Tag: anterior cervical discectomy and fusion

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Safety of Outpatient Anterior Cervical Discectomy and Fusion: A Systematic Review and Meta-Analysis

Neurosurgery 86:30–45, 2020

Anterior cervical discectomy and fusion (ACDF) is being increasingly offered on an outpatient basis. However, the safety profile of outpatient ACDF remains poorly defined.

OBJECTIVE: To review the medical literature on the safety of outpatient ACDF.

METHODS: We systematically reviewed the literature for articles published before April 1, 2018, describing outpatient ACDF and associated complications, including incidence of reoperation, stroke, thrombolytic events, dysphagia, hematoma, and mortality. A random-effects analysis was performed comparing complications between the inpatient and outpatient groups.

RESULTS: We identified 21 articles that satisfied the selection criteria, of which 15 were comparative studies. Most of the existing studies were retrospective, with a lack of level I or II studies on this topic. We found no statistically significant difference between inpatient and outpatient ACDF in overall complications, incidence of stroke, thrombolytic events, dysphagia, and hematoma development. However, patients undergoing outpatient ACDF had lower reported reoperation rates (P < .001), mortality (P < .001), and hospitalization duration (P < .001).

CONCLUSION: Our meta-analysis indicates that there is a lack of high level of evidence studies regarding the safety of outpatient ACDF. However, the existing literature suggests that outpatient ACDF can be safe, with low complication rates comparable to inpatient ACDF in well-selected patients. Patients with advanced age and comorbidities such as obesity and significant myelopathy are likely not suitable for outpatient ACDF. Spine surgeons must carefully evaluate each patient to decide whether outpatient ACDF is a safe option. Higher quality, large prospective randomized control trials are needed to accurately demonstrate the safety profile of outpatient ACDF.

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Two-level cervical disc arthroplasty versus anterior cervical discectomy and fusion: 10-year outcomes of a prospective, randomized investigational device exemption clinical trial

J Neurosurg Spine 31:508–518, 2019

The authors assessed the 10-year clinical safety and effectiveness of cervical disc arthroplasty (CDA) to treat degenerative cervical spine disease at 2 adjacent levels compared to anterior cervical discectomy and fusion (ACDF).

METHODS A prospective, randomized, controlled, multicenter FDA-approved clinical trial was conducted comparing the low-profile titanium ceramic composite–based Prestige LP Cervical Disc (n = 209) at two levels with ACDF (n = 188). Ten-year follow-up data from a postapproval study were available on 148 CDA and 118 ACDF patients and are reported here. Clinical and radiographic evaluations were completed preoperatively, intraoperatively, and at regular postoperative follow-up intervals for up to 10 years. The primary endpoint was overall success, a composite variable that included key safety and efficacy considerations. Ten-year follow-up rates were 86.0% for CDA and 84.9% for ACDF.

RESULTS From 2 to 10 years, CDA demonstrated statistical superiority over ACDF for overall success, with rates at 10 years of 80.4% versus 62.2%, respectively (posterior probability of superiority [PPS] = 99.9%). Neck Disability Index (NDI) success was also superior, with rates at 10 years of 88.4% versus 76.5% (PPS = 99.5%), as was neurological success (92.6% vs 86.1%; PPS = 95.6%). Improvements from preoperative results in NDI and neck pain scores were consistently statistically superior for CDA compared to ACDF. All other study effectiveness measures were at least noninferior for CDA compared to ACDF through the 10-year follow-up period, including disc height. Mean angular ranges of motion at treated levels were maintained in the CDA group for up to 10 years. The rates of grade IV heterotopic ossification (HO) at the superior and inferior levels were 8.2% and 10.3%, respectively. The rate of severe HO (grade III or IV) did not increase significantly from 7 years (42.4%) to 10 years (39.0%). The CDA group had fewer serious (grade 3–4) implantrelated or implant/surgical procedure–related adverse events (3.8% vs 8.1%; posterior mean 95% Bayesian credible interval [BCI] of the log hazard ratio [LHR] -0.92 [-1.88, -0.01]). The CDA group also had statistically fewer secondary surgical procedures at the index levels (4.7%) than the ACDF group (17.6%) (LHR [95% BCI] -1.39 [-2.15, -0.61]) as well as at adjacent levels (9.0% vs 17.9%).

CONCLUSIONS The Prestige LP Cervical Disc, implanted at two adjacent levels, maintains improved clinical outcomes and segmental motion 10 years after surgery and is a safe and effective alternative to fusion.

