Method and instruments for performing arthroscopic spinal surgery

A method and apparatus for performing an arthroscopic spinal laminectomy or similar surgical procedure includes a plurality of cannulas which are individually inserted, in a predetermined sequence, into predetermined areas of a patient's spinal column. The first inserted cannula has a tissue manipulating surface thereon which is used to create a working space adjacent a predetermined area of the patient's spinal column. A viewing device is inserted through this cannula and the fluid used in association therewith is used to maintain the working space. The second and third cannulas are larger in size and are working cannulas in that they provide passageways for instruments used in the surgical procedure. The second and third cannulas are utilized by the surgeon to sequentially remove a portion of the ligamentum flavum necessary to expose the desired area of the patient's spinal bone and, if necessary, to remove any portion of bone necessary to expose the nerve and disc area. The nerves are then moved and the sequestered portion of the disc is removed, all utilizing the cannulas as passageways to perform the surgical procedure. In addition to a cannula which has a tissue manipulating surface thereon, the invention includes a rongeur having a cross section shaped to pass through a cannula and with a suction connection therefor so that whatever body tissue and/or bone fragments are cut by the rongeur may be removed by suction through the passageways created by the cannula.

THE FIELD OF THE INVENTION 
This invention relates to a method and instruments to perform an 
arthroscopic spinal procedure and, more specifically, a laminectomy, 
although the techniques and instruments disclosed are also useful in 
performing spinal fusions. 
It is the present practice in performing laminectomies on the spine, 
whether in the cervical, thoracic, or lumbar regions, to follow a 
procedure in which there is some dissection of muscle and tissue by the 
surgeon. Although every attempt is made to minimize such dissection, the 
fact remains that it is necessary and it is a major factor in determining 
rehabilitation time for the patient which can range anywhere from six 
weeks to three months. 
The present invention is specifically directed to applying the arthroscopic 
surgical techniques used on knees and shoulders to spinal surgery and, 
more specifically, to laminectomies. By utilizing arthroscopic techniques, 
muscle dissection is maintained at an absolute minimum and in many 
instances there may be no such dissection and the only invasion of the 
body will be the three small stab wounds necessary to insert the cannulas 
which provide the passageways for the procedure. The utilization of 
arthroscopic concepts in spinal surgery requires instruments not 
heretofore available. Specifically, a cannula is utilized which has a 
tissue manipulating or moving edge thereon which is used to create a space 
for subsequently used instruments. Also, since all of the surgical steps 
must be performed by utilizing cannulas as instrument passageways, it was 
necessary to develop new instrumentation which would pass through cannulas 
and yet still perform the necessary tissue and bone removal, nerve 
movement, and the final retraction of the herniated portion of the disc. 
U.S. Pat. No. 4,545,374 describes a method and instruments for performing a 
percutaneous lumbar diskectomy. In this patent the lumbar region of the 
spinal column is accessed by laterally inserting a cannula through the 
patient's side. This technique has minimum utilization and will not permit 
the removal of approximately 80 percent of herniated discs in which the 
disc is sequestered and for that reason it has not been utilized to any 
substantial extent in performing spinal laminectomies. 
SUMMARY OF THE INVENTION 
The present invention relates to a method and instruments for 
arthroscopically accessing a predetermined area of a patient's spinal 
column and for subsequently performing desired surgical procedures 
thereon. 
Another purpose of the invention is a method of arthroscopically performing 
a spinal laminectomy utilizing a plurality of cannulas, each of which 
provide instrument passages whereby the entire laminectomy may be 
performed with minimum body invasion and only requiring three small 
stab-type wounds for the insertion of the cannulas. 
Another purpose of the invention is a method of performing a spinal 
laminectomy in which a plurality of cannulas are utilized and in which the 
initially inserted cannula has a tissue manipulating or moving surface 
thereon which is used to create a working space for the subsequently 
utilized instruments which will pass through the other cannulas. 
Another purpose of the invention is to provide techniques for performing 
spinal laminectomies requiring the absolute minimum tissue and muscle 
dissection. 
Another purpose of the invention is to provide a surgical technique for 
obtaining access to a predetermined area of the spinal column utilizing a 
plurality of cannulas as the instrument passages. 
