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Surgical Treatment of Cervical Spondylotic Myelopathy

Outcomes After Laminoplasty Compared With Laminectomy and Fusion in Patients With Cervical Myelopathy

A Systematic Review

Yoon, S. Tim MD, PhD*; Hashimoto, Robin E. PhD; Raich, Annie MPH; Shaffrey, Christopher I. MD; Rhee, John M. MD*; Riew, K. Daniel MD§

Author Information
doi: 10.1097/BRS.0b013e3182a7eb7c

The 2 most common posterior cervical surgical procedures for the treatment of cervical myelopathy are cervical laminoplasty and cervical laminectomy and fusion.1–7 Typically, these procedures are chosen in situations involving multilevel spinal cord compression with cervical myelopathy. Both procedures decompress the spinal cord by expanding the space available for the spinal cord, and both are generally thought to be effective. However, the procedures have significant differences. Cervical laminoplasty preserves the lamina and provides for spinal canal expansion by reshaping the lamina without fusion, whereas laminectomy and fusion expands the canal by removing the lamina entirely and relies on fusion to prevent postlaminectomy kyphosis. Contraindications for laminoplasty include significant kyphosis and instability due to trauma or even rheumatologic disease. Laminectomy and fusion may be preferred in situations where instability is problematic. However, in situations with fixed severe kyphosis, laminectomy and fusion alone is also problematic. Although there are strong proponents of either of the 2 procedures, there is very little clarity on which is more effective, safe, and whether there are any situations in which on procedure is clearly preferred compared with the other.

This report systematically evaluates the effectiveness and safety of cervical laminoplasty versus laminectomy and fusion in patients with cervical myelopathy due to spondylosis or ossification of the posterior longitudinal ligament (OPLL).

We will assess the outcomes of the procedures using various validated outcomes instruments, including the Japanese Orthopaedic Association (JOA) and modified Japanese Orthopaedic Association (JOA) scoring systems. In addition, we will assess the complications associated with the procedure, including instability, deformity, axial neck pain, and reoperation. To that end, we will address the following key clinical questions:

In adult patients with cervical myelopathy:

  1. What is the effectiveness of laminoplasty compared with laminectomy and fusion in the short and long term?
  2. What is the safety of laminoplasty compared with laminectomy and fusion?
  3. Is there evidence of differential efficacy or safety for laminoplasty versus laminectomy and fusion given certain subtypes of CSM, age, comorbidity, and baseline spinal deformity?

MATERIALS AND METHODS

Electronic Literature Search

A systematic search of PubMed/MEDLINE, the Cochrane Collaboration Library, and Google Scholar for literature published through October 5, 2012, was conducted. Only studies on humans, written in English and containing abstracts were considered for inclusion. The focus was on identification of studies explicitly designed to evaluate the effects of laminoplasty compared with laminectomy and fusion in patients with cervical myelopathic spondylosis (CSM). Details of the inclusion and exclusion criteria may be found in Table 1. The search strategy included use of controlled vocabulary (Medical Subject Headings [MeSH] terms) as well as key words. Terms specific to CSM included: cervical spondylotic myelopathy OR cervical myelopathy OR (cervical AND myelopathy) OR ossification of posterior longitudinal ligament [MeSH] OR ossification of posterior longitudinal ligament. They were combined with terms specifying the surgery ((Laminoplasty OR laminoplast* OR laminaplast*) AND (Laminectomy OR Laminectomy[MeSH])). Randomized controlled trials and high-quality cohort studies (class of evidence [CoE] I or II) comparing these 2 treatments for CSM were specifically sought. Because only one CoE II study was identified that met our inclusion criteria, we included cohort studies. As the focus of the key questions is comparative in nature, case series were excluded; case reports, meeting abstracts/proceedings, white articles, and editorials were additionally excluded. The PICO (participants, intervention, comparator, and outcomes) table provides additional information on inclusion/exclusion criteria (Table 1). We also hand-searched key references to identify any additional studies that were not found by our systematic literature search.

