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C H A P T E R 3 2 Tumors of the Cervical Spine
F IG UR E 3 2 - 3 Sagittal and axial MR images of the cervical spine. Left and Center, Sagittal T2-weighted images demonstrating a chordoma involving the
C-2, C-3, and C-4 vertebral bodies with retropharyngeal and epidural extension. Right, Axial contrast T1-weighted image revealing an extensive soft-tissue mass with
encasement of the right VA and displacement of the posterior pharyngeal wall. (From J Neurosurg Spine 2:199-205, 2005.)
195
*
*
*
*
*
*
*
*
*
A
F IG UR E 3 2- 4 Serial intraoperative photographs showing the steps involved in the initial (posterior) stage of the surgery. A, Close-up view of the occipitocer-
vical region showing partial C1 and bilateral C2–4 laminectomies and facetectomies, epidural tumor on the right (arrow), left C2, C3, and C4 nerve roots (asterisks),
and skeletonized VA on the left. Also see the proximal portion of the right VA as it enters the tumor. B, Dorsal view of the thecal sac after placement of Silastic sheet
between ventral dura and the tumor mass. The right C2, C3, and C4 nerve roots have been transected. (From J Neurosurg Spine 2:199-205, 2005.)
plane of dissection was created on the right lateral side of the tumor, and
a Silastic sheet was placed between the tumor and the ventral thecal sac
to protect the neural structures during the subsequent anterior procedure.
Occipito-cervicothoracic fixation was performed. At this point, prior to the
second stage, MRA was performed to evaluate patency of the left VA to
ensure safe sacrifice of the right VA for tumor resection.
Next, the patient was positioned in the supine position. The second
stage, an anterior approach, was designed to complete the en bloc resection
and reconstruct and stabilize the ventral spinal defect. A right lateral neck
dissection accompanied by a transmandibular, circumglossal, retropharyngeal exposure was performed. Subsequently, a C4-5 discectomy was performed, the uncovertebral joints were drilled, and the posterior longitudinal
ligament was resected for visualization of the ventral dura. Soft tissue free of
tumor was freed from the anterior arch of C1.
B
On the left, the longus colli insertion on the transverse process of C2-4
was released to allow the transverse process to be drilled away, completing
the circumferential exposure of the left VA from C2-5. The surgical margin
on the left was thus freed from all structures. On the right, the longus colli
muscles were mobilized above and below the tumor and the VA was dissected above C2 and below C4 so as not to violate the tumor. Additional
dissection was performed around the lateral aspect of the tumor, medial to
the carotid sheath, until this met with the dissection plane from the posterior approach. Temporary aneurysm clips were placed on the right VA and
SSEPs were noted to remain stable for 30 minutes. The vessel was ligated
and transected at both ends beyond the tumor, freeing the specimen along
the right lateral aspect. Finally, a high-speed drill was used to cut across the
base of the dens, and rongeurs were used to resect the ligamentous complex
behind the dens. This established a superior margin for the resection. The
196
P A R T I V Surgical Treatment Modalities: Cervical Spine
Uvula
Basilar a.
oris m.
Orbicularis
Sublingual
Posterior wall
of pharynx
tonsil
Palatine
Masseter m.
gland
Inferior
alveolar n.
Parotid gland
Facial a. and v.
Orbicularis oris
m. depressor
labis inferioris m.
depressor angult
oris m., mentalis
Vagus n.
Hypoglossal n.
Longus capitis m.
Rectus capitis ant. m.
m.
Thyrohyoid membrane
Submandibular gland
Hyoid bone
Mylohyoid m. (cut)
Digastric m.
Lingual n.
Int. jugular v.
Vertebral a. (cut)
Common carotid a.
Sternocleidormastoid m.
Tendered
synmesh
cage with
bone grafts
C4 spinal nerve root
Superior laryngeal
vein, artery, and nerve
Spinal dura
Synmesh cage
Thyroid gland
with bone grafts
Vertebral a.
Dens of axis
C1
of atlas
Cruciform ligament
right side
a. ligated and
divided on the
Right vertebral
divided
ligated and
Right C2, C3,
C4 nerve roots
C5
C6
F IG UR E 3 2 -5 Final hardware construct with placement of anterior cage. Upper Left, Intraoperative photograph showing the tricortical C1 and bicortical C5 screws. Lower Left, Detailed illustration of the final
construct. The cage functions as a strut and plating device. Center, Artist’s depiction showing the complete exposure with transmandibular access and tailored cage reconstruction in situ. Right, Postoperative axial CT
images with bone windows and sagittal reconstructed images revealing the final hardware position. (From J Neurosurg Spine 2:199-205, 2005.)
