The invention relates to a drill system suitable for use in human medicine or veterinary medicine.

Medical drill systems are used in various medical fields, for example in bone surgery or dentistry, for making channels in bones, teeth or other types of tissue within the context of surgical treatments. For example, bone drills are used to produce drill channels in bones for receiving bone screws. In order to prevent nerve pathways or other sensitive regions close to a drill site from being damaged during the drilling operation, associated X-ray examinations are conventionally carried out before the drilling operation or during the drilling operation. Also known are dental drill systems which are equipped with an ultrasonic probe which is separate from a hand drill. With these systems, the drilling operation can regularly be interrupted and drills can be removed from the patient's mouth. The ultrasonic probe can then be brought to the drill site and the path of the drill channel that has already been produced can be checked.

The object of the invention is to provide a drill system suitable for use in human medicine or veterinary medicine, which allows damage to nerve pathways or other sensitive regions close to a drill site to be avoided simply and with high reliability.

The object is achieved by a medical drill system having the features of claim 1.

A medical drill system comprises a drill with a drilling head for receiving a drilling tool. The drill can be a surgical or dental drill which is designed to form drill channels in bones, teeth or other types of tissue. The drilling head is preferably equipped with an arrangement for releasably fixing the drilling tool to the drilling head, so that the drilling head can be connected to different drilling tools as required. The design of the drilling tool, that is to say the material and/or the form of the drilling tool, is/are preferably adapted to the type of tissue in which a drill channel is to be formed by means of the drill. The drill can further be provided with a drive unit, which is preferably configured to set the drilling tool connected to the drilling head in rotation in order to produce a drill channel. The drill of the medical drill system is further equipped with a measuring probe. The measuring probe has a transmitting unit which is configured to transmit measuring signals during a drilling operation. The measuring probe further comprises a receiving unit which is configured to receive during the drilling operation measuring signals reflected at tissue in the vicinity of a drill channel produced by means of the drilling tool. The measuring signals transmitted by the transmitting unit of the measuring probe are reflected differently by different types of tissue in the vicinity of the drill channel. For example, bones, blood vessels or nerve pathways can differ in terms of their properties of reflecting the measuring signals transmitted by the transmitting unit of the measuring probe. This manifests itself in the reflected measuring signals received by the receiving unit of the measuring probe. The transmitting unit and/or the receiving unit can comprise a plurality of individual transmitters or individual receivers, as required. It is important that the measuring probe can be operated during the drilling operation, that is to say during production of a drill channel by means of a drilling tool connected to the drilling head.

Finally, the medical drill system comprises a control unit which is configured to identify during the drilling operation different types of tissue in the vicinity of the drill channel produced by means of the drilling tool on the basis of the measuring signals transmitted by the transmitting unit of the measuring probe and also on the basis of the reflected measuring signals received by the receiving unit of the measuring probe. The control unit can be integrated into the drill or can be separate from the drill. In the medical drill system, the control unit can be used to monitor the vicinity of the drill hole in real time during the drilling operation. In particular, different types of tissue, such as, for example, bones, blood vessels or nerve pathways, can be distinguished from one another, so that it is possible to avoid bringing the drill channel undesirably close to a nerve pathway or another sensitive region. Injuries to the patient during surgery can thereby be prevented without having to interrupt the drilling operation or perform complex parallel monitoring of the drilling operation, for example by means of X-rays.

In a preferred embodiment of the medical drill system, the control unit is configured to calculate during the drilling operation a distance between the drill channel and a sensitive tissue region on the basis of the measuring signals transmitted by the transmitting unit of the measuring probe and also on the basis of the reflected measuring signals received by the receiving unit of the measuring probe. The sensitive tissue region can be, for example, a nerve pathway, a blood vessel or another tissue region which is not to be affected by the drill channel. In order to determine the distance between the drill channel and the sensitive tissue region, the control unit can calculate, for example, a time lag between a measuring signal transmitted by the transmitting unit of the measuring probe and the corresponding measuring signal reflected at the sensitive tissue region and received by the receiving unit of the measuring probe. By continuously monitoring the distance between the drill channel and the sensitive tissue region, it is possible to prevent the drill channel from coming too close to the sensitive tissue region and damaging it.