Clinical trial registration no.: NCT00637156 (clinicaltrials.gov)

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Effects of smoking on cervical disc arthroplasty

J Neurosurg Spine 30:168–174, 2019

Cigarette smoking can adversely affect bone fusion in patients who undergo anterior cervical discectomy and fusion. However, there is a paucity of data on smoking among patients who have undergone cervical disc arthroplasty (CDA). The present study aimed to compare the clinical and radiological outcomes of smokers to those of nonsmokers following CDA.

METHODS The authors retrospectively reviewed the records of consecutive patients who had undergone 1- or 2-level CDA for cervical disc herniation or spondylosis and had a minimum 2-year follow-up. All patients were grouped into a smoking group, which consisted of those who had consumed cigarettes within 6 months prior to the CDA surgery, or a nonsmoking group, which consisted of those who had not consumed cigarettes at all or within 6 months of the CDA. Clinical outcomes were evaluated according to the visual analog scale for neck and arm pain, Neck Disability Index, Japanese Orthopaedic Association Scale, and Nurick Scale at each time point of evaluation. Radiological outcomes were assessed using radiographs and CT for multiple parameters, including segmental range of motion (ROM), neutral lordotic curve, and presence of heterotopic ossification (HO).

RESULTS A total of 109 patients completed at least 2 years of follow-up and were analyzed (mean follow-up 42.3 months). There were 89 patients in the nonsmoking group and 20 in the smoking group. The latter group was younger and predominantly male (both p < 0.05) compared to the nonsmoking group. The two groups had similar improvements in all clinical outcomes after CDA compared to preoperatively. Radiological evaluations were also very similar between the two groups, except for two factors. The smoking group had well-preserved segmental ROM after CDA at an average of 8.1° (both pre- and postoperation). However, while the nonsmoking group remained mobile, segmental ROM decreased significantly (8.2° to 6.9°, p < 0.05) after CDA. There was a trend toward more HO development in the nonsmoking group than in the smoking group, but the difference was without significance (59.6% vs 50.0%, p = 0.43).

CONCLUSIONS During an average 3.5 years of follow-up after 1- and 2-level CDA, cigarette smokers and nonsmokers had similar improvements in clinical outcomes. Moreover, segmental mobility was slightly better preserved in smokers. Since smoking status did not negatively impact outcomes, CDA may be a reasonable option for selected patients who have smoked.

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Fivefold higher rate of pseudarthrosis with polyetheretherketone interbody device than with structural allograft used for 1-level anterior cervical discectomy and fusion

J Neurosurg Spine 30:46–51, 2019

Common interbody graft options for anterior cervical discectomy and fusion (ACDF) include structural allograft and polyetheretherketone (PEEK). PEEK has gained popularity due to its radiolucency and its elastic modulus, which is similar to that of bone. The authors sought to compare the rates of pseudarthrosis, a lack of solid bone growth across the disc space, and the need for revision surgery with the use of grafts made of allogenic bone versus PEEK.

METHODS The authors retrospectively reviewed 127 cases in which patients had undergone a 1-level ACDF followed by at least 1 year of radiographic follow-up. Data on age, sex, body mass index, tobacco use, pseudarthrosis, and the reoperation rate for pseudarthrosis were collected. These data were analyzed by performing a Pearson’s chi-square test.

RESULTS Of 127 patients, 56 had received PEEK implants and 71 had received allografts. Forty-six of the PEEK implants (82%) were stand-alone devices. There were no significant differences between the 2 treatment groups with respect to patient age, sex, or body mass index. Twenty-nine (52%) of 56 patients with PEEK implants demonstrated radiographic evidence of pseudarthrosis, compared to 7 (10%) of 71 patients with structural allografts (p < 0.001, OR 9.82; 95% CI 3.836–25.139). Seven patients with PEEK implants required reoperation for pseudarthrosis, compared to 1 patient with an allograft (p = 0.01, OR 10.00; 95% CI 1.192–83.884). There was no significant difference in tobacco use between the PEEK and allograft groups (p = 0.586).

CONCLUSIONS The results of this study demonstrate that the use of PEEK devices in 1-level ACDF is associated with a significantly higher rate of radiographically demonstrated pseudarthrosis and need for revision surgery compared with the use of allografts. Surgeons should be aware of this when deciding on interbody graft options, and reimbursement policies should reflect these discrepancies.

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Comparison of Multilevel Cervical Disc Replacement and Multilevel Anterior Discectomy and Fusion: A Systematic Review of Biomechanical and Clinical Evidence

World Neurosurg. (2018) 116:94-104

OBJECTIVE: The aim of this study was to comprehensively compare the clinical and biomechanical efficiency of anterior cervical discectomy and fusion (ACDF) with anterior cervical disc replacement (ACDR) for treatment of multilevel cervical disc disease using a meta-analysis and systematical review.