C H A P T E R 3 2 Tumors of the Cervical Spine
197
entire tumor mass, including the C2-4 vertebral bodies, the right VA segment, and the right C2-4 nerve roots were removed en bloc, but the resection was marginal at the dura.
A fibular allograft was then cut to size and fashioned to form a sharp
spike that could be embedded into the residual dens. The inferior end of
the graft rested firmly against the superior endplate of the first remaining
vertebra. A cervical plate was then fashioned to C1 and the most superior
remaining vertebra (C5) The screws fixing the plate superiorly were placed
with tricortical purchase, penetrating the anterior arch of C1 and engaging
the residual dens. The posterior pharyngeal nerve was evaluated to determine if it is still intact (if it is not, a free flap should be placed from an external location that has remained prepped during the surgery).
The patient required several weeks of ventilatory support and needed a
gastrostomy tube for difficulties with swallowing. Common complications
after resection of cervical primary malignant tumors include failure of stabilization, swallowing difficulties, hoarseness, Horner syndrome, and hypoglossal injury; often tracheostomy and gastrostomy tubes are required after
surgery. At a year from surgery, the patient is fully ambulatory, is able to swallow a regular diet, had his tracheostomy and gastrostomy tubes removed, his
spinal construct remains stable, and he has no clinical or radiologic evidence
of tumor recurrence. Radiation therapy has not been administered.
CONCLUSIONS
In this chapter, we describe the demographics, presentation, physical exam,
imaging, surgical planning and techniques including decompression and
spine stabilization, postoperative management, and adjuvant treatment of
tumors of the cervical spine. We describe tumors of the intramedullary,
intradural-extramedullary, and extradural regions with a specific emphasis on more common cervical spine tumors found in adults, including
ependymomas, schwannomas, metastases, and chordomas. In summary,
the majority of these tumors are ideally managed with complete surgical
decompression.
References
1. Z. Cohen, D. Fourney, R. Marco, L. Rhines, Z. Gokaslan, Total cervical spondylectomy for
primary osteogenic sarcoma, J. Neurosurg. Spine 97 (2002) 386–392.
2. O. Gottfried, W. Gluf, Quinones-Hinojosa, Kan P, Schmidt M: Spinal meningiomas: surgical
management and outcome, Neurosurg. Focus 14 (2003) 1–7.
3. O. Gottfried, M. Binning, M. Schmidt, Surgical approaches to spinal schwannomas, Contemp.
Neurosurg. 27 (2005) 1–8.
4. F. Hanbali, D. Fourney, E. Marmor, D. Suki, L. Rhines, J. Weinberg, I. McCutcheon, I. Suk, Z.
Gokaslan, Spinal cord ependymoma: radical surgical resection and outcome, Neurosurgery 51
(2002) 1162–1174.
5. M. McGirt, I. Goldstein, K. Chaichana, M. Tobias, K. Kothbauer, G. Jallo, Extent of surgical
resection of malignant astrocytomas of the spinal cord: outcome analysis of 35 patients,
Neurosurgery 63 (2008) 55–60.
6. R . Patchell, P. Tibbs, W. Regine, R. Payne, S. Saris, R. Kryscio, M. Mohiuddin, B. Young,
Direct decompressive surgical resection in the treatment of spinal cord compression caused by
metastatic cancer: a randomized trial, Lancet 366 (2005) 643–648.
7. L. Rhines, D. Fourney, A. Siadati, I. Suk, Z. Gokaslan, En bloc resection of multilevel cervical
chordoma with C-2 involvement, J. Neurosurg. Spine 2 (2005) 199–205.
8. D. Sciubba, J. Chi, L. Rhines, Z. Gokaslan, Chordoma of the spinal column, Neurosurg. Clin.
N. Am. 19 (2008) 5–15.
9. F. Vincent, M. Fehlings, Spinal column tumors, in: M. Bernstein, M. Berger (Eds.), Neurooncology: the essentials, ed 2, Thieme Medical Publishers, New York, 2008.
Role of Minimally Invasive Cervical
Spine Surgery in the Aging Spine
Woo-Kyung Kim
33
k e y p o i n t s
e anatomic and pathophysiologic changes of the aging spine are discussed.
