Camptocormia in Parkinson's Disease: Systematic Review of Management Using Spine Surgery.

OBJECTIVE: Postural abnormalities are a debilitating symptom of Parkinson's disease (PD) that may require spinal intervention. Camptocormia is a unique abnormality most seen in PD, defined by a severe forward-flexion of the trunk that completely resolves when supine. The condition presents a challenge due to an undefined pathophysiology and optimal therapeutic approach in a high-risk patient population. In this study, the authors systematically reviewed the literature regarding the use of spine surgery for the treatment of camptocormia in PD. METHODS: PubMed, Embase, Web of Science, and Cochrane Library were systematically queried for studies involving spine surgery as treatment of PD-associated camptocormia. Studies involving nonsurgical management, deep brain stimulation (DBS), non-camptocormic PD patients undergoing surgery, or were out of scope were excluded. RESULTS: The search resulted in 5 studies, with a total of 19 PD patients with camptocormia who underwent spine surgery (73.7% female). The mean age was 69.5 years (range, 59 - 83), and mean PD duration was 69.5 months (range, 36 - 84). Out of 19 patients, 11 required surgical revision (57.9%), with an average of 0.68 revisions per patient (range, 0-2). Radiographic and patient-reported outcomes were inconsistently reported yet showed improvement. Ultimately, 18 patients were reported to have positive outcomes. CONCLUSION: Despite an increased risk of complication and revision that is inherent to PD patients, spine surgery has been proven as a reasonable alternative that should be prospectively studied further, as 18/19 patients had favorable outcomes.

Association Between Preoperative Cannabis Use and Increased Rate of Revision Surgery Following Spinal Fusion: A Systematic Review and Meta-Analysis.

The use of cannabis as a method of chronic pain relief has skyrocketed since its legalization in states across the United States. Clinicians currently have a limited scope regarding the effectiveness of marijuana on surgical procedures. This systematic review aims to determine the effect of current cannabis use on the rate of failure of spinal fusions and overall surgical outcomes. A systematic review was performed in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) statement. PubMed, Embase, and Scopus were searched, identifying studies assessing spinal fusion with reported preoperative cannabis use. Outcomes of interest included reoperation due to fusion failure or pseudoarthrosis with a follow-up time of at least six months. Subgroups of cervical fusions alone and lumbar fusions alone were also analyzed. Certainty in evidence and bias was assessed using the GRADE criteria and ROBINS-I tool (PROSPERO #CRD42023463548). Four studies met the inclusion criteria, with a total of 788 patients (188 in the cannabis user group and 600 in the non-user group). The rate of revision surgery among cannabis users was higher than that in non-users for all spinal fusions (RR: 3.58, 95% CI: 1.67 to 7.66, p = 0.001). For cervical fusions alone, there remained a higher rate of revision surgery for cannabis users compared to non-users (RR: 4.47, 95% CI: 1.93 to 10.36, p = 0.0005). For lumbar fusions alone, there was no difference in the rates of revision surgery between cannabis users and non-users (RR: 1.21, 95% CI: 0.28 to 7.73, p = 0.79). Cannabis use was shown to be associated with a higher rate of pseudoarthrosis revisions in spinal fusions on meta-analysis. On subgroup stratification by spine region, cannabis use remained associated with pseudoarthrosis revisions on cervical fusions alone but not lumbar fusions alone. Further research with larger, randomized studies is required to fully elucidate the relationship between cannabis use and fusion, both in general and by spinal region.

Navigating the Neurosurgery Match Process: Insights from the National Resident Matching Program - Program Director Surveys.

