CERVIMETRY CONTROL APPARATUS

BACKGROUND OF THE INVENTION

During the later stages of pregnancy, the cervix typically undergoes numerous physical changes which provide increased safety and ease with which the fetus can be delivered. Particularly, the cervical canal tissue softens and increases in pliability, and subsequently, the diameter of the cervical canal begins to increase. Eventually, the dilation of the cervix is completed, allowing for the unobstructed passage of the fetus.

Cervical diameter is monitored throughout labor and is instrumental in diagnosing such conditions as dysfunctional or arrested labor, to determine whether labor augmentation or a cesarean section should be performed, as well as to establish whether or when various pharmaceutical agents should be administered. Physical examination of the cervical diameter is generally performed by inserting two fingers into the vagina and up to the cervix. Upon reaching the cervix, the fingers are spread apart to determine the approximate dilated diameter. While an obstetrician may be fairly experienced in performing a manual cervical diameter measurement, the accuracy of such a measurement can be highly subjective and can further vary depending on the particular experience, judgment, and even finger size of the attending physician. Considering the importance of the cervical dilation measurement in assessing labor progression, it is crucial to provide dilation information that is precise as well as reproducible among different healthcare providers or physicians.

Given the subjectivity and probability of inaccurate or imprecise dilation measurements, it would be desirable to provide for the precise and accurate attainment of cervical dilation measurements on a repeat basis during the course of labor. In addition, it would be desirable to provide for ease of monitoring and control of cervical dilation to assist a physician throughout labor management.

SUMMARY OF THE INVENTION

The present invention advantageously provides a method and system for the accurate and precise measuring of cervical dilation during labor, as well as a method and system for performing cervical dilation. The medical device of the present invention may include an elongate body defining a proximal end and a distal end, with the elongate body further including an inflation lumen. An expandable element

may be coupled to the elongate body in fluid communication with the inflation lumen, and an array of movable elements may be circumferentially disposed about the elongate body, with the array of movable elements being movably coupled to the elongate body by a plurality of wires. The medical device may also include a measurement mechanism able to determine a radial spacing of the array of movable elements, where the measurement mechanism can include a tension ring coupled to the plurality of wires. In addition, a dilation indicator can be provided in communication with the measurement mechanism, while at least one pressure sensor may be coupled to at least one of the array of movable elements. Moreover, a distal pressure sensor can be coupled to the distal end of the elongate body, with the medical device also providing a control element in communication with the at least one pressure sensor and the distal pressure sensor. The medical device can also include an inflation source in fluid communication with the expandable element, as well as an exhaust valve in fluid communication with the expandable element. Furthermore, the medical device may include a camera as well as a lighting element coupled to the distal end of the elongate body, thereby providing visual feedback to aid in the positioning of the device.

The control element of the present invention may further provide for monitoring and controlling the operation of the medical device. The control element may be in communication with the one or more sensors disposed on the medical device, as well as being in communication for control and/or monitoring of the additional components of the medical device, such the camera, lighting source, inflation source, or the like. The control element may provide a display or other indication elements for conveying information, such as pressure, size, etc. to a physician during a particular procedure. Moreover, the control element may provide for additional patient safety by having an automatic alarm and/or shut down process in response to measurements and/or conditions that differ from a pre-determined set of parameters.

In an alternative embodiment, the present invention also provides a cervical dilation sensor to aid in the manual, two-finger approach commonly employed. The cervical dilation sensor may include a first rod, a second rod, and a sensor housing. The first and second rods may be rotatably and pivotably coupled to the sensor

housing, as to freely move about the housing in at least two planes of motion. The sensor housing may include one or more sensors coupled to the first and second rods as to measure the relative movement of the two rods, while the cervical dilation sensor may also include a control monitor in communication with the one or more sensors in the sensor housing for displaying and monitoring information provided by the sensors.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

FIG. 1 is an illustration of an embodiment of a medical device in accordance with the present invention;

FIG. 2 is a side view of a distal end of the medical device of FIG. 1;

FIG. 3 is a cross-sectional view of a distal end of the medical device of FIG. 1;

FIG. 4 is an additional cross-sectional view of the medical device of FIG. 1;

