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OBJECTIVE Extension fractures in the setting of diffuse idiopathic skeletal hyperostosis (DISH) represent highly unstable injuries. As a result, these fractures are most frequently treated with immediate surgical fixation to limit any potential risk of associated neurological injury. Although this represents the standard of care, patients with significant comorbidities, advanced age, or medical instability may not be surgical candidates. In this paper, the authors evaluated a series of patients with extension DISH fractures who were treated with orthosis alone and evaluated their outcomes. METHODS A retrospective review from 2015 to 2022 was conducted at a large level 1 trauma center. Patients with extension-type DISH fractures without neurological deficits were identified. All patients were treated conservatively with orthosis alone. Baseline patient characteristics and adverse outcomes are reported. RESULTS Twenty-seven patients were identified as presenting with extension fractures associated with DISH without neurological deficit. Of these, 22 patients had complete follow-up on final chart review. Of these 22 patients, 21 (95.5%) were treated successfully with external orthosis. One patient (4.5%) who was noncompliant with the brace had an acute spinal cord injury 1 month after presentation, requiring immediate surgical fixation and decompression. No other complications, including skin breakdown or pressure ulcers related to bracing, were reported. CONCLUSIONS Treatment of extension-type DISH fractures may be a reasonable option for patients who are not candidates for safe surgical intervention; however, a risk of neurological injury secondary to delayed instability remains, particularly if patients are noncompliant with the bracing regimen. This risk should be balanced against the high complication rate and potential mortality associated with surgical intervention in this patient population.

OBJECTIVE Lumbar synovial cysts (LSCs) represent a relatively rare clinical pathology that may result in radiculopathy or neurogenic claudication. Because of the potential for recurrence of these cysts, some authors advocate for segmental fusion, as opposed to decompression alone, as a way to eliminate the risk for recurrence. The objective of this study was to create a predictive score for synovial cyst recurrence following decompression without fusion. METHODS A retrospective chart review was completed of all patients evaluated at a single center over 20 years who were found to have symptomatic LSCs requiring intervention. Only patients undergoing decompression without fusion were included in the analysis. Following this review, baseline characteristics were obtained as well as radiological information. A machine learning method (risk-calibrated supersparse linear integer model) was then used to create a risk stratification score to identify patients at high risk for symptomatic cyst recurrence requiring repeat surgical intervention. Following the creation of this model, a fivefold cross-validation was completed. RESULTS In total, 89 patients were identified who had complete radiological information. Of these 89 patients, 11 developed cyst recurrence requiring reoperation. The Lumbar Synovial Cyst Score was then created with an area under the curve of 0.83 and calibration error of 11.0%. Factors predictive of recurrence were found to include facet inclination angle > 45°, canal stenosis > 50%, T2 joint space hyperintensity, and presence of grade I spondylolisthesis. The probability of cyst recurrence ranged from < 5% for a score of 2 or less to > 88% for a score of 7. CONCLUSIONS The Lumbar Synovial Cyst Score model is a quick and accurate tool to assist in clinical decision-making in the treatment of LSCs.

Multiple sclerosis (MS) is an autoimmune inflammatory disease that results in demyelination of the central nervous system (CNS). MS affects as many as 350,000 individuals in the United States and commonly presents before the age of 45 years. Patients with MS, as the general population, are likely to encounter degenerative changes of the spine as they age, and this can pose a unique challenge to both patients with MS and physicians, as both conditions can have a great deal of symptomatic overlap despite stark differences in management. Currently there is no definitive approach that allows physicians to distinguish between the 2 conditions; however, specific clinical and radiologic findings have been identified as being useful in evaluating these patients.

BACKGROUND CONTEXT Outcomes of treatment in care of patients with spinal disorders are directly related to patient selection and treatment indications. However, for many disorders, there is absence of consensus for precise indications. With the increasing emphasis on quality and value in spine care, it is essential that treatment recommendations and decisions are optimized. PURPOSE The purpose of the North American Spine Society Appropriate Use Criteria was to determine the appropriate (ie reasonable) multidisciplinary treatment recommendations for patients with degenerative spondylolisthesis across a spectrum of more common clinical scenarios. STUDY DESIGN A Modified Delphi process was used. METHODS The methodology was based on the Appropriate Use Criteria development process established by the Research AND Development Corporation. The topic of degenerative spondylolisthesis was selected by the committee, key modifiers determined, and consensus reached on standard definitions. A literature search and evidence analysis were completed by one work group simultaneously as scenarios were written, reviewed, and finalized by another work group. A separate multidisciplinary rating group was assembled. Based on the literature, provider experience, and group discussion, each scenario was scored on a nine-point scale on two separate occasions, once without discussion and then a second time following discussion based on the initial responses. The median rating for each scenario was then used to determine if indications were rarely appropriate (1 – 3), uncertain (4-6), or appropriate (7-9). Consensus was not mandatory. RESULTS There were 131 discrete scenarios. These addressed questions on bone grafting, imaging, mechanical instability, radiculopathy with or without neurological deficits, obesity, and yellow flags consisting of psychosocial and medical comorbidities. For most of these, appropriateness was established for physical therapy, injections, and various forms of surgical intervention. The diagnosis of spondylolisthesis should be determined by an upright x-ray. Scenarios pertaining to bone grafting suggested that patients should quit smoking prior to surgery, and that use of BMP should be reserved for patients who had risk factors for non-union. Across all clinical scenarios, physical therapy (PT) had an adjusted mean of 7.66, epidural steroid injections 5.76, and surgery 4.52. Physical therapy was appropriate in most scenarios, and most appropriate in patients with back pain and no neurological deficits. Epidural steroid injections were most appropriate in patients with radiculopathy. Surgery was generally more appropriate for patients with neurological deficits, higher disability scores, and dynamic spondylolisthesis. Mechanical back pain and presence of yellow flags tended to be less appropriate, and obesity in general had relatively little influence on decision making. Decompression alone was more strongly considered in the presence of static versus dynamic spondylolisthesis. On average, posterior fusion with or without interbody fusion was similarly appropriate, and generally more appropriate than stand-alone interbody fusion which was in turn more appropriate than interspinous spacers. CONCLUSIONS Multidisciplinary appropriate treatment criteria were generated based on the Research AND Development methodology. While there were consistent and significant differences between surgeons and non-surgeons, these differences were generally very small. This document provides comprehensive evidence-based recommendations for evaluation and treatment of degenerative spondylolisthesis. The document in its entirety will be found on the North American Spine Society website ( https://www.spine.org/Research-Clinical-Care/Quality-Improvement/Appropriate-Use-Criteria) .

