Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B90/00—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
  • A61B90/10—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges for stereotaxic surgery, e.g. frame-based stereotaxis
  • A61B90/14—Fixators for body parts, e.g. skull clamps; Constructional details of fixators, e.g. pins
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B90/00—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
  • A61B90/10—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges for stereotaxic surgery, e.g. frame-based stereotaxis
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B90/00—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
  • A61B90/10—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges for stereotaxic surgery, e.g. frame-based stereotaxis
  • A61B2090/101—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges for stereotaxic surgery, e.g. frame-based stereotaxis for stereotaxic radiosurgery

Definitions

• HFDs head stabilization devices which are also referred to as head fixation devices
• HFDs head stabilization devices
• HFDs head fixation devices
• FIG. 1 depicts a perspective view of an exemplary HFD.
• FIG. 2 depicts a partial front view of a pin holder assembly of the HFD of FIG. 1, with the pin holder assembly configured to hold a single pin.
• FIG. 3 depicts a partial front view of another pin holder assembly of the HFD of FIG. 1, with the pin holder assembly configured to hold a pair of pins.
• FIG. 4 depicts an enlarged cross section view of a portion of the pin holder assembly of FIG. 2.
• FIG. 5 depicts an enlarged cross section view of a portion of the pin holder assembly of FIG. 3.
• FIG. 6 depicts an exemplary HFD including an overlay of an exemplary force distribution.
• FIG. 7 depicts an imaging output showing pin penetration into a skull on the single pin side of an HFD.
• FIG. 8 depicts an imaging output showing pin penetration into a skull on the 2-pin side of an HFD.
• FIG. 9 depicts another exemplary pin usable with the HFD of FIG. 1.
• FIG. 10 depicts another exemplary pin usable with the HFD of FIG. 1.
• FIG. 1 illustrates an exemplary HFD in the form of a skull clamp (10). While the present example illustrates the HFD as a U-shaped skull clamp, the teachings herein may be applied to other forms of HFDs as will be understood by those of ordinary skill in the art in view of the teachings herein.
• Skull clamp (10) comprises a first arm (12) and a second arm (14).
• First arm (12) is connectable with second arm (14) to form skull clamp (10) having a U-shape.
• First arm (12) comprises an upright portion (16) and a lateral portion (18).
• second arm (14) comprises an upright portion (20) and a lateral portion (22).
• Skull clamp (10) is adjustable to accommodate a variety of head sizes by translating first arm (12) relative to second arm (14) or vice versa. Skull clamp (10) is further connectable to other structures, such as a positioning adapter or a base unit that is further connectable with an operating table, etc., by way of an attachment interface (24). As shown in the present example of FIG. 1, upright portion (16) of first arm (12) connects with a pin assembly (100), while upright portion (20) of second arm (14) connects with a pin assembly (200).
• pin assembly (100) comprises a torque screw (102) configured to adjust an amount of clamping force skull clamp (10) applies to the head of the patient.
• Torque screw (102) comprises a wheel (104), a sleeve (106), a spring (not shown), and an elongated member (110).
• Sleeve (106) has a threaded outer surface that threadably engages with a threaded bore in upright portion (16) of arm (12).
• Sleeve (106) has an interior space where the spring is located. At a proximal end, the spring contacts wheel (104). At a distal end, the spring contacts a flange of elongated member (110).
• Wheel (104) is connected with sleeve (106) such that rotation of wheel (104) causes a corresponding rotation of sleeve (106). With this configuration, as wheel (104) is rotated, wheel (104) and sleeve (106) translate relative to upright portion (16) based on the threaded engagement depending on the direction of rotation of wheel (104).
• Elongated member (110) extends through a bore in wheel (104) and elongated member (110) is secured to a screw (112) at its proximal end. At its distal end, elongated member (110) retains a pin holder (114) that retains a pin (116). In use, at least a distal tip (118) of pin (116) contacts the head of the patient.
• pin assembly (200) connects with upright portion (20) of arm (14) as shown.
• this connection between pin assembly (200) and upright portion (20) is such that the lateral position of pin assembly (200) relative to upright portion (20) of arm (14), is fixed once the pivot position is set as discussed below.
• Pin assembly (200) comprises rocker arm (202), which retains pin holders (204), which in turn retain pins (206) configured to contact the head of the patient.