OBJECTIVE: Neurosurgery is one of the most competitive specialties, and navigating the match process is often challenging for aspiring applicants. Here, we analyze insights from the National Resident Matching Program Director Surveys, illustrating evolving trends in applicant selection for interviews and for the ranking process, and providing a comparison with other specialties. METHODS: We evaluated 7 surveys administered from 2012 to 2022. Six biennial surveys reported on factors influencing interview and ranking processes, while all 7 surveys included data about the program director (PD)'s attitude toward United States Medical Licensing Examination (USMLE) test scores. RESULTS: The response rate of PDs decreased over the years. The most cited factor for interviews included specialty-specific recommendation letters (95%), USMLE Step 1 scores (91%), and interest in research (78%). A recent decline in emphasis on USMLE Step 1 scores coincided with a growing reliance on USMLE Step 2 scores. Award in basic science held significant esteem to a subset of programs. Personal characteristics dominated for ranking, with faculty interaction (89%), interpersonal skills (89%), and house staff interaction (85%) being the most important. Yet, PDs reported a difficulty in assessing interpersonal skills through virtual interviews. CONCLUSIONS: Our analysis revealed the pervasive importance of specialized endorsements and academic achievements when screening applicants for the interview process. A shift in emphasis toward the USMLE Step 2 became apparent. Personal characteristics, on the other hand, seemed crucial to make a match and rank high among the pool of interviewed applicants. We uncovered difficulties in assessing these characteristics through virtual interviews.

Surgical management of spinal metastases from primary thyroid carcinoma: Demographics, clinical characteristics, and treatment outcomes - A retrospective analysis.

Objective: Metastatic spinal tumors represent a rare but concerning complication of primary thyroid carcinoma. We identified demographics, metastatic features, outcomes, and treatment strategies for these tumors in our institutional cohort. Materials and Methods: We retrospectively reviewed patients surgically treated for spinal metastases of primary thyroid carcinoma. Demographics, tumor characteristics, and treatment modalities were collected. The functional outcomes were quantified using Nurik, Modified Rankin, and Karnofsky Scores. Results: Twelve patients were identified who underwent 17 surgeries for resection of spinal metastases. The primary thyroid tumor pathologies included papillary (4/12), follicular (6/12), and Hurthle cell (2/12) subtypes. The average number of spinal metastases was 2.5. Of the primary tumor subtypes, follicular tumors averaged 2.8 metastases at the highest and Hurthle cell tumors averaged 2.0 spinal metastases at the lowest. Five patients (41.7%) underwent preoperative embolization for their spinal metastases. Seven patients (58.3%) received postoperative radiation. There was no significant difference in progression-free survival between patients receiving surgery with adjuvant radiation and surgery alone (P = 0.0773). Five patients (41.7%) experienced postoperative complications. Two patients (16.7%) succumbed to disease progression and two patients (16.7%) experienced tumor recurrence following resection. Postsurgical mean Nurik scores decreased 0.54 points, mean Modified Rankin scores decreased 0.48 points, and mean Karnofsky scores increased 4.8 points. Conclusion: Surgery presents as an important treatment modality in the management of spinal metastases from thyroid cancer. Further work is needed to understand the predictive factors for survival and outcomes following treatment.

The demographic, clinical, and management differences between traumatic dens fracture patients with and without simultaneous atlas fractures.

Introduction: Atlas fractures often accompany traumatic dens fractures, but existing literature on the management of simultaneous atlantoaxial fractures is limited. Methods: We examined all patients with traumatic dens fractures at our institution between 2008 and 2018. We used multivariable logistic regression and ordinal logistic regression to identify factors independently associated with presentation with a simultaneous atlas fracture, as well myelopathy severity, fracture nonunion, and selection for surgery. Results: Two hundred and eighty-two patients with traumatic dens fractures without subaxial fractures were identified, including 65 (22.8%) with simultaneous atlas fractures. The distribution of injury mechanisms differed between groups (χ2 P = 0.0360). On multivariable logistic regression, dens nonunion was positively associated with type II fractures (odds ratio [OR] = 2.00, P = 0.038) and negatively associated with having surgery (OR = 0.52, P = 0.049), but not with having a C1 fracture (P = 0.3673). Worse myelopathy severity on presentation was associated with having a severe injury severity score (OR = 102.3, P < 0.001) and older age (OR = 1.28, P = 0.002), but not with having an atlas fracture (P = 0.2446). Having a simultaneous atlas fracture was associated with older age (OR = 1.29, P = 0.024) and dens fracture angulation (OR = 2.62, P = 0.004). Among patients who underwent surgery, C1/C2 posterior fusion was the most common procedure, and having a simultaneous atlas fracture was associated with selection for occipitocervical fusion (OCF) (OR = 14.35, P = 0.010). Conclusions: Among patients with traumatic dens, patients who have simultaneous atlas fractures are a distinct subpopulation with respect to age, mechanism of injury, fracture morphology, and management. Traumatic dens fractures with simultaneous atlas fractures are independently associated with selection for OCF rather than posterior cervical fusion alone.

