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Dorsal Endoscopic Rhizotomy for Chronic
Nondiscogenic Axial Low Back Pain
Anthony T. Yeung, Yinggang Zheng, and Christopher A. Yeung
65
k e y p o i n t s
e dorsal ramus branches off the origin of the spinal nerve and sends off
medial, intermediate, and lateral branches to innervate the facet joint and the
tissues surrounding the facet.
e medial branch, going to the facet joint at the level of the transverse
process and one level below, is usually protected by periosteal tissue or an
osseous tunnel as it crosses the transverse process to innervate the facet joint
of two spinal segments.
Dorsal endoscopic rhizotomy is more surgically effective than percutaneous
electrode radiofrequency for ablation of the nerves innervating the dorsal
column.
Visualization of the medial, intermediate, and lateral branches of the dorsal
ramus provides direct surgical confirmation of nerve ablation.
e results of a prospective nonrandomized study concluded that endoscopic
rhizotomy is a safe and effective technique to treat chronic, facet-mediated
axial back pain.
INTRODUCTION
Traditional treatment of low back pain from an aging spine encompasses
many techniques. When surgery is contemplated, diskectomy, laminectomy, and fusion are the most common surgical procedures utilized. Diskectomy, the most common surgical procedure for sciatica and back pain,
may exacerbate the back pain, especially when there is concomitant spinal
instability. Chronic back pain may therefore be a consequence following
surgical diskectomy. Natural progression of the degenerative process also
results in lumbar spondylosis, facet arthrosis, spinal stenosis, and spondylolisthesis in the time line of an aging spine, which may also be the source
of pain generation. The costs of surgical procedures to correct these conditions vary widely, depending on the surgical procedures chosen and implemented by the surgeon. Fusion, the traditional procedure for back pain, is
usually recommended with caution because of its surgical morbidity and
high cost. Failed back surgery syndrome (FBSS), with a paucity of effective
salvage procedures, then result when surgical treatment fails. One recent
study by Katz
ments of back pain in the United States are over $100 billion. This cost
estimate does not even consider the difficult-to-calculate economic loss
due to loss of productivity from disabling low back pain. Back surgeries
to relieve back pain, however, continue to steadily increase in the United
States, partly because of expansion of surgical techniques and implants
used to facilitate fusion. Hazard
bers from 300,413 in 1994 to 392,948 in 2000. Though the majority of
these surgeries are successful in relieving back pain, a significant percentage is not. Some studies estimate that, at best, only 60% of these surgeries
are successful.
Outcomes Research Trial (SPORT),
1
estimated that the annual costs associated with all treat-
2
documented an increase in these num-
3,4
These data, along with the data reported in the Spine
5
demonstrate that although most
spine surgeries are cost-effective, even the 2-year results for degenerative
spondylolisthesis, the premier indication for one-level fusion, is questioned.
With good patient selection, accurate diagnostic criteria, and a low cost, a
minimally invasive surgical option, addressing just the innervation of the
facet-mediated pain generator, may be a viable minimally invasive procedure
to be considered before the definitive surgical fusion or joint replacement
option is considered.
The Yeung Endoscopic Spine Surgery (YESS) decompressive approach,
described in Chapter 64, details a transforaminal endoscopic approach that
utilizes a minimally invasive surgical technique enabling disc and foraminal
decompression as well as ablation of painful nerves and removal of chemical mediators in the disc, annulus, and foramen. Presumed primary sensory
nerves innervating the disc and facet can be ablated, and pathologic conditions causing inflammation (and, therefore, pain) are addressed. The technique, expanded to target denervation of the branches of the dorsal ramus
responsible for facet mediated pain, is the subject of this chapter.
Lumbar spondylolysis, facet arthrosis, spondylolisthesis, both isthmic
and degenerative, that may also be associated with spinal stenosis, are traditionally treated with open decompression, dynamic stabilization, or fusion. A
recent article by Weinstein et al,
concluded that degenerative spondylolisthesis surgery (decompression and
fusion) is not a cost-effective procedure when examined over a 2-year period.
These data highlight the need to better evaluate back pain patients with more
specific diagnostic procedures, such as evocative diskography, selective nerve
root blocks, foraminal epidural steroids, and facet and medial branch blocks.
The information obtained from these procedures in experienced hands
allows the surgeon to more selectively choose who might benefit from surgical intervention. Many of the pain generators can also be addressed earlier
in the disease process if surgery does not cause significant paradoxical effect
on the aging spine. In this chapter we outline a technique for performing
endoscopic medial, intermediate, and lateral branch rhizotomy arising from
the dorsal ramus, a sensory branch from the origin of the main spinal nerve,
that we have termed, dorsal endoscopic rhizotomy.
The endoscopic applications outlined in this chapter are therefore applicable to all painful conditions arising from the facet joint complex.
5
examining the data from the SPORT trial,
INDICATIONS AND CONTRAINDICATIONS
Endoscopic rhizotomy has been performed successfully, and remains effective at over 3-year follow-up in most patients in our pilot study. It is appropriate for the following conditions causing axial back pain.
Ideal Indications
Patients who will most likely benefit from selective endoscopic rhizotomy
include the following:
1. Axial back pain solely from arthropathy of the lumbar facet joints with-
out leg pain: e diagnostic imaging of these patients may present with
435
436
P A R T V I I I The Future of the Aging Spine
Prone
A
F IG UR E 6 5- 1a , 1 b, 1 c Ideal patient with single level facet arthrosis and chronic, non-debilitating axial back pain.
25 degree CAUD ANG
B
narrowing disc space, but the discogenic contribution to back pain is
thought to be a minor contributor. ese patients are usually not debilitated, but the patients’ pain significantly affects their activities of daily
living (Figure 65-1A-C).
2. Axial back pain mostly from facet arthrosis with very mild buttock and
thigh pain: Pain is approximately 90% in the back and 10% in the leg.
3. Subacute and chronic axial back pain following a posttraumatic injury to
the facet joints refractory to nonsurgical treatment.
4. Axial back pain from adjacent disc level of fusion demonstrating spondylosis and facet arthrosis causing pain without disc segment instability.
5. All of the previously mentioned patients should have more than 80%
pain relief after controlled diagnostic and therapeutic medial branch
block (MBB).
