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Background of Scientific Testing and Clinical Outcomes
Peer-reviewed literature for disc herniation, first reported by Mayer and Brock[19] in 1993[3] then
by Hermantin[2] in a prospective randomized study, has concluded that the results with
transforaminal endoscopic (coined “arthroscopic” by Kambin[20]) diskectomy in the lumbar spine
are generally similar to those with open diskectomy, but with significantly less surgical morbidity
and quicker recovery (Table 64-1). The YESS technique evolved from the original Kambin
technique as Yeung originally learned from Kambin. The procedure, done on an outpatient basis,
utilizes local anesthesia with sedation. Patients are usually discharged an hour after surgery. Results
show that patients use less postoperative pain medication and return to work within 1 to 6 weeks. It
is not unusual for individual patients to return to work in a matter of days. Long-term follow-up has
demonstrated decreased recurrence (6%), less postlaminectomy syndrome, and greater patient
satisfaction overall. Morganstern, a student of Yeung[21], has reported[6] that after a learning curve
of approximately 70 patients utilizing the YESS technique for a wide spectrum of disc herniation
types, a 90% overall good/excellent result by MacNab and modified MacNab criteria is achievable.
The 90% standard was the goal established for endoscopic surgeons wishing to take up the
procedure. The results for all types of herniated nucleus pulposus (HNP), through 2008, as reported
in the literature are summarized in Table 64-2.
TABLE 64-1 -- Microdiskectomy versus Endoscopic Diskectomy[∗ ]
SURGICAL OUTCOME
Level II-III
Evidence
Group 1: Arthroscopic
Microdiskectomy
Group 2: Microscopic
Diskectomy
Satisfactory outcome 97%
93%
“Very satisfied”
73%
67%
Disability
27 days
49 days
Narcotic use
7 days
25 days
Hospital stay
0 day
1 day
From F.U. Hermantin ,T. Peters, L. Quartararo, et al. A prospective randomized study comparing
the results of open discectomy with those of video-assisted arthroscopic microdiscectomy. Journal
of Bone and Joint Surgery 81A ( 1999 ) 958 – 965.
∗
Sixty patients randomized, 30 per group.
TABLE 64-2 -- Results of Arthroscopic Diskectomy[∗ ] versus Microdiskectomy
Author(s)
Number of Type of Treatment
Patients
(Indications)
Mean Age Mean
(range)
Follow-up
(range)
Results MacNab
Good/Excellent[†]
Mayer (1993) 20
Contained HNP Small
protrusion Single
NR
NR
80%
Kambin
(1999)
Small protrusion
Contained/extruded
HNP
NR
NR
97%
Yeung (2000) 500
All patient groups
42 25-69
NR
86%
Lew/Mehalic 49
(2001)
Far lateral HNP
NR
NR
85%
Yeung (2001) 307
HNP—all types All
patient groups
NR 18-72 23 NR
84%
Tsou/Yeung
(2002)
219
HNP with neurologic
deficit
NR
NR
93%
Ruetten
(2005)
463
All HNP
NR
NR
81%
Choi/Lee
(2007)
41
Extraforaminal HNP
58.7 32-74 34.1 NR
Ruetten
(2008)
178
All HNP
43 20-68
NR 1-24 mo 82%
Hoogland
(2008)
262
Recurrent HNP
NR
NR
60
92%
86%
∗
Term coined by Kambin; later used generically to denote endoscopic foraminal diskectomy. ( P.
Kambin, Arthroscopic microdiskectomy. Mt Sinai J Med 58(2) (1991) 159-64).
†
MacNab criteria: Good—occasional back or leg pain not interfering with normal work or
recreation; Excellent—no pain, no restriction of activity.
The YESS endoscopic transforaminal approach, described in this chapter, also addresses a wide
spectrum of painful degenerative conditions of the lumbar spine. The results of highly selected
patients for these painful conditions have been reported at national and international spine meetings,
but the clinical results of endoscopic treatment contained and noncontained HNP studies were last
reported in 2004. Over 3,000 cases recorded on an excel database ranging from 1- to 10-year
follow-up using clinical standardized measurements such as visual analog scale (VAS), Oswestry
Disability Index (ODI), SF 12 (lifestyle disability scale), and MacNab criteria are currently being
collated independently for peer-reviewed publication.