METHODS: A literature search was performed using PubMed, MEDLINE, EMBASE, and the Cochrane Library for articles published between January 1960 and December 2017. Both clinical and biomechanical parameters were analyzed. Statistical tests were conducted by Revman 5.3. Nineteen studies including 10 clinical studies and 9 biomechanical studies were filtered out.

RESULTS: The pooled results for clinical efficiency showed that no significant difference was observed in blood loss (P [ 0.09; mean difference [MD], 7.38; confidence interval [CI], e1.16 to 15.91), hospital stay (P[ 0.33; MD, L0.25; CI, L0.76 to 0.26), Japanese Orthopaedic Association scores (P [ 0.63; MD, L0.11; CI, L0.57 to 0.34), visual analog scale (P [ 0.08; MD, L0.50; CI, L1.06 to 0.05), and Neck Disability Index (P [ 0.33; MD, L0.55; CI, L1.65 to 0.56) between the 2 groups. Compared with ACDF, ACDR did show increased surgical time (P [ 0.03; MD, 31.42; CI, 2.71e60.14). On the other hand, ACDR showed increased index range of motion (ROM) (P < 0.00001; MD, 13.83; CI, 9.28e 18.39), lower rates of adjacent segment disease (ASD) (P [ 0.001; odds ratio [OR], 0.27; CI, 0.13e0.59), complications (P [ 0.006; OR, 0.62; CI, 0.45e0.87), and rate of subsequent surgery (P < 0.00001; OR, 0.25; CI, 0.14e0.44). As for biomechanical performance, ACDR maintained index ROM and avoided compensation in adjacent ROM and tissue pressure.

CONCLUSIONS: Multilevel ACDR may be an effective and safe alternative to ACDF in terms of clinical and biomechanical performance. However, further multicenter and prospective studies should be conducted to obtain a stronger and more reliable conclusion.

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Impact of local steroid application on dysphagia following an anterior cervical discectomy and fusion: results of a prospective, randomized single-blind trial

J Neurosurg Spine 29:10–17, 2018

Intraoperative local steroid application has been theorized to reduce swelling and improve swallowing in the immediate period following anterior cervical discectomy and fusion (ACDF). Therefore, the purpose of this study was to quantify the impact of intraoperative local steroid application on patient-reported swallow function and swelling after ACDF.

METHODS A prospective, randomized single-blind controlled trial was conducted. A priori power analysis determined that 104 subjects were needed to detect an 8-point difference in the Quality of Life in Swallowing Disorders (SWAL-QOL) questionnaire score. One hundred four patients undergoing 1- to 3-level ACDF procedures for degenerative spinal pathology were randomized to Depo-Medrol (DEPO) or no Depo-Medrol (NODEPO) cohorts. Prior to surgical closure, patients received 1 ml of either Depo-Medrol (DEPO) or saline (NODEPO) applied to a Gelfoam carrier at the surgical site. Patients were blinded to the application of steroid or saline following surgery. The SWAL-QOL questionnaire was administered both pre- and postoperatively. A ratio of the prevertebral swelling distance to the anteroposterior diameter of each vertebral body level was calculated at the involved levels ± 1 level by using pre- and postoperative lateral radiographs. The ratios of all levels were averaged and multiplied by 100 to obtain a swelling index. An air index was calculated in the same manner but using the tracheal air window diameter in place of the prevertebral swelling distance. Statistical analysis was performed using the Student t-test and chi-square analysis. Statistical significance was set at p < 0.05.

RESULTS Of the 104 patients, 55 (52.9%) were randomized to the DEPO cohort and 49 (47.1%) to the NODEPO group. No differences in baseline patient demographics or preoperative characteristics were demonstrated between the two cohorts. Similarly, estimated blood loss and length of hospitalization did not differ between the cohorts. Neither was there a difference in the mean change in the scaled total SWAL-QOL score, swelling index, and air index between the groups at any time point. Furthermore, no complications were observed in either group (retropharyngeal abscess or esophageal perforation).

CONCLUSIONS The results of this prospective, randomized single-blind study did not demonstrate an impact of local intraoperative steroid application on patient-reported swallowing function or swelling following ACDF. Neither did the administration of Depo-Medrol lead to an earlier hospital discharge than that in the NODEPO cohort. These results suggest that intraoperative local steroid administration may not provide an additional benefit to patients undergoing ACDF procedures.

 

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What Is the Fate of Pseudarthrosis Detected 1 Year After Anterior Cervical Discectomy and Fusion?

Spine 2018;43:E23–E28

Objective. To investigate the consequences and appropriate management of pseudarthrosis after anterior cervical discectomy and fusion (ACDF).

Summary of Background Data. Pseudarthrosis is a frequent complication of ACDF and causes unsatisfactory results. Little is known about long-term prognosis of detecting pseudarthrosis 1 year after ACDF.

