Patient-Reported Allergies Do Not Affect Long-Term Patient-Reported Outcome Measures After Spine Surgery.

BACKGROUND: A gap in the literature exists regarding the association between number of allergies and patient-reported outcomes measures (PROMs) for patients undergoing spine surgery. METHODS: Consecutive cervical or lumbar spine surgery patients were identified from a prospective registry from April 2017 to July 2020. Patients were grouped into those with 0, 1, 2, or ≥3 allergies. Demographics were compared between the groups. PROMs included Neck Disability Index, Oswestry Disability Index, visual analog scale (VAS) neck pain, VAS arm pain, VAS back pain, VAS leg pain, short form 12 (SF-12) physical component score, SF-12 mental component score, and patient-reported outcomes measurement information system physical function (PROMIS-PF), and outcomes were compared between the groups through multivariable analysis at up to 1-year follow-up. Associations between number of allergies and achieving a minimal clinically important difference (MCID) in the 9 aforementioned PROMs at 1-year follow-up were assessed. RESULTS: This study included 148 cervical and 517 lumbar patients. After controlling for demographic differences, a higher number of allergies was associated with less improvement in VAS neck pain, SF-12 physical component score, and PROMIS-PF at 12 weeks following cervical surgery and less improvement in PROMIS-PF at 2 weeks following lumbar surgery (P < 0.05). However, these associations failed to persist after 6 months and 12 weeks following surgery in cervical and lumbar patients, respectively (P > 0.05). No association was identified between number of allergies and achievement of MCID in any of the 9 studied PROMs at 1-year follow-up. CONCLUSIONS: The higher number of allergies was associated with less improvement in PROMs in the early postoperative period but not at longer-term follow-up. CLINICAL RELEVANCE: These findings provide data that can be utilized while counseling patients and setting postoperative expectations.

Does loss of spondylolisthesis reduction impact clinical and radiographic outcomes after minimally invasive transforaminal lumbar interbody fusion?

BACKGROUND CONTEXT: Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) is a common operative approach to address degenerative lumbar stenosis and spondylolisthesis which has failed nonoperative care. Compared to open TLIF, MI-TLIF relies to a greater extent on indirect decompression resulting in a heightened awareness of spondylolisthesis reduction among MI surgeons. To what extent intraoperative reduction is achieved as well as the rate and clinical impact of loss or reduction and slip recurrence remain unknown. PURPOSE: To determine the rate and clinical impact of slip recurrence after MI-TLIF with expandable cage technology STUDY DESIGN/SETTING: Retrospective Cohort Study PATIENT SAMPLE: Patients undergoing MI-TLIF for degenerative spondylolisthesis using an articulating, expandable cage OUTCOME MEASURES: Patient-reported outcome measures (PROMs), including the Oswestry Disability Index (ODI), visual analog scale (VAS) for back/leg pain, Short Form-12 (SF-12), and PROMIS Physical Function (PF) METHODS: Patients undergoing MI-TLIF for degenerative spondylolisthesis using articulating, expandable cages from 2017 to 2019 were retrospectively studied. Lateral radiographs were reviewed and evaluated for the presence or absence of spondylolisthesis preoperatively, intraoperatively, and at follow-up times including 2 weeks, 6 weeks, 12 weeks, 6 months, and 1 year postoperatively. Spondylolisthesis was measured from the posterior inferior corner of the cephalad vertebra to the posterior superior corner of the caudal vertebra, with any measurement >1 mm classified as spondylolisthesis, and Meyerding grade was noted. Intraoperative reduction was measured, and loss of reduction was defined as >1 mm increase in spondylolisthesis comparing follow-up imaging to intraoperative films. PROMs were recorded at the preoperative and follow-up time points. Fusion was assessed at 1 year postoperatively via CT. RESULTS: A total of 63 patients and 70 levels were included, with mean age 59.8 years (SD,13.8). 19 levels (27.1%) had complete reduction intraoperatively, 40 (57.1%) had partial reduction, and 11 (15.7%) had no reduction. Of the 30 levels with loss of reduction (50.8%), 20 (66.7%) occurred by 2 weeks postoperatively and 28 (93.3%) occurred by 12 weeks postoperatively. At 6 months, there were significant differences between those who had loss of reduction and those who did not in VAS back pain (3.0 vs. 0.9, p = .017) and SF-12 PCS (41.5 vs. 50.0, p = .035), but no differences were found between the groups for any instruments at any other time points. The overall fusion rate was 82.1% (32/39) at 1 year postoperatively. There was no significant difference in fusion rate between the loss of reduction (16/20) and no loss of reduction (20/23) groups. Patients with loss of reduction had no difference in reoperation rate (1/28) compared to those without loss of reduction (2/24). CONCLUSIONS: While a majority of patients demonstrated reduction intraoperatively, 51% had loss of reduction, most commonly in the acute postoperative period. There were few differences in PROMs between patients who had loss of reduction and those who did not, suggesting that radiographic loss of reduction after MI-TLIF in the setting of degenerative spondylolisthesis may not be clinically meaningful.