The medical drill system can further comprise a warning signal output unit. The control unit can further be configured to make the warning signal output unit give out a warning signal if, during the drilling operation, the distance calculated by the control unit between the drill channel and the sensitive tissue region falls below a first threshold. The warning signal output unit can be configured to give out an acoustic and/or an optical warning signal. For example, the warning signal output unit can be arranged in the region of a handle of the drill and thus be clearly visible to a user even during the drilling operation. The warning signal output unit can be in the form of a traffic light system with a green, an amber and a red lamp. As long as the drill channel is far enough away from the sensitive tissue region, the green lamp of the warning signal output unit can be illuminated, but if the drill channel comes closer to the sensitive tissue region, the amber lamp of the warning signal output unit can be switched on. Finally, the red lamp of the warning signal output unit can be switched on if the distance between the drill channel and the sensitive tissue region falls below the first threshold.

The control unit can further be configured to interrupt the operation of the drill if, during the drilling operation, the distance calculated by the control unit between the drill channel and the sensitive tissue region falls below a second threshold. With such a configuration of the medical drill system, damage to the sensitive tissue region can reliably be avoided. Interruption of the operation of the drill by the control unit can be achieved, for example, by the control unit transmitting to a drive unit of the drill a corresponding control signal by means of which the drive unit is rendered

inoperative. The second threshold is preferably smaller than the first threshold, so that a two-stage safety system can be obtained.

The first and/or the second threshold can in principle be predetermined values based, for example, on empirical values. For example, the first threshold can be 4 mm and the second threshold 2 mm. However, the medical drill system preferably comprises an input unit for manually entering the first and/or the second threshold. The possibility of specifying the first and/or the second threshold manually allows, for example, patient-specific particularities, such as, for example, age-related reduced bone density or osteoporosis of the patient, which require a greater "safe distance" between the drill channel and a sensitive tissue region, to be taken into account.

The transmitting unit of the measuring probe can be configured to transmit during the drilling operation first measuring signals in a direction substantially parallel to a drilling axis and second measuring signals in a direction substantially perpendicular to the drilling axis. The receiving unit of the measuring probe can correspondingly be configured to receive during the drilling operation the first and second measuring signals reflected at tissue in the vicinity of the drill channel. With such a configuration of the measuring probe, the vicinity of the drill channel in the region of its side walls and of its tip can be monitored. This allows the path of the drill channel to be guided particularly precisely, since both the distance of the drill channel side walls from a sensitive tissue region and the distance of the drill channel tip from a sensitive tissue region can be monitored during the drilling operation.

The drilling tool can have in the region of its tip a first opening for emission of the first measuring signals transmitted by the transmitting unit of the measuring probe. The drilling tool can further be provided in the region of a side wall with a second opening for emission of the second measuring signals transmitted by the transmitting unit of the measuring probe. Owing to the opening(s) provided in the drilling tool, the measuring signals transmitted by the transmitting unit of the measuring probe can be released in the vicinity of the drilling tool. Furthermore, the measuring signals reflected at tissue in the vicinity of the drilling tool can pass to the receiving unit of the measuring probe through the opening(s) provided in the drilling tool.

The measuring probe can be inserted into a first receiving channel which is formed in the drilling head and extends preferably substantially parallel to and in particular coaxially with the drilling axis. The measuring probe can be received in the first receiving channel in a releasable manner, so that it can be removed from the first receiving channel if required, for example for repair or cleaning purposes. The measuring probe can further be introduced into the first receiving channel in a slidable manner, so that the measuring probe can be brought to different positions in the first receiving channel for carrying out measurements during a drilling operation. Alternatively, however, it is also conceivable to integrate the measuring probe in a fixed manner into a first receiving channel formed in the drilling head. In addition or alternatively, the measuring probe can be inserted into a second receiving channel which is formed in the drilling tool and extends preferably substantially parallel to and in particular coaxially with the drilling axis. A measuring probe inserted into a second receiving channel formed in the drilling tool can be placed at a tip of the drilling tool and can therefore have a smaller measuring depth, that is to say a smaller depth of penetration of the measuring signals transmitted by the transmitting unit of the measuring probe into the tissue in the vicinity of the drill channel.

