Cervical Spinal Fusion: 16-Year Trends in Epidemiology, Indications, and In-Hospital Outcomes by Surgical Approach

Local FK506 delivery induces osteogenesis in rat bone defect and rabbit spine fusion models

Bone grafting procedures are commonly used for the repair, regeneration, and fusion of bones in a wide range of orthopaedic surgeries, including large bone defects and spine fusion procedures. Autografts are the clinical gold standard, though recombinant human bone morphogenetic proteins (rhBMPs) are often used, particularly in difficult clinical situations. However, treatment with rhBMPs can have off-target effects and increase surgical costs, adding to patients' already high economic and mental burden. Recent studies have identified that FDA-approved immunosuppressant drug, FK506 (Tacrolimus), can also activate the BMP pathway by binding to its inhibitors. This study tested the hypothesis that FK506, as a standalone treatment, could induce osteogenic differentiation of human mesenchymal stromal cells (hMSCs), as well as functional bone formation in a rat segmental bone defect model and rabbit spinal fusion model. FK506 enhanced osteogenic differentiation and mineralization of hMSCs in vitro. Standalone treatment with FK506 delivered on a collagen sponge produced consistent bone bridging of a critically sized rat femoral defect with functional mechanical properties comparable to naïve bone. In a rabbit single level posterolateral spine fusion model, treatment with FK506 delivered on a collagen sponge successfully fused the L5-L6 vertebrae at rates comparable to rhBMP-2 treatment. These data demonstrate the ability of FK506 to induce bone formation in human cells and two challenging in vivo models, and indicate FK506 can be utilized to treat a variety of spine disorders.

Prescription Trends of Opioid and Nonopioid Controlled Prescription Adjunctive Analgesics Before and After Cervical Spinal Surgery: A Retrospective Cohort Study

OBJECTIVE

Cervical spine surgery may be needed in those with refractory pain or neurologic deficits to improve outcomes in patients with cervical spine disease. However, consensus varies in the literature on the effect of surgery on opioid use. The objectives of this study were to analyze prescription rates of multiple controlled substances before and after cervical spine surgery and distinguish factors that may have contributed to opioid use after surgery.

DESIGN

This is a retrospective cohort study analyzing prescription trends of various controlled substances in 632 patients who underwent cervical spine surgery from 2019 to 2021.

RESULTS

Opioids have the largest rise in prescriptions at 3- and 6-mo time points after cervical spine surgery. A significant association ( P < 0.001) was found between opioid use 1 yr before and 1 yr after cervical spine surgery. Exposure to opioids before surgery (odds ratio = 2.77, 95% confidence interval = 1.43-5.51, P = 0.003) and higher morphine milligram equivalent dose (odds ratio = 1.02, 95% confidence interval =1.01-1.04, P = 0.012) were found to be associated with opioid use after surgery. Significantly more females were prescribed controlled substances ( P = 0002).

CONCLUSIONS

Higher morphine milligram equivalent dose and opioid exposure before surgery are important factors in predicting postsurgical opioid use.

Geospatial Evaluation of Disparities in Access to Cervical Spine Fusion in Metropolitan Areas Across the United States

STUDY DESIGN

Retrospective study with epidemiologic analysis of public Medicare data.

OBJECTIVE

The purpose of this study is to use geospatial analysis to identify disparities in access to cervical spine fusions in metropolitan Medicare populations.

SUMMARY OF BACKGROUND DATA

Cervical spine fusion is among the most common elective procedures performed by spine surgeons and is the most common surgical intervention for degenerative cervical spine disease. Although some studies have examined demographic and socioeconomic trends in cervical spine fusion, few have attempted to identify where disparities exist and quantify them at a community level.

METHODS

Center for Medicare and Medicaid Services physician billing and Medicare demographic data sets from 2013 to 2020 were filtered to contain only cervical spine fusion procedures and then combined with US Census socioeconomic data. The Moran Index geospatial clustering algorithm was used to identify statistically significant hotspot and coldspots of cervical spine fusions per 100,000 Medicare members at a county level. Univariate and multivariate analysis was subsequently conducted to identify demographic and socioeconomic factors that are associated with access to care.

RESULTS

A total of 285,405 cervical spine fusions were analyzed. Hotspots of cervical spine fusion were located in the South, while coldspots were throughout the Northern Midwest, the Northeast, South Florida, and West Coast. The percent of Medicare patients that were Black was the largest negative predictor of cervical spine fusions per 100,000 Medicare members ( β =-0.13, 95% CI: -0.16, -0.10).

CONCLUSIONS

Barriers to access can have significant impacts on health outcomes, and these impacts can be disproportionately felt by marginalized groups. Accounting for socioeconomic disadvantage and geography, this analysis found the Black race to be a significant negative predictor of access to cervical spine fusions. Future studies are needed to further explore potential socioeconomic barriers that exist in access to specialized surgical care.

LEVEL OF EVIDENCE

Level III-retrospective.

Stopping at C2 Versus C3/4 in Elective Posterior Cervical Decompression and Fusion: A 5-Year Follow-up Study

STUDY DESIGN

This is a retrospective cohort study.

OBJECTIVE

In patients undergoing elective posterior cervical laminectomy and fusion (PCLF) with a minimum of 5-year follow-up, we sought to compare reoperation rates between patients with an upper instrumented vertebra (UIV) of C2 versus C3/4.

SUMMARY OF BACKGROUND DATA

The long-term outcomes of choosing between C2 versus C3/4 as the UIV in PCLF remain unclear.

METHODS

A single-institution, retrospective cohort study from a prospective registry was conducted of patients undergoing elective, degenerative PCLF from December 2010 to June 2018. The primary exposure was UIV of C2 versus C3/4. The primary outcome was reoperation. Multivariable logistic regression controlled for age, smoking, diabetes, and fusion to the thoracic spine.

RESULTS

Of the 68 patients who underwent PCLF with 5-year follow-up, 27(39.7%) had a UIV of C2, and 41(60.3%) had a UIV of either C3/4. Groups had similar duration of symptoms (P=0.743), comorbidities (P>0.999), and rates of instrumentation to the thoracic spine (70.4% vs. 53.7%, P=0.210). The C2 group had significantly longer operative time (231.8±65.9 vs. 181.6±44.1 mins, P<0.001) and more fused segments (5.9±1.8 vs. 4.2±0.9, P<0.001). Reoperation rate was lower in the C2 group compared with C3/4 (7.4% vs. 19.5%), though this did not reach statistical significance (P=0.294). Multivariable logistic regression showed increased odds of reoperation for the C3/4 group compared with the C2 group (OR=3.29, 95%CI=0.59-18.11, P=0.170), though statistical significance was not reached. Similarly, the C2 group had a lower rate of instrumentation failure (7.4% vs. 12.2%, P=0.694) and adjacent segment disease/disk herniation (0% vs. 7.3%, P=0.271), though neither trend attained statistical significance.

CONCLUSIONS

Patients with a UIV of C2 had less than half the number of reoperations and less adjacent segment disease, though neither trend was statistically significant. Despite a lack of statistical significance, whether a clinically meaningful difference exists between UIV of C2 versus C3/4 should be validated in larger samples with long-term follow-up.

LEVEL OF EVIDENCE

Level-3.

The frailty-driven predictive model for failure to rescue among patients who experienced a major complication following cervical decompression and fusion: an ACS-NSQIP analysis of 3,632 cases (2011-2020)

BACKGROUND CONTEXT

Preoperative risk stratification for patients considering cervical decompression and fusion (CDF) relies on established independent risk factors to predict the probability of complications and outcomes in order to help guide pre and perioperative decision-making.

PURPOSE

This study aims to determine frailty's impact on failure to rescue (FTR), or when a mortality occurs within 30 days following a major complication.

STUDY DESIGN/SETTING

Cross-sectional retrospective analysis of retrospective and nationally-representative data.

PATIENT SAMPLE

The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was queried for all CDF cases from 2011-2020.

OUTCOME MEASURES

CDF patients who experienced a major complication were identified and FTR was calculated as death or hospice disposition within 30 days of a major complication.

METHODS

Frailty was measured by the Risk Analysis Index-Revised (RAI-Rev). Baseline patient demographics and characteristics were compared for all FTR patients. Significant factors were assessed by univariate and multivariable regression for the development of a frailty-driven predictive model for FTR. The discriminative ability of the predictive model was assessed using a receiving operating characteristic (ROC) curve analysis.

RESULTS

There were 3632 CDF patients who suffered a major complication and 7.6% (277 patients) subsequently expired or dispositioned to hospice, the definition of FTR. Independent predictors of FTR were nonelective surgery, frailty, preoperative intubation, thrombosis or embolic complication, unplanned intubation, on ventilator for >48 hours, cardiac arrest, and septic shock. Frailty, and a combination of preoperative and postoperative risk factors in a predictive model for FTR, achieved outstanding discriminatory accuracy (C-statistic = 0.901, CI: 0.883-0.919).

CONCLUSION

Preoperative and postoperative risk factors, combined with frailty, yield a highly accurate predictive model for FTR in CDF patients. Our model may guide surgical management and/or prognostication regarding the likelihood of FTR after a major complication postoperatively with CDF patients. Future studies may determine the predictive ability of this model in other neurosurgical patient populations.

Local FK506 delivery induces osteogenesis in in vivo rat bone defect and rabbit spine fusion models

Bone grafting procedures are commonly used for the repair, regeneration, and fusion of bones in in a wide range of orthopaedic surgeries, including large bone defects and spine fusion procedures. Autografts are the clinical gold standard, though recombinant human bone morphogenetic proteins (rhBMPs) are often used, particularly in difficult clinical situations. However, treatment with rhBMPs can have off-target effects and significantly increase surgical costs, adding to patients' already high economic and mental burden. Recent studies have identified that FDA-approved immunosuppressant drug, FK506 (Tacrolimus), can also activate the BMP pathway by binding to its inhibitors. This study tested the hypothesis that FK506, as a standalone treatment, could induce osteogenic differentiation of human mesenchymal stromal cells (hMSCs), as well as functional bone formation in a rat segmental bone defect model and rabbit spinal fusion model. FK506 potentiated the effect of low dose BMP-2 to enhance osteogenic differentiation and mineralization of hMSCs in vitro. Standalone treatment with FK506 delivered on a collagen sponge, produced consistent bone bridging of a rat critically-sized femoral defect with functional mechanical properties comparable to naïve bone. In a rabbit single level posterolateral spine fusion model, treatment with FK506 delivered on a collagen sponge successfully fused the L5-L6 vertebrae at rates comparable to rhBMP-2 treatment. These data demonstrate the ability of FK506 to induce bone formation in human cells and two challenging in vivo models, and indicate FK506 can be utilized either as a standalone treatment or in conjunction with rhBMP to treat a variety of spine disorders.

Cervical Vertebral Bone Quality Score Independently Predicts Distal Junctional Kyphosis After Posterior Cervical Fusion

BACKGROUND AND OBJECTIVE

Posterior cervical fusion is the surgery of choice when fusing long segments of the cervical spine. However, because of the limited presence of this pathology, there is a paucity of data in the literature about the postoperative complications of distal junctional kyphosis (DJK). We aimed to identify and report potential associations between the preoperative cervical vertebral bone quality (C-VBQ) score and the occurrence of DJK after posterior cervical fusion.

