Anterior Cervical Discectomy and Fusion Versus Cervical Disc Replacement for a Workers' Compensation Population in an Ambulatory Surgical Center.

STUDY DESIGN: Retrospective Cohort. OBJECTIVE: To evaluate patient-reported outcome measures (PROM) and minimal clinically important difference (MCID) achievement outcomes between anterior cervical discectomy and fusion (ACDF) and cervical disk replacement (CDR) in the Workers' Compensation (WC) population. SUMMARY OF BACKGROUND DATA: No studies to our knowledge have compared PROMs and MCID attainment between ACDF and CDR among patients with WC insurance undergoing surgery in an outpatient ambulatory surgical center (ASC). METHODS: WC insurance patients undergoing primary, single/double-level ACDF/CDR in an ASC were identified. Patients were divided into ACDF versus CDR. PROMs were collected at preoperative/6-week/12-week/6-month/1-year timepoints, including PROMIS-PF, SF-12 PCS/MCS, VAS neck/arm, and NDI. RESULTS: Seventy-nine patients were included, 51 ACDF/28 CDR. While operative time (56.4 vs. 54.4 min), estimated blood loss (29.2 vs. 25.9 mL), POD0 pain (4.9 vs. 3.8), and POD0 narcotic consumption (21.2 vs. 14.5 oral morphine equivalents) were higher in ACDF patients, none reached statistical significance ( P >0.050, all). One-year arthrodesis rate was 100.0% among ACDF recipients with available imaging (n=36). ACDF cohort improved from preoperative for PROMIS-PF from 12 weeks to 1 year, SF-12 PCS at 6 months, all timepoints for VAS neck/arm, and 12 weeks/6 months for NDI ( P ≤0.044, all). CDR cohort improved from preoperative for PROMIS-PF at 6 months, VAS neck/arm from 12 weeks to 1 year, and NDI at 12 weeks/6 months ( P ≤0.049, all). CDR cohort reported significantly lower VAS neck at 12 weeks/1 year and VAS arm at 12 weeks ( P ≤0.039, all). MCID achievement rates did not differ. CONCLUSION: While operative duration/estimated blood loss/acute postoperative pain/narcotic consumption were, on average, higher among ACDF recipients, these were not statistically significant, possibly due to the limited sample size. ACDF and CDR ASC patients generally demonstrated comparable arm pain/disability/physical function/mental health, though neck pain was significantly lower at multiple timepoints among CDR patients. Clinically meaningful PROM improvements were comparable. Larger, multicentered studies are required to confirm our results.

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. METHODS: Primary, single-level/multilevel minimally invasive lumbar decompression was identified. Patient-reported outcome measures (PROMs) collected preoperatively/postoperatively included visual analog scale back/leg, Oswestry Disability Index, 9-Item Patient Health Questionnaire (PHQ-9), and 12-Item Short Form Mental Composite Score (SF-12 MCS). Patients rated current satisfaction level (0-10) with back/leg pain and disability. A 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 analysis of variance compared patient satisfaction with back/leg pain and disability among PHQ-9 subgroups. The Student's t-test for independent samples compared patient satisfaction between SF-12 MCS subgroups. Analysis of covariance (ANCOVA) assessed differences in satisfaction between depression subgroups while controlling for preoperative/postoperative 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 at 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 at 2 years (P < 0.001), leg pain at 12 weeks/1 year/2 years (P ≤ 0.047, all), and disability at 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 at 2 years (P ≤ 0.001, both). CONCLUSIONS: 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 outcomes.

Influence of Predominant Neck versus Arm Pain on Anterior Cervical Discectomy and Fusion Outcomes: A Follow-Up Study.

OBJECTIVE: To assess differences in postoperative patient-reported outcome measures (PROMs) and minimal clinically important difference (MCID) attainment following single-level anterior cervical discectomy and fusion based on predominant preoperative pain symptom. METHODS: Patients undergoing primary, single-level anterior cervical discectomy and fusion were identified. PROMs included visual analog scale (VAS) arm and neck, 12-item short-form physical component summary (SF-12 PCS), Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS-PF), and Neck Disability Index, collected preoperatively and postoperatively. Patients were placed in preoperative predominant arm pain (pAP) and preoperative predominant neck pain groups. χ2 test compared demographic and perioperative characteristics, and MCID attainment rates. Student t test evaluated change from preoperative to postoperative PROM values and compared PROMs between groups. RESULTS: There were 110 patients assessed (52 neck pain, 58 arm pain). Patients with preoperative predominant neck pain improved significantly from preoperative to postoperative at 12 weeks to 1 year for PROMIS-PF, 6 months and 1 year for SF-12 PCS, 6 weeks to 1 year for VAS neck, 6 weeks to 6 months for VAS arm, and 6 weeks to 2 years for Neck Disability Index (all P ≤ 0.035). Patients with pAP improved significantly from preoperative to all postoperative time points for PROMIS-PF, 6 months to 2 years for SF-12 PCS, 6 weeks to 1 year for VAS neck, 6 weeks to 1 year for VAS arm, and 6 weeks to 6 months for Neck Disability Index (all P ≤ 0.040). Mean PROMIS-PF was higher at 6 weeks, preoperative VAS neck was lower, and preoperative VAS arm was higher for pAP patients (all P ≤ 0.013). MCID attainment was significantly higher in pAP patients for PROMIS-PF from 6 weeks to 6 months, SF-12 PCS 6 weeks, and VAS arm 12 weeks. CONCLUSIONS: Predominant pain symptom demonstrated little effect on perioperative characteristics and postoperative PROMs. Anterior cervical discectomy and fusion candidates will likely experience similar clinically meaningful postoperative improvements in physical function, disability, and pain.

