US-12616418-B2 - Medical implants with circuits treating periprosthetic joint infection and other sensing

US12616418B2US 12616418 B2US12616418 B2US 12616418B2US-12616418-B2

Abstract

A medical implant includes an implant component configured to be implanted in a patient, an electrode array, an energy storage device, and a power management unit. The electrode array includes at least two electrodes spaced apart on the implant component. The energy storage device and power management unit are inside the implant component. The power management unit is operative to control electrical stimulation of the electrode array by current supplied by the energy storage device to be at a level which at least reduces formation of a biofilm on at least part of the implant component while implanted in the patient.

Inventors

Paden Troxell

Assignees

GLOBUS MEDICAL, INC.

Dates

Publication Date: 20260505
Application Date: 20230523

Claims (17)

1 . A medical implant comprising: an implant component configured to be implanted in a patient; an electrode array comprising at least two electrodes spaced apart on the implant component; an energy storage device inside the implant component; and a power management unit inside the implant component and operative to control electrical stimulation of the electrode array by current supplied by the energy storage device to be at a level which at least reduces formation of a biofilm on at least part of the implant component while implanted in the patient, a first set of the electrodes of the electrode array are spaced apart on a surface of the implant component; a second set of at least one of the electrodes, which is not among the first set of the electrodes, is spaced away from the first set of electrodes; and the power management unit is operative to control current density flowing from the first set of electrodes to the second set of the at least one of the electrodes through intervening tissue of the patent and/or to control current density flowing from the second set of the at least one of the electrodes to the first set of electrodes through intervening tissue of the patent.
2 . The medical implant of claim 1 , wherein the power management unit is operative to control current density through patient tissue between the at least two electrodes of the electrode array while the electrode array is electrically stimulated by the energy storage device, and further comprising a controller operative to control duration of the electrical stimulation of the electrode array by the power management unit.
3 . The medical implant of claim 2 , wherein: the power management unit is operative to control the current density to be a level sufficient to form hydrogen bubbles through reaction with the patient tissue and dislodge biofilm on a surface of the implant component.
4 . The medical implant of claim 2 , wherein: the power management unit is operative during a prevention modality to control the control current density to be in a range from 0.001 mA/mm{circumflex over ( )}2 to 0.01 mA/mm{circumflex over ( )}2; and the controller is operative during the prevention modality to control the duration of the electrical stimulation to be in a range from 8 hours to 24 hours.
5 . The medical implant of claim 2 , wherein: the power management unit is operative during an eradication modality to control the control current density to be in a range from 0.01 mA/mm{circumflex over ( )}2 to 0.1 mA/mm{circumflex over ( )}2; and the controller is operative during the eradication modality to control the duration of the electrical stimulation to be in a range from 1 minute to 8 hours.
6 . The medical implant of claim 2 , wherein: the power management unit is operative to control a current waveform supplied to at least one of the electrodes during at least a majority of the duration of the electrical stimulation, to be one of a constant directed current, a discontinuous pulsed direct current, and a discontinuous alternating direct current.
7 . The medical implant of claim 1 , wherein: the first set of the electrodes of the electrode array are spaced apart on a side surface of the implant component; and the second set of the at least one of the electrodes is on an upper surface of the implant component opposite to a lower surface of the implant component configured to be fixed to bone of the patient.
8 . The medical implant of claim 1 , wherein: the implant component comprises a tibial insert having a pair of tibial trays on an upper side adapted to guide rotational movement of a respective pair of femoral components of the medical implant, and having a tibial component on a lower side adapted to be cemented to a tibia of the patient; the first set of the electrodes of the electrode array are spaced apart on a side surface of the tibial insert; the second set of at least one of the electrodes comprises a centrally located electrode between the tibial trays; and the power management unit is operative to control current density through patient tissue between the first set of the electrodes and the centrally located electrode while electrically stimulated by the energy storage device.
9 . The medical implant of claim 1 , wherein: the implant component comprises a tibial insert having a pair of tibial trays on an upper side adapted to guide rotational movement of a respective pair of femoral components of the medical implant, and having a tibial component on a lower side adapted to be cemented to a tibia of the patient; the electrode array comprises a first electrode and a second electrode on one of the tibial trays, the first electrode at least partially encircling and electrically isolated from the second electrode, and a third electrode and a fourth electrode on the other one of the tibial trays, the third electrode at least partially encircling and electrically isolated from the fourth electrode; and the power management unit is operative to control current density through patient tissue between the first electrode and the second electrode while electrically stimulated by the energy storage device, and to control current density through patient tissue between the third electrode and the fourth electrode while electrically stimulated by the energy storage device.
10 . The medical implant of claim 9 , wherein: the first electrode has a continuous elongated shape at least partially encircling a majority of the second electrode; and the third electrode has a continuous elongated shape at least partially encircling a majority of the fourth electrode.
11 . The medical implant of claim 9 , wherein: the first electrode comprises a plurality of conductive segments electrically coupled and spaced apart along a path at least partially encircling a majority of the second electrode; and the third electrode comprises a plurality of conductive segments electrically coupled and spaced apart along a path at least partially encircling a majority of the fourth electrode.
12 . The medical implant of claim 1 , further comprising: a wireless communication transceiver; a pressure sensor operative to output a pressure signal indicative of pressure at a surface of the implant component and/or a force sensor operative to output a force signal indicative of force on a surface of the implant component; and a controller operative to record the pressures indicated by the pressure signal over time and/or to record the forces indicated by the force signal over time, and to communicate a report indicating the recorded pressures and/or the recorded forces through the wireless communication transceiver.
13 . The medical implant of claim 1 , further comprising: a wireless communication transceiver; an electrochemical sensor operative to output a signal indicative of a level of a defined chemical detected on the implant component; and a controller operative to record the levels of the defined chemical indicated by the signal over time, and to communicate a report indicating the levels of the defined chemical through the wireless communication transceiver.
14 . The medical implant of claim 1 , further comprising: a wireless communication transceiver; an inertial measurement unit operative to output inertial data indicative of acceleration of the implant component when moved by the patient; and a controller operative to record the inertial data over time, and to communicate a report indicating the recorded inertial data through the wireless communication transceiver.
15 . A medical implant comprising: an implant component configured to be implanted in a patient; an electrode array comprising at least two electrodes spaced apart on the implant component; an energy storage device inside the implant component; and a power management unit inside the implant component and operative to control electrical stimulation of the electrode array by current supplied by the energy storage device to be at a level which at least reduces formation of a biofilm on at least part of the implant component while implanted in the patient, a wireless communication transceiver; a microphone sensor operative to output a microphone signal indicative of sound generated by an articulating joint formed with the implant component when articulated by the patient; and a controller operative to record the sounds indicated by the microphone signal over time, and to communicate a report indicating the recorded sounds through the wireless communication transceiver.
16 . A medical implant comprising: an implant component configured to be implanted in a patient; an electrode array comprising at least two electrodes spaced apart on the implant component; an energy storage device inside the implant component; and a power management unit inside the implant component and operative to control electrical stimulation of the electrode array by current supplied by the energy storage device to be at a level which at least reduces formation of a biofilm on at least part of the implant component while implanted in the patient, a wireless communication transceiver; a temperature sensor operative to output a temperature signal indicative of temperature at a surface of the implant component; and a controller operative to communicate temperature data based on the temperature signal through the wireless communication transceiver, and to initiate electrical stimulation of the electrode array by the power management unit based on an activation command received through the wireless communication transceiver, the controller is further operative to initiate electrical stimulation of the electrode array by the power management unit based on a level of the temperature indicated by the temperature signal satisfying an eradication modality initiation rule.
17 . The medical implant of claim 16 , wherein: the controller is further operative to initiate electrical stimulation of the electrode array by the power management unit based on an observed trend over time in levels of the temperature indicated by the temperature signal satisfying an eradication modality initiation rule.