Relative Indications
Patients in the following categories should expect only partial relief of axial
back pain from dorsal ramus rhizotomy:
1. Axial back pain associated with mild buttock pain and leg pain: In general, back pain is about 50% to 80% and leg pain is 20% to 50%, with pain
coming from the facet as well as the disc.
2. Axial back pain from facet is 50% with leg pain 50% in general: Patients
received previous benefit from medial branch block, plus transforaminal
epidural block. e patient has a strong desire for relief of axial back pain
more permanently with a minimally invasive procedure, while intermittent sciatica is tolerable.
3. Patient has axial back pain, 40% to 50%, and leg pain, 50% to 60%, with
stenosis and instability indicated for surgical decompression and fusion,
but the patient elects a less invasive staged procedure or whose medical
condition does not allow for higher-risk surgical procedure. e patient
would be satisfied to have a decreased pain level and partially improve
the quality of life, in addition to reduced pain medication dose. ese
patients, indicated for fusion, should not have high expectation with dorsal endoscopic rhizotomy.
4. FBSS without pseudarthrosis and gross deformity presenting with axial
back pain only and responding well to MBB.
5. Patient associated with mild and stable spondylolisthesis, but presenting
with axial back pain of facet origin.
6. All of the previously mentioned categories of patients should have 50%
to 80% pain relief after MBB before dorsal endoscopic rhizotomy. is
group of patients should be very realistic about the anticipated pain
relief.
Patients with Poor Indications for Dorsal Ramus Rhizotomy
Patients with lumbosacral radiculopathy whose debilitating leg pain is
greater than back pain:
1. Multiple-level disc disease with confirmed severe concordant disco-
genic pain by evocative diskography, and minimal relief with medial
branch blocks
C
2. Significant motion segment instability or hypermobility
3. Pseudarthrosis following failed fusion
4. FBSS with more leg pain than back pain without known etiology
5. Patients with multiple debilitating painful conditions: severe multilevel
stenosis including foraminal stenosis associated with scoliosis without
good response to MBB
6. SI joint dysfunction
7. Severe osteoporosis, particularly with vertebral compression fracture
8. Severe depression, fibromyalgia, rheumatoid arthritis, and ankylosing
spondylitis as well as autoimmune diseases
9. Drug dependency
10. Psychosocial problems and pending litigation
11. No benefit from MBB
Patients initially benefiting from dorsal endoscopic rhizotomy, who have
recrudescence of some of their back pain, may have pain from progression
of vertical load forces shifting to the facets, such as progressive degenerative
scoliosis. These patients will have relief for 2 to 3 years before the effect of
rhizotomy fails. Spinal pain, however, may also come from multiple causes
and multiple anatomic structures in the spine. Certain conditions such as
anomalous nerves in the foramen may not be detectable using currently available technology, but may be visualized endoscopically. For a structure to be
implicated, it needs to be shown to be a source of pain from reliable diagnostic
techniques. Endoscopic examination of the foramen during foraminal surgery,
discussed in Chapter 64 on foraminal surgery for painful conditions of the
lumbar spine, identifies some of these nerve structures and anomalies. The
known structures responsible for pain in the spine include, but are not limited
to, the vertebral bodies, intervertebral discs, nerve roots, facet joints, ligaments,
muscles, and sacroiliac joints. Postlaminectomy syndrome (FBSS) following
operative procedures may affect these structures, and, except for recurrent disc
herniation or lateral recess stenosis, may not be surgically correctable. Contraindications for facet rhizotomy are pain syndromes not involving the facet
joint in some way. Neural blockade or nerve block therapy, however, is a validated procedure that, when performed properly, can implicate the facet joint
as responsible for spinal pain in up to 40% of patients with low back pain.
Patients with this condition usually have moderate to severe back pain that
does not have a strong radicular component. Pain is aggravated by hyperextension of the spine, and may present with tenderness to palpation at the level
of the suspected facet joint. Patient selection, therefore, depends more on the
patient’s response to proper administration of medial branch blocks rather
than facet injections, because the procedure targets the nerve innervating the
facet joint. Although x-ray, CT scan, and MRI findings of degenerative disc
disease, lumbar spondylosis, and facet arthrosis are helpful in concluding that
the facet is involved in axial back pain, the success of surgical ablation of the
branches of the dorsal ramus is dependent on clear interpretation and effective
resolution of axial back pain from medial branch blocks. Adding low-dose steroids (methylprednisolone [Depo-Medrol]) to longer-acting anesthetic agents
such as 0.5% bupivacaine provides long enough relief of axial back pain to help
make a clinical decision on the projected effectiveness of endoscopic rhizotomy.
Patient selection for the procedure for the prospective study begun in 2006
was indicated for patients receiving at least 50% back pain relief, but the pilot
study demonstrated endoscopic rhizotomy is most successful for those reporting 80% to 90% relief of their axial back pain following a medial branch block.
7
C H A P T E R 6 5 Dorsal Endoscopic Rhizotomy for Chronic Nondiscogenic Axial Low Back Pain
F IG UR E 6 5 -2 Yeung Endoscopic Spine System (YESS) rhizotomy
scope and cannula.
Contraindications are relative, since there may be limitations on the effects of
nerve denervation. In patients with multiple or nonspecific pain generators
such as myofascial pain syndrome, sacral iliac joint pain, or those with a soft
tissue source of pain where no nerve root pathology exists, have less satisfactory
results, even if there is a facet-component. Therefore, including these patients
who also have facet-mediated pain may serve as relative contraindications.
However, if the patient understands that the relief they get from facet rhizotomy is limited to the facet joint, then a satisfactory result can be obtained.
The effect of facet denervation in the pain management literature cites pain
relief lasting only 6 months to 1 year.
