.
`
`Unltfid States Patent
`Jacobson
`
`[19]
`
`[11] Patent Number:
`[45] Date of Patent:
`
`4,545,374
`Oct. 8, 1985
`
`OTHER PUBLICATIONS
`“Nucleography", May 1952, issue of Journal of Bone
`find -'°"“ 5‘“ge’Y_- V°1- 345v N°- 2-
`,
`Dr. Parvas Kanbin Develops New Surgical Procedure
`Aiding Herniated Spinal Disk Sufferers”, May 1982,
`ssue of
`Ima
`
`v 1.ge, o 6, N
`o. 5.
`i
`ta
`.
`t
`;1‘Microl;r§1bz:f;ll)D]1iscec_tomy”, Feb. 1982, issue of Resi-
`..3'h";'}y Aching
`P. D,’ Saturday] Nov. 7, 1981’
`‘me °f The Miami H°”‘1d'
`;3PeIi;iiot::::us Lumbar Discectomy“. 1981, Dr. Robert
`'
`'
`Primaiy Examt'ner—C. Fred Rosenbaum
`Assistant Examiner-—Gene B. Kartchner
`
`Attorney, Agent, or Firm—Pennie & Edmonds
`[571
`ABSTRACT
`A method for percutaneously accessing the lumbar
`region of the spinal column by laterally inserting a can-
`nula through the patient’s side above the pelvic crest to
`Contact a predetermined position in the lumbar region
`and passing objects
`such as medical
`instruments
`-
`-
`_
`through the cannlila. 'l1)‘h1sdr_n1e(tl1:>d is usgful for perform
`ing percu aneous um ar
`is ec omies ycuttingapor-
`t e cannuaan removing a esire amount 0 nuc eus
`tLon of the patent s disc cagdsule zgid nucleusfthropgh
`material. The cannula has a tubular member and anchor
`
`means attached to one end of the member for anchoring
`«
`-
`h
`-
`_
`the cannula in ‘body US$116’ to prevent
`caring move
`men! between it and the tissue. Other instruments for
`,
`.
`d.
`performing a percutaneous lumbar diskectomy are is-
`closed, including a speculum and trocar for percutane-
`ously inserting the cannula into the patient’s body, a
`diskectomy knife for cutting disc nucleus material and
`rongeur forceps for removing the disc material. The
`above instruments may be combined in a surgical appa-
`rams-
`
`32 Claims, 22 Drawing Figures
`
`[54] METHOD AND INSTRUMENTS FOR
`PERFORMING A PERCUTANEOUS
`LUMBAR DISKECIOMY
`Inventor: Robert E. Jacobson, 1295 NW. 14:11
`St” Suite G! Miami, Fla_ 33125
`1211 Appl- No-: 414,779
`
`[76]
`
`Sep. 3, 1982
`
`[22] Filed:
`................ A6113 17/on
`[51]
`Int. Cl.‘ ....
`23 312 128/34311286/ti?/aigni 162084//3:?65zi
`[52] us‘ CL
`[58] Field of seimh/fl
`’
`" 128'/3’48_1’ 92 E’ 92 EB’
`
`128/303 R,
`-754, 341-343, 345, 3, 126,
`305.3, 741, 303.11, 303.13, 783-784, 362;
`604/22, 164-166, 264, 904
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`29917787 7/1%] Sh Id
`1_
`. 123/305.3
`
`6 E" et 8
`3,303,319
`3/1957
`504/[64
`3,320,131 5/1967
`~~~~~ 123/17
`3,320,948 5/1967
`3~334«087 5/‘968 B"“"""°”‘amP '
`' 128/3053
`3,388,703 6/I968 Bowes
`604/I66
`3,459,189 8/I969 Alley at 3 _
`604/166
`3,511,243 5/I970 Toy _____W
`_ 123/305.3
`3,606,878
`9/1971 Kellogg, Jr.
`3,530,350
`9/1970 Majoms ‘
`3,612,050 10/1971 Sheridan
`
`.. 604/166
`
`.
`
`
`
`‘S3913?’ 1
`,
`,
`tan eta .
