Medicinsko svrdlo s protočnim hlađenjem otvorenoga tipa u koštano-zglobnoj kirurgiji

doctoral thesis

• Title (english): Medical drill with open type internal cooling in bone and joint surgery
• Author: Tomislav Bruketa
• Mentor: Goran Augustin (mentor)
• Committee member: nije dostupno (član povjerenstva)
• Granter: University of Zagreb; School of Medicine; Zagreb
• Defense date and country: 2019-07-02, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Clinical Medical Sciences
• Universal decimal classification (UDC): 61 - Medical sciences

Abstract

Uvod i svrha rada. Bušenje kosti uzrokuje porast temperature na mjestu kontakta svrdla i kosti. Temperatura veća od 47°C može dovesti do termičke osteonekroze. Cilj istraživanja je ispitati kako svrdlo od medicinskog čelika sa sustavom unutarnjeg hlađenja otvorenog tipa utječe na maksimalnu temperaturu na mjestu bušenja kod svrdla različite istrošenosti. Također je ispitivana čvrstoća svrdla obzirom na izmjene potrebne za sustav unutarnjeg hlađenja. Ispitivani su utjecaj rashladne tekućine na intramedularni tlak, distribucija rashladne tekućine za vrijeme bušenja te specifičnosti sterilizacije takvog svrdla. -----
Materijali i metode. Za potrebe istraživanja kroz standardno svrdlo od medicinskog čelika promjera 4.5 mm, postupkom elektroerozije, napravljen je kanal za protok rashladne tekućine. Zbog izmjenjene strukture svrdla napravljena je eksperimentalna analiza tehničkih svojstava i analiza konačnih elemenata. Potom su provedena mjerenja porasta temperature na mjestu bušenja kosti sa svrdlom s unutarnjim protočnim hlađenjem s različitim stupnjem istrošenosti, zatim mjerenja intramedularnog tlaka tijekom bušenja, radiološkim slikama prikazana je distribucija rashladne tekućine intramedularno, te je provedeno ispitivanje učinkovitosti sterilizacije svrdla s sustavom unutarnjeg hlađenja otvorenog tipa. -----
Rezultati. Eksperimentalnom analizom tehničkih svojstava i analizom konačnih elemenata dokazano je da je modifikacija svrdla nema utjecaja na čvrstoću svrdla u kliničkim uvjetima. Maksimalne postignute temperature na mjestu bušenja pomoću svrdla s protočnim hlađenjem bile su manje od kritične temperature bez obzira na stupanj istrošenosti svrdla, dok su temperature kod svrdla bez hlađenja bile više od kritične. Rashladna tekućina koja ulazi u intramedularni kanal tijekom bušenja nema utjecaja na intramedularni tlak, niti se nakon bušenja širi po intramedularnom kanalu već ostaje samo u provrtu. Svrdlo sa sustavom unutarnjeg hlađenja otvorenog tipa zahtijeva produljeno vrijeme ciklusa sterilizacije. -----
Zaključak. Svrdlo sa sustavom unutarnjeg protočnog hlađenja otvorenog tipa značajno snižava maksimalnu temperaturu na mjestu kontakta svrdla i kosti bez obzira na stupanj istrošenosti. Takvo svrdlo moguće je izraditi od medicinskog čelika kako bi zadovoljavalo standarde za korištenje u medicini te ga je moguće adekvatno sterilizirati za ponovnu upotrebu. Rashladna tekućina koja se koristi tijekom bušenja nema utjecaja na intramedularni tlak.
Svrdlo od medicinskog čelika sa sustavom unutarnjeg protočnog hlađenja otvorenog tipa sigurno je za upotrebu u zahvatima u koštano-zglobnoj kirurgiji te je upotrebom istog moguće u potpunosti izbjeći nastanak termičke osteonekroze.

Abstract (english)

Background and aims: Drilling of the bone causes a temperature rise at the point of bone and drill contact. A temperature higher than 47°C can lead to thermal osteonecrosis. The aim of this research was to examine how stainless steel medical drill with open type cooling system affects the maximum temperature at the drilling site with drills of different degree of wear. Drill strength was also studied with regard to the changes required for the system for internal cooling. The influence of coolant on intramedullary pressure, distribution of coolant during drilling and specificity of sterilization of such drill was studied. -----
Methods and materials: For this research, through a standard 4.5 mm medical steel drill, with an electro-erosion process a channel was created. Due to the modification of the drill structure, experimental analysis of the technical properties and analysis of the finite elements was made. Afterwards, measurements of temperature increase at the point of drilling with a drill with open type internal cooling with different degree of wear were performed, also intramedullary pressure during drilling was measured. Intramedullary coolant distribution was showed with X-ray images. A study was carried out on sterilization efficiencies of drill bits with open type internal cooling system. Results: Experimental analysis of technical properties and analysis of finite elements proved that drilling modification has no effect on drill strength in clinical conditions. The maximum achieved temperatures at the drilling site with the open type internal cooling drills were less than critical regardless of the degree of wear of the drill while the temperatures of the drills without cooling were more than critical. Coolant fluid, entering the intramedullary channel, during drilling, has no effect on intramedullary pressure. During and after drilling coolant does not expand into the intramedullary channel but only remains in the bore. An open type internal cooling drill requires a prolonged cycle of sterilization cycles. -----
Conclusion: The open type internal cooling drill significantly reduces the maximum temperature at the point of bone and drill contact regardless of the degree of drill wear. Such a drill can be made of medical steel to meet standards for use in medicine and can be adequately sterilized for reuse. The coolant used during drilling does not affect the intramedullary pressure. The stainless steel medical drill with open type internal cooling is safe to use in bone and joint surgical procedures and is capable to avoid the formation of thermal osteonecrosis completely.

• Keywords: medicina
• Keywords (english): medicine
• Language: croatian
• URN:NBN: urn:nbn:hr:105:892559
• Study programme: Title: Biomedicine and Health Sciences; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje biomedicine i zdravstva (doktor/doktorica znanosti, područje biomedicine i zdravstva)
• Type of resource: Text
• Extent: 110 str.
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-05-05 08:32:18