Unitary multilumen cranial bolt

Abstract

A unitary multilumen cranial bolt for use in multimodal monitoring of a plurality of physiological parameters in brain tissue incorporates a plurality of lumens, each lumen directing a catheter borne sensor through a bore hole in the cranium and into brain tissue of a patient. The lumens are configured to cause the catheters to splay outward as they enter the cranial cavity and reach their intended depth of penetration. Each lumen is associated with a guide. The guides are adapted for use with introducers that enable fragile and/or flexible sensors to be introduced into brain tissue. Each catheter borne sensor can be positioned and repositioned within brain tissue independently of all other sensors.

1 . A device for providing access to the cranial cavity of a patient comprising:
 a unitary body having a proximal end and a distal end and forming a plurality of lumens therethrough extending between said proximal and distal ends, said distal end of said unitary body forming a threaded shank for engaging the wall of a burr hole through the cranium of a patient;   wherein the locations of said lumens at said distal end are angularly displaced about the axis of rotation of said shank with respect to the locations of said lumens at said proximal end so that said lumens are skewed relative to the axis of rotation of said shank, said lumens converging from a relatively disparate locations in the proximal end of said unitary body to relatively close proximity in said shank without intersecting, each lumen having a proximal end situated outside the cranial wall when the device is in use and a distal end accessing the interior of the cranial wall when the device is in use.   
     
     
         2 . The device according to  claim 1  wherein the angular displacements are such that each lumen intersects in said unitary body the path that an adjacent lumen would take if the distal end of the adjacent lumen were not angularly displaced with respect to its proximal end. 
     
     
         3 . The device according to  claim 1  wherein the angular displacement of the distal ends of said lumens relative to the proximal ends of said lumens about the axis of rotation of said shank is approximately 75°. 
     
     
         4 . The device according to  claim 1  further comprising one or more tubular guides connected to one or more of said lumens at their proximal ends for conducting a catheter to said lumen. 
     
     
         5 . The device according to  claim 4  wherein each said tubular guide is flexible further comprising a connector for mounting each said flexible guide to one of said lumens, each said connector having an expanded zone for engaging and holding in place a flexible guide. 
     
     
         6 . The device according to  claim 4  further comprising a tubular introducer adapted to be inserted through a tubular guide and its associated lumen for introducing a delicate catheter borne sensor through said guide and lumen into the interior of the cranial wall. 
     
     
         7 . The device according to  claim 6  further comprising a stylet within said introducer for stiffening said introducer during installation of said introducer through a tubular guide and its associated lumen. 
     
     
         8 . The device according to  claim 7  wherein the distal end of said stylet includes means for opening the Dura to provide access to brain tissue. 
     
     
         9 . The device according to  claim 6  wherein the distal end of said introducer includes means for opening the dura to provide access to brain tissue. 
     
     
         10 . The device according to  claim 1  wherein the close proximity of said lumens within said threaded shank defines a nadir of convergence of said lumens in said shank, the separation of each one of said lumens from adjacent lumens in the nadir of convergence being not more than the diameter of the larger of said one and said adjacent lumens and not substantially less than 0.009 inch. 
     
     
         11 . The device according to  claim 1  wherein the close proximity of said lumens within said threaded shank defines a nadir of convergence of said lumens in said shank, the separation of each one of said lumens from adjacent lumens in the nadir of convergence being approximately 0.01 inch. 
     
     
         12 . A bolt for providing access to the cranial cavity of a patient comprising a solid, unitary body having a proximal end and a distal end, a threaded shank at the distal end and at least three but not more than five lumens traversing the length of said body between the proximal end and the distal end, the distal ends of said lumens being angularly displaced with respect to the proximal ends of said lumens, said lumens at their proximal ends being located radially outward from the axis of rotation of said threaded shank and converging from the outward locations toward each other and toward the axis of rotation of said threaded shank for causing said lumens to be nested compactly together about the axis of rotation without intersecting. 
     
     
         13 . A device according to  claim 12  wherein said lumens define divergent paths from their distal ends. 
     
     
         14 . A system for providing access into the cranial cavity of a patient for a catheter borne sensor comprising:
 a unitary body having a proximal end and a distal end;   a threaded shank at the distal end of said unitary body for engaging the wall of a burr hole through the cranium of a patient;   a plurality of lumens formed through the unitary body at skewed angles with respect to the axis of rotation of said shank and converging from disparate locations in the proximal end of said unitary body toward each other to define a nadir of convergence in said shank, each lumen having a proximal end situated outside the cranial wall when the device is in use and a distal end accessing the interior of the cranial wall when the device is in use; and   one or more tubular guides attachable to said unitary body at the proximal end of one or more of said lumens for guiding a catheter from the exterior of the cranial cavity to the interior thereof.   
     
     
         15 . The system according to  claim 14  wherein four lumens formed within said unitary body further comprising four of said tubular guides, one attached to the proximal end of each lumen. 
     
     
         16 . The system according to  claim 14  further comprising at least one tubular introducer adapted to pass through a guide and its associated lumen for introducing to the cranial cavity a flexible or delicate catheter borne sensor. 
     
     
         17 . The system according to  claim 16  further comprising means at the distal end of said introducer for opening the dura when inside the cranial cavity to allow access to brain tissue for a catheter mounted sensor. 
     
     
         18 . The system according to  claim 14  wherein said skewed angles are such that each lumen intersects the path that an adjacent lumen would take if such adjacent lumen were not skewed with respect to said axis of rotation. 
     
     
         19 . The system according to  claim 14  wherein the proximity at said nadir of convergence of each one of said lumens to an adjacent lumen is not more than the diameter of the smaller of said one lumen and said adjacent lumen and not substantially less than 0.009 inch. 
     
     
         20 . The system according to  claim 14  wherein the proximity of each one of said lumens to an adjacent lumen at said nadir of convergence is approximately 0.01 inch. 
     
     
         21 . The system according to  claim 14  wherein said lumens define a nadir of convergence at the distal end of said shank. 
     
     
         22 . A system for providing access into the cranial cavity of a patient for a catheter borne sensor comprising:
 a unitary body having a proximal end and a distal end;   a threaded shank at the distal end of said unitary body for engaging the wall of a burr hole through the cranium of a patient;   a plurality of lumens extending through the unitary body without intersecting, each lumen having a proximal end situated outside the cranial wall when the device is in use and a distal end accessing the interior of the cranial wall when the device is in use;   a tubular guide attached to said unitary body at the proximal end of each of said lumens for guiding a catheter borne sensor from the exterior of the cranial cavity to the proximal end of each said lumen; and   at least one tubular introducer adapted to pass through a tubular guide and its associated lumen for introducing into the cranial cavity a flexible or delicate catheter borne sensor.   
     
     
         23 . The system according to  claim 22  wherein four lumens extend through said unitary body further comprising four of said tubular guides, one attached to the proximal end of each lumen. 
     
     
         24 . The system according to  claim 22  further comprising means on one or more of said tubular guides for releasably fixing in place a catheter borne sensor introduced into the cranial cavity through said tubular guide, each one of said fixing means being operable independently of other fixing means to fix in place and release the catheter borne sensor introduced through the tubular guide associated with said one fixing means for positioning and repositioning one of the catheter borne sensors independently of other catheter borne sensors.