The endoscopic foraminal approach, differentiated from the posterior approach, emphasizes the
dilation along tissue planes without damage to normal anatomy. The foraminal approach for disc
herniation utilizing the “inside-out-technique” provides easy access for central, paracentral, and
subligamentous foraminal and extraforaminal disc herniations through natural tissue planes between
the longissimus and psoas muscles (Figure 64-3). For foraminal and large paracentral herniations, it
is easy to visualize the lateral edge of the traversing nerve (Figure 64-4) once the herniation is
removed. If the fragment is large and extruded, it comes out as an intact collagenized fragment.
Prodromal symptoms of disc herniation in the aging spine usually arise from annular tears, which
cause recurrent back pain and sciatica before the disc herniates. The opportunity to study and treat
painful annular tears endoscopically that do not heal naturally provides information on validating
the theory of electrothermal therapy but also sheds light on the reasons why the usefulness of blind
radiographic methods will always be limited. Identification of granulation tissue and nucleus
material in the annular layers (Figure 64-5A) provides a good prognosis for those tears treated with
thermal annuloplasty. The nucleus material that weakens the annulus must be removed before the
annulus is cauterized to close the tear. Using a biportal approach and a 70-degree scope,
cauterization and confirmation of successful thermal annuloplasty under direct endoscopic
visualization provide confirmation that the tear is closed and sealed (Figure 64-5B).
FIGURE 64-3 Basic “Inside-Out-Technique” for Endoscopic Disc
Decompression. Uniportal technique for selective endoscopic
diskectomy. After introduction of a beveled cannula, endoscopic
microrongeurs are used for visualized fragmentectomy. This is followed
by use of specialized hinged rongeurs and straight and flexible shavers
to remove the soft nucleus from the annular herniation defect.
(Reprinted from Yeung CA, Hayes VM, Siddiqi FN, Yeung AT. Lumbar
endoscopic posterolateral (transforaminal) approach. In Motion
preservation surgery of the spine. Yue JJ, Bertagnoli R, McAfee PC, An
HS (eds). Philadelphia, Saunders/Elsevier, 2008.)
FIGURE 64-4 Traversing Nerve after Removal of a Extruded
Foraminal HNP. Indigo carmine dye stains the degenerative nucleus
blue, helping the surgeon to selectively remove not only the extruded,
sequestered disc herniation, but also the loose degenerative disc
material, which could become the source of a recurrent herniation.
Here, the decompressed traversing nerve is clearly visualized to
confirm complete decompression of the herniation. Intraoperative or
postoperative CT scan or MRI is not needed to confirm complete
decompression of the spinal nerve when visual confirmation confirms
successful removal of the herniation. The real-time extraction of the
herniation fragment, followed by direct visualization of the
decompressed nerve, confirmed by the conscious patient providing
immediate feedback reporting immediate relief of leg pain, precludes
the need for traditional evidence based medicine calling for a doubleblind, randomized study to validate the selective endoscopic
diskectomy technique or any visualized endoscopic technique designed
to address the pathoanatomy.
FIGURE 64-5 Endoscopic Thermal Annuloplasty of Annular Tears. A,
Painful annular tear identified endoscopically after intraoperative
chromo-diskography confirms the presence of a grade IV annular tear
with disc tissue embedded in the annular fibers. Tears that don’t heal
have imbedded disc material preventing the tear from healing naturally.
The nucleus material must be removed from the annular layers before
the results of thermal annuloplasty is predictable. This is the reason the
surgical results of IDET is not predictable. Selective endoscopic
diskectomy removes degenerative disc material as well as the nucleus
embedded in the annulus. Endoscopic thermal annuloplasty follows.
Tears vary in size, location, and type. One or two quadrant posterior
and posterolateral tears in patients with 20% to 25% remaining annular
thickness have good long-term results following endoscopic thermal
annuloplasty. More extensive tears will also heal, but can tear again.
Painful annular tears are best diagnosed with Evocative ChromoDiscography and confirmed by endoscopic visualization of the tear.
Diskography performed by the surgeon evokes the pain, while the
indigo carmine dye helps locate the tear. Granulation and inflammatory
tissue are often found adjacent to the tear, and visual documentation of
tear closure provides evidence of endoscopic thermal annuloplasty in
the treatment of painful annular tears as a source of pain in the aging
spine. B, Illustration of selective endoscopic diskectomy and thermal
annuloplasty technique for a grade IV Tear. C, Grade III-IV annular tear
cauterized and closed with bipolar radiofrequency thermal annuloplasty
as viewed through a 70-degree scope. The prognosis for this tear is
good because the tear is completely closed, and 20% to 24% of the
annulus is still preserved after closing the tear.
