Efficient Delivery of Nerve Growth Factors to the Central Nervous System for Neural Regeneration.

The central nervous system (CNS) plays a central role in the control of sensory and motor functions, and the disruption of its barriers can result in severe and debilitating neurological disorders. Neurotrophins are promising therapeutic agents for neural regeneration in the damaged CNS. However, their penetration across the blood-brain barrier remains a formidable challenge, representing a bottleneck for brain and spinal cord therapy. Herein, a nanocapsule-based delivery system is reported that enables intravenously injected nerve growth factor (NGF) to enter the CNS in healthy mice and nonhuman primates. Under pathological conditions, the delivery of NGF enables neural regeneration, tissue remodeling, and functional recovery in mice with spinal cord injury. This technology can be utilized to deliver other neurotrophins and growth factors to the CNS, opening a new avenue for tissue engineering and the treatment of CNS disorders and neurodegenerative diseases.

A Bioinspired Platform for Effective Delivery of Protein Therapeutics to the Central Nervous System.

Central nervous system (CNS) diseases are the leading cause of morbidity and mortality; their treatment, however, remains constrained by the blood-brain barrier (BBB) that impedes the access of most therapeutics to the brain. A CNS delivery platform for protein therapeutics, which is achieved by encapsulating the proteins within nanocapsules that contain choline and acetylcholine analogues, is reported herein. Mediated by nicotinic acetylcholine receptors and choline transporters, such nanocapsules can effectively penetrate the BBB and deliver the therapeutics to the CNS, as demonstrated in mice and non-human primates. This universal platform, in general, enables the delivery of any protein therapeutics of interest to the brain, opening a new avenue for the treatment of CNS diseases.

Surgical Treatment of Recurrent Lumbar Disk Herniation: A Systematic Review and Meta-analysis.

Consensus is lacking regarding optimal surgical treatment of recurrent lumbar disk herniation. A systematic search of multiple databases was conducted for studies evaluating outcomes after treatment for recurrent lumbar disk herniation. Treatment options included decompression surgeries and fusion surgeries. Although fusion surgeries eliminated re-recurrence of disk herniation, this coincided with higher incidences of complications and reoperation. Decompression surgeries and fusion surgeries both resulted in improvements in Japanese Orthopaedic Association, Oswestry Disability Index, and visual analog scale back and leg scores postoperatively (P<.05). The complication risk profiles of decompression surgeries and fusion surgeries must be balanced with the risk of disk herniation re-recurrence, as both procedures lead to improvements in functional outcomes. [Orthopedics. 2018; 41(4):e457-e469.].

Vertebral Augmentation is Superior to Nonoperative Care at Reducing Lower Back Pain for Symptomatic Osteoporotic Compression Fractures: A Meta-Analysis.

STUDY DESIGN: This is a systematic review and meta-analysis. OBJECTIVE: This study's goal was to (i) assess the clinical outcomes with and without vertebral augmentation (VA) for osteoporotic vertebral compression fractures (VCFs) with versus without correlating signs and symptoms; and (ii) acute (symptoms <3 mo duration) and subacute VCFs (3-6 mo duration) versus chronic VCFs (>6 mo). SUMMARY OF BACKGROUND DATA: Previously, a randomized controlled trial in the New England Journal of Medicine concluded that vertebroplasty for osteoporotic VCFs provided no clinical benefit over sham surgery. However, the VCFs examined had no clinical correlation with symptom, physical examination, or imaging (magnetic resonance imaging/bone scan) findings. Nonetheless, the randomized controlled trial resulted in a reduction in VA performed in the United States. Currently, no consensus exists on VA versus nonoperative care for symptomatic VCFs (SVFs). MATERIALS AND METHODS: A literature search was conducted for studies on VA and conservative management for VCFs. Meta-analysis was performed using the random-effects model. The primary outcome was improvement in lower back pain visual analog score. SVFs were defined as radiographic VCF with clinical correlation. Radiographic-alone VCF (RVF) was defined as radiographic VCF without clinical correlation. RESULTS: Thirteen studies totaling 1467 patients with minimum 6-month follow-up were found. Pain reduction was greater with VA over conservative management for SVFs (P<0.000001) and equivalent for RVFs (P=0.22). Subanalysis for acute/subacute SVFs and chronic SVFs showed that VA was superior to nonoperative care (P=0.0009 and 0.04, respectively). No difference was observed in outcomes between VA and nonoperative care for chronic RVF (P=0.22). CONCLUSIONS: VA is superior to nonoperative care in reducing lower back pain for osteoporotic VCFs with correlating signs and symptoms. VA had no benefit over nonoperative care for chronic VCFs that lacked clinical correlation. Lower back pain has many etiologies and patients should be clinically assessed before recommending VA.

