Abstract: A method for determining a variable which represents the condition of a driver of a vehicle, the variable being determined independently of the time using at least one other variable representing the light intensity to which the driver is exposed.

Abstract: A sensor for contactless electrocardiographic measurement on a person includes a carrier for mounting to a seat, an electrode for registering a measurement signal, a pressure sensor supporting the electrode on the carrier, and moisture and temperature sensors mounted to the carrier to detect conditions adjacent to the electrode and the subject person. The moisture sensor and the temperature sensor may be adjacent to at least one opening in the electrode. A processing unit receives information generated by the pressure sensor, the moisture sensor, and the temperature sensor, and filters the measurement signal based on the information. An acceleration sensor may also be mounted to the carrier and/or electrode and send signals to the processor.

Abstract: A method for controlling gait-training apparatus using biofeedback is provided. A biosignal-detecting loop is used to detect and analyze the electromyographic signal of a user using the gait-training apparatus. A feedback control loop is used to drive the gait-training apparatus and determine the fatigue level of the user. When the user's muscle starts to become fatigue, the feedback control loop can further adjust the threshold for triggering the gait-training apparatus to retain the training session so that the training intensity can be regulated on-line and the user's muscle can be trained effectively based on the concept of progressive overload.

Abstract: Provided are devices and methods suitable for immobilizing tissue and for use in non-invasive methods of assessing lower urinary tract symptoms as well as in surgical application.

Abstract: Cardiac monitoring and/or stimulation methods and systems employing dyspnea measurement. An implantable cardiac device may sense transthoracic impedance and determine a patient activity level. An index indicative of pulmonary function is implantably computed to detect an episode of dyspnea based on a change, trend, and/or value exceeding a threshold at a determined patient activity level. Trending one or more pulmonary function index values may be done to determine a patient's pulmonary function index profile, which may be used to adapt a cardiac therapy. A physician may be automatically alerted in response to a pulmonary function index value and/or a trend of the patient's pulmonary index being beyond a threshold. Computed pulmonary function index values and their associated patient's activity levels may be stored periodically in a memory and/or transmitted to a patient-external device.

Abstract: An implantable medical device has an impedance processor that determines impedance data reflective of the transvalvular impedance of a heart valve of a heart during a heart cycle. The determined impedance data are processed by a representation processor that estimates diastolic and systolic transvalvular impedance representations. A condition processor determines the presence of any heart valve malfunction, such as valve regurgitation and/or stenosis, of the heart valve based on the estimated diastolic and systolic transvalvular impedance representations.

Abstract: A non-resistive contact sensor assembly includes an electric field sensor device, including a dielectric component for receiving an electrical signal from an object of interest and a signal processing component for processing the electrical signal, a voltage regulator for controlling voltage to the dielectric component and the signal processing component, and a common ground reference for the dielectric component and the signal processing component.

Abstract: Present embodiments are directed to a system and method capable of modulating light to at least one modulation frequency selected based on at least one blood parameter of a medium being monitored to generate photon density waves in a medium, detecting relative amplitude changes and phase shifts in the photon density waves, and determining at least one blood parameter related to scattering particles in the medium based on the phase shifts.

Abstract: Disclosed herein is a framework for facilitating patient signal analysis. In accordance with one aspect, actiniform segmentation is performed on patient signal data waveform based on an actiniform shape. The actiniform shape is centered at a peak of the waveform and includes connection lines extending from the peak to key time points of the patient signal data waveform. Actiniform parameters may be extracted from the segmented patient signal data waveform. Additionally, one or more actiniform ratios may be determined based on the actiniform parameters to monitor changes in the patient signal data waveform.

Abstract: A system for simulating various clinical conditions which are detectable by a noninvasive respiratory monitor is provided. The simulated clinical conditions may be displayed on a noninvasive respiratory monitor to replicate a variety of disease states to provide training for a clinician. The system may include a pulse oximetry simulation device and/or a CO2 delivery system.

Abstract: An image diagnosis assistance apparatus calculates a first characteristic value based on an image feature of an image that is a diagnosis target, acquires a second characteristic value based on the findings information of the image input by a user via an operation unit, and performs diagnostic inference for a predetermined region of the image based on the first characteristic value, the second characteristic value, and the reliability of inference of the first characteristic value and the second characteristic value.