Methods. Eighty-nine patients with a minimum 2-year followup were included. ACDF surgery using allograft and plating was performed: single-level in 51 patients, two-level in 26 patients, and three-level in 12 patients. Presence of pseudarthrosis was evaluated 1 year postoperatively and then the nonunion segments were re-evaluated 2 years postoperatively. Demographic data were assessed to identify the risk factors associated with pseudarthrosis. A visual analogue scale for neck/arm pain and the Neck Disability Index were analyzed preoperatively and at 1 and 2 years postoperatively.

Results. Pseudarthrosis was detected in 29 patients (32.6%) 1 year postoperatively: 15of 51 patients after single-level surgery, 9 of 26 patients after two-level surgery, and 5 of 12 patients after three-level surgery. Only eight patients showed persistent nonunion at 2 years: 3 of 15 patients after single-level surgery, 3 of 9 after two-level surgery, and 2 of 5 after three-level surgery. The remaining 21 patients (72.4%) achieved bony fusion 2 years postoperatively without any intervention. Patients who underwent two-level or three-level ACDF had a significantly higher pseudarthrosis rate than those who underwent single-level ACDF, with odds ratios of 1.844 and 3.147, respectively. The improvements in visual analogue scale for neck pain and Neck Disability Index scores in the persistent nonunion group were significantly lower than those in the final union group at 2 years.

Conclusion. Patients with pseudarthrosis detected 1 year postoperatively may be observed without any intervention because approximately 70% of them will eventually fuse by the 2-year point. Early revision could, however, be considered if the pseudarthrosis is associated with considerable neck pain after multilevel ACDF.

Level of Evidence: 3

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Predictors for Patient Discharge Destination After Elective Anterior Cervical Discectomy and Fusion

Spine 2017;42:1538–1544

Study Design. Retrospective study of prospectively collected data.

Objective. To identify risk factors for nonhome patient discharge after elective anterior cervical discectomy and fusion (ACDF).

Summary of Background Data. ACDF is one of the most performed spinal procedures and this is expected to increase in the coming years. To effectively deal with an increasing patient volume, identifying variables associated with patient discharge destination can expedite placement applications and subsequently reduce hospital length of stay.

Methods. The 2011 to 2014 ACS-NSQIP database was queried using Current Procedural Terminology (CPT) codes 22551 or 22554. Patients were divided into two cohorts based on discharge destination. Bivariate and multivariate logistic regression analyses were employed to identify predictors for patient discharge destination and extended hospital length of stay.

Results. A total of 14,602 patients met the inclusion criteria for the study of which 498 (3.4%) had nonhome discharge. Multivariate logistic regression found that Hispanic versus Black race/ ethnicity (odds ratio, OR¼0.21, 0.05–0.91, P¼0.037), American Indian or Alaska Native, Asian, Native Hawaiian or Pacific Islander versus Black race/ethnicity (OR¼0.52, 0.34–0.80, p-value¼0.003), White versus Black race/ethnicity (OR¼0.55, 0.42–0.71), elderly age 65 years (OR¼3.32, 2.72–4.06), obesity (OR¼0.77, 0.63–0.93, P¼0.008), diabetes (OR¼1.32, 1.06–1.65, P¼0.013), independent versus partially/totally dependent functional status (OR¼0.11, 0.08–0.15), operation time 4hours (OR¼2.46, 1.87–3.25), cardiac comorbidity (OR ¼1.38, 1.10– 1.72, P ¼0.005), and ASA Class 3 (OR¼2.57, 2.05–3.20) were predictive factors in patient discharge to a facility other than home. In addition, multivariate logistic regression analysis also found nonhome discharge to be the most predictive variable in prolonged hospital length of stay.

Conclusion. Several predictive factors were identified in patient discharge to a facility other than home, many being preoperative variables. Identification of these factors can expedite patient discharge applications and potentially can reduce hospital stay, thereby reducing the risk of hospital acquired conditions and minimizing health care costs.

Level of Evidence: 3

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Cervical disc arthroplasty with the Prestige LP disc versus anterior cervical discectomy and fusion, at 2 levels: results of a prospective, multicenter randomized controlled clinical trial at 24 months

J Neurosurg Spine 26:653–667, 2017

The authors compared the efficacy and safety of arthroplasty using the Prestige LP cervical disc with those of anterior cervical discectomy and fusion (ACDF) for the treatment of degenerative disc disease (DDD) at 2 adjacent levels.