8,9
This is because current techniques of
radiofrequency lesioning may not be complete. Dorsal endoscopic rhizotomy,
however, was able to attain pain relief for this time frame more effectively,
because the surgeon is able to confirm adequate ablation of a visualized nerve
branch or the consistent location at least of the medial branch. Patients who
fail to get relief from radiofrequency ablation have been shown to get significantly more relief following dorsal endoscopic rhizotomy. These patients may
be offered dorsal endoscopic rhizotomy cautiously, because we assume that
failure may be due to poor patient selection rather that technique failure. An
ongoing continued review of A. Yeung’s 2006 prospective pilot study (presentation made at the International Society for Minimally Invasive spine surgery
in January 2007. Information not published.) reveals a majority of patients
still experiencing continued relief since the inception of the study (up to 3
years). Because of multiple pain sources in patients with an aging spine, results
of endoscopic rhizotomy are less predictable in patients who were only partially relieved of back pain obtained from the diagnostic blocks. Each injection
should be individually evaluated for clinical efficacy. In patients with only very
temporary pain relief, another trial block may be considered. Patients unable
to stop taking their anticoagulants for stroke, transient ischemic attacks, and
thrombophlebitis are at greater risk for surgical morbidity. These patients are
operated on with caution, risking complications from bleeding at the surgical
site. However, the ability to cauterize a small wound to control bleeding may
make the contraindication a relative one.
DESCRIPTION OF THE DEVICE
A YESS (Yeung Endoscopic Spine System) rhizotomy endoscope was
developed with the Richard Wolf Surgical Instrument Company (Vernon
Hills, Ill.) specifically for dorsal ramus rhizotomy. The length of the scope
is designed to allow the endoscope to rest on the fluid adapter with a focal
length that will keep the transverse process and the nerves in focus (Figure
65-2). The endoscope has two cannula configurations, a standard round can-
nula with a flat opening and a cannula with a beveled opening to allow flexible
curved bipolar radiofrequency electrodes and side-firing lasers to exit the wall
of the cannula for tissue coagulation and resection (Figure 65-3). Straight
and side-firing lasers, in addition to two types of radiofrequency electrodes,
are recommended because it is a more aggressive surgical tool for stripping
the periosteum and soft tissue envelope that may shield the medial branch.
BACKGROUND OF SCIENTIFIC TESTING AND CLINICAL OUTCOMES
Radiofrequency has been extensively used for ablation of the medial branch
in treating facet joint pain for years. It has been reported that most patients
only benefited from short term relief of pain.
rent axial pain from the same lesioned facet may be due to reinnervation
by regrowth of nerves. For this assumption, repeat radiofrequency for
8,9
It is also observed that recur-
437
F IG UR E 6 5 -3 Flexible Bipolar Radiofrequency Probes. Left: Probes
designed for small nerve transection. (1.5- to 2-mm gap). Right: Standard
Ellman Triggerflex (Elliquence, Inc.).
recurrence is common. Finding the exact location of the medial branch,
however, is not only essential to ablate the nerve, but in our study, the medial
branch was sometimes found to be buried in a periosteal tunnel up to several millimeters thick. Blind, even perfectly placed, thin wire electrodes
may not be able to adequately ablate the nerve. Efforts have been made to
improve the radiofrequency technique by needle position, making multiple
lesions and using larger needles.
(ATY) embarked on an endoscopic surgical technique in 2005 using the
FDA-approved Vertebris 3.1-mm spine endoscope spine system for foraminal lumbar surgery. In the YESS system, bipolar radiofrequency flex probe
and Ho:YAG laser are important surgical tools for tissue ablation and thermomodulation. It has been reported that percutaneous laser medial branch
rhizotomy provided better and longer-lasting results than radiofrequency
lesioning,
8,9
and this reasoning is confirmed by using the same tools in selective endoscopic rhizotomy. Derby and Lee
aggressive ablative process gives better results than traditional percutaneous
techniques utilizing two needle electrodes during lumbar facet rhizotomy
in an experimental model. The literature also supports multiple ablations
with radiofrequency because it provided better results than a single lesion. A
prospective study was initiated by the senior author in March 2006 before
Dr. Linqiu Zhou reported his work on cryotherapy for dorsal ramus syndrome at the 19th International Intradiscal Therapy Meeting in April 2006.
Dr Zhou was involved in the Chinese study of over 2630 patients that utilized a cryotherapy technique targeting the dorsal ramus to relieve pain from
chronic muscle spasm, and upper lumbar back pain. The paper presented by
Dr. Zhou and colleagues, titled “The Spinal Dorsal Ramus and Low Back
Pain,” presented evidence that anatomic dissections of the dorsal ramus at
L1 and L2 extended two to three segmental levels below L2.
A prospective, nonrandomized study was initiated by the senior author
to determine whether the dorsal ramus, particularly the medial branch,
could be visualized endoscopically, and whether endoscopic rhizotomy
of the medial branch and visualized intermediate and lateral branches of
the dorsal ramus would produce better results than conventional rhizotomy techniques. The pilot study of 50 consecutive patients was initiated
in March, 2006, and was first reported at the 25th International Jubilee
Course on Percutaneus Endoscopic Spine Surgery and Complementary
Techniques at Zurich, Switzerland in January, 2007.
were lumbar degenerative conditions that resulted in facet pain from the
aging spine or postoperative facet-mediated pain (Table 65-1). We primar-
ily targeted the medial branch in the osseous tunnel with an endoscope and
attempted to ablate it under visual control. This resulted in excellent axial
pain relief in the vast majority of patients receiving endoscopic rhizotomy.
There were no complications. When the nerve branch was traced to the
dorsal ramus, it resulted in fenestration of the intertransverse ligament,
bleeding, and painful feedback from the patient during the ablation process.
Twitching muscles could also be felt by the surgeon. Temporary ache and
mild dysesthesia were reported by the patients, but no patient was worse.