Spinal fusion is frequently performed for a variety of indications. It is performed to treat instability due to trauma, infection, or neoplasm. It may be used to treat regional or global spinal deformity. There are even occasions when it is appropriate as a treatment of low back pain without overt instability or deformity. One common indication for fusion is as an adjunct to decompression for patients with neurogenic claudication or radiculopathy caused by stenosis associated with spondylolisthesis. There have been a number of high-quality publications in high-quality journals that have reported conflicting results regarding the utility of fusion in this patient population. The existence of conflicting data from seemingly similarly designed trials has resulted in some confusion as to when a fusion should be used. This chapter will describe the controversy, discuss the likely basis for the disparate results reported in the literature, and recommend a reasonable treatment strategy. Going forward, the SLIP II study is an ongoing randomized, controlled trial designed to help clarify the situation. Preliminary findings drawn from this study will be discussed.

Background context The North American Spine Society's (NASS) Evidence Based Clinical Guideline for the Diagnosis and Treatment of Low Back Pain features evidence-based recommendations for diagnosing and treating adult patients with nonspecific low back pain. The guideline is intended to reflect contemporary treatment concepts for nonspecific low back pain as reflected in the highest quality clinical literature available on this subject as of February 2016. PURPOSE The purpose of the guideline is to provide an evidence-based educational tool to assist spine specialists when making clinical decisions for adult patients with nonspecific low back pain. This article provides a brief summary of the evidence-based guideline recommendations for diagnosing and treating patients with this condition. Study design This is a guideline summary review. Methods This guideline is the product of the Low Back Pain Work Group of NASS’ Evidence-Based Clinical Guideline Development Committee. The methods used to develop this guideline are detailed in the complete guideline and technical report available on the NASS website. In brief, a multidisciplinary work group of spine care specialists convened to identify clinical questions to address in the guideline. The literature search strategy was developed in consultation with medical librarians. Upon completion of the systematic literature search, evidence relevant to the clinical questions posed in the guideline was reviewed. Work group members utilized NASS evidentiary table templates to summarize study conclusions, identify study strengths and weaknesses, and assign levels of evidence. Work group members participated in webcasts and in-person recommendation meetings to update and formulate evidence-based recommendations and incorporate expert opinion when necessary. The draft guideline was submitted to an internal and external peer review process and ultimately approved by the NASS Board of Directors. Results Eighty-two clinical questions were addressed, and the answers are summarized in this article. The respective recommendations were graded according to the levels of evidence of the supporting literature. Conclusions The evidence-based clinical guideline has been created using techniques of evidence-based medicine and best available evidence to aid practitioners in the diagnosis and treatment of adult patients with nonspecific low back pain. The entire guideline document, including the evidentiary tables, literature search parameters, literature attrition flowchart, suggestions for future research, and all of the references, is available electronically on the NASS website at https://www.spine.org/ResearchClinicalCare/QualityImprovement/ClinicalGuidelines.aspx

Background We have been using computed tomography (CT) guidance for percutaneous glycerol rhizotomy (PGR) for the last 7 years. As a quality improvement exercise, we recently began using general anesthesia (GA) with the use of a laryngeal mask airway (LMA) because of our perception that the procedure went faster and that there was less radiation exposure because of less patient movement. We aim to compare PGR radiation exposure and procedural time between patients receiving local anesthetic with sedation and those receiving GA/LMA. Methods A single-center historical cohort study was performed using patients treated with PGR between 2017 and 2019. Ninety-two surgeries were conducted during the study period: 64 surgeries had local anesthetic with intravenous sedation, and 28 surgeries had deeper anesthetic with LMA. Data analyzed included the number of CT sequences obtained, needle placement time, and total radiation dose. Results Use of GA/LMA resulted in a 23% decrease in mean radiation dose (565.5 vs. 436.1 μGy × cm, P = 0.014), number of CT sequences required (7.4 vs. 5.7, P = 0.003), and needle placement time (12.8 vs. 9.8 minutes, P = 0.006). Additionally, 10 patients underwent multiple glycerol rhizotomies during the collection period with both anesthetic types being used at least once. Seven of 10 patients (70.0%) had a reduction in total radiation dose, number of CT sequences obtained, and needle placement time when GA/LMA was used. There were no procedure- or anesthetic-related complications in this patient cohort. Conclusions The use of GA/LMA during PGR is associated with decreased radiation exposure without increased anesthetic complications.