Techniques of various minimally invasive surgical procedures in the cervical
spine include anterior cervical microforaminotomy, percutaneous cervical
discectomy, microendoscopic discectomy, and percutaneous cervical
nucleoplasty.
e controversies of current minimally invasive surgical procedures are
presented.
INTRODUCTION
The aging of the population in industrialized nations appears to be an
inevitable situation. It does not simply mean an increase in life expectancy
owing to the improvement of medical science and health care, but additionally a significant decrease in birth rates has led to this situation. Back and
neck pain are most frequently occurred presentations of older people, and
the unique nature of the spine makes those problems highly complex to
evaluate and to manage. The spine is a very specific anatomic and functional unit. The findings of radiological degenerative changes of the cervical
spine in aging population are common. By the fourth decade of life, 30%
of asymptomatic subjects show degenerative changes of the intervertebral
discs, whereas by the seventh decade, up to 90% have developed degenerative alterations.
features in the light of the clinical presentation. If symptoms and findings
are not correlated, the presence of a different pathology should be suspected,
and appropriate evaluations are required. In order to assess the spine unit
of patients (clinical, radiological; and laboratory findings; neurophysiology, etc.), cooperation between the orthopedic surgeon, the neurosurgeon,
and the neurologisted is needed. Based on the present illness and physical
examinations, a proper neurological workup should be performed. In addition to the neurological assessment, additional laboratory evaluations and
other studies may be helpful in the differential diagnosis, including electromyography (EMG), electroneurography (ENG), sensory evoked potentials
(SEP), and motor evoked potentials (MEP).
The aging of the spine induces considerable alterations in anatomical
structures: discs, facet joints, ligaments, muscles, and bones. The degeneration of some of these structures can be responsible for the injury to the
neural structures by herniated disc, spinal stenosis, and other degenerative
disease.
Although various surgical treatments for spinal disorders have been
proposed for years, the current concept in the evolution of all spinal surgical procedure is mostly concerned with minimally invasive techniques. The
advantages of minimally invasive procedures include less postoperative pain,
shorter hospital stays with faster recovery, and decreased surgical morbidity,
mortality, and long-term sequelae. These benefits are the result of reduced
damage to surrounding spinal structures.
1,2
Thus, it is always important to interpret such radiological
1
198
BASIC SCIENCE
As a flexible, multisegmental column, the functional role of the spine is to
provide stabilization and upright position. The spine is composed of a static,
changeless component, the vertebral bodies, and an elastic mobile component,
the three joint complexes, consisting of the intervertebral disc and the two
posterior facet joints. As mentioned earlier, the aging spine experiences considerable changes in anatomy (the structural components, biomechanics, etc.).
The quantity of water present in the nucleus pulposus (contains a high
proportion of hydrophilic glycosaminoglycans) decreases and both spinal
height and the cushioning effect are reduced with aging. Gaps and fissures
may develop in the discs, and with the time they may become desiccated and
even ossified. As the disc height decreases, there may be a buckling of both
anterior and posterior longitudinal ligaments. The buckling posterior ligaments may project into the spinal canal, reducing the space available for the
spinal cord. Bony osteophytes may develop in the region of the vertebral bodies; endplate osteophytes may expand across the disc spaces and merge with
osteophytes of adjacent vertebrae to form bridging osteophytes. If the osteophytes involve posterior endplates, they may protrude into the spinal canal,
compressing the dural sac. People with congenitally narrowed spinal canals
have greater risk for spinal cord compression as a result of these changes.
Large bridging osteophytes on the anterior endplates may lead to severe
problems in gastrointestinal, respiratory, or vascular systems. The size of the
neural foramen, which the spinal nerves pass through, may be decreased both
with the loss of spinal length and ossification and hypertrophy of these soft
tissues around the vertebral column. Such age-related changes demonstrate
the symptomatology in most patients presenting for cervical spine surgery.
2
1,2
SURGICAL INDICATIONS AND PREPARATION
The indications for surgery include (1) persistent or recurrent upper
extremity pain or numbness not responsive to a conservative treatments for
more than 3 to 6 months, (2) progressive or profound neurological deficit,
(3) static neurological deficit associated with radicular pain, and (4) imaging
studies confirming pathoanatomic features consistent with clinical features.