The measuring probe can be received in the second receiving channel in a releasable manner, so that it can be removed from the second receiving channel if required, for example for repair or cleaning purposes. The measuring probe can further be introduced into the second receiving channel in a slidable manner, so that the measuring probe can be brought to different positions in the second receiving channel for carrying out measurements during a drilling operation. Alternatively, however, the measuring probe can also be integrated into the drilling tool. Finally, it is conceivable to design the measuring probe itself as the drilling tool.

The measuring probe of the medical drill system can comprise an ultrasonic probe, in particular a Doppler ultrasonic probe, or can be in the form of an ultrasonic probe, in particular a Doppler ultrasonic probe.

Alternatively, however, it is also conceivable to equip the measuring probe of the medical drill system with an optical coherence tomography probe or to design it in the form of an optical coherence tomography probe. Optical coherence tomography probes are distinguished by a particularly small overall size and can consequently be fitted even into very small drills. Finally, it is also conceivable to equip the measuring probe with an ultrasonic probe and an optical coherence tomography probe.

The control unit of the medical drill system can comprise a memory in which there are stored reference values for the reflection of the measuring signals transmitted by the transmitting unit of the measuring probe by different types of tissue. The reference values stored in the memory of the control unit are preferably adapted to the form of the measuring probe. If the measuring probe comprises an ultrasonic probe, reference values for the attenuation of ultrasonic waves of a particular frequency by different types of tissue can be stored in the memory of the control unit, for example. Correspondingly, reference values for the attenuation of light waves of a particular frequency by different types of tissue can be stored in the memory of the control unit if the measuring probe comprises an optical coherence tomography probe.

The medical drill system can further be equipped with an image generation device which is configured to generate during the drilling operation a two-dimensional or three-dimensional real-time image of the vicinity of the drill channel on the basis of data provided by the control unit.

The medical drill system can further comprise a display device for displaying the realtime image generated by the image generation device. The drilling operation can thereby be monitored particularly conveniently and reliably.

Preferred embodiments of the invention will be explained by means of the

accompanying schematic drawings, in which

Figure 1 is a schematic view of a medical drill system with a drill, a control unit, an image generation device and a display device,

Figure 2 is a detail top view of a drilling head and a measuring probe of the drill shown in Figure 1,

Figure 3 is a detail side view of a drilling head and a measuring probe of the drill shown in Figure 1, and

Figure 4 is a detail view of a drilling tool of the drill shown in Figure 1.

Figure 1 shows a drill system 10 suitable for use in human medicine or veterinary medicine which comprises a drill 12 for forming drill channels in bones, teeth or other types of tissue. The drill 12 is provided with a drilling head 14, in which a drilling tool 16 can releasably be fixed. The drilling head 14 can be connected with different drilling tools 16, as required, so that drill channels of different sizes can be drilled into different tissue materials. The drill 12 further comprises a drive unit 18 which is configured to make the drilling tool 16 connected to the drilling head 14 rotate about a drilling axis A during operation of the drill 12.

The drill 12 of the medical drill system 10 is further equipped with a measuring probe 20. The measuring probe 20 has a transmitting unit 22, indicated schematically in Figures 2 and 3, and a receiving unit 24, likewise indicated schematically in Figures 2 and 3. In the embodiment of a measuring probe 20 shown in the figures, the measuring probe 20 is in the form of an ultrasonic probe, in particular in the form of a Doppler ultrasonic probe. The transmitting unit 22 is consequently an ultrasonic transmitting unit, while the receiving unit 24 is in the form of an ultrasonic receiving unit. Alternatively, however, it is also possible to use an optical coherence

tomography probe as the measuring probe 20. The transmitting unit 22 and the receiving unit 24 can then be in the form of a coherent light transmitting unit and a coherent light receiving unit, respectively.