`33441274 lo/1974 Nordmom .
`3,870,048
`3/1975 Yoon .
`3313534 10/19-,5 Waichie _
`3,954,4go 5/1976 1:,-oning _
`3,995,619 12/1976 Glatzer .
`4.0431343
`3/1977 Williams -
`4v”4»5]8
`9/1973 V‘“'g"5 "
`4,273,131
`6/1981 Olsen .
`4’222‘38O 9/1980 Temyama '
`4,291,696
`9/1931 Ring ..
`4,369,768
`1/1983 Vukovic
`4,411,655 10/1983 Schreck .
`
`
`
`" 504/165
`.. 128/341
`504/904
`128/6
`604/165
`
`..
`
`
`
`NUVASIVE 1004
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`METHOD AND INSTRUMENTS FOR
`PERFORMING A PERCUTANEOUS LUMBAR
`DISKECTOMY
`
`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`The invention relates to a method and instruments to
`perform a percutaneous lumbar diskectomy.
`2. Description of the Prior Art
`Many people suffer from lower back pain in the lum-
`bar region of their spines caused by a herniated or pro-
`truding lumbar vertebral disc which is often called a
`slipped disc. Spinal discs are shock absorbing cushions
`between spinal vertebrae. FIG. 1 shows a schematic
`view of a typical disc 1 sandwiched between two verte-
`brae 2. ‘The disc has a fibrous capsule or annulus 3
`which surrounds a cartilage—like nucleus 4 that has a
`consistency similar to a raw potato. Discs are avascular,
`that is, they have no blood vessels. In a herniated or
`bulging disc, there are small tears in the disc capsule
`which allow the nucleus material to bulge and expand
`around the tear. If the bulge contacts spinal nerves, the
`person may experience extreme shooting pain in his
`back or legs.
`'
`A slipped disc is treated by eliminating nerve contact.
`It has been found that bed rest and spinal traction may
`alleviate the pain in simple cases. In more serious cases,
`a portion of the affected disc nucleus has been surgically
`removed, which relieves the disc bulge, in a procedure
`known as a laminectomy.
`Since the disc is confined within the spinal column, it
`must be accessed in order to remove nucleus material.
`In a laminectomy, nucleus access is obtained by cutting
`a channel from the rear of the patient’s back through the
`vertebral lamina to the disc. A long incision of the order
`of six inches is made through the skin and fat layer to
`the lamina. The incision eventually heals as an unattrac-
`tive scar. The surgeon cuts through the lamina and
`retracts body tissue including spinal nerves and blood
`vessels located around the dural sac 5 (a conduit for the
`nerves),
`ligaments and major back support muscles.
`Once the channel is cleared, the surgeon cuts a hole into
`the disc capsule through which he passes instruments in
`order to remove a portion of the disc nucleus. The
`procedure is normally performed in about one and one-
`half hours, while the patient is under general anesthesia.
`In known laminectomy procedures, the surgeon does
`not visually inspect the nucleus removal because he is
`removing the material by feel. Since instruments are
`blindly inserted through the hole, very occasionally
`they overpenetrate through the other side of the disc
`and damage other tissue structure.
`A laminectomy is a very destructive process. Cutting
`laruina and retracting spinal nerves, blood vessels, mus-
`cle and ligaments often leads to permanent scarring
`which may cause more permanent pain than the original
`slipped disc. Many people prefer to continue suffering
`pain caused by the herniated disc rather than risk per-
`manent pain from the laminectomy. Laminectomies also
`require long hospitalization and hence postoperative
`recovery periods, typically from one to two months, if
`there have been no complications caused by the opera-
`tion.
`In the past, other procedures have been developed in
`order to alleviate disc herniation. One procedure was to
`inject a nucleus dissolving chymopapain enzyme into
`the disc with a spinal needle to relieve the pressure on
`
`10
`
`15
`
`25
`
`30
`
`35
`
`40
`
`55
`
`60
`
`2
`the nerves. The United States Food and Drug Adminis-
`tration banned the use of chymopapain enzyme for this
`procedure in the mid-1970's. Clinical
`testing raised
`doubts concerning its effectiveness and its significant
`complications due to tissue reaction to the enzyme.