Accuracy and Safety of Percutaneous Lumbosacral Pedicle Screw Placement Using Dual-Planar Intraoperative Fluoroscopy.

STUDY DESIGN: Retrospective case series with prospective arm. PURPOSE: To assess the safety and accuracy of percutaneous lumbosacral pedicle screw placement (PLPSP) in the lumbosacral spine using intraoperative dual-planar fluoroscopy (DPF). OVERVIEW OF LITERATURE: There are several techniques available for achieving consistent, safe, and accurate results with PLPSP. There is a paucity of literature describing the beneficial operative, economic, and clinical outcomes of DPF, the most readily accessible image guidance system. METHODS: From 2004 to 2014, 451 consecutive patients underwent PLPSP using DPF, for a total of 2,345 screw placement. The results of prospectively obtained postoperative computed tomography (CT) examinations of an additional 41 consecutive patients were compared with the results of 104 CT examinations obtained postoperatively due to clinical symptomatology; these results were interpreted by three reviewers. The rates of revision indicated by misplaced screws with consistent clinical symptomatology were compared between groups. Pedicle screw placement was graded according to 2-mm increments in medial pedicle wall breach and measurement of screw axis placement. RESULTS: Seven of the 2,345 pedicle screws placed percutaneously with the use of the dual-planar fluoroscopic technique required revision because of a symptomatic misplaced screw, for a screw revision rate of 0.3%. There were no statistically significant demographic differences between patients who had screws revised and those who did not. All screws registered greater than 10 mA on electromyographic stimulation. In the 41 prospectively obtained CT examinations, one out of 141 screws (0.7%) was revised due to pedicle wall breach; whereas among the 104 patients with 352 screws, three screws were revised (0.9%). CONCLUSIONS: DPF is an extremely accurate, safe, and reproducible technique for placement of percutaneous pedicle screws and is a readily available and cost-effective alternative to CT-guided pedicle screw placement techniques. Postoperative CT evaluation is not necessary with PLPSP unless the patient is symptomatic. Acceptable electromyographic thresholds may need to be reevaluated.

The Effect of Ketorolac on Thoracolumbar Posterolateral Fusion: A Systematic Review and Meta-Analysis.

STUDY DESIGN: Systematic review and meta-analysis. OBJECTIVE: The purpose of this study was to evaluate the effect of postoperative ketorolac administration (ie, dosage and duration of use) on pseudarthrosis following thoracolumbar posterolateral spinal fusions. SUMMARY OF BACKGROUND DATA: Ketorolac is a nonsteroidal anti-inflammatory drug often administered for pain control after spine surgery. The main concern with ketorolac is the risk of pseudarthrosis following fusion. MATERIALS AND METHODS: A systematic search of multiple medical reference databases was conducted for studies detailing postoperative ketorolac use in lumbar fusion and scoliosis surgery in adult and pediatric patients, respectively. Meta-analysis was performed using the random-effects model for heterogeneity as this study analyzes heterogenous patient populations undergoing variable approaches to fusion and variable numbers of levels with variable means of detection of pseudarthrosis. Outcome measure was pseudarthrosis. RESULTS: Overall, 6 studies totaling 1558 patients were reviewed. Pseudarthrosis was observed in 119 (7.6%) patients. Pseudarthrosis were observed in adults with ketorolac administered for >2 days [odds ratio (OR), 3.44, 95% confidence interval (95% CI), 1.87-6.36; P<0.001], adults with doses of ≥120 mg/d (OR, 2.93, 95% CI, 1.06-8.12; P=0.039), and adults with ketorolac administered for >2 days and at doses ≥120 mg/d (OR, 4.75, 95% CI, 2.34-9.62; P<0.001). Ketorolac use in smokers was associated with pseudarthrosis (OR, 8.71, 95% CI, 2.23-34.0; P=0.002). CONCLUSION: Ketorolac, when administered for >2 days and/or at a dose of ≥120 mg/d, is associated with pseudarthrosis in adults after posterolateral lumbar fusion. Ketorolac use in smokers is also associated with pseudarthrosis.

