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Uvod. Vstavitev pedikularnih vijakov s prostoročno tehniko je povezana z zapleti zaradi nepravilne postavitve vijaka, predvsem s poškodbo in prebojem pedikla. To tveganje je mogoče delno zmanjšati z uporabo diaskopije. Natančnost vstavitve vijakov poveča navigacija, katere glavne pomanjkljivosti so visoka cena, daljši čas operativnega posega in večje tveganje za okužbo med posegom. Alternativo, ki bi lahko odpravila večino navedenih pomanjkljivosti, predstavlja metoda hitre izdelave prototipov, s katero je mogoče izdelati posamezniku prilagojene vodilne šablone, ki omogočajo optimalno postavitev vijakov. Od leta 1998 je bilo izvedenih nekaj raziskav, v katerih so z uporabo vodilnih šablon predvsem na kadavrih in tudi klinično relativno uspešno vstavljali pedikularne vijake. Najnatančnejšo vstavitev vijakov so zagotavljale šablone, ki so se kot odlitek prilegale dorzalnim delom hrbtenice in so omogočale vstavljanje le enega vijaka hkrati. Ob tem je bila za natančno namestitev šablone potrebna obsežna preparacija mehkih tkiv. Pri nas smo izvedli klinično raziskavo, v okviru katere smo izdelali šablone, ki ne zahtevajo obsežne preparacije mehkih tkiv in omogočajo hkratno vstavljanje vijakov na več nivojih. Metodo smo primerjali s prostoročno tehniko pod RTG-nadzorom. V raziskavo smo prvič vključili tudi križnično hrbtenico. Namen. Razvoj večnivojske vodilne šablone za vstavitev pedikularnih vijakov v ledveno in križnično hrbtenico, ki bo omogočala optimalno postavitev pedikularnih vijakov in bo natančnejša od prostoročne tehnike pod RTG-nadzorom. Preiskovanci in metode. V prospektivni klinični raziskavi primerov s kontrolami smo analizirali 24 preiskovancev, predvidenih za zatrditev dveh ali več vretenc na ledvenem in prvem križničnem nivoju. V vsaki skupini smo vstavili 72 vijakov. Pri 11 osebah smo uporabili 17 večnivojskih šablon. Izdelali smo jih individualno na podlagi predoperativnih CT-posnetkov s postopkom selektivnega laserskega sintranja, tako da so natančno nasedale na fasetne sklepe. Šablono so sestavljali kanali, ki so pod optimalnim kotom usmerjali pedikularni vijak natančno skozi središče pedikla. V skupino, predvideno za vstavitev pedikularnih vijakov s prostoročno tehniko pod RTG-nadzorom, smo vključili 13 oseb. Operativni poseg smo v obeh skupinah izvedli v enakih pogojih, merili smo celotni čas posega in čas trajanja efektivnega RTG-sevanja. Po operativnem posegu smo posneli CT, na podlagi katerega smo opravili meritve in statistično analizo prebojev pediklov ter teles vretenc za obe skupini. Po istem principu smo analizirali relativni odmik in odmik ter odklon vijakov od optimalnega položaja. Ocenili smo natančnost postopka izdelave in uporabe šablone. Za obe skupini smo primerjali čas trajanja efektivnega RTG-sevanja in čas celotnega operativnega posega. Rezultati. Skupna pojavnost preboja pediklov in vretenc je bila pri uporabi vodilne šablone (6/72) statistično značilno nižja (p < 0.001) kot pri kontroli (29/72). Relativni odmik (p = 0.033), sredinski odklon (p = 0.003) in trajanje efektivnega sevanja na posamezen vijak (p = 0.02) so bili značilno manjši pri skupini z uporabo šablon. Pri transverzalnem odmiku in odklonu ter sredinskem odmiku nismo izmerili statistično značilnih razlik med obema skupinama. Prav tako ni bilo značilnih razlik pri izbiri dolžine vijakov in pri trajanju operativnega posega na nivo. Za nivo S1 smo ugotovili statistično značilno razliko v skupnem številu prebojev pedikla in vretenca (šablona: 1/10, kontrola: 10/16, p = 0.014). Značilnih razlik ni bilo pri izoliranem številu prebojev pedikla, v sredinskem odmiku, transverzalnem odmiku in odklonu, relativnem odmiku ter razliki v dolžini vijakov. Pri uporabi šablone za nivo S1 smo ugotovili značilno manj sredinskega odklona (p = 0.003) in števila prebojev vretenca (p = 0.037). 