METHODS

The authors retrospectively reviewed records of patients who underwent posterior cervical fusion at a single hospital between June 1, 2010, and May 31, 2020. Patient data were screened to include patients who were >18 years old, had baseline MRI, had baseline standing cervical X-ray, had immediate postoperative standing cervical X-ray, and had clinical and radiographic follow-ups of >1 year, including a standing cervical X-ray at least 1 year postoperatively. Univariate analysis was completed between DJK and non-DJK groups, with multivariate regression completed for relevant clinical variables. Simple linear regression was completed to analyze correlation between the C-VBQ score and total degrees of kyphosis angle change.

RESULTS

Ninety-three patients were identified, of whom 19 (20.4%) had DJK and 74 (79.6%) did not. The DJK group had a significantly higher C-VBQ score than the non-DJK group (2.97 ± 0.40 vs 2.26 ± 0.46; P < .001). A significant, positive correlation was found between the C-VBQ score and the total degrees of kyphosis angle change (r 2 = 0.26; P < .001). On multivariate analysis, the C-VBQ score independently predicted DJK (odds ratio, 1.46; 95% CI, 1.27-1.67; P < .001).

CONCLUSION

We found that the C-VBQ score was an independent predictive factor of DJK after posterior cervical fusion.

Anterior cervical decompression and fusion at one and two levels: trends and factors associated with structural allograft versus synthetic cages

Background

Following decompression in anterior cervical discectomy and fusion (ACDF), reconstruction is typically done with structural allograft or a synthetic cage. Relative trends and factors associated with utilizing these implants have not been well characterized.

Methods

The PearlDiver 2011 to 2021 M157 database was used to identify adult patients undergoing 1- or 2-level ACDF. The incidence of structural allograft versus synthetic cage utilized was compared by year. Patient factors predictive of synthetic cage use as the structural interbody for ACDF were assessed with multivariable analysis. Further, the use of anterior plates was trended to provide a measure of usage of stand-alone devices (this comparison was made beginning with 2016 based on coding limitations).

Results

Of 173,833 isolated 1- or 2-level ACDF cases identified, structural allograft was used for 63,029 (36.3%) and synthetic cages were used for 110,804 (63.8%). The use of synthetic cages increased from 51.1% of cases in 2011 to 75.8% of cases in 2021 (p < 0.0001). Independent clinical predictors of synthetic cage use were: older age (odds ratio [OR] 1.02 per decade), female sex (OR 1.04), and greater ECI (OR 1.09 per 2-point increase).Independent non-clinical predictors of synthetic cage use were: geographic region (Northeast OR 1.11, South OR 1.85, and West 2.08, each relative to Midwest), and provider specialty (orthopedic OR 1.06 relative to neurosurgeons). There was an increase in the percent of synthetic cases without separately coded plate ("stand-alone" interbody cages: 21.7% in 2016 to 35.3% in 2021, p < 0.001).

Conclusions

The usage of synthetic cages in 1- and 2- level ACDF has increased relative to structural allograft between 2011 and 2021 in the United States and more recently the use of "stand-alone" synthetic cages has been on the rise. Non-clinical as well as clinical factors were associated with implant choice, suggesting room for more consistent care algorithms.

Demographic and Socioeconomic Trends in Cervical Fusion Utilization from 2004 Through 2021 and the COVID-19 Pandemic

BACKGROUND

Cervical fusion rates increased in the U.S. exponentially 1990-2014, but trends leading up to/during the COVID-19 pandemic have not been fully evaluated by patient socioeconomic status (SES). Here, we provide the most recent, comprehensive characterization of demographic and SES trends in cervical fusions, including during the pandemic.

METHODS

We collected the following variables on adults undergoing cervical fusions, 1/1/2004-3/31/2021, in Optum's Clinformatics Data Mart: age, Charlson Comorbidity Index, provider's practicing state, gender, race, education, and net worth. We performed multivariate linear and logistic regression to evaluate associations of cervical fusion rates with SES variables.

RESULTS

Cervical fusion rates increased 2004-2016, then decreased 2016-2020. Proportions of Asian, Black, and Hispanic patients undergoing cervical fusions increased (OR = 1.001,1.001,1.004, P < 0.01), with a corresponding decrease in White patients (OR = 0.996, P < 0.001) over time. There were increases in cervical fusions in higher education groups (OR = 1.006, 1.002, P < 0.001) and lowest net worth group (OR = 1.012, P < 0.001). During the pandemic, proportions of White (OR = 1.015, P < 0.01) and wealthier patients (OR ≥ 1.015, P < 0.01) undergoing cervical fusions increased.

CONCLUSIONS

We present the first documented decrease in annual cervical surgery rates in the U.S. Our data reveal a bimodal distribution for cervical fusion patients, with racial-minority, lower-net-worth, and highly-educated patients receiving increasing proportions of surgical interventions. White and wealthier patients were more likely to undergo cervical fusions during the COVID-19 pandemic, which has been reported in other areas of medicine but not yet in spine surgery. There is still considerable work needed to improve equitable access to spine care for the entire U.S.

POPULATION

Preoperative Epidural Steroid Injection Does Not Increase Infection Risk Following Posterior Cervical Surgery

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The purpose of this study was to characterize the infection risk of preoperative epidural steroid injection (ESI) in patients undergoing posterior cervical surgery.

SUMMARY OF BACKGROUND DATA

ESI is a helpful tool for alleviating pain and is often used as a diagnostic tool before cervical surgery. However, a recent small-scale study found that ESI before cervical fusion was associated with an increased risk of postoperative infection.

MATERIALS AND METHODS

Patients from 2010 to 2020 with cervical myelopathy, spondylosis, and radiculopathy who underwent posterior cervical procedure including laminectomy, laminoforaminotomy, fusion, or laminoplasty were queried from the PearlDiver database. Patients who underwent revision or fusion above C2 or who had a diagnosis of neoplasm, trauma, or preexisting infection were excluded. Patients were divided on whether they received an ESI within 30 days before the procedure and subsequently matched by age, sex, and preoperative comorbidities. The χ 2 analysis was used to calculate the risk of postoperative infection within 90 days. Logistic regression controlling for age, sex, Elixhauser Comorbidity Index, and operated levels was conducted within the unmatched population to assess infection risk for injected patients across procedure subgroups.

RESULTS

Overall, 299,417 patients were identified with 3897 having received a preoperative ESI and 295,520 who did not. Matching resulted in 975 in the injected group and 1929 in the control group. There was no significant difference in postoperative infection rate in those who received an ESI within 30 days preoperatively and those who did not (3.28% vs. 3.78%, odds ratio=0.86, 95% CI: 0.57-1.32, P =0.494). Logistic regression accounting for age, sex, Elixhauser Comorbidity Index, and levels operated demonstrated that injection did not significantly increase infection risk in any of the procedure subgroups.

CONCLUSIONS

The present study found no association between preoperative ESI within 30 days before surgery and postoperative infection in patients undergoing posterior cervical surgery.

The relative influence of model parameters on finite element analysis simulations of intervertebral body fusion device static compression performance

Non-clinical mechanical performance testing is a critical aspect of intervertebral body fusion device (IBFD) development and regulatory evaluation. Recently, stakeholders have begun leveraging computational modeling and simulations such as finite element analysis (FEA) in addition to traditional bench testing. FEA offers advantages such as reduced experiment time, lower costs associated with elimination of bench testing (e.g. specimen manufacture and test execution), and elucidating quantities of interest that traditional testing cannot provide (e.g. stress and strain distributions). However, best practices for FEA of IBFDs are not well defined, and modeler decision making can significantly influence simulation setup and results. Therefore, the goal of this study was to determine the relative influence of modeling parameters when using FEA to assess non-clinical mechanical performance of IBFDs. FEA was used to conduct a series of IBFD static uniaxial compression simulations. Several parameters relating to implant geometry, loading/boundary conditions, and material properties were carefully controlled to assess their relative influence on two output variables (IBFD stiffness and yield load). Results were most influenced by device geometry, while the effects of boundary conditions and material properties were more significant within IBFDs of identical or similar geometries. These results will aid stakeholders in the development of standardized best practices for using FEA to assess non-clinical mechanical performance of IBFDs.

Comparison of Postoperative Opioid Use After Anterior Cervical Diskectomy and Fusion or Posterior Cervical Fusion

INTRODUCTION

Posterior cervical fusion (PCF) and anterior cervical diskectomy and fusion (ACDF) are two main surgical management options for the treatment of cervical spondylotic myelopathy. Although ACDF is less invasive than PCF which should theoretically reduce postoperative pain, it is still unknown whether this leads to reduced opioid use. Our objective was to evaluate whether PCF increases postoperative opioid use compared with ACDF.

METHODS

We retrospectively identified all patients undergoing 2-level to 4-level ACDF or PCF at a single center from 2017 to 2021. Our state's prescription drug-monitoring program was queried for filled opioid prescriptions using milligrams morphine equivalents (MMEs) up to 1 year postoperatively. In-hospital opioid use was collected from the electronic medical record. Bivariate statistics compared ACDF and PCF cohorts. Multivariate linear regression was done to assess independent predictors of in-hospital opioid use and short-term (0 to 30 days), subacute (30 to 90 days), and long-term (3 to 12 months) opioid prescriptions.

RESULTS

We included 211 ACDF patients and 91 PCF patients. Patients undergoing PCF used more opioids during admission (126.7 vs. 51.0 MME, P < 0.001) and refilled more MMEs in the short-term (118.2 vs. 86.1, P = 0.001) but not subacute (33.6 vs. 19.7, P = 0.174) or long-term (85.6 vs. 47.8, P = 0.310) period. A similar percent of patients in both groups refilled at least one prescription after 90 days (39.6% vs. 33.2%, P = 0.287). PCF (β = 56.7, P = 0.001) and 30-day preoperative MMEs (β = 0.28, P = 0.041) were associated with greater in-hospital opioid requirements. PCF (β = 26.7, P = 0.039), C5 nerve root irritation (β = 51.4, P = 0.019), and a history of depression (β = 40.9, P < 0.001) were independently associated with 30-day postoperative MMEs.

CONCLUSIONS

PCF is initially more painful than ACDF but does not lead to persistent opioid use. Surgeons should optimize multimodal analgesia protocols to reduce long-term narcotic usage rather than change the surgical approach.Level of Evidence:III.

Comparison of Perioperative Complications After Anterior-Posterior Versus Posterior-Anterior-Posterior Cervical Fusion: A Retrospective Review of 153 Consecutive Cases

BACKGROUND

Although published data support the utilization of circumferential fusion to treat select cervical spine pathologies, it is unclear whether the posterior-anterior-posterior (PAP) fusion has increased risks compared with the anterior-posterior fusion.

OBJECTIVE

To evaluate the differences in perioperative complications between the 2 circumferential cervical fusion approaches.

METHODS

One hundred fifty-three consecutive adult patients who underwent single-staged circumferential cervical fusion for degenerative pathologies from 2010 to 2021 were retrospectively reviewed. Patients were stratified into the anterior-posterior ( n = 116) and PAP ( n = 37) groups. The primary outcomes assessed were major complications, reoperation, and readmission.