METHODS Patients from 30 investigational sites were randomized to 1 of 2 groups: investigational patients (209) underwent arthroplasty using a Prestige LP artificial disc, and control patients (188) underwent ACDF with a cortical ring allograft and anterior cervical plate. Patients were evaluated preoperatively, intraoperatively, and at 1.5, 3, 6, 12, and 24 months postoperatively. Efficacy and safety outcomes were measured according to the Neck Disability Index (NDI), Numeric Rating Scales for neck and arm pain, 36-Item Short-Form Health Survey (SF-36), gait abnormality, disc height, range of motion (investigational) or fusion (control), adverse events (AEs), additional surgeries, and neurological status. Treatment was considered an overall success when all 4 of the following criteria were met: 1) NDI score improvement of ≥ 15 points over the preoperative score, 2) maintenance or improvement in neurological status compared with preoperatively, 3) no serious AE caused by the implant or by the implant and surgical procedure, and 4) no additional surgery (supplemental fixation, revision, or nonelective implant removal). Independent statisticians performed Bayesian statistical analyses.

RESULTS The 24-month rates of overall success were 81.4% for the investigational group and 69.4% for the control group. The posterior mean for overall success in the investigational group exceeded that in the control group by 0.112 (95% highest posterior density interval = 0.023 to 0.201) with a posterior probability of 1 for noninferiority and 0.993 for superiority, demonstrating the superiority of the investigational group for overall success. Noninferiority of the investigational group was demonstrated for all individual components of overall success and individual effectiveness end points, except for the SF-36 Mental Component Summary. The investigational group was superior to the control group for NDI success. The proportion of patients experiencing any AE was 93.3% (195/209) in the investigational group and 92.0% (173/188) in the control group, which were not statistically different. The rate of patients who reported any serious AE (Grade 3 or 4) was significantly higher in the control group (90 [47.9%] of 188) than in the investigational group (72 [34.4%] of 209) with a posterior probability of superiority of 0.996. Radiographic success was achieved in 51.0% (100/196) of the investigational patients (maintenance of motion without evidence of bridging bone) and 82.1% (119/145) of the control patients (fusion). At 24 months, heterotopic ossification was identified in 27.8% (55/198) of the superior levels and 36.4% (72/198) of the inferior levels of investigational patients.

CONCLUSIONS Arthroplasty with the Prestige LP cervical disc is as effective and safe as ACDF for the treatment of cervical DDD at 2 contiguous levels and is an alternative treatment for intractable radiculopathy or myelopathy at 2 adjacent levels.

Clinical trial registration no.: NCT00637156 (clinicaltrials.gov)

 

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Cervical radiographic parameters in 1- and 2-level anterior cervical discectomy and fusion

cervical-radiographic-parameters-in-1-and-2-level-anterior-cervical-discectomy-and-fusion

J Neurosurg Spine 25:421–429, 2016

Anterior cervical discectomy and fusion (ACDF) is one of the most commonly performed spine procedures. It can be used to correct cervical kyphotic deformity, which is the most common cervical deformity, and is often performed using lordotic interbody devices. Worsening of the cervical sagittal parameters is associated with decreased health-related quality of life. The study hypothesis is that through the use of machined lordotic allografts in ACDF, segmental and overall cervical lordosis can be maintained or increased, which will have a positive impact on overall cervical sagittal alignment.

Methods: Seventy-four cases of 1-level ACDF (ACDF1) and 2-level ACDF (ACDF2) (40 ACDF1 and 34 ACDF2 procedures) were retrospectively reviewed. Upright neutral lateral radiographs were assessed preoperatively and at 6 weeks and 1 year postoperatively. The measured radiographic parameters included focal lordosis, disc height, C2–7 lordosis, C1–7 lordosis, T-1 slope, and C2–7 sagittal vertical axis. Correlation coefficients were calculated to determine the relationships between these radiographic measurements.

Results: The mean values were as follows: preoperative focal lordosis was 0.574°, disc height was 4.48 mm, C2–7 lordosis was 9.66°, C1–7 lordosis was 42.5°, cervical sagittal vertebral axis (SVA) was 26.9 mm, and the T-1 slope was 33.2°. Cervical segmental lordosis significantly increased by 6.31° at 6 weeks and 6.45° at 1 year. C2–7 lordosis significantly improved by 1 year with a mean improvement of 3.46°. There was a significant positive correlation between the improvement in segmental lordosis and overall cervical lordosis. Overall cervical lordosis was significantly negatively correlated with cervical SVA. Improved segmental lordosis was not correlated with cervical SVA in ACDF1 patients but was significantly negatively correlated in ACDF2 patients. There was also a significant positive correlation between the T-1 slope and cervical SVA.

