Prospective,multicenter clinical trial comparing M6-C compressible six degrees of freedom cervical disc with anterior cervical discectomy and fusion for the treatment of single-level degenerative cervical radiculopathy: 2-year results of an FDA investigational device exemption study

BACKGROUND CONTEXTVarious designs of total disc replacement (TDR) devices have been compared to anterior cervical discectomy and fusion (ACDF) with favorable outcomes in FDA-approved investigational device exemption trials. The design of M6-C with a compressible viscoelastic nuclear core and an annular structure is substantially different than prior designs and has previously demonstrated favorable kinematics and clinical outcomes in small case series.PURPOSETo evaluate the safety and effectiveness of the novel M6-C compressible artificial cervical disc compared with ACDF for subjects with single-level degenerative cervical radiculopathy.STUDY DESIGN/SETTINGProspective, multicenter, concurrently and historically controlled, FDA-approved investigational device exemption clinical trial.PATIENT SAMPLESubjects with one-level symptomatic degenerative cervical radiculopathy were enrolled and assigned to receive M6-C or ACDF.OUTCOME MEASURESPain and function (Neck Disability Index, VAS), quality of life (SF-36), safety, neurologic, and radiographic assessments of motion (both flexion extension and lateral bending) were performed. The primary clinical endpoint was composite clinical success (CCS) at 24 months.METHODSUsing propensity score subclassification to control for selection bias, 160 M6-C subjects were compared to a matched subset of 189 ACDF controls (46 concurrent and 143 historical controls).RESULTSBoth ACDF and M6-C subjects reported significant improvements in patient-reported outcomes at all time points over baseline. Overall SF-36 Physical Component Score and neck and arm pain scores were significantly improved for M6-C as compared to ACDF treatment. CCS and mean Neck Disability Index improvements were similar between M6-C and ACDF. Correspondingly, there were significantly fewer subjects that utilized pain medication or opioids following M6-C treatment at 24 months relative to baseline. Range of motion was maintained in subjects treated with M6-C. Subsequent surgical interventions, dysphagia rates, and serious adverse events were comparable between groups.CONCLUSIONSM6-C treatment demonstrated both safety and effectiveness for the treatment of degenerative cervical radiculopathy. Treatment with M6-C demonstrated noninferiority for the primary endpoint, indicating a similar ability to achieve CCS at 24 months. However, for the secondary endpoints, M6-C subjects demonstrated significantly improved pain and function compared to ACDF subjects, while maintaining range of motion, improving quality of life, and decreasing analgesic and opioid usage at 2 years postoperatively relative to baseline.     

Cervical kinematics and radiological changes after Discover artificial disc replacement versus fusion

Background contextThe cervical disc arthroplasty has emerged as a promising alternative to the anterior cervical discectomy and fusion (ACDF) in patients with radiculopathy or myelopathy with disc degeneration disease. The advantages of this technique have been reported to preserve the cervical mobility and possibly reduce the adjacent segment degeneration. However, no studies have compared the clinical outcomes and radiological results in patients treated with Discover artificial disc replacement to those observed in matched group of patients that have undergone ACDF.PurposeWe conducted this clinical study to compare the cervical kinematics and radiographic adjacent-level changes after Discover artificial disc replacement with ACDF.Study designAnalysis and evaluation of data acquired in a comparative clinical study.Patient sampleThe number of patients in the Discover and ACDF group were 149 and 196, respectively.Outcome measuresThe Neck Disability Index (NDI) and visual analog scale (VAS) pain score were evaluated. The range of movement (ROM) by the shell angle, the functional segment unit and global angles were measured, and the postoperative radiological changes at adjacents levels were observed.MethodsA total of 149 patients with symptomatic single or two-level cervical degenerative diseases received the Discover cervical artificial disc replacement from November 2008 to February 2010. During the same period, there were a total of 196 patients undergoing one or two-level ACDF. The average follow-up periods of the Discover disc group and ACDF group were 22.1 months and 22.5 months, respectively. Before surgery, patients were evaluated using static and dynamic cervical spine radiographs in addition to computerized tomography and magnetic resonance imaging. Static and dynamic cervical spine radiographs were obtained after surgery and then at 3- and 6-month follow-up. Then, the subsequent follow-up examinations were performed at every 6-month interval. The clinical results in terms of NDI and VAS scores, the parameters of cervical kinematics, postoperative radiological changes at adjacent levels, and complications in the two groups were statistically analyzed and compared. No funding was received for this study, and the authors report no potential conflict of interest–associated biases in the text.ResultsAlthough the clinical improvements in terms of NDI and VAS scores were achieved in both the Discover and ACDF group, no significant difference was found between the two groups for both single- (VAS p=.13, NDI p=.49) and double-level surgeries (VAS p=.28, NDI p=.21). Significant differences of cervcial kinematics occurred between the Discover and the ACDF group for both the single- and double-level surgeries at the operative segments (p<.001). Except the upper adjacent levels for the single-level Discover and ACDF groups (p=.33), significant increases in adjacent segment motion were observed in the ACDF group compared with the minimal ROM changes in adjacent segment motion noted in the Discover group, and the differences between the two groups for both single and double-level procedures were statistically significant (p<.05). There were significant differences in the postoperative radiological changes at adjacent levels between the Discover and ACDF groups for the single-level surgery (p<.001, χ²=18.18) and the double-level surgery (p=.007, χ²=7.2). No significant difference of complications was found between the Discover and ACDF groups in both single (p=.25, χ²=1.32) and double-level cases (p=.4, χ²=0.69).ConclusionsThe adjacent segment ROM and the incidence of radiographic adjacent-level changes in patients undergoing ACDF were higher than those undergoing Discover artificial disc replacement. The cervical mobility was relatively well maintained in the Discover group compared with the ACDF group, and the Discover cervical disc arthroplasty can be an effective alternative to the fusion technique.     

