Cranial implants

Cranial defects can be caused by injury, infection, or tumor invasion. Large defects should be restructured to protect the brain by using cranial implants. The conventional method is to cover the defect with bone cement. Nowadays, custom-made implants designed for the individual patient are available. Rapid prototyping techniques and medical-grade plastics allow surgeons to repair large holes in skulls. 

Center is currently fabricating customized cranial implants for injured soldiers, with titanium implants customized for a specific patient s cranial profile and injury. In the third paper, Andrew Christensen (Medical Modeling Inc.) discusses medical applications of additive manufacturing. 

A rapidly growing use in the medical field is for surgical implants as either bone plates and screws, joint replacements, or for the repair of cranial injuries. Here, titanium and its alloys have the advantages of complete compatibility with body fluids, low density, and low modulus. Applications also exist in dentistry. 

Bleeding during the implantation procedure is controlled by umbilical tapes around the cranial and caudal veins and by purse string sutures at the implantation sites. The pericardial incision and the chest is closed by sutures and the transducer wires are connected to the recording equipment. 

However, because a continuous infusion is required, implantable pumps containing a very concentrated solution of baclofen are used to avoid frequent refills. Inadvertent subarachnoid bolus administration of a concentrated solution will produce cranial spread of baclofen within the CSF, resulting in cerebral effects. This is most hkely to occur when a new catheter or pump is implanted or during surgical revision of a catheter or implantable pump in cases of malfunction. A report of coma after implantation of a baclofen pump in five out of nine consecutive children illustrates this (3). The authors suggested that these children should be monitored in the recovery room for 5 hours postoperatively, in order to cover both the peak effect of any baclofen bolus and the additive effects of other perioperative CNS suppressants, such as opioids, benzodiazepines, or sedative antiemetics. In another report of transient coma after perioperative intrathecal bolus administration it was shown that the management of this complication can require admission to an intensive care unit (4). 

Rat cranial defect model showed almost complete bone healing across the defect [45] area, 12 weeks after implantation of the composite scaffolds... 

Synthetic materials based on hydroxyapatite are used as implants in ear, nose and throat surgery, facial and cranial rebuilding and in fracture healing. Dental uses include crowns, tooth capping, dentures and tooth implants [27,28,33]. 

Schiller, C., Rasche, C., Wehmdller, M., Beckmannc, F., Eufinger, H., Epple, M., and Weihe, S. (2004) Geometrically stmctured implants for cranial reconstmction made of biodegradable polyesters and calcium phosphate/ calcium carbonate. Biomaterials, 25 (7), 1239-1247. 

PDS demonstrated no acute or toxic effects on implantation, and thus has been used in a number of clinical applications ranging from suture materials to bone fixation devices. Johnson and Johnson Orthopedics provides an absorbable pin for fracture fixation, and bone pins have been introduced into the market under the names OrthoSorb and Ethipin, respectively, in the USA and Europe. In craniofacial applications, the structure of PDS has been examined clinically in cranial vault procedures with promising results. Advantages include the absence of observed intracranial translocation, acceptable aesthetic outcomes and low complication rates. Nevertheless,... 

The health care industry is capitalizing on new medical technologies based on loT that will both dramatically improve care and lower costs. There is a dramatic growth in medical devices that use wireless technologies, some implanted and some worn on the body, to control bodily functions and to measure an array of physiological parameters. For example, implanted devices with biosensors and actuators can control heart rhythms, monitor hypertension, provide functional electrical stimulation of nerves, operate as glaucoma sensors, and monitor bladder and cranial pressure [3]. Electronic textiles (E-Tex)-based WBSNs for noninvasive health care monitoring will be the most... 

Leiggener, C.S., Curtis, R., MiiUer, A.A., Pfluger, D., Gogolewski, S., Rahn, B.A., 2006. Influence of copolymer composition of polylactide implants on cranial bone regeneration. Biomaterials 27, 202—207. 

Ruhe, P.Q., Kroese-Deutman, H.C., Wolke, I.G., Spauwen, P.H., and lansen, [.A. Bone inductive properties of rhBMP-2 loaded porous calcium phosphate cement implants in cranial defects in rabbits. Biomaterials 25 2123-2132,2004. 

The cytotoxic, mutagenic, and sensitizing potential of the cranial plate was evaluated in a series of in-vitro and in-vivo studies. The poly(L-lactide) rivet/pins were not evaluated for biocompatibility because PLA containing devices have been shown to be biocompatible when implanted in animals and because of the long clinical history of safe use of various of PLA devices including bone screws and suture anchors. 

Tantalum is completely inert to body fluids and tissues. Bone and tissue do not recede from tantalmn, and this biocompatibility makes it an attractive material for body and dental implants. However, the superior strength and rigidity of stainless steel and titanimn and the castabUity of high-cobalt alloys have led to their greater use for prosthetic devices. Tantalmn has nevertheless been used for bone replacement and repair, for cranial repair plates, suture wire, and wire gauze for abdominal muscle support in hernia smgery. ... 

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