Echographic characterization of extraocular muscles in pediatric patients with thyroid dysfunction.

PURPOSE: To characterize the size of extraocular muscles (EOMs) in a pediatric population with thyroid dysfunction using orbital echography. METHODS: Patients under age 18 with thyroid dysfunction who presented to an academic ophthalmology department from 2009 to 2020 and received orbital echography were included in this IRB-approved retrospective study. Data collected included age, clinical activity score (CAS), thyroid stimulating immunoglobulin (TSI), and extraocular recti muscle thickness on echography. Patients were organized into three age cohorts, after which statistical analysis compared recti measurements to previously reported normal ranges. RESULTS: Twenty patients with thyroid dysfunction were included. When comparing average recti muscle thicknesses of study patients to those of previously published normal children in similar age ranges, the levator-superior rectus complex was significantly increased in all age groups of children with thyroid dysfunction (p-values = <.004), and the levator-superior rectus complex was most frequently enlarged compared to published normal values (78% of eyes). CAS was not correlated with EOM size in the youngest group (5-10 years old, p-values >.315) but was significantly correlated in older groups (11-17 years old, p-values <.027). TSI was not correlated with EOM size in any group (p-values >.206). CONCLUSIONS: Echographic reference ranges for EOMs in children with thyroid dysfunction were established. There are increased rates of levator-superior rectus complex enlargement in children with TED compared to adults with TED, and EOM size is correlated with CAS in children older than 10 years. Though limited, these findings may serve as an additional tool for ophthalmologists to ascertain disease activity in pediatric patients with thyroid dysfunction.

A direct transcutaneous approach to infraorbital nerve biopsy.

PURPOSE: To describe a novel transcutaneous infraorbital nerve biopsy technique which can be performed to aid in the diagnosis of perineural invasion (PNI) of facial cutaneous squamous cell carcinoma (SCC). METHODS: A single-center retrospective chart review was performed. Patients diagnosed with SCC with PNI via an infraorbital nerve biopsy between February 2019 and February 2020 were included. Data collected consisted of patient demographics, medical history, clinical presentation and exam, histologic and radiographic findings, treatment, and outcomes. RESULTS: Four patients (3 male, 1 female) met inclusion criteria. The mean age at diagnosis was 79.5 years (range 66-85 years). Three of the four patients had a history of facial skin lesions, including actinic keratosis and SCC, involving the nose, cheek, or ear. One patient had no history of cutaneous malignancy. All patients presented with cranial neuropathies, including total V2 hypoesthesia. The most common presenting symptom was facial pain, followed by diplopia, unilateral facial weakness, and hypoesthesia in the V1 and/or V2 distribution. Transcutaneous infraorbital nerve biopsy in all patients revealed squamous cell carcinoma with no biopsy complications. CONCLUSION: Definitive diagnosis of PNI can be challenging but is important to minimize tumor-related morbidity. Infraorbital nerve biopsy can establish this diagnosis, especially in the context of negative or indeterminate imaging findings. This work comprises the first description of a transcutaneous approach to infraorbital nerve biopsy, which is a minimally invasive technique that can be performed in an outpatient procedure suite with limited to no sedation.

Flipped ophthalmology classroom augmented with case-based learning.

BACKGROUND: Although the flipped classroom model provides an effective way to teach ophthalmology to medical students, there are concerns that it overburdens the learner. The purpose of this study was to assess medical students' perceptions of a case-based flipped classroom style compared with a traditional didactic lecture series and to evaluate the effects of case-based learning on students' confidence in managing common ophthalmic complaints. METHODS: We created an interactive, case-based flipped classroom ophthalmology curriculum. Paired pre- and post-clerkship surveys were distributed to students on the first and last day of the 2-week clerkship. Questions were formatted as statements using a 6-point Likert scale to assess students' prior exposure to a flipped classroom, perceptions of the flipped classroom curriculum, and confidence in evaluating ophthalmic complaints. RESULTS: A total of 75 students were included during the period July 2019 to March 2020. Pre-clerkship questionnaires revealed no preference for either teaching modality. Wilcoxon signed-rank testing comparing pre- and post-clerkship data revealed a significant increase in students' favoring the case-based flipped-classroom model. Participants reported significant reductions in pressure to perform, course burden, and overall anxiety as well as increased confidence in triaging common eye complaints. CONCLUSIONS: The case-based flipped classroom modality prioritizes key learning objectives while increasing student participation and confidence. The reproducibility and accessibility of standardized prepared video lectures and cases may help institutions to better incorporate ophthalmology into preexisting rotations.