Another purpose of the invention is to provide a cannula for use in the 
surgical procedure described having a tissue moving or manipulating 
surface at one end thereof which is utilized to create a working space for 
subsequently applied instruments. 
Another purpose of the invention is to provide rongeur cutting instruments 
having a cross sectional area of a size and shape to pass through cannulas 
for use in performing spinal surgical procedures utilizing arthroscopic 
techniques. 
Another purpose of the invention is to provide a Kerison rongeur having 
suction capabilities for removing tissue and/or bone in the described 
surgical process. 
Another purpose of the invention is to provide a surgical cutting 
instrument having a cross section shape and size adapted for use in 
surgical techniques in which the instrument must pass through a cannula 
and all subsequent manipulation thereof must be done through the cannula. 
Other purposes will appear in the ensuing specification, drawings and 
claims.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The invention will be described specifically in connection with a 
laminectomy in the lumbar region of the spine. It should be understood 
that the surgical technique described, as well as the disclosed 
instruments, may be used in performing spinal laminectomies utilizing 
arthroscopic techniques on the cervical and thoracic areas of the spine, 
as well as performing other surgical procedures, more specifically, spinal 
fusions. 
In spinal laminectomies as this surgical procedure is currently performed, 
it is necessary to have some dissection of tissue and muscle to access the 
herniated disc. Even though every effort is made to minimize such 
dissection, it is necessary in order to obtain access to the disc and to 
insert the instruments necessary for removal of the sequestered portion of 
the disc. It is the dissection of the muscle and tissue and the associated 
trauma which determines the patient rehabilitation time. The less invasive 
the procedure, the quicker the patient will return to full activity. 
Rehabilitation time is meant to include not only time in the hospital, but 
the time before the patient can return to full time work or other 
activity. 
It is present-day practice to perform arthroscopic surgical procedures on 
certain areas of the body, specifically the knee and shoulder, and these 
procedures, since they involve minimal invasion of the body, usually by 
puncture wounds, may be done on an outpatient basis, eliminating time 
spent in the hospital, and also substantially reducing the rehabilitation 
time before the patient returns to full time activity. The present 
invention is specifically directed to utilizing the concepts of 
arthroscopic surgery in performing spinal laminectomies and/or fusions. 
Before describing the surgical procedure, certain instruments which were 
not heretofore available will be described, which will lead to a fuller 
understanding of the surgical techniques. 
In FIGS. 9 and 10 there is a cannula having a body 10 which is cylindrical 
in form and may be of a size utilized in arthroscopic knee and shoulder 
surgery. Body 10 has an internal cylindrical passageway 12 to accommodate 
a viewing scope and the fluid necessary for proper utilization of the 
scope. The body 10 may have an enlarged end 14 and a threaded end 16 for 
use in attaching the desired viewing instrumentation. Of specific 
importance in the cannula of FIGS. 9 and 10 is the interior end 18 which 
will be inserted into the patient's body in the desired location. There is 
a cutting edge 20 which may be termed a tissue manipulation or moving edge 
as it will perform more in the nature of tissue movement than it will 
tissue cutting or dissection. The edge 20 extends both radially and 
axially of the body 10. Looking particularly at FIG. 10 it should be noted 
that the arcuate edge 20 extends radially outwardly of opposite sides of 
the body 10 and has walls 22 which extend from the end 20 to the body and 
provide strength and integrity to the tip or cutting edge. As shown 
particularly in the side view of FIG. 9, the cutting edge 20 bends 
substantially radially beyond the circumference of the body with the 
exterior surface of the end flowing smoothly from the body to the cutting 
edge 20. There is a wall 24 which in part provides the opening connecting 
passageway 12 with the end of the cannula. By movement of the cannula once 
inserted, the surgeon can utilize the edge or surface 20 to manipulate the 
tissue and muscle as will be described subsequently herein. 
FIGS. 5 through 8 disclose a Kerison rongeur suction punch. Kerison rongeur 
instruments are known in the art, as are suction instruments, which are 
commonly used in a number of surgical procedures. The instrument of FIGS. 
