionally smoothly. He completed six weeks of post-surgical albendazole with resolution ad integrum and without sequelae.

Cranial vault reconstruction remains a big challenge today as it requires the involvement of a multidisciplinary team. The main factors to take into account are the patient’s age, area and size of the defect, as surgery and reconstruction type will depend on them [9]. There are multiple surgical techniques for cranial reconstruction previously described in the literature. Among which the most notable are prefabricated flaps, the use of tissue expanders [10], the placement of titanium mesh and the bipedicled galeal flap [11], or even the use of autologous bone preserved in ethylene oxide [12] among many others, presenting good postoperative results. However, most of these surgical techniques imply a higher cost for patients, require more than one surgical event, and are technically much more complex.

In pediatric population, particularly, the replacement of bone flaps seems advantageous and easier because their bone material can be reincorporated during the process of maturation and growth. However, in this type of patients, bone resorption can reach up to 50% of cases [13], which requires additional reconstructive surgery. Alloplastic materials usually used in children include the methyl methacrylate, hydroxyapatite cement, demineralized bone and even titanium mesh. In our case, we were unable to replace the patient’s autologous bone flap during the first surgery because it was infected and perforated [8], nor during the second surgery [14] at time of intracerebral dissemination so that we were forced to use alloplastic materials. In fact, several alloplastic choices exist. These choices are based on patient conditions, cost and surgeon preferences. They include metals such as titanium (ti), acrylics such as polymethylmethacrylate (PMMA), plastics such as polyether ether ketone (PEEK) and other types of materials that include cement bones or bioceramics such as hydroxyapatite [15].

The use of alloplastic PMMA prostheses has become a safe and practical treatment option, which avoids the use of bone grafts, preserving the bone and with much lower morbidity. This material has already been used for several decades, since it was first described in an article in 1949 [16]. PMMA have multiple advantages among which the resistance, stability and biocompatibility that the material presents stand out, as well as being radiotransparent, which causes minimal artifacts in the magnetic resonance, and with a rigidity and resistance similar to bone but with low weight compared to it. It should also be noted that among the materials available for cranial reconstruction, it is the lowest cost [17]. However, it requires the use of technology, is more expensive and its fixation and integration can be complex since it entails a higher prevalence of infection, greater tissue reaction and rejection [17, 18]. In our patient we used the PMMA as material for cranioplasty for its benefits and its sole disponibility in our institution. PMMA may be used either as prefabricated, i.e. the implant is manufactured before surgery using computer-aided design and used directly during the procedure, or as a molded model where the implant is prepared intraoperatively using 3D printed molds designed using the computer-aided design [7] as it was done in our patient. This technique has several benefits. However, it is not devoid of disadvantages and limitations. In 2010, Goh et al. [19] conducted a study on 31 patients who had cranioplasty using this technique. They concluded that the latter was safe and precise. However, they were not able to control the implant thickness. In our case and with our technique, we were able to obtain a suitable thickness of the implant almost superimposed on the contralateral healthy side. In 2013, Stieglitz et al. [20] conducted a case series of 27 patients and concluded to the same inconvenience. However, they mentioned that the technique was fast, accurate and cost-effective as it was reported also by Marbacher et al. [21] through a series of 27 patients. Another disadvantage of the technique is that the implant size is smaller than the cranial bone defect, something which was not encountered in our case with our technique. This was reported by Kim et al. in 2012 [22]. However, they reported good cosmetic results for large and complex cranial defects. More recently, Gopal et al. [7] conducted a study on 114 patients who underwent cranioplasty, 25 of whom used 3D printed models due to unavailability of autologous bone as it was seen in our patient. They concluded that this technique is useful for large bone defects and without any risk to surrounding tissues. They did, however, report two cases of infection due to compromised scalp wound. In our case, we share the same benefits as them but we did not have any infection or other complication. This infection problem of the PMMA neo-bone flap is due to its irregular and non-smooth surface when it is designed and molded manually [23]. This notion was confirmed by Lee et al. [24] who reported, through a series of 131 patients, that the infection rate of prefabricated PMMA implants is lower than those molded manually. Therefore, designing a smooth surface to mold the implant using a template reduces the risk of infection of the implant as it was done in our patient. Another disadvantage of the technique is the asymmetry of the temporal region due to atrophy of the temporalis muscle [25]. To address this problem, Gopal et al. [7]suggests providing varying thickness of the implant in the temporal region.