• Rocker arm (202) is rotatably adjustable about an axis Bl extending through a bore in upright portion (20). This rotation can be selectively controlled such that the rotatable position of rocker arm (202) can be locked in position or unlocked for adjustment.
• pin assembly (200) is also configured such that rocker arm (202) is pivotably adjustable about an axis B4 defined longitudinally by pin (214). Regardless of the rotational or pivotal adjustments, the force applied to the head of the patient via torque screw (102) of pin assembly (100) as described above, causes force to also be applied to the head of the patient from pin assembly (200) and its pins (206) that are configured to contact the head of the patient.
• the head of a patient can be stabilized.
• the force applied by pin assembly (100) can be between about 270 newtons and about 360 newtons.
• the precise amount of force used should be gauged according to a given surgeon’s needs taking into consideration such things as the procedure type, the patient’s bone structure and condition, etc.
• the precise amount of force used may be an amount such that pin (116) and pins (206) anchor in the bone of the skull, but without penetrating the entire way through the bone.
• the example force range provided above, as well as anywhere else, is merely exemplary and should not be interpreted as limits or limiting in any fashion. Accordingly, it should be understood that in some other examples the stabilization force used can be greater or less than the range presented above of between about 270 newtons and 360 newtons.
• torque screw (102) is configured in some versions with a gage or scale that indicates the total force applied, which denoted F to .
• F to the total force applied
• this force is applied to both sides by pin assemblies (100, 200) as shown as F ⁇ for the force applied by pin assembly (100), and F 2 for the force applied by pin assembly (200).
• F t and F 2 would each be 360 newtons. In this manner equal and opposite forces would be applied to the sides of the head of the patient.
• the force distribution differs because the force applied by pair of pins (206) is divided between each pin (206) of the pair. Accordingly, in a simplified example the 360 newtons of force for F 2 is divided equally between each pin (206) of the pair, such that each pin (206) applies 180 newtons of force when single pin (116) applies 360 newtons of force as indicated on the scale or gage of torque screw (102). In this example, the force applied on each side of the head of the patient is equal at 360 newtons.
• the force applied to the head of the patient is an important variable in terms of the ultimate pressure applied at the head of the patient where the pins contact the head. Pressure is directly related to the applied force by the relationship that pressure P equals force F divided by area A as shown in Equation 1.
• the pressure at the side with pin assembly (100) would be calculated as the force divided by the area.
• the area on the side with pin assembly (100), area Ai is equal to the contact area provided by pin (116) with the head of the patient.
• the pressure at the side with pin assembly (200) could be calculated similarly as the force F 2 divided by the area.
• the force F 2 is split between the two pins (206) as mentioned above.
• each pin (206) has an associated area A 2 . So, the pressure on the 2-pin side where each pin (206) contacts the head of the patient equals half of the force F z divided by the contact area A 2 provided by pin (206).
• FIGS. 1-5 uses pins having differing configurations to achieve uniform or more uniform pressure at each location where one of pins (116, 206) contacts the patient’s head for stabilization.
• skull clamp (10) such that in use, each pin (206) of pin assembly (200) generates a pressure that equals the pressure generated by single pin (116) of pin assembly (100).
• this is achieved by using pins having different pin angles thereby altering the contact areas to influence the pressure according to the equations above.
• Equation 2 can be simplified to Equation 3 below, which is the same equation for calculating the pressure at pin (116).
• the pressure at pins (206) is increased to match the pressure at pin (116) on the single pin side.
• This uniform pressure profile or distribution provides for uniform bone penetration at each location where pins (116, 206) contact the head of the patient, which in turn promotes a more rigid and secure stabilization.
• This also provides the ability to avoid excessive pressure use on the single pin side when trying to achieve acceptable bone penetration on the 2-pin side, thereby reducing trauma to the patient.
• the uniform pressure distribution mentioned above is achieved by maintaining the same force applied to each side of the head of the patient.
• pin (116) is shown in cross section, and defines a longitudinal axis LA1 extending through pin (116). Furthermore, pin (116) comprises a body portion (120) and a tapered portion (122). Pin (116) further defines an axis B2, which extends from distal tip (118) proximally along pin (116). The intersection of longitudinal axis LA1 and axis B2 define a pin angle ocl.
• pin (206) is shown in cross section, and defines a longitudinal axis LA2 extending through pin (206). Furthermore, pin (206) comprises a body portion (208) and a tapered portion (210). Pin (206) further defines an axis B3, which extends from a distal tip (212) proximally along pin (206). The intersection of longitudinal axis LA2 and axis B3 define a pin angle oc2.
