Surgical Approaches for the Treatment of Multilevel Cervical Ossification of the Posterior Longitudinal Ligament: Results of a Decision Analysis

Accepted Manuscript Surgical Approaches for the Treatment of Multilevel Cervical Ossification of the Posterior Longitudinal Ligament: Results of a Decision Analysis Nikhil R. Nayak, MD, Matthew Piazza, MD, Andrew Milby, MD, Jayesh P. Thawani, MD, Lachlan J. Smith, PhD, Sherman C. Stein, MD, Neil R. Malhotra, MD PII:

S1878-8750(18)30094-9

DOI:

10.1016/j.wneu.2018.01.051

Reference:

WNEU 7249

To appear in:

World Neurosurgery

Received Date: 25 May 2017 Revised Date:

5 January 2018

Accepted Date: 11 January 2018

Please cite this article as: Nayak NR, Piazza M, Milby A, Thawani JP, Smith LJ, Stein SC, Malhotra NR, Surgical Approaches for the Treatment of Multilevel Cervical Ossification of the Posterior Longitudinal Ligament: Results of a Decision Analysis, World Neurosurgery (2018), doi: 10.1016/j.wneu.2018.01.051. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. 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.

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Surgical Approaches for the Treatment of Multilevel Cervical Ossification of the Posterior Longitudinal Ligament: Results of a Decision Analysis Nikhil R. Nayak, MD1; Matthew Piazza, MD1; Andrew Milby, MD2; Jayesh P. Thawani, MD1; Lachlan J. Smith, PhD1; Sherman C. Stein, MD1; Neil R. Malhotra, MD1 1

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Hospital of the University of Pennsylvania Department of Neurosurgery 3400 Spruce Street, 3 Silverstein Pavilion Philadelphia, PA 19104

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Hospital of the University of Pennsylvania Department of Orthopedic Surgery 3400 Spruce Street, 2 Silverstein Pavilion Philadelphia, PA 19104

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Neil R. Malhotra, MD (215) 615-5454 (Phone) (215) 349-5534 (Fax) [email protected] Hospital of the University of Pennsylvania Department of Neurosurgery 3400 Spruce Street, 3 Silverstein Pavilion Philadelphia, PA 19104

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Corresponding Author:

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Abbreviations: antero-posterior (AP); cervical spondylotic myelopathy (CSM); computed tomography (CT); health-related quality of life (HRQoL); Japanese Orthopedic Association myelopathy scale (JOA); magnetic resonance imaging (MRI); space-occupying ratio (SOR); Ossification of the posterior longitudinal ligament (OPLL); quality-adjusted life years (QALYs) Keywords: ossification of posterior longitudinal ligament; cervical myelopathy; quality of life outcomes

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Number of Figures/Tables: 0/5

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Abstract

Background: Ossification of the posterior longitudinal ligament (OPLL) often leads to cervical

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myelopathy. While multiple procedures have been shown to be effective in the treatment of OPLL, outcomes are less predictable than in degenerative cervical myelopathy and surgery is associated with high rates of complications and re-operation which affect quality of life. In this study, we perform a

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decision analysis utilizing post-operative complication data and health-related quality of life (HRQoL) utility scores to assess the average expected health utility and 5-year quality-adjusted life years (QALYs)

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associated with the most common surgical approaches for multilevel cervical OPLL.

Methods: We searched Medline, EMBASE and the Cochrane Library for relevant articles published between 1990 and October 2017. Meta-analytically pooled complication data and HRQoL utility scores

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associated with each complication were evaluated in a long term model.

Results: The overall incidence of peri-operative complications ranged from 6.2% for laminectomy alone

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to 11.0% for anterior decompression and fusion. Revision surgery for hardware/fusion failure or progression was highest in for laminectomy alone (3.0%) and lowest for laminectomy and fusion (1.6%).

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Laminoplasty resulted in the highest 5-year QALYs gained, compared with laminectomy and anterior approaches (p < 0.001). There was no significant difference in QALY gained between laminectomy-fusion and laminoplasty.

Conclusion: The results suggest that due to higher rates of complications associated with anterior cervical approaches, laminoplasty may result in improved long-term outcomes from an HRQoL standpoint. These findings may guide surgeons in cases where either procedure is a reasonable option.