A Comparison of the Flipped Classroom Model for Medical Student Education in Ophthalmology before and during the COVID-19 Pandemic.

Background The coronavirus disease 2019 (COVID-19) pandemic has necessitated a shift of medical education to online learning in lieu of traditional clinic-based rotations. The flipped classroom model, which has been shown to be an effective approach to the medical student ophthalmology curriculum, shows promise as a method of learning that can be shared virtually. As such, the aim of this study was to investigate the effectiveness of a flipped classroom approach to the primary care-focused ophthalmology clerkship delivered entirely online in the face of the COVID-19 pandemic. Methods Medical students who completed the 2-week introductory clinical ophthalmology clerkship from July 2019 to July 2020 were included in this study. The curriculum centers on a flipped classroom model and was delivered in person prior to March 2020, after which it transitioned to an online format for 5 months. A survey was administered to students completing this rotation, which utilized 6-point Likert scales to assess students' interest in the field of ophthalmology, perceptions of the flipped classroom curriculum, and confidence in evaluating ophthalmic complaints. The cohort that completed in-person learning was then compared with the cohort that completed online learning. Results A total of 112 responding students were included in our analysis, with 68/82 students from the in-person cohort and 44/66 students in the online cohort responding to the survey. Students who participated in the online virtual clerkship were equally likely to feel comfortable evaluating eye complaints than those who participated in the in-person clerkship, and more likely to report that the course enhanced their interest in ophthalmology. However, online students were less likely to feel comfortable using the direct ophthalmoscope compared with those in the in-person cohort. Conclusion Regardless of its mode of delivery, the flipped classroom model is able to impart confidence in evaluating ophthalmic complaints and interest in the field of ophthalmology to medical students. While online learning can never serve as a full replacement for learning physical examination skills and other important clinical experiences, there are aspects of the virtual flipped classroom that do not compromise student's learning and engagement and may be implemented into curricula even after clinical activities are allowed to resume.

The Effect of Photographic Visual Aids in Preoperative Patient Counseling in Oculoplastic Surgery.

PURPOSE: To investigate the effect of visual supplementation and its mode of delivery in preoperative counseling of patients undergoing oculoplastic surgery. METHODS: A prospective randomized controlled trial of consecutive patients undergoing oculoplastic eyebrow and eyelid surgery was conducted. Patients were randomized to an "oral only" group receiving routine preoperative oral counseling or an "oral and visual" group receiving identical counseling visually supplemented with photographs demonstrating common postoperative physical findings. Patients in the "oral and visual" group were further randomized to receive education from the medical team in person versus prerecorded video. Patient emotions and expectations regarding postoperative healing were assessed preoperatively and at 1 week and 2 months postoperatively. RESULTS: 103 patients were included: 32 received in-person oral education, 33 received in-person oral education with photographs, and 38 received education with photographs via video. There were no significant differences in demographics or preoperative patient fear, anxiety, or preparedness. The "oral and visual" group expected more severe postsurgical discomfort and physical findings at postoperative day 1 and week 1. There were no significant differences between groups in surgery signup, cancellation, or triage call rates; patient expectations of postoperative months 2 and 4; or in anxiety, preparedness, or satisfaction. CONCLUSIONS: Visual supplementation in preoperative counseling increases patient expectations of postoperative physical findings without escalating fear or anxiety, and has no significant impact on patient emotions, triage call rates, and satisfaction throughout their surgical experience. Preoperative education via video is perceived by patients to be equivalent to counseling in person by the surgeon.

Risk Factors for Medical and Surgical Complications after 1-2-Level Anterior Cervical Discectomy and Fusion Procedures.

