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Motion Preservation at All Costs? Multilevel Hinge Nonunion, Plate Breakage, and Intradural Plate Migration After Cervical Laminoplasty: A Case Report and Literature Review
Journal Pre-proof Motion preservation at all cost? Multilevel hinge non-union, plate breakage, and intradural plate migration following cervical laminoplasty: a case report and literature review Alexander Rosinski, MS, Khalid Odeh, MD, Jeremi Leasure, MSE, Dimitriy Kondrashov, MD PII:
S1878-8750(19)32912-2
DOI:
https://doi.org/10.1016/j.wneu.2019.11.074
Reference:
WNEU 13743
To appear in:
World Neurosurgery
Received Date: 11 August 2019 Revised Date:
12 November 2019
Accepted Date: 13 November 2019
Please cite this article as: Rosinski A, Odeh K, Leasure J, Kondrashov D, Motion preservation at all cost? Multilevel hinge non-union, plate breakage, and intra-dural plate migration following cervical laminoplasty: a case report and literature review World Neurosurgery (2019), doi: https:// doi.org/10.1016/j.wneu.2019.11.074. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Elsevier Inc. All rights reserved.
Motion preservation at all cost? Multilevel hinge non-union, plate breakage, and intra-dural plate migration following cervical laminoplasty: a case report and literature review 2 Alexander Rosinski, MS 1 Khalid Odeh, MD 1,2 Jeremi Leasure, MSE 1 Dimitriy Kondrashov, MD 1
St. Mary’s Medical Center, San Francisco Orthopaedic Residency Program 450 Stanyan Street San Francisco, CA 94117 USA
2
The Taylor Collaboration 450 Stanyan Street San Francisco, CA 94117 USA Corresponding Author: Jeremi Leasure MSE 450 Stanyan Street San Francisco, CA 94117 (415) 933-6746 [email protected]
Key Words: Laminoplasty, cervical spondylotic myelopathy, non-union Conflict of Interest: No external funding was received for this study. This work has not been previously published or presented. Word Count Abstract: 199 Main Text: 2,603 References: 51 Figures: 5 Tables: 1 Videos: 0
1 1 2 3 4 5
Motion preservation at all cost? Multilevel hinge non-union, plate breakage, and intra-dural plate migration following cervical laminoplasty: a case report and literature review Abstract
6 7
Cervical laminoplasty is a motion-preserving procedure that addresses spinal cord compression
8
and avoids post-laminectomy kyphosis associated with cervical laminectomy. The most common
9
complications include C5 nerve palsy, axial neck pain, hinge non-union, and premature closure.
10
Plating is a relatively newer method of laminoplasty fixation that may provide greater
11
stabilization postoperatively and reduce the risk laminoplasty closure compared to less rigid
12
(e.g., suture) fixation techniques. While prior studies have reported low rates of laminar/lateral
13
mass screw back-out, plate breakage and migration have not been previously described in the
14
literature. The purpose of this article is to present a case of multilevel hinge non-union, plate
15
breakage, and plate fragment migration. Although rare, plate failure may result in a dural tear
16
and spinal cord injury/compression. In this case, a 61-year-old male with a history of cervical
17
spondylotic myelopathy treated with C3-C7 laminoplasty seven years prior presented to our
18
hospital with severe headaches and electrical-type pain through the left upper and lower
19
extremities. Imaging studies revealed several broken laminoplasty plates and intra-dural
20
migration of a fragment of the C7 plate. We provide recommendations for preventing hinge non-
21
union since resultant micro-motion likely contributed to the plate breakages observed in this
22
patient.
23 24 25
2 1 2
Introduction
3 4
The laminoplasty procedure was first developed in 1977 for the treatment of multilevel stenosis
5
due to ossification of the posterior longitudinal ligament (OPLL).1 Since then, laminoplasty has
6
also become a widely-used method of posterior decompression in patients with cervical
7
spondylotic myelopathy (CSM).2 The laminoplasty door may be held open using sutures, bone
8
spacers, or plates using either the Hirabayashi “open door” or the Kurokawa “French door”
9
technique. However, sutures have been associated with premature laminoplasty closure due to
10
cut-out, breakage, or stretching over time.3, 4 Displacement of bone spacers may similarly lead to
11
laminoplasty closure or cord compression if they become dislodged in the spinal canal.5,
12
addition, the hinges must be prepared with enough elastic recoil to compress the graft in place,
13
which may not be achievable in all cases.7 Laminoplasty plates have therefore become
14
increasingly popular because of the immediate stability that they provide postoperatively.2
6
In
15 16
Revision rates after laminoplasty are relatively low and range from 0-11% at 5-10 years
17
following surgery.8,
18
laminoplasty closure4,
19
displacement of the lamina into the spinal canal have also been reported.3, 12-15 However, no prior
20
studies have described the incidence and subsequent management of laminoplasty plate breakage
21
and/or displacement. In a prospective clinical study of 54 “plate-only” open door laminoplasties,
22
laminar screw back-out was seen in 2.3% of 217 plated levels, but none of these resulted in plate
23
failure at 12 months of follow-up.7 It is possible that longer follow-up is needed to detect plate
9
Technique-related factors that may lead to revision surgery include 10
and post-laminectomy kyphosis.11 Cases of hinge fracture with
3 1
fractures. Liu et al similarly found low rates of screw back-out, no instances of plate
2
dislodgement, and relatively higher rates of screw back-out at the most cranial and caudal levels
3
of the laminoplasty.16
4 5
The purpose of this article is to describe a case of multilevel hinge non-union, diffuse plate
6
breakage, and plate fragment migration into the dura that presented seven years after
7
laminoplasty. The following case report may help guide and inform the surgical management of
8
laminoplasty plate failures as this complication is rare and infrequently discussed in the
9
literature. We have performed a literature review on late complications of cervical laminoplasty
10
and provide recommendations for preventing hinge non-union since prolonged hinge instability
11
likely contributes to plate breakage. We also propose obtaining postoperative radiographs at
12
medium and long-term follow-up to detect hardware failure.
13 14
Case Report
15 16
A 61-year-old male musician with a history of CSM treated with C3-C7 open-door cervical
17
laminoplasty (Figure 1) seven years prior presented to our hospital with severe, intractable
18
headaches of one month’s duration. He also reported electrical-type pain through the left arm,
19
buttock, and thigh. No hinge fractures occurred at the time of the patient’s laminoplasty and
20
there were no surgical complications. On physical examination, there was slight hyperreflexia in
21
both upper extremities. His left straight leg raise reproduced a Lhermitte’s type sign, with
22
electricity running through the left side of his entire body. The remainder of his exam was
23
unremarkable. While subsequent imaging demonstrated no evidence of intra-cranial aneurysm or
4 1
hemorrhage, a spinal tap revealed red blood cells in the cerebrospinal fluid (CSF). Computed
2
tomography (CT) of the cervical spine showed several broken laminoplasty plates (C4, C6, and
3
C7), including intra-dural migration of a fragment of the C7 plate (Figure 2). The severe
4
headaches were attributed to local damage from the plate fragments and blood within
5
subarachnoid space as well as possible CSF leakage. There was also hinge non-union at C5, C6,
6
and C7 (Figure 3). The patient consented to urgent spinal decompression and revision
7
laminectomy and fusion.
8 9
Surgical Treatment
10 11
A standard posterior approach to the sub-axial spine was performed. Plate breakage was
12
confirmed at C4, C6, and C7. Each of these laminoplasty plates was broken in more than two
13
places. Stable hinge union was observed on the right side at C3 and C4. There was a 7-mm dural
14
defect and CSF leakage at the medial edge of the C7 lateral mass. A fragment of the C7 plate
15
was found in the dorsal part of the dura immediately adjacent to the spinal cord along with a
16
dural defect (Figure 2). Each laminoplasty plate was carefully removed, and the dura was
17
repaired with a dural patch and sealant since it was not amenable to primary repair.
18
Laminectomy and fusion was then performed at C5-C7 (Figure 4). The patient’s postoperative
19
course was uneventful. His headaches and left-sided shooting pain have resolved completely. At
20
latest follow-up, he had some residual neck pain when rotating his head to the left but was
21
otherwise asymptomatic.