BACKGROUND Noonan syndrome (NS) is a rare genetic RASopathy with multisystem implications. The disorder is typically characterized by short stature, distinctive facial features, intellectual disability, developmental delay, chest deformity, and congenital heart disease. NS may be inherited or arise secondary to spontaneous mutations of genes in the Ras/mitogen activated protein kinase signaling pathways. OBSERVATIONS Numerous case reports exist detailing the association between NS and Chiari I malformation (CM-I), although this relationship has not been fully established. Patients with NS who present with CM-I requiring operation have shown high rates reoperation for failed decompression. The authors reported two patients with NS, CM-I, and syringomyelia who had prior posterior fossa decompressions without syrinx improvement. Both patients received reoperation with successful outcomes. LESSONS The authors highlighted the association between NS and CM-I and raised awareness that patients with these disorders may be at higher risk for failed posterior fossa decompression, necessitating reoperation.

Background The presence of symptomatic lumbar facet cysts has been associated with segmental instability. Given this association, decompression versus decompression with fusion is a frequently debated topic. Multiple grading scales have been devised to identify patients at high risk for development of cyst recurrence; however, there exists no external evaluation of these scales. Methods A retrospective review of 54 patients undergoing initial treatment for lumbar synovial cysts at a single institution over the past 12 years was conducted. Surgical treatment consisted of decompression with cystectomy without fusion. Patients were assessed and classified according to the NeuroSpine Surgery Research Group (NSURG) and Rosenstock Classification systems. Five neurosurgeons reviewed the preoperative magnetic resonance images, and results were classified. Interrater reliability was assessed using both Gwet’s AC1 coefficient and Krippendorff’s alpha. A 1-way analysis of variance was used to evaluate predictive ability of both classification systems. Results In total, of the 54 patients who underwent decompression, 7 had cyst recurrence. Overall cyst recurrence was most common in NSURG grade 2 cysts (3/12, 25%) followed by grade 1 cysts (4/27, 14.8%). Of the NSURG grade 3 and 4 patients, none had cyst recurrence. In the Rosenstock grades the most common recurrence was in grade 3 cysts (1/4, 25%) followed by grade 1 cysts (5/26, 19.2%). Interrater reliability demonstrated good reproducibility on Gwet’s AC1 and Krippendorff’s alpha on both grading scales. Neither score was predictive of cyst recurrence (P > 0.05). Conclusions The Rosenstock and NeuroSpine scores demonstrate good overall interrater reliability but are inconsistent in their ability to predict recurrence of lumbar facet cysts.

High quality evidence is difficult to generate, leaving substantial knowledge gaps in the treatment of spinal conditions. Appropriate use criteria (AUC) are a means of determining appropriate recommendations when high quality evidence is lacking.Define appropriate use criteria (AUC) of cervical fusion for treatment of degenerative conditions of the cervical spine.Appropriate use criteria for cervical fusion were developed using the RAND/UCLA appropriateness methodology. Following development of clinical guidelines and scenario writing, a one-day workshop was held with a multidisciplinary group of 14 raters, all considered thought leaders in their respective fields, to determine final ratings for cervical fusion appropriateness for various clinical situations.Final rating for cervical fusion recommendation as either "Appropriate," "Uncertain" or "Rarely Appropriate" based on the median final rating among the raters.Inclusion criteria for scenarios included patients aged 18 to 80 with degenerative conditions of the cervical spine. Key modifiers were defined and combined to develop a matrix of clinical scenarios. The median score among the raters was used to determine the final rating for each scenario. The final rating was compared between modifier levels. Spearman's rank correlation between each modifier and the final rating was determined. A multivariable ordinal regression model was fit to determine the adjusted odds of an "Appropriate" final rating while adjusting for radiographic diagnosis, number of levels and symptom type. Three decision trees were developed using decision tree classification models and variable importance for each tree was computed.Of the 263 scenarios, 47 (17.9 %) were rated as rarely appropriate, 66 (25%) as uncertain and 150 (57%) were rated as appropriate. Symptom type was the modifier most strongly correlated with the final rating (adjusted ρ2 = 0.58, p.01). A multivariable ordinal regression adjusting for symptom type, diagnosis, and number of levels and showed high discriminative ability (C statistic = 0.90) and the adjusted odds ratio (aOR) of receiving a final rating of "Appropriate" was highest for myelopathy (aOR, 7.1) and radiculopathy (aOR, 4.8). Three decision tree models showed that symptom type and radiographic diagnosis had the highest variable importance.Appropriate use criteria for cervical fusion in the setting of cervical degenerative disorders were developed. Symptom type was most strongly correlated with final rating. Myelopathy or radiculopathy were most strongly associated with an "Appropriate" rating, while axial pain without stenosis was most associated with "Rarely Appropriate."

