Ankur S. Narain

Radiation exposure and reduction in the operating room: Perspectives and future directions in spine surgery

Intraoperative imaging is vital for accurate placement of instrumentation in spine surgery. However, the use of biplanar fluoroscopy and other intraoperative imaging modalities is associated with the risk of significant radiation exposure in the patient, surgeon, and surgical staff. Radiation exposure in the form of ionizing radiation can lead to cellular damage via the induction of DNA lesions and the production of reactive oxygen species. These effects often result in cell death or genomic instability, leading to various radiation-associated pathologies including an increased risk of malignancy. In attempts to reduce radiation-associated health risks, radiation safety has become an important topic in the medical field. All practitioners, regardless of practice setting, can practice radiation safety techniques including shielding and distance to reduce radiation exposure. Additionally, optimization of fluoroscopic settings and techniques can be used as an effective method of radiation dose reduction. New imaging modalities and spinal navigation systems have also been developed in an effort to replace conventional fluoroscopy and reduce radiation doses. These modalities include Isocentric Three-Dimensional C-Arms, O-Arms, and intraoperative magnetic resonance imaging. While this influx of new technology has advanced radiation safety within the field of spine surgery, more work is still required to overcome specific limitations involving increased costs and inadequate training.

Multimodal Analgesia versus Intravenous Patient-controlled Analgesia For Minimally Invasive Transforaminal Lumbar Interbody Fusion Procedures.

Study Design. Retrospective analysis. Objective. To compare postoperative narcotic consumption and pain scores between multimodal analgesia (MMA) and patient-controlled analgesia (PCA) following minimally invasive transforaminal lumbar interbody fusion (MIS TLIF). Summary of Background Data. A multimodal analgesic approach to pain management may lead to decreased pain and narcotic consumption after orthopedic procedures. Additional evidence is, however, required to determine how MMA compares to intravenous PCA after MIS TLIF. Methods. Patients undergoing 1-level MIS TLIF followed by either MMA or PCA at our institution were compared in terms of inpatient pain scores, narcotic consumption, hospital length of stay, rates of surgical complications, rates of inpatient nausea/vomiting, rates of postoperative urinary retention, and rates of narcotic consumption during the months after discharge. Results. A total of 139 patients met inclusion criteria. Of these, 39 (28.1%) received MMA and 100 (71.9%) received PCA. Demographic and comorbidity characteristics did not differ between cohorts. Compared with patients receiving PCA, patients receiving MMA had a lower rate of inpatient narcotic consumption (2.8 ± 1.9 vs. 5.3 ± 4.4 oral morphine equivalents/hour, P < 0.001), a lower rate of inpatient nausea/vomiting (20.5% vs. 48.0%; P = 0.003), and a shorter hospital length of stay (53.0 ± 25.3 vs. 62.6 ± 24.4 h, P = 0.041). There were no differences in Numeric Rating Scale pain score between cohorts for day 0, postoperative day 1, or postoperative day 2 (P > 0.05 for each). There was no difference in the rate of postoperative urinary retention (P > 0.05). Similarly, there were no differences in narcotic consumption at 6 or 12 weeks postoperatively (P > 0.05 for each). Conclusion. These findings suggest that MMA results in reduced inpatient hospital narcotic consumption compared with PCA after MIS TLIF. The decrease in narcotic consumption may contribute to the observed decrease in the rate of inpatient nausea/vomiting and shorter hospital length of stay. Importantly, MMA and PCA resulted in similar analgesia for patients during the inpatient stay. Level of Evidence: 4

Cervical disc arthroplasty: do conflicts of interest influence the outcome of clinical studies?