22 23
Discussion
5 1 2
Recent trends in cervical laminoplasty include muscle sparing techniques, restriction of the
3
laminoplasty to the C3-C6 vertebrae, and prophylactic foraminotomy for the prevention of C5
4
nerve palsy.2 In addition, laminoplasty plates have become increasingly popular.17 In a recent
5
systematic review, over 50% of laminoplasty studies investigated the use of miniplates and
6
screws.2 In a similar review published 10 years earlier, only 6% of articles reported clinical
7
outcomes of miniplates.18 The advantages of laminoplasty plates include immediate
8
postoperative stability allowing for early range of motion, decreased need for postoperative
9
bracing, lower risk of premature laminoplasty closure, and greater stabilization of excessively
10
thinned hinges.7 Maeda et al demonstrated that early range of motion and limited soft collar use
11
may prevent cervical stiffness and the development of postoperative kyphosis.19 Other studies
12
suggest that the incidence of axial pain is lower in patients treated with miniplates compared to
13
less rigid fixation techniques20, 21, although this is controversial.22, 23 Nevertheless, plate breakage
14
and migration may represent an under-reported and under-recognized complication in the
15
laminoplasty literature. Although rare, the consequences of iatrogenic spinal cord lesions can be
16
devastating.6 The purpose of this case report was to describe the diagnosis and treatment of
17
multilevel hinge non-union, plate breakage, and intra-dural plate fragment migration after
18
cervical laminoplasty. We also recommend that the hinge width be optimized using a burr no
19
larger than 2 mm to avoid intra-operative hinge fracture and postoperative hinge non-union.
20 21
Previous authors have identified three main categories of laminoplasty failures: “technique
22
related” (with new, early-onset postoperative symptoms), “inadequate treatment” (characterized
23
by residual preoperative symptoms), and “disease progression” (in which new, late-onset
6 1
postoperative symptoms develop).8,
24
2
recommendations for their prevention and treatment are summarized in Table 1. The most
3
common reason for revision surgery is recurrence or worsening of symptoms due to disease
4
progression either within or adjacent to the laminoplasty levels.8 Although laminoplasty is a
5
motion-preserving procedure, previous authors have reported decreased range of motion and
6
altered spinal biomechanics which may contribute to adjacent segment degeneration.25, 26 In a
7
retrospective review of 237 patients who underwent laminoplasty for CSM, Shigematsu et al
8
reported five cases of revision surgery due to laminoplasty closure (n=2), adjacent segment
9
degeneration (n=2), and foraminal stenosis (n=1).24 Revision surgery included laminectomy,
10
repeat laminoplasty, or foraminotomy based on the site(s) of compression, sagittal alignment of
11
the cervical spine, general condition of the patient, and surgeon preference. In a retrospective
12
study of 130 patients with CSM and OPLL, 25% of revisions were performed due to
13
laminoplasty closure and re-stenosis of treated levels at 3 years postoperatively.8 The
14
laminoplasty door was held open by suture anchors in each case and there were no closures
15
observed in patients treated with plate fixation. The authors report that each laminoplasty closure
16
was treated successfully with laminectomy and fusion, while patients with inadequate symptom
17
relief and disease progression were primarily treated with anterior cervical discectomy and
18
fusion (ACDF).
Late complications associated with laminoplasty and
19 20
An anterior approach may be considered in laminoplasty patients requiring revision surgery due
21
to loss of lordotic alignment and anterior compressive pathology such as progression of OPLL
22
and/or disc herniation.27 Although laminoplasty achieves significant spinal canal expansion
23
posteriorly,28 anterior compression may still be present postoperatively due to technique-related
7 1
factors such as inadequate opening angle.8, 27, 29 Furthermore, OPLL progression occurs in most
2
patients following laminoplasty and averages 9 mm in the longitudinal axis and 1.3 mm in
3
anterior-posterior axis at 10 years of follow up.30 Previous studies also suggest that ACDF may
4
be preferable to laminoplasty in cases where OPLL occupies more than 60% of the spinal canal
5
or is thicker than 7 mm preoperatively.31,
6
cases due to persistent anterior compression and cervical instability, revision ACDF with
7
autogenous fibular strut graft achieved significant improvements in clinical outcomes including
8
reductions in radicular and axial neck pain.27 Circumferential fusion has also been used in
9
revision laminoplasty patients at high risk for non-union and instrumentation failure due to spinal
10
deformity and poor neck control.8 Based on prior studies, we recommend anterior approaches for
11
laminoplasty revision surgery in cases of large anterior cord compression, cervical instability and
12
loss of lordotic alignment, and OPLL involving more than 60% of the spinal canal.
32
In a retrospective analysis of failed laminoplasty
13 14
Additional postoperative complications associated with cervical laminoplasty include screw
15
back-out, hinge non-union, and delayed (or postoperative) hinge fracture. Liu et al and Rhee et al
16
investigated the incidence and clinical significance of screw back-out following plate
17
laminoplasty and found no associated cases of plate failure, laminoplasty closure, or clinical
18
symptoms.7, 16 However, follow up in each study was limited to 1-2 years and it is possible that
19
longer follow-up is needed to detect plate failures. Screw back-out appears to not cause
20
significant clinical problems in the early postoperative period but may eventually lead to
21
laminoplasty plate failure as seen in our case report. While delayed hinge fracture may contribute
22
to postoperative axial neck pain or cause significant spinal cord compression and neurologic
23
deficits, hinge fractures heal within 1-2 years in most cases.7, 23, 33 As a result, some authors have
8 1
recommended careful follow up without the need for additional surgical intervention such as
2
conversion to laminectomy and fusion.34
3 4
Although few biomechanical studies on laminoplasty plate fixation strength exist, hinge non-
5
union likely contributed to the plate breakages observed in our patient. “Floppy” hinges may
6
decrease the stability of the laminae, thus producing increased strain on the laminoplasty plates
7
and eventual breakage. While the mechanisms of plate failure have not been investigated, a
8
biomechanical study by Tadepalli et al demonstrated that cervical cadaveric vertebrae treated
9
with open door laminoplasty plates fail at the hinge under both direct compressive and
10
parasagittal loading.35 Finite element analysis revealed that the peak stresses in the laminoplasty
11
plates were far below the yield strength of titanium alloy, and therefore neither screw pull-out
12
nor plate failure was observed during cadaveric load to failure testing. While the loading
13
conditions tested in this study reflect the stability of the laminoplasty to resist laminar closure,
14
cranio-caudal compression also results in hinge failure and is more relevant to patients treated
15
with muscle-sparing techniques (due to intact extensor function).36 Furthermore, laminoplasty
16
plates are notably smaller than most plates used in the spine and extremities. Since laminoplasty
17
is a motion-preserving procedure, these plates are subjected to repetitive stress with each cycle of
18
motion. In our patient’s case, multiple hinge non-unions were observed at the C5-C7 vertebra
19
and plate breakage was seen at C4, C6, and C7. While the C4 hinge was deemed stable
20
intraoperatively, hinge non-union likely increased the strain on the C6 and C7 plates and
21
contributed to their failure.
22
9 1
In addition, over-resection of the ventral cortex may have contributed to hinge non-union and
2
subsequent plate breakage. Previous studies have identified risk factors for hinge fracture such as
3
medially placed hinge gutters and involvement of the C3-C5 surgical levels (due to relatively
4
thinner laminae medially and compared to the C6 and C7 vertebrae).23, 37 Medially placed gutters
5
also require increased opening angles to achieve the same level of laminar elevation. Hinge
6
fracture may occur during laminar elevation if too little bone has been removed.38 Alternatively,
7
removal of too much ventral cortex may result in an unstable “floppy” hinge and delayed
8
fracture, which may result in spinal cord compression due to intrusion of the fractured lamina
9
into the spinal canal.14, 15 The pliability and stiffness of the greenstick deformation are assessed
10
intraoperatively to prevent either mechanism of failure. Despite these surgical precautions,
11
trough creation can be technically difficult and reported rates of non-union range from 2-16%.7,
12
13, 33, 39
13
laminoplasty troughs. Some authors have recommended a 2-mm acorn-shaped burr for trough
14
creation to limit hinge width.40 Increased bone gaps may also adversely affect bony healing,
15
especially if a delayed fracture occurs.33 We recommend a 2-mm burr for more consistent
16
preservation of the ventral cortex and creation of smaller bone gaps, as demonstrated in Figure 5.