`Another known procedure is a microsurgical diskec-
`tomy. As in a laminectomy, the disc is accessed by
`cutting a channel from the rear of the patient’s back to
`the disc. However, by using a smaller incision and vi-
`sual magnification with an operating microscope or
`operating loupes, small diameter microsurgical instru-
`ments can pass between the vertebral laminae without
`bone cutting and into the disc. Blood vessels and nerves
`are still retracted. Scarring and post operative pain is
`reduced, but not eliminated.
`There has thus been a long felt need in the medical
`profession to reduce the cost, risk, pain, and recovery
`time of diskectomies. All of these drawbacks are materi-
`ally reduced by performance of a percutaneous lumbar
`diskectomy disclosed herein.
`SUMMARY OF THE INVENTION
`
`The method according to the teaching of the present
`invention percutaneously accesses a the lumbar region
`of a patient’s spinal column by laterally inserting a can-
`nula through the patient’s side above the pelvic crest to
`contact a predetermined position in the lumbar region
`and conducting a surgical procedure on the spinal col-
`umn by manipulating instruments through the cannula.
`The lateral approach does not intersect bone, nerves,
`blood vessels, major back support muscles or ligaments
`which would otherwise have to be cut or retracted.
`The above method is used to perform a percutaneous
`lumbar diskectomy procedure to access an injured spi-
`nal disc. The cannula is passed from just above the
`pelvic crest to a position where the cannula‘s open end
`contacts the injured disc. Then it is anchored to the
`disc. The cannula defines a percutaneous channel from
`outside the body to the disc. By passing specially de-
`signed instruments through the anchored cannula, the
`surgeon pierces the disc annulus and removes a portion
`of the nucleus in order to relieve disc bulging. Once the
`desired amount of nucleus is removed, the cannula is
`removed. The entire procedure is preferably monitored
`under fluoroscopic X-ray to insure proper cannula
`placement and manuvering of
`instruments
`there-
`through.
`A percutaneous lumbar diskectomy performed in
`accordance with the teachings of the present invention
`is not performed through the patient’s back. There is no
`need to cut spinal laminae or to retract nerves, blood
`vessels, muscles or ligaments. Instruments constructed
`in accordance with the invention allow the procedure
`to be performed in approximately 15 minutes under
`only local anesthesia. By elimination of bone cutting
`and nerve retraction, the patient experiences no scar
`induced post-operative pain. Typically, the patient will
`completely convalesce within one to two days. Some
`patients are able to walk within hours after the proce-
`dure and may be released from the hospital on the same
`day.
`Instruments constructed in accordance with the in-
`vention include a speculum, a trocar and a cannula,
`which create the percutaneous channel; a knife and
`rongeur forceps are passed down the cannula to remove
`the nucleus material.
`
`9
`
`

`
`3
`The speculum is of the type having pivotally con-
`nected handles and semi-sharp blades; it is improved by
`having guide means on at least one of the blades for
`percutaneously guiding the speculum through body
`tissue on a guide member having a diameter of less than
`approximately 3 mm. The guide means maybe a bore
`defined by at least one blade and extending approxi-
`mately parallel
`to the blade’s longest dimension for
`slidable reception of the guide member. In use, the spec-
`ulum slides along the guide member and creates a per-
`cutaneous channel along the path defined by the guide
`member.
`The cannula has anchor means attached thereto for
`anchoring it to a disc. In preferred embodiments, the
`cannula has a tubular member with an oval or elliptical
`cross section and is constructed of extruded plastic. The
`preferred anchor means are wires slidably mounted on
`the cannula tubular member.
`The trocar is inserted into the cannula and comprises
`a shaft having a tapered operating end and a tip on the
`tapered operating end for anchoring, the trocar in body
`tissue. An adjustable collar on the shaft circumferential
`surface establishes the length that the trocar is inserted
`into the cannula.