BACKGROUND CONTEXT Cervical disc arthroplasty (CDA) is an emerging technique for the treatment of cervical degenerative disease. Multiple studies have investigated the outcomes of CDA, particularly in comparison with cervical arthrodesis techniques such as anterior cervical discectomy and fusion (ACDF). As many entities have financial interests in CDA implants, it is imperative to consider the influence of conflicts of interest on the results of studies investigating the efficacy of CDA. PURPOSE This study aimed to determine if there is an association between the presence of conflicts of interest among study authors and the reported outcome of studies involving CDA. STUDY DESIGN This is a systematic review of clinical CDA publications until October 2016. OUTCOME MEASURE The outcome measures are presence of conflicts of interest, level of evidence, and outcome for all included studies. METHODS PubMed and MEDLINE databases were searched for articles presenting clinical, radiographic, and cost outcomes of CDA. Data extracted from each article included title, authors, publication year, level of evidence, prosthesis type, number of operative levels, presence of conflicts of interest, and outcome. Conflicts of interest were determined by the presence of any conflicts for any author within manuscript disclosure sections or through Open Payments reporting. Outcomes of each study were graded as either favorable, unfavorable, or equivocal. The presence of conflicts of interest was tested for an association with the level of evidence and study outcome using Pearson chi-square analysis, Fisher exact test, or logistic regression for categorical variables. The authors report no conflicts of interest directly related to this work, and have not received any funds in support of this work. RESULTS A total of 98 articles were included in this analysis. In total, 44.9% (44) of articles had the presence of a conflict of interest, whereas 55.1% (54) of articles did not. Conflicted studies were more likely to present level I evidence and less likely to present level IV evidence than non-conflicted studies (p<.001). Furthermore, conflicted studies were more likely to report favorable outcomes after CDA than non-conflicted studies (90.9% vs. 74.1%, p=.040). CONCLUSIONS The results of this study suggest that the majority of conflicted and non-conflicted studies report favorable results in patients undergoing CDA. However, conflicted studies were also more likely to report favorable outcomes compared with non-conflicted studies. Individual clinicians must critically review published studies for potential conflicts of interest before incorporating CDA into their practice.

Preoperative mental health status may not be predictive of improvements in patient-reported outcomes following an anterior cervical discectomy and fusion

OBJECTIVE Prior studies have correlated preoperative depression and poor mental health status with inferior patient-reported outcomes following lumbar spinal procedures. However, literature regarding the effect of mental health on outcomes following cervical spinal surgery is limited. As such, the purpose of this study is to test for the association of preoperative SF-12 Mental Component Summary (MCS) scores with improvements in Neck Disability Index (NDI), SF-12 Physical Component Summary (PCS), and neck and arm pain following anterior cervical discectomy and fusion (ACDF). METHODS A prospectively maintained surgical database of patients who underwent a primary 1- or 2-level ACDF during 2014-2015 was reviewed. Patients were excluded if they did not have complete patient-reported outcome data for the preoperative or 6-week, 12-week, or 6-month postoperative visits. At baseline, preoperative SF-12 MCS score was assessed for association with preoperative NDI, neck visual analog scale (VAS) score, arm VAS score, and SF-12 PCS score. The preoperative MCS score was then tested for association with changes in NDI, neck VAS, arm VAS, and SF-12 PCS scores from the preoperative visit to postoperative visits. These tests were conducted using multivariate regression controlling for baseline characteristics as well as for the preoperative score for the patient-reported outcome being assessed. RESULTS A total of 52 patients were included in the analysis. At baseline, a higher preoperative MCS score was negatively associated with a lower preoperative NDI (coefficient: -0.74, p < 0.001) and preoperative arm VAS score (-0.06, p = 0.026), but not preoperative neck VAS score (-0.03, p = 0.325) or SF-12 PCS score (0.04, p = 0.664). Additionally, there was no association between preoperative MCS score and improvement in NDI, neck VAS, arm VAS, or SF-12 PCS score at any of the postoperative time points (6 weeks, 12 weeks, and 6 months, p > 0.05 for each). The percentage of patients achieving a minimum clinically important difference at 6 months did not differ between the bottom and top MCS score halves (p > 0.05 for each). CONCLUSIONS The results of this study suggest that better preoperative mental health status is associated with lower perceived preoperative disability but is not associated with severity of preoperative neck or arm pain. In contrast to other studies, the present study was unable to demonstrate that preoperative mental health is predictive of improvement in patient-reported outcomes at any postoperative time point following an ACDF.

Stand-alone lateral lumbar interbody fusion for the treatment of symptomatic adjacent segment degeneration following previous lumbar fusion