BACKGROUND: Postoperative complications after anterior cervical discectomy and fusion (ACDF) have a significant impact on clinical outcomes and health care resource use. Identifying predictive factors for complications after ACDF may allow for the modification of care protocols to mitigate complication risk. The purpose of this study is to determine risk factors for the incidence of medical and surgical complications up to 2 years postoperatively after ACDF procedures. METHODS: A prospectively maintained surgical registry of patients who underwent primary, 1-2-level ACDF was retrospectively reviewed. The incidence of medical and surgical complications up to 2 years postoperatively was determined. Patients were classified according to demographic, comorbidity, and procedural characteristics. Bivariate Poisson regression with robust error variance was used to determine if an association existed between the incidence of medical or surgical complications and patient characteristics. A final multivariate model including all patient and procedural characteristics as controls was created using backwards, stepwise regression until only those variables with P < .05 remained. RESULTS: A total of 310 patients were included. Upon bivariate analysis, age >50 years was identified as a risk factor for medical complications after ACDF procedures. Additionally, bivariate analysis identified ageless Charlson comorbidity index ≥2, operative duration >60 minutes, and 2-level procedures as risk factors for surgical complications after ACDF. Upon multivariate analysis, age >50 years was identified as an independent risk factor for medical complications (relative risk [RR] = 3.6, P = .005), while operative time >60 minutes was identified as an independent risk factor for surgical complications after ACDF (RR = 4.5, P = .017). CONCLUSIONS: The results of this study demonstrate that older age and longer operative time were independent risk factors for medical and surgical complications, respectively, following ACDF. Patients with these risk factors should be counseled regarding their increased risk of postoperative complications and should undergo more vigilant monitoring to aid in complication avoidance. LEVEL OF EVIDENCE: 3. CLINICAL RELEVANCE: Surgeons should consider the elevated risk of postoperative complications in >50 years old patients and >60 min procedures.

Risk Factors for Medical and Surgical Complications After Single-Level Minimally Invasive Transforaminal Lumbar Interbody Fusion.

BACKGROUND: The prevention of perioperative and postoperative complications is necessary to avoid poor postoperative outcomes and increased costs. Previous investigations have identified risk factors for complications after various spine procedures, but no such study exists in a population solely undergoing minimally invasive transforaminal lumbar interbody fusion (MIS TLIF). The purpose of this study is to determine risk factors for the development of complications up to 2 years after MIS TLIF procedures. METHODS: Patients who underwent primary, single-level MIS TLIF from 2007 to 2016 were retrospectively reviewed. The incidence of medical and surgical complications up to 2 years postoperatively was determined. Patients were categorized according to demographic, comorbidity, and procedural characteristics. Bivariate Poisson regression with robust error variance was used to determine if an association existed between patient characteristics and complication incidence. A final multivariate model including all patient characteristics as controls was created using backwards, stepwise regression until only those variables with P < .05 remained. RESULTS: 390 patients were analyzed. Upon bivariate analysis, age >50 years (P = .025), diabetes mellitus (P = .001), and operative duration >105 minutes (P = .016) were associated with increased medical complication rates. Regarding surgical complications, age ≤50 years (P < .001), obesity (P = .012), and diabetes mellitus (P = .042) were identified as risk factors on bivariate analysis. Upon final multivariate analysis, operative time >105 minutes (P = .009) and diabetes mellitus (P = .001) were independent risk factors for medical complications. Independent risk factors for surgical complications on multivariate analysis included age ≤50 years (P < .001), diabetes mellitus (P = .002), and obesity (P = .030). CONCLUSIONS: Diabetic patients and those who underwent longer operations were at increased risk of medical complications, while younger patients, obese patients and those also with diabetes mellitus were at increased risk of surgical complications up to 2 years after MIS TLIF. Practitioners can use this information to identify patients who require preventative care before their procedure or increased postoperative vigilance and monitoring after single-level MIS TLIF. LEVEL OF EVIDENCE: 3.

American Society of Anesthesiologists Score is Not Predictive of Complication Incidence After Minimally Invasive Posterior Lumbar Spine Procedures.