Ultimately, 90% (45/50) of the patients still had relief at 6 months followup. Only five patients had recurrence of their back pain at 6 months. Aggressive ablation of the dorsal ramus or inadvertent penetration of the probe and
cannula deep to the intertransverse ligament sometimes caused bleeding and
temporary dysesthesia, This led to the use of indigo carmine dye to help
guide the surgeon to stay dorsal to the ligament in pursuing the nerve. We
10
To continue this effort, the senior author
10
reported in 2006 that a more
11
6
Inclusion criteria
438
P A R T V I I I The Future of the Aging Spine
TA BL E 65 -1 Inclus ion Criteri a of Pilot S tudy on Sele ctive
Endo scop ic Rh izotomy
Pilot Study Inclusion Criteria: Endoscopic Medial Branch and Dorsal
Ramus Rhizotomy
Mri evidence of facet arthrosis
Failed or not satisfied with nonsurgical pain management
At least 50% relief with medial branch blocks
No psycho-social or litigation problems
No workman’s comp
Includes patients with increased back pain subsequent to discectomy
TA BL E 65 -2 Resul ts of Prospe ctive Non random ized Study
Prospective Non randomized Pilot Study
Method:
Endoscopic medial branch And D.R.Rhizotomy
50 consecutive patients
2-9 month follow-up
VAS
Oswestry
Preliminary Early Results
45/50 (90%) still had relief at 6 month follow-up and were satisfied
Ave VAS 6.2 to 2.5
Ave Oswestry 48 to 28
therefore conclude that ablation of the dorsal ramus is not needed, even if
potentially more effective in relieving back pain, because it may cause unacceptable unforeseen complications by ablation near the dorsal root ganglion.
VAS and Oswestry scores were tabulated. VAS decreased from 6.2 to 2.5
and Oswestry from 48 to 28; 90% of patients had continued improvement
at 6 months follow-up (Table 65-2). The extended study continues, and
recent review of patient data by an independent reviewer and co-author (Y.
Zheng) further confirmed the previous study results. In carefully selected
ideal patients, satisfactory results were achieved in more than 90% patients
without complications. These encouraging data and satisfactory feedback
from patients motivated the authors to introduce this new minimally invasive endoscopic surgical technique.
CLINICAL PRESENTATION AND EVALUATION
Patients who complain of chronic axial back pain are evaluated with x-rays and
MRI or CT scan. A history is taken to rule out nonfacet sources of chronic
back pain. After informed consent is discussed with the patient, the goals and
expected results of selective endoscopic rhizotomy are understood, the patient
is offered this surgery as an alternative to nonsurgical pain management or,
sometimes, traditional surgical management consisting of decompression and
stabilization.
OPERATIVE TECHNIQUE
Anesthesia
Surgery can be performed under local or monitored anesthetic care (MAC),
obviating the need for general anesthesia. Most patients are sedated with
fentanyl and midazolam (Versed), but some anesthesiologists choose to use
propofol since the procedure is short and the patient is comfortable after
the surgical site is anesthetized with 0.5% bupivacaine (Marcaine) with
epinephrine.
Its application potential in the elderly is virtually limitless, especially since
it allows for the outpatient and minimally invasive treatment of chronic back
pain currently managed with either large, open surgeries or strictly with pain
management and pain medications.
Position
The patient is placed prone with the lumbar spine placed on a kyphotic frame
with the back parallel to the floor. Reducing lumbar lordosis for the purpose of surgical access to the transverse process helps to prevent inadvertent
penetration of surgical instruments into the foramen where the irritation of
the dorsal root ganglion and exiting spinal nerve can cause surgical morbidity.
Procedure
The procedure begins with needles placed on the transverse process just lat-
eral to the facet in the muscle interval between the multifidus and longissimus muscle (Wiltse’s paramedian approach). Isovue 300, mixed with 10%
indigo carmine dye, is injected into the interval to help the surgeon identify
the tissue plane endoscopically. Indigo carmine dye is used to mark the tissue planes and the level of the transverse process dorsal to the intertransverse
ligament. At times dye can be seen leaking to the facet joint capsule or to the
foramen, at times even outlining the location of the dorsal ramus if there is
a breach of the foraminal ligament leading to the foramen. The endoscope
is then inserted through the cannula and docked on the transverse process
(Figure 65-4). The medial branch of the dorsal ramus is first targeted (Fig-
ure 65-5). It is not always visualized because the nerve is protected by a soft
tissue envelope. However, when the nerve is identified crossing the transverse
process, it is transected under direct vision, as is the lateral branch. A modification of the technique begins with wagging the blunt obturator to develop
the tissue plane between the multifidus and longissimus muscle. This facilitates visualization of the lateral branch of the dorsal ramus, cephalad to the
edge of the transverse process (Figure 65-6). If the nerve is not identified, all
the soft tissues are stripped to the periosteum of the transverse process adjacent to the lateral facet, especially to the cephalad edge of the transverse process. In the first 50 patients of the prospective study, the nerves at the base of
the transverse process were mainly targeted, while looking primarily for the
medial branch. The intermediate and lateral branch was targeted when visualized. With the wagging maneuver, the intermediate and lateral branch was
visualized more easily. After 100 patients, continued surgical experience and
greater surgeon experience allowed for more aggressive dissection along the
tissue plane between the multifidus and longissimus muscles to actively look
for multiple lateral branches to ablate, sometimes following the branches to the
dorsal ramus. Care, however, is taken to stay dorsal to the intertransverse ligament to avoid irritation of the exiting spinal nerve and the dorsal root ganglion
in the foramen. Our cadaver dissections provided even more anatomic information on the complexity of facet innervation, especially from L3 cephalad
(Figure 65-7). This finding, plus some anatomic dissections with demonstrat-
ing caudal connections of the dorsal ramus with segments below ( Figure 65-8),
provides evidence that rhizotomies of the dorsal ramus above the level of imaging involvement may have a role in the treatment of axial facet mediated pain.
We do not, however, recommend routine ablation of the dorsal ramus because
it is very benign to ablate the branches of the dorsal ramus at the involved
spinal segment, and the risk of neuroma and spinal nerve injury is lessened
significantly.
The medial branch of the dorsal ramus was more difficult to identify than
the lateral or intermediate branches because it may be buried in thick periosteum or capsular tissue, but ablation of soft tissue to cortical bone assured ablation of the medial branch. The Ho:YAG laser (Trimedyne, Inc., Santa Ana,
CA) was found to be the most effective surgical tool for ablation through thick
collagenous tissue. If the procedure is modified to develop the plane between
the multifidus and longissimus muscles, much like a dissection using Wiltse’s
approach to the transverse process for pedicle screw placement. It is easier to
visualize the intermediate and lateral branches. The literature contains illustrations of the anatomy of the dorsal ramus and its branches at the transverse
process (see Figure 65-4).