RESULTS

Although the PAP group was older ( P = .024), predominantly female ( P = .024), with higher baseline neck disability index ( P = .026), cervical sagittal vertical axis ( P = .001), and previous cervical operation rate ( P < .00001), the major complication, reoperation, and readmission rates were not significantly different from the 360° group. Although the PAP group had higher urinary tract infection ( P = .043) and transfusion ( P = .007) rates, higher estimated blood loss ( P = .034), and longer operative times ( P < .00001), these differences were insignificant after the multivariable analysis. Overall, operative time was associated with older age (odds ratio [OR] 17.72, P = .042), atrial fibrillation (OR 158.30, P = .045), previous cervical operation (OR 5.05, P = .051), and lower baseline C1 - 7 lordosis (OR 0.93, P = .007). Higher estimated blood loss was associated with older age (OR 1.13, P = .005), male gender (OR 323.31, P = .047), and higher baseline cervical sagittal vertical axis (OR 9.65, P = .022).

CONCLUSION

Despite some differences in preoperative and intraoperative variables, this study suggests both circumferential approaches have comparable reoperation, readmission, and complication profiles, all of which are high.

Interpretable machine learning models to predict short-term postoperative outcomes following posterior cervical fusion

By predicting short-term postoperative outcomes before surgery, patients who undergo posterior cervical fusion (PCF) surgery may benefit from more precise patient care plans that reduce the likelihood of unfavorable outcomes. We developed machine learning models for predicting short-term postoperative outcomes and incorporate these models into an open-source web application in this study. The American College of Surgeons National Surgical Quality Improvement Program database was used to identify patients who underwent PCF surgery. Prolonged length of stay, non-home discharges, and readmissions were the three outcomes that were investigated. To predict these three outcomes, machine learning models were developed and incorporated into an open access web application. A total of 6277 patients that underwent PCF surgery were included in the analysis. The most accurately predicted outcome in terms of the area under the receiver operating characteristic curve (AUROC) was the non-home discharges with a mean AUROC of 0.812, and the most accurately predicting algorithm in terms of AUROC was the LightGBM algorithm with a mean AUROC of 0.766. The following URL will take users to the open access web application created to provide predictions for individual patients based on their characteristics: https://huggingface.co/spaces/MSHS-Neurosurgery-Research/NSQIP-PCF. Machine learning techniques have a significant potential for predicting postoperative outcomes following PCF surgery. The development of predictive models as clinically useful decision-making tools may significantly improve risk assessment and prognosis as the amount of data in spinal surgery keeps growing. Here, we present predictive models for PCF surgery that are meant to accomplish the aforementioned goals and make them publicly available.

What does degeneration at the cervicothoracic junction tell us? A kinematic MRI study of 93 individuals

PURPOSE

Current decision-making in multilevel cervical fusion weighs the potential to protect adjacent levels and reduce reoperation risk by crossing the cervicothoracic junction (C7/T1) against increased operative time and risk of complication. Careful planning is required, and the planned distal and adjacent levels should be assessed for degenerative disc disease (DDD). This study assessed whether DDD at the cervicothoracic junction was associated with DDD, disc height, translational motion, or angular variation in the adjacent superior (C6/C7) or inferior (T1/T2) levels.

METHODS

This study retrospectively analyzed 93 cases with kinematic MRI. Cases were randomly selected from a database with inclusion criteria being no prior spine surgery and images having sufficient quality for analysis. DDD was assessed using Pfirrmann classification. Vertebral body bone marrow lesions were assessed using Modic changes. Disc height was measured at the mid-disc in neutral and extension. Translational motion and angular variation were calculated by assessing translational or angular motion segment integrity respectively in flexion and extension. Statistical associations were assessed with scatterplots and Kendall's tau.

RESULTS

DDD at C7/T1 was positively associated with DDD at C6/C7 (tau = 0.53, p < 0.01) and T1/T2 (tau = 0.58, p < 0.01), with greater disc height in neutral position at T1/T2 (tau = 0.22, p < 0.01), and with greater disc height in extended position at C7/T1 (tau = 0.17, p = 0.04) and at T1/T2 (tau = 0.21, p < 0.01). DDD at C7/T1 was negatively associated with angular variation at C6/C7 (tau = - 0.23, p < 0.01). No association was appreciated between DDD at C7/T1 and translational motion.

CONCLUSION

The association of DDD at the cervicothoracic junction with DDD at the adjacent levels emphasizes the necessity for careful selection of the distal level in multilevel fusion in the distal cervical spine.

Previous Emergency Department Admission Is Associated With Increased 90-Day Readmission Following Cervical Spine Surgery: Evidenced Using Propensity Score Matching

STUDY DESIGN

This was a retrospective case-control study.

OBJECTIVE

The objective of this study was to evaluate whether prior emergency department admission was associated with an increased risk for 90-day readmission following elective cervical spinal fusion.

SUMMARY OF BACKGROUND DATA

The incidence of cervical spine fusion reoperations has increased, necessitating the improvement of patient outcomes following surgery. Currently, there are no studies assessing the impact of emergency department visits before surgery on the risk of 90-day readmission following elective cervical spine surgery. This study aimed to fill this gap and identify a novel risk factor for readmission following elective cervical fusion.

METHODS

The 2016-2018 Nationwide Readmissions Database was queried for patients aged 18 years and older who underwent an elective cervical fusion. Prior emergency admissions were defined using the variable HCUP_ED in the Nationwide Readmissions Database database. Univariate analysis of patient demographic details, comorbidities, discharge disposition, and perioperative complication was evaluated using a χ 2 test followed by multivariate logistic regression.

RESULTS

In all, 2766 patients fit the inclusion criteria, and 18.62% of patients were readmitted within 90 days. Intraoperative complications, gastrointestinal complications, valvular, uncomplicated hypertension, peripheral vascular disorders, chronic obstructive pulmonary disease, cancer, and experiencing less than 3 Charlson comorbidities were identified as independent predictors of 90-day readmission. Patients with greater than 3 Charlson comorbidities (OR=0.04, 95% CI 0.01-0.12, P <0.001) and neurological complications (OR=0.29, 95% CI 0.10-0.86, P =0.026) had decreased odds for 90-day readmission. Importantly, previous emergency department visits within the calendar year before surgery were a new independent predictor of 90-day readmission (OR=9.74, 95% CI 6.86-13.83, P <0.001).

CONCLUSIONS

A positive association exists between emergency department admission history and 90-day readmission following elective cervical fusion. Screening cervical fusion patients for this history and optimizing outcomes in those patients may reduce 90-day readmission rates.

Weekend Admission Increases Risk of Readmissions Following Elective Cervical Spinal Fusion

Objective: The “weekend effect” occurs when patients cared for during weekends versus weekdays experience worse outcomes. But reasons for this effect are unclear, especially amongst patients undergoing elective cervical spinal fusion (ECSF). Our aim was to analyze whether index weekend admission affects 30- and 90-day readmission rates post-ECSF.Methods: All ECSF patients > 18 years were retrospectively identified from the 2016–2018 Healthcare Cost and Utilization Project Nationwide Readmissions Database (NRD), using unique patient linkage codes and International Classification of Diseases, Tenth Revision codes. Patient demographics, comorbidities, and outcomes were analyzed. Univariate logistic regression analyzed primary outcomes of 30- and 90-day readmission rates in weekday or weekend groups. Multivariate regression determined the impact of complications on readmission rates.Results: Compared to the weekday group (n = 125,590), the weekend group (n = 1,026) held a higher percentage of Medicare/Medicaid insurance, incurred higher costs, had longer length of stay, and fewer routine home discharge (all p < 0.001). There was no difference in comorbidity burden between weekend versus weekday admissions, as measured by the Elixhauser Comorbidity Index (p = 0.527). Weekend admissions had higher 30-day (4.30% vs. 7.60%, p < 0.001) and 90-day (7.80% vs. 16.10%, p < 0.001) readmission rates, even after adjusting for sex, age, insurance status, and comorbidities. All-cause complication rates were higher for weekend admissions (8.62% vs. 12.7%, p < 0.001), specifically deep vein thrombosis, infection, neurological conditions, and pulmonary embolism.Conclusion: Index weekend admission increases 30- and 90-day readmission rates after ECSF. In patients undergoing ECSF on weekends, postoperative care for patients at risk for specific complications will allow for improved outcomes and health care utilization.

How are Patients Describing You Online? A Natural Language Processing Driven Sentiment Analysis of Online Reviews on CSRS Surgeons

STUDY DESIGN

A quantitative analysis of written, online reviews of Cervical Spine Research Society (CSRS) surgeons.

OBJECTIVE

This study quantitatively analyzes the written reviews of members of the CSRS to report biases associated with demographic factors and frequently used words in reviews to help aid physician practices.

SUMMARY OF BACKGROUND DATA

Physician review websites have influence on a patient's selection of a provider, but written reviews are subjective. Sentiment analysis of writing through artificial intelligence can quantify surgeon reviews to provide actionable feedback.

METHODS

Online written and star-rating reviews of CSRS surgeons were obtained from healthgrades.com. A sentiment analysis package was used to obtain compound scores of each physician's reviews. The relationship between demographic variables and average sentiment score of written reviews were evaluated through t -tests. Positive and negative word and bigram frequency analysis was performed to indicate trends in the reviews' language.

RESULTS

In all, 2239 CSRS surgeon's reviews were analyzed. Analysis showed a positive correlation between the sentiment scores and overall average star-rated reviews ( r2 =0.60, P <0.01). There was no difference in review sentiment by provider sex. However, the age of surgeons showed a significant difference as those <55 had more positive reviews (mean=+0.50) than surgeons >=55 (mean=+0.37) ( P <0.01). The most positive reviews focused both on pain and behavioral factors, whereas the most negative focused mainly on pain. Behavioral attributes increased the odds of receiving positive reviews while pain decreased them.

CONCLUSION

The top-rated surgeons were described as considerate providers and effective at managing pain in their most frequently used words and bigrams. However, the worst-rated ones were mainly described as unable to relieve pain. Through quantitative analysis of physician reviews, pain is a clear factor contributing to both positive and negative reviews of surgeons, reinforcing the need for proper pain expectation management.

LEVEL OF EVIDENCE

Level 4-retrospective case-control study.

Evaluation of enlarged laminectomy with lateral mass screw fixation in relieving nerve root symptoms and correcting kyphosis for cervical myelopathy and radiculopathy

Purpose

This study aimed to compare the surgical efficacy of enlarged laminectomy with lateral mass screw fixation (EL-LMSF) and anterior cervical decompression and fusion (ACDF) for multilevel cervical myelopathy and radiculopathy (CMR) related to kyphosis.

Methods

75 patients were retrospectively reviewed and divided into ACDF and EL-LMSF group. Clinical results including operative time, blood loss, and postoperative complications were compared. The JOA scoring system was used to evaluate spinal cord function and the VAS score evaluate nerve root pain severity. Cervical alignment a C2-C7 was measured with Cobb method and compared to confirm the reconstruction effect.

Results

Data on 75 patients (M/F: 41:34; EL-LMSF/ACDF:42/33) with the mean age of 57.5 years (range 43-72 year old) were reviewed retrospectively. Discectomy and/or sub-toal corpectomy in ACDF group was performed with a mean of 3.24 levels (range, 3-4). Enlarged laminectomy in EL-LMSF group was performed with a mean of 3.89 enlarged levels (range, 3-5). The procedure of ACDF group showed a shorter operation time (103 ± 22 min vs. 125 ± 37 min, P = 0.000) and less blood loss (78 ± 15 ml vs. 226 ± 31 ml, P = 0.000) compared than that of the EL-LMSF group. Patients treated with EL-LMSF indicated lower VAS for upper extremity (1.3 ± 1.7 vs. 3.3 ± 1.3, P = 0.003) and better curvature corrected (10.7 ± 4.2° vs. 8.5 ± 3.5°, P = 0.013). The difference were of statistical significance. No statistical difference was found after surgery in the JOA score (14.1 ± 1.7 vs. 13.5 ± 2.1, P = 0.222). During the follow-up period, 15.2% of patients in the ACDF group had complications including 2 cases with transient dysphagia, 1 case with C5 palsy, 1 case with axial pain, and 1 case with screw pullout 3 month after surgery. However, only 9.5% of cases in the EL-LMSF group experienced complications, including 3 cases of axial pain and 1 case of epidural hematoma.