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Introduction

Ossification of the posterior longitudinal ligament (OPLL) is characterized by the progressive

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hypertrophy and mineralization of the posterior longitudinal ligament, eventually resulting in the

formation of ossification centers with active bone marrow and frank bone formation.1,2 It typically presents as myelopathy in middle-aged or elderly individuals. It is most common among eastern Asian

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communities, with prevalence rates are as high as 4.3% in the Japanese population over age 30, while rates among non-Asian populations are considerably lower and estimated at 0.1-1.7%.3 The

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pathogenesis is believed to be multifactorial, and a growing body of research suggests that there is a strong genetic component, with association of several genes involved in processes such as collagen formation, bone metabolism, and endochondral ossification.4–8

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Symptomatic OPLL requiring surgical intervention represents a unique subset of cervical myelopathy patients due to the morphologic complexities of the OPLL mass, challenges associated with directly excising OPLL, and patient-related factors. Morphologically, there are four distinct radiographic subtypes

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of OPLL which can influence surgical decision making: 1) continuous – single OPLL mass spanning two or more vertebrae; 2) segmental (most common) – fragmented lesions posterior to the vertebral bodies

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that do not fully cross disc spaces; 3) mixed type – combination of continuous and segmental; 4) other – ossification posterior to the disc.9 Surgical approaches include anterior decompression and fusion, as well as various posterior decompression procedures with or without fusion. Anterior approaches generally involve varying degrees of corpectomy to access to the OPLL mass and subsequent strut graft or cage placement for vertebral column reconstruction. Posterior approaches (laminectomy, laminectomy with instrumented fusion, and laminoplasty) provide indirect decompression, as the OPLL mass is left untouched. Each of these four major surgical approaches has a unique set of advantages and

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disadvantages, and the decision to employ one approach over another is often dictated by prior surgeon experience and patient-specific characteristics (e.g. kyphotic deformity requiring an anterior procedure).

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Numerous studies have shown that both anterior and posterior approaches are effective in the

treatment of OPLL-related cervical myelopathy, although the precise choice of procedure has long been a matter of debate.10 While the heterogeneity associated with OPLL-related myelopathy makes cases of

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true clinical equipoise uncertain, there are often situations where multiple surgical approaches are feasible for a given lesion. Prior studies comparing two or more procedures head-to-head have generally

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made comparisons based on operative metrics and myelopathy scores, such as the Japanese Orthopedic Association myelopathy scale (JOA) or Nurick grade. However, surgery for OPLL is associated with high rates of complications; if complication rates vary between surgical approaches, health-related quality of

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life (HRQoL) should also vary and may not be reflected in neurologic outcome measures.11

In this study, we seek to compare the four major surgical approaches to OPLL-related cervical myelopathy (posterior laminectomy, posterior laminectomy and fusion, laminoplasty, and anterior

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decompression/fusion) by analyzing post-operative complication data from the published literature, in conjunction with utility scores, to determine the average expected utility and 5-year quality-adjusted life

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years (QALYs) gained from each procedure.

Materials and Methods

We searched Medline, EMBASE and the Cochrane online databases for articles containing the key words “ossification” (or “ossified”), “posterior,” “longitudinal” AND “ligament” in the text. We limited our search to English-language articles published between 1990 and October 2017. We also supplemented

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the search by using the “Related Articles” feature of PubMed and by manually searching the bibliographies of selected articles. We included series with 10 or more operated cases. Articles were divided into those in which the operative approaches were one or more of the following: 1) anterior

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decompression with or without fusion (“anterior approach”); 2) laminectomy without fusion; 3)

laminectomy with instrumented posterior fusion (“laminectomy-fusion”); 4) laminoplasty. At least two authors reviewed each article to obtain pooled data for the evidence tables, from which we calculated

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the probabilities of the various treatment outcomes.

