Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/45—For evaluating or diagnosing the musculoskeletal system or teeth
  • A61B5/4514—Cartilage
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/103—Measuring devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
  • A61B5/107—Measuring physical dimensions, e.g. size of the entire body or parts thereof
  • A61B5/1076—Measuring physical dimensions, e.g. size of the entire body or parts thereof for measuring dimensions inside body cavities, e.g. using catheters
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B90/00—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
  • A61B90/06—Measuring instruments not otherwise provided for
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F17/00—Methods or apparatus for determining the capacity of containers or cavities, or the volume of solid bodies
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/00234—Surgical instruments, devices or methods for minimally invasive surgery
  • A61B2017/00238—Type of minimally invasive operation
  • A61B2017/00261—Discectomy
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B90/00—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
  • A61B90/39—Markers, e.g. radio-opaque or breast lesions markers
  • A61B2090/3933—Liquid markers

Definitions

• This invention relates to intervertebral discs. More particularly, it relates to a method and apparatus for determining the amount of nuclear material removed from said disc during, and the shapes of the cavity created after lumbar surgery.
• the normal intervertebral disc has an outer ligamentous ring called the annulus which binds the adjacent vertebrae together and is constituted of collagen fibers that are attached to the vertebrae and cross each other so that half of the individual fibers will tighten as the vertebrae are rotated in either direction, thus resisting twisting or torsional motion. Torsional movement between vertebral segments is further restricted by the facet joints.
• a classical disc herniation occurs when the annular fibers are weakened or torn and the inner tissue of the nucleus becomes permanently bulged, distended, or extruded out of its normal annular confines. Leg pain in such case results from this nuclear tissue (or an intact weakened, bulging annulus) compressing a nerve which passes outward from the spinal canal to the leg.
• nucleus material is removed.
• the major purpose of removing the nucleus material is decompression - i.e., relief of the compression of the nerve caused, directly or indirectly, by the nucleus.
• There are many surgical techniques used to remove nucleus material such as open surgery, Microdiscectomy (e.g., Arthroscopic MicroDiscectomy), serdiscectomy and Automated Percutaneous Lumbar Discectomy. Since the amount of removed nucleus can directly affect the intradiscal pressure of the disc and the overall results of the discectomy surgery, it is desirable to know how much nucleus has been removed from the disc during the discectomy.
• Capanna et al. (Spine. 6, 610-614 [1981]) described a method for measuring the "percentage of disc removal" during lumbar discectomy using discograms and lumbosacral radiographs.
• this method does not provide a simple way to give the volume and is unable to define the shape of the cavity. Furthermore, it is subject to relatively large errors.
• Another way of measuring the nucleus of the material weight is to install a filter in the suction tube, separate the nucleus material from the flushing solution and then weigh the nucleus material.
• the nucleus material tends to absorb fluids resulting in a weight change after it has been removed from the disc. This method does not give an accurate measurement.
• Another object of the invention is to provide an apparatus for use in determining the amount of nuclear material removed from a disc during a discectomy which comprises a flexible expandable first container, a liquid and a calibrated container for said liquid in fluid connection with said first container.
• Yet another object of the invention is to provide an apparatus, as described above, wherein said calibrated container comprises syringe means comprising a hollow tube, comprising an opening at each and thereof, to contain said liquid and means to cause the liquid contained in the tube to be injected into the second container means.
• said calibrated container comprises syringe means comprising a hollow tube, comprising an opening at each and thereof, to contain said liquid and means to cause the liquid contained in the tube to be injected into the second container means.
• Another object of the invention is to provide an apparatus, as described above, wherein said filling means comprises a flexible, collapsible bulb which is caused to collapse by the application of pressure applied to the outer walls thereof wherein the liquid, contained in said tube is injected into the first container to which it is fluidly connected, and causes the first container to expand.
• said filling means comprises a flexible, collapsible bulb which is caused to collapse by the application of pressure applied to the outer walls thereof wherein the liquid, contained in said tube is injected into the first container to which it is fluidly connected, and causes the first container to expand.
• said filling means comprises a syringe, comprising a calibrated barrel and an axially and reciprocally movable plunger inserted therein or the combination of a pipette with means to cause liquid contained therein to be expelled therefrom.
• Another object of the invention is to provide an apparatus, as described above, wherein said means to cause the liquid to be expelled from the pipette comprises a flexible, collapible bulb.
• Yet another object of the invention is to provide an apparatus for use in determining the shape of the cavity in a disc after removal of nuclear material therefrom comprising a flexible expandable first container, a liquid and a calibrated second container for said liquid in fluid connection with said flexible expandable container wherein said liquid contains a composition which allows the shape of the container holding said liquid to become visible in an imaging apparatus.
