Cervical spondylotic myelopathy (CSM) is a progressive, clinical entity characterized by disc degeneration, herniation, and degenerative changes resulting in cervical spinal cord compression, and ultimately, sensorimotor disturbance. Affecting approximately 605 per million adults in North America,1 the condition warrants surgical intervention in well-selected patients to prevent neurological decline, with many patients noting neurological and functional improvement.2
Depending on the extent and location of neural compression, decompressive surgery may be conducted from an anterior approach (e.g., anterior cervical discectomy and fusion [ACDF], corpectomy, or arthroplasty) or posterior approach (e.g., posterior laminectomy alone, posterior laminectomy and fusion [PCLF], or laminoplasty). The optimal strategy is debated,3 and studies have compared both anterior and posterior approaches for CSM, with a randomized controlled trial (RCT) demonstrating no significant difference in physical functioning at the 1-year follow-up.4 Additionally, clinically meaningful improvements in functioning were observed regardless of approach.4
Although classic descriptions of CSM do not include neck pain as a chief symptom, approximately 40%–80% of patients ultimately present with neck pain.5–9 There are multiple possible mechanisms for severe neck pain in patients with cervical degenerative disease, including disc herniation, degenerative disc disease, facet degeneration, spondylosis, listhesis/instability, malalignment, and muscular strain.10–17 In this subset of patients with severe axial neck pain, it is less clear whether an anterior or posterior approach may be most beneficial with regard to neck pain. Proponents for anterior approaches hypothesize that sparing of the posterior cervical musculature may reduce neck pain postoperatively.18,19 As postoperative neck pain is associated with significant disability, dissatisfaction, and poorer quality of life following surgery for cervical myelopathy,20 its careful evaluation after surgery for CSM is of great importance to multiple stakeholders. Supporting this notion, in a survey of 481 patients with cervical myelopathy querying disease recovery priorities, pain recovery was ranked as the top recovery priority.21
Here, we used a large, multicenter cervical myelopathy registry, the Quality Outcomes Database (QOD) CSM module, to compare postoperative neck pain between 3- and 4-level ACDF and PCLF in patients with CSM who presented with severe axial neck pain.
Methods
Selection of Patients
This was a retrospective study of prospectively collected data using the QOD CSM module.22–24 Institutional review board approval (University of California, San Francisco) was obtained, and patient consent was not required. Briefly, the QOD CSM module is a multihospital, 14-site database that utilizes data from patients prospectively enrolled in the cervical QOD registry at each site. The QOD CSM module contains data that is audited by each participating site and a central team and is augmented with additional data points. Inclusion and exclusion criteria for the overall data set have been described previously.23 For the QOD CSM module, we included adult patients (≥ 18 years) with 1) a surgical indication of CSM, 2) a predominant symptom of myelopathy, 3) a modified Japanese Orthopaedic Association scale (mJOA) score < 17, and 4) who underwent elective surgery between January 2016 and December 2018. Patients were excluded if they had a spinal infection, tumor, fracture, traumatic dislocation, deformity, or neurological paralysis due to preexisting spine disease or injury. Here, we studied the patients who had severe neck pain at baseline (defined as a visual analog scale [VAS] pain score of 7 or greater) who underwent a 3- to 4-segment subaxial ACDF or PCLF. Specifically for this study, we excluded patients who did not have severe neck pain (i.e., VAS neck pain score < 7), those who did not undergo subaxial ACDF or PCLF, those who did not undergo 3- to 4-segment fusions, and those who underwent two-stage procedures.
Study Variables and Outcomes
Study variables and outcomes are described in Table 1. Outcomes at 3, 12, and 24 months were collected.
Study variables and outcomes
| Study variables | Demographics: age, sex, race, insurance type, education level, & employment status. Baseline clinical characteristics: BMI, smoking status, ASA grade, type of symptoms (arm weakness, arm pain, arm numbness, neck pain), & location of pain (neck, arm), & comorbidities (diabetes mellitus I/II, coronary artery disease, anxiety, depression, arthritis). Postop parameters: EBL, hospital LOS, readmission w/in 30 & 90 days, reop w/in 30 days, cumulative reoperation w/in 24 mos, return to work & baseline activities. |
| Primary outcomes | Neck pain assessed using the VAS score (range 0 [no pain] to 10 [worst pain possible]). Pain improvement: defined as a binary variable as either achieving any improvement in pain vs worsening or no change in the VAS neck pain score. Pain-free status: defined as achievement of a VAS score of 0 at the specified follow-up time point. MCID in neck pain VAS score: defined as a score change of −2.6 points.25–27 |
| Secondary outcomes | Degree of cervical myelopathy measured using the mJOA score.28 Arm pain: assessed using the VAS score. Disability: determined using NDI (calculated by summing the ratings [ranging from 0 indicating no disability due to pain and 5 indicating the most severe disability due to pain] from 10 sections and converted to a percentage [out of 100%], which determines the degree to which neck pain contributes to a pt’s ability to perform daily activities of living. QOL: assessed using EQ-VAS and EQ-5D. EQ-VAS score: ranges from 0 (worst imaginable health) to 100 (best imaginable health) & reports the pts’ evaluation of their overall health status. The EQ-5D: tool to assess the health-related QOL of pts & is graded on a scale from −0.11 (state equivalent to being dead) to 1 (full health). Pt satisfaction: evaluated using the NASS pt satisfaction index with scores ranging from 1 to 4. A score of 1 indicates “the treatment met my expectations,” 2 indicates “I did not improve as much as I had hoped, but I would undergo the same treatment for the same outcome,” 3 indicates “I did not improve as much as I had hoped, and I would not undergo the same treatment for the same outcome,” and 4 indicates “I am the same or worse than before treatment.” |
ASA = American Society of Anesthesiologists; EBL = estimated blood loss; LOS = length of stay; NASS = North American Spine Society; pt = patient; QOL = quality of life.
Statistical Analysis
Descriptive categorical variables were summarized using frequency counts and continuous variables using means ± SD. Linear regression was used for continuous variables and logistic regression was used for categorical variables. Paired and unpaired t-tests and chi-square tests were used as appropriate. When appropriate, tests of linearity for the target-feature relationship were conducted to confirm that the linearity assumption was met. Multivariable analysis, including covariates reaching p < 0.05 on univariable comparisons between ACDF and PCLF, were used to compare the differences in PROs at the 3-, 12-, and 24-month follow-ups between patients who underwent ACDF and those who underwent PCLF. The PCLF group was used as the reference group for calculations. Missing data were handled with the missForest imputation algorithm, which imputes all missing data using the mean/mode and then fits a random forest model to predict the missing values for each variable by going through an iterative process until a stopping criterion is met. We also conducted sensitivity analyses using propensity matching (1:1 using the nearest-neighbor method) and complete case analysis. All analyses were done using RStudio (RStudio, Inc.).