Efficacy of Vertebral Augmentation for Vertebral Compression Fractures: A Review of Meta-Analyses.

INTRODUCTION: Vertebral compression fracture incidence is rising with the growth of the geriatric population and is one of the leading disabilities in healthcare. However, the literature is conflicted on the benefits of vertebral augmentation versus nonoperative care for these fractures. The purpose of the current study was to perform a review of all meta-analyses in the literature comparing vertebral augmentation to nonoperative care and descriptively report the results. METHODS: A review of all meta-analyses evaluating trials of vertebral augmentation compared with nonoperative care was performed. The primary outcome studied was pain. Secondary outcomes were quality of life (QoL) metrics and functional outcomes. RESULTS: Ten studies met the inclusion criteria. Besides two sham procedure studies, the remaining literature concluded that vertebral augmentation was superior to nonoperative care for reducing back pain. The reporting of secondary outcomes, such as QoL metrics and functional outcomes, was heterogeneous among the studies. Studies that reported these secondary outcomes, however, did identify some early benefit in vertebral augmentation. CONCLUSIONS: The current literature suggests vertebral augmentation is more effective in improving pain outcomes compared with nonoperative management. While more studies are needed to conclusively assess vertebral augmentation's efficacy in improving functional outcome and QoL, the meta-analyses surveyed here suggest that at least some benefit exists when assessing these two outcomes.

The Utility of Preoperative Magnetic Resonance Imaging for Determining the Flexibility of Sagittal Imbalance.

BACKGROUND: Scoliosis X-rays are the gold standard for assessing preoperative lumbar lordosis; however, particularly for flexible lumbar deformities, it is difficult to predict from these images the extent of correction required, as standing radiographs cannot predict the thoracolumbar alignment after intraoperative positioning. OBJECTIVE: To determine the utility of preoperative MRI in surgical planning for patients with flexible sagittal imbalance. METHODS: We identified 138 patients with sagittal imbalance. Radiographic parameters including pelvic incidence and lumbar lordosis were obtained from images preoperatively. RESULTS: The mean difference was 2.9° between the lumbar lordosis measured on supine MRI as compared to the intraoperative X-rays, as opposed to 5.53° between standing X-rays and intraoperative X-ray. In patients with flexible deformities (n = 24), the lumbar lordosis on MRI measured a discrepancy of 3.08°, as compared to a discrepancy of 11.46° when measured with standing X-ray. CONCLUSION: MRI adequately determined which sagittal deformities were flexible. Furthermore, with flexible sagittal deformities, lumbar lordosis measured on MRI more accurately predicted the intraoperative lumbar lordosis than that measured on standing X-ray. The ability to preoperatively predict intraoperative lumbar lordosis with positioning helps with surgical planning and patient counseling regarding expectations and risks of surgery.

Radiographic and Clinical Outcomes of Anterior and Transforaminal Lumbar Interbody Fusions: A Systematic Review and Meta-analysis of Comparative Studies.

STUDY DESIGN: Systematic review and meta-analysis. OBJECTIVE: Compare the radiographic and clinical outcomes of anterior lumbar interbody fusion (ALIF) to transforaminal lumbar interbody fusion (TLIF). SUMMARY OF BACKGROUND DATA: ALIF and TLIF are 2 methods of achieving spinal arthrodesis. There are conflicting reports with no consensus on the optimal interbody technique to achieve successful radiographic and clinical outcomes. The goal of this systematic review and meta-analysis was to compare the radiographic and clinical outcomes of ALIF to TLIF. MATERIALS AND METHODS: A systematic search of multiple medical reference databases was conducted for studies comparing ALIF to TLIF. Studies that included stand-alone ALIFs were excluded. Meta-analysis was performed using the random-effects model for heterogeneity. Radiographic outcome measures included segmental and overall lumbar lordosis, and fusion rates. Clinical outcomes measures included Oswestry disability index (ODI) and visual analog scale (VAS) score for back pain. RESULTS: The search yielded 7 studies totaling 811 patients (ALIF=448, TLIF=363). ALIF was superior to TLIF in restoring segmental lumbar lordosis at L4-L5 and L5-S1 (L4-L5; P=0.013, L5-S1; P<0.001). ALIF was also superior to TLIF in restoring overall lumbar lordosis (P<0.001). However, no significant differences in fusion rates were noted between both techniques [odds ratio=0.905; 95% confidence interval, 0.458-1.789; P=0.775]. In addition, ALIF and TLIF were comparable with regards to ODI and VAS scores (ODI; P=0.184, VAS; P=0.983). CONCLUSIONS: For the restoration of lumbar lordosis, ALIF is superior to TLIF. However, TLIF is comparable to ALIF with regards to fusion rate and clinical outcomes.