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We created a decision-analytic model using standard procedures to compare the four surgical approaches.12 Our primary analysis involved calculating likely outcomes following different approaches for symptomatic multilevel OPLL. For each operative approach under consideration, we calculated the incidence of peri-operative complications and long-term re-operations. Separate sub-trees were created

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to calculate the expected probabilities and utility scores of patients suffering non-fatal complications. The following complications were assessed: spinal cord injury, nerve root injury, CSF leak either requiring re-operation or management resulting in either invasive procedures and/or extended length of

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stay (i.e. lumbar drain placement, bed rest, pseudomeningocoele tap), post-operative hematoma, and re-operation for graft or hardware failure, pseudoarthrosis, persistent symptoms, or disease

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progression. For the purposes of calculating complication rates, articles were included only if the individual complications were noted. If an article mentioned that no cases of a particular complication had occurred, the incidence was noted as zero for that series. Not every article reported all categories of data needed for analysis; missing data were excluded from analyses of that data category. Utility scores associated with individual complications were are listed in Table 1. Initial treatment expected utility was calculated from the rate of complications and associated utility for each treatment modality. Long term outcomes depended on the incidence of late treatment failures defined as the need for repeat or

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additional surgery for further stabilization and/or decompression of neural elements for instances of hardware or graft failure, persistent symptoms, or progression of disease. Reoperation probabilities were determined by meta-regression, in which reoperation rate is plotted against follow-up time. There

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was a significant increase in reoperation rate only in the case of anterior decompression and fusion. Accordingly, the 5-year recurrence rate was calculated by meta-regression. The rates for the other approaches did not appear to increase over time and were calculated by meta-analysis. We estimated

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the utility of a second operation to be 91.5% of that had the operation been done the first time.13

QALYs were calculated from the summation of expected utility for each year following surgery adjusted

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for expected complications. Observational data was pooled meta-analytically using an inverse varianceweighted, random effects model.14 Data pooling followed the guidelines of the meta-analysis of observational studies in epidemiology group.15

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Analyses of the model employed TreeAge Pro 2012 (Tree Age Software, Inc., Williamstown, MA). Sensitivity analysis was done using a two-dimensional Monte Carlo simulation (expected value for 100 simulated trials, each made up of 100 microsimulations).16 Outcome comparisons among the four

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approaches employed analysis of variance (ANOVA) with Bonferroni correction for multiple comparisons. Meta-analytic pooling used the metan function of Stata (v. 12, StataCorp, College Station,

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TX). Differences for which the probability was < 0.05 were considered significant.

Results

Our initial search yielded 1,068 abstracts, of which 795 were discarded as unsuitable due to language, topic, or irrelevant diagnoses. This left 273 articles, which were downloaded and reviewed in detail; of these, only 52 articles met inclusion criteria for the study, totaling 3,963 cases, compiled in Table 2. We

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omitted articles that reported multiple procedures but did not separate outcomes by surgical approach. Since none of the series involved randomized trials, including the fourteen studies comparing multiple

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approaches,17–30 they can all be considered Level III evidence.31

There was no significant difference in mean age or sex distribution among the groups (Table 3). There were fewer operated spinal levels in the anterior cohort (p<0.001 for each pairwise comparison), but

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there were otherwise no significant differences in the number of operated levels between the three posterior procedures. The types and probabilities of perioperative and delayed complications for each

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approach were calculated using meta-analytic pooling and are summarized in Table 4. The overall incidence of complications ranged from 6.2% for laminectomy alone to 11.0% for anterior approaches. Re-operations for failure of the construct, pseudoarthrosis, disease progression or persistent symptoms totaled 2.4% for anterior approaches, 3.0% for laminectomy alone, 1.6% for laminectomy-fusion and

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2.5% for laminoplasty.

The expected utilities for all cases (with and without complications), expressed in cumulative 5-year

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QALYs for each surgical approach are summarized in Table 5. The best results were seen after laminoplasty (4.909 QALYs), the worst with laminectomy alone (4.833 QALYs). Of note, a perfect surgical

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outcome at 5 years would result in 5 QALYs. Differences among groups in pairwise ANOVA comparisons showed that laminoplasty was not significantly better than laminectomy-fusion (p = .311) but was superior to anterior surgery and laminectomy alone (p < 0.001)

Discussion

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Symptomatic OPLL often leads to cervical myelopathy requiring surgical intervention. Multiple procedures have been shown to be effective in the treatment of OPLL-related cervical myelopathy, although the unique pathophysiology of the disease makes surgical management more difficult, and

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outcomes less predictable, than in degenerative cervical spondylotic myelopathy (CSM). Prior efforts to compare anterior and posterior procedures have been primarily based on neurologic outcome scales such as the JOA or Nurick grading systems, although given the high rates of surgical complications in this

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patient population, global HRQoL cannot be ignored. The results of our study suggest that at 5 years post-operatively, laminoplasty may result in the greatest QALYs gained, with 5-year QALYs gained

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significantly less following anterior procedures and laminectomy alone.