Results
Demographics and Baseline Characteristics
Overall, 1141 patients were included in the QOD CSM module. Of these, 495 (43.4%) presented with severe neck pain (VAS score 7 or greater). After applying inclusion and exclusion criteria (Fig. 1), 119 patients were included in the present study (65 patients with 3- to 4-level ACDF, and 54 patients with 3- to 4-level PCLF). The demographics and baseline characteristics of the included patients are summarized in Table 2. Both groups demonstrated similar rates of 24-month follow-up (86.2% vs 83.3%, p = 0.85). In terms of demographics, the patients who received ACDF were younger (58.3 ± 10.0 vs 64.0 ± 11.1 years, p = 0.01), were employed or employed and on leave (46.2% vs 24.1%, p = 0.01), and had private insurance (64.6% vs 35.2%, p = 0.001) compared with those who received PCLF. The ACDF cohort had a higher percentage with coronary artery disease (16.9% vs 5.6%, p = 0.047) and arthritis (41.5% vs 24.1%, p = 0.04). In terms of baseline characteristics, a greater number of patients who underwent ACDF presented with arm weakness (36.9% vs 20.4%, p = 0.045), arm pain (61.5% vs 40.7%, p = 0.02), arm numbness (76.9% vs 59.3%, p = 0.04), symptom duration greater than 12 months (49.2% vs 42.6%, p = 0.03), and had higher Neck Disability Index (NDI) scores (52.5 ± 15.9 vs 45.9 ± 16.8, p = 0.03) compared with those who underwent PCLF. Otherwise, the two cohorts demonstrated similar characteristics.
Consort diagram outlining the inclusion and exclusion criteria for selection of final cohort of patients. PCF = posterior cervical laminectomy and fusion. Figure is available in color online only.
Patient characteristics
| ACDF (n = 65) | PCLF (n = 54) | p Value | |
|---|---|---|---|
| 24-mo follow-up, n (%) | 56 (86.2) | 45 (83.3) | 0.85 |
| Age in yrs, mean ± SD | 58.3 ± 10.0 | 64.0 ± 11.1 | 0.01 |
| Female sex, n (%) | 32 (49.2) | 27 (50.0) | 0.93 |
| BMI, mean ± SD | 29.8 ± 6.7 | 30.3 ± 5.6 | 0.68 |
| Smoker, n (%) | 14 (21.5) | 9 (16.7) | 0.61 |
| Comorbidities, n (%) | |||
| Diabetes mellitus | 19 (29.2) | 10 (18.5) | 0.17 |
| Coronary artery disease | 11 (16.9) | 3 (5.6) | 0.047 |
| Anxiety | 13 (20.0) | 16 (29.6) | 0.23 |
| Depression | 15 (23.1) | 19 (35.2) | 0.15 |
| Arthritis | 27 (41.5) | 13 (24.1) | 0.04 |
| Caucasian race, n (%) | 51 (78.5) | 34 (63.0) | 0.07 |
| ≥4 yrs of college-level education, n (%) | 15 (23.1) | 15 (27.8) | 0.39 |
| Employed or employed & on leave, n (%) | 30 (46.2) | 13 (24.1) | 0.01 |
| Insurance | 0.001 | ||
| Medicare | 16 (24.6) | 28 (51.9) | |
| Medicaid | 6 (9.2) | 6 (11.1) | |
| VA/government | 1 (1.5) | 1 (1.9) | |
| Private | 42 (64.6) | 19 (35.2) | |
| Presenting symptoms, n (%) | |||
| Arm weakness | 24 (36.9) | 11 (20.4) | 0.045 |
| Arm pain | 40 (61.5) | 22 (40.7) | 0.02 |
| Arm numbness | 50 (76.9) | 32 (59.3) | 0.04 |
| Neck pain | 53 (81.5) | 38 (70.4) | 0.16 |
| Predominant location of pain | 0.65 | ||
| Neck | 23 (35.4) | 26 (48.1) | |
| Arm | 9 (13.8) | 5 (9.3) | |
| Motor deficit, n (%) | 43 (66.2) | 34 (63.0) | 0.72 |
| Independently ambulatory, n (%) | 57 (87.7) | 41 (75.9) | 0.18 |
| Symptom duration in mos, n (%) | 0.03 | ||
| <12 | 25 (38.5) | 27 (50.0) | |
| >12 | 32 (49.2) | 23 (42.6) | |
| ASA grade, n (%) | 0.28 | ||
| I or II | 26 (40.0) | 27 (50.0) | |
| III or IV | 39 (60.0) | 27 (50.0) | |
| Levels fused, mean ± SD | 3.2 ± 0.4 | 3.5 ± 0.5 | 0.83 |
| Fusions crossing cervicothoracic junction, n (%) | 0 (0) | 3 (5.6) | |
| Baseline mJOA, mean ± SD | 11.8 ± 2.6 | 11.2 ± 3.1 | 0.21 |
| Baseline VAS neck pain, mean ± SD | 8.4 ± 1.2 | 8.2 ± 1.0 | 0.34 |
| Baseline VAS arm pain, mean ± SD | 6.9 ± 2.7 | 6.9 ± 2.7 | 0.99 |
| Baseline NDI, mean ± SD | 52.5 ± 15.9 | 45.9 ± 16.8 | 0.03 |
| Baseline EQ-VAS, mean ± SD | 54.2 ± 19.2 | 53.0 ± 22.7 | 0.77 |
| Baseline EQ-5D, mean ± SD | 0.5 ± 0.2 | 0.5 ± 0.2 | 0.85 |
VA = Veterans Administration.
Boldface type indicates statistical significance.
Perioperative Outcomes and Complications
A comparison of the perioperative outcomes between the two groups is shown in Table 3. Patients who underwent ACDF had lower estimated blood loss (77.3 ± 61.9 vs 168.0 ± 177.0 mL, p = 0.001) and a shorter length of hospital stay (2.0 ± 1.5 vs 4.6 ± 4.6 days, p < 0.001) compared with those who underwent PCLF. Furthermore, a higher proportion of patients in the ACDF group were discharged to home or home healthcare (93.9% vs 64.8%, p < 0.001) compared with those in the PCLF group. There were 2 reoperations within 30 days (2 surgical site infections) for PCLF compared with zero reoperations within 30 days for the ACDF cohort (p = 0.20). There were no differences for reoperations at 24 months (ACDF: 3.1% vs PCLF: 5.6%, p = 0.83).
Perioperative outcomes and complications
| ACDF (n = 65) | PCLF (n = 54) | p Value | |
|---|---|---|---|
| EBL in ml, mean ± SD | 77.3 ± 61.9 | 168.0 ± 177 | 0.001 |
| Hospital LOS in days, mean ± SD | 2.0 ± 1.5 | 4.6 ± 4.6 | <0.001 |
| Discharge disposition, n (%) | <0.001 | ||
| Home routine | 56 (86.2) | 27 (50.0) | |
| Home w/ home healthcare services | 5 (7.7) | 8 (14.8) | |
| Postacute on nonacute care setting | 3 (4.6) | 17 (31.5) | |
| Transferred to another acute care facility | 0 (0) | 2 (3.7) | |
| Readmission w/in 30 days, n (%) | 0 (0) | 1 (1.9) | 0.45 |
| SSI/wound dehiscence | 0 (0) | 1 (1.9) | |
| Readmission w/in 90 days, n (%) | 1 (1.5) | 3 (5.6) | 0.48 |
| SSI/wound dehiscence | 0 (0) | 3 (5.6) | |
| DVT | 1 (1.5) | 0 (0) | |
| Reop w/in 30 days, n (%) | 0 (0) | 2 (3.7) | 0.20 |
| SSI/wound dehiscence | 0 (0) | 2 (3.7) | |
| Cumulative reop w/in 24 mos, n (%) | 2 (3.1) | 3 (5.6) | 0.83 |
| SSI/wound dehiscence | 0 (0) | 2 (3.7) | |
| Hardware failure/pseudarthrosis | 1 (1.5) | 0 (0) | |
| Adjacent-segment degeneration | 1 (1.5) | 1 (1.9) |
DVT = deep vein thrombosis; SSI = surgical site infection.
