Clinical Adjacent Segment Pathology Research Articles

Research protocol: Cervical Arthroplasty Cost Effectiveness Study (CACES): economic evaluation of anterior cervical discectomy with arthroplasty (ACDA) versus anterior cervical discectomy with fusion (ACDF) in the surgical treatment of cervical degenerative disc disease — a randomized controlled trial

IntroductionTo date, there is no consensus on which anterior surgical technique is more cost-effective in treating cervical degenerative disc disease (CDDD). The most commonly used surgical treatment for patients with single- or multi-level symptomatic CDDD is anterior cervical discectomy with fusion (ACDF). However, new complaints of radiculopathy and/or myelopathy commonly develop at adjacent levels, also known as clinical adjacent segment pathology (CASP). The extent to which kinematics, surgery-induced fusion, natural history, and progression of disease play a role in the development of CASP remains unclear. Anterior cervical discectomy with arthroplasty (ACDA) is another treatment option that is thought to reduce the incidence of CASP by preserving motion in the operated segment. While ACDA is often discouraged, as the implant costs are higher while the clinical outcomes are similar to ACDF, preventing CASP might be a reason for ACDA to be a more cost-effective technique in the long term.Methods and analysisIn this randomized controlled trial, patients will be randomized to receive ACDF or ACDA in a 1:1 ratio. Adult patients with single- or multi-level CDDD and symptoms of radiculopathy and/or myelopathy will be included. The primary outcome is cost-effectiveness and cost-utility of both techniques from a healthcare and societal perspective. Secondary objectives are the differences in clinical and radiological outcomes between the two techniques, as well as the qualitative process surrounding anterior decompression surgery. All outcomes will be measured at baseline and every 6 months until 4 years post-surgery.DiscussionHigh-quality evidence regarding the cost-effectiveness of both ACDA and ACDF is lacking; to date, there are no prospective trials from a societal perspective. Considering the aging of the population and the rising healthcare costs, there is an urgent need for a solid clinical cost-effectiveness trial addressing this question.Trial registrationClinicalTrials.gov NCT04623593. Registered on 29 September 2020.

Clinical adjacent segment pathology after anterior cervical discectomy, with and without fusion, for cervical degenerative disc disease: A single center retrospective cohort study with long-term follow-up

IntroductionClinical adjacent segment pathology (CASP) continues to be a cause of concern after anterior surgical treatment for single- or multilevel cervical degenerative disc disease (CDDD). The current literature reports inconsistent incidence rates and contended risk factors in the development of CASP. Research questionThe aim is to determine the incidence of additional CASP-related surgeries after anterior cervical discectomy with fusion (ACDF) or without fusion (ACD) for CDDD. Secondary outcomes include risk factors for the development of CASP and long-term clinical outcomes. Materials & methodsThis is a single-center, retrospective cohort study with a long-term follow up. Patients undergoing ACD(F) for CDDD between January 2012 and December 2019 were included. ResultsA total of 601 patients were included, with an average follow-up period of 5.0 years. Most patients underwent ACDF with stand-alone cages (87.7%). CASP developed in 58 (9.7%) patients, 41 (70.7%) of which required additional adjacent level surgery. ACD significantly accelerated the development of CASP. The C2–C7 Cobb angle appeared less lordotic upon early post-operative imaging in ACDF patients that later-on developed CASP. Baseline degeneration at the index level and adjacent levels was not significantly different between patients with and without CASP. Discussion & conclusionIn this retrospective cohort, we observe a relatively low rate of additional surgery for CASP in ACDF with stand-alone cages. We suggest that surgical technique, fusion, segmental kyphosis and natural degeneration play a multifactorial role in the development of CASP. Complication rates were low and clinical outcomes were similar for all techniques used.

Comparison of Incidence of Adjacent Segment Pathology between Anterior Lumbar Interbody Fusion and Transforaminal Lumbar Interbody Fusion Treatments for Lumbosacral Junction.

