Faculty Bibliography

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: 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/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.

Cancer, a local disease at an early stage, systemically evolves as it progresses by triggering alterations in surrounding microenvironment, disturbing immune surveillance and further disseminating its molecular contents into circulation. This pathogenic characteristic of cancer makes the use of biofluids such as blood/serum/plasma, urine, tear and cerebrospinal fluids credible surrogates harboring tumor tissue-derived molecular alterations for the detection of cancer. Most importantly, a number of recent reports have credentialed the clinical validity of saliva for the detection of systemic diseases including cancers. In this review, we discussed the validity of saliva as credible biofluid and clinical sample type for the detection of cancers. We have presented the molecular constituents of saliva that could mirror the systemic status of our body and recent findings of salivaomics associated with cancers. Recently, liquid biopsy to detect cancer-derived circulating tumor DNA has emerged as a credible cancer-detection tool with potential benefits in screening, diagnosis and also risk management of cancers. We have further presented the clinical validity of saliva for liquid biopsy of cancers and a new technology platform based on electrochemical detection of cancer-derived ctDNA in saliva with superior sensitivity and point-of-care potential. The clinical utilities of saliva for the detection of cancers have been evidenced, but biological underpinning on the existence of molecular signatures of cancer-origin in saliva, such as via exosomal distribution, should be addressed in detail.

Previously, we detected circulating tumor DNA that contained two EGFR mutations (p.L858R and exon19 del) in plasma of patients with late-stage non-small-cell lung carcinoma (NSCLC) using the electric field-induced release and measurement (EFIRM) platform. Our aim was to determine whether EFIRM technology can detect these mutations in patients with early-stage NSCLC. Prospectively, 248 patients with radiographically determined pulmonary nodules were recruited. Plasma was collected before biopsy and histologic examination of the nodule. Inclusion criteria were histologic diagnosis of benign nodule (control) and stage I or II adenocarcinoma harboring either p.L858R or exon19 delEGFR mutations. Plasma samples were available from 44 patients: 23 with biopsy-proven benign pulmonary nodules and 21 with stage I or II adenocarcinoma (12 p.L858R and 9 exon19 delEGFR variants). Samples were analyzed for the EGFR mutations using the EFIRM platform. Assay sensitivity was 92% for p.L858R (11 of 12 samples positive) and 77% for exon19 del (7 of 9 samples positive). Specificity was 91% with two false-positive results in 23 patients with EGFR-positive nodules and 95% for the entire 44-patient series. Concordance was 100% with identical mutations discovered in plasma and nodule biopsy. The EFIRM platform is able to noninvasively detect two EGFR mutations in individuals with early-stage NSCLC.

STUDY DESIGN/METHODS:Cross-Sectional Study. OBJECTIVE:The goal of this study is to investigate how surgeons differ in collar and narcotic use, as well as return to driving recommendations following cervical spine surgeries and the associated medico-legal ramifications of these conditions. SUMMARY OF BACKGROUND DATA/BACKGROUND:Restoration of quality of life is one of the main goals of cervical spine surgery. Patients frequently inquire when they may safely resume driving after cervical spine surgery. There is no consensus regarding post-operative driving restrictions. This study addresses how surgeons differ in their recommendations concerning cervical immobilization, narcotic analgesia, and suggested timeline of return to driving following cervical spine surgery. METHODS:Surgeons at the Cervical Spine Research Society annual meeting completed anonymous surveys assessing postoperative patient management following fusion and non-fusion cervical spine surgeries. RESULTS:70% of surgeons returned completed surveys (n = 71). 80.3% were orthopaedic surgeons and 94.2% completed a spine fellowship. Experienced surgeons (>15y in practice) were more likely to let patients return to driving within 2 weeks than less experienced surgeons (47.1% vs 24.3%, p = .013) for multi-level ACDF and laminectomy with fusion procedures. There were no differences between surgeons practicing inside and outside the USA for prescribing collars or return to driving time. Cervical collars were used more for fusions than non-fusions (57.7% vs 31.0%, p = .001). Surgeons reported 75.3% of patients ask when they may resume driving. For cervical fusions, 31.4% of surgeons allowed their patients to resume driving while restricting them with collars for longer durations. Furthermore, 27.5% of surgeons allowed their patients to resume driving while taking narcotics post-operatively. CONCLUSIONS:This survey-based study highlights the lack of consensus regarding patient 'fitness to drive' following cervical spine surgery. The importance of establishing evidence-based guidelines is critical as recommendations for driving in the post-operative period may have significant medical, legal, and financial implications. LEVEL OF EVIDENCE/METHODS:5.