Abstract: Methods and apparatuses monitor and evaluate the movement and sounds of an individual in a sleeping structure to identify individual movement and sound activities that are outside acceptable movement and sound tolerances. Similarly, the methods and apparatuses monitor and evaluate the gases surrounding the individual and the temperature and humidity to identify environmental conditions that are outside acceptable environmental tolerances. The methods and apparatuses constantly and dynamically change the acceptable movement and sound tolerances and the acceptable environmental tolerances based on the age of the individual and based on historical monitoring of the movement and sounds of the individual, historical monitoring of the gases surrounding the individual, and historical monitoring of the temperature and humidity surrounding the individual.

Abstract: In one embodiment, an X-ray computed tomography apparatus includes an X-ray tube, an X-ray detector, a rotating mechanism, a high voltage generating unit, a reconstruction processing unit, a projection image generating unit configured to generate a projection image based on output from the X-ray detector, an image display unit, and a fluoroscopy control unit configured to control the rotating mechanism, the high voltage generating unit, the X-ray detector, the projection image generating unit and the image display unit to implement stereo fluoroscopy.

Abstract: A method of imaging a patient and an X-ray dosimetry system are provided. The X-ray dosimetry system includes a support platform configured to support an object to be imaged and a digital X-ray dosimeter mounted on a surface of the support platform, the X-ray dosimeter configured to receive incident radiation prior to the incident radiation having passed through the object to be imaged, the X-ray dosimeter comprising a thickness of less than about four millimeters.

Abstract: An X-ray CT apparatus for obtaining an internal image of a test subject by using X-rays. The X-ray CT apparatus has: an X-ray generator; an X-ray detector; a first casing for enclosing the X-ray generator and the X-ray detector; a test-subject table; a first table transporting mechanism for transporting the test-subject table between a first table position and a second table position, the first table position being a position where the main portion of the test-subject table receives X-rays from the X-ray generator, and the second table position being a position where the main portion of the test-subject table is on the outside of the first casing; and a second table transporting mechanism capable of vertically transporting the test-subject table. The first table transporting mechanism and the second table transporting mechanism operate in association with each other.

Abstract: A radiation detection apparatus includes conversion elements including a first electrode, a semiconductor layer, and a second electrode that are divided for each pixel; switching elements electrically connected to the first electrodes; and a first insulating layer that separates the conversion elements of adjacent pixels. The semiconductor layer is located between the first and second electrodes. A periphery of the semiconductor layer is located outside peripheries of the first and second electrodes. The semiconductor layer includes a first impurity semiconductor layer, a second impurity semiconductor layer, and an intrinsic semiconductor layer located between the first and second impurity semiconductor layers. Parameters of the apparatus are defined to set a residual charge 10 ?s after the switching element is turned on to be not higher than 2%.

Abstract: An X-ray examination station includes a first source of X-ray radiation for whole body scanning of a human body using a first fan beam of X-ray radiation; a first vertical linear radiation detector configured to detect the first fan beam; a second source of X-ray radiation installed at mid-height of a person being examined, for scanning a central portion of the human body using a second fan beam of X-ray radiation; a second vertical detector of X-ray radiation configured to detect the second fan beam; and a control unit configured to turn on each of the X-ray radiation sources. The first and the second radiation fan beams are emitted in parallel planes. The first X-ray radiation source is turned on for the whole body scanning. The second X-ray radiation source is turned on for scanning the central portion of the body.

Abstract: A PET-MR apparatus includes an MR imaging system for acquiring MR signals and a PET system for acquiring PET emissions of the patient. The PET-MR apparatus also includes an anterior surface coil configured to receive MR signals from a volume-of-interest of the patient in the bore and resulting from the emitted RF pulse sequence and a coil positioning structure mounted to the PET-MR apparatus and configured to receive the anterior surface coil thereon and position the anterior surface coil proximate to the volume-of-interest of the patient without coming in contact with the patient, with the coil positioning structure being configured to provide both a vertical adjustment of the anterior surface coil relative to a coronal plane of the patient and an angular adjustment of the anterior surface coil relative to the coronal plane of the patient.

Abstract: An apparatus for cone beam computed tomography of an extremity has a digital radiation detector and a first device to move the detector along a circular detector path extending so that the detector moves both at least partially around a first extremity of the patient and between the first extremity and a second, adjacent extremity. The detector path has radius R1 sufficient to position the extremity approximately centered in the detector path. There is a radiation source with a second device to move the source along a concentric circular source path having a radius R2 greater than radius R1, radius R2 sufficiently long to allow adequate radiation exposure of the first extremity for an image capture by the detector. A first circumferential gap in the source path allows the second extremity to be positioned in the first circumferential gap during image capture.