This research compared the incidence of adjacent segment pathology (ASP) between anterior interbody lumbar fusion (ALIF) treatment and transforaminal lumbar interbody fusion (TLIF) treatment. Seventy patients were included in this retrospective study: 30 patients received ALIF treatment, and 40 patients received TLIF treatment at a single medical center between 2011 and 2020 with a follow-up of at least 12 months. The outcomes were radiographic adjacent segment pathology (RASP) and clinical adjacent segment pathology (CASP). The mean follow-up period was 42.10 ± 22.61 months in the ALIF group and 56.20 ± 29.91 months in the TLIF group. Following single-level lumbosacral fusion, ALIF is superior to TLIF in maintaining lumbar lordosis, whereas the risk of adjacent instability in the ALIF group is significantly higher. Regarding ASP, the incidence of overall RASP and CASP did not differ significantly between ALIF and TLIF groups.

Differences in the Prevalence of Clinical Adjacent Segment Pathology among Continents after Anterior Cervical Fusion: Meta-Analysis of Randomized Controlled Trials.

Development of adjacent segment pathology leading to secondary operation is a matter of concern after anterior cervical discectomy and fusion (ACDF). Some studies have reported anatomic difference between races, but no epidemiological data on prevalence of clinical adjacent segment pathology (cASP) among races or continents has been published. The purpose of this study was to compare the prevalence of cASP that underwent surgery after monosegmental ACDF among continents by meta-analysis. MEDLINE, EMBASE, and Cochrane Library with manual searching in key journals, reference lists, and the National Technical Information Service were searched from inception to December 2018. Twenty studies with a total of 2009 patients were included in the meta-analysis. We extracted the publication details, sample size, and prevalence of cASP that underwent surgery. A total of 15 papers from North America, three from Europe, and two from Asia met the inclusion criteria. A total number of 2009 patients underwent monosegmental ACDF, and 113 patients (5.62%) among them had cASP that underwent surgery. The rate of cASP that underwent surgery was 4.99% in the North America, 3.65% in the Europe, 6.34% in the Asia, and there were no statistically significant differences (p = 0.63). The current study using the method of meta-analysis revealed that there were no significant differences in the rate of cASP that underwent surgery after ACDF among the continents.

Clinical adjacent segment pathology after anterior cervical decompression surgery for cervical degenerative disc disease: a single center retrospective cohort study with long-term follow-up

Clinical adjacent segment pathology after anterior cervical decompression surgery for cervical degenerative disc disease: a single center retrospective cohort study with long-term follow-up

Reoperation for Proximal Adjacent Segment Pathology in Posterior Cervical Fusion Constructs that Fuse to C2 vs C3.

Few studies have described rates of proximal clinical adjacent segment pathology (CASP) after posterior cervical decompression and fusion (PCDF). To investigate rates of proximal CASP at C2 vs C3 in PCDFs for degenerative spine disease. A retrospective review of 380 cases of PCDF for degenerative disease with proximal constructs ending at C2 vs C3 was performed. Minimum follow-up was 12 mo. The primary outcome was proximal CASP requiring reoperation. Variable analysis included demographic, operative, and complication data. There were 119 patients in the C2 group and 261 in the C3 group with no significant differences in age, gender, comorbidities, presenting symptoms, or complications. Vertebral artery injury rates were 0.8% in the C2 group and 0.0% in the C3 group (P=.12). No patients in the C2 group had reoperation for proximal CASP, while 5.0% of patients in the C3 group did (P=.01). Patients with arthrodesis up to C3 had an increased risk of proximal failure when the fusion construct crossed the cervicothoracic junction (P=.03). Multivariate logistic regression analysis showed no factors that were independently associated with re-instrumentation for proximal CASP. Instrumenting to the C2 level reduces the risk for proximal CASP compared to fusion only up to C3. The type of instrumentation used at these 2 levels, form of ASP disease at C1-C2, and natural motion of the relevant proximal adjacent joint may contribute to this difference. Furthermore, within the C3 cohort, fusion across the cervicothoracic junction increased the risk for proximal CASP.

Risk factors associated with clinical adjacent segment pathology following multi-level cervical fusion surgery.