Technique, Time Demand, Radiation Exposure, and Outcomes of Skin-anchored Intraoperative 3D Navigation in Minimally Invasive Posterior Cervical Laminoforaminotomy.

STUDY DESIGN: This was a retrospective review. OBJECTIVE: The objective of this study was to describe our technique and evaluate the time demand, radiation exposure, and outcomes of minimally invasive posterior cervical laminoforaminotomy (MI-PCLF) using skin-anchored intraoperative navigation (ION). BACKGROUND: Although bone-anchored trackers are most commonly used for ION, a novel technique utilizing noninvasive skin-anchored trackers has recently been described for lumbar surgery and has shown favorable results. There are currently no reports on the use of this technology for cervical surgery. METHODS: Time demand, radiation exposure, and perioperative outcomes of MI-PCLF using skin-anchored ION were evaluated. RESULTS: Twenty-one patients with 36 operative levels were included. Time for ION setup and operative time were a median of 34 and 62 minutes, respectively. Median radiation to the patient was 2.5 mGy from 10 seconds of fluoroscopy time. Radiation exposure to operating room personnel was negligible because they are behind a protective lead shield during ION image acquisition. There were no intraoperative complications or wrong-level surgeries. One patient required a repeat ION spin, and in 2 patients, ION was abandoned and standard fluoroscopy was used. CONCLUSIONS: Skin-anchored ION for MI-PCLF is feasible, safe, and accurate. It results in short operative times, minimal complications, low radiation to the patient, and negligible radiation to operating room personnel.

The Use of Patient-Reported Outcomes Measurement Information System in Spine: A Systematic Review.

BACKGROUND: The Patient-Reported Outcomes Measurement Information System (PROMIS) was developed to provide an easily administered patient-outcome questionnaire that was adaptable to a variety of medical and surgical subspecialties. Numerous authors have examined the effectiveness of PROMIS in various areas of spine surgery. Our goal was to systematically review PROMIS scores compared with legacy patient-reported outcomes measures (PROMs) in spinal surgery and spine pathology. METHODS: A systematic search of the PubMed, EMBASE, and Cochrane databases using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines was performed, yielding 254 unique studies reporting on "PROMIS" in "spine." Each study was independently reviewed. A total of 16 studies were selected for inclusion. RESULTS: The pooled sample size yielded a total of 4268 patients. In the cervical population, PROMIS physical function (PF; |r| = .47-.87, pain intensity (PIn; |r| = .61-.74), pain interference (PIf; |r| = .65-.88), and pain behavior (PB; |r| = .59-.74) correlated with the Neck Disability Index (NDI). PROMIS PF also strongly correlated with the modified Japanese Orthopaedic Association scale (mJOA; |r| = .61-.72). Among patients with lumbar pathology and adult spinal deformities, PROMIS PF (|r| = .53-.85), PIn (|r| = .73-.78), PIf (|r| = .59-.89), and PB (|r| = .58-.82) strongly correlated with the Oswestry Disability Index (ODI). PF (|r| = .51-.78), PIf (|r| = .60-.70), and anxiety (|r| = .73) also strongly correlated with the Scoliosis Research Society (SRS)-22 and SRS-30. When comparing measures of global health, PROMIS PF was strongly correlated with the Short Form (SF)-12 and SF-36 (|r| = .50-.85). On average, all PROMIS domains required less time to complete (49.6-56 seconds) than the ODI (176 seconds), NDI (190.3 seconds), SF-12 (214 seconds), and SF-36 physical function domains (99 seconds). The responsiveness of the PROMIS PF, PIf, and PB was comparable to that of legacy measures ODI, NDI, and SF-12. CONCLUSIONS: The PROMIS PF, PIn, PIf, and PB demonstrated moderate to strong correlations with NDI, mJOA, ODI, SRS, and SF-12 measures in various populations of spine patients. All PROMIS domains had decreased time to completion and similar responsiveness compared with legacy measures. LEVEL OF EVIDENCE: 2. CLINICAL RELEVANCE: These results highlight the potential of PROMIS as a valid and reliable tool to assess patient-reported outcomes in spinal surgery patients and support more widespread use of PROMIS in spine.