17
Furthermore, a color change in the cortex may be appreciated while creating hinges.41 As the
18
ventral cortex thins, yellow and blue areas corresponding to the ligamentum flavum and dural
19
veins may be visualized through the bone. In the event of intraoperative hinge instability, salvage
20
plates can be used to fix the lamina to the lateral mass.41 Some surgeons routinely bone graft the
21
hinge side with local autograft.42
22
Of note, a high-speed burr with a 3-mm M8 diamond tip was used to create our patient’s
10 1
One limitation of this case report is that we lacked interval imaging between the patient’s initial
2
laminoplasty procedure and his revision surgery 7 years later. Therefore, the timeline of hinge
3
non-union and plate breakage is largely unknown. Previous studies suggest that hinge fractures
4
most often occur in the early postoperative period (within 4 months of surgery), although the
5
majority remain stable for up to 2 years.23 Furthermore, Park et al reported that patients with
6
three or more hinge fractures had significantly worse pain and disability scores compared with
7
two or less.23 Other studies suggest no difference in clinical outcomes between patients with and
8
without hinge non-union.43
9 10
Conclusion
11 12
We report a rare case of multiple laminoplasty hinge non-union, plate breakage, and intra-dural
13
plate fragment migration. Care must be taken to avoid over-resection of the ventral cortex during
14
laminoplasty. We also recommend a 2-mm burr to limit hinge width and reduce the dorsal bone
15
gap. Hinge non-union may result in laminar instability and produce increased strain on the
16
laminoplasty plate. Intra-dural fragment migration and symptomatic spinal cord compression are
17
possible complications of plate failure. In this case, urgent plate removal and laminectomy was
18
successful and the patient’s symptoms resolved completely.
19 20 21 22 23 24 25 26 27 28
11 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Table 1. Literature review of late postoperative complications associated with cervical laminoplasty Complication Progression of disease (OPLL, CSM)8, 24, 26
Laminoplasty closure3, 10, 24
Delayed hinge fracture14, 15
Laminoplasty screw back-out7, 16
Hydroxyapatite spacer displacement and dural laceration5, 6, 33 Postoperative kyphosis18
Recommendations for prevention and treatment • Revision surgery depending on the site(s) of compression, sagittal alignment of the cervical spine, general condition of the patient, and surgeon preference.24, 27 • Anterior approaches for cases of large anterior cord compression, loss of lordotic alignment, and OPLL involving more than 60% of the spinal canal.8, 27, 31, 32 • Use of laminoplasty spacers or plates in patients at high risk of closure (e.g., decreased lordosis, OPLL).7, 44 • Treatment often includes repeat laminoplasty or revision laminectomy.3, 24 • Use of a 2- or 3-mm burr to avoid excessive removal of ventral cortex.40, 45 • Avoidance of medially placed hinge gutters on the opening side.23, 46 • Frequent checks of hinge stability intraoperatively.23 • Careful follow up with postoperative CT scans.13 • Use of two laminar screws.7 • Retightening of the first screw after placement of the second screw.16 • Use of longer (7 mm) screws to increase bone purchase.16 • Judicial dissection at the proximal and distal ends of the laminoplasty construct.16 • Placement of spacers at the base of the spinous process.47 • Spinous process splitting using a thread-wire saw.5 • Use of mini-plate fixation.48, 49 • Restriction of the laminoplasty from C3-C6.50 • Use of muscle/posterior element-sparing techniques.2
12
Postoperative loss of ROM
25, 26
• • •
Early range of motion and limited soft collar use.19, 51 Use of muscle/posterior element-sparing techniques.2 Early range of motion and limited soft collar use.19, 51
1 2 3 4 5
Figures
6 7
Figure 1. Postoperative sagittal radiograph of the cervical spine following open-door
8
laminoplasty from C3-C7. Four 10-mm and one 12-mm Centerpiece Medtronic Sofamor Danek
9
plates were used. There were no complications and the patient recovered well from surgery.
10 11
Figure 2. Axial (A) and sagittal (B) T2-weighted MRI views of the cervical spine demonstrating
12
intra-dural migration of a fragment of the C7 plate immediately adjacent to the left spinal cord.
13
(C) Axial CT of the cervical spine showing intra-dural migration of a fragment of the C7 plate.
14
(D) Intraoperative photos of the C7 plate fragment in the dorsal dura at the medial edge of the C7
15
lateral mass (black arrow – plate fragment, white arrow – dural defect with spinal cord visible).
16 17
Figure 3. Axial CT views demonstrating hinge union at C4 (A) and hinge non-union at C7 (B).
18
Hinge healing is complete when both the ventral and dorsal cortices are bridged with bone 7, as
19
seen in (A).
20 21
Figure 4. Anteroposterior (A) and lateral (B) radiographs of the cervical spine following C5-C7
22
laminectomy and fusion.
13 1 2
Figure 5. Pictures demonstrating the difference between the use of a 4-mm burr (left column) vs.
3
2-mm burr for creation of the trough and opening hinge in a C5 cervical spine bone model. A 1-
4
cm spacer was inserted into the opening wedge.
5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
References 1. 2. 3.
4. 5.
6.
7.
8.
9.
10.
11.
Hirabayashi K, Watanabe K, Wakano K, Suzuki N, Satomi K, Ishii Y. Expansive open-door laminoplasty for cervical spinal stenotic myelopathy. Spine. Oct 1983;8(7):693-699. Duetzmann S, Cole T, Ratliff JK. Cervical laminoplasty developments and trends, 20032013: a systematic review. Journal of neurosurgery. Spine. Jul 2015;23(1):24-34. Satomi K, Ogawa J, Ishii Y, Hirabayashi K. Short-term complications and long-term results of expansive open-door laminoplasty for cervical stenotic myelopathy. The spine journal : official journal of the North American Spine Society. Jan-Feb 2001;1(1):26-30. Morio M, Kota W, Takashi T, et al. Risk factors for closure of lamina after open-door laminoplasty. Journal of Neurosurgery: Spine SPI. 2008;9(6):530-537. Ono A, Yokoyama T, Numasawa T, Wada K, Toh S. Dural damage due to a loosened hydroxyapatite intraspinous spacer after spinous process–splitting laminoplasty. 2007;7(2):230. Kanemura A, Doita M, Iguchi T, Kasahara K, Kurosaka M, Sumi M. Delayed dural laceration by hydroxyapatite spacer causing tetraparesis following double-door laminoplasty. 2008;8(2):121. Rhee JM, Register B, Hamasaki T, Franklin B. Plate-only open door laminoplasty maintains stable spinal canal expansion with high rates of hinge union and no plate failures. Spine. Jan 1 2011;36(1):9-14. Liu G, Buchowski JM, Bunmaprasert T, Yeom JS, Shen H, Riew KD. Revision surgery following cervical laminoplasty: etiology and treatment strategies. Spine. Dec 1 2009;34(25):2760-2768. Veeravagu A, Azad TD, Zhang M, et al. Outcomes of cervical laminoplasty—Populationlevel analysis of a national longitudinal database. Journal of Clinical Neuroscience. 2018/02/01/ 2018;48:66-70. Tamai K, Suzuki A, Terai H, Toyoda H, Hoshino M, Nakamura H. Laminar closure after expansive open-door laminoplasty: fixation methods and cervical alignments impact on the laminar closure and surgical outcomes. The Spine Journal. 2016/09/01/ 2016;16(9):1062-1069. Suk KS, Kim KT, Lee JH, Lee SH, Lim YJ, Kim JS. Sagittal alignment of the cervical spine after the laminoplasty. Spine. Nov 1 2007;32(23):E656-660.
14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44
12.
13.
14.
15. 16. 17.
18. 19.
20.
21.
22. 23.
24.
25. 26.
27.