FIG. 5 is a cross-sectional view of an embodiment of a dilation indicator in accordance with the present invention;

FIG. 6 is an illustration of an embodiment of a control element in accordance with the present invention;

FIG. 7 is an illustration of a distal end of a medical device in a deflated state in accordance with the present invention;

FIG. 8 is an illustration of a distal end of a medical device in an inflated state in accordance with the present invention;

FIG. 9 is a flow chart of an embodiment of a method of use of a medical device of the present invention;

FIG. 10 is a perspective illustration of an embodiment of a cervical dilation sensor in accordance with the present invention;

FIG. 11 is a side view of the cervical dilation sensor of FIG. 10;

FIG. 12 is an additional illustration of the cervical dilation sensor of FIG. 10;

FIG. 13 is yet another depiction of the cervical dilation sensor of FIG. 10.

FIG. 14 shows an embodiment of a cervical dilation sensor coupled to a hand;

FIG. 15 depicts an embodiment of a cervical dilation sensor within a glove;

FIG. 16 illustrates an additional embodiment of a cervical dilation sensor coupled to a hand;

FIG. 17 shows an embodiment of a calibration element for use with a cervical dilation sensor in accordance with the present invention; and

FIG. 18 is a flow chart of an embodiment of a method of use of a cervical dilation sensor in accordance with the present invention;

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIG. 1, the present invention provides a medical device 10 for measuring and performing cervical dilation. The medical device 10 includes an elongate body 12 defining a proximal end 14 and a distal end 16. The medical device 10 may further include a dilation indicator 18 coupled to the proximal end 14 of the elongate body 12 that is capable of providing a visual indicator of the dilation measurement made by the medical device 10, as well as a control element 20 and an inflation source 22, which will be discussed in more detail below.

Now referring to FIG. 2, the medical device 10 may further include an array of movable elements 24 disposed circumferentially about an axis of the elongate body 12, where the array of movable elements 24 is located in proximity to the distal end 16 of the elongate body 12. The array of movable elements 24 are movable in a radial direction as to expand and contact with the tissue of the cervix when positioned for measurement of cervical dilation. Moreover, the array of movable elements 24 may be retracted upon completion of the desired measurement to ease the withdrawal of the medical device 10 from the patient. Each movable element may define an upper portion 26 and a lower portion 28. In addition, each movable element may define a channel 30 such that one or more pressure sensors 32 may be mounted or otherwise positionable within the channel 30 of the movable element. Moreover, an outer cushion 34 may be coupled to an outer surface of each movable element, where the outer cushion 34 may be constructed from a gel-like material or other suitable padding. The array of movable elements 24 may further be movably coupled to the elongate body 12 of the medical device 10 by a plurality of wires 36 coupled to the upper and lower portions of the movable elements 24, where the plurality of wires 36 further extend through a length of the elongate body 12.

While the array of movable elements 24 may be extended and retracted by manipulating the plurality of wires 36, an actuating mechanism may be provided to facilitate movement of the array of movable elements 24 from a retracted position to an extended position, and vice versa. The actuating mechanism may include a spring mechanism, a telescoping element, or, alternatively, the medical device 10 may include an expandable element 38, such as a balloon. Now referring to FIG. 3, the medical device 10 of the present invention may further include the expandable element 38 coupled to or otherwise disposed on the elongate body 12 at or near the distal end 16 of the elongate body 12. The expandable element 38 maybe configured in a myriad of shapes, including a toroidal configuration in which the expandable element 38 defines a ring-like, "O" shape. Moreover, an inflation lumen 40 can be included in fluid communication with the expandable element 38, where the inflation lumen 40 is disposed within and traverses a substantial length of the elongate body 12.

The medical device 10 of the present invention may include additional features providing safety, ease of use, and the like. For example, the medical device 10 may include a protective sheath 42 encasing at least a portion of the distal end 16 of the elongate body 12. The sheath 42 may include one or more layers of various materials to provide a water-tight seal around the medical device, as well as adding to patient comfort by having additional padding and/or a lubricious coating to ease positioning of the device. For example, a first layer may completely enclose the medical device to ensure the device is not exposed to external fluids or objects. A second layer may be placed over the first layer as a protective layer which is removable by a physician or operator after each use, thereby providing a sterile layer and the possibility for re-use of the medical device. A third layer may be provided over the second layer and include a lubricious property allowing for smooth insertion, operation, and removal of the device.