BACKGROUND CONTEXT Revision posterior decompression and fusion surgery for patients with symptomatic adjacent segment degeneration (ASD) is associated with significant morbidity and is technically challenging. The use of a stand-alone lateral lumbar interbody fusion (LLIF) in patients with symptomatic ASD may prevent many of the complications associated with revision posterior surgery. PURPOSE The objective of this study was to assess the clinical and radiographic outcomes of patients who underwent stand-alone LLIF for symptomatic ASD. STUDY DESIGN This is a retrospective case series. PATIENT SAMPLE We retrospectively reviewed patients with a prior posterior instrumented fusion who underwent a subsequent stand-alone LLIF for ASD by a single surgeon. All patients had at least 18 months of follow-up. Patients were diagnosed with symptomatic ASD if they had a previous lumbar fusion with the subsequent development of back pain, neurogenic claudication, or lower extremity radiculopathy in the setting of imaging, which demonstrated stenosis, spondylolisthesis, kyphosis, or scoliosis at the adjacent level. OUTCOME MEASURES Patient-reported outcomes were obtained at preoperative and final follow-up visits using the Oswestry Disability Index [ODI], visual analog scale (VAS)-back, and VAS-leg. Radiographic parameters were measured, including segmental and overall lordoses, pelvic incidence-lumbar lordosis mismatch, coronal alignment, and intervertebral disc height. METHODS Clinical and radiographic outcomes were compared between preoperative and final follow-up using paired t tests. RESULTS Twenty-five patients met inclusion criteria. The mean age was 62.0±11.3 years. The average follow-up was 34.8±22.4 months. Fifteen (60%) underwent stand-alone LLIF surgery for radicular leg pain, 7 (28%) for symptoms of claudication, and 25 (100.0%) for severe back pain. Oswestry Disability Index scores significantly improved from preoperative values (46.6±16.4) to final follow-up (30.4±16.8, p=.002). Visual analog scale-back (preop 8.4±1.0, postop 3.2±1.9; p<.001), and VAS-leg (preop 3.6±3.4, postop 1.9±2.6; p<.001) scores significantly improved following surgery. Segmental and regional lordoses, as well as intervertebral disc height, significantly improved (p<.001) and remained stable (p=.004) by the surgery. Pelvic incidence-lumbar lordosis mismatch significantly improved at the first postoperative visit (p=.029) and was largely maintained at the most recent follow-up (p=.45). Six patients suffered from new-onset thigh weakness following LLIF surgery, but all showed complete resolution within 6 weeks. Three patients required subsequent additional surgeries, all of which were revised to include posterior instrumentation. CONCLUSIONS Stand-alone LLIF is a safe and effective approach with low morbidity and acceptable complication rates for patients with symptomatic ASD following a previous lumbar fusion.

Lateral lumbar interbody fusion: a systematic review of complication rates

BACKGROUND CONTEXT Lateral lumbar interbody fusion (LLIF) is a frequently used technique for the treatment of lumbar pathology. Despite its overall success, LLIF has been associated with a unique set of complications. However, there has been inconsistent evidence regarding the complication rate of this approach. PURPOSE To perform a systematic review analyzing the rates of medical and surgical complications associated with LLIF. STUDY DESIGN Systematic review. PATIENT SAMPLE 6,819 patients who underwent LLIF reported in clinical studies through June 2016. OUTCOME MEASURES Frequency of complications within cardiac, vascular, pulmonary, urologic, gastrointestinal, transient neurologic, persistent neurologic, and spine (MSK) categories. METHODS This systematic review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Relevant studies that identified rates of any complication following LLIF procedures were obtained from PubMed, MEDLINE, and EMBASE databases. Articles were excluded if they did not report complications, presented mixed complication data from other procedures, or were characterized as single case reports, reviews, or case series containing less than 10 patients. The primary outcome was frequency of complications within cardiac, vascular, pulmonary, urologic, gastrointestinal, transient neurologic, persistent neurologic, and MSK categories. All rates of complications were based on the sample sizes of studies that mentioned the respective complications. The authors report no conflicts of interest directly or indirectly related to this work, and have not received any funds in support of this work. RESULTS A total of 2,232 articles were identified. Following screening of title, abstract, and full-text availability, 63 articles were included in the review. A total of 6,819 patients had 11,325 levels fused. The rate of complications for the categories included were as follows: wound (1.38%; 95% confidence interval [CI]=1.00%-1.85%), cardiac (1.86%; CI=1.33%-2.52%), vascular (0.81%; CI=0.44%-1.36%), pulmonary (1.47; CI=0.95%-2.16%), gastrointestinal (1.38%; CI=1.00%-1.87%), urologic (0.93%; CI=0.55%-1.47%), transient neurologic (36.07%; CI=34.74%-37.41%), persistent neurologic (3.98%; CI=3.42%-4.60%), and MSK or spine (9.22%; CI=8.28%-10.23%). CONCLUSIONS The current study is the first to comprehensively analyze the complication profile for LLIFs. The most significant reported complications were transient neurologic in nature. However, persistent neurologic complications occurred at a much lower rate, bringing into question the significance of transient symptoms beyond the immediate postoperative period. Through this analysis of complication profiles, surgeons can better understand the risks to and expectations for patients following LLIF procedures.

