Scaled head frame positioner and tabletop adapter

A scaled head frame positioner and tabletop adapter are provided. The positioner may be employed for any neurosurgical procedure that requires fixed positioning of the stereotactic head frame or ring onto a patient's skull. The positioner employs a generally triangular shaped member with Velcro tapes fixed at each corner. The tapes have measurement markings, such as measurement tapes. The positioner supports the head frame with the tapes engaging means on the frame and fastened back to themselves, with markings indicating distances to adjust the position of the frame about the patient's head. Furthermore, the tabletop adapter clamps the patient with a stereotactic head frame onto a CT or treatment table. The tabletop adapter includes a generally U-shaped bracket secured to a support to be placed on the tabletop. The bracket is attachable to the head frame of the patient to hold his head in a desired position.

BACKGROUND

The present disclosure relates generally to stereotactic framework systems, and more particularly, to a scaled head frame positioner for positioning of a stereotactic frame head ring onto a patient's skull and tabletop adapter to clamp the patient with the stereotactic frame head ring onto a CT or treatment table.

2. Description of the Related Art

Procedures which involve surgery, radiation or other procedures performed on the brain or other intracranial structures are especially hazardous for the patient, because of the extreme sensitivity of brain tissues, the difficulty in identifying and accessing the particular portion of the brain upon which a procedure is to be performed, and the danger of damaging brain tissues which overlie or surround the portion upon which the procedure is to be performed. The desire for precisely locating and accessing interior portions of the brain and other intracranial structures have lead to the development of the neurosurgical subspecialty of stereotactic surgery or “stereotaxis.”

Stereotaxis ordinarily involves the use of an external apparatus attached to the patient's skull during presurgical diagnostic procedures and during surgical procedures. The apparatus provides a grid or framework in fixed position relative to the patient's skull which may be used to establish a coordinate system for locating, in a reproducible manner, the precise position of a lesion or other area within the intracranial area. The fixed framework also provides a structure external to the skull to which measuring devices, surgical instruments and the like can be attached and, by appropriate manipulation, positioned so they can be introduced to exact points within the intracranial structure. Surgical or other procedures then can be performed at an exact, predetermined, point within the brain or other tissue. The object of such devices is, ultimately, to permit safe impact at a predetermined location within the intracranial space for purposes such as excision, surgical biopsy, placement of catheters, installation of devices, removal of cysts, tumors or hematomas, or may involve focusing or direction of laser beams, radiation, magnetism or the like for diagnostic or treatment purposes.

The development of CAT scan technology, magnetic resonance imaging (MRI), angiography, digital subtraction angiography (DSA) and similar diagnostic procedures for producing images of structures contained within tissue has been applied to the field of stereotaxis to produce image-directed stereotaxis. A stereotactic apparatus is used in conjunction with advanced diagnostic imaging procedures to produce internal tissue images keyed to a cartesian or polar coordinate system. When the same stereotactic apparatus is utilized during surgery, it is possible to access a precise position inside the brain identified on the diagnostic images on the basis of the same coordinate system. For example, in stereotactic radiosurgery, consisting of a large dose of single fraction irradiation of a small intracranial target with radiation, a head ring of a stereotactic apparatus is positioned on the patient's head to ensure precise immobilization of the patient's head for imaging study and treatment.

Therefore, a need exists for techniques for easily and precisely positioning a head ring or frame of a stereotactic framework system to a patient's head so that the head ring or frame can be applied precisely in an exact position relative to the patient's head.