POSTOPERATIVE CARE
The patient is sent home if his insurance allows endoscopic rhizotomy as
an outpatient procedure; otherwise the surgery is performed in a hospital
and the patient is admitted for overnight observation until the patient opts
to go home. There is no postoperative treatment plan specific to rhizotomy. The patient is returned to his or her normal or desired activity level.
C H A P T E R 6 5 Dorsal Endoscopic Rhizotomy for Chronic Nondiscogenic Axial Low Back Pain
Technique review
Needle placement
439
Lat branch
Isovue 300 + 10% indigo carmine
Insert cannula Endoscopic rhizotomy
F IG UR E 6 5- 4 Selective endoscopic rhizotomy surgical technique.
ADVANTAGES AND DISADVANTAGES
A visualized nerve ablation is more effective than the traditional blind percutaneous technique. e ability to ablate the medial branch will eliminate facet
pain, and ablating the selected lateral branch that innervates the longissimus
muscle and lateral soft tissues helps to decrease paravertebral muscle spasm.
Because the lateral branches are multisegmental, ablation of the lateral branch
has met with no clinically adverse symptoms. With the procedure being a new
technique, the disadvantage may currently come from the limited availability of
surgeon training and surgical equipment.
COMPLICATIONS AND AVOIDANCE
Rarely, transient dysesthesia may result, especially when there was inadvertent penetration of the intertransverse ligament or if the patient felt
pain during the ablative procedure. Ablation of the lateral branch may
cause the muscles to twitch, but the patient should have no pain. Staying dorsal to the intertransverse ligament avoids the possibility of exiting and foraminal nerve injury. The use of indigo carmine dye helps the
Ablate lateral branch DR
surgeon stay dorsal to the foramen. Avoiding ablation of the dorsal ramus
may remove risk of neuroma formation or irritation of anomalous nerves
such as furcal nerves and autonomic nerves in the foramen described in
Chapter 64.
CONCLUSIONS AND DISCUSSION
Endoscopic ablation of the medial branches, along with a selected lateral
branch of the dorsal ramus, is effective in relief of chronic axial back pain
from facet joint and may decrease the need and consideration of fusion as a
surgical means of relieving chronic axial back pain (Figure 65-9, Box 65-1).
It is certainly more cost-effective in the short term compared to fusion. A
large-scale and long-term follow-up is needed to observe whether the technique can decrease the trend toward more fusion procedures in managing
axial back pain in the aging spine. Endoscopic rhizotomy offers a bridge for
treating many spinal ailments in patients who might not fare well with large
open surgeries yet need something more than conventional pain management. To understand selective endoscopic rhizotomy, the detailed surgical
anatomy of the dorsal lumbar rami and its significance for dorsal rhizotomy
is reviewed.
440
P A R T V I I I The Future of the Aging Spine
Dorsal
ramus
Medial
branch
Lateral
branch
• The facet is innervated by
the medial branch of the
m
a
F IG UR E 6 5- 5 Anatomy of the medial branch of the dorsal ramus.
TP
dorsal ramus at its own level
and to the level below.
• Traditional denervation
ablates only the medial
branch in the osseous tunnel.
• Lateral branch to dorsal
column may contribute to
chronic back pain.
–Longissimus muscle
–Soft tissue lateral to multifidus
TP
Lateral branches
Medial branch stripped off transverse process
F IG UR E 6 5- 6 Location of the lateral branch of the dorsal ramus in relation to the transverse process.
F IG UR E 6 5 - 7 Cadaver dissection of the dorsal ramus and its branches in relation
to the transverse process.
Dorsal ramus ventral to
intertransverse ligament
C H A P T E R 6 5 Dorsal Endoscopic Rhizotomy for Chronic Nondiscogenic Axial Low Back Pain
F IG UR E 6 5 -8 The dorsal ramus is shown to connect through the a
plexus via the gray communicans that connects with nerves that innervate the
disc, then also sends branches to one or two segments caudally. This explains
how discogenic pain may also cause axial back pain.
mp
mb
mal
ap
441
Box 65-1 ENDOSCOPIC RHIZOTOMY
Endoscopic rhizotomy provides higher success than radiofrequency lesioning
with traditional catheter.
Endoscopic rhizotomy targets lateral branch innervation from dorsal ramus to
provide greater pain relief.
Patients who failed RFL have had successful results with endoscopic rhizo-
tomy.
e effect may be even more lasting when laser rhizotomy is incorporated for
lesioning.
in the intervertebral foramen. After leaving the spinal canal just outside
the foramen, the spinal nerve divides into a larger ventral ramus innervating the lower extremities and a smaller dorsal ramus innervating the
zygapophyseal joint, back muscles, and ligaments.
L1 to L4 Dorsal Rami
Bogduk described the lumbar dorsal rami in detail from his anatomical dissection of cadavers.
almost a right angle to the spinal nerve. The main stem is only about 5 mm
long. It runs dorsocaudally through the intertransverse space, deep to the
intertransversarii mediales. They are divided into three branches: medial,
lateral, and intermediate.
The medial branch (MB) passes dorsally and caudally toward the
superior border of the root of the subadjacent transverse process. From
there it continues dorsally and caudally lying inside the groove formed
by the junction of the root of the transverse process with the base of the
superior articular process. In this region, the nerve is bound to the periosteum by a layer of connective tissue, which coats the facet joint and
transverse process. The MB continuously courses caudally. At the caudal border of the facet joint, the MB turns medially through a groove
between the mamillary process and accessory process, covered and held by
the mamillo-accessory ligament. After passing this groove, the MB runs
medially and caudally across the vertebral lamina. It lies deep to the multifidus and also sends off articular branches to the facet joint and interspinous process. MB sends off proximal zygapophysial nerve (PZN) and
distal zygapophyseal nerve (DZN). PZN innervates the cephalaic facet
joint from its caudal side upward, and DZN innervates the caudal facet
joint from cephalad side downward. Ultimately MB enters the multifidus
muscle via its deep surface.
The lateral branch (LB) crosses the subadjacent transverse process and
courses laterally, caudally, the and dorsally through the iliocostalis lumborum. The L1-L3 branches pierce the dorsal layer of thoracolumbar fascia
and become cutaneous. L3 LB is bound down to the iliac crest. L4 LB
remains entirely intramuscular.