Furthermore, a distal pad 44 may be coupled to the elongate body 12 at or near the distal end 16, where the distal pad 44 may be contoured or shaped to conform to the curvature of the head of a baby. In addition, a distal pressure sensor 46 may be coupled to the distal pad 44 to aid in monitoring the positioning of the medical device 10 and for determining contact with the cervix or with the baby. The distal pad 44

and distal pressure sensor 46 may provide feedback to a physician and aid in the axial positioning of the medical device 10 upon insertion into a patient. Furthermore, a camera 45 and a lighting element 47 may also be coupled to the distal portion of the medical device. The camera 45 may be a miniaturized instrument or pin-hole camera as commonly employed in endoscopic surgical procedures, while the lighting element 47 may include a diode, fiber optic, or other illumination mechanism as is known in the art. The camera 45 and lighting element 47 may provide visual feedback to a physician to further aid in maneuvering and positioning the medical device when in use.

As shown in FIG. 4, the elongate body 12 may define a plurality of wire lumens 48 for slideably receiving a portion of each of the plurality of wires 36 coupled to the array of movable elements 24. Each wire of the plurality of wires 36 may be slideably positioned within each of the plurality of wire lumens 48 as to slide freely with little friction, thereby facilitating the movement of the array of movable elements 24 when the medical device 10 is in use. The wires 36 may have sufficient length as to extend through the entire length of the respective wire lumens 48, and may further extend out of the proximal end 14 of the elongate body 12.

The medical device 10 of the present invention may further include a measurement mechanism for monitoring and / or quantifying the movement of the array of movable elements 24 when the medical device 10 is in use. For example, as shown in the FIG. 5 illustration of a cross-section of the dilation indicator 18, the medical device 10 may include a tension ring 50 coupled to the plurality of wires 36 such that the tension ring 50 moves as the wires 36 extend and retract in response to the movement of the array of movable elements 24. The tension ring 50 may further be slideably coupled to the dilation indicator 18, where the dilation indicator 18 conveys a dilation measurement in response to the relative motion of the tension ring 50, the plurality of wires 36, and thus, the array of movable elements 24. The dilation indicator 18 may include predetermined values calculated from the movement of the tension ring 50 as to eliminate the need for a physician to do any calculating to determine the dilation measurement.

Again referring to FIG. 1, in an exemplary system, the proximal end 14 of the medical device 10 of the present invention is coupled to the control element 20,

through which a physician may monitor and/or control the various components of the medical device 10. The control element 20 may be in communication with any of the numerous sensors provided on the medical device 10, and may further be in communication with additional components of the medical device 10, such as the inflation source 22, the camera 45, and/or the lighting element 47. In an exemplary embodiment, the control element 20 may include a console that may be wrist- mounted to ease the overall use of the medical device 10.

The control element 20 may include a display, such as an LCD screen or the like, as well as other visual, audio, or tactile indicators to convey information regarding the various operating characteristics and conditions of the medical device 10 to an operator or physician, including dilation measurements, dilation pressure exerted by the medical device, inflation pressure, etc. The control element 20 may further include one or more control actuators, such as push-buttons, switches, a touchscreen, or the like, to enable a physician to provide input to the control element in order to manipulate and/or control a particular component or function of the medical device 10.

In addition, the control element 20 may include a processor component and an electronic storage medium (not shown) for storing patient information, measurements and/or procedural information obtained during use of the medical device. The control element 20 may provide calculations and graphical illustrations including, but not limited to, a display of air pressure versus time, air pressure versus diameter, upper and lower limits of expansion pressure, etc. The control element 20 may further contain date/time information for measurements, the physician or nurse performing the procedure, and the like. Moreover, the control element 20 may be able to communicate such recorded information to other devices and/or systems in the hospital environment through the use of portable media and/or wireless technologies as is known in the art.

