Correction to: Radiation exposure to the surgeon during minimally invasive spine procedures is directly estimated by patient dose.

Unfortunately, the first author surname was incorrectly published as "Harrison Farber" instead of "Farber" in original publication.

Radiation exposure to the surgeon during minimally invasive spine procedures is directly estimated by patient dose.

PURPOSE: Radiation exposure is a necessary component of minimally invasive spine procedures to augment limited visualization of anatomy. The surgeon's exposure to ionizing radiation is not easily recognizable without a digital dosimeter-something few surgeons have access to. The aim of this study was to identify an easy alternative method that uses the available radiation dose data from the C-arm to accurately predict physician exposure. METHODS: The senior surgeon wore a digital dosimeter during all minimally invasive spine fusion procedures performed over a 12-month period. Patient demographics, procedure information, and radiation exposure throughout the procedure were recorded. RESULTS: Fifty-five minimally invasive spine fusions utilizing 330 percutaneous screws were included. Average radiation dose was 0.46 Rad/screw to the patient. Average radiation exposure to the surgeon was 1.06 ± 0.71 µSv/screw, with a strong positive correlation (r = 0.77) to patient dose. The coefficient of determination (r2) was 0.5928, meaning almost two-thirds of the variability in radiation exposure to the surgeon is explained by radiation exposure to the patient. CONCLUSIONS: Intra-operative radiation exposure to the patient, which is easily identifiable as a continuously updated fluoroscopic monitor, is a reliable predictor of radiation exposure to the surgeon during percutaneous screw placement in minimally invasive spinal fusion surgery and therefore can provide an estimate of exposure without the use of a dosimeter. With this, a surgeon can better understand the magnitude of their exposure on a case-by-case basis rather than on a quarterly basis, or more likely, not at all. These slides can be retrieved under Electronic Supplementary Material.

Laminoplasty versus laminectomy with fusion for the treatment of spondylotic cervical myelopathy: short-term follow-up.

BACKGROUND CONTEXT: Laminoplasty and laminectomy with fusion are two common procedures for the treatment of cervical spondylotic myelopathy. Controversy remains regarding the superior surgical treatment. PURPOSE: To compare short-term follow-up of laminoplasty to laminectomy with fusion for the treatment of cervical spondylotic myelopathy. STUDY DESIGN/SETTING: Retrospective review comparing all patients undergoing surgical treatment for cervical spondylotic myelopathy by a single surgeon. PATIENT SAMPLE: All patients undergoing laminoplasty or laminectomy with fusion by a single surgeon over a 5-year period (2007-2011). OUTCOME MEASURES: Cervical alignment and range of motion on pre- and post-operative radiographs and clinical outcome measures including Japanese Orthopaedic Association (JOA) scores, neck disability index (NDI), short form-12 mental (SF-12M) and physical (SF-12P) composite scores and visual analog pain scores for neck (VAS-N) and arm (VAS-A). METHODS: Patients undergoing laminoplasty or laminectomy with fusion by a single surgeon were reviewed. Cohorts of 41 laminoplasty patients and 31 laminectomy with fusion patients were selected based on strict criteria. The cohorts were well matched based on pre-operative clinical scores, radiographic measurements, and demographics. The average follow-up was 19.2 months for laminoplasty and 18.2 months for laminectomy with fusion. Evaluated outcomes included Japanese Orthopaedic Association (JOA) score, neck disability index (NDI), short form-12 (SF-12), visual analog pain scores (VAS), cervical sagittal alignment, cervical range of motion, length of stay, cost and complications. RESULTS: The improvement in JOA, SF-12 and VAS scores was similar in the two cohorts after surgery. There was no significant change in cervical sagittal alignment in either cohort. Range-of-motion decreased in both cohorts, but to a greater degree after laminectomy with fusion. C5 nerve root palsy and infection were the most common complications in both cohorts. Laminectomy with fusion was associated with a higher rate of C5 nerve root palsy and overall complications. The average hospital length of stay and cost were significantly less with laminoplasty. CONCLUSIONS: This study provides evidence that laminoplasty may be superior to laminectomy with fusion in preserving cervical range of motion, reducing hospital stay and minimizing cost. However, the significance of these differences remains unclear, as laminoplasty clinical outcome scores were generally comparable to laminectomy with fusion.

