Risk Assessment of Anterior Lumbar Interbody Fusion Access in Degenerative Spinal Conditions

STUDY DESIGN

This was a retrospective cohort study.

OBJECTIVE

Develop an evidence-based preoperative risk assessment scoring system for patients undergoing anterior lumbar interbody fusion (ALIF).

SUMMARY OF BACKGROUND DATA

ALIF may hold advantages over other fusion techniques in sagittal restoration and fusion rates, though it introduces unique risks to vascular and abdominal structures and thus possibly increased risk of operative morbidity.

METHODS

Primary, 1 or 2-level ALIFs were identified in a surgical registry. Baseline characteristics were recorded. Axial magnetic resonance imagings at L4-L5 and L5-S1 were reviewed for vascular confluence/bifurcation or anomalous structures, and measured for operative window size/slope. To assess favorable outcomes, a clinical grade was calculated: (clinical grade=blood loss×operative duration), higher value indicating poorer outcome. To establish a risk scoring system, a base risk score algorithm was established and stratified into 5 categories: high, high to intermediate, intermediate, intermediate to low, and low. Modifiers to base risk score included age, body mass index, operative level, history of bone morphogenic protein use, calcified vasculature, spondylolisthesis grade, working window size and slope, and abnormal vasculature. Modifiers were weighted for contribution to surgical risk. A total risk score was calculated and evaluated for strength of association with clinical outcome grades by Pearson correlation coefficient.

RESULTS

A total of 65 patients were included. Mean clinical outcome grade was 5.6, mean total risk score 21.3±21.5. Multilevel procedures (L4-S1) mean total risk score was 57.3±7.8. L4-L5 mean total risk score was 23.6±5.2; L5-S1 mean total risk score 8.3±6.6. Correlation analysis demonstrated a significant and strong relationship (| r |=0.753; P <0.001) between total risk scores and clinical outcome grades.

CONCLUSION

Calculated ALIF risk scores significantly correlated with operative duration and blood loss. This scoring system represents a potential framework to facilitate clinical decision-making and risk assessment for potential ALIF candidates with degenerative spinal pathologies.

Predicting Acute Changes in Depressive Symptoms Following Lumbar Decompression

BACKGROUND

While depressive symptoms improve for most patients following minimally invasive lumbar decompression (MIS LD), for some, symptoms may worsen. This study aimed to investigate predictors of change in depressive symptoms in the short-term postoperative period following MIS LD.

METHODS

We retrospectively analyzed a prospective surgical database for patients undergoing primary MIS LD procedures from 2016 to 2020. Preoperative pain (visual analog scale back and leg) scores were recorded, and the 9-Item Patient Health Questionnaire (PHQ-9) was administered at the preoperative and postoperative (6 weeks, 12 weeks, 6 months, and 1 year) timepoints. Patients were grouped into 1 of 3 categories of depression severity based on preoperative PHQ-9 scores: minimal (0-4), mild (5-9), and moderate to severe (10-27). Postoperative change in depressive symptoms was calculated by determining differences from baseline scores to scores at 6 weeks, 12 weeks, and 6 months. Analysis of demographics, perioperative characteristics, and spinal pathologies was conducted using χ ² test. Significant factors contributing to postoperative changes in depression were analyzed using multiple linear regression analysis. Significance was set at P = 0.05.

RESULTS

The 216 patients included had a mean age of 48 years, and a majority were men (70.4%). Most patients had a preoperative diagnosis of spinal stenosis (90.3%) or herniated nucleus pulposus (69.9%). Univariate analysis identified age, ethnicity, insurance, and diabetes as significant variables among depression severity groups. Patients demonstrated significant improvements in depressive symptoms at all postoperative timepoints (P < 0.001). Multivariate analysis identified several significant predictors of postoperative change in PHQ-9, which included moderate to severe preoperative depression for all postoperative timepoints (all P ≤ 0.038), mild preoperative depression for 6 weeks and 12 weeks (both P ≤ 0.029), and private insurance (P = 0.002) and smoking status (P = 0.047) at 12 weeks.

CONCLUSION

Depression improved at all postoperative timepoints following LD. Insurance type, smoking status, and preoperative depression severity were all identified as significant predictors of postoperative changes in depressive symptoms.

CLINICAL RELEVANCE

This study explores predictors of changes in depressive symptoms following LD.

LEVEL OF EVIDENCE: 3

Impact of Lower Extremity Arthroplasty on Improvement of Quality-of-Life Outcomes Following Lumbar Fusion

BACKGROUND

Both hip-spine and knee-spine syndromes can significantly impact a patient's quality of life; however, few studies have investigated their effect on postoperative outcomes following lumbar fusion.

OBJECTIVE

Our study aimed to evaluate the impact of a prior lower extremity arthroplasty on the improvement of patient-reported outcome measures (PROMs) following lumbar fusion surgery.

METHODS

Patients undergoing primary, single, or multilevel lumbar interbody fusion were retrospectively reviewed. Patients missing preoperative PROMs were excluded. PROMs were collected preoperatively and postoperatively and included the Oswestry Disability Index (ODI), 12-Item Short Form Physical Component Summary, Patient-Reported Outcomes Measurement Information System Physical Function, and visual analog scale (VAS). A minimum clinically important difference (MCID) was calculated. Patients were categorized based on a history of hip/knee arthroplasty and propensity score matched. Intragroup improvement of PROM scores and intergroup differences in mean scores were evaluated using a paired t test and linear regression. MCID achievement differences were evaluated using logistic regression.