SUMMARY

A scaled head frame positioner and tabletop adapter are provided. The positioner of the present disclosure may be employed for any neurosurgical procedure that requires fixed positioning of the stereotactic head frame onto the patient's skull. The positioner employs a generally triangular shaped member with Velcro tapes fixed at each corner. The tapes have measurement markings, such as measurement tapes. The positioner supports the head frame with the tapes engaging means on the frame and fastened back to themselves, with markings indicating distances to adjust the position of the frame about the patient's head. Furthermore, the present disclosure provides for a tabletop adapter to clamp the patient with a stereotactic head frame onto a CT or treatment table. Unlike the prior art which uses plastic blocks to support the patient's head with the stereotactic head frame, the tabletop adapter includes a generally U-shaped bracket secured to a support to be placed on the tabletop. The bracket is attachable to the head frame of the patient to hold his head in a desired position.

According to one aspect of the present disclosure, an apparatus for easily and precisely fixing a frame head ring to a patient's head is provided, the apparatus including a rigid ring configured to have substantially the same diameter as the frame head ring, the rigid ring having a top surface and a bottom surface; a plurality of connectors disposed on and projecting from the bottom surface of the rigid ring, the plurality of connectors being adapted to coupled the rigid ring to the frame head ring; a support member for supporting the rigid ring upon the patient's head, the support member being adapted to come into contact with a top of the patient's head; and at least three adjustment members for coupling the rigid ring to the support member, the at least three adjustment members having scaled indicia for precisely adjusting the frame head ring relative to the patient's head.

According to another aspect of the present disclosure, an adapter for fixing a stereotactic frame head ring onto a CT or treatment table is provided, the adapter includes a generally, flat rectangular substrate configured to be disposed on a CT or treatment table and to support the patient on the CT or treatment table, the substrate having a top surface and a bottom surface; at least two connectors disposed on and projecting from the bottom surface of the substrate, the at least two connectors being adapted to coupled the substrate to the CT or treatment table; and a bracket disposed on one end of the substrate having at least two receiving members projecting perpendicular from the top surface of the substrate, the at least two receiving members configured for receiving screws of the head ring for fixing the head ring relative to the CT or treatment table.

DETAILED DESCRIPTION

Preferred embodiments of the present disclosure will be described hereinbelow with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail.

A scaled head frame positioner10in accordance with the present disclosure is generally shown inFIGS. 1-5. The positioner10of the present disclosure will help a user, e.g., a neurosurgeon, to stabilize a stereotactic head frame and to optimize the position of the head frame so that the neurosurgeon can fix the head frame onto the patient's skull with precision and ease. The positioner10further provides quantitative indications for adjustment via scaled tapes or straps so the head frame can be applied precisely in an exact position relative to the patient's head.

The positioner10includes a rigid ring12configured to have substantially the same diameter as the frame head ring14. The rigid ring12is generally flat and includes a top surface16and a bottom surface18. A plurality of connectors20are disposed on and projecting from the bottom surface18of the rigid ring12. The plurality of connectors20are adapted to coupled the rigid ring12to the frame head ring14as will be described in more detail in relation toFIG. 4. Each connector20includes a ball portion22and a stem portion24.

A support member26for supporting the rigid ring upon the patient's head is provided. The support member26is configured to come into contact with a top of the patient's head. At least three adjustment members28are provided for coupling the rigid ring12to the support member26. The at least three adjustment members28have scaled indicia for reproducibly and/or precisely adjusting the frame head ring relative to the patient's head. In one embodiment, each of the adjustment members28will include a loop and hook type fastener, e.g., Velcro, on one surface of the adjustment member so the adjustment member28may be threaded through bracket30of the rigid ring12and fasten back upon itself to secure the support member26to the ring12. The adjustment members28can take on other forms such as a strap and buckle and the like.

The adjustment members28will include on one surface scaled indicia31. By having scaled indicia on the adjustment members28a user can determine settings for a particular patient and make precise adjustments to each adjustment member28to precisely position the head ring12, e.g., to avoid certain features of the patient's head, to rotate the head ring properly, etc. It is to be appreciated that the adjustment members28may have one or more measurement system disposed on one surface. For example, on one side of the surface of the adjustment member28may display an inch scale32while the other side may display a centimeter scale34. Other measurement scales and systems are contemplated.