Chemoprophylactic Anticoagulation After Spine Surgery Does Not Increase Epidural Hematoma Risk: A Propensity-matched Analysis.

STUDY DESIGN: A retrospective cohort study. OBJECTIVE: To calculate the magnitude of any increased risk of epidural hematoma (EDH) associated with chemoprophylactic anticoagulation (chemoprophylaxis), if any. SUMMARY OF BACKGROUND DATA: Chemoprophylaxis for the prevention of venous thromboembolic events may be associated with an increased risk of EDH after spine surgery. MATERIALS AND METHODS: A total of 6869 consecutive spine surgeries performed at our institution were identified, and clinical and demographic data were collected. We identified cases in which symptomatic EDHs were evacuated within 30 days postoperatively. Patients receiving chemoprophylaxis and controls were matched using K-nearest neighbor propensity score matching to calculate the effect of anticoagulation on the rate of postoperative EDH. RESULTS: After propensity score matching, 1071 patients who received chemoprophylaxis were matched to 1585 controls. Propensity scores were well balanced between populations (Rubin B=20.6, Rubin R=1.05), and an 89.6% reduction in bias was achieved, with a remaining mean bias of 3.2%. The effect of chemoprophylaxis on EDH was insignificant ( P =0.294). Symptomatic EDH was independently associated with having a transfusion [odds ratio (OR)=7.30 (1.15, 46.20), P =0.035], having thoracic-level surgery [OR=41.19 (3.75, 452.4), P =0.002], and increasing body mass index [OR=1.44 (1.04, 1.98), P =0.028] but was not associated with chemoprophylaxis. Five out of 13 patients who developed EDH (38.5%) were receiving some form of anticoagulation, including 1 patient on therapeutic anticoagulation, 1 concurrently on aspirin and chemoprophylaxis, and 2 who were also found to have developed thrombocytopenia postoperatively. The median time on anticoagulation before EDH was 8.1 days. A higher proportion of patients who developed EDH also developed venous thromboembolic events than the general population [38.5% vs. 2.4%, OR=25.34 (9.226, 79.68), P <0.0001], and 1 EDH patient died from pulmonary embolism while off chemoprophylaxis. CONCLUSIONS: Chemoprophylactic anticoagulation did not cause an increase in the rate of spinal EDH in our patient population.

C1-C2 Posterior Screw-Rod Fixation.

Multiple approaches for instrumentation of the upper cervical spine have evolved to treat atlantoaxial instability which, until the 20th century, was largely considered to be inoperable and managed nonsurgically with immobilization. Surgeons set out to provide safe and effective approaches in a clearly dangerous and technically complex anatomic region. It is important to provide a historical analysis of the evolution of techniques that have shaped C1-C2 instrumentation, and how the diligent efforts of surgeons to improve the biomechanical stability and fusion rates of their constructs eventually led to the prevailing Harms technique. This technique is explored by describing its surgical steps, alternative techniques, and associated outcomes. For successful instrumentation of the atlantoaxial joint, a comprehensive understanding of spinal biomechanics, surgical techniques, and anatomic variations is imperative for surgeons to develop a tailored plan for each patient's individual pathology and anatomy.

Adolescent Idiopathic Scoliosis and Pregnancy.