All patients should have routine cervical spine radiographs, including
dynamic views, computed tomography (CT) scanning, and magnetic resonance imaging (MRI) preoperatively. Intraoperative somatosensory evoked
potentials are useful for monitoring the sensory neurological pathway continuously during the surgery and have been very effective for monitoring the dorsal columns of the spinal cord. This decreases the risk of an obstructed blood
vessel, accidental removal of the breathing tube, or a patient becoming conscious during the procedure. Also, the patient may be monitored with motor
evoked potentials (MEP) and electromyograms (EMG) intraoperatively.
RADIOLOGICAL EVALUATION
Routine cervical spine radiographs, including anteroposterior, lateral,
flexion, extension, and both oblique views, are taken for the evaluation of
degenerative disc disease. The narrowing of the intervertebral disc space
C H A P T E R 3 3 Role of Minimally Invasive Cervical Spine Surgery in the Aging Spine
199
and neural foramen, formation of osteophytes or bony spurs, subluxation
of facet joints, and segmental instability are commonly shown in degenerative cervical diseases. Although cervical radiographs and CT scanning are
useful for visualizing bony anatomy and overall alignment of the spine,
they are limited in the evaluation of neural structures, such as neural foramen, spinal cord or nerve roots, and the presence or absence of neural compression.
Magnetic resonance imaging provides excellent images of spinal structures, such as discs, neural elements, bony structures, muscles, and ligaments. It is the preferred method for confirmatory diagnosis and is generally
recognized in published studies.
SURGICAL TECHNIQUES
Anterior Cervical Microforaminotomy
Transuncal Approach
Under general anesthesia, the patient is placed in a supine position. Under
fluoroscopic guidance, the incision site is marked at the medial border of the
sternocleidomastoid (SCM) muscle perpendicular to the disc space angle. A
2-cm transverse skin incision is made from the medial border of the SCM
muscle. The surgical trajectory from skin incision to pathologic lesion is perpendicular to the sagittal plane of the cervical spine, so the bone must be
opened at the anterolateral spine along the line of the trajectory. In this case,
the uncinate process lies along the perpendicular surgical trajectory. Especially in procedures at C4-C5 or C5-C6 level, a skin incision at the upper or
mid portion of the neck produces such a perpendicular surgical trajectory.
Skin incision to bone exposure is performed as in the previously discussed
approach. The medial 1 to 2 mm of the most medial transverse processes
at the upper and lower vertebrae are removed, and the vertebral artery is
identified. Then, the lateral uncinate process is dissected from the vertebral
artery. The most lateral 2-mm portion of the uncinate is drilled just medial
to the vertebral artery toward the posterior longitudinal ligament. Once the
posterior longitudinal ligament is exposed, compressive lesions, such as herniated soft disc or bone spurs, are excised. Often the posterior longitudinal
ligament is opened to expose the dura mater at the most lateral portion of
the spinal cord and proximal nerve root to detect hidden migrated disc fragments. The thin bone wall of the medial uncinate must not be damaged to
maintain the integrity of the intervertebral disc.
Upper Vertebral Transcorporeal Approach
This approach uses bone opening at the most inferolateral portion of the
upper vertebral body, because the anteroposterior surgical trajectory is
inclined caudally. It is usually used for C6-C7 and C7-T1 cervical surgery,
but it is also used for other levels by placing the skin incision more cephalad.
The vertebral artery is slightly exposed, and a 2-mm medial portion of the
transverse process of the upper vertebra is removed. The bone is opened
at the inferolateral 2- to 3-mm portion of the upper vertebra by drilling
toward the posterior longitudinal ligament. The intervertebral endplate, at
the anterior two thirds of the intervertebral disc, must not be damaged.
The surgical trajectory is directed toward the pathological lesion only
through the most posterior portion. The rest of the procedure is the same
as described previously.
Lower Vertebral Transcorporeal Approach
This technique refers to the location of the bone opening at the lateral portion of the lower vertebra of the intervertebral disc. When an operation is at
a high level such as C3-C4, this surgical technique is required to expose the
pathologic lesion, because the surgical trajectory from the skin incision to
the target site is inclined cephalad.
The transverse skin incision about 1 to 2 inches then the platysma can
be split longitudinally or dissected transversely. Blunt dissection proceeds
medially to the sternocleidomastoid muscle and internal carotid artery
toward the anterior aspect of the cervical vertebrae.
