Authors: Ke Zhang, Zhencheng Xiong, Yuhao Zhang, Ziyi Zhuang, Sizhen Zhan, Mingsheng Tan, Ping Yi
Categories: Research, Cervical spine surgery, Axial symptoms, Meta-analysis, Risk factors
Source: BMC Surgery
Authors: Ke Zhang, Zhencheng Xiong, Yuhao Zhang, Ziyi Zhuang, Sizhen Zhan, Mingsheng Tan, Ping Yi
Axial symptoms are a frequent complication after posterior cervical spine surgery.While literature has documented risk factors for these symptoms, they are still debated. This study’s objective was to explore the risk elements associated with axial symptoms following posterior cervical spine surgery.
Our search encompassed The Cochrane Library, PubMed, Embase, and web of science databases, focusing on studies documenting complications related to cervical laminectomy and laminoplasty. In every study included, we documented axial symptom occurrences and computed Odds Ratios (ORs), 95% confidence intervals (Cls), Q values, and 12 values.
Nineteen different studies were finally included, and a summary of the key risk and protective factors identified in the included studies is provided preoperative neck pain (OR = 2.22,95%CI (1.48,3.33), P = 0.0001), facet joint destruction(OR = 2.32,95%CI (1.59,3.39),P < 0.0001), C2involvement(OR = 3.78,95%CI(2.04,7.01), P < 0.0001),C7spinous process (muscle) destruction (OR = 3.38,95%CI (1.13,10.08),P = 0.03), conventional posterior cervical spine surgery (OR = 6.18,95%CI (2.43,15.69),P = 0.0001) protective factors were as Increase range of motion after cervical spine surgery (OR = 0.64,95%CI (0.44,0.92), P = 0.02), enlargement of the preoperative C2-7 Cobb angle (OR = 0.57,95%CI(0.39,0.82),P = 0.003).
Preoperative neck pain, facet joints destruction, C7 spinous process(muscle)destruction, conventional posterior cervical spine surgery and C2 involvement were risk factors for postoperative axial symptoms after posterior cervical spine surgery, and a larger preoperative C2–C7 Cobb angle and increased postoperative cervical range of motion were protective factors for postoperative axial symptoms, however, gender, age, operation time, JOA score, C2-7 SVA, blood loss, and types of disease were not associated with postoperative axial symptoms. Considering the scarce volume of research available, this inference demands careful interpretation and necessitates expanded studies.
The online version contains supplementary material available at 10.1186/s12893-025-03074-6.
Since the clinical syndrome of spinal cervical spondylosis was established in the 1950 s, various surgical treatments have achieved extensive efficacy [1]. It is well known that cervical decompression surgery, including both anterior and posterior surgery, is a commonly used and effective procedure for the treatment of cervical spondylotic myelopathy(CSM). Posterior cervical spine surgery (including laminectomy and laminoplasty) has been shown to be an effective treatment for multisegmental CSM but is affected by various complications [2]. Axial pain, defined as pain from the neck to the periscapular or shoulder region, is a relatively common complication that occurs after posterior cervical spine surgery [3]. Hosono et al. [3] described a 60% incidence of axial symptoms after laminoplasty, and the incidence of axial symptoms was significantly higher after laminoplasty than after anterior surgery. The pathogenesis of axial symptoms after posterior cervical spine surgery has not been fully elucidated. Many risk factors, such as injury to the paraspinal muscles, evaluation of radiologic factors, gender, age, and preoperative neck pain, are associated with the development of axial symptoms after posterior cervical spine surgery [4, 5]. Although previous reviews, such as the systematic analysis by Wang et al. [6], have explored the incidence, potential causes, and preventive strategies for axial pain after posterior cervical spine surgery, their conclusions were primarily qualitative due to methodological limitations and clinical heterogeneity. Furthermore, their literature scope was restricted to studies published before 2010, limiting applicability to current surgical practices.Numerous studies [7–9], such as those focusing on a small sample, have detailed potential contributing factors to axial symptoms from posterior cervical spine surgery, yet their findings differed and weren’t subjected to a comprehensive central analysis.Meta-analysis, as an excellent method of statistical analysis, is able to efficiently incorporate the results of multiple studies and to resolve the conflicting reports and uncertainties that exist. Hence, this research undertook a comprehensive meta-analysis to analyze axial symptom risks post posterior cervical spine surgery, aiming to furnish clinically proven evidence for pinpointing high-risk categories.
An automated exploration of databases like The Cochrane Library, PubMed, Embase, and the web of science was carried out to gather research on the risk elements for axial symptoms posterior cervical spine surgery, spanning from its inception to March 1, 2024. A literature exploration was conducted by merging subject terms with free words connected through Boolean logic mechanisms.The search terms axial pain, neck pain, axial symptoms, cervical, cervical surgery, posterior cervical spine surgery, posterior approach, laminoplasty, laminectomy, single door, risk factors, influence factors, predicted factors, relevant factors, dangerous factors, factors, etc. while manually searching for references to be included in the literature for supplementation. English was the only language selected for the search, with a strategy formulated through numerous preliminary searches.