Conclusions In the study population, the improvement of focal lordosis was significantly correlated with an improvement in overall lordosis (C1–7 and C2–7), and overall lordosis as measured by the C2–7 Cobb angle was significantly negatively correlated with cervical SVA. Using lordotic cervical allografts, we successfully created and maintained significant improvement in cervical segmental lordosis at the 6-week and 1-year time points with values of 6.31° and 6.45°, respectively. ACDF is able to achieve statistically significant improvement in C2–7 cervical lordosis by the 1-year followup, with a mean improvement of 3.46°. Increasing the number of levels operated on resulted in improved cervical sagittal parameters. This establishes a baseline for further examination into the ability of multilevel ACDF to achieve cervical deformity correction through the intervertebral correction of lordosis.

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Cervical disc arthroplasty with PRESTIGE LP disc versus anterior cervical discectomy and fusion

Cervical disc arthroplasty with PRESTIGE LP disc versus anterior cervical discectomy and fusion

J Neurosurg Spine 23:558–573, 2015

This study compared the safety and efficacy of treatment with the PRESTIGE LP cervical disc versus a historical control anterior cervical discectomy and fusion (ACDF).

METHODS Prospectively collected PRESTIGE LP data from 20 investigational sites were compared with data from 265 historical control ACDF patients in the initial PRESTIGE Cervical Disc IDE study. The 280 investigational patients with single-level cervical disc disease with radiculopathy and/or myelopathy underwent arthroplasty with a low-profile artificial disc. Key safety/efficacy outcomes included Neck Disability Index (NDI), Neck and Arm Pain Numerical Rating Scale scores, 36-Item Short Form Health Survey (SF-36) score, work status, disc height, range of motion, adverse events (AEs), additional surgeries, and neurological status. Clinical and radiographic evaluations were completed preoperatively, intraoperatively, and at 1.5, 3, 6, 12, and 24 months postoperatively. Predefined Bayesian statistical methods with noninformative priors were used, along with the propensity score technique for controlling confounding factors. Analysis by independent statisticians confirmed initial statistical findings.

RESULTS The investigational and control groups were mostly similar demographically. There was no significant difference in blood loss (51.0 ml [investigational] vs 57.1 ml [control]) or hospital stay (0.98 days [investigational] vs 0.95 days [control]). The investigational group had a significantly longer operative time (1.49 hours vs 1.38 hours); 95% Bayesian credible interval of the difference was 0.01–0.21 hours. Significant improvements versus preoperative in NDI, neck/arm pain, SF-36, and neurological status were achieved by 1.5 months in both groups and were sustained at 24 months. Patient follow-up at 24 months was 97.1% for the investigational group and 84.0% for the control group. The mean NDI score improvements versus preoperative exceeded 30 points in both groups at 12 and 24 months. SF-36 Mental Component Summary superiority was established (Bayesian probability 0.993). The mean SF-36 PCS scores improved by 14.3 points in the investigational group and by 11.9 points in the control group from baseline to 24 months postoperatively. Neurological success at 24 months was 93.5% in the investigational group and 83.5% in the control group (probability of superiority ~ 1.00). At 24 months, 12.1% of investigational and 15.5% of control patients had an AE classified as device or device/surgical procedure related; 14 (5.0%) investigational and 21 (7.9%) control patients had a second surgery at the index level. The median return-to-work time for the investigational group was 40 days compared with 60 days for the control group (p = 0.020 after adjusting for preoperative work status and propensity score). Following implantation of the PRESTIGE LP device, the mean angular motion was maintained at 12 months (7.9°) and 24 months (7.5°). At 24 months, 90.0% of investigational and 87.7% of control patients were satisfied with the results of surgery. PRESTIGE LP superiority on overall success (without disc height success), a composite safety/efficacy end point, was strongly supported with 0.994 Bayesian probability.

CONCLUSIONS This device maintains mean postoperative segmental motion while providing the potential for biomechanical stability. Investigational patients reported significantly improved clinical outcomes compared with baseline, at least noninferior to ACDF, up to 24 months after surgery.

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Adjacent Segment Disease After Anterior Cervical Discectomy and Fusion in a Large Series

ASD1

Neurosurgery 74:139–146, 2014

Adjacent segment disease (ASD) development is known to occur after anterior cervical discectomy and fusion (ACDF).

OBJECTIVE: To study the relationship between index ACDF levels and the location of ASD development (above/below), as well as the effect of fusion length on ASD development.

METHODS: We report 888 patients who underwent ACDF for cervical spondylosis over a twenty-year period at a single institution. Of these patients, 108 had re-do surgery due to symptomatic ASD. Patients were followed for an average of 92.4 6 52.6 months after the index ACDF.