In the embodiment shown, the support member26is generally triangular but other configurations are contemplated. In this embodiment, the support member26has three corners36with the adjustment members28fixed at each of the corners36. In this manner, the weight of the head ring14is equally distributed and is stable on the patient's head. Other shapes for the support member26are contemplated by the present disclosure as along as the adjustment members28are equally spaced about the periphery of the support member26for stability.

In use, the positioner10will be coupled to a head ring14and the positioner10and head ring14will be disposed on the patient's head to fix the head ring to the patient's skull.

Referring now toFIG. 4, there is shown a BRW/CRW-type stereotactic head ring14as is known in the art. The head ring14comprises an annular base38, formed of metal. Four vertical brackets40extend upward from the inside diameter of the base38. Four adjustable pins42are threadedly engaged with the upper portions of the brackets40. The pins42, when rotated relative to the brackets40, extend inwardly to engage the patient's skull, or retract outwardly to disengage from the patient's skull. The pins42have pointed tips or ends44which, when the pins are extended inwardly, penetrate the outer tissue of the patient's head and engage the bone of the skull so as to rigidly and invasively affix the head ring14to the skull. The pin tips or ends44may be removable and replaceable so as to reduce the possibility of spreading infection from one user of the head ring apparatus to the next. If reusable, the pins tips or ends44are sterilized after each patient's use.

The head ring14includes means for attaching to it other appliances used in stereotactic procedures, e.g., a localizer. As shown, these comprise a plurality, ordinarily three, of recessed ball sockets46into which the ball-type connectors of compatible stereotactic appliances may be received. As shown inFIG. 4, the connectors20of positioner10align with (as indicated by the arrows) and are received by the sockets46to fix the positioner to the head ring14. Spindles48extending downwardly from the underside of the head ring14are connected to internal means (not shown) in the head ring base38for locking in place ball-type connectors20received in the sockets46.

Referring toFIG. 5, the positioner10and head ring14are disposed on a patient's head50. Initially, the support member26of the positioner10comes into contact with a top potion of the patient's head50and generally supports the head ring14about the patient's head in a stable manner. The user, e.g., neurosurgeon, can then adjust the position of the head ring14and corresponding pin tips or ends44relative to the patient's head by adjusting the adjustment members28. For example, when the adjustment members28include hook and loop fasteners, the user can separate an end52that has passed through the bracket30from the remaining portion54, adjust the adjustment member28accordingly and then reposition the end52back onto the other portion54of the adjustment member28. Once the head ring14has been set, the pins42are adjusted to fix the head ring14to the patient's head50.

The position of the positioner can then be determined by reading the indicia31on the adjustment members28. It is to be appreciated that each of the adjustment members may be adjusted to a different position and thus have a different measurement reading. Once the user is satisfied with the placement of the head ring14, the positioner10can be removed from the head ring14by loosening the spindles48of the head ring14. It is to be further appreciated that the positioner10of the present disclosure holds the head ring14in a steady manner during the positioning process enabling the neurosurgeon to adjust the head ring14easily and precisely in any direction.

The stereotactic head ring14may be employed to support a localizing device used for establishing a coordinate system and measurement reference for diagnostic procedures and radiation treatment setup. An exemplary localizing device is described in U.S. Pat. No. 5,628,315, the contents of which are incorporated by reference. When diagnostic scanning procedures such as magnetic resonance imagining (“MRI”) or computerized axial tomography (“CAT scan”) or the like are performed on a patient's head with the localizing device in place, the localizing device provides fixed indicia (fiducials) against which measurements can be made and relative to which a coordinate system can be established for the cranium and intracranial areas. In conjunction with existing computer software developed for the system, the diagnostic images produced from the CAT scan, MRI, etc., performed with the localizing device in place will provide X, Y and Z coordinates (or, in some applications, polar coordinates) for any portion of the patient's skull, brain or other tissue within the cranium which is to be investigated or treated. Such systems make it possible, for example, to identify the location of a tumor, or the like, within the patient's brain by X, Y and Z coordinates which define the position of the tumor, as well as its points of greatest extension within the brain tissue, etc. Since the localizing device is rigidly attached to the head ring14, which in turn is rigidly attached to the patient's skull50, the coordinates of diagnostic measurements made utilizing the localizing device may be used directly as coordinates for later surgical, or other treatment, procedures performed utilizing other appliances or instruments rigidly attached to the head ring14as long as the head ring remains attached in position to the patient's head.

