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Hindawi Publishing Corporation
Advances in Orthopedics
Volume 2012, Article ID 307916, 15 pages
doi:10.1155/2012/307916
Rev iew Ar ticle
Laminoplasty Techniques for the Treatment of
Multilevel Cervical Stenosis
LanceK.Mitsunaga,EricO.Klineberg,andMunishC.Gupta
Department of Orthopaedic Surgery, University of California Davis Medical Center, 4860 Y Street, Suite 1700,
Sacramento, CA 95817, USA
Correspondence should be addressed to Lance K. Mitsunaga, lance.mitsunaga@ucdmc.ucdavis.edu
Received 15 July 2011; Accepted 14 November 2011
Academic Editor: Joseph S. Butler
Copyright © 2012 Lance K. Mitsunaga et al. This is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly
cited.
Laminoplasty is one surgical option for cervical spondylotic myelopathy. It was developed to avoid the significant risk of compli-
cations associated with alternative surgical options such as anterior decompression and fusion and laminectomy with or without
posterior fusion. Var ious laminoplasty techniques have been described. All of these variations are designed to reposition the
laminae and expand the spinal canal while retaining the dorsal elements to protect the dura from scar formation and to preserve
postoperative cervical stability and alignment. With the right s urgical indications, reliable results can be expected with laminoplasty
in treating patients with multilevel cervical myelopathy.
1. Introduction
While multilevel cervical stenosis may occur for a variet y of
reasons, it is usually due to cervical spondylosis or ossifica-
tion of the p osterior longitudinal ligament (OPLL). Options
for decompression of the canal include either anterior or
posterior approaches. For multilevel disease, most surgeons
prefer posterior decompression. Posterior decompression
has the advantage of addressing multiple levels with one
incision. However, this approach is hindered by the late
complication of kyphosis with decompression alone or the
loss of motion and adjacent segment degeneration if pos-
terior decompression is performed in conjunction with
fusion [1, 2]. Laminoplasty is a technique that indirectly de-
compresses the spinal cord and preserves neck motion by
avoiding fusion. This is accomplished by hinging the laminae
open on one or both sides to allow the spinal cord to migrate
posteriorly away from anterior compressive structures.
Laminoplasty was initially described by the Japanese in the
early 1970s to treat ossification of posterior longitudinal
ligament [3]. By leaving the dorsal structures in situ, lamino-
plasty was d eveloped to avoid the problems associated
with laminectomy, such as kyphosis, instability, and delayed
neurologic problems due to scar invasion. Laminoplasty has
become increasingly popular in North America as experience
with laminoplasty techniques has grown and its application
has expanded to treat other causes of multilevel cervical
stenosis besides OPLL, such as cervical spondylotic myelopa-
thy (CSM). The goals of this chapter are to discuss the ad-
vantages and disadvantages of laminoplasty, key technical
points regarding different laminoplasty techniques, along
with the complications and outcomes of laminoplasty.
2. Advantages of Laminoplasty
Laminoplasty allows the spinal cord and the neuroforamen
to be decompressed w ithout directly removing anterior pa-
tholog y. By preserving the dorsal elements of the spine,
laminoplasty preserves spine stability and alignment and
decreases the risk of postlaminectomy kyphosis and insta-
bility [1, 4–23]. Additionally, since fusion is not required,
complications such as fixation failure, pseudarthrosis, loss
of motion, and adjacent segment degeneration do not occur.
This may allow earlier mobilization and rehabilitation com-
pared to other surgical options. In addition, laminoplasty
can avoid graft-related complications such as graft extrusion,
settling, collapse, dislodgement, and fracture. The financial
2 Advances in Orthopedics
costs associated with laminoplasty are potentially minimized,
as well, without the need for lateral mass screws and rods
used during fusion. With laminectomy, epidural scar forma-
tion can form between the dura and muscle leading to
postoperative pain and neurologic compression [24–26].
However, with laminoplasty, the lamina is preserved and it
protects the dura from this “postlaminectomy membrane.”
Preserving the lamina also makes revision procedures re-
quiring posterior approaches safer. Finally, laminoplasty has
the advantage of avoiding the potential morbidity that can
accompany anterior approaches, such as dysphagia, recur-
rent laryngeal nerve injury, dysphonia, and injury to the
esophagus or carotid sheath contents.
3. Disadvantages of Laminoplasty
Laminoplasty does not address neck pain, if that is a compo-
nent of a patient’s symptomatology. Laminoplasty may even
cause worse neck pain than anterior procedures, especially in
the early postoperative period, due to the extensive muscle
stripping that accompanies this procedure. This has been
shown to be especially true if the dissection and laminoplasty
is carried down to C7 [27, 28]. Although laminoplast y does
not require fusion, range of motion is still reduced following
laminoplasty [4, 8, 18, 20, 29–37]. Once the laminoplasty
hinge has been opened, it requires some stabilization to
maintain the expanded position during healing. This fixation
is associated with some cost, bone graft may be required, and
there is the potential for nonunion or failure. In addition,
the longitudinal incision associated with laminoplasty may
be less cosmetic than anterior incisions.
4. Indications
Cervical laminoplasty is indicated for cases of cervical my-
elopathy or myeloradiculopathy due to central stenosis
extending more than three intervertebral disc spaces. This
can be due to multilevel degenerative cervical spondylosis,
OPLL, multilevel disc herniations, certain spinal cord tu-
mors, neuromuscular disorders, acute traumatic central cord
syndrome, or developmental cervical stenosis.
5. Contraindications
Kyphotic deformity is a contraindication for laminoplasty.