Objective This study examined the interaction between adolescent idiopathic scoliosis (AIS) and pregnancy, focusing on pregnancy outcomes, changes in back pain, and anesthesia use. Methods A retrospective analysis was conducted on adult patients with AIS who gave birth at our institution between 2006 and 2022. Results A total of 163 AIS patients with 263 pregnancies were included. The median age at delivery was 33 (range 18 to 50) years. Among 157 patients with information on prior scoliosis treatment, 66.9% had not received treatment, 20.4% had undergone spinal fusion, and 12.7% had received bracing. Of the 260 pregnancies with available data, 90.4% were delivered at term and 8.5% were preterm. Of the 257 pregnancies with information on anesthesia type, 35.0% received epidural anesthesia, 17.9% received spinal anesthesia, 37.7% received combined spinal and epidural anesthesia, 8.2% received no anesthesia, and 1.2% received intravenous or general anesthesia. Difficulty administering neuraxial anesthesia was reported in 6.1% of cases, and these patients were less likely to receive combined spinal and epidural anesthesia (6.3% versus 39.8%, p = 0.0123). Among 116 cases with recorded back pain during pregnancy, 67.2% reported increased pain, 31.9% reported similar pain, and one patient reported decreased pain. Of the 16 patients with pre and postpartum radiographs, eight showed a Cobb angle increase ≥ 3°, with five patients having an increase ≥ 5°. Conclusions Pregnancy can exacerbate back pain and pose challenges for neuraxial anesthesia in some AIS patients. Further large-scale, multi-institutional studies with standardized data collection are needed to fully understand the impact of pregnancy on AIS.

Odontoid fracture type and angulation affect nonunion risk, but comminution and displacement do not: A propensity score matched analysis of fracture morphology.

OBJECTIVE: Odontoid fractures disproportionately affect older patients who have high surgical risk, but also high rates of fracture nonunion. To guide surgical decision-making, we quantified the effect of fracture morphology on nonunion among nonoperatively managed, traumatic, isolated odontoid fractures. METHODS: We examined all patients with isolated odontoid fractures treated nonoperatively at our institution between 2010 and 2019. Multivariable regression and propensity score matching were used to quantify the effect of fracture type, angulation, comminution, and displacement on bony healing by 26 weeks from injury. RESULTS: 303 consecutive traumatic odontoid fracture patients were identified, of whom 163 (53.8 %) had isolated fractures that were managed nonoperatively. Selection for nonoperative management was more likely with older age (OR=1.31 [1.09, 1.58], p = 0.004), and less likely with higher fracture angle (OR=0.70 [0.55, 0.89], p = 0.004), or higher presenting Nurick scores (OR=0.77 [0.62, 0.94], p = 0.011). Factors associated with nonunion at 26 weeks were fracture angle (OR=5.11 [1.43, 18.26], p = 0.012) and Anderson-D'Alonzo Type II morphology (OR=5.79 [1.88, 17.83], p = 0.002). Propensity score matching to assess the effect of type II fracture, fracture angulation> 10o, displacement≥ 3 mm, and comminution all yielded balanced models (Rubin's B<25.0, 0.5  10o (p = 0.015), and there was an 18.2 % lower rate of bony healing for each 10o increase in fracture angle. Fracture displacement≥ 3 mm and comminution had no significant effect. CONCLUSION: Type II fracture morphology and fracture angle > 10o significantly increase nonunion among nonoperatively managed isolated traumatic odontoid fractures, but fracture comminution and displacement ≥ 3 mm do not.

Outcome Reporting in Spine Surgery: A Review of Historical and Emerging Trends.

The general objectives of spine surgery are to alleviate pain, restore neurologic function, and prevent or treat spinal deformities or instability. The accumulating expanse of outcome measures has allowed us to more objectively quantify these variables and, therefore, gauge the success of treatments, ultimately improving the quality of the delivered health care. It has become increasingly evident that spinal conditions and their accompanying interventions affect all aspects of a patient's life, including their physical, mental, emotional, and social well-being. This underscores the challenge of creating clinically relevant and accurate outcome measures in spine care, and the reason why there is a growing recognition of the importance of subjective measures such as patient-reported outcome measures, that consider a patients' health-related quality of life. Subjective measures provide valuable insights into patient experiences and perceptions of treatment outcomes, whereas objective measures provide a reproducible glimpse into key radiographic and clinical parameters that are associated with a successful outcome. In this narrative review, we provide a detailed analysis of the most common subjective and objective outcome measures employed in spine surgery, with a special focus on their current role as well as the possible future of outcome reporting.