Early Failures After Lumbar Discectomy Surgery: An Analysis of 62 690 Patients.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To determine the rate of early failures (readmission or reoperation for new or recurrent pain/neurological symptoms) within 30 days after lumbar discectomy and identify associated risk factors. METHODS: A retrospective cohort study was conducted of patients undergoing lumbar discectomy in the National Surgical Quality Improvement Program database between 2013 and 2017. Rates of readmission for new or recurrent symptoms or reoperation for revision discectomy or fusion within 30 days postoperatively were measured and correlated with risk factors. RESULTS: In total 62 690 patients were identified; overall rate of readmission within 30 days was 3.3%, including 1.2% for pain or neurological symptoms. Populations at increased risk of readmission were those with 3 or more levels of treatment (2.0%, odds ratio [OR] 2.8%, P < .01), age >70 years (1.8%, OR 1.6, P < .01), class 3 obesity (1.5%, OR 1.4, P = .04), and female gender (1.4%, OR 1.2, P = .02). The overall rate of reoperation within 30 days was 2.2%, including 1.2% for revision decompression or lumbar fusion surgery. Populations at increased risk of reoperation were revision discectomies (1.4%, OR 1.7, P < .01) and females (1.1%, OR 1.4, P < 0.01). Extraforaminal discectomies were associated with lower rates of readmission (0.7%, OR 0.6, P = 0.02) and reoperation (0.4%, OR 0.4, P = .01). CONCLUSIONS: Early failures after lumbar discectomy surgery are rare. However, certain subpopulations are associated with increased rates of early failure: obesity, multilevel surgery, females, and revision discectomies.

Use of Higher-strength Opioids has a Dose-Dependent Association With Reoperations After Lumbar Decompression and Interbody Fusion Surgery.

STUDY DESIGN: A retrospective cohort study. OBJECTIVE: The aim of this study was to identify an association between preoperative opioid use and reoperations rates. SUMMARY OF BACKGROUND DATA: Chronic opioid use is a public health crisis in the United States and has been linked to worse outcomes after lumbar spine surgery. However, no studies have identified an association between preoperative opioid use and reoperations rates. METHODS: A retrospective cohort study was conducted using patients from one private insurance database who underwent primary lumbar decompression/discectomy (LDD) or posterior/transforaminal lumbar interbody fusion (PLIF/TLIF). Preoperative use of five specific opioid medications (tramadol, hydromorphone, oxycodone, hydromorphone, and extended-release oxycodone) was categorized as acute (within 3 months), subacute (acute use and use between 3 and 6 months), or chronic (subacute use and use before 6 months). Multivariate regression, controlling for multilevel surgery, age, sex, and Charlson Comorbidity Index, was used to determine the association of each medication on reoperations within 5 years. RESULTS: A total of 11,551 patients undergoing LDD and 3291 patients undergoing PLIF/TLIF without previous lumbar spine surgery were identified. In the LDD group, opioid-naïve patients had a 5-year reoperation rate of 2.8%, compared with 25.0% and 8.0 with chronic preoperative use of hydromorphone and oxycodone, respectively. In multivariate analysis, any preoperative use of oxycodone was associated with increased reoperations (odds ratios [OR] = 1.4, 2.0, and 2.3, for acute, subacute, and chronic use; P < 0.01). Chronic use of hydromorphone was also associated with increased reoperations (OR = 7.5, P < 0.01).In the PLIF/TLIF group, opioid-naïve patients had a 5-year reoperation rate of 11.3%, compared with 66.7% and 16.8% with chronic preoperative use of hydromorphone and oxycodone, respectively. In multivariate analysis, any preoperative use of hydromorphone was associated with increased reoperations (OR = 2.9, 4.0, and 14.0, for acute, subacute, and chronic use; P < 0.05). CONCLUSION: Preoperative use of the higher-potency opioid medications is associated with increased reoperations after LDD and PLIF/TLIF in a dose-dependent manner. Surgeons should use this data for preoperative opioid cessation counseling and individualized risk stratification.Level of Evidence: 3.

Does interbody cage lordosis impact actual segmental lordosis achieved in minimally invasive lumbar spine fusion?

OBJECTIVE: In an effort to prevent loss of segmental lordosis (SL) with minimally invasive interbody fusions, manufacturers have increased the amount of lordosis that is built into interbody cages. However, the relationship between cage lordotic angle and actual SL achieved intraoperatively remains unclear. The purpose of this study was to determine if the lordotic angle manufactured into an interbody cage impacts the change in SL during minimally invasive surgery (MIS) for lumbar interbody fusion (LIF) done for degenerative pathology. METHODS: The authors performed a retrospective review of a single-surgeon database of adult patients who underwent primary LIF between April 2017 and December 2018. Procedures were performed for 1-2-level lumbar degenerative disease using contemporary MIS techniques, including transforaminal LIF (TLIF), lateral LIF (LLIF), and anterior LIF (ALIF). Surgical levels were classified on lateral radiographs based on the cage lordotic angle (6°-8°, 10°-12°, and 15°-20°) and the position of the cage in the disc space (anterior vs posterior). Change in SL was the primary outcome of interest. Subgroup analyses of the cage lordotic angle within each surgical approach were also conducted. RESULTS: A total of 116 surgical levels in 98 patients were included. Surgical approaches included TLIF (56.1%), LLIF (32.7%), and ALIF (11.2%). There were no differences in SL gained by cage lordotic angle (2.7° SL gain with 6°-8° cages, 1.6° with 10°-12° cages, and 3.4° with 15°-20° cages, p = 0.581). Subgroup analysis of LLIF showed increased SL with 15° cages only (p = 0.002). The change in SL was highest after ALIF (average increase 9.8° in SL vs 1.8° in TLIF vs 1.8° in LLIF, p < 0.001). Anterior position of the cage in the disc space was also associated with a significantly greater gain in SL (4.2° vs -0.3°, p = 0.001), and was the only factor independently correlated with SL gain (p = 0.016). CONCLUSIONS: Compared with cage lordotic angle, cage position and approach play larger roles in the generation of SL in 1-2-level MIS for lumbar degenerative disease.