Influence of perioperative complication severity on 1- and 2-year outcomes of low back surgery.

BACKGROUND: Several factors potentially influence outcomes of surgery, including perioperative complications. Complications may take many forms and the Clavien-Dindo (CD) classification is designed to categorize them by degree of severity. The aim of this study was to evaluate the influence of perioperative complications by severity categorization on the 1-and 2-year pain and disability outcomes for patients who received low back surgery. MATERIALS AND METHODS: Data used for the study involved a purposive sample (N = 477; 8.1%) from a spine outcomes registry of 5876 patients who received spine surgery and encountered complications. All complications were categorized using the CD classification and were collapsed according to distribution frequencies, i.e., Grade I-II and Grade III-V. Adjusted and unadjusted regression analyses were used to determine the association between CD classification and 1- and 2-year outcomes. RESULTS: The majority of surgical complications were Grade III-V (N = 358; 75.1%), with two incidences in which death occurred. For the unadjusted models, there were no significant associations between CD classification categorizations for 1-year outcomes; however, 2-year outcomes were significantly worse (P <0.05) for those with Grade III-V categorization. When adjusted and controlled for baseline characteristics, CD classification did not influence 1-or 2-year pain and disability outcomes. CONCLUSIONS: When control variables are considered, the severity of perioperative surgical complications does not appear to influence 1- or 2-year pain and disability outcomes. LEVEL OF EVIDENCE: Level 4.

Can triggered electromyography monitoring throughout retraction predict postoperative symptomatic neuropraxia after XLIF? Results from a prospective multicenter trial.

PURPOSE: This multicenter study aims to evaluate the utility of triggered electromyography (t-EMG) recorded throughout psoas retraction during lateral transpsoas interbody fusion to predict postoperative changes in motor function. METHODS: Three hundred and twenty-three patients undergoing L4-5 minimally invasive lateral interbody fusion from 21 sites were enrolled. Intraoperative data collection included initial t-EMG thresholds in response to posterior retractor blade stimulation and subsequent t-EMG threshold values collected every 5 min throughout retraction. Additional data collection included dimensions/duration of retraction as well as pre-and postoperative lower extremity neurologic exams. RESULTS: Prior to expanding the retractor, the lowestt-EMG threshold was identified posterior to the retractor in 94 % of cases. Postoperatively, 13 (4.5 %) patients had a new motor weakness that was consistent with symptomatic neuropraxia (SN) of lumbar plexus nerves on the approach side. There were no significant differences between patients with or without a corresponding postoperative SN with respect to initial posterior blade reading (p = 0.600), or retraction dimensions (p > 0.05). Retraction time was significantly longer in those patients with SN vs. those without (p = 0.031). Stepwise logistic regression showed a significant positive relationship between the presence of new postoperative SN and total retraction time (p < 0.001), as well as change in t-EMG thresholds over time (p < 0.001), although false positive rates (increased threshold in patients with no new SN) remained high regardless of the absolute increase in threshold used to define an alarm criteria. CONCLUSIONS: Prolonged retraction time and coincident increases in t-EMG thresholds are predictors of declining nerve integrity. Increasing t-EMG thresholds, while predictive of injury, were also observed in a large number of patients without iatrogenic injury, with a greater predictive value in cases with extended duration. In addition to a careful approach with minimal muscle retraction and consistent lumbar plexus directional retraction, the incidence of postoperative motor neuropraxia may be reduced by limiting retraction time and utilizing t-EMG throughout retraction, while understanding that the specificity of this monitoring technique is low during initial retraction and increases with longer retraction duration.

Predictors of pain and disability outcomes in one thousand, one hundred and eight patients who underwent lumbar discectomy surgery.