In an exemplary embodiment, as shown in FIG. 6, the control element may include a housing including an visual display 52, a plurality of LEDs 54, and a plurality of control actuators 56 (shown as push buttons) which may be in communication with the camera 45, light 47, and/or the inflation source 22, as previously described. In addition, the housing of the control element 20 may be

mounted on the wrist of a physician through one or more coupling elements 58. Moreover, to further ease use, the visual display 52 may be movably coupled to the housing so that a physician may change the viewing angle or orientation of the screen during use of the medical device. A particular use of the control element 20 during a cervical procedure with the medical device is described further below.

The inflation source 22 of the medical device may be coupled to the inflation lumen 40 at the proximal end 14 of the elongate body 12, where the inflation source 22 is able to provide a fluid or gas into the inflation lumen 40 for subsequent delivery to the expandable element 38. Examples of a suitable inflation source 22 may include manual pumps, powered pumps, or the like. The inflation source may be either separate from the control element, as shown in FIG. 1, or integral with the control element 20 as shown in FIG. 6. Moreover, an exhaust valve 60 may be in fluid communication with both the inflation source 22 as well as the inflation lumen 40 for subsequent control of the release of fluid from the medical device 10, and may further be in communication with and/or controlled by the control element 20.

Referring now to FIGS. 7 and 8, in an exemplary use of the medical device 10 of the present invention, a precise dilation measurement may be performed during the various stages of labor. The medical device 10, in a deflated state, may be positioned such that the distal end 16 of the elongate body 12 is in proximity to the dilated region of the cervix 54. Proper positioning can be aided by feedback provided by the distal pressure sensor 46 when contacting the cervix or the head 56 of the baby, as well as monitoring the visual feedback from the camera 45. The sensor feedback as well as images obtained by the camera 45 may be displayed on the LCD screen of the control element. Upon proper positioning, the array of movable elements 24 may be extended to contact the tissue of the cervix 54, for example, by actuating the inflation source 22 to inflate the expandable element 38. As the expandable element 38 is inflated and subsequently expands, the array of movable elements 24 located around the periphery of the expandable element 38 will move outward in a radial direction, while lengths of the plurality of wires 36 will be drawn further into the respective plurality of wire lumens 48. As the array of movable elements 24 is coupled to the plurality of wires 36, which are further coupled to the tension ring 50, the expandable element 38 will expand outward uniformly from the elongate body 12.

The inflation source 22 may continue to inflate the expandable element 38 until the movable elements 24 of the medical device 10 come into contact with the dilated or undilated cervix 54. Such contact can be indicated and monitored through information provided by the pressure sensors 32 coupled to the movable elements 24, which, again, may be relayed to a physician or operator through the control element. In particular, the control element may provide a visual indicator of the pressure being exerted on the cervical tissue by the expansion of the medical device as well as the overall dilation measurements of the cervix. Furthermore, the control element 20 may include an algorithm or computational ability to determine if the pressure sensor feedback indicates a substantially uniform circular state. That is to say, that the pressure measurements from each of the pressure sensors 32 disposed about the movable elements 24 are approximately the same. When the desired inflation level or diameter has been attained as indicated by pressure sensor measurements or from the dilation indicator, the inflation source 22 may be deactivated, or, alternatively, the exhaust valve 60 may be triggered to prevent additional fluid from entering the expandable element 38. Each of these events may be triggered and/or controlled by actuator elements included on the housing of the control element.

Once appropriately inflated, the measuring mechanism and the dilation indicator 18 can provide the dilation measurement as indicated by the distance the plurality of wires 36, and thus the tension ring 50, traveled in reaching the expanded state. As previously stated, the dilation indicator 18 can directly correlate the distance traveled by the wires 36, and thus, the measured expansion of the movable elements 24, to an accurate and precise dilation measurement.

Upon completion of the desired measurement, the movable elements 24 are retracted towards the elongate body 12, i.e., by deflating the expandable element 38 by opening the exhaust valve 60, upon which the movable elements 24 will retract to a closed position for the removal of the medical device 10 from the patient. Both the tension ring 50 and the plurality of wires 36 may be biased towards a closed, retracted position, such that when the expandable element 38 is not under positive inflation pressure, the medical device 10 retains a closed, retracted state. Furthermore, as described above, the medical device 10 may include an outer sheath 42 which, if used, may be removed and replaced for subsequent uses of the medical device 10, thereby

providing a re-usable device while maintaining the sterility of the medical environment.