5 through 8 combines a Kerison rongeur with a suction adapter so that 
particles removed by the cutting action of the instrument may be 
eliminated from the working area. Of particular importance is the fact 
that the cross sectional area of the Kerison rongeur is of a size and 
shape to pass through a cannula. In this connection, the invention 
encompasses other types of surgical cutting instruments which do not have 
suction connections therefor, but which have a cross sectional area of a 
size and shape so that they may pass through working cannulas to reach the 
area of interest for the surgeon. 
In FIGS. 5 through 8 the instrument has a body 30 which has a suction 
connection 32 at one end thereof and a cutting tip 34 at the opposite end 
thereof. The body 30, which is cylindrical in a major portion of its 
length, has an axially extending passage 36 which connects to the suction 
attachment 32 and, as particularly shown in FIGS. 7 and 8, is radially 
offset from the axis of the body. Body 30 has a recess 38 adjacent the 
cutting end 34 to form a trough 40 which functions as a receptacle for 
severed tissue and/or bone prior to such particles being drawn through the 
suction passage 36. Body 32 is attached to a fixed handle element 42 by a 
pair of fastening elements 44 which connect the platform portion 46 of the 
fixed handle 42 to the underside of the body. 
Coaxially mounted on body 30 is a movable sleeve 48 which has a cutting 
edge 50 at one end thereof which cooperates with the cutting edge 34 to 
sever pieces of tissue and/or bone upon coaxial movement of the sleeve 48 
relative to the body. Sleeve 48, as particularly shown in FIGS. 7 and 8, 
has a round cross section throughout a major portion of its length so that 
it may be received within a cannula to perform certain surgical procedures 
while so positioned. Sleeve 48 has an enlarged portion 52, illustrated in 
FIG. 8, and which, as shown, may be generally square in cross section, but 
could be otherwise. The enlarged portion 52 is pivotally attached through 
a slot 54 to an arm 56 of a movable handle 58. Handle 58 and the fixed 
handle 42 are pivotally attached together, for example by a screw 
connection 60. A pair of cooperating and interconnected leaf springs 62 
and 64 bias the handles 42 and 58 to the open position of FIG. 5. When the 
handles are squeezed together, against the action of leaf springs 62 and 
64, sleeve 48 will slide to the right, in the direction of arrow 66, so 
that the cutting edges 50 and 34 are brought together. These edges are 
sharp and the bringing together of these edges, as in a typical Kerison 
rongeur type of cutting action, will sever whatever is positioned between 
them. 
Of importance in the instrument of FIGS. 5 through 8 is the fact that the 
cross section of sleeve 48 and that portion of the instrument where the 
cutting action occurs is round or circular so that it will loosely fit 
within a working cannula. All functions of the instrument are performed 
while it is so positioned and it is thus necessary that the cross section 
of the major portion of the pistol grip Kerison rongeur suction punch 
described match the interior of the cannula. Suction attached to fitting 
32 is effective to remove any particles which are severed by the described 
cutting action. 
The surgical procedure is illustrated on a step-by-step basis in FIGS. 1 
through 4. As indicated earlier, the procedure will be described in 
connection with an arthroscopic spinal laminectomy, although the 
techniques described essentially provide arthroscopic access to an area of 
the spine and a fusion or other procedure may also be performed using the 
instruments and techniques described. In FIG. 1 the outer skin of the 
patient is indicated at 70 and muscle and other tissue is indicated at 72. 
The bone of the spinal column is indicated at 74 and spinal discs are 
indicated at 76. The initial step in the procedure is to insert a cannula 
78 which is of the type illustrated in FIGS. 9 and 10 through the skin, 
tissue, and muscle into an area adjacent to and spaced laterally from the 
spinal column. More specifically, as shown in FIGS. 1 and 2, the cannula 
78 is inserted through the outer skin 70 and muscle 72 in a generally 
posterolateral direction relative to the spinal column 74. A viewing scope 
will be passed through the cannula and fluid will be supplied from a 
source 80 along a line 82 so that fluid passes through the cannula 80 to 
an area 84 at the end of the inserted cannula. The surgeon may utilize a 
viewing screen 86 to have a full picture of the area in which the interior 
end of the cannula is working. The purpose of the cutting or tissue moving 
end of the cannula is so that the surgeon may manipulate it to create the 
working space 84. This is done by moving muscle and/or tissue rather than 
cutting it and the pressure of the fluid which is utilized in the viewing 
scope, which is of a type conventional in arthroscopic surgery, will 
maintain the space once it has been created. The pressure of the fluid 
within space 84 will keep or maintain the muscle and tissue away from the 
area in which the surgeon wishes to work. 
