Such material was used in the past but before 2008 it was available only as standardized plates. Currently, it can be also produced as individually shaped implants.

The authors give their definition of very large cranial defects and present their experience with this cranioplastic method in such defects. The authors collected data on 11 cases of patients with very large cranial defects, from a total of 156 cases, operated on in 5 Polish neurosurgical departments. The necessary implants were prepared for individual patients according to the data provided by a computed tomography examination and with the use of computer aided machining. All defects were larger than 120 sqcm (129 to 178 sqcm) and exceeded 1/4 of the calvaria area. Patients were operated between 2008 to 2012. In all patients, a very good aesthetic result and correct skull reconstruction was achieved. The follow up time in all cases exceeded 1 year and reached 4 years in 1 case. No complications were noted. The advantages and limitations of this method of cranioplasty are discussed below. Individually pre-shaped polypropylene - polyester knitwear prostheses are a good alternative to existing cranioplasty methods, particularly in very large cranial defects ¹⁾.