BACKGROUND: A key component toward improving surgical outcomes is proper patient selection. Improved selection can occur through exploration of prognostic studies that identify variables which are associated with good or poorer outcomes with a specific intervention, such as lumbar discectomy. To date there are no guidelines identifying key prognostic variables that assist surgeons in proper patient selection for lumbar discectomy. The purpose of this study was to identify baseline characteristics that were related to poor or favourable outcomes for patients who undergo lumbar discectomy. In particular, we were interested in prognostic factors that were unique to those commonly reported in the musculoskeletal literature, regardless of intervention type. METHODS: This retrospective study analysed data from 1,108 patients who underwent lumbar discectomy and had one year outcomes for pain and disability. All patient data was part of a multicentre, multi-national spine repository. Ten relatively commonly captured data variables were used as predictors for the study: (1) age, (2) body mass index, (3) gender, (4) previous back surgery history, (5) baseline disability, unique baseline scores for pain for both (6) low back and (7) leg pain, (8) baseline SF-12 Physical Component Summary (PCS) scores, (9) baseline SF-12 Mental Component Summary (MCS) scores, and (10) leg pain greater than back pain. Univariate and multivariate logistic regression analyses were run against one year outcome variables of pain and disability. RESULTS: For the multivariate analyses associated with the outcome of pain, older patients, those with higher baseline back pain, those with lesser reported disability and higher SF-12 MCS quality of life scores were associated with improved outcomes. For the multivariate analyses associated with the outcome of disability, presence of leg pain greater than back pain and no previous surgery suggested a better outcome. CONCLUSIONS: For this study, several predictive variables were either unique or conflicted with those advocated in general prognostic literature, suggesting they may have value for clinical decision making for lumbar discectomy surgery. In particular, leg pain greater than back pain and older age may yield promising value. Other significant findings such as quality of life scores and prior surgery may yield less value since these findings are similar to those that are considered to be prognostic regardless of intervention type.

Clinical identifiers for detecting underlying closed cervical fractures.

BACKGROUND: Although uncommon, closed cervical fractures (CCFs) may present in orthopedic clinical settings despite previous workup. The objective of this study was to describe the characteristics associated with missed CCF. METHODS: The study was a retrospective database exploration of a cohort of subjects within a department of surgery with cervical pain. The sample consisted of 162 patients seen for a surgical consult for a number of cervical conditions. The examination time frame represented a clinical examination and imaging confirmation of diagnosis after an original initial visit by another provider. Descriptive and diagnostic accuracy values including sensitivity/specificity and positive/negative likelihood ratios (LR+/LR-) were calculated for each targeted variable. Clustered analyses were calculated using the patient history and situational characteristics. RESULTS: Eleven patients in the sample were diagnosed with CCF (6.7%). Six variables were significantly associated with a missed CCF. Using these six variables, it was found that failure to exhibit a condition of 2 of the 6 variables (1 or fewer) was the strongest in ruling out the condition (LR- = 0.0; post-test probability with a negative finding = 0%), whereas a finding of 4 of 6 was the most diagnostic for ruling in the condition (LR+ = 32; post-test probability with a positive finding = 70%). CONCLUSIONS: The findings in this sample suggest that select patient history or situational factors are still useful even after initial examination and clinicians must stay vigilant because CCFs may be missed during emergent care screens.

Clinical outcomes of extreme lateral interbody fusion in the treatment of adult degenerative scoliosis.

INTRODUCTION: The use of extreme lateral interbody fusion (XLIF) and other lateral access surgery is rapidly increasing in popularity. However, limited data is available regarding its use in scoliosis surgery. The objective of this study was to evaluate the clinical outcomes of adults with degenerative lumbar scoliosis treated with XLIF. METHODS: Thirty consecutive patients with adult degenerative scoliosis treated by a single surgeon at a major academic institution were followed for an average of 14.3 months. Interbody fusion was completed using the XLIF technique with supplemental posterior instrumentation. Validated clinical outcome scores were obtained on patients preoperatively and at most recent follow-up. Complications were recorded. RESULTS: The study group demonstrated improvement in multiple clinical outcome scores. Oswestry Disability Index scores improved from 24.8 to 19.0 (P < 0.001). Short Form-12 scores improved, although the change was not significant. Visual analog scores for back pain decreased from 6.8 to 4.6 (P < 0.001) while scores for leg pain decreased from 5.4 to 2.8 (P < 0.001). A total of six minor complications (20%) were recorded, and two patients (6.7%) required additional surgery. CONCLUSIONS: Based on the significant improvement in validated clinical outcome scores, XLIF is effective in the treatment of adult degenerative scoliosis.