Total disc arthroplasty does not affect the incidence of adjacent segment degeneration in cervical spine: results of 93 patients in three prospective randomized clinical trials

Background contextAdvancements in the philosophy of “motion preservation” have led to the use of total disc arthroplasty (TDA) as an alternative to fusion for degenerative disc disease (DDD) in the cervical spine. A commonly proposed theory is that TDA could reduce the incidence of adjacent segment disease. All the published clinical studies for TDA discuss the “equal efficacy” results of different investigational device exemption (IDE) trials between TDA and anterior cervical discectomy and fusion (ACDF) but have not addressed the issue of adjacent segment disease.PurposeTo present the comparison of outcome data with respect to clinical success rates, symptom-free period, and incidence of adjacent segment disease in 93 patients with one- and two-level cervical DDD treated with TDA or ACDF in three different Food and Drug Administration (FDA) investigational trials.Study designProspective, randomized, FDA IDE trials.Patient sampleNinety-three patients with established symptomatic one-or two-level cervical disc disease who failed to respond to conservative treatment were randomized to receive TDA (59) or ACDF (34) as part of clinical trials involving three different artificial discs at our institution. Subjects were blind to the assigned group until after the surgery.Outcome measuresVisual analog pain score (VAS), Neck Disability Index, and cervical spine radiographs were collected at 6 weeks and at 3, 6, 12, 24, 36, and 48 months after surgery.MethodSuccess of the index surgery was assessed based on outcome measures at the seven data points. Success was defined as reduction by more than 30 points in both VAS and Neck Disability Index, absence of neurological deficits, and no further intervention at the index level. Adjacent segment disease was established by radiology, neurophysiology, and subsequent interventions administered to the patients.ResultsAt median follow-up of 37 months (range, 24–49 months), 64 (25 ACDF and 39 TDA) patients satisfied the criteria for clinical success. Neck Disability Index was a better predictor of outcome than pain score (p<.05). Sixteen percent of TDA patients and 18% ACDF patients developed adjacent segment degeneration and were treated actively (p=.3). Concurrent lumbar DDD significantly increased the risk of adjacent segment degeneration (p=.01). Age, gender, smoking habits, and number of levels at index surgery had no predictive value.ConclusionTotal disc arthroplasty is equivalent to ACDF for providing relief from symptoms in the treatment of one- and two-level DDD of cervical spine. The risk of developing adjacent segment degeneration is equivalent after both procedures but is significantly higher in patients with concurrent DDD in lumbar spine.     

A prospective,randomised, controlled multicentre study comparing cervical disc replacement with anterior cervical decompression and fusion

Purpose

Total cervical artificial disc replacement (TDR) simulates normal disc structure, thus avoiding the drawbacks of anterior cervical decompression and fusion (ACDF). This prospective, randomized, controlled and multicentre study aimed to evaluate clinical and radiographic outcomes by comparing cervical disc replacement using Mobi-C disc prostheses with ACDF.

Methods

This prospective, randomized, controlled and multicentre study consisted of 111 patients undergoing single-level Mobi-C disc prosthesis replacement (TDR group, n?=?55) or ACDF (n?=?56) from February 2008 to November 2009 at 11 medical centres across China. Patients were assessed before surgery, at seven days postoperation and one, three, six, 12, 24, 36 and 48 months postoperation. Clinical and neurological outcome was determined by measuring the Japanese Orthopaedic Association (JOA) scores, visual analogue scale (VAS) and Neck Disability Index (NDI). Static and dynamic radiographs were obtained of the cervical curvature, the functional spinal unit (FSU) angle and range of motion (ROM) of the cervical spine, FSU angle and treated and adjacent segments.

Results

A total of 111 patients were included and randomly assigned to either Mobi-C disc prosthesis replacement or ACDF. JOA, VAS and NDI showed statistically significant improvements 48 months after surgery (P?p?>?0.05). ROM in the ACDF group was significantly reduced at one month and remained so throughout the follow-up. By 48-months, more ACDF patients required secondary surgery (four of 56 patients).

Conclusions

Although ACDF may increase the risk of additional surgery, clinical outcomes indicated that both Mobi-C artificial cervical disc replacement and ACDF were reliable. Radiographic data showed that ROM of the cervical spine, FSU angle and treated and adjacent segments were relatively better reconstructed and maintained in the Mobi-C group compared with those in the ACDF group.     

Long-term results of the NECK trial—implanting a disc prosthesis after cervical anterior discectomy cannot prevent adjacent segment disease: five-year clinical follow-up of a double-blinded randomised controlled trial

Background contextMotion preserving anterior cervical disc arthroplasty (ACDA) in patients with cervical radiculopathy was introduced to prevent symptomatic adjacent segment disease as compared to anterior cervical discectomy and fusion (ACDF).PurposeTo evaluate the long-term outcome in patients with cervical radiculopathy due to a herniated disc undergoing ACDA, ACDF or ACD (no cage, no plate) in terms of clinical outcome measured by the Neck Disability Index (NDI). Likewise, clinically relevant adjacent segment disease is assessed as a long-term result.Study designDouble-blinded randomized controlled trial.Patient sampleA total of 109 patients with one level herniated disc were randomized to one of the following treatments: ACDA, ACDF with intervertebral cage, ACD without cage.Outcome measuresClinical outcome was measured by patients’ self-reported NDI, Visual Analogue Scale (VAS) neck pain, VAS arm pain, SF36, EQ-5D, perceived recovery and reoperation rate. Radiological outcome was assessed by radiographic cervical curvature and adjacent segment degeneration (ASD) parameters at baseline and up until five years after surgery.MethodsTo account for the correlation between repeated measurements of the same individual Generalized Estimated Equations (GEE) were used to calculate treatment effects, expressed in difference in marginal mean values for NDI per treatment group.ResultsClinical outcome parameters were comparable in the ACDA and ACDF group, but significantly worse in the ACD group, though not reaching clinical relevance. Annual reoperation rate was 3.6% in the first two years after surgery, declined to 1.9% in the years thereafter. The number of reoperations for ASD was not lower in the ACDA group, while the number of reoperations at the index level was higher after ACD, when compared to ACDF and ACDA.ConclusionsA persisting absence of clinical superiority was demonstrated for the cervical disc prosthesis five years after surgery. Specifically, clinically relevant adjacent level disease was not prevented by implanting a prosthesis. Single level ACD without implanting an intervertebral device provided worse clinical outcome, which was hypothesized to be caused by delayed fusion. This stresses the need for focusing on timely fusion in future research.     