The technique for endoscopic foraminoplasty in more advanced disc degeneration and foraminal
narrowing is associated with central and foraminal stenosis, not only for lateral recess stenosis but
also for foraminal decompression of the ventral facet in tall discs to gain “inside-out” access to
sequestered herniations in the epidural space. A foraminoplasty cannula exposes the ventral aspect
of the superior facet for endoscopic decompression (Figure 64-6A), which helps strip the capsule
and define the undersurface of the facet to be removed with trephines and burrs (Figure 64-6B).
Degenerative spondylolisthesis is often associated with disc protrusions and lateral stenosis,
whereas sciatica from isthmic spondylolisthesis, due to the mechanical compression of the axilla
and subarticular recess (Figure 64-6C), is effectively treated by endoscopic foraminal
decompression in selected patients. These patients usually improve temporarily with foraminal
diagnostic and therapeutic injections. Endoscopic decompression of the foramen can provide
enough relief that the patient will avoid fusion. Failed back surgery syndrome (FBSS) patients with
lateral recess stenosis and recurrent disc herniation also respond well. When the support is shifted
posteriorly to the facet joints, synovitis and facet cysts may form. These cysts may impinge on the
spinal nerves. Pedunculated cysts are sometimes visualized endoscopically, especially if the cyst
wall is stained by indigo carmine or is visualized in the course of a diskectomy for chronic sciatica
(Figure 64-7). Degenerative and isthmic spondylolisthesis (Figure 64-8A-D) can also be treated
endoscopically with proper interventional injection workup. Impingement from the disc or superior
facet of the inferior vertebra can be sorted out with diagnostic and therapeutic injections. If
evocative diskography evokes concordant back pain and/or sciatica, and foraminal epiduralgrams
and therapeutic injections provide information of the pathoanatomy, then careful preoperative
planning will provide information on the likely outcome of foraminal decompression.
FIGURE 64-6 A, Endoscopic foraminal decompression. In more
advanced aging, foraminal stenosis and osteophytosis can cause
impingement of the spinal nerves. A specially configured cannula is
placed under the facet for foraminal decompression. A side-firing laser
is useful to strip the capsule from the facet; then a trephine and highspeed diamond burr are used to decompress the ventral portion of the
facet to enlarge the foramen and elevate the foraminal window to gain
access to the epidural space. The exiting nerve is then followed into the
epidural space to decompress the axilla between the traversing and the
exiting nerve. Decompression continues until the lateral edge of the
traversing nerve is visualized or until fat is seen in the foramen. B,
Foraminal decompression may be performed in conjunction with disc
decompression or as a stand-alone procedure. Here, the illustration
demonstrates the use of the holmium:yttrium-aluminum-garnet sidefiring laser to strip the capsule from the ventral facet. More extensive
decompression may be further performed with trephines, endoscopic
Kerrison rongeurs, high-speed endoscopic burrs, or rasps. C,
Decompressed exiting nerve for lateral recess stenosis. A high-speed
diamond burr was used to complete the superior facet decompression to
free the exiting nerve by stripping the facet capsule and removing 4 mm
from the ventral surface of superior facet.
FIGURE 64-7 Pedunculated Synovial Cysts. Pedunculated cysts may
be difficult to see on MRI because they may vary in size and are
sometimes seen incidentally during foraminal surgery. It does not have
to be located adjacent to the facet joint, because the cyst may be medial
or lateral to the joint. Here the cyst, accompanied by a plexus of blood
vessels, is found in the foramen compressing the exiting nerve. Usually
a cyst is suspected from the finding of a bright signal adjacent to the
facet capsule.
FIGURE 64-8 Both isthmic and degenerative forms of spondylolisthesis are
treatable endoscopically if the pain generator can be demonstrated to come from the
disc or foramen. A, Lateral MRI demonstrates a degenerative spondylolisthesis with
a disc protrusion contributing to central stenosis. The disc can be decompressed
endoscopically, but the risk of instability with further slippage is increased. B, There
is foraminal stenosis causing sciatica. This patient had right sciatica, not left; good
relief was obtained with a foraminal epidural block on the right. C, Endoscopic
foraminoplasty identified impingement of the exiting nerve by the tip of the superior
facet of the inferior vertebra. D, A furcal nerve was found in the foramen, possibly
also contributing to the patient’s sciatica. His sciatica resolved following foraminal
endoscopic decompression.