Background Bone fracture treatment usually involves restoring of the fractured parts to their initial position and immobilizing them until the healing takes place. Drilling of bone is common to produce hole for screw insertion to fix the fractured parts for immobilization. Orthopaedic drilling during surgical process causes increase in the bone temperature and forces which can cause osteonecrosis reducing the stability and strength of the fixation. Methods A comprehensive review of all the relevant investigations carried on bone drilling is conducted. The experimental method used, results obtained and the conclusions made by the various researchers are described and compared. Result Review suggests that the further improvement in the area of bone drilling is possible. The systematic review identified several consequential factors (drilling parameters and drill specifications) affecting bone drilling on which there no general agreement among investigators or are not adequately evaluated. These factors are highlighted and use of more advanced methods of drilling is accentuated. The use of more precise experimental set up which resembles the actual situation and the development of automated bone drilling system to minimize human error is addressed. Conclusion In this review, an attempt has been made to systematically organize the research investigations conducted on bone drilling. Methods of treatment of bone fracture, studies on the determination of the threshold for thermal osteonecrosis, studies on the parameters influencing bone drilling and methods of the temperature measurement used are reviewed and the future work for the further improvement of bone drilling process is highlighted.

Drilling of bone: A comprehensive review.

Bone drilling causes an increase in bone temperature, and a temperature above 47°C is critical because it causes thermal bone necrosis. Thermal osteonecrosis is common with the drill diameter of ≥4.5 mm without cooling. The aim of this study was to determine the increase of bone temperature during drilling using newly contructed two-step and internally cooled drills. An experiment was set up according to a central composite design. An internally cooled drill (3.4 mm and 4.5 mm) and a two-step drill (2.5/3.4 and 3.4/4.5 mm) were used in combination with feed rates of (0.02, 0.04, 0.10, 0.16 and 0.18 mm/rev) and cutting speeds (1.18, 10.68, 33.61, 56.55 and 66.05 m/min) with and without cooling with water of 24°C. Bone temperatures were measured with thermocouples. Drilling was performed on pig diaphyses with a three-axis mini milling machine. Bone temperatures in all combinations of parameters with internal cooling were below the critical 47°C (p = 0.05). The highest temperatures were detected using a 4.5-mm drill (40.5°C). A statistically significant effect other than cooling was found with the drill diameter and feed. A drill diameter of 3.4 mm with internal cooling developed a maximum temperature of 38.5°C and without cooling 46.3°C. For the same conditions a drill with diameter of 4.5 mm reached temperatures of 40.5°C and 55.7°C, respectively. The effect of feed rate is inversely proportional to the increase in bone temperature. With the feed rate 0.16 mm/rev, temperature was below critical even using the 4.5-mm drill (46.4°C, p = 0.05). Using the 3.4-mm drill all temperatures were below critical (46.2°C, p = 0.05). The two-step drill compared to a standard drill with the same diameter did not show statistical differences in maximum bone temperatures for all combinations of parameters (p = 0.05). A two-step drill does not have any advantages over a standard twist drill of the same diameter. An internally cooled drill causes a significantly smaller increase of bone temperature during drilling with water of 24°C. An internally cooled drill is currently the 'ideal' drill for traumatology/orthopaedics because it produces the smallest increase in bone drilling temperature. If internal cooling is used the regulation of other drilling parameters is of no importance.

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Temperature changes during cortical bone drilling with a newly designed step drill and an internally cooled drill.

Introduction: Patients with complex medical and surgical problems often travel great distances to prestigious university medical centers in search of solutions and in some cases for nothing more th

A review of translational medicine. The future paradigm: how can we connect the orthopedic dots better?

Bone cutting is an important procedure in most surgery operations; therefore, understanding the mechanism by which the chip forms is important to design tools for optimising the surgery process. However, only very few studies to address this issue exist. In this paper, a transition from shear cutting, shear-crack cutting and fracture cutting modes with the increase of uncut chip thickness in orthogonal bone cutting was presented. To address these phenomena, a fracture mechanics based cutting model was proposed for the chip formation and cutting process. The influence of the anisotropy of bone to the orthogonal cutting was studied in reference to chip formation and thus, considered in the model to explain the chip morphologies in different cutting directions relative to the bone fibres (i.e. osteon). The experimental result shows to be consistent well with the proposed model yielding a maximum error of predicted transition uncut chip thickness of 10%. On the other hand, analysis of surface morphology revealed that significant differences exist in material damage mode related to the cutting mode and direction. Moreover, the proposed bone orthogonal cutting mechanism was also validated by the cutting force analysis from both static and dynamic components points of view. Based on this study, a maximum uncut chip thickness in a unique anisotropic material as bone to guide the selection of more advanced cutting process (e.g. drilling, milling and sawing) was proposed.

On chip formation mechanism in orthogonal cutting of bone

Experimental analysis of drilling process in cortical bone.

Cortical bone drilling and thermal osteonecrosis

Day surgery is a term that refers to performing an operation under anesthesia without needing to stay in the hospital for more than 24 hours. Day surgery has many advantages over surgery that involves a multiple-day hospital stay. Anesthesia for day surgery must have a rapid onset of action, a rapid cessation of action, and be free of, or have minimal side effects. For many years, general anesthesia was believed to be the anesthesia of choice for day surgery due to the delayed onset of local anesthetic after spinal anesthesia, a much longer duration of motor function recovery after surgery with spinal anesthesia compared to general anesthesia, and a more frequent incidence of side effects with spinal anesthesia, such as urinary retention or post-puncture headache. However, with the discovery of new, shorter-acting local anesthetics, and the use of smaller-diameter spinal needles, spinal anesthesia is becoming an equivalent anesthetic option for day surgery, if not a better one. Our early expiriences with spinal anesthesia in day surgery are excellent.

/pdf/spinal-anesthesia-in-day-surgery-early-experiences-518dej2j.pdf

Slaven Babic

Papers

Cortical bone drilling and thermal osteonecrosis

Temperature changes during cortical bone drilling with a newly designed step drill and an internally cooled drill.

Spinal anesthesia in day surgery – early experiences