Boldface type indicates statistical significance.
Univariate Analysis of Postoperative Neck Pain Outcomes at 3, 12, and 24 Months
Postoperative VAS neck pain outcomes at the 3-, 12-, and 24-month follow-ups for patients who underwent ACDF and PCLF are summarized in Table 4. Within each group, both ACDF and PCLF cohorts experienced significant improvements in neck pain at 3 months (ACDF: mean baseline 8.4 ± 1.2 vs 3-month follow-up 4.0 ± 3.0, p < 0.001; PCLF: mean baseline 8.2 ± 1.0 vs 3-month follow-up 3.6 ± 3.0, p < 0.001), 12 months (ACDF: mean baseline 8.4 ± 1.2 vs 12-month follow-up 3.8 ± 3.1, p < 0.001; PCLF: mean baseline 8.2 ± 1.0 vs 12-month follow-up 4.7 ± 3.3, p < 0.001), and 24 months (ACDF: mean baseline 8.4 ± 1.2 vs 24-month follow-up 2.9 ± 2.9, p < 0.001; PCLF: mean baseline 8.2 ± 1.0 vs 24-month follow-up 3.6 ± 3.4, p < 0.001). There was no between-group difference in change in neck pain scores at 3 months (change −4.4 ± 2.7 vs −4.6 ± 2.8, p = 0.75), 12 months (change −4.3 ± 2.7 vs −4.1 ± 3.0, p = 0.68), and 24 months (change −5.5 ± 2.9 vs −4.6 ± 3.5, p = 0.13) (Fig. 2A). ACDF was associated with a higher rate of neck pain improvement (of any magnitude) at 24 months (93.8% vs 81.5%, p = 0.047). Otherwise, both ACDF and PCLF achieved a similar frequency of pain improvement (3 months: 90.8% vs 90.7%; 12 months: 90.8% vs 83.3%), pain-free status (3 months: 18.5% vs 24.1%; 12 months: 9.2% vs 16.7%; 24 months: 29.2% vs 27.8%), and reaching minimal clinically important difference (MCID) (3 months: 73.8% vs 74.1%; 12 months: 75.4% vs 74.1%; 24 months: 81.5% vs 77.8%) (all p > 0.05) at all follow-up time points (Fig. 2B and 2C).
Univariate comparison of clinical outcomes for ACDF versus PCLF at 3, 12, and 24 months
| ACDF (n = 65) | PCLF (n = 54) | Unadjusted p Value* | |
|---|---|---|---|
| 3 mos | |||
| Primary outcomes | |||
| VAS neck pain, mean ± SD | 4.0 ± 3.0 | 3.6 ± 3.0 | 0.52 |
| VAS neck pain change, mean ± SD | −4.4 ± 2.7 | −4.6 ± 2.8 | 0.75 |
| VAS neck pain improvement, n (%) | 59 (90.8) | 49 (90.7) | 0.99 |
| VAS neck pain pain-free, n (%) | 12 (18.5) | 13 (24.1) | 0.46 |
| MCID VAS neck pain, n (%) | 48 (73.8) | 40 (74.1) | 0.98 |
| Secondary outcomes | |||
| VAS arm pain, mean ± SD | 3.1 ± 3.0 | 3.5 ± 3.4 | 0.43 |
| VAS arm pain change, mean ± SD | −3.9 ± 3.5 | −3.4 ± 3.7 | 0.49 |
| mJOA, mean ± SD | 14.0 ± 2.5 | 13.1 ± 2.7 | 0.08 |
| mJOA change, mean ± SD | +2.1 ± 2.7 | +2.0 ± 2.6 | 0.73 |
| NDI, mean ± SD | 27.5 ±17.3 | 28.0 ± 17.9 | 0.88 |
| NDI change, mean ± SD | −25.0 ± 21.3 | −17.9 ± 18.9 | 0.06 |
| EQ-VAS, mean ± SD | 65.4 ± 14.8 | 64.6 ± 23.3 | 0.83 |
| EQ-VAS change, mean ± SD | +11.2 ± 16.0 | +11.6 ± 25.8 | 0.93 |
| EQ-5D, mean ± SD | 0.7 ± 0.2 | 0.7 ± 0.2 | 0.46 |
| EQ-5D change, mean ± SD | +0.2 ± 0.2 | +0.2 ± 0.2 | 0.61 |
| NASS satisfaction, n (%)† | 0.08 | ||
| 1 | 44 (67.7) | 38 (70.4) | |
| 2 | 17 (26.2) | 7 (13.0) | |
| 3 | 3 (4.6) | 5 (9.3) | |
| 4 | 1 (1.5) | 4 (7.4) | |
| Return to work, n (%)‡ | 16 (47.1) | 5 (21.7) | 0.09 |
| Return to baseline activities, n (%)‡ | 27 (50.9) | 10 (21.3) | 0.004 |
| 12 mos | |||
| Primary outcomes | |||
| VAS neck pain, mean ± SD | 3.8 ± 3.1 | 4.7 ± 3.3 | 0.18 |
| VAS neck pain change, mean ± SD | −4.3 ± 2.7 | −4.1 ± 3.0 | 0.68 |
| VAS neck pain improvement, n (%) | 59 (90.8) | 45 (83.3) | 0.24 |
| VAS neck pain pain-free, n (%) | 6 (9.2) | 9 (16.7) | 0.24 |
| MCID VAS neck pain, n (%) | 49 (75.4) | 40 (74.1) | 0.87 |
| Secondary outcomes | |||
| VAS arm pain, mean ± SD | 2.7 ± 2.5 | 3.5 ± 3.0 | 0.13 |
| VAS arm pain change, mean ± SD | −4.2 ± 3.2 | −3.4 ± 3.8 | 0.24 |
| mJOA, mean ± SD | 13.9 ± 2.5 | 13.0 ± 2.7 | 0.06 |
| mJOA change, mean ± SD | +2.1 ± 3.3 | +1.8 ± 3.0 | 0.66 |
| NDI, mean ± SD | 27.5 ± 18.9 | 28.0 ± 19.3 | 0.87 |
| NDI change, mean ± SD | −25.0 ± 21.9 | −17.9 ± 20.0 | 0.07 |
| EQ-VAS, mean ± SD | 66.2 ± 19.8 | 65.8 ± 19.8 | 0.92 |
| EQ-VAS change, mean ± SD | +12.0 ± 24.2 | +12.8 ± 27.7 | 0.87 |
| EQ-5D, mean ± SD | 0.7 ± 0.2 | 0.7 ± 0.2 | 0.58 |
| EQ-5D change, mean ± SD | +0.2 ± 0.2 | +0.2 ± 0.2 | 0.75 |
| NASS satisfaction, n (%)† | 0.13 | ||
| 1 | 45 (69.2) | 38 (70.4) | |
| 2 | 16 (24.6) | 8 (14.8) | |
| 3 | 2 (3.1) | 2 (3.7) | |
| 4 | 2 (3.1) | 6 (11.1) | |
| Return to work, n (%) | 15 (65.2) | 4 (26.7) | 0.06 |
| Return to baseline activities, n (%) | 22 (55.0) | 13 (36.1) | 0.16 |
| 24 mos | |||
| Primary outcomes | |||
| VAS neck pain, mean ± SD | 2.9 ± 2.9 | 3.6 ± 3.4 | 0.21 |
| VAS neck pain change, mean ± SD | −5.5 ± 2.9 | −4.6 ± 3.5 | 0.13 |
| VAS neck pain improvement, n (%) | 61 (93.8) | 44 (81.5) | 0.047 |
| VAS neck pain pain-free, n (%) | 19 (29.2) | 15 (27.8) | 0.86 |
| MCID VAS neck pain, n (%) | 53 (81.5) | 42 (77.8) | 0.62 |
| Secondary outcomes | |||
| VAS arm pain, mean ± SD | 3.0 ± 3.2 | 2.9 ± 3.1 | 0.85 |
| VAS arm pain change, mean ± SD | −4.0 ±3.5 | −4.1 ± 4.1 | 0.88 |
| mJOA, mean ± SD | 13.8 ± 2.4 | 13.0 ± 2.7 | 0.10 |
| mJOA change, mean ± SD | +2.0 ± 3.1 | +1.9 ± 3.8 | 0.83 |
| NDI, mean ± SD | 28.7 ± 21.7 | 25.5 ± 22.6 | 0.44 |
| NDI change, mean ± SD | −23.8 ± 24.9 | −20.4 ± 24.7 | 0.46 |
| EQ-VAS, mean ± SD | 61.1 ± 23.4 | 64.4 ± 25.2 | 0.46 |
| EQ-VAS change, mean ± SD | +7.0 ± 27.5 | +11.4 ± 33.9 | 0.44 |
| EQ-5D, mean ± SD | 0.7 ± 0.2 | 0.6 ± 0.3 | 0.15 |
| EQ-5D change, mean ± SD | +0.2 ± 0.3 | +0.2 ± 0.3 | 0.19 |