Case Studies
A 67-year-old woman had continuous radiating pain into her left arm. During 6 months of conservative treatment and physiotherapy, the symptoms
were not relieved. Plain radiographs showed decrease in the height of disc
space at the level of C5-C6 (Figure 33-1 ). Cervical MRI demonstrated narrowing and obstruction of neural foramen at the levels of C5-C6 and C6-C7
(Figure 33-2 ). e decision was made to perform a microsurgical decompression with anterior foraminotomy at both cervical segments. Transuncal
C5-C6
approach at C5-C6 and upper vertebral transcorporeal approach at C6-C7
were performed, respectively. Plain and dynamic radiographs and threedimensional (3-D) cervical CT were done postoperatively (Figure 33-3).
e radiculopathy was significantly improved after the operation. e
patient was symptom free, and 3-D CT and dynamic radiographs showed
no instability of operated levels at follow-up.
C5-C6
C5-C6
A
F IG UR E 3 3 - 1 The plain and dynamic radiographs show decreased disc space at C5-C6 level, preoperatively. A: AP view, B: lateral view, C: flexion view,
D: extension view.
B
C
D
200
P A R T I V Surgical Treatment Modalities: Cervical Spine
B
C5-C6
C6-C7
A
F IG UR E 3 3- 2 A: Cervical MRI sagittal view shows narrowing the neural foramen at C5-C6 and C6-C7 levels. B: Cervical MRI axial view shows narrowing
the neural foramen by the compressive pathologic lesion at C5-C6 level. C: C6-C7 level.
C5-C6
C
C5-C6
C6-C7
C6-C7
A
F IG UR E 3 3 -3 Postoperative cervical CT. A: The 3-D image shows two bony openings that were drilled via transuncal approach and upper
vertebral transcorporeal approach respectively. B and C: Axial CT images also demonstrate the bone openings and decompression of the pathologic lesion
at C5-C6 and C6-C7 levels.
B
The longus colli muscle is split longitudinally to expose the lateral portion
of the cervical spine. An anterior cervical retractor system (e.g., Thompson
retractor) is applied before the operating microscope. Endoscopic surgery
C5-C6
spurs are removed with microdissectors and various curettes. The nerve root
and most lateral portion of the spinal cord are released. Surgical closure is
made as in other anterior cervical surgery.
C
C6-C7
has been performed for this operation. The medial portion of the transverse
process at the rostral and caudal vertebrae are identified. The most medial,
upper 1- to 2-mm portion of the transverse process at the lower vertebra is
removed, and the vertebral artery is identified. Using a 1- or 2-mm cutting
drill bit, the superolateral 2- to 3-mm portion of the lower vertebra is drilled
posteriorly just medial to the vertebral artery.
A cephalically inclined surgical trajectory leads the drilling toward the
target pathologic lesion posteriorly. Compressive herniated soft disc or bone
Percutaneous Cervical Nucleoplasty
Percutaneous disc decompression, regardless of technique, has been based
on the concept that a small reduction of volume in a closed hydraulic space
results in a disproportionately large drop of pressure in the intervertebral
disc space. Percutaneous cervical discectomy (PCD) has been developed
as an effective treatment method for soft cervical disc herniation. Percuta-
C H A P T E R 3 3 Role of Minimally Invasive Cervical Spine Surgery in the Aging Spine
201
A
F IG UR E 3 3- 4 Intraoperative PCN procedures in different levels. A: C3-C4, B: C4-C5, C: C5-C6, D: C6-C7.
neous cervical nucleoplasty (PCN) is one of the new minimally invasive
techniques that uses radiofrequency energy to ablate the nucleus pulposus
(Figure 33-4).
Inclusion criteria are the same as those of other conventional anterior
cervical foraminodiscectomy. Exclusion criteria are extruded disc fragment,
hemorrhagic diathesis, spondylolisthesis, spinal canal stenosis, ossification
of posterior longitudinal ligament (OPLL), previous surgery at the indicated level, and cases of myelopathy.
Under local anesthesia, the patient is placed in a supine position as for
other anterior cervical approaches. The anterior cervical spine is palpated
with the fingertips, and a spinal needle is used to puncture the right side of
the neck and is then passed into the indicated disc space under fluoroscopic
control. The fiber of the Perc-D SpineWand (ArthroCare Corporation, Austin, Tex.) is inserted through the 18-gauge needle. The wand is connected
to the standard ArthroCare power generator. The power for nucleoplasty
ablation is set at 3 W with a setting of 1 second for coagulation. If there is
no syndrome of pain, the SpineWand is placed in the right space on the disc
and then the Coblation device is activated for 14 seconds with fluoroscopic
monitoring. When the SpineWand is returned to the annulus, coagulation is applied for 1 second to shrink the surrounding collagen and widen
the channel. This process is repeated four to six times during the surgical
procedure.