`The percutaneous lumbar diskectomy knife com-
`prises a handle, a shaft attached to the end of the handle
`having a length of approximately 200 mm and a scimi-
`tar-shaped blade attached to the shaft opposite the han-
`dle end. The blade has a convex cutting edge for cutting
`the nucleus of a spinal disc.
`The rongeur forceps is an improvement of the type
`having a pair of first and second scissor-like handles,
`pivotally connected near one end, a first shaft attached
`to the second handle at the end nearest the handle piv-
`otal connection, a second shaft pivotally connected to
`the first handle at the end nearest the handle pivotal
`connection, with the shafts abutting each other and
`forming a plane. The second shaft reciprocates relative
`to the first shaft. The forceps has first and second jaws
`having scoops; the first jaw rigidly attached to the first
`shaft, and the second jaw pivotally connected to both
`the first and second shafts for sweeping an arc about the
`first shaft pivot connection upon actuation of the han-
`dles. The jaw pivot connections are positioned so that
`the second jaw scoop is in abutting relationship with the
`first jaw scoop. The improvement comprises position-
`ing the second jaw pivot connections so that the second
`jaw sweeps an arc of approximately 90'' upon handle
`actuation. Another improved forceps attaches the jaws
`to the shafts in an intersecting relationship with the
`plane formed by the shafts.
`DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is an anterior (or front) schematic representa-
`tion of a disc and two vertebrae also showing the spinal
`nerves and blood vessels;
`FIG. 2 is a front view of the patient’s spinal column
`without nerves and blood vessels showing proper body
`positioning prior to the surgical procedure;
`FIG. 3 is a front view of the spinal column without
`nerves and blood vessels showing infiltration of local
`anesthetic in tissue around the injured disc with with a
`spinal needle;
`FIG. 4 is an enlarged front view of the injured spinal
`disc showing insertion of a speculum into the patient’s
`body to create a percutaneous channel to the disc;
`
`65
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`4,545,374
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`4
`FIG. 5 is an enlarged front view showing introduc-
`tion of the trocar and cannula into the channel created
`by the speculum;
`FIG. 6 shows the cannula anchored into the injured
`disc;
`FIG. 7 shows cutting of the disc capsule and nucleus;
`FIG. 8 shows removal of the fragmented nucleus
`with a rongeur forceps;
`FIG. 9 is a side elevational view of a speculum con-
`structed in accordance with the teachings of the present
`invention;
`FIG. 10 is an end elevational view of the speculum in
`its closed position;
`FIG. 11 is a bottom sectional view of the speculum
`taken along 11-11 of FIG. 9;
`FIG. 12 is a perspective view of a cannula;
`FIG. 13 is a sectional view of the cannula taken along
`13-13 of FIG. 12;
`FIG. 13A is a perspective view of an alternate em-
`bodiment of a cannula;
`FIG. 14 is a plan view of a trocar;
`FIG. 15 is a plan view ofthe trocar of FIG. 14 having
`a cannula inserted over it;
`FIG. 16 is a side elevational view of a diskectomy
`knife constructed in accordance with the teachings of
`the present invention;
`FIG. 16A is an enlarged view of an alternate embodi-
`ment of a diskectomy blade;
`FIG. 17 is a side elevational view of a straight ron-
`geur forceps constructed in accordance with the teach-
`ings of the present invention;
`FIG. 18 is a side elevational view of a 45° up-angled
`rongeur forceps;
`FIG. 19 is an enlarged perspective view of a Z-head
`rongeur constructed in accordance with the teachings
`of the present invention; and
`FIG. 20 is a simplified diagram showing a nerve stim-
`ulator arranged for use with a cannula and a trocar.
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`
`Method for Performing a Percutaneous Lumbar
`Diskectomy
`Referring to the drawings, FIG. 1 is a schematic view
`of a lumbar disc shown in its normal position between
`two vertebrae. This view is a front view. The patient’s
`right side would appear on the lower portion of the
`drawing and the patient’s left side on the upper portion
`of the drawing. As shown in FIG. 1, spinal nerves run
`more or less parallel to the spinal column, but some of
`them branch off in close proximity to the disc capsule.
