High Rate of Revision Surgery After Limited Decompression of Lumbar Facet Cysts.

INTRODUCTION: The surgical treatment of lumbar facet cysts has long been debated. Some surgeons elect for limited decompression of such cysts while other surgeons elect for primary decompression and fusion over concerns for recurrence and instability. Previous studies have suggested the rate of revision surgery after facet cyst excision to be as low as 1%, whereas others have reported this rate to be markedly higher. In this study, we examined revision surgery rates and patient-reported outcomes and conducted a radiographic analysis to identify predictors of failure after limited decompression of lumbar facet cysts. METHODS: A retrospective review of the electronic medical records of patients treated at our institution using the Current Procedural Terminology code 63267 before January 2018 was conducted. The primary outcome measure was revision surgery at the index level for recurrence or instability or a minimum 2-year follow-up without revision surgery. Secondary outcome measures include radiographic assessments of preoperative and postoperative spondylolisthesis and patient-reported outcome measures. Using preoperative MRI studies, an analysis of facet angles at the surgical level was conducted and the presence, location, and amount of facet fluid were calculated. RESULTS: A total of 162 patients met inclusion criteria. Of these, 93 patients had a minimum 2-year follow-up. Of these, 19 had undergone a revision surgery at the index level for cyst recurrence or instability. The revision rate for this group was 20.4%. The median time to initial revision surgery was 2.2 years. The median time from index operation to last follow-up was 3.8 years. No differences were observed between the groups regarding the presence of preoperative spondylolisthesis, age, sex, body mass index, blood loss, or patient demographics. 60.2% of all procedures were done at the L4-5 level, but this level accounted for 73.7% of primary failures. A radiographic analysis showed facet angle >45° at L4-5 to be associated with risk of failure of primary decompression. The presence and absolute amount of fluid in the facets were not associated with risk of failure at the L4-5 level. DISCUSSION: Our revision rate of 20.4% is higher than what is commonly reported in the literature. The radiographic analysis shows that at the L4-5 level, a facet angle of >45° is associated with failure of primary decompression.

Segmental Motion of Cervical Arthroplasty Leads to Decreased Adjacent-Level Degeneration: Analysis of the 7-Year Postoperative Results of a Multicenter Randomized Controlled Trial.

BACKGROUND: Cervical artificial disc replacement (C-ADR) has become a common and accepted surgical treatment for many patients with cervical disc degeneration/herniation and radiculopathy who have failed nonoperative treatment. Midterm follow-up studies of the original investigational device exemption trials comparing C-ADR to traditional anterior cervical discectomy and fusion (ACDF) have revealed C-ADR patients have less adjacent-level disease and fewer reoperations at 5 to 7 years. The purpose of this study was to examine the relationship of radiographic adjacent-level disease (R-ALD) with the amount of index-level segmental range of motion (ROM) in C-ADR patients using the long-term follow-up data from the ProDisc-C investigational device exemption trial. METHODS: This was a post hoc analysis of a 1:1 randomized controlled trial. The initial previously described Food and Drug Administration-approved 2-year study was extended, and consenting patients in the original study were followed at annual intervals up to 7 years. Logistic regression was used to assess any progression in adjacent-level disease (ALD). Ordinal logistic regression was also used to assess the relationship between any progressive R-ALD and final flexion extension (F/E) ROM in C-ADR patients. Spearman's rank-order correlation was used when R-ALD was kept as an ordinal variable to assess the same relationship. RESULTS: At the last follow-up visit, the rate of progressive R-ALD was significantly higher in ACDF patients than in C-ADR patients. When C-ADR patients were divided into 3 groups based on final F/E ROM, those with 0° to 3° (n = 19), 4° to 6° (n = 15), and 7° (n = 42) of segmental motion at the index procedure level, the rate of progressive R-ALD trended significantly with final ROM (P = 0.01). CONCLUSIONS: C-ADR leads to a significant decrease in R-ALD compared to ACDF. The difference in R-ALD is related to the preservation of motion at the index level and resultant preservation of kinematics and forces across the adjacent disc space.

Frequency and Acceptability of Adverse Events After Anterior Cervical Discectomy and Fusion: A Survey Study From the Cervical Spine Research Society.