Conclusion

The EL-LMSF procedure requires a longer operation time and more blood loss because of the incision of the stenosed foramen. However, the procedure has obvious advantages in relieving nerve root symptoms and correcting cervical curvature with fewer postoperative complications.

Comparative Analysis of 30-Day Readmission, Reoperation, and Morbidity between Posterior Cervical Decompression and Fusion Performed in Inpatient and Outpatient Settings

STUDY DESIGN

A retrospective cohort study.

PURPOSE

To compare 30-day readmission, reoperation, and morbidity for patients undergoing posterior cervical decompression and fusion (PCDF) in inpatient vs. outpatient settings.

OVERVIEW OF LITERATURE

PCDF has recently been increasingly performed in outpatient settings, often utilizing minimally invasive techniques. However, literature evaluating short-term outcomes for PCDF is scarce. Moreover, no currently large-scale database studies have compared short-term outcomes between PCDF performed in the inpatient and outpatient settings.

METHODS

Patients who underwent PCDF from 2005 to 2018 were identified using the National Surgical Quality Improvement Program database. Regression analysis was utilized to compare primary outcomes between surgical settings and evaluate for predictors thereof.

RESULTS

We identified 8,912 patients. Unadjusted analysis revealed that outpatients had lower readmission (4.7% vs. 8.8%, p =0.020), reoperation (1.7% vs. 3.8%, p =0.038), and morbidity (4.5% vs. 11.2%, p <0.001) rates. After adjusting for baseline differences, readmission, reoperation, and morbidity no longer statistically differed between surgical settings. Outpatients had lower operative time (126 minutes vs. 179 minutes) and levels fused (1.8 vs. 2.2) (p <0.001). Multivariate analysis revealed that age (p =0.008; odds ratio [OR], 1.012), weight loss (p =0.045; OR, 2.444), and increased creatinine (p <0.001; OR, 2.233) independently predicted readmission. The American Society of Anesthesiologists (ASA) classification of ≥3 predicted reoperation (p =0.028; OR, 1.406). Rehabilitation discharge (p <0.001; OR, 1.412), ASA-class of ≥3 (p =0.008; OR, 1.296), decreased hematocrit (p <0.001; OR, 1.700), and operative time (p <0.001; OR, 1.005) predicted morbidity.

CONCLUSIONS

The 30-day outcomes were statistically similar between surgical settings, indicating that PCDF can be safely performed as an outpatient procedure. Surrogates for poor health predicted negative outcomes. These results are particularly important as we continue to shift spinal surgery to outpatient centers. This importance has been highlighted by the need to unburden inpatient sites, particularly during public health emergencies, such as the coronavirus disease 2019 pandemic.

The Impact of Osteoporosis on 2-Year Outcomes in Patients Undergoing Long Cervical Fusion

INTRODUCTION

Osteoporosis affects nearly 200 million individuals worldwide. Given this notable disease burden, there have been increased efforts to investigate complications in patients with osteoporosis undergoing cervical fusion (CF). However, there are limited data regarding long-term outcomes in osteoporotic patients in the setting of ≥4-level cervical fusion.

METHODS

The New York State Statewide Planning and Research Cooperative System database was used to identify patients who underwent posterior or combined anterior-posterior ≥4-level CF for cervical radiculopathy or myelopathy from 2009 to 2011, with a minimum follow-up surveillance of 2 years. The following were compared between patients with and without osteoporosis: demographics, hospital-related parameters, medical/surgical complications, readmissions, and revisions. Binary multivariate stepwise logistic regression was used to identify independent predictors of outcomes.

RESULTS

A total of 2,604 patients were included (osteoporosis: n = 136 (5.2%); nonosteoporosis: n = 2,468). Patients with osteoporosis were older (66.9 ± 11.2 vs. 60.0 ± 11.4 years, P < 0.001), more often female (75.7% vs. 36.2%, P < 0.001), and White (80.0% vs. 65.3%, P = 0.007). Both cohorts had comparable comorbidity burdens (Charlson/Deyo: 1.1 ± 1.2 vs. 1.0 ± 1.3, P = 0.262), total hospital charges ($100,953 ± 94,933 vs. $91,618 ± 78,327, P = 0.181), and length of stay (9.7 ± 10.4 vs. 8.4 ± 9.6 days, P = 0.109). Patients with osteoporosis incurred higher rates of overall medical complication rates (41.9% vs. 29.4%, P = 0.002) and individual surgical complications, such as nonunion (2.9% vs. 0.7%, P = 0.006). Osteoporosis was associated with medical complications (OR = 1.57, P = 0.021), surgical complications (OR = 1.52, P = 0.030), and readmissions (OR = 1.86, P = 0.003) at 2 years.

DISCUSSION

Among patients who underwent multilevel cervical fusion, those with osteoporosis had higher risk of adverse postoperative outcomes at two years. These data indicate that preoperative screening and management of osteoporosis may be important for optimizing long-term outcomes in patients who require multilevel CF.

DATA AVAILABILITY AND TRIAL REGISTRATION NUMBERS

The data used in this study are available for public use at https://www.health.ny.gov/statistics/sparcs/.

Instrumentation Across the Cervicothoracic Junction Does Not Improve Patient-reported Outcomes in Multilevel Posterior Cervical Decompression and Fusion

STUDY DESIGN

This was a retrospective cohort.

OBJECTIVE

The objective of this study was to determine if instrumentation across the cervicothoracic junction (CTJ) in elective multilevel posterior cervical decompression and fusion (PCF) is associated with improved patient-reported outcome measures (PROMs).

SUMMARY OF BACKGROUND DATA

Fusion across the CTJ may result in lower revision rates at the expense of prolonged operative duration. However, it is unclear whether constructs crossing the CTJ affect PROMs.

MATERIALS AND METHODS

Standard Query Language (SQL) identified patients with PROMs who underwent elective multilevel PCF (≥3 levels) at our institution. Patients were grouped based on anatomic construct: crossing the CTJ (crossed) versus not crossing the CTJ (noncrossed). Subgroup analysis compared constructs stopping at C7 or T1. Independent t tests and χ 2 tests were utilized for continuous and categorical data, respectively. Regression analysis controlled for baseline demographics. The α was set at 0.05.

RESULTS

Of the 160 patients included, the crossed group (92, 57.5%) had significantly more levels fused (5.27 vs. 3.71, P <0.001), longer operative duration (196 vs. 161 min, P =0.003), greater estimated blood loss (242 vs. 160 mL, P =0.021), and a decreased revision rate (1.09% vs. 10.3%, P =0.011). Neither crossing the CTJ (vs. noncrossed) nor constructs spanning C3-T1 (vs. C3-C7) were independent predictors of ∆PROMs (change in preoperative minus postoperative patient-reported outcomes) on regression analysis. However, C3-C7 constructs had a greater revision rate than C3-T1 constructs (15.6% vs. 1.96%, P =0.030).

CONCLUSION

Crossing the CTJ in patients undergoing elective multilevel PCF was not an independent predictor of improvement in PROMs at 1 year, but they experienced lower revision rates.

LEVEL OF EVIDENCE

Level III.

Depression Increases Posterior Cervical Decompression and Fusion Revision Rates and Diminishes Neck Disability Index Improvement

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

To determine if depression and/or anxiety significantly affect patient-reported outcome measures (PROMs) after posterior cervical decompression and fusion (PCDF).

SUMMARY OF BACKGROUND DATA

Mental health diagnoses are receiving increased recognition for their influence of outcomes after spine surgery. The magnitude that mental health disorders contribute to patient-reported outcomes following PCDF requires increased awareness and understanding.

MATERIALS AND METHODS

A review of electronic medical records identified patients who underwent a PCDF at a single institution during the years 2013-2020. Patients were placed into either depression/anxiety or nondepression/anxiety group based on their medical history. A delta score (∆) was calculated for all PROMs by subtracting postoperative from preoperative scores. χ 2 tests and t tests were utilized to analyze categorical and continuous data, respectively. Regression analysis determined independent predictors of change in PROMs. Alpha was set at 0.05.

RESULTS

A total of 195 patients met inclusion criteria, with 60 (30.8%) having a prior diagnosis of depression/anxiety. The depression/anxiety group was younger (58.8 vs . 63.0, P =0.012), predominantly female (53.3% vs . 31.9%, P =0.007), and more frequently required revision surgery (11.7% vs . 0.74%, P =0.001). In addition, they had worse baseline mental component (MCS-12) (42.2 vs . 48.6, P <0.001), postoperative MCS-12 (46.5 vs . 52.9, P =0.002), postoperative neck disability index (NDI) (40.7 vs . 28.5, P =0.001), ∆NDI (-1.80 vs . -8.93, P =0.010), NDI minimum clinically important difference improvement (15.0% vs . 29.6%, P =0.046), and postoperative Visual Analog Scale (VAS) Neck scores (3.63 vs . 2.48, P =0.018). Only the nondepression/anxiety group improved in MCS-12 ( P =0.002) and NDI ( P <0.001) postoperatively. Depression and/or anxiety was an independent predictor of decreased magnitude of NDI improvement on regression analysis (β=7.14, P =0.038).

CONCLUSION

Patients with history of depression or anxiety demonstrate less improvement in patient-reported outcomes and a higher revision rate after posterior cervical fusion, highlighting the importance of mental health on clinical outcomes after spine surgery.

A randomized controlled study of two different fixations in anterior cervical discectomy of multilevel cervical spondylotic myelopathy

Background: To compare the efficacy of anterior cervical discectomy and hybrid fusion (ACDHF) with short-segment plate plus self-locking, stand-alone intervertebral cages versus traditional anterior cervical discectomy and fusion (ACDF) with long-segment plate for multilevel cervical spondylotic myelopathy (MCSM). Methods: All the patients were randomly divided into two groups. 30 cases underwent ACDHF with short-segment plate and self-locking stand-alone cages (hybrid group), while the other 30 cases received ACDF with long-segment plate (control group). In patients meeting the inclusion and exclusion criteria, operation time, blood loss, postoperative drainage volume, length of stay (LOS), visual analogue scale for neck pain (VASNP) scores, Japanese Orthopaedic Association (JOA) score, and the cervical lordosis before and after the operation (5 days, 3, 6, 12 months after operation and final follow-up) were evaluated. The postoperative complications were analyzed as well. Results: All operations were performed uneventfully with followed-up. Compared with ACDF, ACDHF showed a shorter operation time, less intraoperative blood loss and postoperative drainage (p < 0.05). There were no significant difference in LOS between two groups (p ˃ 0.05). Both approaches significantly improved the JOA scores, VASNP scores and the cervical lordosis (p < 0.05). Based on Bazaz grading system, hybrid group had a lower incidence of dysphagia than control group in follow-up periods of 5 days, 3 and 6 months (p < 0.05). Conclusion: ACDF and ACDHF are both effective methods of restoring cervical lordosis following MCSM, but hybrid surgery minimizes intraoperative injury and postoperative dysphagia, making it a viable treatment option for the disorder.