`When the patient suffers from a “slipped disc” the
`bulging disc stretches the capsule or contacts a nerve
`that is in close proximity to the disc, and the patient
`experiences leg pain. Right leg pain means the disc is
`contacting a nerve on the right side of the spinal col-
`umn. The converse is true for left leg pain.
`In percutaneous lumbar diskectomy procedures, as in
`laminectomies, a portion of the bulging disc nucleus is
`removed to alleviate pressure on the spinal nerve. How-
`ever, if the patient has nerve contact on the left side of
`the spinal column,
`the procedure will be performed
`from the patient’s right side, while in a laminectomy or
`microlaminectomy it would be performed on the left
`side closer to the bulge. Conversely, if the patient has
`pain in the right leg, the procedure will be performed
`from the left side of his body.
`
`10
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`4,545,374
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`5
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`5
`In order to remove disc nucleus material, a cannula is
`passed laterally through the body while the patient is in
`the lateral decubitus position. Disc removal instruments
`are passed through the cannula to the disc.
`To begin the procedure, the patient 6 is placed in the
`lateral decubitus position on an operating table having a
`U-shaped convex frame 7 on the table surface, as shown
`in FIG. 2. When the patient's lumbar spinal region is
`placed on the frame, his back laterally assumes a curved
`position that stretches muscles in the area around the
`injured disc and spreads the vertebrae above and below
`the disc to allow more maneuvering room for the instru-
`ments.
`The surgeon may visually monitor the area around
`the injured disc under fluoroscopic X-ray while percu-
`taneously guiding the instruments. It is recommended
`that the surgeon wear a lead-lined apron and gloves to
`reduce his X-ray exposure. The procedure is performed
`rapidly, within about fifteen minutes, so the patient’s
`total exposure to X-rays is approximately no more than
`he would experience from a standard X-ray procedure,
`such as an upper gastrointestinal examination.
`The next step in the procedure is to anesthetize the
`patient with either general or local anesthetic. If the
`patient is locally anesthetized, the anesthetic is infil-
`trated around the chosen disc with along spinal needle.
`As shown in FIG. 3, the needle 8 is inserted laterally
`through the patient’s side above the pelvic crest and is
`percutaneously guided to position near the chosen disc
`under fluoroscopic X-ray. The spinal needle acts as a
`“go-no-go” indicator. If the needle cannot be properly
`positioned this indicates that the procedure cannot be
`used on this particular patient. Normally, the surgeon
`would then proceed with a standard laminectomy or
`microsurgical diskectomy.
`Infiltration of the anesthetic also spreads the body
`tissue around the disc, which allows easier insertion of
`the remaining surgical instruments. Once in place, the
`needle may act as a guide member or positioning ele-
`ment for instruments that create the percutaneous body
`channel. Other slender guide members that have diame-
`ters less than approximately 3 mm, such as wires, can
`also be used for positioning elements.
`After anesthetization, an approximately one centime-
`ter long skin incision is made above the pelvic crest. As
`shown in FIG. 4, a percutaneous channel 9 is then cre-
`ated through the incision to the injured disc with a
`specially designed speculum 10. The speculum 10 is
`laterally inserted through body tissue in a closed posi-
`tion, i.e., with the blades closed together. The blades
`have semi-sharp edges which spread rather than cut
`body tissue. Tissue spreading causes less bleeding and
`trauma than cutting.
`The speculum 10 may have guide means, which is
`attached to a guide member such as the anesthetization
`spinal needle. The guide means and fluoroscopic X-ray
`monitoring insures proper positioning of the speculum
`near the chosen disc.
`Once the speculum is properly positioned, the sur-
`geon spreads its jaw blades thereby creating a channel
`for cannula insertion. Other channel creating instru-
`ments such as a trocar may be used in this procedure;
`however, a speculum causes the least amount of tissue
`trauma and bleeding. A trocar can create an acceptable
`channel, but it creates unnecessary bleeding, hampering
`the surgeon because blood will tend to flow out of the
`body through the channel. Similarly, the lateral percu-
`
`6
`taneous channel may be created by a knife incision, but
`this will cause even greater bleeding.