How do high preoperative pain scores impact the clinical course and outcomes for patients undergoing lumbar microdiscectomy?

OBJECTIVE: Preoperative pain assessment is often used to gauge the amount of disability in patients with lumbar disc herniation. How high preoperative pain scores impact the clinical course and outcomes of patients after lumbar microdiscectomy is not always clear. Here, the authors aimed to determine whether patients reporting higher preoperative pain scores have worse outcomes after lumbar microdiscectomy than those reporting lower preoperative scores. METHODS: The authors performed a retrospective review of patients with symptomatic lumbar disc herniations that had failed to improve with nonsurgical methods and who had undergone tubular lumbar microdiscectomy. Health-related quality of life (HRQOL) scores had been collected in the preoperative and postoperative period. The anatomical severity of disease was graded based on lumbar disc health (Pfirrmann classification), facet degeneration, thecal sac cross-sectional area, and disc herniation grade. Data on each patient's narcotic consumption and length of stay were collected. A Student t-test and chi-square test were used to compare patients with high preoperative pain scores (HP cohort) and those with lower preoperative scores (non-HP cohort). RESULTS: One hundred thirty-eight patients were included in this analysis. The 47 patients in the HP cohort had taken more preoperative opioids (12.0 ± 21.2 vs 3.6 ± 11.1 morphine equivalent doses, p = 0.01). However, there was no statistically significant difference in Pfirrmann classification (p > 0.15), facet grade (p > 0.11), thecal sac cross-sectional area (p = 0.45), or disc herniation grade (p = 0.39) between the HP and non-HP cohorts. The latter cohort had statistically significant higher preoperative PROMIS scores (36.5 ± 7.0 vs 29.9 ± 6.4, p < 0.001), SF-12 mental component summary scores (48.7 ± 11.5 vs 38.9 ± 16.1, p < 0.001), and SF-12 physical component summary scores (PCS; 32.4 ± 8.6 vs 27.5 ± 10.0, p = 0.005), but a lower Oswestry Disability Index (56.4 ± 22.1 vs 35.4 ± 15.5, p < 0.001). There were only two time points after microdiscectomy when the HP cohort had worse HRQOL scores: at the 2-week follow-up for SF-12 PCS scores (32.4 ± 8.6 vs 29.3 ± 7.1, p = 0.03) and the 12-week follow-up for PROMIS scores (45.2 ± 9.5 vs 39.5 ± 7.1, p = 0.01). All other postoperative HRQOL measurements were similar between the two cohorts (p > 0.05). CONCLUSIONS: A patient's perceived severity of disease often does not correlate with the actual clinical pathology on imaging. Although patients who report high pain and have a symptomatic lumbar disc herniation may describe their pain as more extreme, they should be counseled that the outcomes of microdiscectomy are positive.

Psychometric Evaluation of Patient-reported Outcomes Measurement Information System Physical Function Computer Adaptive Testing in Minimally Invasive Lumbar Spine Surgery: An Analysis of Responsiveness, Coverage, Discriminant Validity, and Concurrent Validity.

INTRODUCTION: Although the Patient-reported Outcomes Measurement Information System (PROMIS) is increasingly being used, there are few studies assessing the psychometric properties of PROMIS in minimally invasive spine (MIS) surgery. Thus, the purpose of this study was to perform a psychometric evaluation of PROMIS Physical Function Computer Adaptive Testing (PROMIS-PF CAT) in MIS lumbar surgery. METHODS: The patient-reported outcome measures collected preoperatively and postoperatively of patients undergoing MIS lumbar surgery were retrospectively analyzed to assess responsiveness, coverage, discriminant validity, and concurrent validity of PROMIS-PF CAT. RESULTS: Four hundred twenty-one patients were included. The responsiveness of PROMIS Physical Function (PROMIS-PF) was lower than that of the Oswestry Disability Index (ODI) in the decompression subgroup. Although the ODI had a ceiling effect of 16.7% at 1 year, the Short-Form 12 physical health score and PROMIS-PF did not show floor or ceiling effects. PROMIS-PF demonstrated discriminant validity preoperatively and postoperatively and convergent validity with the ODI, as evidenced by a significant strong negative correlation but not with the Short-Form 12 Physical Health Score, as evidenced by the variability in strength of correlation. CONCLUSIONS: Although the PROMIS-PF showed lower responsiveness than the ODI, particularly in the decompression subgroup, it demonstrated discriminant validity preoperatively and postoperatively, convergent validity with ODI, and better coverage than ODI. These findings suggest that the PROMIS-PF CAT demonstrates reasonable psychometric properties and may be a good surrogate for the ODI.

