This review discusses advances in knowledge regarding the composition and structure of bone, the modeling and remodeling of bone, the formation of bone during growth and its reconstruction in adults, and how age-related abnormalities in these processes compromise the composition and structure of bone.

Bone Quality — The Material and Structural Basis of Bone Strength and Fragility

A system for performing minimally invasive cardiac procedures. The system includes a pair of surgical instruments that are coupled to a pair of robotic arms. The instruments have end effectors that can be manipulated to hold and suture tissue. The robotic arms are coupled to a pair of master handles by a controller. The handles can be moved by the surgeon to produce a corresponding movement of the end effectors. The movement of the handles is scaled so that the end effectors have a corresponding movement that is different, typically smaller, than the movement performed by the hands of the surgeon. The scale factor is adjustable so that the surgeon can control the resolution of the end effector movement. The movement of the end effector can be controlled by an input button, so that the end effector only moves when the button is depressed by the surgeon. The input button allows the surgeon to adjust the position of the handles without moving the end effector, so that the handles can be moved to a more comfortable position. The system may also have a robotically controlled endoscope which allows the surgeon to remotely view the surgical site. A cardiac procedure can be performed by making small incisions in the patient's skin and inserting the instruments and endoscope into the patient. The surgeon manipulates the handles and moves the end effectors to perform a cardiac procedure such as a coronary artery bypass graft.

Method and apparatus for performing minimally invasive cardiac procedures

A robotic system that moves a surgical instrument in response to the actuation of a foot pedal that can be operated by the foot of a surgeon. The robotic system has an end effector that is adapted to hold a surgical instrument such as an endoscope. The end effector is coupled to a robotic arm assembly which can move the endoscope relative to the patient. The system includes a computer which controls the movement of the robotic arm in response to input signals received from the foot pedal.

Automated endoscope system for optimal positioning

This invention is a surgical system (10) that may include a remotely controlled surgical instrument. The surgical instrument may be coupled to a tool driver (1602) that can spin, and actuate the instrument. The instrument may include an actuator rod that is coupled to an end effector (1710), and detachably connected to a push rod (1654). The push rod (1836) can move relative to the handle to actuate the end effector. The end effector may include a fixture that conforms to the shape of a needle (1712). The handle (1812) can be secured to the tool driver by inserting pins into corresponding slots that are located on both the instrument and the tool driver. The instrument can be controlled by an operator through a pair of handles (1806). Each handle may be mechanically balanced by a counterweight. The surgical system may also include a touch pad (1808) that allows the operator to enter parameters of the system.

Method and apparatus for performing minimally invasive surgical procedures

An image guided catheter navigation system for navigating a region of a patient includes an imaging device, a tracking device, a controller, and a display. The imaging device generates images of the region of the patient. The tracking device tracks the location of the catheter in the region of the patient. The controller superimposes an icon representing the catheter onto the images generated from the imaging device based upon the location of the catheter. The display displays the image of the region with the catheter superimposed onto the image at the current location of the catheter.

Navigation system for cardiac therapies

During surgery, a physician speaks commands that are received by a microphone (10). A speech processor (12) converts audio signals from the microphone into word signals. A command interpreter (14) compares each word signal with a list of previously authorized command words. When the word signal corresponds to one of the preselected command words, a corresponding command signal is generated and sent to a volume imager (18), a video recorder (20), a hard copy, printer (28), or other system component. The volume imager generates an image representation signal indicative of a portion of image data stored therein which is displayed on a video monitor (B) or recorded on the video recorder.

Voice actuated volume image controller and display controller

A diagnostic imaging system generates a three-dimensional display from a series of two-dimensional slice images. A region of interest, defined from a boundary of interest, is selected from one slice and is extrapolated to subsequent slices. Pixels representative of the boundary of interest are isolated and represented by three vectors having an equivalent entries in each. First and second vectors store data representative of first and second coordinates for pixels within each slice. Entries in the third vector corresponds to physical properties of a specimen at a location defined by corresponding entries in the first and second vectors. Areas representative of boundaries of interest falling between slices are extrapolated from vector data from slices neighboring the area. This is accomplished by a linear interpolation of elements of the set of smaller vectors to a number equivalent to the entries in the neighboring larger vectors. Next, a linear extrapolation between respective elements of the lengthened vector and the longer of the vector is made. Finally, a linear interpolation of the intermediate vector to a number of vector elements intermediate the larger and smaller of the neighboring vectors is made. This process is suitably continued during a preselected number of iterations. Finally, a discretized three-dimensional object represented by all sets of first, second, and third vectors are mapped to pixels of an associated pixel frame.