Lee JH, Chough CK. Risk Factors for Hinge Fracture Associated with Surgery Following Cervical Open-Door Laminoplasty. Korean journal of neurotrauma. Oct 2018;14(2):118122. Lee D-H, Kim H, Lee CS, Hwang C-J, Cho J-H, Cho SK. Clinical and radiographic outcomes following hinge fracture during open-door cervical laminoplasty. Journal of Clinical Neuroscience. 2017/09/01/ 2017;43:72-76. Yonenobu K, Oda T. Posterior approach to the degenerative cervical spine. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society. Oct 2003;12 Suppl 2:S195-201. Hosono N, Sakaura H, Mukai Y, Ishii T, Yoshikawa H. En bloc laminoplasty without dissection of paraspinal muscles. Journal of neurosurgery. Spine. Jul 2005;3(1):29-33. Liu G, Buchowski JM, Riew KD. Screw Back-Out Following "Open-Door" Cervical Laminoplasty: A Review of 165 Plates. Asian spine journal. 2015;9(6):849-854. Park AE, Heller JG. Cervical laminoplasty: use of a novel titanium plate to maintain canal expansion--surgical technique. Journal of spinal disorders & techniques. Aug 2004;17(4):265-271. Ratliff JK, Cooper PR. Cervical laminoplasty: a critical review. Journal of neurosurgery. Apr 2003;98(3 Suppl):230-238. Maeda T, Arizono T, Saito T, Iwamoto Y. Cervical alignment, range of motion, and instability after cervical laminoplasty. Clinical Orthopaedics and Related Research. 2002(401):132-138. Dimar JR, 2nd, Bratcher KR, Brock DC, Glassman SD, Campbell MJ, Carreon LY. Instrumented open-door laminoplasty as treatment for cervical myelopathy in 104 patients. American journal of orthopedics (Belle Mead, N.J.). Jul 2009;38(7):E123-128. Chen H, Liu H, Zou L, et al. Effect of Mini-plate Fixation on Hinge Fracture and Bony Fusion in Unilateral Open-door Cervical Expansive Laminoplasty. Clinical spine surgery. Jul 2016;29(6):E288-295. Jiang L, Chen W, Chen Q, Xu K, Wu Q, Li F. Clinical application of a new plate fixation system in open-door laminoplasty. Orthopedics. 2012;35(2):e225-e231. Park YK, Lee DY, Hur JW, Moon HJ. Delayed hinge fracture after plate-augmented, cervical open-door laminoplasty and its clinical significance. The spine journal : official journal of the North American Spine Society. Jul 1 2014;14(7):1205-1213. Shigematsu H, Koizumi M, Matsumori H, et al. Revision surgery after cervical laminoplasty: report of five cases and literature review. The spine journal : official journal of the North American Spine Society. Jun 1 2015;15(6):e7-13. Seichi A, Takeshita K, Ohishi I, et al. Long-term results of double-door laminoplasty for cervical stenotic myelopathy. Spine. Mar 1 2001;26(5):479-487. Chiba K, Ogawa Y, Ishii K, et al. Long-term results of expansive open-door laminoplasty for cervical myelopathy--average 14-year follow-up study. Spine. Dec 15 2006;31(26):2998-3005. Komura S, Miyamoto K, Hosoe H, et al. Anterior cervical multilevel decompression and fusion using fibular strut as revision surgery for failed cervical laminoplasty. Archives of Orthopaedic and Trauma Surgery. September 01 2011;131(9):1177-1185.
15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43
28.
29. 30.
31.
32.
33.
34.
35.
36.
37.
38. 39. 40. 41. 42.
Takahashi Y, Narusawa K, Shimizu K, Hijioka A, Nakamura T. Enlargement of cervical spinal cord correlates with improvement of motor function in upper extremities after laminoplasty for cervical myelopathy. Journal of spinal disorders & techniques. May 2006;19(3):194-198. Yuan W, Zhu Y. Posterior Revision Surgery for Cervical Open-Door Laminoplasty Because of Poor Expansion of the Spinal Canal. World Neurosurg. Oct 2019;130:e90-e97. Kawaguchi Y, Kanamori M, Ishihara H, et al. Progression of ossification of the posterior longitudinal ligament following en bloc cervical laminoplasty. The Journal of bone and joint surgery. American volume. Dec 2001;83(12):1798-1802. Iwasaki M, Okuda S, Miyauchi A, et al. Surgical strategy for cervical myelopathy due to ossification of the posterior longitudinal ligament: Part 2: Advantages of anterior decompression and fusion over laminoplasty. Spine. Mar 15 2007;32(6):654-660. Yamazaki A, Homma T, Uchiyama S, Katsumi Y, Okumura H. Morphologic limitations of posterior decompression by midsagittal splitting method for myelopathy caused by ossification of the posterior longitudinal ligament in the cervical spine. Spine. Jan 1 1999;24(1):32-34. Tanaka N, Nakanishi K, Fujimoto Y, et al. Expansive laminoplasty for cervical myelopathy with interconnected porous calcium hydroxyapatite ceramic spacers: comparison with autogenous bone spacers. Journal of spinal disorders & techniques. Dec 2008;21(8):547552. Lee DH, Kim H, Lee CS, Hwang CJ, Cho JH, Cho SK. Clinical and radiographic outcomes following hinge fracture during open-door cervical laminoplasty. Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia. Sep 2017;43:72-76. Tadepalli SC, Gandhi AA, Fredericks DC, Grosland NM, Smucker J. Cervical laminoplasty construct stability: an experimental and finite element investigation. The Iowa orthopaedic journal. 2011;31:207-214. Ohara Y, Hara T, Orías AAE, Tani S, Inoue N, Mizuno J. In vitro biomechanical evaluation of a monocoque plate-spacer construct for cervical open-door laminoplasty. PloS one. 2018;13(10):e0204147-e0204147. Hur JW, Park YK, Kim BJ, Moon HJ, Kim JH. Risk Factors for Delayed Hinge Fracture after Plate-Augmented Cervical Open-Door Laminoplasty. Journal of Korean Neurosurgical Society. Jul 2016;59(4):368-373. Thakur NA, Heller JG. Cervical laminoplasty: Review of complications and strategies to avoid them. Seminars in Spine Surgery. 2013/09/01/ 2013;25(3):209-213. Lee S, Chung CK, Kim CH. Risk factor analysis of hinge fusion failure after plate-only open-door laminoplasty. Global spine journal. Feb 2015;5(1):9-16. Lehman RA, Jr., Taylor BA, Rhee JM, Riew KD. Cervical laminaplasty. The Journal of the American Academy of Orthopaedic Surgeons. Jan 2008;16(1):47-56. Leckie SK, Kercher JS, Yoon ST. Cervical Laminoplasty. In: Rhee JM, ed. Operative Techniques in Spine Surgery. Philadelphia: Wolters Kluwer; 2016:27-35. Onuma H, Hirai T, Yoshii T, et al. Clinical and radiologic outcomes of bone grafted and non-bone grafted double-door laminoplasty, the modified Kirita-Miyazaki method, for
16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
43.
44.
45. 46.
47.
48.
49.
50.
51.
treatment of cervical spondylotic myelopathy: Five-year follow-up. Journal of Orthopaedic Science. 2018/11/01/ 2018;23(6):923-928. Cho SH, Lee JH, Chough CK, et al. Hinge Fracture during Cervical Open-door Laminoplasty: Does it Affect Clinical and Radiographic Outcomes? Korean Journal of Spine. Jun 2014;11(2):45-51. Matsumoto M, Watanabe K, Hosogane N, et al. Impact of lamina closure on long-term outcomes of open-door laminoplasty in patients with cervical myelopathy: minimum 5year follow-up study. Spine. Jul 1 2012;37(15):1288-1291. Kawaguchi Y, Matsui H, Ishihara H, Gejo R, Yoshino O. Axial symptoms after en bloc cervical laminoplasty. Journal of spinal disorders. Oct 1999;12(5):392-395. Satomi K, Nishu Y, Kohno T, Hirabayashi K. Long-term follow-up studies of open-door expansive laminoplasty for cervical stenotic myelopathy. Spine. Mar 1 1994;19(5):507510. Kaito T, Hosono N, Makino T, Kaneko N, Namekata M, Fuji T. Postoperative displacement of hydroxyapatite spacers implanted during double-door laminoplasty. Journal of neurosurgery. Spine. Jun 2009;10(6):551-556. Goto T, Ohata K, Takami T, et al. Hydroxyapatite laminar spacers and titanium miniplates in cervical laminoplasty. Journal of neurosurgery. Oct 2002;97(3 Suppl):323329. Tanaka S, Tashiro T, Gomi A, Ujiie H. Cervical unilateral open-door laminoplasty with titanium miniplates through newly designed hydroxyapatite spacers. Neurologia medico-chirurgica. 2011;51(9):673-677. Sakaura H, Hosono N, Mukai Y, Iwasaki M, Yoshikawa H. Medium-term outcomes of C36 laminoplasty for cervical myelopathy: a prospective study with a minimum 5-year follow-up. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society. Jun 2011;20(6):928-933. Kimura A, Seichi A, Inoue H, Hoshino Y. Long-term results of double-door laminoplasty using hydroxyapatite spacers in patients with compressive cervical myelopathy. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society. 2011;20(9):1560-1566.
cm – Centimeters CSF - cerebrospinal fluid CSM - cervical spondylotic myelopathy CT - computed tomography MRI - Magnetic Resonance Imaging mm - Millimeters OPLL - ossification of the posterior longitudinal ligament
S1878-8750(19)32912-2
DOI:
https://doi.org/10.1016/j.wneu.2019.11.074
Reference:
WNEU 13743
To appear in:
World Neurosurgery
Received Date: 11 August 2019 Revised Date:
12 November 2019
Accepted Date: 13 November 2019
Please cite this article as: Rosinski A, Odeh K, Leasure J, Kondrashov D, Motion preservation at all cost? Multilevel hinge non-union, plate breakage, and intra-dural plate migration following cervical laminoplasty: a case report and literature review World Neurosurgery (2019), doi: https:// doi.org/10.1016/j.wneu.2019.11.074. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Elsevier Inc. All rights reserved.