The Epidemiology of Vertebral Osteomyelitis in the United States From 1998 to 2013.

STUDY DESIGN: This is a epidemiological database analysis. OBJECTIVES: The objectives of this article are to assess the following characteristics of vertebral osteomyelitis (VO): (1) incidence and patient demographics, (2) mortality rate, (3) length-of-stay (LOS), and (4) admission costs. SUMMARY OF BACKGROUND: VO is a serious disease with potentially devastating clinical consequences. At present, there is limited data on the epidemiology of VO in the United States as previous reports are based on older studies with small sample sizes. METHODS: We used the Nationwide Inpatient Sample database and estimated that 228,044 patients were admitted for VO in the United States between 1998 and 2013. Data were extracted on patient demographics, comorbidities, inpatient mortality, LOS, and inflation-adjusted hospitalization charges. Multivariable regression analyses were performed. RESULTS: The incidence of VO admission was 4.8 per 100,000, increasing from 8021 cases (2.9/ 100,000) in 1998 to 16,917 cases (5.4/100,000) in 2013. Majority of patients were white (74%), male (51%), younger than 59 years of age (49.5%), and carried Medicare insurance (50%). The increase in incidence for male and females was similar. The mortality rate during hospital stay was 2.1%, decreasing from 2% in 1998 to 1.7% in 2006 and increasing to 2.2% in 2013. Risk factors for mortality included increased age, male sex, and higher comorbidity score. History of congestive heart failure [odds ratio (OR)=2.45], cerebrovascular disease (OR=1.92), liver disease (OR=2.33), hepatitis C (OR=2.36), and renal disease (OR=1.88) was associated with higher mortality rate. Mean LOS was 9.2 days, decreasing from 9.1 days in 1998 to 8.8 days in 2013. The mean estimated hospital charges for admission were $54,599, however, this increased from $24,102 in 1998 (total of $188.8 millions) to $80,786 in 2013 (total of $1.3 billions). CONCLUSION: This condition is associated with lengthy and expensive hospital stays resulting in a significant burden to patients and the health care system.

Effectiveness of Reoperations for Adjacent Segment Disease Following Lumbar Spinal Fusion.

Although several options are available to address adjacent segment disease (ASD), the most effective surgical treatment has not been determined. In addition, it is important to subdivide ASD into stenosis with or without instability to determine if a decompression alone vs an extension of fusion is necessary. A systematic search of multiple medical reference databases was conducted for studies on surgical treatment of ASD. The primary outcome measures used were radiographic and clinical success rates. Meta-analysis was completed to determine effect summary values, 95% confidence intervals, and Q statistic and I2 values, using the random effects model for heterogeneity. The search yielded 662 studies, of which 657 were excluded. A total of 5 (level IV) studies with a total of 118 patients were included in this review. In 2 studies (46 patients), stenosis without instability was the indication for reoperation for ASD. However, extension of fusion was the modality of choice for the treatment of ASD in all studies. Overall clinical improvement (in back and/or leg pain scores) was noted in 71.3% of patients (95% confidence interval, 37.4-100), while radiographic fusion was noted in 89.3% of patients (95% confidence interval, 51.2-100). Following reoperation for ASD, revision surgery rates ranged from 4.5% to 23.1% at last clinical follow-up. There is variability in the clinical improvement following lumbar fusion for ASD. In addition, little literature exists regarding the optimal treatment options for patients with ASD for stenosis with or without instability. [Orthopedics. 2018; 41(2):e161-e167.].

Pelvic retroversion: a compensatory mechanism for lumbar stenosis.