The inclusion criteria are summarised (1) studies based on case-control or cohort analyses; (2) articles referring to posterior or anterior-posterior access; and (3) articles that included at least the results of one-way analyses incorporating the outcome metrics, provided the outcome odds ratio (OR) values with 95% confidence intervals (CI) from multifactorial logistic regression analyses, or were able to calculate the OR values with 95% CIs from the literature data. The criteria for exclusion were outlined (1) literature with duplicate data publication. When a single author from the same organization reported the article, the literature with the most recent report and comprehensive clinical data was chosen, whereas if an identical number of cases were documented by the same author, the article with the most detailed information was picked. (2) dissertations, case reports, conference abstracts, letters, Meta-analyses and review literature. (3) data could not be extracted, correlates could not be combined, results were unclear, the quality of the literature was poor (NOS < 5 points), and the original article was not available. (4) studies mentioning only anterior surgery or unspecified surgical modalities were applied to the treatment. (5)studies in non-English languages.
Firstly, Endnote 21.0 was used to screen the retrieved literature, and then 2 researchers were allowed to screen the study according to the inclusion criteria and exclusion criteria, and extract the data information through Excel, and if there were any differences after cross-checking, a third researcher would discuss and judge the final results together. The data extraction table should (1) basic information of the primary writer, publication year, study area, type of study, and follow-up time; (2) traits of the research sample size (case and control groups), gender ratio, type of disease, surgical procedure, and mode of axial pain assessment; and (3) outcome factors contributing to axial symptoms and the related odds ratios, accompanied by 95% confidence intervals.
The NOS Literature Quality Rating Scale recommended by the Cochrane Collaboration Network was used to evaluate the risk of literature bias, including three modules (selection of study population, comparability between groups, and outcome evaluation), with a total of 8 entries and a score of 9 out of 9, of which ≥ 7 was classified as high-quality studies, 4 ~ 6 were classified as medium-quality studies, and ≤ 4 were classified as low-quality studies [10]. Literature quality was evaluated by 2 researchers, and if there was disagreement after cross-checking, it was verified by a third researcher.
Meta-analyses were performed applying RevMan 5.4 software (Cochrane Collaboration, Oxford, UK) and STATA 15.0 (Stata Corporation, College Station, TX). The ratio of ratios (OR) was used as an effect indicator for the analysis of dichotomous variables, and the standardized mean difference (SMD) was used as an efficacy analysis statistic for the analysis of continuous variables, both of which provided 95% confidence intervals. Statistical heterogeneity of included trials was tested using quantitative I^2^ values, with no heterogeneity ranging from 0 to 25%, low heterogeneity ranging from 26-50%,moderate heterogeneity ranging from 51 to 75%, and high heterogeneity ranging from > 75% [11]. If P > 0.1, I^2^ < 50%,it suggests homogeneity across different studies, then the fixed-effects model is used to combine statistics, when P ≤ 0.1 and I^2^ ≥ 50%, suggesting inter-study heterogeneity, a random effects model was utilized.Given the moderate heterogeneity observed in the included studies, we still chose to use a random effects model.In cases of borderline heterogeneity or when only a small number of studies were available (e.g., n ≤ 2), we used statistical modelling of change to assess the stability of the portfolio results and, if unstable, further excluded literature on a case-by-case basis for sensitivity analysis.We applied fixed and random effects model systematically rather than selectively, based on I² values and study counts for each outcome.To evaluate publication bias, we employed techniques like funnel plot, harbord, egger tests, and the trim and fill method. A test result of P < 0.05 was deemed to hold statistical significance.
Initially 617 documents were obtained by computer searching 4 databases, after excluding duplicates, 598 documents were obtained by initial screening, 18 studies were obtained after reading titles and abstracts, 1 study was unable to access the original text, 8 failed to fulfill the criteria for exclusion and consequently were omitted, 10 were included again after carefully reading the references of the studies, and 19 were finally incorporated in line with the literature of Meta analysis. Figure 1 illustrates the particular procedure and screening approach used.
Fig. 1Screening process and methodology
Nineteen articles were incorporated into this comprehensive meta-analysis involving 2,136 posterior cervical spine surgeries, and the number of patients who developed postoperative axial symptoms was 646, with an overall incidence rate of 30.24%.Nine were case-control studies and 10 were cohort studies, and the NOS scores indicated that the inclusion was of medium- to high-quality studies (≥ 6 points).The fundamental traits of the studies included are displayed in Table 1.