Motion preservation at all cost? Multilevel hinge non-union, plate breakage, and intra-dural plate migration following cervical laminoplasty: a case report and literature review 2 Alexander Rosinski, MS 1 Khalid Odeh, MD 1,2 Jeremi Leasure, MSE 1 Dimitriy Kondrashov, MD 1
St. Mary’s Medical Center, San Francisco Orthopaedic Residency Program 450 Stanyan Street San Francisco, CA 94117 USA
2
The Taylor Collaboration 450 Stanyan Street San Francisco, CA 94117 USA Corresponding Author: Jeremi Leasure MSE 450 Stanyan Street San Francisco, CA 94117 (415) 933-6746 [email protected]
Key Words: Laminoplasty, cervical spondylotic myelopathy, non-union Conflict of Interest: No external funding was received for this study. This work has not been previously published or presented. Word Count Abstract: 199 Main Text: 2,603 References: 51 Figures: 5 Tables: 1 Videos: 0
1 1 2 3 4 5
Motion preservation at all cost? Multilevel hinge non-union, plate breakage, and intra-dural plate migration following cervical laminoplasty: a case report and literature review Abstract
6 7
Cervical laminoplasty is a motion-preserving procedure that addresses spinal cord compression
8
and avoids post-laminectomy kyphosis associated with cervical laminectomy. The most common
9
complications include C5 nerve palsy, axial neck pain, hinge non-union, and premature closure.
10
Plating is a relatively newer method of laminoplasty fixation that may provide greater
11
stabilization postoperatively and reduce the risk laminoplasty closure compared to less rigid
12
(e.g., suture) fixation techniques. While prior studies have reported low rates of laminar/lateral
13
mass screw back-out, plate breakage and migration have not been previously described in the
14
literature. The purpose of this article is to present a case of multilevel hinge non-union, plate
15
breakage, and plate fragment migration. Although rare, plate failure may result in a dural tear
16
and spinal cord injury/compression. In this case, a 61-year-old male with a history of cervical
17
spondylotic myelopathy treated with C3-C7 laminoplasty seven years prior presented to our
18
hospital with severe headaches and electrical-type pain through the left upper and lower
19
extremities. Imaging studies revealed several broken laminoplasty plates and intra-dural
20
migration of a fragment of the C7 plate. We provide recommendations for preventing hinge non-
21
union since resultant micro-motion likely contributed to the plate breakages observed in this
22
patient.
23 24 25
2 1 2
Introduction
3 4
The laminoplasty procedure was first developed in 1977 for the treatment of multilevel stenosis
5
due to ossification of the posterior longitudinal ligament (OPLL).1 Since then, laminoplasty has
6
also become a widely-used method of posterior decompression in patients with cervical
7
spondylotic myelopathy (CSM).2 The laminoplasty door may be held open using sutures, bone
8
spacers, or plates using either the Hirabayashi “open door” or the Kurokawa “French door”
9
technique. However, sutures have been associated with premature laminoplasty closure due to
10
cut-out, breakage, or stretching over time.3, 4 Displacement of bone spacers may similarly lead to
11
laminoplasty closure or cord compression if they become dislodged in the spinal canal.5,
12
addition, the hinges must be prepared with enough elastic recoil to compress the graft in place,
13
which may not be achievable in all cases.7 Laminoplasty plates have therefore become
14
increasingly popular because of the immediate stability that they provide postoperatively.2
6
In
15 16
Revision rates after laminoplasty are relatively low and range from 0-11% at 5-10 years
17
following surgery.8,
18
laminoplasty closure4,
19
displacement of the lamina into the spinal canal have also been reported.3, 12-15 However, no prior
20
studies have described the incidence and subsequent management of laminoplasty plate breakage
21
and/or displacement. In a prospective clinical study of 54 “plate-only” open door laminoplasties,
22
laminar screw back-out was seen in 2.3% of 217 plated levels, but none of these resulted in plate
23
failure at 12 months of follow-up.7 It is possible that longer follow-up is needed to detect plate
9
Technique-related factors that may lead to revision surgery include 10
and post-laminectomy kyphosis.11 Cases of hinge fracture with
3 1
fractures. Liu et al similarly found low rates of screw back-out, no instances of plate
2
dislodgement, and relatively higher rates of screw back-out at the most cranial and caudal levels
3
of the laminoplasty.16
4 5
The purpose of this article is to describe a case of multilevel hinge non-union, diffuse plate
6
breakage, and plate fragment migration into the dura that presented seven years after
7
laminoplasty. The following case report may help guide and inform the surgical management of
8
laminoplasty plate failures as this complication is rare and infrequently discussed in the
9
literature. We have performed a literature review on late complications of cervical laminoplasty
10
and provide recommendations for preventing hinge non-union since prolonged hinge instability
11
likely contributes to plate breakage. We also propose obtaining postoperative radiographs at
12
medium and long-term follow-up to detect hardware failure.
13 14
Case Report
15 16
A 61-year-old male musician with a history of CSM treated with C3-C7 open-door cervical
17
laminoplasty (Figure 1) seven years prior presented to our hospital with severe, intractable
18
headaches of one month’s duration. He also reported electrical-type pain through the left arm,
19
buttock, and thigh. No hinge fractures occurred at the time of the patient’s laminoplasty and
20
there were no surgical complications. On physical examination, there was slight hyperreflexia in
21
both upper extremities. His left straight leg raise reproduced a Lhermitte’s type sign, with
22
electricity running through the left side of his entire body. The remainder of his exam was
23
unremarkable. While subsequent imaging demonstrated no evidence of intra-cranial aneurysm or
4 1
hemorrhage, a spinal tap revealed red blood cells in the cerebrospinal fluid (CSF). Computed
2
tomography (CT) of the cervical spine showed several broken laminoplasty plates (C4, C6, and
3
C7), including intra-dural migration of a fragment of the C7 plate (Figure 2). The severe
4
headaches were attributed to local damage from the plate fragments and blood within
5
subarachnoid space as well as possible CSF leakage. There was also hinge non-union at C5, C6,
6
and C7 (Figure 3). The patient consented to urgent spinal decompression and revision
7
laminectomy and fusion.
8 9
Surgical Treatment
10 11
A standard posterior approach to the sub-axial spine was performed. Plate breakage was
12
confirmed at C4, C6, and C7. Each of these laminoplasty plates was broken in more than two
13
places. Stable hinge union was observed on the right side at C3 and C4. There was a 7-mm dural
14
defect and CSF leakage at the medial edge of the C7 lateral mass. A fragment of the C7 plate
15
was found in the dorsal part of the dura immediately adjacent to the spinal cord along with a
16
dural defect (Figure 2). Each laminoplasty plate was carefully removed, and the dura was
17
repaired with a dural patch and sealant since it was not amenable to primary repair.
18
Laminectomy and fusion was then performed at C5-C7 (Figure 4). The patient’s postoperative
19
course was uneventful. His headaches and left-sided shooting pain have resolved completely. At
20
latest follow-up, he had some residual neck pain when rotating his head to the left but was
21
otherwise asymptomatic.