RESULTS

A total of 335 patients were included, with 25 having a history of hip/knee arthroplasty. Arthroplasty patients were significantly older (P = 0.001) and typically had a higher Charlson Comorbidity Index (P ≤ 0.003, both). Patients differed in spinal pathology of degenerative spondylolisthesis (P = 0.049). Nonarthroplasty patients demonstrated significant improvements in all PROMs by 2 years (P < 0.001, all). The arthroplasty group demonstrated significant improvements in all PROMs by 1 year (P < 0.031, all). Preoperative VAS back was significantly worse for nonarthroplasty patients (P = 0.035). MCID achievement did not significantly differ between groups except at 6 months for ODI (P = 0.035).

CONCLUSION

Following lumbar fusion, patients with a past surgical history did not demonstrate differences in outcome measures or MCID from those without. These results suggest that comorbid orthopedic conditions requiring surgery do not negatively impact the ability of patients to improve following lumbar fusion.

CLINICAL RELEVANCE

Prior surgical history of lower extremity arthroplasty should not discourage the use of lumbar fusion when properly indicated, as patients reported clinical improvement regardless of history of hip or knee arthroplasty.

LEVEL OF EVIDENCE: 3

Dysphagia May Attenuate Improvements in Postoperative Outcomes Following Anterior Cervical Discectomy and Fusion

BACKGROUND

Past studies outline potential risk factors for dysphagia following anterior cervical discectomy and fusion (ACDF). Few studies explored the impact of dysphagia, as measured by the swallowing quality of life (SWAL-QOL), on postoperative patient-reported outcome measure (PROM) improvement. This study aimed to determine the relationship between dysphagia and improvement in pain, disability, physical function, and mental health following ACDF.

METHODS

A retrospective review of patients undergoing primary 1- or 2-level ACDF was performed. Individuals without a completed preoperative SWAL-QOL were excluded. Outcomes were collected for visual analog scale (VAS) neck and arm pain, Neck Disability Index (NDI), Patient-Reported Outcome Measurement Information System Physical Function (PROMIS-PF), 12-Item Short Form Physical Component Score (SF-12 PCS), 9-Item Patient Health Questionnaire (PHQ-9), and SWAL-QOL. Postoperative improvement from preoperative values was evaluated using a paired t test. The impact of SWAL-QOL on each PROM was assessed using linear regression.

RESULTS

A total of 91 patients were included. Mean preoperative SWAL-QoL was 90.4, which worsened at 6 weeks and resolved by 6 months (P ≤ 0.007, both). VAS neck and arm scores significantly improved postoperatively (P < 0.001), as did the NDI score (P < 0.001). Physical function significantly improved at 12 weeks and 6 months (P ≤ 0.021, both). Depressive symptoms improved at 6 weeks and 12 weeks (P ≤ 0.007, both). Preoperatively, SWAL-QOL demonstrated significant relationships with all PROMs (P ≤ 0.005, all). At 6 weeks, 12 weeks, and 6 months (P ≤ 0.048, all), SWAL-QoL again demonstrated a similar significant association with all PROMs. Multiple regression did not demonstrate common demographic or operative variables that were significant predictors of PROMs.

CONCLUSION

Following ACDF, patients experienced a worsening of dysphagia but resolved by 12 weeks. All PROMs demonstrated significant improvements by the 6-month timepoint, except for PHQ-9. SWAL-QoL demonstrated a significant effect on all postoperative outcomes, which may suggest that this questionnaire could effectively evaluate dysphagia and predict positive or negative outcomes following ACDF.

LEVEL OF EVIDENCE

3 CLINICAL RELEVANCE: The severity of dysphagia has a significant association with pain, disability, mental health, and physical function patient-reported outcome measures in patients undergoing ACDF.

Anterior Cervical Discectomy and Fusion Results in Clinically Significant Improvements in Patients With Preoperative Sleep Difficulties

BACKGROUND

Individual items within the Patient Health Questionnaire-9 (PHQ-9) have not been assessed as predictors of postoperative outcomes. Our objective is to study the relationship between responses to individual PHQ-9 items and achievement of a minimum clinically important difference (MCID) following anterior cervical discectomy and fusion (ACDF).

METHODS

A prospective surgical database was reviewed for primary, single-level ACDF procedures performed for degenerative spinal pathology. Patient demographics, preoperative spinal pathology, and perioperative characteristics were recorded. Patient-reported outcome measures (PROMs) including PHQ-9, visual analog scale (VAS) neck and arm, Neck Disability Index, 12-item Short Form physical component score (SF-12 PCS), and Patient-Reported Outcomes Measurement Information System Physical Function were administered at preoperative and 6-week, 12-week, 6-month, 1-year, and 2-year postoperative timepoints. MCID achievement was determined by comparing postoperative PROM improvement from baseline to previously established values. Logistic regression assessed responses to each individual question of the preoperative PHQ-9 as predictors of MCID achievement in each other PROMs.

RESULTS

Sixty-six ACDF patients were included with a mean age of 47.2 years. Herniated nucleus pulposus was the most common preoperative spinal diagnosis (95.6%). The mean operative duration was 50.3 minutes, the mean estimated blood loss was 27.5 mL, and most patients were discharged on postoperative day 0 (81.8%). A majority of patients achieved MCID for all measures except SF-12 PCS. PHQ-9 question 3 significantly predicted MCID achievement for VAS neck (P = 0.045), VAS arm (P = 0.049), and SF-12 PCS (P = 0.037). No other PHQ-9 items or overall PHQ-9 scores significantly predicted MCID achievement.

CONCLUSION

Question 3 of the PHQ-9 regarding "trouble falling asleep, staying asleep, or sleeping too much" significantly predicted clinically meaningful improvement in neck pain, arm pain, and physical function following ACDF, although overall PHQ-9 scores did not. Providers should inform patients experiencing significant sleep-related difficulties that they may be especially likely to benefit from ACDF surgery.