Table 1Characteristics of the 19 included studiesReferenceYearDesignN (case group)N (control group)Influence factorsAxial Symptoms Assessment ModalityFollow up time(mon)Ruan CY [12]2023Case controlstudy106158Opening angle, Sex, Age, Postoperative cervical range of motion, C7 spinous process muscle endpoint damage, Facet joints destruction, Cervical curvature(C2–7Cobb angle)criteria based on Hosono19.5 ± 6.8Zuo KK [13]2022Case controlstudy38103C2-7SVA, C2involvementself-reported questionnaire23.3 ± 2.7Chen KW [14]2022Cohort study21101C2involvement, Preoperative axial paincriteria based on Hosono12Zhang X [15]2020Case controlstudy87162Sex, Operation time, Smoking, Preoperative neck pain, Collar wear time, C2 -C7SVA, Blood loss, Preoperative JOAself-reported questionnaire24Oshima Y [16]2018Cohort study2578Sex, Preoperative neck pain, Mental Component Summaryself-reported questionnaire24Kimura A [17]2018Cohort study51105Preoperative neck pain, Smoking, Mental component summarycriteria based on Gerbershagen24Chen H [18]2015Case controlstudy3990Sex, Blood loss, Preoperative neck pain, C2–7 Cobb angle, Preoperative JOA, Postoperative cervical range of motion, Facet joints destructioncriteria based on Yoshida M33.3Liu Y [19]2016Cohort study4161Sex, Age, Conventional laminoplasty, Operating time, Blood loss, Preoperative JOA, Preoperative neck pain, C2–7 Cobb angle, C2–7SVAcriteria based on Hosono6–8Cho CB [20]2010Cohort study1318C7 spinous process muscle endpoint damagecriteria based on Hosono28.90 ± 23.99Fujibayashi S [21]2010Case controlstudy316Sexcriteria based on Hosono12Kato M [22]2008Cohort study17128Conventional laminoplasty、C2 involvement, C7 spinous process destruction, Postoperative cervical range of motionself-reported questionnaire24Yoshida M [23]2002Case controlstudy25148Postoperative JOA scoreself-reported questionnaireMinimum 6Motosuneya ] [24]2011Cohort study5223Types of disease, Postoperative cervical range of motioncriteria based on Hosono152Chiba K [25]2006Cohort study2159Types of diseaseNot mentioned170.4Hosono N [26]2006Case controlstudy1065C7 spinous process destructioncriteria based on Hosono12Lin W [27]2023Case controlstudy1155Conventional laminoplastyNot mentioned12–24Kawaguchi Y [4]2003Case controlstudy1937Conventional laminoplastyself-reported questionnaire28.8Takeuchi K [28]2005Cohort study3224Conventional laminoplastyself-reported questionnaire30Shiraishi T [29]2003Cohort study3559Conventional laminoplastyNot mentioned24–66
The NOS rating scale was employed to assess the caliber of the 19 studies, with 3 studies scoring 8, 9 studies scoring 7, and 7 studies scoring 6, Table 2.
Table 2Quality assessment of the studiesReferenceSelectionComparabilityExposure/outcomeTotal scoreRuan CY4138Zuo KK3227Chen KW3227Zhang X3227Oshima Y4127Kimura A4217Chen H3227Liu Y3238Cho CB3227Fujibayashi S2226Kato M5128Yoshida M2226Motosuneya T3126Chiba K3126Hosono N2226Lin W3227Kawaguchi Y2226Takeuchi K2226Shiraishi T2237
Six studies [12, 15, 16, 19, 21, 22] reported gender differences, with moderate heterogeneity (p = 0.02, I2 = 64%). Our approach involved the application of a random effects model and the results demonstrated no significant difference(OR = 0.87, 95% CI (0.48,1.58),P = 0.64), Fig. 2.
Fig. 2Meta-analysis of the effect of gender on axial symptoms after posterior cervical spine surgery
Two studies [12, 19] reported differences in age. There was a large heterogeneity (P = 0.04, I^2^ = 77%), Our approach employed a random effects model, and the aggregated outcomes indicated that age did not hold statistical significance (OR = 0.17, 95% CI (0.00,41.19), P = 0.53), Fig. 3.
Fig. 3Meta-analysis of the effect of age on axial symptoms after posterior cervical spine surgery
Five studies [14, 15, 17–19] mentioned the effect of preoperative neck pain. The test for heterogeneity shows no notable significance (P = 0.16, I^2^ = 39%). To account for the variability across studies, a random-effects model was used for the analysis. cThe combined results suggested that preoperative neck pain remained a significant risk factor for axial symptoms (OR = 2.25, 95% CI (1.30, 3.89), P = 0.004), as shown in Fig. 4.
Fig. 4Meta-analysis of the effect of preoperative neck pain on axial symptoms after posterior cervical spine surgery
Two studies [12, 19] mentioned the difference of preoperative C2-7Cobb angle.The heterogeneity test showed that the heterogeneity was low (P = 0.58, I^2^ = 0%). The analysis was conducted using the fixed effect model and the combined results showed that the increase in the preoperative C2-7 Cobb angle was a protective factor (OR = 0.57,95% CI (0.39,0.82), P = 0.003), Fig. 5.