Fusion rate for stand-alone lateral lumbar interbody fusion: a systematic review.

BACKGROUND: Lateral lumbar interbody fusion (LLIF) is used to treat multiple conditions, including spondylolisthesis, degenerative disc disorders, adjacent segment disease, and degenerative scoliosis. Although many advocate for posterior fixation with LLIF, stand-alone LLIF is increasingly being performed. Yet the fusion rate for stand-alone LLIF is unknown. PURPOSE: Determine the fusion rate for stand-alone LLIF. STUDY DESIGN: Systematic review. METHODS: We queried Cochrane, EMBASE, and MEDLINE for literature on stand-alone LLIF fusion rate with a publication cutoff of April 2020. LLIF surgery was considered stand-alone when not paired with supplemental posterior fixation. Cohort fusion rate differences were calculated and tested for significance (p<0.05). All reported means were pooled. RESULTS: A total of 2,735 publications were assessed. Twenty-two studies met inclusion criteria, including 736 patients and 1,103 vertebral levels. Mean age was 61.7 years with BMI 26.5 kg/m2. Mean fusion rate was 85.6% (range, 53.0%-100.0%), which did not differ significantly by number of levels fused (1-level, 2-level, and ≥3-level). Use of rhBMP-2 was reported in 39.3% of subjects, with no difference in fusion rates between studies using rhBMP-2 (87.7%) and those in which rhBMP-2 was not used (83.9%, odds ratio=1.37, p=0.448). Fusion rate did not differ with the addition of a lateral plate, or by underlying diagnosis. All-complication rate was 42.2% and mean reoperation rate was 11.1%, with 2.3% reoperation due to pseudarthrosis. Of the studies comparing stand-alone to circumferential fusion, pooled fusion rate was found to be 80.4% versus 91.0% (p=0.637). CONCLUSIONS: Stand-alone LLIF yields high fusion rates overall. The wide range of reported fusion rates and lower fusion rates in studies involving subsequent surgical reoperation highlights the importance of proper training in this technique and employing a rigorous algorithm when indicating patients for stand-alone LLIF. Future research should focus on examining risk factors and patient-reported outcomes in stand-alone LLIF.

The necessity and risk factors of subsequent fusion after decompression alone for lumbar spinal stenosis with lumbar spondylolisthesis: 5 years follow-up in two different large populations.

BACKGROUND/CONTEXT: Although decompression without fusion is a reasonable surgical treatment option for some patients with lumbar spinal stenosis (LSS) secondary to spondylolisthesis, some of these patients will require secondary surgery for subsequent fusion. Long-term outcome and need for subsequent fusion in patients treated with decompression alone in the setting of lumbar spondylolisthesis remains controversial. PURPOSE: The aim of this study was to examine the rate, timing, and risk factors of subsequent fusion for patients after decompression alone for LSS with spondylolisthesis. STUDY DESIGN/SETTING: A retrospective cohort study. PATIENT SAMPLE: Patients who had LSS with spondylolisthesis and underwent decompression alone at 1 or 2 levels as a primary lumbar surgery with more than 5 year follow-up. OUTCOME MEASURES: The rate, timing, and risk factors for subsequent fusion. METHODS: Subjects were extracted from both public and private insurance resources in a nationwide insurer database. Risk factors for subsequent fusion were evaluated by multivariate cox proportion-hazard regression controlling for age, gender, comorbidities and the presence or absence of claudication. RESULTS: Five thousand eight hundred and seventy-five patients in the public insurance population (PI population) and 1,456 patients in the private insurance population (PrI population) were included in this study. The rates of patients who needed subsequent fusion were 1.9% at 1 year, 3.5% at 2 years, and 6.7% at 5 years in the PI population, whereas they were 4.3% at 1 year, 8.9% at 2 years, 14.6% at 5 years in the PrI population. The time to subsequent fusion was 730 (365-1234) days in the PI population and 588 (300-998) days in the PrI population. Age less than 70 years, presence of neurogenic claudication and rheumatoid arthritis (RA)/collagen vascular diseases (CVD) were independent risk factors for subsequent fusion in both populations. CONCLUSIONS: Decompression surgery alone can demonstrate good outcomes in some patients with LSS with spondylolisthesis. It is important for surgeons to recognize, however, that patient age less than 70 years, symptomatic neurogenic claudication, and presence of RA and/or CVD are significant independent factors associated with greater likelihood of needing secondary fusion surgery.