| NASS satisfaction, n (%)† | 0.15 | ||
| 1 | 45 (69.2) | 31 (57.4) | |
| 2 | 10 (15.4) | 10 (18.5) | |
| 3 | 3 (4.6) | 4 (7.4) | |
| 4 | 7 (10.8) | 9 (16.7) | |
| Return to work, n (%) | 10 (37.0) | 6 (22.2) | 0.46 |
| Return to baseline activities, n (%) | 7 (70.0) | 4 (36.4) | <0.001 |
Boldface type indicates statistical significance.
Represents between-group comparisons between ACDF and PCLF.
Comparing NASS 1 and 2 versus 3 and 4.
Percentages do not add to 100% because some data are missing.
Comparison of neck pain outcomes between the two cohorts. A: Box plot of VAS neck pain score distribution at baseline and 3, 12, and 24 months. B–D: Bar graphs of improvement in VAS neck pain, pain-free status, and MCID attainment at 3 (B), 12 (C), and 24 (D) months.
Univariate Analysis of Secondary Outcomes at 3, 12, and 24 Months
The differences in patient-reported outcomes (PROs) and satisfaction between the two groups are noted in Table 4. Patients in both surgical cohorts experienced mean improvement in VAS arm pain, NDI, mJOA, EQ-VAS, and EQ-5D scores at all follow-up time points. There were no significant differences observed between the two cohorts in all PROs. ACDF was associated with a higher rate of return to baseline activities at 3 months (50.9% vs 21.3%, p = 0.004) and 24 months (70.0% vs 36.4%, p < 0.001).
Multivariable Analysis of Postoperative Neck Pain Outcomes at 3, 12, and 24 Months
After accounting for covariates reaching p < 0.05 on univariable comparisons (specifically, age, insurance, coronary artery disease, arthritis, symptoms, employment status, symptom duration, and baseline NDI score), the two cohorts demonstrated similar neck pain and change in neck pain scores at 3, 12, and 24 months (3 months: β = 0.3 [95% CI −0.9 to 1.4], adjusted p = 0.65; 12 months: β = −0.2 [95% CI −1.3 to 0.9], adjusted p = 0.72; 24 months: β = −0.9 [95% CI −2.3 to 0.4], adjusted p = 0.16) (Table 5). As with the univariable analyses, both groups were similarly likely to experience pain improvement, pain-free status, and to reach MCID at 3, 12, and 24 months (all adjusted p > 0.05). We additionally conducted a propensity score–matching analysis comparing neck pain outcomes at the 3-, 12-, and 24-month follow-ups, which confirmed the multivariable analysis results described above (Supplementary Data 1 and 2).
Multivariable comparison of clinical outcomes at 3, 12, and 24 months with PCLF as the reference
| β* | 95% CI | Adjusted p Value | |
|---|---|---|---|
| 3 mos | |||
| Primary outcomes | |||
| VAS neck pain | 0.3 | −0.9 to 1.4 | 0.65 |
| VAS neck pain change | 0.3 | −0.9 to 1.4 | 0.65 |
| VAS neck pain improvement | OR 1.0 | 0.9 to 1.1 | 0.98 |
| VAS neck pain pain-free | OR 1.0 | 0.8 to 1.2 | 0.74 |
| MCID VAS neck pain | OR 1.0 | 0.9 to 1.2 | 0.84 |
| Secondary outcomes | |||
| VAS arm pain | −0.6 | −2.0 to 0.8 | 0.39 |
| VAS arm pain change | −0.05 | −1.6 to 1.5 | 0.95 |
| mJOA | 0.9 | −0.2 to 2.1 | 0.12 |
| mJOA change | −0.03 | −1.2 to 1.1 | 0.95 |
| NDI | −4.5 | −11.4 to 2.4 | 0.20 |
| NDI change | −4.5 | −11.4 to 2.4 | 0.20 |
| EQ-VAS | −2.2 | −10.4 to 6.0 | 0.59 |
| EQ-VAS change | −3.1 | −12.1 to 5.8 | 0.49 |
| EQ-5D | 0.03 | −0.05 to 0.1 | 0.41 |
| EQ-5D change | 0.007 | −0.08 to 0.1 | 0.87 |
| NASS† | OR 1.1 | 0.96 to 1.2 | 0.19 |
| Return to work | OR 1.1 | 0.9 to 1.2 | 0.29 |
| Return to baseline activities | OR 1.4 | 1.2 to 1.6 | <0.001 |
| 12 mos | |||
| Primary outcomes | |||
| VAS neck pain | −0.2 | −1.3 to 0.9 | 0.72 |
| VAS neck pain change | −0.2 | −1.3 to 0.9 | 0.72 |
| VAS neck pain improvement | OR 1.0 | 0.9 to 1.2 | 0.76 |
| VAS neck pain pain-free | OR 1.0 | 0.9 to 1.2 | 0.57 |
| MCID VAS neck pain | OR 1.1 | 0.9 to 1.4 | 0.30 |
| Secondary outcomes | |||
| VAS arm pain | −1.0 | −2.1 to 0.1 | 0.08 |
| VAS arm pain change | −0.4 | −1.8 to 0.9 | 0.52 |
| mJOA | 1.1 | −0.004 to 2.2 | 0.051 |
| mJOA change | 0.1 | −1.2 to 1.5 | 0.83 |
| NDI | −4.5 | −11.9 to 2.8 | 0.22 |
| NDI change | −4.5 | −11.9 to 2.8 | 0.22 |
| EQ-VAS | −0.5 | −8.9 to 7.9 | 0.91 |
| EQ-VAS change | −1.4 | −12.6 to 9.8 | 0.80 |
| EQ-5D | 0.02 | −0.05 to 0.09 | 0.53 |
| EQ-5D change | −0.003 | −0.09 to 0.08 | 0.95 |
| NASS† | OR 1.1 | 0.97 to 1.3 | 0.12 |
| Return to work | OR 1.1 | 0.96 to 1.3 | 0.15 |
| Return to baseline activities | OR 1.2 | 0.99 to 1.4 | 0.06 |
| 24 mos | |||
| Primary outcomes | |||
| VAS neck pain | −0.9 | −2.3 to 0.4 | 0.16 |
| VAS neck pain change | −0.9 | −2.3 to 0.4 | 0.16 |
| VAS neck pain improvement | OR 1.1 | 0.99 to 1.3 | 0.07 |
| VAS neck pain pain-free | OR 1.0 | 0.9 to 1.3 | 0.66 |
| MCID VAS neck pain | OR 1.1 | 0.9 to 1.3 | 0.56 |
| Secondary outcomes | |||
| VAS arm pain | −0.1 | −1.4 to 1.3 | 0.91 |
| VAS arm pain change | 0.5 | −1.1 to 2.1 | 0.55 |
| mJOA | 1.5 | 0.5 to 2.6 | 0.01 |
| mJOA change | 0.6 | −0.9 to 2.1 | 0.42 |
| NDI | −1.2 | −10.1 to 7.7 | 0.79 |
| NDI change | −1.2 | −10.1 to 7.7 | 0.79 |
| EQ-VAS | −6.1 | −16.0 to 3.9 | 0.23 |
| EQ-VAS change | −7.0 | −19.7 to 5.7 | 0.27 |
| EQ-5D | 0.1 | 0.01 to 0.2 | 0.04 |
| EQ-5D change | 0.09 | −0.02 to 0.2 | 0.12 |
| NASS† | OR 1.1 | 0.9 to 1.3 | 0.21 |
| Return to work | OR 1.0 | 0.8 to 1.2 | 0.67 |
| Return to baseline activities | OR 1.2 | 1.1 to 1.4 | 0.002 |