Referring to FIG. 8, in an alternative use of the medical device 10 of the present invention, the distal portion of the medical device 10 may be employed to produce a safe and uniform cervical dilation where a desired dilated condition has not yet occurred or otherwise been achieved. The medical device 10 may be positioned proximate to a region of an undilated cervix and the array of movable elements 24 of the medical device 10 may be expanded to contact the cervical tissue 54. Similar to obtaining a dilation measurement as described above, the distal pad, pressure sensors or camera may provide feedback to a physician or operator to aid in the axial positioning of the device. Through monitoring information from any of the aforementioned components, through the control element for instance, the medical device may traverse the length of the cervix while reducing the likelihood of accidentally perforating the uterus, which may occur with the use of conventional devices. ^r

Upon initiating the desired contact, the array of movable elements 24 may then be extended further, for example, through a controlled inflation of the expandable element 38, in order to provide a desired rate of expansion, and thus, dilation. Alternatively, the array of movable elements may be actuated to extend outward through pressure or force applied through the plurality of wires 36, or by other actuating mechanisms as known in the art. At any point during the dilation procedure, information may be provided regarding the amount of force being applied to the cervical tissue via the one or more pressure sensors 32 coupled to the array of movable elements 24, as well as the radial spacing of the array of movable elements. As such, through the monitoring of sensor feedback information, the dilating force applied to the array of movable elements either through the plurality of wires 36 or by the expandable element 38 may be appropriately adjusted in order to achieve the desired dilation without unnecessarily damaging the cervical tissue. Additionally, the spacing of the array may be monitored to achieve a desired dilated state. Through the monitoring and manipulation of the operating characteristics of the medical device, including the rate of extension of the array, the pressure between the medical device

and the tissue, and/or the distance traveled and thus the radial spacing of the array, a precise and accurate dilation may be induced.

The above-described dilation may be performed for obstetrical uses, for example, in cervical "ripening" to assist in the induction of labor in cases of poorly dilated or effaced cervices, hi addition, pre-operative dilation may be performed using the medical device of the present invention in cases of uterine curettage for failed pregnancy, miscarriage, or retained products of conception. Moreover, the medical device may be used for gynecological purposes of cervical dilation in cases of curettage of the endocervix or endometrium, elective termination of pregnancy, diagnostic and operative hysteroscopy, thermal endometrial ablation techniques, as well as treatment of cervical stenosis.

While it has been discussed that the control element may provide a variety of information from the numerous sensors and other components to a physician or operator during the above-mentioned procedures, the control element may further provide for enhanced safety during use by including pre-determined circumstances and/or threshold values for safe operation, irrespective of whether the aim is to take measurements or to cause dilation. Now referring to FIG. 9, for example, the medical device may be positioned initially in the cervix, while values obtained from the distal pressure sensor are monitored. Should a particular pressure be experienced that exceeds a pre-determined safe operating pressure that could damage the baby or surrounding tissue, the control element 20 may provide an audio, visual, or tactile alarm to the operator to withdraw the device. Upon proper positioning, the inflation source 22 may be actuated. Should a pressure in the inflation lumen, RPM, or other indicator of the operation of the inflation source 22 differ from expected values, the control element 20 may again cause an alarm and/or automatically terminate operation of the inflation source 22. Similarly, during use of the medical device 10, if the pressure being exerted on the cervical tissue during expansion is greater than desired, or should the diameter of the expanded portion of the medical device appear out of the desired range, the control element 20 may convey these circumstances through visual, audio or tactile indicators and/or initiate a shut-down sequence of events, which may include deflation, retracting the array or movable elements, etc.