Fig. 5Meta-analysis of the effect of C2–7 Cobb angle on axial symptoms after posterior cervical spine surgery
The effect of smoking on the axial symptoms following posterior cervical spine surgery was mentioned in two studies [15, 17]. For smoking, There was no heterogeneity(P = 0.21, I^2^ = 35%), a fixed-effects model with OR = 1.81,95% CI (1.04,3.15), P = 0.04, a random-effects model was used for combined analysis with OR = 1.86, 95% (0.93,3.73), P = 0.08.The combined results of the 2 models were unstable, and the inclusion of only 2 papers in the literature precluded the performance of combined analyses. It is questionable whether smoking is associated with the occurrence of axiality after posterior cervical spine surgery, Fig. 6.
Fig. 6Meta-analysis of the effect of smoking on axial symptoms after posterior cervical spine surgery
Two studies [15, 19] mentioned the effect of operation time on the axial symptoms following posterior cervical spine surgery. Operation time exhibited no heterogeneity(P = 0.63, I^2^ = 0%), and the results of the fixed effect model revealed that the operation time was not correlated with the axial symptoms following posterior cervical spine surgery (OR = 1.01,95%CI(0.99,1.02),P = 0.33), Fig. 7.
Fig. 7Meta-analysis of the effect of operation time on axial symptoms after posterior cervical spine surgery
Two studies [19, 22] mentioned the association between preoperative JOA score and the axial symptoms following posterior cervical spine surgery. There was no significant heterogeneity (P = 0.72, I^2^ = 0%), and the fixed-effects model revealed that, concerning the link between the preoperative JOA score and the manifestation of axial symptoms, statistical significance was not observed (OR = 0.74, 95% CI (0.39,1.43), P = 0.38), as shown in Fig. 8.
Fig. 8Meta-analysis of the effect of preoperative JOA score on axial symptoms after posterior cervical spine surgery
Two studies [18, 23] referred to the relationship between postoperative JOA score and axial symptoms following posterior cervical spine surgery. The heterogeneity was slightly larger (P = 0.03, I^2^ = 79%). The results from the random effects model showed that the postoperative JOA score was not associated with the axial symptoms following posterior cervical spine surgery (SMD=−0.13,95% CI (−0.76,0.50), P= 0.68), Fig. 9.
Fig. 9Meta-analysis of the effect of postoperative JOA score on axial symptoms after posterior cervical spine surgery
Two studies [12, 18] mentioned the effect of facet joints destruction on the axial symptoms following posterior cervical spine surgery. There was no notable heterogeneity among the groups of studies (P = 0.93, I^2^ = 0%), and the combined results of meta-analysis using a fixed-effects model showed that facet joints destruction was a risk factor (OR = 2.32, 95% CI (1.59,3.39), P < 0.0001), Fig. 10.
Fig. 10Meta-analysis of the effect of facet joints destruction on axial symptoms after posterior cervical spine surgery
Four studies [12, 18, 22, 25] mentioned the effect of postoperative cervical range of motion on the axial symptoms following posterior cervical spine surgery. There was a large heterogeneity (P < 0.00001,I^2^ = 92%), and after excluding one study [25] by sensitivity analysis, no heterogeneity across studies (P = 0.91, I^2^ = 0%), and Fixed-effects model showed that increased postoperative cervical spine range of motion was a protective factor for axial symptoms(OR = 0.64, 95% CI (0.44,0.92), P = 0.02), Fig. 11.
Fig. 11Meta-analysis of postoperative range of motion on axial symptoms after posterior cervical spine surgery
Three studies [13, 14, 22] mentioned the effect of C2 involvement on the occurrence of axial symptoms after posterior cervical spine surgery.There was almost no heterogeneity among the studies (P = 0.29, I^2^ = 19%). The meta-analysis employed a fixed-effects model, revealing that C2 involvement following posterior cervical spine surgery posed a risk for axial symptoms (OR = 3.78, 95% CI (2.04,7.01), P < 0.0001), Fig. 12.
Fig. 12Meta-analysis of C2 involvement on axial symptoms after posterior cervical spine surgery
Three studies [13, 15, 19] reported the effect of C2-7 SVA on the occurrence of axial symptoms after posterior cervical spine surgery. The heterogeneity between studies was moderate (P = 0.04, I^2^ = 68%). Meta-analysis using a random effects model showed no association between C2-7 SVA and the occurrence of axial symptoms following a surgery on the posterior cervical spine(OR = 1.06, 95% CI (0.93,1.10), P = 0.75), Fig. 13.