Abstract: An X-ray imaging apparatus having an improved structure to reduce noise generated when a position of an X-ray generator is fixed in position includes an X-ray generator, an X-ray detector, a moving carriage coupled with one end of the X-ray generator, a guide rail, and a holding unit disposed at an inner side of the moving carriage to hold the position of the X-ray generator, wherein the holding unit includes a contact pad to contact the guide rail to hold the moving carriage, a magnetic body to move the contact pad using magnetic force, and a holding plate coupled to the contact pad to move according to operation of the magnetic body and including a buffer material capable of absorbing noise or vibration.

Abstract: Systems and methods of optimal pulse compression are described. A method of determining an optimal pulse takes as an input a function of the impulse response of a transducer and produces a pulse optimized for transmission through that transducer. Images then produced with that transducer will have both superior range and spatial resolution.

Abstract: A method is provided for detecting lesions in ultrasound images. The method includes acquiring an ultrasound image, generating a Fisher-tippett (FT) distribution-based edge feature map from the acquired ultrasound image, generating gradient concentration (GC) scores for pixels of the acquired ultrasound image using the FT distribution-based edge feature map, and identifying a candidate lesion region within the acquired ultrasound image based on the GC scores.

Abstract: A system for sealing a hole in a body, comprising a generally cylindrical mesh formed from a plurality of helical strands which is inserted into the hole, with at least one end of the cylindrical mesh being moved least partially through an interior portion of the cylindrical shaped mesh such that the mesh expands radially outwards against sides of the hole.

Abstract: Among other things, there are disclosed apparatuses and methods for medically sealing an opening in a vessel or wall. For example, in medical applications, a delivery tube is provided for insertion through a sheath into a vessel (e.g. a blood vessel). A dome-shaped seal fixed to a filament, an absorbent and/or compressible buffer, and a locking member are provided in the delivery tube. The delivery tube is configured so that it can be inserted into the vessel through a sheath. Tension is maintained on the filament to hold the seal against the tube or sheath. The sheath is pulled out, which pulls out the tube at the same time, leaving the seal over the opening in the vessel wall. The locking member compresses the buffer against the outside of the vessel and with the filament holds the seal in place against the inside of a vessel.

Abstract: A medical device includes a balloon member, a port that couples a compartment interior of the balloon member to a region exterior of the balloon member, and a tubular member that defines a lumen. A distal end of the tubular member is attached to an internal surface of the balloon member within the compartment so that a portion of the internal surface of the balloon member provides a seal at a distal end of the lumen. The tubular member passes through the port, and the proximal end of the tubular member is configured to remain exterior of the compartment. A delivery of a sufficient amount of a filling material into the lumen of the tubular member causes a length of the tubular member to pass through the port and into the balloon compartment.

Abstract: A quick-release handle is used in positioning a retractor blade in a surgical site and securing the retractor blade to a retractor frame. The retractor blade has a generally cylindrical post for removably engaging a retractor frame, an alignment groove on its top surface, and an annular recess extending around the post. The quick-release handle has a head with a U-shaped flange for sliding engagement with the annular recess and the upper portion of the post. The handle also contains a sliding rod actuated by a thumb-slide mechanism to engage the alignment groove on the retractor blade post. In particular, a locking tongue extending from the distal end of the rod engages the alignment groove, while a protrusion extending from the rod engages the annular recess, thereby maintaining proper rotational alignment between the handle and retractor blade.

Abstract: An access assembly for insertion through an opening in tissue is provided. The access assembly includes a flexible outer sleeve having an upper rim formed on a proximal end, a lower rim formed on a distal end and defining a longitudinal opening extending therebetween. The lower rim may define an inflatable space that in a deflated state facilitates insertion of the lower rim through tissue and in an inflated state assists in retaining the access assembly in place relative to the tissue. The access assembly further includes an inflatable member secured within the longitudinal opening of the outer sleeve. The inflatable member includes a plurality of inflatable lobes configured to selectively receive at least one surgical device therebetween in a sealing manner.