In low-income countries where “out-of-pocket” payments for healthcare costs are common because a small percentage of the population is covered by health insurance, our technique is cost-effective, economical and easier to use in giving reproducible results. The cost is lower than even generic non-cast titanium plate and its production time is minimal. The average cost of cranioplasty was CAD$18,335 ± CA$10,265 for hand-cast titanium implants and CAD$31,956 ± CAD$31,206 for custom titanium implants. For PMMA, the cost is CAD$20,786 ± CAD$13,075, CAD$14,291 ± CAD$5,562 for autogenous implants, and CAD$27,379 ± CAD$4,945 for PEEK implants [26]. All taxes included, the cost of our technique does not exceed 2000,00 Tunisian dinars (CAD$ 888,920) including the price of PMMA which does not exceed 360,00 Tunisian dinars (CAD$160,010). This method using 3D printed molds remains simple, rapid, biomechanically stable and aesthetically precise. Emphasis should be placed on avoiding any direct contact of the PMMA implant with tissues caused by an exothermic reaction. The technique also helps create an implant with a smoother surface, which minimizes the risk of infection [20, 21, 22, 24].

Additive manufacturing and the practice of reconstruction based on 3D imaging will allow very precise processing of data and even faster manufacturing of more sophisticated and better-fitting heterologous implants [27]. In the future, patient-specific, recommended and personalized implants will be manufactured to create a 3D printed biodegradable scaffold. This will guide bone regeneration and stimulate bone growth in the host which allows the required cranial proportions and measurements to be achieved [28].

In view of the very satisfactory results of our patient, we recommend the generalization of the use of the technique, especially for developing and low-income countries. However, given the limitations of the literature studies, additional research and investigations are necessary to confirm the practical applicability of this technique on a broader scale.

3D printing technology is now a valuable new technique for improving the design of custom implants used even for cranioplasties with complex geometry. This technique, described in our report, uses computer-aided design and results in an ideal and cost-effective aesthetic effect. The main advantage of the technique is being reusable without adding additional production costs. However, it is necessary to consider a more detailed evaluation on a larger sample to evaluate its long-term aesthetic and functional results.

Author contribution

All the authors contribute to write this manuscript.

Availability of data and materials: Mehdi Borni was responsible for the work and the conduct of the study, had access to the data, and controlled the decision to publish.

Ethics approval and consent to participate: Written informed consent was obtained from the patient’s legal guardian for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Consent for publication: Written informed consent was obtained from the patient’s legal guardian for publication of this case report and accompanying images.

Conflict of interest: The authors declared no potential conflicts of interests with respect to research, authorship and/or publication of the article.

Acknowledgment: The authors hereby would like to thank all the staff of the neurosurgery department, from the reception in the department to the operating room, who combined kindness, professionalism and follow-up of our patient. The authors also do not forget to express their gratitude to the radiologists for their precious collaboration.