Boldface type indicates statistical significance. β coefficients and 95% CI are presented for ACDF, with PCLF as the reference group, for multivariable analyses. β represents the average degree of change in the outcome variable when ACDF is conducted, compared to PCLF. If the β coefficient is positive, then ACDF has a higher value for that outcome variable than PCLF.
Unless stated otherwise.
Comparison was made between scores 1 and 2 versus scores 3 and 4. OR < 1 for the NASS multivariable analyses indicates higher (more) satisfaction for ACDF, compared with PCLF.
Multivariable Analysis of Secondary Outcomes at 3, 12, and 24 Months
Patients who received ACDF were found to have a higher 24-month mJOA score (β = 1.5 [95% CI 0.5–2.6], adjusted p = 0.01) and 24-month EQ-5D score (β = 0.1 [95% CI 0.01–0.2, adjusted p = 0.04) compared with those who received PCLF (Table 5). Also, patients in the ACDF cohort were more likely to return to baseline activities at 3 and 24 months (3 months: OR = 1.4 [95% CI 1.2–1.6], adjusted p < 0.001; 24 months: OR 1.2 [95% CI 1.1–1.4], adjusted p = 0.002) compared with those in the PCLF cohort. There were no significant differences observed for all other outcomes (adjusted p > 0.05).
Subgroup Analysis of Cases Above the Cervicothoracic Junction: C3–6 or C3–7 ACDF Versus C3–6 or C3–7 PCLF
We repeated the analysis excluding the 3 patients with fusions that included a lower instrumented vertebra in the upper thoracic spine (all PCLF). We compared patients who underwent 3- to 4- level ACDF above the cervicothoracic junction (n = 65) with those who underwent 3- to 4- level PCLF above the cervicothoracic junction (n = 51) (Table 6). The multivariable adjusted analyses for 3- and 12-month neck pain outcomes reflect those observed for all-inclusive cases shown in Table 5. However, at 24 months, patients who underwent ACDF experienced less neck pain (β = −1.8 [95% CI −3.2 to −0.3], adjusted p = 0.02) and greater neck pain change (β = −1.8 [95% CI −3.2 to −0.3], adjusted p = 0.02) and were more likely to report neck pain improvement (OR 1.2 [95% CI 1.0–1.4], adjusted p = 0.03).
Subgroup multivariable comparison of clinical outcomes for 3- to 4-level surgeries not crossing the cervicothoracic junction at 3, 12, and 24 months with PCLF as the reference
| β* | 95% CI | Adjusted p Value | |
|---|---|---|---|
| 3 mos | |||
| Primary outcomes | |||
| VAS neck pain | 0.2 | −1.1 to 1.5 | 0.29 |
| VAS neck pain change | 0.2 | −1.1 to 1.5 | 0.29 |
| VAS neck pain improvement | OR 1.0 | 0.9 to 1.2 | 0.68 |
| VAS neck pain pain-free | OR 1.0 | 0.8 to 1.2 | 0.79 |
| MCID VAS neck pain | OR 1.0 | 0.8 to 1.3 | 0.74 |
| Secondary outcomes | |||
| VAS arm pain | −0.7 | −2.2 to 0.8 | 0.36 |
| VAS arm pain change | −0.9 | −2.6 to 0.8 | 0.30 |
| mJOA | 1.1 | −0.1 to 2.4 | 0.08 |
| mJOA change | 0.3 | −1.0 to 1.5 | 0.69 |
| NDI | −5.3 | −12.5 to 2.0 | 0.15 |
| NDI change | −5.3 | −12.5 to 2.0 | 0.15 |
| EQ-VAS | −1.7 | −10.8 to 7.3 | 0.70 |
| EQ-VAS change | −1.0 | −10.9 to 8.8 | 0.84 |
| EQ-5D | 0.07 | −0.02 to 0.2 | 0.12 |
| EQ-5D change | 0.04 | −0.06 to 0.1 | 0.43 |
| NASS† | OR 1.1 | 0.95 to 1.2 | 0.22 |
| Return to work | OR 1.1 | 0.9 to 1.2 | 0.47 |
| Return to baseline activities | OR 1.4 | 1.1 to 1.6 | 0.001 |
| 12 mos | |||
| Primary outcomes | |||
| VAS neck pain | −0.3 | −1.6 to 0.9 | 0.61 |
| VAS neck pain change | −0.3 | −1.6 to 0.9 | 0.61 |
| VAS neck pain improvement | OR 1.1 | 0.9 to 1.2 | 0.48 |
| VAS neck pain pain-free | OR 1.0 | 0.9 to 1.2 | 0.91 |
| MCID VAS neck pain | OR 1.0 | 0.9 to 1.3 | 0.68 |
| Secondary outcomes | |||
| VAS arm pain | −0.9 | −2.2 to 0.4 | 0.16 |
| VAS arm pain change | −1.1 | −2.7 to 0.5 | 0.16 |
| mJOA | 1.1 | −0.1 to 2.3 | 0.08 |
| mJOA change | 0.2 | −1.3 to 1.7 | 0.78 |
| NDI | −6.7 | −14.8 to 1.4 | 0.10 |
| NDI change | −6.7 | −14.8 to 1.4 | 0.10 |
| EQ-VAS | 1.4 | −7.6 to 10.4 | 0.31 |
| EQ-VAS change | 2.1 | −9.7 to 13.9 | 0.72 |
| EQ-5D | 0.05 | −0.03 to 0.1 | 0.22 |
| EQ-5D change | 0.02 | −0.08 to 0.1 | 0.43 |
| NASS† | OR 1.1 | 0.96 to 1.2 | 0.18 |
| Return to work | OR 1.2 | 1.002 to 1.4 | 0.047 |
| Return to baseline activities | OR 1.2 | 1.01 to 1.5 | 0.04 |
| 24 mos | |||
| Primary outcomes | |||
| VAS neck pain | −1.8 | −3.2 to −0.3 | 0.02 |
| VAS neck pain change | −1.8 | −3.2 to −0.3 | 0.02 |
| VAS neck pain improvement | OR 1.2 | 1.0 to 1.4 | 0.03 |
| VAS neck pain pain-free | OR 1.1 | 0.9 to 1.4 | 0.22 |
| MCID VAS neck pain | OR 1.2 | 0.99 to 1.4 | 0.07 |
| Secondary outcomes | |||
| VAS arm pain | 0.004 | −1.5 to 1.5 | 0.99 |
| VAS arm pain change | −0.2 | −1.9 to 1.5 | 0.82 |
| mJOA | 1.4 | 0.2 to 2.6 | 0.02 |
| mJOA change | 0.6 | −1.0 to 2.2 | 0.48 |
| NDI | −4.5 | −14.2 to 5.1 | 0.35 |
| NDI change | −4.5 | −14.2 to 5.1 | 0.35 |
| EQ-VAS | −3.2 | −14.1 to 7.7 | 0.56 |
| EQ-VAS change | −2.5 | −16.0 to 11.0 | 0.72 |
| EQ-5D | 0.1 | 0.02 to 0.3 | 0.03 |
| EQ-5D change | 0.1 | −0.01 to 0.3 | 0.08 |
| NASS† | OR 1.1 | 0.9 to 1.3 | 0.34 |
| Return to work | OR 0.9 | 0.7 to 1.1 | 0.30 |
| Return to baseline activities | OR 1.2 | 1.1 to 1.4 | 0.004 |
Boldface type indicates statistical significance. β coefficients and 95% CI are presented for ACDF, with PCLF as the reference group, for multivariable analyses. β represents the average degree of change in the outcome variable when ACDF is conducted, compared to PCLF. If the β coefficient is positive, then ACDF has a higher value for that outcome variable than PCLF.