Postoperative Complication Rates After One-Level Cervical Spine Surgery in Patients with Parkinson Disease: A Database Study

OBJECTIVE

Parkinson disease (PD) is a risk factor for worse surgical outcomes. The degree to which PD affects outcomes in cervical spine surgery is not well understood. Therefore, we characterize rates of postoperative complications among patients with PD who undergo cervical spine surgery.

METHODS

Using the PearlDiver database, we identified patients who underwent 1-level anterior cervical discectomy and fusion (ACDF), posterior cervical fusion (PCF), or discectomy/decompression with concomitant PD between 2011 and 2019. Patients with PD who underwent surgery and had 1 year follow-up were included. Complications 30, 60, and 90 days after surgery were identified and aggregated into body systems (e.g., respiratory and gastrointestinal). Comparison controls without concomitant PD who received cervical spine (C-spine) surgery were matched for age, sex, and comorbidities.

RESULTS

A total of 259,443 ACDFs, 30,929 PCFs, and 29,563 decompressions were identified. Of these procedures, 1117 were performed on patients with PD (0.35%). The highest 90-day complications rates in patients with PD were pulmonary and gastrointestinal related (6.05%) in those who received ACDF, neuro related (8.51%) in those who received PCF, and genitourinary related (8.76%) in those who received a decompression. Compared with patients without PD, postoperative complications rates were similar and not significantly different.

CONCLUSIONS

Patients with PD who receive ACDF have higher rates of pulmonary (6.05%), neurologic (5.24%), and psychiatric (3.23%) complications at 90 days. The differences did not reach statistical significance. This finding suggests that patients with PD do not experience higher rates of acute postoperative complications when undergoing 1-level cervical spine surgery.

The Impact of Upper Cervical Spine Alignment on Patient-reported Outcome Measures in Anterior Cervical Decompression and Fusion

STUDY DESIGN

This was a retrospective cohort study.

OBJECTIVE

To determine the extent to which the upper cervical spine compensates for malalignment in the subaxial cervical spine, and how changes in upper cervical spine sagittal alignment affect patient-reported outcomes.

SUMMARY OF BACKGROUND DATA

Previous research has investigated the relationship between clinical outcomes and radiographic parameters in the subaxial cervical spine following anterior cervical discectomy and fusion (ACDF). However, limited research exists regarding the upper cervical spine (occiput to C2), which accounts for up to 40% of neck movement and has been hypothesized to compensate for subaxial dysfunction.

MATERIALS AND METHODS

Patients undergoing ACDF for cervical radiculopathy and/or myelopathy at a single center with minimum 1-year follow-up were included. Radiographic parameters including cervical sagittal vertical axis, C0 angle, C1 inclination angle, C2 slope, Occiput-C1 angle (Oc-C1 degrees), Oc-C2 degrees, Oc-C7 degrees, C1-C2 degrees, C1-C7 degrees, and C2-C7 degrees cervical lordosis (CL) were recorded preoperatively and postoperatively. Delta (Δ) values were calculated by subtracting preoperative values from postoperative values. Correlation analysis as well as multiple linear regression analysis was used to determine relationships between radiographic and clinical outcomes. Alpha was set at 0.05.

RESULTS

A total of 264 patients were included (mean follow-up 20 mo). C2 slope significantly decreased for patients after surgery (Δ=-0.8, P =0.02), as did parameters of regional cervical lordosis (Oc-C7 degrees, C1-C7 degrees, and C2-C7 degrees; P <0.001, <0.001, and 0.01, respectively). Weak to moderate associations were observed between postoperative CL and C1 inclination ( r =-0.24, P <0.001), Oc-C1 degrees ( r =0.59, P <0.001), and C1-C2 degrees ( r =-0.23, P <0.001). Increased preoperative C1-C2 degrees and Oc-C2 degrees inversely correlated with preoperative SF-12 Mental Composite Score (MCS-12) scores ( r =-0.16, P =0.01 and r =-0.13, P =0.04). Cervical sagittal vertical axis was found to have weak but significant associations with Short Form-12 (SF-12) Physical Composite Score (PCS-12) ( r =-0.13, P =0.03) and MCS-12 ( r =0.12, P =0.05).

CONCLUSION

No clinically significant relationship between upper cervical and subaxial cervical alignment was detected for patients undergoing ACDF for neurological symptoms. Upper cervical spine alignment was not found to be a significant predictor of patient-reported outcomes after ACDF.

LEVEL OF EVIDENCE

Level III.

The Impact of Computer-Assisted Navigation on Charges and Readmission in Patients Undergoing Posterior Cervical Fusion Surgery

STUDY DESIGN

Retrospective cohort study of 2016 Healthcare Cost and Utilization Project Nationwide Readmissions Database (NRD).

OBJECTIVE

The aim was to evaluate cost and outcomes associated with navigation use on posterior cervical fusion (PCF) surgery patients.

SUMMARY OF BACKGROUND DATA

Computer-assisted navigation systems demonstrate comparable outcomes with hardware placement and procedural speed compared with traditional techniques. Innovations in technology continue to improve surgeons' performance in complicated procedures, causing need to analyze the impact on patient care.

METHODS

The 2016 NRD was queried for patients with PCF surgery ICD-10 codes. Cost and readmission rates were compared with and without navigation. Nonelective cases and patients below 18 years of age were excluded. Univariate analysis on demographics, surgical data, and total charges was performed. Lastly, multivariate analysis was performed to assess navigation's impact on cost and postoperative outcomes.

RESULTS

A total of 11,834 patients were identified, with 137 (1.2%) patients undergoing surgery with navigation and 11,697 (98.8%) patients without. Average total charge was $131,939.47 and $141,270.1 for the non-navigation and navigation cohorts, respectively ( P =0.349). Thirty-day and 90-day readmission rates were not significantly lower in patients who received navigation versus those that did not ( P =0.087). This remained insignificant after adjusting for several variables, age above 65, sex, medicare status, mental health history, and comorbidities. The model adjusting for demographic and comorbidities maintained insignificant results of navigation being associated with decreased 30-day and 90-day readmissions ( P =0.079).

CONCLUSIONS

Navigation use in PCF surgery was not associated with increased cost, and patients operated on with navigation did not significantly have increased routine discharge or decreased 90-day readmission. As a result, future studies must continue to evaluate the cost-benefit of navigation use for cervical fusion surgery.

LEVEL OF EVIDENCE

Level III.

What Is the Impact of Smoking on Patient-Reported Outcomes Following Posterior Cervical Decompression and Fusion?

OBJECTIVE

The purpose of this retrospective cohort study was to investigate the impact of smoking on patient-reported outcome measures (PROMs) following elective posterior cervical decompression and fusion (PCF).

METHODS

Electronic medical records at a single institution were reviewed for patients undergoing elective PCF. Patients were grouped based on smoking history: current smokers, former smokers, and never smokers. A delta score (Δ) was calculated for all PROMs (postoperative minus preoperative scores). Continuous and categorical data were compared using analysis of variance or χ2 tests. Regression analysis controlled for demographics. Patients were then regrouped into current smokers and nonsmokers for reanalysis.

RESULTS

A total of 195 patients were included, of whom 35 (22.1%) were current smokers, 51 (26.2%) were former smokers, and 101 (51.8%) were never smokers. Preoperative and postoperative Short-Form 12 Mental Component Score (MCS-12) were significantly lower in the current smoker group (preoperative: current 42.7, former 49.9, and never 46.6; P = 0.024; postoperative: current 44.6, former 53.7, and never 52.2; P = 0.003). Only never smokers improved in MCS-12 and Neck Disability Index following surgery. On regrouping, current smokers had significantly lower preoperative MCS-12 (42.7 vs. 47.7, P = 0.031), lower preoperative modified Japanese Orthopaedic Association (12.2 vs. 14.0, P = 0.039), greater preoperative visual analog scale Arm (6.39 vs. 4.94, P = 0.025), and lower postoperative MCS-12 (44.6 vs. 52.7, P = 0.001). Only the nonsmokers improved in MCS-12 and Neck Disability Index following surgery. On regression analysis, smoking was not an independent predictor of ΔPROMs.

CONCLUSIONS

Univariate analysis found that smokers have worse symptoms at baseline. However, smoking status was not an independent predictor of improvement in ΔPROMs following elective PCF.

Change in the Alignment and Distal Junctional Kyphosis Development after Posterior Cervical Spinal Fusion Surgery for Cervical Spondylotic Myelopathy - Risk Factor Analysis

Objective

This study analyzed the risk factors in patients who developed distal junctional kyphosis (DJK) after posterior cervical fusion.

Methods

We retrospectively analyzed the clinical and radiographic outcomes of 64 patients, aged ≥18 years (51 and 13 male and female patients, respectively), who underwent single-staged multilevel (3–6 levels) posterior cervical fusion surgery due to multiple cervical spondylotic myelopathy. The surgeries were performed by a single spinal surgeon between January 2012 and December 2017. Demographic data, clinical outcomes, and radiological results were collected. We divided the patients into a DJK group and a non-DJK group according to the presence of DJK and investigated the risk factors by comparing the differences between the two groups.

Results

Of the 64 patients, 13 developed DJK. No significant differences in clinical results were observed between the two groups before and immediately after the surgery. At the final follow-up, a higher visual analog score for neck pain was observed in the DJK group compared to the non-DJK group (p<0.01). The DJK group had a significantly lower T1 slope and a significantly higher C2-7 sagittal vertical axis (SVA) before surgery compared to the non-DJK group (p=0.03 and p<0.01, respectively). Immediately after surgery, the difference between the two groups decreased and no significant difference was observed. However, at the last followup, a significantly higher C2-7 SVA was observed in the DJK group (p<0.01). At the last follow up, there is no discrepancy in T1S-CL. In multiple logistic regression analysis, preoperative higher C2-7 SVA and preoperative lower T1 slope were identified as independent risk factors (p=0.03 and p<0.01, respectively). As a result, it was confirmed that DJK occurred along the process of returning to preoperative values.

Conclusion

DJK can be considered to be caused by cervical misalignment due to excessive change in the surgical site in patients with low T1 slope and high C2-7 SVA before surgery. This also affects the clinical outcome after surgery. It is recommended to refrain from excessive segmental lordosis changes during multilevel cervical post fusion surgery, especially in patients with a small preoperative T1 slope and a large SVA value.

Is it Better to Stop at C2 or C3/4 in Elective Posterior Cervical Decompression and Fusion?

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

(a) Compare operative variables, complications, and patient-reported outcomes (PROs) in patients with an upper instrumented vertebrae (UIV) of C2 versus C3/4, and (b) assess outcomes based on C2 screw type.

SUMMARY OF BACKGROUND DATA

When performing elective posterior cervical laminectomy and fusion (PCLF), spine surgeons must choose the upper instrumented vertebrae (UIV) at the subaxial cervical spine (C3/4) versus C2. Differences in long-term complications and PROs remain unknown.

METHODS

A single-institution, retrospective cohort study from a prospective registry was conducted. All patients undergoing elective, degenerative PCLF from December 2010 to June 2018 were included. Patients were divided into a UIV of C2 versus C3/4. Groups were 2:1 propensity matched for fusion extending to the thoracic spine. Demographics, operative, perioperative, complications, and 1-year PRO data were collected.