22 23
Discussion
5 1 2
Recent trends in cervical laminoplasty include muscle sparing techniques, restriction of the
3
laminoplasty to the C3-C6 vertebrae, and prophylactic foraminotomy for the prevention of C5
4
nerve palsy.2 In addition, laminoplasty plates have become increasingly popular.17 In a recent
5
systematic review, over 50% of laminoplasty studies investigated the use of miniplates and
6
screws.2 In a similar review published 10 years earlier, only 6% of articles reported clinical
7
outcomes of miniplates.18 The advantages of laminoplasty plates include immediate
8
postoperative stability allowing for early range of motion, decreased need for postoperative
9
bracing, lower risk of premature laminoplasty closure, and greater stabilization of excessively
10
thinned hinges.7 Maeda et al demonstrated that early range of motion and limited soft collar use
11
may prevent cervical stiffness and the development of postoperative kyphosis.19 Other studies
12
suggest that the incidence of axial pain is lower in patients treated with miniplates compared to
13
less rigid fixation techniques20, 21, although this is controversial.22, 23 Nevertheless, plate breakage
14
and migration may represent an under-reported and under-recognized complication in the
15
laminoplasty literature. Although rare, the consequences of iatrogenic spinal cord lesions can be
16
devastating.6 The purpose of this case report was to describe the diagnosis and treatment of
17
multilevel hinge non-union, plate breakage, and intra-dural plate fragment migration after
18
cervical laminoplasty. We also recommend that the hinge width be optimized using a burr no
19
larger than 2 mm to avoid intra-operative hinge fracture and postoperative hinge non-union.
20 21
Previous authors have identified three main categories of laminoplasty failures: “technique
22
related” (with new, early-onset postoperative symptoms), “inadequate treatment” (characterized
23
by residual preoperative symptoms), and “disease progression” (in which new, late-onset
6 1
postoperative symptoms develop).8,
24
2
recommendations for their prevention and treatment are summarized in Table 1. The most
3
common reason for revision surgery is recurrence or worsening of symptoms due to disease
4
progression either within or adjacent to the laminoplasty levels.8 Although laminoplasty is a
5
motion-preserving procedure, previous authors have reported decreased range of motion and
6
altered spinal biomechanics which may contribute to adjacent segment degeneration.25, 26 In a
7
retrospective review of 237 patients who underwent laminoplasty for CSM, Shigematsu et al
8
reported five cases of revision surgery due to laminoplasty closure (n=2), adjacent segment
9
degeneration (n=2), and foraminal stenosis (n=1).24 Revision surgery included laminectomy,
10
repeat laminoplasty, or foraminotomy based on the site(s) of compression, sagittal alignment of
11
the cervical spine, general condition of the patient, and surgeon preference. In a retrospective
12
study of 130 patients with CSM and OPLL, 25% of revisions were performed due to
13
laminoplasty closure and re-stenosis of treated levels at 3 years postoperatively.8 The
14
laminoplasty door was held open by suture anchors in each case and there were no closures
15
observed in patients treated with plate fixation. The authors report that each laminoplasty closure
16
was treated successfully with laminectomy and fusion, while patients with inadequate symptom
17
relief and disease progression were primarily treated with anterior cervical discectomy and
18
fusion (ACDF).
Late complications associated with laminoplasty and
19 20
An anterior approach may be considered in laminoplasty patients requiring revision surgery due
21
to loss of lordotic alignment and anterior compressive pathology such as progression of OPLL
22
and/or disc herniation.27 Although laminoplasty achieves significant spinal canal expansion
23
posteriorly,28 anterior compression may still be present postoperatively due to technique-related
7 1
factors such as inadequate opening angle.8, 27, 29 Furthermore, OPLL progression occurs in most
2
patients following laminoplasty and averages 9 mm in the longitudinal axis and 1.3 mm in
3
anterior-posterior axis at 10 years of follow up.30 Previous studies also suggest that ACDF may
4
be preferable to laminoplasty in cases where OPLL occupies more than 60% of the spinal canal
5
or is thicker than 7 mm preoperatively.31,
6
cases due to persistent anterior compression and cervical instability, revision ACDF with
7
autogenous fibular strut graft achieved significant improvements in clinical outcomes including
8
reductions in radicular and axial neck pain.27 Circumferential fusion has also been used in
9
revision laminoplasty patients at high risk for non-union and instrumentation failure due to spinal
10
deformity and poor neck control.8 Based on prior studies, we recommend anterior approaches for
11
laminoplasty revision surgery in cases of large anterior cord compression, cervical instability and
12
loss of lordotic alignment, and OPLL involving more than 60% of the spinal canal.
32
In a retrospective analysis of failed laminoplasty
13 14
Additional postoperative complications associated with cervical laminoplasty include screw
15
back-out, hinge non-union, and delayed (or postoperative) hinge fracture. Liu et al and Rhee et al
16
investigated the incidence and clinical significance of screw back-out following plate
17
laminoplasty and found no associated cases of plate failure, laminoplasty closure, or clinical
18
symptoms.7, 16 However, follow up in each study was limited to 1-2 years and it is possible that
19
longer follow-up is needed to detect plate failures. Screw back-out appears to not cause
20
significant clinical problems in the early postoperative period but may eventually lead to
21
laminoplasty plate failure as seen in our case report. While delayed hinge fracture may contribute
22
to postoperative axial neck pain or cause significant spinal cord compression and neurologic
23
deficits, hinge fractures heal within 1-2 years in most cases.7, 23, 33 As a result, some authors have
8 1
recommended careful follow up without the need for additional surgical intervention such as
2
conversion to laminectomy and fusion.34
3 4
Although few biomechanical studies on laminoplasty plate fixation strength exist, hinge non-
5
union likely contributed to the plate breakages observed in our patient. “Floppy” hinges may
6
decrease the stability of the laminae, thus producing increased strain on the laminoplasty plates
7
and eventual breakage. While the mechanisms of plate failure have not been investigated, a
8
biomechanical study by Tadepalli et al demonstrated that cervical cadaveric vertebrae treated
9
with open door laminoplasty plates fail at the hinge under both direct compressive and
10
parasagittal loading.35 Finite element analysis revealed that the peak stresses in the laminoplasty
11
plates were far below the yield strength of titanium alloy, and therefore neither screw pull-out
12
nor plate failure was observed during cadaveric load to failure testing. While the loading
13
conditions tested in this study reflect the stability of the laminoplasty to resist laminar closure,
14
cranio-caudal compression also results in hinge failure and is more relevant to patients treated
15
with muscle-sparing techniques (due to intact extensor function).36 Furthermore, laminoplasty
16
plates are notably smaller than most plates used in the spine and extremities. Since laminoplasty
17
is a motion-preserving procedure, these plates are subjected to repetitive stress with each cycle of
18
motion. In our patient’s case, multiple hinge non-unions were observed at the C5-C7 vertebra
19
and plate breakage was seen at C4, C6, and C7. While the C4 hinge was deemed stable
20
intraoperatively, hinge non-union likely increased the strain on the C6 and C7 plates and
21
contributed to their failure.
22
9 1
In addition, over-resection of the ventral cortex may have contributed to hinge non-union and
2
subsequent plate breakage. Previous studies have identified risk factors for hinge fracture such as
3
medially placed hinge gutters and involvement of the C3-C5 surgical levels (due to relatively
4
thinner laminae medially and compared to the C6 and C7 vertebrae).23, 37 Medially placed gutters
5
also require increased opening angles to achieve the same level of laminar elevation. Hinge
6
fracture may occur during laminar elevation if too little bone has been removed.38 Alternatively,
7
removal of too much ventral cortex may result in an unstable “floppy” hinge and delayed
8
fracture, which may result in spinal cord compression due to intrusion of the fractured lamina
9
into the spinal canal.14, 15 The pliability and stiffness of the greenstick deformation are assessed
10
intraoperatively to prevent either mechanism of failure. Despite these surgical precautions,
11
trough creation can be technically difficult and reported rates of non-union range from 2-16%.7,
12
13, 33, 39
13
laminoplasty troughs. Some authors have recommended a 2-mm acorn-shaped burr for trough
14
creation to limit hinge width.40 Increased bone gaps may also adversely affect bony healing,
15
especially if a delayed fracture occurs.33 We recommend a 2-mm burr for more consistent
16
preservation of the ventral cortex and creation of smaller bone gaps, as demonstrated in Figure 5.
