Faculty Bibliography

BACKGROUND:Lumbar herniated nucleus pulposus (HNP) is a common spinal pathology often treated by microscopic lumbar discectomy (MLD), though prior reports have not demonstrated which preoperative MRI factors may contribute to significant clinical improvement after MLD. PURPOSE/OBJECTIVE:To analyze the MRI characteristics in patients with HNP that predict meaningful clinical improvement in Health Related Quality of Life scores (HRQoL) after MLD. STUDY DESIGN/SETTING/METHODS:Retrospective clinical and radiological study of patients undergoing MLD for HNP at a single institution over a two-year period. PATIENT SAMPLE/METHODS:88 patients receiving MLD treatment for HNP. OUTCOME MEASURES/METHODS:Cephalocaudal Canal Migration; Canal & HNP Anterior-Posterior (AP) Lengths and Ratio; Canal & HNP Axial Areas and Ratio; Hemi-Canal & Hemi-HNP Axial Areas and Ratio; Disc appearance (black, grey or mixed), Baseline (BL) and 3-Month (3M) postoperative Health Related Quality of Life Scores. METHODS:Patients > 18 years old who received MLD for HNP with BL and 3M HRQoL scores of PROMIS (Physical Function, Pain Interference, and Pain Intensity), ODI, VAS Back, and VAS Leg scores were included. HNP and spinal canal measurements of cephalocaudal migration, AP length, area, hemi-area, and disc appearance were performed using T2 axial and sagittal MRI. HNP measurements were divided by corresponding canal measurements to calculate AP, Area, and Hemi-Area ratios. Using known minimal clinically important differences (MCID) for each ΔHRQoL score, patients were separated into two groups based on whether they reached MCID (MCID+) or did not reach MCID (MCID-). The MCID for PROMIS Pain Intensity was calculated using a decision tree. A linear regression illustrated correlations between PROMIS vs ODI and VAS Back/Leg scores. Independent t-tests and chi [2] tests were utilized to investigate significant differences in HNP measurements between the MCID+ and MCID- groups. RESULTS:± 43.2, p<.04). MCID+ patients had a greater Hemi-Area Ratio than MCID- patients had in 4 out of 6 HRQoL score comparisons (51.8% ± 14.7 vs 43.9% ± 14.9, p<.05). CONCLUSIONS:Patients who met MCID after MLD had larger HNP areas and larger Hemi-HNP Areas than those who did not meet MCID. These patients were also 2.7x more likely to have a grey MRI signal than a mixed or black MRI signal. When accounting for HNP area relative to canal area, patients who met MCID had greater Hemi-HNP canal occupation than patients who did not meet MCID. The results of this study suggest that preoperative MRI parameters can be useful in predicting patient reported improvement after MLD.

Study Design/UNASSIGNED:Retrospective cohort study. Objective/UNASSIGNED:To investigate radiological differences in lumbar disc herniations (herniated nucleus pulposus [HNP]) between patients receiving microscopic lumbar discectomy (MLD) and nonoperative patients. Methods/UNASSIGNED:test and chi-square analyses compared differences in the groups, binary logistic regression analysis determined odds ratios (ORs), and decision tree analysis compared the cutoff values for risk factors. Results/UNASSIGNED:< .01). Conclusion/UNASSIGNED:Patients who underwent MLD treatment had significantly different axial HNP area, frequency of caudal migration, magnitude of cephalad/caudal migration, and disc herniation MRI signal compared to patients with nonoperative treatment.