In the kyphotic spine, laminoplast y does not address the
cord compression anteriorly and leads to decreased canal
expansion and dorsal migration of the cord [38]. In addition,
laminoplasty can contribute to spine instability and worsen
the kyphosis in these cases. Ideal laminoplasty patients
have lordotic cervical spine alignment and no instability on
dynamic radiographs. Laminoplasty can be done in neutral
spines (generally defined as less than 4 degrees of either
kyphotic or lordotic angulation) but lordotic alignment is
preferable since multiple studies have documented loss of
lordosis after laminoplasty [12, 20, 29, 30, 39–51]. In patients
with radiographic evidence of instability, laminoplasty alone
may worsen the instability and should be accompanied by
fusion. The ideal laminoplasty patient also has minimal
complaints of neck pain. Laminoplast y may not address neck
pain and, in fact, may even worsen neck pain. However,
the presence of mild neck pain is not a contraindication
to laminoplasty, provided the patient accepts the risk of
postoperative neck pain. Stenosis at one or two levels is
not an indication for laminoplasty since the short length of
decompression achieved in these cases does not yield the
same amount of spinal cord migration away from anterior
structures. Post-laminoplasty instability may also be an issue
in patients with rheumatoid arthritis, which is a relative
contraindication for laminoplasty [52].
6. Preoperative Considerations
As always, a thorough history and physical exam, especially
a thorough neurologic exam, are imperative prior to per-
forming a laminoplasty. Radicular symptoms may suggest
the need for a foraminotomy, while significant neck pain may
indicate the patient for posterior fusion in combination with
laminoplasty. AP/lateral views of the cervical spine and CT
myelogram or MRI of the cervical spine is also critical. These
imaging modalities can be used to correlate with clinical
findings and to assist with surgical planning. They are also
important if cervical foraminotomy is needed as they can
be used to help assess the level(s) and location of nerve
root compression. Upright plain films are used to determine
preoperative kyphosis and one’s ability to perform posterior
surgery. Flexion-extension films should be evaluated for any
evidence of instability that may need to be addressed with a
posterior fusion.
7. Patient Positioning
We prefer to use the 180-degree operating room setup and
a Mayfield tong attachment with gelfoam bolster pads on a
standard table. The Mayfield tongs allow control and stability
of the cervical spine during positioning. O ther alternative
operating room table and positioning options include a
Jackson frame with a Mayfield tong attachment or a Stryker
or Jackson frame with Gardner tong traction.
Intubation must be achieved cautiously. In cases involv-
ing severe myelopathy, awake fiberoptic intubation is often
recommended to minimize the risk of spinal cord injury with
neck extension and to allow monitoring of neurologic status
after intubation. Neuromonitoring electrodes are placed
and baseline somatosensory and transcranial motor evoked
potentials are recorded pr ior to commencement of the case.
Mayfield tong retractors are placed and the patient is placed
prone.
The table should be placed in reverse Trendelenburg po-
sition at about 20–30 degrees to help with venous drainage
and visualization. The shoulders are taped down to provide
more complete radiographic visualization of the lower cer-
vical spine. The head should be in maximum capital flexion
and the cervical spine in a neutral position to maximize inter-
laminar and interspinous space and to open the facet joints
during foraminotomy. The exception to this is if posterior
Advances in Orthopedics 3
fusion is planned, in which case slight extension of the neck
during positioning or prior to fusion is necessary. The pre-
ferred patient positioning setup is shown in Figure 1.After
patient positioning, SSEP and MEP signals are again checked
to see if there is any c hange from baseline that might require
repositioning. The posterior cervical spine is then prepped
and draped in the usual sterile fashion, including the occip-
ital protuberance rostrally to the T3 spinous process caudally.
8. Laminoplasty Techniques
Oyama et al. first described cervical laminoplasty in Japanese
in 1973 as a treatment for OPLL [3]. In this initial expansive
laminoplasty procedure, the “Z-plasty” of the cervical spine,
the spinous processes are removed, the lamina is thinned
to the lamina-facet junction, and a Z-shaped cut is made
between the laminae which are opened and fixed with suture
or wire (Figure 2). Since its initial description by Oyama,
laminoplasty techniques have been constantly refined. Most
of these changes relate to how the cuts in the lamina or
spinous process are made and how the laminae are secured in
an open position—with wires or heavy sutures, bone anchors
or bone blocks, hydroxyapatite blocks, miniplates, local
spinous process autograft, and combinations thereof. All
variations in laminoplasty techniques maintain the common
theme, however, of repositioning the laminae, expanding
the canal, and preserving the dorsal elements to maintain
stability. In general, none of these technical variations have
proven to be any safer or efficacious than the other. There
are generally three categories of laminoplasty techniques: the
“open door” laminoplasty, the “double door” laminoplasty,
and the various muscle-sparing laminoplasty techniques.
We will describe these techniques in detail in the following
sections.
9. Expansive Open-Door Laminoplasty
(Also Known as the Hirabayashi,
Open-Hinged, or Single-Door Technique)
Hirabayashi et al. simplified the Z-plasty described by Oyama
in the e arly 1980s with his unilateral expansive open-door
laminoplasty [4, 34]. In this technique, a hinge is created on
one side of the lamina-spinous process-ligamentum flavum
complex. This allows the roof of the canal to be opened on
the contralateral side leading to an expansion of the spinal
canal.
Most commonly, laminoplasty is performed from C3 to
C7 and all these levels need to be exposed. This starts with
a midline longitudinal posterior incision from the occipital
protuberance down to the T1 spinous process. With electro-
cautery, dissection proceeds through the midline fascia and
ligamentum nuchae and the spinous processes from C2 to T1
are exposed. Levels can be identified by palpation and visual-
ization of the prominent, bifid C2 spinous process. Preserve
the supraspinous and interspinous ligaments at the proximal
and distal extents of the exposure during this approach but
Bovie electrocautery can be used to incise these ligaments in
the midline at the planned laminoplasty and foraminotomy
Figure 1: Photo demonstrating proper patient positioning. Patient
is prone and the head is secured by Mayfield tongs without traction.
The table is placed in the reverse Trendelenburg position. Shoulders
are taped down and the neck is in slight flexion.