Investigation of nonmechanical findings during spinal movement screening for identifying and/or ruling out metastatic cancer.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To investigate the diagnostic accuracy of lumbar movement restrictions and pain in patients with metastatic bone cancer. BACKGROUND: When evaluating patients with low back pain, physical therapists have used the presence of nonmechanical findings during a spinal movement screen as 1 factor in determining whether physician referral is necessary. There are no studies that have investigated the accuracy of this strategy in a situation of diagnostic uncertainty. METHODS: This study included 1,109 patients (655 women) with low back pain (mean age=54.8±16.3 years) seen at a spine surgery center who received a clinical movement screen and an imaging-supported diagnosis by an orthopedic surgeon. No report of pain during movement and no limitation of movement were considered the 2 targeted findings as these are associated with nonmechanical findings. RESULTS: Sixty-six patients were diagnosed with metastatic cancer, 61 with metastatic bone cancer and concomitant diagnoses. Pain-free lumbar movements in all directions for patients with metastatic bone cancer without concomitant diagnoses were associated with a posttest probability of 0.00 (+likelihood ratio=2.4; -likelihood ratio=0.0), which may be useful in ruling out spinal cancer. In situations where a concomitant diagnosis was present with cancer, the value of a movement screen was poor. CONCLUSION: Nonmechanical findings during a traditional movement screen are not specific to sinister conditions such as metastatic spinal cancer. Clinicians should expect concomitant conditions to exhibit painful or limited findings in patients with and without cancer.

Proinflammatory cytokine expression profile in degenerated and herniated human intervertebral disc tissues.

OBJECTIVE: Prior reports document macrophage and lymphocyte infiltration with proinflammatory cytokine expression in pathologic intervertebral disc (IVD) tissues. Nevertheless, the role of the Th17 lymphocyte lineage in mediating disc disease remains uninvestigated. We undertook this study to evaluate the immunophenotype of pathologic IVD specimens, including interleukin-17 (IL-17) expression, from surgically obtained IVD tissue and from nondegenerated autopsy control tissue. METHODS: Surgical IVD tissues were procured from patients with degenerative disc disease (n = 25) or herniated IVDs (n = 12); nondegenerated autopsy control tissue was also obtained (n = 8) from the anulus fibrosus and nucleus pulposus regions. Immunohistochemistry was performed for cell surface antigens (CD68 for macrophages, CD4 for lymphocytes) and various cytokines, with differences in cellularity and target immunoreactivity scores analyzed between surgical tissue groups and between autopsy control tissue regions. RESULTS: Immunoreactivity for IL-4, IL-6, IL-12, and interferon-gamma (IFNgamma) was modest in surgical IVD tissue, although expression was higher in herniated IVD samples and virtually nonexistent in control samples. The Th17 lymphocyte product IL-17 was present in >70% of surgical tissue fields, and among control samples was detected rarely in anulus fibrosus regions and modestly in nucleus pulposus regions. Macrophages were prevalent in surgical tissues, particularly herniated IVD samples, and lymphocytes were expectedly scarce. Control tissue revealed lesser infiltration by macrophages and a near absence of lymphocytes. CONCLUSION: Greater IFNgamma positivity, macrophage presence, and cellularity in herniated IVDs suggests a pattern of Th1 lymphocyte activation in this pathology. Remarkable pathologic IVD tissue expression of IL-17 is a novel finding that contrasts markedly with low levels of IL-17 in autopsy control tissue. These findings suggest involvement of Th17 lymphocytes in the pathomechanism of disc degeneration.

Extreme lateral interbody fusion approach for isolated thoracic and thoracolumbar spine diseases: initial clinical experience and early outcomes.