TABLE 1
TABLE 1:
PICO Summary of Inclusion and Exclusion Criteria

Data Extraction

The following demographic information was abstracted from each study: population, condition, details of each intervention, and follow-up information. Outcomes abstracted focused on those outcomes listed in our inclusion table (Table 1), namely: myelopathy scores (i.e., JOA/mJOA or Nurick scores), patient-reported pain outcomes (including the Neck Disability Index, and outcomes for neck, arm, and overall pain), and quality of life as reported by the Short-Form 36.

Study Quality and Overall Strength of Body of Literature

CoE ratings were assigned to each included article independently by 2 reviewers (R.H., A.R.) using criteria set by The Journal of Bone & Joint Surgery8 for therapeutic studies and modified to delineate criteria associated with methodological quality and risk of bias based on recommendations made by the Agency for Healthcare Research and Quality.9,10 The appraisal system used in this article accounts for features of methodological quality and important sources of bias by combining epidemiologic principles with characteristics of study design to determine the CoE and are consistent with those used in previous focus issues.11 See the Supplemental Digital Content available at http://links.lww.com/BRS/A829 for details on individual study ratings.

After individual article evaluation, the overall body of evidence with respect to each outcome is determined. The initial strength of the overall body of evidence was considered “high” if the majority of the studies were class I or II and “low” if the majority of the studies were class III or IV. The body of evidence may be downgraded 1 or 2 levels on the basis of the following criteria: (1) inconsistency of results, (2) indirectness of evidence, (3) imprecision of the effect estimates (e.g., wide confidence intervals), or (4) non-a priori statement of subgroup analyses. The body of evidence may be upgraded 1 or 2 levels on the basis of the following criteria: (1) large magnitude of effect or (2) dose-response gradient. The final overall strength of the body of literature expresses our confidence in the estimate of effect and the impact that further research may have on the results. An overall strength of high means we have high confidence that the evidence reflects the true effect. Further research is very unlikely to change our confidence in the estimate of effect. The overall strength of “moderate” means we have moderate confidence that the evidence reflects the true effect. Further research may change our confidence in the estimate of effect and may change the estimate. A grade of “low” means we have low confidence that the evidence reflects the true effect. Further research is likely to change the confidence in the estimate of effect and likely to change the estimate. Finally, a grade of “insufficient” means that evidence either is unavailable or does not permit a conclusion. The Supplemental Digital Content available at http://links.lww.com/BRS/A829 contains the details of how we arrived at the strength of evidence for each key question.

Data Analysis

We performed all analyses on an individual study level. For continuous outcome measures (e.g., JOA scores), we reported (or calculated if not calculated by the author) the mean change scores and standard deviations (SD). We imputed the change score SDs using a formula that includes pre- and post-SDs and a correlation coefficient coefficient of 0.80. Mean baseline, mean follow-up, mean change scores, and their respective SDs were entered into a database, and we calculated the standardized mean difference (SMD). SMDs were calculated by subtracting the mean change scores and dividing by the pooled change score SDs. This standardized method allowed us to compare the change (i.e., improvement or decline) in scores between laminoplasty and laminectomy and fusion by study. Cohen has reported an effect size of 0.2 to 0.3 as a “small” effect, around 0.5 as a “medium” effect and 0.8 to infinity as a “large” effect.12 To determine if the differences in change scores were significantly different, we conducted an unpaired t test using the change score means, SDs, and sample size. For dichotomous outcomes (e.g., axial pain rates), we reported the raw data and rates and calculated risk differences and relative risks and their 95% confidence intervals. Risk differences are calculated by subtracting the 2 rates, and relative risks are calculated by dividing 1 rate by another. We presented studies side by side in summary tables and figures to make a qualitative assessment of treatment effectiveness and harm. We performed all statistical analyses using Stata 9.1 (StatCorp LP, College Station, Texas).13

Clinical Recommendations and Consensus Statements

Clinical recommendations or consensus statements were made through a modified Delphi approach by applying the Grading of Recommendations Assessment, Development and Evaluation/Agency for Healthcare Research and Quality criteria that imparts a deliberate separation between the strength of the evidence (i.e., high, moderate, low, or insufficient) from the strength of the recommendation. When appropriate, recommendations or statements “for” or “against” were given “strong” or “weak” designations based on the quality of the evidence, the balance of benefits/harms, and values and patient preferences. In some instances, costs may have been considered. A more thorough description of this process can be found in the focus issue Methods article.