BACKGROUND: Complications occurring after spinal procedures are associated with recurrent symptomatology, new-onset symptomatology, and increased health care costs. The American Society of Anesthesiologists (ASA) score is a commonly cited risk factor for complication incidence. Few investigations have been performed analyzing the relationship between ASA score and complication rate following spinal minimally invasive surgery (MIS) decompressions or fusions. Therefore, the purpose of this study is to determine whether an association exists between preoperative ASA score and the incidence of postoperative complications among patients undergoing MIS posterior lumbar decompression or fusion. METHODS: A surgical registry of patients undergoing single-level MIS posterior lumbar decompressions or fusions between 2007 and 2016 was retrospectively reviewed. Patients were stratified by preoperative ASA score (≤2, >2). The ASA score was tested for an association with preoperative demographic, comorbidity, and perioperative characteristics using the Student t test or χ2 analysis. Multivariate Poisson regression with robust error variance was used to test for an association between ASA score and the incidence of complications up to 6 months postoperatively. RESULTS: A total of 772 patients were analyzed. Of those, 86.7% had an ASA score ≤2, whereas 13.3% had an ASA score >2. An ASA score >2 was associated with older age (P < .001), higher comorbidity burden (P < .001), and higher rates of obesity (P < .001). An ASA score >2 was also associated with significantly longer operative time (P = .001) and longer length of hospital stay (P < .001). Upon multivariate analysis, ASA score category was not associated with the incidence of any complication (P = .248), medical complications (P = .227), or surgical complications (P = .816). CONCLUSIONS: The ASA score was not a predictive factor for complication incidence up to 6 months postoperatively. Thus, a higher ASA score should not preclude patients from being surgical candidates for MIS posterior lumbar decompressions or fusions. Further investigation is required to identify other predictive factors for complication incidence after minimally invasive spine surgery. LEVEL OF EVIDENCE: 3.

Predictors of Citation Rate in the Spine Literature.

The number of citations a publication receives has been regarded as one measure of its importance and clinical impact. However, studies have yet to investigate which characteristics are predictors of citation rates within the spine subspecialty literature. To explore this topic, all articles published in 2010 in Spine and from 2010 to 2011 in The Spine Journal and the Journal of Neurosurgery: Spine were reviewed. The Web of Science search engine was used to determine the number of times each article was cited in the 5 years following its publication. Sample characteristics were collected and were compared with a χ test for differences Multivariate logistic regression was utilized to determine if collected study characteristics were associated with achievement of citation frequency higher than the median for the entire study sample. Among the 927 articles analyzed, the 5-year citation number ranged from 0 to 125, with a median of 8 (interquartile range: 4-16). Upon multivariate analysis, the following were identified as predictors of citation number higher than the median: North American origin (P=0.014), sample size >30 (P<0.001), study topic (P<0.050), and publication in the Journal of Neurosurgery: Spine (P<0.001). Practitioners and research personnel can use these findings to help elucidate which factors might affect the potential impact and overall reach of their work in the spine literature.

Risk Factors Associated With Failure to Reach Minimal Clinically Important Difference in Patient-Reported Outcomes Following Anterior Cervical Discectomy and Fusion.

BACKGROUND: The minimum clinically importance difference (MCID) represents a threshold for improvements in patient-reported outcomes (PROs) that patients deem important. No previous study has comprehensively examined risk factors for failure to achieve MCID after anterior cervical discectomy and fusion (ACDF) procedures for radiculopathic symptomatology. The purpose of this study is to determine risk factors for failure to reach MCID for Neck Disability Index (NDI), Visual Analog Scale (VAS) neck pain, and VAS arm pain in patients undergoing 1- or 2-level ACDF procedures. METHODS: A surgical registry of patients who underwent primary, 1- or 2-level ACDF from 2014 to 2016 was reviewed. Rates of MCID achievement for NDI, VAS neck pain, and VAS arm pain at final follow-up were calculated based on published MCID values. Patients were then categorized into demographic and procedural categories. Bivariate regression was used to test for association of demographic and procedural characteristics with failure to reach MCID for each PRO. The final multivariate model including all demographic and procedural categories as controls was created using backward stepwise regression. RESULTS: Eighty-three, 84, and 77 patients were included in the analysis for VAS neck, VAS arm, and NDI, respectively. Rates of MCID achievement for VAS neck, VAS arm, and NDI were 55.4%, 36.9%, and 76.6%, respectively. On bivariate analysis, patients with Charlson Comorbidity Index (CCI) ≥ 2 were less likely to achieve MCID for NDI than patients with CCI < 2 (P = .025). On multivariate analysis, CCI ≥ 2 (P = .025) was further associated with failure to reach MCID for NDI. CONCLUSIONS: The results of this study suggest that the majority of patients do not reach MCID for arm pain. Additionally, higher comorbidity burden as evidenced by higher CCI scores is a negative predictive factor for the achievement of MCID in neck disability following ACDF. LEVEL OF EVIDENCE: 3.