Abstract: A retractor (101) for retracting the margins of a wound opening (103) comprises an inner anchoring O-ring (105) attached to a cylindrical sleeve (106) at a distal end and a reinforcing O-ring (109) attached to a proximal end of the sleeve (106). The sleeve (106) is led between an inner ring part (110) and a corresponding recess (116) in an outer ring part (111). The outer ring part (111) has anchor formations (120) over which the proximal end of the sleeve (106) is attached to anchor the sleeve (106). To retract the wound opening (103) the sleeve (106) is pulled while the guide rings (110, 111) are moved against the tissue surrounding the wound opening (103). This pulls the inner O-ring (105) against the inside of the tissue adjacent the wound opening (103), and retracts the wound opening (103). The sleeve (106) is manipulated locally for maximum retraction efficiency.

Abstract: An anchor device and system for coupling soft tissue to osseous tissue includes a stopper member that supports a loop of suture material. A fixing member includes features that allow it to be rigidly coupled to surrounding bone and thus hold the stopper member in a cavity within the bone. The loop of suture material, in turn, supports a second suture device, which is coupled to, and thus retains, the soft tissue. In certain embodiments, the stopper member includes a mechanical linkage for coupling it to the fixing member, and surface features that resist withdrawal of the fixing member from the bone.

Abstract: A method for securing suture to bone comprises drilling a hole in a desired portion of bone at a desired procedural site, passing a strand of suture through a portion of soft tissue to be approximated to the portion of bone, and extending the free suture ends proximally from the soft tissue. The suture is loaded into an anchor implant. Using an inserter, on a distal end of which is attached the anchor implant, the anchor implant is manipulated into the bone hole. The suture is then tensioned to a desired level by pulling on the free suture ends, after the anchor implant is positioned in the bone hole. The free suture ends are wrapped about a suture cleat on an inserter handle once the desired tension level is achieved. A proximal anchor component is moved distally to engage with a distal anchor component to lock the anchor in place within the bone hole, and to lock the suture in place within the anchor. Then, the inserter is removed from the procedural site.

Abstract: Methods and devices for fixation of soft tissue to bone are provided. In one embodiment, a suture anchor is provided having an elongate cylindrical body with proximal and distal ends and an inner lumen extending therethrough. The elongate body can be configured so that upon partial insertion into a bone hole, it is securely anchored within the bone hole and a suture extending through the inner lumen is freely slidable. It can also configured so that, upon further insertion into the bone hole, at least a portion of the elongate body compresses to lock the suture within the inner lumen such that the suture is prevented from sliding. In another embodiment, a suture anchor is provided having arms that have an open position for receiving a suture therebetween, and a closed position in which the suture is retained but allowed to slide freely.

Abstract: In one embodiment, a fixation system includes an anchor adapted to be implanted within a first bone, a washer adapted to be associated with a second bone that is to be secured to the first bone, and a suture that is fixedly attached at one end to the anchor and that extends between the anchor and the washer in multiple passes, the suture being adapted to extend through a passage formed in the first and second bones.

Abstract: Provided herein are devices and methods for anterior arytenoid adduction. The device may comprise a wire having a first end and a second end at opposite ends of a longitudinal axis, the wire forming a spiral along the longitudinal axis and having a double hook at the first end, a suture threaded through the spiral of the wire from the second end to the first end, the suture forming a turn at the first end and passing exterior to the spiral to the second end. The method may comprise advancing a suture and hook from the subject's anterior thyroid cartilage or cricothyroid membrane to the muscular process of the subject's arytenoid, attaching the hook to the muscular process, and applying tension to the suture to rotate the muscular process and adduct the arytenoid.

Abstract: A device for deploying a tissue fixation apparatus of the type including first and second tissue anchors coupled together by an adjustable suture assembly. The device comprises a handle mechanism and a needle cartridge assembly releasably coupled to the handle mechanism. The needle cartridge assembly includes a needle cannula with a side opening through which a tissue anchor can be loaded into an internal chamber of the needle cannula. A push rod is disposed in the needle cannula and is operable between an extended position in which the push rod prevents the tissue anchor from entering the chamber through the side opening, and a retracted configuration in which the tissue anchor can be pushed into the chamber under the action of a resilient band positioned over the side opening.