PURPOSE: Anterior cervical discectomy and fusion has a low but well-established profile of adverse events. The goal of this study was to gauge surgeon opinion regarding the frequency and acceptability of these events. METHODS: A 2-page survey was distributed to attendees at the 2015 Cervical Spine Research Society (CSRS) meeting. Respondents were asked to categorize 18 anterior cervical discectomy and fusion-related adverse events as either: "common and acceptable," "uncommon and acceptable," "uncommon and sometimes acceptable," or "uncommon and unacceptable." Results were compiled to generate the relative frequency of these responses for each complication. Responses for each complication event were also compared between respondents based on practice location (US vs. non-US), primary specialty (orthopedics vs. neurosurgery) and years in practice. RESULTS: Of 150 surveys distributed, 115 responses were received (76.7% response rate), with the majority of respondents found to be US-based (71.3%) orthopedic surgeons (82.6%). Wrong level surgery, esophageal injury, retained drain, and spinal cord injury were considered by most to be unacceptable and uncommon complications. Dysphagia and adjacent segment disease occurred most often, but were deemed acceptable complications. Although surgeon experience and primary specialty had little impact on responses, practice location was found to significantly influence responses for 12 of 18 complications, with non-US surgeons found to categorize events more toward the uncommon and unacceptable end of the spectrum as compared with US surgeons. CONCLUSIONS: These results serve to aid communication and transparency within the field of spine surgery, and will help to inform future quality improvement and best practice initiatives.

Reoperation Rates Following Open-Door Cervical Laminoplasty.

BACKGROUND: Laminoplasty is a safe and effective procedure for multilevel degenerative cervical stenosis causing myelopathy, that allows for motion preservation. The purpose of this study was to determine the reoperation rate and associated risk factors after cervical laminoplasty. METHODS: We present a retrospective consecutive series of patients who underwent a laminoplasty procedure between January 1, 2005, and October 31, 2012, and had a minimum 2-year follow-up. Demographic data were collected and operative records were reviewed to determine the cervical levels involved in the laminoplasty procedure, any concomitant procedures, and estimated blood loss. Clinical records were reviewed and telephone interviews were conducted on those patients with less than 2-year in-person follow-up. Patients requiring reoperations and the reason for the reoperations were determined, as well as the incidence of postoperative C5 palsy. RESULTS: A total of 222 of 266 patients (83%) with a minimum 2-year follow-up had an average follow-up of 4.97 years. Overall, 26 patients underwent 30 reoperations (13.5%). A total of 15 patients underwent 16 reoperations (7.2%) in the acute postoperative period for infection requiring at least 1 irrigation and debridement, hardware-related issues, or posterior cervical wound issues. A total of 13 patients had 14 reoperations (6.3%) outside of the acute postoperative period for the development of a new radiculopathy, recurrent myelopathy, neurologic symptoms with a kyphotic deformity, or a posttraumatic focal kyphotic deformity. Patients who had a concomitant laminectomy demonstrated a significantly (P = .03) higher reoperation rate than those who did not. There were no other statistically significant associations. The C5 palsy rate was 8.1% (18 of 222). CONCLUSIONS: Although the preserved motion following laminoplasty may allow for the development of new neurologic symptoms, the reoperation rate continues to compare favorably with laminectomy and fusion and remains a reasonable option for the surgical management of multilevel cervical stenosis causing myelopathy. LEVEL OF EVIDENCE: 4.

Five-Year Reoperation Rates of 2-Level Lumbar Total Disk Replacement Versus Fusion: Results of a Prospective, Randomized Clinical Trial.