Anterior surgery for OPLL is an intuitive approach as it affords direct access to the offending pathology. Because compression from the most common morphologies of OPLL is not directly accessible via

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discectomy alone, unlike many cases of degenerative disc disease, varying degrees of multi-level corpectomy are usually required for adequate anterior decompression. The OPLL mass may be directly excised, although high rates of dural tears have led some surgeons to employ the “anterior floating

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method,” in which the OPLL mass is shaved to a thin shell, disconnected from the vertebral column and left in place, thereby decompressing the spinal cord without the advertent risks of dissecting the bone

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from dura.32,33 Oblique corpectomy, another anterior strategy, entails oblique cuts through the vertebral body/disc that allow complete decompression of the spinal cord while removing at most 50% of the anterior column and preserving much of the anterior longitudinal ligament. The principle advantage of this strategy is that it is less destabilizing then full corpectomy and hence does not require graft placement or instrumentation, although there is a theoretical greater risk for Horner’s syndrome and vertebral artery injury secondary to the lateral starting point for the corpectomy.34,35 Factors that influence adopting an anterior approach include kyphotic angulation, younger age (as continued growth

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of an untouched OPLL mass may require late re-operation), and OPLL morphology that may preclude adequate decompression from a posterior approach.

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Posterior approaches for OPLL-related myelopathy are familiar to most neurosurgeons because, from a technical standpoint, they are essentially the same as those utilized for degenerative CSM. Posterior approaches provide indirect decompression, as the offending pathology remains untouched and the

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spinal cord is allowed to drift posteriorly. Primary concerns associated with posterior approaches

include continued growth of the OPLL mass and iatrogenic instability. Most posterior cases are reserved

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for patients without kyphotic deformities. Loss of normal cervical lordosis or the need for aggressive nerve root decompression may prompt surgeons to perform concomitant instrumented fusion or laminoplasty rather than laminectomy alone to avoid possible post-operative deformity.36 The laminectomy-fusion cohort in our study had the highest rate of nerve root injury (e.g. C5 palsy) compared to all other procedures. This finding is consistent with prior reports of this phenomenon

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following posterior cervical decompression for non-OPLL diagnoses.37

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Cervical laminoplasty is the most recently developed of the four procedures, having been introduced in Japan during the late 1970s.38 Laminoplasty involves expanding the volume of the spinal canal by

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dorsally transposing the posterior elements and performing varying amounts of ligamentous decompression. Two principal forms have been described, including the “open door” and “French door” techniques. In a “French door” or “double door” laminoplasty, a midline opening is created with hemilamina hinged on either side,39 while the “open door” laminoplasty involves the creation of a unilateral opening with a contralateral hinge.38 These techniques are hypothesized to minimize the risk of progressive deformity by preserving the ligamentous and muscular complexes of the posterior elements. A recent randomized prospective study found similar neurologic outcomes and complication

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rates between the two subtypes, although French door laminoplasty resulted in more favorable postoperative cervical alignment and range of motion.40 Complications of laminoplasty are similar in scope to other posterior approaches, and include loss of lordosis, progressive kyphosis, and nerve root

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irritation. In our study, the laminoplasty cohort demonstrated the second highest rate of nerve root injury at 5.0%.