Once the head ring has been secured to the patient, a localizer is then secured to the head ring before a patient is placed in the diagnostic or radiation machine. An exemplary radiation machine is described in U.S. Patent Application Publication No. U.S. 2007/0032795, the contents of which are hereby incorporated by reference. FIG. 1 from U.S. 2007/0032795 has been reproduced here asFIG. 6. Referring now to the drawings,FIG. 6illustrates a radiation therapy machine60suitable for use with the present invention. The radiation therapy machine60preferably includes a radiotranslucent couch or treatment table62having a cantilevered top64. The couch top62is received within a bore66of an annular housing68of the radiation therapy machine60with movement of the couch62along tracks70extending along a longitudinal axis translation. The couch62is preferably disposed along the longitudinal axis and may slide along that axis through the bore66passing first the front surface and then the rear surface. The couch62is supported along guide tracks70and moved by a motorized drive, such as is well known in the art, so that its position may be controlled by a computer72. A rotating gantry, coaxial with the bore66and positioned within the housing68, supports an x-ray source and a high energy radiation source on its inner surface.

Conventionally, a plastic block or blocks have been used to support the patient's head with the stereotactic head frame on the couch or treatment table62. However, the blocks allow the patient's head to move and thus the head frame which may cause misalignment with the coordinate systems. Furthermore, the conventional configuration with the blocks puts a great deal of pressure on for example a plastic CT localizer box. The plastic CT localizer box acts as a weight support for the patient's head. It is foreseeable that repeated pressure on the plastic CT localizer box will ultimately compromise the CT localizer box's integrity. To overcome these deficiencies, a tabletop adapter74is provided to fix the head ring on the patient's head to the CT or treatment table62which will prevent movement by the patient and relieve unnecessary pressure on the localizing device.

Referring toFIGS. 6-10, the adapter74includes a generally, flat rectangular substrate76configured to be disposed on a treatment table62and to support the patient on the treatment table62. The substrate76has a top surface78and a bottom surface80. At least two connectors82are disposed on and project from the bottom surface80of the substrate76. The at least two connectors82are adapted to couple the substrate76to recesses84formed along the sides of the treatment table62. The adapter76further includes a U-shaped bracket86disposed on one end of the substrate76having at least two receiving members88,90projecting perpendicular from the top surface78of the substrate76. The at least two receiving members88,90, e.g., semi-circular apertures, are configured for receiving screws of the head frame14for fixing the head frame14relative to the treatment table62, as shown inFIGS. 9 and 10.

Referring toFIGS. 9 and 10, the adapter76has been fixed to the treatment table62by coupling the connectors82into the recesses84of the table62. For clarity, the head ring14with localizing device94is shown without being fixed to a patient's head. The two conical T-bolt screws92are aligned with the receiving members88,90of the bracket86. Once the screws92are fully received by the receiving members88,90, the screws92are clamped down and the head ring14is fixed to the adapter76, and in turn, the head ring14is fixed to the treatment couch or table62. By securing the head ring to the treatment table62in this manner, the adapter76eliminates any potential patient head movement during treatment, e.g., a CT simulation or radiotherapy treatment. Furthermore, the adapter76reduces any additional pressure on the localizing device.

Once the patient is set on the couch or table62, the patient can be positioned into the bore66of the radiation machine60.