Description

FIELD The present disclosure relates to medical implants, such as for joint arthroplasty. BACKGROUND Periprosthetic joint infection (PJI) is one of the most feared complications in joint arthroplasty due to the ineffectiveness of antibiotics, invasive treatment options, and a relatively high annual mortality rate of 4%. If caught early enough, antibiotics and natural immune responses are very effective at intercepting the free-floating bacteria within the surgical site. However, antibiotics are remarkably ineffective at eradicating bacteria within biofilm on the surface of the implant. Biofilm develops as bacteria adhere to and colonize on the surface of an implant. The biofilm layer serves as a biochemical fortress that prevents penetration of antibiotic agents. It has been reported that 500-5000 times the concentration of antibiotics are required to have the same effectiveness on biofilm bacteria as compared to free-floating planktonic bacteria. As a result, the most common treatment for PJI is highly invasive two-stage revision. Two-stage revision involves an initial operation to remove the septic implant and debride the surgical site and a second procedure to place new implant components. Although two-stage revision is the most common treatment option for PJI, the success rate has been reported to be a mere 85%. In addition, the risk of reinfection following revision for PJI has been reported to be 9% compared to 1-2% following the primary procedure. Also, the annual mortality rate has been reported to be as high as 14% following two-stage revision. Much of the research and product development activity has been focused on preventing, rather than treating, infection following joint arthroplasty. Despite the incorporation of prevention strategies, including sterilization standards, shorter operative times, laminar airflow systems, body exhaust suits, perioperative antibiotics, antibiotic cement, and antimicrobial adhesive dressings, the incidence of PJI after THA and TKA has remained relatively constant over the past 20 years. This lack of improvement is likely due in part to the ineffectiveness of these solutions in preventing and eradicating the pathogenesis of joint infection, which is the formation of biofilm. SUMMARY Some embodiments of the present disclosure are directed to a medical implant that includes an implant component configured to be implanted in a patient, an electrode array, an energy storage device, and a power management unit. The electrode array includes at least two electrodes spaced apart on the implant component. The energy storage device and power management unit are inside the implant component. The power management unit is operative to control electrical stimulation of the electrode array by current supplied by the energy storage device to be at a level which at least reduces formation of a biofilm on at least part of the implant component while implanted in the patient. Some further embodiments are directed to the power management unit being operative to control current density through patient tissue between the at least two electrodes of the electrode array while the electrode array is electrically stimulated by the energy storage device. The medical implant can include a controller operative to control duration of the electrical stimulation of the electrode array by the power management unit. Some further embodiments are directed to arrangements of electrodes of the electrode array and to sensors providing data for reporting and which may result in the controller initiating therapeutic electrical stimulation of the electrode array. Some other embodiments are directed to a network computing resource that includes a network interface, processor, and memory storing instructions executable by the processor to perform operations. The operations include obtaining sensor data from at least one sensor of a medical implant within a patient, and providing to a display device indications of values of the sensor data. The operations communicate an activation command through the network interface addressed to a controller of the medical implant and are configured to initiate electrical stimulation by the controller of an electrode array at a level which at least reduces formation of a biofilm on at least part of an implant component while implanted in the patient. Other medical implants, network computing resources, and corresponding methods according to embodiments of the present disclosure will be or become apparent to one with skill in the art upon review of the following drawings and detailed description. It is intended that all such additional medical implants, network computing resources, and methods be included within this description, be within the scope of the present inventive subject matter, and be protected by the accompanying claims. Moreover, it is intended that all embodiments disclosed herein can be implemented separately or combined in any way and/or combination. DESCRIPTI