`After creation of the body channel, the surgeon intro-
`duces a cannula 11 into the channel and then removes
`the speculum (FIGS. 5 and 6). The cannula acts as a
`conduit for insertion of surgical instruments through its
`lumen or bore, and prevents damage to surrounding
`tissue around the channel which might be caused by the
`instruments. It should be understood, however,
`that
`once inserted, the cannula may act as an instrument
`conduit for other types of surgical procedures in the
`spinal column lumbar region such as disc realignment,
`fusion, or any other surgical or diagnostic procedure.
`The cannula 11 may be constructed of metal or of any
`material compatible with general surgical sterility and
`mechanical requirements as described herein. It is pref-
`erably constructed of flexible, resilient material in order
`to accommodate minute bends or stresses caused by the
`surgeon as he manipulates instruments in the cannula.
`If the cannula is not flexible, inability to flex it will
`tend to limit the desired operating area. Cannula flexi-
`bility allows it to adjust to slight movements of the
`surgeon and tends to keep the inserted cannula end next
`to the chosen operating area on the disc regardless of
`the movement at the other end on the skin.
`It is preferred to use a trocar 12 for insertion of the
`cannula into the channel created by the speculum. The
`trocar adds stiffness to the flexible cannula which cases
`its insertion. It also helps to spread the speculum jaws if
`they have not opened to the desired channel diameter
`due to jaw flexibility.
`To prevent nerve damage, a nerve stimulator of any
`conventional type, such as the VARI-STIM III (regis-
`tered trademark) surgical nerve locator, which is manu-
`factured by Concept, Inc., Clearwater, Fla., may be
`attached or passed down into the cannula or trocar to
`indicate if either instrument is hitting one of the spinal
`nerves or exiting nerve branches. The stimulator will
`cause motion in one of the patient’s legs if it makes
`nerve contact. If the surgeon sees leg movement, he
`may back out the cannula and attempt a slightly differ-
`ent insertion position to manipulate around the nerve.
`FIG. 20 shows a nerve stimulator 80 for use in the pro-
`cedure. A trocar 12 and a cannula 11 with anchor wires
`14 are passed through the skin 82 into a percutaneous
`channel 9. The nerve stimulator has a ground probe 84
`with a needle 85 which is inserted into the skin, and a
`main probe 86, which transmits an electric current of
`about 0.5 to 2.0 ma for nerve detection. The probe 86 is
`applied to the anchor wires 14 and/or the trocar 12, to
`determine whether the working ends of these instru-
`ments are in the vicinity of any nerves. If desired, a
`nerve stimulator could be used whose main probe is
`long enough to extend down the cannula to the working
`ends of the other instruments, or the main probe could
`be extended by means of a separate wire.
`Preferably, the trocar has a pointed tip 13 which is
`stuck into the disc capsule. By sticking the trocar tip
`into the disc capsule 3, lateral movement is prevented
`on the inside end of the cannula relative to the disc,
`enabling the surgeon to maintain stable continuous
`contact with the disc 1 during initial cannula 11 posi-
`tioning. The trocar 12 is guided under fluoroscopic
`X-ray monitoring.
`After the trocar tip pierces the disc, the surgeon re-
`moves the speculum 10 by pulling it out. The cannula 11
`is anchored into the disc after speculum removal to
`prevent minute lateral shearing movement of the can-
`
`11
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`nula tip away from this disc capsule caused by either the
`patient’s or the surgeon’s movement.
`FIG. 6 shows the cannula 11 anchored into a disc
`with anchor means. As shown, the anchor means is one
`or more pieces of wire 14 which are advanced into the
`disc capsule so that they will prevent relative shearing
`movement between the cannula and the disc. Slightly
`curving the wire tips before disc anchoring helps to
`prevent them from spontaneously pulling out of the
`disc, yet they are easily removable at the end of the
`procedure by pulling them out. The anchor wires are
`preferably slid into apertures 15 within the cannula for
`ease of manipulation.