B
Percutaneous Endoscopic Discectomy
Under local or general anesthesia, the patient is positioned and other surgical preparations are performed as for other cervical surgery. The exact target
level is confirmed fluoroscopically.
A 2- to 3-mm skin incision is made, a spine needle is placed in the target
disc using fluoroscopic guidance, and a narrow guide wire is passed through
the needle. The needle is removed. A blunt trocar is introduced over the
guide wire down to the interspace, followed by the cannula, and the central
elements are removed. A trephine is inserted through the cannula and the
annulus is cut in a circular fashion. Minicurettes are used to loosen and
remove disc material before a suction-irrigation system is introduced and the
discectomy is performed with a guillotine cutting blade. The instruments
included a probe, grasper forceps, and laser fiber. Movement in a fan sweep
maneuver is critical; a 25-degree rocking excursion of the cannula hub from
side to side increases the removal up to a 50-degree cone-shaped area within
the disc space. The procedure is closely monitored with the fluoroscope and
endoscope. The holmium:yttrium-aluminum-garnet laser with right angle
or side-fire probe facilitates this discectomy. In addition, nonablative levels of holmium laser energy or thermodiscoplasty causes shrinking of the
collagen and fibrocartilage; this tightening effect further decompresses and
hardens the herniated cervical disc.
C
D
Microendoscopic Discectomy
Microendoscopic discectomy (MED) (Figure 33-5) is used when there
is a need to visualize across the spinal canal and an operating microscope is insufficient. Positioning and anesthesia are the same as those
for a posterior cervical microendoscopic foraminotomy. Single level
and multilevel decompression can be performed with the standard
fixed-aperture tubular retractor. For two-level decompression, the tube
can be angled rostrally or caudally. The incision should be centered on a
point between the two interspaces. For a three-level grated decompression,
a longer incision can be used. A longer incision allows better visualization
and decreases the amount of soft tissue resection required. For multilevel
decompression, an expandable working channel can be used. Generally, it
is easiest to begin with the most caudal level first, minimizing the amount
of blood running into the field. After the level has been confirmed with
fluoroscopy, soft tissues are cleared off the level of interest and the lateral
edges of the lamina are defined. To minimize the risk of injury to the spinal
cord, a high-speed drill is used to remove the lateral aspect of the lamina.
If an ipsilateral foraminotomy is not needed, take care not to injure the
facet capsule. Otherwise, the high-speed burr and Kerrison punches can be
used to perform foraminotomy. The tube is then angled medially, exposing
the base of the spinous process. The high-speed burr is used to drill away
the base of the spinous process. It is usually necessary to angle the working
channel rostrally to resect the remainder of the spinous process. Fluoroscopy can be used to confirm the rostrocaudal extent of the decompression.
The ligamentum flavum is initially left intact to protect the underlying dura
mater. But, to get adequate visualization of the contralateral aspect of the
spinal canal, the ligamentum flavum is resected with the aid of curettes and
Kerrison punches. The undersurface of the contralateral lamina should be
drilled away to provide better visualization. Decompression is complete
when a nerve hook can be passed along the lateral aspect of the dura mater
contralaterally. Once a single level has been decompressed, further levels can
be decompressed with a high-speed burr or a Kerrison punch. Bone bleeding should be waxed as soon as possible to reduce the risk of venous air
embolism. The operative wound is then repaired in layers like other cervical
spine procedures.
DISCUSSION
In recent years the general trend in spinal surgery has been one of reductionism and minimization. The concept of minimally invasive cervical spine surgery is ideal for the management of cervical aging disease.