Comparison of cervical kinematics between patients with cervical artificial disc replacement and anterior cervical discectomy and fusion for cervical disc herniation

Background contextAlthough anterior cervical discectomy and fusion (ACDF) is an effective treatment option for patients with cervical disc herniation, it limits cervical range of motion, which sometimes causes discomfort and leads to biomechanical stress at neighboring segments. In contrast, cervical artificial disc replacement (ADR) is supposed to preserve normal cervical range of motion than ACDF. A biomechanical measurement is necessary to identify the advantages and clinical implications of ADR. However, literature is scarce about this topic and in those available studies, authors used the static radiological method, which cannot identify three-dimensional motion and coupled movement during motion of one axis.PurposeThe purpose of this study was to compare the clinical parameters and cervical motion by three-dimensional motion analysis between ACDF and ADR and to investigate the ability of ADR to maintain cervical kinematics.Study designThis was a prospective case control study.Patient samplePatients who underwent ADR or ACDF for the treatment of single-level cervical disc herniation.Outcome measuresVisual analog scale (VAS), Korean version of Neck Disability Index (NDI, %), and three-dimensional motion analysis were used.MethodsThe patients were evaluated by VAS and the Korean version of the NDI (%) to assess pain degree and functional status. Cervical motions were assessed by three-dimensional motion analysis in terms of sagittal, coronal, and horizontal planes. Markers of 2.5 cm in diameter were attached at frontal polar (Fpz), center (Cz), and occipital (Oz) of 10–20 system of electroencephalography, C7 spinous process, and both acromions. These evaluations were performed preoperatively and 1 month and 6 months after surgery.ResultsThe ACDF and ADR groups revealed no significant difference in VAS, NDI (%), and cervical range of motion preoperatively. After surgery, both groups showed no significant difference in VAS and NDI (%). In motion analysis, significantly more range of motion was retained in flexion and extension in the ADR group than the ACDF group at 1 month and 6 months. There was no significant difference in lateral tilt and rotation angle. In terms of coupled motion, ADR group exhibited significantly more preserved sagittal plane motion during right and left rotation and also showed significantly more preserved right lateral bending angle during right rotation than ACDF group at 1 month and 6 months. There was no significant difference in other coupled motions.ConclusionThree-dimensional motion analysis could provide useful information in an objective and quantitative way about cervical motion after surgery. In addition, it allowed us to measure not only main motion but also coupled motion in three planes. ADR demonstrated better retained cervical motion mainly in sagittal plane (flexion and extension) and better preserved coupled sagittal and coronal motion during transverse plane motion than ACDF. ADR had the advantage in that it had the ability to preserve more cervical motions after surgery than ACDF.     

The factors that influence the postoperative segmental range of motion after cervical artificial disc replacement

Background contextAdvantages of cervical artificial disc replacement (ADR) are to preserve segmental range of motion (ROM) and avoid adjacent segmental disease. To achieve successful outcome after cervical ADR, ROM maintenance is important, but few authors have investigated the factors that influence the postoperative segmental ROM.PurposeTo evaluate the factors that influence the postoperative segmental ROM after cervical ADR.Study design/settingA retrospective clinical study.Patient sampleForty-one consecutive cervical ADR cases were analyzed.Outcome measuresDisc height, segmental and overall ROM, and clinical parameters checked with Neck Disability Index (NDI) and visual analog scale (VAS) in neck and arm pain were assessed.MethodsThere were 21 men and 20 women with a mean age of 45 years (range, 27–61 years). All cases were followed up for more than 2 years (range, 24–54 months; average, 31 months). Angles of the inserted implant on the immediate postoperative lateral radiographs, segmental and overall ROM (full flexion angle?full extension angle), disc height increment (immediate postoperative disc height?preoperative disc height), and adjacent segment changes at cephalad and caudal disc space were measured. Correlations between the factors and segmental ROM at last follow-up were analyzed.ResultsMean preoperative NDI was improved from 61.0 preoperatively to 11.5 at last follow-up, and mean VAS in the neck pain decreased from 56.8 preoperatively to 11.8 postoperatively and arm pain decreased from 68.1 to 18.0. The mean preoperative segmental ROM changed from 7.4±3.2° preoperatively to 10.4±5.9° at last follow-up, and mean preoperative disc height increased from 6.4±1.0 (4.1–8.4) mm preoperatively to 7.9±1.0 (6.3–9.9) mm postoperatively. The segmental ROM at last follow-up was not significantly correlated with preoperative segmental and overall ROM, angle of inserted implant, VAS, or age (p>.05). However, the segmental ROM at last follow-up was significantly correlated with the disc height increment (p=.046, r=0.374) and preoperative NDI (p=.026, r=0.412). The patient group with the postoperative segmental ROM greater than 10° had a significantly lower mean preoperative disc height than the group with the segmental ROM less than 10° (p=.050).ConclusionsAt a minimum of 2 years after cervical ADR, clinical outcomes were satisfactory in terms of function and pain scores. Within our results, the segmental ROM was not affected by preoperative ROM but postoperative disc height increment positively and preoperative disc height negatively.     