RESULTS

Study Selection

The search strategy yielded 305 potentially relevant citations; of these, 299 were excluded on the basis of title and/or abstract. Six were selected for full-text review. Two additional studies were excluded on the basis of full-text review for the following reasons: only one patient underwent laminoplasty (n = 1) and less than 10 patients were enrolled per treatment group (n = 1). A list of excluded articles can be obtained in the Supplemental Digital Content available at http://links.lww.com/BRS/A829. A total of 4 retrospective cohort studies14–17 were selected for inclusion (Figure 1), all of which were CoE III. Further details on the CoE rating for these studies can be found online in the Supplemental Digital Content available at http://links.lww.com/BRS/A829.

Figure 1
Figure 1:
Flowchart showing results of literature search.

The 4 included retrospective cohort studies enrolled between 26 and 121 patients and compared laminoplasty with laminectomy and fusion. Three studies limited inclusion to patients with multilevel CSM; of these, 2 studies15,16 reported a mean of 5 involved vertebrae, and 215,17 required a minimum of 3 involved vertebrae for enrollment. The fourth study evaluated patients with multilevel OPLL; at least 3 vertebrae and more than 40% of the spinal cord diameter were required to be affected for inclusion.14 Two studies reported similar length of symptom duration in both treatment groups,15,17 while 2 studies did not report the duration of symptoms.14,16 One study did not report baseline pain or function scores,17 and 2 studies reported comparable baseline function (as measured by the JOA or Nurick scales) in both treatment groups.14,15 In contrast, one study reported that patients who underwent laminoplasty had significantly worse baseline Nurick scores than did those in the laminectomy-fusion group (2.9 vs. 2.2, respectively; P < 0.05); conversely, laminoplasty patients had significantly better preoperative neck pain VAS pain scores than patients who underwent laminectomy and fusion (3.2 vs. 5.8, respectively; P < 0.01).16 In the studies of patients with CSM, a variety of different laminoplasty approaches were used: Heller et al15 used the open-door approach in 3 patients and the T-saw approach in 10 patients; Highsmith et al16 used the open-door approach; and Woods et al17 used the standard posterior approach. In the study of patients with OPLL, Chen et al14 used the unilateral or bilateral open-door approach (in 15 and 10 patients, respectively). Patients in the comparator groups were treated with laminectomy and instrumented fusion in all 4 studies. The mean age of enrolled patients was similar among the studies, with a mean age ranging from 56 to 63 years. Of the 3 studies14,15,17 that reported patient sex, there was a higher proportion of males than female subjects (range, 61%–85%). The mean length follow-up was in the range from 24 to 42 months in the 3 CSM studies,15–17 and was a minimum of 48 months in the OPLL study.14 Study limitations across all 4 articles included lack of independent or blind outcome assessment as well as an absence of adequate controlling for potential confounding variables.14–17 Three of the studies had follow-up rates less than 80%,14–16 and 3 had inadequate sample sizes.15–17 Finally, 2 of the studies did not employ comparable treatment for both groups.14,16 Detailed tables with information on the patient demographics, operative characteristics, and outcomes can be found in the Supplemental Digital Content available at http://links.lww.com/BRS/A829.

The effectiveness and safety of laminoplasty versus laminectomy and fusion are summarized here. Effectiveness outcomes of interest that were reported in the included studies were severity of myelopathy (as measured by the JOA or the Nurick scoring systems); pain (including axial pain, neck pain, and subjective improvement in pain); and radiographical sagittal alignment. None of the studies reported outcomes using the Neck Disability Index or quality of life outcomes such as the Short-Form 36. The commonly reported safety outcomes of interest included reoperation, infection, chronic neck pain, neurological complications, and kyphotic deformity. Unfortunately, none of the studies evaluated the differential effectiveness or safety of laminoplasty versus laminectomy and fusion based on subtypes of CSM, age, comorbidity, baseline spinal deformity, or any other subpopulations.