CLINICAL RELEVANCE

Evaluation of sleep from the PHQ-9 predicts clinically relevant improvement in neck pain, arm pain, and physical function in patients undergoing ACDF.

LEVEL OF EVIDENCE: 3

How Does Open Access Publication Impact Readership and Citation Rates of Lumbar Spine Literature?

STUDY DESIGN

This was a retrospective review.

OBJECTIVE

The objective of this study was to assess the impact of open access (OA) publication on citation rates and attention scores of literature related to lumbar spine surgery.

SUMMARY OF BACKGROUND DATA

OA literature allows readers to view full-text manuscripts of research publications free of charge, however, OA publication is often associated with substantial fees for authors.

METHODS

The Altmetric database was searched for articles related to lumbar spine surgery. Title, journal, publication date, Dimensions Citations, Mendeley Readers, Altmetric Attention Score (AAS), number of public mentions, and OA status were collected for each included article. The influence of OA status on Dimensions Citations, Mendeley Readers, and each individual component of the AAS was assessed. To control for journal influence, impact of OA on Dimensions Citations and AAS was separately assessed for each of the top 10 journals contributing the most mentioned articles. The top 25 most cited articles and top 25 articles by AAS were also characterized.

RESULTS

A total of 5245 articles were included, of which 2063 were published with OA and 3182 were not. OA status was a significant, independent predictor of AAS and Mendeley Readers (both P <0.001), but not Dimensions Citations ( P =0.422). OA status significantly predicted mentions in news stories ( P =0.003), Twitter posts ( P <0.001), Facebook posts ( P <0.001), and Wikipedia citations ( P =0.011). Of the top 10 contributing journals, OA status significantly predicted Dimensions Citations for European Spine Journal , Journal of Neurosurgery: Spine , and Neurosurgery ( P ≤0.005) and predicted AAS for Spine , European Spine Journal , The Spine Journal , Journal of Neurosurgery: Spine , and Neurosurgery ( P ≤0.017, all).

DISCUSSION

OA status appeared to significantly impact public attention scores, but not citation rates, although these effects did vary based on the journal in which articles were published. Authors may want to consider OA publication based on their target audience and the goal of their research.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Impact of Body Mass Index on Postsurgical Outcomes for Workers' Compensation Patients Undergoing Minimally Invasive Transforaminal Lumbar Interbody Fusion

BACKGROUND

Increased morbidity associated with obesity imposes a greater financial burden on companies that provide insurance to their employees. Few studies have investigated the relationship between body mass index (BMI) and patient-reported outcome measures (PROMs) for minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) in the workers' compensation (WC) population.

METHODS

WC patients who underwent a primary, single-level MIS TLIF were included/grouped according to BMI: nonobese (<30 kg/m2); obese I (≥30, <35 kg/m2); severe + morbid (≥35). PROMs were collected pre- and postoperatively: visual analog scale (VAS), Oswestry Disability Index (ODI), 12-Item Short Form (SF-12) physical composite score (PCS), and Patient-Reported Outcome Measurement Information System physical function (PROMIS-PF). BMI predictive power grouping on PROMs was evaluated using simple linear regression. Established minimum clinically important difference values were used to compute achievement rates across PROMs using logistic regression.

RESULTS

A total of 116 nonobese, 70 obese I, and 61 severe + morbid patients were included. Demographics among BMI grouping significantly differed in gender, hypertensive status, and American Society of Anesthesiologists score (P ≤ 0.037, all). Operative time was significantly different in perioperative values among BMI grouping (P ≤ 0.001). Increased BMI was significantly associated with greater VAS back at 12 weeks and 2 years (P ≤ 0.026, all), greater ODI preoperatively at 12 weeks and 6 months (P ≤ 0.015, all), and decreased PROMIS-PF at 12 weeks (P ≤ 0.011, all). Mean PROMs between obese I and severe + morbid cohorts differed in SF-12 PCS at 12 weeks, only (P = 0.050). ODI overall was the only parameter for which minimum clinically important difference was achieved among BMI cohorts (P ≤ 0.023).

CONCLUSION

WC patients with increased BMI were more likely to develop significant back pain and disability at numerous postoperative timepoints compared with nonobese individuals. Our findings highlight the weight management importance within WC population to minimize back pain and disability following MIS TLIF, but provide a sense of reassurance with comparable clinical improvement regardless of BMI.

CLINICAL RELEVANCE

When considering the effect of weight, surgeons may incorporate these findings in managing patient expectations in the WC population undergoing lumbar spine surgery.

LEVEL OF EVIDENCE: 3

Validation of Veterans RAND 12-Item Physical Function Survey in Minimally Invasive Transforaminal Lumbar Interbody Fusion

BACKGROUND

Veterans RAND 12-item (VR-12) physical component score (PCS) has been validated in both veteran and US citizen populations; however, its use for spine surgery populations has not been evaluated. This study aims to correlate the VR-12 PCS survey with legacy patient-reported outcome measures (PROMs) in patients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS TLIF).

METHODS

A prospective surgical database was retrospectively assessed for MIS TLIFs performed at 1 level from March 2015 to June 2019. Inclusion criteria were elective procedures for degenerative spinal pathology. Patients were excluded if they had surgery for metastatic, traumatic, or infectious etiologies or had incomplete preoperative 12-item Short Form (SF-12) PCS or Patient-Reported Outcomes Measurement Information System physical function (PROMIS-PF) survey. Additionally, patients with any incomplete VR-12 PCS surveys through 1 year were excluded. Demographics and perioperative characteristics were recorded. Mean postoperative PROM scores and score difference from preoperative baseline were calculated at each postoperative timepoint through 1 year. The relationship of VR-12-PCS with SF-12-PCS and PROMIS PF was evaluated with a Pearson's correlation coefficient and time-independent partial correlation.