Fig. 13Meta-analysis of C2-7 SVA on axial symptoms after posterior cervical spine surgery
Two studies [16, 17] mentioned the effect of mental component summary on the occurrence of axial symptoms after posterior cervical spine surgery. Heterogeneity between the 2 studies was moderate (P = 0.08, I^2^ = 67%),Meta-analysis using the random-effects model showed OR = 1.40, 95% CI (0.74,2.67), P = 0.30, and the combined result was OR = 1.12, 95% (1.05, 1.19), P = 0.001 when using the fixed-effects model. The combined result with the 2 models was The combined results were unstable, and with only 2 papers included in the literature, it was not appropriate to combine the analyses, so it is questionable whether mental component summary is associated with the axial symptoms, Fig. 14.
Fig. 14Meta-analysis of mental component summary on axial symptoms after posterior cervical spine surgery
Four studies [12, 20, 22, 26] mentioned the effect of C7 spinous process(muscle) destruction on the occurrence of axial symptoms following a surgery on the posterior cervical spine. There was a moderate heterogeneity observed among the studies (P = 0.03, I^2^ = 65%). A random effects model was used for meta-analysis. The comprehensive research results showed that C7 spinous process (muscle) destruction was a risk factor (OR = 3.38, 95% CI(1.13,10.08),P = 0.03), Fig. 15.
Fig. 15Meta-analysis of C7 spinous process (muscle) destruction on axial symptoms after posterior cervical spine surgery
Two studies [12, 15] reported the effect of collar wear time.Meta-analysis using a random effects model resulted in OR = 1.08, 95% CI (0.55, 2.12), P = 0.82, however, a combined analysis using a fixed effects model resulted in OR = 0.85, 95% (0.74, 0.98), P = 0.02. The combined results of the 2 models were unstable, and only 2 papers were included in the literature, making it inappropriate to perform a combined analysis, so it is doubtful whether collar wear time is related to the occurrence of axiality after posterior cervical spine surgery, Fig. 16.
Fig. 16Meta-analysis of collar wear time on axial symptoms after posterior cervical spine surgery
Two studies [19, 22] mentioned the impact of blood loss. there was no heterogeneity between the 2 groups of studies (P = 0.94, I^2^ = 0%), and a fixed-effect model showed that the association between blood loss and the axial symptoms was not statistically significant (OR = 1.02, 95% CI (0.98,1.06), P = 0.37), Fig. 17.
Fig. 17Meta-analysis of blood loss on axial symptoms after posterior cervical spine surgery
Three studies [22, 24, 25] referred to the effect of types of disease (including spondylotic cervical spondylosis and ossification of the posterior longitudinal ligament) on the axial symptoms. There was heterogeneity in types of disease (P = 0.09, I^2^ = 59%), and the random effects model showed that types of disease was not statistically significant (OR = 0.69, 95% CI (0.27,1.76), P = 0.44), Fig. 18.
Fig. 18Meta-analysis of types of disease on axial symptoms after posterior cervical spine surgery
Five studies [4, 19, 27–29] mentioned the effect of conventional posterior cervical spine surgery versus modified posterior cervical spine surgery on the occurrence of axial symptoms after posterior cervical spine surgery. For disease type, after heterogeneity test (P = 0.05, I^2^ = 59%), the random effects model was used, and the results showed that conventional posterior cervical spine surgery was a risk factor (OR = 6.18, 95% CI (2.43,15.69), P = 0.0001), Fig. 19.
Fig. 19Meta-analysis of conventional posterior cervical spine surgery on axial symptoms after posterior cervical spine surgery
Meta-analysis of the factors of each study was performed using random and fixed two-effects models, respectively, and the combined ORs and 95% CIs of the factors of each study were counted.The results of the fixed- and random-effects models were consistent for most factors, including preoperative neck pain, preoperative C2–7 Cobb angle, facet joint destruction, C2 involvement, operation time, preoperative JOA score, and blood loss, indicating stability in these findings. However, factors such as postoperative cervical range of motion, smoking, mental component summary, C7 spinous process (muscle) destruction, collar wear time, and conventional posterior cervical spine surgery exhibited variability between the two models, suggesting potential heterogeneity.For postoperative cervical range of motion, the composite results for postoperative cervical range of motion tended to stabilise after exclusion of the literature on a case-by-case basis, Table 3.