Previous efforts to evaluate the detection of human papilloma viral (HPV) DNA in whole saliva as a diagnostic measure for HPV-associated oropharyngeal cancer (HPV-OPC) have not shown sufficient clinical performance. We hypothesize that salivary exosomes are packaged with HPV-associated biomarkers, and efficient enrichment of salivary exosomes through isolation can enhance diagnostic and prognostic performance for HPV-OPC. In this study, an acoustofluidic (the fusion of acoustics and microfluidics) platform was developed to perform size-based isolation of salivary exosomes. These data showed that this platform is capable of consistently isolating exosomes from saliva samples, regardless of viscosity variation and collection method. Compared with the current gold standard, differential centrifugation, droplet digital RT-PCR analysis showed that the average yield of salivary exosomal small RNA from the acoustofluidic platform is 15 times higher. With this high-yield exosome isolation platform, we show that HPV16 DNA could be detected in isolated exosomes from the saliva of HPV-associated OPC patients at 80% concordance with tissues/biopsies positive for HPV16. Overall, these data demonstrated that the acoustofluidic platform can achieve high-purity and high-yield salivary exosome isolation for downstream salivary exosome-based liquid biopsy applications. Additionally, HPV16 DNA sequences in HPV-OPC patients are packaged in salivary exosomes and their isolation will enhance the detection of HPV16 DNA.

War has historically been a major catalyst for advancement in military medical care and medicine in general. In our current conflicts, advances in battlefield medicine, evacuation techniques, and personal protective equipment have improved survival rates among members of the armed services. With increased survival, there has been increased prevalence of serious but nonfatal injuries, particularly from blunt and penetrating trauma. Blast injuries are the major cause of trauma and have both blunt and penetrating components. With respect to the spine, blasts have led to open, contaminated wounds that are complex and difficult to treat. Additionally, blasts have led to an increased incidence of lower lumbar burst fractures and lumbosacral dissociation. As these and other injuries are being seen more commonly during war, we must ensure that our military medical system is adapting to ensure we are taking care of our military personnel at the highest level.

Background/UNASSIGNED:Robotic-guided navigation systems for pedicle screw placement has gained recent interest to ensure accuracy and safety and diminish radiation exposure. There have been no published studies using a new combined robotics and navigation system (Globus ExcelsiusGPS system). The purpose of this study was to demonstrate safety with this system. Methods/UNASSIGNED:This is a case series of consecutive patients at a single institution from February 1, 2018, to August 31, 2018. All patients who had planned placement of thoracic and lumbar pedicle screws using the combined robotics-navigation system were included. Chart review was performed for operative details. A subgroup analysis was performed on patients with postoperative computed tomography (CT) scans to assess screw placement accuracy using the Gertzbein and Robbins system. Acceptable pedicle screw position was defined as grade A or B. Results/UNASSIGNED:One hundred six patients were included, with 636 pedicle screws, 6 iliac screws, and 1 S2AI screw. Five cases were aborted for technical issues. In the remaining 101 patients, 88 patients had screws placed using preoperative CT planning and 13 patients using intraoperative fluoroscopy planning. All screws except for 5 pedicle screws in 2 patients were placed successfully using the robot (99%). These 5 pedicle screws were placed by converting to a fluoro-guided technique without robotic assistance. Eighty-six patients had screws placed using a percutaneous technique, and 15 patients had screws placed using an open technique. Ninety-eight patients underwent interbody placement: 28 anterior lumbar interbody fusions (ALIFs), 12 lateral lumbar interbody fusions (LLIFs), and 58 transforaminal lumbar interbody fusions (TLIFs). All ALIFs and LLIFs were performed prior to placement of the screws. Four LIF patients had screws placed in the lateral position. No patients had screw-related complications intraoperatively or postoperatively, and no patients returned to the operating room for screw revision. Thirteen patients underwent postoperative CT for various reasons. Of the 66 pedicle screws that were examined with postoperative CT, all screws (100%) had acceptable position. Conclusion/UNASSIGNED:This study demonstrates that the combined robotics and navigation system is a novel technology that can be utilized to place pedicle screws and pelvic screws safely and has the potential to reduce screw-related complications. Level of Evidence/UNASSIGNED:4 (case series).