RESULTS

A total of 59 patients underwent single-level MIS TLIFs. The cohort was 44.1% women with an average age of 53.8 years, and 52.5% were obese (body mass index ≥30 kg/m2). The VR-12 PCS, SF-12 PCS, and PROMIS PF surveys had significant improvements from baseline to the 6 month through 1 year postoperative timepoints (P ≤ 0.001, all). All timepoints revealed strong VR-12-PCS correlations with SF-12-PCS and PROMIS PF (all P ≤ 0.001).

CONCLUSION

VR-12 PCS, SF-12 PCS, and PROMIS PF scores all indicate statistically significant improvements in physical function for patients following MIS TLIF. VR-12 PCS was strongly correlated with the historically validated SF-12 PCS system as well as with the more recent PROMIS PF survey. Our observations give weight to utilizing the VR-12 PCS survey as a valid measure of physical function among patients undergoing MIS TLIF.

CLINICAL RELEVANCE

This study validates VR-12 PCS to measure physical function for TLIF patients.

LEVEL OF EVIDENCE: 4

Meeting Patient Expectations and Achieving a Minimal Clinically Important Difference for Back Disability, Back Pain, and Leg Pain May Provide Predictive Utility for Achieving Patient Satisfaction Among Lumbar Decompression Patients

OBJECTIVE

Our study evaluates minimum clinically important difference (MCID) achievement for back pain/leg pain/disability and meeting preoperative expectations as predictors of patient satisfaction after minimally invasive lumbar decompression (MIS-LD) surgery.

METHODS

Single/multilevel MIS-LD procedures were identified. Patient-reported outcome measures (preoperative/postoperative), expectations (preoperative), and satisfaction (postoperative) were collected for visual analog scale (VAS) back/VAS leg/Oswestry Disability Index (ODI). Student's t-test assessed patient-reported outcome measure improvement from preoperative baseline. Correlations between outcome and satisfaction scores were evaluated using the Pearson correlation coefficient and categorized according to strength of relationship. MCID achievement and meeting expectations were evaluated as predictors of postoperative patient satisfaction with simple linear regression. Comparison of meeting expectations or achieving MCID as predictors of satisfaction scores was performed using a post hoc Suest test comparison of standardized β-coefficients.

RESULTS

A total of 329 patients were included. All outcomes improved from baselines (P < 0.001, all) at all postoperative time points and demonstrated strong and negative correlations with satisfaction scores (P < 0.001, all). Majority of patients had their expectations met for ODI/VAS back/VAS leg and achieved MCID for ODI/VAS back/VAS leg at all time points and overall. Both MCID achievement and meeting preoperative expectations demonstrated significant associations with satisfaction scores at all time points for ODI/VAS back/VAS leg. Post hoc analysis of predictors of patient satisfaction in pain and disability demonstrated that MCID achievement was an equivalent predictor to meeting patient preoperative expectations at all postoperative time points.

CONCLUSION

Pain/disability improved after MIS-LD; improvement was strongly correlated with postoperative satisfaction. Meeting expectations/MCID achievement is associated with satisfaction. MCID achievement was equivalent to meeting expectations in predicting satisfaction at all postoperative time points for pain/disability.

Presenting Mental Health Influences Postoperative Clinical Trajectory and Long-Term Patient Satisfaction After Lumbar Decompression

OBJECTIVE

To compare patient-reported outcomes (PROMs), postoperative patient-reported satisfaction, and minimum clinically important difference (MCID) achievement after minimally invasive surgery lumbar decompression (MIS-LD) in patients stratified by their preoperative 12-Item Short-Form Mental Component Score (SF-12 MCS).

METHODS

Patients who underwent single-level/multilevel MIS-LD were included. PROMs were administered preoperatively and 6 weeks/12 weeks/6 months/1 year postoperatively. Patients were grouped by preoperative SF-12 MCS. Demographic/perioperative characteristics were compared among groups using a χ² and Student t test for categorical and continuous variables, respectively. Mean PROM and postoperative satisfaction scores were compared using an unpaired Student t test. PROM improvement within cohorts was assessed with paired-samples t test. MCID achievement rates were compared using χ² analysis.

RESULTS

A total of 297 patients were included: 111 patients in SF-12 MCS <48.9 and 186 patients in the SF-12 MCS ≥48.9 cohort. Cohorts showed mean postoperative differences for visual analog scale (VAS) back score at 12 weeks, VAS leg score at 6 weeks/12 weeks, Oswestry Disability Index (ODI) at 6 weeks/12 weeks, SF-12 MCS at all postoperative time points, and 12-Item Short-Form Physical Component Score at 6 weeks/12 weeks (P < 0.022, all). Of patients in the SF-12 MCS <48.9 cohort, more achieved MCID for SF-12 MCS at all postoperative time points and ODI at 1 year (P < 0.023, all). More patients in the SF-12 MCS ≥48.9 cohort achieved MCID for VAS leg score at 12 weeks and 12-Item Short-Form Physical Component Score at 6 weeks (P < 0.038). Patients in the SF-12 MCS <48.9 cohort showed inferior postoperative satisfaction for VAS leg score at 6 weeks/12 weeks/1 year, VAS back score at 12 weeks, and ODI at all postoperative time points.

CONCLUSIONS

Patients with inferior mental health preoperatively showed worse mean short-term postoperative clinical outcome for leg/back pain, physical function and disability, short-term and long-term postoperative satisfaction for leg pain and disability, and long-term satisfaction for sleeping/lifting/walking/standing/sex/travel.