The extensive muscle dissection required for the traditional posterior
approaches leads to significant postoperative pain and the potential
for postoperative deformity. By minimizing the extent of muscular dissection and by preserving the contralateral soft tissue, the less invasive
202
P A R T I V Surgical Treatment Modalities: Cervical Spine
C4
C5
A
F IG UR E 3 3- 5 A: A guide pin (arrow) is inserted into the inferior aspect of the facet of C4 to access the neural foramen at C4-C5. B: And the Serial
dilator (arrow) is docked.
approaches may lead to shortened hospital stays, decreased narcotic use,
and better outcomes.
vical disc herniation in 1928. Subsequently, the landmark paper by Mixter
and Barr
sciatica, and provided evidence that laminectomy and disc excision could
successfully relieve pain associated with radiculopathy. Bailey and Badgley
Cloward
with interbody fusion in the 1950s. Hirsch
cervical discectomy without fusion. Fukushima10 introduced the ventriculofiberscope in 1973 and further enhanced the foundation for percutaneous
endoscopic cervical discectomy.
lowering intradiscal pressure through devices inserted percutaneously into
the intervertebral disc space have been shown to be safe and effective. A
number of techniques have recently been developed that are applicable in
the treatment of degenerative disorder on the cervical spine.
3
Stookey
described the clinical symptoms and anatomic location of cer-
4
clearly established the relationship between herniated discs and
6
, and Robinson and Smith7 popularized the anterior approach
3,4
8
and Robertson9 recommended
Minimally invasive treatments aimed at removing nuclear materials and
5
,
C4
C5
B
avoids osteoarthrodesis or arthroplasty with disc prosthesis. This technique
is efficient with good results and low morbidity, especially in an aging spine.
Percutaneous Cervical Nucleoplasty(PCN)
Percutaneous disc decompression, regardless of technique, has been based
on the principle that a small reduction of volume in a closed hydraulic space,
like an intact disc, results in a disproportionately large reduction of pressure. Percutaneous cervical decompression has been developed as an effective treatment option for soft disc herniation. PCN is a minimally invasive
technique that uses radiofrequency energy to ablate the nucleus pulposus in
a controlled manner for disc decompression.
Treatment of cervical disc hernia with PCN is safe to perform, and the
efficacy of this technique is good in patients. The advantage of PCN is that
it reduces the volume and pressure of the affected disc without damaging
other spinal functional units. Ablation of a relatively small volume of the
nucleus pulposus results in a significant reduction in intradisc pressure. Histologic examination revealed no evidence of direct mechanical or thermal
Microsurgical Anterior Cervical Foraminodiscectomy
In the 1930s, Spurling and Scoville11, and Frykholm12 pioneered the posterior cervical approach for the treatment of cervical radiculopathy. But
the posterior approach was limited in dealing with central compressive
pathology and the open approach was associated with significant muscle
morbidity. Subsequently, in the 1950s, the anterior approach was described
and popularized. Compared to the open posterior approach, the anterior
approach is generally associated with shorter recovery times but has a
greater potential for complication. Anterior cervical discectomy and fusion
(ACDF) results in a loss of mobility at the operated level, and increases rates
of degenerative disc disease in adjacent levels. In addition, the compressive
pathological factors are located anteriorly, and the immediate surgical outcomes of anterior discectomy are fairly good. However, the consequences
of anterior disc-ectomy are obvious. Conventional anterior discectomy and
fusion requires complete removal of the remaining disc in the intervertebral
disc space, which results in loss of the functional motion unit.
Microsurgical anterior cervical foraminodiscectomy (MACF) is a minimally invasive technique and one that permits anatomic and functional
preservation of the functional motion unit of the cervical spine. Therefore
this technique was named functional cervical disc surgery. This method
13
damage to the surrounding tissues in human cadavers. Given these radical
thermal penetrations, high temperatures and lethal thermal doses do not
occur in small regions outside of the nucleus or within the bone endplates
in human cadavers.
14
A small number of complications are associated with PCN. With the
approach from the anterior neck to disc space, it is important to monitor
the distance from the tip of the needle to the spinal canal. Therefore monitoring of the needle is essential during this procedure. X-ray fluoroscopy
is used to confirm the correct position of the needle tip during placement
of the needle, permitting accurate nucleoplasty of the intervertebral disc.
Vascular injury can occur if the device contacts an artery or a vein. Particular care should be taken to avoid puncture of the anterior annulus. But,
according to Chen’s study
15
in human cadavers, intradiscal pressure was
markedly reduced in the younger, healthy disc cadaver. In the older, degenerative disc cadavers, the change in intradiscal pressure after nucleoplasty
was very small. There was an inverse correlation between the degree of disc
degeneration and the change in intradiscal pressure. Their conclusion is
that pressure reduction through nucleoplasty is highly dependent on the
degree of spine degeneration. Nucleoplasty markedly reduced intradiscal
pressure in nondegenerative discs, but had a negligible effect on highly
degenerative discs.