The Rate of Heterotopic Ossification Following Cervical Disc Arthroplasty: A Systematic Review and Comparison of Data.

STUDY DESIGN: Systematic review. OBJECTIVES: The purpose of the current study is to determine the overall incidence of Heterotopic Ossification (HO) following cervical disc arthroplasty (CDA) as well as per annum rates. SUMMARY OF BACKGROUND DATA: CDA is a well-established surgical modality for treatment of one- and two-level degenerative disc disease that has failed conservative treatment. Despite its proven mid-term clinical success, the potential for accelerated HO following CDA remains an area of clinical concern. METHODS: A MEDLINE literature search was performed using PubMed, the Cochrane Database of Systematic Reviews, and Embase from January 1980 to February 2018. We included studies involving adult patients, who underwent CDA, documentation of HO, with >12 month follow-up. The pooled results were obtained by calculating the effect size based on the logit event rate. Per annum rates were determined based on weighted averages according to average follow-up period. RESULTS: The initial database review resulted in 230 articles, with 19 articles that met inclusion and exclusion criteria. These pooled results included 2151-disc levels and 1732 patients (50% men and 50% women) who underwent CDA and were evaluated for postoperative HO. The mean age was 45 years with a mean follow-up of 60 months. Sixteen studies reported the occurrence of severe HO resulting in 22.8% of disc levels developing severe HO. When stratifying these studies based on funding type, severe HO was reported at a rate of 21.6% by IDE studies and 27.9% by independent studies. CONCLUSION: The findings of the pooled data show the incidence of severe HO following CDA to be 22.8%. However, there is a significant difference in reported rates of mild and severe HO between IDE and independent data. This alludes to possible underreporting of HO and severity of HO in the industry sponsored IDE studies when compared with independent studies. LEVEL OF EVIDENCE: 2.

Patient Reported Outcomes in Patients Who Stop Following Up: Are They Doing Better or Worse Than the Patients That Come Back?

STUDY DESIGN: Follow-up study. OBJECTIVE: To determine whether minimally invasive lumbar spine surgery outcomes are different between those who are lost to follow-up and those who are not. SUMMARY OF BACKGROUND DATA: Lost to follow-up patients are a common source of selection bias for clinical outcomes research. Currently, there are no US based studies that evaluate the differences in outcomes of lost to follow-up patients after spine surgeries. METHODS: A retrospective review of prospectively collected data of 289 patients who underwent minimally invasive lumbar surgery and were at least 1 year postsurgery was performed. Patients were divided into two groups: (1) lost to follow-up (LTF), defined as patients who had missed more than two consecutive follow-up visits and had not attended their 1-year follow-up appointment; and (2) not lost to follow-up. For the not-LTF cohort, patient response outcome measures (PROMs) (oswestry disability index (ODI), visual analog scale (VAS) back/leg, Short Form-12 (SF-12) Physical/Mental, PROMIS) and return to activities data were collected prospectively at each follow-up. For LTF patients, data were collected through emailed surveys or telephone interviews. PROMs and return to activities data of the two groups were compared. Sub-group analysis by type of surgery (decompression or fusion) was also performed. RESULTS: For the entire cohort, independent t test analysis showed LTF patients had greater improvement in PROMIS Physical Function scores than those who were not-LTF (15.08 vs. 10.38, P = 0.026). For fusion surgeries, LTF patients showed a greater improvement in ODI (-30.94 vs. -16.23, P = 0.003) VAS back (-4.92 vs. -2.99, P = 0.044), and PROMIS-PF (16.09 vs. 10.38, P = 0.049). There were no significant differences in complication rates between LTF and not LTF patients. CONCLUSION: Patients undergoing minimally invasive lumbar surgery-in particular lumbar fusions-who are lost to follow-up and responded to subsequent email and phone interviews showed greater improvements in self-reported outcomes than those who continued to follow-up. Thus, our results suggest that a substantial subset of patients who are lost to follow-up do not fare worse than those who do follow-up. However, an opposite response cannot be excluded in those who did not respond to email and phone interviews. LEVEL OF EVIDENCE: 3.

Medical optimization of modifiable risk factors before thoracolumbar three-column osteotomies: an analysis of 195 patients.