Background Treatment of spinal cord injury (SCI) induced neuropathic pain (NP) proves to be extremely clinically challenging as the mechanism behind SCINP is poorly understood. Matrix metalloproteinase (MMP) is largely responsible for the early disruption of the blood spinal cord barrier. This system initiates macrophage infiltration and degradation of myelin, which plays a pivotal role in how NP occurs. In a recent study, we demonstrated that folic acid (FA) treatment to cSCI rats reduced NP and improved functional recovery by repressing MMP-2 expression. We hypothesize that MMP-2 expression is suppressed because FA actively methylates the DNA sequence that encodes for the MMP-2 protein. However, modulation of MMP-2 expression for alleviation of NP is only pertinent to the mid- to late-phase of injury. Therefore, we need to explore alternate therapeutic methods to target the early- to mid-phase of injury to wholly alleviate NP. Purpose Furthering our previous findings on inhibiting MMP-2 expression by FA in mid- and late- phase following cSCI in rats, we hypothesized that FA will methylate and suppress MMP-9 expression during the early- phase, day 1, 3, 7 post cSCI and mid- phase (day 18 post cSCI), in comparison with MMP-2 expression during mid- and the late-phase of cSCI. Methods Adult male Sprague Dawley rats (250-270g) underwent cSCI, using a NYU impactor, with 12.5 gm/cm injury. The spinal cord-injured animals were treated intraperitoneally (i.p.) with a standardized dose of FA (80 μg/kg body weight) on day 1, 2, 3, prior to cSCI, followed by daily injection up to 14 or 17 days post-cSCI in different experiments. Animals were euthanized on day 1, 3, 7 post cSCI (early- phase), day 18 post cSCI (mid- phase), and day 42 post cSCI (late-phase) and the epicenter region of injured spinal cord were harvested for MMP-9 and MMP-2 expression analysis by Western blots technique. Results i) During early-phase on day 1, 3, and 7, the quantitation displayed no statistical significance in MMP-9 expression, between water- and FA- injected rats. ii) On day 18 post-cSCI, FA significantly modulates the expression of MMP-9 (p = 0.043) iii) Comparing results with MMP-2 expression and inhibition, FA significantly modulates the expression of MMP-2 on day 18 post cSCI (FA- and water-injected rats (p = 0.003). iv) In addition, FA significantly modulates the expression of MMP-2 on day 42 post-cSCI comparing FA- and water- injected rat groups (p = 0.034). Conclusion We report that FA administration results in alleviating cSCI-induced NP by inhibiting MMP-9 in the proposed mid- phase of cSCI. However, FA administration resulted in MMP-2 decline during both mid- through late- phase following cSCI. Our study elucidates a new phase of cSCI, the mid-phase. We conclude that further investigation on discovering and quantifying the nature of the mid- phase of SCI injury is needed.

Background The management of lumbar synovial cysts (LSC) has been a controversial topic for many years. Whereas many authors label LSC as markers of instability and thus necessitating fusion, others suggest that decompression alone without fusion is a viable initial treatment option. Our objective was to clarify outcomes in patients undergoing decompression alone and decompression with fusion for symptomatic LSC and identify factors for cyst recurrence. Methods A retrospective case series was performed of all patients undergoing initial treatment for LSC at a single institution ranging from January 1999 to February 2020. Surgical treatment included either decompression with cystectomy or decompression with cystectomy and a fusion procedure. Preoperative symptoms were collected and included radicular pain, motor deficits, sensory deficits, or bowel/bladder changes. Radiographic data were calculated individually and confirmed with radiology reports. Categorical variables were assessed using χ2 analysis and continuous variables were assessed with the 2-sample t test. Results In total, 161 patients were identified as presenting with symptomatic LSC. Of these, 104 patients underwent decompression alone versus 57 who underwent decompression and fusion. In the decompression group 11 patients required reoperation at the level of the cyst compared with none in those undergoing fusion as their initial procedure (10.5% vs. 0%, P = 0.012). On subgroup analysis of those undergoing decompression as their initial procedure, patients with cyst recurrence demonstrated a statistically significant greater coronal facet inclination angle compared with those without cyst recurrence (52.4° vs. 40.6°, P = 0.02). Conclusions Decompression alone is a reasonable choice for the initial management of LSC, although it does carry a significant risk of same-level reoperation due to cyst recurrence and spondylolisthesis. Preoperative coronal facet inclination angle may be a useful measurement in predicting cyst recurrence following decompression.