Table 3Comparison of combined results of models with different effects for each factor(OR/SMD(95%))Research factorsFixed effect modelRandom effect modelSex1.18(0.86,1.60)0.87(0.48,1.58)Age1.51(0.96,2.37)0.17(0.00,41.19)Preoperative neck pain2.22(1.48,3.33)2.25(1.30,3.89)Preoperative C2–7 Cobb angle0.57(0.39,0.82)0.57(0.39,0.82)Smoking1.81(1.04,3.15)1.86(0.93,3.73)Operation time1.01(0.99,1.02)1.01(0.99,1.02)Preoperative JOA score0.74(0.39,1.43)0.74(0.39,1.43)Postoperative JOA−0.10(−0.38,0.18)−0.13(−0.76,0.50)Facet joints destruction2.32(1.59,3.39)2.32(1.59,3.39)Postoperative cervical range of motion0.45(0.32,0.64)0.27(0.07,1.08)C2 involvement3.78(2.04,7.01)3.84(1.89,7.81)C2-7 SVA0.98(0.96,1.01)1.01(0.93,1.10)Mental component summary1.12(1.05,1.19)1.40(0.74,2.67)C7 spinous process(muscule) destruction2.74(1.57,4.78)3.38(1.13,10.08)Collar wear time0.85(0.74,0.98)1.08(0.55,2.12)Blood loss1.02(0.98,1.06)1.02(0.98,1.06)Types of disease0.72(0.40,1.30)0.69(0.27,1.76)Conventional posterior cervical spine surgery6.10(3.66,10.16)6.18(2.43,15.69)
A funnel plot was used to test for publication bias for the most influential factors sex, conventional posterior cervical spine surgery and preoperative neck pain that were included in the literature.The funnel plot of the preoperative neck pain factor showed general symmetry(Egger, t = 0.31, P = 0.779), Fig. 20, the funnel plot of conventional posterior cervical spine surgery also showed general symmetry (Egger, t = 2.83, P = 0.066; Harbord, t=−0.37, P = 0.736), Fig. 21; however, for sex, the funnel plots showed publication bias (Egger, t=−3.22, P = 0.032), Fig. 22. The trim and fill method (Q = 0.940, P = 0.967), with fixed effect model, logor = 0.161, 95% CI(−1.027,1.349), by linear method after 2 iterations, the software estimated the missing studies to be 3. Meta-analysis after inclusion finally showed Q = 0.940, P = 0.967, with fixed effect model, logor = 1.175, 95% CI (0.358,3.855), and a reversal of the combined results, suggesting that it may be related to factors such as the fact that some negative results are not easy to publish. This implies that the observed non-significant association between gender and axial symptoms may be influenced by selective publication. Therefore, we urge caution in interpreting this result and recommend that future studies explicitly report gender-based outcomes, regardless of statistical significance, Fig. 23.
Fig. 20Preoperative neck pain-publication bias funnel plot
Fig. 21Conventional posterior cervical spine-publication bias funnel plot
Fig. 22Sex-publication bias funnel plot Fig. 23Sex-funnel plot after clipping and patching
Axial pain, or axial neck pain, with symptoms including neck pain and stiffness is a common complication after posterior cervical spine surgery [30]. Persistent axial pain may be a main cause of patient dissatisfaction after cervical spine surgery, even in patients with good neurologic recovery [31]. Systematic evaluations have been performed to report risk factors for postoperative axial symptoms, but almost all of them are controversial [6]. Therefore, a Meta-analysis was performed and the pooled results indicated that preoperative neck pain, facet joints destruction, C7 spinous process (muscle) destruction, conventional posterior cervical spine surgery, and C2 involvement were risk factors for the emergence of axial symptoms following surgery on the posterior cervical spine. Increased postoperative cervical range of motion and preoperative C2-C7 Cobb enlargement were protective factors.Gender, age, operation time, JOA score, C2-7 SVA, blood loss, and types of disease were unrelated.
The definition of axial symptoms varied among the included studies, with some employing self-reported questionnaires and others utilizing clinical criteria such as those proposed by Hosono, Gerbershagen, or Yoshida. To address this inconsistency, we adopted a unified operational definition encompassing postoperative neck pain, stiffness, or localized discomfort in the cervical region, explicitly excluding symptoms attributable to radiculopathy or myelopathy.Although assessment methods differed, all studies evaluated symptoms within a comparable clinical framework following posterior cervical spine surgery. Sensitivity analyses were conducted in subgroups with definitional variability, and the direction and significance of pooled estimates remained stable. Therefore, while this heterogeneity in definitions is acknowledged as a potential limitation, its impact on the overall findings appears minimal.
Preoperative neck pain is a risk factor.With the heterogeneity observed throughout the study (I²= 39%, p = 0.16), we still used a random-effects model for the Meta-analysis, which is more appropriate when the study exhibits differences in effect sizes, which may be influenced by factors such as patient population, surgical technique, and outcome indicators. The random-effects model accounted for these differences, resulting in a more reliable overall effect on preoperative neck pain as a risk factor for axial symptoms after posterior cervical spine surgery.It has been found that patients who experienced neck pain before surgery were more likely to express dissatisfaction with their neck pain after surgery, and if these patients underwent immobilisation then some of them had less postoperative neck pain [16]. Yoshida M et al. [23] showed that approximately 40% of the patients exhibited certain axial symptoms post-surgery, yet it mainly took place in in those who had these symptoms before the operation and continued to have these symptoms after the surgery among patients.