Once the space 84 has been created as described, a second cannula 88, 
having an internal diameter slightly greater than the cannula 78, is 
inserted generally between the cannula 78 and the midline of the spinal 
column 74 as illustrated particularly in FIG. 2. The space 84 which was 
created as described above exposes the ligamentum flavum illustrated at 90 
in FIG. 2 and the next step in the procedure is for the surgeon to insert 
a cutting tool, such as that illustrated at 92, having a cutting end 94 
through working cannula 88. Ligamentum flavum is an elastic tissue which 
spans the space between adjacent vertebrae as particularly illustrated in 
FIG. 2. The cutting element or curette 92 will incise the ligamentum 
flavum, for example by making a slit at the superior edge of the inferior 
lamina. Once this slit has been made, the Kerison rongeur suction punch 95 
illustrated in FIGS. 5-8 will be inserted through cannula 88, as 
illustrated in FIG. 3, to remove sufficient portions of the ligamentum 
flavum to expose the bone beneath it. In some instances it may be 
necessary to use the Kerison rongeur suction punch to actually remove 
portions of bone, as what is required is that the ligamentum flavum and/or 
bone be removed to a sufficient extent to expose the spinal nerves 
indicated generally at 96. Note particularly the opening 98 in the 
ligamentum flavum in FIG. 3. 
At this point in the procedure the disc is accessible to the surgeon and 
the herniated portion of the disc indicated at 100 can be removed. The 
first step in removing the sequestered fragment 100 of the disc is to move 
nerves 96. This is done by inserting an instrument 102, illustrated in 
FIG. 4, through cannula 88 and gently slipping the hooked end 104 beneath 
the nerves and moving the nerves a sufficient distance to provide complete 
access to the sequestered portion 100 of the disc. Once the nerves have 
been so moved, a third cannula 105 is utilized. This cannula may be 
inserted at any point in the procedure once the nerves and bone have been 
exposed by removal of the necessary portion of the ligamentum flavum. 
Cannula 105, again a working cannula and of essentially the same internal 
diameter as cannula 88, will provide an access passage for a grabbing or 
clamping instrument 106 which has an operating end 108 of the type to 
grasp the sequestered portion 100 of the herniated disc and remove it. The 
herniated portion of the disc is then withdrawn through cannula 105. The 
relative positions of the three cannulas will vary depending upon the 
exact location of the damaged area of the spinal column. The positions 
shown in FIGS. 1-4 are merely illustrative. 
Approximately 80 percent of herniated discs are sequestered which means 
that the herniated portion has actually broken away from the body of the 
disc. Even in those instances in which the herniated portion is not 
sequestered, it still may be removed as described. In some instances it 
may be necessary, prior to removing the herniated portion of the disc, to 
use a knife again inserted through the third cannula 105, to excise any 
tissue which may be overlying the disc. The important point, however, is 
that all of the described steps in the surgical procedure are performed 
arthroscopically through the described cannula passages and the various 
tools which may be necessary to first expose the nerves, then move the 
nerves, and then grasp the herniated portion of the disc, will all be 
utilized in the cannula passages described. 
Once the steps described above have been completed and the herniated 
portion of the disc has been removed, all that remains is for the surgeon 
to withdraw the cannulas and suture the puncture wounds which were the 
only invasions of the body necessary for the entire surgical procedure. 
Of importance in the procedure described is the minimal movement of body 
tissue and muscle and the lack of any incising or cutting of body tissue 
and muscle. This substantially reduces rehabilitation time and will permit 
the operation to be performed on an outpatient basis. 
Although the procedure has been described in connection with a laminectomy, 
it should be clear to one skilled in the art that once the area of the 
bone is exposed as described, bone particles and/or bone segments for a 
fusion may also be inserted through a cannula and properly positioned for 
that type of procedure. Again, the procedure is not limited to access of 
the lumbar region of the spine, but may be equally utilized in the 
cervical or thoracic areas of the spine. 
Whereas the preferred form of the invention has been shown and described 
herein, it should be realized that there may be many modifications, 
substitutions and alterations thereto.