Resolution of self-injurious behavior in a nonverbal and developmentally delayed patient after surgical treatment of a blind painful eye.

Changes in behavioral patterns can be the only indication of the presence of pain in nonverbal patients. Phthisis bulbi results in shrinking, disorganization, and sometimes severe inflammation of the ocular globe and can occur after eye injury or multiple eye surgeries. Chronic tearing, frequent eye rubbing, and self-injurious behavior focused around the eye and periocular region may indicate ocular discomfort in nonverbal patients. In eyes that become painful and refractory to medical treatment, ocular evisceration or enucleation can provide immediate pain relief. An ocular prosthesis provides excellent cosmetic results to restore normal facial appearance after surgery.

Does Day of Surgery Affect Hospital Length of Stay and Charges Following Minimally Invasive Transforaminal Lumbar Interbody Fusion?

STUDY DESIGN: Retrospective Cohort. OBJECTIVE: To determine if an association exists between surgery day and length of stay or hospital costs after minimally invasive transforaminal lumbar interbody fusion (MIS TLIF). SUMMARYOF BACKGROUND DATA: Length of inpatient stay after orthopedic procedures has been identified as a primary cost driver, and previous research has focused on determining risk factors for prolonged length of stay. In the arthroplasty literature, surgery performed later in the week has been identified as a predictor of increased length of stay. However, no such investigation has been performed for MIS TLIF. MATERIALS AND METHODS: A surgical registry of patients undergoing MIS TLIF between 2008 and 2016 was retrospectively reviewed. Patients were grouped based on day of surgery, with groups including early surgery and late surgery. Day of surgery group was tested for an association with demographics and perioperative variables using the student t test or χ analysis. Day of surgery group was then tested for an association with direct hospital costs using multivariate linear regression. RESULTS: In total, 438 patients were analyzed. In total, 51.8% were in the early surgery group, and 48.2% were in the late surgery group. There were no differences in demographics between groups. There were no differences between groups with regard to operative time, intraoperative blood loss, length of stay, or discharge day. Finally, there were no differences in total hospital charges between early and late surgery groups (P=0.247). CONCLUSIONS: The specific day on which a MIS TLIF procedure occurs is not associated with differences in length of inpatient stay or total hospital costs. This suggests that the postoperative course after MIS TLIF procedures is not affected by the differences in hospital staffing that occurs on the weekend compared with weekdays.

Authorship Trends in Spine Publications From 2000 to 2015.

STUDY DESIGN: Literature review. OBJECTIVE: To examine changes in authorship characteristics for Spine publications from the year 2000 to 2015. SUMMARY OF BACKGROUND DATA: Scientific publications are considered an indication of academic achievement for physicians. Recently, authorship trends have been investigated; however, limited information is available on this topic within spine-specific literature. METHODS: Original research articles published in Spine in the years 2000, 2005, 2010, and 2015 were evaluated. Authorship characteristics were collected for each article, including the number of authors and institutions per publication, first and last authors' sex, publication origin, and highest degree held by the first and last author. Trends over time were analyzed using numeric and visual descriptive analyses including percentages, means, standard deviations, and graphs. RESULTS: An average of 506 articles per year was published in Spine during the years 2000, 2005, 2010, and 2015. The number of articles written by 10 or more authors increased during this time (0.9%-14.4%). There was a substantial increase in the number of multiple institutional affiliations (33.6%-68.7%) and articles originating from outside North America (47.6%-55.7%) from 2000 to 2015. The percentage of first authors with bachelor's degrees was higher in 2015 (6.6%) as compared to 2000 (1.4%), and more last authors were identified as MD/PhDs in 2015 (19.2%) than in 2000 (10.0%). Similar female representation was noted for first and last authorship for all years evaluated. CONCLUSION: The results of this study demonstrate increases in authors per article published in Spine from 2000 to 2015. In addition, first authors were more likely to hold bachelor's degrees over time. This may be attributed to increasing competition in spine-related fields, necessitating earlier research exposure to aid in academic achievement. Interestingly, the percentage of female authorship has not changed significantly over time, in contrast with much of the previous literature. LEVEL OF EVIDENCE: 2.

Variation in Spine Surgeon Selection Criteria Between Neurosurgery and Orthopedic Surgery Patients.