Figure 2: In the o rig inal “Z-plasty,” after troughs are drilled at
the junction between the lamina and lateral mass, the laminae are
thinned, a “Z” is cut in the laminae with a drill, and, as shown
here, the laminae are spread apart and held with wire or suture to
maintain the expanded canal position.
levels. Also preserve the muscular attachments to C2 as
much as possible to minimize risk of postoperative kyphotic
deformity between C2 and C3. This is facilitated by first
exposing the C7 lamina, retracting the paravertebral muscles
at this level, and continuing this dissection rostrally to
the upper part of the C3 lamina. Complete this midline,
subperiosteal dissection of the paravertebral muscles for the
C3 to C7 spinous processes and retract these muscles laterally
off the spinous processes, laminae, and medial aspect of the
facets. Staying in the natural, avascular, subperiosteal plane
prevents damage to the paraspinal muscles and minimizes
blood loss. Figure 3 shows the exposure required to perform
a laminoplasty. This dissection needs to be extended as far
as the lateral masses but the facet capsules must be preserved
unless fusion is being performed. Hemostasis at all times can
be achieved with monopolar or bipolar electrocautery.
Again, the C2 extensor muscular attachments do not
need to be released. If, however, a decompression is necessary
at the C2 level and undercutting of the lamina with a burr
is not adequate, a laminoplasty can be done at C2 as well.
In this case, the C2 extensor muscles can be released or
taken off with a thin osseous sleeve and subsequently sutured
back down to the C2 dorsal structures. If a foraminotomy is
planned at C2-C3, the extensors on the inferior half of C2
4 Advances in Orthopedics
Figure 3: Intraoperative photo showing laminoplasty exposure.
Following midline dissection along the avascular subperiosteal
plane, paraspinal muscles are retracted laterally and the spinous
processes, lamina, and medial aspect of the facets should be com-
pleted denuded of soft tissue.
are released so the facets can be visualized adequately. At this
point, once the soft tissues have been reflected off the spinous
processes and laminae, retractors can be placed on the sides
of the wound and, if necessary, rostrally and caudally, to facil-
itate visualization. The microscope may also be extremely
helpful for visualization, especially during foraminotomy,
decompression, and creation of the laminar osteotomies.
In the expansive open-door laminoplasty, the opening
side of the lamina should be cut before the hinged side to
minimize blood loss. The opening side is usually placed on
the side with worse radicular symptoms or more stenosis
because, on this side, it is technically easier to perform
a foraminotomy to decompress the neuroforamen. If it is
necessary to perform a foraminotomy on the hinged side,
this should be done first to prevent detachment of the
lamina and because this is technically more demanding.
Using controlled, side-to-side brushing motions with a 2 or
3 mm cutting burr or high-speed microdrill, a trough is made
at the junction of the lamina and lateral mass from C3 to
C7 by decorticating the posterior aspect of the lamina (see
Figure 4(a)). Extra caution should be used at the superior
aspect of the lamina, where there is no ligamentum flavum to
protect the dural sac. The t roughs, created rostral to caudal
from one level above to one level below the stenotic levels,
should be perpendicular to the lamina. The facets should
not be violated. Following thinning of the lamina down to
a thin cortical layer, use a curette to free the ligamentum
flavum off the inferior aspect of the C7 lamina. Complete the
laminar cuts just medial to the pedicles with a 2 or 3 mm
Kerrison punch by removing the thin rim of remnant lamina
and associated ligamentum flavum from caudal to rostral.
Epidural venous bleeding can be controlled with thrombin
gel and bipolar electrocautery.
Ne xt, for the “hinged” side of the laminoplasty, another
trough is made at the junction of the lamina and lateral
mass with minimal disruption of the facet capsule to prevent
postoperative instability. While a 2 mm cutting burr or high-
speed drill can be employed for this portion of the procedure,
we find that a 6 mm diamond burr is useful to cut the outer
cortex in the process of creating a greenstick fracture on the
hinged side as it minimizes the risk of completely breaking
through the inner cortex of the lamina. This large burr
tip also helps create a slightly wider trough on this hinged
(a)
(b)
Figure 4: Sawbones model of an open-door laminoplasty. A trough
has been drilled in the lamina at the lamina-lateral mass junction
with a burr until there is a thin remnant of lamina left. This cut
has been completed with a Kerrison punch (a). After the complete
trough on the o pen side, a second trough is drilled on the hinge side.
Expand the canal and the opening on the open side with a curette on
the open side between the laminae and lateral mass while rotating
the lamina towards the hinged side with a Kocher, as shown in (b).
side so the walls of the trough do not contact each other
when the door is opened which would limit the amount of
decompression. Again, the lamina is thinned with a burr by
removing the outer cortex and approximately one half of the
cancellous bone. Do not violate the inner cortex which will
act as a hinge. To prevent excessi ve thinning of the lamina
on the hinged side and complete dissociation of the entire
lamina, it is helpful to periodically assess the amount of
“give” in the spinous process when it is manipulated and
to use the depth of the lamina on the opened side as a
reference for how deep the trough should be on the hinged
side. Additionally, a curette can be placed on the open side
and pulled upwards. When motion in the lamina is seen with
this maneuver, the trough on the hinged side is complete.
The top and bottom laminae of the open side which will be
included in the laminoplasty can be separated from adjacent
levels with a Kerrison Rongeur to cut the lamina and attached
ligamentum flavum. This creates three free borders for the
“door” which can now hinge open.
Once the laminae are thinned sufficiently, the posterior
elements are more flexible and the lamina can be opened very
gradually and carefully by additional thinning of the hinged
bone, pulling the spinous process toward the hinged side,
and lifting the lamina off the spinal cord with a curet on the
opening side. Opening the laminae as a single unit preserves
the intraspinous ligaments and dorsal structures that help
Advances in Orthopedics 5
stabilize the spine. This can be accomplished by opening
the lamina at each level gradually and to the same degree
as the other. In this way, the gap on the open side between
the lamina and facet is increased and a greenstick fracture is
established along the trough on the hinged side. If this step
is performed with too much force or speed, the inner cortex
on the hinged side can fracture. In this case, laminectomy
with fusion or stabilization of the hinged side is required.