STUDY DESIGN: Long-term analysis of prospective randomized clinical trial data. SUMMARY OF BACKGROUND DATA: Lumbar total disk replacement (TDR) has been found to have equivalent or superior clinical outcomes compared with fusion and decreased radiographic incidence of adjacent level degeneration in single-level cases. OBJECTIVE: The purpose of this particular analysis was to determine the incidence and risk factors for secondary surgery in patients treated with TDR or circumferential fusion at 2 contiguous levels of the lumbar spine. METHODS: A total of 229 patients were treated and randomized to receive either TDR or circumferential fusion to treat degenerative disk disease at 2 contiguous levels between L3 and S1 (TDR, n=161; fusion, n=68). RESULTS: Overall, at final 5-year follow-up, 9.6% of subjects underwent a secondary surgery in this study. The overall rate of adjacent segment disease was 3.5% (8/229). At 5 years, the percentage of subjects undergoing secondary surgeries was significantly lower in the TDR group versus fusion (5.6% vs. 19.1%, P=0.0027).Most secondary surgeries (65%, 17/26) occurred at the index levels. Index level secondary surgeries were most common in the fusion cohort (16.2%, 11/68 subjects) versus TDR (3.1%, 5/161 subjects, P=0.0009). There no statistically significant difference in the adjacent level reoperation rate between TDR (2.5%, 4/161) and fusion (5.9%, 4/68). The most common reason for index levels reoperation was instrumentation removal (n=9). Excluding the instrumentation removals, there was not a significant difference between the treatments in index level reoperations or in reoperations overall. CONCLUSIONS: There were significantly fewer reoperations in TDR patients compared with fusion patients. However, most of the secondary surgeries were instrumentation removal in the fusion cohort. Discounting the instrumentation removals, there was no significant difference in reoperations between TDR and fusion. These results are indicative that lumbar TDR is noninferior to fusion.

The Prediction and Prevention of Dysphagia After Occipitospinal Fusion by Use of the S-line (Swallowing Line).

STUDY DESIGN: Clinical case series and risk factor analysis of dysphagia after occipitospinal fusion (OSF). OBJECTIVE: The aim of this study was to develop new criteria to avoid postoperative dysphagia by analyzing the relationship among the craniocervical alignment, the oropharyngeal space, and the incidence of dysphagia after OSF. SUMMARY OF BACKGROUND DATA: Craniocervical malalignment after OSF is considered to be one of the primary triggers of postoperative dysphagia. However, ideal craniocervical alignment has not been confirmed. METHODS: Thirty-eight patients were included. We measured the O-C2 angle (O-C2A) and the pharyngeal inlet angle (PIA) on the lateral cervical radiogram at follow-up. PIA is defined as the angle between McGregor's line and the line that links the center of the C1 anterior arch and the apex of cervical sagittal curvature. The impact of these two parameters on the diameter of pharyngeal airway space (PAS) and the incidence of the dysphagia were analyzed. RESULTS: Six of 38 cases (15.8%) exhibited the dysphagia. A multiple regression analysis showed that PIA was significantly correlated with PAS (ß = 0.714, P = 0.005). Receiver-operating characteristic curves showed that PIA had a high accuracy as a predictor of the dysphagia with an AUC (area under the curve) of 0.90. Cases with a PIA less than 90 degrees showed significantly higher incidence of dysphagia (31.6%) than those with a 90 or more degrees of PIA (0.0%) (P = 0.008). CONCLUSION: Our results indicated that PIA had the high possibility to predict postoperative dysphagia by OSF with the condition of PIA <90°. Based on these results, we defined "Swallowing-line (S-line)" for the reference of 90° of PIA. S-line (-) is defined as PIA <90°, where the apex of cervical lordosis protruded anterior to the "S-line," which should indicate the patient is at a risk of postoperative dysphagia. LEVEL OF EVIDENCE: 4.

Accuracy of a dynamic surgical guidance probe for screw insertion in the cervical spine: a cadaveric study.

STUDY DESIGN: A fresh frozen cadaver study was conducted. OBJECTIVE: To report the cortical breach rate using the dynamic surgical guidance (DSG) probe versus traditional freehand technique for cervical lateral mass, cervical pedicle and cervical laminar screws. METHODS: Nine male fresh frozen cadaveric torsos were utilized for this study. Each investigator was assigned three specimens that were randomized by fixation point, side and order of technique for establishing a screw pilot hole. The technique for screw hole preparation utilized was either a DSG probe in the "on" mode or in the "off" mode using a freehand technique popularized by Lenke et al. Levels instrumented included C1 lateral mass, C2 pedicle screws and lamina screws, and C6-T1 pedicle screws. Fluoroscopy and other navigational assistance were not used for screw hole preparation or screw insertion. All specimens were CT imaged following insertion of all screws. A senior radiologist evaluated all scans and determined that a misplaced screw was a breach of ≥2 mm. RESULTS: A total of 104 drillings were performed, 52 with DSG and 52 without DSG There were 68 total pedicle drillings, 34 in each group. There were 18 drillings in the lamina and lateral mass. There was no significant difference between surgeons or between the left and right side. All breaches were in the pedicle, and none in the lamina or lateral mass. The breach rate for PG "on" was 6/68 = 8.96% (95% CI 3.69, 19.12%). The breach rate for PG "off" was 20/68 = 29.41% (95% CI 19.30, 41.87%). Of the 20 pedicle breaches in the non-DSG group, 7 were lateral and superior, 8 were lateral, 4 medial and 1 inferior. Of the six pedicle breaches in the DSG group, two were lateral/superior, two were lateral and two were medial in the pedicle. CONCLUSIONS: The dynamic surgical guidance probe is a safe tool to assist the surgeon with screw placement in the cervical spine. Additionally, the DSG potentially avoids the cumulative risks associated with fluoroscopy and provides real-time feedback to the surgeon allowing correction at the time of breach. Level of evidence Level IV.