STUDY DESIGN: A cross-sectional survey study. OBJECTIVE: The objective of this study is to determine if there are any differences in spine surgeon selection criteria between neurosurgery patients and orthopedic patients. BACKGROUND INFORMATION: The evolution of the health care delivery system has allowed for increased patient autonomy in provider selection. However, the process and criteria by which patients choose particular spine surgeons is not well understood. Furthermore, differences in physician selection criteria used by patients who present either to a neurosurgery or orthopedic spine surgeon has not been previously established. MATERIALS AND METHODS: An anonymous questionnaire consisting of 26 questions was administered to 644 patients seeking treatment from either a single neurosurgery-trained or orthopedics-trained spine surgeon at an urban institution. Four questions pertained to demographic variables. Sixteen questions asked patients to rate specific spine surgeon selection criteria in terms of importance (scale, 1-10). Six questions were multiple choice, asking patients to select their preferences towards aspects of a spine surgeon. Patient responses were compared using χ analysis or Fisher exact test for categorical variables. RESULTS: The 3 most important factors for selecting a spine surgeon were the same for neurosurgery and orthopedic surgery patients: board certification (neurosurgery, orthopedic surgery) (9.07±2.35, 9.22±1.79), in-network provider status (8.01±3.15, 8.09±3.03), and surgeon bedside manner (7.88±2.52, 8.07±2.29). When listing their preference regarding surgeon specialty training, 82.74% of neurosurgery patients and 48.81% of orthopedic surgery patients preferred a surgeon who was trained in neurosurgery. CONCLUSIONS: The growth in patient autonomy within the current health care system has emphasized the importance of identifying patient preferences in the physician selection process.Board certification, in-network insurance status, and bedside manner may be the most influential factors for patients in spine surgeon selection irrespective of surgical subspecialty. Patients may also be more likely to seek spine surgeons with neurosurgery training over orthopedic surgery training. The present study provides spine surgeons a framework to improve both patient recruitment and patient satisfaction.

Impact of body mass index on surgical outcomes, narcotics consumption, and hospital costs following anterior cervical discectomy and fusion.

OBJECTIVE Given the increasing prevalence of obesity, more patients with a high body mass index (BMI) will require surgical treatment for degenerative spinal disease. In previous investigations of lumbar spine pathology, obesity has been associated with worsened postoperative outcomes and increased costs. However, few studies have examined the association between BMI and postoperative outcomes following anterior cervical discectomy and fusion (ACDF) procedures. Thus, the purpose of this study was to compare surgical outcomes, postoperative narcotics consumption, complications, and hospital costs among BMI stratifications for patients who have undergone primary 1- to 2-level ACDF procedures. METHODS The authors retrospectively reviewed a prospectively maintained surgical database of patients who had undergone primary 1- to 2-level ACDF for degenerative spinal pathology between 2008 and 2015. Patients were stratified by BMI as follows: normal weight (< 25.0 kg/m2), overweight (25.0-29.9 kg/m2), obese I (30.0-34.9 kg/m2), or obese II-III (≥ 35.0 kg/m2). Differences in patient demographics and preoperative characteristics were compared across the BMI cohorts using 1-way ANOVA or chi-square analysis. Multivariate linear or Poisson regression with robust error variance was used to determine the presence of an association between BMI category and narcotics utilization, improvement in visual analog scale (VAS) scores, incidence of complications, arthrodesis rates, reoperation rates, and hospital costs. Regression analyses were controlled for preoperative demographic and procedural characteristics. RESULTS Two hundred seventy-seven patients were included in the analysis, of whom 20.9% (n = 58) were normal weight, 37.5% (n = 104) were overweight, 24.9% (n = 69) were obese I, and 16.6% (n = 46) were obese II-III. A higher BMI was associated with an older age (p = 0.049) and increased comorbidity burden (p = 0.001). No differences in sex, smoking status, insurance type, diagnosis, presence of neuropathy, or preoperative VAS pain scores were found among the BMI cohorts (p > 0.05). No significant differences were found among these cohorts as regards operative time, intraoperative blood loss, length of hospital stay, and number of operative levels (p > 0.05). Additionally, no significant differences in postoperative narcotics consumption, VAS score improvement, complication rates, arthrodesis rates, reoperation rates, or total direct costs existed across BMI stratifications (p > 0.05). CONCLUSIONS Patients with a higher BMI demonstrated surgical outcomes, narcotics consumption, and hospital costs comparable to those of patients with a lower BMI. Thus, ACDF procedures are both safe and effective for all patients across the entire BMI spectrum. Patients should be counseled to expect similar rates of postoperative complications and eventual clinical improvement regardless of their BMI.