Few clinical studies investigate risk factors associated with clinical adjacent segment pathology (CASP) following multi-level cervical fusion surgery. The aim is to record the incidence of postoperative CASP in patients after at least 2 years′ follow-up and to identify possible risk factors that may be associated with the CASP after multi-level cervical surgery.We retrospectively reviewed patients who underwent multi-level cervical surgery in our hospital from January 2004 to February 2016. All patients underwent more than 2 years′ follow-up. The diagnosis of CASP is according to clinical symptoms as well as image findings. Potential risk factors were collected from demographic data and radiographic images.A total of 301 patients after multi-level cervical surgery were analyzed. During follow-up, 28 patients (9.3%) were diagnosed as having CASP. Among these patients, 7 showed symptoms of CASP within 3 years after surgery, 6 showed symptoms between 3 and 5 years, 14 showed symptoms between 5 and 10 years, and the last one showed symptoms more than 10 years later. In the multivariate analysis, degeneration of adjacent segment (OR, 1.592; 95% CI, 1.113–2.277), decreased Cobb angle in fused vertebrae (OR, 2.113; 95% CI, 1.338–3.334) and decreased Cobb angle in cervical spine (OR, 1.896; 95% CI, 1.246–2.886) were correlated with the incidence of CASP during follow-up.The incidence of CASP following multi-level cervical surgery was 9.3% with a mean of about 70 months′ follow-up. Patients with preoperative degeneration of adjacent segment and postoperative imbalance of sagittal alignment have a higher risk of developing CASP after multi-level cervical surgery.

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P115. Clinical adjacent segment pathology following treatment with CDA or ACDF at one or two-levels through seven-years

BACKGROUND CONTEXT Adjacent segment pathology (ASP) continues to be a concern for surgeons and patients following cervical spine surgery. Most reports to date have focused on either reoperation at the index level or reoperation at any level. There is little debate that radiographic ASP (rASP) favors cervical disc arthroplasty (CDA), but few studies have explored clinical ASP (cASP). PURPOSE To evaluate cASP in patients treated with CDA or ACDF. STUDY DESIGN/SETTING Post-hoc analyses were performed on data that was collected through 7years in a prospective, randomized, controlled clinical trial comparing CDA to ACDF with allograft and anterior plate at one or two contiguous levels. PATIENT SAMPLE The patient population consisted of 575 randomized patients: 164 one-level CDA and 81 one-level ACDF; 225 two-level CDA and 105 two-level ACDF. OUTCOME MEASURES Adjacent level surgeries through 7years. METHODS Kaplan-Meier survival curves for adjacent level surgery were compared using the log-rank test. Cox regression was used to assess the impact of treatment on the relative risk of adjacent level surgery. RESULTS Follow-up rates through 7years were 74.6%. The proportion of patients undergoing an adjacent level surgery was 14.8% for 1-level ACDF, 4.3% for 1-level CDA, 12.4% for 2-level ACDF, and 4.9% for two-level CDA. Kaplan–Meier survival estimates of the probability of adjacent level surgery heavily favored CDA over ACDF (p CONCLUSIONS The adjacent level surgery rates of ACDF patients are over three times higher than CDA at one-level and 2.5times for two-level through 7-years follow-up. In this patient population the survival estimates strongly favor CDA, with estimated rates of adjacent level surgery per 100 patients three times higher for ACDF (p

Survivorship Analysis of Clinical Adjacent-Segment Pathology After Single-Level Cervical Fusion.

BackgroundClinical adjacent-segment pathology (CASP) is an important problem after anterior cervical surgery. The purpose of this study was to predict prevalence of CASP and determine the possible risk factors for CASP after single-level anterior cervical discectomy and fusion surgery.Material/MethodsWe retrospectively reviewed a series of patients who underwent single-level cervical discectomy and fusion surgery (ACDF). Both basic and radiographic data of patients were collected. Life-table method and Kaplan-Meier analysis were used to calculate prevalence of CASP and disease-free survival rate. Cox analysis was performed to determine the predictive factors for it.ResultsA total of 256 patients were included in this study. The mean length of follow-up was 70.64 months. Among them, 31 patients were diagnosed as having CASP during follow-up. Nineteen of them were at the cephalad adjacent segment, and the other 12 were at the caudal segment. After ACDF procedures, 10.01% of patients developed new symptoms of CASP within 5 years, and the incidence increased to 23.89% after 10 years. The incidence rate of CASP was an average of 2.46% per year. Multivariate Cox regression analysis showed that congenital stenosis (hazard ratio [HR], 3.250; 95% confidence interval [CI], 1.538–6.867) and degeneration of adjacent segment (HR, 2.681; 95% CI, 1.259–5.709) were correlated with the incidence of CASP.ConclusionsPatients with congenital stenosis and pre-existing degenerative changes of adjacent segments had a higher risk of developing CASP after single-level anterior cervical discectomy and fusion.