Quick three-dimensional display

Contiguous high resolution computed tomography images were obtained at a 1.5 mm slice thickness perpendicular to the neck axis from the base of the femoral head to the trochanteric line in a sample of 10 specimens each of Homo sapiens, Pan troglodytes, and Gorilla gorilla, plus five specimens of Pan paniscus. Superior, inferior, anterior, and posterior cortical thicknesses were automatically measured directly from these digital images. Throughout the femoral neck H. sapiens displays thin superior cortical bone and inferior cortical bone that thickens distally. In marked contrast, cortical bone in the femoral neck of African apes is more uniformly thick in all directions, with even greater thickening of the superior cortical bone distally. Because the femoral neck acts as a cantilevered beam, its anchorage at the neck-shaft junction is subjected to the highest bending stresses and is the most biomechanically relevant region to inspect for response to strain. As evinced by A.L. 128-1, A.L. 211-1 and MAK-VP-1/1, Australopithecus afarensis is indistinguishable from H. sapiens, but markedly different from African apes in cortical bone distribution at the femoral neck-shaft junction. Cortical distribution in the African ape indicates much greater variation in loading conditions consistent with their more varied locomotor repertoire. Cortical distribution in hominids is a response to the more stereotypic loading pattern imposed by habitual bipedality, and thin superior cortex in A. afarensis confirms the absence of a significant arboreal component in its locomotor repertoire.

Cortical bone distribution in the femoral neck of hominoids: Implications for the locomotion of Australopithecus afarensis

A system for three-dimensional diagnostic imaging generates a plurality of slice images of a specimen. A region of interest is selected from within a slice and is extrapolated to subsequent slices. A boundary indicative of a surface of interest is selected from within the region of interest to facilitate generation of an image representative of a three-dimensional surface of interest to be assembled from subsequent slices of the plurality. A viewing surface is defined in relation to a generated surface image which was selected from the boundary. A scaling means assigns a scaled gray level to the three-dimensional image to facilitate three-dimensional viewing of the object when it is projected on the viewing surface. Image information is selectably modified by data from the original slice images to add surface density visualization. Means is also provided to facilitate selective segmentation of a three-dimensional image along a plane or planes of interest. An interactive procedure is provided to facilitate cutting of a three-dimensional object from its perspective view (with or without density information).

System to reformat images for three-dimensional display using unique spatial encoding and non-planar bisectioning

A source (A) of images, such as a CT scanner (10), a magnetic resonance imaging apparatus (12), and the like produces a plurality of basis images (I0, I1, I2, I3 . . . ). Two of the basis images are subtracted and divided (70, 72) by a number of interpolation increments (L1) to form a first differential image (I.sub.Δ1). The first and the third basis images are subtracted and divided (76, 78) by a number of available interpolation increments (L2) to form a second differential image (I.sub.Δ2). Four differential images are selectively combined and divided by a product of the first and second available increments (82, 84) to form a second order differential image (I2.sub.Δ12). An array of adders (D) selectively adds the first differential image to a currently displayed image stored in an image memory E each time a track ball (104) moves a cursor one increment in a horizontal position. Each time the track ball moves the cursor one increment up or down along the vertical column, the adder array adds or subtracts the second differential image to the currently displayed image. Each time the track ball steps the cursor between rows or between columns, the second order differential image is used to correct one of the first and second differential images. In this manner, only the currently displayed image, the first differential image, the second differential image, and the second order differential image need be stored to provide free interpolation among four basis images. The basis images themselves need not be stored.

Todd J. Krochta

Papers

Voice actuated volume image controller and display controller

Quick three-dimensional display

Cortical bone distribution in the femoral neck of hominoids: Implications for the locomotion of Australopithecus afarensis

System to reformat images for three-dimensional display using unique spatial encoding and non-planar bisectioning

Multi-parameter image display with real time interpolation