Patient Satisfaction Following Lumbar Decompression: What is the Role of Mental Health?

OBJECTIVE

To determine the association between patient-reported depressive symptoms and patient satisfaction following minimally invasive lumbar decompression (MIS LD) METHODS: Primary, single/multilevel MIS LD were identified. Patient-reported outcome measures (PROMs) collected pre-/post-operatively included VAS back/leg, ODI, PHQ-9, and SF-12 MCS. Patients rated current satisfaction level (0-10) with back/leg pain and disability. Paired Student's t-test compared each postoperative PROM score to its preoperative baseline. At each timepoint, patients were categorized by PHQ-9 and SF-12 MCS scores. One-way ANOVA compared patient satisfaction with back/leg pain and disability among PHQ-9 subgroups. Student's t-test for independent samples compared patient satisfaction between SF-12 MCS subgroups. ANCOVA assessed differences in satisfaction between depression subgroups while controlling for pre-/post-operative values in corresponding PROMs.

RESULTS

193 patients were included. All PROMs demonstrated significant postoperative improvement from 6-weeks through 2-years(p<0.001,all) except PHQ-9 2-years(p=0.874). Mean satisfaction scores ranged from 6.9-7.9(back pain), 7.3-8.0(leg pain), and 7.6-8.0(disability). Satisfaction with back/leg pain and disability significantly differed among PHQ-9 subgroups at all postoperative timepoints(p<0.001,all). Accounting for baseline and current pain/disability values, ANCOVA revealed differences between PHQ-9 subgroups only in satisfaction with back pain 2-years(p<0.001), leg pain 12-weeks/1-year/2-years(p≤0.047,all), and disability 6-months/2-years(p≤0.049,both). Satisfaction differed between SF-12 MCS subgroups at all timepoints(p≤0.047), except back pain 6-months(p=0.263). Accounting for baseline and postoperative pain/disability, ANCOVA revealed differences in satisfaction between SF-12 MCS groups only for back/leg pain 2-years(p≤0.001,both).

CONCLUSION

Independent effect of depression at long-term follow-up was significant. This highlights the importance of understanding the interaction between physical and mental health outcomes to optimize patients' perceptions of surgical outcome.

Lateral Lumbar Interbody Fusion: Single Surgeon Learning Curve

OBJECTIVE

To characterize lateral lumbar interbody fusion surgical learning curve and investigate changes in perioperative and postoperative clinical parameters associated with increased operative experience.

METHODS

In a case series, surgical learning curve was defined using 3-parameter asymptotic regression and piecewise linear regression, yielding learning phase (patients 1-53) and proficient phase (patients 54-179) cohorts. Using a 5-point grading scale, ipsilateral iliopsoas (hip-flexion) and quadriceps (knee-extension) muscle strength and thigh and groin sensory disturbances were compared for differences preoperatively versus postoperatively using χ² test. Patient-reported outcome measures were collected preoperatively and postoperatively and compared between cohorts with unpaired t test.

RESULTS

The proficient phase cohort demonstrated significantly reduced operative time, estimated blood loss, postoperative length of stay, and narcotic consumption on postoperative days 0 and 1. The proficient phase cohort displayed decreased disability at 6 weeks and 6 months and demonstrated significant improvement at all time points for disability, pain, and physical function except for 6 weeks and 2 years for physical function, whereas the learning phase cohort demonstrated improvement in disability beginning at 6 months, leg pain at all time points, and back pain through 6 months. Ipsilateral groin and thigh sensory disturbances and iliopsoas and quadriceps weakness improved with increasing operative experience.

CONCLUSIONS

The proficient phase cohort demonstrated significantly improved perioperative profile, reduced complication rate, and reduced rates of iliopsoas and quadriceps weakness. While the proficient phase cohort demonstrated earlier improvement in disability and physical function scores compared with the learning phase cohort, 2-year outcome measures did not differ. Long-term clinical outcomes suggest that patient safety and quality of life are not compromised during the learning phase, but patients may be particularly susceptible to femoral nerve injury early in a surgeon's practice.

Stand-Alone Cage Versus Anterior Plating for 1-Level and 2-Level Anterior Cervical Discectomy and Fusion: A Randomized Controlled Trial

STUDY DESIGN

Prospective, randomized controlled trial.

OBJECTIVE

The aim was to compare perioperative and radiographic outcomes between stand-alone and anterior plated 1 and 2-level anterior cervical discectomy and fusion (ACDF).

SUMMARY OF BACKGROUND DATA

ACDF with interbody spacer and separate plate/screw construct (PLATE) may be associated with a higher incidence of postoperative dysphagia, increased operative time, and other complications. Therefore, some have opted to utilize an interbody cage with integrated screws and no plate (CAGE) with good results.

MATERIALS AND METHODS

Patients with 1-level to 2-level degenerative disease were prospectively enrolled and randomized into 1 of 2 treatment arms consisting of either PLATE or CAGE reconstruction. Patients were followed for a minimum of 1 year postoperatively. Primary endpoints included improvement on patient-reported outcome metrics, construct integrity, cervical alignment, successful arthrodesis, and subsequent revision surgeries.

RESULTS

Forty-six patients were included: 12 with 1-level PLATE, 12 with 1-level CAGE, 12 with 2-level PLATE, and 10 with 2-level CAGE. For 1-level ACDF, PLATE patients reported worse swallow function on Swallowing Quality of Life Questionnaire at 6 weeks (P=0.050) and 6 months (P=0.042). Pseudarthrosis requiring revision was observed in one PLATE patient. For 2-level ACDF CAGE patients reported worse disability on neck disability index (P=0.037) at 6 weeks, as well as worse neck disability index (P=0.017) and visual analog scale neck (P=0.010) at 6 months. However, PLATE patients reported worse swallow function on Swallowing Quality of Life Questionnaire at 6 weeks (P=0.038). There were no differences in the rates of fusion, loss of disc height correction, subsidence, or in sagittal parameters between cohorts for both 1-level and 2-level ACDF.