Facet joint destruction was identified as a significant risk factor for postoperative axial symptoms. Prior studies have associated articular synovial joints with 40–55% of chronic neck pain [32]. One possible explanation is that intraoperative manipulation may activate nociceptors in the posterior branches of spinal nerves or cause irritation to the joint surface, potentially triggering inflammation and prolonged discomfort [12]. However, these proposed mechanisms remain speculative and require further investigation.The impact of facet joint destruction may vary depending on the surgical approach. In decompression-alone procedures, facet joint injury may contribute to instability, leading to increased axial pain. In contrast, fusion surgery aims to stabilize the affected segments, potentially mitigating the effects of facet joint damage on postoperative pain. Nevertheless, even in fusion procedures, periarticular soft tissue retraction and scarring may still play a role in axial symptoms. Wang et al. [6] suggested that postoperative axial symptoms might be associated with soft tissue retraction, periarticular anatomy disruption, and subsequent necrosis and fibrosis. Similarly, Manchikanti L et al. [33] identified the cervical facet joints as a potential source of chronic neck pain, affecting both postoperative and non-operative patients.Given these findings, further research is needed to clarify the differential impact of decompression versus fusion on facet joint-related axial symptoms. Additionally, to ensure consistency, axial symptoms in this study are defined as postoperative neck pain, stiffness, and discomfort localized to the cervical spine, excluding radiculopathy or myelopathy-related symptoms.
C7 spinous process(muscle) destruction is another risk factor for axial symptoms after posterior cervical spine surgery. It’s possible that the C7 spinous process is vital as a connecting site for the collateral ligament, trapezius, and rhomboid muscles, aiding in maintaining cervical spine stability [12]. Hosono N et al. [26] proposed that the trapezius and rhomboid muscles, linking the C7 spinous process with the scapula, become elongated due to scapular retraction as the upper limb descends, leading to axial neck pain when the C7 spinous process is damaged.
Conventional posterior cervical spine surgery primarily refers to standard laminoplasty and does not include specific muscle preservation techniques; for example, conventional C3-C7 single- or double-portal laminoplasty without preservation of muscle attachment at C2 or C7 [19, 27]. These procedures typically fail to address the deep extensor stops, which may lead to a higher incidence of postoperative axial symptoms.Conventional posterior cervical spine surgery is an important influence on the emergence of axial symptoms following surgery on the posterior cervical spine. Liu Y et al. [19] found that post-modified laminoplasty, the occurrence of axial symptoms was notably less compared to traditional surgical procedures. It has been reported that jump laminectomy can preserve the attachment point of deep extensor muscles and effectively reduce the incidence of postoperative axial symptoms [29]. Takeuchi k et al. [28] demonstrated that preservation of the semispinalis cervicis(SSC) insertion into C2 by C4-C7 laminoplasty and C3 laminectomy can reduce the incidence of axial symptoms, which is consistent with the results of Lin W et al. [27].
C2 involvement is a risk factor for the emergence of axial symptoms following surgery on the posterior cervical spine.The paraspinal muscles on the posterior side of the C2 spinous process, such as the semispinalis muscle, play an important role as a dynamic stabiliser and in the posterior extensor mechanism [22]. C2 involvement may lead to axial symptoms by disrupting the cervical extensor mechanisms, particularly the cervical semispinalis muscles, which play a role in dynamic stabilisation [34], impaired repositioning of these muscles may affect cervical alignment and postoperative discomfort. Nevertheless, this hypothesis has not been fully confirmed.The risk of axial symptoms when laminoplasty involves C2 was found to be 2.959 times higher than when the C2 structure was intact [13]. Wang S J et al. [6] analyzed eight different studies, revealing that altered laminoplasty resulted in reduced axial pain compared to traditional laminoplasty.
Increased postoperative cervical mobility as a protective factor for axial symptoms following surgery on the posterior cervical spine.Ruan C et al. [12] discovered that a notable decrease in cervical movement poses a risk for the emergence of axial symptoms. Disruption of posterior cervical structures, such as the posterior musculature, the collateral ligaments, and other bones, may lead to reduced cervical mobility and concomitant axial symptoms, whereas axial symptoms after cervical spine surgery may limit cervical mobility, complicating the assessment of whether diminished cervical movement is a contributing factor to or a result of post-surgery axial issues [18].
Preoperative C2-7 Cobb angle enlargement is a protective factor for the emergence of axial symptoms following surgery on the posterior cervical spine.Insufficient curvature in the cervical area before surgery frequently results in neck and shoulder discomfort, compensating for the diminished anterior convexity of the cervix, and in order to maintain the mechanical balance in the sagittal plane, the muscles and ligaments will be contracted and fatigued for a long period of time, atrophy and degeneration will occur, and axial symptoms, such as cervical and back pain, will eventually occur [12]. In addition, from a biomechanical point of view, kyphosis exhibits greater bending stress than anterior kyphosis, which can adversely affect the posterior muscles and lead to postoperative axial pain [19]. Therefore, increasing the preoperative C2-7 Cobb angle is a protective factor against the occurrence of axial symptoms following surgery on the posterior cervical spine.