Unless stated otherwise.
Comparison was made between scores 1 and 2 versus scores 3 and 4. OR < 1 for the NASS multivariable analyses indicates higher (more) satisfaction for ACDF, compared with PCLF.
For secondary outcomes, ACDF was associated with a higher 24-month mJOA score (β = 1.4 [95% CI 0.2–2.6], adjusted p = 0.02) and EQ-5D score (β = 0.1 [95% CI 0.02–0.3], adjusted p = 0.03). ACDF was also associated with higher odds of 12-month return to work (OR 1.2 [95% CI 1.002–1.4], adjusted p = 0.047) and 3-, 12-, and 24-month return to baseline activities (3 months: OR 1.4, [95% CI 1.1–1.6], adjusted p = 0.001); 12 months: OR 1.2 [95% CI 1.01–1.5], adjusted p = 0.04); and 24 months: OR 1.2 [95% CI 1.1–1.4], adjusted p = 0.004).
Discussion
Herein, we compared the 3-, 12-, and 24-month postoperative neck pain outcomes for patients with CSM presenting with severe axial neck pain and who underwent 3- or 4-level ACDF or PCLF. In multivariable adjusted analyses, we observed no association between approach and postoperative neck pain. Moreover, both ACDF and PCLF were associated with similar magnitudes of neck pain improvement postoperatively.
High-quality studies comparing anterior and posterior approaches for CSM are limited. The only RCT on the matter—comparing 63 patients undergoing ventral surgery (ACDF) and 100 patients undergoing dorsal surgery (fusion or laminoplasty) for CSM—revealed no association between approach and 1-year change in SF-36 Physical Component Summary score (primary outcome).4 Furthermore, in a secondary analysis comparing ACDF and PCLF specifically (excluding laminoplasty), the study found no association between ACDF and 1- and 2-year changes in the SF-36 Physical Component Summary score from baseline. However, this study did not focus on patients who presented with severe neck pain and did not include a neck pain score as an outcome measure. The present study addressed this knowledge gap by tracking neck pain outcomes following surgery for CSM in a selected population with severe neck pain. Contrary to the hypothesis that sparing of the posterior musculoligamentous structures may afford superior neck pain outcomes for ACDF (compared with PCLF), we did not observe an association between anterior approach and better short- and long-term postoperative neck pain in a population with severe neck pain. Within the limitations of a nonrandomized study, our results suggest that surgeons may select an anterior or posterior approach for 3- or 4-level CSM pathology—in patients reporting severe neck pain—without neck pain itself as a chief consideration. Rather, other clinical and radiographic characteristics may preferentially guide approach selection in CSM with severe neck pain.
Although not typically considered a cardinal symptom of cervical myelopathy, severe neck pain remains common in those who undergo surgery. In our multicenter United States registry, 43.4% of patients who underwent surgery for CSM presented with severe neck pain (VAS score > 6). This is higher than the rate reported in a prior prospective study of 60 patients with CSM, which found that 56.9% of patients complained of no neck pain (defined as 0 to 4 mm out of 100 mm on the 100-mm VAS).9 The authors suggested that their lower rate of neck pain may reflect cultural differences among their non-Western population (the study was conducted in India). In another study conducted in the United States in 1966 by Crandall and Batzdorf,5 the authors described the clinical presentations of 62 patients with CSM and found that 41.9% presented with neck pain. On the other hand, a study of 108 patients with CSM who underwent anterior decompression and arthrodesis reported that 85 patients (78.7%) presented with neck pain.6 Another two studies of patients with CSM found that 81% presented with neck pain.7,8 Certainly, neck pain is a prevalent problem for patients presenting with CSM.
Reassuringly, regardless of surgical approach, a majority of patients noted improvement in neck pain following surgery (93.8% and 81.5% of those receiving ACDF and PCLF, respectively, at the 24-month follow-up). These rates are higher than that reported in a retrospective study of 91 patients undergoing 3- or 4-level ACDF for degenerative disease in a non–neck pain specific population, in which De la Garza-Ramos et al.29 found that 51.4% of patients noted improvement in neck pain. We also observed similar rates of patients undergoing ACDF (81.5%) and PCLF (77.8%) who reported clinically meaningful improvements in neck pain. Our rates of clinically relevant improvement in neck pain are higher than that reported in a prospective study of 258 patients undergoing 1- to 3-level ACDF for cervical disc degeneration, in which 54.7% of patients noted an improvement in VAS neck pain by 2 or more points at the 6-month follow-up.46 Similarly, our PCLF rate of clinically meaningful improvement is higher than a study of 13,179 patients undergoing elective surgery for degenerative cervical disease that reported a 46.6% rate of a 2.6-point reduction in Numeric Rating Scale neck pain postoperatively.47 Our higher rates of improvement reflect that our population is selected for severe neck pain and, as such, has a greater capacity for postoperative improvement.