PURPOSE: To determine the rate of preoperative modifiable laboratory abnormalities (both major and minor) and the association with early postoperative medical and surgical complications. METHODS: All patients undergoing thoracolumbar three-column osteotomy between 2013 and 2016 with preoperative laboratory data were identified. Potential preoperative modifiable laboratory abnormalities (major and minor) were assessed including hyponatremia (sodium < 130 and < 135 mEq/L), anemia (hematocrit < 25% and < 30%), renal insufficiency (creatinine ≥ 1.8 and ≥ 1.2 mg/dL), coagulopathy (INR ≥ 1.8 and ≥ 1.2), and hypoalbuminemia (albumin < 2.5 and < 3.5 g/dL). Multivariate logistic regression was used to determine associations with 30-day complications after controlling for possible confounding factors. RESULTS: A total of 195 patients were identified. The rates of major and minor preoperative laboratory abnormalities were 7.7% and 31.3%, respectively. The rates of serious medical, minor medical, and surgical complications over 30-days were 6.7%, 21.5%, and 10.3%, respectively. In multivariate analysis the presence of major preoperative laboratory abnormalities had a significant association with serious medical complications (odds ratio [OR] 77.8, P < 0.001), and minor medical complications (OR 13.3, P < 0.001), but not surgical complications (P = 0.243). The presence of minor preoperative laboratory abnormalities had a significant association with serious medical complications (OR 10.4, P = 0.041) and minor medical complications (OR 2.4, P = 0.045), but not surgical complications (P = 0.490). CONCLUSIONS: While major laboratory abnormalities had a strong association with complications, even minor modifiable laboratory abnormalities had a significant association with both serious and minor medical complications.

A Review of Techniques, Time Demand, Radiation Exposure, and Outcomes of Skin-anchored Intraoperative 3D Navigation in Minimally Invasive Lumbar Spinal Surgery.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: To describe our technique for and evaluate the time demand, radiation exposure and outcomes of skin-anchored intraoperative three-dimensional navigation (ION) in minimally invasive (MIS) lumbar surgery, and to compare these parameters to 2D fluoroscopy for MI-TLIF. SUMMARY OF BACKGROUND DATA: Limited visualization of anatomic landmarks and narrow access corridor in MIS procedures result in greater reliance on image guidance. Although two-dimensional fluoroscopy has historically been used, ION is gaining traction. METHODS: Patients who underwent MIS lumbar microdiscectomy, laminectomy, or MI-TLIF using skin-anchored ION and MI-TLIF by the same surgeon using 2D fluoroscopy were selected. Operative variables, radiation exposure, and short-term outcomes of all procedures were summarized. Time-demand and radiation exposure of fluoroscopy and ION for MI-TLIF were compared. RESULTS: Of the 326 patients included, 232 were in the ION cohort (92 microdiscectomies, 65 laminectomies, and 75 MI-TLIFs) and 94 in the MI-TLIF using 2D fluoroscopy cohort. Time for ION setup and image acquisition was a median of 22 to 24 minutes. Total fluoroscopy time was a median of 10 seconds for microdiscectomy, 9 for laminectomy, and 26 for MI-TLIF. Radiation dose was a median of 15.2 mGy for microdiscectomy, 16.6 for laminectomy, and 44.6 for MI-TLIF, of this, 93%, 95%, and 37% for microdiscectomy, laminectomy, and MI-TLIF, respectively were for ION image acquisition, with the rest attributable to the procedure. There were no wrong-level surgeries. Compared with fluoroscopy, ION for MI-TLIF resulted in lower operative times (92 vs. 108 min, P < 0.0001), fluoroscopy time (26 vs. 144 s, P < 0.0001), and radiation dose (44.6 vs. 63.1 mGy, P = 0.002), with equivalent time-demand and length of stay. ION lowered the radiation dose by 29% for patients and 55% for operating room personnel. CONCLUSION: Skin-anchored ION does not increase time-demand compared with fluoroscopy, is feasible, safe and accurate, and results in low radiation exposure. LEVEL OF EVIDENCE: 3.

Physician Decision-making in Return to Play After Cervical Spine Injury: A Descriptive Analysis of Survey Data.

OF BACKGROUND DATA: Cervical spine injuries commonly occur during athletic play, and such injuries carry significant risk for adverse sequelae if not properly managed. Although guidelines for managing return to play exist, adherence among spine surgeons has not been thoroughly examined. STUDY DESIGN: Prospective analysis of survey data collected from surgeon members of the Cervical Spine Research Society (CSRS) and the International Society for the Advancement of Spine Surgery (ISASS). OBJECTIVE: The objective of this study was to characterize consensus among spine surgeons regarding decision-making on return to competitive sports and level of impact following significant cervical spine injuries from real-life scenarios. MATERIALS AND METHODS: Return to play decisions for 15 clinical cervical spine injury scenarios were compared with current guidelines. Surgeon demographic information such as orthopedic board certification status and years in practice were also analyzed. Weighted kappa analysis was utilized to determine interrater reliability in survey responses. RESULTS: Survey respondents had a poor agreement with both Watkins and Torg guidelines (average weighted κ of 0.027 and 0.066, respectively). Additional kappa analysis of surgeon agreement regarding the "Types of Play" and "Level of Play" for return was still remained poor (Kendall W of 0.312 and 0.200, respectively). Responses were also significantly influenced by surgeon demographics. CONCLUSIONS: There is poor consensus among spine surgeons for return to play following cervical spine injury. These results support the concept that given the gravity of cervical spine injuries, a more standardized approach to decision-making regarding return to play after cervical spine injury is necessary.