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In patients with multilevel OPLL with significant kyphotic deformity, combined anterior-posterior

approaches may be indicated in which both posterior decompression and/or stabilization and anterior

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column reconstruction or realignment are performed. While combined approaches were not assessed in our analysis, these have been studied to a limited extent in the literature with favorable results.41,42 Larger studies comparing this combined approach to more conventional single approach treatments are

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needed

Multiple studies have compared anterior and posterior approaches directly, and earlier comparativeeffectiveness studies largely favored anterior procedures based on neurologic outcome data. In 2002,

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Tani et al. found anterior patients to have better neurologic outcomes compared to the reported 33% rate of neurologic deterioration in their laminoplasty cohort.23 Masaki et al. also compared anterior and

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laminoplasty cohorts and found better neurologic recovery rates in the anterior group, particularly when compared to elderly patients undergoing laminoplasty.43 More recently, Kalb et al. compared four surgical procedures (anterior, laminectomy-fusion, laminoplasty, anterior-posterior) and concluded that while they could not identify specific indications for selecting a particular approach, anterior patients had the best neurologic outcomes.44 However, the numbers of patients in each cohort were exceedingly small, and while the anterior cohort had a highest average postoperative modified JOA (mJOA) score, the laminectomy-fusion cohort had the greatest absolute gain in average mJOA.

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In 2011, Hirai at al. conducted a prospective study comparing anterior and laminoplasty cohorts and also found superior rates of neurologic recovery in the anterior cohort but highlighted the caveat that

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laminoplasty was the safer procedure from a complications perspective.45 Subsequent comparative studies have continued the focus on complications. For example, Sakai et al. compared the floating anterior approach to laminoplasty and found the anterior cohort to have better JOA scores and less

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progression of disease than the laminoplasty cohort, but noted that all major operative complications were in the anterior cohort while the laminoplasty cohort had none.22 It is perhaps due to these reasons

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that some groups have preferred to utilize posterior surgical approaches initially when possible.

Lin et al. found that patients with >50% canal stenosis fared better from a neurologic perspective with anterior procedures at the expense of increased complications. Therefore, posterior decompressionfixation became the primary treatment for cervical OPLL with canal stenosis <50% at their institution, in

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an attempt to avoid the complications associated with anterior procedures.20 Likewise, Kawaguchi et al. described their institutional approach as laminoplasty in all OPLL patients unless there are major

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contraindications.46 Among 144 patients with more than three years follow-up, 8% required a subsequent (anterior) procedure, all of which resulted in good outcomes, which is in contrast to

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published re-operation rates as high as 26% in anterior cohorts.46,47

Building on these comparative studies, Xu et al. conducted a systematic review of the literature on surgical treatment of cervical OPLL and were unable to draw any conclusions regarding an optimal treatment strategy, but did make note that anterior approaches were associated with higher rates of complications.48 Similarly, our pooled analysis identified anterior surgery as having the highest complication rates. On the other hand, Li et al. conducted a systematic review of the complications

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associated with surgery for cervical OPLL.11 While they found a high overall complication rate (22%), they did not find a significant difference in the rate of complications between anterior and posterior procedures. Of note, they concluded that because complication rates associated with OPLL surgery

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were so much higher than those found in the surgical treatment of degenerative CSM, the risk of

surgical complications should play a role in surgical decision-making for OPLL patients.11 Interestingly, prospective studies comparing complication data for anterior versus posterior surgery for CSM in

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general demonstrate overall comparable rates,49 and there is considerable disagreement among

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surgeons regarding complication risk based on surgical approach.50

On review of the 52 papers included in this study, 49/52 (94%) studies tracked JOA/Nurick grades to measure myelopathy severity, but only 12/52 (23%) studies included other patient-reported outcomes to track pain and/or other disease-specific disability, and only one study utilized global HRQoL instruments (e.g. SF-36). Global HRQoL metrics have become routinely followed in outcomes studies on

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CSM and degenerative lumbar surgery, both in prospective registries and clinical trials.51–53 In fact, both the U.S-based National Neurosurgery Quality and Outcomes Database and the U.K. NICE quality

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registries.54,55

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improvement initiative have made the EQ-5D a standard outcome tool in their prospective surgical

While myelopathy scales should continue to be tracked to document patient improvement, they are not always indicative of surgical success. Patients with significant pre-operative myelomalacia may not demonstrate a meaningful change in JOA score, although a successful surgery may prevent the patient from deteriorating. Patients with Nurick grade 5 myelopathy have been shown to not make meaningful improvements in myelopathy scores, although it is unclear whether those patients would have deteriorated further without surgery.56 Likewise, the occurrence of serious complications in most

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patients will undoubtedly diminish quality of life but not be reflected in the outcome instruments currently being utilized.