颈椎前路椎间盘切除融合术治疗神经根型颈椎病

目的 探讨颈椎前路椎间盘切除融合术（ACDF）治疗神经根型颈椎病（CSR）的临床疗效。方法 2017年6月—2019年6月,采用ACDF治疗CSR患者43例,患者病程为8~28个月,病变位于C_4,5节段12例、C_5,6节段14例、C_6,7节段11例、C₇~T₁节段6例。评估并比较术前及术后3、6个月颈椎功能障碍指数（NDI）及颈部和上肢疼痛视觉模拟量表（VAS）评分;测量并比较术前及术后3、6个月颈椎曲度（C_2-7 Cobb角）、椎间高度和颈椎活动度（ROM）,观察并发症发生情况。结果 所有患者术后颈椎曲度、NDI、颈部和上肢疼痛VAS评分均较术前改善,差异有统计学意义（P < 0.05）;椎间高度、颈椎ROM与术前相比,差异无统计学意义（P > 0.05）。发生脑脊液漏2例,术后血肿及感染2例。结论 ACDF治疗CSR可取得较好的疗效,其可改善颈椎曲度,恢复神经功能。     

How do C2 tilt and C2 slope correlate with patient reported outcomes in patients after anterior cervical discectomy and fusion?

BACKGROUND/CONTEXTC2 tilt and C2 slope are quick and easy measurements to obtain on lateral radiographs and may be used to determine overall cervical sagittal alignment; however, the influence of these measurements on patient outcomes has not been well established in literature.PURPOSETo determine if C2 tilt and/or C2 slope predict patient outcomes better compared with conventional radiographic measures after an anterior cervical discectomy and fusion (ACDF).STUDY DESIGN/SETTINGRetrospective cohort study.PATIENT SAMPLEA total of 249 patients who underwent 1 to 3 level ACDF to address radiculopathy and/or myelopathy at a single academic institution between 2011 and 2015 were identified. Patients with less than 1 year of follow-up were excluded.OUTCOME MEASURESPatient Reported Outcomes: Neck Disability Index (NDI), Physical Component Score-12 (PCS-12), and Mental Component Score (MCS-12), Visual Analog Score (VAS) Neck and Arm scoresCervical radiographic measurements: C2 tilt, C2 slope, C2–C7 lordosis, cervical SVA, T1 slope, T1 slope minus cervical lordosis (TS-CL), and C2–C7 ROMMETHODSPearson correlation tests were performed to assess for significant associations between radiographic measurements and patient outcomes. Multiple linear regression models were developed adjusting for demographics and radiographic parameters to determine which factors were predictive of patient outcomes.RESULTSC2 tilt and TS-CL correlated with all postoperative physical outcome scores (NDI, PCS-12, VAS Neck and ARM; p<.05), however no association was seen between C2 slope and postoperative outcomes. After accounting for the presence of subaxial deformity, C2 tilt and TS-CL remained strongly correlated to patient outcome scores. With multiple linear regression, C2 tilt was a significant predictor for NDI, whereas TS-CL was a significant predictor for PCS-12, VAS Neck and VAS Arm.CONCLUSIONSC2 tilt significantly correlated with well-described conventional cervical parameters as well as postoperative physical outcomes measures, especially NDI, on multivariate analysis. C2 tilt may provide an easy and practical tool for predicting physical outcomes after ACDF.     

Patients with radiculopathy have worse baseline disability and greater improvements following anterior cervical discectomy and fusion compared to patients with myelopathy

BACKGROUND CONTEXTAnterior cervical discectomy and fusion (ACDF) is commonly performed in patients with radiculopathy and myelopathy. Although the goal of surgery in patients with radiculopathy is to improve function and reduce pain, patients with myelopathy undergo surgery to halt disease progression. Although the expectations between these preoperative diagnoses are generally understood to be disparate by spine surgeons, there is limited literature demonstrating their discordant outcomes.PURPOSETo compare improvements in patient reported outcome measures (PROMs) for patients undergoing ACDF for myelopathy or radiculopathy. Secondarily, we analyzed the proportion of patients who attain the minimum clinically important difference (MCID) postoperatively using thresholds derived from radiculopathy, myelopathy, and mixed cohort studies.STUDY DESIGN/SETTINGSingle institution retrospective cohort studyPATIENT SAMPLEPatients undergoing primary, elective ACDF with a preoperative diagnosis of radiculopathy or myelopathy and a complete set of preoperative and one-year postoperative PROMs.OUTCOME MEASURESOutcome measures included the following PROMs: Short-Form 12 Physical Component (PCS-12) and Mental Component (MCS-12) scores, the Visual Analog Scale (VAS) Arm score, and the Neck Disability Index (NDI). Hospital readmissions and revision surgery were also collected and evaluated.METHODSPatients undergoing an ACDF from 2014 to 2020 were identified and grouped based on preoperative diagnosis (radiculopathy or myelopathy). We utilized “general MCID” thresholds from a cohort of patients with degenerative spine conditions, and “specific MCID” thresholds generated from cohorts of patients with myelopathy or radiculopathy, respectively. Multivariate linear regressions were performed for delta (?) PROMs and multivariate logistic regressions were performed for both general and specific MCID improvements.RESULTSA total of 798 patients met inclusion criteria. Patients with myelopathy had better baseline function and arm pain (MCS-12: 49.6 vs 47.6, p=.018; VAS Arm: 3.94 vs 6.02, p<.001; and NDI: 34.1 vs 41.9, p<.001), were older (p<.001), had more comorbidities (p=.014), more levels fused (p<.001), and had decreased improvement in PROMs following surgery compared to patients with radiculopathy (?PCS-12: 4.76 vs 7.21, p=.006; ?VAS Arm: -1.69 vs -3.70, p<.001; and ?NDI: -11.94 vs -18.61, p<.001). On multivariate analysis, radiculopathy was an independent predictor of increased improvement in PCS-12 (β=2.10, p=.019), ?NDI (β=-5.36, p<.001), and ?VAS Arm (β=-1.93, p<.001). Radiculopathy patients were more likely to achieve general MCID improvements following surgery (NDI: Odds ratio (OR): 1.42, p=.035 and VAS Arm: OR: 2.98, p<.001), but there was no difference between patients with radiculopathy or myelopathy when using radiculopathy and myelopathy specific MCID thresholds (MCS-12: p=.113, PCS-12: p=.675, NDI: p=.108, and VAS Arm: p=.314).CONCLUSIONSPatients undergoing ACDF with myelopathy or radiculopathy represent two distinct patient populations with differing treatment indications and clinical outcomes. Compared to radiculopathy, patients with myelopathy have better baseline function, decreased improvement in PROMs, and are less likely to reach MCID using general threshold values, but there is no difference in the proportion reaching MCID when using specific threshold values.LEVEL OF EVIDENCEIRB     