• pin (116) has a pin angle of ocl
• pins (206) each have a pin angle of oc2, and pin angle ocl does not equal pin angle oc2.
• pins (206) have a pin angle oc2 that is smaller than the pin angle ocl of pin (116).
• the first pin angle and the second pin angle are each within the range of about 3 degrees to about 45 degrees. In some other versions this range can be about 3 degrees to about 23 degrees.
• the pin angle oc2 of pins (206) on the 2-pin side is greater than or equal to about 1 degree smaller than the pin angle ocl of pin (116) on the single pin side.
• the difference in pin angle ocl, oc2 of pins (206) and pin (116) can be larger or smaller than 1 degree.
• the about 1 degree difference stated in the above example is non limiting and merely one example of a difference in pin angle ocl, oc2 of pins (206) and pin (116).
• the pin angle oc2 of pins (206) on the 2-pin side is greater than or equal to about 5 degrees smaller than the pin angle ocl of pin (116) on the single pin side.
• the difference in pin angle ocl, oc2 of pins (206) and pin (116) is such that the pin angle oc2 of pins (206) is about half of the pin angle al of pin (116).
• the pin angle al of pin (116) and the pin angle a2 of pins (206) are each within the range of about 3 degrees to about 45 degrees with the difference between the pin angle al and the pin angle a2 is at least about 1 degree.
• the pin angle al of pin (116) and the pin angle a2 of pins (206) are each within the range of about 3 degrees to about 23 degrees with the difference between the pin angle al and the pin angle a2 is at least about 1 degree. Still yet, in another version of skull clamp (10), the pin angle a2 of pins (206) on the 2-pin side is between about 1 degree and about 5 degrees smaller than the pin angle al of pin (116) on the single pin side.
• the contact area for pin (206) is less and therefore the force applied to and through pins (206) is applied over a smaller contact area which in turn increases the pressure.
• Another way area or contact area can be assessed is by considering the circular area of the pin in cross section at a given penetration depth relative to the skull bone.
• this circular area of pins (206) on the 2-pin side is less than or smaller than this circular area of pin (116) on the single pin side.
• this circular area of pins (206) on the 2-pin side is less than or equal to 0.6 times smaller than this circular area of pin (116) on the single pin side.
• the magnitude of the difference in cross sectional circular areas of pins (206) compared with pin (116) can be greater or less than the example above having 0.6 times smaller circular area.
• this circular area of pins (206) on the 2-pin side is about half of this circular area of pin (116) on the single pin side.
• pins (206) on the 2-pin side are different in shape compared with pin (116) on the single pin side; thus the pins (116, 206) are not uniform in this respect.
• other ways to characterize pins (116, 206), pin angles, contact areas, etc. will be apparent to those of ordinary skill in the art. Accordingly, the examples above should be considered non-exhaustive and non-limiting.
• pins (316, 416) are shown that can be used in place of any of the pins of skull clamp (10) and pin assemblies (100, 200).
• pin (316) or pin (416) is used instead of pin (116).
• pins (316, 416) illustrate examples having larger pin angles (oc3, oc4). In the present examples of FIGS. 9 and 10, pin angles (oc3, oc4) are about 45 degrees; however, in other versions pin angles can be more or less than about 45 degrees.
• Pin angles (oc3, oc4) are defined in the same manner as described above with respect to pin angles (ocl, oc2). More specifically, pin (316) is shown in cross section in FIG. 9, and defines a longitudinal axis LA3 extending through pin (316). Furthermore, pin (316) comprises a body portion (320) and a tapered portion (322). Pin (316) further defines an axis B5, which extends from distal tip (318) proximally along pin (316). The intersection of longitudinal axis LA3 and axis B5 define a pin angle oc3.
• pin (416) is shown in cross section in FIG. 10, and defines a longitudinal axis LA4 extending through pin (416). Furthermore, pin (416) comprises a body portion (420) and a tapered portion (422). Pin (416) further defines an axis B6, which extends from distal tip (418) proximally along pin (416). The intersection of longitudinal axis LA4 and axis B6 define a pin angle oc4.
• skull clamp (10) is configured such that in use, the pin (316, 416) of pin assembly (100) generates a pressure that equals the pressure generated by each pin (206) of pin assembly (200). For instance, one way to match pressures is to decrease the pin angle on the 2-pin side, while another way to match pressures is to increase the pin angle on the single pin side.