Adjacent segment degeneration following ProDisc-C total disc replacement (TDR) and anterior cervical discectomy and fusion (ACDF): does surgeon bias effect radiographic interpretation?

PURPOSE: Many investigators have reported the financial conflicts of interest (COI), which could result in potential bias in the reporting of outcomes for patients undergoing total disc replacement (TDR) rather than anterior cervical discectomy and fusion (ACDF). This bias may be subconsciously introduced by the investigator in a non-blinded radiographic review. The purpose of this study was to determine if bias was present when a group of spine specialists rated adjacent segment degeneration (ASD) following cervical TDR or ACDF. METHODS: Potential bias in the assessment of ASD was evaluated through the reviews of cervical radiographs (pre- and 6 years post-operative) from patients participating in the ProDisc-C FDA trial (ProDisc-C IDE #G030059). The index level was blinded on all radiographs during the first review, but unblinded in the second. Five reviewers (a radiologist, two non-TDR surgeons, and two TDR surgeons), two of whom had a COI with the ProDisc-C trial sponsor, assessed ASD on a three point scale: yes, no, or unable to assess. Intra- and inter-rater reliabilities between all raters were assessed by the Kappa statistic. RESULTS: The intra-rater reliability between reviews was substantial, indicating little to no bias in assessing ASD development/progression. The Kappa statistics were 0.580 and 0.644 for the TDR surgeons (p < 0.0001), 0.718 and 0.572 for the non-TDR surgeons (p < 0.0001), and 0.642 for the radiologist (p < 0.0001). Inter-rater reliability for the blinded review ranged from 0.316 to 0.607 (p < 0.0001) and from 0.221 to 0.644 (p < 0.0001) for the unblinded review. CONCLUSIONS: The knowledge of the surgical procedure performed did not bias the assessment of ASD.

A RCT comparing 7-year clinical outcomes of one level symptomatic cervical disc disease (SCDD) following ProDisc-C total disc arthroplasty (TDA) versus anterior cervical discectomy and fusion (ACDF).

PURPOSE: The objective of this trial was to compare the safety and efficacy of TDA using the ProDisc-C implant to ACDF in patients with single-level SCDD between C3 and C7. METHODS: We report on the single-site results from a larger multicenter trial of 13 sites using an approved US Food and Drug Administration protocol (prospective, randomized controlled non-inferiority design). Patients were randomized one-to-one to either the ProDisc-C device or ACDF. All enrollees were evaluated pre- and post-operatively at regular intervals through month 84. Visual Analog Scale (VAS) for neck and arm pain/intensity, Neck Disability Index (NDI), Short-Form 36 (SF-36), and satisfaction were assessed. RESULTS: Twenty-two patients were randomized to each arm of the study. Nineteen additional patients received the ProDisc-C via continued access. NDI improved with the ProDisc-C more than with ACDF. Total range of motion was maintained with the ProDisc-C, but diminished with ACDF. Neck and arm pain improved more in the ProDisc-C than ACDF group. Patient satisfaction remained higher in the ProDisc-C group at 7 years. SF-36 scores were higher in the TDA group than ACDF group at 7 years; the difference was not clinically significant. Six additional operations (two at the same level; four at an adjacent level) were performed in the ACDF, but none in the ProDisc-C group. CONCLUSIONS: The ProDisc-C implant appears to be safe and effective for the treatment of SCDD. Patients with the implant retained motion at the involved segment and had a lower reoperation rate than those with an ACDF.