STUDY DESIGN: Retrospective review of prospective collected data on 22 patients. OBJECTIVE: To describe our initial clinical experience and outcomes with the extreme lateral interbody fusion (XLIF) approach for spinal diseases requiring access to the thoracic cavity. SUMMARY OF BACKGROUND DATA: Minimally invasive anterior approaches to the thoracic spine have traditionally consisted of thoracoscopic and mini-open thoracotomy techniques. We present our initial experience with employing the XLIF technique to treat thoracic spine diseases. METHODS: Clinical, radiographic, operative, postoperative, and functional outcomes were analyzed. RESULTS: A total of 22 patients (15 females, 7 males, average age 64.6 y) with isolated thoracic and thoracolumbar spine diseases were treated between 2005 and 2009. The indications for surgery included degenerative scoliosis (11), pathological fractures from tumors (2), adjacent level disease from prior fusions (5), thoracic disc herniations (3), and discitis/osteomyelitis (1). A total of 47 levels were treated. In the subset of patients treated for degenerative scoliosis, the mean preoperative and postoperative coronal Cobb angles were 22 and 14, respectively. The mean preoperative and postoperative sagittal angles were 39 and 44, respectively. The average estimated blood loss and length of stay were 227.5 mL and 4.8 d, respectively. Three complications consisting of wound infection, subsidence, and adjacent level disease requiring additional procedures were encountered. There were no neural, vascular, visceral injuries, or death. At a mean follow-up of 16.4 months (range, 3-50), we observed a 95.5% substantial clinical benefit. All patients who had reached a minimum of 6 months (95.5%) demonstrated radiographic evidence of fusion. CONCLUSIONS: The XLIF technique can be expanded to treat diseases in the thoracic spine. Although the magnitude of deformity correction achieved is less than that of the traditional open approaches, the lesser invasiveness of this technique may be tolerable for the elderly and in patients with significant medical comorbidities.

Clinical tests for screening and diagnosis of cervical spine myelopathy: a systematic review.

OBJECTIVE: The purpose of this review was to investigate the diagnostic accuracy for screening and confirmation of clinical tests for cervical spine myelopathy (CSM) and to investigate the quality of the studies that have investigated these values. METHODS: This study was a systematic review that used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Search terms for PubMed included myelopathy; diagnosis, differential; sensitivity and specificity; and physical examination. Search terms for Cumulative Index to Nursing and Allied Health Literature were limited to myelopathy and sensitivity and specificity. Qualitative assessment included report of diagnostic accuracy metrics (sensitivity, specificity, and positive and negative likelihood ratios) and quality scores using the Quality Assessment of Diagnostic Accuracy Studies tool. Scores were created for single tests and clustered test findings. RESULTS: After evaluation, 12 full-text articles were selected, scored, and tabulated. Nearly all of the 18 tests demonstrated high levels of specificity and low levels of sensitivity, suggesting that they are poor screening tools. Only one study was scored as high quality. One study involved clustering of test findings but was considered low quality. CONCLUSION: Nearly all of the clinical tests for CSM seem to be poor screening tools, which implies that manually oriented clinicians may perform treatment methods in a situation of doubt or uncertainly. More high-quality studies are needed, and manual therapists need to be cognizant that the current clinical tests for CSM lack strong diagnostic accuracy measures that are necessary for clinical decision making.

Differences in comorbidities on low back pain and low back related leg pain.

OBJECTIVE: Investigate the influence of external factors such as depression and BMI among subjects with primary severe low back pain (LBP) and low back related leg pain (LBLP). BACKGROUND: The report of disability in patients with LBP may be significantly influenced by confounding and moderating variables. No similar studies have examined the influence of these factors on LBLP. METHODS: This study included 1,448 consecutive subjects referred to a tertiary spine clinic. Unconditional binary logistic regression was used to determine the influence of comorbidities on the relationship between self-reported back and leg pain. A change in estimate formula was used to quantify this relationship. RESULTS: Among those subjects with primary LBP the unadjusted odds ratio was 8.58 (95% CI 4.87, 15.10) and when adjusting for BMI, depression and smoking was 5.94 (95% CI 3.04, 11.60) resulting in a 36.7% change due to confounding by these comorbidities. Among those with primary LBLP, the unadjusted odds ratio was 4.49 (95% CI 2.78, 7.27) and when adjusting for BMI and depression was 4.60 (95% CI 2.58, 8.19) resulting in a 1.7% change due to confounding by these comorbidities. CONCLUSION: The disability statuses of the patients with primary LBP in this study were more significantly affected by comorbidities of BMI, depression and smoking than patients with report of LBLP. However, these comorbidities contribute little to the relationship of primary low back related leg pain and Oswestry scores ≥ 40.

Characterization and rate of symptomatic adjacent-segment disease after index lateral lumbar interbody fusion: a single-institution, multisurgeon case series with long-term follow-up.