Does the Addition of a Dynamic Pedicle Screw to a Fusion Segment Prevent Adjacent Segment Pathology in the Lumbar Spine?

Study DesignRetrospective clinical cohort study.Purpose To investigate whether the combined use of dynamic pedicle screws and polyaxial pedicle screws was effective on adjacent segment pathology (ASP).Overview of LiteratureVarious screw and rod models have been recently developed for preventing adjacent segment disease, and hybrid systems have been described along with posterior instrumentation in the fusion segment. In the literature, although the success of dynamic systems has been demonstrated in non-fusion posterior instrumentation, it remains unclear whether the addition of a screw-based dynamic system to a fusion segment would successfully prevent ASP in the long term.MethodsThe study included 101 patients who underwent surgery for degenerative spine diseases between 2007 and 2014 with lumbar stabilization that used either polyaxial pedicle screws alone or polyaxial pedicle screws plus dynamic stabilization screws (with hinged screw heads). These two patient groups were compared using retrospectively obtained postoperative new clinical findings, Oswestry disability index (ODI) scores, visual analog scale (VAS) scores, and radiological data.ResultsThe proportion of patients with ASP who were radiologically assessed was low (p <0.01) in the group that underwent lumbar stabilization along with dynamic screws. Treatment outcomes were clinically successful in both groups according to ODI and VAS scores, and no significant difference was determined between the groups in terms of clinical ASP (p >0.05).ConclusionsAlthough the combined use of dynamic screws and the static system was radiologically found to be effective for preventing ASP in patients who underwent lumbar fusion with posterior instrumentation, it did not completely eliminate ASP or result in a significant improvement in clinical ASP.

Adjacent level disease-background and update based on disc replacement data.

The precise etiology of adjacent segment disease following cervical spine surgery is controversial. Theories for development include inevitable changes secondary to the natural progression of the degenerative cascade and changes secondary to altered biomechanics of the fused cervical spine. Motion preserving techniques, such as cervical disc arthroplasties (CDA), have been introduced with the hopes of reducing the rates of adjacent segment pathology. Recently, 7-year data from the investigational device exemption (IDE) studies have been published. The purpose of this review is to provide an update on cervical adjacent segment disease incorporating this emerging data into the analysis. Although the 7-year data for CDA has confirmed continued success, specifically regarding improved neck pain and reduced re-operation rates, the influence of CDA on reducing rates of adjacent segment pathology remains questionable. Although some studies have found more radiographic adjacent segment disease after anterior cervical discectomy and fusion (ACDF) compared to CDA, an association between these findings and clinical symptoms has not been established. Cervical disc arthroplasty continues to outperform cervical disc fusion regarding some patient specific parameters, however, whether CDA reduces rates of radiographic and clinical adjacent segment pathology remains unknown. Without studies developed specifically to address this question, the answer remains elusive.

Adjacent Segment Pathology: Progressive Disease Course or a Product of Iatrogenic Fusion?

Cervical spine clinical adjacent segment pathology (CASP) has a reported 3% annual incidence and 26% ten-year prevalence. Its pathophysiology remains controversial, whether due to mechanical stress of a fusion segment on adjacent levels or due to patient propensity to develop progressive degenerative change. We investigate this relationship by comparing prevalence of CASP in traumatic and spondylotic patient cohorts. A retrospective review of traumatic cervical spine fusion cases performed by the local group of neurosurgeons from 2004-2008 was completed. Surgery for CASP and presence of radiological adjacent segment pathology (RASP) were identified by telephone and electronic medical record (EMR) review, and compared to those in patients having elective cervical fusion for degenerative disease. There was a higher proportion of males (50/100 vs. 37/46, p0.05). Mean follow-up times were different (6.4 years in the trauma group, 7.1 years in the degenerative group; p<0.01), although this was not thought to be clinically significant. The degenerative group was found to have a significantly higher reoperation rate for CASP (10/100 vs. 0/46, p=0.031, Fisher's Exact Test), and rate of RASP (20/100 vs. 1/32, p=0.025) Conclusion: This is the only cohort study to our knowledge comparing surgery for CASP in trauma patients to those with degenerative disease. A higher rate of repeat surgery in degenerative disease patients was found. This suggests that CASP is more related to patient factors predisposing to progressive degenerative disease and not increased mechanical stress.