ProDisc-C Total Disc Replacement Versus Anterior Cervical Discectomy and Fusion for Single-Level Symptomatic Cervical Disc Disease: Seven-Year Follow-up of the Prospective Randomized U.S. Food and Drug Administration Investigational Device Exemption Study.

BACKGROUND: In patients with single-level cervical degenerative disc disease, total disc arthroplasty can relieve radicular pain and preserve functional motion between two vertebrae. We compared the efficacy and safety of cervical total disc arthroplasty with that of anterior cervical discectomy and fusion (ACDF) for the treatment of single-level cervical degenerative disc disease between C3-C4 and C6-C7. METHODS: Two hundred and nine patients at thirteen sites were randomly treated with either total disc arthroplasty with ProDisc-C (n = 103) or with ACDF (n = 106). Patients were assessed preoperatively; at six weeks and three, six, twelve, eighteen, and twenty-four months postoperatively; and then annually until seven years postoperatively. Outcome measures included the Neck Disability Index (NDI), the Short Form-36 (SF-36), postoperative neurologic parameters, secondary surgical procedures, adverse events, neck and arm pain, and satisfaction scores. RESULTS: At seven years, the overall follow-up rate was 92% (152 of 165). There were no significant differences in demographic factors, follow-up rate, or patient-reported outcomes between groups. Both procedures were effective in reducing neck and arm pain and improving and maintaining function and health-related quality of life. Neurologic status was improved or maintained in 88% and 89% of the patients in the ProDisc-C and ACDF groups, respectively. After seven years of follow-up, thirty secondary surgical procedures had been performed in nineteen (18%) of 106 patients in the ACDF group compared with seven secondary surgical procedures in seven (7%) of 103 patients in the ProDisc-C group (p = 0.0099). There were no significant differences in the rates of any device-related adverse events between the groups. CONCLUSIONS: Total disc arthroplasty with ProDisc-C is a safe and effective surgical treatment of single-level symptomatic cervical degenerative disc disease. Clinical outcomes after total disc arthroplasty with ProDisc-C were similar to those after ACDF. Patients treated with ProDisc-C had a lower probability of subsequent surgery, suggesting that total disc arthroplasty provides durable results and has the potential to slow the rate of adjacent-level disease. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Unintended durotomy in lumbar degenerative spinal surgery: a 10-year systematic review of the literature.

OBJECT Unintended durotomy is a common occurrence during lumbar spinal surgery, particularly in surgery for degenerative spinal conditions, with the reported incidence rate ranging from 0.3% to 35%. The authors performed a systematic literature review on unintended lumbar spine durotomy, specifically aiming to identify the incidence of durotomy during spinal surgery for lumbar degenerative conditions. In addition, the authors analyzed the incidence of durotomy when minimally invasive surgical approaches were used as compared with that following a traditional midline open approach. METHODS A MEDLINE search using the term "lumbar durotomy" (under the 2015 medical subject heading [MeSH] "cerebrospinal fluid leak") was conducted on May 13, 2015, for English-language medical literature published in the period from January 1, 2005, to May 13, 2015. The resulting papers were categorized into 3 groups: 1) those that evaluated unintended durotomy rates during open-approach lumbar spinal surgery, 2) those that evaluated unintended durotomy rates during minimally invasive spine surgery (MISS), and 3) those that evaluated durotomy rates in comparable cohorts undergoing MISS versus open-approach lumbar procedures for similar lumbar pathology. RESULTS The MEDLINE search yielded 116 results. A review of titles produced 22 potentially relevant studies that described open surgical procedures. After a thorough review of individual papers, 19 studies (comprising 15,965 patients) pertaining to durotomy rates during open-approach lumbar surgery were included for analysis. Using the Oxford Centre for Evidence-Based Medicine (CEBM) ranking criteria, there were 7 Level 3 prospective studies and 12 Level 4 retrospective studies. In addition, the authors also included 6 studies (with a total of 1334 patients) that detailed rates of durotomy during minimally invasive surgery for lumbar degenerative disease. In the MISS analysis, there were 2 prospective and 4 retrospective studies. Finally, the authors included 5 studies (with a total of 1364 patients) that directly compared durotomy rates during open-approach versus minimally invasive procedures. Studies of open-approach surgery for lumbar degenerative disease reported a total of 1031 durotomies across all procedures, for an overall durotomy rate of 8.11% (range 2%-20%). Prospectively designed studies reported a higher rate of durotomy than retrospective studies (9.57% vs 4.32%, p = 0.05). Selected MISS studies reported a total of 93 durotomies for a combined durotomy rate of 6.78%. In studies of matched cohorts comparing open-approach surgery with MISS, the durotomy rates were 7.20% (34 durotomies) and 7.02% (68), respectively, which were not significantly different. CONCLUSIONS Spinal surgery for lumbar degenerative disease carries a significant rate of unintended durotomy, regardless of the surgical approach selected by the surgeon. Interpretation of unintended durotomy rates for lumbar surgery is limited by a lack of prospective and cohort-matched controlled studies.