Traumatic Dens Fracture Patients Comprise Distinct Subpopulations Distinguished by Differences in Age, Sex, Injury Mechanism and Severity, and Outcome.

BACKGROUND: Dens fractures are an increasingly common injury, yet their epidemiology and its implications remain underexamined. METHODS: We retrospectively analyzed all traumatic dens fracture patients managed at our institution over a 10-year period, examining demographic, clinical, and outcomes data. Patient subsets were compared across these parameters. RESULTS: Among 303 traumatic dens fracture patients, we observed a bimodal age distribution with a strong goodness of fit centered at age 22.3 ± 5.7 (R = 0.8781) and at 77.7 ± 13.9 (R = 0.9686). A population pyramid demonstrated a bimodal distribution among male patients, but not female patients, which was confirmed with a strong goodness of fit for male patient subpopulations age <35 (R = 0.9791) and age ≥35 (R = 0.8843), but a weaker fit for a second female subpopulation age <35. Both age groups were equally likely to undergo surgery. Patients younger than age 35 were more likely to be male (82.4% vs. 46.9%, odds ratio [OR] = 5.29 [1.54, 17.57], P = 0.0052), have motor vehicle collision as their mechanism of injury (64.7% vs. 14.1%, OR = 11.18 [3.77, 31.77], P < 0.0001), and to have a severe trauma injury severity score (17.6% vs. 2.9%, OR = 7.23 [1.88, 28.88], P = 0.0198). Nevertheless, patients age <35 were less likely to have fracture nonunion at follow (18.2% vs. 53.7%, OR = 0.19 [0.041, 0.76], P = 0.0288). CONCLUSIONS: The dens fracture patient population comprises 2 subpopulations, distinguished by differences in age, sex, injury mechanism and severity, and outcome, with male dens fracture patients demonstrating a bimodal age distribution. Young, male patients were more likely to have high-energy injury mechanisms leading to severe trauma, yet were less likely to have fracture nonunion at follow-up.

Variation in academic neurosurgery departments' #neurosurgery social media influence.

Background: Social media use is increasingly common among academic neurosurgery departments, but its relationship with academic metrics remains underexamined. Methods: We examine the relationship between American academic neurosurgery departments' number of followers on Twitter, Instagram, and Facebook and the following academic metrics: Doximity Residency rankings, US News & World Report rankings (USNWR) of their affiliated medical schools, and the amount of NIH funding of those schools. Results: Few departments had disproportionate number of followers. A greater proportion of programs had Twitter accounts (88.9%) than had Instagram (72.2%) or Facebook (51.9%) accounts (p=0.0001). Programs identified as "Influencers" had more departmental NIH funding (p=0.044), more institutional NIH funding (p=0.035), better Doximity residency rankings (p=0.044), and better affiliated medical school rankings (p=0.002). Number of Twitter followers had the strongest correlation with academic metrics, yet only modest correlations were identified to departmental NIH funding (R=0.496, p=0.0001), institutional NIH funding (R=0.387, p=0.0072), Doximity residency rank (R=0.411, p=0.0020), and affiliated medical school ranking (R=0.545,p<0.0001). On multivariable regression, only being affiliated with a medical school in the top quartile on the USNWR rankings, rather than neurosurgery departmental metrics, predicted having more Twitter (OR=5.666, p=0.012) and Instagram (OR=8.33, p=0.009) followers. Conclusion: American academic neurosurgery departments preferentially use Twitter over Instagram or Facebook. Their Twitter or Instagram presences are associated with better performance on traditional academic metrics. However, these associations are modest, suggesting that other factors contribute to a department's social media influence. A department's affiliated medical school may contribute to the department's social media brand.

Surgery Decreases Nonunion, Myelopathy, and Mortality for Patients With Traumatic Odontoid Fractures: A Propensity Score Matched Analysis.