RESULTS

One hundred seventeen patients underwent elective PCLF and were successfully propensity matched (39 C2 vs. 78 C3/4). Groups were similar in fusion extending to the thoracic spine (P = 0.588). Expectedly, the C2 group had more levels fused (5.63 ± 1.89) compared with the C3/4 group (4.50 ± 0.91) (P = 0.001). The C2 group had significantly longer operative time (P < 0.001), yet no differences were seen in estimated blood loss (EBL) (P = 0.494) or length of stay (LOS) (P = 0.424). Both groups significantly improved all PROs at 1-year (EQ-5D; NRS-NP/AP; NDI). Both groups had the same percentage of surgical adverse events at 6.8% (P = 1.00). Between C2 screw type, no differences were seen in operative time, EBL, LOS, complications, or PROs.

CONCLUSION

In patients undergoing elective PCLF, those instrumented to C2 had only longer operative times compared with those stopping at C3/4. No differences were seen in EBL, LOS, 1-year PROs, and complications. Type of C2 screw had no impact on outcomes. Besides increased operative time, instrumenting to C2 had no detectable difference on surgical outcomes or adverse event rates.Level of Evidence: 3.

The cervical spine demonstrates less postoperative bone loss than the lumbar spine

The objective of this study is to determine the bone mineral density (BMD) changes in adjacent vertebra following anterior cervical discectomy and fusion (ACDF). Consecutive patients undergoing ACDF with available preoperative and postoperative computed tomography (CT) imaging were included. Quantitative CT measurements of screw-free cervical and first thoracic vertebra were performed. Comparisons between pre- and postoperative BMD in the vertebrae one or two levels above the upper instrumented vertebra (UIV + 1, UIV + 2) and one level below the lowest instrumented vertebra (LIV + 1) were assessed. Seventy-two patients (men, 66.7%) met the inclusion criteria. The patient population was 91.7% Caucasian with a mean age of 55.0 years. The mean interval (±SD) between surgery and secondary CT was 157 ± 23 days. Preoperative BMD (±SD) in UIV + 1 was 300.6 ± 66.2 mg/cm³ . There was a significant BMD loss of 1.5% at UIV + 1 after surgery, resulting in a postoperative BMD of 296.2 ± 64.8 mg/cm³ (p = .029). At UIV + 2 and LIV + 1, no significant differences between pre- and postoperative BMD (304.7 ± 75.7 mg/cm³ vs. 299.8 ± 74.3 mg/cm³ , 197.3 ± 50.4 mg/cm³ vs. 200.8 ± 48.7 mg/cm³ , p = .113 and p = .078, respectively) were observed. Clinical significance Our results demonstrate a small BMD decrease of 1.5% at UIV + 1. This suggests that the effect of ACDF surgery on the adjacent levels might be smaller compared to the previously described lumbar BMD loss of 10%-20% following posterior lumbar fusion procedures.

Incidence of dysphagia following posterior cervical spine surgery

Abundant literature exists describing the incidence of dysphagia following anterior cervical surgery; however, there is a paucity of literature detailing the incidence of dysphagia following posterior cervical procedures. Further characterization of this complication is important for guiding clinical prevention and management. Patients ≥ 18 years of age underwent posterior cervical fusion with laminectomy or laminoplasty between C1-T1. Pre- and post-operative dysphagia was assessed by a speech language pathologist. The patient cohort was categorized by approach: Laminectomy + Fusion (LF) and Laminoplasty (LP). Patients were excluded from radiographic analyses if they did not have both baseline and follow-up imaging. The study included 147 LF and 47 LP cases. There were no differences in baseline demographics. There were three patients with new-onset dysphagia in the LF group (1.5% incidence) and no new cases in the LP group (p = 1.000). LF patients had significantly higher rates of post-op complications (27.9% LF vs. 8.5% LP, p = 0.005) but not intra-op complications (6.1% LF vs. 2.1% LP, p = 0.456). Radiographic analysis of the entire cohort showed no significant changes in cervical lordosis, cSVA, or T1 slope. Both group comparisons showed no differences in incidence of dysphagia pre and post operatively. Based on this study, the likelihood of developing dysphagia after LF or LP are similarly low with a new onset dysphagia rate of 1.5%.

The Impact of ASA Status on Cost of Care and Length of Stay Following Posterior Cervical Decompression and Fusion

BACKGROUND

Increasing numbers of posterior cervical decompression and fusion (PCDF) over the past decade have raised the prospect of bundled payment plans. The American Society of Anesthesiologists (ASA) Physical Status Classification system may enable accurate estimation of healthcare costs, length of stay, and other postoperative outcomes in PCDF patients.

OBJECTIVE

To evaluate correlations between ASA and postoperative outcomes, length of stay (LOS), and healthcare costs in patients undergoing PCDF.

METHODS

971 patients that underwent PCDF between 2008 and 2016 at a single institution were evaluated by low (I and II) versus high (III and IV) ASA. Demographics were compared using univariate analysis. Cost of care, LOS and postoperative complications were compared using multivariable logistic and linear regression, controlling for gender, age, length of surgery and number of segments fused.

RESULTS

The high ASA cohort had greater mean age (62 vs. 55, p<0.0001) and higher Elixhauser comorbidity index (ECI) scores (p<0.0001). ASA was independently associated with longer LOS (+2.1 days, CI: 1.3-2.9; p<0.0001) and higher cost (+$2,936, CI: $1,457-$4,415; p<0.0001). High ASA patients were more likely to have a non-home discharge (3.9, 95% CI 2.8-5.6, p<0.0001), delayed extubation (3.2, 95% CI 1.4-7.3, p=0.006), ICU stay (2.4, 95% CI 1.5-3.7, p=0.0001), in-hospital complications (1.5, 95% CI 1.0-2.2, p=0.03) and 30-day (3.2, 95% CI 1.5-6.8, p=0.003) and 90-day (3.2, 95% CI 1.8-5.7, p=0.0001) readmission.

CONCLUSIONS

High ASA is strongly associated with increased costs, LOS and adverse outcomes following PCDF. Therefore, ASA could be useful for preoperative prediction of these outcomes.

Motor Bur Milling State Identification via Fast Fourier Transform Analyzing Sound Signal in Cervical Spine Posterior Decompression Surgery

Objectives

To investigate the real‐time sensitive feedback parameter of the motor bur milling state in cervical spine posterior decompression surgery, to possibly improve the safety of cervical spine posterior decompression and robot‐assisted spinal surgeries.

Methods

In this study, the cervical spine of three healthy male and three healthy female pigs were randomly selected. Six porcine cervical spine specimens were fixed to the vibration isolation system. The milling state of the motor bur was defined as the lamina cancellous bone (CA), lamina ventral corticalbone (VCO), and penetrating ventral cortical bone (PVCO). A 5‐mm bur milled the CA and VCO, and a 2‐mm bur milled the VCO and PVCO. A miniature microphone was used to collect the sound signal (SS) of milling lamina which was then extracted using Fast Fourier Transform (FFT). When using 5‐mm and 2‐mm bur to mill, the CA, VCO, and PVCO of each specimen were continuously collected at 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 kHz frequencies for SS magnitudes. The study randomly selected the SS magnitudes of the CA and VCO continuously for 2 s at 1, 2, 3, 4, and 5 kHz frequencies for statistical analyses. When milling the VCO to the PVCO, we randomly collected the SS magnitudes of the VCO for consecutive 2 s and the SS magnitudes of continuous 2 s in the penetrating state at 1, 2, 3, 4, and 5 kHz frequencies for statistical analyses. The independent sample t‐test was used to compare the SS magnitudes of different milling states extracted from the FFT to determine the motor bur milling state.

Results

The SS magnitudes of the CA and VCO of all specimens extracted from the FFT at 1, 2, and 3 kHz were statistically different (P < 0.01); three specimens were not statistically different at a specific FFT‐extracted frequency (first specimen at 5 kHz, SS magnitudes of the CA were [25.94 ± 8.74] × 10⁻³, SS magnitudes of the VCO were [28.67 ± 12.94] × 10⁻³, P = 0.440; second specimen at 4 kHz, SS magnitudes of the CA were [23.79 ± 7.94] × 10⁻³, SS magnitudes of the VCO were [24.78 ± 4.32] × 10⁻³, P = 0.629; and third specimen at 5 kHz, SS magnitudes of the CA were [16.76 ± 6.20] × 10⁻³, SS magnitudes of the VCO were [17.69 ± 6.44] × 10⁻³, P = 0.643).The SS magnitudes of the VCO and PVCO of all the specimens extracted from the FFT at each frequency were statistically different (P < 0.001).

Conclusions

Based on the FFT extraction, the SS magnitudes of the motor bur milling state between the CA and VCO, the VCO and PVCO were significantly different, confirming that the SS is a potential sensitive feedback parameter for identifying the motor bur milling state. This study could improve the safety of cervical spine posterior decompression surgery, especially of robot‐assisted surgeries.

Incidence and Risk Factors for Postoperative Venous Thromboembolic Events in Patients Undergoing Cervical Spine Surgery

STUDY DESIGN

This was a retrospective database study.

OBJECTIVE

The objective of this study was to investigate preoperative risk factors and incidence of venous thromboembolic events (VTEs) after cervical spine surgery.

SUMMARY OF BACKGROUND DATA

VTEs are preventable complications that may occur after spinal procedures. Globally, VTEs account for a major cause of morbidity and mortality. Preoperative risks factors associated with increased VTE incidence after cervical spine surgery have not been well-characterized.

MATERIALS AND METHODS

Patients undergoing anterior cervical discectomy and fusion (ACDF); posterior cervical fusion (PCF); discectomy; and decompression from 2007 to 2017 were identified using the PearlDiver Database. International Classification of Diseases (ICD) Ninth and 10th Revision codes were used to identify VTEs at 1 week, 1 month, and 3 months postoperative as well as preoperative risk factors.

RESULTS

Risk factors with the highest incidence of VTE at 3 months were primary coagulation disorder [ACDF=7.82%, odds ratio (OR)=3.96; decompression=11.24%, OR=3.03], central venous line (ACDF=5.68%, OR=2.11; PCF=12.58%, OR=2.27; decompression=10.17%, OR=2.80) and extremity paralysis (ACDF=6.59%, OR=2.73; PCF=18.80%, OR=2.99; decompression=11.86, OR=3.74). VTE incidence at 3 months for populations with these risks was significant for all surgery types (P<0.001) with the exception of patients with primary coagulation disorder who underwent PCF. Tobacco use had the lowest VTE incidence for all surgery types.

CONCLUSIONS

The total cumulative incidence of VTEs at 3-month follow-up was 3.10%, with the highest incidence of VTEs occurring within the first postoperative week (0.65% at 1 wk, 0.61% at 1 mo, 0.53% at 3 mo for ACDF; 2.56% at 1 wk, 1.93% at 1 mo, 1.45% at 3 mo for PCF; 1.37% at 1 wk, 0.93% at 1 mo, 0.91% at 3 mo for decompression). Several preoperative risk factors were found to be significant predictors for postoperative VTEs and can be used to suggest those at increased risk as well as decrease the incidence of preventable VTEs after cervical spine surgery.

LEVEL OF EVIDENCE

Level III.

Postoperative Glycemic Variability and Adverse Outcomes After Posterior Cervical Fusion

INTRODUCTION

Posterior cervical decompression and fusion (PCDF) is a procedure commonly performed to help alleviate symptoms and improve quality of life in patients experiencing cervical spondylotic myelopathy, multilevel stenosis, and cervical deformity. Although various risk factors have been linked to adverse outcomes in patients after PCDF, this is the first study that specifically explores postoperative glycemic variability and its association with adverse outcomes.