• a flexible expandable first container a liquid and a calibrated second container for said liquid in fluid connection with said flexible expandable container wherein said liquid contains a composition which allows the shape of the container holding said liquid to become visible in an imaging apparatus.
• Figures 1 B-1 D are sectional views showing various positions of the bore of the valve means of the apparatus of Figure 1A.
• Figure 2 is a top plan view of an intervertebral disc with its nuclear material removed and a hole through one wall of its annulus.
• Figure 3 is an elevational sectional view of the disc of Figure 2.
• Figure 4 is an elevational sectional view of the apparatus of Figure 1 A set up for calibration.
• Figure 5 is an elevational sectional view of the apparatus of Figure 1A set up for measurement of the volume of the nuclear cavity of an intervertebral disc. DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
• the apparatus of the invention designated by the numeral 1 , comprises a calibrated second container 10 comprising an opening 12 at one end and an outlet stem 11 at the other end.
• Container 10 further comprises injection means to cause the liquid to flow from said container when pressure is applied to said injection means.
• Outlet stem 11 comprises a distal portion 11a adjacent the barrel of the container and a proximal portion 11 b separated from the distal portion by valve means 20.
• the valve means may be 2- or 3- way valves.
• the outlet stem portion and valve may be unitary (as shown) or comprise two or more parts joined by connecting means.
• the upper, open portion of a flexible, expandable first container 31 (a balloon in the illustration) is stretched and draped over the flange 35 of an outer tube 34.
• An inner tube 33 is inserted into the mouth of the balloon 31 until its proximal end passes the distal opening in outer tube 34.
• the outer diameter of the inner tube 33 and inner diameter of the outer tube 34 are so selected that the wall of balloon 31 is held tightly between them.
• Flange 35 may be an integral part of tube 34 or may comprise a separate ring axially movable along the outer wall of tube 34.
• Inner tube 33 is fluidly connected to valve means 20 through connecting tube 13 which is attached to the distal end of inner tube 33 and the outlet stem portion 11b.
• a disc the volume of whose nuclear cavity is to be determined by the method of the invention, is illustrated in Figures 2 and 3 and designated by the numeral 40.
• the disc comprises a fibrous annulus 41 and a cavity 42 from which the nucleus material has been removed in the surgeon's usual manner, e.g., curettage and microdiscectomy with pituitary forceps.
• the disc further comprises a longitudinal hole 43, extending from the outer wall 37 to the cavity, through which the nuclear material has been removed.
• the volume of the apparatus between valve means 20 and the proximal end of outer tube 34 is determined as follows.
• the initial volume of liquid L in container 10 is obtained from the marking a thereon.
• the bore 22 of valve means 20 is turned to the position shown in Figure 1 B and vacuum applied through stem 21 whereby balloon 31 is evacuated and collapses.
• the bore 22 of the valve means is then turned to the position shown in Figure 1 D and liquid L is allowed to flow from container 10 through bore 22 and connecting tubes 13 and 33 into first container 31.
• Container 31 expands, filling the cavity in outer tube 34 until the proximal end 39 of the expanded balloon is flush with the proximal opening 44 of outer tube 34.
• a reading, b is taken of the volume of liquid L in container 1.
• the difference between a and b is the volume of the measuring apparatus between valve means 20 and the proximal end 39 of expanded balloon 31.
• the outer tube 34 of the apparatus 1 is then inserted into hole 43 of the disc 40 until the inner surface 36 of flange 35 of the outer tube abuts the outer wall 37 of the disc.
• the length of outer tube 34 is so chosen that it does not extend into the cavity 42 formed upon removal of the nuclear material from the disc. Liquid L is allowed to continue to flow until the expanded balloon fills the cavity 42 of the disc. A reading is then taken of the volume c in container 1. The difference between b and c is the volume of the cavity 42 in the disc.
• the filling means comprises a) rigid second container means, to contain the liquid, which comprise a barrel comprising open proximal and distal ends; b) pressure means, at the proximal end of the barrel, to apply pressure to the liquid and force it to flow out of the barrel at the distal end thereof.
• Filling means for use in the practice of this invention include syringes wherein a) the second container means comprises a pipette (e.g., catalog number 13-678, Fisher Scientific, Pittsburgh, PA 15219) and the pressure means comprises a bulbs or dispensers (e.g., catalog numbers 13-681-15, 13-681-50, 13-681-61 and 14- 070, ibid).
• a pipette e.g., catalog number 13-678, Fisher Scientific, Pittsburgh, PA 15219
• the pressure means comprises a bulbs or dispensers (e.g., catalog numbers 13-681-15, 13-681-50, 13-681-61 and 14- 070, ibid).
• the second container means comprises a cylindrical barrel, disposed about a longitudinal axis and the pressure means comprises plunger means, which is inserted through the proximal opening of the barrel, and is axially and reciprocally movable therein (such a combination is, e.g., a syringe such as catalog number 14-823- 10, ibid).
• Preferred filling means are syringes (such as catalog number 13-578, above) of about 5 to about 10 ml capacity.
• the materials of construction for use in the invention are biocompatible materials such as plastics and metals.
• the materials of construction must also be compatible with the measuring liquids.