Is Body Mass Index a Risk Factor for Revision Procedures After Minimally Invasive Transforaminal Lumbar Interbody Fusion?

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To determine if an association exists between body mass index (BMI) and the rate of revision surgery after single-level minimally invasive transforaminal lumbar interbody fusion (MIS TLIF). SUMMARY OF BACKGROUND DATA: MIS TLIF is an effective treatment for lumbar degenerative disease. Previous studies in the orthopedic literature have associated increased BMI with increased postoperative complications and need for revision. Few studies have evaluated the association between BMI and the risk for revision after minimally invasive spinal procedures. MATERIALS AND METHODS: A surgical registry of patients who underwent a single-level MIS TLIF for degenerative pathology between 2005 and 2014 was reviewed. Patients were stratified based on BMI category: normal weight (BMI<25), overweight (BMI, 25-29.9), obese I (BMI, 30-34.9), and obese II-III (BMI≥35). BMI category was tested for association with demographic and procedural characteristics using 1-way analysis of variance (ANOVA) for continuous variables, and χ analysis or the Fisher exact test for categorical variables. BMI category was tested for association with undergoing a revision fusion procedure within 2 years after MIS TLIF using multivariate Cox proportional hazards survival analysis modeling. RESULTS: In total, 274 patients were analyzed; of these, 52 (18.98%) were normal weight, 101 (36.86%) were overweight, 62 (22.63%) were obese I, and 59 (21.53%) were obese II-III. On multivariate Cox proportional hazards survival analysis modeling, BMI category was not associated with undergoing a revision procedure within 2 years after MIS TLIF (P=0.599). On multivariate analysis, younger age (P=0.004) was associated with increased risk of undergoing a revision after MIS TLIF. CONCLUSIONS: The results of this study suggest that increasing BMI is not a risk factor for undergoing a revision procedure after MIS TLIF. As such, patients with high BMI should be counseled regarding having similar rates of needing a revision procedure after MIS TLIF as those with lower BMI. LEVEL OF EVIDENCE: Level IV.

Risk Factors Associated With Failure to Reach Minimal Clinically Important Difference in Patient-reported Outcomes Following Minimally Invasive Transforaminal Lumbar Interbody Fusion for Spondylolisthesis.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: To determine risk factors associated with failure to reach the minimal clinically important difference (MCID) in patient-reported outcomes (PROs) for patients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) for spondylolisthesis. SUMMARY OF BACKGROUND DATA: The MCID of PROs are often utilized to determine the benefit of spinal procedures. However, negative predictive factors for reaching MCID in patients surgically treated for lumbar spondylolisthesis have been difficult to elucidate. MATERIALS AND METHODS: A prospectively maintained surgical database of patients who were diagnosed with lumbar spondylolisthesis and surgically treated with a single level MIS TLIF from 2010 to 2016 was reviewed. Patients with incomplete PRO survey data or <6-month follow-up were excluded from the analysis. MCID for visual analogue scale (VAS) back, VAS leg, and Oswestry Disability Index (ODI) was obtained from established values in the literature. All risk factors were then assessed for association with failure to reach MCID using bivariate and multivariate regression adjusting for preoperative characteristics. RESULTS: A total of 165, 76, and 73 patients treated with MIS TLIF for spondylolisthesis had complete PRO data for VAS back, VAS leg, and ODI, respectively, and were thus included in the analysis for the respective PRO. Overall, 75.76%, 71.05%, and 61.64% of patients treated with a single level MIS TLIF for spondylolisthesis reached MCID for VAS back, VAS leg, and ODI, respectively. On multivariate analysis, patients were less likely to achieve MCID for VAS back following surgical treatment if they received workers' compensation (P<0.001). No other measured factors were noted to independently correlate with MCID achievement. CONCLUSIONS: The results of this study suggest that a majority of patients with spondylolisthesis achieve MCID for commonly measured PROs following MIS TLIF for spondylolisthesis. However, worker's compensation insurance status may serve as a negative predictive factor for reaching MCID.