BACKGROUND: Existing literature suggests that surgical intervention for odontoid fractures is beneficial but often does not control for known confounding factors. OBJECTIVE: To examine the effect of surgical fixation on myelopathy, fracture nonunion, and mortality after traumatic odontoid fractures. METHODS: We analyzed all traumatic odontoid fractures managed at our institution between 2010 and 2020. Ordinal multivariable logistic regression was used to identify factors associated with myelopathy severity at follow-up. Propensity score analysis was used to test the treatment effect of surgery on nonunion and mortality. RESULTS: Three hundred and three patients with traumatic odontoid fracture were identified, of whom 21.6% underwent surgical stabilization. After propensity score matching, populations were well balanced across all analyses (Rubin's B < 25.0, 0.5 < Rubin's R < 2.0). Controlling for age and fracture angulation, type, comminution, and displacement, the overall rate of nonunion was lower in the surgical group (39.7% vs 57.3%, average treatment effect [ATE] = -0.153 [-0.279, -0.028], P = .017). Controlling for age, sex, Nurick score, Charlson Comorbidity Index, Injury Severity Score, and selection for intensive care unit admission, the mortality rate was lower for the surgical group at 30 days (1.7% vs 13.8%, ATE = -0.101 [-0.172, -0.030], P = .005) and at 1 year was 7.0% vs 23.7%, ATE = -0.099 [-0.181, -0.017], P = .018. Cox proportional hazards analysis also demonstrated a mortality benefit for surgery (hazard ratio = 0.587 [0.426, 0.799], P = .0009). Patients who underwent surgery were less likely to have worse myelopathy scores at follow-up (odds ratio = 0.48 [0.25, 0.93], P = .029). CONCLUSION: Surgical stabilization is associated with better myelopathy scores at follow-up and causes lower rates of fracture nonunion, 30-day mortality, and 1-year mortality.

Functional Anatomy and Biomechanics of the Craniovertebral Junction.

The craniovertebral junction (CVJ) involves the atlas, axis, and occiput along with the atlanto-occipital and atlantoaxial joints. The anatomy and neural and vascular anatomy of the junction render the CVJ unique. Specialists treating disorders that affect the CVJ must appreciate its intricate anatomy and should be well versed in its biomechanics. This first article in a three-article series provides an overview of the functional anatomy and biomechanics of the CVJ.

Biological principles of adult degenerative scoliosis.

The global aging population has led to an increase in geriatric diseases, including adult degenerative scoliosis (ADS). ADS is a spinal deformity affecting adults, particularly females. It is characterized by asymmetric intervertebral disc and facet joint degeneration, leading to spinal imbalance that can result in severe pain and neurological deficits, thus significantly reducing the quality of life. Despite improved management, molecular mechanisms driving ADS remain unclear. Current literature primarily comprises epidemiological and clinical studies. Here, we investigate the molecular mechanisms underlying ADS, with a focus on angiogenesis, inflammation, extracellular matrix remodeling, osteoporosis, sarcopenia, and biomechanical stress. We discuss current limitations and challenges in the field and highlight potential translational applications that may arise with a better understanding of these mechanisms.

Outpatient telemedicine in neurosurgery: 15,677 consecutive encounters in a comparative analysis of its effectiveness and impact on the surgical conversion rate.

OBJECTIVE: The coronavirus disease 2019 (COVID-19) pandemic has necessitated the use of telehealth visits (THVs). The effects on neurosurgical practice have not been well characterized, especially concerning new-patient THVs. Therefore, the authors of this study reviewed their institution's experience with outpatient clinic visits and THVs from before the COVID-19 pandemic to the present to focus on clinical metrics, rates of surgery, and the effects of implementing THVs in order to better understand their implications for clinical practice as more data emerge over time. METHODS: The authors reviewed 15,677 consecutive new outpatient in-person visits (IPVs), THVs, and neurosurgical procedures/cases proceeding from their institution between 2018 and 2022 for trends and associations related to THVs. RESULTS: Among spine patients, there was no difference in the proportion of encounters that led to surgery (surgical conversion rate) between THVs and IPVs (p = 0.49). Among cranial patients, THVs were negatively associated with conversion (OR 0.73, p = 0.03). On average, patients using THVs lived further from the hospital (p < 0.001); however, the patient catchment area appeared unchanged. The median distance to the hospital among THV patients was counterbalanced by a decreased distance for spine patients pursing IPVs (p < 0.001), with no significant change to case volume. There was no change in distance to the hospital among cranial patients. For both cranial and spine patients, surgical conversion was more likely among those who lived a great distance from the hospital if their initial encounter was an IPV (p = 0.007 and < 0.001, respectively). However, there was no relationship between distance from the hospital and surgical conversion among THV patients (p = 0.565). The availability of THVs did not significantly affect follow-up time (p = 0.837). For new patients at IPVs, there was no difference in time to the operating room between cranial and spine cases; for new patients at THVs, however, time to the operating room was significantly faster for cranial cases than for spine cases (p = 0.0018). CONCLUSIONS: Compared to IPVs, THVs lead to decreased surgical conversion for cranial patients but not spine patients. THVs do not appear to increase the catchment area. For patients who live far from the hospital, an IPV is associated with surgical conversion. Surgical conversion is faster following cranial THVs than after spine THVs. THVs did not increase the duration of follow-up.