Predictive factors for arm pain, neck pain, neck specific disability and health after anterior cervical decompression and fusion

Summary Background. Predictive factors for a low arm and neck pain, and good health after anterior cervical decompression and fusion (ACDF) with a cervical carbon fibre intervertebral fusion cage (CIFC) are still lacking. Method. A prospective consecutive study to investigate which preoperative factors that could predict a good outcome with regard to arm pain, neck pain, Neck Disability Index (NDI) and general health three years after ACDF with CIFC was conducted. Thirty-four patients were included before surgery. Measurements took place the day before, six months, one year and three years after ACDF. Findings. In multivariate analysis, to be a non-smoker before surgery was the most important factor for a low postoperative arm pain, a low pain frequency was the most important factor for low postoperative neck pain, normal rating on Distress and Risk Assessment Method (DRAM) was the most important factor for high function on NDI and a low initial pain intensity was the most important factor for good postoperative health. For all outcome variables a normal rating on DRAM was an important factor for a good outcome. Conclusions. Non-smoking, a low pain level and normal rating on DRAM were the best preoperative predictors of a good outcome in ACDF. Inclusion criteria for surgery should be based on a bio psychosocial model and DRAM seems to be useful for including the traditional inclusion criteria.     

Impact of preoperative weakness and duration of symptoms on health-related quality-of-life outcomes following anterior cervical discectomy and fusion

BACKGROUND CONTEXTThe majority of patients with preoperative upper extremity weakness show improvements in motor function after anterior cervical discectomy and fusion (ACDF). Although numerous studies have examined both the extent and time course to which motor function can be expected to improve, few have shown that these improvements in motor function translate to improved health related quality of life (HRQOL) outcomes.PURPOSEThe purpose of this study was to examine the effect of preoperative weakness and duration of symptoms on HRQOL outcomes in patients who underwent ACDF.STUDY DESIGNRetrospective cohort study.PATIENT SAMPLEAdult patients who underwent an ACDF procedure at an academic hospital from January 2015 to December 2016 by a fellowship-trained spine surgeon.OUTCOME MEASURESThe primary outcomes of interest were HRQOL outcomes: Short Form-12 Physical/Mental Component Scores (SF-12 PCS/MCS), Neck Disability Index (NDI), and Visual Analog Scale Arm/Neck scores (VAS Arm/Neck).METHODSPatient demographics, surgical case characteristics, and motor strength exams were collected in patients who underwent ACDF over a 2-year period. Preoperative weakness was defined by a strength grade ≤3 (on a scale from 0 to 5) in at least one upper extremity muscle group. Multivariate linear regression analysis was performed to determine the effect of the preoperative weakness on HRQOL outcomes.RESULTSOf the 276 patients identified, 45 (16.3%) showed evidence of preoperative weakness, 44 (97.8%) of which showed subsequent postoperative motor improvements after ACDF. All patients reported significant improvements in all HRQOL outcome measures. Patients with preoperative weakness reported significantly worse preoperative VAS Arm (6.9 vs. 5.2; p=.01) and VAS Neck (6.1 vs. 4.8; p=.02) pain scores. Compared with patients without preoperative weakness, those with preoperative weakness reported significantly more improvement in NDI (β: −10.9; p=.001). Patients with symptoms greater than or equal to 12 months and preoperative weakness showed significantly less improvement in NDI (β: 14.8; p=.03).CONCLUSIONSPatients with preoperative weakness generally exhibited worse pain and HRQOL measures preoperatively, and showed greater potential for improvement after ACDF. Patients with a shorter duration of preoperative weakness had greater potential for improvement in HRQOL measures after ACDF compared with those with longer duration of symptoms. ACDF is an effective procedure to improve strength and HRQOL measures across all patient groups under appropriate indications.     

