I
Minimally
Invasive Spine Surgery
What
Is Minimally Invasive Spine Surgery?
In
essence, minimally invasive spine surgery is the performance of surgery through
small incision, usually with the aid of microscopes or endoscopic visualization
(i.e., very small devices or cameras designed for viewing internal portions of
the body).
Why
Is Minimally Invasive Spine Surgery Needed?
Minimally
invasive spine surgery has developed out of the desire to effectively treat
disorders of the spinal discs with minimal muscle related injury, and with rapid
recovery.
Traditionally,
surgical approaches to the spine have necessitated prolonged recovery time. For
example, prior to the use of the operating room microscope a large incision was
used to visualize the herniated lumbar disc. In order to perform this procedure,
large sections of the back muscles are moved away from their spinal attachments.
First,
this surgical approach (i.e., dissecting the muscles) produces the majority of
the perioperative pain and delays return to full activity. The degree of the
perioperative pain necessitates the use of significant pain medication with
their inherent side effects. Also, the degree of the perioperative pain delays
return to normal daily activities and nonphysical work.
Second,
the dissection of the paraspinal muscles from their normal anatomic points of
attachment results in a healing by scarring of these muscles. The various layers
of the individual muscle scar to one another losing their independent function.
In
addition, it has been found that this type of dissection sometimes results in
the loss of innervation (i.e., the supply of nerve stimulation) of the muscles
with subsequent wasting away. A permanent weakness of the back muscles results.
This weakness itself may be symptomatic (as a back fatigue-type pain) and/or
limit the patient's function - particularly in those who perform physical
work.
Clearly,
with such significant muscle injury associated with surgical approaches to the
spine, the need existed for the development of less invasive surgical
techniques. It was envisioned that minimally invasive techniques would offer
several advantages including: -Reduced surgical complications - Reduced surgical
blood loss - Reduced use of post-op narcotic pain medicines - Reduced length of
hospital stay - Increased speed of functional return to daily activities
History of Minimally Invasive
Disc Surgery
In
1964—Lyman Smith, an orthopedic surgeon in Chicago, was the first to inject,
percutaneously, chymopapain into a patient with sciatica with the purpose of
hydrolyzing the mucoprotein of the herniated nucleus pulposus.
In
1975 Hijikata performed a percutaneous nucleotomy by inserting a 7-mm diameter
tube down to the annulus fibrosis and, then, using specially designed forceps
removed disc material.
In 1977-78 Yasargil, Caspar and Williams pioneered
the use of the operating microscope and microsurgical techniques for treating
lumbar disc disease.
In
1983 Kambin began developing what eventually would be a modified arthroscopic
approach to lumbar discectomy using a working sheath with a 6.5 mm outer
diameter and coring instruments and forceps designed for a 5 mm inner access.
Onik
and subsequently Maroon and Onik described and published their early results
with automated percutaneous discectomy using a guillotine like 2 mm probe
inserted fluoroscopically into the disc space.
In 1987 Choy and Asher described laser
discectomy and subsequently laser energy has been used percutaneously for disc
ablation.
In 1993 Mayer and Brock discussed the use of the
endoscope for percutaneous discectomy. Subsequently
Smith and Foley designed instrumentation and endoscopic equipment to perform a
micro-endoscopic approach to lumbar disc removal.
In 2000, intradiscal electrothermal energy as well as
newly designed lasers are being advocated for percutaneous thermal annuloplasty
in patients with low back pain.
Summary
of Microscopic Approach
In
1965-66 Gazi Yasargil spent 14 months with R. Peardon Donaghy at the University
of Vermont developing the microsurgical instrumentation and techniques that
would revolutionize the surgical approach to many neurosurgical diseases.
Upon returning to Zurich 1n 1967, he
applied his knowledge and microsurgical skills to reduce the morbidity and
improve the outcome in patients with aneurysms, arteriovenous malformations,
various neoplasms—and herniated lumbar discs.
The
first publication of the microsurgical discectomy procedure was in 1977 in the
journal, Advances in Neurosurgery. It
was Williams, a Las Vegas neurosurgeon and consultant to many of the casinos
employing female dancers, that popularized the technique in the United States.