Abstract: Methods and apparatus for providing transapical access to a heart chamber for performing an intra cardiac procedure are described. The apparatus include a helical needle driver, a dilator, a straight access needle, and optionally a guidewire. After entering the heart chamber with the straight access needle, the helical needle driver is used to place a helical suture within the myocardium. After removing the needle driver, the dilator is advanced through the pre-placed helical suture, dilating both a passage and the circumscribing suture. After performing procedure, the pre-placed suture may be closed by proximally retracting an external end of the suture.

Abstract: A suture needle driving instrument comprises a shaft, an end effector, and a handle assembly. The end effector is located at the distal end of the shaft and includes a pair of grasping arms operable to grasp and release a needle. The handle assembly comprises a trigger-operated actuation assembly that is operable to rotate a second grasping arm relative to the shaft. The trigger-operated actuation assembly may include a trigger and a trigger gear assembly that is operable to rotate the second grasping arm. A clutch assembly may also be included to selectively couple a drive shaft associated with the second grasping arm to another shaft. The handle assembly may further include a toggle actuation assembly that is operable to grasp and release a needle with the grasping arms. A locking feature may be included to prevent use of the toggle actuation assembly until trigger-operated actuation assembly has been operated.

Abstract: A lattice stitch surgical tension-limiting device, designed to be used in lattice stitch repair of wounds in biologic tissue. The device is tied to the surface of biologic tissue to be repaired by a lattice stitch. The device is designed to limit the tension in the lattice stitch, to allow placement of the lattice stitch without the need of an assistant and “instrument tie”, to help displace tension away from the surface of the body tissues, to enhance the properties of the lattice stitch in tissue shear reduction, and manage rotational forces affecting the repair as the lattice stitch draws the wound together to a closed condition. The device remains on the tissue surface during the wound healing period and is removed with the lattice stitch when wound healing is complete.

Abstract: A knotless suture system formed from two lengths of suture joined at a suture junction point, with at least four suture limbs extending from the suture junction. The knotless suture system provides the ability to construct a suture bridge for soft tissue repair and fixation across a medial and lateral row bone fixation anchor configuration while passing the suture system in a simplified method of suture management.

Abstract: A nonwoven compensator for an end effector of a surgical instrument can comprise a plurality of spring fibers dispersed throughout the nonwoven compensator. The nonwoven compensator can be positioned in the end effector such as adjacent to a deck surface of a fastener cartridge that is positioned in the end effector. When a fastener from the fastener cartridge is moved from an initial position to a fired position, the fastener can be configured to engage the nonwoven compensator. The fastener can compress a portion of the nonwoven compensator in a staple entrapment area defined by the fired staple. The spring fibers in the nonwoven compensator can comprise a resilient material and can be deformed when the fastener compresses a portion of the nonwoven compensator. Further, the nonwoven compensator can comprise non-spring fibers, a haemostatic material, and/or a homogenous absorbable polymer matrix.

Abstract: The present invention relates to a reflux disease treatment apparatus, apparatus, comprising an implantable movement restriction device that maintains cardia in the correct position and an implantable stimulation device adapted to engage with the cardia sphincter of a patient. The invention further comprises a control device for controlling the stimulation device to stimulate the cardia sphincter. The invention can be combined with various methods for treating obesity, in particular methods that creates satiety by stretching the wall of the stomach or fills out a volume of the stomach.

Abstract: Methods and devices for modifying the location at which bodily fluids interact with nutrients in a gastrointestinal tract. The methods and devices utilize a conduit configured to divert bodily fluids from an entrance within a gastrointestinal tract to a location downstream from the entrance.

Abstract: An apparatus for joining two hollow organ sections with an annular array of surgical staples includes a staple cartridge component, an anvil component, a buttress component and a fastening member. The staple cartridge component includes a plurality of surgical staples arranged in an annular array. The anvil component is movable relative to the staple cartridge component between spaced apart and approximated positions to adjustably clamp the organ sections between the staple cartridge and anvil components. The buttress components are configured and dimensioned to be positioned on a distal surface of the staple cartridge component and the proximal surface of the anvil component. In particular, the buttress component includes a buttress member and a plurality of circumferentially arranged tabs extending proximally from the buttress member.

Abstract: A catheter and related methods for percutaneous treatment of an aneurysm. The present catheters include an outlet for deploying an occluding agent; and a deflector for deflecting the occluding agent. A second deflector may be provided to cooperate with the first deflector. One or both of the deflectors may each include an inflatable balloon. The occluding agent may include a length of wire.