17
Furthermore, a color change in the cortex may be appreciated while creating hinges.41 As the
18
ventral cortex thins, yellow and blue areas corresponding to the ligamentum flavum and dural
19
veins may be visualized through the bone. In the event of intraoperative hinge instability, salvage
20
plates can be used to fix the lamina to the lateral mass.41 Some surgeons routinely bone graft the
21
hinge side with local autograft.42
22
Of note, a high-speed burr with a 3-mm M8 diamond tip was used to create our patient’s
10 1
One limitation of this case report is that we lacked interval imaging between the patient’s initial
2
laminoplasty procedure and his revision surgery 7 years later. Therefore, the timeline of hinge
3
non-union and plate breakage is largely unknown. Previous studies suggest that hinge fractures
4
most often occur in the early postoperative period (within 4 months of surgery), although the
5
majority remain stable for up to 2 years.23 Furthermore, Park et al reported that patients with
6
three or more hinge fractures had significantly worse pain and disability scores compared with
7
two or less.23 Other studies suggest no difference in clinical outcomes between patients with and
8
without hinge non-union.43
9 10
Conclusion
11 12
We report a rare case of multiple laminoplasty hinge non-union, plate breakage, and intra-dural
13
plate fragment migration. Care must be taken to avoid over-resection of the ventral cortex during
14
laminoplasty. We also recommend a 2-mm burr to limit hinge width and reduce the dorsal bone
15
gap. Hinge non-union may result in laminar instability and produce increased strain on the
16
laminoplasty plate. Intra-dural fragment migration and symptomatic spinal cord compression are
17
possible complications of plate failure. In this case, urgent plate removal and laminectomy was
18
successful and the patient’s symptoms resolved completely.
19 20 21 22 23 24 25 26 27 28
11 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Table 1. Literature review of late postoperative complications associated with cervical laminoplasty Complication Progression of disease (OPLL, CSM)8, 24, 26
Laminoplasty closure3, 10, 24
Delayed hinge fracture14, 15
Laminoplasty screw back-out7, 16
Hydroxyapatite spacer displacement and dural laceration5, 6, 33 Postoperative kyphosis18
Recommendations for prevention and treatment • Revision surgery depending on the site(s) of compression, sagittal alignment of the cervical spine, general condition of the patient, and surgeon preference.24, 27 • Anterior approaches for cases of large anterior cord compression, loss of lordotic alignment, and OPLL involving more than 60% of the spinal canal.8, 27, 31, 32 • Use of laminoplasty spacers or plates in patients at high risk of closure (e.g., decreased lordosis, OPLL).7, 44 • Treatment often includes repeat laminoplasty or revision laminectomy.3, 24 • Use of a 2- or 3-mm burr to avoid excessive removal of ventral cortex.40, 45 • Avoidance of medially placed hinge gutters on the opening side.23, 46 • Frequent checks of hinge stability intraoperatively.23 • Careful follow up with postoperative CT scans.13 • Use of two laminar screws.7 • Retightening of the first screw after placement of the second screw.16 • Use of longer (7 mm) screws to increase bone purchase.16 • Judicial dissection at the proximal and distal ends of the laminoplasty construct.16 • Placement of spacers at the base of the spinous process.47 • Spinous process splitting using a thread-wire saw.5 • Use of mini-plate fixation.48, 49 • Restriction of the laminoplasty from C3-C6.50 • Use of muscle/posterior element-sparing techniques.2
12
Postoperative loss of ROM
25, 26
• • •
Early range of motion and limited soft collar use.19, 51 Use of muscle/posterior element-sparing techniques.2 Early range of motion and limited soft collar use.19, 51
1 2 3 4 5
Figures
6 7
Figure 1. Postoperative sagittal radiograph of the cervical spine following open-door
8
laminoplasty from C3-C7. Four 10-mm and one 12-mm Centerpiece Medtronic Sofamor Danek
9
plates were used. There were no complications and the patient recovered well from surgery.
10 11
Figure 2. Axial (A) and sagittal (B) T2-weighted MRI views of the cervical spine demonstrating
12
intra-dural migration of a fragment of the C7 plate immediately adjacent to the left spinal cord.
13
(C) Axial CT of the cervical spine showing intra-dural migration of a fragment of the C7 plate.
14
(D) Intraoperative photos of the C7 plate fragment in the dorsal dura at the medial edge of the C7
15
lateral mass (black arrow – plate fragment, white arrow – dural defect with spinal cord visible).
16 17
Figure 3. Axial CT views demonstrating hinge union at C4 (A) and hinge non-union at C7 (B).
18
Hinge healing is complete when both the ventral and dorsal cortices are bridged with bone 7, as
19
seen in (A).
20 21
Figure 4. Anteroposterior (A) and lateral (B) radiographs of the cervical spine following C5-C7
22
laminectomy and fusion.
13 1 2
Figure 5. Pictures demonstrating the difference between the use of a 4-mm burr (left column) vs.
3
2-mm burr for creation of the trough and opening hinge in a C5 cervical spine bone model. A 1-
4
cm spacer was inserted into the opening wedge.
5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
References 1. 2. 3.
4. 5.
6.
7.
8.
9.
10.
11.
Hirabayashi K, Watanabe K, Wakano K, Suzuki N, Satomi K, Ishii Y. Expansive open-door laminoplasty for cervical spinal stenotic myelopathy. Spine. Oct 1983;8(7):693-699. Duetzmann S, Cole T, Ratliff JK. Cervical laminoplasty developments and trends, 20032013: a systematic review. Journal of neurosurgery. Spine. Jul 2015;23(1):24-34. Satomi K, Ogawa J, Ishii Y, Hirabayashi K. Short-term complications and long-term results of expansive open-door laminoplasty for cervical stenotic myelopathy. The spine journal : official journal of the North American Spine Society. Jan-Feb 2001;1(1):26-30. Morio M, Kota W, Takashi T, et al. Risk factors for closure of lamina after open-door laminoplasty. Journal of Neurosurgery: Spine SPI. 2008;9(6):530-537. Ono A, Yokoyama T, Numasawa T, Wada K, Toh S. Dural damage due to a loosened hydroxyapatite intraspinous spacer after spinous process–splitting laminoplasty. 2007;7(2):230. Kanemura A, Doita M, Iguchi T, Kasahara K, Kurosaka M, Sumi M. Delayed dural laceration by hydroxyapatite spacer causing tetraparesis following double-door laminoplasty. 2008;8(2):121. Rhee JM, Register B, Hamasaki T, Franklin B. Plate-only open door laminoplasty maintains stable spinal canal expansion with high rates of hinge union and no plate failures. Spine. Jan 1 2011;36(1):9-14. Liu G, Buchowski JM, Bunmaprasert T, Yeom JS, Shen H, Riew KD. Revision surgery following cervical laminoplasty: etiology and treatment strategies. Spine. Dec 1 2009;34(25):2760-2768. Veeravagu A, Azad TD, Zhang M, et al. Outcomes of cervical laminoplasty—Populationlevel analysis of a national longitudinal database. Journal of Clinical Neuroscience. 2018/02/01/ 2018;48:66-70. Tamai K, Suzuki A, Terai H, Toyoda H, Hoshino M, Nakamura H. Laminar closure after expansive open-door laminoplasty: fixation methods and cervical alignments impact on the laminar closure and surgical outcomes. The Spine Journal. 2016/09/01/ 2016;16(9):1062-1069. Suk KS, Kim KT, Lee JH, Lee SH, Lim YJ, Kim JS. Sagittal alignment of the cervical spine after the laminoplasty. Spine. Nov 1 2007;32(23):E656-660.
14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44
12.
13.
14.
15. 16. 17.
18. 19.
20.
21.
22. 23.
24.
25. 26.
27.