Effectiveness of Laminoplasty Versus Laminectomy and Fusion

Severity of Myelopathy: JOA Scores and Nurick Grade

Severity of myelopathy as measured by JOA scores was evaluated by 2 studies; one of which included patients with OPLL and the other, which assessed patients with CSM (Table 2). In a small study (N = 53), Chen et al14 found that patients with multilevel severe OPLL had significantly greater improvement in long-term JOA scores after laminectomy and fusion than those treated with laminoplasty (P < 0.0001): the difference in change scores resulted in an SMD of −2.02, which represents a “large effect.” In contrast, in patients with multilevel CSM, Highsmith et al16 found no difference in the long-term change in mJOA scores between treatment groups in a similarly small study (N = 56), with a 0 difference in change scores representing an SMD of zero.

TABLE 2
TABLE 2:
Studies Comparing Laminoplasty to Laminectomy and Fusion for CSM or OPLL: JOA and mJOA Scores (Higher Scores Correlate With Better Outcome)

Two studies of patients with multilevel CSM assessed severity of myelopathy as measured by Nurick scores (Table 3). Both studies reported no difference in the long-term change scores between the laminoplasty and laminectomy-fusion treatment groups.15,16

TABLE 3
TABLE 3:
Studies Comparing Laminoplasty to Laminectomy and Fusion for CSM: Nurick Grade (Lower Scores Correlate With Better Outcome)

Pain

All 4 studies reported pain measurements; in all cases, there was not a statistically significant difference in pain outcomes between the laminoplasty and laminectomy-fusion treatment groups.

In patients with multilevel severe OPLL, Chen et al14 found that there was no significant difference in the risk of long-term axial pain after laminoplasty compared with laminectomy and fusion, with a corresponding relative risk of 1.8 (95% confidence interval, 0.50–7.03; P = 0.35) (Table 4).

TABLE 4
TABLE 4:
Studies Comparing Laminoplasty to Laminectomy and Fusion for CSM or OPLL: Pain

In patients with multilevel CSM, Heller et al15 similarly found no difference in the risk of axial pain at a mean of 26 months follow-up between treatment groups, while 2 studies17 found no differences in the risk of patient-perceived lack of pain improvement at approximately 2 years’ follow-up between the laminoplasty and laminectomy-fusion treatment groups (Table 4). One of these studies additionally reported no difference in the incidence of substantial debilitating neck pain between the laminoplasty (8% [3/39]) and laminectomy-fusion groups (2% [2/82]) (P = 0.066).17 Finally, there was no difference between treatment groups in pain improvement as measured by the Robinson scale15 and the VAS for neck pain16 (Table 5).

TABLE 5
TABLE 5:
Studies Comparing Laminoplasty to Laminectomy and Fusion for CSM or OPLL: Pain Outcome Measures (Lower Scores Correlate With Better Outcome)

Comparative Safety of Laminoplasty Versus Laminectomy and Fusion

Reoperation

Two of the 3 studies that reported reoperation rates found that patients treated with laminoplasty had lower reoperation rates than did those who received laminectomy and fusion, with rates of 0% versus 15%,15 13% versus 27%,16 and 5% versus 4%,17 respectively. Causes of reoperation included wound revision surgery, hardware malposition, stenosis, persistent radiculopathy, subjacent degeneration, inadequate decompression, and progressive kyphosis. Details are available in Table 6.

TABLE 6
TABLE 6:
Reoperation Rates After Laminoplasty Versus Laminectomy and Fusion Surgery for CSM or OPLL

Infection

In general, infection rates were slightly lower in patients treated with laminoplasty than those who received laminectomy. Deep infection after laminectomy and fusion occurred in 8% and 1% of patients as reported by 2 studies,15,17 whereas no deep infections were reported in the laminoplasty groups. Another study16 reported that wound infections occurred in 15% of patients who received laminectomy and fusion patients and in 7% of patients who underwent laminoplasty. Overall, there was one case of infection requiring surgical washout and closure across the laminoplasty treatment groups compared with 6 cases across the laminectomy-fusion treatment groups.15–17 Details are available in Table 7.

Neurological Complications

Chen et al14 reported higher rates of neurological deterioration after laminoplasty than laminectomy and fusion in patients with multilevel severe OPLL (16% vs. 0%, respectively). The same study also reported that the incidence of C5 palsy was lower after laminoplasty (8% vs. 14%, respectively)14; whereas another study reported rates of transient C5 paresis in patients with multilevel CSM of 3% vs. 0%,17 respectively (Table 7).