Clinical adjacent-segment pathology after central corpectomy for cervical spondylotic myelopathy: incidence and risk factors.

OBJECTIVE The goal of this study was to investigate the prevalence and risk factors of clinical adjacent-segment pathology (CASP) following central corpectomy for cervical spondylotic myelopathy (CSM) or ossification of the posterior longitudinal ligament (OPLL). METHODS The authors reviewed 353 cases involving patients operated on by a single surgeon with a minimum 12-month follow-up after central corpectomy for CSM or OPLL between 1995 and 2007. Patients with symptoms consistent with CASP at follow-up were selected for the study. The authors analyzed the prevalence and risk factors for CASP after central corpectomy for CSM/OPLL. RESULTS Fourteen patients (13 male, 1 female; mean age 46.9 ± 7.7 years) were diagnosed with symptoms of CASP (3.9% of 353 patients) at follow-up. The mean interval between the initial surgery and presentation with symptoms of CASP was 95.6 ± 54.1 months (range 40-213 months). Preoperative Nurick grades ranged from 2 to 5 (mean 3.5 ± 1.2), and the Nurick grades at follow-up ranged from 1 to 5 (mean 3.0 ± 1.3, p = 0.27). Twelve patients had myelopathic symptoms and 2 had radiculopathy at follow-up. Patients with poorer preoperative Nurick grades had a higher risk for development of CASP (HR 2.6 [95% CI 1.2-5.3], p = 0.01). CONCLUSIONS In the present study, CASP was seen in 3.9% of patients following central corpectomy for CSM/OPLL. The risk of CASP after central corpectomy for CSM/OPLL was higher in patients with poorer preoperative Nurick grades.

Cervical Radiculopathy: Incidence and Treatment of 1,420 Consecutive Cases.

Study DesignRetrospective case series.PurposeTo determine the incidence of cervical radiculopathy requiring operative intervention by level and to report on the methods of treatment.Overview of LiteratureCervical radiculopathy is a common cause of pain and can result in progressive neurological deficits. Although the pathology is well understood, the actual incidence of cervical radiculopathy at particular spinal levels ultimately requiring operative intervention is unknown.MethodsA large consecutive series of patients operated on by a single surgeon were retrospectively analyzed. The incidence of cervical radiculopathy at each level was defined for every patient. Procedures used for operative treatment were noted. Health related quality of life (HRQL) scores were collected both pre-operatively and postoperatively.ResultsThere were 1305 primary and 115 revision operations performed. The most common primary procedures performed were anterior cervical discectomy and fusion (ACDF, 50%) and anterior cervical corpectomy and fusion (ACCF, 28%). The most commonly affected levels were C6 (66%) and C7 (62%). Reasons for revision were pseudarthrosis (27%), clinical adjacent segment pathology (CASP, 63%), persistent radiculopathy (11%), and hardware-related (2.6%). The most common procedures performed in the revision group were posterior cervical decompression and fusion (PCDF, 42%) and ACDF (40%). The most commonly affected levels were C7 (43%) and C5 (30%). Among patients that had their index surgery at our institution, the revision rate was 6.4%. In both primary and revision cases there was a significant improvement in Neck Disability Index and visual analogue scale scores postoperatively. Postoperative HRQL scores in the revision cases were significantly worse than those in the primary cases (p <0.01).ConclusionsThis study provides the largest description of the incidence of cervical radiculopathy by level and operative outcomes in patients undergoing cervical decompression. The incidence of CASP was 4.2% in 3.3 years in this single institution series.

Clinical Adjacent-Segment Pathology after Anterior Cervical Discectomy and Fusion: Results after a Minimum Ten-Year Follow-Up

Clinical Adjacent-Segment Pathology after Anterior Cervical Discectomy and Fusion: Results after a Minimum Ten-Year Follow-Up

Risk factors for adjacent segment pathology requiring additional surgery after single-level spinal fusion: impact of pre-existing spinal stenosis demonstrated by preoperative myelography.