As is shown in Figures 2 and 3, the measuring probe 20 is inserted into a first receiving channel 25a which is formed in the drilling head 14 and extends coaxially with the drilling axis A. In the embodiment of a medical drill system 10 shown in the figures, the measuring probe 20 is received in the first receiving channel 25a in a releasable and slidable manner, so that it can be removed from the first receiving channel 25a if required, for example for repair or cleaning purposes. The measuring probe 20 further projects into a second receiving channel 25b, see Figure 4, which is formed in the drilling tool 16 and likewise extends coaxially with the drilling axis 4. The measuring probe 20 is also received in the second receiving channel 25b in a releasable manner, so that it can be removed from the second receiving channel 25b for repair or cleaning purposes. Alternatively, the measuring probe 20 can also be integrated into the drilling tool 16 or be in the form of a drilling tool.

During a drilling operation, that is to say while the drilling tool 16, driven by the drive unit 18, is rotating about the drilling axis A and thereby producing a drill channel 26, the transmitting unit 22 transmits measuring signals, see Figure 4. In the case of a measuring probe 20 in the form of an ultrasonic probe, the transmitting unit 22 transmits ultrasonic signals. The measuring signals transmitted by the transmitting unit 22 of the measuring probe 20 are reflected differently by different types of tissue, such as, for example, bones, blood vessels or nerve pathways, in the vicinity of the drill channel 26. In particular, the measuring signals transmitted by the transmitting unit 22 of the measuring probe 20 are attenuated to different degrees by different types of tissue. The receiving unit 24 serves to receive the measuring signals transmitted by the transmitting unit 22, which during the drilling operation are reflected differently at tissue in the vicinity of the drill channel 26 according to the type of tissue.

The reflected measuring signals received by the receiving unit 24 are transmitted to a control unit 28 of the medical drill system 10, which control unit is configured to identify during the drilling operation different types of tissue in the vicinity of the drill channel 26 produced by means of the drilling tool 16 on the basis of the measuring signals transmitted by the transmitting unit 22 of the measuring probe 20 and also on the basis of the reflected measuring signals received by the receiving unit 24 of the measuring probe 20. In the embodiment of the medical drill system 10 shown by way of example in Figure 1, the control unit 28 is separate from the drill 12.

Alternatively, however, it is also conceivable to integrate the control unit 28 into the drill 12.

The control unit 28 comprises a memory 29 in which there are stored reference values for the reflection of the measuring signals transmitted by the transmitting unit 22 of the measuring probe 20 by different types of tissue. In the case of the drill 12 shown in the figures, which is equipped with a measuring probe 20 in the form of an ultrasonic probe, reference values for the attenuation of ultrasonic waves of a particular frequency by different types of tissue are stored in the memory 29 of the control unit 28. By comparing the reflected measuring signals transmitted thereto by the receiving unit 24 with the reference values stored in the memory 29, the control unit 28 is thus able to distinguish and identify different types of tissue, such as, for example, bones and nerve pathways, situated in the vicinity of the drill channel 26, during the drilling operation, that is to say without having to interrupt the drilling operation and remove the drilling tool 16 from the drill channel 26.

The control unit 28 is further connected to an image generation device 30. On the basis of the data transmitted thereto by the control unit 28, the image generation device 30 generates during the drilling operation, according to the form of the measuring probe 20, a two-dimensional or three-dimensional real-time image of the vicinity of the drill channel 26. The real-time image generated by the image generation device 30 is displayed on a display device 31. It is thereby possible to monitor the drilling operation and in particular the path of the drill channel in real time.