Now referring to FIGS. 10-13, in an alternative embodiment of the present invention, a cervical dilation measurement device 100 is provided to aid in the manual, two-finger approach of measuring cervical dilation. The measurement device 100 may include a first extension element 102, a second extension element 104, and a base element 106. The first and second extension elements 102,104 may be rotatably and pivotably coupled to the base element 106, as to freely move about the housing in at least two planes of motion. The base element 106 may include a dilation indication mechanism to measure the distance between and/or the relative movement of the two extension elements. The dilation indication mechanism may include one or more sensors coupled to or otherwise in communication with the first and second extension elements 102,104. Sensors suitable for monitoring the movement of the first and second extension elements 102,104 may include sensors mechanically coupled to the extension elements capable of measuring their displacement or movement directly, including but not limited to torque or strain gauges, or may alternatively include sensors positioned in the tips of the first and second extension elements that can monitor distance between the two tips via radiofrequency, optical energy, or the like. A third sensor may be incorporated, in the base element 106 for example, to provide increased accuracy and precision through triangulation methods. The measurement device 100 may also include the control element 20, as previously described and illustrated in FIG. 1, in communication with the base element 106 and one or more sensors for displaying and monitoring information provided by the sensors.

Now referring to FIGS. 14-16, the measurement device 100 of the present invention may also include one or more lateral sensors 108,108' positionable about the sides of the first and second fingers used in the manual cervical dilation measurement technique. The lateral sensors 108,108' may provide pressure feedback information when in contact with the cervix that may assist a physician in making a measurement while avoiding or minimizing cervical distension. As such, the reduced likelihood of cervical distension increases the ability to provide an accurate and precise dilation measurement. The lateral sensors 108,108' may include one or more thin film pressure sensors, as known in the art, to minimize the increase in width or thickness of the device, thereby providing ease of use and reducing discomfort of the patient, and may further be placed in communication with the control element 20.

The measurement device 100 of the present invention may also include one or more finger-tip pressure sensors 110,110' positionable about the tips of the first and second fingers used in the manual cervical dilation measurement technique. The finger-tip pressure sensors 110,110' may indicate pressure feedback information via the control element 20 upon contact with the head of the baby. In addition to providing feedback information to prevent excess pressure on the head of the baby, upon recognition that the finger tips are indeed contacting the head of the baby, a marker or other measurement indicator may be used to gauge the position and descent of the baby, as described below.

Historically, practitioners have used the ischial spine as the index point (0 station) for a determination of fetal descent, and assigned an arbitrary number in centimeters above and below the ischial spine. More specifically, "station" refers to the level of the presenting fetal part in the birth canal as described in relationship to the ischial spines, which are halfway between the pelvic inlet and the pelvic outlet. When the lowermost portion of the fetal presenting part is at the level of the ischial spine, it is designated as being at zero (0) station. In the past, the long axis of the birth canal has been arbitrarily divided into segments for a determination of the position of the baby. Thus, as the presenting fetal part descends from the inlet toward the pelvic outlet, the typical designation is -5, -4, -3, -2, -1, 0 station, +1, +2, +3, +4, +5. Using this method, the degree of accuracy (in centimeters) is difficult to achieve clinically. In practice, physicians may generally make an educated guess about the station of the presenting part of the baby, since after the "0" point (0 station), the baby's head covers the ischial spine point and eliminates the ability to measure and reproduce distance caudal to this point. Contrary to the typical method employed, where accuracy and precision may be difficult to maintain, the feedback from the finger-tip sensors may provide an indication of contact with the head of the baby. Upon such indication, a marking or other descent indicator 112 on the portion of the hand of the physician external to the genitalia may be used to provide an accurate and precise measurement of the location and descent of the baby. Measurements over the course of labor indicate rates of progression which are practical, relatively easier to standardize and explainable to the patient or other practitioners. This approach of measurement is termed "Advancement".