Still, our data caution that elimination of neck pain might not be a realistic surgical goal for many CSM patients who present with severe neck pain at baseline. Only 27.8% of patients in the PCLF group and 29.2% in the ACDF group reported neck pain freedom at 24 months. These insights into the prevalence and prognosis of CSM patients with severe neck pain may be helpful for surgeons and patients to consider preoperatively.
There are several contributions to postoperative neck pain, some of which are approach dependent. After posterior approaches, neck pain within the first several weeks is partially due to surgical trauma of the posterior cervical musculature30 or nerve root irritation. Thereafter, neck pain is multifactorial and can include postoperative muscular atrophy and musculoligamentous insult/detachment (during posterior approaches) and adjacent disc/facet degeneration, pseudarthrosis, malalignment, instability, and malpositioned hardware (during anterior or posterior approaches). Given our study’s observation that surgical approach is not associated with neck pain outcomes at 3, 12, and 24 months, we may speculate that trauma to posterior cervical musculature and musculoligamentous insult and detachment during posterior approaches might not contribute to neck pain in a clinically impactful manner—outside of the immediate perioperative period—in patients receiving posterior, multilevel operations for CSM with severe neck pain.
Of note, in a subgroup analysis of surgeries excluding the 3 patients with constructs crossing the cervicothoracic junction, we observed less neck pain, superior neck pain change, and higher odds of neck pain improvement for ACDF 24 months postoperatively (but not at 3 and 12 months). Opponents of stopping posterior cervical fusions short of the cervicothoracic junction are concerned that these constructs may precipitate adjacent-segment breakdown and worsen neck pain. Consistent with this, our results indicate that the excluded PCLF cases (which crossed the cervicothoracic junction) tended toward less postoperative neck pain at long-term follow-up. However, multiple studies31–34 have failed to link crossing the cervicothoracic junction after PCLF and postoperative neck pain. Further assessment of the impact of crossing the cervicothoracic junction on patients with severe neck pain—with a larger sample size of patients undergoing PCLF than available herein—is warranted.
For our secondary analyses, we observed a modest association between ACDF and superior mJOA and EQ-5D scores and return to baseline activities. Our finding regarding the mJOA score stands in contrast to a prior prospective, observational report by Ghogawala et al. comparing 28 and 22 patients with CSM (with and without neck pain) undergoing ventral and dorsal fusion, respectively.35 In that study, there was no association observed between approach and mJOA score after adjustment for baseline differences in mJOA score (those undergoing ventral procedures had higher mJOA scores at baseline). Moreover, an RCT by Ghogawala et al.4 revealed no association between ventral and dorsal approaches (including laminoplasty) and EQ-5D and mJOA scores (secondary outcomes). In a retrospective comparison of 26 patients who underwent 4-level ACDF (using stand-alone cages) and 32 patients undergoing 4-level PCLF, Wang et al. found no association between approach and 24-month JOA scores.36 Nonetheless, the occasional association observed between ACDF and superior outcomes in the present study and prior literature suggests that it might be worthwhile to focus on these other outcomes (e.g., EQ-5D and mJOA scores) as a primary outcome measure in a future comparative effectiveness study.
Of note, it is important to consider the impact of socioeconomic status (SES) on the measured postoperative PROs. In a study of operative patients with CSM, Rethorn et al. investigated the relationship between social risk factors and achievement of MCID of 30% from baseline for disability, neck and arm pain, quality of life, and patient satisfaction.37 The authors categorized two comparison groups: 1) a high-risk group defined as non-White race and ethnicity, less frequently college educated, not employed/working, with nonprivate insurance, and of a predominantly lower SES; and 2) a low-risk group defined as White, more frequently college educated, employed, with private insurance, and of a higher SES. They found that the high-risk group had decreased odds of achieving MCID in the measured PROs for both 3- and 12-month follow-ups. In our comparison groups in the current study, we found that there was no statistically significant difference in the SES index between the two groups (p > 0.05, data not shown). However, we did observe differences in other sociodemographic features (i.e., employment status and insurance) and accounted for these differences by treating these as covariates in our multivariable analysis. Furthermore, patients who underwent ACDF tended to be younger than those who underwent PCLF in our study, which could have contributed to more favorable long-term outcomes in mJOA and EQ-5D scores and return to baseline activities.38–40
In our study, we found a similar 24-month rate of reoperation for ACDF (3.1%) and PCLF (5.6%). In the RCT by Ghogawala et al.,4 a similar cumulative reoperation rate (4%–6% within 2 years) was observed as well, with no differences between anterior and posterior approaches (with the posterior cohort including laminoplasty). Complication rates differ between approaches and may be considered in future investigations as well. In the RCT by Ghogawala et al.,4 ventral surgery was associated with a higher risk of complication occurrence (47.6% vs 24.0%), including for minor complications (27.0% vs 7.0%), dysphagia (41% vs 0%), new neurological deficit (9% vs 2%), reoperations (6% vs 4%), and 30-day readmissions (7% vs 0%). Complication profiles differed as well. Dysphagia and hoarseness are observed following ACDF, whereas infection and higher intraoperative blood loss more commonly occur following PCLF.36 Rates of pseudarthrosis may be higher after 3- to 4-level ACDF compared with 3- to 4-level PCLF.36 Subsidence, by definition, can occur only after ACDF. The extent to which these approach-specific complications impact a specific patient (e.g., hoarseness in an opera singer) may also help guide approach selection.
Limitations
This investigation represents a retrospective analysis of a prospectively maintained multicenter data set and holds the inherent limitations of such a study. As a nonrandomized comparison of two surgical techniques, the results are susceptible to selection bias and floor and ceiling effects. However, we attempted to adjust for these with multivariable and propensity matched analyses. Other limitations warrant specific discussion. First, as a registry-based data set, participating surgeons selected the approach they felt most appropriate for CSM with 3- or 4-segment degenerative pathology, so our results might be influenced by other factors driving the nonrandomized selection of either an anterior or posterior approach. However, by including only 3- or 4-segment pathology and excluding other approaches such as corpectomy and laminoplasty, we attempted to create a more homogeneous population (toward clinical equipoise). As such, our findings may not be generalizable to CSM from causes other than 3- or 4-level pathology. Nonetheless, we conducted multivariable adjusted analyses to adjust for baseline differences between the cohorts (e.g., age). Second, our data set—although containing more granularity than many healthcare data sets—does not contain cervical radiographic parameters, fusion data, information on cervical muscle morphology, and specific etiologies of cervical myelopathy (e.g., multilevel disc degeneration/herniation, ossification of the posterior longitudinal ligament, ossification of the yellow ligament, and Klippel-Feil), which may influence whether an anterior or posterior approach may have been selected. Additionally, our registry does not contain information on postoperative dysphagia or recurrent laryngeal nerve injury. Future comparative studies may incorporate these factors. Third, although to our knowledge, this is the largest operative CSM registry cohort; the comparison groups in the present study were only a subset after applying exclusion criteria. Due to differences in power, smaller and larger investigations may arrive at different conclusions. Fourth, our cohort had a mean baseline mJOA score < 12, suggesting severe disease. Severe myelopathy has been shown to lead to a longer path to functional recovery41 but also a greater capacity for overall improvement following surgery for CSM.42–45 Although we adjusted for mJOA score in our final multivariable models, our results should be interpreted considering the baseline severity of disease in our cohort. Additionally, our study does not include a cost analysis and granularity with respect to complication variables. Given that ventral and dorsal surgery may be associated with different costs and complications,4,35 these additional considerations may be factored into future investigations as well. Lastly, as a registry analysis, our results might be influenced by missing data. We mitigated this by using a random forest imputation for the missing data. It is important to note that in our sensitivity analysis (using complete case analysis, Supplementary Data 3), multilevel ACDF was associated with less 24-month VAS neck pain. This suggests that without the utilized imputation, missing data would bias the results to favor multilevel ACDF.