Is the likelihood of dysphagia different in patients undergoing one-level versus two-level anterior cervical discectomy and fusion?

BACKGROUND CONTEXT: Dysphagia following anterior cervical discectomy and fusion (ACDF) is a common complication, the etiology of which has not been established. Given that one potential mechanism for dysphagia is local tissue edema, it is thought that a greater number of operative levels may result in higher dysphagia rates. However, prior reports comparing one-level to two-level ACDF have shown varying results. PURPOSE: To determine if there is a difference in dysphagia between one-level and two-level ACDF. STUDY DESIGN/SETTING: Retrospective review of prospectively collected data. PATIENT SAMPLE: Patients who underwent one- or two-level ACDF with a plate-graft construct by a single-surgeon at a high-volume academic medical center. OUTCOME MEASURES: Neck Disability Index, Visual Analog Scale for neck pain and arm pain, Short Form-12 physical and mental health components, and Swallowing Quality of Life (SWAL-QOL) Questionnaire. METHODS: Patient demographics, operative data, and patient-reported outcome measures (PROMs; Neck Disability Index, Visual Analog Scale, Short Form-12, and SWAL-QOL) of patients undergoing one- and two-level ACDF were compared using Fisher exact test for categorical variables and Student's t test for continuous variables. Regression analyses were conducted to identify factors associated with 6- and 12-week SWAL-QOL scores in order to determine whether the number of surgical levels impacts these outcomes. RESULTS: Fifty-eight patients (22 one-level and 36 two-level ACDF) were included. Patients undergoing two-level fusions were older (54.17+8.67 vs 48.06+10.68 years, p=.02) and had longer operative times (69.08+10.51 vs 53.5+14.35 minutes, p<.0001). There were no other significant differences in demographics or operative data. Both groups showed a statistically significant improvement in PROMs from preoperatively to 12 weeks. There was no difference in PROMs or dysphagia rates between groups at any time-point. Younger age (p=.023), male sex (p=.021), longer operative times (p=.068), and worse preoperative SWAL-QOL (p<.0001) were associated with dysphagia at 6 weeks. Preoperative SWAL-QOL was the only variable associated with dysphagia at 12 weeks (p=.003). Operative time of >61.5 minutes had a sensitivity and specificity of 62.1% for worse dysphagia scores at 6 weeks compared with baseline. CONCLUSIONS: The results of our study indicate that there is no difference in the degree of postoperative dysphagia in one- versus two-level ACDF. However, other variables associated with increased postoperative dysphagia in our population included younger age, male sex, procedural time >61.5 minutes, and worse preoperative dysphagia. Larger studies are required to confirm these findings and identify additional risk factors for postoperative dysphagia.

Retrospective Review of Immediate Restoration of Lordosis in Single-Level Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Comparison of Static and Expandable Interbody Cages.

BACKGROUND: Sagittal alignment is an important consideration in spine surgery. The literature is conflicted regarding the effect of minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) on sagittal parameters and the role of expandable cage technology. OBJECTIVE: To compare lordosis generated by static and expandable cages and to determine what factors affect postoperative sagittal parameters. METHODS: Preoperative regional lordosis (RL), segmental lordosis (SL), and posterior disc height (PDH) were compared to postoperative values in single-level MI-TLIF performed using expandable or static cages. Patients were stratified based on preoperative SL: low lordosis (<15 degrees), moderate lordosis (15-25 degrees), and high lordosis (>25 degrees). Regression analyses were conducted to determine factors associated with postoperative SL and PDH. RESULTS: Of the 171 patients included, 111 were in the static and 60 in the expandable cohorts. Patients with low preoperative lordosis experienced an increase in SL and maintained RL regardless of cage type. Those with moderate to high preoperative lordosis experienced a decrease in SL and RL with the static cage, but maintained SL and RL with the expandable cage. Although both cohorts showed an increase in PDH, the increase in the expandable cohort was greater. Preoperative SL was predictive of postoperative SL; preoperative SL, preoperative PDH, and cage type were predictive of postoperative PDH. CONCLUSION: Expandable cages showed favorable results in restoring disc height and maintaining lordosis in the immediate postoperative period. Preoperative SL was the most significant predictor of postoperative SL. Thus, preoperative radiographic parameters and goals of surgery should be important considerations in surgical planning.