The transmitting unit 22 and the receiving unit 24 of the measuring probe 20 further transmit signals from which the control unit calculates a time lag between a measuring signal transmitted by the transmitting unit 22 of the measuring probe 20 and a measuring signal reflected at a sensitive tissue region 32 and received by the receiving unit of the measuring probe. The control unit 28 then determines from the time lag a distance D between the drill channel 26 and a sensitive tissue region 32. The sensitive tissue region 32 can be, for example, a nerve pathway which is not to be affected by the drill channel 26.

During the drilling operation, the transmitting unit 22 of the measuring probe 20 transmits first measuring signals in a direction substantially parallel to the drilling axis A and second measuring signals in a direction substantially perpendicular to the drilling axis A. Accordingly, the receiving unit 24 of the measuring probe 20 receives during the drilling operation the first and second measuring signals reflected at tissue in the vicinity of the drill channel 26. The vicinity of the drill channel 26 can thereby be monitored in the region of its side walls and of its tip. This allows the path of the drill channel to be guided particularly precisely, since both a distance Dl of the drill channel side walls from the sensitive tissue region 32 and a distance D2 of the drill channel tip from the sensitive tissue region 32 can be monitored during the drilling operation.

As is shown in Figure 4, the drilling tool 16 has in the region of its tip a first opening 33a for emission of the first measuring signals transmitted by the transmitting unit 22 of the measuring probe 20 and for delivery of the first measuring signals reflected at tissue in the vicinity of the drilling tool 16 to the receiving unit 24 of the measuring probe 20. The drilling tool 16 is further provided in the region of a side wall with a second opening 33b for emission of the second measuring signals transmitted by the transmitting unit 22 of the measuring probe 20 and for delivery of the second measuring signals reflected at tissue in the vicinity of the drilling tool 16 to the receiving unit 24 of the measuring probe 20.

The medical drill system 10 further comprises a warning signal output unit 36 arranged in the region of a handle 34 of the drill 12. The warning signal output unit 36, which, like further components of the drill 12, such as, for example, electric cables or signal cables, etc., can be embedded in the handle 34, is in the form of a traffic light system with a green, an amber and a red lamp 38, 40, 42. As long as the drill channel 26 is far enough away, for example 8 mm away, from the sensitive tissue region 32, the green lamp 38 of the warning signal output unit 36 is

illuminated. However, if the drill channel 26 comes closer, for example 6 mm, to the sensitive tissue region 32, the green lamp 38 is switched off and the amber lamp 40 of the warning signal output unit 36 is switched on. Finally, if during the drilling operation the distance D, calculated by the control unit 28, between the drill channel 26 and the sensitive tissue region 32 falls below a first threshold of, for example, 4 mm, the control unit 28 causes the warning signal output unit 36 to switch off the amber lamp 40 and to switch on the red lamp 42 and thus give out an optical warning signal. In addition or alternatively, the warning signal output unit 36 can also be configured to give out an acoustic warning signal if during the drilling operation the distance D, calculated by the control unit 28, between the drill channel 26 and the sensitive tissue region 32 falls below the first threshold.

The control unit 28 additionally controls the operation of the drive unit 18 of the drill 12. In particular, the control unit 28 interrupts the operation of the drive unit 18 and thus operation of the drill 12 if during the drilling operation the distance D, calculated by the control unit 28, between the drill channel 26 and the sensitive tissue region 32 falls below a second threshold. The second threshold is smaller than the first threshold and is, for example, 2 mm. By automatically switching off the drill 12 if the drill channel 26 comes too close to the sensitive tissue region 32, damage to the sensitive tissue region 32 is reliably avoided.

The first and the second threshold can be entered into an input unit 44 manually by a user. It is thereby possible, when controlling operation of the drill 12 by means of the control unit 28, to take account of patient-specific particularities, such as, for example, age-related reduced bone density or osteoporosis of the patient, which require a greater "safe distance" between the drill channel 26 and the sensitive tissue region 32.