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There are multiple limitations in the present study. The first limitation is the use of preference-based HRQoL measures from disparate resources, which we have used as a proxy for the OPLL disease state. Additionally, nominal utility and QALY values presented in this study overestimate the true overall

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HRQoL when compared to the literature on cervical and lumbar surgery and cannot be compared to values derived from other HRQoL instruments such as the EQ-5D or SF-6D. For example, post-operative

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EQ-5D scores following cervical fusion for degenerative conditions range from 0.6 to 0.82 in the published literature.57–59 Nevertheless, the relative values between the different surgical approaches are the relevant comparisons in this decision-analytic model.

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Additionally, and most importantly, surgical decision-making for OPLL-related myelopathy is often not an apples-to-apples comparison among different patients. Because of heterogeneity among patient characteristics and pathologic findings, situations of true clinical equipoise are difficult to ascertain.

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While we observed statistically significant divergence in 5-year QALYs, the overall difference in magnitude between laminoplasty and laminectomy alone was modest, underscoring the importance of

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patient-specific decision making regarding the surgical approach. While some of the included studies compared cohorts formulated by institutional practice (e.g. alternating anterior and posterior approaches by year), other series may have pre-operatively stratified surgical approach based on the pathology. Finally, heterogeneity among the experience of the treating surgeons cannot be controlled for and may influence complication rates.

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Despite the limitations, the results of this study may help guide decision-making in cases where multiple surgical approaches are feasible for a given patient. Our study and the comparative-effectiveness studies detailed above suggest that while neurologic scales are a logical choice for outcomes research on

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OPLL-related cervical myelopathy, HRQoL should not be ignored, especially when the most commonly utilized procedures have such high complication and re-operation rates. Moving forward, it may be useful to prospectively track HRQoL in patient registries on OPLL. The findings of this study and

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conclusions drawn from previous comparative-effectiveness studies on OPLL also highlight the need for

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future high-quality clinical trials in this disease.

Conclusion

Quality of life measures have become increasingly important for tracking outcomes in the spinal surgery

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literature. This study represents one of the first applications of HRQoL research to surgery for OPLLrelated cervical myelopathy. The results of this decision analysis suggest that: •

Anterior surgery is associated with the highest peri-operative complication rates in patients

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undergoing surgery for OPLL

Laminectomy alone was associated with the highest rate of revision surgery

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Laminoplasty may result in superior long term outcomes from a HRQoL perspective

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•

These findings may guide surgeons in cases where either procedure is a reasonable option. This study highlights the need to include prospectively collected HRQoL data in registries of OPLL patients and the need for high-quality clinical trials to compare surgical approaches.

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Acknowledgements: We would like to thank Mark A. Attiah and Paul R. Massey for their efforts in data acquisition.

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Conflict of Interest: There were no external sources of funding for this work. The authors have no relevant financial conflicts of interest to disclose.

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October 9, 2017. Yang S-C, Yu S-W, Tu Y-K, Niu C-C, Chen L-H, Chen W-J. Open-door laminoplasty with suture anchor fixation for cervical myelopathy in ossification of the posterior longitudinal ligament. J Spinal Disord Tech. 2007;20(7):492-498. doi:10.1097/BSD.0b013e318033e844. Yang H, Lu X, Wang X, et al. A new method to determine whether ossified posterior longitudinal ligament can be resected completely and safely: spinal canal "Rule of Nine" on axial computed tomography. Eur Spine J. 2015;24(8):1673-1680. doi:10.1007/s00586-014-3539-9. Yoshii T, Sakai K, Hirai T, et al. Anterior decompression with fusion versus posterior decompression with fusion for massive cervical ossification of the posterior longitudinal ligament with a ≥50% canal occupying ratio: a multicenter retrospective study. Spine J. 2016;16(11):13511357. doi:10.1016/j.spinee.2016.07.532. Yoshii T, Hirai T, Yamada T, et al. Intraoperative evaluation using mobile computed tomography in anterior cervical decompression with floating method for massive ossification of the posterior longitudinal ligament. J Orthop Surg Res. 2017;12(1):12. doi:10.1186/s13018-017-0515-1. Zhang T, Guo Y, Hu N, et al. Segmental Subtotal Corpectomy and Reconstruction With Titanium Cage and Anterior Plate for Multilevel Ossification of the Posterior Longitudinal Ligament. Orthopedics. 2016;39(6):e1140-e1146. doi:10.3928/01477447-20160819-07. Zhao X, Xue Y, Pan F, et al. Extensive laminectomy for the treatment of ossification of the posterior longitudinal ligament in the cervical spine. Arch Orthop Trauma Surg. 2012;132(2):203209. doi:10.1007/s00402-011-1420-4.