Additionally, if control of the lamina is lost and the door
inadvertently snaps closed, this can injure the spinal cord.
A Penfield dissector or curette can be helpful to expand the
opening and the lamina can be rotated towards the hinged
side with a Kocher (see Figure 4(b)). A Woodsen probe
or elevator can be used to release any adhesions between
the dura and ventral lamina on the opened side. Laminar
opening is made easier with posterior elements that are
more pliable, and this can be achieved with division of the
supraspinous and interspinous ligaments at C2-C3 and C7-
T1 and/or release of the ligamentum flavum on the opening
side of the l amina. Once pulsatile flow in the dura is noted,
which is usually at about 8–10 mm of opening, adequate
canal expansion has been achieved. Hemostasis is achieved
with gelfoam or surgicel and epidural bleeders are controlled
with bipolar electrocautery. Bony bleeding is controlled with
bone wax on a kittner or other local hemostatic agents.
In his initial description, Hirabayashi stabilized the lam-
inae in an open position with sutures through the facet cap-
sule and spinous processes on the hinged side. Titanium
miniplates with or without allograft or autograft, allograft
stabilized with CG clips, stainless steel wiring, facet cables
with and without allograft, various suture techniques, ce-
ramic implants, bone anchors placed through the lateral
mass, and various structural wedge allografts and autografts
are other modified techniques that have been described to
keep the door propped in t he open position [6, 46, 47, 53–
58]. The senior authors prefer either a suture anchor or
miniplate for initial stabilization.
Suture anchors are a simple way to maintain the opening
of the laminae. We find them to be a safe and time-efficient
method that minimizes the risk of disrupting the facet joints
and nerve roots. In addition, this technique does not require
grafting or fixation of the lamina to the lateral mass. The
suture anchors are placed into the lateral masses on the
hinged side (Figures 5(a) and 5(b)). We make a hole in the
base of the spinous process using a right-angle dental drill
with a 2 mm burr tip. Once the laminae are hinged open, a
Keith needle is used to bring the nonabsorbable suture from
the suture anchor in the lateral mass through the drill hole
in the spinous process ( Figure 5(c)). Appropriate tension on
the suture is achieved with a slip knot and then square knots
are tied under tension to maintain the laminar opening
(Figure 5(d)).
Our other preferred fixation method involves using tita-
nium miniplates and allograft spacers to hold the laminae
open, as shown in Figure 7. Once the laminae are expanded,
the appropriate allograft size is ascertained by inserting
a trial spacer into the laminar opening (Figure 6). We then
choose a double pre-bent miniplate of appropriate length
which can be fixed to the allograft via a center screw hole.
The miniplate-allograft construct is then placed in the lam-
inar opening such that the cut laminar edges are wedged
securely in the ends of the allograft that are prenotched. The
graft should fit securely in the laminar gap. We then secure
the miniplate with one or two self-tapping 2.0 mm cortex
screws on both the laminar and lateral mass side.
We have found both suture anchors and miniplate fix-
ation to be reasonable methods of maintaining the laminar
opening, as shown in Figure 9.
10. Double-Door Laminoplasty (Also Known
as French Door, Spinous Process-Splitting,
Midline Opening, or T-Saw Laminoplasty)
In Hirabayashi’s expansive open-door laminoplasty, the
spinal cord is decompressed asymmetrically since the door
opens on one side and hinges on the other. In contrast, the
double-door laminoplasty, described by Kurokawa in 1982,
expands the canal symmetrically as the opening is created
in the midline [59]. This is accomplished by splitting
the spinous processes in the midline with the left and
right hemilaminae hinging on the lamina-spinous process-
ligamentum flavum complex bilaterally (Figure 10(a)). In
the double-door technique, the same positioning, draping,
and midline posterior exposure as the open-door technique
is performed. This exposure is carried out laterally to the
middle of the lateral masses. Preserve the semispinalis muscle
attachments to the C2 spinous process as much as possible.
Troug hs are drilled bilaterally with a high-speed drill or
burr at the lamina-lateral mass junction from C3 to C7, just
medial to the pedicle (Figures 10(b) and 10(c)). The inner
cortex, as with the open-door technique, is only thinned. The
spinous processes are then split down the middle. A d rill or
burr is used to thin the lamina and a Kerrison punch is used
to open the lamina in the midline. The midline laminar splits
can be opened with laminar spreaders (Figure 10(d)). The
laminae are lifted off the spinal cord in the midline and held
open like a French door. This allows the spinal cord to drift
posteriorly in t he enlarged canal.
One purported advantage of the double-door technique
is that the decompression occurs directly posterior to the
cord so there is less bleeding from the lateral epidural veins
that often accompanies the open-door technique. Adhesions
between the dura and ventral side of the lamina are freed. The
laminar opening can be fixed with suture passing through the
facet capsules and lamina. In the initial description of the
double-door procedure, the canal was left open. However,
several techniques have been proposed to span the space
between the gapped lamina and to protect t he spinal cord.
These include the use of ceramic/hydroxyapatite spacers,
iliac crest bone graft, rib autograft (Figure 10(e)), or, as
described by K ur okawa, resected spinous process autograft
fixed between the lamina with wires [59–61].
In the Tomita modification of the double-door lamino-
plasty (also known as the “T-saw laminoplasty”), the spinous
processes and laminae are split with a Gigli-like wire-saw
[29, 62](Figure 11). After the ligamentum flavum is re-
sected down the midline above and below the levels to be
6 Advances in Orthopedics
(a) (b)
(c) (d)
Figure 5: Once the door is opened, the laminae can be held in the open position w ith suture anchors. Suture anchors are placed into the
lateral masses of the hinge as shown in (a) and (b). Next, the suture anchor is brought through a drill hole in the spinous process (c). The
suture is tied to prevent closure of the laminoplasty (d).