METHODS

A retrospective cohort study was conducted with a total of 264 patients after PCDF procedures that had available postoperative blood glucose measurements. Patients were divided into tertiles based on their coefficient of variation as an indicator of glycemic variability. Outcomes measured included inpatient complications, length of stay (LOS), 90-day readmission, revision, and surgical site infection rates.

RESULTS

Results showed a significant difference in glycemic variability among tertiles with respect to LOS (P = 0.01). The average LOS for the first, second, and third tertiles was 3.90 (3.20, 4.59), 5.73 (4.45, 7.00), and 6.06 (4.89, 7.22), respectively. Logistic regression analysis showed significantly higher odds of readmission (odds ratio: 4.77; P = 0.03) and surgical site infections (odds ratio: 4.35; P = 0.04) in the high glycemic variability group compared with the low glycemic variability group within 90 days of surgery. No significant difference was noted among tertiles with respect to inpatient complications.

DISCUSSION

This study establishes a relationship between postoperative glycemic variability and LOS, as well as 90-day readmission and surgical site infection rates after PCDF. Our results suggest that limiting fluctuations in blood glucose levels may curtail inpatient healthcare costs related to in-hospital stay. Although immediate postoperative glycemic variability is ultimately acceptable, before discharge, proper glucose management plans should be in place to help prevent adverse patient outcomes.

Discharge Disposition and Clinical Outcomes After Spine Surgery

OBJECTIVE

Spinal decompression with or without fusion is one of the most commonly performed procedures in spine surgery. However, there is limited evidence on the effect of discharge environment on outcomes after surgery. The purpose of this study is to identify the effects of discharge disposition setting on clinical outcomes after spine surgery.

METHODS

Patients who underwent lumbar decompression, lumbar decompression and fusion, or posterior cervical decompression and fusion surgery were retrospectively identified. All clinical and demographic data were obtained from electronic health records. Surgical outcomes included wound complications, revision surgery, "30-day" readmission (0-30 d), and "90-day" readmission (31-90 d). Discharge disposition was stratified into home/self-care, acute inpatient rehabilitation, and subacute rehabilitation. Patient-reported outcome measures including VAS Back, VAS Leg, VAS Neck, VAS Arm, PCS-12 and MCS-12, ODI, and NDI were compared between patient discharge disposition settings using the Mann-Whitney U test. Pearson's chi-square analysis was used to assess for differences in wound complications, revision surgery, 30-day readmission, or 90-day readmission rates. Multivariate logistic regression incorporating age, sex, body mass index (BMI), Charlson Comorbidity Index (CCI), and discharge disposition was used to determine independent predictors of wound complications.

RESULTS

A total of 637 patients were included in the study. A significant difference (P = 0.03) was found in wound complication based on discharge disposition, with subacute disposition having the highest proportion of wound complications (6.1%) and home disposition having the lowest (1.5%). There were no significant differences in the rates of revision surgery, 30-day readmission, or 90-day readmission between groups. Subacute rehabilitation (odds ratio: 3.67, P = 0.047) and CCI (odds ratio 1.49, P = 0.01) were independent predictors of wound complications. Significant improvement in PROMs was seen across all postacute discharge dispositions. Baseline (P = 0.02) and postoperative (P = 0.02) ODI were significantly higher among patients discharged to an acute facility (49.4 and 32.0, respectively) compared to home (42.2 and 20.0) or subacute (47.4 and 28.4) environments.

CONCLUSION

Subacute rehabilitation disposition and CCI are independent predictors of wound complications after spinal decompression surgery. Patients undergoing spine surgery have similar readmission and revision rates and experience similar clinical improvement across all postacute discharge dispositions.

Occurrence, Risk Factors, and Time Trends for Late Reoperations due to Degenerative Cervical Spine Disease: A Finnish National Register Study of 19 377 Patients Operated on Between 1999 and 2015

BACKGROUND

Surgery for degenerative cervical spine disease has escalated since the 1990s. Fusion has become the mainstay of surgery despite concerns regarding adjacent segment degeneration. The patient-specific trends in reoperations have not been studied previously.

OBJECTIVE

To analyze the occurrence, risk factors, and trends in reoperations in a long-term follow-up of all the patients operated for degenerative cervical spine disease in Finland between 1999 and 2015.

METHODS

The patients were retrospectively identified from the Hospital Discharge Registry. Reoperations were traced individually; only reoperations occurring >365 d after the primary operation were included. Time trends in reoperations and the risk factors were analyzed by regression analysis.

RESULTS

Of the 19 377 identified patients, 9.2% underwent a late reoperation at a median of 3.6 yr after the primary operation. The annual risk of reoperation was 2.4% at 2 yr, 6.6% at 5 yr, 11.1% at 10 yr, and 14.2% at 15 yr. Seventy-five percent of the late reoperations occurred within 6.5 yr of the primary operation. Foraminal stenosis, the anterior cervical decompression and fusion (ACDF) technique, male gender, weak opiate use, and young age were the most important risk factors for reoperation. There was no increase in the risk of reoperations over the follow-up period.

CONCLUSION

The risk of reoperation was stable between 1999 and 2015. The reoperation risk was highest during the first 6 postoperative years and then declined. Patients with foraminal stenosis had the highest risk of reoperation, especially when ACDF was performed.

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

BACKGROUND/CONTEXT

C2 tilt and C2 slope are quick and easy measurements to obtain on lateral radiographs and may be used to determine overall cervical sagittal alignment; however, the influence of these measurements on patient outcomes has not been well established in literature.

PURPOSE

To determine if C2 tilt and/or C2 slope predict patient outcomes better compared with conventional radiographic measures after an anterior cervical discectomy and fusion (ACDF).

STUDY DESIGN/SETTING

Retrospective cohort study.

PATIENT SAMPLE

A total of 249 patients who underwent 1 to 3 level ACDF to address radiculopathy and/or myelopathy at a single academic institution between 2011 and 2015 were identified. Patients with less than 1 year of follow-up were excluded.

OUTCOME MEASURES

Patient Reported Outcomes: Neck Disability Index (NDI), Physical Component Score-12 (PCS-12), and Mental Component Score (MCS-12), Visual Analog Score (VAS) Neck and Arm scores Cervical radiographic measurements: C2 tilt, C2 slope, C2-C7 lordosis, cervical SVA, T1 slope, T1 slope minus cervical lordosis (TS-CL), and C2-C7 ROM METHODS: Pearson correlation tests were performed to assess for significant associations between radiographic measurements and patient outcomes. Multiple linear regression models were developed adjusting for demographics and radiographic parameters to determine which factors were predictive of patient outcomes.

RESULTS

C2 tilt and TS-CL correlated with all postoperative physical outcome scores (NDI, PCS-12, VAS Neck and ARM; p<.05), however no association was seen between C2 slope and postoperative outcomes. After accounting for the presence of subaxial deformity, C2 tilt and TS-CL remained strongly correlated to patient outcome scores. With multiple linear regression, C2 tilt was a significant predictor for NDI, whereas TS-CL was a significant predictor for PCS-12, VAS Neck and VAS Arm.

CONCLUSIONS

C2 tilt significantly correlated with well-described conventional cervical parameters as well as postoperative physical outcomes measures, especially NDI, on multivariate analysis. C2 tilt may provide an easy and practical tool for predicting physical outcomes after ACDF.

Risk factor analysis of surgery-related complications in primary cervical spine surgery for degenerative diseases using a surgeon-maintained database

AIMS

This study, using a surgeon-maintained database, aimed to explore the risk factors for surgery-related complications in patients undergoing primary cervical spine surgery for degenerative diseases.

METHODS

We studied 5,015 patients with degenerative cervical diseases who underwent primary cervical spine surgery from 2012 to 2018. We investigated the effects of diseases, surgical procedures, and patient demographics on surgery-related complications. As subcategories, the presence of cervical kyphosis ≥ 10°, the presence of ossification of the posterior longitudinal ligament (OPLL) with a canal-occupying ratio ≥ 50%, and foraminotomy were selected. The surgery-related complications examined were postoperative upper limb palsy (ULP) with a manual muscle test (MMT) grade of 0 to 2 or a reduction of two grade or more in the MMT, neurological deficit except ULP, dural tear, dural leakage, surgical-site infection (SSI), and postoperative haematoma. Multivariate logistic regression analysis was performed.

RESULTS

The significant risk factors (p < 0.050) for ULP were OPLL (odds ratio (OR) 1.88, 95% confidence interval (CI) 1.29 to 2.75), foraminotomy (OR 5.38, 95% CI 3.28 to 8.82), old age (per ten years, OR 1.18, 95% CI 1.03 to 1.36), anterior spinal fusion (OR 2.85, 95% CI 1.53 to 5.34), and the number of operated levels (OR 1.25, 95% CI 1.11 to 1.40). OPLL was also a risk factor for neurological deficit except ULP (OR 5.84, 95% CI 2.80 to 12.8), dural tear (OR 1.94, 95% CI 1.11 to 3.39), and dural leakage (OR 3.15, 95% CI 1.48 to 6.68). Among OPLL patients, dural tear and dural leakage were frequently observed in those with a canal-occupying ratio ≥ 50%. Cervical rheumatoid arthritis (RA) was a risk factor for SSI (OR 10.1, 95% CI 2.66 to 38.4).

CONCLUSION

The high risk of ULP, neurological deficit except ULP, dural tear, and dural leak should be acknowledged by clinicians and OPLL patients, especially in those patients with a canal-occupying ratio ≥ 50%. Foraminotomy and RA were dominant risk factors for ULP and SSI, respectively. An awareness of these risks may help surgeons to avoid surgery-related complications in these conditions. Cite this article: Bone Joint J 2021;103-B(1):157-163.

Synthetic Cages Associated With Increased Rates of Revision Surgery and Higher Costs Compared to Allograft in ACDF in the Nonelderly Patient

Objective

The aim of this study was to compare all-cause reoperation rates and costs in nonelderly patients treated with anterior cervical discectomy and fusion (ACDF) with structural allograft versus synthetic cages for degenerative pathology.

Methods

We queried a private claims database to identify adult patients (≤ 65 years) who underwent single-level ACDF in a hospital setting using either structural allograft or a synthetic cage (polyetheretherketone, metal, or hybrid device), from 2010 to 2016. The rate of all-cause reoperations at 2 years were compared between the 2 groups. Index hospitalization costs and 90-day complication rates were also compared. Significance was set at p < 0.05.

Results

A total of 26,754 patients were included in the study. 11,514 patients (43%) underwent ACDF with structural allograft and 15,240 (57%) underwent ACDF with a synthetic cage. The patients in the allograft group were younger and more likely to be male. There was no significant difference between the 2 groups with respect to 90-day complications including: wound dehiscence, dysphagia, dysphonia, and hematoma/seroma. In the 2-year postoperative period, the synthetic cage group had a significantly higher rate of allcause reoperation compared to the allograft group (9.1% vs. 8.0%, p = 0.002). Index hospitalization costs were significantly higher in the synthetic cage group compared to those in the allograft group ($23,475 vs. $20,836, p < 0.001).

Conclusion

Structural allograft is associated with lower all-cause reoperation rates and lower index costs in nonelderly patients undergoing ACDF surgery for degenerative pathology. It is important to understand this data as we transition toward value-based care.