`The anchor means may also be a jig and support arm
`assembly permanently mounted on the operating table
`which positions the cannula and prevents its movement
`relative to the back disc. However, direct anchoring
`into the disc is quick, and less expensive than a jig as-
`sembly.
`Now that the cannula is positioned and anchored into
`the back disc, the surgeon may perform the diskectomy
`procedure or any other surgical procedure on the disc
`that requires access to a disc or spinal column by pass-
`ing instruments through the cannula lumen 16.
`As shown in FIG. 7, a knife 17 is inserted into the
`cannula 1] to cut a hole in the disc capsule, which al-
`lows access to the nucleus material. Instead of using a
`knife, the trocar can have a rotatable reamer built into
`its tip to cut a hole into the disc capsule.
`Once the hole is cut, the knife is inserted through the
`capsule in order to fragment the nucleus cartilage-like
`material. Any shape of knife presently used in known
`diskectomy treatments may be used, but the scimitar-
`shaped blade shown in FIGS. 16 and 16a is much more
`efficient for nucleus fragmenting. While the knife is the
`simplest and probably the most
`inexpensive way to
`chop up the nucleus material, other chopping means
`may be employed, such as ultrasonics, a laser or dis-
`solving chemicals.
`Referring to FIG. 8, a rongeur forceps 18, such as
`those shown in FIGS. 17-19, is inserted down the can-
`nula 11 into the disc to scoop out the fragmented nu-
`cleus material. Alternative means to remove material
`may include other forceps designs or suction. Rongeurs
`are the preferred instruments for removing chopped
`nucleus material because they are simple and quick to
`operate. The rongeur is inserted into the nucleus (under
`intermittent X-ray visualization) and its jaws or scoops
`are opened to scoop up a portion of the fragmented
`material.
`When a section of the nucleus is scooped out and
`removed to form a disc space, the rongeur is reinserted
`in a new area of the nucleus to scoop out more material.
`Maneuvering the rongeur into the new area can be
`difficult because the surgeon has to work through the
`long cannula. Rongeurs which are constructed in accor-
`dance with the teachings of the present invention have
`larger material grabbing jaws that sweep a wider arc
`during actuation than known designs. The jaws may
`also be bent at angles relative to the rongeur shafts.
`Rongeurs of the present invention can have large
`angle jaws because they may pass through the relatively
`large diameter of the cannula lumen without risk of
`injury to other tissue structure. The surgeon has the
`ability to visualize the precise location and movement 65
`of the instrument under X-ray visualization.
`Jaws that sweep a wide arc are helpful in the present
`invention procedure because entry to the disc space is
`
`8
`from the side opposite the disc bulge. The preferred
`practice in diskectomies is to remove nucleus material
`close to the bulge. In the present invention, the surgeon
`must remove material all the way across the disc in
`order to get close to the bulge.
`A surgeon performing this technique will probably
`use a series of rongeurs having heads at various angles.
`Each different head angle will remove nucleus material
`from different portions of the disc. The first rongeur
`used should preferably have a straight head as shown in
`FIG. 17. It tends to smooth the edges of the hole that
`was cut into the disc capsule as it scoops out a portion
`of the fragmented nucleus material. The surgeon will
`then use one or more angle-headed rongeurs to remove
`other portions of the chopped nucleus. Surgeons famil-
`iar with rongeur manipulation will appreciate that the
`instrument may be rotated about an axis defined by the
`shafts in order to scoop out material about an axis of
`revolution.
`‘
`The relatively large diameter cannula allows use of a
`rongeur having jaws mounted at an angle intersecting
`the plane formed by the rongeur shafts. Such jaws are
`shown in FIG. 19, where they are mounted at roughly
`a 90° angle relative to the shafts. This is called a “Z-
`head” rongeur. If the surgeon rotates the Z-head ron-
`geur about the axis formed by the rongeur shaft, he can
`create a cavity of revolution by removing a large
`amount of nucleus material.
`After emptying the disc space of fragmented nucleus
`material, it is flushed with saline solution to clean out
`the space. The solution and any debris contained therein
`are in turn suctioned out of the space.