Impact of Surgeon Experience on Outcomes of Anterior Cervical Discectomy and Fusion.

INTRODUCTION: The relationship between surgeon experience and cervical fusion outcomes has yet to be assessed. We investigate perioperative characteristics, patient-reported outcomes (PROMs), and minimal clinically important difference (MCID) achievement after anterior cervical diskectomy and fusion (ACDF) by the volume of cases done throughout an orthopaedic spine surgeon's career. METHODS: ACDF procedures between 2005 and 2020 were identified. Group I included the first half of ACDF cases (#1-#321). PROMs were introduced in the second half of the ACDF cases; thus, the next 322 cases were subdivided to compare PROM and MCID between subgroups (cases #322 to #483 = group II and #484 to #645 = group III). PROMs, including VAS back/leg, Oswestry Disability Index (ODI), Short Form-12 Physical Composite Score, and PROMIS-PF, were collected preoperatively/postoperatively. Demographics, perioperative variables, mean PROMs, and MCID achievement were compared between groups and subgroups using the Student t-test and chi-square. Logistic regression evaluated MCID achievement using the established threshold values. RESULTS: A total of 642 patients were included (320 in group I, 161 in group II, and 161 in group III). The latter cases had significantly decreased surgical time, blood loss, and postoperative length of stay in comparison of groups and subgroups (P ≤ 0.002, all). CT-confirmed 1-year arthrodesis rates were increased among the latter cases (P = 0.045). Group II had significantly higher arthrodesis rates than group III (P = 0.039). The postoperative complication rates were lower in the latter cases (P < 0.001, all), whereas subgroup analysis revealed lower incidence of urinary retention and other complications in group III (P ≤ 0.031, all). Mean PROMs were significantly inferior in group II versus group III for VAS neck at 6 months (P = 0.030), Neck Disability Index at 6 months preoperatively (P ≤ 0.022, both), Short Form-12 Physical Composite Score at 12 weeks/2 years (P ≤ 0.047, both), and PROMIS-PF at 12 weeks/6 months (P ≤ 0.036, both). The MCID attainment rates were higher among group III for VAS neck/Neck Disability Index at 2 years (P ≤ 0.005) and overall achievement across all PROMs (P ≤ 0.015, all). DISCUSSION: Increased ACDF case volume may lead to markedly decreased surgical time, blood loss, and length of postoperative stay as well as improved clinical outcomes in pain, disability, and physical function.

Characterizing the host response to rhPDGF-BB in a rat spinal arthrodesis model.

BACKGROUND: Due to the constraints surrounding autograft bone, surgeons have turned to osteoinductive agents to augment spinal fusion. Reports of complications and questionable efficacy slowed the adoption of these alternatives. Recombinant human platelet-derived growth factor B homodimer (rhPDGF-BB) has been Food and Drug Administration (FDA)-approved (Augment) to promote fusion in other areas of orthopedics, but its characterization in spine fusion has not yet been tested. The purpose of this study is to characterize the host response to PDGF-BB in vivo. METHODS: Eighty female Fischer rats underwent L4-5 posterolateral fusion using one of four implant types: (a) iliac crest syngeneic allograft harvested from syngeneic donors, (b) ß-TCP/bovine collagen matrix (ß-TCP/Col) with sodium acetate buffer, (c) ß-TCP/Col with 0.3 mg/mL "low dose," or (d) ß-TCP/Col with 3.0 mg/mL "high dose" of rhPDGF-BB. Animals underwent magnetic resonance imaging (MRI) and serum cytokine quantification at 4, 7, 10, and 21 days, postoperatively. Tissues were processed for immunofluorescence staining for Ki67 and von Willebrand factor (vWF) to assess neovascularization. RESULTS: MRI demonstrated no differences in fluid accumulation among the four treatment groups at any of the time points. Serum cytokine analysis showed no clinically significant differences between treatment groups in 20 of the 27 cytokines. Inflammatory cytokines IFN-γ, IL-1ß, IL-18, MCP-1, MIP-1α, TNF-α were not induced by rhPDGF-BB. Histology showed no differences in cell infiltration, and Ki67 and vWF immunofluorescence staining was similar among groups. CONCLUSIONS: rhPDGF-BB delivered with a ß-TCP/Col matrix exerts no exaggerated systemic or local host inflammatory response when compared to iliac crest syngeneic allograft bone or the control carrier. rhPDGF-BB mixed with a ß-TCP/Col matrix could be a viable and safe biologic alternative to syngeneic allograft in spine fusion. Further studies need to be performed to evaluate efficacy in this setting.

Stem Cells and Spinal Fusion.

There are a number of bone regeneration therapeutics available to aid spinal fusion; however, many are associated with pseudarthrosis, inflammation, and other complications. Mesenchymal stem cells for fusion has been promoted to mitigate these risks and achieve successful bony fusion. This article reviews the clinical studies available with use in spinal fusion. Preliminary results demonstrate that stem cells can provide high rates of fusion, comparable to autograft, without associated morbidity. Autologous and allogeneic stem cell sources showed similar rates of fusion in this review. Further research is required to evaluate which clinical situations are the optimum for stem cell use.