Conclusions
Although not classically considered a presenting symptom of CSM, severe neck pain affects more than 40% of patients who undergo surgery for CSM. In a comparison of 3- or 4-level ACDF and 3- or 4-level PCLF in patients with CSM and severe neck pain, there was no evidence supporting either ACDF or PCLF with regard to postoperative neck pain. Therefore, we may speculate that trauma to posterior cervical musculature and musculoligamentous insult and detachment during posterior approaches may not contribute significantly to long-term postoperative neck pain in patients receiving posterior, multilevel operations for CSM with severe neck pain. In an analysis of secondary outcomes, ACDF was associated with a higher likelihood of returning to baseline activities and superior functional status and quality of life in multivariable adjusted analyses.
Acknowledgments
This research was supported by the NeuroPoint Alliance (NPA), the Neurosurgery Research & Education Foundation (NREF), and the Spine Section. The NPA is a 501(c)(6) affiliate nonprofit organization of the American Association of Neurological Surgeons (AANS) dedicated to the improvement of the quality of care in neurosurgical practice via the institution of national quality registries, such as the one utilized for this study. The NREF is the philanthropic arm of the AANS and has financially supported the creation and maintenance of the QOD. The Spine Section is a neurosurgical community formed in collaboration between the AANS and the Congress of Neurological Surgeons to advance spine and peripheral nerve patient care through education, research, and advocacy.
Disclosures
Dr. CI Shaffrey: direct stock ownership in NuVasive; consultant for NuVasive, Medtronic, and SI Bone; royalties from NuVasive, Medtronic, and Zimmer Biomet; and patent holder for NuVasive, Medtronic, and Zimmer Biomet. Dr. Gottfried: personal fees from RTI pioneer and Medtronic. Dr. Than: consultant for Bioventus, DePuy Synthes, Accelus, and Cerapedics; and honoraria from SI-Bone. Dr. Bisson: consultant for MiRus, Stryker, and Medtronic; and stock ownership in MiRus and nView. Dr. Coric: a consultant for Globus Medical, Medtronic, Spine Wave, Integrity Implants, and NuVasive; stock ownership in Spine Wave and Premia Spine; and royalties from RTI Surgical, Stryker Spine, Spine Wave, Medtronic, and Globus Medical. Dr. Potts: royalties from and consultant for Medtronic. Dr. Foley: consultant for Medtronic; stock ownership in Accelus, Companion Spine, DiscGenics, DuraStat, Medtronic, NuVasive, Practical Navigation, RevBio, Spine Wave, Tissue Differentiation Intelligence, Triad Life Sciences, True Digital Surgery, and Vori; patent holder with Discgenics, Medtronic, and NuVasive; and royalties from Medtronic. Dr. Wang: consultant for DePuy Synthes, Spineology, Medtronic, Globus, and Stryker; patent holder with DePuy Synthes; direct stock ownership in ISD, Kinesiometrics, and Medical Device Partners; royalties from DePuy-Synthes Spine, Children’s Hospital of Los Angeles, Springer Publishing, and Quality Medical Publishing; grants from the Department of Defense; personal fees from DePuy-Synthes Spine, Stryker Spine, K2M, and Spineology; advisory board member for Vallum; and stock ownership in Spinicity and Innovative Surgical Devices. Dr. Fu: consultant for Johnson & Johnson. Dr. Virk: a consultant for DePuy Synthes, Brainlab, and OnPoint Surgical; and stock ownership in OnPoint Surgical. Dr. Knightly: chair of the board of directors of NPA. Dr. Meyer: consultant for Globus and Stryker. Dr. P Park: consultant for Globus, NuVasive, DePuy Synthes, and Accelus; royalties from Globus; and support of non–study-related clinical or research effort from DePuy Synthes, ISSG, SI Bone, and Cerapedics. Dr. Buchholz: consultant for Medtronic and Alphatec. Dr. Tumialan: consultant for Medtronic and Zimmer Biomet; and royalties from Globus Medical. Dr. Turner: consultant for NuVasive, SeaSpine, and ATEC; royalties from NuVasive and SeaSpine; and non–study-related clinical or research support from NuVasive and SeaSpine. Dr. Agarwal royalties from Thieme Medical Publishers and Springer International Publishing. Dr. Chou: consultant for Globus and Orthofix; and royalties from Globus. Dr. Haid: consultant for NuVasive; royalties from Globus Medical, Medtronic, and NuVasive; and owns stock in Globus Medical, NuVasive, and Remedy Health Media. Dr. Mummaneni: consultant for DePuy Synthes, Globus, and Stryker; owns stock in Spinicity/ISD; receives clinical or research support for the study described from NREF; non–study-related clinical or research support from AOSpine and ISSG; and royalties from DePuy Synthes, Thieme Publishers, and Springer Publishers.
Author Contributions
Conception and design: Chan, CI Shaffrey, Gottfried, Than, Bisson, Bydon, Asher, Coric, Potts, Foley, Wang, Fu, Virk, Knightly, Meyer, P Park, Upadhyaya, ME Shaffrey, Buchholz, Tumialán, Turner, Chou, Haid, Mummaneni. Acquisition of data: Chan, CI Shaffrey, Gottfried, C Park, Bisson, Bydon, Coric, Potts, Foley, Wang, Fu, Virk, Knightly, Meyer, P Park, Upadhyaya, ME Shaffrey, Buchholz, Tumialán, Turner, Michalopoulos, Sherrod, Chou, Mummaneni. Analysis and interpretation of data: Chan, Gottfried, C Park, Than, Bisson, Bydon, Asher, Chou, Mummaneni. Drafting the article: Chan, CI Shaffrey, Gottfried, C Park, Bisson, Bydon, Mummaneni. Critically revising the article: Chan, C Park, Than, Bisson, Bydon, Asher, Michalopoulos, Agarwal, Chou, Mummaneni. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Chan. Statistical analysis: Chan, C Park, Mummaneni. Administrative/technical/material support: CI Shaffrey, Gottfried, Bisson, Asher, Knightly, Haid, Mummaneni. Study supervision: CI Shaffrey, Bisson, Mummaneni.
Supplemental Information
Online-Only Content
Supplemental material is available with the online version of the article.
Supplementary Data 1–3. https://thejns.org/doi/suppl/10.3171/2022.6.SPINE22110.
Previous Presentations
Portions of this work were presented as a podium presentation at the 38th Annual Meeting of the AANS/CNS Section on Disorders of the Spine and Peripheral Nerves, Las Vegas, Nevada, February 26, 2022; and as a poster presentation at the 2021 Cervical Spine Research Society Annual Meeting, Atlanta, Georgia, December 2–4, 2021.
Current Affiliations
Dr. Upadhyaya: University of North Carolina, Chapel Hill, North Carolina.
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