OBJECTIVE The flexed posture of the proximal (L1-3) or distal (L4-S1) lumbar spine increases the diameter of the spinal canal and neuroforamina and can relieve symptoms of neurogenic claudication. Distal lumbar flexion can result in pelvic retroversion; therefore, in cases of flexible sagittal imbalance, pelvic retroversion may be compensatory for lumbar stenosis and not solely compensatory for the sagittal imbalance as previously thought. The authors investigate underlying causes for pelvic retroversion in patients with flexible sagittal imbalance. METHODS One hundred thirty-eight patients with sagittal imbalance who underwent a total of 148 fusion procedures of the thoracolumbar spine were identified from a prospective clinical database. Radiographic parameters were obtained from images preoperatively, intraoperatively, and at 6-month and 2-year follow-up. A cohort of 24 patients with flexible sagittal imbalance was identified and individually matched with a control cohort of 23 patients with fixed deformities. Flexible deformities were defined as a 10° change in lumbar lordosis between weight-bearing and non-weight-bearing images. Pelvic retroversion was quantified as the ratio of pelvic tilt (PT) to pelvic incidence (PI). RESULTS The average difference between lumbar lordosis on supine MR images and standing radiographs was 15° in the flexible cohort. Sixty-eight percent of the patients in the flexible cohort were diagnosed preoperatively with lumbar stenosis compared with only 22% in the fixed sagittal imbalance cohort (p = 0.0032). There was no difference between the flexible and fixed cohorts with regard to C-2 sagittal vertical axis (SVA) (p = 0.95) or C-7 SVA (p = 0.43). When assessing for postural compensation by pelvic retroversion in the stenotic patients and nonstenotic patients, the PT/PI ratio was found to be significantly greater in the patients with stenosis (p = 0.019). CONCLUSIONS For flexible sagittal imbalance, preoperative attention should be given to the root cause of the sagittal misalignment, which could be compensation for lumbar stenosis. Pelvic retroversion can be compensatory for both the lumbar stenosis as well as for sagittal imbalance.

Intraoperative Neuromonitoring for Anterior Cervical Spine Surgery: What Is the Evidence?

STUDY DESIGN: Systematic review and meta-analysis. OBJECTIVE: The goal of this study was to (i) assess the risk of neurological injury after anterior cervical spine surgery (ACSS) with and without intraoperative neuromonitoring (ION) and (ii) evaluate differences in the sensitivity and specificity of ION for ACSS. SUMMARY OF BACKGROUND DATA: Although ION is used to detect impending neurological injuries in deformity surgery, it's utility in ACSS remains controversial. METHODS: A systematic search of multiple medical reference databases was conducted for studies on ION use for ACSS. Studies that included posterior cervical surgery were excluded. Meta-analysis was performed using the random-effects model for heterogeneity. Outcome measure was postoperative neurological injury. RESULTS: The search yielded 10 studies totaling 26,357 patients. The weighted risk of neurological injury after ACSS was 0.64% (0.23-1.25). The weighted risk of neurological injury was 0.20% (0.05-0.47) for ACDFs compared with 1.02% (0.10-2.88) for corpectomies. For ACDFs, there was no difference in the risk of neurological injury with or without ION (odds ratio, 0.726; confidence interval, CI, 0.287-1.833; P = 0.498). The pooled sensitivities and specificities of ION for ACSS are 71% (CI: 48%-87%) and 98% (CI: 92%-100%), respectively. Unimodal ION has a higher specificity than multimodal ION [unimodal: 99% (CI: 97%-100%), multimodal: 92% (CI: 81%-96%), P = 0.0218]. There was no statistically significant difference in sensitivities between unimodal and multimodal [68% vs. 88%, respectively, P = 0.949]. CONCLUSION: The risk of neurological injury after ACSS is low although procedures involving a corpectomy may carry a higher risk. For ACDFs, there is no difference in the risk of neurological injury with or without ION use. Unimodal ION has a higher specificity than multimodal ION and may minimize "subclinical" intraoperative alerts in ACSS. LEVEL OF EVIDENCE: 3.

Utility of Intraoperative Neuromonitoring for Lumbar Pedicle Screw Placement Is Questionable: A Review of 9957 Cases.