22

ACCEPTED MANUSCRIPT

Value

SD

Reference

None

1

0

Hunink, 200160

CSF leak requiring additional treatments

0.95

0

Estimate

Reoperation for CSF leak

.915

0

Lega, 201013

Reoperation for pseudoarthrosis, construct failure, or disease residual/progression

.915

0

Lega, 201013

Reoperation for hematoma

.915

0

Nerve root injury

.788

.194

Nayak, 201661

Spinal cord injury

.66

.19

Lee, 200862

Death

0

0

Hunink, 200160

Lega, 201013

M AN U

TE D

Table 2: Publications Used in the Analysis

RI PT

Complication

SC

Table 1: Utilities associated with perioperative complications

Year

N operated

Approach

Myelopathy Scale

Other PROMs

Baba63

1994

85

Anterior

JOA

No

Baba64

1995

Belanger65

2005

57

Laminoplasty

JOA

No

61

Anterior

Nurick

No

AC C

Chen66

EP

First Author

2009

83

Laminectomy+fusion

JOA

No

2009

138

Anterior

JOA

No

2011

22

Anterior

JOA

No

Chen17

2011

28

Laminectomy+fusion

JOA

No

Chen17

2011

25

Laminoplasty

JOA

No

Chen68

2014

229

Anterior

JOA

No

Chen67 Chen17

ACCEPTED MANUSCRIPT

2005

47

Anterior

Nurick

No

Choi24

2014

51

Laminoplasty

JOA

No

Choi 24

2014

23

Laminectomy+fusion

JOA

No

Fujimori25

2014

12

Anterior

JOA

VAS

Fujimori25

2014

15

Laminoplasty

JOA

Gu70

2015

64

Anterior

JOA/Nurick

Hou26

2017

150

Anterior

JOA

Hou26

2017

102

Laminoplasty

JOA

VAS

Iwasaki71

2002

92

Laminoplasty

JOA

No

Kato72

1998

52

Laminectomy

JOA

No

Kim73

2009

17

Anterior

JOA

No

Kim74

2015

71

Anterior

JOA

No

Kimura75

2012

150

Anterior

JOA

No

Koda27

2016

15

Anterior

JOA

No

Koda27

2016

17

laminectomy+fusion

JOA

No

Koda27

2016

16

Laminoplasty

JOA

No

Lee19

2008

20

Anterior

Nurick

No

Lee19

2008

27

Laminoplasty

Nurick

No

Lee28

2013

34

Laminectomy

JOA

No

2016

15

Laminectomy

JOA

NDI, VAS

2016

21

laminectomy+fusion

JOA

NDI, VAS

2016

21

Laminoplasty

JOA

NDI, VAS

Lei76

2016

24

Anterior

JOA

VAS

Li77

2017

42

Laminoplasty

JOA

NDI, VAS

Lee18 Lee18

VAS No

VAS

SC

M AN U

TE D

EP

AC C

Lee18

RI PT

Choi69

ACCEPTED MANUSCRIPT

2012

26

Anterior

JOA

No

Lin20

2012

30

Laminectomy+fusion

JOA

No

Liu78

2013

68

Anterior

JOA

No

Liu79

2013

146

laminectomy+fusion

JOA

VAS

Liu78

2013

59

Laminoplasty

JOA

Liu29

2017

25

laminectomy+fusion

JOA

Liu29

2017

26

Laminoplasty

JOA

Maruo80

2014

45

Laminoplasty

JOA

No

Mizuno81

2001

146

Anterior

None

No

Mizuno21

2006

111

Anterior

None

No

Mizuno21

2006

10

Laminoplasty

None

No

Morimoto82 2000

38

Laminoplasty

JOA

No

Odate83

2012

68

Anterior

JOA

No

Ogawa84

2004

139

Laminoplasty

JOA

No

Ohya85

2016

44

Laminoplasty

JOA

SF-36, NDI

Ota86

2016

23

Laminoplasty

JOA

No

Sakai22