Background/UNASSIGNED:Anterior cervical discectomy and fusion (ACDF) may be performed using an interbody cage or graft with an anterior plate or with a stand-alone (SA) interbody device without the anterior plate. The pros and cons of each vary. This study examined the radiographic outcome of the two techniques with a focus on implant subsidence. Methods/UNASSIGNED:A retrospective review of cases of singe level ACDF by a single surgeon was undertaken. Medical and radiographic records were reviewed to determine subsidence, pre- and post-operative segmental and total lordosis in cohorts of both stand-alone and graft-and-plate constructs. Results/UNASSIGNED:The post-operative radiographs of 35 patients with a SA cage were compared with 41 patients with an allograft block and anterior plate (graft and plate; GP). There was no significant difference in overall subsidence between the two groups although there was a trend toward less clinically significant subsidence (2 mm) in the SA group. For single level ACDF, a SA device appears to be comparable in terms of undesired subsidence. Conclusions/UNASSIGNED:Further studies with different implants and materials may offer further insight.

Spinal cord compression due to synovial facet cyst in thoracolumbar spine is rare. Several etiologies of juxtafacet cysts (JFCs) in this location have been discussed, particularly overload of the arthritic facet joints. Due to the narrow caliber of the thoracic spine, JFC in this location can present with radicular pain or progressive myelopathy. We report an interesting case of a 67 year-old woman who presented with the signs and symptoms of thoracic myelopathy. A left-sided T11/12 JFC was identified on MRI and CT scans correlating with her myelopathy. She experienced a substantial improvement in her myelopathic symptoms after surgical excision of the JFC. The presentation, etiology, and therapeutic aspects of JFC are discussed in detail.

Degenerative spondylolisthesis is a common presentation, yet the best surgical treatment continues to be a matter of debate. Interbody fusion is one of a number of options, but its exact role remains ill defined. The aim of this study was to provide a contemporary review of the literature to help determine the role, if any, of interbody fusion in the surgical treatment of degenerative spondylolisthesis. A systematic review of the literature since 2005 was performed. Details on study size, patient age, surgical treatments, levels of slip, patient reported outcome measures, radiographic outcomes, complications and selected utility measures were recorded. Studies that compared a cohort treated with interbody fusion and at least one other surgical intervention for comparison were included for review. Only studies examining the effect in degenerative spondylolisthesis were included. Two authors independently reviewed the manuscripts and extracted key data. Thirteen studies were included in the final analysis. A total of 565 underwent interbody fusion and 761 underwent other procedures including decompression alone, interspinous stabilisation and posterolateral fusion with or without instrumentation. Most studies were graded Level III evidence. Heterogeneous reporting of outcomes prevented formal statistical analysis. However, in general, studies reviewed concluded no significant clinical or radiographic difference in outcome between interbody fusion and other treatments. Two small studies suggested interbody fusion is a better option in cases of definite instability. Interbody fusion only provided outcomes as good as instrumented posterolateral fusion. However, most studies were Level III, and hence, we remain limited in defining the exact role of interbody fusion-cases with clear instability appear to be most appropriate. Future work should use agreed-upon common outcome measures and definitions.