Spinal Surgeon Variation in Single-Level Cervical Fusion Procedures: A Cost and Hospital Resource Utilization Analysis.

Study Design. Retrospective analysis. Objective. To compare perioperative costs and outcomes of patients undergoing single-level anterior cervical discectomy and fusions (ACDF) at both a service (orthopedic vs. neurosurgical) and individual surgeon level. Summary of Background Data. Hospital systems are experiencing significant pressure to increase value of care by reducing costs while maintaining or improving patient-centered outcomes. Few studies have examined the cost-effectiveness cervical arthrodesis at a service level. Methods. A retrospective review of patients who underwent a primary 1-level ACDF by eight surgeons (four orthopedic and four neurosurgical) at a single academic institution between 2013 and 2015 was performed. Patients were identified by Diagnosis-Related Group and procedural codes. Patients with the ninth revision of the International Classification of Diseases coding for degenerative cervical pathology were included. Patients were excluded if they exhibited preoperative diagnoses or postoperative social work issues affecting their length of stay. Comparisons of preoperative demographics were performed using Student t tests and chi-squared analysis. Perioperative outcomes and costs for hospital services were compared using multivariate regression adjusted for preoperative characteristics. Results. A total of 137 patients diagnosed with cervical degeneration underwent single-level ACDF; 44 and 93 were performed by orthopedic surgeons and neurosurgeons, respectively. There was no difference in patient demographics. ACDF procedures performed by orthopedic surgeons demonstrated shorter operative times (89.1 ± 25.5 vs. 96.0 ± 25.5 min; P = 0.002) and higher laboratory costs (&Dgr;+

Improvements in Neck and Arm Pain Following an Anterior Cervical Discectomy and Fusion.

6.53 ± 

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

5.52 USD; P = 0.041). There were significant differences in operative time (P = 0.014) and labor costs (P = 0.034) between individual surgeons. There was no difference in total costs between specialties or individual surgeons. Conclusion. Surgical subspecialty training does not significantly affect total costs of ACDF procedures. Costs can, however, vary between individual surgeons based on operative times. Variation between individual surgeons highlights potential areas for improvement of the cost effectiveness of spinal procedures. Level of Evidence: 4

A Comparison of Narcotic Consumption Between Hospital and Ambulatory-Based Surgery Centers Following Anterior Cervical Discectomy and Fusion

Study Design. A retrospective analysis. Objective. The aim of this study was to quantify improvements in Visual Analogue Scale (VAS) neck and arm pain, Neck Disability Index (NDI), and Short Form-12 (SF-12) Mental (MCS) and Physical (PCS) Composite scores following an anterior cervical discectomy and fusion (ACDF). Summary of Background Data. ACDF is evaluated with patient-reported outcomes. However, the extent to which these outcomes improve following ACDF remains poorly defined. Methods. A surgical registry of patients who underwent primary, one- or two-level ACDF during 2013 to 2015 was reviewed. Comparisons of VAS neck and arm, NDI, and SF-12 MCS and PCS scores were performed using paired t tests from preoperative to each postoperative time point. Analysis of variance (ANOVA) was used to estimate the reduction in neck and arm pain over the first postoperative year. Subgroup analyses were performed for patients with predominant neck (pNP) or arm (pAP) pain, as well as for one- versus two-level ACDF. Results. Eighty-nine patients were identified. VAS neck and arm, NDI, and SF-12 PCS improved from preoperative scores at all postoperative time points (P < 0.05 for each). Across the first postoperative year, patients reported a 2.7-point (44.2%) reduction in neck and a 3.1-point (54.0%) reduction in arm pain (P < 0.05 for each). Sixty-one patients with pNP and 28 patients with pAP reported reductions in neck and arm pain over the first 6 months and 12 weeks postoperatively, respectively (P < 0.05 for each). Patients who underwent one-level ACDFs experienced a 47.2% reduction in neck pain and 55.1% reduction in arm pain over the first postoperative year (P < 0.05 for each), while those undergoing two-level ACDF experienced 39.7% and 49.2% for neck and arm, respectively (P < 0.05 for each). Conclusion. This study suggests that patients experience significant improvements in neck and arm pain following ACDF regardless of presenting symptom. In addition, patients undergoing one-level ACDF report greater reductions in neck and arm pain than patients undergoing two-level fusion. Level of Evidence: 4