2012

22

Anterior

JOA

No

Sakai22

2012

Sarkar87

2016

Satomi88

RI PT

Lin20

VAS, NDI

VAS, NDI

SC

M AN U

TE D

EP

No

Laminoplasty

JOA

No

138

Anteror

None

No

2001

106

Laminoplasty

JOA

No

Seichi89

2001

52

Laminoplasty

JOA

No

Sun90

2017

60

Anterior

JOA

VAS

Takayasu91

1999

12

Anterior

NCSS

No

Tani23

2002

14

Anterior

JOA

No

AC C

29

ACCEPTED MANUSCRIPT

2002

12

Laminoplasty

JOA

No

Yamaura33

1999

121

Anterior

JOA

No

Yang92

2007

27

Laminoplasty

Nurick, JOA

No

Yang93

2015

308

Anterior

JOA

No

Yoshii94

2016

33

Anterior

JOA

Yoshii95

2017

50

Anterior

JOA

Yuan30

2015

13

laminectomy+fusion

JOA

Yuan30

2015

20

Laminoplasty

JOA

VAS

Zhang96

2016

34

Anterior

JOA

No

Zhao97

2012

82

Laminectomy

SC

VAS

JOA

Laminectomy

TE D

Anterior floating

No

VAS

Laminectomyfusion

Laminoplasty

mean

SD

mean

SD

mean

SD

Age

56.44

3.89

57.63

1.05

60.118

4.03

57.56

5.36

Percent male

68.4

15.1

0.767

0.14

0.801

0.11

66.6

21.1

EP

Variable/Treatment

VAS

M AN U

Table 3: Demographics

RI PT

Tani23

5.017

0.35

4.68

0.67

4.88

0.67

2.34

AC C

Number of levels

0.42

mean

SD

ACCEPTED MANUSCRIPT

Table 4: Incidence of Peri-operative Complications Complications/Treatment

Anterior

Laminectomy

Laminectomy-fusion

Laminoplasty

SD

mean

SD

mean

SD

mean

SD

Death

0.004

0.002

0

0

0

0

0

0

CSF leak – operative repair

0.003

0.001

0

0

0

0

0

0

CSF leak – other treatment

0.047

0.006

0

0

0

0

0.014

0.006

Nerve root injury

0.036

0.004

0.027

0.008

0.068

0.013

0.050

0.007

Spinal cord injury

0.009

0.002

0.015

0.006

0.008

0.004

0.002

0.001

Intraspinal hematoma

0.012

0.004

0.019

0.008

0.021

0.009

0.020

0.009

Total complications

0.110

0.007

0.062

0.017

0.097

0.015

0.087

0.008

M AN U

SC

RI PT

mean

Table 5: Expected Utilities at 5 Year Follow-up Laminectomy SD

4.891

0.053

Lam-fusion

Laminoplasty

mean

SD

mean

SD

mean

SD

4.833

0.049

4.899

0.049

4.909

0.045

AC C

EP

mean

TE D

Anterior

ACCEPTED MANUSCRIPT

Highlights:

RI PT

SC M AN U TE D

• •

EP

•

Outcome prediction for surgical management of symptomatic ossification of the posterior longitudinal ligament (OPLL) remains challenging. The present decision analysis sought to determine health care quality of life among the various surgical approaches for OPLL using complication and quality of life data from the existing literature Anterior cervical approaches were associated with the highest complication rates Laminoplasty and laminectomy alone were associated with the highest and lowest long term quality adjusted life year, respectively

AC C

•

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

The authors have nothing to disclose