Abstract: Implantable therapeutic devices and methods for endovascular placement of devices at a target site, such an opening at a neck of an aneurysm, are disclosed. Selected embodiments of the present technology have closures (102) that at least partially occlude the neck of an aneurysm to stabilize embolic or coagulative treatment of the aneurysm. In one embodiment, for example, an aneurysm closure device comprises a closure structure (102) and a supplemental stabilizer (103). The closure structure can have a curved portion configured to extend along a first vessel, such as a side branch of a bifurcated vessel that extends along a lateral axis (T). The supplemental stabilizer extends from the closure structure along a longitudinal axis (L) transverse to the lateral axis of the first vessel. The supplemental stabilizer is configured to exert an outward force against a second vessel, such as a parent vessel, that extends transversely to the first vessel.

Abstract: This document provides novel drills and/or reamers that are well-suited for making holes in a variety of materials including, but not limited to, metals, ceramics, glass, wood, plasterboard, plastics, stone, composites, synthetics, silicon or multi-layered or hybridized substrates. In some embodiments, these drilling devices have some centers of mass that are offset from the axis of rotation. Accordingly, such drills and/or reamers may rotate and cut using a precessional pattern of motion. Precessional cutting devices may display a mechanical wave pattern in relationship to the longitudinal axis of the device. If the cutting device is fabricated from a flexible material, for example Nickel-Titanium, bodily deflection of the device may result during rotation.

Abstract: A drill sleeve includes a lower end that engages a bone being drilled with a drill bit of a drill during an orthopedic procedure, an upper end that is movable with respect to the lower end, and a fluid damper between the upper and lower ends for resisting movement of the upper end with respect to the lower end and which may reduce a distance at which a drill bit can plunge through a back side of the bone by increasing resistance to drill movement at occurrence of plunge through the back of the bone. The drill sleeve may include measurement scale and a lock that prevents relative motion of the upper and lower ends after the bone has been drilled for evaluating a position of a depth indicator with respect to the measurement scale that corresponds to a depth of the bore in the bone.

Abstract: A minimally-invasive bone graft harvesting device, kit, and method are provided. The device includes a hollow cutting element and an extraction element. The hollow cutting element may define a longitudinal axis and includes a distal end, a proximal end adapted to be coupled to a powered or manual-operated rotary tool, and an inner lumen extending longitudinally between the distal and proximal ends. The hollow cutting element may also include one or more blades protruding from an outer surface of the cutting element. Each blade may be arranged adjacent to an opening extending between the outer surface and the inner lumen to allow cancellous bone material cut by each blade during use to pass through the opening into the inner lumen. The extraction element may be removably received within the inner lumen of the hollow cutting element to allow withdrawal of the bone material in the inner lumen.

Abstract: A dilation introducer for orthopedic surgery is provided for minimally invasive access for insertion of an intervertebral implant. The dilation introducer may be used to provide an access position through Kambin's triangle from a posterolateral approach. A first dilator tube with a first longitudinal axis is provided. An access cannula may be introduced over the first dilator tube. A drill may be inserted through the access cannula and used to perform a foraminoplasty. Surgical instruments may pass through the access cannula to operate on an intervertebral disc and/or insert an intervertebral implant.

Abstract: Disclosed is an apparatus for forming an arcuate channel in one or more segments of a bone, bony structure or adjacent vertebrae of a spine. The apparatus includes, inter alia, a base member which is positioned proximate to the surgical site, a support arm extending proximally from the base member, an arcuate guide member and a drill assembly. The arcuate guide member is slidably mounted to the support arm. The drill assembly is operatively coupled to the support arm and includes a drill bit attached to the distal end of a flexible drive cable. The flexible drive cable extends axially along the support arm and is axially and rotationally movable with respect thereto. The drill bit is operatively coupled to an end of the arcuate guide member such that when the drill assembly is moved distally, the arcuate guide member slides with respect to the support arm and forces the drill bit to traverse an arcuate path.

Abstract: An endplate for an intervertebral prosthesis includes an inner domed region and a peripheral rim wherein the inner domed region has a non-circular plan and has an area that is at least 50% of the area of the endplate. A surgical instrument for milling a recess in a vertebral endplate includes a cutting tool having a drive shaft with a positioning collar, a guard frame, and a pair of guide plates attached to the guard frame and spaced to confine the positioning collar and having guide slots for the drive shaft.