We determined the incidence of and risk factors for clinical adjacent segment pathology (C-ASP) requiring additional surgeries among patients previously treated with one-segment lumbar decompression and fusion surgery. We retrospectively analysed 161 consecutive patients who underwent one-segment lumbar decompression and fusion surgery for L4 degenerative spondylolisthesis. Patient age, sex, body mass index (BMI), facet orientation and tropism, laminar inclination angle, spinal canal stenosis ratio [on myelography and magnetic resonance imaging (MRI)], preoperative adjacent segment instability, arthrodesis type, pseudarthrosis, segmental lordosis at L4-5, and the present L4 slip were evaluated by a log-rank test using the Kaplan-Meier method. A multivariate Cox proportional-hazards model was used to analyse all factors found significant by the log-rank test. Of 161 patients, 22 patients (13.7%) had additional surgeries at cranial segments located adjacent to the index surgery's location. Pre-existing canal stenosis ≥47% at the adjacent segment on myelography, greater facet tropism, and high BMI were significant risk factors for C-ASP. The estimated incidences at 10years postoperatively for each of these factors were 51.3, 39.6, and 32.5%, and the risks for C-ASP were 4.9, 3.7, and, 3.1 times higher than their counterparts, respectively. Notably, spinal canal stenosis on myelography, but not on MRI, was found to be a significant risk factor for C-ASP (log-rank test P<0.0001 and 0.299, respectively). Pre-existing spinal stenosis, greater facet tropism, and higher BMI significantly increased C-ASP risk. Myelography is a more accurate method for detecting latent spinal canal stenosis as a risk factor for C-ASP.

New Classification for Clinically Symptomatic Adjacent Segment Pathology in Cervical Disc Disease.

Study DesignClinical adjacent segment pathology (CASP) is common after cervical disc surgery. A critical examination of 320 patients operated for cervical disc prolapse revealed that CASP can also occur in patients with congenital and degenerative fusion of cervical spine. This has not been studied in depth and there is a need for a practically applicable classification of CASP.PurposeTo develop a new classification scheme of CASP.Overview of LiteratureA review of the literature did not reveal a practically applicable classification incorporating the occurrence of CASP in congenital and degenerative fusion cases.MethodsThis was a retrospective analysis of 320 patients operated (509 disc spaces) on for cervical disc prolapse. Cases (n=316) were followed-up for 3-11 years. Random sampling of 220 patients with postoperative magnetic resonance imaging (MRI) in 165 cases was analyzed.ResultsSix symptomatic CASP cases required resurgery (1.9%), eight cases involved MRI proven CASP with axial neck pain only and 13 patients were asymptomatic with radiological adjacent segment pathology (RASP). The frequency rate was 8.5% (27/316). Four cases of congenital or degenerative fusion of vertebra developed CASP requiring surgery. CASP is classified as primary or secondary follows. Primary A1 was congenital fusion of vertebra and primary A2 was degenerative fusion of the vertebra. Secondary, which was after cervical disc surgery, comprised B1 (RASP in asymptomatic patients), B2 (CASP in patients with axial neck pain), and B3 (CASP with myeloradiculopathy). B3 was subdivided into single-level CASP (B3a) and multiple-level CASP (B3b).ConclusionsSymptomatic CASP requiring resurgery is infrequent. CASP can occur in patients with congenital and degenerative fusion of the cervical spine. A new classification for CASP along with treatment strategy is proposed. Patients in Primary CASP and B3 CASP require resurgery while others require only observation.

Risk-factor analysis of adjacent-segment pathology requiring surgery following anterior, posterior, fusion, and nonfusion cervical spine operations: survivorship analysis of 1358 patients.