Meta-analysis results showed that gender, age, operation time, preoperative JOA score, C2-7 SVA, blood loss, and types of disease, which are 7 factors, were not associated with the postoperative axial symptoms were not relevant. As for the relationship between smoking, collar wear time and mental component summary factors and the occurrence of axial symptoms following surgery on the posterior cervical spine is debatable.Given the paucity of relevant research literature available, the credibility of the final conclusions drawn may be compromised.For risk factors with limited data, only two studies met the inclusion criteria. While no strict numerical threshold was pre-defined for pooled analysis, we exercised caution when interpreting results based on a small number of studies. For such cases, we presented results from both fixed- and random-effects models to assess consistency and explicitly noted the instability in the findings. In addition, sensitivity analyses were conducted, and where outcomes diverged between models, we refrained from drawing definitive conclusions. These variables were thus discussed as inconclusive and were acknowledged as limitations in our interpretation of risk factors. Nonetheless, the heterogeneity test for each key result was insignificant, indicating a comparatively low level of heterogeneity in the research. The sensitivity analysis with the assessment of publication bias allowed us to confirm the robustness of the results. Therefore, the combined conclusions drawn from our study are relatively plausible.
To reduce the occurrence of postoperative axial symptoms, targeted measures should be implemented based on the identified risk factors. Our analysis suggests that preoperative neck pain, facet joint destruction, C2 involvement, and conventional posterior cervical spine surgery are significant contributors to postoperative axial symptoms. Therefore, preoperative evaluation should focus on identifying and addressing these risk factors.Surgically, minimizing facet joint destruction and preserving C2 structural integrity may help reduce the risk of postoperative axial pain. Additionally, early postoperative rehabilitation, including guided neck muscle exercises, may contribute to improved cervical mobility and symptom relief.While smoking cessation is generally beneficial for surgical outcomes, its direct correlation with axial symptoms remains inconclusive in our analysis. Given the higher risk associated with conventional posterior cervical spine surgery, careful surgical planning and techniques aimed at minimizing tissue disruption are essential for reducing the risk of axial symptoms.
While smoking cessation is generally beneficial for surgical outcomes, its direct correlation with axial symptoms remains inconclusive in our analysis. Therefore, we have refined our recommendations to align more closely with the findings of this study.There are some limitations in this study, which (1) some studies were unable to extract valid data or only did one-way analyses, resulting in a small number of literature included for each influential factor; (2) the posterior cervical spine surgical procedure is not uniform, and the skill level of the surgical operator largely determines the effectiveness of the procedure and may have an impact on the surgical outcome, which may lead to statistical errors; 3) inconsistent definitions for assessing axial symptoms, resulting in some of the indicators not being able to be combined, which reduces the persuasive power of the results; 4) different follow-up times for the assessment of axial symptoms across studies.
Furthermore, compared to prior systematic reviews, such as Wang et al., which provided only qualitative summaries of axial symptoms after posterior cervical spine surgery, our study incorporated a quantitative meta-analysis using data from 19 studies, many of which were published in the last decade. This allowed us to generate pooled effect sizes and assess the statistical strength of associations. In addition, our analysis incorporated sensitivity testing, publication bias assessment, and dual-model validation (fixed- and random-effects), thereby enhancing methodological rigor. We also included variables such as collar wear time, mental component summary, and smoking—factors either overlooked or inconsistently reported in earlier work. These aspects represent important updates that enhance the current understanding of risk and protective factors for postoperative axial symptoms. To our knowledge, this is the most comprehensive and statistically supported meta-analysis on this topic to date.
Preoperative neck pain, smoking, facet joints destruction, C7 spinous process (muscle) destruction, conventional posterior cervical spine surgery and C2 involvement were risk factors for axial symptoms following surgery on the posterior cervical spine, and increased postoperative cervical mobility and preoperative C2-7 Cobb angle enlargement were protective factors for axial symptoms following surgery on the posterior cervical spine, however, gender, age, operation time, preoperative JOA score, C2-7 SVA, mental component summary, collar wear time, blood loss, and types of disease were not associated with postoperative axial symptoms. While smoking and collar wear time were identified as potential risk factors for postoperative axial symptoms, the evidence supporting these factors remains weak due to the limited number of studies available and the inconsistencies in their findings. Specifically, the pooled analysis for smoking and collar wear time included only two studies, and the results showed considerable instability between the fixed- and random-effects models. Therefore, these findings should be interpreted with caution.In view of these limitations, the findings require validation through future large-scale, prospective, multicenter studies.
Supplementary Material 1.
Supplementary Material 2.