Figure 6: For titanium miniplate fixation, once the laminae are ex-
panded, use a trial spacer to determine the appropriate allog raft size.
decompressed, a polyethylene sleeve that encompasses a T-
saw is passed superiorly along the epidural space. Grab hold
of the sleeve tip as it comes into view in the C2-C3 interspace.
Advancethesawthroughthesleeveandremovethesleeve
over the saw. After verifying adequate cer vical lordotic
alignment to minimize the risk of cord injury, a reciprocat-
ing sawing motion is used to saw through the midline of
the laminar arch. Irrigate periodically to minimize thermal
damage. Greenstick fractures are then created by using a
high-speed burr to create bilateral troughs at the medial
one-third of the lateral masses. The split laminae are then
opened as with the double-door technique. Carefully free up
any epidural adhesions. Foraminotomies can be done prior
to opening the hinges. The opened canal can be stabilized
with various grafts, including rib or fibula allograft spacers,
autologous spinous process, or iliac crest [29, 63].
The primary disadvantage of the double-door technique
is that it can be technically challenging. This technique also
potentially puts the spinal cord more at risk than the open-
door technique as the dura is just deep to the spinous process
that is split with a burr or saw. Foraminotomy is also techni-
cally demanding and may cause disruption of the hinge.
11. Muscle-Sparing Laminoplasty Techniques
Many problems associated with laminoplasty such as axial
neck pain, postoperative kyphosis,andsegmentalinstability
are thought to be related to neck muscle disruption [12, 33,
64–66]. Various techniques have been described to minimize
Advances in Orthopedics 7
(a) (b)
Figure 7: Sawbones model (a) and intraoperative photo (b) showing miniplate and allograft placed in the laminar opening. The miniplate
has been fixed with 2 screws on both the laminar and lateral mass side.
(a) (b) (c)
Figure 8: Sawbones model showing an increase in A-P diameter of the canal between the preexpanded status (a), after suture anchor
laminoplasty (b), and after laminoplasty with miniplate fixation (c).
(a) (b)
Figure 9: Axial CT scans of patients following expansive open-door laminoplasty. The laminar opening has been maintained with suture
anchors (a) and miniplate fixation (b).
8 Advances in Orthopedics
(a) (b)
(c) (d) (e)
Figure 10: In the double-door laminoplasty technique, a high-speed burr is used to split the spinous processes in the midline (a). The burr is
then used to create troughs bilaterally at the junction of the lamina and lateral mass, as shown in (b) and (c). The hemilaminae are separated
at the midline with a laminar spreader and elevated (d). The expanded canal is then held in the open position with either bone graft or
ceramic/hydroxyapatite spacers (e).
Figure 11: Instead of using a burr for the double-door laminoplasty
technique, with the Tomita modification of the double-door lami-
noplasty, the spinous processes are split in the midline with a Gigli-
like T-saw.
disruption of muscular and ligamentous attachments to t he
lamina and spinous processes.
Shiraishi described a technique designed to minimize
damage to the deep extensor muscles of the cervical spine,
and, in particular, the attachments of the semispinalis cer-
vicis (SSC) and multifidus muscles to the spinous processes
[65](Figure 12). An operating microscope is recommended
for this minimally invasive exposure. A longitudinal midline
incision is made overlying the spinous processes of the
planned laminoplasty levels. For instance, for a C4 and C5
laminoplasty, the incision would overlie the C4 and C5
spinous processes. The nuchal ligament is incised in line with
this incision. Identify the interval between the tips of the C4-
C5 spinous processes, which separates the insertions of the
interspinalis muscles, SSC, and multifidus muscles to the C4
spinous process from the left and right side. This interval is
opened with a nerve retractor such that the muscles attached
to the C4 spinous process on the left are retracted to the
left and vice versa for those muscles attaching on the right
side of the C4 spinous process. The ligamentum flavum and
superior half of the C5 lamina should be visible. Sever the
interspinalis muscles where they attach to the C5 spinous
process. The attachments of the SSC and multifidus muscles
on the C5 spinous process are pulled distally so that the
attachments of the rotator muscles inserting on the inferior
half of the C5 lamina can be seen and dissected off the C5
lamina. By retracting the muscles attached to the C5 spinous
process even more distally and those to the C4 spinous
process laterally, the C5 lamina, the superior border of the C6
lamina, and the C5-C6 intervertebral joint are exposed with-
out taking down any of the SSC or multifidus attachments to
the C4, C5, or C6 spinous processes. Following this exposure
that preserves the attachments of the SSC and multifidus
to the spinous processes, a double-door laminoplasty can
be performed similar to its application with the standard
midline posterior approach.
Others, however, have suggested that it is not disruption
of the extensor muscles that causes axial pain, but disruption
of the musculoligamentous structures attached to the C7
spinous process, such as the trapezius, rhomboid minor, and
Advances in Orthopedics 9
(a) (b) (c)
Figure 12: Illustration (a) and sawbones model (b) showing how a muscle-sparing exposure can be applied to a double-door laminoplasty.
The deep extensor muscles attaching to the C4 spinous process are pulled laterally and those attaching to the C5 spinous process are pulled
distally. The double-door laminoplasty can then be done as with the standard posterior midline exposure with sagittal splitting of the spinous
processes and the creation of bilateral laminar troughs which serve as hinges on which the double-door can open, as shown in (c).
the nuchal ligament [27, 28, 67]. This has led to the recom-
mendation that C 7 should be excluded, if possible, from the
laminoplasty procedure. This may minimize postoperative
neck pain by preserving the C7 spinous process as a fulcrum
for neck muscles and it maintains the stabilizing role the C7
lamina plays in the cervical spine [27, 28, 67]. Alternatively,
if the epidural space at the ventral aspect of the C7 lamina is
tight upon probing, a laminotomy at the superior half of C7
can be done [67].