CONCLUSION

There was greater incidence of transient postoperative dysphagia in both single and 2-level PLATE cohorts. However, early postoperative outcomes were worse for 2-level CAGE in certain patient-reported metrics. This suggests that although anterior instrumentation may be associated with a higher likelihood of dysphagia, it may also lead to higher short-term stability and improved patient-reported outcomes for 2-level fusion.

Two-year validation and minimal clinically important difference of the Veterans RAND 12 Item Health Survey Physical Component Score in patients undergoing minimally invasive transforaminal lumbar interbody fusion

OBJECTIVE

The Physical Component Score of the Veterans RAND 12 Item Health Survey (VR-12 PCS) has been assessed for use at short-term and intermediate-term time points for lumbar fusion populations. This study assesses the long-term validity and establishes minimal clinically important difference (MCID) values of VR-12 PCS in patients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS TLIF).

METHODS

A surgical registry was retrospectively reviewed for primary, elective, single-level MIS TLIF procedures with posterior instrumentation. Patients missing preoperative and 2-year postoperative VR-12 PCS survey data were excluded. VR-12 PCS, SF-12 Health Survey Physical Component Summary (SF-12 PCS), Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS PF), and Oswestry Disability Index (ODI) patient-reported outcome measures (PROMs) were recorded preoperatively and postoperatively. Responsiveness of the VR-12 measure was assessed in two ways. First, the mean postoperative PROM scores were compared with preoperative baseline values using a paired Student t-test. Second, MCID values were calculated using both distribution-based and anchor-based methods and used to assess improvement in VR-12 score at the 2-year time point. Discriminant validity of the VR-12 was assessed using cross-sectional and longitudinal anchors. Convergent validity of the VR-12 measure was assessed using Pearson's correlation coefficient and partial time-independent correlation. Floor and ceiling effects were assessed.

RESULTS

A total of 74 patients who underwent MIS TLIF were included. The VR-12 PCS demonstrated significant improvements at all time points from 12 weeks to 2 years (p < 0.001 for all). VR-12 PCSs were significantly different for patients classified using cross-sectional anchors (p < 0.001) and longitudinal anchors (p ≤ 0.005). Calculated MCID values ranged from 4.1 to 8.5, and 4.1 was selected as the optimal MCID, which 87.8% of patients achieved. Strong, significant correlations of the VR-12 PCS with SF-12 PCS and PROMIS PF were demonstrated at all time points (p < 0.001 for all). No significant floor or ceiling effects were detected.

CONCLUSIONS

The VR-12 PCS demonstrated excellent responsiveness, discriminant and convergent validity, and no significant floor or ceiling effects up to 2 years after MIS TLIF. Therefore, VR-12 PCS may serve as a valid measure of long-term physical function.

Obesity and Workers' Compensation in the Setting of Minimally Invasive Lumbar Decompression

OBJECTIVE

To investigate the influence of body mass index (BMI) on perioperative outcomes, postoperative patient-reported outcome measures (PROMs), and minimal clinically important difference (MCID) achievement among workers' compensation (WC) claimants undergoing minimally invasive lumbar decompression (MIS-LD).

METHODS

WC patients diagnosed with herniated nucleus pulposus undergoing single-level MIS-LD were identified. Patients were divided into 3 groups: Non-obese (<30 kg/m²), Obese I (≥30 and <35 kg/m²), and Obese II/III (≥35 kg/m²). PROMs were collected preoperatively and at 6 weeks, 12 weeks, 6 months, 1 year, and 2 years postoperatively. The predictive influence of BMI grouping on mean PROM scores was computed using simple linear regression. To compare PROMs between groups, post hoc pairwise comparisons of adjusted means were utilized. MCID achievement was compared between groups with χ² analysis.

RESULTS

A total of 81 patients were in the Non-obese cohort, and 43 and 45 in the Obese I and Obese II/III cohorts, respectively. Visual analog scale (VAS) leg, Oswestry Disability Index (ODI), and 12-Item Short Form Physical Composite Score (SF-12 PCS) were worse in the Obese I cohort at 12 weeks, and SF-12 PCS was lower in the Obese I vs. Obese II/III subgroup analysis (P ≤ 0.045, all). MCID achievement rates for ODI were higher for the Non-obese group at 12 weeks and overall (P ≤ 0.049, both). MCID attainment for VAS back was higher among the Non-obese cohort at 6-weeks (P = 0.022).

CONCLUSIONS

Patients with higher levels of obesity were more likely to experience longer length of stay and delayed discharge following MIS-LD. Increasing BMI was generally not a significant predictor of postoperative pain, disability, or physical health PROMs at most timepoints. MCID achievement rates for disability relief were significantly higher for non-obese patients.

The Worldwide Influence of Social Media on Cervical Spine Literature

BACKGROUND

The Altmetric (Digital Science, Holtzbrinck Publishing) Attention Score (AAS) is an automatically calculated score that accounts for other literary influences, which include academic sources as well as nonacademically focused social media outlets such as Twitter, Facebook, and news articles. This study compares the most popular cervical surgery articles on social media to the most cited articles within peer-reviewed literature and identifies journals that contribute the most articles and geographic trends.