RESULTS: In agreement with previous ACDF case series, we found the highest rates of cervical spinal degenerative disease requiring surgery at C5/C6, followed by C6/C7. Interestingly, neither the inherent location of index ACDF nor the length of instrumented arthrodesis appeared to correlate with the propensity to develop ASD. However, patients were more likely to develop ASD above the index level of fusion. This was true even for patients undergoing a second revision surgery due to recurrent ASD. Importantly, our data are consistent with existing in vitro biomechanical data in cadaveric spines.

CONCLUSION: We describe in detail the location and length of arthrodesis for index ACDFs, as well as first and second revision fusion surgeries in one of the largest Western cohorts in the literature. Our findings support the theory that iatrogenically introduced stress and instability at adjacent spinal segments contribute to the pathogenesis of ASD.

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Cost-effectiveness analysis: comparing single-level cervical disc replacement and single-level anterior cervical discectomy and fusion

CDR

J Neurosurg Spine 19:546–554, 2013

In recent years, there has been increased interest in the use of cervical disc replacement (CDR) as an alternative to anterior cervical discectomy and fusion (ACDF). While ACDF is a proven intervention for patients with myelopathy or radiculopathy, it does have inherent limitations. Cervical disc replacement was designed to preserve motion, avoid the limitations of fusion, and theoretically allow for a quicker return to activity. A number of recently published systematic reviews and randomized controlled trials have demonstrated positive clinical results for CDR, but no studies have revealed which of the 2 treatment strategies is more cost-effective. The purpose of this study was to evaluate the cost-effectiveness of CDR and ACDF by using the power of decision analysis. Additionally, the authors aimed to identify the most critical factors affecting procedural cost and effectiveness and to define thresholds for durability and function to focus and guide future research.

Methods. The authors created a surgical decision model for the treatment of single-level cervical disc disease with associated radiculopathy. The literature was reviewed to identify possible outcomes and their likelihood following CDR and ACDF. Health state utility factors were determined from the literature and assigned to each possible outcome, and procedural effectiveness was expressed in units of quality-adjusted life years (QALYs). Using ICD-9 procedure codes and data from the Nationwide Inpatient Sample, the authors calculated the median cost of hospitalization by multiplying hospital charges by the hospital-specific cost-to-charge ratio. Gross physician costs were determined from the mean Medicare reimbursement for each current procedural terminology (CPT) code. Uncertainty as regards both cost and effectiveness numbers was assessed using sensitivity analysis.

Results. In the reference case, the model assumed a 20-year duration for the CDR prosthesis. Cervical disc replacement led to higher average QALYs gained at a lower cost to society if both strategies survived for 20 years ($3042/QALY for CDR vs $8760/QALY for ACDF). Sensitivity analysis revealed that CDR needed to survive at least 9.75 years to be considered a more cost-effective strategy than ACDF. Cervical disc replacement becomes an acceptable societal strategy as the prosthesis survival time approaches 11 years and the $50,000/QALY gained willingness-to-pay threshold is crossed. Sensitivity analysis also indicated that CDR must provide a utility state of at least 0.796 to be cost-effective.

Conclusions. Both CDR and ACDF were shown to be cost-effective procedures in the reference case. Results of the sensitivity analysis indicated that CDR must remain functional for at least 14 years to establish greater costeffectiveness than ACDF. Since the current literature has yet to demonstrate with certainty the actual durability and long-term functionality of CDR, future long-term studies are required to validate the present analysis.

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Outcomes After Anterior Cervical Discectomy and Fusion in Professional Athletes

Outcomes After Anterior Cervical Discectomy and Fusion in Professional Athletes

Neurosurgery 73:103–112, 2013

Significant controversy exists regarding when an athlete may return to contact sports after anterior cervical discectomy and fusion (ACDF). Return-to-play (RTP) recommendations are complicated due to a mix of medical factors, social pressures, and limited outcome data.

OBJECTIVE: The aim of this study was to characterize our diagnostic and surgical criteria, intervention, postoperative imaging results, and rehabilitation and report RTP decisions and outcomes for professional athletes with cervical spine injuries.

METHODS: Fifteen professional athletes who had undergone a 1-level ACDF by a single neurosurgeon were identified after a retrospective chart and radiographic review from 2003 to 2012. Patient records and imaging studies were recorded.

RESULTS: Seven of the 15 athletes presented with neurapraxia, 8 with cervical radiculopathy, and 2 with hyperintensity of the spinal cord. Cervical stenosis with effacement of the cerebrospinal fluid signal was noted in 14 subjects. The operative level included C3-4 (4 patients), C4-5 (1 patient), C5-6 (8 patients), and C6-7 (2 patients). All athletes were cleared for RTP after a neurological examination with normal findings, and radiographic criteria for early fusion were confirmed. Thirteen of the 15 players returned to their sport between 2 and 12 months postoperatively (mean, 6 months), with 8 still participating. The RTP duration of the 5 who retired after full participation ranged from 1 to 3 years. All athletes remain asymptomatic for radicular or myelopathic symptoms or signs.