The intermediate branch (IMB) runs dorsally and caudally distributing
to the longissimus thoracis muscle. IMB also has intersegmental communicating loops.
10
(Bogduk 1980) The L1 to L4 dorsal rami project at
Lateral branch of dorsal ramus
F IG UR E 6 5- 9 Lateral branch of dorsal ramus.
Anatomy of the Lumbar Dorsal Ramus
There are five pairs of lumbar spinal nerves (Figure 65-10). Centrally, the
spinal nerve consists of ventral and dorsal roots. The ventral root comes
from the anterior horn of the spinal cord and the dorsal root comes from
the posterior horn of the spinal cord. The dorsal root has a dorsal ganglion after leaving the spinal cord and before joining the ventral root.
The ganglion contains the cell bodies of the sensory fibers in the dorsal root. The ganglion lies within the dural sleeve of the nerve root and
occupies the upper and medial part of the intervertebral foramen. The
ventral and dorsal roots join together laterally become the spinal nerve
L5 Dorsal Ramus
The L5 dorsal ramus is longer than the L1-L4 dorsal rami. It courses the
superior border of the ala of the sacrum, lying in the groove formed by
the junction of the ala and the superior articular process of the sacrum. It
divides into medial and intermediate branches, lacking a lateral branch.
The medial branch curves medially around the caudal aspect of the lumbosacral facet joint and ends in the multifidus muscles. The intermediate
branch innervates the longissimus thoracis and communicates with the
S1 dorsal ramus. Ablation of the branches of the dorsal ramus, with
its complex innervation, may provide axial back pain relief beyond the
level surgically ablated. Care is taken when the dorsal ramus is ablated
because partial ablation of a large nerve may result in dysesthesia or the
formation of a neuroma. No patient, however, considered themselves as
worse, even if the procedure did not provide the anticipated or desired
pain relief.
442
2
Spinal nerve
1
6
3
Gray ramus
communicans
P A R T V I I I The Future of the Aging Spine
Spinal
ganglion
Cell of Dogiel
White ramus
communicans
Sympathetic
ganglion
2
6
7
Posterior
nerve root
Sympathetic cord
1
3
4
5
Anterior
nerve root
Sympathetic
ganglion
F IG UR E 6 5 -1 0 Connections with the spinal nerves.
Communications are established between the sympathetic and
spinal nerves through what are known as the gray and white rami
communicantes. The gray rami convey sympathetic fibers into the
spinal nerves and the white rami transmit spinal fibers into the
sympathetic. Each spinal nerve receives a gray ramus communicans from the sympathetic trunk, but white rami are not supplied
by all the spinal nerves. The gray ramus commuincans connects
the spinal nerve with sympathetic and autonomic nerves in a complex innervation of the disc and posterior elements.. Chronic back
pain from an aging spine most likely involves not just the spinal
nerve, but its autonomic connections.
4
References
1. J.N. Katz, Lumbar disc disorders and low-back pain: socioeconomic factors and consequences, J. Bone Joint. Surg. Am. 88 (Suppl 2) (2006) 21–24.
2. R.G. Hazard, Failed back surgery syndrome: surgical and nonsurgical approaches, Clin.
Orthop. Relat. Res. 443 (2006) 228–232.
3. B.I. Martin, S.K. Mirza, B.A. Comstock, et al., Reoperation rates following lumbar spine
surgery and the influence of spinal fusion procedures, Spine 32 (3) (2007) 382–387.
4. B.K. Weir, G.A. Jacobs, Reoperation rate following lumbar discectomy. An analysis of 662
lumbar discectomies, Spine 5 (4) (1980) 366–370.
5. J.N. Weinstein, T.D. Tosteson, J.D. Lurie, Tosteson An, B. Hanscom, J.S. Skinner, et al.,
Surgical vs nonoperative treatment for lumbar disc herniation: the Spine Patient Outcomes
Research Trial (SPORT): a randomized trial, JAMA 296 (2006) 2441–2450.
6. A.T. Yeung, Endoscopic medial branch and dorsal ramus rhizotomy for chronic axial back
pain: a pilot study, International 25th Jubilee Course on Percutaneus Endoscopic Spine Surgery and Complementary Techniques. Zurich, Switzerland. January 24-25, 2007.
7
7. S. Datta, M. Lee, F.J. Falco, D.A. Bryce, S.M. Hayek, Systematic assessment of diagnostic
accuracy and therapeutic utility of lumbar facet joint interventions, Pain Physician. 12 (2)
(2009) 437–460.
8. K. Iwatsuki, T. Yoshimine, K. Awazu, Alternative denervation using laser irradiation in lumbar facet syndrome, Lasers Surg. Med. 39 (3) (2007) 225–229.
9. Kantha Sri. Lumbar facet joint denervation by laser thermo-coagulation. 18th International
Intradiscal Therapy Society Meeting May 25-28, 2005, San Diego, CA.
10. R . Derby, C.H. Lee, The efficacy of a two needle electrode technique in percutaneous radiofrequency rhizotomy: An investigational laboratory study in an animal model, Pain Physician. 9 (3) (2006) 207–213.
11. Linqiu Zhou, Carson D. Schneck, Zhenhai Shao. The spinal dorsal ramus and low back
pain. Presented at the 19th Annual Meeting of International Intradiscal Therapy Society.
Phoenix, AZ. Apr. 5-9, 2006.
12. N. Bogduk, A.S. Wilson, W. Tynan, The human lumbar dorsal rami, J. Anat. 134 (1982)
383–397.
Economics of Spine Care
Stephen H. Hochschuler and Donna D. Ohnmeiss
66
INTRODUCTION
Health care has changed much in recent years, and will likely continue to
do so. While some amazing advancements have been made in fields ranging from diagnostic imaging to new pharmaceuticals, as well as new surgical interventions, numerous challenges have arisen with respect to cost
and access. Regardless of the economic and political discussions of health
care, there is certainty that amid the changing current climate, the population is aging. The first of the baby boomers are entering their 60s and will
soon become part of the Medicare population. This will greatly increase the
number of older patients who will expect high-quality care. In this chapter,
the authors will provide an overview of the economics affecting health care,
current challenges, and how these topics fit into providing spine care to an
aging population.