Others, still, have focused not on disruption of the C7
musculoligamentous attachments as a major source of axial
neck pain, loss of extensor power, and loss of cervical align-
ment, but, instead, disruption of the extensor musculature
and, in particular, the semispinalis cervicis muscle attach-
ments on C2 [21, 32, 33, 68–75]. A t raditional C3-C7
laminoplasty usually requires disrupting and reattaching
the extensor muscle insertions onto C2. Takeuchi, however,
proposed a C3 laminectomy with a C4-C7 laminoplasty to
preserve these muscles and minimize axial neck pain [69].
In another muscle-sparing modification, some recommend
a C3 laminectomy, a laminoplasty from C4 to C6, and an
undercutting of the inferior two-thirds of the lamina of C2
and superior half of the lamina of C7. The goal of this
technique is to achieve an adequate decompression at C3-
C7 but to minimize the incision, the pot ential for instability,
and the amount of bon y work and muscle disruption. In
another muscle-sparing modification aimed at preventing
post-laminoplasty cervical malalignment, Shiraishi and Yato
proposed a variation of the double-door laminoplasty pro-
cedure that expands the C2 spinal canal while preserving all
the muscular attachments to each half of the split C2 spinous
process [70].
12. Foraminotomy
Performing a foraminotomy in association with lamino-
plasty is indicated in cases of significant radiculopathy or
if there is radiographic evidence of neuroforaminal stenosis
regardless of symptoms. This is done both to prevent the
development of nerve root compression postoperatively and,
possibly, to minimize postop neck pain due to nerve root
stretch and compression. Some also recommend performing
a for aminotomy based on abnormal neuromonitoring sig-
nals, especially those involving the C5 nerve root, which is
particularly vulnerable to traction injury. Others, still, rou-
tinely perform bilateral C4-C5 foraminotomies to minimize
the risk of a C5 root palsy.
The use of an operating microscope can be helpful for
visualization purposes during the foraminotomy. The open-
ing side of the laminoplasty should be placed on the side
of the radiculopathy since this is the side that neuro-
foraminal decompression is easiest. Foraminotomies are
usually done once the lamina is raised and the ligamentum
flavum is removed. Foraminotomy is done by d eroofing the
foramen—that is, removing the superior articular facet of the
caudal segment that covers the foramen, which is generally
the medial third of the facet. This posterior decompression
allows the nerve root to migrate posteriorly, away from the
uncovertebral osteophytes. If a foraminotomy is to be per-
formed on the hinge side, it should be completed before the
laminoplasty to prevent complete disruption of the lamina.
A high-speed burr is used to remove about 50%, medial
to lateral, of the inferior articular facet which overlies the
superior articular facet dorsally. This exposes the ar ticular
surface of the superior articular facet. Thin the facet with
10 Advances in Orthopedics
a combination of cutting and diamond burrs and then a
1 mm Kerrison punch is used to remove the roof of the
foramen, thus exposing the exiting nerve root. Adequate
decompression requires resection of the superior articular
facet overlying the inferior pedicle but not lateral to it, as
this may lead to instability. Verify adequate decompression by
probing the foraminal opening with a nerve hook. The lateral
wall of the superior and inferior pedicles should be easily pal-
pable. Hemostasis is facilitated with gelfoam and thrombin.
13. Fusion
Fusion is indicated with laminoplasty for patients with severe
axial neck pain, evidence of instability, or bilateral radicular
symptoms in addition to myelopathy. If fusion is planned,
the exposure needs to be carried out laterally to the lateral
aspect of the facet joints. Additionally, excision of facet
capsules from C3 to C7 should be performed during the
exposure. After the laminoplasty is complete, place lateral
mass screws at C3 to C7. The start point is 1 mm medial to
the center of the lateral mass with a 15-degree rostral and 30-
degree lateral trajectory [76]. Some prefer a pedicle screw at
C7 for additional stability. After lateral mass decortication,
allograft or cancellous iliac crest autog raft is packed into the
decorticated fusion bed.
14. Wound Closure
After copious irr igation of the wound with normal saline,
retractors are removed, hemostasis is achieved, and a deep
drain is placed. A standard layered closure is then performed.
We close the fascia covering the paravertebral musculature
with a No. 0 vicryl suture in a Figure 8 fashion, followed by
a No. 0 PDS running stitch. The subcutaneous layer is closed
with No. 2-0 vicryl in an interrupted buried fashion. We close
the skin with either a No. 3-0 monocryl suture using a run-
ning subcuticular technique or a No. 3-0 nylon baseball stitch.
15. Postoperative Management
The head of the bed should be kept at greater than 45 degrees
for the first couple days after surgery to minimize venous
bleeding. Patients are immobilized in a rigid cervical collar,
such as an Aspen collar, for 3 -4 weeks. Mobilization with
physical therapy starts on postoperative day one, including
bed transfers and ambulation. We obtain AP and lateral plain
films of the cer vical spine prior to patient discharge. Patients
typically are discharged 24 to 48 hours after surgery and
return for their first follow-up visit 3-4 weeks later, at which
point we obtain repeat AP and lateral cervical spine films. We
encourage patients to return to their day-to-day activities as
soon as possible. At 3-4 weeks, patients can discontinue the
use of their collar and initiate isometric neck exercises.
16. Complications
16.1. Wound Complications. Some argue that wound compli-
cations, such as infection or dehiscence, is a greater risk with
laminoplasty compared to laminectomy as the lamina ar e
rotated and held open [77]. This is an inherent complication
for all posterior cervical approaches due to the strong
muscular attachments. We have found the rate of infection
and dehiscence to be extremely low in our laminoplasty
patients. Avoidance of soft tissue complications is facilitated
by paying meticulous attention to soft tissue handling,
copious irrigation, thorough hemostasis, excision of necrotic
soft tissue prior to closure, a watertight closure, subfascial
drain placement, and perioperative antibiotics.
