[Clinical studies of transpedicular system using TiNi rod with functionally optimal rigidity].

Transpedicular metal systems are very widely applied in surgical treatment of spinal pathology. Recently TiNi constructions were introduced into practice. This material is characterized by shape memory, superior elasticity and cyclic durability. Adequacy of mechanical interactions of tissues and TiNi-based alloys allows to suggest that TiNi systems are more physiological and functional in comparison with steel and titanium alloys. This enabled development of transpedicular TiNi system with good safety and stability properties in combination with physiologic compatibility and high functional value of TiNi connections. We performed computer modeling of different spine lesions treated by transpedicular systems using ANSYS program kit. Statistic and cyclic tests of transpedicular systems were made using test machine 'Terotest' according to international standards. Results of studies allowed to formulate guidelines for application of transpedicular systems with different level of rigidity in treatment of injuries and degenerative lesions of the spine. The authors performed 53 operations in patients with lesions of lower-thoracic and lumbar spine using TiNi rod with functionally optimal rigidity and obtined good postoperative results.

[Correction of neurological complications after transpedicular stabilization of the spine].

Nowadays transpedicular fixation systems have gained great priority in stabilization of thoracic and lumbar spine. But implantation of the system may cause iatrogenic complications due to extrapedicular insertion (malposition) of screws. Present work is devoted to analysis of neurologic disturbances of screw malposition in the prospective study of 44 consecutive patients. Patients had complains which could be attributed to mistakes in implantation of TPF system. After detailed examination we created a group of 8 patients who had compression of spinal cord and radices due to inadequately implanted TPF system (5 male and 3 female patients, age range 27-63 (median 42)). According to malposition of screws we divided patients into 3 groups: medial malposition (3 patients); lateral (2 patients); and 2 patients with inferior-lateral malposition. 1 patient had both medial and lateral malposition of screws. On the basis of results of treatment we suggested management protocol for complications due to mistakes in implantation of TPF.

[Experimental and clinical substantiation of the functional transpedicular stabilization of the vertebral column]. / Eksperimental'no-klinicheskoe obosnovanie funktsional'noi transpedikuliarnoi stabilizatsii pozvonochnika.

Metallic construction for transpecular stabilization (transpedicular constructions T-TPC). Titanium nickelide (TiNi) alloys have come into existence in the surgical treatment of diseases of the vertebral column and spinal cord. The properties of these alloys are the storage of a shape, superelasticity, and cyclic longevity. The adequate mechanical behavior of live tissues and TiNi-based alloys suggests that metallic constructions made from TiNi are more physiological and functional than those made from steels and titanium alloys. The foregoing makes it possible to consider the design of metallic constructions to be promising for transpedicular spinal stabilization involving the latter's reliability and stability with the physiological and functional capacities of TiNi fixing arms. The study performed computer-assisted simulation of surgical treatment for different spinal diseases by using TPC by means of the programme package ANSYS and statistical and cyclic studies of TPC up to the international standards on a Terotest testing machine. The experimental findings were used to formulate recommendation to use TPC of varying rigidity to treat spinal injuries and diseases. Eight operations were performed to treat patients with diseases of the lower thoracic and lumbar parts of the vertebral column, by using TiNi rod of the optimum rigidity, which yielded good clinical results.