• the first container may be made from any physiologically compatible elastic material such as natural, synthetic, silicone or polyurethane rubbers.
• Liquids, L for use in the practice of the invention include water and aqueous solutions of pharmaceutically acceptable salts (e.g., saline).
• pharmaceutically acceptable salts e.g., saline
• the liquid L comprises a contrasting composition which causes the cavity to become visible in an imaging device.
• indicating compositions include both oil-based and water-based media such as iophendylate, meglumine iothalamate, diatriazoate meglumine and Renogatrin (trademark) mixed with methylene blue. Water-based compositions are preferred.
• imaging devices include computed tomography (CT) scanners and magnetic resonance imaging (MRI).
• CT computed tomography
• MRI magnetic resonance imaging
• the apparatus can be calibrated as follows: Outer tube 34, of the apparatus is inserted into a receiving container, designated 2 and shown in Fig. 4, until a marking thereon indicating a known volume V. The initial volume a in container 1 is recorded. Valve 20 is turned so that the bore thereof is in the position shown in Figure 1 B. Vacuum is applied to the apparatus, from a vacuum source (not shown), through stem 21 of the valve, whereby the balloon 31 is evacuated and deflated.
• valve 20 The bore 22 of valve 20 is then turned until it assumes the position shown in Figure 1 D at which time the liquid L flows from container 1 into the balloon through the valve and connecting tubes 13 and 33. As the balloon fills with the liquid it expands until it fills the whole empty space of the receiver 2.
• the volume of the apparatus, V A without the receiver, is then:
• V A V T - V.
• the volume of the apparatus must then be recalculated to take into consideration any differences in volume caused by a change in the tube's length.
• the new volume V' A of the apparatus is given by wherein D is the inner diameter of outer tube 34 and I, which may be positive or negative is the change in length of the outer tube.
• the receiver 2 is then removed from the outer tube 34 and the balloon drained and deflated through valve stem 21 of valve 20. Outer tube 34 with its associated balloon 31 and inner tube 33 are then inserted into the disc 40 through hole 43, as described above.
• Container 10 is filled with liquid L until the level a and the volume corresponding to that level is recorded Valve 20 is opened to the position shown in Fig. 1 D and the liquid flows into the balloon causing it to expand and fill cavity 42 of disc 40. The volume of liquid in container 10 drops to the level c and the volume corresponding thereto is recorded.
• the volume V' ⁇ of the apparatus and cavity from volume 21 is given by b - c.
• the volume of the disc is then given by V' ⁇ - V' A wherein V' A is determined as above.
• the measuring device consists of a 10 ml syringe (Reorder number 9604, Becton-Dickinson, Rutherford, NJ 07070) comprising a male Luer fitting at its distal end, a bidirectional stopcock (Catalog number G-06464-72, Cole-Palmer, Niles, IL 60714), a polypropylene extension tube and a small balloon.
• the bidirectional stopcock has a female Luer fitting at one end and a male Luer fitting at the other end. The female Luer fitting of the stopcock was connected to the syringe through its male Luer end.
• the extension tube was about 20 mm long, had an inner diameter of about 5 mm, an outer diameter of about 6 mm and a female Luer fitting at one end.
• the small balloon was inserted into the extension tube with the closed end of the balloon going into the Luer fitting side leaving some of the balloon outside of the tube.
• the open end of the balloon was then stretched and draped over the outside of the tube.
• the male Luer end of the stopcock was carefully inserted into the female Luer end of the extension tube with the balloon sitting inside of the tube until the tube is securely locked into the stopcock.
• the stopcock was turned to its open position and the plunger of the syringe was slowly drawn back to create a vacuum in the system. While the system was still under vacuum the stopcock was turned to the off position.
• the exact volume of the cavity was measured by first weighing the empty plastic block and then weighing the block with the nucleus shaped cavity filed with water (not to the cylindrical window). The difference between these two weights was 4.2 gm. Since the density of water is 1 , the volume of the cavity is 4.2 cc.
• the extension tube of the device of Part A was inserted into the cylindrical window and the tip of the tube was aligned with the end of the window.
• the initial volume of saline in the syringe, before opening the stopcock, was 9.2 cc. After opening the stopcock, the saline was injected into the balloon.
• the balloon expanded until the whole volume of the cavity was filled with the inflated balloon. At this point, it was almost impossible to inject more saline into the balloon.
• the volume of saline in the syringe was again determined and found to be 4.8 cc. The difference between the initial and final readings is the volume injected (4.4 cc). Since the volume of the cavity is 4.2 cc. Therefore, the device had a dead volume of about 0.2 cc which should be subtracted from the volume of liquid dispensed by the syringe in determining nucleus cavity volumes.
• a discectomy was performed on a cadaveric lumbar disc using a pituitary rongeur.
• the nucleus materials which were removed during discectomy were carefuly collected and weighed. The weight of the removed nucleus material was found to be
• the volumes of the excavated cavities of other cadaveric discs were determined by the above method. It was found that the directly measured volumes did not differ from the weights of the excavated nucleus materials by significant amounts. Generally the difference was less than about 0.2 cc. This accuracy is much better than any other methods and is good enough for most purposes.