OVERVIEW OF THE ECONOMY AND HEALTHCARE
The year 2008 ended with great economic changes and challenges to be
addressed by the incoming Obama administration in 2009. The biggest names
in the financial world, such as Lehman Brothers, Merrill Lynch, Bear Stearns,
Wells Fargo, AIG, and Citibank were plummeting into ruin. Icons of American industry such as GM, Ford, Chrysler, and others such as Circuit City, were
facing complete failure. These financial problems swept the globe in a wave of
uncertainty. Many turned to the federal government for bailout support. The
government chose an avenue of giving large companies billions of dollars in
bailouts and stimulus packages to try to avert a total meltdown of the economy.
It is proposed that saving these large businesses as well as creating jobs through
highway improvement and other shovel-ready projects will increase confidence
in the financial system and let people feel confident enough to spend money
to fuel the economic recovery. This is a somewhat confusing issue, however,
because a large part of the problem was based on too much credit without
enough savings and now, in the short term, the government hopes to change
the present course of recession with more spending. How well this course of
action works will not be determined for several years. On an individual level,
millions have lost their savings for retirement, and millions have lost their jobs,
leading to the loss of homes and even access to health insurance.
Health care represents some of the best and worst in the United States.
Great advances continue to be made in imaging and other diagnostic procedures, implants are continually patented and developed, and widespread
use of the Internet has produced a much more educated patient than in
years ago. However, problems with our health care system include the many
uninsured (due to lack of availability, lack of affordability, and persons opting to not pay for insurance although they can afford it), workers becoming
uninsured through layoffs or illness, workers with insurance having requests
for treatment denied by insurers, escalating costs, decreasing physician reimbursements, lack of access, frivolous medical-related lawsuits, unnecessary
procedures being prescribed, and inadequate quality assessment and feedback systems. With respect to costs, new terms, such as “medical foreclosure”
and “medical bankruptcy” have been added to our vocabulary in recent years.
The amount of resources consumed by health care continues to grow
rapidly, well ahead of the pace of inflation. In 2007, the estimated spending was $2.2 trillion and was expected to rise to $4.3 trillion by 2017.
At that time, it is estimated that health care spending will represent 19.5% of
the gross domestic product. The paradox lies in what Americans are getting
for their health care dollars. While the United States spends more on health
care than any other country, in 2004, it ranked twenty-third in life expectancy for men and twenty-fifth for women.
cans between the ages of 18 and 64 years do not have health insurance.
Among the working population in this age group, the average premium for
workplace-based health insurance rose more than 115% from 1999 to 2008,
burdening both employees and employers.
group is insurance being linked to employment. If someone loses his or her
job, he also loses his access to affordable insurance coverage. Many in this
group also feel that even if they have insurance, once a health problem arises,
they are often denied coverage for treatment.
On the other hand, insurers struggle with escalating costs charged for
newly developed drugs and implants, as well as the potential for add-on
technologies to be used during an operation or a course of treatment. They
also are accountable for meeting the demands of their investors to consistently produce a competitive profit margin. The Internet has helped greatly
in educating patients about various health-related conditions and potential
treatment options. However, the Internet, along with direct-to-consumer
marketing, has produced patients with greater demands for their health care
providers to prescribe particular medications and perform various procedures that the consumers may not otherwise ask for.
The concept of competitive effectiveness is at present (April 2009) a
topic being addressed in Washington as a solution for rising health care
costs. Although on the surface the concept is irrefutable, there is much
concern that when Washington makes these decisions without significant
physician and patient input and then adds cost-effectiveness, health care
rationing, such as is seen in Canada and England, might well result.
One possible scenario to address the 47 million uninsured as well as
revamping health care insurance might be a government-sponsored program
to subsidize health savings accounts (HSAs). This would make the patient the
source of purchasing health care and, just as with purchasing a car, the consumer would purchase what is needed based on comparative analysis of different procedures, providers, and implants. Pay-for-performance, which insurers
are proposing, would be carried out in HSA scenario to the individual and not
capricious treatment decisions made by the insurance companies. In addition,
such a system would afford patients the much-sought after portability.
Other areas of health care have changed drastically during the past several years. There is much less trust in the FDA’s ability to adequately monitor the safety of food, medications, and medical devices; use and promotion
of products off-label has come to merit investigation by the FBI and other
federal agencies; concern has arisen over the financial relationships between
industry and physicians; and, for many years, physicians have felt obligated to
practice defensive medicine to help ward off exorbitant malpractice lawsuits.
2
Approximately 20% of Ameri-
4
One of the problems for this
OVERVIEW OF SPINE CARE
Spine care is far from immune from the challenges health care is facing.
Guyer described this paradox in spine care with the excitement of numer-
1
ous new devices and treatments contrasted with financial challenges.
5
As
443
3
444
P A R T V I I I The Future of the Aging Spine
previously mentioned, there is a problem with the physician–medical manufacturer relationship. As the health care market became more competitive,
spine companies looked to new ways of improving and marketing products.
At the same time, declining reimbursements led physicians to look for other
avenues of revenue. This led to companies teaming with surgeon- consultants
to design new implants. The companies provide the engineering expertise
and the surgeons provide expertise in knowing what types of devices are
needed and what designs are most feasible for use. Unfortunately, some
companies and surgeons elected to abuse this productive collaboration and
instead turn it into an unethical practice of payment for use of certain products and payments for services that were never rendered. This has resulted in
a declining interaction between industry and physicians, reduced funding to
support research and education, public disclosure of financial relationships
and investigations, and arrests for inappropriate payments to physicians
as well as for off-label promotion by physicians and corporate employees.
Groups such as Advamed have emerged, and continue to refine guidelines
for interaction between industry and physicians. Others have suggested banning any relationship or support from industry to physicians or organizations. This drastic a measure would undoubtedly have severely detrimental
effects on research as well as new product development.
Although back pain is a multibillion-dollar problem annually in the
United States, there is surprisingly little solicitation for federal grants to
support research in this area. Ultimately, without corporate support, back
pain research and education would be severely limited, a step that cannot be
beneficial by any measure.