Adjacent-segment pathology is an important issue involving the cervical spine, but there have been few comprehensive studies of this problem. The purpose of the current study was to determine the risk factors for adjacent-segment pathology and to compare the survivorship of adjacent segments in patients who underwent cervical spine operations including arthrodesis and motion-sparing procedures. This was a retrospective analysis of a consecutive series of 1358 patients with radiculopathy, myelopathy, or myeloradiculopathy who underwent cervical spine surgery performed by a single surgeon. We calculated the annual incidence of adjacent-segment pathology requiring surgery and, with use of Kaplan-Meier analysis, determined survivorship. Cox regression analysis was used to identify risk factors. The index surgical procedures included cervical arthrodesis (1095 patients; 1038 anterior, twenty-nine posterior, and twenty-eight combined anterior and posterior), posterior decompression (214 patients; 145 laminoplasty and sixty-nine foraminotomy), arthroplasty (thirty-two patients), and a combination of arthroplasty and anterior arthrodesis (seventeen patients). Secondary surgery on adjacent segments occurred at a relatively constant rate of 2.3% per year (95% confidence interval, 1.9 to 2.9). Kaplan-Meier analysis predicted that 21.9% of patients would need secondary surgery on adjacent segments by ten years postoperatively. Factors increasing the risk were smoking, female sex, and type of procedure. The posterior arthrodesis group (posterior-only or combined anterior and posterior arthrodesis) had a 7.5-times greater risk of adjacent-segment pathology requiring reoperation than posterior decompression, and a 3.0-times greater risk than the anterior arthrodesis group. However, when we compared the anterior cervical arthrodesis group, the arthroplasty group (arthroplasty or hybrid arthroplasty), and the posterior decompression group to each other, there were no significant differences. Age, neurological diagnosis, diabetes, and number of surgically treated segments were not significant risk factors. Patients treated with posterior or combined anterior and posterior arthrodesis were far more likely to develop clinical adjacent-segment pathology requiring surgery than those treated with posterior decompression or anterior arthrodesis. Smokers and women had a higher chance of clinical adjacent-segment pathology after cervical spine surgery.

Commentary on: “Sagittal alignment as a predictor of clinical adjacent segment pathology requiring surgery after anterior cervical arthrodesis”

COMMENTARY ON Park MS, Kelly MP, Lee D-H, et al. Sagittal alignment as a predictor of clinical adjacent segment pathology requiring surgery after anterior cervical arthrodesis. Spine J 2014;14:1228–34 ( in this issue ).

Clinical adjacent-segment pathology after anterior cervical discectomy and fusion: results after a minimum of 10-year follow-up

Background contextAnterior cervical discectomy and fusion using cervical plates has been seen as effective at relieving cervical radiculopathy and myelopathy symptoms. Although it is commonly used, subsequent disc degeneration at levels adjacent to the fusion remains an important problem. However, data on the frequency, impact, and predisposing factors for this pathology are still rare. PurposeTo evaluate the incidence, predisposing factors, and impact of radiographic and clinical adjacent-segment pathologies after anterior cervical discectomy and fusion using cervical plates and to analyze the efficacy of this surgical method over the long term, after a minimum follow-up period of 10 years. Study designRetrospective clinical study. Patient sampleOur study was a retrospective analysis of 177 patients who underwent anterior cervical discectomy and fusion using cervical plates, with follow-up periods of at least 10 years (mean 16.2 years). Outcome measuresRadiographic adjacent-segment pathology using plain radiographs and clinical adjacent-segment pathology after anterior cervical discectomy and fusion using cervical plates. MethodsWe defined a new grading system of plain radiographic evidence of degenerative changes in adjacent discs after anterior cervical discectomy and fusion using cervical plates; Grade 0 is considered normal, and Grade V consists the presence of posterior osteophytes and a decrease in disc height to less than 50% of normal. The incidence, predisposing factors, and impact of radiographic and clinical adjacent-segment pathologies were analyzed according to etiologies, number of fused segments, and plate-to-disc distance. ResultsRadiographic and clinical adjacent-segment pathologies were found in 92.1% and 19.2%, respectively, of patients. By etiology, clinical adjacent-segment pathology was observed in 13.5% of patients who had sustained trauma, 12.7% of those with disc herniation, and 33.3% of those with spondylosis. By number of fused segments, clinical adjacent-segment pathology was found in 13.2% of patients who underwent single-level fusion and in 32.1% of those who underwent multilevel fusion surgeries. Patients with a plate-to-disc distance of less than 5 mm, who had spondylosis, or who underwent multilevel fusion had a higher incidence of clinical adjacent-segment pathology after anterior cervical discectomy and fusion using cervical plates than other groups did (p<.05). Of all patients, only 6.8% needed follow-up surgery. ConclusionsWe found that over the long term, at a minimum follow-up point of 10 years, a plate-to-disc distance of less than 5 mm, having spondylosis, and undergoing multilevel fusion were predisposing factors for the occurrence of clinical adjacent-segment pathology. Nevertheless, the incidence of clinical findings of adjacent-segment pathology was much lower than the incidence of radiographic findings. Also, the rate of follow-up surgery was low. Therefore, anterior cervical discectomy and fusion using cervical plates can be considered a safe and effective procedure.