Landscapes

• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Surgery (AREA)
• General Health & Medical Sciences (AREA)
• Veterinary Medicine (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Engineering & Computer Science (AREA)
• Biomedical Technology (AREA)
• Heart & Thoracic Surgery (AREA)
• Medical Informatics (AREA)
• Molecular Biology (AREA)
• Animal Behavior & Ethology (AREA)
• Physics & Mathematics (AREA)
• Public Health (AREA)
• Pathology (AREA)
• Dentistry (AREA)
• Biophysics (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Fluid Mechanics (AREA)
• General Physics & Mathematics (AREA)
• Orthopedic Medicine & Surgery (AREA)
• Rheumatology (AREA)
• Prostheses (AREA)
• Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
• Surgical Instruments (AREA)
• Instructional Devices (AREA)
• Apparatus For Radiation Diagnosis (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=22827266

Family Applications (1)

Country Status (4)

Families Citing this family (10)

Family Cites Families (2)

• 1995
  • 1995-01-19 EP EP95904685A patent/EP0752832A1/de not_active Withdrawn
  • 1995-01-19 JP JP7525535A patent/JP2865427B2/ja not_active Expired - Fee Related
  • 1995-01-19 CA CA002185919A patent/CA2185919C/en not_active Expired - Fee Related
  • 1995-01-19 WO PCT/IB1995/000042 patent/WO1995026689A1/en not_active Ceased

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events