Establishing a relationship using CT between facet distraction and clinical outcomes after ACDF

BACKGROUND CONTEXTAnterior cervical discectomy and fusion (ACDF), the gold standard treatment for radiculopathy and myelopathy, has the potential risk of inducing facet-mediated pain through over-distraction. However, the relationship between the clinical outcomes and facet distraction after ACDF remains unclear.PURPOSETo measure facet distraction using computed tomography (CT) and compare the results with the clinical outcomes after ACDF.STUDY DESIGNRetrospective cohort study.PATIENT SAMPLEA consecutive series of patients (n = 144) who underwent a single-level ACDF were included.OUTCOME MEASURESInterfacet distance on preoperative and postoperative lateral cervical radiographs and CT. Visual analog scale for neck pain (VASn), and arm pain (VASa), neck disability index (NDI), the Short Form 36-item health survey (SF-36) were used for clinical outcomes.METHODSEach patient underwent plain radiography of the lateral cervical spine preoperatively, immediately and two years postsurgery. CT was performed preoperatively, and at 3 days and 1-year postsurgery. The inter-facet distance was measured at each time point, and changes in values from the preoperative distance were noted and used for study. Patient-reported outcome measures were obtained preoperatively and at 2-year follow-up. Receiver operating characteristic (ROC) curves were generated to derive the critical facet distraction point.RESULTSThe 3 weeks postoperative VASn score was the most severe and showed a tendency to decrease during the follow-up period. There was a significant positive correlation between the change value of facet distraction measured using CT and 3 weeks postoperative VASn score. ROC curve analysis showed that the cut-off value of Δ facet distraction was 1.8 mm. The over-distraction group (Δ facet distraction ≥1.8 mm, n = 75) showed significantly worse clinical outcomes than the control group (Δ facet distraction <1.8 mm, n = 69), including neck and arm pain VAS scores at all time points until the final 2-year follow-up.CONCLUSIONThe change value of facet distraction measured using CT rather than plain radiography correlated better with neck pain, and over-distraction contributed to adverse long-term outcomes, including neck and arm pain after ACDF. Additionally, an over-distraction of ≥1.8 mm may cause radiculopathy of adjacent segments along with facet-mediated axial pain; therefore, cage height should be carefully determined to avoid over-distraction during ACDF.     

Comparison of clinical outcomes between cervical disc arthroplasty and anterior cervical discectomy and fusion for the treatment of single-level cervical spondylosis: a 10-year follow-up study

BACKGROUND CONTEXTThe theoretical advantage of cervical disc arthroplasty includes preserved motion at the cervical level, which may reduce degeneration of the adjacent segments. The long-term follow-up results are still controversial.PURPOSEThe present study aimed to retrospectively study the long-term efficacy and complications of cervical disc arthroplasty using a single commercially-available device in a single center.STUDY DESIGNThis was a propensity-score matched cohort study.PATIENT SAMPLEThis study enrolled 148 single-level cervical degenerative disease patients from January 2009 to March 2012. After 1:1 propensity score matching, 39 patients remained in the ACDF or ACDR groups.OUTCOME MEASURESThe outcome measures were neurological functions (Neck Disability Index (NDI) and Japan Orthopedic Association (JOA) scores), radiographic evaluations (cervical curvature, operative segment range of motion, degenerative condition of adjacent segments, heterotopic ossification (HO) of the surgical segment), and complications.METHODSNDI and JOA scores were used to evaluate patient neurological functions. Cervical curvature (C2-C7 Cobb angle) and operative segment range of motion (ROM) were compared between the two groups. Grading criteria for osteophyte formation were used to evaluate the degenerative condition of adjacent segments. HO after ACDR was graded according to the McAfee grading method.RESULTSThe average follow-up time was 119.3 ±17.2 months. Satisfactory improvements in neurological function were obtained for both the ACDR and ACDF groups. There were no significant differences in VAS or NDI scores between the two groups. In the ACDR group, the ROM of the operative segment increased from 6.7 ±4.3° before the operation to 8.9 ±3.5° on the second day after the operation (p<.001). The ROM of the operative segment was 8.1 ±4.0° at the 1-year follow-up, 7.2 ±3.6° at the 2-year follow-up, 5.7 ±4.5° at the 5-year follow-up and 4.3 ±3.9° at the last follow-up. ASD was more likely to develop in the caudal adjacent segments and progressed with the follow-up time. At the last follow-up, HO was present in 27 patients (69.23%), while high-grade HO (McAfee scores III and IV) was detected in 6 patients (15.38%).CONCLUSIONSThrough nearly 10 years of follow-up, ACDR was as effective as ACDF for treating single-level degenerative cervical disc disease. However, HO and the role of ACDR in the protection of ASD remains to be further observed and followed up.     

颈椎矢状面活动度影像学改良测量方法的初步应用

目的 提出一种改良颈椎矢状面活动度(ROM)影像学测量方法,并与传统测量方法进行比较.方法 纳入接受颈椎前路椎间盘切除融合术(ACDF)治疗的72例颈椎病患者为研究对象,其中脊髓型颈椎病(CSM)43例,神经根型颈椎病(CSR)29例.利用术前颈椎仰伸位与屈曲位侧位X线片,由2名脊柱外科医师分别采用传统测量法和改良测量法对颈椎ROM进行测量.分析2种测量方法的观察者内一致性、观察者间一致性,并对2种测量方法的结果进行相关性分析和比较.结果 按性别、年龄、病种分层,2种方法测量的颈椎ROM差异均无统计学意义(P>0.05),且2种方法测量的颈椎ROM均随年龄的增大而下降.传统方法和改良方法均具有高度观察者内一致性(组内相关系数分别为0.961、0.991)和观察者间一致性(组内相关系数分别为0.964、0.993),且改良方法的观察者内一致性和观察者间一致性高于传统方法.2种方法的测量结果呈高度正相关(r=0.987,P<0.01).对2种方法前后2次测量结果的差值进行比较,结果显示,2种方法不同测量者之间2次测量结果的差值差异均无统计学意义(P>0.05);而对无论哪名测量者,不同方法之间2次测量结果的差值差异均有统计学意义(P<0.01).结论 改良方法测量颈椎ROM具有高度观察者内一致性和观察者间一致性,采用改良方法能够提高颈椎ROM测量的精准度.     