BACKGROUND CONTEXT: Lumbar herniated nucleus pulposus (HNP) is a common spinal pathology often treated by microscopic lumbar discectomy (MLD), though prior reports have not demonstrated which preoperative MRI factors may contribute to significant clinical improvement after MLD. PURPOSE: To analyze the MRI characteristics in patients with HNP that predict meaningful clinical improvement in Health Related Quality of Life scores (HRQL) after MLD. STUDY DESIGN/SETTING: Retrospective clinical and radiological study of patients undergoing MLD for HNP at a single institution over a two year period of time. PATIENT SAMPLE: Eighty-eight patients receiving MLD treatment for HNP. OUTCOME MEASURES: Cephalocaudal canal migration; canal & HNP anterior-posterior (AP) lengths and ratio; canal & HNP axial areas and ratio; hemi-canal & hemi-HNP axial areas and ratio; disc appearance (black, grey or mixed), baseline (BL) and 3-month (3M) postoperative HRQL scores.
METHOD(S): Patients >18 years old who received MLD for HNP with BL and 3M HRQL scores of PROMIS (Physical Function, Pain Interference, and Pain Intensity), ODI, VAS Back, and VAS Leg scores were included. HNP and spinal canal measurements of cephalocaudal migration, AP length, area, hemi-area, and disc appearance were performed using T2 axial and sagittal MRI. HNP measurements were divided by corresponding canal measurements to calculate AP, Area, and Hemi-Area ratios. Using known minimal clinically importance differences (MCID) for each DELTAHRQoL score, patients were separated into two groups based on whether they reached MCID (+) or did not reach MCID (-). The MCID for Pain Intensity was calculated using a decision tree. A linear regression illustrated correlations between PROMIS vs ODI and VAS Back/Leg scores. Independent t-tests and chi-square tests were utilized to investigate significant differences in HNP measurements between the (+) and (-) MCID groups.
RESULT(S): Eighty-eight MLD patients were included (age=44.6+/-14.9, 38.6% female). Pain Interference and pain intensity were strongly correlated with ODI and VAS Back/Leg (R>=.505), and physical function was significantly correlated with ODI and VAS Back/Leg (R=-.349) (all p<.01). The strongest MRI predictors of meeting HRQL MCID were grey disc appearance, HNP area (>116.6 mm²), hemi-HNP Area (>84.6 mm²), and Hemi-Area Ratio (>51.8%); (+) patients were 2.7 times more likely to have a grey HNP than (-) patients in 5 out of 6 HRQL score comparisons (p<.025). Also, (+) patients had larger HNP areas than (-) patients had in 5 out of 6 HRQoL score comparisons (116.6 mm² +/- 46.4 vs 90.0 mm² +/- 43.2, p<.04), and had larger hemi-HNP areas than (-) patients had in 4 out of 6 HRQL score comparisons (84.6 mm² +/- 38.8 vs 66.3 mm² +/- 29.7, p<.04). (+) patients had a greater hemi-area ratio than (-) patients had in 4 out of 6 HRQL score comparisons (51.8% +/- 14.7 vs 43.9% +/- 14.9, p<.05).
CONCLUSION(S): Patients who met MCID after MLD had larger HNP areas by 26.6 mm² and larger hemi-HNP areas by 18.3 mm² than those who did not meet MCID. These patients were also 2.7x more likely to have a grey HNP compared to patients who did not meet MCID. When accounting for HNP area relative to canal area, patients who met MCID had a 7.9% greater Hemi-HNP canal occupation than patients who did not meet MCID. The results of this study suggest that preoperative MRI parameters can be useful in predicting patient reported improvement after MLD. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: T1 slope (T1S) is a parameter typically discussed in the context of cervical deformity and is correlated with health-related quality of life outcomes. Although prior research has suggested that T1S is related to global alignment, a definition for "high" T1S has not been established. Most patients undergoing cervical surgery do not receive full spine imaging. Therefore, it would be beneficial to have a parameter obtained from cervical radiographs that is associated with thoracolumbar malalignment. PURPOSE: To define a threshold for T1S that is associated with thoracolumbar malalignment STUDY DESIGN/SETTING: Retrospective review of a prospective adult spinal deformity(ASD) database PATIENT SAMPLE: A total of 226 preoperative ASD patients. OUTCOME MEASURES: Baseline sagittal alignment: T1S, thoracic kyphosis(TK), C7 sagittal vertical axis (SVA), T1 pelvic angle (TPA), pelvic tilt (PT), pelvic incidence-lumbar lordosis mismatch (PI-LL).