TABLE 7
TABLE 7:
Postoperative Complication Rates Comparing Laminoplasty to Laminectomy and Fusion Surgery for CSM or OPLL

Nonunions

All 3 studies of patients with CSM found pseudarthrosis occurred in a range of 1% to 38% of patients up to 2 years after laminectomy and fusion (Table 7).15–17

Kyphosis

Two studies reported on kyphotic deformitiy. In patients with severe multilevel OPLL, there were 4 cases of progressive kyphotic deformity in the laminoplasty group and none in the laminectomy-fusion group (16% vs. 0%, respectively) as reported by one study.14 In contrast, in patients with multilevel CSM, one study found lower rates of kyphotic deformity after laminoplasty than laminectomy and fusion (0% vs. 15%, respectively).

Evidence Summary

The overall strength of the evidence of the effectiveness of laminoplasty versus laminectomy and fusion in patients with CSM is “low,” that is, there is a low confidence that the evidence reflects the true effect, and further research is likely to change the confidence in the estimate of effect and likely to change the estimate. The overall strength of the evidence of the effectiveness of laminoplasty versus laminectomy and fusion in patients with OPLL is “insufficient,” that is, the available evidence does not permit a conclusion. The overall strength of the evidence of the effectiveness of laminoplasty versus laminectomy and fusion in patients with CSM or CSM is insufficient, that is, the available evidence does not permit a conclusion. The overall strength of the evidence of the differential efficacy or safety of laminoplasty compared with laminectomy and fusion was insufficient, that is, no evidence was available. Full details are available in Table 8.

TABLE 8
TABLE 8:
Strength of Evidence Summary

DISCUSSION

Paucity of Comparative Data

Despite the large number of studies on the topic of laminoplasty and laminectomy and fusion (more than 300), there are very few articles that compare the 2 groups within a single study (4). All 4 articles were retrospective cohort studies (CoE III). There was a mix of different types of laminoplasty techniques. It is possible that laminoplasty technique could influence the outcome, but given the small number of studies available to answer our questions, we had to group the articles together, which is a limitation of this study. Because of the limitations of the literature that we reviewed, we are unable to compare relative contraindications of laminoplasty and laminectomy and fusion. Given the diversity of opinions by surgeons on the preferred surgical approach of multilevel cervical stenosis causing myelopathy, there is a strong need for better literature to address the comparative advantages of the 2 different procedures.

Myelopathy Improvement in the Long Term

Three out of 4 articles indicate that there is no difference in the improvement of myelopathy between treatment groups. This indicates that the question of which procedure is more effective in treating cervical myelopathy remains unclear. However, one cannot conclude that either laminoplasty or laminectomy and fusions can be used with equal outcome given any circumstance. The studies that form the basis of this systematic review are not randomized controlled studies. In fact, surgeons chose either laminoplasty or laminectomy and fusion as they thought was best. Therefore, the patient populations that were compared have significant differences that swayed the surgeon to pick one procedure compared with the other.

Secondary Outcome Measures

There are fewer reoperations and fewer infections with laminoplasty than laminectomy and fusion. By definition, there cannot be any nonunions with laminoplasty. This is in contrast to a nonunion rate of 1% to 38% with laminectomy and fusion. The data were inconclusive with regards to postoperative pain, neurological complications, and kyphosis.

Illustrative Cases

We have provided illustrated cases of successful laminoplasty (Figure 2A–C), failed laminoplasty (Figure 3A–E), successful laminectomy and fusion (Figure 4A–C), and a failed laminectomy and fusion (Figure 5A–C).