STUDY DESIGN: A retrospective database study. OBJECTIVE: The goal of this study was to (1) evaluate the trends in the use of electromyography (EMG) for instrumented posterolateral lumbar fusions (PLFs) in the United States and (2) assess the risk of neurological injury following PLFs with and without EMG. SUMMARY OF BACKGROUND DATA: Neurologic injuries from iatrogenic pedicle wall breaches during screw placement are known complications of PLFs. The routine use of intraoperative neuromonitoring (ION) such as EMG during PLF to improve the accuracy and safety of pedicle screw implantation remains controversial. METHODS: A retrospective review was performed using the PearlDiver Database to identify patients who had PLF surgery with and without EMG for lumbar disorders from years 2007 to 2015. Patients undergoing concomitant interbody fusions or spinal deformity surgery were excluded. Demographic trends and risk of neurological injuries were assessed. RESULTS: During the study period, 2007 to 2015, 9957 patients underwent PLFs. Overall, EMG was used in 2495 (25.1%) of these patients. There was a steady increase in the use of EMG from 14.9% in 2007 to 28.7% in 2009, followed by a steady decrease to 21.9% in 2015 (P < 0.0001). The risk of postoperative neurological injuries following PLFs was 1.35% (134/9957) with a risk of 1.36% (34/2495) with EMG and 1.34% (100/7462) without EMG (P = 0.932). EMG is used most commonly for PLFs in the Southern part of the United States. CONCLUSION: In this retrospective national database review, we found that there was a steady increase in the routine use of EMG for PLFs followed by a steady decline. Regional differences were observed in the utility of EMG for PLFs. The risk of neurological complications following PLF in the absence of spinal deformity is low and the routine use of EMG for PLF may not decrease the risk. LEVEL OF EVIDENCE: 4.

Clinical Differences Between Monomicrobial and Polymicrobial Vertebral Osteomyelitis.

Little literature exists examining differences in presentation and outcomes between monomicrobial and polymicrobial vertebral infections. Seventy-nine patients treated for vertebral osteomyelitis between 2001 and 2011 were reviewed. Patients were divided into monomicrobial and polymicrobial cohorts based on type of infection. Various characteristics were compared between the 2 groups. The 26 patients with a polymicrobial infection were older and had a higher mortality rate, lower clearance of infection, larger infection, more vertebral instability, higher erythrocyte sedimentation rate at presentation, and longer mean length of stay. There were no significant differences in Oswestry Disability Index scores at final follow-up, but there were differences in presentation and clinical outcomes between monomicrobial and polymicrobial vertebral osteomyelitis. Patients may benefit from counseling regarding their disease type and potential prognosis. [Orthopedics. 2017; 40(2):e370-e373.].

Routine Use of Intraoperative Neuromonitoring During ACDFs for the Treatment of Spondylotic Myelopathy and Radiculopathy Is Questionable: A Review of 15,395 Cases.

STUDY DESIGN: A retrospective database study. OBJECTIVE: The goal of this study was to (1) evaluate the trends in the use of intraoperative neuromonitoring (ION) for anterior cervical discectomy and fusion (ACDF) surgery in the United States and (2) assess the incidence of neurological injuries after ACDFs with and without ION. SUMMARY OF BACKGROUND DATA: Somatosensory-evoked potentials (SSEPs) and motor-evoked potentials (MEPs) are the commonly used ION modalities for ACDFs. Controversy exists on the routine use of ION for ACDFs and there is limited literature on national practice patterns of its use. METHODS: A retrospective review was performed using the PearlDiver Patient Record Database to identify cases of spondylotic myelopathy and radiculopathy that underwent ACDF from 2007 to 2014. The type of ION modality used and the rates of neurological injury after surgery were assessed. RESULTS: During the study period, 15,395 patients underwent an ACDF. Overall, ION was used in 2627 (17.1%) of these cases. There was a decrease in the use of ION for ACDFs from 22.8% in 2007 to 4.3% use in 2014 (P < 0.0001). The ION modalities used for these ACDFs were quite variable: SSEPs only (48.7%), MMEPs only (5.3%), and combined SSEPs and MMEPs (46.1%). Neurological injuries occurred in 0.23% and 0.27% of patients with and without ION, respectively (P = 0.84). Younger age was associated with a higher utility of ION (<45: 20.3%, 45-54: 19.3%, 55-64: 16.6%, 65-74: 14.3%, and >75: 13.6%, P < 0.0001). Significant regional variability was observed in the utility of ION for ACDFs across the country (West; 21.9%, Midwest; 12.9% (P < 0.0001). CONCLUSION: There has been a significant decrease in the use of ION for ACDFs. Furthermore, there was significant age and regional variability in the use of ION for ACDFs. Use of ION does not further prevent the rate of postoperative neurological complications for ACDFs as compared with the cases without ION. The utility of routine ION for ACDFs is questionable. LEVEL OF EVIDENCE: 3.