The American Board of Neurological Surgery (ABNS) was incorporated in 1940 in recognition of the need for detailed training in and special qualifications for the practice of neurological surgery and for self-regulation of quality and safety in the field. The ABNS believes it is the duty of neurosurgeons to place a patient’s welfare and rights above all other considerations and to provide care with compassion, respect for human dignity, honesty, and integrity. At its inception, the ABNS was the 13th member board of the American Board of Medical Specialties (ABMS), which itself was founded in 1933. Today, the ABNS is one of the 24 member boards of the ABMS.To better serve public health and safety in a rapidly changing healthcare environment, the ABNS continues to evolve in order to elevate standards for the practice of neurological surgery. In connection with its activities, including initial certification, recognition of focused practice, and continuous certification, the ABNS actively seeks and incorporates input from the public and the physicians it serves. The ABNS board certification processes are designed to evaluate both real-life subspecialty neurosurgical practice and overall neurosurgical knowledge, since most neurosurgeons provide call coverage for hospitals and thus must be competent to care for the full spectrum of neurosurgery.The purpose of this report is to describe the history, current state, and anticipated future direction of ABNS certification in the US.

Background Context Despite well done randomized clinical trials, the role of fusion as an adjunct to decompression for the treatment of patients with degenerative spondylolisthesis remains controversial. There is substantial variation in the use of fusion as well as the techniques used for fusion for a population of patients all described by a single ICD10 code. Purpose We sought to investigate the source of the variation in the perceived role of fusion by looking at surgeon as well as patient specific factors. Study Design Prospective cohort study examining the variability of recommendations from an expert panel of surgeons based imaging and clinical vignettes. Patient Sample Patients with degenerative spondylolisthesis and stenosis Outcome Measures A six-category treatment schema based on level of invasiveness of proposed surgeries with one through three representing non-fusion strategies and categories four through six representing fusion strategies. Methods The authors are conducting the ongoing spinal laminectomy versus instrumented pedicle screw (SLIP) II study in which patients with grade one degenerative spondylolisthesis and stenosis are randomized to two groups: a review group in which patients are treated as per recommendations of an expert panel and a non-review group in which patients are treated as per the referring surgeon's preference. In the former (review group), clinical vignettes and radiographic studies were evaluated by an expert panel of spine surgeons. The panel then provided these recommendations to the referring surgeon. We investigated the underlying variability by looking both at the number of similar or different recommendations received by an individual patient (surgeon related variability) as well as the number of similar or different recommendations offered by individual surgeons across the population of patients (patient heterogeneity). Agreement between surgeons for fusion versus non-fusion (Categories 1-3 versus 4-6) was calculated using a Kappa value from a mixed effects logistic regression model. We looked at Kappa for agreement and weighted Kappa for association of ratings on the ordinal 1-6 scale with a mixed effects linear regression model. Additionally, we analyzed the summary of data between patients after averaging the rater scores within patients. Similarly, we summarized the data between surgeons after averaging their scores over the patients that each surgeon reviewed. Results One hundred and fourteen patients received 1463 treatment recommendations. On average, fusion was recommended 58.5% of the time. Overall agreement was low, and perfect agreement on the need for fusion was seen in only 24 (21.1%) of patients. Kappa statistic for agreement on fusion was 0.378 (95% CI 0.324 to 0.432). The average score across surgeons was 4.2 (0.6) with a range of 3 to 5.3. The most common single recommendation was for fusion with interbody fusion (40.8%) and the lowest was for decompression with non-instrumented fusion (0.5%). Conclusions We demonstrated variability in surgical approach when individual patients were evaluated by a panel of surgeons indicating that even "expert" surgeons disagree with each other regarding the need for fusion in individual patients. We were also able to demonstrate that individual patients received consistent recommendations that were very different from those received by other individuals evaluated by the same surgeons. This indicates that there is patient-related heterogeneity driving variability independent of surgeon factors.

Background/Aims Spine and spinal cord pathologies and associated neuropathic pain are among the most complex medical disorders to treat. While rodent models are widely used in spine and spinal cord research and have provided valuable insight into pathophysiological mechanisms, these models offer limited translatability. Thus, studies in rodent models have not led to the development of clinically effective therapies. More recently, swine has become a favored model for spine research because of the high congruency of the species to humans with respect to spine and spinal cord anatomy, vasculature, and immune responses. However, conventional breeds of swine commonly used in these studies present practical and translational hurdles due to their rapid growth toward weights well above those of humans. Methods In the current study, we evaluated the suitability of a human-sized breed of swine developed at the University of Wisconsin-Madison, the Wisconsin Miniature SwineTM (WMSTM), in the context of thoracic spine morphometry for use in research to overcome limitations of conventional swine breeds. The morphometry of thoracic vertebrae (T1-T15) of 5-6 months-old WMS was analyzed and compared to published values of human and conventional swine spines. Results The key finding of this study is that WMS spine more closely models the human spine for many of the measured vertebrae parameters, while being similar to conventional swine in respect to the other parameters. Conclusion WMS provides an improvement over conventional swine for use in translational spinal cord injury studies, particularly long-term ones, because of its slower rate of growth and its maximum growth being limited to human weight and size.

Spinal cord injury (SCI) is a physically and psychologically devastating clinical condition. The typical treatment regimens of decompressive surgery and rehabilitation therapy still leave many patients with permanent disability. The development of new therapies and devices can be accelerated if relevant translational animal models are more effectively used in pre-clinical stages. Swine is a highly relevant model for SCI research, especially with respect to spine and spinal cord anatomy, spine vasculature, immune responses to injury, and functional assessments. Several spine injury models have recently been developed for swine and are beginning to be used to evaluate new therapies. Swine models of SCI offer tremendous advantages for efficient translation of pre-clinical discoveries and the development of new therapies and devices. Future swine models will also be enhanced by advances in gene-editing technology to further elucidate the complex pathophysiology associated with SCI and provide a means to engineer specific spinal pathologies.