Confirmatory factory analysis of the Neck Disability Index in a general problematic neck population indicates a one-factor model

Background contextThe Neck Disability Index frequently is used to measure outcomes of the neck. The statistical rigor of the Neck Disability Index has been assessed with conflicting outcomes. To date, Confirmatory Factor Analysis of the Neck Disability Index has not been reported for a suitably large population study. Because the Neck Disability Index is not a condition-specific measure of neck function, initial Confirmatory Factor Analysis should consider problematic neck patients as a homogenous group.PurposeWe sought to analyze the factor structure of the Neck Disability Index through Confirmatory Factor Analysis in a symptomatic, homogeneous, neck population, with respect to pooled populations and gender subgroups.Study designThis was a secondary analysis of pooled data.Patient sampleA total of 1,278 symptomatic neck patients (67.5% female, median age 41 years), 803 nonspecific and 475 with whiplash-associated disorder.Outcome measuresThe Neck Disability Index was used to measure outcomes.MethodsWe analyzed pooled baseline data from six independent studies of patients with neck problems who completed Neck Disability Index questionnaires at baseline. The Confirmatory Factor Analysis was considered in three scenarios: the full sample and separate sexes. Models were compared empirically for best fit.ResultsTwo-factor models have good psychometric properties across both the pooled and sex subgroups. However, according to these analyses, the one-factor solution is preferable from both a statistical perspective and parsimony. The two-factor model was close to significant for the male subgroup (p<.07) where questions separated into constructs of mental function (pain, reading headaches and concentration) and physical function (personal care, lifting, work, driving, sleep, and recreation).ConclusionsThe Neck Disability Index demonstrated a one-factor structure when analyzed by Confirmatory Factor Analysis in a pooled, homogenous sample of neck problem patients. However, a two-factor model did approach significance for male subjects where questions separated into constructs of mental and physical function. Further investigations in different conditions, subgroup and sex-specific populations are warranted.     

Is the likelihood of dysphagia different in patients undergoing one-level versus two-level anterior cervical discectomy and fusion?

BACKGROUND CONTEXTDysphagia following anterior cervical discectomy and fusion (ACDF) is a common complication, the etiology of which has not been established. Given that one potential mechanism for dysphagia is local tissue edema, it is thought that a greater number of operative levels may result in higher dysphagia rates. However, prior reports comparing one-level to two-level ACDF have shown varying results.PURPOSETo determine if there is a difference in dysphagia between one-level and two-level ACDF.STUDY DESIGN/SETTINGRetrospective review of prospectively collected data.PATIENT SAMPLEPatients who underwent one- or two-level ACDF with a plate-graft construct by a single-surgeon at a high-volume academic medical center.OUTCOME MEASURESNeck Disability Index, Visual Analog Scale for neck pain and arm pain, Short Form-12 physical and mental health components, and Swallowing Quality of Life (SWAL-QOL) Questionnaire.METHODSPatient demographics, operative data, and patient-reported outcome measures (PROMs; Neck Disability Index, Visual Analog Scale, Short Form-12, and SWAL-QOL) of patients undergoing one- and two-level ACDF were compared using Fisher exact test for categorical variables and Student's t test for continuous variables. Regression analyses were conducted to identify factors associated with 6- and 12-week SWAL-QOL scores in order to determine whether the number of surgical levels impacts these outcomes.RESULTSFifty-eight patients (22 one-level and 36 two-level ACDF) were included. Patients undergoing two-level fusions were older (54.17+8.67 vs 48.06+10.68 years, p=.02) and had longer operative times (69.08+10.51 vs 53.5+14.35 minutes, p<.0001). There were no other significant differences in demographics or operative data. Both groups showed a statistically significant improvement in PROMs from preoperatively to 12 weeks. There was no difference in PROMs or dysphagia rates between groups at any time-point. Younger age (p=.023), male sex (p=.021), longer operative times (p=.068), and worse preoperative SWAL-QOL (p<.0001) were associated with dysphagia at 6 weeks. Preoperative SWAL-QOL was the only variable associated with dysphagia at 12 weeks (p=.003). Operative time of >61.5 minutes had a sensitivity and specificity of 62.1% for worse dysphagia scores at 6 weeks compared with baseline.CONCLUSIONSThe results of our study indicate that there is no difference in the degree of postoperative dysphagia in one- versus two-level ACDF. However, other variables associated with increased postoperative dysphagia in our population included younger age, male sex, procedural time >61.5 minutes, and worse preoperative dysphagia. Larger studies are required to confirm these findings and identify additional risk factors for postoperative dysphagia.     

Choice of plate may affect outcomes for single versus multilevel ACDF: results of a prospective randomized single-blind trial

Background contextConflicting views exist according to the individual philosophy about various plate designs that can be used in anterior cervical discectomy and fusion (ACDF) to achieve clinical and radiological improvement within shortest time period. No prospective randomized study has ever been conducted to clarify the relationship between clinical outcomes, fusion rates, and the choice of plate (static vs. dynamic design).PurposeTo compare the clinical and radiological outcomes of patients treated with one-level or multiple levels ACDF using cervical plates of dynamic (slotted-holes) versus static (fixed-holes) design.Study designSingle masked, prospective, randomized study.Patient sampleOver a 4-year period, 66 patients (M:F=37:29) had ACDF using either dynamic (n=33) or static (n=33) plates for intractable radiculopathy as the result of degenerative cervical spine disease. Overall, 28 patients had single-level fusion and 38 had two or three levels fused.Outcome measuresVisual Analogue Pain scores (VASs), Neck Disability Index (NDI), and radiological criteria of established fusion.MethodsThe qualifying subjects were randomized to receive ACDF using either fixed-holes (static) or the slotted-holes (dynamic) anterior cervical plates. Clinical and radiographic data were collected and analyzed. Paired-sample t test was used to correlate clinical and radiological outcomes and General Linear Model Analysis of Variance (GLM ANOVA) with repeated measures was used to detect outcome differences between the two groups for single and multiple fusions.ResultsAt a mean follow-up of 16 months (range, 12–24), 49 patients (73.7%) had clinical success and 56 (85%) showed radiological fusion. Although clinical success was a predictor of fusion (p=.043), the reverse was not true (p=.61). In single-level fusion, no statistical difference of outcome was observed between the two groups but multilevel fusions with dynamic plate showed significantly lower VAS and NDI than those with static plates (p=.050).ConclusionsAlthough clinical improvement is a good predictor of successful ACDF, radiological evidence of fusion alone is not reliable as a parameter of success. The design of plate does not affect the outcomes in single-level fusions but statistics indicate that multiple-level fusions may have better clinical outcome when a dynamic plate design is used.     