He supported his hypothesis that surgical scars could be
minimized and performers could return to dancing quicker through
techniques he described in his 532 reported patients.
Subsequently Goald and Ebeling, et al, Wilson and Harbaugh, Maroon and
many others have confirmed the ability to reduce incision size, blood
loss and morbidity with the microsurgical technique.
Success rates of microdiscectomy range from 88% to 98.5%
in various series.
Because of the small incision, the diminished trauma to
lumbar musculature, the easier identification of deep seated structures, the
minimal traumatic manipulation of neural structures and the direct view into the
disc with magnification and coaxial illumination, for the most part, this
resistance has faded and the great majority of neurosurgeons now use
magnification if not the operating microscope in performing lumbar disc surgery.
Our surgical
approach is similar, with a few modifications, to that described by Yasargil,
Caspar and Williams. Patients are placed in the lateral decubitus position,
slightly flexed with the affected side up and the surgeon is seated.
X-ray is used to confirm the correct interspace.
Prophylactic intravenous antibiotics are given in one dose at least 30
minutes prior to the skin incision. A
15-25 mm skin incision is made.
The
operating microscope with a 300-mm objective is then brought into use.
A low profile, high speed drill is used to drill a small window in the
bone. Free fragments and attached disc material are removed and
pressure is released from the nerve root. And the bony opening which the
nerve pasts is also enlarged. Steri strips and a band-aid are
applied to the wound.
Patients are
urged to ambulate immediately and are discharged within 23 hours, either the
same day or the following morning in 95% of the cases.
Our results have not significantly changed since our earlier report.
The average operating time is less than one hour.
Approximately 90% of patients obtain good to excellent pain relief.
Complications such as dural tears, nerve root injury and discitis are
under 1.5%. Long term reoperations
at the same level are under 5%. No
transfusions, great vessel or retroperitoneal injuries or mortality has occurred
in over 2,500 operations.
Conclusion
and Comparisons
When one compares the surgical outcome and overall
experience with microsurgical discectomy with percutaneous techniques such as
chemonucleolysis, automated percutaneous lumbar discectomy, modified nucleotomy
and transforaminal endoscopic techniques the microsurgical approach appears to
be superior in most areas. Obviously,
laser discectomy has no place with extruded or sequestered fragments and none of
the other techniques deal with lateral recess or foraminal stenosis, hypertrophy
of the ligamentum flavum or osteophytes that occasionally are encountered
unawares.
A valid
comparison can be drawn between the micro-endoscopic technique and the strict
microsurgical method. Proponents of
MED assert that the primary differences with the microsurgical approach are 1) a
smaller skin incision, 2) a muscle splitting rather than a subperiosteal
approach to the lamina, 3) less postoperative pain, 4) faster hospital discharge
and 5) a quicker return to employment. Once exposure through the tubular endoscopic system is
obtained, the endoscopic technique for ligamentum flavum removal, discectomy and
foraminotomy are the same as that used in the microsurgical approach.
With the microsurgical approach described above virtually
the same size surgical incision is made, 15-20 mm, and the same surgical
technique is used for discectomy. The
primary difference, therefore, is a subperiosteal dissection versus a muscle
splitting dissection which, in our opinion, is minor. Many
have demonstrated the incision size, hospital stay and results are at least
equivalent to that reported with the MED system.
The return to work interval is also comparable.
Dr. El Kadi and his Associates have spent the last 25
years investigating and reporting on minimally invasive approaches to the lumbar
disc. They believe there still are
indications for APLD, disc ablation with lasers, endoscopic techniques and
nucleotomy in very carefully selected patients.
Despite the relative ease of performance in some cases, however, none of
these methods have found their place in the hands of the majority of surgeons
due either to the paucity of long term results, the potential and real
complication rate or the learning curve in acquiring the technical skills.
With the tremendous advances in neuro imaging, better understanding of
the pathophysiology of disc disease and the innovations in technological
development, pursuit of unique and minimally invasive ways to treat lumbar disc
disease must continue.
Nevertheless, microsurgical discectomy remains the procedure of choice for
the majority of patients requiring surgery and continues to be the standard
against which all other procedures must be measured.
Call, toll-free, at 412-630-7640 or 877-635-5234 to learn more.
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