19 od 72 (26 %) vijakov v celotni skupini z uporabo vodilnih šablon je bilo napačno postavljenih za nivo S1 je bilo takih vijakov 8 od 10 (80 %). Zaključki. Upora Introduction. Pedicle screw placement using free hand technique has a high risk of screw misplacement connected with noticeable incidence of pedicle perforation and violation. Perforation risk can be partially reduced with intra-operative fluoroscopy. A highly accurate screw placement method is the method of navigation with certain disadvantages like high price, longer operation time and higher infection rate. The alternative to solving most of the issues could be the rapid prototyping technology. This technology makes it possible to manufacture patient specific drill guide templates that enable optimal pedicle screw placement. Since 1998, many studies have featured relatively successful implantations of pedicle screws through the use of drill guide templates, though mostly on cadavers, but also in clinical cases. The most accurate template was one that precisely fitted into dorsal elements of the spine and allowed placement of only one screw in same session. Unfortunately, precise stripping of the soft tissues was required. We performed a clinical study involving the manufacture of templates for the lumbo-sacral region that enable simultaneous multiple-level screw implanting without extended soft tissue removal. The template has been compared with a control group where screws were implanted using free hand technique under fluoroscopy supervision. For the first time also a spinal level S1 was included in the study. Aim. Development of a multi-level drill guide template that enables optimal positioning of pedicle screws and is also more accurate in comparison to free hand technique under fluoroscopy supervision. Materials and Methods. A randomized clinical trial was performed on 24 patients. In lumbar and sacral spine 72 screws were implanted for each group. On 11 patients, 17 templates were applied. Drill guide templates were manufactured individually according to preoperative CT-scans using selective laser sintering technology. Templates had precisely fitted into facet joints allowing a lock and key mechanism and had trajectory holes that have directed pedicle screws trough the center of pedicles. During the operation procedure the operation time and radiation exposure time was measured for both groups. A statistical analysis for pedicle and vertebra perforation was performed according to postoperative CT-scans. In the same fashion the analysis of displacement, deviation, relative displacement of screws, operation procedure time and radiation exposure time for implanted screws was performed for both groups. Also a drill guide template manufacture and application error rate has been estimated. Results. The incidence of pedicle and vertebra perforation was significantly reduced (p < 0.001) in a drill guide template group (6/72) in comparison to control (29/72). Relative displacement (p = 0.033), sagittal deviation (p = 0.003) and radiation exposure time by implanted screw (p = 0.02) were significantly lower in the trial group. The sagittal displacement and transversal deviation and displacement were lower, but statistically insignificant. No significant difference has been observed in screw length difference and operation procedure time. A statistically significant difference for the first sacral level was observed for pedicle and vertebra perforation (drill guide group: 1/10, control: 10/16, p = 0.014). The pedicle perforation, sagittal displacement, transversal deviation and displacement, relative displacement and screw length difference were also statistically insignificantly different. For spinal level S1 sagittal deviation (p= 0.003) and number of vertebral perforations (p = 0.037) were significantly lower for the trial group. Pedicle screw misplacement rate in the whole drill guide template group was 19/72 (26 %) misplacement rate for the first sacral level reached 8/10 (80 %). Conclusions. Drill guide templates have turned out to be a reliable solution that significantly reduces pedicle and vertebra perforation incidence and complications related to it in comparison with the free hand technique under fluorosco |