16.2. Neurolog ic Complications. One of the advantages of
laminoplasty, compared to laminectomy, is the theoretical
decreased risk of neurologic complications as laminoplasty
does not involve placing any instruments between the lamina
and dural sac. Neurologic deterioration is, however, still
a potential risk with laminoplasty. This may be due to
hematoma, inadequate decompression, traumatic surgical
technique, restenosis or persistent stenosis due to inadequate
raising of the lamina, fracture of the hinged lamina, or
closure or dislodgment of the laminar opening [46, 51].
Laminar closure can be related to inadequate stabilization of
the opening or hardware issues, such as broken miniplates.
The incidence of canal restenosis is challenging to ascertain as
CT and MRI scans are not routinely obtained and, when they
are, long-term radiographic assessment of space available for
the cord is rarely reported.
As with laminectomy, nerve roots can be mechanically
injured during laminoplasty procedures, particularly during
decompression with a drill or punch. Isolated nerve root
injuries are a particular concern with laminoplasty, however,
and they occur around five to 11% of the time [4, 20, 78, 79].
This complication presents primarily with motor weakness.
Sensory deficits are a less common presentation. C5 is the
most common nerve root affected. Although C5 palsies
usually present 1–3 days after surgery with deltoid weakness
and shoulder pain, the presentation can occur as late as 20
days postop [80]. It is not clear what causes the C5 nerve
root palsy but some postulate it is related to a traction injury
to the nerve root. Not only are the C5 roots shorter and
less forgiving to traction injuries, C5 is also at the apex of
the lordotic cervical curve and, in general, it is at the
center of the laminoplasty [20, 37, 79–81]. Thus, the cord
drifts posteriorly at C5 moreso than at other levels, which
preferentially stretches the C5 nerve root. Other potential
mechanisms of injury to the C5 nerve root with lamino-
plasty include intraoperative trauma to the C5 ner ve root,
dislodging of the lamina on the hinge side, preoperative
neuroforaminal stenosis not adequately addressed intraoper-
atively, and preexisting spinal cord pathology [20, 78, 81–83].
Some recommend intraoperative transcranial motor evoked
potential and spontaneous EMG monitoring to prevent C5
root injuries by performing a C5 foraminotomy if there are
any abnormal signals to indicate the need to do so.
Treatment of nerve root palsies involves physical therapy
and nonsteroidal anti-inflammatory medication. In general,
complete or near complete recovery from the C5 palsy occurs
spontaneously within one year but it can take up to six
years to recover [37]. Some have recommended pr ophylactic
Advances in Orthopedics 11
foraminotomy and facetectomy to prevent a C5 palsy but this
recommendation has not been borne out in the literature.
16.3. Axial Neck Pain. Thetrueincidenceofaxialneckpain
or stiffness following laminoplasty is variable in the litera-
ture. Yoshida et al., in their series, found that laminoplasty
did not improve or cause neck or shoulder pain [84]. Hosono
et al., however, demonstrated that axial neck pain was present
in 60% of patients following laminoplasty in the postop
period, a significantly higher incidence rate than that of his
anterior fusion patients [66, 84]. This variation in the litera-
ture with regards to the true incidence of post-laminoplasty
axial neck pain is also evidenced by Sani’s meta-analysis
of outcomes in 71 laminoplasty series including more than
2000 patients: he found that postoperative axial neck pain
occurred in anywhere from 6 to 60% of patients and did
not depend on the type of laminoplasty performed [50].
Postoperative neck pain is thought to be related to dissection
around the facets and soft-tissue retraction, necrosis, and
scarring [66, 77]. The neck pain begins in the early postop
period and usually goes away within a year. Preventing
postoperative neck pain and stiffness is the basis for rec-
ommending early neck range of motion. Nonsteroidal anti-
inflammatory medications and physical therapy can be of
benefit, although this has not been studied in the literature.
16.4. Loss of Cervical Motion. Although one advantage of
laminoplasty is that it allows for decompression without
fusion, studies have reported a decrease in cervical range of
motion after laminoplasty. This loss of motion is in the range
of 17–75% but, usually, a global loss of cer vical motion of
approximately 50% is seen [4, 29, 33–37, 41, 46, 48, 49,
53, 55, 85–87]. There is some controversy over the c linical
significance of this loss of cervical motion. Some argue that
range of motion after laminoplasty is crucial to addressing
mechanical stress and avoiding adjacent segment degen-
eration and axial neck pain [47]. On the other hand,
some propose that post-laminoplasty stiffness contributes
to resolution of OPLL, protects the spinal cord by limiting
dynamic motion, and maximizes the potential for neurologic
recovery [41, 51, 88].
16.5. Loss of Cervical Alignment. No laminoplasty technique
can prevent the development of some kyphosis postoper-
atively. The range of worsening cervical alignment in the
literature varies from 22 to 53%, a complication that is not
avoided with fusion [12, 20, 29, 30, 40–51, 88]. There is
a paucity of literature on the correlation between kyphotic
deformity and clinical or neurologic outcomes and even
some data suggesting there is no such correlation [36, 48, 51,
88]. Augmenting a laminoplasty with modern instrumenta-
tion, however, has been shown to help preserve lordosis [6].
17. Clinical Outcomes
Multiple studies have shown that patients with cervical mye-
lopathy due to cervical spondylosis or OPLL do reliably ben-
efit from neurologic improvement following laminoplasty.
Most studies report outcomes using the Japanese Orthopedic
Association (JOA) scoring system, documenting mean preop
and postop scores and rate of recovery. Recovery rates follow-
ing laminoplasty of at least 50–70% are consistently reported
in the literature, though recovery rates as hig h as 90% have
been reported [8, 18, 20, 29, 36, 37, 44, 46, 47, 78, 86, 89–92].