Lee JH, Chough CK. Risk Factors for Hinge Fracture Associated with Surgery Following Cervical Open-Door Laminoplasty. Korean journal of neurotrauma. Oct 2018;14(2):118122. Lee D-H, Kim H, Lee CS, Hwang C-J, Cho J-H, Cho SK. Clinical and radiographic outcomes following hinge fracture during open-door cervical laminoplasty. Journal of Clinical Neuroscience. 2017/09/01/ 2017;43:72-76. Yonenobu K, Oda T. Posterior approach to the degenerative cervical spine. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society. Oct 2003;12 Suppl 2:S195-201. Hosono N, Sakaura H, Mukai Y, Ishii T, Yoshikawa H. En bloc laminoplasty without dissection of paraspinal muscles. Journal of neurosurgery. Spine. Jul 2005;3(1):29-33. Liu G, Buchowski JM, Riew KD. Screw Back-Out Following "Open-Door" Cervical Laminoplasty: A Review of 165 Plates. Asian spine journal. 2015;9(6):849-854. Park AE, Heller JG. Cervical laminoplasty: use of a novel titanium plate to maintain canal expansion--surgical technique. Journal of spinal disorders & techniques. Aug 2004;17(4):265-271. Ratliff JK, Cooper PR. Cervical laminoplasty: a critical review. Journal of neurosurgery. Apr 2003;98(3 Suppl):230-238. Maeda T, Arizono T, Saito T, Iwamoto Y. Cervical alignment, range of motion, and instability after cervical laminoplasty. Clinical Orthopaedics and Related Research. 2002(401):132-138. Dimar JR, 2nd, Bratcher KR, Brock DC, Glassman SD, Campbell MJ, Carreon LY. Instrumented open-door laminoplasty as treatment for cervical myelopathy in 104 patients. American journal of orthopedics (Belle Mead, N.J.). Jul 2009;38(7):E123-128. Chen H, Liu H, Zou L, et al. Effect of Mini-plate Fixation on Hinge Fracture and Bony Fusion in Unilateral Open-door Cervical Expansive Laminoplasty. Clinical spine surgery. Jul 2016;29(6):E288-295. Jiang L, Chen W, Chen Q, Xu K, Wu Q, Li F. Clinical application of a new plate fixation system in open-door laminoplasty. Orthopedics. 2012;35(2):e225-e231. Park YK, Lee DY, Hur JW, Moon HJ. Delayed hinge fracture after plate-augmented, cervical open-door laminoplasty and its clinical significance. The spine journal : official journal of the North American Spine Society. Jul 1 2014;14(7):1205-1213. Shigematsu H, Koizumi M, Matsumori H, et al. Revision surgery after cervical laminoplasty: report of five cases and literature review. The spine journal : official journal of the North American Spine Society. Jun 1 2015;15(6):e7-13. Seichi A, Takeshita K, Ohishi I, et al. Long-term results of double-door laminoplasty for cervical stenotic myelopathy. Spine. Mar 1 2001;26(5):479-487. Chiba K, Ogawa Y, Ishii K, et al. Long-term results of expansive open-door laminoplasty for cervical myelopathy--average 14-year follow-up study. Spine. Dec 15 2006;31(26):2998-3005. Komura S, Miyamoto K, Hosoe H, et al. Anterior cervical multilevel decompression and fusion using fibular strut as revision surgery for failed cervical laminoplasty. Archives of Orthopaedic and Trauma Surgery. September 01 2011;131(9):1177-1185.
15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43
28.
29. 30.
31.
32.
33.
34.
35.
36.
37.
38. 39. 40. 41. 42.
Takahashi Y, Narusawa K, Shimizu K, Hijioka A, Nakamura T. Enlargement of cervical spinal cord correlates with improvement of motor function in upper extremities after laminoplasty for cervical myelopathy. Journal of spinal disorders & techniques. May 2006;19(3):194-198. Yuan W, Zhu Y. Posterior Revision Surgery for Cervical Open-Door Laminoplasty Because of Poor Expansion of the Spinal Canal. World Neurosurg. Oct 2019;130:e90-e97. Kawaguchi Y, Kanamori M, Ishihara H, et al. Progression of ossification of the posterior longitudinal ligament following en bloc cervical laminoplasty. The Journal of bone and joint surgery. American volume. Dec 2001;83(12):1798-1802. Iwasaki M, Okuda S, Miyauchi A, et al. Surgical strategy for cervical myelopathy due to ossification of the posterior longitudinal ligament: Part 2: Advantages of anterior decompression and fusion over laminoplasty. Spine. Mar 15 2007;32(6):654-660. Yamazaki A, Homma T, Uchiyama S, Katsumi Y, Okumura H. Morphologic limitations of posterior decompression by midsagittal splitting method for myelopathy caused by ossification of the posterior longitudinal ligament in the cervical spine. Spine. Jan 1 1999;24(1):32-34. Tanaka N, Nakanishi K, Fujimoto Y, et al. Expansive laminoplasty for cervical myelopathy with interconnected porous calcium hydroxyapatite ceramic spacers: comparison with autogenous bone spacers. Journal of spinal disorders & techniques. Dec 2008;21(8):547552. Lee DH, Kim H, Lee CS, Hwang CJ, Cho JH, Cho SK. Clinical and radiographic outcomes following hinge fracture during open-door cervical laminoplasty. Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia. Sep 2017;43:72-76. Tadepalli SC, Gandhi AA, Fredericks DC, Grosland NM, Smucker J. Cervical laminoplasty construct stability: an experimental and finite element investigation. The Iowa orthopaedic journal. 2011;31:207-214. Ohara Y, Hara T, Orías AAE, Tani S, Inoue N, Mizuno J. In vitro biomechanical evaluation of a monocoque plate-spacer construct for cervical open-door laminoplasty. PloS one. 2018;13(10):e0204147-e0204147. Hur JW, Park YK, Kim BJ, Moon HJ, Kim JH. Risk Factors for Delayed Hinge Fracture after Plate-Augmented Cervical Open-Door Laminoplasty. Journal of Korean Neurosurgical Society. Jul 2016;59(4):368-373. Thakur NA, Heller JG. Cervical laminoplasty: Review of complications and strategies to avoid them. Seminars in Spine Surgery. 2013/09/01/ 2013;25(3):209-213. Lee S, Chung CK, Kim CH. Risk factor analysis of hinge fusion failure after plate-only open-door laminoplasty. Global spine journal. Feb 2015;5(1):9-16. Lehman RA, Jr., Taylor BA, Rhee JM, Riew KD. Cervical laminaplasty. The Journal of the American Academy of Orthopaedic Surgeons. Jan 2008;16(1):47-56. Leckie SK, Kercher JS, Yoon ST. Cervical Laminoplasty. In: Rhee JM, ed. Operative Techniques in Spine Surgery. Philadelphia: Wolters Kluwer; 2016:27-35. Onuma H, Hirai T, Yoshii T, et al. Clinical and radiologic outcomes of bone grafted and non-bone grafted double-door laminoplasty, the modified Kirita-Miyazaki method, for
16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
43.
44.
45. 46.
47.
48.
49.
50.
51.
treatment of cervical spondylotic myelopathy: Five-year follow-up. Journal of Orthopaedic Science. 2018/11/01/ 2018;23(6):923-928. Cho SH, Lee JH, Chough CK, et al. Hinge Fracture during Cervical Open-door Laminoplasty: Does it Affect Clinical and Radiographic Outcomes? Korean Journal of Spine. Jun 2014;11(2):45-51. Matsumoto M, Watanabe K, Hosogane N, et al. Impact of lamina closure on long-term outcomes of open-door laminoplasty in patients with cervical myelopathy: minimum 5year follow-up study. Spine. Jul 1 2012;37(15):1288-1291. Kawaguchi Y, Matsui H, Ishihara H, Gejo R, Yoshino O. Axial symptoms after en bloc cervical laminoplasty. Journal of spinal disorders. Oct 1999;12(5):392-395. Satomi K, Nishu Y, Kohno T, Hirabayashi K. Long-term follow-up studies of open-door expansive laminoplasty for cervical stenotic myelopathy. Spine. Mar 1 1994;19(5):507510. Kaito T, Hosono N, Makino T, Kaneko N, Namekata M, Fuji T. Postoperative displacement of hydroxyapatite spacers implanted during double-door laminoplasty. Journal of neurosurgery. Spine. Jun 2009;10(6):551-556. Goto T, Ohata K, Takami T, et al. Hydroxyapatite laminar spacers and titanium miniplates in cervical laminoplasty. Journal of neurosurgery. Oct 2002;97(3 Suppl):323329. Tanaka S, Tashiro T, Gomi A, Ujiie H. Cervical unilateral open-door laminoplasty with titanium miniplates through newly designed hydroxyapatite spacers. Neurologia medico-chirurgica. 2011;51(9):673-677. Sakaura H, Hosono N, Mukai Y, Iwasaki M, Yoshikawa H. Medium-term outcomes of C36 laminoplasty for cervical myelopathy: a prospective study with a minimum 5-year follow-up. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society. Jun 2011;20(6):928-933. Kimura A, Seichi A, Inoue H, Hoshino Y. Long-term results of double-door laminoplasty using hydroxyapatite spacers in patients with compressive cervical myelopathy. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society. 2011;20(9):1560-1566.
cm – Centimeters CSF - cerebrospinal fluid CSM - cervical spondylotic myelopathy CT - computed tomography MRI - Magnetic Resonance Imaging mm - Millimeters OPLL - ossification of the posterior longitudinal ligament