BACKGROUND Percutaneous glycerol rhizotomy (PGR) is a well-described treatment for trigeminal neuralgia; however, the technique in using surface landmarks and fluoroscopy has not drastically changed since being first introduced. In this paper, we describe a protocol for PGR using computed tomography (CT) guidance based on an experience of over 7 yr and 200 patients. OBJECTIVE To introduce an approach for PGR using CT guidance and, in doing so, demonstrate possible benefits over the traditional fluoroscopic technique. METHODS Using a standard CT scanner, patients are placed supine with head in extension. Barium paste and a CT scout image are used to identify and plan a trajectory to the foramen ovale. A laser localization system built into the CT scanner helps to guide placement of the spinal needle into the foramen ovale. The needle position in the foramen is confirmed with a short-sequence CT scan. RESULTS CT-guided PGR provides multiple benefits over standard fluoroscopy, including improved visualization of the skull base and significant reduction in radiation exposure to the surgeon and staff. Side benefits include improved procedure efficiency, definitive imaging evidence of correct needle placement, and potentially increased patient safety. We have had no significant complications in over 200 patients. CONCLUSION CT-guided PGR is a useful technique for treating trigeminal neuralgia based on better imaging of the skull base, better efficiency of the procedure, and elimination of radiation exposure for the surgeon and staff compared to traditional fluoroscopic based techniques.

Fundamentals Historical Background of Minimally Invasive Spine Surgery Michael A. Leonard, Dino Samartzis, Mick J. Perez-Cruet Anatomy of the Spine: An Overview Joshua E. Medow, Daniel K. Resnick Biomechanical Role of the Osseous, Ligamentous, and Muscular Structures of the Spine Rick Placide, Edward C. Benzel Degenerative Disc Disease and Discogenic Pain Charles D. Ray Rationale for Minimally Invasive Spine Surgery Larry T. Khoo Clinical Outcome Analyses Dino Samartzis, Devanand A. Dominique, Mick J. Perez-Cruet, Michael G. Fehlings Complications of Minimally Invasive Spine Procedures Mick J. Perez-Cruet, Noel I. Perin Informed Consent for Minimally Invasive Spine Surgery Harold D. Portnoy Establishing a Minimally Invasive Spine Center Richard N. W. Wohns, Karen L. Saban, Amelia Malick, Faith Berinti, Mick J. Perez-Cruet Image Guidance, Monitoring, and Nonsurgical Techniques Applications of Image Guidance in Minimally Invasive Spine Surgery Kurt M. Eichholz, Sunanda Nioguy, Dino Samartzis, Ron von Jako, Mick J. Perez-Cruet Intraoperative Monitoring During Spine Surgery Steven M. Zak, Blair Calancie, Satish Krishnamurthy Electrophysiologic Monitoring of Percutaneous Pedicle Screw Placement Sylvain Palmer Injection-Based Spine Procedures Lawrence W. Frank, Emil S. Cheng, Howard W. Robinson, Brian A. Couri Stereotactic Radiosurgery for Tumors of the Spine Deborah L. Benzil, Chitti R. Moorthy Surgical Techniques Cervical Spine Microendoscopic Cervical Foraminotomy and Discectomy Faheem A. Sandhu, Mick J. Perez-Cruet, Richard G. Fessler Microendoscopic Cervical Laminectomy Mick J. Perez-Cruet, Dino Samartzis, Richard G. Fessler Anterior Cervical Foraminotomy J. Patrick Johnson, Dino Samartzis, Mick J. Perez-Cruet Microendoscopic Anterior Cervical Discectomy and Fusion Luiz Pimenta, Mick J. Perez-Cruet, Manuel Da Silva Martins, Federico Figueredo Endoscopic Posterior Fixation of the Middle and Lower Cervical Spine Larry T. Khoo, Tooraj Gravori Artificial Cervical Disc Replacement Jan Goffin, Vincent Bryan Thoracic Spine Minimally Invasive Implantation of Epidural Spinal Cord Stimulation Electrodes Matthew R. Johnson, Joanna Swartzbaugh, Daniel J. Tomes, Lyal G. Leibrock Microendoscopic Thoracic Discectomy Mick J. Perez-Cruet, Dino Samartzis, Richard G. Fessler Anterior Thoracoscopic Sympathectomy Curtis A. Dickman Thoracoscopic Discectomy: Lessons Learned and Avoidance of Complications Hyun-Chul Shin, Jonathan Lesser, Robert E. Isaacs, Noel I. Perin Anterior Thoracoscopic Vertebral Reconstruction and Instrumentation Daniel H. Kim, Raju S. V. Balabhadra, Michael Potulski, Rudolf W. Beisse Anterior Thoracoscopic Instrumentation Correction and Fusion for the Treatment of Scoliosis George D. Picetti III Thoracic and Lumbar Vertebroplasty Michael A. Leonard, Mick J. Perez-Cruet Percutaneous Kyphoplasty Sepehr Sani, Richard D. Fessler, Mick J. Perez-Cruet Lumbar Spine Microendoscopic Lumbar Discectomy Mick J. Perez-Cruet, James R. Bean, Richard G. Fessler Microendoscopic Far-Lateral Lumbar Discectomy Kevin T. Foley, Sanjay Gupta, Mick J. Perez-Cruet Endoscopic Lumbar Laminectomy for Stenosis Ronnie I. Mimran, Mick J. Perez-Cruet, Richard G. Fessler, R. Patrick Jacob Percutaneous Pedicle Screw Placement for Spinal Instrumentation Mick J. Perez-Cruet CD Horizon Sextant Percutaneous Pedicle Screw System Eric S. Wieser, Mick J. Perez-Cruet, Larry T. Khoo Percutaneous Pedicle Screw Fixation of the Lumbar Spine Using the PathFinder System Randall R. McCafferty, Larry T. Khoo, Mick J. Perez-Cruet Aperture System: An Approach to Lumbar Arthrodesis and Instrumentation Stephen L. Ritland Posterior Lumbar Instrumentation Using the Atavi System Mick J. Perez-Cruet, Adam M. Shuster eXtreme Lateral Interbody Fusion Luiz Pimenta, Thomas Dan Schaffa, Manuel Da Silva Martins, Federico Figueredo, Roberto Diaz Percutaneous Axial Lumbar Spine Surgery Allen L. Carl, Eric H. Ledet, Carlos Oliviera, Luiz Pimenta, Roberto Diaz Orduz, Andrew H. Cragg Far-Lateral Lumbar Interbody Techniques Paul M. Tsou Mini-Open Anterior Lumbar Interbody Fusion Todd Y. Nida, Sunanda Nioguy, Hormoz Sheikh, Mustafa A. Hares, Mick J. Perez-Cruet Laparoscopic Fusion of the Lumbosacral Spine Stephen E. Heim, Anthony F. Altimari, John L. Andreshak Lumbar Disc Replacement: The Artificial Disc Fred H. Geisler Lumbar Artificial Disc Nucleus Replacement Anthony T. Yeung Percutaneous Osteobiologic Vertebral Reconstruction Sunanda Nioguy, Elizabeth M. H. Kim, Fred H. Geisler, Hormoz Sheikh, Mick J. Perez-Cruet