OBJECTIVE: The rate of symptomatic adjacent-segment disease (ASD) after newer minimally invasive techniques, such as lateral lumbar interbody fusion (LLIF), is not known. This study aimed to assess the incidence of surgically significant ASD in adult patients who have undergone index LLIF and to identify any predictive factors. METHODS: Patients who underwent index LLIF with or without additional posterior pedicle screw fixation between 2010 and 2012 and received a minimum of 2 years of postoperative follow-up were retrospectively included. Demographic and perioperative data were recorded, as well as radiographic data and immediate perioperative complications. The primary endpoint was revision surgery at the level above or below the previous construct, from which a survivorship model of patients with surgically significant symptomatic ASD was created. RESULTS: Sixty-seven patients with a total of 163 interbody levels were included in this analysis. In total, 17 (25.4%) patients developed surgically significant ASD and required additional surgery, with a mean ± SD time to revision of 3.59 ± 2.55 years. The mean annual rate of surgically significant ASD was 3.49% over 7.27 years, which was the average follow-up. One-third of patients developed significant disease within 2 years of index surgery, and 1 patient required surgery at the adjacent level within 1 year. Constructs spanning 3 or fewer interbody levels were significantly associated with increased risk of surgically significant ASD; however, instrument termination at the thoracolumbar junction did not increase this risk. Surgically significant ASD was not impacted by preoperative disc height, foraminal area at the adjacent levels, or changes in global or segmental lumbar lordosis. CONCLUSIONS: The risk of surgically significant ASD after LLIF was similar to the previously reported rates of other minimally invasive spine procedures. Patients with shorter constructs had higher rates of subsequent ASD.

Minimally invasive interbody fusion for revision lumbar surgery: technical feasibility and safety.

STUDY DESIGN: Retrospective chart review of one surgeon's practice. OBJECTIVE: We evaluate the perioperative morbidity of 43 patients undergoing minimally invasive lumbar interbody fusion to differentiate risks between primary and revision surgery candidates. SUMMARY OF BACKGROUND DATA: Minimally invasive approaches to the lumbar spine have rapidly evolved and the technical feasibility and safety of minimally invasive interbody fusion is well established. Revision surgery is technically more challenging and may cause avoidance of such approaches because of altered anatomy and absent bony landmarks. Description of minimally invasive surgery approaches among revision patients and the feasibility of such techniques demands clarification. METHODS: Forty-three consecutive minimally invasive transforaminal lumbar interbody fusions (TLIFs) and posterior lumbar interbody fusions (PLIFs) were reviewed. Estimated blood loss, operative time, and complication rates were compared between primary and revision patients using Student t tests. RESULTS: Seventeen revision surgery cases (40%) were compared with 26 primary surgeries (60%) to elucidate differences in operative time, estimated blood loss, and complications. Demographic variables were similar in both groups. Estimated blood loss trended higher among the PLIF group and among revision cases, though no statistical significance was observed. A higher rate of complications, most notably incidental durotomy, was observed among revision cases in both PLIF and TLIF patients. One patient undergoing primary surgery had an intraoperative pedicle fracture, and 1 patient undergoing revision surgery had an asymptomatic screw malposition. No patients had a major complication, nerve injury, infection, or conversion to an open procedure. CONCLUSIONS: Minimally invasive lumbar interbody fusion by revision surgery is technically feasible and is not associated with more blood loss or neurologic morbidity. However, revision surgery has a higher minor perioperative complication rate, particularly of incidental durotomy. These outcomes demand significant experience before attempting minimally invasive revision surgery in the lumbar spine.

Reliability and diagnostic accuracy of clinical special tests for myelopathy in patients seen for cervical dysfunction.