Clinical outcome following anterior cervical discectomy and fusion with and without anterior cervical plating for the treatment of cervical disc herniation—a 25-year follow-up study

Extreme long-term clinical outcome studies following anterior cervical discectomy and fusion (ACDF) with an autologous iliac crest with and without Caspar plating (ACDF + CP) for the treatment of radiculopathy caused by cervical disc herniation (CDH) are extremely rare. Hospital records of patients who underwent ACDF or ACDF + CP for the treatment of CDH at least 17 years ago were reviewed. Information about diagnosis, surgery, pre- and postoperative clinical process, and repeated procedure was analyzed. At final follow-up, patients were reviewed with a standardized questionnaire including the current neurological status, Neck Disability Index (NDI), Odom’s criteria, a modified EQ-5D, and limitations in quality of life. One hundred twenty-two patients with a mean follow-up of 25 years were evaluated. ACDF was performed in 80 and ACDF + CP in 42 patients, respectively. At final follow-up, 81.1% of patients were free of radicular pain and had no repeated procedure. According to Odom’s criteria, 86.1% of good to excellent functional recovery was noted. The mean NDI and EQ-5D was 14% and 5 points, respectively. There was no significant difference in the assessed clinical outcome parameters between patients treated with ACDF and ACDF + CP. The rate for repeated procedure due to degenerative cervical disorders was 10.7 and 7.4% due to symptomatic adjacent segment disease with 25 years. ACDF and ACDF + CP achieved a high rate radicular pain relief (89.3%) and clinical success (86.1%) for the treatment of CDH within a 25 years follow-up. No statistical difference concerning clinical outcome and rate of repeated procedure was detected.     

What is the role of dynamic cervical spine radiographs in predicting pseudarthrosis revision following anterior cervical discectomy and fusion?

Background ContextPostoperative dynamic radiographs are used to assess fusion status after anterior cervical discectomy and fusion (ACDF) with comparable accuracy to computed tomography (CT) scans.PurposeTo (1) determine if dynamic radiographs accurately predict pseudarthrosis revision in a cohort of largely asymptomatic patients who underwent ACDF, (2) determine how adjacent segment motion is affected by fusion status, and (3) analyze how clinical outcomes differ between patients with symptomatic and asymptomatic pseudarthrosis.Study DesignRetrospective cohort study.Patient SamplePatients ≥ 18 years who underwent primary one- to four-level ACDF at a single institution over a 10-year period.Outcome MeasuresInterspinous motion on preoperative and postoperative flexion-extension radiographs and preoperative and postoperative Visual Analogue Scale for Neck Pain (VAS Neck) and Arm Pain (VAS Arm), Neck Disability Index (NDI), Modified Japanese Orthopaedic Association scale (mJOA), Mental and Physical Component Scores of the Short-Form 12 (SF-12) Health Survey (MCS-12 and PCS-12)MethodsThe difference in spinous process motion between flexion and extension radiographs was used to determine motion at each level of the ACDF construct. Pseudarthrosis was defined as ≥ 1 mm spinous process motion on dynamic radiographs. A receiver operating characteristic (ROC) curve was generated to predict the probability of surgical revision for pseudarthrosis based on millimeters of interspinous motion at each instrumented level. Patient reported outcome measures (PROMs) were used to assess the effect of pseudarthrosis on clinical outcomes. Alpha was set at p<.05.ResultsA total of 597 patients met inclusion criteria including 1,203 ACDF levels. Of those, 215 patients (36.0%) were diagnosed with a pseudarthrosis on dynamic radiographs with 29 patients (4.9%) requiring pseudarthrosis revision. ROC analysis identified a “cutoff” value of 1.00 mm of interspinous process motion for generating an optimal area under the curve (AUC). The negative predictive value (NPV) was 99.6%, whereas the positive predictive value (PPV) was 13.7%. When analyzing adjacent segment motion, the Δ supra-adjacent interspinous process motion (ISM) was significantly lower for patients with a superior construct pseudarthrosis (-1.06 mm vs. 1.80 mm, p<.001), whereas the Δ infra-adjacent level ISM was significantly lower for patients with an inferior construct pseudarthrosis (-1.21 mm vs. 2.15 mm, p<.001). Patients with a pseudarthrosis not requiring revision had worse postoperative NDI (29.3 vs. 23.4, p=.027), VAS Neck (3.40 vs. 2.63, p=.012), and VAS Arm (3.09 vs. 1.85, p=.001) scores at 3 months, but not 1-year, compared with patients who were fused. Patients requiring pseudarthrosis revision had higher 1-year postoperative NDI (38.0 vs. 23.7, p=.047) and lower 1-year postoperative Δ VAS Arm (-0.22 vs. -2.97, p=.016) scores.ConclusionsOne-year postoperative dynamic radiographs have a greater than 99% negative predictive value for identifying patients requiring pseudarthrosis revision, but they have a low positive predictive value. Most patients with a pseudarthrosis remain asymptomatic with similar 1-year postoperative patient-reported outcomes compared with patients without a pseudarthrosis.