METHODS

We searched the Altmetric database for cervical spine surgery articles since inception using the search phrase "cervical" and "spine." We ranked journals that contributed the most articles and calculated their AAS, contributing social media outlets (eg, Twitter, Facebook, News, etc) and citation counts. We also ranked the top 100 most popular cervical spine articles on social media and compared them to the most cited articles. Countries were assessed based on their mentions through the most contributing social media platform.

RESULTS

Of the 527 total journals identified in our search, the top 10 journals were responsible for contributing 60.2% of the total articles. The 3 journals that contributed the most articles were Spine (18.9%), European Spine Journal (11.8%), and The Spine Journal (10.3%). The journals with the highest AAS scores included Journal of Neurosurgery: Spine (11.3), Spine (8.8), and Journal of Manipulative & Physiological Therapeutics (5.8). Social media outlets that contributed the most mentions per article were Twitter (4.4), Facebook (0.5), and news sources (0.3). Among all countries contributing Twitter mentions, the 3 countries with the most cervical spine posts included the United States (23.3%), the United Kingdom (10.3%), and Spain (5.5%).

CONCLUSION

Our evaluation of cervical spine literature revealed Twitter, Facebook, and news sources are the most common social media outlets influencing title dissemination. Journals contributing the most articles did not necessarily have the highest average AAS.

CLINICAL RELEVANCE

Spinal surgeons should consider utilization of social media outlets, such as Twitter, Facebook, and news sources, to potentially increase the dissemination of their articles.

LEVEL OF EVIDENCE: 3

Spine Surgery Complications in the Ambulatory Surgical Center Setting: Systematic Review

STUDY DESIGN

This was a systematic review study.

PURPOSE

This study aims to review current literature to determine the rates of complications in relation to spine surgery in ambulatory surgery centers (ASC).

BACKGROUND

Recent improvements in anesthesia, surgical techniques, and technological advances have facilitated a rise in the use of ASC. Despite the benefits and lower costs associated with ASCs, there is inconsistent reporting of complication rates.

METHODS

This systematic review was completed utilizing the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Pertinent studies were identified through Embase and PubMed databases using the search string ((("ambulatory surgery center") AND "spine surgery") AND "complications"). Articles were excluded if they did not report outpatient surgery in an ASC, did not define complications, were in a language other than English, were non-human studies, or if the articles were classified as reviews, book chapters, single case reports, or small case series (≤10 patients). The primary outcome was the frequency of complications with respect to various categories.

RESULTS

Our query identified 150 articles. After filtering relevance by title, abstract, and full text, 22 articles were included. After accounting for 2 studies that were conducted on the same study sample, a total of 11,245 patients were analyzed in this study. The most recent study reported results from May 2019. While 5 studies did not list their surgical technique, studies reported techniques including open (6), minimally invasive surgery (2), endoscopic (4), microsurgery (1), and combined techniques (4). The following rates of complications were determined: cardiac 0.29% (3/1027), vascular 0.25% (18/7116), pulmonary 0.60% (11/1839), gastrointestinal 1.12% (2/179), musculoskeletal/spine/operative 0.59% (24/4053), urologic 0.80% (2/250), transient neurological 0.67% (31/4616), persistent neurological 0.61% (9/1479), pain related 0.57% (20/3479), and wound site 0.68% (28/4092).

CONCLUSIONS

After literature review, this is the first study to comprehensively analyze the current state of literature reporting on the complication profile of all ASC spine surgery procedures. The most common complications were gastrointestinal (1.12%) and the most infrequent were vascular (0.25%). Case reports varied significantly with regard to the type and rate of complications reported. This study provides complication profiles to assist surgeons in counseling patients on the most realistic expectations.

Systematic Review: Applications of Intraoperative Ultrasound in Spinal Surgery

BACKGROUND

Due to increased practicality and decreased costs and radiation, interest has risen for intraoperative ultrasound (iUS) in spinal surgery applications; however, few studies have provided a robust overview of its use in spinal surgery. We synthesize findings of existing literature on usage of iUS in navigation, pedicle screw placement, and identification of anatomy during spinal interventions.

METHODS

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were utilized in this systematic review. Studies were identified through PubMed, Scopus, and Google Scholar databases using the search string. Abstracts mentioning iUS in spine applications were included. Upon full-text review, exclusion criteria were implemented, including outdated studies or those with weak topic relevance or statistical power. Upon elimination of duplicates, multi-reviewer screening for eligibility, and citation search, 44 manuscripts were analyzed.

RESULTS

Navigation using iUS is safe, effective, and economical. iUS registration accuracy and success is within clinically acceptable limits for image-guided navigation (Table 2). Pedicle screw instrumentation with iUS is precise with a favorable safety profile (Table 2). Anatomical landmarks are reliably identified with iUS, and surgeons are overwhelmingly successful in neural or vascular tissue identification with iUS modalities including standard B mode, doppler, and contrast-enhanced ultrasound (CE-US) (Table 3). iUS use in traumatic reduction of fractures properly identifies anatomical structures, intervertebral disc space, and vasculature (Table 3).

CONCLUSION

iUS eliminates radiation, decreases costs, and provides sufficient accuracy and reliability in identification of anatomical and neurovascular structures in various spinal surgery settings.

Workers' Compensation Association With Clinical Outcomes After Anterior Cervical Diskectomy and Fusion

BACKGROUND

Research has suggested that workers' compensation (WC) status can result in poor outcomes after anterior cervical diskectomy and fusion (ACDF).

OBJECTIVE

To determine the influence WC status has on postoperative clinical outcomes after ACDF.