Figure 2
Figure 2:
Successful laminoplasty case: 59-year-old female with clinical myelopathy that was progressive with no neck pain. She has preserved cervical lordosis on neutral lateral radiograph and multilevel stenosis with cord compression. She had an open-door laminoplasty with plates. Postoperatively, she maintained good cervical range of motion, minimal neck pain complaints, and continued cervical lordosis. Preoperative lateral radiograph (A); preoperative midsagittal MRI (B); postoperative lateral radiograph (C). MRI indicates magnetic resonance imaging.
Figure 3
Figure 3:
Failed laminoplasty case: A 55-year-old male with a history of myelopathy had laminectomy of C3 and laminoplasty of C4, C5, and C6. Postoperatively, he had good neurological improvement, however, he had significant neck pain. He then developed complaints of severe left arm pain, numbness, and weakness for 4 months. MRI showed disc protrusions on the left side from C3–C7 with the right protrusion greater than left protrusion at C3–C4. After he failed nonoperative treatment, he was treated with a C4–C7 decompression and fusion with relief of his symptoms. He is presently 6 weeks postoperation with complete resolution of his neck and arm pain. Preoperative lateral radiograph (A); postoperative lateral radiograph after index procedure (B); postoperative MRI at 3 years postoperatively showing disc herniations (C, D); lateral radiograph at 6-week-postoperative fusion C5 corpectomy, C6–C7 anterior cervical discectomy and fusion (second surgery) (E). MRI indicates magnetic resonance imaging.
Figure 4
Figure 4:
Successful laminectomy and fusion case: 64-year-old male with significant clinical evidence of cervical myelopathy. His preoperative neutral lateral radiograph demonstrates mild cervical kyphosis. His MRI shows a congenitally narrowed canal, multilevel cord compression, and T2 hyperintense signal at C5–C6. He underwent C3–C7 laminectomy and fusion with slight improvement in overall alignment to neutral, consistent with the alignment seen on his recumbent sagittal MRI. Preoperative lateral radiograph (A); preoperative midsagittal MRI (B); postoperative lateral radiograph (C). MRI indicates magnetic resonance imaging.
Figure 5
Figure 5:
Failed laminectomy and fusion case: A 62-year-old patient with cervical spondylotic myelopathy was initially treated successfully with laminectomy and fusion C5–T1. One and half years postoperatively, the patient developed adjacent segment degeneration at C4–C5 with spondylolisthesis, stenosis, and return of myelopathy. A nonunion at the C7–T1 level with a broken T1 screw was noted. The second surgery consisted of anterior cervical discectomy and fusion of C4–C5, laminectomy of C3–C5, extension of the fusion superiorly to C2 and inferiorly to T2, and posterior instrumentation of C2–T2. Lateral cervical radiograph 1.5 years after index surgery (A); midsagittal reformat of a cervical spine CT-myelogram (B); lateral cervical radiograph after second surgery (C). CT indicates computed tomography.

Evidence-Based Clinical Recommendations.

Recommendation. For CSM, evidence suggests that laminoplasty and laminectomy-fusion procedures can be similarly effective. We suggest that surgeons consider each case individually and take into account their own familiarity and expertise with each procedure.

Overall Strength of Evidence. Low

Strength of Recommendation. Weak

Key Points

  • A systematic review of the literature of studies that compare outcomes of laminoplasty to laminectomy and fusion for the treatment of cervical myelopathy identified retrospective cohort studies that met our inclusion criteria.
  • Taken together, the data from these studies suggests that laminoplasty and laminectomy and fusion procedures are similarly effective in treating CSM as measured by myelopathy scores and pain outcome measures.

Acknowledgments

The authors thank Nancy Holmes and Ms. Chi Lam for their administrative assistance.

Author contributios are as follows: T.Y.: Study concept, manuscript preparation, manuscript revision, and data analysis and interpretation; provided illustrative case (Figure 2); R.H.: Manuscript preparation, manuscript revision, and data analysis and interpretation; A.R.: Manuscript preparation, manuscript revision, and data analysis and interpretation; C.S.: Study concept; provided illustrative; manuscript revision, case (Figure 5); J.R.: Study concept, case images; manuscript revision, provided illustrative case (Figure 4). D.R.: Manuscript revision, study concept, provided illustrative case (Figure 3).

Supplemental digital content is available for this article. Direct URL citations appearing in the printed text are provided in the HTML and PDF version of this article on the journal's web site (www.spinejournal.com).

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Keywords:

cervical laminoplasty; cervical laminectomy and fusion; JOA; mJOA; Nurick; reoperation; infection; complication; outcome; comparative outcome

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