Unintended durotomies and cerebrospinal fluid leaks are a known complication of spine surgery with an incidence of 0.3% to 35% reported in the literature. Unintended durotomies may be complicated by postural headaches, pseudomeningoceles, meningitis, nerve rootlet entrapment, arachnoiditis, or postoperative wound dehiscence and infections. Older age, severe spinal stenosis, revision surgery, and synovial cysts are some of the risk factors for unintended durotomies. The overall reported incidence of unintended durotomies for all spine surgery is 3.1% with retrospective series reporting a 1% incidence for cervical surgeries, 7.6% incidence for index lumbar surgeries, and incidence for revision lumbar surgeries ranging from 8.1% to 15.9%. As in the thoracic spine, ossified posterior longitudinal ligament (OPLL) is the biggest risk factor for dural tears in the cervical spine, and patients with OPLL are 13.7 times more likely to have a durotomy than patients without OPLL. Direct primary suture repair is a widely accepted option for durotomies with the goal of obtaining a closure that is strong enough to withstand the intrathecal pressure during Valsalva maneuvers while the defect heals. The use of bedrest in the management after unintended durotomy continues to evolve and varies from no bedrest to a short period of bedrest of 24 to 48 hours. There is a trend of no bedrest with early mobilization if the durotomy is completely closed.

Vertebral body compression fractures are ubiquitous and a source of severe pain for many patients. Conservative treatment including bracing and physical therapy is effective for most patients. However patients with a non-healing vertebral body fracture and significant pain lasting >6 weeks but

Over the last several decades, there has been an increased focus on value-based healthcare. In spine care, the cost of treatment can be high for patients, providers, and payers. In response, hospitals have focused on the development of specialized facilities designed to deliver high-quality, cost-effective healthcare called “centers of excellence.” These centers are an attempt to consolidate treatment for a specific specialty such as spine care under one facility, theoretically resulting in reduced costs due to cost-effective care delivered by acknowledged experts. This movement has been congruent with payers focusing on incentivized reimbursement plans. Payers such as the Centers for Medicare and Medicaid Services (CMS) have begun to pressure hospitals to produce cost savings or risk reduced payments. Payers are utilizing certain national quality measures and assessments to support their hospital reimbursement decisions. In this chapter, we will discuss the concept of “centers of excellence” and how they are applied to spine care. We will also discuss how payers have attempted to implement incentivized healthcare quality measures with payer-defined quality assessment.