Delay in Diagnosis of Vertebral Osteomyelitis Affects the Utility of Cultures.

INTRODUCTION: Obtaining blood or tissue cultures prior to administration of antibiotics has been the standard of care in the treatment of osteomyelitis of the spine. A delay in diagnosis of vertebral osteomyelitis is the primary culprit for the inaccuracy of blood cultures and biopsies. The purpose of this study was to evaluate the outcomes of spinal osteomyelitis in patients where the infecting organism was identified through cultures in contrast to cases where the cultures continued to be negative. MATERIALS AND METHODS: We retrospectively reviewed the database of spinal osteomyelitis cases presented at a high-volume institution from 2001-2011. This resulted in 91 patients (51 men and 40 women) who had a mean age of 59 years with a mean follow-up of four years. Delay in diagnosis was defined as greater than 2.5 months from first ER visit for non-specific back pain to diagnosis of osteomyelitis without antibiotic treatment in the interim. Nineteen patients had a delay in diagnosis (DD) and 72 were diagnosed early (ED). Outcomes evaluated include clearance of infection, clinical outcomes measured by Oswestry disability index scores (ODIs), and the efficacy of blood cultures and biopsies. RESULTS: The ED group had a higher odds ratio of osteomyelitis clearance compared to the delay in diagnosis group and this trended toward significance [p=0.08]. The mean improvements in ODIs were significantly greater in the ED group compared to the DD group. Positive blood cultures were more positive when drawn within one month compared to after one month [p=.001]. Percutaneous biopsy cultures were more positive when drawn within 2.5 months compared to after 2.5 months [p=.025]. Open biopsy cultures were more positive when drawn within 4.5 months compared to after that [p<0.001]. DISCUSSION: We found that delayed diagnosis may negatively affect the treatment outcome as evidenced by the greater improvements in ODI scores among those diagnosed early. Although we were unable to show a difference in clearance between early and delayed diagnosis, it is quite possible that larger cohorts may have shown this given the trend toward significance. CONCLUSION: Hence, an early diagnosis has improved vertebral osteomyelitis clearance and clinical outcomes, and blood cultures and biopsies may have a low yield if delayed.

When Do You Drain Epidural Abscesses of the Spine?

BACKGROUND: How the relative volume of an epidural abscess on MRI affects outcomes with antibiotics alone has limited literature. The purpose of this study was to identify which infected epidural collections will reabsorb with antibiotics alone. Specifically, what is the critical size and enhancement on contrast MRIs to require a drainage procedure? MATERIALS AND METHODS: A retrospective review of all spinal osteomyelitis patients from 2001-2012 was performed. Inclusion criteria included appropriate initial imaging, lab results, no drainage procedures of collections, and no treatment prior to admission at an outside institution. Large size epidural abscess was defined as abscesses with a volume greater than 1400 mm3. Clearance and mortality rates were evaluated. RESULTS: The cohort consisted of 128 patients including 76 men and 52 women who had a mean age of 62 years (range, 21 to 90 years) and had a mean follow-up of 38 months (range, 24 to 72 months). Patients with a large epidural abscess had a greater clearance rate of the infection and decreased mortality rate when treated with surgery or drainage compared to patients treated with antibiotics alone [clearance: p=0.048; mortality: p=0.048]. Those small epidural abscesses had similar clearance and mortality rates when treated with surgery or drainage compared to antibiotics alone [clearance: p=0.75; mortality: p=0.13]. Patients with non-enhancing epidural abscesses had similar clearance rates-but increased mortality rates-when treated with antibiotics alone compared to surgery or drainage [clearance: p>0.9; mortality: p=0.03]. Those with enhancing epidural collections had similar clearance and mortality rates when treated with antibiotics alone compared to surgery or drainage [clearance: p=0.08, mortality: p=0.10]. CONCLUSION: Large epidural infected collections require surgery or a percutaneous drainage procedure. Clearance rates are higher and mortality rates are lower compared to non-operative management in these instances. Neurologically intact patients with a small epidural collection can be treated with antibiotics alone with good expected outcomes.