A comparison of experimental compressive axial loading testing with a numerical simulation of topologically optimized cervical implants made by selective laser melting

In recent years, the number of cervical interventions has increased. The stress shielding effect is a serious complication in cervical spine interventions. Topological optimization is based on finite element method structural analysis and numerical simulations. The generated design of cervical implants is made from Ti6Al4V powder by selective laser melting while the optimized cage is numerically tested for compressive axial loading and the results are compared with experimental measurement. Additive manufacturing technologies and new software possibilities in the field of structural analysis, which use the finite element method tools, help to execute implant topological optimization that is useful for clinical practice. The inner structures of the implant would be impossible to make by conventional manufacturing technologies. The resulting implant design, after modification, must fulfill strict application criteria for the area of cervical spine with respect to its material and biomechanical properties. The aim of this work was to alter the mechanical properties of the cervical intervertebral cage to address the clinical concern of the stress shielding effect by topological optimization. A methodology of cervical implant compressive axial loading numerical simulation was created, and subsequent experimental testing was done to obtain real material properties after a selective laser melting process. The weight of the optimized implant was reduced by 28.92 %. Results of the experimental testing and numerical simulation of topologically optimized design showed 10-times lower stiffness compared to the solid cage design, and the real yield strength of the optimized structure is 843.8 MPa based on experimental results.

Direct Involvement of Concomitant Foraminotomy for Radiculomyelopathy in Postoperative Upper Limb Palsy in Cervical Laminoplasty

OBJECTIVE

Although concomitant foraminotomy has been reported to increase the risk of postoperative upper limb palsy (ULP) in cervical laminoplasty, the specific effects of concomitant foraminotomy on ULP remain uncertain. This study aimed to clarify the effect of concomitant foraminotomy on ULP in cervical laminoplasty.

METHODS

We identified 19 patients who developed ULP after laminoplasty with concomitant foraminotomy for radiculomyelopathy with nerve root impingement (laminoplasty with concomitant foraminotomy group [F-group]) from 4080 patients who underwent primary cervical laminoplasty at 27 affiliated institutions between 2012 and 2018. An age- and sex-matched control group comprised patients who developed ULP after laminoplasty without concomitant foraminotomy (n = 76, 4:1 ratio with F-group). Collected data included the time of onset and distribution of ULP (side and level). The site of foraminotomy was recorded in the F-group.

RESULTS

The F-group showed a significantly higher incidence of ULP than the candidates for the control group (15.1% vs. 3.1%, P < 0.001). The site of foraminotomy was consistent with the distribution of ULP in 79% (15 of 19 patients) of the F-group. The F-group showed a significantly higher proportion of preoperative upper-limb muscle weakness (74% vs. 37%, P = 0.005) and early-onset ULP occurring by postoperative day 1 (63% vs. 33%, P = 0.02) compared with the control group.

CONCLUSIONS

Our results indicate that the foraminotomy procedure in the stenotic foramen is directly involved in ULP. Combined with a previous report suggesting that early-onset ULP is associated with thermal nerve damage, our results indicate that thermal nerve damage partly explains the increased incidence of ULP in the F-group.

Later Surgical Start Time Is Associated With Longer Length of Stay and Higher Cost in Cervical Spine Surgery

STUDY DESIGN

Retrospective study of a surgical cohort from a single, large academic institution.

OBJECTIVE

The aim of this study was to investigate associations between surgical start time, length of stay, cost, perioperative outcomes, and readmission.

SUMMARY OF BACKGROUND DATA

One retrospective study with a smaller cohort investigated associations between surgical start time and outcomes in spine surgery and found that early start times were correlated with shorter length of stay. No examinations of perioperative outcomes or cost have been performed.

METHODS

All patients undergoing anterior cervical discectomy and fusion (ACDF) and posterior cervical decompression and fusion (PCDF) were queried from a single institution from January 1, 2008 to November 30, 2016. Patients undergoing surgery that started between 12:00 AM and 6:00 AM were excluded due to their likely emergent nature. Cases starting before and after 2:00 PM were compared on the basis of length of stay and cost as the primary outcomes using multivariable logistic regression.

RESULT

The patients undergoing ACDF and PCDF were both similar on the basis of comorbidity burden, preoperative diagnosis, and number of segments fused. The patients undergoing ACDF starting after 2 PM had longer LOS values (adjusted difference of 0.65 days; 95% confidence interval [CI]: 0.28-1.03; P = 0.0006) and higher costs of hospitalization (adjusted difference of $1177; 95% CI: $549-$1806; P = 0.0002). Patients undergoing PCDF starting after 2 PM also had longer LOS values (adjusted difference of 1.19 days; 95% CI: 0.46-1.91; P = 0.001) and higher costs of hospitalization (adjusted difference of $2305; 95% CI: $826-$3785; P = 0.002).

CONCLUSION

Later surgical start time is associated with longer LOS and higher cost. These findings should be further confirmed in the spine surgical literature to investigate surgical start time as a potential cost-saving measure.

LEVEL OF EVIDENCE

3.

Regional bone mineral density differences measured by quantitative computed tomography in patients undergoing anterior cervical spine surgery

BACKGROUND CONTEXT

Clinically, the association between bone mineral density (BMD) and surgical instrumentation efficacy is well recognized. Although several studies have quantified the BMD of the human lumbar spine, comprehensive BMD data for the cervical spine is limited. The few available studies included young and healthy patient samples, which may not represent the typical cervical fusion patient. Currently no large scale study provides detailed BMD information of the cervical and first thoracic vertebrae in patients undergoing anterior cervical spine surgery.

PURPOSE

The objective of this study was to determine possible trabecular BMD variations throughout the cervical spine and first thoracic vertebra in patients undergoing anterior cervical discectomy and fusion (ACDF) and to assess the correlation between BMDs of the spinal levels C1-T1.

STUDY DESIGN/SETTING

This is a retrospective case series.

PATIENT SAMPLE

Patients undergoing ACDF from 2015 to 2018 at a single, academic institution with available preoperative CT imaging were included in this study.

OUTCOME MEASURES

The outcome measure was BMD measured by QCT.

METHODS

Patients that underwent ACDF from 2015 to 2018 at a single, academic institution were included in this study. Subjects with previous cervical instrumentation or missing/incomplete preoperative cervical spine CT imaging were excluded. Asynchronous quantitative computed tomography (QCT) measurements of the lateral masses of C1 and the C2-T1 vertebral bodies were performed. For this purpose, an elliptical region of interest that consisted exclusively of trabecular bone was selected. Any apparent sclerotic levels that might affect trabecular QCT measurements were excluded from the final analysis. Interobserver reliability of measurements was assessed by calculating the interclass correlation coefficients (ICC). Pairwise comparison of BMD was performed and correlations between the various cervical levels were evaluated. The statistical significance level was set at p<.05.

RESULTS

In all, 194 patients (men, 62.9%) met inclusion criteria. The patient population was 91.2% Caucasian with a mean age of 55.9 years and mean BMI of 28.2 kg/m². The ICC of cervical QCT measurements was excellent (ICC 0.92). The trabecular BMD was highest in the mid-cervical spine (C4) and decreased in the caudal direction (C1 average=253.3 mg/cm³, C2=276.6 mg/cm³, C3=272.2 mg/cm³, C4=283.5 mg/cm³, C5=265.1 mg/cm³, C6=235.3 mg/cm³, C7=216.8 mg/cm³, T1=184.4 mg/cm³). The BMD of C7 and T1 was significantly lower than those of all other levels. Nonetheless, significant correlations in BMD among all measured levels were observed, with a Pearson's correlation coefficient ranging from 0.507 to 0.885.

CONCLUSIONS

To the authors' knowledge this is the largest study assessing trabecular BMD of the entire cervical spine and first thoracic vertebra by QCT. The patient sample consisted of patients undergoing ACDF, which adds to the clinical relevance of the findings. Knowledge of BMD variation in the cervical spine might be useful to surgeons utilizing anterior cervical spine plate and screw systems. Due to the significant variation in cervical BMD, procedures involving instrumentation at lower density caudal levels might potentially benefit from a modification in instrumentation or surgical technique to achieve results similar to more cephalad levels.

Cervical Epidural Abscess due to Brucella Treated with Decompression and Instrumentation: A Case Report and Review of Literature

Brucella is caused by a Gram-negative bacillus and is a common disease in endemic areas where people are in close contact with animals and dairy products, but brucellar cervical epidural abscess is rare. We describe a rare case of a C5–6 brucellar epidural abscess in a veterinary doctor who was treated with decompression and instrumentation. We also review the cases of cervical brucellar epidural abscess treated with instrumentation in the literature.

Trends in Posterior Cervical Fusion for Deformity in the United States from 2000 to 2017

BACKGROUND

Posterior cervical decompression and fusion (PCF) is a common treatment for cervical spondylotic myelopathy. Treatment paradigms are shifting from simple decompression and fusion to correcting cervical deformities.

OBJECTIVE

To identify trends in PCF with an emphasis on cervical deformity and surgical complexity.

METHODS

Adults who underwent PCF from 2000 to 2017 were retrospectively identified in the Premier Healthcare Database (PHD) using International Classification of Disease Codes (ICD) 9 and 10. Patients were dichotomized into those with or without deformity diagnosis. PCF complexity was defined by adjunct surgical codes, including anterior cervical fusion, extension to thoracic levels, and osteotomy. Patient characteristics, including demographics, functional comorbidity index (FCI), and hospital characteristics, were extracted and annual procedures were projected to the US population.

RESULTS

A total of 68 415 discharges for PCF were identified. Compound annual growth rate (CAGR) of PCF from 2000 to 2017 for nondeformity cases was 9.7% and 16.5% for deformity. The demographics with the greatest growth were deformity patients aged 65 to 74 yr (15.1%). The CAGR of anterior cervical fusion and extension to thoracic levels was higher for deformity patients compared to nondeformity patients, 13.6% versus 3.9% and 20.4% versus 16.6%, respectively.

CONCLUSION

Rates of PCF for deformity are increasing at a greater rate than nondeformity PCF. The most growth was seen among deformity patients aged 65 to 74 yr. Surgical complexity is also changing with increasing use of anterior cervical fusion and extension of PCF to include thoracic levels.

Subaxial Cervical Spine Injury in the Elderly and Treatment-Related Mortality - Anterior or Posterior Approach

BACKGROUND

Subaxial cervical spine injury especially in the elderly can be associated to severe complications and disability. Until today there is no consensus concerning the best operative treatment. A potential superiority of anterior or posterior fixation is the subject of controversial discussions.

OBJECTIVES

The aim of this study was to compare the outcome of anterior and posterior fixation after subaxial cervical spine trauma in the elderly focussing on the postoperative mortality.

MATERIAL AND METHODS

A retrospective cohort analysis was performed to analyse the data of 43 patients. Especially mortality data were collected.

RESULTS

A total of 43 patients was identified. Anterior fixation was performed in 21 patients, posterior fixation was performed in 22 patients. There were no significant differences between these groups. Although statistical significance was not reached, a slightly higher mortality was found among patients undergoing anterior fixation (52,4 vs. 31,8%). Furthermore the male sex, a higher age, translation injuries, long duration of operation and hospitalisation as well as postoperative complications were slightly associated to a higher mortality.

CONCLUSIONS

Subaxial cervical spine trauma is associated to a high mortality in the elderly. Although neither anterior nor posterior fixation could show a significant superiority, every surgical decision making should be performed individually for each patient balancing the advantages and disadvantages of each method.