BACK PAIN IN A CHANGING POPULATION
The increasing percentage of the population that is over 60 years will impact
spine care. Much of the focus in the past has been on younger patients, in
whom the majority of back pain has been related to herniated discs and
painful disc degeneration. In many publications dealing with the treatment
of painful spinal conditions, the mean age has been in the 40s. With the
influx of baby boomers into the Medicare population, the dominant needs
in spine care will likely shift. Their needs will be oriented toward stenosis, osteoporotic spinal fractures, and degenerative scoliosis. One should
remember some of the characteristics of this generation as well. They generally want to be active and demand quality service. A few steps have already
been taken toward designing surgical interventions for older patients. In
recent years, implants such as interspinous devices have been introduced
and they continue to evolve. Osteoporotic fractures are now treated with
procedures such as kyphoplasty and vertebroplasty. It is likely that we will
continue to see increased focus on the development of therapies for those 50
to 60 years old and older that are often minimally invasive and focused on
return to activity.
There has been great enthusiasm for the movement away from traditional spinal fusion toward motion-preserving technologies. Singh et al projected that by 2010, 47.9% of the spine market will be arthroplasty devices.
This was estimated to be approximately $2.18 billion.
It is to be noted that the medical spine market does not necessarily
follow the traditional pattern of economics, with respect to the pricing of
devices varying with supply and demand. One example of this was described
by Lieberman who applied it to pedicle screws.
the pedicle screw and rod systems changed little from 1900 to 2000, their
prices rose from $135 to $160 to $225 to $700. The continual increase was
not attributed to increasing development or manufacturing costs, but rather
to what the market would bear. As noted by Hochschuler on this topic, with
many new technology items such as computers, time and competition drive
the prices lower if there are no significant enhancements of the product.
However, what was seen with pedicle screws is that the number of companies offering screw and rod systems increased through the years, but the
prices increased rather than decreased.
One item that is often discussed is the cost-effectiveness of spinal surgery. Unfortunately, there have been very few studies investigating this topic.
However, in the few studies that do exist, spine surgery has been found
to be in line with other commonly accepted surgeries. One of the strategies employed to address the cost-effectiveness of spinal surgery has been
to compare various procedures to well-accepted surgical procedures. Polly
et al reviewed the SF-36 results reported in 11 different fusion studies and
7
While the basic design of
compared them, based on cost per unit of change in the physical component scores of the SF-36, to results reported from total hip replacement,
total knee replacement, and carotid artery bypass surgery.
8
Their analysis
found that fusion was more cost-effective than bypass surgery, similar to
knee replacement, and less cost-effective than hip replacement. However, it
should be noted that 9 of the 11 fusion studies included in the analysis were
based on IDE trials. This may have somewhat skewed the results, due to the
rigorous patient selection criteria employed in most trials. Also, the surgical
protocol in such studies does not allow the use of multiple bone graft types,
off-label use of bone graft or implants, or the decision to use additional
items such as anterior lumbar plates, “door stop” screws with anterior graft
or cages, or other items. This restriction of implants may have lowered the
costs of fusion in the IDE trials compared to typical use patterns. Another
study investigated the cost-effectiveness of spinal decompression by comparing it to total hip replacement.
8
The authors found decompression to be
50% more cost-effective than hip replacement. Some of this may be attributable to the lack of implants used in spinal decompression.
As advances have been made in spinal surgery, one item of debate has
been the use of bone morphogenic protein (BMP) to enhance spinal fusion.
While this material has been attributed to producing a high fusion rate, its
cost has been the source of concern. One study analyzing this issue found
that the operative cost of using BMP was greater; however, over time BMP
became cost-neutral due to the reduced costs of future care associated with
iliac crest donor site pain and subsequent costs related to a higher rate of
pseudarthrosis in fusion surgeries performed not using BMP.
As interest in spine surgery has moved away from fusion to motionpreserving technologies, the concern about costs has moved into this arena
as well. One such intervention is total disc replacement (TDR). While this
technology holds the promise of reducing pain and allowing motion of the
operated segment, questions about the costs related to its use have arisen.
Guyer et al reported the results of a cost-effectiveness model comparing
the operative costs and treatment costs through a 24-month postoperative
10
period.
TDR was compared to ALIF with BMP and cages, ALIF with
iliac crest autograft, and PLIF using autograft and pedicle screw fixation.
The cost model suggests that operative costs, as well as costs throughout the
follow-up, were significantly less in the TDR group compared to each of the
fusion procedures. Also comparing the costs of TDR to fusion, Patel et al
reviewed hospital costs related to single-level TLIF, circumferential fusion,
ALIF alone, and TDR.
11
They found the total hospital costs of TDR were
significantly less than any of the three fusion groups. The cost of TDR was
similar to TLIF and ALIF, if the cost associated with using BMP in these
fusion procedures was not included. Levin et al also reported that singlelevel TDR was related to significantly lower hospital charges compared to
circumferential fusion.12 However, they found no significant difference in
the charges for two-level procedures.
The evaluation of TDR in Switzerland is perhaps a predictor of the
future on a global basis for the evaluation of new spinal implants. The Swiss
6
government required a national registry of all TDR procedures. From the
data collected, a decision would be made concerning the reimbursement
for use of the device. The early data from that registry have recently been
published.
13
The authors referred to this process as following the “health
technology assessment” principle of ‘‘coverage with evidence development.”
Prospective data for 427 patients were analyzed. Pain scores, quality of
life, and medication usage all improved significantly. The rate of complications occurring with the surgery and/or initial hospital stay was 3.9% for
single-level cases and 8.6% for two-level procedures. Rehospitalization and
revisions occurred in 3.1% of single-level cases and 1.4% of two-level cases.
The authors concluded that TDR appeared to be a relatively safe and effec-
6
tive procedure, at least in the short-term. But what may be more important
about this study is that it creates a comprehensive model to evaluate new
technologies. The use of such registries may help to address many concerns
that arise in IDE trials and individual studies with respect to how generalizable are study results to broad-scale use. It also provides the collection of
data for a large number of subjects so that the occurrence of complications
can be identified more quickly than in relatively small studies.
The lumbar spine has generally received much more attention than the
cervical region. However, there are many patients with significant neck pain
and related cost of treatment. With the aging population, the number of cervical problems related to degenerative spinal conditions is likely to increase.
9