• pins (316, 416) in place of pin (116) takes this latter approach, whereas using pins (206) on the 2-pin side instead of using all pins configured like pin (116) takes the former approach to matching pressures. Still yet, in view of the teachings herein, those of ordinary skill in the art will appreciate other ways to modify the pins on one or both sides of the patient’s head to achieve a uniform or more uniform pressure application.
• pin (416) has a geometry with a larger conical shaped portion compared to pin (316). In terms of the contact area calculation from Equation 4 above, this translates to pin (416) having a larger radius of the cone portion and a larger height of the cone portion. This means that pin (416) can provide for greater contact surface area as pins (316, 416) penetrate the skull bone. In this manner the force applied when using pin (416) can be distributed over a larger area and thus provide a lower pressure.
• a device for stabilizing a head of a patient during a medical procedure comprising: (a) a first pin assembly having a first pin configured to engage a skull of the patient to stabilize the head of the patient, wherein the first pin comprises a first pin angle; and (b) a second pin assembly having a pair of pins configured to engage the skull of the patient to stabilize the head of the patient, wherein each pin of the pair of pins comprises a second pin angle different than the first pin angle of the first pin.
• Example 1 The device of Example 1, wherein the first pin assembly and the second pin assembly are configured to be positioned on opposite sides of the head of the patient.
• a longitudinal cross section of the first pin defines the first pin angle by an intersection of a longitudinal axis of the single pin with an axis of the single pin extending from a distal tip of the single pin proximally along the single pin; and wherein a longitudinal cross section of each pin of the pair of pins defines the second pin angle by an intersection of a longitudinal axis of each respective pin of the pair of pins with an axis of each respective pin of the pair of pins extending from a distal tip of each respective pin of the pair of pins proximally along each respective pin of the pair of pins.
• Example 5 The device of any one or more of Examples 1 through 4, wherein the first pin angle and the second pin angle are configured such that a pressure exerted on the head of the patient when stabilized is substantially equal where the first pin and the pair of pins each contact the head of the patient.
• the device comprises a skull clamp having a first arm and a second arm that are selectively and adjustably connectable, wherein the first arm comprises a first upright portion connected with a first lateral portion, wherein the second arm comprises a second upright portion connected with a second lateral portion, wherein the first pin assembly connects with the first upright portion, and wherein the second pin assembly connects with the second upright portion.
• Example 10 The device of any one or more of Examples 1 through 9, wherein the first pin assembly comprises a force adjustment feature configured to adjust an amount of force applied by the first pin to the head of the patient, wherein the amount of force applied by the first pin when stabilizing the head of the patient is between about 270 newtons and about 360 newtons.
• a device for stabilizing a head of a patient during a medical procedure comprising two or more pin assemblies, wherein each of the pin assemblies comprises at least one pin configured to engage a skull of the patient to stabilize the head of the patient, wherein the at least one pin of a select one of the two or more pin assemblies comprises a first pin angle, and wherein the at least one pin of another select one of the two or more pin assemblies comprises a second pin angle, wherein the first pin angle and the second pin angle differ.
• a device for stabilizing a head of a patient during a medical procedure comprising (a) a first pin assembly having a single pin configured to engage a skull of the patient to stabilize the head of the patient; and (b) a second pin assembly having a pair of pins configured to engage the skull of the patient to stabilize the head of the patient, wherein the pair of pins and the single pin are non-uniform.
• Example 15 The device of Example 15, wherein the pair of pins are different in shape compared with single pin.
• a device for stabilizing a head of a patient during a medical procedure comprising (a) a first pin assembly having a single pin configured to engage a skull of the patient to stabilize the head of the patient, wherein the first pin comprises a first tapered portion having a first conical shape with a first radius; and (b) a second pin assembly having a pair of pins configured to engage the skull of the patient to stabilize the head of the patient, wherein the pair of pins each comprise a second tapered portion having a second conical shape with a second radius, wherein the second radius is smaller than the first radius.

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• 2019
  • 2019-09-25 JP JP2021516661A patent/JP2022502145A/ja active Pending
  • 2019-09-25 EP EP19809603.4A patent/EP3856067B1/en active Active
  • 2019-09-25 CN CN201980062867.0A patent/CN112770692B/zh active Active
  • 2019-09-25 US US16/582,167 patent/US12090000B2/en active Active
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• 2024
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