CONCLUSION: After a single-level ACDF, an athlete may return to contact sports if there are normal findings on a neurological examination, full range of neck movement, and solid arthrodesis. There may be an increased risk of the development of adjacent segment disease above or below the level of fusion. Cord hyperintensity may not necessarily preclude RTP.

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Comparison of 3 Reconstructive Techniques in the Surgical Management of Multilevel Cervical Spondylotic Myelopathy

Spine 2012 ; 37 : E1450 – E1458

A retrospective comparative study was performed in patients with 3-level cervical spondylotic myelopathy (CSM).

Objective. To compare the clinical outcomes, radiological parameters, and complication incidence of 3 reconstructive techniques after the anterior decompression of multilevel CSM.

Summary of Background Data. There has been growing interest in combination of anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF) for the treatment of multilevel CSM in recent years. However, the clinical efficacy and radiological outcomes of the hybrid decompression and fusion (HDF) have rarely been investigated.

Methods. A total of 180 consecutive patients with 3-level CSM undergoing the anterior decompression and fusion procedures from January 2003 to July 2010 were retrospectively investigated. According to various reconstructive techniques, the patients were divided into 3 groups: HDF, ACDF, and ACCF groups. The clinical effects and improvements of cervical and segmental lordosis in each group were assessed. In addition, the fusion rate, postoperative complications, and radiographical adjacent-level changes regarding each group were also evaluated.

Results. No statistical differences in clinical effects, restoration of cervical lordosis, and incidences of postoperative complications were found between the HDF and ACDF groups ( P > 0.05). The ACCF group has achieved clinical effects similar to the ACDF or HDF group ( P > 0.05), but it had more bleeding, lower fusion rate, and higher incidences of postoperative complications compared with the ACDF or HDF group ( P < 0.05). The improvements of the cervical and segmental lordosis in the ACCF group were significantly less than the ACDF or HDF group ( P < 0.05). There was no significant difference in radiographical adjacent-level changes among the 3 groups ( P > 0.05).

Conclusion. The HDF can be considered an effective and safe alternative procedure compared with ACDF in the treatment of the multilevel CSM, and ACCF should be the last option.

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Analysis of three IDE cervical arthroplasty trials

J Neurosurg Spine 16:216–228, 2012. DOI: 10.3171/2011.6.SPINE10623

There are now 3 randomized, multicenter, US FDA investigational device exemption, industry-sponsored studies comparing arthroplasty with anterior cervical discectomy and fusion (ACDF) for single-level cervical disease with 2 years of follow-up. These 3 studies evaluated the Prestige ST, Bryan, and ProDisc-C artificial discs. The authors analyzed the combined results of these trials.

Methods. A total of 1213 patients with symptomatic, single-level cervical disc disease were randomized into 2 treatment arms in the 3 randomized trials. Six hundred twenty-one patients received an artificial cervical disc, and 592 patients were treated with ACDF. In the three trials, 94% of the arthroplasty group and 87% of the ACDF group have completed 2 years of follow-up. The authors analyzed the 2-year data from these 3 trials including previously unpublished source data. Statistical analysis was performed with fixed and random effects models.

Results. The authors’ analysis revealed that segmental sagittal motion was preserved with arthroplasty (preoperatively 7.26° and postoperatively 8.14°) at the 2-year time point. The fusion rate for ACDF at 2 years was 95%. The Neck Disability Index, 36-Item Short Form Health Survey Mental, and Physical Component Summaries, neck pain, and arm pain scores were not statistically different between the groups at the 24-month follow-up. The arthroplasty group demonstrated superior results at 24 months in neurological success (RR 0.595, I2 = 0%, p = 0.006). The arthroplasty group had a lower rate of secondary surgeries at the 2-year time point (RR 0.44, I2 = 0%, p = 0.004). At the 2-year time point, the reoperation rate for adjacent-level disease was lower for the arthroplasty group when the authors analyzed the combined data set using a fixed effects model (RR 0.460, I2 = 2.9%, p = 0.030), but this finding was not significant using a random effects model. Adverse event reporting was too heterogeneous between the 3 trials to combine for analysis.

Conclusions. Both anterior cervical discectomy and fusion as well as arthroplasty demonstrate excellent 2-year surgical results for the treatment of 1-level cervical disc disease with radiculopathy. Arthroplasty is associated with a lower rate of secondary surgery and a higher rate of neurological success at 2 years. Arthroplasty may be associated with a lower rate of adjacent-level disease at 2 years, but further follow-up and analysis are needed to confirm this finding.

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