METHOD(S): A database of preoperative ASD patients was analyzed. Patients without preoperative full-spine images were excluded. Measures obtained from standing lateral radiographs included: T1S, TK, SVA, TPA, PT, and PI-LL. T1S was correlated to each of these parameters. Decision tree analysis was then used to determine the T1S corresponding to published thresholds for high TK (40degree), SVA (40mm), TPA (25degree), and PT (25.degree). Alignment between high and normal T1S patients was compared via t-tests and chi-square tests.
RESULT(S): A total of 226 preoperative ASD patients were included (mean 58+/-16y 62% F). At baseline, 30% had high TK, 54% had high SVA, 46% had high TPA, and 46% had high PT. Larger T1S was significantly correlated with greater SVA (R=.365) TPA (R=.302), TK (R=.606), and PT (R=.230)(all p<.001). Decision tree analysis yielded a threshold of 30degree for high T1S, which 50% of patients had. Compared to patients with T1S<30degree, those with T1S>30degree had higher TK (41.5degree vs 25.8degree), SVA (78.7mm vs 33.7mm), TPA (27.6degree vs 18.3degree), and PT (26.3degree vs 20.8degree), and PI-LL (18.2degree vs 11.7degree)(all p<0.05). Seventy-nine percent of patients with high T1S had high TK (T1S<30= 13%), 69% had high SVA (T1S<30=38%), 66% had high TPA (T1S<30= 37%), 60% had PT>25degree (T1S<30= 42%), and 47% had PI-LL>20degree (T1S<30= 34%) (all p<.05). T1S was not associated with PI.
CONCLUSION(S): Similar to previous studies higher T1S was associated with worse global alignment. T1S was most strongly associated with TK. A T1S=30degree corresponds to thresholds for high TK, SVA, TPA, and PT. Therefore, surgeons should consider obtaining full-spine radiographs if a T1S>30degree is present on cervical imaging. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Existing health outcome (HRQL) metrics do not adequately capture disability from cervical deformity (CD) and do not correlate with cervical malalignment. In the novel Patient Generated Index (PGI) patients report their greatest difficulties related to their CD. These results were used to determine items that should be included in a CD-specific HRQL. PURPOSE: To utilize the PGI to reveal the aspects of CD disability not captured by existing HRQLs. STUDY DESIGN/SETTING: Retrospective review of a prospective CD database. PATIENT SAMPLE: A total of 45 CD patients. OUTCOME MEASURES: HRQL metrics: PGI, NDI, mJOA, EQ-5D.
METHOD(S): CD patients completed the PGI by describing aspects of their disability that bother them the most. The responses were weighted and scored. PGI responses were categorized into domains: Sagittal discomfort/range of motion (ROM), Activities of Daily Living (ADL), and Social Life/Hobbies. PGI scores and legacy HRQL metrics were correlated with alignment, pain, age, sex, BMI, and medical comorbidities. R2 values are reported for linear regression models that include the drivers significantly associated with each HRQL metric.