Advances, Challenges, and Future Directions in the Management of Craniovertebral Junction Pathologies.

In this third article in a 3-article series on the craniocervical junction, we define the terms "basilar impression," "cranial settling," "basilar invagination," and "platybasia," noting that these terms are often used interchangeably but represent distinct entities. We then provide examples that represent these pathologies and treatment paradigms. Finally, we discuss the challenges and future direction in the craniovertebral junction surgery space.

An Approach to Managing Disorders Affecting the Craniovertebral Junction.

The craniovertebral junction (CVJ), or the "first junction," can be affected by a variety of pathological states. Some of these conditions could represent a gray area in that they can be treated by general neurosurgeons or such specialists as skull base or spinal surgeons. However, some conditions are best managed with a multidisciplinary approach. The importance of in-depth knowledge of the anatomy and biomechanics of this junction cannot be overemphasized. Identifying what represents clinical stability or instability is key to successful diagnosis and, hence, treatment. In this report, the second in a 3-article series, we describe our approach to managing CVJ pathologies in a case-based fashion to illustrate key concepts.

Chemoprophylactic Anticoagulation Following Lumbar Surgery Significantly Reduces Thromboembolic Events After Instrumented Fusions, Not Decompressions.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: To quantify any reduction in venous thromboembolic events (VTEs) caused by chemoprophylaxis among lumbar surgery patients. SUMMARY OF BACKGROUND DATA: Chemoprophylactic anticoagulation (chemoprophylaxis) is used to prevent VTE after lumbar surgery. However, the treatment effect of chemoprophylaxis has not been reported among spine surgery patients, as conventional statistical methods preclude such inferences. MATERIALS AND METHODS: A total of 1243 consecutive lumbar fusions and 1433 noninstrumented lumbar decompressions performed at our institution over a six-year period were identified, and clinical and demographic data were collected, including on VTE events within 30 days postoperatively. Instrumented lumbar fusions and noninstrumented lumbar surgeries were analyzed separately. Patients who were given chemoprophylaxis (treatment) and controls were matched according to known VTE risk factors, including age, body mass index, sex, diabetes, chronic kidney disease, history of VTE, estimated blood loss, length of surgery, transfusion, whether surgery was staged, and whether surgery used an anterior approach. K-nearest neighbor propensity score matching was performed, and the treatment effect of chemoprophylaxis was calculated. RESULTS: Unadjusted, there was no difference in the rate of VTE between treatment and controls in either population. Baseline clinical and demographic characteristics differed significantly between treatment and control groups. In all, 575 lumbar fusion patients and 435 noninstrumented lumbar decompression patients were successfully propensity score matched, yielding balanced models (Rubin B <25, 0.560% reduction in known bias for both populations. The treatment effect of chemoprophylaxis after lumbar fusion in our patient population was a reduction in VTE incidence from 9.4% to 4.2% ( P <0.05), and propensity score adjusted regression confirmed a reduced odds of VTE with chemoprophylaxis (odds ratio=0.37, P =0.035). The treatment effect was not significant for noninstrumented lumbar decompression patients. CONCLUSION: Among patients undergoing instrumented lumbar fusions, chemoprophylactic anticoagulation causes a significant reduction in VTE, but causes no significant reduction among patients undergoing noninstrumented lumbar decompression.