STUDY DESIGN: Case control study. BACKGROUND: Myelopathy is a clinical diagnosis based largely on initial examination findings during a clinical screen, followed by imaging verification of cord injury or compression. At present, few studies have examined the reliability and diagnostic accuracy of clinical examination measures. OBJECTIVES: To determine the reliability and diagnostic accuracy of neurological tests associated with the diagnosis of myelopathy. METHODS AND MEASURES: Reliability and diagnostic accuracy of 7 frequently used tests and measures and subjective findings associated with myelopathy were examined on consecutive patients with cervical pain. Interrater reliability and diagnostic accuracy values, including posttest probability, based on a pretest probability of 40%, were calculated for each test and for combinations of tests and measures. RESULTS: Four of the 7 diagnostic tests were found to have a substantial interrater reliability. None of the single or clusters of tests yielded low negative likelihood ratios. Of the individual tests, the Babinski sign demonstrated the highest positive likelihood ratio (LR+, 4.0; 95% CI: 1.1-16.6) and posttest probability (73%) for diagnosis, but yielded only a moderate negative likelihood ratio (LR-, 0.7; 95% CI: 0.6-0.9). Combinations of tests did not yield improved accuracy values over single test results. CONCLUSION: This study demonstrated that 4 of 7 tests used to screen for myelopathy offered substantial levels of interrater agreement when used on individuals with cervical dysfunction. None of the tests when performed individually or in combinations are effective for screening; however, the Babinski sign did alter posttest probability more significantly than combinations of test findings. LEVEL OF EVIDENCE: Diagnosis, Level 2b.

Neurological Outcomes After Surgical or Conservative Management of Spontaneous Spinal Epidural Abscesses: A Systematic Review and Meta-Analysis of Data From 1980 Through 2016.

STUDY DESIGN: This is a meta-analysis. OBJECTIVE: Perform a systematic review and quantitative meta-analysis of neurological outcomes from all available spinal epidural abscess (SEA) literature published between 1980 and 2016. SUMMARY OF BACKGROUND DATA: Current literature on SEAs lacks large-scale data characterizing prognostic factors and surgical indications. MATERIALS AND METHODS: PubMed was queried for studies reporting neurological outcomes from patients undergoing conservative or surgical management for spontaneous SEA. Inclusion criteria included outcomes data measured ≥6 months after presentation, ≥10 human subjects, and diagnosis by magnetic resonance imaging or Computed tomography-myelogram. Where available, demographic data, abscess location, comorbidities, pretreatment neurological deficits, treatment methods, bacterial speciation, and complications were extracted from each study. Potential outcome predictors represented by continuous variables were compared using student t test and categorical variables were compared using the Pearson χ test. Variables identified as potentially associated with outcome (P≤0.05) were subjected to meta-analysis using Cochran-Mantel-Haenszel testing to calculate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: In total, 808 patients were analyzed from 20 studies that met inclusion criteria. 456 (56.3%) patients were treated with surgery and antibiotics, and 353 (43.7%) patients were managed with antibiotics alone. Neither surgical intervention (OR=1.01, 95% CI=0.40-2.59), lumbosacral location (OR=1.51, 95% CI=0.23-9.79), nor neurological deficit on presentation (OR=0.88, 95% CI=0.40-1.92) were significantly associated with good (stable or improved) or bad (worsened) neurological outcome, whereas delayed surgery was significantly associated with bad outcome (OR=0.01, 95% CI=0.02-0.62) and cervicothoracic location approached significance for predicting bad outcome (OR=0.41, 95% CI=0.15-1.09). CONCLUSIONS: Current literature does not definitively support or oppose surgical intervention in all SEA cases. Therefore, until better evidence exists, the decision to operate must be made on an individual case-by-case basis with the goals of preventing neurological decline, obtaining source control after failed conservative treatment, or restoring spinal stability.

Impact of preoperative neurological status on perioperative morbidity associated with anterior and posterior cervical fusion.