Mimickers of lumbar radiculopathy.

Orthopaedic surgeons frequently treat patients who report pain that radiates from the back into the lower extremity. Although the most common etiology is either a herniated disk or spinal stenosis, a myriad of pathologies can mimic the symptoms of radiculopathy, resulting in differences in the clinical presentation and the workup. Therefore, the clinician must be able to distinguish the signs and symptoms of lumbar radiculopathy from pathologies that may have a similar presentation. Being cognizant of these other possible conditions enables the physician to consider a breadth of alternative diagnoses when a patient presents with radiating lower extremity pain.

Timing of surgery in thoracolumbar trauma: is early intervention safe?

The understanding of the optimal surgical timing for stabilization in thoracolumbar fractures is severely limited. Thoracolumbar spine fractures can be devastating injuries and are often associated with significant morbidity and mortality. The role of early surgical stabilization (within 48-72 hours of injury) as a vehicle to improve outcomes in these patients has generated significant interest. Goals of early stabilization include improved neurological recovery, faster pulmonary recovery, improved pain control, and decreased health care costs. Opponents cite the potential for increased bleeding, hypotension, and the risk of further cord injury as a few factors that weigh against early stabilization. The concept of spinal cord injury and its relationship to surgical timing remains in question. However, when neurological outcomes are eliminated from the equation, certain measures have shown positive influences from prompt surgical fixation. Early fixation of thoracolumbar spine fractures can significantly decrease the duration of hospital stay and the number of days in the intensive care unit. Additionally, prompt stabilization can reduce rates of pulmonary complications. This includes decreased rates of pneumonia and fewer days on ventilator support. Cost analysis revealed as much as $80,000 in savings per patient with early stabilization. All of these benefits come without an increase in morbidity or evidence of increased mortality. In addition, there is no evidence that early stabilization has any ill effect on the injured or uninjured spinal cord. Based on the existing data, early fixation of thoracolumbar fractures has been linked with positive outcomes without clear evidence of negative impacts on the patient's neurological status, associated morbidities, or mortality. These procedures can be viewed as "damage control" and may consist of simple posterior instrumentation or open reductions with internal fixation as indicated. Based on the current literature it is advisable to proceed with early surgical stabilization of thoracolumbar fractures in a well-resuscitated patient, unless extenuating medical conditions would prevent it.

Single-center results at 7 years of prospective, randomized ProDisc-C total disc arthroplasty versus anterior cervical discectomy and fusion for treatment of one level symptomatic cervical disc disease.

Consistent with EBSJ's commitment to fostering quality research, we are pleased to feature some of the most highly rated abstracts from the 10th Annual AOSpine North America Fellows Forum in Banff, Canada. Enhancing the quality of evidence in spine care means acknowledging and supporting the efforts of young researchers within our AOSpine North America network. We look forward to seeing more from these promising researchers in the future.

Dural tears in spine surgery.

Dural tears are among the most commonly seen complications in spine surgery. Most studies in the literature indicate that long-term outcomes are not negatively affected, provided that the tears are diagnosed early and managed appropriately. Direct suture repair remains the preferred method for the management of durotomy caused by or found during surgery. However, recent literature reports encouraging results with sutureless repair. Understanding dural anatomy, dural healing, and cerebrospinal fluid dynamics is helpful in choosing among the available management options for dural tear.

Incidence of dysphagia comparing cervical arthroplasty and ACDF.