RESULT(S): Forty-five CD patients (mean cSVA: 51mm) including 12 PGI patients (mean cSVA: 62mm) were included for analysis. PGI scores were found to be driven significantly by age and C2 Slope (r2=0.50). NDI was driven significantly by neck pain, back pain, and BMI (r2=0.32). mJOA was driven significantly by Charlson Comorbidity Score, back pain and weight (r2=0.33). EQ5D was significantly driven by CBVA, age and T1 Slope (r2=0.78). When examining PGI domains, Sagittal Discomfort/ROM score was driven significantly by cSVA and age (r2=0.54). ADL score was driven by CBVA and a medical history of neuromuscular disease (r2=0.87). Social Life/Hobbies score was driven by Charlson Comorbidity Scores, a medical history of ankylosing spondylitis, and a medical history of connective tissue disease (r2=1.0). Horizontal Gaze/Walking Safety, Pain, and Neurologic Complaints did not correlate significantly with alignment, pain, demographic info or past medical history.
CONCLUSION(S): Legacy HRQLs do not adequately capture CD disability and do not correlate with cervical malalignment. In a CD cohort, PGI scores and EQ5D scores were driven significantly by sagittal alignment. However, mJOA and NDI were driven by pain and medical comorbidities. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT/BACKGROUND:Lumbar disc herniation and retrolisthesis have been shown to be significant degenerative changes that can be associated with back pain. Current literature has shown evidence that retrolisthesis is associated with similar baseline function in patients with L5-S1 disc herniation, but worse post-operative outcomes 2 years after lumbar discectomy. However, literature comparing long-term post-operative outcomes at 8-year follow-up in patients with L5-S1 disc herniation with retrolisthesis is lacking. PURPOSE/OBJECTIVE:The purpose of the present study is to compare long-term post-operative outcomes at 8-year follow-up in patients with retrolisthesis and L5-S1 disc herniations to patients with L5-S1 disc herniations without retrolisthesis. STUDY DESIGN/METHODS:Retrospective review of prospectively collected data from the Spine Patients Outcomes Research Trial (SPORT) database. PATIENT SAMPLE/METHODS:Sixty-five patients who underwent lumbar discectomy for L5-S1 disc herniations with 8-year follow-up from the SPORT. OUTCOME MEASURES/METHODS:Short Form (SF)-36 bodily pain scale, SF-36 physical function scale, Oswestry Disability Index (ODI), Sciatica Bothersomeness Index (SBI), and reoperation rate. METHODS:Baseline surgical parameters, length of stay, complication rates, re-operation rates, and outcome measures were recorded in the SPORT database. Follow-up data was collected at 6 weeks, 3 months, 6 months, 1 year, 2 years, 3 years, 4 years, 5 years, 6 years, 7 years, and 8 years. Retrolisthesis was defined as posterior subluxation ≥ 8%. Patients with and without retrolisthesis were compared using a mixed-effects model of longitudinal regression. Outcomes were calculated as time-weighted averages over 8 years. Reoperation rates were compared using the log-rank test based on time to first reoperation. RESULTS:One hundred-twenty five patients met inclusion criteria for the present study, including 29 patients with retrolisthesis (23.3%) and 96 patients who did not have retrolisthesis (76.7%). The greatest difference in clinical outcome measures was found at 2 years post-operatively. This was the only point at which both the SF-36 BP and PF showed significant differences between the retrolisthesis and non-retrolisthesis group. At 3 years, SF-36 BP was significantly lower in patients with retrolisthesis (39.9 vs 52, p=0.046). At 8-year follow-up, the presence of retrolisthesis in patients undergoing L5-S1 discectomy was not associated with worse outcome measure scores based on the AUC analysis for any metric investigated (SF-36 BP 41.4 vs 47.1, p=0.18; SF-36 PF 38.9 vs 45.4, p=0.12; ODI -39.4 vs -34.8, p=0.23; -11.6 vs -10.4, p=0.25) or a difference in reoperation rate (retrolisthesis group 10%, non-retrolisthesis group 17%, p=0.41). CONCLUSIONS:While retrolisthesis can contribute to low back pain and dysfunction in patients undergoing lumbar discectomy for L5-S1 herniated nucleus pulposus in early follow-up, no significant difference was found in post-operative outcomes after 3 years. Additionally, retrolisthesis was not found to be associated with different reoperation rates at 8 years postoperatively.