`The cannula is simply removed after cleaning out the
`disc space by axially pulling it out of the channel. After
`removal the surgeon stitches the fat and fascia under-
`neath the skin. The skin is bandaged with an adhesive
`strip, rather than stitched, to prevent suture scars.
`Since the procedure does not damage blood vessels
`or nerves, post operative pain and complications are
`minimized. Patient recovery has been found usually to
`occur within one to two days. Many patients have been
`able to walk within hours after the operation and out-
`patient convalesence is contemplated for some patients.
`The total time necessary to perform this procedure is
`approximately 15 minutes.
`Instruments for Performing a Percutaneous Lumbar
`Diskectomy
`Surgical instruments constructed in accordance with
`the teachings of the present invention enable the sur-
`geon to quickly and efficiently perform a percutaneous
`lumbar diskectomy.
`FIGS. 9-11 show a speculum 20 used to create the
`lateral cavity through body tissue into which the can-
`nula will be inserted. The speculum 20 has a pair of
`semi-sharp edged blades 21 for piercing and stretching
`body tissue. The semi-sharp edges do not cut tissue, and
`therefore blood loss is reduced to a minimum. The spec-
`ulum has a pair of pivotally hinged handles 22 for open-
`ing and closing the blades. A lock means allows the
`surgeon to lock the speculum with the blades in the
`open position, thus freeing both of his hands. As shown
`in FIGS. 9 and 10, the lock means is a threaded knob 23
`which screws into one handle 22 and contacts the other
`handle 22. When the knob contacts the other handle the
`blades cannot close.
`The speculum 20 has a guide means for guiding the
`speculum along a slender member such as a spinal nee-
`
`12
`
`

`
`30
`
`9
`dle 24 or guide wire having a diameter of less than
`approximately 3 mm, to ensure that the speculum cre-
`ates a properly positioned channel for disc access. The
`guide means is any form of bore or series of axially
`aligned holes defined by the speculum which will slid-
`ably receive the the spinal needle. The bore may be
`incorporated in different embodiments of guide means.
`Other forms of guide means may be a hole in the front
`and rear of the blade tip, which allows passage of the
`spinal needle; a slot on the blade for reception of the
`spinal needle; or a bore drilled through the blade. In
`FIGS. 9-11, the guide means is a tube 25 attached to the
`inside of one of the speculum blades 21. The spinal
`needle 24 will pass through the tube 25 and guide the
`speculum 20 into position. The needle 24 passes through
`a hole 26 in the blade tip.
`The preferred embodiment of the cannula 30 is
`shown in FIGS. 12 and 13. The cannula has a tubular
`member 31. The member defines a lumen, or hole 32, for
`passing instruments therethrough from outside the body
`to inside the body. The member 31 preferably has an
`oval or elliptical cross section, as shown in FIG. 13, to
`allow wider instniments to pass through it. For in-
`stance, rongeurs having large jaws and angled heads
`pass through the lumen 32 by aligning their widest part
`with the major axis of the ellipse. The minor axis is
`dimensioned to clear the vertebra above and below the
`disc. The preferred range of cannula diameters are be-
`tween approximately 8—l9 mm.
`The cannula may be constructed of metal or of any
`material compatible with general surgical sterility and
`mechanical requirements. It is preferably constructed of
`flexible,
`resilient material
`in order to accommodate
`minute bends or stresses caused by the surgeon as he
`manipulates instruments in the cannula. It is also pre-
`ferred that the member material be X-ray transparent so
`that the entire procedure may be watched under a fluo-
`roscope and the member not obscure the disc area. A
`suitable X-ray transparent and flexible member material
`is polyvinyl chloride plastic.
`The cannula has anchor means for anchoring it to the
`disc. As shown in FIG. 12, the anchor means is one or
`more anchor wires 33 which pierce the the disc capsule
`and prevent shearing movement between the disc and
`cannula. In FIG. 13, the anchor wires 33 are slidably
`inserted into one or more bores 34 defined by the mem-
`ber 31.