STUDY DESIGN: Retrospective cohort from randomized prospective clinical trial. OBJECTIVE: Evaluate incidence of dysphagia between instrumented ACDF and a no-profile cervical disc arthroplasty. SUMMARY OF BACKGROUND DATA: Dysphagia is a well-known complication following anterior cervical discectomy and fusion (ACDF) and the etiology is multifactorial. One potential source for postoperative dysphagia involves the anterior profile of the implant used. Hence, a no-profile cervical disc arthroplasty could theoretically have fewer soft tissue adhesions and a lower incidence of dysphagia. The purpose of this study is to compare the incidence of dysphagia at least 1 year postoperatively following ACDF with anterior plating and a no-profile cervical disc arthroplasty. METHODS: A cohort of 87 patients meeting the inclusion criteria for the prospective, randomized, multicenter IDE trial of ProDisc-C versus ACDF were evaluated for dysphagia. Forty-five patients were randomized to receive cervical arthroplasty and 42 patients were randomized to the ACDF and plate group. The Bazaz-Yoo dysphagia questionnaire was administered in a blinded fashion after completion of at least 12 months follow-up. RESULTS: Follow-up averaged 18.2 months and included 76 (87%) of the 87 enrolled, with 38 of the original 45 in the arthroplasty group and 38 of the original 42 in the ACDF group. Six of 38 (15.8%) in the arthroplasty group versus 16 of 38 (42.1%) in the ACDF group reported ongoing dysphagia complaints. This was found to be statistically significant (P = .03). CONCLUSION: This study suggests a significantly lower rate of dysphagia with a no-profile cervical disc arthroplasty compared to instrumented ACDF for single level disc disease between C3-7. Though there are many potential etiologies, we hypothesize this is related to the lack of anterior hardware in the retropharyngeal space. Operative technique, operating time, and significant midline retraction did not seem to result in more dysphagia complaints. Future studies comparing cervical disc arthroplasty and no-profile fusion devices may help delineate the effect that anterior instrumentation profile has on postoperative dysphagia.

Results at 24 months from the prospective, randomized, multicenter Investigational Device Exemption trial of ProDisc-C versus anterior cervical discectomy and fusion with 4-year follow-up and continued access patients.

BACKGROUND: Cervical total disk replacement (TDR) is intended to address pain and preserve motion between vertebral bodies in patients with symptomatic cervical disk disease. Two-year follow-up for the ProDisc-C (Synthes USA Products, LLC, West Chester, Pennsylvania) TDR clinical trial showed non-inferiority versus anterior cervical discectomy and fusion (ACDF), showing superiority in many clinical outcomes. We present the 4-year interim follow-up results. METHODS: Patients were randomized (1:1) to ProDisc-C (PDC-R) or ACDF. Patients were assessed preoperatively, and postoperatively at 6 weeks and 3, 6, 12, 18, 24, 36, and 48 months. After the randomized portion, continued access (CA) patients also underwent ProDisc-C implantation, with follow-up visits up to 24 months. Evaluations included Neck Disability Index (NDI), Visual Analog Scale (VAS) for pain/satisfaction, and radiographic and physical/neurologic examinations. RESULTS: Randomized patients (103 PDC-R and 106 ACDF) and 136 CA patients were treated at 13 sites. VAS pain and NDI score improvements from baseline were significant for all patients (P < .0001) but did not differ among groups. VAS satisfaction was higher at all time points for PDC-R versus ACDF patients (P = .0499 at 48 months). The percentage of patients who responded yes to surgery again was 85.6% at 24 months and 88.9% at 48 months in the PDC-R group, 80.9% at 24 months and 81.0% at 48 months in the ACDF group, and 86.3% at 24 months in the CA group. Five PDC-R patients (48 months) and no CA patients (24 months) had index-level bridging bone. By 48 months, approximately 4-fold more ACDF patients required secondary surgery (3 of 103 PDC-R patients [2.9%] vs 12 of 106 ACDF patients [11.3%], P = .0292). Of these, 6 ACDF patients (5.6%) required procedures at adjacent levels. Three CA patients required secondary procedures (24 months). CONCLUSIONS: Our 4-year data support that ProDisc-C TDR and ACDF are viable surgical options for symptomatic cervical disk disease. Although ACDF patients may be at higher risk for additional surgical intervention, patients in both groups show good clinical results at longer-term follow-up.