OBJECT: Cervical spine fusion is performed for various indications in patient populations ranging from young and healthy to aged and frail. Whereas disease pathoanatomy dictates the surgical approach, preoperative neurological status does not necessarily implicate a specific technique. Although one expects anterior decompression to be performed over fewer segments in healthier patients who experience fewer complications and faster recovery, the impact of pre-operative myelopathy on perioperative complications remains unclear. No large-scale study has evaluated rates of common complications for cervical fusion or their association with surgical approach and neurological status. METHODS: Data for 96,773 patients who underwent cervical fusion for degenerative disease between 1988 and 2003 were collected from the Nationwide Inpatient Sample database. Patients were grouped according to surgical approach (anterior versus posterior) and preoperative neurological status (myelopathic versus nonmyelopathic). Multivariate regression was used to evaluate group effects on selected postoperative complications, length of stay, and disposition at the time of hospital discharge. Although this technique can control for the observed covariates, the absence of key information such as the number of fused levels precludes statistical comparison between patients who underwent anterior or posterior approaches. RESULTS: In this study the authors confirmed that preoperative neurological status impacts perioperative morbidity. For example, patients who were nonmyelopathic and underwent an anterior approach were 7 years younger than the rest of the cohort, and they had a mortality rate of 0.05%. Transfusion was required in 0.34%, and venous thromboembolism occurred in 0.04%. Conversely, these rates were > 13-fold higher in patients with myelopathy who underwent a posterior approach. Furthermore, independent of approach, preoperative myelopathy is highly prognostic of death, pneumonia, transfusion, infection, length of stay, and posthospital disposition. These outcomes at least doubled, with some increasing > 10-fold. CONCLUSIONS: This nationwide study clarifies the frequency and associations of inpatient complications encountered when treating cervical spine disease. Whereas immediate complications due to anterior approaches are limited, patients with myelopathy who undergo a posterior approach have a more sobering outlook. This study shows that clinical myelopathy augments rates of complication during cervical fusion, regardless of the approach. The exclusion of pathoanatomical data from the Nationwide Inpatient Sample database, of key importance in guiding the surgical approach, prevents any conclusions being drawn about the merits and disadvantages of anterior versus posterior surgery.

Feasibility of Endoscopic Inspection of Pedicle Wall Integrity in a Live Surgery Model.

BACKGROUND: Perforations of the pedicle wall during cannulation can occur with experienced surgeons. Direct endoscopic visualization has not been used to inspect pedicles previously due to bone bleeding obscuring the camera visualization. The hypothesis of this study was that endoscopic visualization of pedicle wall integrity was technically feasible and would enable identification of clinically significant pedicle breaches. METHODS: A live porcine model was used. Eight lumbar pedicles were cannulated. Clinically significant breaches were created. An endoscope was introduced and was used to inspect the pedicles. RESULTS: All lumbar pedicles were endoscopically visible at a systolic pressure of 100 mm Hg. Clinically relevant anatomic structures and iatrogenic pathology, such as medial, lateral, and anterior breaches, were identified. There were no untoward events resulting from endoscopic inspection of the pedicle endosteal canal. CONCLUSIONS: Endoscopic inspection of lumbar pedicles was safe and effective. The findings on endoscopic inspection corresponded with the ball-tip probe palpation techniques. Additional techniques, such as selection between 2 tracts, was possible with the endoscopic technique.

Minimally Invasive Lateral Access Surgery and Reoperation Rates: A Multi-Institution Retrospective Review of 2060 Patients.

BACKGROUND: Risk factors for surgical revision remain important because of additional readmission, anesthesia, and morbidity for the patient and significant cost for health care systems. Although the rate of reoperation (RRO) is well described for traditional open posterior (OP) approaches, the RRO in minimally invasive lateral (MIL) surgery remains poorly characterized. This study compares the RRO in patients undergoing decompressive lumbar spine surgery via MIL versus OP approaches. METHODS: Patient demographics and comorbidities were retrospectively collected for 2060 patients undergoing single-stage elective lumbar spinal surgery at multiple institutions. A subset of 1484 patients had long-term data (long-term cohort [LT cohort]). The RRO was compared between approaches through univariate and multivariate analysis. RESULTS: There were 1292 patients (62.7%) who underwent lateral access surgery, whereas 768 patients (37.3%) underwent OP surgery. The MIL cohort was significantly older, had a higher proportion of men, and had more comorbidities than the OP cohort. In the LT cohort, lateral patients were significantly older and had more comorbidities, with a lower body mass index and a lower proportion of men and smokers. Surgical complications between the groups trended to be similar. The MIL cohort had a significantly lower RRO at both 30 days (approximately 57% lower, MIL cohort: 1.01% vs. OP cohort: 2.36%, P = 0.02) and 2 years (approximately 61% lower, MIL cohort: 2.09% vs. OP cohort: 5.37%, P < 0.01) after surgery. On multivariate analysis, surgical approach was the only significant predictor for the RRO at both 30 days (open posterior approach odds ratio [OR], 4.47; 95% confidence interval [CI], 1.33-15.09; P = 0.02) and 2 years (open posterior approach OR, 3.26; 95% CI, 1.26-8.42; P = 0.01). CONCLUSIONS: This study shows that MIL surgical approaches, compared with OP approaches, have a significantly lower RRO after lumbar spine surgery.