Neuropathic pain (NP) affects approximately 4 million people in the United States with spinal cord injury (SCI) being a common cause. Matrix metalloproteinases (MMPs) play an integral role in mediating inflammatory responses, cellular signaling, cell migration, extracellular matrix degradation and tissue remodeling and repair. As such, they are major components in the pathogenesis of secondary injury within the central nervous system. Other gene regulatory pathways, specifically MAPK/extracellular signaling-regulated kinase (ERK) and Wnt/β-catenin, are also believed to participate in secondary injury likely intersect. The study aims to examine the MMP-2 signaling pathway associated with ERK and Wnt/β-catenin activity during contusion SCI (cSCI)-induced NP in a rat model. This is an experimental study investigating the implication of MMP-2 in SCI-induced NP and its association with the cellular and molecular changes in the interactions between extracellular signaling kinase and β-catenin. Adult Sprague-Dawley rats received cSCI injury by NYU impactor by dropping 10 g weight from a height of 12.5 mm. Locomotor functional recovery of injured rats was measured on post cSCI day 1, and weekly thereafter for 6 weeks using Basso, Beattie and Bresnahan scores. Thermal hyperalgesia (TH) testing was performed on days 21, 28, 35 and 42 post cSCI. The expression and/or activity of MMP-2, β-catenin and ERK were studied following harvest of spinal cord tissues between 3 and 6 weeks post cSCI. All experiments were funded by the department of Neurological Surgery at the University of Wisconsin, School of Medicine and Public Health having no conflict of interest. MMP-2 and β-catenin expression were elevated and gradually increased from days 21 to 42 compared to sham-operated rats and injured rats that did not exhibit TH. The expression of phosphorylated ERK (phospho-ERK) increased on day 21 but returned to baseline levels on day 42 whereas total ERK levels remained relatively unchanged and constant. Chronic NP is associated with changes in the expression of MMP-2, β-catenin and ERK. Our data suggest that the transient upregulation of phospho-ERK is involved in the initial upregulation of both β-catenin and MMP-2 following cSCI-induced NP states.

To assess microsurgical and diagnostic cerebral angiography modules and their corresponding objective assessment scales as educational tools for European neurosurgical residents at the European Association of Neurosurgical Societies Resident Vascular Neurosurgery course, which was held in Prague, Czech Republic, on September 2013. Microsurgical skills and cerebral angiography are fundamental skills in vascular neurosurgery. There is a need to develop a simulation-based curriculum focusing on these skills for neurosurgical trainees worldwide.The course consisted of 2 modules: microanastomosis and diagnostic cerebral angiography. In addition to an initial screening survey, each module was divided into 3 components: 1) a before didactic cognitive knowledge and technical skills testing, 2) a didactic lecture, and 3) an after didactic cognitive knowledge and technical skills testing. We compared the trainees' cognitive and technical scores from the before and after testing phases. Wilcoxon sum rank test was used to test statistical significance.The knowledge test median scores increased from 63% and 68% to 80% and 88% (P0.01) on the microanastomosis and cerebral angiography modules, respectively. The practical hands-on simulation assessment median scores increased from 42% and 50% to 50.5% and 68% (P0.01) on the microanastomosis and cerebral angiography modules, respectively.Our course suggests that a simulation-based vascular neurosurgery curriculum is feasible and may enhance resident knowledge and technical proficiency.

OBJECTIVE: To assess the impact of a simulation-based educational curriculum of 4 modules on neurosurgical trainees at the Neurological Societies of India annual meeting,whichwasheldinMumbai,India,inDecember2013. -METHODS: We developed a microanastomosis, anterior cervical discectomy and fusion (ACDF), posterior cervical fusion (PCF), and durotomy repair and their corresponding objective assessment scales. Each module was divided into 3 components: 1) a before didactic cognitive knowledge and technical skills testing, 2) a didactic lecture, and 3) an after didactic cognitive knowledgeand technicalskills testing. We compared the trainees’ cognitive and technical scores from the before and after testing phases. Wilcoxon sum rank test was used to test statistical significance. The incorporation of a simulation-based educational program into neurosurgical education curriculum has faced a number of barriers. It is essential to develop and assess the success and feasibility of simulation-based modules on neurosurgical residents. -RESULTS: The knowledge test median scores increased from 60%, 69% to 72%, and 60% to 80%, 85%, 90%, and 75% on the microanastomosis, ACDF, PCF, and durotomy modules, respectively (P < 0.05). The practical hands-on scores increased from 45%, 45% to 60%, and 65% to 62%, 68%, 81%, and 70% on the microanastomosis, ACDF, PCF, and durotomy modules, respectively (P < 0.05).

Neuropathic pain, especially that resulting from spinal cord injury, is a tremendous clinical challenge. A myriad of biological changes have been implicated in producing these pain states including cellular interactions, extracellular proteins, ion channel expression, and epigenetic influences. Physiological consequences of these changes are varied and include functional deficits and pain responses. Developing therapies that effectively address the cause of these symptoms require a deeper knowledge of alterations in the molecular pathways. Matrix metalloproteinases and tissue inhibitors of metalloproteinases are two promising therapeutic targets. Matrix metalloproteinases interact with and influence many of the studied pain pathways. Gene expression of ion channels and inflammatory mediators clearly contributes to neuropathic pain. Localized and time dependent targeting of these proteins could alleviate and even prevent neuropathic pain from developing. Current therapeutic options for neuropathic pain are limited primarily to analgesics targeting the opioid pathway. Therapies directed at molecular targets are highly desirable and in early stages of development. These include transplantation of exogenously engineered cell populations and targeted gene manipulation. This review describes specific molecular targets amenable to therapeutic intervention using currently available delivery systems.