In an exemplary use, the measurement device 100 is coupled to the hand of a physician, with the first extension element 102 being paired to a first finger, the second extension element 104 being paired to a second finger, and the base element 106 being positioned in between the first and second fingers. Moreover, where the lateral sensors 108,108' or finger-tip sensors 110,110' are included, the sensors will be positioned about the sides and tips of the fingers, respectively, as described above. The coupling may be achieved through the integration of the measurement device 100 with a glove 114, or through direct adhesion of the various components to the fingers themselves. Additionally, the cervical dilation measurement device 100 may include two cap elements 116,116' positionable about the finger tips, with the first and second extension elements 102,104 extending from the cap elements 116,1 16' and towards the base element 106, and with the lateral and finger-tip sensors coupled to the cap elements in the appropriate positions. Any wires or other communicative elements connecting the sensors to the control element 20 may be routed through the glove or positioned down the back of the hand as needed to provide connectivity while preventing interference with the use of the device. Alternatively, the various sensors may communicate with the control element 20 wirelessly as known in the art.

Subsequently, the physician may position the first and second fingers and the cervical dilation measurement device 100 in proximity to the cervix. Upon reaching the desired location, the two fingers can be spread either into a "V" shape or an "L" shape, and the relative movement of the first and second extension elements 102,104 may be measured by the one or more sensors in the base element 106, with the lateral sensors 108,108' preventing cervical distension as previously described. As a result, the physician will not be required to make a subjective observation as to the actual cervical dilation, as the actual width between the spread fingers can be accurately assessed by the cervical dilation measurement device 100 and provided to the physician through the control element 20. In addition, upon contacting the head of the baby with the finger-tip sensors, the descent indicator 112 may be referenced to determine the location of the baby.

While the method of measurement as described above may provide an accurate and precise measurement of cervical dilation, it is realized that different physicians may have variations in both finger length and thickness which may affect

the accuracy of the measured dilation. Now referring to FIG. 17, the present invention may include a calibration element 120 for use with the measurement device 100 to compensate for the variations in the finger dimensions of a physician. The calibration element 120 may include an object of known dimensions, thereby providing a reference value from which the measurement device 100 may be calibrated. For example, the measurement device 100 may be coupled or otherwise positioned about the hand of a physician or operator, with the first extension element 102 being paired to a first finger, the second extension element 104 being paired to a second finger, and the base element 106 being positioned in between the two fingers. Subsequently, the first and second fingers may be extended such that an outer portion of the first and second fingers contact a portion of the calibration element 120, providing a "simulated" distance measurement. Upon contacting the calibration element 120, the first and second fingers will be separated by a known distance, and the relative movement of the first and second extension elements 102,104 about the base element 106 can be appropriately modified to reflect an accurate and precise measurement. Such modification may include, for example, an algorithm or other computational calculation taking into account the known, fixed dimensions of the calibration element 120, the known length of the first and second extension elements 102,104, as well as the angle formed between them at the intersection with the base element 106. The suggested calibration procedure may be performed a single time for each operator who may thereafter use the measurement device 100, and such values and calibration modifications may be stored in the control element 20 for ease of subsequent use without the need to re-calibrate the device. Alternatively, the suggested calibration procedure may be performed prior to each dilation measurement to ensure accuracy and precision.

As discussed above, the control element 20 may be coupled to the measurement device 100 similarly to that of the medical device 10 in order to provide a variety of information from the numerous sensors and other components of the measurement device 100 to a physician or operator during the above-mentioned procedures. Once again, the control element 20 may further provide for enhanced safety during use by including pre-determined circumstances and/or threshold values for safe operation, irrespective of whether the aim is to take measurements or to cause

dilation. Now referring to FIG. 18, for example, the measurement device 100 may be initially positioned in the cervix, while values obtained from the finger-tip sensors 110, 110' are monitored. Should a particular pressure be experienced that exceeds a pre-determined safe operating pressure that could damage the baby or surrounding tissue, the control element 20 may provide an audio, visual, or tactile alarm to the operator to withdraw the device. Upon proper positioning, the operator or physician may expand their fingers. Subsequently, during use of the measurement device 100, if the pressure being exerted on the cervical tissue during expansion is greater than desired as indicated or otherwise measured by lateral sensors 108, 108', or should the diameter of the expanded fingers as measured by the measurement device 100 appear out of the desired range, the control element 20 may convey these circumstances through visual, audio or tactile indicators, upon which the physician or operator may close and retract their fingers and the accompanying measurement device 100.

It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings without departing from the ope and spirit of the invention, which is limited only by the following claims.