Drilling around the corner: a comprehensive literature review of steerable bone drills

Abstract

Introduction: Orthopedic procedures often require drilling of tunnels through bone, for instance for the introduction of implants. The currently used rigid bone drills make it challenging to reach all target areas without damaging surrounding anatomy. Steerable bone drills are a promising solution as they enable access to larger volumes and the creation of curved tunnels thereby reducing the risk of harm to surrounding anatomical structures.

Method: This review provides a comprehensive overview of steerable bone drill designs identified in patent literature via the Espacenet database and in scientific literature accessed via the Scopus data base. A Boolean search combined with pre-set inclusion criteria returned 78 literature references describing a variety of drill designs.

Results: These drill designs could be categorized based on how the drilling trajectory was defined. Three methods to influence the drilling trajectory were identified: (1) the device (57% of the sources), (2) the environment (15% of the sources): the path is defined based on the tissue interaction forces with the surrounding bone or (3) the user defines the drilling trajectory (28% of the sources).

Discussion: The comprehensive overview of steerable drilling methods provides insights in the possibilities in drill design and may be used as a source of inspiration for the design of novel steerable drill designs.

Keywords: bone drilling; design; mechanical design; orthopedics; steerable drilling.

Figure 1

Overview of (orthopedic) procedures where the use of steerable bone drills can provide advantages, including implant placement, ligament reconstruction, fracture fixation and bone harvesting. Illustration adapted from Servier Medical Art by Servier (https://smart.servier.com/), licensed under a Creative Commons Attribution 3.0 Unported License.

Figure 2

Overview of the three identified steering methods utilized by steerable bone drills: (1) device-defined, (2) environment-defined, and (3) user-defined steering.

Figure 3

Steerable bone drills in which the drilling trajectory is defined by the device comprising a drill bit (yellow), a drive shaft (blue), an outer shaft (green) and a means to steer the drill bit (red). (A) Drill comprising two curved arms (red) with a drill tip (yellow) to create a curved tunnel. Illustration adapted from (15) licensed under CC BY 4.0, https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2012024162&_cid=P11-M8N9FZ-94086-1. (B) Drill comprising two individual drill bits to create a curved tunnel. Illustration adapted from (21) licensed under CC BY 4.0, https://patentscope.wipo.int/search/en/detail.jsf?docId=WO1991011961&_cid=P11-M8NA9I-18892-1. (C) Drill with an external guide (red) that bends the drill bit, actuated with a flexible drive shaft (blue), to reach a desired entry point. Illustration adapted from (36) licensed under CC BY 4.0, https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2018058126&_cid=P11-M8NAAU-19901-1. (D) Drill using an external guide (red) to create curved tunnels. Illustration adapted from (41) licensed under CC BY 4.0, https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2008031245&_cid=P11-M8NA58-15412-1. (E) Drill using an internal guide wire (red) over which the tubular flexible drill (blue and yellow) is advanced. Illustration adapted from (44) licensed under CC BY 4.0, https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2019161436&_cid=P11-M8NA3E-14038-1. (F) Drill comprising two concentric tubes that can be rotated and translated with respect to each other such that the curved innertube (red) can be used to steer the drill. Illustration adapted from (57) licensed under CC BY 4.0, https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2001060262&_cid=P11-M8NA0W-11964-1.

Figure 4

Steerable bone drills in which the drilling trajectory is defined by the environment comprising a drill bit (yellow) and a flexible drive shaft (blue). (A) Bone drill with an eccentric drill bit aiding bending of the drill. Illustration adapted from (64) licensed under CC BY 4.0, https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2015069675&_cid=P11-M8NADG-22192-1. (B) Bone drill with a flexible drill shaft (blue) comprising interlocking teeth. Illustration adapted from (68) licensed under CC BY 4.0, https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2021050046&_cid=P11-M8NAO5-30611-1. (C) Drill comprising two stacked leaf springs (blue) that allow for planar bending of the drill bit (yellow). Illustration based on bone drill developed by de Kater et al. (71).

Figure 5

Steerable bone drills in which the drilling trajectory is defined by the user comprising a drill bit (yellow), a drive shaft (blue), an outer shaft (green) and a means of steering (red). (A) Steerable bone drill comprising two spines that allow articulation of the drill bit to steer the drill in the desired drilling trajectory. Illustration adapted from (72) licensed under CC BY 4.0, https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2014185887&_cid=P11-M8NB78-47390-1. (B) Steerable drill using a steering cable (red) that can be pulled to steer the drill in the desired direction. Illustration adapted from (79) licensed under CC BY 4.0, https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2018160269&_cid=P11-M8NB80-48077-1. (C) Drill with a drill tip comprising a helical spring-like outer shaft (green) that can be bend by tensioning the steering cable (red). Illustration adapted from (87) licensed under CC BY 4.0, https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2010135606&_cid=P11-M8NB8X-48777-1. (D) Bone drill using an internal guide (red) as well as a drive shaft (blue) with a conical end (red) that can be tensioned to change the drill tip orientation. Illustration adapted from (61) licensed under CC BY 4.0, https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2018075925&_cid=P11-M8NBAW-50313-1. (E) Steerable bone drill comprising two concentric flexible tubes that can be translated and rotated with respect to each other to articulate the drill tip through the eccentric drive shaft (blue). Illustration adapted from (89) licensed under CC BY 4.0, https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2023023634&_cid=P11-M8NBBN-50812-1.

Figure 6

Overview of the included literature. (A) Application area of the steerable bone drills described in the included scientific and patent literature. (B) Temporal distribution of the publication date of the included literature.