Multiple authors have verified the reliable outcomes of
laminoplasty in the short to midterm, but there only a few
series that have been able to show that improvement in
neurologic status following laminoplasty is maintained in the
long-term. Kawaguchi et al. reviewed long term outcomes
(greater than 10 years) in 133 patients with cervical myelopa-
thy treated with laminoplasty [43]. The average preoperative
JOA score was 9.1 points, and, postoperatively, it improved
to 13.7 within one year. Although he did note some cases
of neurologic decline, postoperative radiculopathy, kyphotic
deformity, and loss of motion, JOA scores and recovery rates
were maintained at 13.4 points and 55% at last followup,
respectively. Seichi et al. performed a long-term retrospective
study looking at the results of double-door laminoplasty in
35 patients with OPLL and 25 patients with CSM, including
5 patients with athetoid cerebral palsy [36]. Average followup
was about 13 years. In 32/35 patients with OPLL and 23/25
patients with CSM, myelopathy improved. Improvements
in JOA scores were maintained at last follow up in 26/35
patients with OPLL and 21/25 patients with CSM. Late
neurologic deterioration occurred in 10 patients with OPLL
at a mean of eight years after surgery and in four patients
with CSM (including 3 patients with athetoid cerebral palsy)
at a mean of 11 years postop. Overall, short-term results
of laminoplasty wer e maintained at 10 years and Seichi’s
group concluded that double-door laminoplasty is a reliable
procedure for patients w ith cervical myelopathy (except in
those with athetoid cerebral palsy).
Neurologic recovery is most likely related more to preop-
erative neurologic status and degree of myelopathy than the
specific laminoplasty technique performed. No significant
difference has been demonstrated with one laminoplasty
technique compared to the other. The etiology of stenosis,
however, does appear to have an effect on prognosis follow-
ing laminoplasty. The benefits of surgery in patients with
CSM appear to last in the long term, but there is a slightly
higher rate of late clinical deterioration in patients with
OPLL. Age greater than 60 and a history of symptoms pre-
operatively for more than one year are also poor prognostic
indicators [42, 78].
There are very few studies directly comparing surgical
options for cervical myelopathy. Kaminsky’s group com-
pared outcomes in patients treated with laminoplasty versus
laminectomy without fusion for CSM using the modified
Nurick grading scale [93]. Both groups improved to a similar
degree. The patients who underwent laminoplasty, however,
had less postoperative cervical pain and less cervical range
of motion. Other earlier studies also found no difference
in long-term neurologic outcomes between patients treated
with laminectomy without fusion and laminoplasty [12, 56,
63]. However, Heller et al. performed a retrospective review
of two matched groups of patients with multilevel cer vical
myelopathy who underwent either laminectomy with fusion
12 Advances in Orthopedics
or laminoplasty [94]. Compared to the laminectomy and
fusion cohort, the laminoplasty cohort showed greater rates
of objective improvement in function as judged by Nurick
scores and greater subjective improvement in strength,
dexterity, sensation, pain, and gait. In addition, no complica-
tions were noted in the laminoplasty cohort compared to 14
complications in nine patients who underwent laminectomy
and fusion. Heller et al. concluded t hat the differences he
found in terms of complications and functional improve-
ment between the two cohorts suggest that laminoplasty may
be more effective and safer than laminectomy with fusion for
multilevel cervical myelopathy.
Edwards et al. compared laminoplasty and anterior de-
compression and fusion in a matched cohort of 1 3 patients
in each group and found higher rates of neurologic improve-
ment, less pain medication needs, and fewer complications in
the laminoplasty cohort [95]. They concluded that though
both multilevel corpectomy and laminoplasty effectively
arrest progression of myelopathy and lead to neurologic
improvement, laminoplasty is a better option. Wada’s group
also retrospectively compared long-term outcomes between
23 patients treated with subtotal corpectomy and 24 patients
treated with laminoplasty for multilevel CSM over 10–14
years [48]. Neurologic recovery was identical between the
two groups and was usually maintained for more than
ten years. However, the subtotal corpectomy group had
longer surgeries, more blood loss, and a 26% pseudarthrosis
rate. Axial pain was significantly more common in the
laminoplasty group compared to the corpectomy group, at
40% and 15%, respectively. Loss of cer vical motion was more
severe in the laminoplasty group as well: range of motion was
29% of what it was preoperatively in this group, compared
to 49% in the corpectomy group. Finally, Yonenobu et al.
also compared the results of 41 patients with CSM under-
going e ither subtotal corpectomy with strut grafting and
42 patients who underwent laminoplasty with a minimum
followup of 2 years [44]. There was no significant difference
in recovery rate and final score in terms of JOA scores. Com-
plications were more frequent in the subtotal corpectomy
group, however, and these were usually due to bone-graft-
related issues. Yonenobu’s group concluded that in terms
of neurologic results, complications, and the potential for
immediate mobilization that laminoplasty affords, it is the
preferred surgical technique for patients with CSM.
18. Conclusion
Laminoplasty is becoming an increasingly popular treatment
for multilevel cervical stenosis due to cervical spondylotic
myelopathy, OPLL, and other causes. Laminoplasty min-
imizes the risk of certain complications associated with
other surgical options, such as graft and fusion-related
complications, postoperative kyphosis and instability, and
the morbidity of an anterior approach. Laminoplasty does
have its own set of potential complications, including
laminar closure, axial neck pain, nerve root palsies, and loss
of cervical motion and alignment. However, laminoplasty
techniques are continuously being refined to address such
potential shortcomings. Indeed, further prospective data
with longer-term followup comparing laminoplasty tech-
niques to other surgical options is necessary. Yet, outcomes
in laminoplasty patients that are at least as good as anterior
decompression and fusion and laminectomy can be expected.
In the appropriate patient and w ith proper surgical tech-
nique, laminoplasty can be an excellent option for patients
with multilevel cervical stenosis and myeloradiculopathy.
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