METHODS

A surgical database was reviewed for patients undergoing primary or revision single-level ACDF. Patients were grouped into WC vs Non-WC, and differences in baseline characteristics were assessed. Postoperative improvement was assessed for differences in mean scores between WC subgroups for visual analog scale (VAS) arm, VAS neck, 12-item Short Form Physical Composite Score, Patient-Reported Outcomes Measurement Information System physical function (PF), and Neck Disability Index (NDI) at preoperative and postoperative time points. Minimum clinically important difference (MCID) achievement was compared between groups.

RESULTS

The patient cohort included 44 with WC and 95 without. The cohort was 40% female with an average age of 48 years and mean body mass index of 30. Mean VAS arm, VAS neck, NDI, 12-item Short-Form Physical Composite Score, and Patient-Reported Outcomes Measurement Information System PF scores differed between groups; however, the difference was not sustained at the 1-yr time point. MCID achievement among WC subgroups was different for VAS arm (6 wk through 6 mo, P = .005), VAS neck (3 and 6 mo, P < .01), and NDI (3 and 6 mo, P < .05). No statistically significant difference was noted between cohorts for overall rates of MCID achievement for all patient-reported outcome measures collected.

CONCLUSION

WC patients reported similar preoperative and 1-yr postoperative neck and arm pain compared with non-WC patients after ACDF. One-yr MCID achievement rates were similar between cohorts for disability and PF scores.

Failure in cervical total disc arthroplasty: single institution experience, systematic review of the literature, and proposal of the RUSH TDA failure classification system

BACKGROUND CONTEXT

Cervical total disc arthroplasty (TDA) is an alternative procedure to anterior cervical discectomy and fusion that facilitates neural decompression while both preserving motion of the spinal unit and decreasing the risk for degenerative changes at adjacent segments. However, due to its more recent introduction in clinical practice and low complication rates, the modes by which TDA may fail remain to be described.

PURPOSE

This study sought to identify the modes and frequencies of cervical TDA failure in order to propose a novel classification system.

STUDY DESIGN

Retrospective cohort and systematic review.

PATIENT SAMPLE

Patients who underwent single or two-level TDA for cervical radiculopathy or myelopathy at a single institution and in the literature of medium and large prospective studies.

OUTCOME MEASURES

Cervical TDA failure, defined as subsequent surgical intervention at the index segment.

METHODS

This study retrospectively reviewed patients who underwent single or two-level TDA for cervical radiculopathy or myelopathy at a single institution to identify the potential implant failure modes. A systematic review and meta-analysis of prospective data in the literature was then performed to further supplement failure mode identification and to describe the rates at which the various failure types occurred. Statistical analysis included between-group comparisons of Non-Failed and Failed patients and frequencies of each failure type among Failed patients.

RESULTS

A retrospective review at our institution of 169 patients (201 levels) identified eight failures, for a failure rate of 4.7%. Additionally, seven patients were revised who had the primary surgery at an outside institution. The systematic review of 3976 patients (4525 levels) identified 165 (4.1%) additional failures. Using this data, six primary failure types were classified, with several subtypes. These include recurrent or persistent index-level stenosis (Type I); migration (Type II) presenting as gross extrusion (A) or endplate failure with subsidence/acute fracture (B); instability (Type III) due to mechanical loosening (A), septic loosening (B), or device fracture (C); device motion loss (Type IV) such as "locking" of the device in kyphosis; implantation error (Type V) due to malposition (A) or improper sizing (B); and wear (Type VI) either without osteolysis (A) or with wear-particle-induced osteolysis (B). Stenosis (Type I) was the most common mode of failure found both through retrospective review and in the literature.

CONCLUSIONS

Cervical TDA fails through six primary mechanisms. While rates of certain failures requiring subsequent surgical intervention are low, it is possible that these complications may become more prevalent upon further longitudinal observation. Thus, future application and validation of this classification system is warranted to evaluate how failure frequencies change over time and with larger patient samples.

Risk Factors for Failing to Reach a Minimal Clinically Important Difference Following Minimally Invasive Lumbar Decompression

BACKGROUND

Clinically important postoperative changes can be best evaluated through the minimal clinically important difference (MCID). Our study aims to evaluate risk factors associated with failure to achieve MCID following lumbar decompression (LD).

METHODS

Demographics, perioperative characteristics, and patient-reported outcome measures (PROM) for pain, disability, and physical function were retrospectively reviewed and collected for patients undergoing LD. MCID achievement was calculated using established values. Relative risk of demographic and perioperative characteristics with failure to meet MCID for all PROMs was calculated. Least absolute shrinkage and selection operator (LASSO) was used to estimate individual risk factors, and postestimation logistic regression was performed.

RESULTS

The study cohort included 811 patients. Comorbidity burden was associated with failed MCID for visual analog scale (VAS) back and leg pain and Oswestry Disability Index (ODI). Operative levels or duration was associated with failed MCID for VAS leg pain, 12-item short form physical component summary (SF-12 PCS), and the patient-reported outcomes measurement information system physical function (PROMIS PF). Preoperative spinal pathology was associated with failed MCID for VAS leg pain, ODI, SF-12 PCS, and PROMIS PF. Additional risk factors included the type of operation, insurance, age, and body mass index. LASSO selected insurance, age, comorbidity burden, blood loss, operative duration, and type of spinal pathology as significant risk factors for failure to reach MCID.

CONCLUSION

Failure to reach MCID was greatest for VAS back. Age, comorbidity burden, and prolonged procedures were significantly associated with risk for failure to reach MCID for a majority of PROMs. Comorbidity burden combined with operative outcomes may place patients at increased risk for failure to reach MCID for pain, disability, and physical function following LD.

LEVEL OF EVIDENCE

4.

CLINICAL RELEVANCE

Establishes risk factors for failing to reach the threshold of meaningful difference in symptoms after LD surgery.