C H A P T E R 3 3 Role of Minimally Invasive Cervical Spine Surgery in the Aging Spine
203
Percutaneous Endoscopic Cervical Discectomy
Since the first description of cervical percutaneous discectomy by Tajima
and colleagues
(PED) may be considered a good alternative to the standard anterior cervical discectomy and fusion for treating soft cervical disc herniation. The goal
of this procedure is to decompress the spinal nerve root through percutaneously removing the herniated mass and shrinking the nucleus pulposus
while the patient is under local anesthesia.
Most patients who have cervicobrachial neuralgia caused by disc herniation experience good response to medical treatment. However, symptoms
related to perineural cicatricial fibrosis caused by prolonged pressure on the
nerve root could become irreversible. Therefore the occurrence or aggravation of a neurologic deficit, even after an adequate period of conservative
treatment, requires consideration of surgical decompression. PED is indicated in the surgical treatment of soft cervical disc herniation not contained
by the posterior longitudinal ligament, which includes central, lateral, and
foraminal disc herniation.
Minimally invasive PED under local anesthesia can prevent such
complications as epidural bleeding, perineural fibrosis, graft-related problems, dysphasia, hoarseness, and so on. It also maintains the stability of
the intervertebral mobile segment and provides patients with excellent
cosmetic effect and early recovery. Moreover, it does not preclude further
open procedures even after treatment failure. But PED is contraindicated
in patients presenting with a severe neurologic deficit, segmental instability,
acute py-ramidal syndrome, progressive myelopathy, and other pathologic
conditions, such as tumor, fracture, infection, and nerve entrapment with
scar tissue from previous surgery. This procedure is also contraindicated
in patients who have migrated discs, calcified disc protrusion, ossification
of the posterior longitudinal ligament, marked spondylosis with disc space
narrowing, and neurologic or vascular pathologies mimicking disc hernia-
17
tions.
16
in 1981, percutaneous endoscopic cervical discectomy
Microendoscopic Discectomy
Many studies have described the effectiveness of the anterior approach for
the treatment of cervical disc prolapse and spondylotic stenosis. Although
the anterior approach is more commonly performed for the treatment of
cervical disc disease, the posterior approach has distinct advantage in
selected cases of foraminal stenosis and posterior-lateral disc herniation.
Frykholm and Scoville described posterior foraminotomy through partial resection of the medial part of the facet joint to relieve the compression
of the cervical nerve root in radiculopathy patients. Conventional posterior
approaches have the disadvantage of detaching the extensor cervical muscles
from the laminae and the spinous process. This operative trauma to the cervical paraspinal muscles is a major cause of postoperative complications in
the form of persistent neck and shoulder pain, and sometimes spinal instability may result.
Roh et al19 described the use of microendoscopic posterior cervical
foraminotomy in a cadaveric study, and Burke and Caputy
the use of the same technique. The microendoscopic technique has the
advantage of providing a minimally invasive approach through transmuscular dilatation. However, the disadvantage of this procedure is that it only
allows two-dimensional visualization, and the view often gets blocked by
bleeding or obscured by fragments during removal. The main limitation of
this procedure is in the treatment of severe bony stenosis that necessitates
laminectomy to decompress the spinal cord.
18
20
reported on
CONCLUSIONS
These surgical options for the treatment of cervical spinal degenerative disorders in the aging spine provide good relief of the patient’s symptoms, such
as radiculopathy. It is evident that PCN, MACF, PED, and MED are varied
methods of minimally invasive surgery resulting in short-term recovery and
return to full functions.
In addition, in MACF there is the special potential for the problems in
the long term. First, the disc resection is limited to its lateral part, and the
facet joint is not damaged. As a result, the risk of postoperative instability
is very low in MACF. No osteoarthrodesis or arthroplasty by disc prosthesis is necessary. Second, the nerve root decompression is perfectly achieved
regardless of whether the pathology is soft disc or canal stenosis, and it can
be addressed under direct visual control. As with other anterior techniques,
however, this procedure is applicable only if the compressive lesion is located
anterior to the spinal cord.
Although these microsurgical procedures are technically demanding in
executing adequate decompression of the spinal cord, substantial anatomic
knowledge is required, and the technique should be mastered thoroughly
with cadaveric dissection. This technique can be a favorable anterior surgical
procedure in older people with various degenerative pathologies that cannot
be treated with other minimally invasive techniques in the aging spine.
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