Sanan A, Haines SJ (1997) Repairing holes in the head: a history of cranioplasty. Neurosurgery 40(3):588–603
Echeverría y Pérez E, Priego Blancas RB, Díaz Aguirre CM (2009) y col. Diferentes aplicaciones de los implantes aloplásticos elaborados por metilmetacrilato y silicón [Different applications of alloplastic implants made of methyl methacrylate and silicone]. Rev Cir Plástica. 2009;19(1–3):51–56
Toledo JA, Re MS, Canullo ML, Morel A, Garrote MNJ (2015) Complicaciones en craneoplastias:hueso autólogo criopreservado vs. polimetilmetacrilato. Análisis retrospectivo de 63 pacientes [Complications in cranioplasties: autologous bone cryopreserved vs. Polymethylmethacrylate. Retrospective analysis of 63 patients]. Rev Argent Neurocir 29:80–83
Lindner D, Schlothofer-Schumann K, Kern BC, Marx O, Müns A, Meixensberger J (2017) Cranioplasty using custom-made hydroxyapatite versus titanium: a randomized clinical trial. J Neurosurg 126(1):175–183
Vougioukas VI, Hubbe U, van Velthoven V, Freiman TM, Schramm A, Spetzger U (2004) Neuronavigation-assisted cranial reconstruction. Neurosurgery 55(1):162–167
Baldia M, Sharma SA, Prabhu K, Koshy S (2017) Cost effective, technically simpler, and aesthetically promising cranioplasty in developing countries. Neurol India 65(3):660–663
Gopal S, Rudrappa S, Sekar A, Preethish-Kumar V, Masapu D (2021) Customized and Cost-Effective 3D Printed Mold for Cranioplasty: India's First Single Center Experience. Neurol India 69(3):611–617
Borni M, Abdelmouleh S, Taallah M, Blibeche H, Ayadi A, Boudawara MZ (2024) A case of pediatric primary osteolytic extradural and complicated hydatid cyst revealed by a skull vault swelling. Child's Nerv system: ChNS : official J Int Soc Pediatr Neurosurg 40(2):335–343
Baumeister S, Peek A, Friedman A, Levin LS, Marcus JR (2008) Management of postneurosurgical bone flap loss caused by infection. Plast Reconstr Surg 122(6):195e–208e
Sorolla JP, Obaid, Ibarra C, Arbulo D, Bautista A, Wisnea P, Cabello R, Fontbona M (2014) Expansores tisulares en reconstrucción de defectos craneofaciales: estudio multicéntrico retrospectivo [Tissue expansion in reconstruction of craniofacial defects. Multicenter retrospective study]. Cirugía Plástica Ibero-Latinoamericana 40(4):413–420
Rivas León B, Ramos N, Ortiz R, López JB, Gómez Mendoza FF (2010) Colgajo prefabricado occipital para cobertura de exposición ósea craneal [Prefabricated occipital flap to cover craneal bone exposition]. Cirugía Plástica Ibero-Latinoamericana 36(1):87–92
Flores-Lima G, Lovo Iglesias E (2010) Reconstrucción craneofacial compleja: malla de titanio, hueso autólogo preservado en óxido de etileno y reconstrucciones tridimensionales en polimetilmetacrilato (HTR-PMI) [Complex craneofacial reconstruction: titanium mesh, autologous bone preserved in ethylene oxide and tridimensional polimetilmetacrilate implants (HTR-PMI)]. Cirugía Plástica Ibero-Latinoamericana 36(1):31–36
Bowers CA, Riva-Cambrin J, Hertzler DA 2nd, Walker ML (2013) Risk factors and rates of bone flap resorption in pediatric patients after decompressive craniectomy for traumatic brain injury. J Neurosurg Pediatr 11(5):526–532
Borni M, Souissi G, Taallah M, Abdelmouleh S, Ayadi A, Boudawara MZ (2024) Early postoperative intra-axial dissemination of a pediatric extradural and complicated hydatid cyst. Child's Nerv system: ChNS : official J Int Soc Pediatr Neurosurg 40(2):321–325
Torres-Criollo L, Fernández-Martínez R, Saquicela-Espinoza A, Ramírez-Coronel AA, Ávila-Miranda C, Saltos-Moran SE (2021) Técnicas de Craneoplastía, luego de craniectomía descompresiva. Revisión de tres casos [Cranioplasty techniques after decompressive craniectomy. Review of three cases]. AVFT – Archivos Venezolanos De Farmacología Y Terapéutica, 39(8)
Morselli C, Zaed I, Tropeano MP, Cataletti G, Iaccarino C, Rossini Z, Servadei F (2019) Comparison between the different types of heterologous materials used in cranioplasty: a systematic review of the literature. J Neurosurg Sci 63(6):723–736
Akan M, Karaca M, Eker G, Karanfil H, Aköz T (2011) Is polymethylmethacrylate reliable and practical in full-thickness cranial defect reconstructions? J Craniofac Surg 22(4):1236–1239
van Gool AV (1985) Preformed polymethylmethacrylate cranioplasties: report of 45 cases. J Maxillofac Surg 13(1):2–8
Goh RC, Chang CN, Lin CL, Lo LJ (2010) Customised fabricated implants after previous failed cranioplasty. J Plast Reconstr aesthetic surgery: JPRAS 63(9):1479–1484
Stieglitz LH, Gerber N, Schmid T, Mordasini P, Fichtner J, Fung C, Murek M, Weber S, Raabe A, Beck J (2014) Intraoperative fabrication of patient-specific moulded implants for skull reconstruction: single-centre experience of 28 cases. Acta Neurochir 156(4):793–803
Marbacher S, Andereggen L, Erhardt S, Fathi AR, Fandino J, Raabe A, Beck J (2012) Intraoperative template-molded bone flap reconstruction for patient-specific cranioplasty. Neurosurg Rev 35(4):527–535
Kim BJ, Hong KS, Park KJ, Park DH, Chung YG, Kang SH (2012) Customized cranioplasty implants using three-dimensional printers and polymethyl-methacrylate casting. J Korean Neurosurg Soc 52(6):541–546
Katsikogianni M, Missirlis YF (2004) Concise review of mechanisms of bacterial adhesion to biomaterials and of techniques used in estimating bacteria-material interactions. Eur Cells Mater 8:37–57
Lee SC, Wu CT, Lee ST, Chen PJ (2009) Cranioplasty using polymethyl methacrylate prostheses. J Clin neuroscience: official J Neurosurgical Soc Australasia 16(1):56–63
Selvam MM, Nandini Y, Gupta RH (2020) Transcending Autologous Cranioplasty Neurol India 68(1):71
Binhammer A, Jakubowski J, Antonyshyn O, Binhammer P (2020) Comparative Cost-Effectiveness of Cranioplasty Implants. Plastic surgery. (Oakville Ont) 28(1):29–39
Parthasarathy J (2014) 3D modeling, custom implants and its future perspectives in craniofacial surgery. Annals maxillofacial Surg 4(1):9–18
Shim J-H, Yoon M-C, Jeong C-M, Jang J, Jeong S-I, Cho D-W, Huh J-B (2014) Efficacy of rhBMP-2 loaded PCL/PLGA/β-TCP guided bone regeneration membrane fabricated by 3D printing technology for reconstruction of calvaria defects in rabbit. Biomed Mater 9(6):065006

No competing interests reported.

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You are reading this latest preprint version

Low-cost acrylic cranioplasty using an implant cast on a pre-printed 3D polylactic acid model in a child with a complicated osteolytic extradural hydatid cyst

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